FADS2 Mediated Nrf2-SLC7A11 Axis Activation Promotes Breast Ductal Carcinoma in Situ Progression via Glutamate Efflux

Elucidating the progression mechanism from ductal carcinoma in situ (DCIS), a non-obligate precursor of invasive ductal carcinoma (IDC), remains a critical challenge in oncology. Metabolic profiling of lesions with differential invasiveness may help reveal key drivers underlying DCIS progression. This study employed mass spectrometry imaging to delineate the small-molecule metabolic profiles of DCIS, DCIS with synchronous IDC, and IDC lesions. Key metabolic alterations driving DCIS-to-IDC progression were identified, including elevated fatty acid biosynthesis in tumor tissues. Comparative analyses revealed that IDC exhibited significantly higher accumulation of polyunsaturated fatty acids (PUFAs) than DCIS (P<0.05), consistent with immunohistochemical validation showing upregulated fatty acid desaturase 2 expression in IDC. DCIS lesions predominantly accumulated phosphatidylinositols with saturated/monounsaturated acyl chains, while IDC exhibited a marked enrichment of phosphatidylinositols with PUFA (P<0.01). Furthermore, IDC showed significantly reduced levels of antioxidant molecules (taurine, ascorbic acid, glutathione) and the detoxification enzyme glutathione S-transferase mu 2 compared to DCIS (P<0.05), indicating dysregulation of redox homeostasis. Strikingly, DCIS with synchronous IDC displayed metabolic signatures closely aligned with IDC, suggesting its role as a transitional state during malignant progression. These findings indicate that DCIS malignant progression exhibits metabolic dependency on PUFAs/phosphatidylinositols with PUFA and depletion of antioxidants. Therapeutic targeting of PUFA biosynthesis or redox homeostasis regulators may offer novel translational approaches for tracking and intercepting DCIS progression.