407008

MIR223

Accumulating evidence have emerged important roles for microRNAs (miRNAs) participating in epithelial-mesenchymal transition (EMT) process and are associated with metastasis in cervical cancer. We hypothesized that miR-223 played an important role in cell metastasis of cervical cancer. Here, we found miR-223 was downregulated in human cervical cancer cell lines and clinical tumor tissues. Result of wound healing and cell migration assays revealed that miR-223 inhibited cell migration, whereas miR-223-in showed the opposite effect. In terms of mechanism, miR-223 influenced the expression of the EMT-associated proteins by upregulating the epithelial markers E-cadherin and alpha-cadherin and downregulating the mesenchymal marker vimentin. In conclusion, miR-223 inhibited cell metastasis of human cervical cancer by modulating epithelial-mesenchymal transition.

Sp1 plays critical roles in epithelial-mesenchymal transition (EMT) of certain cancer. However, few studies have indicated whether Sp1 is involved in the EMT of gastric cancer, and whether abnormal expression of Sp1 in gastric cancer EMT is regulated in a post-transcriptional manner, and the involvement of miRNAs in this regulation. In this study, we selected 20 cases of gastric cancers, their liver metastases and para-carcinoma tissues to examine the levels of Sp1 protein and mRNA by immunohistochemistry and fluorescent PCR, which showed that Sp1 was increased in gastric cancers and their metastases compared with adjacent tissues, but there was no difference in Sp1 mRNA between these three groups, suggesting changes in Sp1 may be attributed to inactivation of post-transcriptional regulation. We verified by a luciferase reporter system that miRNA-223 binds to 3'-UTR of Sp1 gene and inhibits its translation, in agreement with negative correlation between miRNA-223 and Sp1 protein levels in gastric cancer cells. By employing TGF-beta1 to induce MGC-803, BGC-823 and SGC-7901, we successfully built cellular EMT model. Then, we overexpressed miRNA-223 in the model by using a lentiviral system, which diminished EMT indicators and suppressed proliferation and invasion ability, and induced apoptosis. Finally, we verified the specificity of the regulation pathway miRNA-223/Sp1/EMT. These findings suggest that low expression of miRNA-223 in gastric cancer cells is an important cause for EMT. miRNA-223 specifically regulates the EMT process of gastric cancer cells through its target gene Sp1. Overexpression of miRNA-223 in these cells inhibits EMT via the miRNA-223/Sp1/EMT pathway.