Abstract:

Objective    To observe the effect of bcl-2 gene-specific RNA interference combined with γ irradiation on apoptosis and radiosensitivity of the gastric carcinoma cell line SGC7901. Methods    The recombinant eukaryotic expression vector pGPH1/GFP/Neo designed to target the bcl-2 gene was transfected into SGC7901 cells by lipofectamin. Stable positive clones were selected with G418. After γ irradiation, the cells were divided into 4 groups: SGC-7901（group A）,irradiation/SGC-7901（group B）,Bcl-2shRNA/SGC-7901（group C） and irradiation/Bcl2shRNA/SGC-7901（group D）.Cell proliferation was detected by CCK-8.Cell apoptosis was observed by AO/PE. The apoptosis rate was determined by flow cytometry. Expression of bcl-2 was determined by Western blot, and compared between transfection cells and non-transfection cells. Results    Western blot analysis indicated that expression of bcl-2 was suppressed by  shRNA and irradiation,   and they had a synergetic effect. The growth of cells in group D was obviously slower than that in the other groups(P＜0.05). Cell inhibitory rates in groups B, C and D were (27.00±5.27)%，(30.10±6.49)% and (98.40±11.35)%, respectively. Apoptosis rates in groups A, B, C and D were（3.80±0.22)%,（20.80±4.15)%，（23.20±4.15）% and （92.90±25.90）%, respectively（P＜0.05）. Conclusions   Bcl-2 gene suppression by RNAi and irradiation can induce cell apoptosis, co-inhibit expression of bcl-2, and obviously increase  radiosensitivity in the human gastric cell line.

Key words: Gastric carcinoma cells; B cell lymphoma/lewkmia2; RNA interference; Apoptosis; Irradiation