miR-31 functions as an oncogene in cervical cancer

Background MicroRNAs are frequently altered in numerous cancers and are critical regulators of various diseases. miR-31 has been shown to be significantly altered in a variety of cancers. Methods In the present study, we measured the expression level of miR-31 in cervical cancer, CIN and normal cervical tissues by real-time RT (reverse transcription)-PCR. We also analyzed the correlations between the expression level of miR-31 and the clinical characteristics in cases of cervical squamous cell carcinoma. In addition, we measured the expression of miR-31 in cervical cancer cell lines, and transfected HPV16 E6 siRNA and HPV16 E7 siRNA into SiHa cells to investigate the effects on miR-31. Finally, the effects of miR-31 on cell proliferation, migration and invasion were measured in HeLa and SiHa cells that were transfected with a miR-31 mimic or a negative control. Result We found that the expression level of miR-31 was significantly higher in cervical cancer patients than in normal individuals (P < 0.05). Aberrant expression of miR-31 was positively correlated with the lymph node metastasis (LNM), vessel invasion and HPV status (P < 0.05). Additionally, miR-31 was also overexpressed in the cervical cancer-derived HeLa and SiHa cells compared with C33A cells (P < 0.05). Moreover, a relationship was found between miR-31 expression and the HPV16 oncoproteins E6/E7. Furthermore, we found that the overexpression of miR-31 can promote cell proliferation and enhance the migration and invasion abilities of cancer cells. Conclusions Our results suggested that miR-31 plays an oncogenetic role in the development and progression of cervical cancer.