The mechanism research of miRNA-21-5p in the targeted regulation of the sensitivity of gastric cancer cells to cisplatin by pdcd4

Objective:To investigate the mechanism of microRNA-21-5p(miRNA-21-5p) in the targeted regulation of sensitivity of gastric cancer resistant cell line SGC7901/DDP to cisplatin by down-regulating the expression of pdcd4 gene.Methods:The inhibition effects of different concentrations of cisplatin(0,1,2,4,8,16,32 μmol/L) on the proliferation of gastric cancer cell line SGC7901 and gastric cancer drug-resistant cell line SGC7901/DDP were detected using the MTT.The relative expression of miRNA-21-5 in SGC7901/DDP cells after transient transfecting of miRNA-21-5p inhibitors was detected using real-time fluorescence quantitative polymerase chain reaction(qRT-PCR).The expressions of pdcd4 protein and mRNA in transfection group,irrelevant sequence transfection group(NC group) and blank transfection group(CON group) were detected after transfecting with miRNA-21-5p inhibitors and irrelevant sequence,respectively.Results:The results of MTT assay showed that the drug-resistant cells SGC7901/DDP were insensitive to cisplatin compared with the parent cells SGC7901(P<0.05).The results of qRT-PCR showed that the expression level of miRNA-21-5p in transfection group was significantly lower than that in NC group and CON group(P<0.01),the expression level of pdcd4 mRNA in transfection group was significantly higher than that in NC group and CON group(P<0.01).The results of Western blot showed that the expression level of pdcd4 protein in transfection group was significantly higher than that in NC group and CON group(P<0.01).Conclusions:The increasing of miRNA-21-5p expression level is beneficial to the proliferation of gastric cancer cells,and can reduce the sensitivity of gastric cancer cells to cisplatin by down-regulating the expression of pdcd4.