Fatty acid and cysteine metabolic interplay regulate ferroptosis and highlight <scp>xCT</scp> as a selenium‐chrysin target in breast carcinoma

Cancer metabolic remodeling impacts the entire network of metabolic pathways, and strategies that target various points within this system could contribute to successfully abrogating cancer cell survival. Fatty acids (FAs) are essential to cancer cells because they support membrane biosynthesis during proliferation and provide energy during metabolic stress. Fatty acid transport protein 1 (FATP1)has been shown to mediate FA uptake in breast carcinoma (BC). The light chain of cysteine/glutamate amino acid exchange transporter system Xc (xCT)is crucial for the uptake of cysteine serving as a carbon and sulfur source that contributes to redox control, bioenergetics, and biosynthesis. In this study, targeting of FA and cysteine metabolic pathways was shown to be a potential strategy for managing BC by inhibiting FATP1 and xCT with arylpiperazine 5k and selenium-chrysin (SeChry), respectively. In BC cell lines, FATP1 expression is controlled by estrogen receptor β (ER-β) and promotes the accumulation of lipid droplets (LDs), which is associated with triple-negative breast carcinoma (TNBC) cells showing increased rates of cell proliferation, two-dimensional directional cell migration, and higher chemoresistance. Expression of xCT was also associated with the TNBC molecular BC subtype. In BC specimens, an association between FATP1 and xCT expression was observed. In vitro, SeChry induced ferroptosis in BC cells by targeting xCT and cysteine reliance and ultimately inducing cell death. In xenograft BC tumors, arylpiperazine 5k abrogated the effects of SeChry encapsulated in polyurea dendrimers functionalized with folate (SeChry@PURE_G4-FA₂) by reducing intracellular FA and rescuing ferroptosis. In vitro, SeChry sensitized BC cells to cisplatin and may therefore serve as an alternative in combination therapy. Overall, our study confirmed FATP1 as a marker and xCT as both a marker and a target in BC, particularly in TNBC. Induction of ferroptosis by interfering with xCT function may provide an opportunity to improve BC treatment, and a therapeutic approach using SeChry@PURE_G4-FA₂ is a promising strategy. © 2026 The Pathological Society of Great Britain and Ireland.