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Principal Investigator: Loren David Walensky
Organization: DANA-FARBER CANCER INST
Fiscal Year: 2024
Award: $999,639
Funding agency: National Cancer Institute
PROJECT SUMMARY/ABSTRACT
BCL-2 proteins participate in a dynamic interaction network that determines whether a cell will live or die.
Deregulation of this essential signaling pathway underlies the pathogenesis of human cancer and resistance to
treatment. The goal of this R35 research program is to elucidate the fundamental protein interaction mechanisms
that drive the apoptotic program and harness these insights to develop next-generation cancer treatments. Over
the last five years of R35 support, we applied novel chemical tools and a host of analytical technologies to
achieve mechanistic discoveries that revealed new druggable binding sites and compounds to target them. We
found that covalent modification of distinct cysteines in pro-apoptotic BAX and anti-apoptotic MCL-1 and BFL-1
differentially regulate their apoptotic functions. Our pursuit of covalent ligands that mimic these post-translational
modifications are yielding prototype BAX activators and MCL-1 and BFL-1 inhibitors for cancer therapy.
Deciphering how BAX and BAK are directly activated, and the conformational mechanisms that underlie their
conversion from latent monomers into toxic mitochondrial oligomers, has also been a major focus of our work.
Indeed, the elusive structures of the BAX and BAK death channels represent the “holy grail” of apoptosis
research. We recently generated the first full-length homogeneous BAX oligomer (BAXO) amenable to structure-
function characterizations, providing a glimpse into the macromolecular organization of a functional BAXO
species. BAXO and its mutants are enabling us to pinpoint the structural determinants for each step of the BAX-
activation pathway and thus inform new control points for pharmacologic activation of apoptosis. In addition to
dissecting these high-priority, canonical BCL-2 protein interactions, we have developed proteomic tools to
identify non-canonical targets and recently found that MCL-1 directly interacts with the fatty acid oxidation
enzyme VLCAD, revealing a dual role for MCL-1 at the intersection of apoptosis and metabolic regulation. We
hypothesize that MCL-1-driven cancers rely on both apoptotic suppression and fatty acid metabolism to
maximize pathologic survival, potentially explaining why MCL-1 is the most widely expressed anti-apoptotic
protein across human cancers. Here, we build on our newest mechanistic insights to interrogate a spectrum of
BCL-2 family interactions that drive human cancer and mine each opportunity to pharmacologically subvert them.
Specifically, our next set of R35 goals are: (1) identify the structural and functional determinants that mediate
the “execution phase” of mitochondrial apoptosis; (2) solve the structure of a BAX oligomer; (3) characterize the
non-canonical role of MCL-1 at the intersection of apoptosis and cancer metabolism; and (4) advance the
development and in vivo testing of BCL-2 family molecular modulators as next-generation therapies for human
cancer. We tackle these goals using multidisciplinary approaches that span chemistry, structural biology,
proteomics, biochemistry, cell biology, and in vivo testing. As a chemical biologist and pediatric oncologist, I am
committed to transforming our fresh mechanistic insights into new therapies for relapsed and refractory cancers.
Terms: <Advanced Development><Apoptosis><Apoptosis Pathway><Apoptotic><B cell lymphoma 2><B-Cell CLL/Lymphoma 2 Gene><B-Cell CLL/lymphoma 2><B-Cell Chronic Lymphocytic Leukemia Associated Oncogene><B-cell Leukemia 1><B-cell lymphoma protein 2><B-cell lymphoma/leukemia-2><BAX><BAX gene><BCL><BCL-2 Protein><BCL1 Oncogene><BCL2><BCL2 gene><BCL2 protein><BCL2-Associated X Protein Gene><BCL2L4><Bcl-2><Binding><Binding Sites><Biochemistry><Biological Chemistry><Cancer Biology><Cancer Treatment><Cancers><Cell Body><Cells><Cellular biology><Cessation of life><Chemicals><Chemistry><Chemoresistance><Combining Site><Cysteine><Death><Development><Enzyme Gene><Enzymes><Family><Fatty Acid Metabolism Pathway><Goals><Half-Cystine><Human><In vivo analysis><L-Cysteine><Length><Ligands><Long-Chain-Acyl-CoA Dehydrogenase><Long-Chain-Acyl-Coenzyme A Dehydrogenase><MCL-1><MCL1><MCL1 gene><Maintenance><Malignant Neoplasm Therapy><Malignant Neoplasm Treatment><Malignant Neoplasms><Malignant Tumor><Mediating><Metabolic><Mitochondria><Modern Man><Modification><Molecular><Molecular Configuration><Molecular Conformation><Molecular Interaction><Molecular Stereochemistry><Pathogenesis><Pathologic><Pathway interactions><Pediatric Oncologist><Permeability><Phase><Post-Translational Modification Protein/Amino Acid Biochemistry><Post-Translational Modifications><Post-Translational Protein Modification><Post-Translational Protein Processing><Posttranslational Modifications><Posttranslational Protein Processing><Programmed Cell Death><Protein Family><Protein Modification><Proteins><Proteomics><Reactive Site><Regulation><Relapse><Research><Resistance><Role><Signal Pathway><Structure><Surface><Technology><VLCAD><Very-Long-Chain Acyl-CoA Dehydrogenase><Work><anti-cancer therapy><bcl-2 Genes><cancer cell metabolism><cancer metabolism><cancer therapy><cancer-directed therapy><ced9 homolog><cell biology><chemoresistant><chemotherapy resistance><chemotherapy resistant><conformation><conformational><conformational state><conformationally><conformations><developmental><fatty acid metabolism><fatty acid oxidation><in vivo evaluation><in vivo testing><inhibitor><insight><interdisciplinary approach><malignancy><mitochondrial><monomer><multidisciplinary approach><mutant><myeloid cell leukemia 1><myeloid cell leukemia sequence 1><myeloid leukemia cell differentiation protein><neoplasm/cancer><new drug treatments><new drugs><new pharmacological therapeutic><new therapeutics><new therapy><next generation><next generation therapeutics><novel><novel drug treatments><novel drugs><novel pharmaco-therapeutic><novel pharmacological therapeutic><novel therapeutics><novel therapy><pathway><pharmacologic><programs><prototype><refractory cancer><resistant><resistant cancer><social role><structural biology><structural determinants><structural factors><tool><tumor cell metabolism><tumor metabolism>