IN-VITRO INVESTIGATIONS OF NEW THERAPEUTIC AGENTS ON BLADDER-TUMOR CELL-LINES

In this study sensitivity of human transitional cancer cells to the an ticancer agent paclitaxel, an antimicrotubular drug, and to gallium ni trate, a group IIIa metal, was compared to that of the standard MVAC ( methotrexate, vinblastine, doxorubicin and cisplatin) drugs. The reduc tion of cell proliferation was evaluated after 48 h of incubation of s ix different cell lines with each agent using the mean transit time (M TT) assay. We investigated both monolayers and spheroids. Paclitaxel s howed significantly higher growth inhibitory effects on monolayers tha n vinblastine, both agents targeting the antimicrotubular apparatus. T his could not be reproduced on spheroids, where a survival fraction of 50% was observed even at high concentrations (10 mu M). High concentr ations of gallium nitrate were needed to achieve sufficient toxicity. These concentrations are beyond the concentration achievable by system ic application. Our findings suggest that paclitaxel may be a clinical ly useful agent for systemic and intravesical use in bladder cancer.