Introduction

Cytochrome P450 1B1 (CYP1B1) has been shown to be up-regulated in many types of cancer including renal cell carcinoma (RCC), while several reports have shown that CYP1B1 influences regulation of tumor development. However, its role in RCC development has not been elucidated. Here, we explored the functional role and regulatory mechanism of CYP1B1 in RCC.

Methods

CYP1B1 expression was determined in RCC cell lines, and microarray findings of 96 RCC and 25 normal tissues were obtained. To examine the biological significance of CYP1B1 in RCC progression, we silenced the gene in Caki-1 and 769-P cells by RNA interference, and performed various functional analyses. Furthermore, we evaluated whether miR-200c expression, significantly down-regulated in RCC, is associated with CYP1B1 level in both clinical samples and cell lines.

Results

First, we confirmed that CYP1B1 protein expression was significantly higher in RCC cell lines as compared to normal kidney tissues, a trend that was also observed in RCC tumor samples (p<0.01). Furthermore, CYP1B1 expression was associated with tumor grade and stage. Next, we silenced the gene in Caki-1 and 769-P cells by RNA interference, and performed various functional analyses to determine the biological significance of CYP1B1 in RCC progression. Inhibition of CYP1B1 expression resulted in decreased cell proliferation, and migration and invasion of RCC cells, while that also induced apoptosis of Caki-1 cells. In addition, gene microarray findings indicated that the anti-tumor effects on RCC cells caused by CYP1B1 depletion might have been due to alteration of CDC20 and DAPK1 expressions, which was confirmed by real-time PCR. Interestingly, CYP1B1 expression was associated with CDC20 and DAPK1 expressions in the clinical samples. Finally, we found that CYP1B1 level was inversely correlated with miR-200c expression in RCC, and miR-200c directly targets the CYP1B1 3&[prime]-UTR and regulates its expression.

Conclusions

CYP1B1 up-regulation mediated by reduced expression of miR-200C may promote RCC development by inducing CDC20 expression and inhibiting apoptosis via down-regulation of DAPK1. Our results demonstrate that CYP1B1 and miR-200c are potential tumor biomarkers and targets for anticancer therapy in RCC patients.

Funding

none