PF-477736 (128 nM) abrogates the camptothecin-induced DNA damage checkpoint in a dose-dependent manner in CA46 and HeLa cells. PF-477736 effectively abrogates the gemcitabine-induced S-phase arrest with a corresponding increase in apoptotic cell populations in HT29 cells. PF-477736 (540 nM) enhances gemcitabine-induced cytotoxicity in a time- and dose-dependent manner in HT29 cells. PF-477736 potentiates the growth-inhibitory activity of a panel of chemotherapeutic agents across a broad spectrum of p53-deficient human cancer cell lines in the MTT assay. Addition of PF-477736 (360 nM) to gemcitabine-arrested cells induces a dramatic increase in the intensity of H2AX phosphorylation, reflecting a greater number of γ-H2AX molecules near sites of DNA damage. PF-477736 (0.5 nM) selectively blocks p73 and P53 phosphorylation in presence of curcumin in HL-60 cells. PF-477736 (360 nM) suppresses docetaxel-induced phosphorylation of histone H3 (Ser10) and Cdc25C (Ser216) and potentiates apoptosis in COLO205 cells. PF-477736 (250 nM) combined with MK-1775 has marked synergistic cytotoxic activity in OVCAR-5 cells. PF-477736 (250 nM) combined with MK-1775 causes accumulation of cells with a DNA content between 2N and 4N in OVCAR-5 cells. PF-477736 (250 nM) combined with MK-1775 causes premature mitosis before the end of DNA replication, with damaged DNA leading to apoptotic cell death in OVCAR-5 cells.
体内研究:PF-477736 (4 mg/kg i.v.) results in terminal half-life (T1/2) of 2.9 hours, AUC of 5.72 μg×hr/mL and CLp of 11.8 mL/min/kg in rats. PF-477736 dose-dependently enhances the antitumor activity of a maximum tolerated dose of gemcitabine in the Colo205 xenograft mouse model. PF-477736 (12 mg/kg) induces an increase in the phosphorylation of histone H3 (Ser10) and of phospho-histone H2AX in the Colo205 xenograft mouse model. PF-477736 (15 mg/kg i.p.) enhances docetaxel induced tumor growth inhibition and tumor growth delay in COLO205 and MDA-MB-231 xenograft models. PF 477736 (10 mg/kg once daily i.p.) combined with MK-1775 (30 mg/kg twice a day oral) leads to greater tumor growth inhibition in mice bearing OVCAR-5 xenografts.