OBJECTIVETo investigate the effect of small interfering RNA on cell proliferation and apoptosis in gastric cancer cell lines with high expression of RegIα.

METHODSTotal RNA was isolated from six gastric cancer cell lines,and the expression of RegI α mRNA was detected by RT-PCR. RegI α RNAi expression vector was constructed and stably transfected into MKN45 and AGS cells with high RegI α expression, empty-vector was used as control. RegI α mRNA and protein expression was measured by RT-PCR and Western blot respectively in stable transfected cell lines. Cell proliferation and apoptosis were detected with MTT assay and flow cytometry.

RESULTRT-PCR results indicated that RegI α mRNA expression was significantly inhibited by RNAi in both cell lines compared with empty-vector. Western blot results showed that RegIα protein was down-regulated to (44 ± 4)% and (25 ± 4)% respectively in MKN45 and AGS cells compared to empty-vector. MTT results showed that cell growth was significantly inhibited in MKN45 and AGS cells. The apoptosis rate in MKN45 and AGS cells was remarkable increased compared to that of empty-vector (12.96 ± 0.50)% compared with (3.99 ± 0.30)% and (11.59 ± 1.10)% compared with (4.22 ± 0.40)% (P < 0.05).

CONCLUSIONSmall interfering RNA of RegI α gene can efficiently down-regulate RegI α expression in MKN45 and AGS cell lines, and further inhibit cell growth and induce cell apoptosis.