Adenovirus-mediated gene therapy for bladder cancer in an orthotopic modelusing a dominant negative H-ras mutant

It has been suggested that abnormal pas function is important in the carcin ogenesis and progression of bladder cancer, Our aim was to investigate the efficacy of transurethral inoculation of an adenovirus expressing the domin ant negative H-ras mutant N116Y against orthotopically implanted human blad der-cancer cells in nude mice. We used a replication-defective adenovirus v ector containing the beta -galoctosidase gene (AdCMV-LacZ) as a control and the N116Y gene (AdCMV-N116Y) as the therapeutic vector under the transcrip tional control of the cytomegalovirus promoter. We initially investigated t he in vitro growth-suppressive effects of AdCMV-N116Y on 2 human bladder-ca ncer cell lines, KU-7 and UMUC-2. Thereafter, we examined the inhibitory ef fects of AdCMV-N116Y on the 2 orthotopically implanted cell lines in nude m ice, Intravesically created, orthotopic human bladder cancers were establis hed in female KSN athymic nude mice with 1 x 10(7) cancer cells, Then, 2, 3 and 4 days following implantation, 1 x 10(9) pfu of AdCMV-LacZ or AdCMV-N1 16Y were administered transurethrally, In vitro growth assays revealed sign ificant growth suppression (>95%) with apoptosis of target cells treated wi th AdCMV-N116Y compared to AdCMV-LacZ, Transurethral inoculation of AdCMV-N 116Y into the bladder brought about a significant reduction in size (73% to 90%) and number (47% to 78%) of orthotopically implanted human bladder tum ors compared to AdCMVLacZ or PBS, Normal mucosa in nude mice had minor infl ammation with the infiltration of mononuclear cells. Our results suggest th at gene therapy via transurethral inoculation of AdCMV-N116Y holds promise for the treatment of human bladder cancer. (C) 2001 Wiley-Liss Inc.