Effect of YC-1-induced cytotoxicity in human renal cancer A498 cells. Cells were incubated in the absence (control; CTL) or presence of YC-1, in serum-containing medium for 24 h (MTT assay) or 48 h (SRB assay). The cytotoxic effect (a) was determined using the MTT assay and the antiproliferative effect (b) was determined using the SRB assay. (c) The cell cycle progression and cell apoptosis were determined using FACScan analysis as described in Materials and methods section. (d) Fluorescence microscopic examination of untreated or YC-1 treated at the indicated concentrations for 24 h followed by DAPI staining. YC-1 significantly induced chromatin condensation and nuclei fragmentation. Magnification × 40. *P<0.05, **P<0.01 and ***P<0.001 compared with the control group. DAPI, 4′-6-diamidino-2-phenylindole; MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; SRB, sulphorhodamine B.