Background: p53 gene is the most commonly mutated gene in lung cancer. p53 mutation results in insensitivity of cells when exposed to chemotherapy. It has been reported that adenovirus-mediated wild-type p53 gene transfection into lung cancer cells can enhance the cytotoxic effect of anti-cancer drugs. The aim of this study is to evaluate the effects of domestic recombinant adenovirus-p53 (Ad-p53, Gendicine) on growth and chemosensitivity of human lung adenocarcinoma cell lines.
Methods: Human lung adenocarcinoma cell lines GLC-82 (including mutant p53) and A549 (including wild-type p53) were treated with Ad-p53, cisplatin (DDP) or Ad-p53+DDP respectively. p53 expression was detected by Western blot. The cell growth inhibition was assessed by MTT, and cell cycle and apoptosis were detected by flow cytometry.
Results: High-level p53 expression was detected in Ad-p53 infected GLC-82 and A549 cells by Western blot. There was a dose-dependent and time-dependent inhibition of cell proliferation by Ad-p53. After combined treatment with Ad-p53 (100MOI) and DDP (0.5mg/L) for 72h, the growth inhibition rate of A549 cells was 43.13%±0.72%, which was significantly higher than that in Ad-p53 group ( 23.44%±0.54%, P < 0.001) and DDP group (14.17%±1.39%, P < 0.001); and the growth inhibition rate of GLC-82 cells was 63.73%±0.92%, which was significantly higher than that in Ad-p53 group ( 41.51%±0.59%, P < 0.001) and DDP group (56.11%±1.12%, P < 0.001). Combined administration of Ad-p53 and DDP remarkably arrested A549 and GLC-82 cells in G0-G1, and cells in S phase significantly decreased. Meanwhile the apoptotic rate of A549 cells was 28.99%±1.07% in Ad-p53+DDP group, which was significantly higher than that in Ad-p53 group (15.35%±1.31%, P < 0.001) and DDP group (1.74%±0.77%, P < 0.001). The apoptotic rate of GLC-82 cells was 62.98%±2.43% in Ad-p53+DDP group, which was significantly higher than that in Ad-p53 group (20.88%±0.71%, P < 0.001) and DDP group (6.91%±1.52%, P < 0.001).
Conclusions: Ad-p53 (Gendicine) can inhibit the growth of human lung adenocarcinoma cell lines irrespective of the status of endogenous p53 gene. Its combination with DDP may significantly enhance the chemosensitivity of human lung adenocarcinoma cells to DDP.