Effect of RNAi inhibition to expression of CD44 and CD133 on tumorigenesis of human lung adenocarcinoma cell line A549

Objective To study the effect of expression of CD44 and CD133 on the tumorigenesis of human lung adenocarcinoma cell line A549. Methods A549 cells having continuous self-renewal ability were cultured, and classified into 5 subpopulations based on differential expression patterns for CD133and CD44. The small interfering RNA (siRNA) with optimal sequences was screened out, and transfected the A549 cells. The methods of MTS and cell counting were used to investigate the proliferation of A549cells before and after the expression of CD133 and CD44 was inhibited by RNAi. Results For the optimal sequences and concentrations for siRNA transfection efficiency being 25 nmol/L for both siCD44-h_002 25and siCD133-h_002 25, the transfection efficiency was 62% and 82% respectively. Stably transfected cells were screened, and the expression of CD44 and CD133 was inhibited significantly. The gray values before transfection were significantly different from those after transfection ( P ＜ 0. 01 ). The MTS curve showed that the cell viability was significantly decreased after transfection. Conclusion The proliferation ability of A549 cells was related to the positive expression of CD44 and CD133. CD133 and CD44 may be important surface markers of lung cancer stem cells. Key words: RNAi; Lung carcinoma; CD133; CD44