MicroRNA-21 promotes cell metastasis in cervical cancer through modulating epithelial-mesenchymal transition

MicroRNA (miR)-21 is known to act as an oncogene in cervical cancer by promoting cell proliferation and migration; however, the underlying molecular mechanisms have remained to be fully elucidated. The present study revealed that the gene expression levels of miR-21 and epithelial-mesenchymal transition (EMT)-associated transcription factor Zinc finger E-box-binding homeobox 1 (ZEB1), in cervical cancer and lymphatic metastatic carcinoma tissues were significantly higher than those in normal tissues (P<0.05). Furthermore, the gene expression levels of miR-21 and ZEB1 were positively associated with muscular infiltration depth, parametrical invasion and lymph node metastasis in patients with cervical cancer. Immunohistochemistry assays indicated that the expression levels of ZEB1 and the mesenchymal cell marker Vimentin in cervical cancer tissues were significantly higher than those in normal cervical tissues (P<0.05). Overexpression of miR-21 in HeLa and SiHa cells caused the upregulation of the mesenchymal cell markers Vimentin and N-cadherin, and downregulation of the epithelial cell marker E-cadherin at the proteins level. In addition, overexpression of miR-21 enhanced the invasiveness of HeLa and SiHa cells. These results demonstrated that miR-21 was upregulated in cervical cancer tissues and promoted cell metastasis through modulating EMT. A better understanding of the role of miR-21 and EMT may lead to the development of more effective therapies for patients with cervical cancer.