RNA interference is a major discovery in the field of the regulation of gene expression in recent years. It is an economic, fast, and efficient technological means in inhibiting gene expression. The incidence of lung cancer has been increasing year by year all over the world. In the last ten years, it has been the first cause of cancer deaths. In the treatment of lung cancer, the targeted gene therapy has become a research hotspot. As a powerful tool for gene therapy,RNA interference can inhibit cancer cell growth, induce apoptosis in lung cancer cells, and enhance their sensitivity to chemotherapy or radiotherapy by effectively silencing proto-oncogenes,apoptosis-related genes,cell cycle-related genes,growth factors,and drug resistance genes. RNA interference has been widely used in gene therapy of lung cancer, and has a significant anticancer effect.

Objective To establish a nude mouse model by subcutaneous injection of SPC-A-1 cell line,it was a useful tool for the in vivo research of lung adenocarcinoma.Methods 2×106 SPC-A-1 cell suspention was subcutaneously injected into the armpit of five BALB/c nude mice in each mouse,then the formation of transplanted tumors was studied,its glowth velocity,weight of transplanted tumors and the morphous were closely observed.Results Transplanted tumors were formed in all nude mice.The average time of their formation was about 7 days.The average long diameter and short diameter of these tumors were about(19.20±3.85)mm and(14.94±2.78)mm respectively 28 days later,and the average volume of them was calculated to be about(2 144.10±1 237.72)mm3.The average weight was calculated to be about(1.37±0.6)g.Most transplanted tumors showed a continuous membrane,the tumor cells showed a same morphology of adenocarcinoma cells,and focal necrsis was found in some transplanted tumors by microscope.Conclusion The nude mouse model were successfully established by subcutaneous injection of SPC-A-1 cell line,it would provide a useful tool in the following research in vivo.