Targeted gene therapy for canine osteosarcoma: preliminary investigations

RC0254 Neoplasms. Tumors. Oncology (including Cancer);RB Pathology

Sabine, Victoria Saranne ; Argyle, David J.

University:University of Glasgow

Department:School of Veterinary Medicine

关键词: canine osteosarcoma, TP53, gene therapy, CB1954, nitrofurazone, suicide gene, prodrug, nitroreductase, luciferase;   

Others  :  http://theses.gla.ac.uk/1642/1/2009sabinephd.pdf

来源: University of Glasgow

【 摘 要 】

Osteosarcoma (OS) is the most common bone cancer in dogs. It is biologically aggressive and <20% survive >2 years with standard therapy. Hence, new approaches must be considered. TP53 is altered in ~50% of human and canine cancers, including OS, making it a candidate for targeted suicide gene therapy strategies. Canine OS is considered to be a good model for human OS. The aims of this study were to: examine the site incidence of canine OS retrieved from Glasgow University Veterinary School (GUVS) histology database; perform TP53 mutational analysis in canine OS cases diagnosed at GUVS; investigate delivery of exogenous wild-type canine TP53 into D17, CMT3, CMT7 and CMT8 canine OS cell lines; design and construct vectors for a TP53-targeted suicide gene strategy, which can selectively target canine OS cells containing accumulated TP53, and initially analyse using Dual-Luciferase® reporter assays (DLR); perform suicide gene/prodrug assays using nitroreductase (NTR) in combination with CB1954 or nitrofurazone (NFZ) in several canine cell lines; replace luciferase with NTR in vectors for TP53-targeted suicide gene strategy, and with CB1954, determine if survival of CMT7 cells possessing accumulated TP53 are reduced, in comparison to D17 cells, containing wild-type TP53.OS were most commonly found in appendicular areas, followed by axial and extraskeletal sites; this agrees with published findings. No TP53 mutations were found in 7 biopsies removed from 4 dogs, 5 were OS, due to analysis of a small sample number, but still fits within published data. TP53 expression did not have a significant negative effect on canine OS cell growth. Contrasting results have been shown in canine and human OS cells. Luciferase expression levels following transfection with designed constructs were higher in CMT7 cells, than in D17 cells. Similar results were shown in NTR/CB1954 assays as reductions in cell survival only occurred in CMT7 cells but not in D17 cells. NFZ was not suitable as a prodrug for NTR in canine cells as there were no differences in cell survival with cells not expressing NTR. Hence, the TP53-targeted suicide gene therapy strategy appears to selectively reduce survival of canine OS cells possessing accumulated TP53, warranting further investigation as a treatment modality for OS, in both dogs and humans.