Objective:

To explore metabolic competition in the glioblastoma microenvironment and its implications for immune exclusion and pharmacological interventions.

Approach:

• Metabolic Cell Competition: The review discusses how differential metabolic fitness, particularly through glucose and glutamine consumption, establishes a suppressive hierarchy in the glioblastoma tumor microenvironment.
• Pharmacological Interventions: Various pharmacological strategies are reviewed, including glutamine antagonism, dichloroacetate, and pharmacological ketosis, aimed at disrupting metabolic competition to enhance T cell function.

Key Findings:

• Aerobic glycolysis in GBM cells produces lactate, polarizing tumor-associated macrophages towards immunosuppressive phenotypes.
• GBM cells and immunosuppressive myeloid cells rely on glucose and glutamine for their functions, while cytotoxic T cells can utilize fatty acid oxidation under substrate restriction.
• Disrupting glucose and glutamine metabolism can reprogram the immunosuppressive myeloid compartment while preserving T cell fitness.

Interpretation:

The glioblastoma TME is characterized by a competitive metabolic landscape where GBM and myeloid cells compete with T cells for essential nutrients, leading to immune exclusion.

Limitations:

• The review synthesizes evidence from various studies but does not provide extensive clinical trial data for all proposed interventions.
• Research gaps in understanding the complete metabolic interactions within the TME are acknowledged.

Conclusion:

The review proposes that simultaneous disruption of GBM cells and immunosuppressive myeloid cells may be a therapeutic strategy.