Glutamate dehydrogenase 1 (GDH1) sustains triple-negative breast cancer persister cell survival by coordinating mitochondrial fusion and anaplerotic flux

Chemotherapeutic treatment destroys the majority of cancer cells, but a small percentage survives through genetic and non-genetic pathways. These surviving cells, known as drug-tolerant persister (DTP) cells, are major causes of tumor recurrence. This study aimed to identify key factors regulating DTP cells in triple-negative breast cancer (TNBC) and to elucidate the underlying mechanisms conferring their survival advantage. In this study, we found that glutamate dehydrogenase 1 (GDH1) plays a critical role in DTP cell survival by regulating epithelial-to-mesenchymal transition (EMT), mitochondrial metabolism and fusion-associated remodeling. Bioinformatic analyses of publicly available datasets revealed that elevated GDH1 expression in breast cancer patients correlates with poor prognosis. Western, qRT-PCR, and immunofluorescence analyses confirmed GDH1 upregulation in DTP cells, which was further supported by mass spectrometry and extracellular flux assay. Cell viability and wound healing assays demonstrated that GDH1 upregulation enhanced DTP cell viability and migratory capacity, whereas suppression reversed it. Moreover, stable GDH1 knockdown impaired EMT and DTP formation. Silencing GDH1 significantly disrupted mitochondrial function and induced apoptotic cell death in DTP cells. Notably, GDH1 expression declined after 30 days of drug withdrawal, suggesting a transient regulatory role during DTP state. In vivo xenograft experiments further demonstrated that chemotherapeutic treatment in GDH1 knockdown xenografts significantly enhances chemosensitivity. The reduction of proliferation markers Ki-67 and PCNA in GDH1-deficient xenografts further confirmed its role in tumor progression. Collectively, our data suggest that GDH1 is a crucial regulator of DTP survival and targeting it may represent a promising therapeutic strategy to overcome chemoresistance in TNBC.