Figure 7. RT and MB cells exposed to the PLK4 inhibitor CFI-400945 underwent an irreversible state of cell cycle arrest - senescence.

(A) Beta galactosidase assay showed significant increase of senescent cells at 48 hours of CFI-400945 exposure (100nM) in all cell lines (MON, G401, BT-12, BT-16, DAOY and D283). (B) Clonogenic recovery assay: cells were incubated for 6 days with 100nM of CFI-400945, washed and exposed to 0.1% DMSO for an additional 12 days allowing for recovery. Control cells were incubated with 0.1% DMSO for 18 days or CFI-400945 100nM for 18 days. After 6 days of exposure to the drug, none of the cell lines recovered their ability to generate colonies further substantiating irreversibility of proliferation arrest.