(A) Sensitivity of agents within the Prestwick chemical library is defined as individual dots. The sensitivity in the presence (red) or absence (blue) of CDK4/6 inhibitor palbociclib (PD) is plotted. Select agents, for which pretreatment with CDK4/6 inhibitor antagonized initial cytotoxicity (robust Z score less than −3.0), are shown in the table. The score shown is the percent effect on viability, where −100 represents complete loss of viability.
(B) Dose response of cells treated with the indicated agents, either alone (black bars) or with prior treatment with a CDK4/6 inhibitor (gray bars). The mean and SD are shown (***p < 0.001, as determined by t test).
(C) Flow cytometry showing the DNA-content of either MB231 cells or S2 cells treated with colchicine, palbociclib (PD), or pretreated with palbociclib and then treated with colchicine. Representative histograms are shown.
(D) Dose response of cells treated with the indicated agents, either alone (black bars) or with prior treatment with a CDK4/6 inhibitor (gray bars). The mean and SD are shown (***p < 0.001, as determined by t test).
(E) MB231 and MB468 cells were treated with the indicated agents at increasing dose. The mean and SD are shown (***p < 0.001, as determined by t test).