Study on the methylation status of NDRG-1 gene in breast cancer and its reversion in vitro / 肿瘤

ABSTRACT

Objective:To investigate the methylation status of N-myc downstream regulated gene-1(NDRG-1) gene in breast cancer and the effects of methylation enzyme inhibitor 5-Aza-2'-deoxycytidine (5-Aza-CdR) on growth and expression of NDRG-1 mRNA in human breast cancer cell line T47D.Methods:Sensitive methylation-specific (MSP)-PCR was used to detect the methylation status in the promoter regions of NDRG-1 gene in 47 samples of breast cancer and tumor adjacent tissues and 15 cases of benign breast disease. The change in expression of the tumor suppressor gene NDRG-1 mRNA in cultured T47D cells was detected by RT-PCR before and after 5-Aza-CdR treatment. Cell proliferation was observed by MTT assay.Results:Hypermethylation frequencies of NDRG-1 gene promoter were 46.8% in breast cancer tissues and 21.3% in tumor adjacent tissues. No hypermethylation of NDRG-1 gene was observed in the tissues of breast benign disease. The growth of T47D cells was suppressed obviously after 5-Aza-CdR treatment compared with the control group. RT-PCR showed that compared with the control group, NDRG-1 mRNA expression was increased at different concentrations in 5-Aza-CdR treatment group. Conclusion:The promoter methylation status of NDRG-1 gene was significantly related with the occurrence of breast carcinoma. 5-Aza-CdR could effectively reverse the methylation of NDRG-1 gene and recover its expression, thereby inhibiting the growth of tumor cells.