Inhibiting Bcl-2 gene expression enhance radiosensitivity of non-small cell lung cancer NCI-H460 cells

Background and purpose:Bcl-2 could inhibit apoptosis,it is frequently exist in a number of tumor types.This study investigated whether small hairpin RNA (shRNA) targeting Bcl-2 could render NCI-H460 cells more susceptible to X-ray radiation induced apoptosis therefore increasing the radiosensitivity of NCI-H460 cells.Methods:Recombinant Bcl-2 shRNA expression vectors were transfected into NCI-H460 cells.These stable cells that were transfected with positive plasmid were then named H460-RNAi cells,with negative plasmid cells were named H460-Neg cells and without transfection cells were named H460.Expression of the Bcl-2 protein was assayed using Western blot in NCI-H460 cells.Radiation-induced apoptosis was determined by morphological observation and radiosensitivity was measured by clonogenic assay after radiation.Results:Expression levels of Bcl-2 protein from H460-RNAi cells significantly decreased compared with the other two groups (P0.05).The apoptotic rate of H460-RNAi cells [(10.8±0.7)%] was significantly higher than H460-Neg cells and H460 cells (P0.05).After treatment with radiation at 48 h,H460-RNAi cells displayed a signifi cant increase of apoptotic rates of [(24.9±1.4)%] in comparison with the other two groups whereas H460-RNAi cells showed almost no radiation (P0.05).The survival curve parameters D0,Dq,N,SF2 for H460 cells were 1.39,1.39,2.72,0.52,H460-Neg cells were 1.21,1.28,2.87,0.46 and for H460-RNAi cells were 0.97,0.75,2.18 and 0.26,all of which were signifi cantly lower than the other two groups.Conclusion:shRNA against the Bcl-2 mRNA inhibits Bcl-2 gene expression and enhances cell apoptosis and radiosensitivity of NCI-H460 cells.