Journal Article

Inhibition of DNA Glycosylases via Small Molecule Purine Analogs

Calkins, Marcus J., Dorjsuren, Dorjbal, Jaruga, Pawel, Lloyd, R. Stephen, Simeonov, Anton, McCullough, Amanda K., Maloney, David, Dizdaroglu, Miral, Jacobs, Aaron C., Jadhav, Ajit

2013

Overview

Following the formation of oxidatively-induced DNA damage, several DNA glycosylases are required to initiate repair of the base lesions that are formed. Recently, NEIL1 and other DNA glycosylases, including OGG1 and NTH1 were identified as potential targets in combination chemotherapeutic strategies. The potential therapeutic benefit for the inhibition of DNA glycosylases was validated by demonstrating synthetic lethality with drugs that are commonly used to limit DNA replication through dNTP pool depletion via inhibition of thymidylate synthetase and dihydrofolate reductase. Additionally, NEIL1-associated synthetic lethality has been achieved in combination with Fanconi anemia, group G. As a prelude to the development of strategies to exploit the potential benefits of DNA glycosylase inhibition, it was necessary to develop a reliable high-throughput screening protocol for this class of enzymes. Using NEIL1 as the proof-of-principle glycosylase, a fluorescence-based assay was developed that utilizes incision of site-specifically modified oligodeoxynucleotides to detect enzymatic activity. This assay was miniaturized to a 1536-well format and used to screen small molecule libraries for inhibitors of the combined glycosylase/AP lyase activities. Among the top hits of these screens were several purine analogs, whose postulated presence in the active site of NEIL1 was consistent with the paradigm of NEIL1 recognition and excision of damaged purines. Although a subset of these small molecules could inhibit other DNA glycosylases that excise oxidatively-induced DNA adducts, they could not inhibit a pyrimidine dimer-specific glycosylase.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Adducts / Alkaloids / Analogs / Anemia / Animals / Biochemistry / Cell cycle / Chemotherapy / Cytotoxicity / Deoxyribonuclease (Pyrimidine Dimer) - antagonists & inhibitors / Deoxyribonuclease (Pyrimidine Dimer) - chemistry / Deoxyribonuclease (Pyrimidine Dimer) - metabolism / Deoxyribonucleic acid / Development strategies / Dihydrofolate reductase / DNA / DNA adducts / DNA biosynthesis / DNA damage / DNA glycosylase / DNA Glycosylases - antagonists & inhibitors / DNA Glycosylases - chemistry / DNA Glycosylases - metabolism / DNA methylation / DNA repair / DNA replication / DNA-(Apurinic or Apyrimidinic Site) Lyase - antagonists & inhibitors / DNA-(Apurinic or Apyrimidinic Site) Lyase - chemistry / DNA-(Apurinic or Apyrimidinic Site) Lyase - metabolism / Drugs / Enzymatic activity / Enzyme Assays / Enzyme Inhibitors - chemistry / Enzyme Inhibitors - pharmacology / Enzymes / Fanconi syndrome / Fanconi's anemia / Fibroblasts - cytology / Fibroblasts - drug effects / Fibroblasts - enzymology / Fluorescence / Genomes / Health aspects / High-throughput screening / Humans / Hydrolases / Inhibition / Kinetics / Lesions / Lethality / Ligases / Medical screening / Mice / NTH1 protein / OGG1 protein / Oligodeoxynucleotides / Oligonucleotides / Oxidation-Reduction / Protein Binding / Purines / Purines - chemistry / Purines - pharmacology / Pyrimidines / Recombinant Proteins - chemistry / Recombinant Proteins - metabolism / Science / Small Molecule Libraries - chemistry / Small Molecule Libraries - pharmacology / Substrate Specificity / Target recognition / Toxicology