Astragaloside IV suppresses triple-negative breast cancer cell migration and invasion by targeting BCAT1-mediated branched-chain amino acid metabolism.

Branched-chain amino acid (BCAA) transaminase 1 (BCAT1), the rate-limiting enzyme in BCAA metabolism, serves a pivotal role in tumor progression. Astragaloside IV (AS-IV) exhibits potential antitumor properties; however, whether AS-IV suppresses breast cancer migration by modulating BCAA metabolism via BCAT1 remains to be elucidated. The present study aimed to investigate whether AS-IV inhibits the invasion and migration of MDA-MB-231 triple-negative breast cancer (TNBC) cells by targeting BCAT1-mediated BCAA metabolic reprogramming. The present study used network pharmacology to predict AS-IV targets against breast cancer invasion, followed by BCAT1 knockdown and overexpression in MDA-MB-231 cells. Using molecular docking, cellular thermal shift assay, wound healing, Transwell, western blotting, quantitative PCR and liquid chromatography-mass spectrometry metabolomics, the present study systematically evaluated: i) AS-IV-BCAT1 direct binding and protein stability; ii) BCAA metabolic flux regulation via the branched-chain α-ketoacid dehydrogenase kinase (BCKDK)/branched-chain α-ketoacid dehydrogenase (BCKDH) axis; and iii) functional impacts on breast cancer cell migration and invasion. Network pharmacology predicted BCAT1 as a key potential target of AS-IV, with significant enrichment of the BCAA metabolic pathway. The results of the present study suggested that AS-IV binds to and stabilizes BCAT1 in vitro, an effect that is associated with reduced migration and invasion of MDA-MB-231 cells. It also promotes BCAA degradation via the BCKDK/BCKDH axis, lowering intracellular BCAA levels and suppressing malignancy. Notably, AS-IV maintained dose-dependent inhibition even with BCAT1 knockdown or overexpression, albeit with reduced efficacy. In conclusion, the present study suggested that AS-IV suppresses MDA-MB-231 cell invasion and migration by targeting BCAT1-mediated BCAA metabolism. These findings support further evaluation of AS-IV in TNBC and highlight BCAA metabolism as a potential intervention point in future research.