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Sun X, Bernhardt SM, Glynn DJ, Hodson LJ, Woolford L, Evdokiou A, Yan C, Du H, Robertson SA, Ingman WV. Attenuated TGFB signalling in macrophages decreases susceptibility to DMBA-induced mammary cancer in mice. Breast Cancer Res 2021; 23:39. [PMID: 33761981 PMCID: PMC7992865 DOI: 10.1186/s13058-021-01417-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 03/10/2021] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Transforming growth factor beta1 (TGFB1) is a multi-functional cytokine that regulates mammary gland development and cancer progression through endocrine, paracrine and autocrine mechanisms. TGFB1 also plays roles in tumour development and progression, and its increased expression is associated with an increased breast cancer risk. Macrophages are key target cells for TGFB1 action, also playing crucial roles in tumourigenesis. However, the precise role of TGFB-regulated macrophages in the mammary gland is unclear. This study investigated the effect of attenuated TGFB signalling in macrophages on mammary gland development and mammary cancer susceptibility in mice. METHODS A transgenic mouse model was generated, wherein a dominant negative TGFB receptor is activated in macrophages, in turn attenuating the TGFB signalling pathway specifically in the macrophage population. The mammary glands were assessed for morphological changes through wholemount and H&E analysis, and the abundance and phenotype of macrophages were analysed through immunohistochemistry. Another cohort of mice received carcinogen 7,12-dimethylbenz(a)anthracene (DMBA), and tumour development was monitored weekly. Human non-neoplastic breast tissue was also immunohistochemically assessed for latent TGFB1 and macrophage marker CD68. RESULTS Attenuation of TGFB signalling resulted in an increase in the percentage of alveolar epithelium in the mammary gland at dioestrus and an increase in macrophage abundance. The phenotype of macrophages was also altered, with inflammatory macrophage markers iNOS and CCR7 increased by 110% and 40%, respectively. A significant decrease in DMBA-induced mammary tumour incidence and prolonged tumour-free survival in mice with attenuated TGFB signalling were observed. In human non-neoplastic breast tissue, there was a significant inverse relationship between latent TGFB1 protein and CD68-positive macrophages. CONCLUSIONS TGFB acts on macrophage populations in the mammary gland to reduce their abundance and dampen the inflammatory phenotype. TGFB signalling in macrophages increases mammary cancer susceptibility potentially through suppression of immune surveillance activities of macrophages.
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MESH Headings
- 9,10-Dimethyl-1,2-benzanthracene/adverse effects
- Animals
- Disease Susceptibility
- Disease-Free Survival
- Epithelial Cells/metabolism
- Estrous Cycle
- Female
- Humans
- Inflammation
- Macrophages/metabolism
- Mammary Glands, Animal/growth & development
- Mammary Glands, Animal/metabolism
- Mammary Glands, Animal/pathology
- Mammary Glands, Human/growth & development
- Mammary Glands, Human/metabolism
- Mammary Glands, Human/pathology
- Mammary Neoplasms, Experimental/chemically induced
- Mammary Neoplasms, Experimental/metabolism
- Mammary Neoplasms, Experimental/pathology
- Mice
- Mice, Transgenic
- Receptor, Transforming Growth Factor-beta Type I/genetics
- Receptor, Transforming Growth Factor-beta Type I/metabolism
- Signal Transduction
- Smad2 Protein/metabolism
- Transforming Growth Factor beta1/metabolism
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Affiliation(s)
- Xuan Sun
- Discipline of Surgery, Adelaide Medical School, The Queen Elizabeth Hospital, University of Adelaide, Adelaide, Australia
- Robinson Research Institute, University of Adelaide, Adelaide, Australia
| | - Sarah M Bernhardt
- Discipline of Surgery, Adelaide Medical School, The Queen Elizabeth Hospital, University of Adelaide, Adelaide, Australia
- Robinson Research Institute, University of Adelaide, Adelaide, Australia
| | - Danielle J Glynn
- Discipline of Surgery, Adelaide Medical School, The Queen Elizabeth Hospital, University of Adelaide, Adelaide, Australia
- Robinson Research Institute, University of Adelaide, Adelaide, Australia
| | - Leigh J Hodson
- Discipline of Surgery, Adelaide Medical School, The Queen Elizabeth Hospital, University of Adelaide, Adelaide, Australia
- Robinson Research Institute, University of Adelaide, Adelaide, Australia
| | - Lucy Woolford
- School of Animal and Veterinary Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Andreas Evdokiou
- Discipline of Surgery, Adelaide Medical School, The Queen Elizabeth Hospital, University of Adelaide, Adelaide, Australia
| | - Cong Yan
- Department of Pathology and Laboratory Medicine, Indiana University, Indianapolis, IN, USA
| | - Hong Du
- Department of Pathology and Laboratory Medicine, Indiana University, Indianapolis, IN, USA
| | - Sarah A Robertson
- Robinson Research Institute, University of Adelaide, Adelaide, Australia
- Adelaide Medical School, University of Adelaide, Adelaide, Australia
| | - Wendy V Ingman
- Discipline of Surgery, Adelaide Medical School, The Queen Elizabeth Hospital, University of Adelaide, Adelaide, Australia.
- Robinson Research Institute, University of Adelaide, Adelaide, Australia.
- Discipline of Surgery, The Queen Elizabeth Hospital, DX465702, 28 Woodville Rd., Woodville, 5011, Australia.
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