N-glycans in non-malignant tumor microenvironment cells dampen CAR-T cell function in solid tumors

Area of Science:

• Immunology
• Glycobiology
• Cancer Biology

Background:

• CAR T-cell therapy shows limited success in solid tumors due to the immunosuppressive tumor microenvironment (TME).
• The role of N-glycans on non-malignant TME cells in CAR-T cell dysfunction is not well understood.

Purpose of the Study:

• To investigate the impact of N-glycans on non-malignant cells within the TME on CAR-T cell function.
• To explore the potential of targeting N-glycosylation pathways to enhance CAR-T cell efficacy in colorectal cancer (CRC) and pancreatic ductal adenocarcinoma (PDAC).

Main Methods:

• Utilized in vitro co-culture systems, transcriptomic analysis, and humanized mouse models.
• Investigated the effects of pharmacologic or genetic disruption of N-glycosylation pathway genes (MGAT5, MAN2A1, ST6GAL1) in immune and stromal cells.
• Employed single-cell RNA sequencing to analyze TME changes and CAR-T cell activity.

Main Results:

• A branched N-glycan signature in patient samples correlated with immunosuppressive TME cell transcriptional programs.
• Disrupting N-glycan synthesis in non-malignant TME cells reduced immunosuppression and tumor support.
• MGAT5 disruption in immune and stromal cells enhanced CAR-T cell antitumor activity, independent of tumor cell glycosylation.

Conclusions:

• N-glycans on non-malignant TME cells significantly restrain CAR-T cell responses in CRC and PDAC.
• MGAT5-dependent N-glycan branching represents a potential therapeutic target.
• The N-glycosylation pathway offers a broader target for improving CAR-T cell therapy in solid tumors.