Myeloid differentiation-associated autophagy drives venetoclax resistance in AML

Acute myeloid leukemia (AML) is a complex disease that often displays phenotypic and genotypic heterogeneity, where subclones are either refractory or frequently become resistant to treatment. Several studies have shown that the developmental stage of leukemia correlates with the response to therapies combining the BCL2 inhibitor venetoclax (Ven) with hypomethylating agents, such as azacitidine (Aza), where phenotypically primitive AML cells are sensitive and monocytic cells are more resistant. Here we show that resistant monocytic subclones have higher autophagic flux compared to sensitive primitive subclones in AMLs of mixed phenotype. Induction of AML myeloid differentiation with inecalcitol, a potent vitamin D3 analogue and vitamin D receptor (VDR) agonist, increases autophagic flux and Ven/Aza resistance. Pharmacological inhibition or genetic perturbation of autophagy negates differentiation-induced Ven/Aza resistance. We show that this myeloid differentiation-associated autophagy increases mitochondrial reserve capacity and metabolic flexibility. This work shows that autophagy-dependent metabolic rewiring during AML differentiation contributes to Ven/Aza therapy resistance.