2. Academic Validation
  3. Kinetic and structural investigations of novel inhibitors of human epithelial 15-lipoxygenase-2

Kinetic and structural investigations of novel inhibitors of human epithelial 15-lipoxygenase-2

  • Bioorg Med Chem. 2021 Sep 15;46:116349. doi: 10.1016/j.bmc.2021.116349.
Wan-Chen Tsai 1,  Nathan C Gilbert 2,  Amanda Ohler 3,  Michelle Armstrong 1,  Steven Perry 1,  Chakrapani Kalyanaraman 4,  Adam Yasgar 5,  Ganesha Rai 5,  Anton Simeonov 5,  Ajit Jadhav 5,  Melissa Standley 1,  Hsiau-Wei Lee 1,  Phillip Crews 1,  Anthony T Iavarone 6,  Matthew P Jacobson 4,  David B Neau 7,  Adam R Offenbacher 3,  Marcia Newcomer 2,  Theodore R Holman 8
Affiliations

Affiliations

  • 1 Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA 95064, United States.
  • 2 Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, United States.
  • 3 Department of Chemistry, East Carolina University, Greenville, NC 27858, United States.
  • 4 Department of Pharmaceutical Chemistry, School of Pharmacy, University of California San Francisco, San Francisco, CA 94158, United States.
  • 5 National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Rockville, MD 20850, United States.
  • 6 Department of Chemistry and California Institute for Quantitative Biosciences (QB3), University of California Berkeley, Berkeley, CA 94720, United States.
  • 7 Cornell University, Northeastern Collaborative Access Team, Argonne National Laboratory, Argonne, IL, United States.
  • 8 Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA 95064, United States. Electronic address: holman@ucsc.edu.
PMID: 34500187 DOI: 10.1016/j.bmc.2021.116349
Abstract

Human epithelial 15-lipoxygenase-2 (h15-LOX-2, ALOX15B) is expressed in many tissues and has been implicated in atherosclerosis, cystic fibrosis and Ferroptosis. However, there are few reported potent/selective inhibitors that are active ex vivo. In the current work, we report newly discovered molecules that are more potent and structurally distinct from our previous inhibitors, MLS000545091 and MLS000536924 (Jameson et al, PLoS One, 2014, 9, e104094), in that they contain a central imidazole ring, which is substituted at the 1-position with a phenyl moiety and with a benzylthio moiety at the 2-position. The initial three molecules were mixed-type, non-reductive inhibitors, with IC50 values of 0.34 ± 0.05 μM for MLS000327069, 0.53 ± 0.04 μM for MLS000327186 and 0.87 ± 0.06 μM for MLS000327206 and greater than 50-fold selectivity versus h5-LOX, h12-LOX, h15-LOX-1, COX-1 and COX-2. A small set of focused analogs was synthesized to demonstrate the validity of the hits. In addition, a binding model was developed for the three imidazole inhibitors based on computational docking and a co-structure of h15-LOX-2 with MLS000536924. Hydrogen/deuterium exchange (HDX) results indicate a similar binding mode between MLS000536924 and MLS000327069, however, the latter restricts protein motion of helix-α2 more, consistent with its greater potency. Given these results, we designed, docked, and synthesized novel inhibitors of the imidazole scaffold and confirmed our binding mode hypothesis. Importantly, four of the five inhibitors mentioned above are active in an h15-LOX-2/HEK293 cell assay and thus they could be important tool compounds in gaining a better understanding of h15-LOX-2's role in human biology. As such, a suite of similar pharmacophores that target h15-LOX-2 both in vitro and ex vivo are presented in the hope of developing them as therapeutic agents.

Keywords

Cellular activity; Computational docking; Crystallography; Enzymology; Hydrogen-deuterium exchange; Inhibitor; Mixed inhibition; lipoxygenase.

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