Inhibitory effect of nigericin on human epithelial ovarian cancer cells and its mechanism

Abstract

Objective To ascertain the specific activities of nigericin on inhibiting human epithelial ovarian cancer (EOC) cells, and to investigate the possible molecular mechanism of nigericin on cell migration and invasion. Methods Cell viability under different treatments of nigericin (0.312 5, 0.625, 1.25, 2.5, 5, 10, 20, 40, 80 μmol/L) on EOC A2780 and SKOV3 cell lines was examined by CCK-8 assay, with DMSO as a control. The human epithelial ovarian cancer cell lines A2780 and SKOV3 were treated with 5, 10 or 20 μmol/L nigericin or with DMSO as a control. Transwell chambers was used to observe the impact of nigericin on migration and invasion of EOC cells. Western blot was used to detect the expressions of epithelial cell marker (E-cadherin), mesenchymal cell marker (Vimentin) and the epithelial-mesenchymal transition (EMT)-related transcription factors Slug, Snail, and Twist, as well as the expressions of proteins related to Wnt/β-catenin signaling pathway such as Gsk-3β, p-Gsk-3β and β-catenin under different concentration treatment of nigericin. Results CCK-8 assay showed that nigericin exhibited strong cytotoxicity on A2780 [IC50 (16.19±0.26) μmol/L, 95% CI 1.077-1.341)] and SKOV3 [IC50 (11.87±0.21) μmol/L, 95% CI 1.003-1.146] cell lines. Transwell chamber assay revealed that nigericin at different concentration (5, 10, 20 μmol/L) induced a remarkable reduction in the number of cells migrating through the membrane relative to the vehicle-treated controls in A2780 and SKOV3 cells [(121±9), (92±7), (59±5)/HP and (120.4±2.6), (91.8±5.5), (80.0±4.0)/HP, all P < 0.05]; the invasive ability of A2780 and SKOV3 cells also inhibited [(61.2±3.7), (43.2±4.3), (23.6±2.1)/HP and (85.2±7.0), (65.2±4.6), (45.6±4.4)/HP, all P < 0.05]. Western blot revealed that the increased expression of E-cadherin and decreased expression of Vimentin, Slug, Snail, Twist, p-Gsk-3β, β-catenin in EOC cells with the nigericin treatment at different concentration (5, 10 and 20 μmol/L) showed concentration dependence (P < 0.05). Conclusion Nigericin may induce EMT by activating Wnt-β-catenin signaling pathway to promote the migration and invasion of EOC cells. Key words: Ovarian neoplasms; Nigericin; Epithelial-mesenchymal transition; Migration; Invasion