MGST1 drives lymph node metastasis in papillary thyroid carcinoma via mitochondrial metabolic reprogramming and...

While papillary thyroid carcinoma (PTC) generally exhibits a favorable prognosis, a subset of patients experiences poorer outcomes, with lymph node metastasis (LNM) significantly increasing the risk of recurrence and correlating with a worse prognosis. Mitochondrial metabolic reprogramming and immune evasion play pivotal roles in driving lymph node metastasis; however, the specific actionable targets within these processes remain largely unexplored.

We constructed a multi-omics discovery framework by integrating TCGA/GTEx transcriptomics, a large-scale independent clinical cohort, and single-cell RNA sequencing. Both mitochondrial metabolic signatures and immune evasion landscapes were investigated to characterize their roles in driving LNM. A consensus machine learning framework was deployed to isolate core drivers, which were rigorously validated through genetic manipulation and pharmacological assays.

Unsupervised clustering identified a high-risk "Mito-high" subtype, characterized by distinct metabolic reprogramming and an immunosuppressive microenvironment, in which CD8⁺ T cell depletion coincided with Treg enrichment. Machine learning prioritized MGST1 as the core predictor, consistently ranking as a top feature in both the integrated TCGA/GTEx dataset and our independent cohort. The MGST1-based model demonstrated robust predictive performance, achieving an AUC of 0.833 in external validation. At the single-cell level, trajectory analysis positioned MGST1 at the terminal stage of dedifferentiation, marking a stem-like metastatic subpopulation. Pharmacological inhibition of MGST1 with Toxoflavin dose-dependently suppressed proliferation, migration, and invasion while inducing apoptosis. Critically, pharmacological inhibition of MGST1 may reverse the "immune-cold" phenotype by promoting IL-1β release and suppressing TGF-β1. siRNA-mediated knockdown confirmed the target dependency of Toxoflavin.

Our findings uncover a previously unrecognized link between mitochondrial metabolic reprogramming, immune evasion and LNM in PTC and establish MGST1 as a robust biomarker for metastatic risk stratification and a pivotal metabolic-immune regulator. Moreover, the target-specific activity of toxoflavin provides a rational therapeutic strategy for patients with high-risk PTC characterized by MGST1-driven mitochondrial reprogramming and immune evasion.