Dual role of TGFBR3 in bladder cancer

Bladder cancer is one of the most common genitourinary malignant diseases worldwide. More than 90% of bladder cancer cases are bladder urothelial carcinoma (BUC). Although transforming growth factor-β III receptor (TGFBR3) has been suggested to play a dual role in cancer progression, little is known about TGFBR3 in bladder cancer. In the present study, fresh tumor and the corresponding paracarcinoma tissue specimens were collected from 56 bladder urothelial carcinoma patients. TGFBR3 expression in these tissues was determined by western blotting. TGFBR3 was also detected in the human normal urothelial cell line SV-HUC-1, the human superficial urothelial bladder cancer cell line 5637, and the human invasive bladder cancer cell line T24 using western blotting and quantitative PCR. Cell growth, motility and invasion were also analyzed in the control and the TGFBR3 gene-silenced T24 cells. As a result, the expression of TGFBR3 was reduced (18/30) in most superficial bladder urothelial carcinoma tissues compared to the corresponding normal tissues, whereas TGFBR3 expression was more enhanced (19/26) in the invasive samples. Similarly, an increase of TGFBR3 expression was found in T24 cells, but a decrease was observed in 5637 cells. Knockdown of TGFBR3 in T24 cells resulted in decreased cell growth, motility and invasion. In conclusion, these findings suggest that TGFBR3 may play a dichotomous role in human bladder cancer, acting as both a tumor suppressor and as a tumor promoter.