ADSL-produced fumarate increases BECN1 dimethylation to promote autophagy and liver tumor growth.

Abstract

Cancer cells depend on the reprogramming of cell metabolism to constantly adapt metabolically to the tumor microenvironment. ADSL (adenylosuccinate lyase), a rate-limiting enzyme in de novo purine synthesis, is overexpressed in various cancer cells. However, whether ADSL functions in other oncogenic signaling is largely unknown. Here, our recent study shows that ADSL interacts with BECN1 (beclin 1) to regulate macroautophagy/autophagy upon lipid deprivation. Mechanistically, ADSL is phosphorylated at S140 by EIF2AK3/PERK (eukaryotic translation initiation factor 2 alpha kinase 3) in response to lipid deprivation, which enhances the association between ADSL and BECN1. ADSL-produced fumarate reduces the BECN1-associated KDM8 activity, leading to increased BECN1 K117 dimethylation. BECN1 K117 dimethylation inhibits its interaction with BCL2 to initiate autophagy. Targeting the ADSL-BECN1 axis by knock-in mutation or a cell-penetrating peptide inhibits autophagy and blunts liver tumor growth in mice. These findings broaden the physiological significance of ADSL in autophagy and liver tumor development.Abbreviation: α-KG: alpha-ketoglutarate; ADSL: adenylosuccinate lyase; AMP: adenosine monophosphate; EIF2AK3/PERK: eukaryotic translation initiation factor 2 alpha kinase 3; HCC: hepatocellular carcinoma; KDM8: lysine demethylase 8; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; ULK1: unc-51 like autophagy activating kinase 1; WIPI2: WD repeat domain, phosphoinositide interacting 2.