miR-196a targets netrin 4 and regulates cell proliferation and migration of cervical cancer cells

Recent research has uncovered tumor-suppressive and oncogenic potential of miR-196a in various tumors. However, the expression and mechanism of its function in cervical cancer remains unclear. In this study, we assess relative expression of miR-196a in cervical premalignant lesions, cervical cancer tissues, and four cancer cell lines using quantitative real-time PCR. CaSki and HeLa cells were treated with miR-196a inhibitors, mimics, or pCDNA/miR-196a to investigate the role of miR-196a in cancer cell proliferation and migration. We demonstrated that miR-196a was overexpressed in cervical intraepithelial neoplasia 2-3 and cervical cancer tissue. Moreover, its expression contributes to the proliferation and migration of cervical cancer cells, whereas inhibiting its expression led to a reduction in proliferation and migration. Five candidate targets of miR-196a chosen by computational prediction and Cervical Cancer Gene Database search were measured for their mRNA in both miR-196a-overexpressing and -depleted cancer cells. Only netrin 4 (NTN4) expression displayed an inverse association with miR-196a. Fluorescent reporter assays revealed that miR-196a inhibited NTN4 expression by targeting one binding site in the 3'-untranslated region (3'-UTR) of NTN4 mRNA. Furthermore, qPCR and Western blot assays verified NTN4 expression was downregulated in cervical cancer tissues compared to normal controls, and in vivo mRNA level of NTN4 inversely correlated with miR-196a expression. In summary, our findings provide new insights about the functional role of miR-196a in cervical carcinogenesis and suggested a potential use of miR-196a for clinical diagnosis and as a therapeutic target.