Metabolic Rewiring Is Essential for AML Cell Survival to Overcome Autophagy Inhibition by Loss of ATG3

Abstract

Autophagy is an important survival mechanism that allows recycling of nutrients and removal of damaged organelles and has been shown to contribute to the proliferation of acute myeloid leukemia (AML) cells. However, little is known about the mechanism by which autophagy- dependent AML cells can overcome dysfunctional autophagy. In our study we identified autophagy related protein 3 (ATG3) as a crucial autophagy gene for AML cell proliferation by conducting a CRISPR/Cas9 dropout screen with a library targeting around 200 autophagy-related genes. shRNA-mediated loss of ATG3 impaired autophagy function in AML cells and increased their mitochondrial activity and energy metabolism, as shown by elevated mitochondrial ROS generation and mitochondrial respiration. Using tracer-based NMR metabolomics analysis we further demonstrate that the loss of ATG3 resulted in an upregulation of glycolysis, lactate production, and oxidative phosphorylation. Additionally, loss of ATG3 strongly sensitized AML cells to the inhibition of mitochondrial metabolism. These findings highlight the metabolic vulnerabilities that AML cells acquire from autophagy inhibition and support further exploration of combination therapies targeting autophagy and mitochondrial metabolism in AML.

Deciphering the mitophagy receptor network identifies a crucial role for OPTN (optineurin) in acute myeloid leukemia

“…Mitochondrial respiration was measured by the oxygen consumption rate (OCR) using the XF Cell Mito Stress Test Kit (Agilent Technologies, 103015–100) on a 96-well Seahorse Bioscience Extracellular Flux Analyzer XF96 (Agilent Technologies) as described previously [ 66 ]. Murine or human cells (5 × 10 5 or 2 × 10 5 , respectively) were seeded in the stress assay medium as described by the manufacturer in XF96 Polystyrene Cell Culture Microplate for 1 h at 37°C without CO 2 .…”

Proteomic profiling of plasma exosomes from patients with B-cell acute lymphoblastic leukemia

“…In turn, inhibition of autophagy reduced B-ALL cell survival and proliferation 17 . Evidences have found the high expression of ATG3 in various cancers, containing colon cancer 36 , hepatocellular carcinoma 37 , and acute myeloid leukemia 38 , which promoted the development of cancers through accelerating autophagy. Whereas the expression and function of ATG3 in B-ALL id rarely explored.…”

Crosstalk between autophagy and metabolism: implications for cell survival in acute myeloid leukemia

“…Similarly, Baker et al reported that shRNA-mediated ATG3 deletion impaired the autophagy function of AML cells, leading to the upregulation of glycolysis, lactate production, and mitochondrial metabolism in AML cells. Furthermore, the deletion of ATG3 sensitized AML cells to the inhibition of oxidative phosphorylation (OXPHOS), highlighting the metabolic vulnerabilities that leukemia cells acquire from autophagy inhibition [ 54 ].…”