Inflammatory Conditions Promote Resistance to Immune Checkpoint Inhibitors in High Microsatellite Instability Colorectal Cancer
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ABSTRACT: Inflammatory conditions caused by obstruction or perforation are common complications in colorectal cancer (CRC) and play important roles in tumor progression and immunosuppression. However, the significance of inflammatory conditions in the tumor response to immune checkpoint inhibitors (ICIs) remains unclear. We found a high microsatellite instability (MSI-H) CRC patient (Patient 1) whose primary tumor progressed and liver metastasis regressed during PD-1 blockade after having inflammatory conditions. Then, in 73 MSI-H CRCs, inflammatory conditions during ICI treatment were correlated with a poor tumor response, and an elevated NLR was associated with a poor immune status and resistance to ICIs. An organoid-T cell coculture model demonstrated an inhibited local immune response to treatment instead of systemic immunosuppression in Patient 1. Single-cell RNA sequencing suggested that neutrophils suppress the immune microenvironment mostly through CTLA-4-associated pathways. Therefore, inflammatory conditions in MSI-H CRCs correlate with resistance to ICIs through neutrophil-associated immunosuppression. Additional CTLA-4 blockade may improve the sensitivity to PD-1 blockade.
ORGANISM(S): Homo sapiens
PROVIDER: GSE179784 | GEO | 2021/07/09
REPOSITORIES: GEO
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