Reduced miR-100 expression in cervical cancer and precursors and its carcinogenic effect through targeting PLK1 protein

• Published in: European journal of cancer (1990) 2011-09, Vol.47 (14), p.2166-2174
• Main Authors: Li, Bao Hua, Zhou, Jian Song, Ye, Feng, Cheng, Xiao Dong, Zhou, Cai Yun, Lu, Wei Guo, Xie, Xing
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Biomarkers, Tumor - metabolism; Case-Control Studies; Cell Cycle Proteins - metabolism; Cell Transformation, Neoplastic - metabolism; Cells, Cultured; Cervical carcinogenesis; Cervix Uteri - cytology; Cervix Uteri - metabolism; Double-Blind Method; Epithelial Cells - metabolism; Female; Hematology, Oncology and Palliative Medicine; Human papillomavirus; Human papillomavirus 16 - metabolism; Humans; Medical sciences; MicroRNAs - metabolism; miR-100; Oncogene Proteins, Viral - metabolism; Papillomavirus E7 Proteins - metabolism; Pharmacology. Drug treatments; PLK1; Polo-Like Kinase 1; Protein Serine-Threonine Kinases - metabolism; Proto-Oncogene Proteins - metabolism; Reference Values; Repressor Proteins - metabolism; Signal Transduction - physiology; Tumors; Uterine Cervical Dysplasia - metabolism; Uterine Cervical Neoplasms - metabolism; Viral oncoproteins
• ISSN: 0959-8049; 1879-0852
• DOI: 10.1016/j.ejca.2011.04.037

Abstract Aim 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.