Inhibition of ERO1A by TCF21 curbs aerobic glycolysis and enhances immune recognition in lung adenocarcinoma.

Background: Among the many malignancies, lung adenocarcinoma (LUAD) is a top global health and life risk. The focus of this research is to explore how the TCF21/ERO1A pathway influences the immune escape mechanisms triggered by aerobic glycolysis in LUAD.

Methods: After downloading mRNA expression data from TCGA-LUAD and conducting differential expression analysis, we identified our target mRNA based on literature review. We used the hTFtarget database to forecast the upstream transcription factor (TF) of the target mRNA, and their binding relationship was verified through dual-luciferase experiments. Gene set enrichment analysis (GSEA) was performed on the target gene to probe its impact on LUAD-associated signaling pathways. qRT-PCR was used to detect the expression of ERO1A, TCF21, and PD-L1 mRNA. Western blot was employed to measure the expression levels of glycolysis-related proteins (SLC2A1, HK2, LDHA) and PD-L1 protein. Extracellular acidification rate and oxygen consumption rate were evaluated using a Seahorse metabolic analyzer. The apoptosis of CD8 T cells and the activation status of CD8 T cells were detected by flow cytometry. We also conducted 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) assay to assess the cytotoxicity of natural killer cells against LUAD cells.

Results: High expression levels of ERO1A were observed in LUAD tissues and cells. GSEA identified a notable association of ERO1A with glycolytic processes and tumor immune evasion pathways. The depletion of ERO1A deeply impaired the glycolytic capacity, immune evasion abilities, and PD-L1 expression in LUAD cells, as validated by both cellular and molecular experiments. ERO1A induced immune evasion in LUAD cells via the upregulation of PD-L1. TCF21, an upstream regulator of ERO1A, was found to be downregulated in LUAD. Dual-luciferase assays also provided evidence for the specific binding of ERO1A to TCF21. Recovery experiments showed TCF21 curbed the stimulatory effect of glycolysis on the immune evasion of LUAD cells by suppressing ERO1A expression.

Conclusion: TCF21 directs its action towards ERO1A, thereby inhibiting the glycolysis-mediated promotion of immune evasion in LUAD cells. As such, the TCF21/ERO1A axis could be harnessed as a therapeutic target and a prognosis marker in LUAD.