Next Article in Journal
HLA-DPB1 Reactive T Cell Receptors for Adoptive Immunotherapy in Allogeneic Stem Cell Transplantation
Next Article in Special Issue
Molecular Chaperones and Proteolytic Machineries Regulate Protein Homeostasis in Aging Cells
Previous Article in Journal
Erratum: Bharti D., et al. In Vitro Generation of Oocyte Like Cells and Their In Vivo Efficacy: How Far We have been Succeeded. Cells 2020, 9, 557
Previous Article in Special Issue
Molecular Mechanisms of Heat Shock Factors in Cancer
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Cells
Volume 9
Issue 5
10.3390/cells9051263
cells-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles thumb_up
...
Endorse textsms
...
Comment
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Review

Membrane-Associated Heat Shock Proteins in Oncology: From Basic Research to New Theranostic Targets

by
Maxim Shevtsov
1,2,3,4,5,6,*,
Zsolt Balogi
7,
William Khachatryan
4,
Huile Gao
8,
László Vígh
9 and
Gabriele Multhoff
1
1
Center for Translational Cancer Research Technische Universität München (TranslaTUM), Radiation Immuno-Oncology group, Klinikum rechts der Isar, Einstein Str. 25, 81675 Munich, Germany
2
Institute of Cytology of the Russian Academy of Sciences (RAS), Tikhoretsky ave., 4, 194064 St. Petersburg, Russia
3
Pavlov First Saint Petersburg State Medical University, L. Tolstogo str. 6/8, 197022 St. Petersburg, Russia
4
Almazov National Medical Research Centre, Polenov Russian Scientific Research Institute of Neurosurgery, Mayakovskogo str. 12, 191104 St. Petersburg, Russia
5
National Center for Neurosurgery, Turan Ave., 34/1, Nur-Sultan 010000, Kazakhstan
6
Far Eastern Federal University, Russky Island, 690000 Vladivostok, Russia
7
Institute of Biochemistry and Medical Chemistry, Medical School, University of Pecs, Szigeti str. 12, 7624 Pecs, Hungary
8
Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610064, China
9
Institute of Biochemistry, Biological Research Centre, Temesvári krt. 62, 6726 Szeged, Hungary
*
Author to whom correspondence should be addressed.
Cells 2020, 9(5), 1263; https://doi.org/10.3390/cells9051263
Submission received: 30 March 2020 / Revised: 16 May 2020 / Accepted: 18 May 2020 / Published: 20 May 2020
(This article belongs to the Special Issue Molecular Chaperones: Cancer and Cell Death)
Browse Figure
Versions Notes

Abstract

:
Heat shock proteins (HSPs) constitute a large family of conserved proteins acting as molecular chaperones that play a key role in intracellular protein homeostasis, regulation of apoptosis, and protection from various stress factors (including hypoxia, thermal stress, oxidative stress). Apart from their intracellular localization, members of different HSP families such as small HSPs, HSP40, HSP60, HSP70 and HSP90 have been found to be localized on the plasma membrane of malignantly transformed cells. In the current article, the role of membrane-associated molecular chaperones in normal and tumor cells is comprehensively reviewed with implications of these proteins as plausible targets for cancer therapy and diagnostics.

1. Introduction

Heat shock protein (HSP) families consist of constitutive and stress-inducible members such as HSPB (small HSP), DNAJ (HSP40), HSPA (HSP70), HSPC (HSP90), HSPH (HSP110) and their related chaperokines HSPD/E (HSP60/HSP10) and CCT (TRiC) [1]. HSPs reside in the following three intracellular compartments and are also localized extracellularly where they fulfill various tasks: (1) cytosol (including various intracellular organelles (e.g., mitochondria); (2) nucleus; (3) and plasma membrane. Cytosolic chaperones play important roles in intracellular protein homeostasis including folding, unfolding and transport of denatured proteins and regulation of apoptosis. Upon stress such as hyperthermia, ionizing radiation, hypoxia, acidosis, and nutrient deprivation [2,3], their synthesis is rapidly upregulated by an activation of different heat shock factors (HSFs) in normal and tumor cells, although tumor cells per se exhibit elevated HSP levels already under physiological conditions due to their challenging microenvironment. A high HSP expression in various types of cancer cells is associated with tumor progression and resistance to anti-cancer therapies (including radio-/chemotherapies) [4]. Furthermore, upon stress (e.g., anoxia and hyperthermia) HSPs rapidly translocate into the nucleus, where they support their synthesis in an autocrine loop [5,6,7]. Extracellular HSPs were reported to play a role in both innate and adaptive anti-cancer immunity, implicating their possible application for development of immunotherapeutic approaches [8,9]. Thus, Hsp70 and Hsp90 proteins were shown to stimulate anti-tumor responses by facilitating cross-presentation of antigenic peptides via major histocompatibility complex (MHC) class I molecules, with subsequent induction of a CD8+ T cell-mediated immune response [9]. Furthermore, molecular chaperones of the HSP70 family can enhance cytolytic, migratory and proliferative capacities of natural killer (NK) cells even in the absence of immunogenic peptides [8,9].
Apart from their intracellular localization, various representatives of the major HSP families are reported to be expressed on the plasma membrane of cells [10,11,12,13,14]. Comprehensive profiling of the cell surface proteome of different tumor cell types (e.g., A549 lung adenocarcinoma, SH-SY5Y neuroblastoma, LoVo colon adenocarcinoma, Sup-B15 acute lymphoblastic leukemia, CX colon carcinoma and SKOV3 ovarian tumor cells) revealed the presence of numerous chaperones including HSP70, GRP75, GRP78, HSP60, HSP54, HSP27, and protein disulfide isomerase (PDI) on the plasma membrane [10,15]. Subsequent studies demonstrated the presence of other chaperones including HSP90, GRP96, HSP40, and calreticulin on tumor cell membranes [16,17,18]. Residents of the endoplasmatic reticulum (ER) (HSP47, GRP78, binding immunoglobulin protein (BiP), ERP57, PDI, GRP96, and calreticulin) gained relocalization signals (e.g., a KDEL sequence at the carboxy terminus) [17] or post-translational modification, which enables their transport to the plasma membrane (reviewed in [19]). However, for cytosolic HSPs (HSP70, HSP60, and HSP40), the exact mechanisms of protein transport, translocation through the membrane, and anchorage in the plasma membrane remain to be determined. In the current review, the role of cell surface-bound HSPs on tumor cells is discussed with respect to their possibility for development of novel diagnostic and therapeutic tools in oncology as well as their potential function in tumor progression and resistance to anti-cancer therapies.

2. HSP70 Family

The (1) inducible form of Hsp70 (HSPA1A) (but not the constitutive form, Hsc70) and (2) the ER-localized glucose-regulated protein 78 (GRP78) (HSPA5) (Figure 1) have been found to be localized on the plasma membrane of a variety of tumor cell types including primary glioblastomas [20], squamous cell carcinoma of the head and neck (HNSCC) and non-small-cell lung carcinoma (NSCLC) [21,22], human oral dysplasia and squamous cell carcinoma [23], colorectal and gastric cancer [24], pancreatic carcinoma [25], osteosarcoma [26], and acute myelogenous leukemia [25,27]. The transport of cytosolic Hsp70 to the plasma membrane occurs most likely via non-classical, vesicular mechanisms, since inhibitors of the post-Golgi membrane traffic by monensin or brefeldin A (BFA) do not impede the expression of membrane-bound Hsp70 (mHsp70) [28,29]. In a more recent study by Evdokimovskaya et al., application of BFA did not interfere with the secretion of Hsp70 (as well as Hsc70) by baby hamster kidney (BHK-21) cells, thus indicating a non-classical pathway of chaperone release [30].
Intriguingly, in patients with gastric and colon carcinomas mHsp70 expression correlated with an improved overall survival (OS), whereas a negative association was reported in squamous cell carcinoma and lower rectal cancer [24]. It is speculated that these contradictory results may be attributed to differences in the route of metastasis in these tumors or the complex role of Hsp70 in tumorigenesis. On the one hand, the hepatic route of metastasis of gastric and colon carcinomas might enable liver-residing CD56+ NK cells to deplete mHsp70+ tumor cells, and thereby might improve clinical outcome. On the other hand, mHsp70 was proposed to mediate a protective role against ionizing radiation by stabilizing lysosomal membranes (via enhancing the activity of acid spingomyelinase) [15,31,32], which protects tumor cells from lysosome-dependent cell death [33]. It has been shown that mHsp70 participates in non-classical secretory pathways [34,35] and facilitates clathrin-independent endocytosis [36]. An interaction of lysin-rich domains in the substrate-binding domain of Hsp70 directs Hsp70 monomers in an anti-parallel orientation [37], which facilitates dimerization, interaction with other co-chaperones (Hsp40, Hsp90, Hop) and HSP client proteins [38]. Presumably, post-translational modifications, especially in the substrate-binding domain (SBD), may also regulate Hsp70–lipid interactions, but further studies are required to prove this hypothesis [39,40,41,42,43]. Depletion of the C-terminal helical lid subdomain (ΔLSBD641 variant without the linker) also impairs Hsp70 oligomerization [37], which counteracts mHsp70-mediated facilitation of endocytosis [36]. In a B16/F10 mouse melanoma model, already 60 min following intravenous injection of rhHsp70-I123 the radiolabeled chaperone accumulated inside the tumor [44]. Cellular uptake of Hsp70 itself may also require its oligomerization on the cell surface [36,44,45,46,47,48,49].
Epitope mapping of the Hsp70-specific antibody cmHsp70.1 (aa 453–460), which detects cell surface bound Hsp70 on viable tumor cells with intact plasma membrane [50], revealed that the epitope of Hsp70 exposed on the plasma membrane of tumor cells is part of the oligomerization domain. Therefore, a 14-mer peptide TPP (aa 450–463) covering this region selectively binds to mHsp70+ tumor cells and can also become internalized. Based on these findings, a fluorescence and radiolabeled TPP peptide tracer has been developed that specifically targets mHsp70+ tumors in vitro and in tumor mouse models [51,52]. More recent studies demonstrated a role of mHsp70 in the formation of cell-to-cell connections via tunneling nanotubes (TNTs) in a 100 nm range, employing live-cell STED nanoscopy [53]. TNTs originate from cholesterol-rich microdomains, where mHsp70 co-localizes with the tumor-specific glycosphingolipid globoyltriaoslyceramide Gb3/CD77 [54].
Gb3, predominantly found in cholesterol-rich microdomains (CRMs), is overexpressed on the surface of tumor cells, as compared to corresponding normal cells [54]. Among other effects, a depletion of cholesterol by methyl-β-cyclodextrin reduces the amount of Gb3 concomitant with the amount of mHsp70 from the plasma membrane of tumor cells. Furthermore, in vitro experiments employing artificial liposomes consisting of PC/SM/Chol/Gb3 at a ratio of 17/45/33/5 confirmed a specific interaction of recombinant Hsp70 specifically with Gb3-containing vesicles [54]. Presumably, the interaction of Gb3 with the ATPase domain of Hsp70 in CRMs resembles the association of Hsp70 with 3’-sulfogalactolipid (SGL) [55]. Employing the truncated and mutagenized polymerase chain reaction products of the N-terminal Hsp70 fragments (NBD) including residues 318–387 (the base of the ATP-binding cleft) has shown that particularly Arg (342) and Phe (198) are crucial for binding of SGL [55]. Furthermore, time-resolved high-resolution AFM images as well as mutational analysis have proven the interaction of NBD with lipids [33,36,42,56]. In the study of Mahalka et al., it was proposed that Hsp70 can directly bind to membranes via insertion into the bilayers by the tryptophan residues Trp-580 in the SBD and Trp-90 in NBD [56].
Upon hypoxia stress or mild heat shock, mHsp70 co-localizes with the non-raft lipid component phosphatidylserine (PS) on the surface of tumor cells [57,58]. Presumably, the translocation of Hsp70 from the cytosol to the outer leaflet could be assisted by flipping of PS from the inner to the outer leaflet, although further experiments for elucidating this mechanism are required. A direct interaction of recombinant Hsp70 with PS was proven in artificial unilamellar phosphatidylcholine/phosphatidylserine (PC/PS) liposomes at different PC/PS ratios ranging from physiological ratios of 8:2 to 2:8, in which the highest interaction was observed in liposomes with the highest PS content. Charge-dependent, non-specific interactions of Hsp70 with lipids could be excluded since Hsp70 did not incorporate into phosphatidylcholine/phosphatidylglycerol (PC/PG, ratio 8:2) liposomes with identical charge. An interaction of exogenously administered Hsp70 with mHsp70 of stressed tumor cells can also occur by a protein–protein interaction via the extracellular-localized oligomerization domain of Hsp70 although further experiments are required to prove this hypothesis [36,42]. The binding of exogenous Hsp70 to PS at high concentrations (10–50 µg/mL) resulted in a concentration-dependent reduction in tumor cell viability (EC50 of Hsp70 = 55 μg/mL) and proliferation, which in turn enhanced the radiosensitization of hypoxic cells [57]. Screening the PS moieties with annexin V decreased the toxic effects of Hsp70 or Hsc70 that were added into the culture medium [59]. Subsequent experiments employing atomic force microscopy (AFM) have proven an association of recombinant Hsp70 with planar lipid monolayers at a dipalmitoylphosphatidylcholine/dipalmitoylphosphatidylserine (DPPC/DPPS) ratio of 80:20 mol% [60]. Presumably, an electrostatic Hsp70 interaction with lipids is essential for the initial docking with the membrane and that anchoring is driven by the alignment of protein domains with the dipalmitoyl chains of DPPS [60,61]. Further in vitro experiments confirmed an association of Hsp70 with PS and Gb3 [62,63,64].
Apart from heat shock and hypoxia several other stress factors including γ-irradiation and UV light [65,66,67], anti-inflammatory agents [68], cytostatic drugs (e.g., taxol, vincristinsulfate) [69], membrane-interacting alkyl-lysophospolipids [70], and HDAC inhibitors (antibiotic depsipeptide FR901228) [71] result in an upregulation of cytosolic and mHsp70 on tumor cells. Furthermore, exogenously administered recombinant human Hsp70 induces the relocation of its cytosolic form to the plasma membrane after internalization, and thereby increases the level of mHsp70 [48].
Membrane-bound Hsp70 also plays an important role in tumor immunosurveillance, serving as an antigen for the adaptive and innate immune system [9,29,72]. Hsp70-chaperoned tumor peptides presented on the plasma membrane of tumor cells are recognized by αβ and γδ T-lymphocytes [73,74]. As shown by Wei et al., a subsequent incubation of target cells with anti-Hsp70 antibody abrogated the cytotoxicity of OK432 (streptococcal preparation)-activated γδ T-lymphocytes [73]. In line with these findings, autologous polymorphonuclear neutrophils (PMNs) expressing mHsp70 are recognized and lysed by γδ T-lymphocytes, and thereby protect the host cells from inflammation-induced damage [75]. Furthermore, cells undergoing apoptotic cell death show an upregulated mHsp70 expression in the context with PS. Macrophages recognize PS on the outer leaflet as an “eat-me” signal [76,77,78].
Further studies have demonstrated that mHsp70 on tumor cells, even in the absence of HSP-chaperoned peptides, can be recognized by natural killer (NK) cells, particularly after ex vivo stimulation with Hsp70 peptide TKD and low-dose IL-2 [72,79,80]. Subsequent antibody blocking experiments suggest that the heterodimeric C-type lectin receptor CD94 in complex with NKG2C on NK cells serves as a potential receptor for mHsp70. A co-incubation of NK cells with TKD/IL-2 resulted in significant upregulation of the CD94 density on NK cells that was accompanied by an increased cytolytic activity mediated by an upregulated granzyme B production [81] against mHsp70+ tumor cells [82,83]. Preclinical studies employing human pancreatic (Colo357) and colon (CX2) carcinoma-bearing SCID/beige mice after intravenous injection of ex vivo TKD/IL-2-stimulated human NK cells have further proven the therapeutic potency of NK cells with respect to tumor growth control and reduction in liver metastasis [84,85]. Vice versa, the importance of mHsp70 for eliciting NK cell-based anti-tumor activity was demonstrated after treatment of tumor cells with vitamin A derivates, such as 13-cis retinoic acid (13-RA) or all-trans retinoic acid (ATRA), which are known to support redifferentiation of tumor towards normal cells concomitant with a loss in the mHsp70 expression [86]. A long-term co-incubation of tumor cells with these agents at non-toxic concentrations resulted in a significant decrease in the mHsp70 expression density, which in turn reduced the sensitivity of these redifferentiated cells to the cytolytic activity of NK cells [86].
In a phase I clinical trial, the safety, tolerability and feasibility of ex vivo TKD/IL-2-stimulated autologous NK cells were proven in 12 patients with advanced tumor stages (colorectal cancer, n = 11; NSCLC, n = 1) [87]. Based on these promising clinical data, a randomized multicenter phase II clinical trial (EudraCT 2008-002130-30) was started in patients with non-metastasized but locally advanced (IIIA and IIIB) NSCLC in combination with radiochemotherapy [88].
An interesting approach to restore tumor cell sensitivity towards cytolytic activity of NK cells was introduced by Sapozhnikov et al., employing the barnase:barstar pair for a targeted delivery of full-length Hsp70 or the 16 kDa C-terminal Hsp70 fragment to the plasma membrane [89]. In the first module, anti-HER2/neu mini-antibody conjugated with barnase was applied for a selective binding to the cell membrane of SKOV3 human ovarian adenocarcinoma and human BT-474 breast carcinoma cells. In a second step, the module barstar-Hsp70 (or its 16 kDa fragment) was attached to the first module, subsequently stimulating cytotoxic activity of NK cells against cancer cells, in vitro [89].
mHsp70 could be employed for the development of novel diagnostic and therapeutic (i.e., theranostic) Hsp70-targeting agents and could serve as a biomarker for detection and monitoring of tumors [90] or virally infected cells. Up-to-date radionuclide-, fluorescence-, nanoparticle-labeled mHsp70-targeted tools (including full recombinant Hsp70, monoclonal anti-Hsp70 antibodies, antibody Fab fragments, tumor penetrating peptide (TPP), granzyme B, and anticalines) have been successfully employed for visualization (MRI, PET, epifluorescence) and therapy in preclinical studies (Table 1). Thus, several studies demonstrated that mHsp70-targeted nanoparticles could be used for the detection and therapy of tumors [50,51,52,67,91]. In a recent study, functionalized nanoparticles with the serine protease granzyme B (GrB) (GrB-SPIONs) were used as a negative contrast enhancement agent for visualization of tumors by magnetic resonance imaging (MRI) and a pro-apoptotic therapeutic agent [91].
Another member of the HSP70 family, the ER-localized glucose-regulated protein 78 (GRP78), was also reported to be expressed on the membrane of tumor cells [10,92,93,94,95]. Due to the four hydrophobic domains capable of forming transmembrane helices localizing both the C- and N-terminal domains outside the membrane, GRP78 is expressed as a transmembrane protein [95]. In a recent study by Vig et al., it was demonstrated that GRP78 translocated to the membrane via the anterograde secretory pathway through Golgi complex, and DNAJC3 protein facilitated this process [96]. Membrane-bound GRP78 acts as a signaling receptor that, upon binding of its extracellular form sGRP78, initiated pro-apoptotic signaling cascades (increasing caspase 3/7 activity), which was accompanied by enhanced Bax and Chop mRNA expression [96]. Further studies have shown that GRP78 can also regulate the PI3K/Akt signaling [97,98]. Apart from direct embedding into the lipid bilayer, GRP78 can directly bind to transmembrane protein complexes and thereby interact with membranes [99].
Membrane-associated GRP78 was reported for hepatocellular carcinoma [100], prostate cancer [101,102], mammary carcinoma [103,104], lung [105,106] and gastric cancers [107,108].
mGRP78 has been shown to serve as a potential target for tumor-specific therapies (Table 1) [109]. Subsequent studies by Rauschert et al. demonstrated that apart from mGRP78 expressed on the cell membrane, its post-transcriptionally modified 82 kDa glycosylated isoform, termed GRP78SAM-6, is exposed particularly on the plasma membrane of a wide range of cancer types, but not on normal cells [109].
As reported by Papalas et al., expression of GRP78 in melanoma patients correlated with patient survival and invasive potential of the tumor [110]. Previously, it was demonstrated that GRP78 serves as a signaling receptor for activated α2-macroglubulin, microplasminogen, and plasminogen kringle 5, which functions as a receptor for angiogenic peptides. Furthermore, GRP78 is also involved in the MHC class I antigen presentation cascade [111,112]. Thus, binding of α2-macroglubulin to mGRP78 induces mitogenic signaling and tumor cell proliferation and increases metastatic spread [113,114]. Furthermore, it plays an important role for viral entry of dengue fever and coxsackie B virus. Subsequent studies by Arap et al. demonstrated that synthetic chimeric peptides designed from GRP78 binding motifs (i.e., WIFPWIQL and WDLAWMFRLPVG), fused to the programmed cell death-inducing sequence, can decrease tumor progression in preclinical models of breast and prostate cancer [115]. Application of monoclonal antibodies directed against the COOH-terminal domain of GRP78 also shows a pro-apoptotic activity (via upregulation of p53) in 1-LN and DY145 prostate cancer cells and A375 melanoma cells [116]. However, mGRP78 association was also reported for normal cells including macrophages, fibroblasts and endothelial cells, indicating possible off-target effects induced by anti-GRP78 therapies [112,117,118,119]. Indeed, in the study by Katanasaka et al., the authors demonstrated that GRP78-targeted WIFPWIQL-modified liposomes containing doxorubicin, efficiently bound to colon carcinoma cells and HUVEC endothelial cells [117]. To reduce unfavorable side effects of anti-GRP78 antibodies, a human monoclonal IgM antibody (SAM-6) derived from a gastric cancer patient was tested which is recognizing a cancer-specific GRP78–O-linked carbohydrate moiety [109]. Application of the SAM-6 IgM antibody resulted in a tumor-specific cell death via lipoptosis [120,121].

3. HSP90 Family

For the HSPC (HSP90) family, a membrane association was reported for two representatives: (1) Hsp90 (isoforms Hsp90α and Hsp90β), and (2) ER resident GRP96 (Figure 1, Table 2). In a study by Zhang et al. using surface plasmon resonance (SPR), it was shown that Hsp90 interacts with unsaturated phospholipids (i.e., POPS and POPG), and the observed affinity was higher when negatively charged lipids were involved (as compared to the zwitterionic lipids) [132]. Upon interaction with lipids, the α-helical structure of Hsp90 was increased, which may play a role for protein docking in the membrane. Addition of cholesterol to the lipid vesicles further enhanced the binding capacity of Hsp90. However, above a certain level of cholesterol (up to 50% of lipid composition) the association of Hsp90 was abrogated [132]. Presumably, localization of Hsp90 in the plasma membrane could increase its rigidity and integrity, which in turn protects cancer cells from various stress factors (including thermal stress) [132,133]. Indeed, for other HSPs (e.g., Hsp17), an association with the membrane resulted in a stabilization of the bilayer and a reduction in the membrane fluidity, thus providing thermotolerance and restoration of membrane functionality [11,12,134,135,136]. In a recent study by Li et al., it was demonstrated that Hsp90AA1 interacts with membrane phospholipids at high affinities not only via electrostatic interactions, but also by embedding its C-terminus into the bilipid layer which is accompanied with a conformational change of the protein (as shown by far-UV circular dichroism) [137]. Insertion of full-length Hsp90AA1 or its truncated form (Hsp90AA1-CTD) into membranes improved membrane integrity and induced thermotolerance in Escherichia coli (E. coli) [137]. A similar stabilizing role upon interaction with membrane phospholipids was described for Hsp90B1 from Anas platyrhnchos (ApHsp90B1) [138]. Apart from the C-terminus, the conserved amphipathic helix of Hsp90 was also found to play a role in the interaction of Hsp90 with membranes, and thereby promotes its exosomal release [139].
In addition to interactions with phospholipids, Hsp90 also has been found to be associated with lipid rafts in membranes [140]. Thus, the depletion of cholesterol results in the dissociation of Hsp70 and Hsp90 from lipid rafts [140].
An association of Hsp90 with the plasma membrane was shown for melanoma metastasis, but not for melanocytic lesions [141]. Additionally, mHsp90 upregulation, particularly the inducible isoform Hsp90α but not Hsp90β, on tumor cells was reported for fibrosarcoma HT-1080 and MDA-MB231 triple negative breast adenocarcinoma cells [16]. Hsp90α interacted with matrix metalloproteinase 2 (MMP2) in the extracellular space. Subsequent inhibition of Hsp90α employing anti-Hsp90 antibodies or scFvs significantly inhibited tumor cell invasion [16]. However, in another study employing HT-1080 and human A172 glioblastoma cells, the authors indicated that both Hsp90 isoforms, Hsp90α and Hsp90β, play a role for the motility of tumor cells. The cell surface heparan sulfate proteoglycans have been shown to play a role for the membrane expression of Hsp90 [142]. A decrease in sulfonation of heparan sulfates by heparinase I/III or heparin reduces the levels of both isoforms and subsequently inhibited cell motility [143]. An involvement of mHsp90 for tumor cell motility was further proven by small-molecule DMAG-N-oxide, a cell-impermeable 17DMAG-derived Hsp90 inhibitor [143]. The anti-invasive and anti-migratory activities of DMAG-N-oxide were demonstrated for different tumor cells types such as T24 bladder cancer, PC3M prostate cancer, and B16 melanoma cells in vitro at μM levels. Precise analysis revealed that mHsp90 might be involved in integrin signaling, which in turn influences focal adhesion. Subsequent in vivo studies showed that application of either DMAG-N-oxide or anti-Hsp90 antibody SPA830 reduced lung colonization after i.v. injection of B16 melanoma cells [143]. Employment of another monoclonal antibody 4C5 also reduced B16F10 melanoma metastasis in mice [144]. Furthermore, GA conjugated to cell-impermeable agarose beads could inhibit cell migration [16]. In the study by Cid et al., expression of mHsp90 was shown for the human neuroblastoma cells NB69 [145]. Furthermore, upregulation of mHsp90 was higher in undifferentiated spherical neuroblastoma cells as compared to more differentiated flattened cells [145]. Expression of mHsp90 was also shown to be important for the migration of neuronal cells, thus indicating a role of the protein in the development of the nervous system [146]. Additionally, it was reported that mononuclear cells obtained from patients with systemic lupus erythematosus also express mHsp90 [147]. Intriguingly, as shown by Li et al., extracellular Hsp90α can also regulate human fibroblast cell motility via the HIF-1 pathway and thereby influences wound healing in mice [148].
Another protein Grp96, the ER homologue of Hsp90, was shown to be associated with the plasma membrane and plays a role in the induction of immune responses [17]. mGrp96 expression was reported to be associated with tumor malignancy in certain tumor types [17,149,150]. mGrp96 can bind to the metalloproteinase domain with thrombospondin type 1 motifs 9 (pro-ADAMTS9), and a metalloprotease pro-a disintegrin-like domain that results in enhanced tumor progression and angiogenesis [151,152,153]. Intriguingly, various infections including E. coli K1 and Listeria monocytogenes also upregulated the expression of mGrp96 [154,155,156]. Furthermore, mGrp96 expression was reported for murine immature thymocytes [157]. In a study by Hou et al., it was shown that mGrp96-targeted siRNA could significantly inhibit tumor growth and increase the overall survival of animals [158]. mGrp96 was shown to interact with HER2, thus facilitating the HER2 dimerization, with subsequent promotion of tumor cell proliferation. Inhibition of conformational Grp96 changes by an α-helix peptide decreases the HER2 dimerization, with subsequent inhibition of tumor cell growth, in vitro and in vivo [159]. Inhibition of mGrp96 by using anti-Grp96 monoclonal antibodies induces apoptosis and decreases tumor growth, in vivo [160].

4. Other Membrane-Associated HSPs

Among other HSPs, Hsp25 (murine homolog of human Hsp27) is known to be present on the plasma membrane of tumor cells (Figure 1) [161]. Previous studies demonstrated that large parts (particularly α-crystallin domain) of HSPB1 (Hsp27) and HSPB5 (αB-crystallin) are embedded in liposomes that contain a variety of phospholipids (i.e., POPS, POPC, and POPG) [162,163,164,165,166]. As shown by Bausero et al., high mHsp25 expression on 4T1 mammary carcinoma cells was associated with tumor progression and an increased metastatic spread into the lung in an o.t. mouse model [167]. Another member of the small heat shock protein family, Hsp22/HspB8, was shown to be expressed on the surface of human neuroblastoma SK-N-SH cells [168]. Subsequent in vitro studies, employing lipid vesicles containing phosphatidic acid, phosphatidylinositol or phosphatidylserine, demonstrated an association of Hsp22 with these lipids, which results in a conformational change of Hsp22 [168].
Hsp60 plasma membrane localization was shown for Daudi cells [169]. Application of two antibodies (N-20 and K-19) directed towards the amino- and carboxyl-terminus of mHsp60 revealed the presence of the full-length protein on the cell surface [169]. In another study, the authors demonstrated that mHsp60, like Hsp70, is associated with lipid rafts as well as with Golgi apparatus and exosomes [170]. Presumably, various stress-inducing factors could stimulate the expression of mHsp60. Indeed, in the study by Pfister et al., it was shown that upon heat shock, HUVECs start to present mHsp60 [171]. Subsequent atomic force microscopy (AFM) employing monoclonal antibody AbII-13 tethered to AFM tips confirmed the association of mHsp60 with plasma membrane in a patchy distribution pattern [171]. Another stress (i.e., acute injury) to the cardiac myocytes could also induce the expression of mHsp60 [172,173]. Presumably, mHsp60 plays a role in the activation of immune responses. Liver cells infected with intracellular bacterium Listeria monocytogenes exhibited high levels of mHsp60 [174]. Intriguingly, kinetic profiling of γδ T cell responses most closely matched that of mHsp60 expression in liver and tumors [175]. Further studies employing secondary human enterocyte-like Caco-2 cells demonstrated that heat shock (41 °C), TNFα, or L. monocytogenes infections (104–106 CFU/mL) increased the expression of mHsp60 and, as a result, enhances cell adhesion, but not invasion [175]. Subsequent application of shRNA reversed the adhesive properties of the cells.
Calreticulin, another ER-residing stress protein present on tumor cell membranes, was shown to induce migratory capacity in melanoma cells [18]. Application of anti-calreticulin antibodies significantly reduced laminin-dependent spreading of melanoma cells. As shown by Elton et al., calreticulin interacts with collagen receptors integrin α2β1 and glycoprotein VI in human platelets that could further support the hypothesis of calreticulin involvement in tumor cell spreading [176]. Calreticulin can bind in a Ca2+-dependent manner to phosphatidylserine (PS) with high affinity (KD = 1.5 × 10−5 M) [177,178]. Further studies demonstrated that calreticulin can be associated with lipid rafts in connection with ERP57 [179,180]. Thus, knockdown of ERP57 reduced the expression of calreticulin on the cell surface and subsequently reduces the phagocytic capacity of dendritic cells, which in turn decreases immunogenicity, in vivo [180].
Hsp40 (Hdj1) was shown to be associated with Hsp70 on the surface of CX+ colon and Colo+ pancreatic carcinoma cells [15]. Previously, it was shown that Hsp40 is secreted from cells via the Hsp/Hsc70-dependent exosome pathway [181]. Presumably interaction of the J-domain of Hsp40 with Hsp70 could explain the co-localization of the two proteins on the membrane. Other studies confirmed the expression of Hsp47 on scirrhous carcinoma of stomach and cervical carcinoma [182,183]. mHsp70+/mHsp40+ tumor cells demonstrated a high radioresistance [15]. However, as shown by Hebert et al., high levels of mHsp47 on the epidermoid carcinoma cell lines were associated with a low invasive capacity [184]. In contrast to other data, Yamamoto et al. showed that downregulation of Hsp47 by microRNA-29a (miR-29a) inhibited tumor cell migration and invasion in cervical squamous cell carcinoma [183].
Large parts of sHSPs (particularly α-crystallin domain) are embedded into lipid bilayers (a) or they can be present on the cell surface (b) [162,163,164,165,166,167]. Calreticulin was described to be associated with phosphatidylserine (a) or with lipid rafts (b) [18,176,177,178,179,180]. For Hsp60, the presence of full-length protein on the cell membrane (a) or in association with lipid rafts (b) was reported [169,170]. Hsp70 was shown to be embedded via its NBD in the outer layer of membranes (a), associated with the membrane surface (b) (presumably in close interaction with the J-domain of Hsp40 protein), and associated with glycosphingolipid Gb3/CD77 in cholesterol-rich microdomains (CRMs) (c) [33,36,54,56,57,58,59,60,61,62,63,64]. The ER-localized glucose-regulated protein 70 (GRP78) was shown to be present on the membrane surface (a) (including association with transmembrane protein complex, surface glycosylphosphatidylinositol-anchored proteins) or embedded into the lipid bilayer (b) [95,99]. Hsp90 was demonstrated to be present on the membrane surface (a), embedded into the membrane via its C-terminus (b) or can be associated with lipid rafts (c) [137,138,140]. Grp96, a homologue of Hsp90, was shown to be expressed on the membrane surface [17,149,150].

5. Conclusions

Apart from their important intracellular functions as molecular chaperones in regulating intracellular proteostasis, many HSPs have been shown to be expressed on the surface of various types of solid and hematological malignancies. An increased expression density of mHSPs is associated with tumor progression, resistance to anti-tumor therapies (e.g., radiochemotherapy), and an enhanced invasive and metastatic potential. Certain membrane-bound HSPs, including mHsp60, mHsp70 and their endoplasmatic analogues mGRP78, mGRP96, and membrane calreticulin, were demonstrated to induce innate and adaptive anti-cancer immunity. Exposure of the intracellular endoplasmatic chaperones on the plasma membrane of tumor and, in some cases, damaged normal cells, followed by subsequent activation of immunity represents a possible mechanism of immunologic surveillance for elimination of malignantly transformed or damaged cells. Some membrane-bound chaperones (e.g., Hsp70 and Hsp90) could also play a role in tumor cell association with extracellular matrices, thus influencing cell motility and invasion. Exposure of HSPs on the membrane is directly related to the composition of the lipid bilayer. Presumably, pharmacological modulation and/or modification of membrane lipid structures and microdomains could be further exploited in regards to chaperone expression, which in turn could be used for cancer therapies [185,186,187,188]. Expression of HSPs on malignant cells makes them a promising target for development of novel diagnostic and therapeutic approaches in oncology. Several preclinical and clinical studies listed in this review demonstrated their therapeutic activity in targeted therapies directed against membrane-bound HSPs.

Author Contributions

The review paper was conceived and designed by M.S., Z.B., W.K., H.G., L.V., and G.M. All authors wrote the manuscript. All authors have read and agreed to the published version of the manuscript.

Funding

This study was supported by the Alexander von Humboldt Fellowship, a grant from the Russian Foundation for Basic Research № 19-58-55001, a grant from the Deutsche Forschungsgemeinschaft (DFG SFB824/3), BMBF (01GU0823, 02NUK038A), BMWi (AiF project), Germany, and the Technische Universität München (TUM) within the DFG funding programme Open Access Publishing. Zsolt Balogi was funded by UP MS KA-2018-05. Huile Gao was funded by National Natural Science Foundation of China (81961138009).László Vígh was funded by the GINOP-2.3.2-15-2016-00060 grant.

Acknowledgments

The authors are grateful to Nan-Jong Lee for figure preparation.

Conflicts of Interest

The authors declare no conflict of interest. The funders had no role in the design of the study; in the writing of the manuscript, or in the decision to publish the results.

Abbreviations

ADPadenosine diphosphate
AFMatomic force microscopy
Aktprotein kinase B
ATPadenosine triphosphate
BFAbrefeldin A
BiPbinding immunoglobulin protein
CRMcholesterol-rich microdomain
DMAGdesmethoxy-17-N,N-dimethylaminoethylaminogeldanamycin
DNAJC3DNAJ homolog subfamily C member 3
DPPCdipalmitoylphosphatidylcholine
DPPSdipalmitoylphosphatidylserine
ERendoplasmatic reticulum
ERP57endoplasmic reticulum (ER)-resident protein 57
GRP78glucose regulated protein 78
GRP96glucose regulated protein 96
HDAChistone deacetylase
HIF-1αhypoxia-inducible factor 1-alpha
HNSCChead and neck squamous cell carcinoma
HopHsp70-Hsp90 organizing protein
HSFheat shock factor
HSPheat shock proteins
HSP2727 kDa heat shock proteins
HSP4040 kDa heat shock proteins
HSP6060 kDa heat shock proteins
HSP7070 kDa heat shock proteins
HSP9090 kDa heat shock proteins
IL-2interleukin 2
MHCmajor histocompatibility complex
mHsp70membrane-bound Hsp70
MRImagnetic resonance imaging
MMP2matrix metalloproteinase 2
NBDnucleotide binding domain
NK cellsnatural killer cells
NSCLCnon-small-cell lung carcinoma
PCphosphatidylcholine
PDIprotein disulfide-isomerase
PETpositron emission tomography
PI3Kphosphatidylinositol 3-kinase
PMNspolymorphonuclear neutrophils
POPC1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine
POPG1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol
POPS1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-L-serine
PSphosphatidylserine
SBDsubstrate-binding domain
SGL3’-sulfogalactolipid
SPIONssuperparamagnetic iron oxide nanoparticles
SPRsurface plasmon resonance
STEDstimulated emission depletion microscopy
TPPtumor-penetrating peptide

References

  1. Kampinga, H.H.; Hageman, J.; Vos, M.J.; Kubota, H.; Tanguay, R.M.; Bruford, E.A.; Cheetham, M.E.; Chen, B.; Hightower, L.E. Guidelines for the nomenclature of the human heat shock proteins. Cell Stress Chaperones 2009, 14, 105–111. [Google Scholar] [CrossRef] [Green Version]
  2. Hartl, F.U.; Hayer-Hartl, M. Molecular chaperones in the cytosol: From nascent chain to folded protein. Science 2002, 295, 1852–1858. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  3. Schmitt, E.; Gehrmann, M.; Brunet, M.; Multhoff, G.; Garrido, C. Intracellular and extracellular functions of heat shock proteins: Repercussions in cancer therapy. J. Leukoc. Biol. 2007, 81, 15–27. [Google Scholar] [CrossRef] [PubMed]
  4. Calderwood, S.K.; Khaleque, M.A.; Sawyer, D.B.; Ciocca, D.R. Heat shock proteins in cancer: Chaperones of tumorigenesis. Trends Biochem. Sci. 2006, 31, 164–172. [Google Scholar] [CrossRef] [PubMed]
  5. Velazquez, J.M.; Lindquist, S. Hsp70: Nuclear concentration during environmental stress and cytoplasmic storage during recovery. Cell 1984, 36, 655–662. [Google Scholar] [CrossRef]
  6. Knowlton, A.A.; Grenier, M.; Kirchhoff, S.R.; Salfity, M. Phosphorylation at tyrosine-524 influences nuclear accumulation of HSP72 with heat stress. Am. J. Physiol. Heart Circ. Physiol. 2000, 278, 2143–2149. [Google Scholar] [CrossRef]
  7. Kodiha, M.; Chu, A.; Lazrak, O.; Stochaj, U. Stress inhibits nucleocytoplasmic shuttling of heat shock protein hsc70. Am. J. Physiol. Cell Physiol. 2005, 289, 1034–1041. [Google Scholar] [CrossRef] [Green Version]
  8. Multhoff, G.; Botzler, C.; Wiesnet, M.; Eissner, G.; Issels, R. CD3-large granular lymphocytes recognize a heat-inducible immunogenic determinant associated with the 72-kD heat shock protein on human sarcoma cells. Blood 1995, 86, 1374–1382. [Google Scholar] [CrossRef] [Green Version]
  9. Shevtsov, M.; Multhoff, G. Heat Shock Protein-Peptide and HSP-Based Immunotherapies for the Treatment of Cancer. Front Immunol. 2016, 7, 171. [Google Scholar] [CrossRef] [Green Version]
  10. Shin, B.K.; Wang, H.; Yim, A.M.; Le Naour, F.; Brichory, F.; Jang, J.H.; Zhao, R.; Puravs, E.; Tra, J.; Michael, C.W.; et al. Global profiling of the cell surface proteome of cancer cells uncovers an abundance of proteins with chaperone function. J. Biol. Chem. 2003, 278, 7607–7616. [Google Scholar] [CrossRef] [Green Version]
  11. Török, Z.; Horváth, I.; Goloubinoff, P.; Kovács, E.; Glatz, A.; Balogh, G.; Vígh, L. Evidence for a lipochaperonin: Association of active protein-folding GroESL oligomers with lipids can stabilize membranes under heat shock conditions. Proc. Natl. Acad. Sci. USA 1997, 94, 2192–2197. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  12. Tsvetkova, N.M.; Horváth, I.; Török, Z.; Wolkers, W.F.; Balogi, Z.; Shigapova, N.; Crowe, L.M.; Tablin, F.; Vierling, E.; Crowe, J.H.; et al. Small heat-shock proteins regulate membrane lipid polymorphism. Proc. Natl. Acad. Sci. USA 2002, 99, 13504–13509. [Google Scholar] [CrossRef] [Green Version]
  13. Horváth, I.; Multhoff, G.; Sonnleitner, A.; Vígh, L. Membrane-associated stress proteins: More than simply chaperones. Biochim. Biophys. Acta 2008, 1778, 1653–1664. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  14. Balogi, Z.; Multhoff, G.; Jensen, T.K.; Lloyd-Evans, E.; Yamashima, T.; Jäättelä, M.; Harwood, J.L.; Vígh, L. Hsp70 interactions with membrane lipids regulate cellular functions in health and disease. Prog. Lipid Res. 2019, 74, 18–30. [Google Scholar] [CrossRef] [PubMed]
  15. Gehrmann, M.; Marienhagen, J.; Eichholtz-Wirth, H.; Fritz, E.; Ellwart, J.; Jäättelä, M.; Zilch, T.; Multhoff, G. Dual function of membrane-bound heat shock protein 70 (Hsp70), Bag-4, and Hsp40: Protection against radiation-induced effects and target structure for natural killer cells. Cell Death Differ. 2005, 12, 38–51. [Google Scholar] [CrossRef] [Green Version]
  16. Eustace, B.K.; Sakurai, T.; Stewart, J.K.; Yimlamai, D.; Unger, C.; Zehetmeier, C.; Lain, B.; Torella, C.; Henning, S.W.; Beste, G.; et al. Functional proteomic screens reveal an essential extracellular role for hsp90 alpha in cancer cell invasiveness. Nat. Cell Biol. 2004, 6, 507–514. [Google Scholar] [CrossRef]
  17. Altmeyer, A.; Maki, R.G.; Feldweg, A.M.; Heike, M.; Protopopov, V.P.; Masur, S.K.; Srivastava, P.K. Tumor-specific cell surface expression of the-KDEL containing, endoplasmic reticular heat shock protein gp96. Int. J. Cancer 1996, 69, 340–349. [Google Scholar] [CrossRef]
  18. White, T.K.; Zhu, Q.; Tanzer, M.L. Cell surface calreticulin is a putative mannoside lectin which triggers mouse melanoma cell spreading. J. Biol. Chem. 1995, 270, 15926–15929. [Google Scholar] [CrossRef] [Green Version]
  19. Wiersma, V.R.; Michalak, M.; Abdullah, T.M.; Bremer, E.; Eggleton, P. Mechanisms of Translocation of ER Chaperones to the Cell Surface and Immunomodulatory Roles in Cancer and Autoimmunity. Front. Oncol. 2015, 5, 7. [Google Scholar] [CrossRef]
  20. Thorsteinsdottir, J.; Stangl, S.; Fu, P.; Guo, K.; Albrecht, V.; Eigenbrod, S.; Erl, J.; Gehrmann, M.; Tonn, J.C.; Multhoff, G.; et al. Overexpression of cytosolic, plasma membrane bound and extracellular heat shock protein 70 (Hsp70) in primary glioblastomas. J. Neurooncol. 2017, 135, 443–452. [Google Scholar] [CrossRef]
  21. Breuninger, S.; Stangl, S.; Werner, C.; Sievert, W.; Lobinger, D.; Foulds, G.A.; Wagner, S.; Pickhard, A.; Piontek, G.; Kokowski, K.; et al. Membrane Hsp70-A Novel Target for the Isolation of Circulating Tumor Cells After Epithelial-to-Mesenchymal Transition. Front. Oncol. 2018, 8, 497. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  22. Stangl, S.; Tontcheva, N.; Sievert, W.; Shevtsov, M.; Niu, M.; Schmid, T.E.; Pigorsch, S.; Combs, S.E.; Haller, B.; Balermpas, P.; et al. Heat shock protein 70 and tumor-infiltrating NK cells as prognostic indicators for patients with squamous cell carcinoma of the head and neck after radiochemotherapy: A multicentre retrospective study of the German Cancer Consortium Radiation Oncology Group (DKTK-ROG). Int. J. Cancer 2018, 142, 1911–1925. [Google Scholar] [PubMed] [Green Version]
  23. Kaur, J.; Das, S.N.; Srivastava, A.; Ralhan, R. Cell surface expression of 70 kDa heat shock protein in human oral dysplasia and squamous cell carcinoma: Correlation with clinicopathological features. Oral Oncol. 1998, 34, 93–98. [Google Scholar] [CrossRef]
  24. Pfister, K.; Radons, J.; Busch, R.; Tidball, J.G.; Pfeifer, M.; Freitag, L.; Feldmann, H.J.; Milani, V.; Issels, R.; Multhoff, G. Patient survival by Hsp70 membrane phenotype: Association with different routes of metastasis. Cancer 2007, 110, 926–935. [Google Scholar] [CrossRef] [PubMed]
  25. Hantschel, M.; Pfister, K.; Jordan, A.; Scholz, R.; Andreesen, R.; Schmitz, G.; Schmetzer, H.; Hiddemann, W.; Multhoff, G. Hsp70 plasma membrane expression on primary tumor biopsy material and bone marrow of leukemic patients. Cell Stress Chaperones 2000, 5, 438–442. [Google Scholar] [CrossRef] [Green Version]
  26. Uozaki, H.; Ishida, T.; Kakiuchi, C.; Horiuchi, H.; Gotoh, T.; Iijima, T.; Imamura, T.; Machinami, R. Expression of heat shock proteins in osteosarcoma and its relationship to prognosis. Pathol. Res. Pract. 2000, 196, 665–673. [Google Scholar] [CrossRef]
  27. Steiner, K.; Graf, M.; Hecht, K.; Reif, S.; Rossbacher, L.; Pfister, K.; Kolb, H.J.; Schmetzer, H.M.; Multhoff, G. High HSP70-membrane expression on leukemic cells from patients with acute myeloid leukemia is associated with a worse prognosis. Leukemia 2006, 20, 2076–2079. [Google Scholar] [CrossRef] [Green Version]
  28. Hightower, L.E.; Guidon, P.T., Jr. Selective release from cultured mammalian cells of heat-shock (stress) proteins that resemble glia-axon transfer proteins. J. Cell Physiol. 1989, 138, 257–266. [Google Scholar] [CrossRef]
  29. Juhász, K.; Thuenauer, R.; Spachinger, A.; Duda, E.; Horváth, I.; Vígh, L.; Sonnleitner, A.; Balogi, Z. Lysosomal rerouting of Hsp70 trafficking as a potential immune activating tool for targeting melanoma. Curr. Pharm. 2013, 19, 430–440. [Google Scholar] [CrossRef] [Green Version]
  30. Evdokimovskaya, Y.; Skarga, Y.; Vrublevskaya, V.; Morenkov, O. Secretion of the heat shock protein HSP70 and HSC70 by baby hamster kidney (BHK-21) cells. Cell Biol. Int. 2010, 34, 985–990. [Google Scholar] [CrossRef]
  31. Murakami, N.; Kühnel, A.; Schmid, T.E.; Ilicic, K.; Stangl, S.; Braun, I.S.; Gehrmann, M.; Molls, M.; Itami, J.; Multhoff, G. Role of membrane Hsp70 in radiation sensitivity of tumor cells. Radiat. Oncol. 2015, 10, 149. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  32. Petersen, N.H.; Kirkegaard, T.; Olsen, O.D.; Jäättelä, M. Connecting Hsp70, sphingolipid metabolism and lysosomal stability. Cell Cycle 2010, 9, 2305–2309. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  33. Kirkegaard, T.; Roth, A.G.; Petersen, N.H.T.; Mahalka, A.K.; Olsen, O.D.; Moilanen, I.; Zylicz, A.; Knudsen, J.; Sandhoff, K.; Arenz, C. Hsp70 stabilizes lysosomes and reverts Niemann-Pick disease-associated lysosomal pathology. Nature 2010, 463, 549–553. [Google Scholar] [CrossRef] [PubMed]
  34. Armijo, G.; Okerblom, J.; Cauvi, D.M.; Lopez, V.; Schlamadinger, D.E.; Kim, J.; Arispe, N.; De Maio, A. Interaction of heat shock protein 70 with membranes depends on the lipid environment. Cell Stress Chaperones 2014, 19, 877–886. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  35. Arispe, N.; De Maio, A. ATP and ADP modulate a cation channel formed by Hsc70 in acidic phospholipid membranes. J. Biol. Chem. 2000, 275, 30839–30843. [Google Scholar] [CrossRef] [Green Version]
  36. Nimmervoll, B.; Chtcheglova, L.A.; Juhasz, K.; Cremades, N.; Aprile, F.A.; Sonnleitner, A.; Hinterdorfer, P.; Vigh, L.; Preiner, J.; Balogi, Z. Cell surface localized Hsp70 is a cancer specific regulator of clathrin-independent endocytosis. FEBS Lett. 2015, 589, 2747–2753. [Google Scholar] [CrossRef] [Green Version]
  37. Morgner, N.; Schmidt, C.; Beilsten-Edmands, V.; Ebong, I.O.; Patel, N.A.; Clerico, E.M.; Kirschke, E.; Daturpalli, S.; Jackson, S.E.; Agard, D.; et al. Hsp70 forms antiparallel dimers stabilized by post-translational modifications to position clients for transfer to Hsp90. Cell Rep. 2015, 11, 759–769. [Google Scholar] [CrossRef] [Green Version]
  38. Wu, S.; Hong, L.; Wang, Y.; Yu, J.; Yang, J.; Yang, J.; Zhang, H.; Perrett, S. Kinetics of the conformational cycle of Hsp70 reveals the importance of the dynamic and heterogeneous nature of Hsp70 for its function. Proc. Natl. Acad. Sci. USA 2020, 117, 7814–7823. [Google Scholar] [CrossRef] [Green Version]
  39. Beltrao, P.; Albanèse, V.; Kenner, L.R.; Swaney, D.L.; Burlingame, A.; Villén, J.; Lim, W.A.; Fraser, J.S.; Frydman, J.; Krogan, N.J. Systematic functional prioritization of protein posttranslational modifications. Cell 2012, 150, 413–425. [Google Scholar] [CrossRef] [Green Version]
  40. Aprile, F.A.; Dhulesia, A.; Stengel, F.; Roodveldt, C.; Benesch, J.L.; Tortora, P.; Robinson, C.V.; Salvatella, X.; Dobson, C.M.; Cremades, N. Hsp70 oligomerization is mediated by an interaction between the interdomain linker and the substrate-binding domain. PLoS ONE 2013, 8, e67961. [Google Scholar] [CrossRef] [Green Version]
  41. Mayer, M.P.; Schröder, H.; Rüdiger, S.; Paal, K.; Laufen, T.; Bukau, B. Multistep mechanism of substrate binding determines chaperone activity of Hsp70. Nat. Struct. Biol. 2000, 7, 586–593. [Google Scholar] [PubMed]
  42. Fouchaq, B.; Benaroudj, N.; Ebel, C.; Ladjimi, M.M. Oligomerization of the 17-kDa peptide-binding domain of the molecular chaperone HSC70. Eur. J. Biochem. 1999, 259, 379–384. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  43. Kim, D.; Lee, Y.J.; Corry, P.M. Constitutive HSP70: Oligomerization and its dependence on ATP binding. J. Cell Physiol. 1992, 153, 353–361. [Google Scholar] [CrossRef] [PubMed]
  44. Shevtsov, M.A.; Shatik, S.V.; Tokarev, V.; Mostova, M.I.; Tiutin, L.A.; Bychkova, N.V.; Mikhrina, A.L.; Onokhin, K.V.; Meshalkina, D.A.; Romanova, I.V.; et al. Biodistribution of the recombinant heat shock protein rhHsp70 in intracranial C6 glioma models in Wistar rats and subcutaneos B16/F10 melanoma in C57BL/6 mice. Vopr. Onkol. 2013, 59, 78–83. [Google Scholar]
  45. Shevtsov, M.A.; Kharatrian, V.A.; Pozdniakov, A.V.; Romanova, I.V.; Guzhova, I.V.; Margulis, B.A. Chaperone therapy in the rat model of intracranial glioblastoma. Vopr. Onkol. 2012, 58, 653–657. [Google Scholar]
  46. Abkin, S.V.; Pankratova, K.M.; Komarova, E.Y.; Guzhova, I.V.; Margulis, B.A. Hsp70 chaperone-based gel composition as a novel immunotherapeutic anti-tumor tool. Cell Stress Chaperones 2013, 18, 391–396. [Google Scholar] [CrossRef] [Green Version]
  47. Shevtsov, M.A.; Pozdnyakov, A.V.; Mikhrina, A.L.; Yakovleva, L.Y.; Nikolaev, B.P.; Dobrodumov, A.V.; Komarova, E.Y.; Meshalkina, D.A.; Ischenko, A.M.; Pitkin, E.; et al. Effective immunotherapy of rat glioblastoma with prolonged intratumoral delivery of exogenous heat shock protein Hsp70. Int. J. Cancer 2014, 135, 2118–2128. [Google Scholar] [CrossRef]
  48. Shevtsov, M.A.; Komarova, E.Y.; Meshalkina, D.A.; Bychkova, N.V.; Aksenov, N.D.; Abkin, S.V.; Margulis, B.A.; Guzhova, I.V. Exogenously delivered heat shock protein 70 displaces its endogenous analogue and sensitizes cancer cells to lymphocytes-mediated cytotoxicity. Oncotarget 2014, 5, 3101–3114. [Google Scholar] [CrossRef] [Green Version]
  49. Abkin, S.V.; Ostroumova, O.S.; Komarova, E.Y.; Meshalkina, D.A.; Shevtsov, M.A.; Margulis, B.A.; Guzhova, I.V. Phloretin increases the anti-tumor efficacy of intratumorally delivered heat-shock protein 70 kDa (HSP70) in a murine model of melanoma. Cancer Immunol. Immunother. 2016, 65, 83–92. [Google Scholar] [CrossRef]
  50. Stangl, S.; Gehrmann, M.; Riegger, J.; Kuhs, K.; Riederer, I.; Sievert, W.; Hube, K.; Mocikat, R.; Dressel, R.; Kremmer, E.; et al. Targeting membrane heat-shock protein 70 (Hsp70) on tumors by cmHsp70.1 antibody. Proc. Natl. Acad. Sci. USA 2011, 108, 733–738. [Google Scholar] [CrossRef] [Green Version]
  51. Stangl, S.; Varga, J.; Freysoldt, B.; Trajkovic-Arsic, M.; Siveke, J.T.; Greten, F.R.; Ntziachristos, V.; Multhoff, G. Selective in vivo imaging of syngeneic, spontaneous, and xenograft tumors using a novel tumor cell-specific hsp70 peptide-based probe. Cancer Res. 2014, 74, 6903–6912. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  52. Stangl, S.; Tei, L.; De Rose, F.; Reder, S.; Martinelli, J.; Sievert, W.; Shevtsov, M.; Öllinger, R.; Rad, R.; Schwaiger, M.; et al. Preclinical Evaluation of the Hsp70 Peptide Tracer TPP-PEG(24)-DFO[(89)Zr] for Tumor-Specific PET/CT Imaging. Cancer Res. 2018, 78, 6268–6281. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  53. Reindl, J.; Shevtsov, M.; Dollinger, G.; Stangl, S.; Multhoff, G. Membrane Hsp70-supported cell-to-cell connections via tunneling nanotubes revealed by live-cell STED nanoscopy. Cell Stress Chaperones 2019, 24, 213–221. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  54. Gehrmann, M.; Liebisch, G.; Schmitz, G.; Anderson, R.; Steinem, C.; De Maio, A.; Pockley, G.; Multhoff, G. Tumor-specific Hsp70 plasma membrane localization is enabled by the glycosphingolipid Gb3. PLoS ONE 2008, 3, e1925. [Google Scholar] [CrossRef] [Green Version]
  55. Mamelak, D.; Lingwood, C. The ATPase domain of hsp70 possesses a unique binding specificity for 3′-sulfogalactolipids. J. Biol. Chem. 2001, 276, 449–456. [Google Scholar] [CrossRef] [Green Version]
  56. Mahalka, A.K.; Kirkegaard, T.; Jukola, L.T.I.; Jäättelä, M.; Kinnunen, P.K.J. Human heat shock protein 70 (Hsp70) as a peripheral membrane protein. Biochim. Biophys. Acta 2014, 1838, 1344–1361. [Google Scholar] [CrossRef] [Green Version]
  57. Schilling, D.; Gehrmann, M.; Steinem, C.; De Maio, A.; Pockley, A.G.; Abend, M.; Molls, M.; Multhoff, G. Binding of heat shock protein 70 to extracellular phosphatidylserine promotes killing of normoxic and hypoxic tumor cells. FASEB J. 2009, 23, 2467–2477. [Google Scholar] [CrossRef] [Green Version]
  58. Bilog, A.D.; Smulders, L.; Oliverio, R.; Labanieh, C.; Zapanta, J.; Stahelin, R.V.; Nikolaidis, N. Membrane Localization of HspA1A, a Stress Inducible 70-kDa Heat-Shock Protein, Depends on Its Interaction with Intracellular Phosphatidylserine. Biomolecules 2019, 9, 152. [Google Scholar] [CrossRef] [Green Version]
  59. Arispe, N.; Doh, M.; Simakova, O.; Kurganov, B.; De Maio, A. Hsc70 and Hsp70 interact with phosphatidylserine on the surface of PC12 cells resulting in a decrease of viability. FASEB J. 2004, 18, 1636–1645. [Google Scholar] [CrossRef] [Green Version]
  60. Lamprecht, C.; Gehrmann, M.; Madl, J.; Römer, W.; Multhoff, G.; Ebner, A. Molecular AFM imaging of Hsp70-1A association with dipalmitoyl phosphatidylserine reveals membrane blebbing in the presence of cholesterol. Cell Stress Chaperones 2018, 23, 673–683. [Google Scholar] [CrossRef]
  61. Resh, M.D. Fatty acylation of proteins: The long and the short of it. Prog. Lipid Res. 2016, 63, 120–131. [Google Scholar] [CrossRef]
  62. Sugawara, S.; Kawano, T.; Omoto, T.; Hosono, M.; Tatsuta, T.; Nitta, K. Binding of Silurus asotus lectin to Gb3 on Raji cells causes disappearance of membrane-bound form of HSP70. Biochim. Biophys. Acta 2009, 1790, 101–109. [Google Scholar] [CrossRef]
  63. McCallister, C.; Kdeiss, B.; Nikolaidis, N. Biochemical characterization of the interaction between HspA1A and phospholipids. Cell Stress Chaperones 2016, 21, 41–53. [Google Scholar] [CrossRef] [Green Version]
  64. Broquet, A.H.; Thomas, G.; Masliah, J.; Trugnan, G.; Bachelet, M. Expression of the molecular chaperone Hsp70 in detergent-resistant microdomains correlates with its membrane delivery and release. J. Biol. Chem. 2003, 278, 21601–21606. [Google Scholar] [CrossRef] [Green Version]
  65. Suzuki, K.; Watanabe, M. Augmented expression of HSP72 protein in normal human fibroblasts irradiated with ultraviolet light. Biochem. Biophys. Res. Commun. 1992, 186, 1257–1264. [Google Scholar] [CrossRef]
  66. Matsumoto, H.; Wang, X.; Ohnishi, T. Binding between wild-type p53 and hsp72 accumulated after UV and gamma-ray irradiation. Cancer Lett. 1995, 92, 127–133. [Google Scholar] [CrossRef]
  67. Shevtsov, M.A.; Nikolaev, B.P.; Ryzhov, V.A.; Yakovleva, L.Y.; Marchenko, Y.Y.; Parr, M.A.; Rolich, V.I.; Mikhrina, A.L.; Dobrodumov, A.V.; Pitkin, E.; et al. Ionizing radiation improves glioma-specific targeting of superparamagnetic iron oxide nanoparticles conjugated with cmHsp70.1 monoclonal antibodies (SPION-cmHsp70.1). Nanoscale 2015, 7, 20652–20664. [Google Scholar] [CrossRef] [PubMed]
  68. Gehrmann, M.; Brunner, M.; Pfister, K.; Reichle, A.; Kremmer, E.; Multhoff, G. Differential up-regulation of cytosolic and membrane-bound heat shock protein 70 in tumor cells by anti-inflammatory drugs. Clin. Cancer Res. 2004, 10, 3354–3364. [Google Scholar] [CrossRef] [Green Version]
  69. Gehrmann, M.; Pfister, K.; Hutzler, P.; Gastpar, R.; Margulis, B.; Multhoff, G. Effects of antineoplastic agents on cytoplasmic and membrane-bound heat shock protein 70 (Hsp70) levels. Biol. Chem. 2002, 383, 1715–1725. [Google Scholar] [CrossRef]
  70. Botzler, C.; Ellwart, J.; Gunther, W.; Eissner, G.; Multhoff, G. Synergistic effects of heat and ET-18-OCH3 on membrane expression of Hsp70 and lysis of leukemic K562 cells. Exp. Hematol. 1999, 27, 470–478. [Google Scholar] [CrossRef]
  71. Jensen, H.; Andresen, L.; Hansen, K.A.; Skov, S. Cell-surface expression of Hsp70 on hematopoietic cancer cells after inhibition of HDAC activity. J. Leukoc. Biol. 2009, 86, 923–932. [Google Scholar] [CrossRef] [PubMed]
  72. Multhoff, G.; Botzler, C.; Jennen, L.; Schmidt, J.; Ellwart, J.; Issels, R. Heat shock protein 72 on tumor cells: A recognition structure for natural killer cells. J. Immunol. 1997, 158, 4341–4350. [Google Scholar] [PubMed]
  73. Wei, Y.; Zhao, X.; Kariya, Y.; Fukata, H.; Teshigawara, K.; Uchida, A. Induction of autologous tumor killing by heat treatment of fresh human tumor cells: Involvement of gamma delta T cells and heat shock protein 70. Cancer Res. 1996, 56, 1104–1110. [Google Scholar] [PubMed]
  74. Ménoret, A.; Patry, Y.; Burg, C.; Le Pendu, J. Co-segregation of tumor immunogenicity with expression of inducible but not constitutive hsp70 in rat colon carcinomas. J. Immunol. 1995, 155, 740–747. [Google Scholar] [PubMed]
  75. Hirsh, M.I.; Hashiguchi, N.; Chen, Y.; Yip, L.; Junger, W.G. Surface expression of Hsp72 by LPS-stimulated neutrophils facilitates gammadelta T cell-mediated killing. Eur. J. Immunol. 2006, 36, 712–721. [Google Scholar] [CrossRef] [PubMed]
  76. Sapozhnikov, A.M.; Gusarova, G.A.; Ponomarev, E.D.; Telford, W.G. Translocation of cytoplasmic HSP70 onto the surface of EL-4 cells during apoptosis. Cell Prolif. 2002, 35, 193–206. [Google Scholar] [CrossRef]
  77. Ishiyama, T.; Koike, M.; Akimoto, Y.; Fukuchi, K.; Watanabe, K.; Yoshida, M.; Wakabayashi, Y.; Tsuruoka, N. Heat shock-enhanced T cell apoptosis with heat shock protein 70 on T cell surface in multicentric Castleman’s disease. Clin. Exp. Immunol. 1996, 106, 351–356. [Google Scholar] [CrossRef]
  78. Poccia, F.; Piselli, P.; Vendetti, S.; Bach, S.; Amendola, A.; Placido, R.; Colizzi, V. Heat-shock protein expression on the membrane of T cells undergoing apoptosis. Immunology 1996, 88, 6–12. [Google Scholar] [CrossRef]
  79. Multhoff, G.; Botzler, C.; Wiesnet, M.; Müller, E.; Meier, T.; Wilmanns, W.; Issels, R.D. A stress-inducible 72-kDa heat-shock protein (HSP72) is expressed on the surface of human tumor cells, but not on normal cells. Int. J. Cancer 1995, 61, 272–279. [Google Scholar] [CrossRef]
  80. Gehrmann, M.; Schmetzer, H.; Eissner, G.; Haferlach, T.; Hiddemann, W.; Multhoff, G. Membrane-bound heat shock protein 70 (Hsp70) in acute myeloid leukemia: A tumor specific recognition structure for the cytolytic activity of autologous NK cells. Haematologica 2003, 88, 474–476. [Google Scholar]
  81. Gehrmann, M.; Stangl, S.; Kirschner, A.; Foulds, G.A.; Sievert, W.; Doss, B.T.; Walch, A.; Pockley, A.G.; Multhoff, G. Immunotherapeutic targeting of membrane Hsp70-expressing tumors using recombinant human granzyme B. PLoS ONE 2012, 7, e41341. [Google Scholar] [CrossRef] [Green Version]
  82. Gross, C.; Schmidt-Wolf, I.G.; Nagaraj, S.; Gastpar, R.; Ellwart, J.; Kunz-Schughart, L.A.; Multhoff, G. Heat shock protein 70-reactivity is associated with increased cell surface density of CD94/CD56 on primary natural killer cells. Cell Stress Chaperones 2003, 8, 348–360. [Google Scholar] [CrossRef] [Green Version]
  83. Gross, C.; Hansch, D.; Gastpar, R.; Multhoff, G. Interaction of heat shock protein 70 peptide with NK cells involves the NK receptor CD94. Biol. Chem. 2003, 384, 267–279. [Google Scholar] [CrossRef] [PubMed]
  84. Stangl, S.; Wortmann, A.; Guertler, U.; Multhoff, G. Control of metastasized pancreatic carcinomas in SCID/beige mice with human IL-2/TKD-activated NK cells. J. Immunol. 2006, 176, 6270–6276. [Google Scholar] [CrossRef] [PubMed]
  85. Moser, C.; Schmidbauer, C.; Gurtler, U.; Gross, C.; Gehrmann, M.; Thonigs, G.; Pfister, K.; Multhoff, G. Inhibition of tumor growth in mice with severe combined immunodeficiency is mediated by heat shock protein 70 (Hsp70)-peptide-activated, CD94 positive natural killer cells. Cell Stress Chaperones 2002, 7, 365–373. [Google Scholar] [CrossRef]
  86. Gehrmann, M.; Schönberger, J.; Zilch, T.; Rossbacher, L.; Thonigs, G.; Eilles, C.; Multhoff, G. Retinoid- and sodium-butyrate-induced decrease in heat shock protein 70 membrane-positive tumor cells is associated with reduced sensitivity to natural killer cell lysis, growth delay, and altered growth morphology. Cell Stress Chaperones 2005, 10, 136–146. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  87. Krause, S.W.; Gastpar, R.; Andreesen, R.; Gross, C.; Ullrich, H.; Thonigs, G.; Pfister, K.; Multhoff, G. Treatment of colon and lung cancer patients with ex vivo heat shock protein 70-peptide-activated, autologous natural killer cells: A clinical phase I trial. Clin. Cancer Res. 2004, 10, 3699–3707. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  88. Specht, H.M.; Ahrens, N.; Blankenstein, C.; Duell, T.; Fietkau, R.; Gaipl, U.S.; Günther, C.; Gunther, S.; Habl, G.; Hautmann, H.; et al. Heat Shock Protein 70 (Hsp70) Peptide Activated Natural Killer (NK) Cells for the Treatment of Patients with Non-Small Cell Lung Cancer (NSCLC) after Radiochemotherapy (RCTx)—From Preclinical Studies to a Clinical Phase II Trial. Front. Immunol. 2015, 6, 162. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  89. Sapozhnikov, A.M.; Klinkova, A.V.; Shustova, O.A.; Grechikhina, M.V.; Kilyachus, M.S.; Stremovskiy, O.A.; Kovalenko, E.I.; Deyev, S.M. A Novel Approach to Anticancer Therapy: Molecular Modules Based on the Barnase:Barstar Pair for Targeted Delivery of HSP70 to Tumor Cells. Acta Nat. 2018, 10, 85–91. [Google Scholar] [CrossRef]
  90. Chanteloup, G.; Cordonnier, M.; Isambert, N.; Bertaut, A.; Marcion, G.; Garrido, C.; Gobbo, J. Membrane-bound exosomal HSP70 as a biomarker for detection and monitoring of malignant solid tumours: A pilot study. Pilot Feasibility Stud. 2020, 6, 35. [Google Scholar] [CrossRef] [Green Version]
  91. Shevtsov, M.; Stangl, S.; Nikolaev, B.; Yakovleva, L.; Marchenko, Y.; Tagaeva, R.; Sievert, W.; Pitkin, E.; Mazur, A.; Tolstoy, P.; et al. Granzyme B Functionalized Nanoparticles Targeting Membrane Hsp70-Positive Tumors for Multimodal Cancer Theranostics. Small 2019, 15, e1900205. [Google Scholar] [CrossRef] [PubMed]
  92. Li, J.; Lee, A.S. Stress induction of GRP78/BiP and its role in cancer. Curr. Mol. Med. 2006, 6, 45–54. [Google Scholar] [CrossRef] [PubMed]
  93. Lee, A.S.; Hendershot, L.M. ER stress and cancer. Cancer Biol. Ther. 2006, 5, 721–722. [Google Scholar] [CrossRef]
  94. Mintz, P.J.; Kim, J.; Do, K.A.; Wang, X.; Zinner, R.G.; Cristofanilli, M.; Arap, M.A.; Hong, W.K.; Troncoso, P.; Logothetis, C.J.; et al. Fingerprinting the circulating repertoire of antibodies from cancer patients. Nat. Biotechnol. 2003, 21, 57–63. [Google Scholar] [CrossRef]
  95. Zhang, Y.; Liu, R.; Ni, M.; Gill, P.; Lee, A.S. Cell surface relocalization of the endoplasmic reticulum chaperone and unfolded protein response regulator GRP78/BiP. J. Biol. Chem. 2010, 285, 15065–15075. [Google Scholar] [CrossRef] [Green Version]
  96. Vig, S.; Buitinga, M.; Rondas, D.; Crèvecoeur, I.; van Zandvoort, M.; Waelkens, E.; Eizirik, D.L.; Gysemans, C.; Baatsen, P.; Mathieu, C.; et al. Cytokine-induced translocation of GRP78 to the plasma membrane triggers a pro-apoptotic feedback loop in pancreatic beta cells. Cell Death Dis. 2019, 10, 309. [Google Scholar] [CrossRef]
  97. Bi, X.; Zhang, G.; Wang, X.; Nguyen, C.; May, H.I.; Li, X.; Al-Hashimi, A.A.; Austin, R.C.; Gillette, T.G.; Fu, G.; et al. Endoplasmic Reticulum Chaperone GRP78 Protects Heart From Ischemia/Reperfusion Injury Through Akt Activation. Circ. Res. 2018, 122, 1545–1554. [Google Scholar] [CrossRef]
  98. Zhang, Y.; Tseng, C.C.; Tsai, Y.L.; Fu, X.; Schiff, R.; Lee, A.S. Cancer cells resistant to therapy promote cell surface relocalization of GRP78 which complexes with PI3K and enhances PI(3,4,5)P3 production. PLoS ONE 2013, 8, e80071. [Google Scholar] [CrossRef]
  99. Tsai, Y.L.; Zhang, Y.; Tseng, C.C.; Stanciauskas, R.; Pinaud, F.; Lee, A.S. Characterization and mechanism of stress-induced translocation of 78-kilodalton glucose-regulated protein (GRP78) to the cell surface. J. Biol. Chem. 2015, 290, 8049–8064. [Google Scholar] [CrossRef] [Green Version]
  100. Lim, S.O.; Park, S.G.; Yoo, J.H.; Park, Y.M.; Kim, H.J.; Jang, K.T.; Cho, J.W.; Yoo, B.C.; Jung, G.H.; Park, C.K. Expression of heat shock proteins (HSP27, HSP60, HSP70, HSP90, GRP78, GRP94) in hepatitis B virus-related hepatocellular carcinomas and dysplastic nodules. World J. Gastroenterol. 2005, 11, 2072–2079. [Google Scholar] [CrossRef]
  101. Misra, U.K.; Gonzalez-Gronow, M.; Gawdi, G.; Hart, J.P.; Johnson, C.E.; Pizzo, S.V. The role of Grp 78 in alpha 2-macroglobulin-induced signal transduction. Evidence from RNA interference that the low density lipoprotein receptor-related protein is associated with, but not necessary for, GRP 78-mediated signal transduction. J. Biol. Chem. 2002, 277, 42082–42087. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  102. Pootrakul, L.; Datar, R.H.; Shi, S.R.; Cai, J.; Hawes, D.; Groshen, S.G.; Lee, A.S.; Cote, R.J. Expression of stress response protein Grp78 is associated with the development of castration-resistant prostate cancer. Clin. Cancer Res. 2006, 12, 5987–5993. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  103. Lee, E.; Nichols, P.; Spicer, D.; Groshen, S.; Mimi, C.Y.; Lee, A.S. GRP78 as a novel predictor of responsiveness to chemotherapy in breast cancer. Cancer Res. 2006, 66, 7849–7853. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  104. Gazit, G.; Lu, J.; Lee, A.S. Deregulation of GRP stress protein expression in human breast cancer cell lines. Breast Cancer Res. Treat. 1999, 54, 135–146. [Google Scholar] [CrossRef] [PubMed]
  105. Koomagi, R.; Mattern, J.; Volm, M. Glucose-related protein (GRP78) and its relationship to the drug-resistance proteins P170, GST-pi, LRP56 and angiogenesis in non-small cell lung carcinomas. AntiCancer Res. 1999, 19, 4333–4336. [Google Scholar] [PubMed]
  106. Uramoto, H.; Sugio, K.; Oyama, T.; Nakata, S.; Ono, K.; Yoshimastu, T.; Morita, M.; Yasumoto, K. Expression of endoplasmic reticulum molecular chaperone Grp78 in human lung cancer and its clinical significance. Lung Cancer 2005, 49, 55–62. [Google Scholar] [CrossRef] [PubMed]
  107. Song, M.S.; Park, Y.K.; Lee, J.H.; Park, K. Induction of glucose-regulated protein 78 by chronic hypoxia in human gastric tumor cells through a protein kinase C-epsilon/ERK/AP-1 signaling cascade. Cancer Res. 2001, 61, 8322–8330. [Google Scholar]
  108. Zhang, J.; Jiang, Y.; Jia, Z.; Li, Q.; Gong, W.; Wang, L.; Wei, D.; Yao, J.; Fang, S.; Xie, K. Association of elevated GRP78 expression with increased lymph node metastasis and poor prognosis in patients with gastric cancer. Clin. Exp. Metastasis 2006, 23, 401–410. [Google Scholar] [CrossRef]
  109. Rauschert, N.; Brändlein, S.; Holzinger, E.; Hensel, F.; Müller-Hermelink, H.K.; Vollmers, H.P. A new tumor-specific variant of GRP78 as target for antibody-based therapy. Lab. Investig. 2008, 88, 375–386. [Google Scholar] [CrossRef]
  110. Papalas, J.A.; Vollmer, R.T.; Gonzalez-Gronow, M.; Pizzo, S.V.; Burchette, J.; Youens, K.E.; Johnson, K.B.; Selim, M.A. Patterns of GRP78 and MTJ1 expression in primary cutaneous malignant melanoma. Mod. Pathol. 2010, 23, 134–143. [Google Scholar] [CrossRef] [Green Version]
  111. Triantafilou, M.; Fradelizi, D.; Triantafilou, K. Major histocompatibility class one molecule associates with glucose regulated protein (GRP) 78 on the cell surface. Hum. Immunol. 2001, 62, 764–770. [Google Scholar] [CrossRef]
  112. Gonzalez-Gronow, M.; Selim, M.A.; Papalas, J.; Pizzo, S.V. GRP78: A multifunctional receptor on the cell surface. Antioxid. Redox Signal. 2009, 11, 2299–2306. [Google Scholar] [CrossRef] [PubMed]
  113. Misra, U.K.; Gonzalez-Gronow, M.; Gawdi, G.; Pizzo, S.V. The role of MTJ-1 in cell surface translocation of GRP78, a receptor for alpha 2-macroglobulin-dependent signaling. J. Immunol. 2005, 174, 2092–2097. [Google Scholar] [CrossRef] [Green Version]
  114. Misra, U.K.; Deedwania, R.; Pizzo, S.V. Activation and cross-talk between Akt, NF-kappaB, and unfolded protein response signaling in 1-LN prostate cancer cells consequent to ligation of cell surface-associated GRP78. J. Biol. Chem. 2006, 281, 13694–13707. [Google Scholar] [CrossRef] [Green Version]
  115. Arap, M.A.; Lahdenranta, J.; Mintz, P.J.; Hajitou, A.; Sarkis, A.S.; Arap, W.; Pasqualini, R. Cell surface expression of the stress response chaperone GRP78 enables tumor targeting by circulating ligands. Cancer Cell 2004, 6, 275–284. [Google Scholar] [CrossRef] [Green Version]
  116. Misra, U.K.; Mowery, Y.; Kaczowka, S.; Pizzo, S.V. Ligation of cancer cell surface GRP78 with antibodies directed against its COOH-terminal domain up-regulates p53 activity and promotes apoptosis. Mol. Cancer Ther. 2009, 8, 1350–1362. [Google Scholar] [CrossRef] [Green Version]
  117. Katanasaka, Y.; Ishii, T.; Asai, T.; Naitou, H.; Maeda, N.; Koizumi, F.; Miyagawa, S.; Ohashi, N.; Oku, N. Cancer antineovascular therapy with liposome drug delivery systems targeted to BiP/GRP78. Int. J. Cancer 2010, 127, 2685–2698. [Google Scholar] [CrossRef]
  118. Davidson, D.J.; Haskell, C.; Majest, S.; Kherzai, A.; Egan, D.A.; Walter, K.A.; Schneider, A.; Gubbins, E.F.; Solomon, L.; Chen, Z.; et al. Kringle 5 of human plasminogen induces apoptosis of endothelial and tumor cells through surface-expressed glucose-regulated protein 78. Cancer Res. 2005, 65, 4663–4672. [Google Scholar] [CrossRef] [Green Version]
  119. Bhattacharjee, G.; Ahamed, J.; Pedersen, B.; El-Sheikh, A.; Mackman, N.; Ruf, W.; Liu, C.; Edgington, T.S. Regulation of tissue factor—mediated initiation of the coagulation cascade by cell surface grp78. Arterioscler. Thromb. Vasc. Biol. 2005, 25, 1737–1743. [Google Scholar] [CrossRef]
  120. Pohle, T.; Brändlein, S.; Ruoff, N.; Müller-Hermelink, H.K.; Vollmers, H.P. Lipoptosis: Tumor-specific cell death by antibody-induced intracellular lipid accumulation. Cancer Res. 2004, 64, 3900–3906. [Google Scholar] [CrossRef] [Green Version]
  121. Brändlein, S.; Rauschert, N.; Rasche, L.; Dreykluft, A.; Hensel, F.; Conzelmann, E.; Müller-Hermelink, H.K.; Vollmers, H.P. The human IgM antibody SAM-6 induces tumor-specific apoptosis with oxidized low-density lipoprotein. Mol. Cancer Ther. 2007, 6, 326–333. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  122. Shevtsov, M.A.; Yakovleva, L.Y.; Nikolaev, B.P.; Marchenko, Y.Y.; Dobrodumov, A.V.; Onokhin, K.V.; Onokhina, Y.S.; Selkov, S.A.; Mikhrina, A.L.; Guzhova, I.V.; et al. Tumor targeting using magnetic nanoparticle Hsp70 conjugate in a model of C6 glioma. Neuro Oncol. 2014, 16, 38–49. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  123. Ito, A.; Matsuoka, F.; Honda, H.; Kobayashi, T. Antitumor effects of combined therapy of recombinant heat shock protein 70 and hyperthermia using magnetic nanoparticles in an experimental subcutaneous murine melanoma. Cancer Immunol. Immunother. 2004, 53, 26–32. [Google Scholar] [CrossRef] [PubMed]
  124. Di Cesare, S.; Poccia, F.; Mastino, A.; Colizzi, V. Surface expressed heat-shock proteins by stressed or human immunodeficiency virus (HIV)-infected lymphoid cells represent the target for antibody-dependent cellular cytotoxicity. Immunology 1992, 76, 341–343. [Google Scholar] [PubMed]
  125. Gaca, S.; Reichert, S.; Multhoff, G.; Wacker, M.; Hehlgans, S.; Botzler, C.; Gehrmann, M.; Rödel, C.; Kreuter, J.; Rödel, F. Targeting by cmHsp70.1-antibody coated and survivin miRNA plasmid loaded nanoparticles to radiosensitize glioblastoma cells. J. Control. Release 2013, 172, 201–206. [Google Scholar] [CrossRef] [PubMed]
  126. Stangl, S.; Gehrmann, M.; Dressel, R.; Alves, F.; Dullin, C.; Themelis, G.; Ntziachristos, V.; Staeblein, E.; Walch, A.; Winkelmann, I.; et al. In vivo imaging of CT26 mouse tumours by using cmHsp70.1 monoclonal antibody. J. Cell Mol. Med. 2011, 15, 874–887. [Google Scholar] [CrossRef] [Green Version]
  127. Gehrmann, M.K.; Kimm, M.A.; Stangl, S.; Schmid, T.E.; Noël, P.B.; Rummeny, E.J.; Multhoff, G. Imaging of Hsp70-positive tumors with cmHsp70.1 antibody-conjugated gold nanoparticles. Int. J. Nanomed. 2015, 10, 5687–5700. [Google Scholar] [CrossRef] [Green Version]
  128. Stangl, S.; Themelis, G.; Friedrich, L.; Ntziachristos, V.; Sarantopoulos, A.; Molls, M.; Skerra, A.; Multhoff, G. Detection of irradiation-induced, membrane heat shock protein 70 (Hsp70) in mouse tumors using Hsp70 Fab fragment. Radiother. Oncol. 2011, 99, 313–316. [Google Scholar] [CrossRef]
  129. Meng, Y.; Wang, S.; Li, C.; Qian, M.; Zheng, Y.; Yan, X.; Huang, R. TKD peptide as a ligand targeting drug delivery systems to memHsp70-positive breast cancer. Int. J. Pharm. 2016, 498, 40–48. [Google Scholar] [CrossRef]
  130. Gehrmann, M.; Stangl, S.; Foulds, G.A.; Oellinger, R.; Breuninger, S.; Rad, R.; Pockley, A.G.; Multhoff, G. Tumor imaging and targeting potential of an Hsp70-derived 14-mer peptide. PLoS ONE 2014, 9, e105344. [Google Scholar] [CrossRef] [Green Version]
  131. Friedrich, L.; Kornberger, P.; Mendler, C.T.; Multhoff, G.; Schwaiger, M.; Skerra, A. Selection of an Anticalin® against the membrane form of Hsp70 via bacterial surface display and its theranostic application in tumour models. Biol. Chem. 2018, 399, 235–252. [Google Scholar] [CrossRef] [PubMed]
  132. Zhang, M.; Wang, D.; Li, P.; Sun, C.; Xu, R.; Geng, Z.; Xu, W.; Dai, Z. Interaction of Hsp90 with phospholipid model membranes. Biochim. Biophys. Acta Biomembr. 2018, 1860, 611–616. [Google Scholar] [CrossRef] [PubMed]
  133. Csoboz, B.; Balogh, G.E.; Kusz, E.; Gombos, I.; Peter, M.; Crul, T.; Gungor, B.; Haracska, L.; Bogdanovics, G.; Torok, Z.; et al. Membrane fluidity matters: Hyperthermia from the aspects of lipids and membranes. Int. J. Hyperth. 2013, 29, 491–499. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  134. Török, Z.; Goloubinoff, P.; Horváth, I.; Tsvetkova, N.M.; Glatz, A.; Balogh, G.; Varvasovszki, V.; Los, D.A.; Vierling, E.; Crowe, J.H.; et al. Synechocystis HSP17 is an amphitropic protein that stabilizes heat-stressed membranes and binds denatured proteins for subsequent chaperone-mediated refolding. Proc. Natl. Acad. Sci. USA 2001, 98, 3098–3103. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  135. Balogi, Z.; Cheregi, O.; Giese, K.C.; Juhász, K.; Vierling, E.; Vass, I.; Vígh, L.; Horváth, I. A mutant small heat shock protein with increased thylakoid association provides an elevated resistance against UV-B damage in synechocystis 6803. J. Biol. Chem. 2008, 283, 22983–22991. [Google Scholar] [CrossRef] [Green Version]
  136. Balogi, Z.; Török, Z.; Balogh, G.; Jósvay, K.; Shigapova, N.; Vierling, E.; Vígh, L.; Horváth, I. “Heat shock lipid” in cyanobacteria during heat/light-acclimation. Arch. Biochem. Biophys. 2005, 436, 346–354. [Google Scholar] [CrossRef]
  137. Li, P.; Wang, J.; Zou, Y.; Sun, Z.; Zhang, M.; Geng, Z.; Xu, W.; Wang, D. Interaction of Hsp90AA1 with phospholipids stabilizes membranes under stress conditions. Biochim. Biophys. Acta Biomembr. 2019, 1861, 457–465. [Google Scholar] [CrossRef]
  138. Li, P.; Zhang, M.; Zou, Y.; Sun, Z.; Sun, C.; Geng, Z.; Xu, W.; Wang, D. Interaction of heat shock protein 90 B1 (Hsp90B1) with liposome reveals its potential role in protection the integrity of lipid membranes. Int. J. Biol. Macromol. 2018, 106, 1250–1257. [Google Scholar] [CrossRef]
  139. Lauwers, E.; Wang, Y.C.; Gallardo, R.; Van der Kant, R.; Michiels, E.; Swerts, J.; Baatsen, P.; Zaiter, S.S.; McAlpine, S.R.; Gounko, N.V.; et al. Hsp90 Mediates Membrane Deformation and Exosome Release. Mol. Cell 2018, 71, 689–702. [Google Scholar] [CrossRef] [Green Version]
  140. Chen, S.; Bawa, D.; Besshoh, S.; Gurd, J.W.; Brown, I.R. Association of heat shock proteins and neuronal membrane components with lipid rafts from the rat brain. J. Neurosci. Res. 2005, 81, 522–529. [Google Scholar] [CrossRef]
  141. Becker, B.; Multhoff, G.; Farkas, B.; Wild, P.J.; Landthaler, M.; Stolz, W.; Vogt, T. Induction of Hsp90 protein expression in malignant melanomas and melanoma metastases. Exp. Dermatol. 2004, 13, 27–32. [Google Scholar] [CrossRef] [PubMed]
  142. Snigireva, A.V.; Vrublevskaya, V.V.; Skarga, Y.Y.; Morenkov, O.S. The Role of Membrane-Bound Heat Shock Proteins Hsp90 in Migration of Tumor Cells in vitro and Involvement of Cell Surface Heparan Sulfate Proteoglycans in Protein Binding to Plasma Membrane. Biofizika 2016, 61, 328–336. [Google Scholar] [CrossRef] [PubMed]
  143. Tsutsumi, S.; Scroggins, B.; Koga, F.; Lee, M.J.; Trepel, J.; Felts, S.; Carreras, C.; Neckers, L. A small molecule cell-impermeant Hsp90 antagonist inhibits tumor cell motility and invasion. Oncogene 2008, 27, 2478–2487. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  144. Stellas, D.; Karameris, A.; Patsavoudi, E. Monoclonal antibody 4C5 immunostains human melanomas and inhibits melanoma cell invasion and metastasis. Clin. Cancer Res. 2007, 13, 1831–1838. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  145. Cid, C.; Regidor, I.; Poveda, P.D.; Alcazar, A. Expression of heat shock protein 90 at the cell surface in human neuroblastoma cells. Cell Stress Chaperones 2009, 14, 321–327. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  146. Sidera, K.; Samiotaki, M.; Yfanti, E.; Panayotou, G.; Patsavoudi, E. Involvement of cell surface HSP90 in cell migration reveals a novel role in the developing nervous system. J. Biol. Chem. 2004, 279, 379–388. [Google Scholar] [CrossRef] [Green Version]
  147. Erkeller-Yuksel, F.M.; Isenberg, D.A.; Dhillon, V.B.; Latchman, D.S.; Lydyard, P.M. Surface expression of heat shock protein 90 by blood mononuclear cells from patients with systemic lupus erythematosus. J. Autoimmun. 1992, 5, 803–814. [Google Scholar] [CrossRef]
  148. Li, W.; Li, Y.; Guan, S.; Fan, J.; Cheng, C.F.; Bright, A.M.; Chinn, C.; Chen, M.; Woodley, D.T. Extracellular heat shock protein-90alpha: Linking hypoxia to skin cell motility and wound healing. EMBO J. 2007, 26, 1221–1233. [Google Scholar] [CrossRef]
  149. Robert, J.; Ménoret, A.; Cohen, N. Cell surface expression of the endoplasmic reticular heat shock protein gp96 is phylogenetically conserved. J. Immunol. 1999, 163, 4133–4139. [Google Scholar]
  150. Melendez, K.; Wallen, E.S.; Edwards, B.S.; Mobarak, C.D.; Bear, D.G.; Moseley, P.L. Heat shock protein 70 and glycoprotein 96 are differentially expressed on the surface of malignant and nonmalignant breast cells. Cell Stress Chaperones 2006, 11, 334–342. [Google Scholar] [CrossRef] [Green Version]
  151. Chavany, C.; Mimnaugh, E.; Miller, P.; Bitton, R.; Nguyen, P.; Trepel, J.; Whitesell, L.; Schnur, R.; Moyer, J.; Neckers, L. p185erbB2 binds to GRP94 in vivo. Dissociation of the p185erbB2/GRP94 heterocomplex by benzoquinone ansamycins precedes depletion of p185erbB2. J. Biol. Chem. 1996, 271, 4974–4977. [Google Scholar] [PubMed] [Green Version]
  152. Patel, P.D.; Yan, P.; Seidler, P.M.; Patel, H.J.; Sun, W.; Yang, C.; Que, N.S.; Taldone, T.; Finotti, P.; Stephani, R.A.; et al. Paralog-selective Hsp90 inhibitors define tumor-specific regulation of HER2. Nat. Chem. Biol. 2013, 9, 677–684. [Google Scholar] [CrossRef] [PubMed]
  153. Koo, B.H.; Apte, S.S. Cell-surface processing of the metalloprotease pro-ADAMTS9 is influenced by the chaperone GRP94/gp96. J. Biol. Chem. 2010, 285, 197–205. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  154. Martins, M.; Custódio, R.; Camejo, A.; Almeida, M.T.; Cabanes, D.; Sousa, S. Listeria monocytogenes triggers the cell surface expression of Gp96 protein and interacts with its N terminus to support cellular infection. J. Biol. Chem. 2012, 287, 43083–43093. [Google Scholar] [CrossRef] [Green Version]
  155. Mittal, R.; Prasadarao, N.V. gp96 expression in neutrophils is critical for the onset of Escherichia coli K1 (RS218) meningitis. Nat. Commun. 2011, 2, 552. [Google Scholar] [CrossRef] [Green Version]
  156. Cabanes, D.; Sousa, S.; Cebriá, A.; Lecuit, M.; García-del Portillo, F.; Cossart, P. Gp96 is a receptor for a novel Listeria monocytogenes virulence factor, Vip, a surface protein. EMBO J. 2005, 24, 2827–2838. [Google Scholar] [CrossRef]
  157. Wiest, D.; Bhandoola, A.; Punt, J.; Kreibich, G.; McKean, D.; Singer, A. Incomplete endoplasmic reticulum (ER) retention in immature thymocytes as revealed by surface expression of “ER-resident” molecular chaperones. Proc. Natl. Acad. Sci. USA 1997, 94, 1884–1889. [Google Scholar] [CrossRef] [Green Version]
  158. Hou, J.; Li, X.; Li, C.; Sun, L.; Zhao, Y.; Zhao, J.; Meng, S. Plasma membrane gp96 enhances invasion and metastatic potential of liver cancer via regulation of uPAR. Mol. Oncol. 2015, 9, 1312–1323. [Google Scholar] [CrossRef] [Green Version]
  159. Li, X.; Wang, B.; Liu, W.; Gui, M.; Peng, Z.; Meng, S. Blockage of conformational changes of heat shock protein gp96 on cell membrane by a α-helix peptide inhibits HER2 dimerization and signaling in breast cancer. PLoS ONE 2015, 10, e0124647. [Google Scholar] [CrossRef]
  160. Li, X.; Sun, L.; Hou, J.; Gui, M.; Ying, J.; Zhao, H.; Lv, N.; Meng, S. Cell membrane gp96 facilitates HER2 dimerization and serves as a novel target in breast cancer. Int. J. Cancer 2015, 137, 512–524. [Google Scholar] [CrossRef]
  161. Nakamoto, H.; Vígh, L. The small heat shock proteins and their clients. Cell Mol. Life Sci. 2007, 64, 294–306. [Google Scholar] [CrossRef] [PubMed]
  162. De Maio, A.; Cauvi, D.M.; Capone, R.; Bello, I.; Egberts, W.V.; Arispe, N.; Boelens, W. The small heat shock proteins, HSPB1 and HSPB5, interact differently with lipid membranes. Cell Stress Chaperones 2019, 24, 947–956. [Google Scholar] [CrossRef] [PubMed]
  163. Tjondro, H.C.; Xi, Y.B.; Chen, X.J.; Su, J.T.; Yan, Y.B. Membrane insertion of αA-crystallin is oligomer-size dependent. Biochem. Biophys. Res. Commun. 2016, 473, 1–7. [Google Scholar] [CrossRef] [PubMed]
  164. Ifeanyi, F.; Takemoto, L. Interaction of lens crystallins with lipid vesicles. Exp. Eye Res. 1991, 52, 535–538. [Google Scholar] [CrossRef]
  165. Borchman, D.; Tang, D. Binding capacity of alpha-crystallin to bovine lens lipids. Exp. Eye Res. 1996, 63, 407–410. [Google Scholar] [CrossRef]
  166. Grami, V.; Marrero, Y.; Huang, L.; Tang, D.; Yappert, M.C.; Borchman, D. alpha-Crystallin binding in vitro to lipids from clear human lenses. Exp. Eye Res. 2005, 81, 138–146. [Google Scholar] [CrossRef]
  167. Bausero, M.A.; Page, D.T.; Osinaga, E.; Asea, A. Surface expression of Hsp25 and Hsp72 differentially regulates tumor growth and metastasis. Tumour. Biol. 2004, 25, 243–251. [Google Scholar] [CrossRef] [Green Version]
  168. Chowdary, T.K.; Raman, B.; Ramakrishna, T.; Rao, C.M. Interaction of mammalian Hsp22 with lipid membranes. Biochem. J. 2007, 401, 437–445. [Google Scholar] [CrossRef]
  169. Cicconi, R.; Delpino, A.; Piselli, P.; Castelli, M.; Vismara, D. Expression of 60 kDa heat shock protein (Hsp60) on plasma membrane of Daudi cells. Mol. Cell. Biochem. 2004, 259, 1–7. [Google Scholar] [CrossRef]
  170. Campanella, C.; Bucchieri, F.; Merendino, A.M.; Fucarino, A.; Burgio, G.; Corona, D.F.; Barbieri, G.; David, S.; Farina, F.; Zummo, G.; et al. The odyssey of Hsp60 from tumor cells to other destinations includes plasma membrane-associated stages and Golgi and exosomal protein-trafficking modalities. PLoS ONE 2012, 7, e42008. [Google Scholar] [CrossRef] [Green Version]
  171. Pfister, G.; Stroh, C.M.; Perschinka, H.; Kind, M.; Knoflach, M.; Hinterdorfer, P.; Wick, G. Detection of HSP60 on the membrane surface of stressed human endothelial cells by atomic force and confocal microscopy. J. Cell Sci. 2005, 118, 1587–1594. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  172. Gupta, S.; Knowlton, A.A. Cytosolic heat shock protein 60, hypoxia, and apoptosis. Circulation 2002, 106, 2727–2733. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  173. Lin, L.; Kim, S.C.; Wang, Y.; Gupta, S.; Davis, B.; Simon, S.I.; Torre-Amione, G.; Knowlton, A.A. HSP60 in heart failure: Abnormal distribution and role in cardiac myocyte apoptosis. Am. J. Physiol. Heart Circ. Physiol. 2007, 293, 2238–2247. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  174. Belles, C.; Kuhl, A.; Nosheny, R.; Carding, S.R. Plasma membrane expression of heat shock protein 60 in vivo in response to infection. Infect. Immun. 1999, 67, 4191–4200. [Google Scholar] [CrossRef] [Green Version]
  175. Burkholder, K.M.; Bhunia, A.K. Listeria monocytogenes uses Listeria adhesion protein (LAP) to promote bacterial transepithelial translocation and induces expression of LAP receptor Hsp60. Infect. Immun. 2010, 78, 5062–5073. [Google Scholar] [CrossRef] [Green Version]
  176. Elton, C.M.; Smethurst, P.A.; Eggleton, P.; Farndale, R.W. Physical and functional interaction between cell-surface calreticulin and the collagen receptors integrin alpha2beta1 and glycoprotein VI in human platelets. Thromb. Haemost. 2002, 88, 648–654. [Google Scholar] [CrossRef]
  177. Tarr, J.M.; Young, P.J.; Morse, R.; Shaw, D.J.; Haigh, R.; Petrov, P.G.; Johnson, S.J.; Winyard, P.G.; Eggleton, P. A mechanism of release of calreticulin from cells during apoptosis. J. Mol. Biol. 2010, 401, 799–812. [Google Scholar] [CrossRef]
  178. Paidassi, H.; Tacnet-Delorme, P.; Verneret, M.; Gaboriaud, C.; Houen, G.; Duus, K.; Ling, W.L.; Arlaud, G.J.; Frachet, P. Investigations on the C1q-calreticulin-phosphatidylserine interactions yield new insights into apoptotic cell recognition. J. Mol. Biol. 2011, 408, 277–290. [Google Scholar] [CrossRef]
  179. Kepp, O.; Gdoura, A.; Martins, I.; Panaretakis, T.; Schlemmer, F.; Tesniere, A.; Fimia, G.M.; Ciccosanti, F.; Burgevin, A.; Piacentini, M.; et al. Lysyl tRNA synthetase is required for the translocation of calreticulin to the cell surface in immunogenic death. Cell Cycle 2010, 9, 3072–3077. [Google Scholar] [CrossRef]
  180. Obeid, M. ERP57 membrane translocation dictates the immunogenicity of tumor cell death by controlling the membrane translocation of calreticulin. J. Immunol. 2008, 181, 2533–2543. [Google Scholar] [CrossRef] [Green Version]
  181. Takeuchi, T.; Suzuki, M.; Fujikake, N.; Popiel, H.A.; Kikuchi, H.; Futaki, S.; Wada, K.; Nagai, Y. Intercellular chaperone transmission via exosomes contributes to maintenance of protein homeostasis at the organismal level. Proc. Natl. Acad. Sci. USA 2015, 112, 2497–2506. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  182. Hirai, K.; Kikuchi, S.; Kurita, A.; Ohashi, S.; Adachi, E.; Matsuoka, Y.; Nagata, K.; Watanabe, M. Immunohistochemical distribution of heat shock protein 47 (HSP47) in scirrhous carcinoma of the stomach. AntiCancer Res. 2006, 26, 71–78. [Google Scholar] [PubMed]
  183. Yamamoto, N.; Kinoshita, T.; Nohata, N.; Yoshino, H.; Itesako, T.; Fujimura, L.; Mitsuhashi, A.; Usui, H.; Enokida, H.; Nakagawa, M.; et al. Tumor-suppressive microRNA-29a inhibits cancer cell migration and invasion via targeting HSP47 in cervical squamous cell carcinoma. Int. J. Oncol. 2013, 43, 1855–1863. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  184. Hebert, C.; Norris, K.; Della Coletta, R.; Reynolds, M.; Ordóñez, J.; Sauk, J.J. Cell surface colligin/Hsp47 associates with tetraspanin protein CD9 in epidermoid carcinoma cell lines. J. Cell Biochem. 1999, 73, 248–258. [Google Scholar] [CrossRef]
  185. Escribá, P.V.; Busquets, X.; Inokuchi, J.; Balogh, G.; Török, Z.; Horváth, I.; Harwood, J.L.; Vígh, L. Membrane lipid therapy: Modulation of the cell membrane composition and structure as a molecular base for drug discovery and new disease treatment. Prog. Lipid Res. 2015, 59, 38–53. [Google Scholar] [CrossRef] [Green Version]
  186. Nicolson, G.L.; Ash, M.E. Membrane Lipid Replacement for chronic illnesses, aging and cancer using oral glycerolphospholipid formulations with fructooligosaccharides to restore phospholipid function in cellular membranes, organelles, cells and tissues. Biochim. Biophys. Acta Biomembr. 2017, 1859, 1704–1724. [Google Scholar] [CrossRef]
  187. Balogh, G.; Maulucci, G.; Gombos, I.; Horváth, I.; Török, Z.; Péter, M.; Fodor, E.; Páli, T.; Benko, S.; Parasassi, T.; et al. Heat stress causes spatially-distinct membrane re-modelling in K562 leukemia cells. PLoS ONE 2011, 6, e21182. [Google Scholar] [CrossRef] [Green Version]
  188. Crul, T.; Csoboz, B.; Gombos, I.; Marton, A.; Peter, M.; Balogh, G.; Vizler, C.; Szente, L.; Vigh, L. Modulation of Plasma Membrane Composition and Microdomain Organization Impairs Heat Shock Protein Expression in B16-F10 Mouse Melanoma Cells. Cells 2020, 9, 951. [Google Scholar] [CrossRef]
Cells 09 01263 g001 550
Figure 1. Membrane-associated heat shock proteins and their role in tumor pathogenesis.
Figure 1. Membrane-associated heat shock proteins and their role in tumor pathogenesis.
Cells 09 01263 g001
Table
Table 1. Application of the membrane-associated Hsp70 and GRP78 for tumor theranostics.
Table 1. Application of the membrane-associated Hsp70 and GRP78 for tumor theranostics.
mHsp70-Targeted Strategies
mHsp70-Targeting ToolDrug and Adjuvant TherapyApplicationModelInjection RouteResultsRef.
DiagnosticsTherapy
rhHsp70rhHsp70-I123
rhHsp70-Alexa Fluor555
(1)
Single-photon emission computer tomography (SPECT);
(2)
Confocal microscopy
N/A
(1)
s.c. B16/F10 melanoma in C57Bl/6 mice,
(2)
o.t. C6 glioma in Wistar rats
i.v.Accumulation of the rhHsp70-I123 in B16/F10 melanoma (24 h, KDN tumor/background = 3.43).
Accumulation of rhHsp70-Alexa Fluor555 in C6 glioma after 24 h		[44]
rhHsp70rhHsp70N/A+o.t. C6 glioma in Wistar ratsi.t.Increased OS.
Enhanced infiltration of glioma with NK cells (Ly-6c+), T cells (CD3+, CD4+, CD8+).
Elevated production of IFNγ and granzyme B		[45,47]
Hsp70Hsp70-SPIONsMRIN/Ao.t. C6 glioma in Wistar ratsi.v.Contrast MR enhancement[122]
Hsp70Hsp70-hydrogel + phloretinN/A+s.c. B16 melanoma in C57Bl/6 micehydrogel + phloretinIncreased OS.
Activation of innate and adaptive immune responses		[49]
Hsp70Hsp70-hydrogelN/A+s.c. B16F10 melanoma in C57Bl/6 micehydrogelReduced rate of tumor growth by 64%.
Prolonged OS by 46%		[46]
rmHsp70rmHsp70 + hyperthermiaN/A+s.c. B16 melanoma in C57Bl/6 micei.t.Reduced tumor growth.
Complete regression in 20% (2/10) of the mice.
Induction of systemic anti-tumor immunity		[123]
Anti-Hsp72.000 MW antibodyAnti-Hsp70 antibodyN/A+in vitro Daudi cells (Burkitt B lymphoma), HIV+ H9 cells (CD4+ T cell lymphoma)N/AEnhanced ADCC against tumor cells[124]
cmHsp70.1 antibodiescmHsp70.1-miRNA (survivin)-NPN/A+in vitro human U87 and LN229 glioblastoma cellsN/AEnhanced radiation-induced increase in caspase 3/7 activity.
Decrease in clonogenic cell survival		[125]
cmHsp70.1 antibodiesCy5.5-cmHsp70.1Intra-operative and near-infrared fluorescence imagingN/Ai.p. and s.c. CT26 colon tumors in Balb/c micei.v.Epifluorescence imaging of mHsp70+ CT26 tumors[126]
cmHsp70.1 antibodiescmHsp70.1 antibodiesN/A+s.c. CT26 tumors in Balb/c micei.v.Induction of ADCC of mHsp70+ tumors.
Inhibition of tumor growth.
Increased OS		[50]
cmHsp70.1 antibodiesSPION-cmHsp70.1MRIN/Ao.t. C6 glioma in Wistar ratsi.v.Contrast MR enhancement[67]
cmHsp70.1 antibodiescmHsp70.1-conjugated gold nanoparticlesLight microscopyN/Ain vitro
CT26, 4T1+, 4T1 cells		N/ASpecific accumulation of functionalized gold nanoparticles in mHsp70+ tumor cells[127]
Hsp70-specific recombinant Fab fragment (Hsp70 Fab)Cy5.5-Hsp70 FabFluorescence microscopyN/As.c. CT26 colon tumors in Balb/c micei.v.Fluorescence imaging of mHsp70+ CT26 tumors[128]
TPP peptideTPP-PEG24-DFO [89Zr]PETN/A
(1)
s.c. 4T1+ (mHsp70+) and 4T1wt breast carcinoma in Balb/c mice;
(2)
s.c. CT26 colon tumors in Balb/c mice
i.v.Tumor-specific accumulation of the tracer in 4T1+ (6.2±1.1%ID/g), 4T1 (4.3±0.7%ID/g), and CT26 (2.6±0.6%ID/g) tumors[52]
TKD peptideTKD-modified doxorubicin (DOX)-loaded micelles (TKD-D-M)N/A+s.c. MCF-7 breast tumors in Balb/c micei.v.Accumulation of TKD-micelles in tumors.
Inhibition of tumor cell proliferation		[129]
TPP peptideCarboxy-fluorescein (CF)-labeled TPPConfocal microscopyN/Ain vitro
MCF7 (82% mHsp70+), MDA-MB-231 (75% mHsp70+), T47D (29% mHsp70+), 4T1 and 4T1+ (>90% mHsp70+) cells		N/ASpecific binding and internalization by mHsp70+ tumor cells[130]
TPP peptideTPP [Cy5.5]Epifluorescence microscopyN/Aspontaneous pancreatic ductal adenocarcinoma (PDAC) mouse model,
colitis-associated spontaneous tumor model in FvB mice,
xenograft mouse model in SHO mice (HCT-116, CX-2, colon ca), (MCF-7, MDA-MB231, T-47D mammary ca), (Panc-1, MIA PaCa-2, COLO357, pancreatic CA), (H1339, A549; lung), (FaDu, Cal-33 head and neck ca), (HeLa, cervix ca)		i.v.Epifluorescence imaging of mHsp70+ tumors[51]
Granzyme BGranzyme BN/A+s.c. CT26 colon tumors in Balb/c micei.v.Suppression of tumor growth[81]
Granzyme B
(1)
GrB-SPIONs;
(2)
GrB-Alexa688
(1)
MRI;
(2)
Epifluorescence microscopy
+o.t. C6 glioma in Wistar rats,
o.t. human U87 glioma in NMRI nu/nu mice,
o.t. mouse GL261 glioma in C57Bl/6 mice,
o.t. human H1339 SCLC in NMRI nu/nu mice		i.v.Contrast MR (GrB-SPIONs);
Increased OS;
Intraoperative tumor imaging (24 h, GrB-Alexa688)		[91]
Anticalin89Zr-AnticalinPETN/As.c. FaDu tumors in immunodeficient CD1-Foxn1nu micei.v.PET contrast enhancement in tumors[131]
mGRP78-Targeted Strategies
mHsp70-Targeting ToolDrug and Adjuvant TherapyApplicationModelAdministrationResultsRef.
DiagnosticsTherapy
Anti-GRP78 synthetic chimeric peptides (i.e., WIFPWIQL, WDLAWMFRLPVG)Chimeric peptides fused with programmed cell death-inducing sequence (pro-apoptotic motif D(KLAKLAK)2)N/A+DU145-derived human prostate cancer in nude mice,
EF43-fgf4-derived isogenic tumors in Balb/c mice		i.v.Suppression of tumor growth[115]
Antibodies towards the COOH-terminal domain of GRP78Antibodies towards the COOH-terminal domain of GRP78N/A+in vitro
1-LN and DU145 prostate cancer cells, A375 melanoma cells		N/AAnti-tumor pro-apoptotic activity due to an upregulation of p53[116]
Anti-GRP78 targeting peptide WIFPWIQLWIFPWIQL-modified liposomes containing doxorubicinN/A+s.c. colon CT26 NL-17 carcinoma in Balb/c micei.v.Suppression of tumor growth and increase in OS.
Inhibition of tumor-induced angiogenesis		[117]
Human IgM antibody (SAM-6)Human monoclonal IgM antibody (SAM-6)N/A+s.c. mouse/human stomach carcinomas in NMRI nu/nu micei.p.Tumor suppression[121]
Human IgM antibody (SAM-6)Human IgM antibody (SAM-6)N/A+in vitro 23132/87 and BXPC-3, nasal septum squamous cell carcinoma RPMI-2650N/ATumor cell death via lipoptosis[120]
Table
Table 2. Application of the membrane-associated Hsp90 and GRP96 for tumor theranostics.
Table 2. Application of the membrane-associated Hsp90 and GRP96 for tumor theranostics.
mHsp90-Targeted Strategies
mHsp90-Targeting ToolDrug and Adjuvant TherapyApplicationModelAdministrationResultsRef.
DiagnosticsTherapy
Anti-Hsp90 monoclonal antibody 1.5.1 and scFvs (IIIF1, IH5, IID3, IIC1, IIIG7, IIIC6)Anti-Hsp90 antibody or scFvsN/A+in vitro HT-1080 fibrosarcoma cellsN/ASignificant inhibition of tumor cell invasion[16]
Anti-Hsp90 monoclonal antibody 4C5Anti-Hsp90 monoclonal antibody 4C5N/A+in vitro MDA-MB453
human breast carcinoma cells		N/AInhibition of cell invasion accompanied by altered actin dynamics.
Disruption of surface HSP90/HER-2 inter-action that resulted in reduced HER-2 phosphorylation and impaired downstream kinase signaling		[146]
Anti-Hsp90 monoclonal antibody 4C5Anti-Hsp90 monoclonal antibody 4C5N/A+i.v. injection B16F10 melanoma in C57Bl/6 micei.p.Significant inhibition of melanoma metastasis[144]
(1)
DMAG-N-oxide, cell-impermeable Hsp90 inhibitor;
(2)
Anti-Hsp90 antibody (SPA-830) targeting C-terminus
(1)
DMAG-N-oxide, cell-impermeable Hsp90 inhibitor;
(2)
Anti-Hsp90 monoclonal antibody
N/A+in vitro T24, B16-luc, PC3M cells
i.v. injection B16 melanoma cells in Nu/Nu mice
s.c. B16 melanoma in Nu/Nu mice		i.v.Significant in vitro inhibition of cell motility and invasion.
Decrease in tumor cell colonization		[143]
mGrp96-Targeted Strategies
mHsp90-Targeting ToolDrug and Adjuvant TherapyApplicationModelAdministrationResultsRef.
DiagnosticsTherapy
(1)
Anti-mGrp96 siRNA;
(2)
Anti-mGrp96 antibody
(1)
Anti-mGrp96 siRNA;
(2)
Anti-mGrp96 antibody
N/A+s.c.
SK-Hep1 cells in nude mice,
s.c. Huh7 cells in nude mice		i.p.Inhibition of tumor growth and lung metastasis[158]
Anti-mGrp96 antibodyAnti-mGrp96 antibodyN/A+s.c.
SK-BR-3, T47D cells in Balb/c mice		i.v.Induction of apoptosis and decrease in tumor growth[160]
Anti-mGrp96 single α-helix peptide p37Anti-mGrp96 single α-helix peptide p37N/A+o.t. T47D, Bcap37 cells in nude micei.v.Inhibition of tumor growth[159]

Share and Cite

MDPI and ACS Style

Shevtsov, M.; Balogi, Z.; Khachatryan, W.; Gao, H.; Vígh, L.; Multhoff, G. Membrane-Associated Heat Shock Proteins in Oncology: From Basic Research to New Theranostic Targets. Cells 2020, 9, 1263. https://doi.org/10.3390/cells9051263

AMA Style

Shevtsov M, Balogi Z, Khachatryan W, Gao H, Vígh L, Multhoff G. Membrane-Associated Heat Shock Proteins in Oncology: From Basic Research to New Theranostic Targets. Cells. 2020; 9(5):1263. https://doi.org/10.3390/cells9051263

Chicago/Turabian Style

Shevtsov, Maxim, Zsolt Balogi, William Khachatryan, Huile Gao, László Vígh, and Gabriele Multhoff. 2020. "Membrane-Associated Heat Shock Proteins in Oncology: From Basic Research to New Theranostic Targets" Cells 9, no. 5: 1263. https://doi.org/10.3390/cells9051263

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop