Breast Cancer Ndrg-1 Gene Methylation And 5 - Aza-2'-deoxycytidine T47d Cell Growth And Proliferation

Objective To investigate correlation between the methylation status of the NDRG-1 gene promoter and its mRNA expression in breast cancer, study the effects of 5-Aza-2'-deoxycytidine (5-Aza-CdR) on cell growth and expression of NDRG-1 mRNA in the human breast cancer cell line T47D.Methods The expression of NDRG-1 mRNA was examined by RT-PCR in breast neoplasm tissues. Sensitive methylation-specific 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,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 semi-quantitative RT-PCR method before and after 5-Aza-CdR treatment. Activity of cell growth was observed by MTT assay.Results The NDRG-1 mRNA. appeared in breast benign disease tissues, and the loss frequency was 57.4% (27/47) in breast cancers compared with 34.0%(16/47) in tumor-adjacent tissues. Among the 47 breast cancers, NDRG-1 hypermethylation was detected in 22 cases, and 10 cases of tumor-adjacent tissues. Hypermethylation frequencies of NDRG-1 gene promoter were 46.8% in breast cancer tissues and 21.3% in tumor-adjacent tissues, and there was no hypermethylation found in the tissues of breast benign disease. As the results showed that there no significant differences in methylation frequencies were seen between hypermethylation status and histological grade (P>0.5). Hypermethylation rates were higher in the lymph node metastasis than that of without lymph node metastasis (66.7% and 37.5%). The negative expression of NDRG-1mRNA breast cancer tissues were detected hypermethylation (16/27), which was significantly different to the positive samples (6/20). It was showed that the growth of T47D cells was restricted obviously in the experiment groups compared with control group. After treatment with 5-Aza-CdR, NDRG-1mRNA expressions were increased, which were higher than before treatment.Conclusion The promoter methylation of NDRG-1 is significantly related with the occurrence of breast carcinoma, and it may contribute to the loss of NDRG-1mRNA expression.5-Aza-CdR may effectively cause reversion of NDRG-1mRNA expression, and treatment with 5-Aza-CdR can reactivate the expression of the gene and inhibit the cell growth.