title: Imidazoquinolinone, imidazopyridine, and isoquinolindione derivatives as novel and potent inhibitors of the poly(ADP-ribose) polymerase (PARP): a comparison with standard PARP inhibitors.
abstract: We have identified three novel structures for inhibitors of the poly(ADP-ribose) polymerase (PARP), a nuclear enzyme activated by strand breaks in DNA and implicated in DNA repair, apoptosis, organ dysfunction or necrosis. 2-[4-(5-Methyl-1H-imidazol-4-yl)-piperidin-1-yl]-4,5-dihydro-imidazo[4,5,1-i,j]quinolin-6-one (BYK49187), 2-(4-pyridin-2-yl-phenyl)-4,5-dihydro-imidazo[4,5,1-i,j]quinolin-6-one (BYK236864), 6-chloro-8-hydroxy-2,3-dimethyl-imidazo-[1,2-alpha]-pyridine (BYK20370), and 4-(1-methyl-1H-pyrrol-2-ylmethylene)-4H-isoquinolin-1,3-dione (BYK204165) inhibited cell-free recombinant human PARP-1 with pIC(50) values of 8.36, 7.81, 6.40, and 7.35 (pK(i) 7.97, 7.43, 5.90, and 7.05), and murine PARP-2 with pIC(50) values of 7.50, 7.55, 5.71, and 5.38, respectively. BYK49187, BYK236864, and BYK20370 displayed no selectivity for PARP-1/2, whereas BYK204165 displayed 100-fold selectivity for PARP-1. The IC(50) values for inhibition of poly(ADP-ribose) synthesis in human lung epithelial A549 and cervical carcinoma C4I cells as well in rat cardiac myoblast H9c2 cells after PARP activation by H(2)O(2) were highly significantly correlated with those at cell-free PARP-1 (r(2) = 0.89-0.96, P < 0.001) but less with those at PARP-2 (r(2) = 0.78-0.84, P < 0.01). The infarct size caused by coronary artery occlusion and reperfusion in the anesthetized rat was reduced by 22% (P < 0.05) by treatment with BYK49187 (3 mg/kg i.v. bolus and 3 mg/kg/h i.v. during 2-h reperfusion), whereas the weaker PARP inhibitors, BYK236864 and BYK20370, were not cardioprotective. In conclusion, the imidazoquinolinone BYK49187 is a potent inhibitor of human PARP-1 activity in cell-free and cellular assays in vitro and reduces myocardial infarct size in vivo. The isoquinolindione BYK204165 was found to be 100-fold more selective for PARP-1. Thus, both compounds might be novel and valuable tools for investigating PARP-1-mediated effects.
authors.affiliation: University of Konstanz, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Eltze
authors.forename: Rainer
authors.initials: R
authors.lastname: Boer
authors.forename: Thomas
authors.initials: T
authors.lastname: Wagner
authors.forename: Steffen
authors.initials: S
authors.lastname: Weinbrenner
authors.forename: Michelle C
authors.initials: MC
authors.lastname: McDonald
authors.forename: Christoph
authors.initials: C
authors.lastname: Thiemermann
authors.forename: Alexander
authors.initials: A
authors.lastname: Bürkle
authors.forename: Thomas
authors.initials: T
authors.lastname: Klein
mesh_terms: D000818:Animals; D002460:Cell Line; D045744:Cell Line, Tumor; D005347:Fibroblasts / Q000187:drug effects / Q000201:enzymology; D006801:Humans; D007093:Imidazoles / Q000737:chemistry / Q000494:pharmacology*; D007546:Isoquinolines / Q000737:chemistry / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D051379:Mice; D009203:Myocardial Infarction / Q000188:drug therapy / Q000473:pathology; D015428:Myocardial Reperfusion Injury / Q000188:drug therapy / Q000473:pathology; D009206:Myocardium / Q000473:pathology; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D011065:Poly(ADP-ribose) Polymerases / Q000096:biosynthesis; D011725:Pyridines / Q000737:chemistry / Q000494:pharmacology*; D015363:Quinolones / Q000737:chemistry / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors; D012995:Solubility; D013329:Structure-Activity Relationship
chemical_list: D007093:Imidazoles; D007546:Isoquinolines; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D011725:Pyridines; D015363:Quinolones; D011994:Recombinant Proteins; D011065:Poly(ADP-ribose) Polymerases