Edward Gao

All Publications

• Small-molecule activator of SMUG1 enhances repair of pyrimidine lesions in DNA. DNA repair Gao, Y., McPherson, L., Adimoolam, S., Suresh, S., Wilson, D. L., Das, I., Park, E. R., Ng, C. S., Jun, Y. W., Ford, J. M., Kool, E. T. 2025; 146: 103809

  Abstract

  A potentially promising approach to targeted cancer prevention in genetically at-risk populations is the pharmacological upregulation of DNA repair pathways. SMUG1 is a base excision repair enzyme that ameliorates adverse genotoxic and mutagenic effects of hydrolytic and oxidative damage to pyrimidines. Here we describe the discovery and initial cellular activity of a small-molecule activator of SMUG1. Screening of a kinase inhibitor library and iterative rounds of structure-activity relationship studies produced compound 40 (SU0547), which activates SMUG1 by as much as 350 ± 60 % in vitro at 100 nM, with an AC50 of 4.3 ± 1.1 µM. To investigate the effect of compound 40 on endogenous SMUG1, we performed in vitro cell-based experiments with 5-hydroxymethyl-2'-deoxyuridine (5-hmdU), a pyrimidine oxidation product that is selectively removed by SMUG1. In several human cell lines, compound 40 at 3-5 µM significantly reduces the cytotoxicity of 5-hmdU and decreases levels of double-strand breaks induced by the damaged nucleoside. We conclude that the SMUG1 activator compound 40 is a useful tool to study the mechanisms of 5-hmdU toxicity and the potentially beneficial effects of suppressing damage to pyrimidines in cellular DNA.

  View details for DOI 10.1016/j.dnarep.2025.103809

  View details for PubMedID 39879855

• Convenient syntheses of isotopically labeled pyrimidine 2'-deoxynucleosides and their 5-hydroxy oxidation products. Nucleosides, nucleotides & nucleic acids Gao, Y., Kool, E. T. 2024: 1-23

  Abstract

  Hydrolytic and oxidative damage to pyrimidine nucleobases in DNA represents a significant source of mutations in the human genome. To better understand how these lesions are incorporated and repaired in human cells, it is desirable to have ready access to isotopically enriched nucleosides for use in isotope tracing and mass spectrometry-based quantification experiments. Here we report on improved syntheses of deoxyuridine, deoxycytidine, 5-hydroxydeoxyuridine, and 5-hydroxydeoxycytidine nucleosides labeled with 13C and 15N. Deoxyuridine was synthesized from uracil in a direct glycosylation reaction with excellent stereoselectivity without the need to reduce a ribonucleoside intermediate. Deoxyuridine was further converted to deoxycytidine using mild O4 activation conditions with high efficiency. Finally, we document the synthetic details of preparative oxidation of deoxyuridine and deoxycytidine to their 5-hydroxy counterparts. Overall, our protocols avoid hazardous reagents and tedious conditions found in previous methods.

  View details for DOI 10.1080/15257770.2024.2437038

  View details for PubMedID 39652906