Mechanistic study of regulatory T cells resisting ferroptosis under hypoxic stress in oral squamous cell carcinoma
10.12016/j.issn.2096-1456.202660123
- Author:
GUO Ruiyu
1
;
ZHANG Fangyu
1
;
XU Qin
1
;
CHEN Wantao
1
;
YAN Ming
1
Author Information
1. Department of Oral and Maxillofacial Head and Neck Oncology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, College of Stomatology, Shanghai Jiao Tong University, National Center for Stomatology, National Clinical Research Center for Oral Disease, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology
- Publication Type:Journal Article
- Keywords:
oral squamous cell carcinoma;
tumor immunity;
hypoxic microenvironment;
regulatory T cells;
cholesterol metabolism;
ferroptosis;
emopamil-binding protein;
7-dehydrocholesterol
- From:
Journal of Prevention and Treatment for Stomatological Diseases
2026;34(10):953-969
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To explore the metabolic molecular mechanism of regulatory T cells (Tregs) resisting ferroptosis under a hypoxic stress microenvironment, and to provide scientific support for finding intervention targets to improve the immune microenvironment of oral squamous cell carcinoma (OSCC).
Methods:This study was approved by the Institutional Medical Ethics Committee. Multiplex immunofluorescence was used to detect the distribution of Tregs and the localization of hypoxic regions in clinical pathological specimens from patients with OSCC tissues. Animal experiments were approved by the Laboratory Animal Ethics Committee. A tumor-bearing model was established in C57BL/6 mice. The submandibular, subscapular, inguinal, and popliteal lymph nodes were collected along with the spleen, and were homogenized to prepare single cell suspensions. C57BL/6 mouse naive CD4⁺ T cells were induced to differentiate into Tregs in vitro, and a 1% hypoxic culture model was established. Normoxia and hypoxia groups were established, and Treg viability under hypoxic conditions was assessed by flow cytometry. Transcriptomics and metabolomics were applied to analyze differentially expressed genes, metabolic pathways, and changes in cholesterol metabolites. Western blot was performed to detect the expression of emopamil-binding protein (EBP), glutathione peroxidase 4 (GPX4), ferroptosis suppressor protein 1 (FSP1), and acyl-CoA synthetase long-chain family member 4 (ACSL4). The safe concentration of the EBP inhibitor TASIN-30 was determined by the CCK-8 assay. On this basis, four groups were established: normoxia control, hypoxia, hypoxia+TASIN-30, and hypoxia+TASIN-30+7-dehydrocholesterol (7-DHC). Treg viability in each group was measured by flow cytometry; intracellular Fe2+ content, lipid peroxidation level, and reactive oxygen species (ROS) accumulation were detected by cellular immunofluorescence and flow cytometry; the reduced/oxidized glutathione (GSH/GSSG) ratio was measured using a microplate reader; and mitochondrial morphology was observed by transmission electron microscopy. In vivo tumor-inhibition experiments in C3H/HeJ mice were performed to validate the in vivo effects of EBP inhibition, and clinical prognostic survival analysis based on the TCGA-HNSC cohort was performed to evaluate the clinical prognostic value of ferroptosis resistance in Tregs.
Results:Tregs were highly enriched in OSCC tissue, preferentially accumulated in hypoxic areas, and could maintain cell survival under hypoxia. The cholesterol metabolism pathway was upregulated in the hypoxic group, with increased EBP mRNA expression (P < 0.001) and 7-DHC accumulation. Compared with the hypoxic group alone, the hypoxic + TASIN-30 group showed decreased GPX4 and FSP1 expression (P < 0.001, P = 0.003); increased ACSL4 expression (P < 0.001); a decreased viable cell ratio (P < 0.001); increased Fe2+, lipid peroxidation, and ROS levels (P < 0.001); a decreased GSH/GSSG ratio (P < 0.001); and mitochondrial shrinkage. Exogenous supplementation of 7-DHC reversed the effects of EBP inhibition. In vivo inhibition of EBP significantly inhibited tumor growth (P < 0.001).
Conclusion:Tregs upregulate EBP and promote 7-DHC accumulation in hypoxic microenvironments, thereby inhibiting Treg ferroptosis and maintaining their survival and immunosuppressive function. Inhibition of EBP can weaken the resistance of Tregs to ferroptosis under hypoxia.
