High Expression of Heat Shock Protein 90 Is Associated with Tumor Aggressiveness and Poor Prognosis in Patients with Advanced Gastric Cancer

The heat shock protein 90 (HSP90) is overexpressed and highly associated with poor prognosis in many malignancies. However, the role of HSP90 in gastric cancer has not been thoroughly elucidated. The aim of this study is to investigate the relationship of HSP90 expression with clinicopathological parameters and prognosis in advanced gastric cancer, and estimate the alteration of HSP90 expression after neoadjuvant chemotherapy. HSP90 and matrix metallopeptidase 9 (MMP-9) antigen expression was evaluated by immunohistochemistry in 322 advanced gastric carcinoma samples. The relationships between HSP90 and clinicopathological parameters and prognosis were analyzed. The response of HSP90 level was assessed in chemotherapeutic effect in 54 patients received 1–2 cycles of neoadjuvant chemotherapy. The positive expression of HSP90 was found to be 69.6% in 322 advanced gastric carcinoma samples. HSP90 protein expression was significantly associated with depth invasion (P<0.001), lymph node metastasis (P<0.001) and stage of disease (P<0.001). The positive rates of HSP90 expression were higher in both prominent serosal invasion group (P<0.001) and lymph node metastasis group (P<0.001). Moreover, HSP90 was significantly correlated with MMP-9 among 322 gastric cancer tissues (P<0.001). In univariate and multivariate analyses, HSP90 was an independent prognostic factor for both recurrence-free survival (RFS) and overall survival (OS). These results suggested that HSP90 may play an important role on tumor invasion, metastasis and prognosis, and might act as a promising target for prognostic prediction.     

Heat Shock Protein 60 Overexpression Is Associated with the Progression and Prognosis in Gastric Cancer

Background

Heat shock protein 60 (HSP60) is a chaperonin with essential functions for cell physiology and survival, and its expression correlates with prognosis in a number of malignancies. The aim of this study is to determine the relationship of HSP60 status with clinicopathological parameters and prognosis in gastric cancer.

Methods

The levels of HSP60 and matrix metallopeptidase 9 (MMP-9) antigen was evaluated by immunohistochemistry in 223 gastric carcinoma samples. The association between HSP60 and MMP-9, clinicopathological parameters, and prognosis of gastric cancer was examined.

Results

The level of HSP60 protein was significantly associated with depth invasion, lymph node metastasis and stage of disease (all P<0.05). Both univariate and multivariate analyses revealed that HSP60 was an independent prognostic factor for both overall survival (OS) and recurrence-free survival (RFS) (both P<0.05). Furthermore, HSP60 overexpression was associated with a poor prognosis in patients with advanced gastric cancer in different risk groups. Moreover, HSP60 was significantly correlated with MMP-9 among 223 gastric cancer tissues (P<0.001). Patients who had HSP60 overexpression, in which tumor cells displayed high invasiveness, had poor OS and shorter RFS.

Conclusion

HSP60 plays an important role on tumor aggressiveness and prognosis, and may act as a promising target for prognostic prediction.     

Aberrant Expression and Secretion of Heat Shock Protein 90 in Patients with Bullous Pemphigoid

The cell stress chaperone heat shock protein 90 (Hsp90) has been implicated in inflammatory responses and its inhibition has proven successful in different mouse models of autoimmune diseases, including epidermolysis bullosa acquisita. Here, we investigated expression levels and secretory responses of Hsp90 in patients with bullous pemphigoid (BP), the most common subepidermal autoimmune blistering skin disease. In comparison to healthy controls, the following observations were made: (i) Hsp90 was highly expressed in the skin of BP patients, whereas its serum levels were decreased and inversely associated with IgG autoantibody levels against the NC16A immunodominant region of the BP180 autoantigen, (ii) in contrast, neither aberrant levels of circulating Hsp90 nor any correlation of this protein with serum autoantibodies was found in a control cohort of autoimmune bullous disease patients with pemphigus vulgaris, (iii) Hsp90 was highly expressed in and restrictedly released from peripheral blood mononuclear cells of BP patients, and (iv) Hsp90 was potently induced in and restrictedly secreted from human keratinocyte (HaCaT) cells by BP serum and isolated anti-BP180 NC16A IgG autoantibodies, respectively. Our results reveal an upregulated Hsp90 expression at the site of inflammation and an autoantibody-mediated dysregulation of the intracellular and extracellular distribution of this chaperone in BP patients. These findings suggest that Hsp90 may play a pathophysiological role and represent a novel potential treatment target in BP.     

Cyclic Stretch up-regulates Proliferation and Heat Shock Protein 90 Expression in Human Melanocytes

Human skin is repeatedly exposed to mechanical stretching in vivo, but in an ordinary culture of skin cells this prominent feature has been neglected. In order to study whether mechanical stretching plays a role for human melanocytes, we have established a culture technique to mimic this physical stretching: primary cultures of human melanocytes were plated on silicon supports, which undergo a stretching of about 10% of the initial length. After application of repeated stretching and relaxation for 4 days, cell count was significantly (about 40%) enhanced. In addition, we found ～ 2-fold increase in heat shock protein (HSP) 90, both at the protein and mRNA level. HSP 90 is known to bind to Raf-1 and, therefore, may contribute to the Raf-1-MEK (mitogen-activated protein-kinase kinase)-MAPK (mitogen-activated protein-kinase) signaling pathway. Disruption of the Raf-1-HSP 90 multimolecular complex by geldanamycin lead to a considerable decrease in melanocyte cell count. However, geldanamycin did not reverse the stretch-induced growth stimulation. Therefore, the stretch-mediated up-regulation of HSP 90 expression in melanocytes appears to be independent of stretch-mediated growth stimulation. These findings have strong implications for the in vitro cultivation of melanocytes for transplantation purposes.     

Activity of the Heat Shock Protein 90 Inhibitor Ganetespib in Melanoma

Heat shock protein 90 (HSP90) is involved in the regulation of diverse biological processes such as cell signaling, proliferation and survival, and has been recently recognized as a potential target for cancer therapy. Ganetespib is a potent ATP competitive inhibitor of HSP90. Ganetespib downregulated the expression of multiple signal transducing molecules including EGFR, IGF-1R, c-Met, Akt, B-RAF and C-RAF, resulting in pronounced decrease in phosphorylation of Akt and Erk1/2 in a panel of five cutaneous melanoma cell lines including those harboring B-RAF and N-RAS mutations. Ganetespib exhibited potent antiproliferative activity on all five of these cell lines, with IC50 values between 37.5 and 84 nM. Importantly, Ganetespib is active on B-RAF mutated melanoma cells that have acquired resistance to B-RAF inhibition. Ganetespib induced apoptosis and cell cycle arrest at G1 and/or G2/M phase. Ganetespib induced cell cycle arrest was accompanied by altered expression of cyclin-dependent kinase inhibitor (CDKI) p21^Cip1 and p27^Kip1, cyclins B1, D1 and E, and/or cyclin-dependent kinases 1, 2 and 4. HSP90 is functionally important for melanoma cells and HSP90 inhibitors such as ganetespib could potentially be effective therapeutics for melanoma with various genetic mutations and acquired resistance to B-RAF inhibition.     

植物热激蛋白90的结构和功能

文章从结构和功能两个方面介绍植物热激蛋白90的研究进展。     

The Membrane-Associated Transient Receptor Potential Vanilloid Channel Is the Central Heat Shock Receptor Controlling the Cellular Heat Shock Response in Epithelial Cells

The heat shock response (HSR) is a highly conserved molecular response to various types of stresses, including heat shock, during which heat-shock proteins (Hsps) are produced to prevent and repair damages in labile proteins and membranes. In cells, protein unfolding in the cytoplasm is thought to directly enable the activation of the heat shock factor 1 (HSF-1), however, recent work supports the activation of the HSR via an increase in the fluidity of specific membrane domains, leading to activation of heat-shock genes. Our findings support the existence of a plasma membrane-dependent mechanism of HSF-1 activation in animal cells, which is initiated by a membrane-associated transient receptor potential vanilloid receptor (TRPV). We found in various non-cancerous and cancerous mammalian epithelial cells that the TRPV1 agonists, capsaicin and resiniferatoxin (RTX), upregulated the accumulation of Hsp70, Hsp90 and Hsp27 and Hsp70 and Hsp90 respectively, while the TRPV1 antagonists, capsazepine and AMG-9810, attenuated the accumulation of Hsp70, Hsp90 and Hsp27 and Hsp70, Hsp90, respectively. Capsaicin was also shown to activate HSF-1. These findings suggest that heat-sensing and signaling in mammalian cells is dependent on TRPV channels in the plasma membrane. Thus, TRPV channels may be important drug targets to inhibit or restore the cellular stress response in diseases with defective cellular proteins, such as cancer, inflammation and aging.     

Heat Shock Protein 72 Is Associated with the Hepatitis C Virus Replicase Complex and Enhances Viral RNA Replication

The NS5A protein of the hepatitis C virus (HCV) is an integral component of the viral replicase. It also modulates cellular signaling and perturbs host interferon responses. The multifunctional characteristics of NS5A are mostly attributed to its ability to interact with various cellular proteins. This study aimed to identify the novel cellular factors that interact with NS5A and decipher the significance of this interaction in viral replication. The NS5A-interacting proteins were purified by the tandem affinity purification (TAP) procedure from cells expressing NS5A and identified by mass spectrometry. The chaperone protein Hsp72 was identified herein. In vivo protein-protein interaction was verified by co-immunoprecipitation and an in situ proximity ligation assay. In addition to NS5A, Hsp72 was also associated with other members of the replicase complex, NS3 and NS5B, suggesting that it might be directly involved in the HCV replication complex. Hsp72 plays a positive regulatory role in HCV RNA replication by increasing levels of the replicase complex, which was attributed either to the increased stability of the viral proteins in the replicase complex or to the enhanced translational activity of the internal ribosome entry site of HCV. The fact that the host chaperone protein Hsp72 is involved in HCV RNA replication may represent a therapeutic target for controlling virus production.     

受孔雀石绿胁迫的近江牡蛎HSP90基因的表达变化

HSP90是重要抗逆分子,为了探讨近江牡蛎Crassostrea hongkongensis HSP90分子在抗逆中的作用,本研究建立实时荧光定量PCR方法,研究了在孔雀石绿胁迫下近江牡蛎HSP90基因在外套膜、消化腺、鳃、闭壳肌4种器官组织中的表达变化规律.结果显示,在浓度1μg/L的孔雀石绿处理下,4种器官组织中的...     

Functional Expression and Subcellular Localization of the Aflatoxin Pathway Enzyme Ver-1 Fused to Enhanced Green Fluorescent Protein

Aflatoxin, a mycotoxin synthesized by Aspergillus spp., is among the most potent naturally occurring carcinogens known. Little is known about the subcellular organization of aflatoxin synthesis. Previously, we used transmission electron microscopy and immunogold labeling to demonstrate that the late aflatoxin enzyme OmtA localizes primarily to vacuoles in fungal cells on the substrate surface of colonies. In the present work, we monitored subcellular localization of Ver-1 in real time in living cells. Aspergillus parasiticus strain CS10-N2 was transformed with plasmid constructs that express enhanced green fluorescent protein (EGFP) fused to Ver-1. Analysis of transformants demonstrated that EGFP fused to Ver-1 at either the N or C terminus functionally complemented nonfunctional Ver-1 in recipient cells. Western blot analysis detected predominantly full-length Ver-1 fusion proteins in transformants. Confocal laser scanning microscopy demonstrated that Ver-1 fusion proteins localized in the cytoplasm and in the lumen of up to 80% of the vacuoles in hyphae grown for 48 h on solid media. Control EGFP (no Ver-1) expressed in transformants was observed in only 13% of the vacuoles at this time. These data support a model in which middle and late aflatoxin enzymes are synthesized in the cytoplasm and transported to vacuoles, where they participate in aflatoxin synthesis.     

Targeting Heat Shock Protein 90 for the Treatment of Malignant Pheochromocytoma

Metastatic pheochromocytoma represents one of the major clinical challenges in the field of neuroendocrine oncology. Recent molecular characterization of pheochromocytoma suggests new treatment options with targeted therapies. In this study we investigated the 90 kDa heat shock protein (Hsp90) as a potential therapeutic target for advanced pheochromocytoma. Both the first generation, natural product Hsp90 inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG, tanespimycin), and the second-generation synthetic Hsp90 inhibitor STA-9090 (ganetespib) demonstrated potent inhibition of proliferation and migration of pheochromocytoma cell lines and induced degradation of key Hsp90 clients. Furthermore, ganetespib induced dose-dependent cytotoxicity in primary pheochromocytoma cells. Using metastatic models of pheochromocytoma, we demonstrate the efficacy of 17-AAG and ganetespib in reducing metastatic burden and increasing survival. Levels of Hsp70 in plasma from the xenograft studies served as a proximal biomarker of drug treatment. Our study suggests that targeting Hsp90 may benefit patients with advanced pheochromocytoma.     

Expression of Heat Shock Protein 90 (hsp90) in Neural and Nonneural Tissues of the Control and Hyperthermic Rabbit

Tissue-specific differences were apparent in the constitutive level of hsp90 in various body tissues of the unstressed rabbit. Western blotting with monoclonal antibody 29A revealed very low levels in muscle and highest levels in neural regions (cerebellum, cerebral hemispheres, and retina) and in testes and thymus. Intermediate levels were apparent in other tissues such as liver, kidney, heart, and small intestine. Following hyperthermia, induction of hsp90 was not detected with 1-D Western blotting in tissues which demonstrated high constitutive levels; however, elevations were noted in tissues which showed lower constitutive amounts of the protein, such as kidney, heart, and muscle. Immunocytochemical studies revealed that hsp90 is preferentially localized to neuronal cell populations in the rabbit brain and that this pattern does not alter following hyperthermic conditions which result in glial induction of hsp70. In kidney, where constitutive levels of hsp90 are lower than in brain, an induction of hsp90 was noted in renal tubules following hyperthermia.