A Novel Role for DNA-PK in Metabolism by Regulating Glycolysis in Castration Resistant Prostate Cancer

PURPOSE: DNA-dependent kinase catalytic subunit (DNA-PKcs, herein referred as DNA-PK) is a multifunctional kinase of high cancer relevance. DNA-PK is deregulated in multiple tumor types, including prostate cancer (PCa), and is associated with poor outcomes. DNA-PK was previously nominated as a therapeutic target and DNA-PK inhibitors are currently undergoing clinical investigation. While DNA-PK is well studied in DNA repair and transcriptional regulation, much remains to be understood about the way by which DNA-PK drives aggressive disease phenotypes. EXPERIMENTAL DESIGN: Here, unbiased proteomic and metabolomic approaches in clinically relevant tumor models uncovered a novel role of DNA-PK in metabolic regulation of cancer progression. DNA-PK regulation of metabolism was interrogated using pharmacological and genetic perturbation using in vitro cell models, in vivo xenografts, and ex vivo in patient-derived explants (PDE). RESULTS: Key findings reveal: i) the first-in-field DNA-PK protein-protein interactome; ii) numerous DNA-PK novel partners involved in glycolysis, iii) DNA-PK interacts with, phosphorylates (in vitro) and increases the enzymatic activity of glycolytic enzymes ALDOA and PKM2, iv) DNA-PK drives synthesis of glucose-derived pyruvate and lactate, v) DNA-PK regulates glycolysis in vitro, in vivo and ex vivo, and vi) combination of DNA-PK inhibitor with glycolytic inhibitor 2-deoxyglucose leads to additive anti-proliferative effects in aggressive disease. CONCLUSIONS: Findings herein unveil novel DNA-PK partners, substrates, and function in PCa. The role of DNA-PK impacts glycolysis through direct interaction with glycolytic enzymes and modulation of enzymatic activity. These events support energy production that may contribute to generation and/or maintenance of DNA-PK-mediated aggressive disease phenotypes.