Abstract: Objective To investigate the changes of the proliferation and apoptosis of lung adenocarcinoma cell A549 to IGF-1R specific RNA interference and its sensitivity to Trail. Methods The IGF-1R specific siRNA transcription template was chemically synthesized and connected to the siRNA expression vector.The restructured expression vector was transfected into E.coli.Amplified vector was extracted.Enzyme digestion and DNA sequencing were used to prove that the expression vector was successfully constructed.Stable expression of IGF-1R-siRNA A549 cell lines were screened by G418.FQ RT-PCR,Western blot and immunohistochemistry were used to detect inhibitory effect.Before and after the Trail treatment,MTT and flow cytometry were used to test proliferation and apoptosis of A549 cells. Results DNA sequencing results proved the successful construction of IGF-1R-siRNA expression vector.The selected monoclonal cells with stable expression of IGF-1R-siRNA decreased IGF-1R mRNA and protein expression by 79.01%(0.17±0.06 vs. 0.81±0.15,P<0.01) and 76.05%(1.36±0.26 vs. 5.68±0.45,P<0.01)than that of control A549 cells.Immunohistochemistry also showed a lower expression of IGF-1R. After treatment of Trail on A549 with IGF-1R-siRNA, the cell proliferation rate decreased(P<0.05); the apoptosis rate was obviously increased(P<0.01). Conclusion The constructed IGF-1R-siRNA expression vector can decrease the expression of IGF-1R gene in A549 cells.IGF-1R-siRNA can effectively inhibit the proliferation and enhance the Trail induced apoptosis in lung cancer cell A549.