Design, Synthesis, and In Vitro Evaluation of the Photoactivatable Prodrug of the PARP Inhibitor Talazoparib

Abstract

In this article, we report the design, synthesis, photodynamic properties, and in vitro evaluation of photoactivatable prodrug for the poly (ADP-ribose) polymerase 1 (PARP-1) inhibitor Talazoparib. In order to yield a photoactivatable, inactive prodrug, photoactivatable protecting groups (PPGs) were employed to mask the key pharmacophore of Talazoparib. Our study confirmed the good stability and photolytic effect of prodrugs. A PARP-1 enzyme inhibition assay and PARylation experiment showed that the inhibitory activity of the prodrug was reduced 380 times and more than 658 times, respectively, which proved that the prodrug’s expected activity was lost after PPG protection. In BRCA1- and BRCA2-deficient cell lines, the inhibitory activity of the compound was significantly restored after ultraviolet (UV) irradiation. The results indicate that the photoactivatable prodrug strategy is an interesting approach for studying PARP inhibitors. Meanwhile, the described photoactivatable prodrug also provided a new biological tool for the mechanism research of PARP.

Keywords

• talazoparib
• parp inhibitor
• prodrug
• o-nitro-benzyl
• photoactivatable protecting groups