Relationship between the overexpression of DNA methyltransferase 3B4 and clear cell renal cell carcinoma / 中国肿瘤临床

ABSTRACT

Objective:To determine the molecular role of DNA methyltransferase (DNMT) in kidney tumorigenesis. Methods:Tissue samples consisted of 15 cancer tissues and 15 matched adjacent tissues from clear cell renal cell carcinoma (ccRCC) patients who had undergone nephrectomy in 2012 at the First Affiliated Hospital of Baotou Medical College, Science and Technology University of Inner Mongolia were collected. Real-time PCR, Western blot, combined bisulfite restriction analysis (COBRA) and methylation specific PCR were used in this study. Real-time PCR was used to examine the mRNA expression levels of DNMT. The global methylation level, DNA methylation level, and the expression of the antioncogene RASSF1A in ccRCC tissues were concurrently detected. Results:Both mRNA and protein levels of DNMT3B4, a splice variant of DNMT3B, were elevated in renal cell carcinoma tissue compared with those in con-troll tissue. Additionally, Alu was hypomethylated in ccRCC tissue (0.106±0.04) compared with control tissue (0.115±0.03) (P<0.05). Fur-thermore, the methylation of the promoter for RASSF1A, a tumor-suppressor gene, moderately increased in renal cell carcinoma tis-sue. By contrast, RASF1A expression decreased. Conclusion:DNMT3B4 overexpression may play an important role in human kidney tu-morigenesis via chromosomal instability and the decreased expression of RASSF1A.