This study provided the first glimpse of the functional role of miR-133 in bladder cancer T24 and EJ cells. The results may increase our knowledge on the molecular basis of progression and provide potential therapy for bladder cancer.

The expression of microRNA-125b (miR-125b) has been investigated in many human cancers. It has been demonstrated to be downregulated in certain types of cancer, such as bladder cancer, thyroid anaplastic carcinomas, squamous cell carcinoma of the tongue, hepatocellular carcinoma, ovarian and breast cancer. In the present study, we examined the effects of miR-125b on bladder cancer cell migration and invasion. Following transfection of miR-125b, the expression of miR-125b was analyzed in T24 and EJ bladder cancer cells. Additionally, cell migration, cell invasion and luciferase assays, as well as western blot analysis were conducted in the bladder cancer cells. In this study, we demonstrated that miR-125b inhibited cell migration and invasion in T24 and EJ cells. We also provided the first evidence that miR-125b may directly target matrix metalloproteinase 13 (MMP13) in bladder cancer. Our study provided evidence that miR-125b suppresses cell migration and invasion by targeting MMP13 in bladder cancer cell lines. These results suggested that miR-125b could be used for the development of new molecular markers and therapeutic approaches to inhibit bladder cancer metastasis.

Regulator of Cullins-1 (ROC1) is a key subunit in the Cullin-RING ligase (CRL) protein complex. Overexpression of ROC1 protein is associated with tumor progression and poor prognosis of non-muscle invasive bladder transitional cell carcinoma (NMIBC). This study was designed to assess the effects of ROC1 knockdown in bladder cancer cells and to determine the potential mechanisms involved. A total of 112 bladder cancer tissue specimens were recruited for immunohistochemical analyses of ROC1 overexpression. Bladder cancer cell lines were used to knockdown ROC1 expression using ROC1 siRNA. Our data showed that ROC1 knockdown remarkably inhibited bladder cancer cell growth, arrested cells at the G2 phase of the cell cycle, and induced the p53-dependent cell senescence. Molecularly, G2 arrest was associated with upregulation of p21, p27, cyclin B1, and Cdc2 proteins. ROC1 knockdown induced-senescence functioned through p53/p21 pathway. Knockdown of p21 expression partially rescued ROC1 knockdown-induced growth inhibition in cancer cells. Furthermore, nude mouse xenograft analyses confirmed these in vitro data. In conclusion, data from the current study indicate that ROC1 plays an essential role in bladder cancer progression and could serve as a novel anticancer target for bladder transitional cell carcinoma (BTCC).

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