Selective cytotoxicity of gemcitabine in bladder cancer cell lines

We have examined the cytotoxic effect of gemcitabine in intravesical therapy using an in vitro co-cultured spheroid model composed of transitional cell carcinoma (TCC) and fibroblasts from both human and rat species. Immunohistochemistry analysis of the co-cultured spheroids, using cytokeratin-13 and vimentin antibodies against TCC and fibroblasts, respectively, showed the central location of fibroblasts within the spheroid, whereas TCC formed the peripheral layers. Spheroids composed of humanTCC and fibroblasts (MGH-U3/CRL-1120 or RT-112/CRL-1120) as well as rat TCC and their corresponding fibroblasts (AY-27/RF-Ed1) displayed the same drug tolerance profile after an exposure of 0,1, 3, 5, 7 and 14 days. As confirmed by time-lapse photography, MTT essay and vital dye staining, gemcitabine selectively killed the human and rat bladder cancer cell lines, but did not affect un-transformed human and rat fibroblast lines. [(C) 2002 Lippincott Williams Wilkins].