ABSTRACT
AIM:Toinvestigatetheassociationbetweenmethylationstatusofapoptosis-relatedgenesandche-mosensitivity in the lung adenocarcinoma cell line P 15.METHODS: Methylation-specific PCR was applied to detect the methylation status of p73, p14ARF, p16INK4a and bax genes of P15 cells in untreated control group and decitabine (DAC) treatment group.RT-PCR was used to detect the expression of p 73, bcl-xL, bad, bax, p14ARF and p16INK4a at mRNA level. Colony formation assay and cell growth inhibition assay were used to detect the sensitivity of P 15 cells to cis-diaminedichlo-roplatinum ( C-DDP) before and after DAC treatment .DAPI staining was used to determine the apoptosis of P 15 cells ex-posed to C-DDP before and after DAC treatment .RESULTS:p73, p16INK4a and bax were expressed in the methylation sta-tus.After DAC treatment, p16INK4a expression was decreased , and the expression of p73 and bax disappeared .The expres-sion of p73, p16INK4a 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 signifi-cantly 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 sensi-tivity of P15 cells to C-DDP is increased due to the activation of silenced pro-apoptotic genes .DAC and C-DDP synergisti-cally promote tumor cell apoptosis .They have significant anti-tumor effect .