miR-485-3p regulates radiosensitivity of gastric cancer cells by targeting ATR

Objective To investigate the effect of miR-485-3p on the radiosensitivity of gastric carcinoma MGC803 cells and the possible mechanism of action. Methods The MGC803 cells were transfected with miR-485-3p mimic or ATR siRNA and then treated by radiation. The MTT method, colony-forming assay, and apoptosis test were used to measure the change in radiosensitivity of such cells. RT-PCR and Western blot were used to measure the changes in the expression of miR-485-3p and ATR, and DIANA, TargetScan, and miRanda software and dual-luciferase reporter assay were used to verify the targeted effect of miR-485-3p on ATR. Results After radiation treatment, the expression of miR-485-3p in gastric carcinoma cells was downregulated. The overexpression of miR-485-3p reduced the proliferative capacity and colony-forming ability of cells, increased apoptosis rate, and thus increased radiosensitivity. The software for target gene prediction found that ATR might be the target gene of miR-485-3p, and the dual-luciferase reporter assay further confirmed that ATR was the direct target of miR-485-3p. The miR-485-3p downregulated the expression of ATR, and the inhibition of the ATR signaling pathway by transfection with ATR siRNA increased the radiosensitivity of gastric carcinoma cells. Conclusions The miR-485-3p may target at ATR and regulate the radiosensitivity of gastric carcinoma cells through inhibiting the ATR signaling pathway. Key words: miR-485-3p; ATR pathway; Cell line, neopasms; Radiosensitivity