Figure 5.

FA pathway deficient cells have a threshold of tolerance to DNA damage that might be sustained by the CHKREC. Co-treatment with the WIP1 inhibitor CCT007093 along with MMC reduces the number of cells in M phase (H3S10PH+) (A) and increases the numbers of c-PARP+ cells (a marker of apoptosis) in the VU817 cell line (B), thus indicating that failing to reach the CCP-DDA attractor drives the cells toward cell cycle arrest or activation of cell death mechanisms. (C) Representative FACS plots showing how the mitotic index of the VU817 cell line is reduced by WIP1 inhibition with CCT007093. (D) Co-treatment of FA cells with CCT007093 does not modify the number of CA observed in MMC-treated FA-A cells. (E) Upon MMC treatment the VU817 FA-A cell line simultaneously over-expresses the genes codifying for WIP1 (PPM1D) and for p21 (CDKN1A). (F) Inhibition of WIP1 with CCT007093 in MMC treated cells changes the expression pattern toward apoptotic genes, such as APAF1, and definitive arrest genes, such as CDKN2A, which codifies for p16.