Methylation Status of SP1 Sites within miR-23a-27a-24-2 Promoter Region Influences Laryngeal Cancer Cell Proliferation and Apoptosis.
DNA methylation plays critical roles in regulation of microRNA expression and function. miR-23a-27a-24-2 cluster has various functions and aberrant expression of the cluster is a common event in many cancers. However, whether DNA methylation influences the cluster expression and function is not reported. Here we found a CG-rich region spanning two SP1 sites in the cluster promoter region. The SP1 sites in the cluster were demethylated and methylated in Hep2 cells and HEK293 cells, respectively. Meanwhile, the cluster was significantly upregulated and downregulated in Hep2 cells and HEK293 cells, respectively. The SP1 sites were remethylated and the cluster was significantly downregulated in Hep2 cells into which methyl donor, S-adenosyl-L-methionine, was introduced. Moreover, S-adenosyl-L-methionine significantly increased Hep2 cell viability and repressed Hep2 cell early apoptosis. We also found that construct with two SP1 sites had highest luciferase activity and SP1 specifically bound the gene cluster promoter in vitro. We conclude that demethylated SP1 sites in miR-23a-27a-24-2 cluster upregulate the cluster expression, leading to proliferation promotion and early apoptosis inhibition in laryngeal cancer cells.
Department of Medical Genetics, China Medical University, Shenyang 110122, China.
Ye
Y
Wang
Department of Medical Genetics, China Medical University, Shenyang 110122, China.
Zhao-Xiong
ZX
Zhang
Department of Medical Genetics, China Medical University, Shenyang 110122, China.
Sheng
S
Chen
Department of Laboratory Medicine, No. 202 Hospital of PLA, Shenyang 110003, China.
Guang-Bin
GB
Qiu
Department of Otolaryngology, No. 463 Hospital of PLA, Shenyang 110007, China.
Zhen-Ming
ZM
Xu
Department of Medical Genetics, China Medical University, Shenyang 110122, China.
Wei-Neng
0000-0002-9191-8372
WN
Fu
D017209:Apoptosis / Q000235:genetics; D049109:Cell Proliferation / Q000235:genetics; D019175:DNA Methylation / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic; D057809:HEK293 Cells; D006801:Humans; D007822:Laryngeal Neoplasms / Q000235:genetics* / Q000473:pathology; D035683:MicroRNAs / Q000096:biosynthesis* / Q000235:genetics; D011401:Promoter Regions, Genetic; D016329:Sp1 Transcription Factor / Q000235:genetics*
C552430:MIRN23a microRNA, human; C543845:MIRN24 microRNA, human; C531388:MIRN27 microRNA, human; D035683:MicroRNAs; D016329:Sp1 Transcription Factor; C108209:SP1 protein, human