Venetoclax causes metabolic reprogramming independent of BCL-2 inhibition

• Published in: Cell death & disease 2020-08, Vol.11 (8), p.616-616, Article 616
• Main Authors: Roca-Portoles, Alba, Rodriguez-Blanco, Giovanny, Sumpton, David, Cloix, Catherine, Mullin, Margaret, Mackay, Gillian M., O’Neill, Katelyn, Lemgruber, Leandro, Luo, Xu, Tait, Stephen W. G.
• Format: Article
• Language: English
• Subjects: 13/31; 13/44; 631/45/320; 631/80/82/23; Activating Transcription Factor 4 - metabolism; Animals; Antibodies; Apoptosis; Bax protein; bcl-2 Homologous Antagonist-Killer Protein - metabolism; Bcl-2 protein; bcl-2-Associated X Protein - metabolism; Biochemistry; Biomedical and Life Sciences; Bridged Bicyclo Compounds, Heterocyclic - pharmacology; Carboxylation; Cell Biology; Cell Culture; Cell death; Cell Death - drug effects; Cell Line, Tumor; Cellular stress response; Chronic lymphocytic leukemia; Citric Acid Cycle - drug effects; Cytotoxicity; HEK293 Cells; Humans; Immunology; Leukemia; Life Sciences; Metabolism; Metabolism - drug effects; Mice; Mitochondria; Mitochondria - drug effects; Mitochondria - metabolism; Mitochondria - ultrastructure; Proto-Oncogene Proteins c-bcl-2 - antagonists & inhibitors; Respiration; Sulfonamides - pharmacology; Tricarboxylic acid cycle
• ISSN: 2041-4889; 2041-4889
• DOI: 10.1038/s41419-020-02867-2

BH3-mimetics are a new class of anti-cancer drugs that inhibit anti-apoptotic Bcl-2 proteins. In doing so, BH3-mimetics sensitise to cell death. Venetoclax is a potent, BCL-2 selective BH3-mimetic that is clinically approved for use in chronic lymphocytic leukaemia. Venetoclax has also been shown to inhibit mitochondrial metabolism, this is consistent with a proposed role for BCL-2 in metabolic regulation. We used venetoclax to understand BCL-2 metabolic function. Similar to others, we found that venetoclax inhibited mitochondrial respiration. In addition, we also found that venetoclax impairs TCA cycle activity leading to activation of reductive carboxylation. Importantly, the metabolic effects of venetoclax were independent of cell death because they were also observed in apoptosis-resistant BAX/BAK-deficient cells. However, unlike venetoclax treatment, inhibiting BCL-2 expression had no effect on mitochondrial respiration. Unexpectedly, we found that venetoclax also inhibited mitochondrial respiration and the TCA cycle in BCL-2 deficient cells and in cells lacking all anti-apoptotic BCL-2 family members. Investigating the basis of this off-target effect, we found that venetoclax-induced metabolic reprogramming was dependent upon the integrated stress response and ATF4 transcription factor. These data demonstrate that venetoclax affects cellular metabolism independent of BCL-2 inhibition. This off-target metabolic effect has potential to modulate venetoclax cytotoxicity.