c-Met inhibitors repressed cell growth and c-Met receptor phosphorylation in PC-3 and DU-145 prostate cancer cells. (A) PC-3 cells were cultured with DMEM supplemented with 5% FBS. The c-Met inhibitor, PHA-665752 or PF-2341066, dissolved in DMSO was added to the growth media at the indicated concentration. Cells were harvested and analyzed by the MTS assay at indicated time-points. Absorbance at 490 nm was measured in triplicate samples. The data represent the mean ± S.D. of three independent experiments. (B) The similar MTS assays were carried out in DU-145 cells. (C) Approximately 50 PC-3 or DU-145 cells per well were plated in quadruplicate in 6-well plates for 24 hr, and then PHA-665752 or PF-2341066 was added to cells. Cells were allowed to grow for 10 days then fixed and stained with crystal violet. (D) PC-3 or DU-145 cells were cultured with 5% FBS-DMEM and were then exposed for 3 hours to DMSO alone, 0.5 μM of PHA-665752, or 0.5 μM of PF-2341066 dissolved in DMSO. Whole cell lysates were prepared from the above cells for immunoblotting with c-Met or phosphorylated c-Met antibody, as well as the β-tubulin antibody as a loading control.