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Updated: Aug 11, 2025
Isolation and Characterization of Neutrophils with Anti-Tumor Properties
Published on: June 19, 2015
Natural killer cells suppress cancer metastasis by eliminating circulating cancer cells
Maulik Vyas1, Marta Requesens1, Thao H Nguyen1
1Department of Dermatology and Center for Cancer Research, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States.
Abstract:
Despite significant advances in cancer treatment, the metastatic spread of malignant cells to distant organs remains a major cause of cancer-related deaths. Natural killer (NK) cells play a crucial role in controlling tumor metastasis; however, the dynamics of NK cell-mediated clearance of metastatic tumors are not entirely understood. Herein, we demonstrate the cooperative role of NK and T cells in the surveillance of melanoma metastasis. We found that NK cells effectively limited the pulmonary seeding of B16 melanoma cells, while T cells played a primary role in restricting metastatic foci growth in the lungs. Although the metastatic foci in the lungs at the endpoint were largely devoid of NK cells, they played a prominent role in promoting T cell recruitment into the metastatic foci. Our data suggested that the most productive interaction between NK cells and metastatic cancer cells occurred when cancer cells were in circulation. Modifying the route of administration so that intravenously injected melanoma cells bypass the first liver passage resulted in significantly more melanoma metastasis to the lung. This finding indicated the liver as a prominent site where NK cells cleared melanoma cells to regulate their seeding in the lungs. Consistent with this notion, the liver and the lungs of the tumor-bearing mice showed dominance of NK and T cell activation, respectively. Thus, NK cells and T cells control pulmonary metastasis of melanoma cells by distinct mechanisms where NK cells play a critical function in shaping T cell-mediated in situ control of lung-seeded cancer cells. A precise understanding of the cooperative role of NK and T cells in controlling tumor metastasis will enable the development of the next generation of cancer immunotherapies.
Insights
Natural killer (NK) cells and T cells cooperate to combat melanoma metastasis. NK cells target circulating cancer cells, primarily in the liver, while T cells eliminate established lung tumors, highlighting a dual-action immunotherapy strategy.
Area of Science:
- Immunology
- Oncology
- Cancer Metastasis Research
Background:
- Metastatic spread is a leading cause of cancer mortality.
- Natural killer (NK) cells are vital in controlling tumor metastasis, but their precise role is unclear.
- Understanding immune cell dynamics in metastasis is crucial for developing effective cancer therapies.
Purpose of the Study:
- To elucidate the cooperative roles of NK cells and T cells in melanoma metastasis surveillance.
- To investigate the mechanisms by which NK cells and T cells control tumor spread.
- To identify key sites and interactions for immune-mediated control of metastatic disease.
Main Methods:
- Utilized B16 melanoma models in mice to study metastasis.
- Investigated the impact of altered administration routes on metastatic seeding.
- Analyzed NK and T cell activation and infiltration in the liver and lungs.
- Examined the dynamics of immune cell interactions with circulating and established tumor cells.
Main Results:
- NK cells limited pulmonary seeding of melanoma cells, particularly in the liver.
- T cells were critical for restricting the growth of established lung metastatic foci.
- NK cells promoted T cell recruitment into metastatic sites.
- Bypassing liver passage of melanoma cells significantly increased lung metastasis.
- Liver and lung tissues showed distinct patterns of NK and T cell activation, respectively.
Conclusions:
- NK cells and T cells exert distinct but cooperative functions in controlling melanoma pulmonary metastasis.
- NK cells act early by clearing circulating tumor cells, primarily in the liver, shaping subsequent T cell responses.
- T cells are essential for the in situ control of lung-seeded cancer cells.
- This study provides insights into immune surveillance mechanisms against metastasis, informing future immunotherapy development.
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