Ophiobolin A Covalently Targets Mitochondrial Complex IV Leading to Metabolic Collapse in Cancer Cells

 Flor A. Gowans, Danny Q. Thach, Zhouyang Zhu, Yangzhi Wang, Belen E. Altamirano Poblano, Dustin Dovala, John A. Tallarico, Jeffrey M. McKenna, Markus Schirle, Thomas J. Maimone, and Daniel K. Nomura

ACS Chemical Biology 2024

DOI: 10.1021/acschembio.4c00064

Ophiobolin A (OPA) is a sesterterpenoid fungal natural product with broad anticancer activity. While OPA possesses multiple electrophilic moieties that can covalently react with nucleophilic amino acids on proteins, the proteome-wide targets and mechanism of OPA remain poorly understood in many contexts. In this study, we used covalent chemoproteomic platforms to map the proteome-wide reactivity of the OPA in a highly sensitive lung cancer cell line. Among several proteins that OPA engaged, we focused on two targets: lysine-72 of cytochrome c oxidase subunit 5A (COX5A) and cysteine-53 of mitochondrial hypoxia induced gene 1 domain family member 2A (HIGD2A). These two subunit proteins are part of complex IV (cytochrome C oxidase) within the electron transport chain and contributed significantly to the antiproliferative activity of OPA. OPA activated mitochondrial respiration in a COX5A- and HIGD2A-dependent manner, leading to an initial spike in mitochondrial ATP and heightened mitochondrial oxidative stress. OPA compromised mitochondrial membrane potential, ultimately leading to ATP depletion. We have used chemoproteomic strategies to discover a unique anticancer mechanism of OPA through activation of complex IV leading to compromised mitochondrial energetics and rapid cell death.

Discovery and Preclinical Characterization of BIIB129, a Covalent, Selective, and Brain-Penetrant BTK Inhibitor for the Treatment of Multiple Sclerosis

Martin K. Himmelbauer, Bekim Bajrami, Rebecca Basile, Andrew Capacci, TeYu Chen, Colin K. Choi, Rab Gilfillan, Felix Gonzalez-Lopez de Turiso, Chungang Gu, Marc Hoemberger, Douglas S. Johnson, J. Howard Jones, Ekta Kadakia, Melissa Kirkland, Edward Y. Lin, Ying Liu, Bin Ma, Tom Magee, Srinivasa Mantena, Isaac E. Marx, Claire M. Metrick, Michael Mingueneau, Paramasivam Murugan, Cathy A. Muste, Prasad Nadella, Marta Nevalainen, Chelsea R. Parker Harp, Vatee Pattaropong, Alicia Pietrasiewicz, Robin J. Prince, Thomas J. Purgett, Joseph C. Santoro, Jurgen Schulz, Simone Sciabola, Hao Tang, H. George Vandeveer, Ti Wang, Zain Yousaf, Christopher J. Helal, and Brian T. Hopkins

Journal of Medicinal Chemistry 2024

DOI: 10.1021/acs.jmedchem.4c00220

Multiple sclerosis (MS) is a chronic disease with an underlying pathology characterized by inflammation-driven neuronal loss, axonal injury, and demyelination. Bruton’s tyrosine kinase (BTK), a nonreceptor tyrosine kinase and member of the TEC family of kinases, is involved in the regulation, migration, and functional activation of B cells and myeloid cells in the periphery and the central nervous system (CNS), cell types which are deemed central to the pathology contributing to disease progression in MS patients. Herein, we describe the discovery of BIIB129 (25), a structurally distinct and brain-penetrant targeted covalent inhibitor (TCI) of BTK with an unprecedented binding mode responsible for its high kinome selectivity. BIIB129 (25) demonstrated efficacy in disease-relevant preclinical in vivo models of B cell proliferation in the CNS, exhibits a favorable safety profile suitable for clinical development as an immunomodulating therapy for MS, and has a low projected total human daily dose.

Histidine-Covalent Stapled Alpha-Helical Peptides Targeting hMcl-1

Giulia Alboreggia, Parima Udompholkul, Carlo Baggio, Kendall Muzzarelli, Zahra Assar, and Maurizio Pellecchia

Journal of Medicinal Chemistry 2024

DOI: 10.1021/acs.jmedchem.4c00277

Several novel and effective cysteine targeting (Cys) covalent drugs are in clinical use. However, the target area containing a druggable Cys residue is limited. Therefore, methods for creating covalent drugs that target different residues are being looked for; examples of such ligands include those that target the residues lysine (Lys) and tyrosine (Tyr). Though the histidine (His) side chain is more frequently found in protein binding locations and has higher desirable nucleophilicity, surprisingly limited research has been done to specifically target this residue, and there are not many examples of His-targeting ligands that have been rationally designed. In the current work, we created novel stapled peptides that are intended to target hMcl-1 His 252 covalently. We describe the in vitro (biochemical, NMR, and X-ray) and cellular design and characterization of such agents. Our findings further suggest that the use of electrophiles to specifically target His residues is warranted.