miR-205 regulates A549 cells proliferation by targeting PTEN.

miR-205 is an epithelial-specific miRNA and has been shown to orchestrate some cellular processes such as epithelial mesenchymal transition (EMT) and differentiation fate of stem cells in mammary gland. miR-205 play a part of a tumor suppressor in human cancers. However, the role of miR-205 in lung cancer is unclear. In this study, we detected the expression level of miR-205 in 46 cases clinical lung cancer specimens and adjacent normal tissues by stem-loop RT-PCR. We found that the expression of miR-205 was significantly increased in lung cancer specimens compared to adjacent normal tissues (P < 0.01). Furthermore, we observed the expressions of PTEN protein and mRNA in lung cancer tissues and adjacent normal tissues by methods of western blot and Real time PCR respectively. We found that the expressions of PTEN protein and mRNA was significantly decreased in lung cancer specimens compared to adjacent normal tissues. And then, we found there is a negative relationship between the expression of miR-205 and PTEN mRNA in lung cancer by analyzed. To validate whether PTEN was direct targets of miR-205, a dual-luciferase reporter assay was employed, the result showed that PTEN is a target gene of MiR-205. In subsequent experiments, we examined the expressions of PTEN protein and mRNA after transfection of miR-205 mimics or inhibitor into A549 cells, and A549 cell proliferation was measured by CCK-8 tests. We found that the expression of PTEN protein and mRNA in A549 cells were significantly down-regulated or up-regulated after miR-205 mimics and miR-205 inhibitors transfected into, and miR-205 could inhibits A549 cells proliferation. These results indicate that miR-205 might inhibitor the proliferation of A549 cells by regulating the expression of PTEN.