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Ageing Res Rev. 2017 Jul;36:105-116. doi: 10.1016/j.arr.2017.03.008. Epub 2017 Apr 6.

Aging and cancer: The role of macrophages and neutrophils.

Author information

1
School of Biomedical Sciences, Curtin Health and Innovation Research Institute, Faculty of Health Sciences, Curtin University, Bentley, Western Australia, 6102, Australia. Electronic address: connie.jackaman@curtin.edu.au.
2
School of Biomedical Sciences, Curtin Health and Innovation Research Institute, Faculty of Health Sciences, Curtin University, Bentley, Western Australia, 6102, Australia.
3
School of Medicine and Pharmacology, University of Western Australia, Nedlands, Western Australia, 6009, Australia.

Abstract

Impaired immune function has been implicated in the declining health and higher incidence of cancer in the elderly. However, age-related changes to immunity are not completely understood. Neutrophils and macrophages represent the first line of defence yet their ability to phagocytose pathogens decrease with aging. Cytotoxic T lymphocytes are critical in eliminating tumors, but T cell function is also compromised with aging. T cell responses can be regulated by macrophages and may depend on the functional phenotype macrophages adopt in response to microenvironmental signals. This can range from pro-inflammatory, anti-tumorigenic M1 to anti-inflammatory, pro-tumorigenic M2 macrophages. Macrophages in healthy elderly adipose and hepatic tissue exhibit a more pro-inflammatory M1 phenotype compared to young hosts whilst immunosuppressive M2 macrophages increase in elderly lymphoid tissues, lung and muscle. These M2-like macrophages demonstrate altered responses to stimuli. Recent studies suggest that neutrophils also regulate T cell function and, like macrophages, neutrophil function is modulated with aging. It is possible that age-modified tissue-specific macrophages and neutrophils contribute to chronic low-grade inflammation that is associated with dysregulated macrophage-mediated immunosuppression, which together are responsible for development of multiple pathologies, including cancer. This review discusses recent advances in macrophage and neutrophil biology in healthy aging and cancer.

KEYWORDS:

Aging; Cancer; Macrophage; Neutrophil; Tumor microenvironment

PMID:
28390891
DOI:
10.1016/j.arr.2017.03.008
[Indexed for MEDLINE]

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