MiR-129 reduces CDDP resistance in gastric cancer cells by inhibiting MAPK3.

Abstract

Abnormal expression of mitogen-activated protein kinase 3 (MAPK3) is related to invasion, metastasis, and drug resistance of multiple tumor cells. MiR-129 expression is associated with gastric cancer. Bioinformatics analysis showed a targeting relation between miR-129 and MAPK3. This study investigated whether miR-129 plays a role in regulating MAPK3 expression, affecting proliferation, apoptosis, and cisplatin (CDDP) resistance of gastric cancer cells. The dual-luciferase reporter gene assay was used to assess the targeted regulation between miR-129 and MAPK3. The expression of miR-129 and MAPK3 in CDDP-resistant cell line MGC-803/CDDP and the parental MGC-803 cells was measured. MGC-803/CDDP cells were cultured in vitro and divided into miR-NC group and miR-129 mimic group. The expression of MAPK3 and p-MAPK3 protein were detected by Western blot and the effect of CDDP treatment on cell apoptosis and proliferation was detected by flow cytometry. There was a targeted regulation relation between miR-129 and MAPK3 mRNA. MiR-129 expression in MGC-803/CDDP cells was significantly lower than that in MGC-803 cells and the expression of MAPK3 mRNA and protein was significantly higher than that in MGC-803 cells. Compared with miR-NC group, the expression of MAPK3 and p-MAPK3 in MHC-803/CDDP cells in miR-129 mimic transfection group was significantly decreased, with increased cell apoptosis and reduced cell proliferation. The decreased expression of miR-129 and the up-regulation of MAPK3 are associated with CDDP resistance in gastric cancer cells. Overexpression of miR-129 inhibits MAPK3 expression and cell proliferation, it induces cell apoptosis and reduces CDDP resistance.