876 LOW DOSE METHOTREXATE ENHANCES CYTOTOXICITY OF GEMCITABINE AGAINST CISPLATIN-RESISTANT UROTHELIAL CANCER CELLS

Abstract

You have accessJournal of UrologyBladder Cancer: Basic Research1 Apr 2011876 LOW DOSE METHOTREXATE ENHANCES CYTOTOXICITY OF GEMCITABINE AGAINST CISPLATIN-RESISTANT UROTHELIAL CANCER CELLS Masaaki Tachibana, Yoshio Ohno, Ayako Tanaka, Kenji Shimodaira, Jun Nakashima, Makoto Ohori, and Tadashi Hatano Masaaki TachibanaMasaaki Tachibana Tokyo, Japan More articles by this author , Yoshio OhnoYoshio Ohno Tokyo, Japan More articles by this author , Ayako TanakaAyako Tanaka Tokyo, Japan More articles by this author , Kenji ShimodairaKenji Shimodaira Tokyo, Japan More articles by this author , Jun NakashimaJun Nakashima Tokyo, Japan More articles by this author , Makoto OhoriMakoto Ohori Tokyo, Japan More articles by this author , and Tadashi HatanoTadashi Hatano Tokyo, Japan More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2011.02.700AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Cisplatin, the taxans, and gemcitabine are main chemotherapeutic agent for urothelial cancer. Although combinations of these agents have shown clinical benefit in advanced urothelial cancer, most of patients finally develop recurrent disease. The alternative regimens including cisplatin/paclitaxel, gemcitabine/paclitaxel, and gemcitabine/docetaxel have also shown modest activity. Therefore, development of new combination chemotherapy is needed. This study was undertaken to evaluate the efficacy of combination of gemcitabine and methotrexate in cisplatin-resistant urothelial cancer cells. METHODS Three human bladder cancer cell lines (KU-1, KU-7, KU19-19) were used. Cisplatin-resistant sub-lines were established by repeated subcultures in the presence of increasing concentrations of cisplatin. The cells were exposed to gemcitabine (50 nM, 500 nM) and methotrexate (1μM, 10μM) as single agents and to various combinations (simultaneous exposure, preincubation with methotrexate followed by gemcitabine exposure, preincubation with gemcitabine followed by methotrexate exposure). The concentrations in the combination exposure had the same range as the separate agents. The cytotoxic effects were examined by fluorometric assay. Furthermore, flow cytometric DNA/bromodeoxyuridine measurement was used to evaluate the effect on cell cycle. RESULTS The fluorometric assay showed that growth inhibitory effect of cisplatin was decreased by 2.5-fold in cisplatin-resistant sublines compared to parental cell lines. Cell cycle analysis demonstrated that exposure of methotrexate synchronized both parental and cisplatin-resistant cells to S-phase. After a 48h exposure, maximal growth inhibition was observed in cells exposed to 1μM of methotrexate and 50nM of gemcitabine simultaneously, or in cells pre-incubated with 1μM of methotrexate followed by 50nM of gemcitabine exposure. This effect was higher than that of simultaneous exposure of 10 μM of methotrexate and 500 nM of gemcitabine in all three parental cell lines and corresponding cisplatin-resistant sublines. CONCLUSIONS The combination of methotrexate and gemcitabine demonstrated enhanced growth inhibition on urothelial cancer cells: this inhibition was obtained without increasing the concentration of each agent. This in vitro results support the possible combination of low-dose gemcitabine and methotrexate in the treatment of urothelial cancer patients. © 2011 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 185Issue 4SApril 2011Page: e350-e351 Advertisement Copyright & Permissions© 2011 by American Urological Association Education and Research, Inc.MetricsAuthor Information Masaaki Tachibana Tokyo, Japan More articles by this author Yoshio Ohno Tokyo, Japan More articles by this author Ayako Tanaka Tokyo, Japan More articles by this author Kenji Shimodaira Tokyo, Japan More articles by this author Jun Nakashima Tokyo, Japan More articles by this author Makoto Ohori Tokyo, Japan More articles by this author Tadashi Hatano Tokyo, Japan More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...