3309

HSPA5

heat shock 70kDa protein 5 (glucose-regulated protein, 78kDa);HSPA5;heat shock 70kDa protein 5 (glucose-regulated protein, 78kDa)

78 kDa glucose-regulated protein|endoplasmic reticulum lumenal Ca(2+)-binding protein grp78|epididymis secretory sperm binding protein Li 89n|immunoglobulin heavy chain-binding protein

9q33.3

protein-coding

Glucose-related proteins (GRPs) are ubiquitously expressed in endoplasmic reticulum and able to assist in protein folding and assembly; consequently, they are considered as molecular chaperones. GRP78 and GRP94 expression was induced by glucose starvation and up-regulated in the malignancies. To clarify the roles of both molecules in tumorigenesis and progression of gastric carcinomas, immunohistochemistry was used on tissue microarray containing gastric carcinomas, adenomas, and nonneoplastic mucosa using the antibodies against GRP78 and GRP94, with a comparison of their expression with clinicopathological parameters of carcinomas. Gastric carcinoma cell lines (MKN28, AGS, MKN45, KATO-III, and HGC-27) were studied for both proteins by immunohistochemistry and Western blot. There was more expression of both proteins in gastric carcinoma and adenoma than in nonneoplastic mucosas (P < .05). All gastric carcinoma cell lines showed their expression at different levels. They were positively correlated with tumor size, depth of invasion, lymphatic and venous invasion, lymph node metastasis, and Union Internationale Contre le cancer staging (P < .05), with positive relationship between both proteins (P < .05). Univariate analysis indicated the postsurgical cumulative survival rate of patients with positive GRP78 or GRP94 expression to be lower than that in those without GRP78 or GRP94 expression (P < .05), but the close link disappeared if stratified according to depth of invasion (P > .05). Multivariate analysis showed that age, depth of invasion, lymphatic invasion, lymph node metastasis, Union Internationale Contre le cancer staging, and Lauren classification (P < .05), but not GRP78 and GRP94 expression, were independent prognostic factors for carcinomas (P > .05). Up-regulated expression of GRP78 and GRP94 was possibly involved in pathogenesis, growth, invasion, and metastasis of gastric carcinomas. They were considered objective and effective markers for the aggressive behavior and poor prognosis in gastric carcinomas.

BACKGROUND: Survivin has multiple functions during the progression of cancer. However, the role of survivin in the progression and metastasis of hepatocellular carcinoma (HCC) remains unknown. MATERIALS AND METHODS: Survivin expression in HCC cells (Mahlavu and Hep3B) was assessed using reverse transcription real-time PCR and Western blot analyses. In addition, survivin expression in HCC cells was manipulated using small interfering RNA (siRNA) or overexpression and proliferation and transwell migration assays were performed to monitor the effect of manipulated survivin expression on the growth rate and migratory ability of the transfected cells. RESULTS: Among the HCC cell lines tested, we found high endogenous expression of survivin mRNA and protein in Mahlavu cells. After silencing survivin expression in Mahlavu cells, there was a dramatic decrease in the cell growth rate and an increase in the metastatic potential of the cells. Overexpression of survivin in Hep3B cells suppressed the ability of the cell to migrate. The mechanism of enhanced cell migration caused by decreased survivin expression is mediated through the downregulation of glucose-regulated protein 78 (GRP78) and the upregulation of the epithelial-mesenchymal transition (EMT) marker, vimentin. CONCLUSIONS: Survivin may mediate metastasis in HCC. The knockdown of survivin expression may enhance cancer metastasis through the downregulation of GRP78 and upregulation of vimentin expression.

BACKGROUND: Survivin has multiple functions during the progression of cancer. However, the role of survivin in the progression and metastasis of hepatocellular carcinoma (HCC) remains unknown. MATERIALS AND METHODS: Survivin expression in HCC cells (Mahlavu and Hep3B) was assessed using reverse transcription real-time PCR and Western blot analyses. In addition, survivin expression in HCC cells was manipulated using small interfering RNA (siRNA) or overexpression and proliferation and transwell migration assays were performed to monitor the effect of manipulated survivin expression on the growth rate and migratory ability of the transfected cells. RESULTS: Among the HCC cell lines tested, we found high endogenous expression of survivin mRNA and protein in Mahlavu cells. After silencing survivin expression in Mahlavu cells, there was a dramatic decrease in the cell growth rate and an increase in the metastatic potential of the cells. Overexpression of survivin in Hep3B cells suppressed the ability of the cell to migrate. The mechanism of enhanced cell migration caused by decreased survivin expression is mediated through the downregulation of glucose-regulated protein 78 (GRP78) and the upregulation of the epithelial-mesenchymal transition (EMT) marker, vimentin. CONCLUSIONS: Survivin may mediate metastasis in HCC. The knockdown of survivin expression may enhance cancer metastasis through the downregulation of GRP78 and upregulation of vimentin expression.

PURPOSE: The ER chaperone GRP78 translocates to the surface of tumor cells and promotes survival, metastasis, and resistance to therapy. An oncogenic function of cell surface GRP78 has been attributed to the activation of the phosphoinositide 3-kinase (PI3K) pathway. We intend to use a novel anti-GRP78 monoclonal antibody (MAb159) to attenuate PI3K signaling and inhibit tumor growth and metastasis. EXPERIMENTAL DESIGN: MAb159 was characterized biochemically. Antitumor activity was tested in cancer cell culture, tumor xenograft models, tumor metastasis models, and spontaneous tumor models. cancer cells and tumor tissues were analyzed for PI3K activity. MAb159 was humanized and validated for diagnostic and therapeutic application. RESULTS: MAb159 specifically recognized surface GRP78, triggered GRP78 endocytosis, and localized to tumors but not to normal organs in vivo. MAb159 inhibited tumor cell proliferation and enhanced tumor cell death both in vitro and in vivo. In MAb159-treated tumors, PI3K signaling was inhibited without compensatory MAPK pathway activation. Furthermore, MAb159 halted or reversed tumor progression in the spontaneous PTEN-loss-driven prostate and leukemia tumor models, and inhibited tumor growth and metastasis in xenograft models. Humanized MAb159, which retains high affinity, tumor specific localization, and the antitumor activity, was nontoxic in mice, and had desirable pharmacokinetics. CONCLUSIONS: GRP78-specific antibody MAb159 modulates the PI3K pathway and inhibits tumor growth and metastasis. Humanized MAb159 will enter human trials shortly.

The purpose of this study was to detect the expressions of GRP78 and Bax in human non-small cell lung cancer (NSCLC) tissues, to analyze their correlations with carcinogenesis and the development of NSCLC, and to investigate the relationship of GRP78 expression to metastasis and apoptosis in the NSCLC cell line HCC827. The positive expression rates of GRP78 and Bax in NSCLC lung tissues were 59.7% and 34.7% by RT-PCR, respectively. The mRNA and protein expression levels of GRP78 in NSCLC tissues were significantly higher than that in the relatively normal surrounding lung tissues (p < 0.05); the lesser the degree of tumor differentiation was, the higher the mRNA and protein expression levels of GRP78 were (p < 0.05). The mRNA and protein expression levels of GRP78 from patients in advanced pathological stages (III-IV) were significantly higher than the corresponding levels in patients in early pathological stages (I-II) (p < 0.05); the mRNA and protein expression levels of GRP78 in patients with positive lymph node metastasis were significantly higher than those in patients with negative lymph node metastasis (p < 0.05). The mRNA and protein expression levels of Bax in the above cases showed the opposite trend of the mRNA and protein expression levels of GRP78. However, the mRNA and protein expression levels of both GRP78 and Bax were independent of the patient's sex, the patient's age, the tumor size and the histological type (adenocarcinoma or squamous cell carcinoma) of NSCLC (p > 0.05). The mRNA expression level of GRP78 and the mRNA expression level of Bax in human NSCLC tissues were negatively correlated (r = -0.353, p = 0.002). After transfection of GRP78 siRNA in HCC827 cells, the GRP78 protein expression level was significantly decreased (p < 0.01), while the Bax protein expression level was significantly increased (p < 0.01); the number of cells that passed through the Transwell chamber was significantly less in the non-transfected control group compared to the transfected control group (p < 0.01). The number of apoptotic cells was significantly greater in the non-transfected control group compared to the transfected control group (p < 0.01). The expression levels of GRP78 and Bax were related to the carcinogenesis, development and metastasis of NSCLC. GRP78 expression with siRNA interference in the human NSCLC cell line HCC827 can reduce metastasis and promote apoptosis in HCC827 cells.

BACKGROUND/PURPOSE: Oral squamous cell carcinoma (OSCC) is an aggressive tumor and its occurrence in Taiwan is closely related to chronic smoking, alcohol consumption, and especially to betel quid chewing. It became the fourth most common malignant tumor of Taiwanese men in 2006. Unfortunately, there are few biomarkers for diagnosis and treatment of this disease. METHODS: To find potential markers, two domestic cell lines (OC2 and OCSL) derived from different grades of OSCC were established and their proteins were compared by global proteomic analysis. The expression differences of GRP78 protein in these two cell lines and clinical samples from OSCC patients were verified. RESULTS: Of the 11 candidate proteins expressed differentially in both cell lines, six [heat shock protein 90 kDa beta member 1 (94 kDa glucose-regulated protein; GRP94), protein disulfide-isomerase precursor, vimentin, tubulin beta-2C chain, 78 kDa glucose-regulated protein precursor (GRP78), and annexin A2] were increased in OC2 cells (low-grade OSCC), and five (heat shock protein 90-beta, annexin A1, stress-induced phosphoprotein 1, elongation factor-2, and integrin alpha-3 precursor) were increased in OCSL cells (high-grade OSCC). Some of these proteins have been previously associated with malignant tumors, but no previous association of GRP78 with OSCC has been reported. GRP78 protein expression in these two OSCC cell lines was confirmed by Western blotting. Immunohistochemical staining of clinical samples from OSCC patients revealed that decreased GRP78 protein expression was significantly correlated with advance tumor stage (p < 0.001) and neck lymph node metastasis (p = 0.001). CONCLUSION: GRP78 protein is a possible biomarker of oral cancer in Taiwan.