A novel immunotherapy for superficial bladder cancer by the immobilization of streptavidin-tagged bioactive IL-2 on the biotinylated mucosal surface of the bladder wall
Xin Huang, Hong-sheng Yu , Zhong Chen , Jin-Long Li, Zhi-Ming Hu, Ji-Min Gao
Institute of Biotherapy, School of Biotechnology, Southern Medical University, Guangzhou, Guangdong 510515, P. R. China. hzhiming99@127.com
[Abstract] Background and Objective: Intravesical administration of Bacillus Calmette-Guèrin (BCG) after transurethral resection is by far the most effective local therapy for superficial bladder cancer, the fifth most common cancer in the world. However, approximately one-third of patients fail to respond and most patients eventually relapse. In addition, there are pronounced side effects of BCG therapy, such as BCG sepsis and a high frequency of BCG-induced cystitis. This study established a novel immunotherapy through immobilization of streptavidin-tagged human IL-2 (SA-hIL-2) on the biotinylated mucosal surface of bladder wall. Methods: A mouse orthotopic model of MB49 bladder cancer was established by perfusing MB49 cells into mouse bladders. The SA-hIL-2 fusion protein was immobilized on the biotinylated mucosal surface of the bladder wall. Treatment began on day 1 after MB49 implantation, once every 3 days for 6 times. Immunohistochemical assay was performed to assess the persistence of SA-hIL-2 immobilized on the biotinylated mucosal surface of the bladder wall. The mice were monitored for tumor growth and survival. On day 60 after MB49 implantation, the SA-hIL-2-cured mice, which were found to have no hematuria or palpable tumors, were challenged with wild-type MB49 cells implanted into the pretreated bladder and monitored for survival. Results: SA-hIL-2 could be immobilized efficiently and durably on the bladder mucosal surface as long as 7 days. On day 60 after MB49 implantation, 9 out of 20 SA-hIL-2-treated mice survived, but all mice in PBS control group died. More importantly, 5 out of 9 tumor-free mice in the SA-hIL-2 group were protected against a second intravesical wild-type MB49 tumor challenge. Conclusions: SA-hIL-2 fusion protein could significantly inhibit tumor growth and extend the survival time in the orthotopic model of MB49 bladder cancer.
Chinese Journal of Cancer 2010, Volume: 29, Issue 6, Page: 611-616
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