Heat shock protein-60 expression was significantly correlated with the prognosis of lung adenocarcinoma

Dihydrotanshinone I potentiates the anti-tumor activity of cisplatin by activating ROS-mediated ER stress through targeting HSPD1 in lung cancer cells

Lung cancer represents one of the most lethal malignancies, characterized by the highest incidence and mortality rates globally. Cisplatin-based chemotherapy exerts powerful anti-tumor activities in lung cancer, whereas its clinical application was limited due to the severe side effects. Dihydrotanshinone I (DHTS), a root extract from Salvia miltiorrhiza, exhibits diverse biological functions, encompassing liver protection, anti-inflammatory properties, promotion of osteoclast differentiation, and induction of apoptosis in tumor cells. DHTS exerts anti-tumor effects in various cancers, however, its biological functions in lung cancer are largely unknown. We demonstrated that DHTS synergistically increased the tumor suppressive effects of cisplatin in lung cancer cells by activating reactive oxygen species (ROS)-mediated endoplasmic reticulum stress (ER stress) and c-Jun N-terminal kinase (JNK) signaling pathways, both in vitro and in vivo. Additionally, DHTS induced excessive ROS accumulation by inhibiting the expression of Heat Shock Proteins 60 (HSPD1). Silencing HSPD1 augmented the anti-tumor effects of DHTS in lung cancer cells, primarily through the stimulation of ROS-mediated ER stress and JNK pathways. Our study suggests that DHTS possesses druggable potential, and combined therapy with DHTS and cisplatin may be a promising therapeutic strategy for certain lung cancer patients.

Anticarcinogenic Effects of Gold Nanoparticles and Metformin Against MCF-7 and A549 Cells

Metformin is commonly prescribed to people with diabetes. Metformin has been shown in previous studies to be able to prevent the growth of cancer cells. This study aims to investigate the effects of metformin and gold nanoparticles in MCF7 breast cancer and A549 lung cell lines. The effects of metformin and gold nanoparticles on MCF7 breast cancer and A549 lung cells were determined on cells grown in 24 h cell culture. MCF-7 and A549 cells were incubated for 24 h with the treatment of escalating molar concentrations of ifosfamide. The MTT assay was used to determine the cytotoxicity of metformin toward MCF7 and A549 cell lines. The expression of Bax, BCL2, PI3K, Akt3, mTOR, Hsp60, Hsp70, and TNF-α was measured by RT-PCR. Metformin and gold nanoparticles inhibited the proliferation of MCF-7 and A549 cells in a dose and time-dependent manner with an IC50 value of 5 µM and 10 µg/mL. RT-PCR assays showed ifosfamide + metformin + gold nanoparticles significantly reduced the expression of BCL2, PI3K, Akt3, mTOR, Hsp60 and Hsp70 and increased the expression of TNF-α and Bax. The findings obtained in this study suggest that further studies should be conducted, and metformin and gold nanoparticles can be used in breast cancer and lung cancer treatments.

Knockdown of heat shock protein family D member 1 (HSPD1) in lung cancer cell altered secretome profile and cancer-associated fibroblast induction

The crosstalk between lung cancer cells and cancer-associated fibroblast (CAF) is pivotal in cancer progression. Heat shock protein family D member 1 (HSPD1) is a potential prognostic biomarker associated with the tumor microenvironment in lung adenocarcinoma (LUAD). However, the role of HSPD1 in CAF activation remains unclear. This study established stable HSPD1-knockdown A549 lung cancer cells using a lentivirus-mediated shRNA transduction. A targeted label-free proteomic analysis identified six significantly altered secretory proteins in the shHSPD1-A549 secretome compared to shControl-A549. Functional enrichment analysis highlighted their involvement in cell-to-cell communication and immune responses within the tumor microenvironment. Additionally, most altered proteins exhibited positive correlations and significant prognostic impacts on LUAD patient survival. Investigations on the effects of lung cancer secretomes on lung fibroblast WI-38 cells revealed that the shControl-A549 secretome stimulated fibroblast proliferation, migration, and CAF marker expression. These effects were reversed upon the knockdown of HSPD1 in A549 cells. Altogether, our findings illustrate the role of HSPD1 in mediating CAF induction through secretory proteins, potentially contributing to the progression and aggressiveness of lung cancer.

Potential association of HSPD1 with dysregulations in ribosome biogenesis and immune cell infiltration in lung adenocarcinoma: An integrated bioinformatic approach

BACKGROUND

Lung adenocarcinoma (LUAD) is a major histological subtype of lung cancer with a high mortality rate worldwide. Heat shock protein family D member 1 (HSPD1, also known as HSP60) is reported to be increased in tumor tissues of lung cancer patients compared with healthy control tissues.

OBJECTIVE

We aimed to investigate the roles of HSPD1 in prognosis, carcinogenesis, and immune infiltration in LUAD using an integrative bioinformatic analysis.

METHODS

HSPD1 expression in LUAD was investigated in several transcriptome-based and protein databases. Survival analysis was performed using the KM plotter and OSluca databases, while prognostic significance was independently confirmed through univariate and multivariate analyses. Integrative gene interaction network and enrichment analyses of HSPD1-correlated genes were performed to investigate the roles of HSPD1 in LUAD carcinogenesis. TIMER and TISIDB were used to analyze correlation between HSPD1 expression and immune cell infiltration.

RESULTS

The mRNA and protein expressions of HSPD1 were higher in LUAD compared with normal tissues. High HSPD1 expression was associated with male gender and LUAD with advanced stages. High HSPD1 expression was an independent prognostic factor associated with poor survival in LUAD patients. HSPD1-correlated genes with prognostic impact were mainly involved in aberrant ribosome biogenesis, while LUAD patients with high HSPD1 expression had low tumor infiltrations of activated and immature B cells and CD4+ T cells.

CONCLUSIONS

HSPD1 may play a role in the regulation of ribosome biogenesis and B cell-mediated immunity in LUAD. It could serve as a predictive biomarker for prognosis and immunotherapy response in LUAD.

Construction of a prognostic model for lung adenocarcinoma based on heat shock protein-related genes and immune analysis

Lung adenocarcinoma (LUAD) represents a prevalent form of cancer, with low early diagnosis rates and high mortality rates, posing a global health challenge. Heat shock proteins (HSPs) assume a crucial role within the tumor immune microenvironment (TME) of LUAD. Here, a collection of 97 HSP-related genes (HSPGs) was assembled based on prior literature reports, of which 36 HSPGs were differentially expressed in LUAD. In The Cancer Genome Atlas (TCGA) cohort, we constructed a prognostic model for risk stratification and prognosis prediction by integrating 13 HSPGs. In addition, the prognostic significance and predictive efficacy of the HSP-related riskscore were examined and validated in the Gene Expression Omnibus (GEO) cohort. To facilitate the clinical use of this riskscore, we also established a nomogram scale by verifying its effectiveness through different methods. In light of these outcomes, we concluded a significant correlation between HSPs and TME in LUAD, and the riskscore can be a reliable prognostic indicator. Furthermore, this study evaluated the differences in immunophenoscore, tumor immune dysfunction and exclusion score, and sensitivity to several common chemotherapy drugs among LUAD individuals in different risk groups, which may aid in clinical decision-making for immune therapy and chemotherapy in LUAD individuals.

Heat Shock Proteins and HSF1 in Cancer

Fitness of cells is dependent on protein homeostasis which is maintained by cooperative activities of protein chaperones and proteolytic machinery. Upon encountering protein-damaging conditions, cells activate the heat-shock response (HSR) which involves HSF1-mediated transcriptional upregulation of a group of chaperones - the heat shock proteins (HSPs). Cancer cells experience high levels of proteotoxic stress due to the production of mutated proteins, aneuploidy-induced excess of components of multiprotein complexes, increased translation rates, and dysregulated metabolism. To cope with this chronic state of proteotoxic stress, cancers almost invariably upregulate major components of HSR, including HSF1 and individual HSPs. Some oncogenic programs show dependence or coupling with a particular HSR factor (such as frequent coamplification of HSF1 and MYC genes). Elevated levels of HSPs and HSF1 are typically associated with drug resistance and poor clinical outcomes in various malignancies. The non-oncogene dependence ("addiction") on protein quality controls represents a pancancer target in treating human malignancies, offering a potential to enhance efficacy of standard and targeted chemotherapy and immune checkpoint inhibitors. In cancers with specific dependencies, HSR components can serve as alternative targets to poorly druggable oncogenic drivers.

Hsp27 and Hsp60 in human submandibular salivary gland: Quantitative patterns in healthy and cancerous tissues with potential implications for differential diagnosis and carcinogenesis

Tumors of the submandibular salivary gland (SMG) are uncommon but sufficiently frequent for the physician to consider them in routine examinations and for the pathologist to be prepared to differentiate them from other tissue abnormalities. However, scarcity of specimens makes training difficult, a situation compounded by the lack of accepted universal diagnostic guidelines. Furthermore, there is little information on the chaperone system (CS) of the gland, despite the increasing evidence of its participation in carcinogenesis as a biomarker for diagnosis and patient follow up, and in the mechanisms by which the tumor cells thrive. We are investigating this aspect of various tumors, and here we describe standardized methods for assessing the tissue levels of two chaperones, Hsp27 and Hsp60, in normal SMG and its tumors. We present illustrative results obtained with immunohistochemistry (IHC) and immunofluorescence-confocal microscopy (IF-CM), which we propose as a platform onto which a data base could be built by adding new information and which would provide material for developing guidelines for tumor identification and monitoring. The initial findings are encouraging in as much as the tumors surveyed showed quantitative patterns of Hsp27 and Hsp60 that distinguished tumoral from normal tissue and certain tumors from the others, and the results from IHC were confirmed by IF-CM.

Recent advances in heat shock proteins in cancer diagnosis, prognosis, metabolism and treatment

Heat shock proteins (HSPs) are a group of proteins, also known as molecular chaperones, which participate in protein folding and maturation in response to stresses or high temperature. According to their molecular weights, mammalian HSPs are classified into HSP27, HSP40, HSP60, HSP70, HSP90, and large HSPs. Previous studies have revealed that HSPs play important roles in oncogenesis and malignant progression because they can modulate all six hallmark traits of cancer. Because of this, HSPs have been propelled into the spotlight as biomarkers for cancer diagnosis and prognosis, as well as an exciting anticancer drug target. However, the relationship between the expression level of HSPs and their activity and cancer diagnosis, prognosis, metabolism and treatment is not clear and has not been completely established. Herein, this review summarizes and discusses recent advances and perspectives in major HSPs as biomarkers for cancer diagnosis, as regulators for cancer metabolism or as therapeutic targets for cancer therapy, which may provide new directions to improve the accuracy of cancer diagnosis and develop more effective and safer anticancer therapeutics.

Metabolic impairment of non-small cell lung cancers by mitochondrial HSPD1 targeting

Background

The identification of novel targets is of paramount importance to develop more effective drugs and improve the treatment of non-small cell lung cancer (NSCLC), the leading cause of cancer-related deaths worldwide. Since cells alter their metabolic rewiring during tumorigenesis and along cancer progression, targeting key metabolic players and metabolism-associated proteins represents a valuable approach with a high therapeutic potential. Metabolic fitness relies on the functionality of heat shock proteins (HSPs), molecular chaperones that facilitate the correct folding of metabolism enzymes and their assembly in macromolecular structures.

Methods

Gene fitness was determined by bioinformatics analysis from available datasets from genetic screenings. HSPD1 expression was evaluated by immunohistochemistry from formalin-fixed paraffin-embedded tissues from NSCLC patients. Real-time proliferation assays with and without cytotoxicity reagents, colony formation assays and cell cycle analyses were used to monitor growth and drug sensitivity of different NSCLC cells in vitro. In vivo growth was monitored with subcutaneous injections in immune-deficient mice. Cell metabolic activity was analyzed through extracellular metabolic flux analysis. Specific knockouts were introduced by CRISPR/Cas9.

Results

We show heat shock protein family D member 1 (HSPD1 or HSP60) as a survival gene ubiquitously expressed in NSCLC and associated with poor patients’ prognosis. HSPD1 knockdown or its chemical disruption by the small molecule KHS101 induces a drastic breakdown of oxidative phosphorylation, and suppresses cell proliferation both in vitro and in vivo. By combining drug profiling with transcriptomics and through a whole-genome CRISPR/Cas9 screen, we demonstrate that HSPD1-targeted anti-cancer effects are dependent on oxidative phosphorylation and validated molecular determinants of KHS101 sensitivity, in particular, the creatine-transporter SLC6A8 and the subunit of the cytochrome c oxidase complex COX5B.

Conclusions

These results highlight mitochondrial metabolism as an attractive target and HSPD1 as a potential theranostic marker for developing therapies to combat NSCLC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-02049-8.

Exploiting the HSP60/10 chaperonin system as a chemotherapeutic target for colorectal cancer

Over the past few decades, an increasing variety of molecular chaperones have been investigated for their role in tumorigenesis and as potential chemotherapeutic targets; however, the 60 kDa Heat Shock Protein (HSP60), along with its HSP10 co-chaperone, have received little attention in this regard. In the present study, we investigated two series of our previously developed inhibitors of the bacterial homolog of HSP60/10, called GroEL/ES, for their selective cytotoxicity to cancerous over non-cancerous colorectal cells. We further developed a third "hybrid" series of analogs to identify new candidates with superior properties than the two parent scaffolds. Using a series of well-established HSP60/10 biochemical screens and cell-viability assays, we identified 24 inhibitors (14%) that exhibited > 3-fold selectivity for targeting colorectal cancer over non-cancerous cells. Notably, cell viability EC₅₀ results correlated with the relative expression of HSP60 in the mitochondria, suggesting a potential for this HSP60-targeting chemotherapeutic strategy as emerging evidence indicates that HSP60 is up-regulated in colorectal cancer tumors. Further examination of five lead candidates indicated their ability to inhibit the clonogenicity and migration of colorectal cancer cells. These promising results are the most thorough analysis and first reported instance of HSP60/10 inhibitors being able to selectively target colorectal cancer cells and highlight the potential of the HSP60/10 chaperonin system as a viable chemotherapeutic target.

Maf1 suppression of ATF5-dependent mitochondrial unfolded protein response contributes to rapamycin-induced radio-sensitivity in lung cancer cell line A549

mTOR is well known to promote tumor growth but its roles in enhancing chemotherapy and radiotherapy have not been well studied. mTOR inhibition by rapamycin can sensitize cancer cells to radiotherapy. Here we show that Maf1 is required for rapamycin to increase radio-sensitivity in A549 lung cancer cells. In response to ionizing radiation (IR), Maf1 is inhibited by Akt-dependent re-phosphorylation, which activates mitochondrial unfolded protein response (UPR^mt) through ATF5. Rapamycin suppresses IR-induced Maf1 re-phosphorylation and UPR^mt activation in A549 cells, resulting in increased sensitivity to IR-mediated cytotoxicity. Consistently, Maf1 knockdown activates ATF5-transcription of mtHSP70 and HSP60, enhances mitochondrial membrane potential, reduces intracellular ROS levels and dampens rapamycin's effect on increasing IR-mediated cytotoxicity. In addition, Maf1 overexpression suppresses ethidium bromide-induced UPR^mt and enhances IR-mediated cytotoxicity. Supporting our cell-based studies, elevated expression of UPR^mt makers (mtHSP70 and HSP60) are associated with poor prognosis in patients with lung adenocarcinoma (LAUD). Together, our study reveals a novel role of Maf1-UPR^mt axis in mediating rapamycin's enhancing effect on IR sensitivity in A549 lung cancer cells.

Heat shock proteins as biomarkers of lung cancer

Heat shock proteins are known to be associated with a wide variety of human cancers including lung cancer. Overexpression of these molecular chaperones is linked with tumor survival, metastasis and anticancer drug resistance. In recent years, heat shock proteins are gaining much importance in the field of cancer research owing to their potential to be key determinants of cell survival and apoptosis. Lung cancer is one of the most common cancers diagnosed worldwide and the association of heat shock proteins in lung cancer diagnosis, prognosis and as drug targets remains unresolved. The aim of this review is to draw the importance of heat shock protein members; Hsp27, Hsp70, Hsp90, Hsp60 and their diagnostic and prognostic implications in lung cancer. Based on the available literature heat shock proteins can serve as biomarkers and anticancer drug targets in the management of lung cancer patients.

Role of HSP60/HSP10 in Lung Cancer: Simple Biomarkers or Leading Actors?

Cancers are one of the major challenges faced by modern medicine both because of their impact in terms of the amount of cases and of the ineffectiveness of therapies used today. A concrete support to the fight against them can be found in the analysis and understanding of the molecular mechanisms involving molecular chaperones. In particular, HSP60 and HSP10 seem to play an important role in carcinogenesis, supporting tumours in their proliferation, survival, and metastasis. Efforts must be directed toward finding ways to eliminate or block this "mistaken" chaperone. Therefore, the scientific community must develop therapeutic strategies that consider HSP60 and HSP10 as the possible target of an anti-tumoural treatment and not only as diagnostic biomarkers, since they contribute to the evolution of pre-cancerous respiratory pathologies in lung tumours. HSP60 acts at the mitochondrial, cytoplasmic, and extracellular levels in the development of cancer pathologies. The molecular mechanisms in which these chaperones are involved concern cell survival, the restoration of a condition of absence of replicative senescence, the promotion of pro-inflammatory environments, and an increase in the ability to form metastases. In this review, we will also present examples of interactions between HSP60 and HSP10 and different molecules and ways to exploit this knowledge in anticancer therapies for lung tumours. In order to improve not only chances for an earlier diagnosis but also treatments for patients suffering from this type of disease, chaperones must be considered as key agents in carcinogenesis and primary targets in therapeutics.

2-Methoxyestradiol and Its Combination with a Natural Compound, Ferulic Acid, Induces Melanoma Cell Death via Downregulation of Hsp60 and Hsp90

Melanoma is an aggressive type of skin cancer with one of the highest mortality rates. Notably, its incidence in the last few decades has increased faster than any other cancer. Therefore, searching for novel anticancer therapies is of great clinical importance. In the present study, we investigated the anticancer potential of 2-methoxyestradiol, potent chemotherapeutic, in the A375 melanoma cellular model. In order to furthermore evaluate the anticancer efficacy of 2-methoxyestradiol, we have additionally combined the treatment with a naturally occurring polyphenol, ferulic acid. The results were obtained using the melanoma A375 cellular model. In the study, we used MTT assay, flow cytometry, and western blot techniques. Herein, we have evidenced that the molecular mechanism of action of 2-methoxyestradiol and ferulic acid is partly related to the reduction of Hsp60 and Hsp90 levels and the induction of nitric oxide in the A375 melanoma cell model, while no changes were observed in Hsp70 expression after 2-methoxyestradiol and ferulic acid treatment separately or in combination. This is especially important in case of chemoresistance mechanisms because the accumulation of Hsp70 reduces induction of cancer cell death, thus decreasing antitumour efficacy.

The Multiple Roles and Therapeutic Potential of Molecular Chaperones in Prostate Cancer

Prostate cancer (PCa) is one of the most common cancer types in men worldwide. Heat shock proteins (HSPs) are molecular chaperones that are widely implicated in the pathogenesis, diagnosis, prognosis, and treatment of many cancers. The role of HSPs in PCa is complex and their expression has been linked to the progression and aggressiveness of the tumor. Prominent chaperones, including HSP90 and HSP70, are involved in the folding and trafficking of critical cancer-related proteins. Other members of HSPs, including HSP27 and HSP60, have been considered as promising biomarkers, similar to prostate-specific membrane antigen (PSMA), for PCa screening in order to evaluate and monitor the progression or recurrence of the disease. Moreover, expression level of chaperones like clusterin has been shown to correlate directly with the prostate tumor grade. Hence, targeting HSPs in PCa has been suggested as a promising strategy for cancer therapy. In the current review, we discuss the functions as well as the role of HSPs in PCa progression and further evaluate the approach of inhibiting HSPs as a cancer treatment strategy.

Impact of Heat Shock Protein 90 Inhibition on the Proteomic Profile of Lung Adenocarcinoma as Measured by Two-Dimensional Electrophoresis Coupled with Mass Spectrometry

Heat shock protein 90 (HSP90) is an important chaperone in lung adenocarcinoma, with relevant protein drivers such as EGFR (epidermal growth factor receptor) and EML4-ALK (echinoderm microtubule-associated protein-like protein4 fused to anaplastic lymphoma kinase) depending on it for their correct function, therefore HSP90 inhibitors show promise as potential treatments for lung adenocarcinoma. To study responses to its inhibition, HSP90 was pharmacologically interrupted by geldanamycin and resorcinol derivatives or with combined inhibition of HSP90 plus HSP70 in lung adenocarcinoma cell lines. Two-dimensional electrophoresis was performed to identify proteomic profiles associated with inhibition which will help to understand the biological basis for the responses. HSP90 inhibition resulted in altered protein profiles that differed according the treatment condition studied. Results revealed 254 differentially expressed proteins after treatments, among which, eukaryotic translation initiation factor3 subunit I (eIF3i) and citrate synthase demonstrated their potential role as response biomarkers. The differentially expressed proteins also enabled signalling pathways involved in responses to be identified; these included apoptosis, serine-glycine biosynthesis and tricarboxylic acid cycle. The proteomic profiles identified here contribute to an improved understanding of HSP90 inhibition and open possibilities for the detection of potential response biomarkers which will be essential to maximize treatment efficacy in lung adenocarcinoma.

HSP60 silencing promotes Warburg-like phenotypes and switches the mitochondrial function from ATP production to biosynthesis in ccRCC cells

HSP60 is a major mitochondrial chaperone for maintaining mitochondrial proteostasis. Our previous studies showed that HSP60 was significantly downregulated in clear cell renal cell carcinoma (ccRCC), the most common type of kidney cancer characterized by the classic Warburg effect. Here, we analyzed datasets in The Cancer Genome Atlas and revealed that higher HSP60 expression correlated with better overall survival in ccRCC patients. We also stably knocked down or overexpressed HSP60 in ccRCC cells to investigate the effects of HSP60 expression on the transition between oxidative phosphorylation and glycolysis. We confirmed that HSP60 knockdown increased cell proliferation, whereas its overexpression decreased cell growth. Proteomics and metabolomics revealed that HSP60 knockdown promoted Warburg-like phenotypes with enhanced glycolysis and decreased mitochondrial activity. Consistent with this finding, isotope tracing showed that the metabolic flow from glycolysis to TCA was reduced. However, HSP60 silencing enhanced mitochondrial functions in glutamine-directed biosynthesis with increased flow in two parts of the TCA cycle: Gln→αKG→OAA→Asp and Gln→αKG→ISO→acetyl-CoA, resulting in elevated de novo nucleotide synthesis and lipid synthesis. Proteomic analysis indicated that HSP60 silencing activated NRF2-mediated oxidative stress responses, while glutamate generated from glutamine increased glutathione synthesis for quenching excessive reactive oxygen species (ROS) produced upon elevated cell growth. We further found that HSP60 silencing activated the MEK/ERK/c-Myc axis to promote glutamine addiction, and confirmed that ccRCC cells were susceptible to oxidative stress and glutaminase inhibition. Collectively, our data show that HSP60 knockdown drives metabolic reprogramming in ccRCC to promote tumor progression and enhances mitochondrial-dependent biosynthesis.

Isotope tracing assisted metabolic profiling: Application to understanding HSP60 silencing mediated tumor progression

Isotope-tracing facilitates the understanding of metabolic regulation in biological systems. Depending on the selection of tracers, some essential metabolites cannot be traced. A comprehensive understanding of the regulated pathways can only be achieved with focus beyond labeled metabolites. The isotope tracing assisted metabolic profiling described here is a platform for high throughput mapping of isotope labeled metabolites with simultaneous metabolomics profiling. This approach incorporates an in-house MS/MS library for metabolite identification and ID-based quantitation. An "Isotopic" software was developed to generate potential labeled isotopomers. Using this platform, a total of 394 metabolites were reliably identified based on MS/MS confirmation in 3 million 293 T cells, among which 54 and 43 metabolites were discovered to carry extensive labels (>2%) from ¹³C₆-glucose and ¹³C₅-glutamine respectively. Citrate flowing into malate shuttle was also observed. More interestingly, the rate-limiting step in NAD and UDP-GlcNAc biosynthesis was clearly observed according to time course labeling. In HSP60 knockdown cell lines, enhanced purine and pyrimidine biosynthesis were confirmed by the abundance and labeling percentages of intermediate metabolites.

Toward Developing Chemical Modulators of Hsp60 as Potential Therapeutics

The 60 kDa heat shock protein (Hsp60) is classically known as a mitochondrial chaperonin protein working together with co-chaperonin 10 kDa heat shock protein (Hsp10). This chaperonin complex is essential for folding proteins newly imported into mitochondria. However, Hsp60, and/or Hsp10 have also been shown to reside in other subcellular compartments including extracellular space, cytosol, and nucleus. The proteins in these extra-mitochondrial compartments may possess a wide range of functions dependent or independent of its chaperoning activity. But the mechanistic details remain unknown. Mutations in Hsp60 gene have been shown to be associated with neurodegenerative disorders. Abnormality in expression level and/or subcellular localization have also been detected from different diseased tissues including inflammatory diseases and various cancers. Therefore, there is a strong interest in developing small molecule modulators of Hsp60. Most of the reported inhibitors were discovered through various chemoproteomics strategies. In this review, we will describe the recent progress in this area with reported inhibitors from both natural products and synthetic compounds. The former includes mizoribine, epolactaene, myrtucommulone, stephacidin B, and avrainvillamide while the latter includes o-carboranylphenoxyacetanilides and gold (III) porphyrins. The potencies of the known inhibitors range from low micromolar to millimolar concentrations. The potential applications of these inhibitors include anti-cancer, anti-inflammatory diseases, and anti-autoimmune diseases.

Chaperonin (HSP60) and annexin-2 are candidate biomarkers for non-small cell lung carcinoma

BACKGROUND

Lung cancer is responsible of 12.4% and 17.6% of all newly diagnosed cancer cases and mortality due to cancer, respectively, and 5-year survival rate despite all improved treatment options is 15%. This survival rate reaches 66% in the Stage 1 and surgically treated patients. Early diagnosis which could not be definitely and commonly achieved yet is extremely critical in obtaining high survival rate in this disease. For this reason; proteomic differences were evaluated using matrix assisted laser desorption ionization (MALDI) mass spectrometry in the subgroups of lung adenocarcinoma and squamous cell carcinoma.

METHODS

Fresh tissue samples of 36 malignant cases involving 83.3% (n = 30) men and 16.7% (n = 6) women patients were distributed into 2 groups as early and end stage lung cancer and each group were composed of subgroups including 18 squamous cell carcinoma (9 early stage cases, 9 end stage cases) and 18 adenocarcinoma cases (9 early stage cases, 9 end stage cases). The fresh tissues obtained from the tumoral and matched normal sites after surgical intervention. The differences in protein expression levels were determined by comparing proteomic changes in each patient.

RESULTS

In the subgroups of advanced stage adenocarcinoma; tumoral tissue revealed differences in expression of 2 proteins compared with normal parenchymal tissue. Of those; difference in protein expression in heat shock protein 60 (HSP60) was found statistically significant (P = 0.0001). Subgroups of early and advanced stage squamos cell carcinoma have differed in certain 20 protein expression of normal tissue and diseased squamos cell carcinoma. Of those, increased protein expression level of only annexin-2 protein was found statistically significant (P = 0.002). No significant difference was detected in early and advanced stage protein expressions of the tumoral tissues in the subgroups of adenocarcinoma and squamous cell carcinoma.

CONCLUSIONS

We conclude that with respect to early diagnosis of lung cancer that HSP60 and annexin-2 proteins are the important biomarkers in the subgroups of adenocarcinoma and squamous cell carcinoma. We also consider that these 2 proteins are molecules which may provide critical contribution in evaluation of prognosis, metastatic potential, response to treatment, and in establishment of differential diagnosis between adenocarcinoma and squamous cell carcinoma.

Doxorubicin anti-tumor mechanisms include Hsp60 post-translational modifications leading to the Hsp60/p53 complex dissociation and instauration of replicative senescence

The chaperone Hsp60 is pro-carcinogenic in certain tumor types by interfering with apoptosis and with tumor cell death. In these tumors, it is not yet known whether doxorubicin anti-tumor effects include a blockage of the pro-carcinogenic action of Hsp60. We found a doxorubicin dose-dependent viability reduction in a human lung mucoepidermoid cell line that was paralleled by the appearance of cell senescence markers. Concomitantly, intracellular Hsp60 levels decreased while its acetylation levels increased. The data suggest that Hsp60 acetylation interferes with the formation of the Hsp60/p53 complex and/or promote its dissociation, both causing an increase in the levels of free p53, which can then activate the p53-dependent pathway toward cell senescence. On the other hand, acetylated Hsp60 is ubiquitinated and degraded and, thus, the anti-apoptotic effect of the chaperonin is abolished with subsequent tumor cell death. Our findings could help in the elucidation of the molecular mechanisms by which doxorubicin counteracts carcinogenesis and, consequently, it would open new roads for the development of cancer treatment protocols targeting Hsp60.

Hsp60 chaperonopathies and chaperonotherapy: targets and agents

INTRODUCTION

Hsp60 (Cpn60) assembles into a tetradecamer that interacts with the co-chaperonin Hsp10 (Cpn10) to assist client polypeptides to fold, but it also has other roles, including participation in pathogenic mechanisms.

AREA COVERED

Hsp60 chaperonopathies are pathological conditions, inherited or acquired, in which the chaperone plays a determinant etiologic-pathogenic role. These diseases justify selection of Hsp60 as a target for developing agents that interfere with its pathogenic effects. We provide information on how to proceed.

EXPERT OPINION

The information available encourages the development of ways to improve Hsp60 activity (positive chaperonotherapy) when deficient or to block it (negative chaperonotherapy) when pathogenic. Many questions are still unanswered and obstacles are obvious. More information is needed to establish when and why autologous Hsp60 becomes a pathogenic autoantigen, or induces cytokine formation and inflammation, or favors carcinogenesis. Clarification of these points will take considerable time. However, analysis of the Hsp60 molecule and a search for active compounds aimed at structural sites that will affect its functioning should continue without interruption. No doubt that some of these compounds will offer therapeutic hopes and will also be instrumental for dissecting structure-function relationships at the biochemical and biological (using animal models and cultured cells) levels.

HSP60 predicts survival in advanced serous ovarian cancer

OBJECTIVE

Heat shock protein 60 (HSP60) plays an essential role in malignant cell survival. We evaluated the prognostic and treatment predictive value of HSP60 in advanced ovarian cancer.

METHODS

Fresh tumor samples were prospectively collected from 123 patients undergoing primary surgery for suspected advanced ovarian cancer. Of these, 57 fulfilled the eligibility criteria, that is, International Federation of Gynecology and Obstetrics stage IIC-IV, serous/endometrioid tumors, platinum-based chemotherapy, and specimens with 50% tumor cells or greater. Heat shock protein 60 mRNA and protein expression was determined by real-time polymerase chain reaction and immunohistochemistry. We estimated the association between HSP60 and overall survival (OS) and platinum-free interval (PFI) by Cox proportional hazards models and its relationship with treatment response by Fisher's exact test. Median follow-up was 60 months.

RESULTS

High HSP60 mRNA expression was associated with shorter OS (hazard ratio [HR], 3.4; 95% confidence interval [CI], 1.3-8.5) and PFI (HR, 3.3; 95% CI, 1.5-7.2). Likewise, high HSP60 protein expression was associated with shorter OS (HR, 3.2; 95% CI, 1.5-7.1) and PFI (HR, 2.6; 95% CI, 1.3-5.3). Median survival for patients with high HSP60 protein expression was 31 months compared with 55 months for low expression cases (P = 0.016). The impact on OS and PFI was even stronger in the subgroup of grade 3 serous tumors. All patients with low HSP60 levels responded to first-line chemotherapy.

CONCLUSION

Heat shock protein 60 may identify groups of advanced serous ovarian cancer with different prognosis and treatment response.

Comparison of the expression of 5 heat shock proteins in benign and malignant salivary gland tumor tissues

The objective of this study was to analyze the significance and potential value of heat shock proteins (HSPs) in salivary gland tumors. We found that expression of HSP60, HSP70, HSP86 and HSP84 were all upregulated in both salivary gland benign tumors and malignant tumors, and that the expression of HSP70, HSP86 and HSP84 was more greatly overexpressed in the malignant tumors (each P<0.01). For HSP27, expression was upregulated both in malignant and benign tumors, with less expression observed in malignant tumors (P<0.01). In malignant tumors, expression of HSP27 was negatively correlated with the age of the patients, size of the tumor tissue, occurrence of neural invasion and metastasis (each P<0.05). Additionally, in malignant tumors, HSP70 and HSP86 were both positively correlated with occurrence site, neural invasion and metastasis (each P<0.05), while HSP60 was only negatively correlated with the age of the patients (P<0.05). HSP86 was also positively correlated with malignant degree (P<0.01). In malignant tumors, the proliferation index (PI), which was marked by proliferating cell nuclear antigen (PCNA; PCNA-PI) was 49.95±14.569, which was significantly higher compared with that in benign tumors (P<0.001), which was in accordance with the upregulation of HSP70, HSP86 or HSP84; however, an adverse correlation was found between HSP27 expression and PCNA (each P<0.05). In conclusion, these results suggest that HSPs are involved in the occurrence and development of salivary gland tumors. HSP70, HSP86 and HSP84 retained the higher multiplication capability of the malignant tumor cells, however, HSP27 did not. Thus, the upregulation of HSP70, HSP86 and HSP84 and the downregulation of HSP27 may all be used as biomarkers of the occurrence and development of malignant salivary gland tumors. Moreover, the extremely high expression of HSP86 and HSP84 in benign tumors indicates the malignant transformation potential.

Heat shock proteins and heat shock factor 1 in carcinogenesis and tumor development: an update

Heat shock proteins (HSP) are a subset of the molecular chaperones, best known for their rapid and abundant induction by stress. HSP genes are activated at the transcriptional level by heat shock transcription factor 1 (HSF1). During the progression of many types of cancer, this heat shock transcriptional regulon becomes co-opted by mechanisms that are currently unclear, although evidently triggered in the emerging tumor cell. Concerted activation of HSF1 and the accumulation of HSPs then participate in many of the traits that permit the malignant phenotype. Thus, cancers of many histologies exhibit activated HSF1 and increased HSP levels that may help to deter tumor suppression and evade therapy in the clinic. We review here the extensive work that has been carried out and is still in progress aimed at (1) understanding the oncogenic mechanisms by which HSP genes are switched on, (2) determining the roles of HSF1/HSP in malignant transformation and (3) discovering approaches to therapy based on disrupting the influence of the HSF1-controlled transcriptome in cancer.