977 THIOTHYMIDINE COMBINED WITH UVA AS A POTENTIAL NOVEL THERAPY FOR BLADDER CANCER

Abstract

You have accessJournal of UrologyBladder Cancer: Basic Research II1 Apr 2010977 THIOTHYMIDINE COMBINED WITH UVA AS A POTENTIAL NOVEL THERAPY FOR BLADDER CANCER Simon Pridgeon, Gordon Taylor, Keiran O'Toole, Mary Robinson, and Alan Boddy Simon PridgeonSimon Pridgeon London, United Kingdom More articles by this author , Gordon TaylorGordon Taylor Newcastle upon Tyne, United Kingdom More articles by this author , Keiran O'TooleKeiran O'Toole Newcastle upon Tyne, United Kingdom More articles by this author , Mary RobinsonMary Robinson Newcastle upon Tyne, United Kingdom More articles by this author , and Alan BoddyAlan Boddy Newcastle upon Tyne, United Kingdom More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2010.02.1924AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Thiothymidine (TT) is a thymidine analogue which is readily incorporated into cellular DNA. TT is sensitive to UVA (336nm) and on exposure undergoes photochemichal reactions. It is hypothesised that TT incorporated into bladder tumors and subsequently exposed to UVA will form cytotoxic DNA lesions. METHODS MYU-3L and AY27 bladder cancer cell lines were cultured with TT and exposed to UVA. Cytotoxicity was assessed using the SRB assay. Following DNA extraction and digestion, TT incorporation was measured using LC/MS. DNA lesions were characterised using the COMET assay. Bladder tumours were established in Fischer rats by intravesical instillation of tumor cells. TT incorporation into tumor DNA following intravesical or intravenous administration was measured using LC/MS. In vivo efficacy was studied in 5 animals treated with TT and UVA delivery using a 0.4 mm fiber optic. TT uptake into human bladder tumours was studied in an ex-vivo setting. RESULTS TT was measured in DNA of bladder cancer cells replacing 0.1-0.6% thymidine. 100% growth inhibition was observed when AY27 cell lines were incubated with 2uM TT and exposure to 2.5 KJ/m2 UVA. For MYU-3L cells, 100% growth inhibition was observed following incubation with 20 uM TT and exposure to 10 KJ/m2 UVA. Following treatment with TT and UVA, the COMET assay demonstrated the formation of bulky DNA adducts with >50% reduction in Olive tail moments. ProteinaseK treatment suggested these DNA lesions were both DNA-DNA adducts and DNA-protein crosslinks. TT and UVA treatment was associated with an 8-fold increase in caspase 3/7 activity and positive annexin binding suggesting apoptosis. Bladder tumours were successfully established in Fischer rats using MYU-3L cells. TT incorporation was detectable follwing both intravesical and intravenous TT administration. TT replaced 0.0035% of thymidine residues following a 2 hour intravesical TT instillation (16mg) and 0.2 % thymidine replacement was measure following IV TT injection (32 mg). Treatment responses were observed in 60% rats following intravenous TT and intravesical UVA (5 KJ/m2) delivery. TT was detected in 30/40 human bladder tumor resection specimens following 24 hour ex-vivo incubation replacing 0.03 % thymidine. CONCLUSIONS TT has been shown to be incorporated into bladder cancer cell lines. The subsequent exposure to low doses of UVA results in growth inhibition due to the formation of DNA crosslinks. These crosslinks are associated with apoptosis. In vivo and ex vivo treatment suggest that the combination of TT and UVA may offer a novel selective local treatment for bladder cancer © 2010 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 183Issue 4SApril 2010Page: e380 Advertisement Copyright & Permissions© 2010 by American Urological Association Education and Research, Inc.MetricsAuthor Information Simon Pridgeon London, United Kingdom More articles by this author Gordon Taylor Newcastle upon Tyne, United Kingdom More articles by this author Keiran O'Toole Newcastle upon Tyne, United Kingdom More articles by this author Mary Robinson Newcastle upon Tyne, United Kingdom More articles by this author Alan Boddy Newcastle upon Tyne, United Kingdom More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...