calpastatin and Ovarian-Neoplasms

Expression of members of the calpain system are associated with clinical outcome of patients with, amongst others, breast and ovarian cancers, with calpain-2 expression in ovarian cancer being implicated in chemo-resistance and survival. This study aimed, using a large patient cohort and in vitro models, to verify its importance and further investigate the role in ovarian cancer chemoresponse.. Calpain-1, calpain-2, calpain-4 and calpastatin expression were evaluated in primary ovarian carcinomas (n = 575) by immunohistochemistry. Protein expression was assessed, via western blotting, in five ovarian cancer cell lines with various sensitivities towards cisplatin/carboplatin. In vitro calpain activity was inhibited by calpeptin treatment to assess changes in platinum sensitivity by proliferation assay, with expression of genes associated with epithelial-mesenchymal transition being examined by RT. The current study confirmed previous data that high calpain-2 expression is associated with poor overall survival (P = 0.026) and that calpain-1 was not associated with overall survival or progression-free survival. Low expression of calpastatin (P = 0.010) and calpain-4 (P = 0.003) were also associated with adverse survival. Such prognostic associations do not seem to be linked with altered tumour sensitivity towards platinum-based chemotherapy. Interestingly, low calpain-1 expression was more frequent in patients with confined tumours (stage 1) (χ. The conventional calpains and calpastatin have been confirmed to play an important role in ovarian cancer; however, the precise mechanisms whereby they exert effects remain to be elucidated.

Topics: Adenocarcinoma, Clear Cell; Adenocarcinoma, Mucinous; Antineoplastic Combined Chemotherapy Protocols; Biomarkers, Tumor; Calcium-Binding Proteins; Calpain; Cell Proliferation; Cohort Studies; Cystadenocarcinoma, Serous; Endometrial Neoplasms; Epithelial-Mesenchymal Transition; Female; Follow-Up Studies; Gene Expression Regulation, Neoplastic; Humans; Middle Aged; Ovarian Neoplasms; Prognosis; Survival Rate; Tumor Cells, Cultured

Ovarian cancer is routinely treated with surgery and platinum-based chemotherapy. Resistance is a major obstacle in the efficacy of this chemotherapy regimen and the ability to identify those patients at risk of developing resistance is of considerable clinical importance. The expression of calpain-1, calpain-2 and calpastatin were determined using standard immunohistochemistry on a tissue microarray of 154 primary ovarian carcinomas from patients subsequently treated with platinum-based adjuvant chemotherapy. High levels of calpain-2 expression was significantly associated with platinum resistant tumours (P = 0.031). Furthermore, high expression of calpain-2 was significantly associated with progression-free (P = 0.049) and overall survival (P = 0.006) in this cohort. The association between calpain-2 expression and overall survival remained significant in multivariate analysis accounting for tumour grade, stage, optimal debulking and platinum sensitivity (hazard ratio = 2.174; 95% confidence interval = 1.144-4.130; P = 0.018). The results suggest that determining calpain-2 expression in ovarian carcinomas may allow prognostic stratification of patients treated with surgery and platinum-based chemotherapy. The findings of this study warrant validation in a larger clinical cohort.

Topics: Adult; Aged; Aged, 80 and over; Calcium-Binding Proteins; Calpain; Chemotherapy, Adjuvant; Disease Progression; Female; Follow-Up Studies; Gene Expression Regulation; Humans; Immunohistochemistry; Middle Aged; Multivariate Analysis; Ovarian Neoplasms; Platinum Compounds; Prognosis; Proportional Hazards Models; Retrospective Studies

Calpains, also called calcium activated neutral proteases (CANP), are expressed ubiquitously. They are intracellular, non-lysosomal cytoplasmic cysteine endopeptidases. Calcium is required for their activation. Their endogenous specific inhibitor is calpastatin, which is expressed ubiquitously and coexists within cells besides calpain. When calcium is present, calpastatin and calpain attach to each other inhibiting the protease. The calpain system plays an important role in many processes including apoptosis, necrosis, ischemia formation and exocytosis. So far, many reports exist on studies about the influence of calpains in different tumors (skin, breast, renal cell and prostate cancers). The role of calpains in pathogenesis or further tumor progression has always been proved in related studies, but their exact function could not be demonstrated. So far, no studies on calpains being involved in the pathogenesis of ovarian cancer have been published. In our study we focused on the expression of the enzymes calpain 1, calpain 2 and their inhibitor calpastatin in normal and malign ovarian tissue. Therefore, we performed immunohistochemical stainings of paraffin slices and evaluated staining intensity (SI), percentage of positive cells (PP) and immunoreactive score (IRS). We evaluated the correlation between enzyme expression in malign and benign ovarian tissues. In malignant ovarian tissue, we found decreased expression, staining intensity and immunoreactive score of calpastatin. With higher grading of the ovarian carcinoma, staining intensity and immunoreactive score of calpain 1 decreased. Staining intensity of calpain 2 in ovarian carcinoma decreased with increasing lymph node status. We clearly demonstrated differences between enzyme expressions in malign and benign tissue. This study could not find any specific function of calpains. Only few studies in the literature have been found that deal with calpain evaluation of ovarian cancer. Additional studies including more patients are required to elucidate the functional role and impact of calpain in tumors in detail.

Topics: Calcium-Binding Proteins; Calpain; Female; Humans; Immunohistochemistry; Ovarian Neoplasms