Metabolic Rewiring in Response to Biguanides Is Mediated by mROS/HIF-1a in Malignant Lymphocytes

Abstract

Summary: Metabolic flexibility allows cells to adapt to various environments and limits the efficacy of metabolic drugs. Therapeutic targeting of cancer metabolism relies on defining limiting requirements and vulnerabilities in the highly dynamic metabolic network. Here, we characterize the metabolic reprogramming and identify cancer-specific metabolic vulnerabilities in response to the pharmacological inhibition of mitochondrial complex I. Our work reveals the adaptation mechanism in malignant lymphocytes providing resistance against the biguanides phenformin and metformin by transcriptionally reprogramming glucose metabolism. Metabolic adaptation to complex I inhibition is mediated by mitochondrial reactive oxygen species (mROS) serving as a mitochondrial stress signal activating hypoxia-inducible factor-1a (HIF-1a). Inhibition of the mROS/HIF-1a axis through antioxidants or direct suppression of HIF-1a selectively disrupts metabolic adaptation and survival during complex I dysfunction in malignant lymphocytes. Our results identify HIF-1a signaling as a critical factor in resistance against biguanide-induced mitochondrial dysfunction, allowing selective targeting of metabolic pathways in leukemia and lymphoma. : Khan et al. characterize the signaling mechanisms underlying metabolic adaptation and fuel utilization of malignant lymphocytes in response to mitochondrial dysfunction induced by biguanides. Suppression of HIF-1a selectively targets malignant lymphocytes by inducing synthetic lethality in response to metformin and phenformin. Keywords: metabolic flexibility, biguanides, mitochondria, HIF-1a, lymphoid malignancies