Glutaminolysis promotes cancer-associated angiogenesis via the GLS1-TNC signaling pathway

Glutaminolysis, a metabolic pathway in which glutamine is converted into glutamate and subsequently into alpha-ketoglutarate, supports cancer progression by supplying energy and biosynthetic precursors that sustain tumor cell growth, survival, and metabolic flexibility. While its metabolic functions have been extensively studied, its contribution to tumor angiogenesis is not well defined. In this study, we demonstrate that knockdown of glutaminase 1 (GLS1), a key regulator of glutaminolysis, in head and neck cancer (HNC) xenografts markedly reduced intratumoral CD31⁺ endothelial cells, consistent with impaired angiogenesis. In vitro, HUVECs exposed to exosomes from GLS1-deficient HNC cells exhibited diminished migratory capacity and reduced tube formation compared with those treated with control-derived exosomes. Proteomic analysis by LC-MS revealed that exosomes lacking GLS1 were deficient in tenascin-C (TNC), a matricellular protein with established pro-angiogenic activity. Mechanistic studies showed that GLS1 loss triggered USP1-dependent proteasomal degradation of caveolin-1 (CAV1), a critical regulator of exosome biogenesis. Because CAV1 promotes the incorporation of TNC into exosomes, GLS1 deficiency disrupted the CAV1-TNC signaling axis, resulting in exosomes lacking pro-angiogenic cargo. Consequently, these defective exosomes failed to activate extracellular matrix remodeling and adhesion pathways in HUVECs, thereby limiting endothelial migration and angiogenic capacity. Together, these findings uncover a previously unrecognized role for GLS1 in promoting tumor angiogenesis and further suggest that targeting GLS1 could not only suppress tumor metabolism but also inhibit angiogenesis in HNC.