Transcriptional and translational alterations induced by BET protein inhibition and its combination with Omaveloxolone in acute myeloid leukemia

The inhibition of bromodomain and extra-terminal domain (BET) protein family achieved promising preclinical results as epigenetic therapy in acute myeloid leukemia (AML). However, clinical data showed a limited activity of bromodomain inhibitor (BETi) as single agent. We aimed to investigate the role of hypoxia in the response of AML cells to BET inhibition in order to identify a novel therapeutic combination targeting leukemia stem-progenitor cells (LSPCs) in their niche. BETi maintained an anti-proliferative and pro-apoptotic activity at low oxygen concentration by modulating the leukemic transcriptional, translational and metabolic programs towards reduced ribosome biogenesis, altered polyamine metabolism and activation of a TNF- via NF-B signature at translational level, especially in hypoxic conditions. Accordingly, Omaveloxolone, a clinical-stage NF-B inhibitor and NFR2 activator approved for Friedreich’s ataxia, significantly enhanced the efficacy of BETi against AML cell lines in hypoxia and normoxia by reducing cell viability and enhancing apoptosis. At molecular level, the drug combination converged to the downregulation of MYC, the DNA replication and oxidative phosphorylation signatures while forcing the expression of antioxidant genes. Overall, the combination of BETi and Oma disrupts key metabolic and transcriptional programs essential to AML cell survival and LSPC maintenance in the hypoxic microenvironment.

• Type: Other
• Archive: European Genome-phenome Archive (EGA)