| In Vitro | In vitro activity: Rucaparib is a potent inhibitor of purified full-length human PARP-1 and shows higher inhibition of cellular PARP in LoVo and SW620 cells. Besides, Rucaparib binds detectably to eight other PARP domains, including PARP2, 3, 4, 10, 15, 16, TNKS1 and TNKS2. The radio-sensitization by Rucaparib is due to downstream inhibition of activation of NF-κB, and is independent of SSB repair inhibition. Rucaparib could target NF-κB activated by DNA damage and overcome toxicity observed with classical NF-κB inhibitors without compromising other vital inflammatory functions. Rucaparib inhibits PARP-1 activity by 97.1% at a concentration of 1 μM in permeabilised D283Med cells.
Kinase Assay: Inhibition of human full-length recombinant PARP-1 by [32P]NAD+ incorporation is measured. The [32P]ADP-ribose incorporated into acid insoluble material is quantified using a PhosphorImager. Ki is calculated by nonlinear regression analysis.
Cell Assay: In the MDCKII parental cell line, which overexpressed human (h) ABCB1, both apically and basolaterally directed translocation of rucaparib were the same. Treatment of the cells with the ABCB1 inhibitor zosuquidar resulted in a slight decrease in apically directed transport, which could be either due to a specific inhibition of an unidentified rucaparib uptake transporter at the basolateral side, or inhibition of endogenous canine ABCB1. The result shown that rucaparib is a transported substrate of ABCB1. |
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