title: Reduced miR-100 expression in cervical cancer and precursors and its carcinogenic effect through targeting PLK1 protein.
abstract: OBJECTIVE
  Although aberrant miRNAs expression has been documented, altered miR-100 expression in cervical cancer and precursor tissues and its carcinogenic effect and mechanism remain unexplored. The aim of our study was to investigate the role of miR-100 alteration in cervical carcinogenesis.
  
  
  METHODS
  The expression of miR-100 was examined by quantitative real-time reverse transcriptase PCR (qRT-PCR) in 125 cervical tissues including normal cervical epithelium, cervical intraepithelial neoplasia (CIN), and cervical cancer, as well as in five cervical cell lines. Through modulating miR-100 expression using miR-100 inhibitor or mimic in vitro, cell growth, cycle and apoptosis were tested separately by MTT or flow cytometry and meanwhile Polo-like kinase1 (PLK1) mRNA and protein expressions were detected by qRT-PCR and immunoblotting. The expression of PLK1 in 125 cervical tissues was also examined by immunohistochemical staining and the correlation between miR-100 and PLK1 expression in the same tissues was analysed. Finally, HPV-16 E6/E7 expression was modulated by gene transfection and subsequently the level of miR-100 was examined by qRT-PCR.
  
  
  RESULTS
  The miR-100 expression showed a significantly and gradually reduced tendency from low-grade CIN, high-grade CIN to cervical cancer tissues and a significant decrease in HPV positive cervical cancer cell lines. The modulation of miR-100 expression remarkably influenced cell proliferation, cycle and apoptosis, as well as the level of PLK1 protein, but not mRNA, in vitro experiments. PLK1 expression was negatively correlated with miR-100 expression in CIN3 and cervical cancer tissues. The modulation of HR-HPV E6/E7 expression did not change miR-100 level.
  
  
  CONCLUSIONS
  The reduced miR-100 expression participates in the development of cervical cancer at least partly through loss of inhibition to target gene PLK1, which probably occurs in a relative late phase of carcinogenesis. HR-HPV E6/E7 may not directly regulate miR-100 expression in cervical cells.
authors.affiliation: Women's Reproductive Health Key Laboratory of Zhejiang Province, Department of Gynecologic Oncology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Bao Hua
authors.initials: BH
authors.lastname: Li
authors.forename: Jian Song
authors.initials: JS
authors.lastname: Zhou
authors.forename: Feng
authors.initials: F
authors.lastname: Ye
authors.forename: Xiao Dong
authors.initials: XD
authors.lastname: Cheng
authors.forename: Cai Yun
authors.initials: CY
authors.lastname: Zhou
authors.forename: Wei Guo
authors.initials: WG
authors.lastname: Lu
authors.forename: Xing
authors.initials: X
authors.lastname: Xie
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism*; D016022:Case-Control Studies; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002471:Cell Transformation, Neoplastic / Q000378:metabolism*; D002478:Cells, Cultured; D002584:Cervix Uteri / Q000166:cytology / Q000378:metabolism; D004311:Double-Blind Method; D004847:Epithelial Cells / Q000378:metabolism; D005260:Female; D052162:Human papillomavirus 16 / Q000378:metabolism; D006801:Humans; D035683:MicroRNAs / Q000378:metabolism*; D009856:Oncogene Proteins, Viral / Q000378:metabolism; D050725:Papillomavirus E7 Proteins / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D012016:Reference Values; D012097:Repressor Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D002583:Uterine Cervical Neoplasms / Q000378:metabolism*; D002578:Uterine Cervical Dysplasia / Q000378:metabolism*; D000097869:Polo-Like Kinase 1
chemical_list: D014408:Biomarkers, Tumor; D018797:Cell Cycle Proteins; D035683:MicroRNAs; D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D012097:Repressor Proteins; D000097869:Polo-Like Kinase 1; C068651:E6 protein, Human papillomavirus type 16; C544266:MIRN100 microRNA, human; C059731:oncogene protein E7, Human papillomavirus type 16