MiR-135b improves proliferation and regulates chemotherapy resistance in ovarian cancer.

MicroRNAs act as regulators in ovarian tumorigenesis and progression by involving different molecular pathways. Here, we examined the role of miR-135b on growth, chemotherapy resistance in OVCAR3 and SKOV3 ovarian cancer cells. MTT assay was performed to examine proliferation. Transwell migration and matrigel invasion assays were used to assess migration and invasion. Caspase-Glo3/7 assay was carried out to evaluate apoptosis. The dual-luciferase reporter assay was performed to validate the putative binding site. Meanwhile, the miR-135b levels in human ovarian cancer tissue were detected by qPCR assay. Overexpression of miR-135b increased growth, and improved migration and invasion in ovarian cancer cells. Meanwhile, overexpression of miR-135b decreased the cisplatin treatment sensitivity in OVCAR3 and SKOV3 cells. The cisplatin-induced apoptosis was decreased by miR-135b. Furthermore, miR-135b could alter epithelial to mesenchymal transition (EMT) associated proteins expression including E-cadherin, N-cadherin, snail and Vimentin in ovarian cancer cells. Further study demonstrated aberrant expression of miR-135b regulated PTEN and p-AKT expression in ovarian cancer cells. The expression level of miR-135b was increased in human ovarian cancer tissue, compared with normal ovary tissue. MiR-135b involves in tumorigenesis and progression in ovarian cancer cells, and might serve as a promising biomarker to predict chemotherapy sensitivity and prognosis in ovarian cancer.