Thioredoxin related transmembrane protein 1acts as a prognostic indictor and promotes proliferation and TMZ resistance of lower-grade glioma

Thioredoxin Related Transmembrane Protein 1 (TMX1) encodes a thiol-disulfide oxidoreductase and regulates cleavage, formation, or isomerization of disulfide bonds among cysteine residues in proteins. Using bioinformatic analysis, we firstly prove TMX1 is significantly upregulated in lower-grade gliomas (LGGs) and associated with poor prognosis of LGG patients. Besides, it's also highly expressed in higher WHO grade, 1p/19q non-co-deleted and isocitrate dehydrogenase (IDH) wildtype LGGs, thus we established a TMX1-based nomogram model, which exhibits a strong and stable predictive ability in the prognosis of LGG patients. Then, we also noticed that TMX1 was significantly associated with the immune cell infiltrations in LGGs, especially in B cell, CD8⁺ T cell, CD4⁺T cell, dendritic cell, macrophage and neutrophil. Meanwhile, it was also highly correlated to the expressions of MKI67, PCNA, PROM1 and SOX2 in LGGs, and that higher TMX1 LGGs showed a stronger resistance to temozolomide (TMZ). Finally, in our in vitro and in vivo experiments, we verified that TMX1 is highly expressed in LGG patients clinically, and it not only regulates the proliferative ability of SW1088 and SW1783 cells both in vitro and in vivo, it can also be inhibited to increase the TMZ therapy sensitivity in vivo. These results revealed that TMX1 acts as a strong prognostic biomarker in LGGs, and targeting TMX1 can be an efficient way to increase the TMZ therapy in LGG patients.