Background & objective: C-erbB-2 gene is amplified or overexpressed in breast cancer, ovarian cancer, and lung cancer, and is related with enhanced malignancy and metastatic ability, intrinsic chemoresistance, and poor prognosis of tumors. RNA interfering (RNAi), a new genetic technique, can efficiently and specifically suppress gene expression. This study was to investigate the effect of small interfering RNA (siRNA)-mediated gene silencing of C-erbB-2 on proliferation of human lung adenocarcinoma cell line calu-3.
Methods: C-erbB-2 siRNA was transfected into calu-3 cells; cell morphology was observed under light microscope. The mRNA and protein levels of C-erbB-2 were detected by reverse transcription-polymerase chain reaction (RT-PCR) and flow cytometry (FCM). The proliferation of calu-3 cells was assessed by MTT assay. Cell cycle and apoptosis were analyzed by FCM.
Results: C-erbB-2 siRNA down-regulated the mRNA and protein levels of C-erbB-2 in calu-3 cells; 48 h after transfection of C-erbB-2 siRNA, the protein level of C-erbB-2 was markedly decreased. The positive rate of C-erbB-2 was significantly lower in C-erbB-2 siRNA group than in untransfected group, empty vector group, and nonspecific siRNA group [(25.04+/-1.56)% vs. (98.24+/-2.23)%, (95.67+/-1.98)%, and (94.79+/-0.87)%, P < 0.01]. C-erbB-2 siRNA inhibited proliferation of calu-3 cells: G(0)/G(1) phase proportion of C-erbB-2 siRNA group was significantly higher than that of untransfected group [(56.6+/-3.6)% vs. (45.5+/-3.2)%, P < 0.01]. C-erbB-2 siRNA also enhanced cell apoptosis.
Conclusion: Specific siRNA targeting C-erbB-2 can effectively inhibit C-erbB-2 expression and proliferation of calu-3 cells.