锯齿状病变患者组织中CDX2基因启动子中上游区域的甲基化

Effect of 5'-Aza-2'-deoxycytidine on methylation, mRNA and protein expression of CDX2 gene in colorectal cancer HT-29 and LoVo cells

AIM: To investigate the effect of 5'-Aza-2'-deoxycytidine (5'-Aza-CdR), a methylation inhibitor, on the methylation, mRNA and protein expression of the CDX2 gene in colorectal ancer cell lines HT-29 and LoVo.

METHODS: HT-29 and LoVo cells were treated with different dosages of 5'-Aza-CdR. After treatment, CDX2 gene methylation was determined by Methylight assay, and CDX2 mRNA and protein expression was detected by real-time PCR and Western blot, respectively.

RESULTS: Methylight assay showed that CDX2 gene methylation was not reversed by 5'-Aza-CdR. The expression levels of CDX2 mRNA were increased in both HT-29 (1.000 ± 0.000, 0.973 ± 0.024, 1.014 ± 0.019 and 1.094 ± 0.020, respectively) and LoVo cells (1.000 ± 0.000, 0.966 ± 0.038, 1.050 ± 0.029 and 1.007 ± 0.019, respectively) cells treated with 5'-Aza-CdR for different durations. Western blot analysis indicated that 5'-Aza-CdR treatment could recover the CDX2 protein expression in both HT-29 (0.454 ± 0.049, 0.501 ± 0.041, 0.340 ± 0.050 and 0.531 ± 0.046, respectively) and LoVo (0.527 ± 0.037, 0.415 ± 0.037, 0.432 ± 0.040 and 0.626 ± 0.046, respectively) cells. The effect of 5'-Aza-CdR on CDX2 mRNA and protein expression was not dose- or time-dependent, but the expression levels of CDX2 mRNA and protein differed significantly in HT-29 (mRNA: F = 25.146, P = 0.000; protein: F = 9.700, P = 0.005) and LoVo cells (mRNA: F = 5.470, P = 0.024; protein: F = 17.701, P = 0.001).

CONCLUSION: CDX2 mRNA and protein expression is not affected by DNA methylation in HT-29 and LoVo cells.