Fig. 6.

WYC-209 inhibits TRCs growth by binding RA receptors and via the caspase 3 pathway. a Control B16-F1 cells were cultured in 90-Pa fibrin gels treated with RA receptor antagonists for 3 h, then treated with 0.1 or 1 μM WYC-209, and cultured for 5 days. Summarized colony sizes after drug treatments on day 5 were compared with DMSO groups. None: medium without drugs. DMSO: medium with 0.1% DMSO. BMS 195614: Retinoic acid receptor (RAR) α-selective antagonist. CD 2665: selective RARβ/γ antagonist. b Control B16-F1 cells were transfected with negative control (scrambled siRNA), RARα, RARβ, or RARγ siRNA #1 s, respectively, and were then re-plated in soft fibrin gels, and were treated with 0.1 or 1 μM WYC-209. Summarized colony sizes after drug treatments on day 5 were compared with Negative control groups. None: medium without drugs. DMSO: medium with 0.1% DMSO. Neg Ctr: negative control. c Control B16-F1 cells were cultured in 90-Pa fibrin gels treated with caspase 3 inhibitor Z-DEVD-FMK for 3 h, then treated with 0.1 or 1 μM WYC-209, and cultured for 5 days. Summarized colony sizes after drug treatments on day 5 were compared with DMSO groups. None: medium without drugs. DMSO: medium with 0.1% DMSO. Z-DEVD-FMK: caspase 3 inhibitor. d Control B16-F1 cells were transfected with negative control (scrambled siRNA), caspase 3 siRNA #1, #2, or #3, respectively. The cells were then re-plated in soft fibrin gels and treated with 0.1 or 1 μM WYC-209. Summarized colony sizes after drug treatment on day 5 were compared with Negative control groups. DMSO: medium with 0.1% DMSO. Neg Ctr: negative control. Mean ± s.e.m.; n = 15 samples; three separate experiments; ^*P < 0.05; ^**P < 0.01; ^***P < 0.001. Student’s t-test (plus Bonferroni correction when appropriate) was used for statistics