Engineered flavonoid disrupts mitochondrial AIF/CHCHD4 complex for targeted cancer therapy

Cancer metabolism depends on multifaceted mechanisms, including bidirectional inter-organelle communication between mitochondria and the nucleus, facilitating cellular adaptation at the transcriptomic, proteomic, and metabolomic levels. The mitochondrial protein complex composed of apoptosis-inducing factor (AIF) and coiled-coil-helix-coiled-coil-helix domain-containing protein 4 (CHCHD4) is essential for this mitochondrio-nuclear communication. The AIF/CHCHD4 complex mediates the mitochondrial import of cysteine-enriched nuclear gene-encoded proteins, thereby adapting the mitochondrial proteome to cellular energy demands. Here, we report the discovery of M30-E05, a compound that binds to the NADH pocket of AIF, preventing its dimerization and disrupting the AIF/CHCHD4 complex, as demonstrated by molecular docking and gel electrophoresis analysis of mitochondrial AIF/CHCHD4 substrate expression. In cancer cells, M30-E05 reduces the expression of nuclear gene-encoded mitochondrial proteins such as AIF, CHCHD4, cytochrome c oxidase copper chaperone (COX17), and Mitochondrial calcium uptake 1 (MICU1). In addition, M30-E05 fragments the mitochondrial network and impairs mitochondrial respiration, causing profound alterations, particularly in glucose, lipid, and amino acid metabolism, as revealed by kinetic measurements of oxygen consumption and mass spectrometric metabolomics. Importantly, M30-E05 significantly reduces the viability of a human adult and pediatric osteosarcoma cancer cell panel, including those from patient-derived xenografts (PDX) of osteosarcomas, and induces apoptosis. When orally administered for two weeks to immunodeficient NSG mice, M30-E05 inhibited tumor growth in a subcutaneous PDX xenograft model without apparent toxicity. We anticipate that M30-E05, as a first-in-class metabolic inhibitor, could serve as the lead compound for a new class of antineoplastic agents.