Identification and mechanism of action analysis of the new PARP-1 inhibitor 2″-hydroxygenkwanol A

• Published in: Biochimica et biophysica acta Vol. 1850; no. 9; pp. 1806 - 1814
• Main Authors: Dal Piaz, Fabrizio, Ferro, Piera, Vassallo, Antonio, Vasaturo, Michele, Forte, Giovanni, Chini, Maria Giovanna, Bifulco, Giuseppe, Tosco, Alessandra, De Tommasi, Nunziatina
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.09.2015
• Subjects: active sites; Biflavonoids; Catalytic Domain; diabetes; Drug Evaluation, Preclinical; Enzyme Inhibitors - pharmacology; flavonoids; Flavonoids - pharmacology; HeLa Cells; Humans; inflammation; ligands; Mass spectrometry; mechanism of action; medicinal properties; Models, Molecular; Molecular Docking Simulation; Molecular modeling; NAD ADP-ribosyltransferase; neoplasms; neurodegenerative diseases; nicotine; PARP-1; pathogenesis; Plant compounds; Poly (ADP-Ribose) Polymerase-1; Poly(ADP-ribose) Polymerase Inhibitors; polyphenols; proteolysis; recombinant proteins; screening; Spiro Compounds - pharmacology; Surface Plasmon Resonance; traditional medicine; NAD; Surface Plasmon Resonance; Biflavonoids; SPR; MS; Molecular modeling; PARP-1; Plant compounds; Mass spectrometry
• ISSN: 0304-4165; 0006-3002; 1872-8006
• DOI: 10.1016/j.bbagen.2015.05.014

Poly(ADP-ribose) polymerase 1 (PARP-1) activity has been implicated in the pathogenesis of numerous diseases as cancer, inflammation, diabetes and neurodegenerative disorders, therefore the research for new PARP-1 inhibitors is still an active area. To identify new potential PARP-1 inhibitors, we performed a screening of a small-molecule library consisting of polyphenols isolated from plants used in the traditional medicine, by Surface Plasmon Resonance (SPR). Biochemical and cellular assays were performed to confirm SPR results and select the promising candidate(s). Finally, limited proteolysis and ligand docking analyses allowed defining the protein region involved in the interaction with the putative inhibitor(s). The dimeric spiro-flavonoid 2″-hydroxygenkwanol A, member of a relatively recently discovered class of flavonoids containing a spirane C-atom, has been identified as possible PARP-1 inhibitor. This compound showed a high affinity for the polymerase (KD: 0.32±0.05μM); moreover PARP-1 activity in the presence of 2″-hydroxygenkwanol A was significantly affected both when using the recombinant protein and when measuring the cellular effects. Finally, our study suggests this compound to efficiently interact with the protein catalytic domain, into the nicotine binding pocket. 2″-hydroxygenkwanol A efficiently binds and inhibits PARP-1 at submicromolar concentrations, thus representing a promising lead for the design of a new class of PARP-1 modulators, useful as therapeutic agents and/or biochemical tools. Our study has identified an additional class of plant molecules, the spiro-biflavonoids, with known beneficial pharmacological properties but with an unknown mechanism of action, as a possible novel class of PARP-1 activity inhibitors. •We demonstrated that dimeric spiro-flavonoids bind PARP-1.•2″-hydroxygenkwanol A efficiently modulates PARP-1 both in vitro and in cell.•This molecule binds the nicotine binding pocket of the protein.•It represents a promising lead for the design of a new class of PARP-1 inhibitors.