181135-44-4Relevant articles and documents
Resistance-modifying agents. 9. Synthesis and biological properties of benzimidazole inhibitors of the DNA repair enzyme poly(ADP-ribose) polymerase
White,Almassy,Calvert,Curtin,Griffin,Hostomsky,Maegley,Newell,Srinivasan,Golding
, p. 4084 - 4097 (2007/10/03)
The nuclear enzyme poly(ADP-ribose) polymerase (PARP) facilitates the repair of DNA strand breaks and is implicated in the resistance of cancer cells to certain DNA-damaging agents. Inhibitors of PARP have clinical potential as resistance-modifying agents capable of potentiating radiotherapy and the cytotoxicity of some forms of cancer chemotherapy. The preclinical development of 2-aryl-1H-benzimidazole-4-carboxamides as resistance-modifying agents in cancer chemotherapy is described. 1H-Benzimidazole-4-carboxamides, particularly 2-aryl derivatives, are identified as a class of potent PARP inhibitors. Derivatives of 2-phenyl-1H-benzimidazole-4-carboxamide (23, K(i) = 15 nM), in which the phenyl ring contains substituents, have been synthesized. Many of these derivatives exhibit K(i) values for PARP inhibition 10 nM, with 2-(4-hydroxymethylphenyl)-1H-benzimidazole-4-carboxamide (78, K(i) = 1.6 nM) being one of the most potent. Insight into structure-activity relationships (SAR) for 2-aryl-1H-benzimidazole-4-carboxamides has been enhanced by studying the complex formed between 2-(3-methoxyphenyl)-1H-benzimidazole-4-carboxamide (44, K(i) = 6 nM) and the catalytic domain of chicken PARP. Important hydrogen-bonding and hydrophobic interactions with the protein have been identified for this inhibitor. 2-(4-Hydroxyphenyl)-1H-benzimidazole-4-carboxamide (45, K(i) = 6 nM) potentiates the cytotoxicity of both temozolomide and topotecan against A2780 cells in vitro (by 2.8- and 2.9-fold, respectively).
Novel benzimidazole and quinazolinone inhibitors of the DNA repair enzyme Poly(ADP-ribose)polymerase
Griffin,Srinivasan,White,Bowman,Calvert,Curtin,Newell,Golding
, p. 43 - 47 (2007/10/03)
Two novel series of inhibitors of the DNA repair enzyme poly(ADP-ribose)polymerase (PARP) were synthesized and evaluated for biological activity. In the benzimidazole-4-carboxamide series, the carbamoyl function was restricted into the putative biologically active conformation via an intramolecular hydrogen bond, while for quinazolin-4-[3H]-ones this was achieved by incorporation of the group into a heterocyclic ring. For both series of compounds, syntheses involved acylation of substituted anthranilic acid derivatives, followed by acid- or base-catalysed cyclization. 8-Hydroxyquinazolin-4-[3H]-ones were prepared from the corresponding 8-methoxy compounds by dealkylation with boron tribromide. PARP inhibitory activity was determined in permeabilized L1210 murine leukaemia cells, in comparison with the established inhibitor 3-hydroxybenzamide (IC50 = 8.3 μM). For both series, inhibitory activity varied with the nature of the 2-substituent, with benzimidazole-4-carboxamides proving approximately tenfold more potent than the previously prepared benzoxazole-4-carboxamides. 2-Arylbenzimidazoles were especially active, and 2-(4-methoxyphenyl)benzimidazole-4-carboxamide (IC50 = 60 nM) is the most potent PARP inhibitor reported to date. In the quinazolinone series, a 2-(4-nitrophenyl) substituent, and either an 8-methyl or 8-hydroxy group conferred potent inhibitory activity, with IC50 values of 0.13 and 0.23 μM, respectively, being observed.
