Correlation of OPN gene expression with proliferation and apoptosis of ovarian cancer cells and prognosis of patients

Correlation of osteopontin (OPN) gene expression with proliferation and apoptosis of ovarian cancer cells and prognosis of patients was investigated. The expression levels of OPN in 81 pairs of ovarian cancer tissues and para-carcinoma tissues obtained via surgical resection were detected using immunohistochemistry (IHC). The correlation of OPN protein expression with clinicopathological features of patients was analyzed. All patients were followed up for 3 years. The disease-free survival (DFS) and overall survival (OS) curves of patients in high/low OPN expression groups were drawn using the Kaplan-Meier method. The expression levels of OPN in normal ovarian epithelial IOSE80 cells and 5 ovarian cancer cell lines were detected via western blotting. Moreover, two cell lines with high OPN expression were interfered with lentiviral transfection technique. The effects of OPN on ovarian cancer cell proliferation and apoptosis were detected and analyzed via Cell Counting Kit-8 (CCK8) assay and flow cytometry. The positive expression rate of OPN protein in tumor tissues was higher than that in para-carcinoma tissues (P<0.05). Survival curves suggested that both DFS and OS in OPN negative group were superior to those in OPN positive group (P<0.05). Results of western blotting showed that OPN was weakly expressed in IOSE80 cells, whereas it was highly expressed in SKOV-3, COC1, A2780, HO-8910 and OVCAR-3 cells, among which the OPN protein expression levels were relatively higher in SKOV-3 and OVCAR-3 cell lines. After knockdown of OPN gene with sh-OPN, the cell proliferation rates of OVCAR-3 and SKOV-3 were significantly decreased from 48 h (P<0.05), but the apoptosis level was increased remarkably (28.2 vs. 1.3% and 25.3 vs. 3.2%), and differences were statistically significant (P<0.05). In conclusion, overexpression of OPN enhances the proliferation of ovarian cancer cells, which is an adverse factor for patient survival and prognosis.