Identification of [1,2,4]Triazolo[4,3-a]pyrazine PARP1 inhibitors with overcome acquired resistance activities

Eur J Med Chem. 2023 Nov 5:259:115709. doi: 10.1016/j.ejmech.2023.115709. Epub 2023 Aug 4.

Abstract

Poly(ADP-ribose) polymerase 1 (PARP1) inhibitors can selectively kill homologous recombination (HR) deficient cancer cells and elicit anticancer effect through a mechanism of synthetic lethality. In this study, we designed, synthesized and pharmacologically evaluated a series of [1,2,4]triazolo[4,3-a]pyrazine derivatives as a class of potent PARP1 inhibitors. Among them, compounds 17m, 19a, 19c, 19e, 19i and 19k not only displayed more potent inhibitory activities (IC50s < 4.1 nM) than 9 and 1 against PARP1, but also exhibited nanomolar range of antiproliferative effects against MDA-MB-436 (BRCA1-/-, IC50s < 1.9 nM) and Capan-1 (BRCA2-/-, IC50s < 21.6 nM) cells. Notably, 19k significantly inhibited proliferation of resistant Capan-1 cells (IC50s < 0.3 nM). Collectively, the newly discovered PARP1 inhibitors act as a useful pharmacological tool for investigating the mechanism of acquired resistance to PARP1 inhibitors, and may also represent promising therapeutic agents for the treatment of HR deficient cancers with the potential to overcome the acquired resistance.

Keywords: Anticancer; Drug resistance; PARP1 inhibitor; Structure−activity relationship; Synthetic lethality.

MeSH terms

  • Cell Line, Tumor
  • Homologous Recombination
  • Humans
  • Neoplasms* / drug therapy
  • Poly (ADP-Ribose) Polymerase-1
  • Poly(ADP-ribose) Polymerase Inhibitors* / pharmacology
  • Poly(ADP-ribose) Polymerase Inhibitors* / therapeutic use

Substances

  • Poly(ADP-ribose) Polymerase Inhibitors
  • Poly (ADP-Ribose) Polymerase-1
  • PARP1 protein, human