CST1 suppresses ferroptosis and restricts CD8+ T-cell infiltration and effector function in lung adenocarcinoma via activation of the WNT/β-catenin signaling pathway.

Background

Ferroptosis dysregulation and immune evasion are central features of lung adenocarcinoma (LUAD) progression, yet the molecular mechanisms that coordinately govern both processes remain poorly understood. This study aimed to identify ferroptosis-associated genes in LUAD and characterize their functional and mechanistic roles in tumor progression and anti-tumor immunity.

Methods

Differentially expressed genes (DEGs) were identified from two GEO microarray datasets (GSE32863 and GSE118370) and intersected with a curated ferroptosis gene set from GeneCards. Expression and prognostic analyses were conducted using the TCGA-based GEPIA and KM Plotter databases. The functional role of CST1 was assessed in vitro via CCK-8, colony formation, ROS/Fe2+/GSH/MDA detection, and CD8+ T cell co-culture assays. Mechanistic studies employed WNT pathway inhibition with IWR-1. In vivo validation was performed using a syngeneic LLC tumor model in immunocompetent C57BL/6 mice.

Results

Nine ferroptosis-associated DEGs were identified in LUAD, among which CST1 was most consistently upregulated and significantly associated with shortened progression-free survival. CST1 knockdown suppressed LUAD cell proliferation, induced ferroptotic cell death as evidenced by elevated Fe2+, ROS, and MDA alongside GSH depletion, and enhanced CD8+ T cell chemotaxis and effector cytokine secretion. CST1 overexpression produced the opposing effects. Mechanistically, CST1 activated the WNT/β-catenin pathway, and pharmacological inhibition by IWR-1 reversed the pro-tumorigenic, ferroptosis-suppressive, and immunosuppressive phenotypes. In C57BL/6 mice, CST1 depletion reduced tumor growth, restored intratumoral ferroptosis markers, and increased CD8+ T cell infiltration.

Conclusions

CST1 promotes LUAD progression by simultaneously suppressing ferroptosis and impairing CD8+ T cell-mediated immunity through WNT/β-catenin activation. These findings identify the CST1-WNT/β-catenin axis as a candidate therapeutic target in LUAD.