Heat shock proteins as cellular lifeguards

Variations in HSPA1B at 6p21.3 are associated with lung cancer risk and prognosis in Chinese populations

The heat shock protein Hsp70 is crucial for regulating cellular homeostasis in stressed cells. Although the tumorigenic potential and prognostic applications of Hsp70 have been widely investigated, it remains unclear whether genetic variations of the human isoforms HSPA1L, HSPA1A, and HSPA1B are associated with cancer risk and prognosis. In this study, we genotyped six tagSNPs in these genes in 1,152 paired patients with lung cancer and controls, and then validated the results in additional cohorts of 1,781 patients with lung cancer and 1,038 controls. In addition, we evaluated the associations of these tagSNPs with survival in 330 patients with advanced non-small cell lung cancer (NSCLC) with additional validation in another 331 patients with advanced NSCLC. Functions of the risk variants identified were investigated using cell-based reporter assays. We found that the HSPA1B rs6457452T allele was associated with increased lung cancer risk compared with the rs6457452C allele in both data sets and also pooled analysis (adjusted OR = 1.41; P = 2.8 × 10(-5)). The HSPA1B rs2763979TT genotype conferred poor survival outcomes for patients with advanced NSCLC in two independent cohorts and pooled analysis [adjusted hazard ratio (HR) = 1.80, 1.61, and 1.66; P = 0.013, 0.036, and 0.002, respectively]. Lastly, we also found that the rs2763979T and rs6457452T alleles were each sufficient to reduce expression of transcriptional reporter constructs, when compared with the rs2763979C and rs6457452C alleles, respectively. Taken together, our findings define that functional HSPA1B variants are associated with lung cancer risk and survival. These Hsp70 genetic variants may offer useful biomarkers to predict lung cancer risk and prognosis.

Inducible hsp70 in the regulation of cancer cell survival: analysis of chaperone induction, expression and activity

Understanding the mechanisms that control stress is central to realize how cells respond to environmental and physiological insults. All the more important is to reveal how tumour cells withstand their harsher growth conditions and cope with drug-induced apoptosis, since resistance to chemotherapy is the foremost complication when curing cancer. Intensive research on tumour biology over the past number of years has provided significant insights into the molecular events that occur during oncogenesis, and resistance to anti-cancer drugs has been shown to often rely on stress response and expression of inducible heat shock proteins (HSPs). However, with respect to the mechanisms guarding cancer cells against proteotoxic stresses and the modulatory effects that allow their survival, much remains to be defined. Heat shock proteins are molecules responsible for folding newly synthesized polypeptides under physiological conditions and misfolded proteins under stress, but their role in maintaining the transformed phenotype often goes beyond their conventional chaperone activity. Expression of inducible HSPs is known to correlate with limited sensitivity to apoptosis induced by diverse cytotoxic agents and dismal prognosis of several tumour types, however whether cancer cells survive because of the constitutive expression of heat shock proteins or the ability to induce them when adapting to the hostile microenvironment remains to be elucidated. Clear is that tumours appear nowadays more "addicted" to heat shock proteins than previously envisaged, and targeting HSPs represents a powerful approach and a future challenge for sensitizing tumours to therapy. This review will focus on the anti-apoptotic role of heat shock 70kDa protein (Hsp70), and how regulatory factors that control inducible Hsp70 synthesis, expression and activity may be relevant for response to stress and survival of cancer cells.

Heat shock protein as molecular targets for breast cancer therapeutics

Recent advances in the understanding of the molecular mechanisms involved in the breast cancer development and progression have led to the identification of numerous novel molecular targets. Among these, heat shock proteins (HSPs) are being emerging molecular target due to its diverse function in cancer cells. HSPs are highly conserved molecular chaperone that are synthesized by cell in response to various stress conditions. Mammalian HSPs have been classified into several families according to their molecular weight: HSP100, HSP90, HSP72, and small molecular HSPs (including HSP27). They are essential proteins that play a key role in cell survival through the cytoprotective mechanisms. In addition, HSPs are often overexpressed in a rage of cancers including breast cancer, and its overexpression seems to be associated with poor clinical outcomes. Also, HSP90 play a role in facilitating transformation by stabilizing the mutated and overexpressed oncoproteins found in breast cancer cell. Pharmacological targeting of HSP is therefore indicated and in the case of HSP90, numerous inhibitory drugs are undergoing clinical trial for treatment of breast cancer and other cancers. In this review, we describe the roles of HSPs in cancer cell and introduce the HSPs inhibitor as molecular target in cancer therapy and its recent clinical trials in breast cancer.

Optimization of Salmonella enteritidis recombinant heat shock protein 60 production

The aim of the study was to optimize conditions for producing Salmonella Enteritidis recombinant heat shock protein 60 (rHsp60). Seven Escherichia coli host strains (Rosetta, Turner, C41, C43, Origami, BL21pLys, Rosetta pLys) were transformed by a recombinant plasmid containing Hsp60 gene from Salmonella Enteritidis, and then cultured and induced by isopropyl-beta-D-thiogalactopyranoside (IPTG). The highest S. Enteritidis rHsp60 yield was obtained using E. coli strain C41. Induction of this strain using IPTG allowed the yield 400 microg of S. Enteritidis Hsp60 protein/2L of culture, but by autoinduction the yield exceeded 800 microg/2L.

Cellular stress response pathways and ageing: intricate molecular relationships

Ageing is driven by the inexorable and stochastic accumulation of damage in biomolecules vital for proper cellular function. Although this process is fundamentally haphazard and uncontrollable, senescent decline and ageing is broadly influenced by genetic and extrinsic factors. Numerous gene mutations and treatments have been shown to extend the lifespan of diverse organisms ranging from the unicellular Saccharomyces cerevisiae to primates. It is becoming increasingly apparent that most such interventions ultimately interface with cellular stress response mechanisms, suggesting that longevity is intimately related to the ability of the organism to effectively cope with both intrinsic and extrinsic stress. Here, we survey the molecular mechanisms that link ageing to main stress response pathways, and mediate age-related changes in the effectiveness of the response to stress. We also discuss how each pathway contributes to modulate the ageing process. A better understanding of the dynamics and reciprocal interplay between stress responses and ageing is critical for the development of novel therapeutic strategies that exploit endogenous stress combat pathways against age-associated pathologies.

Heat shock proteins in oncology: diagnostic biomarkers or therapeutic targets?

Heat shock proteins (HSP) are a family of proteins induced in cells exposed to different insults. This induction of HSPs allows cells to survive stress conditions. Mammalian HSPs have been classified into six families according to their molecular size: HSP100, HSP90, HSP70, HSP60, HSP40 and small HSPs (15 to 30kDa) including HSP27. These proteins act as molecular chaperones either helping in the refolding of misfolded proteins or assisting in their elimination if they become irreversibly damaged. In recent years, proteomic studies have characterized several different HSPs in various tumor types which may be putative clinical biomarkers or molecular targets for cancer therapy. This has led to the development of a series of molecules capable of inhibiting HSPs. Numerous studies speculated that over-expression of HSP is in part responsible for resistance to many anti-tumor agents and chemotherapeutics. Hence, from a pharmacological point of view, the co-administration of HSP inhibitors together with other anti-tumor agents is of major importance in overcoming therapeutic resistance. In this review, we provide an overview of the current status of HSPs in autoimmune, cardiovascular, and neurodegenerative diseases with special emphasis on cancer.

Inducers and co-inducers of molecular chaperones

Molecular chaperones, which are mostly heat- or stress-induced proteins (HSPs), not only regulate various cellular functions such as protein folding, refolding of partially denatured proteins, protein transport across membranes, cytoskeletal organization, degradation of disabled proteins, and apoptosis, but also act as cytoprotective factors against deleterious environmental stresses. Recent studies indicated that moderate overexpression of molecular chaperones could confer cells and tissues stress tolerance and provide beneficial effects on various pathological states associated with protein misfolding and protein aggregation. Mild heat shock, transfection of HSP genes, and some chemical compounds are the major means of overexpression of molecular chaperones. In this review, we summarize recent studies of chemical compounds that could induce or enhance the expression of molecular chaperones or HSPs.

HSP70 protein promotes survival of C6 and U87 glioma cells by inhibition of ATF5 degradation

Although both the heat shock protein 70 (HSP70) and the activating transcription factor 5 (ATF5) have been shown to promote cell survival of transformed cells but not survival of non-transformed cells, the relationship of the two molecules is unknown. Here we show that HSP70 and ATF5 are concomitantly up-regulated upon transient but down-regulated over prolonged cellular stress and apoptotic stimulation in the rat C6 glioma and human U87 glioma cells. HSP70 interacts strongly with the N-terminal activation domain of ATF5, which is expected to be rigid and uniquely structured under physiological conditions because of extraordinary high concentration (over 25%) of proline residues. Binding of HSP70 to ATF5 is an ATP-driven process and requires functional ATPase on the nucleotide binding domain of the HSP70 molecule. Overexpression of HSP70 dramatically stabilizes the ATF5 protein, which is otherwise subject to rapid degradation, facilitated by both proteasome-dependent and caspase-dependent processes, whereas HSP70 depletion leads to acceleration of ATF5 degradation and transcription repression of Bcl-2 and Egr-1, which are downstream targets of ATF5 in C6 and U87 glioma cells. Our data reveal an essential role for HSP70 in maintaining high levels of ATF5 expression in glioma cells and support the conclusion that ATF5 is an important substrate protein of HSP70 that mediates HSP70-promoted cell survival in glioma cells.

Heat shock proteins in the human eye

Heat shock proteins (Hsps) are believed to primarily protect and maintain cell viability under stressful conditions such as those occurring during thermal and oxidative challenges chiefly by refolding and stabilizing proteins. Hsps are found throughout the various tissues of the eye where they are thought to confer protection from disease states such as cataract, glaucoma, and cancer. This minireview summarizes the placement, properties, and roles of Hsps in the eye and aims to provide a better comprehension of their function and involvement in ocular disease pathogenesis.

Proteome analysis of proteins related to aggressive periodontitis combined with neutrophil chemotaxis dysfunction

AIM

Some patients suffering from aggressive periodontitis (Ag-P) also display neutrophil chemotaxis dysfunction. In this study, we attempted to identify the proteins involved in Ag-P associated with neutrophil chemotaxis dysfunction using proteome analysis.

MATERIAL AND METHODS

A two-dimensional fluorescence difference gel electrophoresis system was used to detect differences in protein expression between neutrophils from four patients suffering from Ag-P combined with neutrophil chemotaxis dysfunction and those from four controls. Moreover, the mRNA levels of the proteins identified by the above method were examined in neutrophils from four types of subjects using the real-time polymerase chain reaction: twenty patients suffering from Ag-P with or without the dysfunction, 15 patients with chronic periodontitis, and 15 controls.

RESULTS

Four proteins, lactoferrin, caldesmon, heat shock protein 70, and stac, displayed a higher protein expression level in the neutrophils from the patients suffering from Ag-P combined with the neutrophil dysfunction than in those from the control group. The caldesmon mRNA levels in the neutrophils from the patients suffering from Ag-P combined with the neutrophil dysfunction were high compared with those in the neutrophils from the patients suffering from the other two types of periodontitis and those from the control group.

CONCLUSION

Caldesmon may be a marker of Ag-P combined with neutrophil chemotaxis dysfunction.

Hsp70: anti-apoptotic and tumorigenic protein

Heat shock protein 70 (Hsp70) is a powerful chaperone whose expression is induced in response to a wide variety of physiological and environmental insults, including anticancer chemotherapy, thus allowing the cell to survive to lethal conditions. Hsp70 cytoprotective properties may be explained by its anti-apoptotic function. Indeed, this protein can inhibit key effectors of the apoptotic machinery at the pre- and postmitochondrial level. In cancer cells, the expression of Hsp70 is abnormally high, and Hsp70 may participate in oncogenesis and in resistance to chemotherapy. In rodent models, Hsp70 overexpression increases tumor growth and metastatic potential. Depletion or inhibition of Hsp70 frequently reduces the size of the tumors and even can cause their complete involution. But Hsp70 can also be found in the extracellular medium. Its role is then immunogenic and the term chaperokine to define the extracellular chaperones has been advanced. Hsp70 tumorigenic functions as well as the strategies that are being developed in cancer therapy in order to inhibit Hsp70 are commented in this chapter.

Targeting heat shock proteins in cancer

Heat shock proteins (HSPs) HSP27, HSP70 and HSP90 are powerful chaperones. Their expression is induced in response to a wide variety of physiological and environmental insults including anti-cancer chemotherapy, thus allowing the cell to survive to lethal conditions. Different functions of HSPs have been described to account for their cytoprotective function, including their role as molecular chaperones as they play a central role in the correct folding of misfolded proteins, but also their anti-apoptotic properties. HSPs are often overexpressed in cancer cells and this constitutive expression is necessary for cancer cells' survival. HSPs may have oncogene-like functions and likewise mediate "non-oncogene addiction" of stressed tumor cells that must adapt to a hostile microenvironment, thereby becoming dependent for their survival on HSPs. HSP-targeting drugs have therefore emerged as potential anti-cancer agents. This review describes the different molecules and approaches being used or proposed in cancer therapy based on the in inhibition of HSP90, HSP70 and HSP27.

A novel quinone-based derivative (DTNQ-Pro) induces apoptotic death via modulation of heat shock protein expression in Caco-2 cells

BACKGROUND AND PURPOSE

The resistance of human colon adenocarcinoma cells to antineoplastic agents may be related to the high endogenous expression of stress proteins, including the family of heat shock proteins (HSPs). Recently, a quinone-based pentacyclic derivative, DTNQ-Pro, showed high cytotoxic activity in human colon carcinoma cell lines. The aim of the present study was to determine the precise cellular mechanisms of this cytotoxic action of DTNQ-Pro.

EXPERIMENTAL APPROACH

Using human colorectal carcinoma-derived Caco-2 cells as a model, we studied the effects of DTNQ-Pro on cellular viability and oxidative stress; HSP70 and HSP27 accumulation; and cell cycle, differentiation and apoptosis.

KEY RESULTS

Incubation of Caco-2 cells with DTNQ-Pro reduced cell growth and increased the levels of reactive oxygen species in mitochondria. After 48 h of treatment, cells surviving showed an increased expression of Mn-superoxide dismutase (SOD), nitric oxide production and membrane lipid peroxidation. Treatment with DTNQ-Pro decreased HSP70 expression, and redistributed HSP27 and vimentin within the cell. DTNQ-Pro down-regulated the expression of A and B cyclins with arrest of the cell cycle in S phase and increased cellular differentiation. A second treatment of Caco-2 cells with DTNQ-Pro induced cellular death by activation of the apoptotic pathway.

CONCLUSIONS AND IMPLICATIONS

DTNQ-Pro causes Caco-2 cell death by induction of apoptosis via inhibition of HSP70 accumulation and the intracellular redistribution of HSP27. These findings suggest the potential use of DTNQ-Pro in combination chemotherapy for colon cancer.

ER stress and hormetic regulation of the aging process

An ability to mount a stress resistance under pressure is a major host defence mechanism and has been a fundamental force during evolution. However, the adaptation capacity clearly declines during aging and this loss of stress resistance accelerates the aging process exposing the organism to degenerative diseases. The effect of stress on organisms seems to be a dose-dependent response, i.e. mild stress induces a stress tolerance and extends the lifespan whereas excessive stress accentuates the aging process. This paradox is known as hormesis in aging research. It is essential to distinguish the intensity of cellular stress and thus mount an appropriate host defence. The endoplasmic reticulum (ER) contains three branches of stress transducers, i.e. IRE1, PERK, and ATF6 pathways, all of which recognize stress-related disturbances in the function of ER. These transducers trigger a complex signaling network which activates an unfolded protein response (UPR). Interestingly, ER stress transducers can distinguish the intensity of ER stress and induce a dose-dependent UPR, either adaptive response to stress or apoptotic cell death. The efficiency of the stress recognition system and UPR signaling declines during aging. We will discuss the role of ER stress in hormetic regulation of aging process and longevity.

Immunomodulatory effects of radiofrequency ablation in a breast cancer model

Radiofrequency ablation (RFA), a minimally invasive surgical procedure has an increasing application in the surgical treatment of tumors. Data indicate that RFA might stimulate anti-cancer immunity possibly through the induction of necrosis and heat shock proteins (HSP) expression. This study tests a hypothesis that RFA leads to bidirectional immunoregulation. Experimental rat breast tumors were treated with RFA, surgical excision or sham operation. RFA resulted in the highest NK cells infiltration, increased HSP70 expression and activation of caspase-3 enzyme in the tumor margins. A significant reduction of the circulatory regulatory T (Treg) cells was found in both RFA- and excision-treated rats, although less pronounced in the RFA-group. The splenocyte proliferation to tumor cell lysate was stronger in the RFA-treated rats in comparison with untreated tumor-bearing rats. The potential role of self-HSP for immunomodulation was examined using in vitro proliferation assay to tetanus toxoid using human peripheral leukocytes. The response to the tetanus toxoid was significantly suppressed by HSP90 plus auto-antibodies versus HSP90 or auto-antibodies alone. In conclusion, RFA reduced the circulatory Tregs although not as efficient as tumor excision. HSPs plus natural antibodies suppress the anti-tumor response probably by stimulating Tregs. Therefore, RFA may play a role in anti-cancer therapy if combined with Tregs suppression.

DNAJB6 induces degradation of beta-catenin and causes partial reversal of mesenchymal phenotype

We showed that expression of MRJ (DNAJB6) protein is lost in invasive ductal carcinoma, and restoration of MRJ(L) restricts malignant behavior of breast cancer and melanoma cells. However, the signaling pathways influenced by MRJ(L) are largely unknown. Our observations revealed that MRJ(L) expression causes changes in cell morphology concomitant with down-regulation of several mesenchymal markers, viz. vimentin, N-cadherin, Twist, and Slug, and up-regulation of epithelial marker keratin 18. Importantly, MRJ(L) expression led to reduced levels of beta-catenin, an epithelial mesenchymal transition marker, and a critical player in the Wnt pathway. We found that MRJ(L) up-regulates expression of DKK1, a well known Wnt/beta-catenin signaling inhibitor, that causes degradation of beta-catenin. Re-expression of DNAJB6 alters the Wnt/beta-catenin signaling in cancer cells, leading to partial reversal of the mesenchymal phenotype. Thus, MRJ(L) may play a role in maintaining an epithelial phenotype, and inhibition of the Wnt/beta-catenin pathway may be one of the potential mechanisms contributing to the restriction of malignant behavior by MRJ(L).

Quercetin suppresses HeLa cell viability via AMPK-induced HSP70 and EGFR down-regulation

Quercetin, an anti-oxidant flavonoid that is widely distributed in the plant kingdom, has been suggested to have chemopreventive effects on cancer cells, although the mechanism is not completely understood. In this study, we found that quercetin increased the phosphorylation of AMP-activated protein kinase (AMPK) and downstream acetyl-CoA carboxylase (ACC) and suppressed the viability of HeLa cells. AICAR, an AMPK activator, and quercetin down-regulated heat shock protein (HSP)70 and increased the activity of the pro-apoptotic effector, caspase 3. Knock-down of AMPK blocked quercetin-mediated HSP70 down-regulation. Moreover, knock-down of HSP70 enhanced quercetin-mediated caspase 3 activation. Furthermore, quercetin sustained epidermal growth factor receptor (EGFR) activation by suppressing the phosphatases, PP2a and SHP-2. Finally, quercetin increased the interaction between EGFR and Cbl, and also induced the tyrosine phosphorylation of Cbl. Together, these results suggest that quercetin may have anti-tumor effects on HeLa cells via AMPK-induced HSP70 and down-regulation of EGFR.

Ischemic postconditioning may not influence early brain injury induced by focal cerebral ischemia/reperfusion in rats

Background

Experimental studies have shown that ischemic postconditioning can reduce neuronal injury in the setting of cerebral ischemia, but the mechanisms are not yet clearly elucidated. This study was conducted to determine whether ischemic postconditioning can alter expression of heat shock protein 70 and reduce acute phase neuronal injury in rats subjected to transient focal cerebral ischemia/reperfusion.

Methods

Focal cerebral ischemia was induced by intraluminal middle cerebral artery occlusion for 60 min in twenty male Sprague-Dawley rats (250-300 g). Rats were randomized into control group and an ischemic postconditioning group (10 rats per group). The animals of control group had no intervention either before or after MCA occlusion. Ischemic postconditioning was elicited by 3 cycles of 30 s reperfusion interspersed by 10 s ischemia immediately after onset of reperfusion. The infarct ratios, brain edema ratios and motor behavior deficits were analyzed 24 hrs after ischemic insult. Caspase-3 reactive cells and cells showing heat shock protein 70 activity were counted in the caudoputamen and frontoparietal cortex.

Results

Ischemic postconditiong did not reduce infarct size and brain edema ratios compared to control group. Neurologic scores were not significantly different between groups. The number of caspase-3 reactive cells in the ischemic postconditioning group was not significantly different than the value of the control group in the caudoputamen and frontoparietal cortex. The number of cells showing heat shock protein 70 activity was not significantly different than the control group, as well.

Conclusions

These results suggest that ischemic postconditioning may not influence the early brain damage induced by focal cerebral ischemia in rats.

AIRAP, a new human heat shock gene regulated by heat shock factor 1

Heat shock factor-1 (HSF1) is the central regulator of heat-induced transcriptional responses leading to rapid expression of molecular chaperones that protect mammalian cells against proteotoxic stress. The main targets for HSF1 are specific promoter elements (HSE) located upstream of heat shock genes encoding a variety of heat shock proteins, including HSP70, HSP90, HSP27, and other proteins of the network. Herein we report that the zinc finger AN1-type domain-2a gene, also known as AIRAP, behaves as a canonical heat shock gene, whose expression is temperature-dependent and strictly controlled by HSF1. Transcription is triggered at temperatures above 40 degrees C in different types of human cancer and primary cells, including peripheral blood monocytes. As shown by ChIP analysis, HSF1 is recruited to the AIRAP promoter rapidly after heat treatment, with a kinetics that parallels HSP70 promoter HSF1-recruitment. In transfection experiments HSF1-silencing abolished heat-induced AIRAP promoter-driven transcription, which could be rescued by exogenous Flag-HSF1 expression. The HSF1 binding HSE sequence in the AIRAP promoter critical for heat-induced transcription was identified. Because its expression is induced at febrile temperatures in human cells, AIRAP may represent a new potential component of the protective response during fever in humans.

Cellular stress responses: cell survival and cell death

Cells can respond to stress in various ways ranging from the activation of survival pathways to the initiation of cell death that eventually eliminates damaged cells. Whether cells mount a protective or destructive stress response depends to a large extent on the nature and duration of the stress as well as the cell type. Also, there is often the interplay between these responses that ultimately determines the fate of the stressed cell. The mechanism by which a cell dies (i.e., apoptosis, necrosis, pyroptosis, or autophagic cell death) depends on various exogenous factors as well as the cell's ability to handle the stress to which it is exposed. The implications of cellular stress responses to human physiology and diseases are manifold and will be discussed in this review in the context of some major world health issues such as diabetes, Parkinson's disease, myocardial infarction, and cancer.

Dynamic proteomic overview of glioblastoma cells (A172) exposed to perillyl alcohol

Perillyl alcohol (POH) is a naturally occurring terpene and a promising chemotherapeutic agent for glioblastoma multiform; yet, little is known about its molecular effects. Here we present results of a semi-quantitative proteomic analysis of A172 cells exposed to POH for different time-periods (1', 10', 30', 60', 4h, and 24h). The analysis identified more than 4000 proteins; which were clustered using PatternLab for proteomics and then linked to Ras signaling, tissue homeostasis, induction of apoptosis, metallopeptidase activity, and ubiquitin-protein ligase activity. Our results make available one of the most complete protein repositories for the A172. Moreover, we detected the phosphorylation of GSK3beta (Glycogen synthase kinase) and the inhibition of ERK's (extracellular signal regulated kinase) phosphorylation after 10', which suggests a new mechanism of POH's activation for apoptosis.

Mesenchymal stem cells pretreated with delivered Hph-1-Hsp70 protein are protected from hypoxia-mediated cell death and rescue heart functions from myocardial injury

Mesenchymal stem cell (MSC) therapy for myocardial injury has inherent limitations due to the poor viability of MSCs after cell transplantation. In this study, we directly delivered Hsp70, a protein with protective functions against stress, into MSCs, using the Hph-1 protein transduction domain ex vivo for high transfection efficiency and low cytotoxicity. Compared to control MSCs in in vitro hypoxic conditions, MSCs delivered with Hph-1-Hsp70 (Hph-1-Hsp70-MSCs) displayed higher viability and anti-apoptotic properties, including Bcl2 increase, reduction of Bax, JNK phosphorylation and caspase-3 activity. Hsp70 delivery also attenuated cellular ATP-depleting stress. Eight animals per group were used for in vivo experiments after occlusion of the left coronary artery. Transplantation of Hph-1-Hsp70-MSCs led to a decrease in the fibrotic heart area, and significantly reduced the apoptotic positive index by 19.5 +/- 2%, compared to no-treatment controls. Hph-1-Hsp70-MSCs were well-integrated into the infarcted host myocardium. The mean microvessel count per field in the infarcted myocardium of the Hph-1-Hsp70-MSC-treated group (122.1 +/- 13.5) increased relative to the MSC-treated group (75.9 +/- 10.4). By echocardiography, transplantation of Hph-1-Hsp70-MSCs resulted in additional increases in heart function, compared to the MSCs-transplanted group. Our results may help formulate better clinical strategies for in vivo MSC cell therapy for myocardial damage.

Stress responses and conditioning effects in mesothelial cells exposed to peritoneal dialysis fluid

Renal replacement therapy by peritoneal dialysis is frequently complicated by technical failure. Peritoneal dialysis fluids (PDF) cause injury to the peritoneal mesothelial cell layer due to their cytotoxicity. As only isolated elements of the involved cellular processes have been studied before, we aimed at a global assessment of the mesothelial stress response to PDF. Following single or repeated exposure to PDF or control medium, proteomics and bioinformatics techniques were combined to study effects in mesothelial cells (MeT-5A). Protein expression was assessed by two-dimensional gel electrophoresis, and significantly altered spots were identified by MALDI-TOF MS and MS2 techniques. The lists of experimentally derived candidate proteins were expanded by a next neighbor approach and analyzed for significantly enriched biological processes. To address the problem of an unknown portion of false positive spots in 2DGE, only proteins showing significant p-values on both levels were further interpreted. Single PDF exposure resulted in reduction of biological processes in favor of reparative responses, including protein metabolism, modification and folding, with chaperones as a major subgroup. The observed biological processes triggered by this acute PDF exposure mainly contained functionally interwoven multitasking proteins contributing as well to cytoskeletal reorganization and defense mechanisms. Repeated PDF exposure resulted in attenuated protein regulation, reflecting inhibition of stress responses by high levels of preinduced chaperones. The identified proteins were less attributable to acute cellular injury but rather to specialized functions with a reduced number of involved multitasking proteins. This finding agrees well with the concept of conditioning effects and cytoprotection. In conclusion, this study describes the reprogrammed proteome of mesothelial cells during recovery from PDF exposure and adaption to repetitive stress. A broad stress response with a number of highly overlapping processes and multitasking proteins shifts toward a more specific response of only few less overlapping processes.

From mini-invasive to non-invasive treatment using monopolar radiofrequency: the next orthopaedic frontier

Tendinopathy arises from a failed tendon healing process. Current non-invasive therapeutic alternatives are anti-inflammatory in nature, and outcomes are unpredictable. The benefit of invasive alternatives resides in the induction of the healing response. A new technology that uses non-invasive monopolar capacitive coupled radiofrequency has demonstrated the ability to raise temperatures in tendons and ligaments above 50 degrees C, the threshold for collagen modulation, tissue shrinkage and recruitment of macrophages, fibroblasts, and heat shock protein factors, without damaging the overlying structures, resulting in activation of the wound healing response. Monopolar capacitive-coupled radiofrequency offers a new non-invasive choice for tendinopathies and sprained ligaments. It does not interfere with subsequent surgical procedures should they become necessary.

The role of lysosomal rupture in neuronal death

Apoptosis research in the past two decades has provided an enormous insight into its role in regulating cell death. However, apoptosis is only part of the story, and inhibition of neuronal necrosis may have greater impact than apoptosis, on the treatment of stroke, traumatic brain injury, and neurodegenerative diseases. Since the "calpain-cathepsin hypothesis" was first formulated, the calpain- and cathepsin-mediated regulation of necrotic cascades observed in monkeys, has been demonstrated to be a common neuronal death mechanism occurring from simpler organisms to humans. However, the detailed mechanism inducing lysosomal destabilization still remains poorly understood. Heat-shock protein-70 (Hsp70) is known to stabilize lysosomal membrane and protect cells from oxidative stress and apoptotic stimuli in many cell death pathways. Recent proteomics approach comparing pre- and post-ischemic hippocampal CA1 neurons as well as normal and glaucoma-suffered retina of primates, suggested that the substrate protein upon which activated calpain acts at the lysosomal membrane of neurons might be Hsp70. Understanding the interaction between activated calpains and Hsp70 will help to unravel the mechanism that destabilizes the lysosomal membrane, and will provide new insights into clarifying the whole cascade of neuronal necrosis. Although available evidence is circumferential, it is hypothesized that activated calpain cleaves oxidative stress-induced carbonylated Hsp70.1 (a major human Hsp70) at the lysosomal membrane, which result in lysosomal rupture/permeabilization. This review aims at highlighting the possible mechanism of lysosomal rupture in neuronal death by a modified "calpain-cathepsin hypothesis". As the autophagy-lysosomal degradation pathway is a target of oxidative stress, the implication of autophagy is also discussed.

Reinvestigation of the effect of carbenoxolone on the induction of heat shock proteins

Carbenoxolone (CBX) is a semisynthetic derivative of the licorice root substance glycyrrhizinic acid and has been previously reported to induce only heat shock protein 70 [Hsp70, HSPA1A (the systematic name of heat shock protein is given in the parenthesis after each HSP, according to the recent nomenclature guidelines, Kampinga et al., Cell Stress Chaperones, 14:105-111, 2008) but not other heat shock proteins (HSPs) (Nagayama et al., Life Sci. 69:2867-2873, 2001). In this study, we reinvestigated the effect of CBX on the induction of HSPs in HeLa and human neuroblastoma (A-172) cells. CBX clearly induced not only Hsp70 but also Hsp90 (HSPC1), Hsp40 (DNAJB1), and Hsp27 (HSPB1) at concentrations of 10 to 800 microM for 16 h incubation. At higher concentrations (more than 400 microM), however, CBX appeared to be toxic. Treatment of cells with CBX resulted in enhanced phosphorylation and acquisition of DNA-binding ability of heat shock transcription factor 1 (HSF1). Furthermore, characteristic HSF1 granules were formed in the nucleus, suggesting that the induction of HSPs by CBX is mediated by the activation of HSF1. Furthermore, thermotolerance was induced by CBX treatment, as determined by clonogenic survival. Although the precise target of CBX is not known at present, these results indicate that CBX is one of the molecular chaperone inducers and suggest that some pharmacological activities of CBX might be ascribable in part to its molecular chaperone-inducing property.

Peripheral leukocyte response to oncological radiotherapy: Expression of heat shock proteins

PURPOSE

To study Heat Shock Proteins (HSP) expression in patients subjected to radiotherapy and their potential use as biomarkers for radiation tolerance. An evaluation is also made of whether irradiated volume is critical to the outcome of normal tissue injury using polymorphonuclear neutrophils as biosensors, and whether HSP antibodies (Ab) may be involved in post-radiotherapy disease.

MATERIAL AND METHODS

Twelve patients receiving the same total dose of radiotherapy, but in three different volumes, and four healthy volunteers used as controls were analysed. hsp27 and 70i mRNA were determined by Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and Southern-blot, HSP by flow cytometry, and HSP-Ab by Enzyme-linked Immnoadsorbent Assay (ELISA). The clinical protocol included radiation related toxicity based on clinical and analytical scales.

RESULTS

Radiotherapy caused hsp downregulation, maximum in patients with the largest irradiated volumes, and a decrease in intracellular HSP content. Patients with greatest intraleukocyte HSP levels before treatment suffered more severe radiation morbidity. Patients with endocrine neoplasms presented the highest HSP-Ab titers.

CONCLUSIONS

Radiotherapy downregulates hsp27 and 70i, which would enhance radiosensitivity. HSP content prior to treatment is suggested as a prognostic biomarker for radiation tolerance, with circulating leukocytes as biosensors. HSP-Ab may be biomarkers of tumor disease, but do not seem to be involved in the morbidity of acute post-radiotherapy disease, which is closely related to the volumes irradiated.

HspBP1 levels are elevated in breast tumor tissue and inversely related to tumor aggressiveness

HspBP1 is a co-chaperone that binds to and regulates the chaperone Hsp70 (Hsp70 is used to refer to HSPA1A and HSPA1B). Hsp70 is known to be elevated in breast tumor tissue, therefore the purpose of these studies was to quantify the expression of HspBP1 in primary breast tumors and in serum of these patients with a follow-up analysis after 6 to 7 years. Levels of HspBP1, Hsp70, and anti-HspBP1 antibodies in sera of breast cancer patients and healthy individuals were measured by enzyme-linked immunosorbent assay. Expression of HspBP1 was quantified from biopsies of tumor and normal breast tissue by Western blot analysis. The data obtained were analyzed for association with tumor aggressiveness markers and with patient outcome. The levels of HspBP1 and Hsp70 were significantly higher in sera of patients compared to sera of healthy individuals. HspBP1 antibodies did not differ significantly between groups. HspBP1 levels were significantly higher in tumor (14.46 ng/microg protein, n = 51) compared to normal adjacent tissue (3.17 ng/microg protein, n = 41, p < 0.001). Expression of HspBP1 was significantly lower in patients with lymph node metastasis and positive for estrogen receptors. HspBP1 levels were also significantly lower in patients with a higher incidence of metastasis and death following a 6 to 7-year follow-up. The HspBP1/Hsp70 molar ratio was not associated with the prognostic markers analyzed. Our results indicate that low HspBP1 expression could be a candidate tumor aggressiveness marker.

Multi-faceted role of HSP40 in cancer

HSP40 (DNAJ) is an understudied family of co-chaperones. The human genome codes for over 41 members of HSP40 family that reside at distinct intracellular locations. Despite their large numbers, little is known about their physiologic roles. Recent research has revealed involvement of some of the DNAJ family members in various types of cancers. In this article we summarize the information about the involvement of human DNAJ family members in various aspects of cancer biology. Furthermore we discuss the potential role of the J domain of DNAJ proteins in cancer biology.

The HSP72 stress response of monocytes from patients on haemodialysis is impaired

BACKGROUND

Induction of heat shock proteins (HSP), i.e. of the major family member HSP70, is an important cytoprotective-resistance mechanism for monocytes/ macrophages (Mphi). Patients on haemodialysis present with a high infectious morbidity and enhanced carcinoma incidence. Renal insufficiency-related alteration of microbicidal and tumoricidal functions of Mphi, major effectors of the immune system, might promote these diseases.

METHODS

Freshly isolated Mphi from Sprague-Dawley rats 2 weeks after 5/6-nephrectomy and from patients on intermittent haemodialysis (IHD) were stimulated by heat shock (HS) and compared to stimulated Mphi of control rats or healthy volunteers (CTR). Expression of HSP72 (inducible HSP70) was assessed by RT-PCR, and/or flow cytometry. Apoptosis of Mphi was detected by flow cytometry (CD14/annexin V-labelling).

RESULTS

In rat Mphi, baseline HSP72 expression was similar in both groups, but its induction was significantly impaired in renal insufficiency (214 +/- 68% less HSP70-mRNA versus CTR, n = 6). In patients, HSF-1-mRNA and HSP72-mRNA/protein response to HS was significantly lower, but not affected by dialysis session itself. In parallel, apoptosis of Mphi of patients was enhanced (+83 +/- 29% constitutive apoptotic Mphi versus CTR, n = 8), and HS-dependent protection from apoptosis with and without serum depletion (48 h depletion: HS, +275 +/- 37% apoptotic Mphi versus CTR, n = 6; full medium: +166 +/- 62% versus CTR, n = 8, P < 0.05) was inferior.

CONCLUSIONS

Impaired HSP72 stress response of Mphi in patients on haemodialysis might contribute to the observed immune dysfunction and, therefore, to the increased susceptibility to infection and malignancy. Stress impairment is not restricted to uraemia but is already present in a rat model of chronic kidney disease.

Expression of heat shock protein 105 and 70 in malignant melanoma and benign melanocytic nevi

BACKGROUND

Heat shock proteins (HSPs) restore immature proteins or denatured proteins, thus protecting cells. Also, the expression of some HSPs is elevated substantially in malignant tumors, but the expression of HSPs in association with melanoma has yet to be studied. Therefore, we examined the expression patterns of HSP 70 and 105 in melanoma, benign melanocytic nevi and normal human skin.

METHODS

Two specimens of malignant melanoma, two of benign melanocytic nevi and six of normal human skin were analyzed using Western blot analysis for expression of HSP 70 and 105. In another set, 16 specimens of malignant melanoma, 24 of benign melanocytic nevi and eight of normal human skin were analyzed for the expression of HSP 105 using immunohistochemical studies.

RESULTS

The Western blot analysis showed that HSP 70 was overexpressed in all three types. But, the HSP 105 was hardly expressed in normal human skin and benign melanocytic nevi. However, in malignant melanoma, the HSP 105 was overexpressed, and immunohistochemical examination of HSP 105 showed a result similar to that of Western blot analysis.

CONCLUSIONS

In our study, HSP 105 is thought to be a more relevant tumor-associated antigen in malignant melanoma than is HSP 70.

Heat shock proteins and immune system

Heat shock proteins (HSPs) such as HSP 60 (Hsp60), Hsp70, Hsp90, and gp96, have been reported to play important roles in antigen presentation and cross-presentation, activation of macrophages and lymphocytes, and activation and maturation of dendritic cells. HSPs contain peptide-binding domains that bind exposed hydrophobic residues of substrate proteins. As part of their molecular chaperone functions, HSPs bind and deliver chaperoned, antigenic peptides to MHC class I molecules at the cell surface for presentation to lymphocytes. HSPs also bind nonprotein molecules with exposed hydrophobic residues including lipid-based TLR ligands. Recombinant HSP products may be contaminated with pathogen-associated molecules that contain exposed hydrophobic residues such as LPS (a TLR4 ligand), lipoprotein (a TLR2 ligand), and flagellin (a TLR5 ligand). These contaminants appear to be responsible for most, if not all, reported in vitro cytokine effects of HSPs, as highly purified HSPs do not show any cytokine effects. We propose that HSPs are molecular chaperones that bind protein and nonprotein molecules with exposed hydrophobic residues. The reported antigen presentation and cross-presentation and in vitro HSP cytokine functions are a result of molecules bound to or chaperoned by HSPs but not a result of HSPs themselves.

HSP70 is associated with endothelial activation in placental vascular diseases

Endothelial cell injury and activation in the placenta are features of placental vascular disease (PVD). While advances in PVD have been made, the pathogenesis of this disease is still unknown. The objective of this study was to pursue potential risk factors and signal transcription pathways involved in PVD pathogenesis. Gene expression in subjects with PVD and with normal pregnancies was compared using a two-channel microarray technique. Higher expression of HSPA6 and HSPA1A was exhibited in PVD subjects. HSPA6 and HSPA1A both encode HSP70, and, therefore, we localized HSP70 expression in placental tissue. Using quantitative polymerase chain reaction (PCR) and Western blot, we observed a significant upregulation of HSP70 in both mRNA and protein levels in placental tissue and microvascular endothelial cells of PVD subjects when compared with normal pregnancies (P< 0.05). HSP70 mRNA and protein expression also correlated negatively with infant birth weight (P< 0.05). HSP70 was expressed mainly in endothelial cells and smooth muscle cells in the placental microvessels. We therefore conclude that HSP70 may mediate endothelial activation and play a role in pathogenesis of PVD.

Lysosomal involvement in cell death and cancer

Lysosomes, with their arsenal of degradative enzymes are increasingly becoming an area of interest in the field of oncology. The changes induced in this compartment upon transformation are numerous and whereas most are viewed as pro-oncogenic the same processes also render cancer cells susceptible to lysosomal death pathways. This review will provide an overview of the pro- and anti-oncogenic potential of this compartment and how these might be exploited for cancer therapy, with special focus on lysosomal death pathways.

A heat shock protein gene (Hsp70.1) is critically involved in the generation of the immune response to myelin antigen

Protracted inflammation has been associated with the generation of autoimmune responses. In this respect, increase in the chaperonin, heat shock protein 70 (hsp70) is an outcome of prolonged inflammatory stress. Previous experiments have shown that overexpression of inducible hsp70 in vitro enhanced myelin autoantigen recognition. To prove the role of hsp70 in myelin-directed responses in vivo, we applied a mouse deficient in the major gene encoding inducible hsp70, hsp70.1. Hsp70.1(-/-) mice sensitized for experimental autoimmune encephalomyelitis (EAE) with myelin oligodendrocyte glycoprotein (MOG) peptide 35-55, displayed almost complete resistance to the disease. This correlated with the loss of T cell proliferation and IFN-gamma production in response to MOG(35-55). T cell transfer experiments as well as antigen presentation assays in vitro demonstrated that hsp70 deficiency was associated with dysfunction in the activation of autoreactive T cells. Moreover, T cell responses to ovalbumin (OVA) peptide 323-339 were altered and CD4(+) T cells were more prone to TCR-induced apoptosis, suggesting broader spectrum of T cell defect in hsp70.1(-/-) mice. These results provide compelling evidence for generalized effect mediated by inducible hsp70 in the recognition of myelin self and non-self antigens that influences the cytokine profile of the immune response affecting autoimmune demyelination.