SRD5A3-mediated aberrant N-glycosylation of SCARA5 promotes ferroptosis in lung adenocarcinoma.

Lung cancer remains the leading cause of cancer-related mortality globally. While N-glycosylation has been found to be a critical post-translational modification in multiple malignancies, the role of N-glycosylation-associated proteins in lung adenocarcinoma (LUAD) remains poorly defined. In this study, steroid 5α-reductase 3 (SRD5A3), a key regulator of N-glycosylation metabolism, was identified as a highly expressed molecule in LUAD, with its upregulation correlating with unfavourable patient outcomes. Functional assays demonstrated that SRD5A3 depletion markedly suppressed the proliferation, invasion, and migration of A549 and H1299 cells, thereby restraining tumour progression by triggering ferroptosis. Mechanistically, loss of SRD5A3 caused aberrant hyper-N-glycosylation of the SCARA5 protein, which impaired its interaction with ferritin light chain (FTL) and promoted FTL degradation. This process released free Fe²⁺, induced lipid peroxidation via the Fenton reaction, and ultimately, triggered ferroptosis. The glycosylation inhibitor tunicamycin reversed the ferroptosis sensitivity induced by SRD5A3 knockdown, confirming N-glycosylation as the core regulatory node. Further, site-directed mutagenesis assays revealed that the N397Q mutation of SCARA5 abolished its pro-ferroptotic effect. Collectively, these findings establish a "glycosylation-ferroptosis axis" regulatory model, uncovering a novel mechanism by which SRD5A3 modulates ferroptosis by mediating SCARA5 glycosylation.