Effect of VFL on cytotoxicity of bladder tumour cell lines. The five indicated human tumour bladder cell lines (HT1376, 5637, SW780 in upper panel; UMUC3 and T24 in bottom panel) were treated with increasing concentrations of VFL (0–100 μM) for 48 h. Cell viability was determined by the MTT assay. A, HT1376. B, 5637. C, SW780. D, UMUC3 E, T24. Data are the means ± SEM of three independent experiments represented by logarithmic scale, and the IC50 value and CI95% for each cell line are indicated.