Long non-coding RNA HOTAIR regulates cyclin J via inhibition of microRNA-205 expression in bladder cancer

The level of microRNA-205 (miR-205) is commonly deregulated in a number of cancers. Through the screening of the microRNA expression profile in bladder cancer tissue and cell lines, we found that expression of miR-205 was significantly suppressed. In addition, the levels of miR-205 expression had a negative correlation with the degree of bladder cancer malignancy. However, the biological functions of miR-205 remained unclear. In this study, we have demonstrated that miR-205 had a role in the inhibition of proliferation, migration and invasion of bladder cancer cells. Moreover, we have identified cyclin J (CCNJ) gene, which is involved in cell cycle regulation, as a novel target for miR-205. Furthermore, a long non-coding RNA HOTAIR (HOX transcript antisense RNA) was observed to participate in the silencing of miR-205 in bladder cancer cells by breaking the balance of histone modification between H3K4me3 (histone H3 at lysine 4 methylation) and H3K27me3 on miR-205 promoter. This study elucidates an important role that miR-205 had in the regulation of proliferation, migration and invasion of bladder cancer cells, suggesting a potential therapeutic target for combating bladder cancer.