Down-regulation of miR-212 expression by DNA hypermethylation in human gastric cancer cells.
There has been few report discussing the expression and function of miR-212 in gastric cancer (GC). The aim of this pilot study was to investigate the expression of miR-212 in both gastric cancer tissues and gastric cancer cells and further explores the possible reasons for this change and the impact on the development of gastric cancer. qRT-PCR was used to detect the expression of miR-212 in primary GC tissues, adjacent normal tissues, gastric cancer cell lines BGC-823, SGC-7901, MKN-45, and normal gastric mucosa cell line GES. The expression of miR-212 was evaluated before and after treatment with methylation inhibitor-5-Aza-2'-deoxycitidine (5-Aza-dC), finally anti-miRNA and dual luciferase reporter assay were used to prove that MYC is a target gene of miR-212. The results showed that a significant reduction of miR-212 expression in GC tissues was observed compared to that in normal tissues (P = 0.002). At the same time, miR-212 expression level in normal gastric mucosa cell line GES was higher than that of in gastric cancer cell lines BGC-823, SGC-7901, and MKN-45 (P = 0.015, 0.008, 0.044, respectively). Computer sequence analysis showed the hypermethylation of CpG islands(CPI) in the promoter regions of miR-212 led to the lower expression of miR-212 in gastric cell strains (BGC-823 and SGC-7901). MiR-212 expression was significantly recovered after treatment with methylation inhibitor 5-Aza-dC (P = 0.016, 0.000, 0.015, respectively). Then, the results of AMOs transfection and dual luciferase reporter assay showed that Myc is a target of miR-212, which will be helpful to verify the function of miR-212 in carcinogenesis. The conclusion could be deduced from the study that decreased expression of miR-212 may be due to hypermethylation of CPI in gastric cancer cells, and miR-212 might act on the progression of gastric cancer through the potential target gene Myc.
Department of Gastroenterology, Tenth People's Hospital of Tongji University, Shanghai 200072, China.
Ling
L
Xu
Feng
F
Wang
Xuan-Fu
XF
Xu
Wen-Hui
WH
Mo
Yu-Jing
YJ
Xia
Rong
R
Wan
Xing-Peng
XP
Wang
Chuan-Yong
CY
Guo
D002460:Cell Line; D045744:Cell Line, Tumor; D019175:DNA Methylation / Q000502:physiology*; D015536:Down-Regulation / Q000502:physiology*; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D035683:MicroRNAs / Q000378:metabolism*; D010865:Pilot Projects; D013274:Stomach Neoplasms / Q000235:genetics / Q000378:metabolism*
C551411:MIRN212 microRNA, human; D035683:MicroRNAs