OBJECTIVETo observe the effects of miR-224 antisense oligonucleotide (ASO) on the proliferation and apoptosis of gastric cancer cells in vitro and vivo.

METHODSThe expression of miR-224 in the cancer tissues and their adjacent tissues in 120 gastric cancer patients were detected by real-time quantitative PCR. The biological effects of miR-224 ASO on human gastric cancer SGC7901 cells was assessed by MTT assay, clone formation assay, flow cytometry and in vivo experiment in nude mice.

RESULTSCompared with the control group (0.50 ± 0.07), miR-224 ASO significantly reduced the miR-224 mRNA expression in the cancer patients (0.09 ± 0.01, P < 0.05). MTT assay results showed that the survival rate of gastric cells at 24 h, 48 h and 72 h was 53.6%, 59.1% and 70.1% in the miR-224 ASO group, and 12.3%, 17.4% and 24.7%, respectively, in the control group (P < 0.05 for all). Clone formation assay revealed that clone formation rate in the miR-224 ASO group was (5.33 ± 0.74)%, significantly lower than the (33.33 ± 8.38)% in the control group (P < 0.05). Flow cytometry indicated that the apoptotic index was (15.68 ± 1.46)% in the miR-224 ASO group and (3.36 ± 0.88)% in the control group (P < 0.01). In addition, the expressions of Bcl2 mRNA and protein were 1.05 ± 0.04 and 0.21 ± 0.03 in the miR-224 ASO group, significantly lower than that in the control group (4.87 ± 0.96 and 0.88 ± 0.09, P < 0.01). The in vivo study further showed that the tumor volume in the experimental group is significantly smaller than that in the control group (P = 0.01).

CONCLUSIONSMiR-224 is overexpressed in human gastric cancer. Reducing the expression of miR-224 can effectively inhibit the growth and promote apoptosis of gastric cancer cells. miR-224 may become a new target for the regulation of gene expression in gastric cancer.