title: Methylation-mediated repression of microRNA 129-2 enhances oncogenic SOX4 expression in HCC.
abstract: OBJECTIVE
  Aberration of miR-129-2 has been linked to a variety of human tumours. However, whether miR-129-2 is involved in hepatocarcinogenesis remains unknown. Here, we investigate the involvement of miR-129-2 in HBV infection-related HCC.
  
  
  METHODS
  A total of 75 paired tumour and their corresponding non-tumour liver tissues from HCC patients with serum HBsAg positive were collected. The methylation of miR-129-2 gene was quantitatively analysed by a DNA methylation-sensitive endonuclease digestion followed by quantitative PCR. The expression of mature miR-129-2 (miR-129-3p) was detected by Taqman RT-PCR. SOX4 expression was detected using quantitative realtime RT-PCR, western blot and immunohistochemical staining. The function of miR-129-2 was investigated using cell proliferation and clonogenicity assays in vitro.
  
  
  RESULTS
  Compared with the adjacent non-tumour tissues, tumour tissues exhibited significantly increased miR-129-2 hypermethylation both in frequency (37.33% vs. 8%, P < 0.0001) and in intensity (14.77% vs. 3.08%, P = 0.002). Accordantly, miR-129-3p expression in HCC tissues was significantly lower than that in non-tumour tissues (P = 0.0461), in a manner reversely correlated with the level of miR-129-2 hypermethylation. Notably, SOX4 level in the HCC tissues was significantly higher than that in non-tumour tissues (P = 0.0174) and normal liver tissues (P = 0.0077), correlated reversely with miR-129-3p level (P = 0.0105). Furthermore, overexpression of miR-129-2 in HepG2 reduced cell proliferation and clonogenicity, while co-expression with SOX4 could partially reverse its antitumor effects. In addition, SOX4 in HepG2 cell can enhance β-catenin/TCF activity by increasing β-catenin level.
  
  
  CONCLUSIONS
  The current data indicated that methylation-mediated repression of miR-129-2 may enhance oncogenic SOX4 expression and involve in HCC tumorigenesis.
authors: Department of Microbiology & Infectious Disease Center, School of Basic Medical Science, Peking University Health Science Center, Beijing, China.
authors: Xiangmei
authors: X
authors: Chen
authors: Ling
authors: L
authors: Zhang
authors: Ting
authors: T
authors: Zhang
authors: Meili
authors: M
authors: Hao
authors: Xiaolei
authors: X
authors: Zhang
authors: Jiangbo
authors: J
authors: Zhang
authors: Qing
authors: Q
authors: Xie
authors: Yongfeng
authors: Y
authors: Wang
authors: Mingzhou
authors: M
authors: Guo
authors: Hui
authors: H
authors: Zhuang
authors: Fengmin
authors: F
authors: Lu
mesh_terms: D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000209:etiology / Q000378:metabolism*; D019175:DNA Methylation; D017931:DNA Primers / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic / Q000502:physiology*; D056945:Hep G2 Cells; D006509:Hepatitis B / Q000150:complications*; D006801:Humans; D007150:Immunohistochemistry; D008113:Liver Neoplasms / Q000209:etiology / Q000378:metabolism*; D035683:MicroRNAs / Q000037:antagonists & inhibitors*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055751:SOXC Transcription Factors / Q000378:metabolism*
chemical_list: D017931:DNA Primers; D035683:MicroRNAs; C541915:Mirn129 microRNA, human; C083431:SOX4 protein, human; D055751:SOXC Transcription Factors