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Adenovirus-mediated gene therapy for bladder cancer in an orthotopic model using a dominant negative H-ras mutant
T Watanabe1, N Shinohara, A Sazawa
1Department of Veterinary Clinical Sciences, Graduate School of Veterinary Medicine, Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan.
Abstract:
It has been suggested that abnormal Ras function is important in the carcinogenesis and progression of bladder cancer. Our aim was to investigate the efficacy of transurethral inoculation of an adenovirus expressing the dominant negative H-ras mutant N116Y against orthotopically implanted human bladder-cancer cells in nude mice. We used a replication-defective adenovirus vector containing the beta-galactosidase gene (AdCMV-LacZ) as a control and the N116Y gene (AdCMV-N116Y) as the therapeutic vector under the transcriptional control of the cytomegalovirus promoter. We initially investigated the in vitro growth-suppressive effects of AdCMV-N116Y on 2 human bladder-cancer cell lines, KU-7 and UMUC-2. Thereafter, we examined the inhibitory effects of AdCMV-N116Y on the 2 orthotopically implanted cell lines in nude mice. Intravesically created, orthotopic human bladder cancers were established in female KSN athymic nude mice with 1x 10(7) cancer cells. Then, 2, 3 and 4 days following implantation, 1 x 10(9) pfu of AdCMV-LacZ or AdCMV-N116Y were administered transurethrally. In vitro growth assays revealed significant growth suppression (>95%) with apoptosis of target cells treated with AdCMV-N116Y compared to AdCMV-LacZ. Transurethral inoculation of AdCMV-N116Y into the bladder brought about a significant reduction in size (73% to 90%) and number (47% to 78%) of orthotopically implanted human bladder tumors compared to AdCMV-LacZ or PBS. Normal mucosa in nude mice had minor inflammation with the infiltration of mononuclear cells. Our results suggest that gene therapy via transurethral inoculation of AdCMV-N116Y holds promise for the treatment of human bladder cancer.
Insights
Gene therapy using adenovirus (AdCMV-N116Y) shows promise for treating bladder cancer by suppressing tumor growth and inducing apoptosis in preclinical models.
Area of Science:
- Oncology
- Gene Therapy
- Molecular Biology
Background:
- Abnormal Ras function is implicated in bladder cancer development and progression.
- Targeting Ras signaling pathways offers a potential therapeutic strategy for bladder cancer.
Purpose of the Study:
- To evaluate the efficacy of transurethral delivery of an adenovirus expressing a dominant-negative H-ras mutant (AdCMV-N116Y) against human bladder cancer xenografts in nude mice.
- To assess the in vitro and in vivo anti-cancer effects of AdCMV-N116Y.
Main Methods:
- In vitro studies using human bladder cancer cell lines (KU-7, UMUC-2) treated with AdCMV-N116Y or control adenovirus (AdCMV-LacZ).
- In vivo studies involving orthotopic implantation of bladder cancer cells in nude mice, followed by transurethral administration of AdCMV-N116Y or AdCMV-LacZ.
- Tumor growth inhibition, apoptosis induction, and histological analysis were assessed.
Main Results:
- AdCMV-N116Y significantly suppressed in vitro bladder cancer cell growth (>95%) and induced apoptosis.
- Transurethral inoculation of AdCMV-N116Y resulted in substantial reductions in tumor size (73-90%) and number (47-78%) in vivo.
- Minimal inflammation was observed in the normal bladder mucosa of treated mice.
Conclusions:
- Transurethral gene therapy with AdCMV-N116Y demonstrates significant therapeutic potential for human bladder cancer.
- The dominant-negative H-ras mutant delivered via adenovirus is effective in inhibiting bladder tumor growth and progression.