Targeted regulation of miR-195 on MAP2K1 for suppressing ADM drug resistance in prostate cancer cells.

Zhang, J-Y; Li, Y-N; Mu, X; Pan, Z-L; Liu, W-B

OBJECTIVE Extra-cellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) signaling pathway participates in cell proliferation, cycle and apoptosis. MAPK kinase 1 (MAP2K1) activates the ERK/MAPK pathway. The down-regulation of miR-195 is correlated with the onset and drug resistance of prostate cancer. Bioinformatics analysis identified complementary binding sites between miR-195 and MAP2K1. This study aimed to investigate the effect of miR-195 on the proliferation, apoptosis and adriamycin (ADM) resistance of prostate cancer cells. MATERIALS AND METHODS Dual-Luciferase reporter gene assay confirmed targeted regulation between miR-195 and MAP2K1. ADM resistant cell line DU145/ADM and PC-3/ADM were generated for comparing the miR-195 and MAP2K1 expression. Apoptosis was measured by flow cytometry and caspase-3 activity was quantified. Cultured cells were treated with miR-195 mimic, followed by quantitative real-time PCR (qRT-PCR) was used for MAP2K1 expression. Western blot measured MAP2K1, ERK1/2 and phosphorylated ERK1/2 (p-ERK1/2) expression, and flow cytometry quantified cell apoptosis, followed by EdU staining for cell proliferation. RESULTS Targeted regulation existed between miR-195 and MAP2K1 mRNA. Drug-resistant cells had lower miR-195 than parental cells, whilst MAP2K1 expression was higher. Under ADM treatment with IC50 concentration, drug resistant cells showed lower apoptosis. The transfection of miR-195 decreased MAP2K1 expression and p-ERK1/2, elevated cell apoptosis and suppressed EdU positive rate or cell proliferation. CONCLUSIONS The down-regulation of miR-195 is correlated with ADM resistance of prostate cancer cells. The over-expression of miR-195 weakens cancer cell proliferation, facilitates cell apoptosis and decreases ADM resistance via targeted inhibition on MAP2K1 expression and ERK/MAPK signal pathway.