PO-388 Epigenetic silencing of ZNF177 by MIR-877–3 p could be involved in cervical cancer progression

Introduction Cervical cancer (CC) is the fourth most common cancer among women worldwide, with around 50% of mortality. Therefore, new prognostic biomarkers are necessary to improve its poor outcome. Micro-RNAs (miRs) are small non-coding RNAs, mainly associated with gene expression silencing, and deregulated in cancer. Our aim was to identify miRs which are differentially expressed in several stages of CC progression and with clinical value, in order to point them out as biomarkers in CC. Material and methods A series of formalin-fixed and paraffin-embedded cervical tissues was used: 48 invasive tumours, 46 high-grade squamous intraepithelial lesions (HSILs-CIN3) and 20 benign lesions of the cervical epithelium. The expression levels of miR-141–5 p, miR-188–5 p, miR-196–5 p, and miR-877–3 p were measured by quantitative RT-PCR (qRT-PCR), using RNU48 as endogenous control. Since TargetScan database predicted the ZNF177 gene as a target of miR-141–5 p and miR-877–3 p, its expression was analysed by immunohistochemistry. Three CC cell lines (C-33A, HeLa and SiHa) were transfected with anti-miR-877, and effects on miR and protein expression were measured by qRT-PCR and Western blot, respectively. Moreover, transfected cells were fixed and stained with crystal violet to determine the effects on cell proliferation and migration. Results and discussions We found that the expression levels of all miRs, but miR-141, were significantly higher in invasive tumours and HSIL-CIN3 than in benign lesions (p in vitro transfection of anti-miR-877 decreased and increased miR-877 and ZNF177 protein levels, respectively, and impaired cell migration in all 3 cell lines. This is the first study that proposes a functional role of the unknown ZNF177. Conclusion Invasive cervical tumours and HSIL-CIN3 lesions display a different miR expression pattern compared to benign lesions of the cervical epithelium, as overexpression of miR-188–5 p, miR-196–5 p, and miR-877–3 p. Nuclear expression of ZNF177, a target of miR-877–3 p, is a biomarker of poor outcome in CC patients. Inhibition of miR-877–3 p leads to ZNF177 upregulation and impairment of CC cell migration.