Association between methylation status of apoptosis-related genes and chemosensitivity of lung adenocarcinoma cell line P15

AIM: To investigate the association between methylation status of apoptosis-related genes and chemosensitivity in the lung adenocarcinoma cell line P15.METHODS: Methylation-specific PCR was applied to detect the methylation status of p73, p14^ARF, p16^INK4a and bax genes of P15 cells in untreated control group and decitabine (DAC) treatment group. RT-PCR was used to detect the expression of p73, bcl-xL, bad, bax, p14^ARF and p16^INK4a at mRNA level. Colony formation assay and cell growth inhibition assay were used to detect the sensitivity of P15 cells to cis-diaminedichloroplatinum (C-DDP) before and after DAC treatment. DAPI staining was used to determine the apoptosis of P15 cells exposed to C-DDP before and after DAC treatment. RESULTS: p73, p16^INK4a and bax were expressed in the methylation status. After DAC treatment, p16^INK4a expression was decreased, and the expression of p73 and bax disappeared. The expression of p73, p16^INK4a and bax in the unmethylated status was weak, but the enhanced expression was observed following DAC treatment. After P15 cells were treated with DAC and C-DDP, the colony formation rate of the P15 cells was significantly decreased as compared with untreated control group. The apoptotic P15 cells in DAC+C-DDP treatment group were significantly higher than those in untreated control group (P<0.05). CONCLUSION: After treated with DAC, the sensitivity of P15 cells to C-DDP is increased due to the activation of silenced pro-apoptotic genes. DAC and C-DDP synergistically promote tumor cell apoptosis. They have significant anti-tumor effect.