Knockdown of THBS1 sensitizes cells to CB-5083 and promotes apoptosis. (A) HCT116 cells transfected with siControl or siTHBS1-1 (shortly siTHBS1) were treated with or without 0.75 μM CB-5083 for 8 h. Total extracts were analyzed by immunoblotting. Actin was used as a loading control. (B) HCT116 cells transfected with siControl or siTHBS1 were treated with or without 0.375 μM CB-5083 for 72 h. Cells stained with crystal violet and are shown. (N = 3, SD error). *p < 0.05. (C) HCT116 cells transfected with siControl or siTHBS1 were treated with or without 0.375 μM CB-5083. Cell numbers were counted at 24 h intervals (N = 3, SD error). *p < 0.05. (D) HCT116 cells transfected with siControl or siTHBS1 were treated with indicated concentrations of CB-5083. Cell viability was analyzed by quantifying cellular ATP levels (N = 3, SD error). *p < 0.05. (E) HCT116 cells transfected with siControl or siTHBS1 were treated with indicated concentrations of CB-5083 for 72 h. Cell cycle was analyzed by flow cytometry and the percent Sub-G1 is shown (N = 3, SD error). *p < 0.05. (F) HCT116 cells transfected with siControl or siTHBS1 were treated with indicated concentrations of CB-5083 for 72 h. Caspase 3/7 activities were measured by immunofluorescence (N = 3, SD error). *p < 0.05.