Abstract 5116: Stress-induced AMPK interactome analysis reveals novel protein-protein interactions associated with chromatin remodeling in acute lymphoblastic leukemia

Abstract Acute lymphoblastic leukemia (ALL) is a leading cause of cancer-related death among children, adolescents and young adults. We previously reported that ALL cells are vulnerable to metabolic stress conditions following AMP-activated protein kinase (AMPK) activation, leading to cell death. AMPK is the master metabolic regulator, and we and others have reported it interacts with chromatin-associated proteins to regulate gene expression in response to metabolic stress. To investigate AMPK’s mechanistic role in epigenetic gene regulation under metabolic stress, and identify new AMPK partners, we performed a comprehensive interactome analysis using TurboID-based proximity labeling proteomics. We generated HEK293T cells stably expressing TurboID fused to the AMPKα1, AMPKα2, AMPKβ1 or AMPKγ1. Following treatment with the allosteric AMPK activator PF-06409577 (PF064) for 1h, to mimic the cell’s rapid response to energy/metabolic stress, the samples underwent mass spectrometry-based proteomics. Proteomics data analysis identified novel altered (enhanced or reduced) AMPK protein-protein interactions (PPI) following PF064 treatment. The GO analysis of proteins interacting with AMPK showed that metabolic stress enhances PPIs involved in regulating gene expression, cellular metabolic processes, DNA repair, chromatin organization, histone modifications, etc. More importantly, we identified that AMPK interacted with members of the non-canonical Polycomb repressive complex 1 (PRC1.1) such as PCGF1, RING1, KDM2B, BCORL1, USP7. PRC1 is a known epigenetic regulator that monoubiquitinylates histone H2A at Lys119 (H2AK119ub) to control transcription and regulate gene expression. Using Co-IP, we confirmed these interactions in KASUMI-2 (Bp-ALL) and KE-37 (T-ALL) cells. When cells were treated with PF064 or 991 (another AMPK activator), we found that the interactions of AMPK with the catalytic core of PCR1.1 (PCGF1, RING1) were increased compared to untreated cells. To examine the effect of activated AMPK on PCR1.1 activity, we determined the level of H2AK119ub in ALL cells treated with PF064 and 991 for 1h. We found that the level of H2AK119ub protein expression was increased in ALL-treated cells indicating the PRC1.1 was activated. Together, these data suggest that stress-induced AMPK activation increased the catalytic activity of the PRC1.1 via PPI in ALL. Our findings are consistent with our previous published RNA-Seq and ChIP-Seq data indicating an epigenetic role for AMPK in altering gene expression examined under metabolic stress (two thirds exhibited downregulation), and provide insights into the AMPK-driven mechanism(s) involved. Further elucidation of the uncovered PPIs and its mechanistic role(s) may lead to potential epigenetic-based strategies to overcome resistance/refractoriness in ALL and other malignancies. Citation Format: Anna Shvab, Guy J. Leclerc, Julio C. Barredo. Stress-induced AMPK interactome analysis reveals novel protein-protein interactions associated with chromatin remodeling in acute lymphoblastic leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5116.