Metabolic reprogramming through PIM3 inhibition reverses hypoxia-induced CAR-T cell dysfunction in solid tumors.

Area of Science:

• Immunotherapy
• Cancer Biology
• Cellular Metabolism

Background:

• Chimeric antigen receptor (CAR)-T cell therapy is effective in blood cancers but limited in solid tumors.
• The immunosuppressive tumor microenvironment (TME), particularly hypoxia, hinders CAR-T cell efficacy.
• Molecular mechanisms linking hypoxia to CAR-T cell dysfunction are not fully understood.

Purpose of the Study:

• To investigate the impact of hypoxia on CAR-T cell function.
• To identify molecular mediators of hypoxia-induced CAR-T cell dysfunction.
• To evaluate PIM3 inhibition as a strategy to overcome hypoxia-driven impairment.

Main Methods:

• Cultured anti-MSLN CAR-T cells under normoxic and hypoxic conditions.
• Assessed CAR-T cell proliferation, phenotype, cytotoxicity, and metabolism.
• Utilized RNA sequencing to identify hypoxia-induced gene expression changes.
• Validated findings with anti-CD70 CAR-T cells and PIM3 inhibition.

Main Results:

• Hypoxia reduced CAR-T cell proliferation, increased apoptosis, and impaired cytotoxicity.
• Transcriptomic and metabolic analyses revealed increased glycolysis and reduced oxidative phosphorylation.
• PIM3 was identified as a key mediator of hypoxia-induced CAR-T cell dysfunction.
• PIM3 inhibition enhanced CAR-T cell memory phenotypes and anti-tumor activity in vitro and in vivo.

Conclusions:

• PIM3 is a novel target linking hypoxia to CAR-T cell dysfunction in solid tumors.
• PIM3 inhibition can reverse hypoxia-induced impairment of CAR-T cell function.
• Targeting PIM3 offers a promising strategy to enhance CAR-T cell therapy for hypoxic solid tumors.