The Impact of the Tumor Microenvironment on Macrophage Polarization in Cancer Metastatic Progression
Rather than primary solid tumors, metastasis is one of the hallmarks of most cancer deaths. Metastasis is a multistage event in which cancer cells escape from the primary tumor survive in the circulation and disseminate to distant sites. According to Stephen Paget’s “Seed and Soil” hypothesis, metas...
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MDPI AG
2021-06-01
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| Series: | International Journal of Molecular Sciences |
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| Online Access: | https://www.mdpi.com/1422-0067/22/12/6560 |
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| author | Huogang Wang Mingo M. H. Yung Hextan Y. S. Ngan Karen K. L. Chan David W. Chan |
| author_facet | Huogang Wang Mingo M. H. Yung Hextan Y. S. Ngan Karen K. L. Chan David W. Chan |
| author_sort | Huogang Wang |
| collection | DOAJ |
| description | Rather than primary solid tumors, metastasis is one of the hallmarks of most cancer deaths. Metastasis is a multistage event in which cancer cells escape from the primary tumor survive in the circulation and disseminate to distant sites. According to Stephen Paget’s “Seed and Soil” hypothesis, metastatic capacity is determined not only by the internal oncogenic driving force but also by the external environment of tumor cells. Throughout the body, macrophages are required for maintaining tissue homeostasis, even in the tumor milieu. To fulfill these multiple functions, macrophages are polarized from the inflammation status (M1-like) to anti-inflammation status (M2-like) to maintain the balance between inflammation and regeneration. However, tumor cell-enforced tumor-associated macrophages (TAMs) (a high M2/M1 ratio status) are associated with poor prognosis for most solid tumors, such as ovarian cancer. In fact, clinical evidence has verified that TAMs, representing up to 50% of the tumor mass, exert both protumor and immunosuppressive effects in promoting tumor metastasis through secretion of interleukin 10 (IL10), transforming growth factor β (TGFβ), and VEGF, expression of PD-1 and consumption of arginine to inhibit T cell anti-tumor function. However, the underlying molecular mechanisms by which the tumor microenvironment favors reprogramming of macrophages to TAMs to establish a premetastatic niche remain controversial. In this review, we examine the latest investigations of TAMs during tumor development, the microenvironmental factors involved in macrophage polarization, and the mechanisms of TAM-mediated tumor metastasis. We hope to dissect the critical roles of TAMs in tumor metastasis, and the potential applications of TAM-targeted therapeutic strategies in cancer treatment are discussed. |
| first_indexed | 2024-03-10T10:18:00Z |
| format | Article |
| id | doaj.art-d8d296bf4fee4c6e91f375b8c290a15f |
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| issn | 1661-6596 1422-0067 |
| language | English |
| last_indexed | 2024-03-10T10:18:00Z |
| publishDate | 2021-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | International Journal of Molecular Sciences |
| spelling | doaj.art-d8d296bf4fee4c6e91f375b8c290a15f2023-11-22T00:43:51ZengMDPI AGInternational Journal of Molecular Sciences1661-65961422-00672021-06-012212656010.3390/ijms22126560The Impact of the Tumor Microenvironment on Macrophage Polarization in Cancer Metastatic ProgressionHuogang Wang0Mingo M. H. Yung1Hextan Y. S. Ngan2Karen K. L. Chan3David W. Chan4Department of Obstetrics & Gynaecology, LKS Faculty of Medicine, University of Hong Kong, Hong Kong, ChinaDepartment of Obstetrics & Gynaecology, LKS Faculty of Medicine, University of Hong Kong, Hong Kong, ChinaDepartment of Obstetrics & Gynaecology, LKS Faculty of Medicine, University of Hong Kong, Hong Kong, ChinaDepartment of Obstetrics & Gynaecology, LKS Faculty of Medicine, University of Hong Kong, Hong Kong, ChinaDepartment of Obstetrics & Gynaecology, LKS Faculty of Medicine, University of Hong Kong, Hong Kong, ChinaRather than primary solid tumors, metastasis is one of the hallmarks of most cancer deaths. Metastasis is a multistage event in which cancer cells escape from the primary tumor survive in the circulation and disseminate to distant sites. According to Stephen Paget’s “Seed and Soil” hypothesis, metastatic capacity is determined not only by the internal oncogenic driving force but also by the external environment of tumor cells. Throughout the body, macrophages are required for maintaining tissue homeostasis, even in the tumor milieu. To fulfill these multiple functions, macrophages are polarized from the inflammation status (M1-like) to anti-inflammation status (M2-like) to maintain the balance between inflammation and regeneration. However, tumor cell-enforced tumor-associated macrophages (TAMs) (a high M2/M1 ratio status) are associated with poor prognosis for most solid tumors, such as ovarian cancer. In fact, clinical evidence has verified that TAMs, representing up to 50% of the tumor mass, exert both protumor and immunosuppressive effects in promoting tumor metastasis through secretion of interleukin 10 (IL10), transforming growth factor β (TGFβ), and VEGF, expression of PD-1 and consumption of arginine to inhibit T cell anti-tumor function. However, the underlying molecular mechanisms by which the tumor microenvironment favors reprogramming of macrophages to TAMs to establish a premetastatic niche remain controversial. In this review, we examine the latest investigations of TAMs during tumor development, the microenvironmental factors involved in macrophage polarization, and the mechanisms of TAM-mediated tumor metastasis. We hope to dissect the critical roles of TAMs in tumor metastasis, and the potential applications of TAM-targeted therapeutic strategies in cancer treatment are discussed.https://www.mdpi.com/1422-0067/22/12/6560tumor microenvironmentmacrophage polarizationperitoneal metastasistumor-associated macrophagespremetastatic niche |
| spellingShingle | Huogang Wang Mingo M. H. Yung Hextan Y. S. Ngan Karen K. L. Chan David W. Chan The Impact of the Tumor Microenvironment on Macrophage Polarization in Cancer Metastatic Progression International Journal of Molecular Sciences tumor microenvironment macrophage polarization peritoneal metastasis tumor-associated macrophages premetastatic niche |
| title | The Impact of the Tumor Microenvironment on Macrophage Polarization in Cancer Metastatic Progression |
| title_full | The Impact of the Tumor Microenvironment on Macrophage Polarization in Cancer Metastatic Progression |
| title_fullStr | The Impact of the Tumor Microenvironment on Macrophage Polarization in Cancer Metastatic Progression |
| title_full_unstemmed | The Impact of the Tumor Microenvironment on Macrophage Polarization in Cancer Metastatic Progression |
| title_short | The Impact of the Tumor Microenvironment on Macrophage Polarization in Cancer Metastatic Progression |
| title_sort | impact of the tumor microenvironment on macrophage polarization in cancer metastatic progression |
| topic | tumor microenvironment macrophage polarization peritoneal metastasis tumor-associated macrophages premetastatic niche |
| url | https://www.mdpi.com/1422-0067/22/12/6560 |
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