Role of VEGF in the growth and metastasis of a murine bladder carcinoma

Bladder transitional cell carcinoma is the most common form of carcinoma in the urinary system. Although overexpression of VEGF has been identified in tissue, serum, and urine of patients with bladder cancer, the role of VEGF in transitional cell carcinoma of the bladder has not been clearly elucidated. Here, we dissected the effect of VEGF during bladder tumor growth and progression by modifying a BBN (N-butyl-N-(4-hydroxybutyl) nitrosamine) induced mouse bladder transitional cell carcinoma cell line BTT-T739 by stable transfection of antisense VEGF 121 cDNA. The transfection resulted in more than 80% reduction in VEGF production. The growth of the transduced tumor cells in vitro was not affected, however, these cells formed small or no tumors in vivo. Even in the tumors formed, there were minimal vascularization, extensive necrosis and longer latency compared to those formed by parental cells. The permeability of tumor vasculature and metastatic tumor growth were also significantly suppressed in antisense VEGF cDNA transfected cells. In addition, the transfer of anti-angiogenic gene in a combination of sFlk-1 and ExTek with electroporation can suppress the tumor growth efficiently. Taken together, these results demonstrated that VEGF plays an important role in bladder tumor angiogenesis and angiogenesis plays an important role in bladder tumor growth and metastasis.