Gene therapy for bladder cancer using adenoviral vector.

BACKGROUND AND PURPOSE Bladder cancer is common. Current treatment for patients with superficial bladder cancer involves transurethral resection followed by adjuvant bacillus Calmette-Guérin (BCG) administration. Adjuvant BCG has been reported to be effective in 38% to 68% of patients; however, more than 30% of patients do not respond. Because p53 mutations are common among superficial bladder cancers, we tested the feasibility of using p53 as a gene therapy agent for targeting superficial tumors, which are easily accessible using an intravesical approach. MATERIALS AND METHODS Wild-type p53 was transduced into various human and murine bladder cancer cell lines (HTB9, KU-1, and MBT-2) using a recombinant adenoviral vector (Ad5CMV-p53) in vitro. Also, subcutaneous tumors were established and then treated with intratumoral injection of Ad5CMV-p53 or control viruses. RESULTS In vitro assays revealed significant growth suppression of target cells by Ad5CMV-p53 in comparison with those receiving the control Ad5-CMV-PA vector or untreated control cells. In vivo studies using subcutaneous bladder tumor models established in syngeneic mice demonstrated that the rate of tumor growth and volume was reduced to a greater extent by 14 days of intratumoral injection of Ad5CMV-p53 rather than Ad5CMV-PA. Furthermore, the survival of host animals bearing tumors that were infected with Ad5CMV-p53 was significantly longer than that of the control group treated with Ad5CMV-PA (P < 0.01). CONCLUSION Our data suggest that Ad5CMV-p53 is effective in suppressing bladder cancer growth and improving host survival.