Article
作者: Wilhelm, Brian T ; Hébert, Josée ; Barabé, Frédéric ; Lisi, Véronique ; Tran, Thai Hoa ; Audemard, Éric ; Bilodeau, Mélanie ; Roussy, Mathieu ; Duval, Michel ; Lavallée, Vincent-Philippe ; Laramée, Louise ; Simpson, Shawn M ; Fatima, Furat ; Gendron, Patrick ; El-Hachem, Nehme ; Jouan, Loubna ; Teira, Pierre ; Théret, Louis ; Cardin, Sophie ; Smith, Martin A ; Farah, Azer ; Jammali, Safa ; Aubert, Léo ; Gruber, Tanja A ; Khakipoor, Banafsheh ; Bonneil, Éric ; Rouette, Alexandre ; Sauvageau, Guy ; Gress, Verena ; Chagraoui, Jalila ; Roux, Philippe P ; Thibault, Pierre ; Paré, Bastien ; Santiago, Raoul ; Boulianne, Luc ; Cellot, Sonia ; Bittencourt, Henrique
Abstract:Acute megakaryoblastic leukemia (AMKL) is a rare, developmentally restricted, and highly lethal cancer of early childhood. The paucity and hypocellularity (due to myelofibrosis) of primary patient samples hamper the discovery of cell- and genotype-specific treatments. AMKL is driven by mutually exclusive chimeric fusion oncogenes in two-thirds of the cases, with CBFA2T3::GLIS2 (CG2) and NUP98 fusions (NUP98r) representing the highest-fatality subgroups. We established CD34+ cord blood–derived CG2 models (n = 6) that sustain serial transplantation and recapitulate human leukemia regarding immunophenotype, leukemia-initiating cell frequencies, comutational landscape, and gene expression signature, with distinct upregulation of the prosurvival factor B-cell lymphoma 2 (BCL2). Cell membrane proteomic analyses highlighted CG2 surface markers preferentially expressed on leukemic cells compared with CD34+ cells (eg, NCAM1 and CD151). AMKL differentiation block in the mega-erythroid progenitor space was confirmed by single-cell profiling. Although CG2 cells were rather resistant to BCL2 genetic knockdown or selective pharmacological inhibition with venetoclax, they were vulnerable to strategies that target the megakaryocytic prosurvival factor BCL-XL (BCL2L1), including in vitro and in vivo treatment with BCL2/BCL-XL/BCL-W inhibitor navitoclax and DT2216, a selective BCL-XL proteolysis-targeting chimera degrader developed to limit thrombocytopenia in patients. NUP98r AMKL were also sensitive to BCL-XL inhibition but not the NUP98r monocytic leukemia, pointing to a lineage-specific dependency. Navitoclax or DT2216 treatment in combination with low-dose cytarabine further reduced leukemic burden in mice. This work extends the cellular and molecular diversity set of human AMKL models and uncovers BCL-XL as a therapeutic vulnerability in CG2 and NUP98r AMKL.