MiR-202-5p functionally targets TGFβR2 to regulate GC apoptosis through canonical TGF-β/SMAD signaling. Overexpression of TGFβR2 rescues cell apoptosis in response to miR-202-5p mimics (A). TGFβR2 silencing induces apoptosis in GCs transfected with miR-202-5p inhibitors (B). Cell apoptosis was assessed via FACS ((A,B) left panels) and positive rates were calculated ((A,B) right panels). (C,D) GCs were transfected with the small interfering RNAs (siRNAs) or plasmid vectors and protein levels were analyzed by WB. GCs were cotransfected with miR-202-5p mimics and pcDNA3.1-TGFβR2 (TβR2) or miR-202-5p inhibitor and TGFβR2-siRNA. Relative protein levels ((C,D) middle panels) and p-SMAD3/SMAD3 ((C,D) right panel) expression were calculated. Each experiment was repeated on a minimum of three occasions. Bars indicate the mean ± SEM of three independent replicates; *p < 0.05, **p < 0.01, N.S.: Not significant.