Peritoneal resident macrophages constitute an immunosuppressive environment in peritoneal metastasized colorectal cancer
Abstract Patients with peritoneal metastasized colorectal cancer (PM-CRC) have a dismal prognosis. We hypothesized that an immunosuppressive environment in the peritoneal cavity underlies poor prognosis. We define the composition of the human peritoneal immune system (PerIS) using single-cell techno...
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| Main Authors: | , , , , , , , , , , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Nature Portfolio
2025-04-01
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| Series: | Nature Communications |
| Online Access: | https://doi.org/10.1038/s41467-025-58999-6 |
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| Summary: | Abstract Patients with peritoneal metastasized colorectal cancer (PM-CRC) have a dismal prognosis. We hypothesized that an immunosuppressive environment in the peritoneal cavity underlies poor prognosis. We define the composition of the human peritoneal immune system (PerIS) using single-cell technologies in 18 patients with- and without PM-CRC, as well as in matched peritoneal metastases (n = 8). Here we show that the PerIS contains abundant immunosuppressive C1Q + VSIG4 + and SPP1 + VSIG4 + peritoneal-resident macrophages (PRMs), as well as monocyte-like cavity macrophages (mono-CMs), which share features with tumor-associated macrophages, even in homeostasis. In PM-CRC, expression of immunosuppressive cytokines IL10 and VEGF increases, while simultaneously expression of antigen-presenting molecules decreases in PRMs. These intratumoral suppressive PRMs originate from the PerIS, and intraperitoneal depletion of PRMs in vivo using anti-CSF1R combined with anti-PD1 significantly reduces tumor burden and improves survival. Thus, PRMs define a metastatic site-specific immunosuppressive niche, and targeting PRMs is a promising treatment strategy for PM-CRC. |
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| ISSN: | 2041-1723 |