title: Targeting PARP-1 allosteric regulation offers therapeutic potential against cancer.
abstract: PARP-1 is a nuclear protein that has important roles in maintenance of genomic integrity. During genotoxic stress, PARP-1 recruits to sites of DNA damage where PARP-1 domain architecture initiates catalytic activation and subsequent poly(ADP-ribose)-dependent DNA repair. PARP-1 inhibition is a promising new way to selectively target cancers harboring DNA repair deficiencies. However, current inhibitors target other PARPs, raising important questions about long-term off-target effects. Here, we propose a new strategy that targets PARP-1 allosteric regulation as a selective way of inhibiting PARP-1. We found that disruption of PARP-1 domain-domain contacts through mutagenesis held no cellular consequences on recruitment to DNA damage or a model system of transcriptional regulation, but prevented DNA-damage-dependent catalytic activation. Furthermore, PARP-1 mutant overexpression in a pancreatic cancer cell line (MIA PaCa-2) increased sensitivity to platinum-based anticancer agents. These results not only highlight the potential of a synergistic drug combination of allosteric PARP inhibitors with DNA-damaging agents in genomically unstable cancer cells (regardless of homologous recombination status), but also signify important applications of selective PARP-1 inhibition. Finally, the development of a high-throughput PARP-1 assay is described as a tool to promote discovery of novel PARP-1 selective inhibitors.
authors.affiliation: Authors' Affiliations: Departments of Biochemistry and Molecular Biology and Surgery, Division of Surgical Research, The Jefferson Pancreas, Biliary, and Related Cancer Center; and Department of Cancer Biology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania.
authors.forename: Jamin D
authors.initials: JD
authors.lastname: Steffen
authors.forename: Renee M
authors.initials: RM
authors.lastname: Tholey
authors.forename: Marie-France
authors.initials: MF
authors.lastname: Langelier
authors.forename: Jamie L
authors.initials: JL
authors.lastname: Planck
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Schiewer
authors.forename: Shruti
authors.initials: S
authors.lastname: Lal
authors.forename: Nikolai A
authors.initials: NA
authors.lastname: Bildzukewicz
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Yeo
authors.forename: Karen E
authors.initials: KE
authors.lastname: Knudsen
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Brody
authors.forename: John M
authors.initials: JM
authors.lastname: Pascal
mesh_terms: D000494:Allosteric Regulation; D000818:Animals; D003001:Cloning, Molecular; D004249:DNA Damage; D006367:HeLa Cells; D057166:High-Throughput Screening Assays; D006801:Humans; D051379:Mice; D008958:Models, Molecular; D058990:Molecular Targeted Therapy; D016296:Mutagenesis; D009944:Organoplatinum Compounds / Q000494:pharmacology; D010190:Pancreatic Neoplasms / Q000188:drug therapy* / Q000201:enzymology* / Q000235:genetics; D000071137:Poly (ADP-Ribose) Polymerase-1; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D011065:Poly(ADP-ribose) Polymerases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D014162:Transfection
chemical_list: D009944:Organoplatinum Compounds; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; C499320:PARP1 protein, human; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases