The TRIB2-DNMT1 Pathway Generates an Immune-Cold Microenvironment in Glioblastoma, and Its Inhibition Promotes...

Area of Science:

• Neuro-oncology
• Immunology
• Molecular Biology

Background:

• Glioblastoma (GBM) exhibits poor immunotherapy response due to a cold tumor microenvironment (TME) with limited CD8+ T-cell infiltration.
• The mechanisms driving this immune-cold TME in GBM, despite myeloid cell presence and blood-brain barrier alterations, remain unclear.

Purpose of the Study:

• To identify key regulators responsible for the reduced CD8+ T-cell infiltration in the GBM TME.
• To investigate the role of TRIB2 in modulating the GBM immune microenvironment.

Main Methods:

• Transcriptomic screening to identify potential regulators of the GBM immune microenvironment.
• Immunohistochemistry, RNA-sequencing, and quantitative real-time PCR on 114 brain tumors.
• Inhibition of TRIB2 in murine glioma models and analysis of patient-derived tumor fragments.

Main Results:

• TRIB2 was identified as a regulator of the immune-cold TME in GBM.
• TRIB2 was found to inhibit genes for antigen presentation and T-cell recruitment by modulating methylation regulators, notably DNMT1.
• TRIB2 inhibition resulted in 75% survival in murine glioma models, with Decitabine showing transcriptomic reprogramming and generalized response in patient-derived tumor fragments.

Conclusions:

• TRIB2 plays a critical role in establishing an immune-cold TME in GBM by suppressing T-cell infiltration.
• DNMT1 inhibition, potentially through Decitabine, represents a promising therapeutic strategy for GBM by overcoming immune evasion.