Transcriptional regulation of miR-196b by ETS2 in gastric cancer cells.
E26 transformation-specific sequence (ETS)-2 is a transcriptional modulator located on chromosome 21, alterations in its expression have been implicated with a reduced incidence of solid tumors in Down syndrome patients. MicroRNAs (miRNAs) are thought to participate in diverse biological functions; however, the regulation of miRNAs is not well characterized. Recently, we reported that miR-196b is highly expressed in gastric cancers. Herein, we demonstrate that miR-196b expression was significantly repressed by ETS2 during gastric cancer oncogenesis. We demonstrate that knockdown of endogenous ETS2 expression increases miR-196b expression. A genomic region between -751 and -824 bp upstream of the miR-196b transcriptional start site was found to be critical for the repression activity. This putative regulatory promoter region contains three potential ETS2-binding motifs. Mutations within the ETS2 binding sites blocked the repression activity of ETS2. Furthermore, knockdown of ETS2 or overexpression of miR-196b significantly induced migration and invasion in gastric cancer cells. In addition, alterations in ETS2 and miR-196b expression in gastric cancer cell lines affected the expression of epithelial-mesenchymal transition-related genes. The levels of vimentin, matrix metalloproteinase (MMP)-2 and MMP9 were drastically induced, but levels of E-cadherin were decreased in shETS2- or miR-196b-transfected cells. Our data indicate that ETS2 plays a key role in controlling the expression of miR-196b, and miR-196b may mediate the tumor suppressor effects of ETS2. We demonstrated that miR-196b was transcriptionally regulated by ETS2 and there was an inverse expression profile between miR-196b and ETS2 in clinical samples. This finding could be beneficial for the development of effective cancer diagnostic and alternative therapeutic strategies.
Institute of Biomedical Sciences, Academic Sinica, Nankang, Taipei 115, Taiwan, Republic of China.
Yu-Lun
YL
Liao
Ling-Yueh
LY
Hu
Kuo-Wang
KW
Tsai
Chew-Wun
CW
Wu
Wen-Ching
WC
Chan
Sung-Chou
SC
Li
Chun-Hung
CH
Lai
Meng-Ru
MR
Ho
Wen-Liang
WL
Fang
Kuo-Hung
KH
Huang
Wen-Chang
WC
Lin
D001483:Base Sequence; D045744:Cell Line, Tumor; D047369:Chromatin Immunoprecipitation; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D035683:MicroRNAs / Q000235:genetics*; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D050787:Proto-Oncogene Protein c-ets-2 / Q000502:physiology*; D034622:RNA Interference; D012689:Sequence Homology, Nucleic Acid; D013274:Stomach Neoplasms / Q000235:genetics* / Q000473:pathology; D014158:Transcription, Genetic
C494069:ETS2 protein, human; C542543:MIRN196 microRNA, human; D035683:MicroRNAs; D050787:Proto-Oncogene Protein c-ets-2