Suppression of antitumor T cell immunity by the oncometabolite (R)-2-hydroxyglutarate

Area of Science:

• Oncology
• Immunology
• Metabolic pathways

Background:

• Mutations in isocitrate dehydrogenase (IDH) produce the oncometabolite (R)-2-hydroxyglutarate (R-2-HG).
• R-2-HG is known to promote gliomagenesis through epigenetic modifications like DNA and histone methylation.
• The precise impact of R-2-HG on the tumor immune microenvironment remains incompletely understood.

Purpose of the Study:

• To investigate the non-tumor cell-autonomous functions of R-2-HG.
• To determine the effect of R-2-HG on T cell activity and function within the tumor microenvironment.
• To explore therapeutic strategies targeting R-2-HG production or its effects in IDH-mutant gliomas.

Main Methods:

• Analysis of T cell function and transcriptional activity in the presence of R-2-HG.
• Assessment of polyamine biosynthesis and nuclear factor of activated T cells (NFAT) signaling pathways.
• Evaluation of T cell abundance and calcium signaling in IDH1-mutant gliomas.
• Testing the efficacy of inhibiting mutant IDH1's neomorphic enzymatic function in preclinical tumor models.

Main Results:

• Tumor-derived R-2-HG is internalized by T cells, impairing their transcriptional activity and polyamine metabolism.
• This leads to suppressed T cell activity and reduced T cell infiltration in IDH1-mutant gliomas.
• Inhibition of mutant IDH1's neomorphic enzymatic activity enhances anti-tumor immunity.

Conclusions:

• R-2-HG has a novel function in suppressing anti-tumor immunity by directly impacting T cells.
• IDH1-mutant gliomas create an immunosuppressive microenvironment partly through R-2-HG.
• Targeting the neomorphic enzymatic function of mutant IDH1 represents a promising therapeutic avenue for enhancing anti-tumor immunity in gliomas.