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Chen T, Li Q, Wu J, Wu Y, Peng W, Li H, Wang J, Tang X, Peng Y, Fu X. Fusobacterium nucleatum promotes M2 polarization of macrophages in the microenvironment of colorectal tumours via a TLR4-dependent mechanism. Cancer Immunol Immunother 2018; 67:1635-1646. [PMID: 30121899 PMCID: PMC11028377 DOI: 10.1007/s00262-018-2233-x] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 08/09/2018] [Indexed: 12/13/2022]
Abstract
Fusobacterium nucleatum (Fn) has been shown to promote colorectal cancer (CRC) development by inhibiting host anti-tumour immunity. However, the impact of Fn infection on macrophage polarization and subsequent intestinal tumour formation as well as the underlying molecular pathways has not been investigated. We investigated the impact of Fn infection on macrophage polarization in human CRCs and cultured macrophages as well as the effects on macrophage phenotype and intestinal tumour formation in ApcMin/+ mice. We also examined whether macrophage-polarized activation challenged by Fn infection via a TLR4-dependent mechanism involved the IL-6/STAT3/c-MYC signalling cascade. Our data showed that macrophages are a major tumour-infiltrating immune cell type in human CRCs with Fn infection (P < 0.001). Fn infection increased M2 polarization of macrophages in vitro and in vivo, leading to intestinal tumour growth in ApcMin/+ mice. Moreover, Fn infection induced high expression of TLR4, IL-6, STAT3, p-STAT3, and c-MYC in cultured macrophages challenged with Fn, which was blocked by TAK-242 pre-treatment (P < 0.05). Interestingly, c-MYC protein was mainly co-localized with CD206+ M2 macrophages with Fn infection. In conclusion, we show that Fn infection increased M2 polarization of macrophages in vitro and in vivo. Furthermore, Fn infection enhanced colorectal tumour growth in a TLR4-dependent manner involving activation of the IL-6/p-STAT3/c-MYC signalling pathway. For the first time, our results indicate an immunosuppressive effect of Fn by promoting M2 polarization of macrophages through a TLR4-dependent mechanism, which may serve as a promising target for immunotherapy of Fn-related CRC.
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Affiliation(s)
- Ting Chen
- Department of Gastroenterology, The Affiliated Hospital of Chengdu University, Chengdu, 610081, China
| | - Qing Li
- Department of Gastroenterology, The Affiliated Hospital of Southwest Medical University, Sichuan, 646000, China
| | - Jiao Wu
- Department of Gastroenterology, The Affiliated Hospital of Southwest Medical University, Sichuan, 646000, China
| | - Yaxin Wu
- Department of Gastroenterology, The Affiliated Hospital of Southwest Medical University, Sichuan, 646000, China
| | - Wei Peng
- Department of Gastroenterology, The Affiliated Hospital of Southwest Medical University, Sichuan, 646000, China
| | - Huan Li
- Department of Gastroenterology, The Affiliated Hospital of Southwest Medical University, Sichuan, 646000, China
| | - Jianmei Wang
- Department of Pathology, The Affiliated Hospital of Southwest Medical University, Sichuan, 646000, China
| | - Xiaowei Tang
- Department of Gastroenterology, The Affiliated Hospital of Southwest Medical University, Sichuan, 646000, China
| | - Yan Peng
- Department of Gastroenterology, The Affiliated Hospital of Southwest Medical University, Sichuan, 646000, China
| | - Xiangsheng Fu
- Department of Gastroenterology, The Affiliated Hospital of North Sichuan Medical College, Road Wenhua 63#, Region Shunqing, Nanchong, 637000, China.
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