Loss of FBXO11 establishes a stem cell program in acute myeloid leukemia by dysregulating LONP1

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Abstract

Acute myeloid leukemia (AML) is an aggressive cancer with very poor outcomes. To identify additional drivers of leukemogenesis, we analyzed sequencing data from 1,727 unique individual AML patients, which revealed mutations in ubiquitin ligase family genes in 11.2% of adult AML samples with mutual exclusivity. The SKP1/CUL1/F-box (SCF) E3 ubiquitin ligase complex gene, FBXO11, was the most significantly downregulated gene of the SCF complex in AML. We found that FBXO11 interacts with and catalyzes K63-linked ubiquitination of LONP1 in the cytosol, to promote LONP1 entry into mitochondria. We show that depletion of FBXO11 or LONP1 reduces mitochondrial respiration through impaired LONP1 chaperone activity to assemble electron transport chain Complex IV. Reduced mitochondrial respiration secondary to FBXO11 or LONP1 depletion imparted myeloid-biased stem cell properties in primary CD34+ hematopoietic stem and progenitor cells (HSPC) in vitro. In a human xenograft model, depletion of FBXO11 cooperated with AML1-ETO and mutant KRASG12D to generate serially transplantable AML. Our findings suggest that reduced FBXO11 cooperates to initiate AML by priming HSPC for myeloid-biased self-renewal through attenuation of LONP1-mediated regulation of mitochondrial respiration.

Authors

Hayle Kincross, Ya-Chi Angela Mo, Xuan Wang, Linda Chang, Gerben Duns, Franziska Mey, Jihong Jiang, Zurui Zhu, Naomi Isak, Harwood Kwan, Tammy T.Y. Lau, T. Roderick Docking, Pranav Garg, Jessica Tran, Shane Colborne, Se-Wing Grace Cheng, Shujun Huang, Nadia Gharaee, Elijah Willie, Jeremy D.K. Parker, Joshua Bridgers, Davis Wood, Ramon I. Klein Geltink, Gregg B. Morin, Aly Karsan