Medicinal Chemistry and NMR Driven Discovery of Novel UDP-glucuronosyltransferase 1A Inhibitors That Overcome Therapeutic Resistance in Cells

Michael J. Osborne, Anamika Sulekha, Biljana Culjkovic-Kraljacic, Jadwiga Gasiorek, Edward Ruediger, Eric Jolicouer, Anne Marinier, Sarit Assouline, Katherine L.B. Borden*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

The UDP glucuronosyltransferases (UGT) deactivate many therapeutics via glucuronidation while being required for clearance of normal metabolites and xenobiotics. There are 19 UGT enzymes categorized into UGT1A and UGT2B families based on sequence conservation. This presents a challenge in terms of targeting specific UGTs to overcome drug resistance without eliciting overt toxicity. Here, we identified for the first time that UGT1A4 is highly elevated in acute myeloid leukemia (AML) patients and its reduction corresponded to objective clinical responses. To develop inhibitors to UGT1A4, we leveraged previous NMR-based fragment screening data against the C-terminal domain of UGT1A (UGT1A-C). NMR and medicinal chemistry strategies identified novel chemical matter based on fragment compounds with the capacity to bind ∼20 fold more tightly to UGT1A-C (Kd ∼ 600 μM vs ∼30 μM). Some compounds differentially inhibited UGT1A4 versus UGT1A1 enzyme activity and restored drug sensitivity in resistant human cancer cells. NMR-based NOE experiments revealed these novel compounds recognised a region distal to the catalytic site suggestive of allosteric regulation. This binding region is poorly conserved between UGT1A and UGT2B C-terminal sequences, which otherwise exhibit high similarity. Consistently, these compounds did not bind to the C-terminal domain of UGT2B7 nor a triple mutant of UGT1A-C replaced with UGT2B7 residues in this region. Overall, we discovered a site on UGTs that can be leveraged to differentially target UGT1As and UGT2Bs, identified UGT1A4 as a therapeutic target, and found new chemical matter that binds the UGT1A C-terminus, inhibits glucuronidation and restores drug sensitivity.

Original languageEnglish (US)
Article number168378
JournalJournal of Molecular Biology
Volume436
Issue number2
DOIs
StatePublished - Jan 15 2024

Funding

This research was supported by the following grants to KLBB: IRIC Centre for COmmersialization (IRICoR), LLS USA TRP 6478 , NIH RO1 CA98571 and NIH RO1 CA80728 . KLBB holds a Canada Research Chair in Molecular Biology of the Cell Nucleus.

Keywords

  • cancer drug resistance
  • nuclear magnetic resonance
  • UGT enzymes

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Molecular Biology

Fingerprint

Dive into the research topics of 'Medicinal Chemistry and NMR Driven Discovery of Novel UDP-glucuronosyltransferase 1A Inhibitors That Overcome Therapeutic Resistance in Cells'. Together they form a unique fingerprint.

Cite this