Synthesis and Evaluation of a New Generation of Orally Efficacious Benzimidazole-Based poly(ADP-ribose) polymerase-1 (PARP-1) Inhibitors as Anticancer Agents

J Med Chem. 2009 Nov 12;52(21):6803-13. doi: 10.1021/jm900697r.

Abstract

Small molecule inhibitors of PARP-1 have been pursued by various organizations as potential therapeutic agents either capable of sensitizing cytotoxic treatments or acting as stand-alone agents to combat cancer. As one of the strategies to expand our portfolio of PARP-1 inhibitors, we pursued unsaturated heterocycles to replace the saturated cyclic amine derivatives appended to the benzimidazole core. Not only did a variety of these new generation compounds maintain high enzymatic potency, many of them also displayed robust cellular activity. For example, the enzymatic IC(50) and cellular EC(50) values were as low as 1 nM or below. Compounds 24 (EC(50) = 3.7 nM) and 44 (EC(50) = 7.8 nM), featuring an oxadiazole and a pyridine moiety, respectively, demonstrated balanced potency and PK profiles. In addition, these two molecules exhibited potent oral in vivo efficacy in potentiating the cytotoxic agent temozolomide in a B16F10 murine melanoma model.

MeSH terms

  • Administration, Oral
  • Animals
  • Antineoplastic Agents / chemical synthesis*
  • Antineoplastic Agents / pharmacokinetics
  • Antineoplastic Agents / pharmacology
  • Antineoplastic Agents, Alkylating
  • Benzimidazoles / chemical synthesis*
  • Benzimidazoles / pharmacokinetics
  • Benzimidazoles / pharmacology
  • Biological Availability
  • Cell Line, Tumor
  • Dacarbazine / analogs & derivatives
  • Dacarbazine / pharmacology
  • Drug Synergism
  • Female
  • Humans
  • Male
  • Melanoma, Experimental / drug therapy
  • Mice
  • Mice, Inbred C57BL
  • Neoplasm Transplantation
  • Oxadiazoles / chemical synthesis*
  • Oxadiazoles / pharmacokinetics
  • Oxadiazoles / pharmacology
  • Poly (ADP-Ribose) Polymerase-1
  • Poly(ADP-ribose) Polymerase Inhibitors*
  • Pyridines / chemical synthesis*
  • Pyridines / pharmacokinetics
  • Pyridines / pharmacology
  • Structure-Activity Relationship
  • Temozolomide
  • Transplantation, Heterologous

Substances

  • 2-(4-(1,3,4-oxadiazol-2-yl)phenyl)-1H-benzo(d)imidazole-4-carboxamide
  • 2-(4-(pyridin-2-yl)phenyl)-1H-benzo(d)imidazole-4-carboxamide
  • Antineoplastic Agents
  • Antineoplastic Agents, Alkylating
  • Benzimidazoles
  • Oxadiazoles
  • Poly(ADP-ribose) Polymerase Inhibitors
  • Pyridines
  • Dacarbazine
  • Parp1 protein, mouse
  • Poly (ADP-Ribose) Polymerase-1
  • Temozolomide