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PloS One 2016Breast cancer, the product of numerous rare mutational events that occur over an extended time period, presents numerous challenges to investigators interested in...
INTRODUCTION
Breast cancer, the product of numerous rare mutational events that occur over an extended time period, presents numerous challenges to investigators interested in studying the transformation from normal breast epithelium to malignancy using traditional laboratory methods, particularly with respect to characterizing transitional and pre-malignant states. Dynamic computational modeling can provide insight into these pathophysiological dynamics, and as such we use a previously validated agent-based computational model of the mammary epithelium (the DEABM) to investigate the probabilistic mechanisms by which normal populations of ductal cells could transform into states replicating features of both pre-malignant breast lesions and a diverse set of breast cancer subtypes.
METHODS
The DEABM consists of simulated cellular populations governed by algorithms based on accepted and previously published cellular mechanisms. Cells respond to hormones, undergo mitosis, apoptosis and cellular differentiation. Heritable mutations to 12 genes prominently implicated in breast cancer are acquired via a probabilistic mechanism. 3000 simulations of the 40-year period of menstrual cycling were run in wild-type (WT) and BRCA1-mutated groups. Simulations were analyzed by development of hyperplastic states, incidence of malignancy, hormone receptor and HER-2 status, frequency of mutation to particular genes, and whether mutations were early events in carcinogenesis.
RESULTS
Cancer incidence in WT (2.6%) and BRCA1-mutated (45.9%) populations closely matched published epidemiologic rates. Hormone receptor expression profiles in both WT and BRCA groups also closely matched epidemiologic data. Hyperplastic populations carried more mutations than normal populations and mutations were similar to early mutations found in ER+ tumors (telomerase, E-cadherin, TGFB, RUNX3, p < .01). ER- tumors carried significantly more mutations and carried more early mutations in BRCA1, c-MYC and genes associated with epithelial-mesenchymal transition.
CONCLUSIONS
The DEABM generates diverse tumors that express tumor markers consistent with epidemiologic data. The DEABM also generates non-invasive, hyperplastic populations, analogous to atypia or ductal carcinoma in situ (DCIS), via mutations to genes known to be present in hyperplastic lesions and as early mutations in breast cancers. The results demonstrate that agent-based models are well-suited to studying tumor evolution through stages of carcinogenesis and have the potential to be used to develop prevention and treatment strategies.
Topics: Breast Neoplasms; Carcinogenesis; Cell Lineage; DNA Damage; DNA Repair; Epithelium; Female; Humans; Hyperplasia; Incidence; Mammary Glands, Human; Mutation; Receptors, Estrogen; Signal Transduction; Systems Analysis
PubMed: 27023391
DOI: 10.1371/journal.pone.0152298 -
Breast Cancer Research : BCR Mar 2021Transforming growth factor beta1 (TGFB1) is a multi-functional cytokine that regulates mammary gland development and cancer progression through endocrine, paracrine and...
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.
Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Disease Susceptibility; Disease-Free Survival; Epithelial Cells; Estrous Cycle; Female; Humans; Inflammation; Macrophages; Mammary Glands, Animal; Mammary Glands, Human; Mammary Neoplasms, Experimental; Mice; Mice, Transgenic; Receptor, Transforming Growth Factor-beta Type I; Signal Transduction; Smad2 Protein; Transforming Growth Factor beta1
PubMed: 33761981
DOI: 10.1186/s13058-021-01417-8 -
Journal of Mammary Gland Biology and... Jul 2005The human breast epithelium is a branching ductal system composed of an inner layer of polarized luminal epithelial cells and an outer layer of myoepithelial cells that... (Review)
Review
The human breast epithelium is a branching ductal system composed of an inner layer of polarized luminal epithelial cells and an outer layer of myoepithelial cells that terminate in distally located terminal duct lobular units (TDLUs). While the luminal epithelial cell has received the most attention as the functionally active milk-producing cell and as the most likely target cell for carcinogenesis, attention on myoepithelial cells has begun to evolve with the recognition that these cells play an active part in branching morphogenesis and tumor suppression. A major question that has been the subject of investigation pertains to how the luminal epithelial and myoepithelial lineages are related and precisely how they arise from a common putative stem cell population within the breast. Equally important is the question of how heterotypic signaling occurs between luminal epithelial and surrounding myoepithelial cells in normal breast morphogenesis and neoplasia. In this review we discuss data from our laboratories and from others regarding the cellular origin of human myoepithelial cells, their function in maintaining tissue polarity in the normal breast, and their role during neoplasia.
Topics: Animals; Biomarkers, Tumor; Breast Neoplasms; Cell Differentiation; Cell Lineage; Cell Polarity; Cell Transformation, Neoplastic; Epithelial Cells; Female; Humans; Mammary Glands, Human; Morphogenesis; Stem Cells
PubMed: 16807805
DOI: 10.1007/s10911-005-9586-4 -
Cell Proliferation Oct 2003Breast epithelial stem cells are thought to be the primary targets in the aetiology of breast cancer. As breast cancers are predominantly oestrogen and progesterone... (Review)
Review
Breast epithelial stem cells are thought to be the primary targets in the aetiology of breast cancer. As breast cancers are predominantly oestrogen and progesterone receptor-positive (ERalpha/PR+), we investigated the biology of ERalpha/PR+ cells and their relationship to stem cells in normal human breast epithelium. Several complementary approaches were used to characterize the stem-cell population and relate it to ERalpha/PR+ cells, including dual label colocalization on tissue sections, isolation of a Hoechst dye-effluxing 'side population' using flow cytometry, and examination of DNA label retention. The intermediate or suprabasal population suggested by others to be breast stem cells comprises ERalpha/PR+ cells that coexpress the putative stem-cell markers including cytokeratin 19. Human breast epithelial cells with Hoechst dye-effluxing 'side population' properties characteristic of mammary stem cells in mice were demonstrated by lack of expression of myoepithelial and luminal cell-specific antigens such as CALLA and MUC1 to be undifferentiated cells. Using DNA radiolabelling of human tissue implanted into athymic nude mice, a population of label-retaining putative stem cells (LRC) were shown to be enriched for cells expressing the putative stem-cell markers p21CIP1/WAF1 and Musashi-1, which, interestingly, were expressed in separate subpopulations of ERalpha/PR+ cells. Finally, expression patterns of Musashi-1 and Notch-1 in relation to ERalpha/PR+ and adjacent proliferating cells suggest that the evolutionarily conserved Delta/Notch signalling pathway regulates asymmetric division of the putative stem-cell population. The data suggest a model in which ERalpha/PR+ cells scattered through the epithelium are stem cells that self-renew through asymmetric cell division and generate patches of transit amplifying and differentiated cells. ERalpha/PR+ breast cancers exhibit loss of the two key regulators of asymmetric cell division, Musashi-1 and Notch-1 and thus may arise from symmetric division of the ERalpha/PR+ stem cell.
Topics: Breast; Epithelial Cells; Humans; Stem Cells
PubMed: 14521515
DOI: 10.1046/j.1365-2184.36.s.1.5.x -
British Journal of Cancer Dec 1987The staining pattern of a monoclonal antibody directed to the monomorphic determinant of HLA-DR antigens was examined on sections of human mammary gland tissues at...
The staining pattern of a monoclonal antibody directed to the monomorphic determinant of HLA-DR antigens was examined on sections of human mammary gland tissues at various stages of differentiation as well as on 50 benign and 72 malignant breast lesions. Normal resting breast epithelium lacked HLA-DR, whereas late-pregnant and lactating epithelia expressed high levels of HLA-DR antigens, followed by a decline in the post-weaning regression period. Most benign breast lesions revealed heterogeneous staining ranging from very few up to 20-25% positive epithelial Greater variability was observed among carcinomas, where a small group (approximately 7%) of cases showing 40-95% positive tumour cells was found, in addition to negative tumours and those with the minority of HLA-DR expressing carcinoma cells. The density of the leukocytic infiltrate was higher in carcinomas than in either normal breast tissue or benign lesions, the HLA-DR phenotype of the mononuclear infiltrating cells lacking any obvious correlation with the HLA-DR status of the epithelial component. Immunoblotting analyses of whole-tissue lysates separated by SDS-PAGE confirmed the immunohistochemical data and demonstrated the reactivity with only one protein band predicted for HLA-DR alpha-chain. The combination of immunohistochemistry and autoradiography on sections of human reduction mammoplasty organoids cultured in collagen gels and labelled with tritiated thymidine revealed a lack of HLA-DR expression on proliferating breast epithelial cells suggesting factors other than cell kinetics must be responsible for induction of HLA-DR antigens seen in pregnant and lactating breast epithelium and some tumours.
Topics: Antibodies, Monoclonal; Breast; Breast Neoplasms; Cell Differentiation; Cell Transformation, Neoplastic; Epithelium; Female; HLA-D Antigens; HLA-DR Antigens; Humans; Lactation; Leukocytes; Male; Mitosis; Pregnancy
PubMed: 3435699
DOI: 10.1038/bjc.1987.278 -
Methods in Molecular Biology (Clifton,... 2016The need for model systems that more accurately predict patient outcome has led to a renewed interest and a rapid development of orthotopic transplantation models...
The need for model systems that more accurately predict patient outcome has led to a renewed interest and a rapid development of orthotopic transplantation models designed to grow, expand, and study patient-derived human breast tumor tissue in mice. After implanting a human breast tumor piece into a mouse mammary fat pad and allowing the tumor to grow in vivo, the tumor tissue can be either harvested and immediately implanted into mice or can be stored as tissue pieces in liquid nitrogen for surgical implantation at a later time. Here, we describe the process of surgically implanting patient-derived breast tumor tissue into the mammary gland of nonobese diabetic-severe combined immunodeficiency (NOD-SCID) mice and harvesting tumor tissue for long-term storage in liquid nitrogen.
Topics: Adipose Tissue; Animals; Breast Neoplasms; Cell Transformation, Neoplastic; Cryopreservation; Disease Models, Animal; Epithelium; Estrogens; Humans; Mammary Glands, Human; Mice; Mice, Inbred NOD; Nitrogen
PubMed: 26820959
DOI: 10.1007/978-1-4939-3444-7_19 -
Breast Cancer Research : BCR Nov 2014For many decades, developmental biologists and cancer researchers alike have been trying to understand the relationship between the basal and luminal cell compartments...
For many decades, developmental biologists and cancer researchers alike have been trying to understand the relationship between the basal and luminal cell compartments in the mouse mammary epithelium. Delineating the mammary stem and progenitor cell hierarchy will provide fundamental knowledge of how cell proliferation and differentiation are orchestrated to build, maintain and regenerate a complex mammalian tissue. Moreover, it is expected to offer insight into the cells of origin for human breast cancer. A new lineage-tracing study has fuelled the discussion as to the existence of bipotent stem cells in the basal layer of the mouse mammary epithelium.
Topics: Animals; Female; Humans; Mammary Glands, Animal; Mammary Glands, Human; Multipotent Stem Cells
PubMed: 25927976
DOI: 10.1186/s13058-014-0480-0 -
Breast Cancer Research : BCR 2006Involution of the mammary gland is an essential process that removes the milk-producing epithelial cells when they become redundant at weaning. It is a two-step process... (Review)
Review
Involution of the mammary gland is an essential process that removes the milk-producing epithelial cells when they become redundant at weaning. It is a two-step process that involves the death of the secretory epithelium and its replacement by adipocytes. During the first phase, remodelling is inhibited and apoptotic cells can be seen in the lumena of the alveoli. In the second phase, apoptosis is accompanied by remodelling of the surrounding stroma and re-differentiation of the adipocytes. Considerable effort has been directed towards understanding the molecular mechanisms of the involution process and this has resulted in the identification of the principal signalling pathways involved.
Topics: Apoptosis; Breast; Cell Death; Female; Humans; Lactation; Milk, Human
PubMed: 16677411
DOI: 10.1186/bcr1401 -
Journal of Biomedicine & Biotechnology 2011The interactions between breast epithelium and stroma are fundamental to normal tissue homeostasis and for tumor initiation and progression. Gene expression studies of... (Review)
Review
The interactions between breast epithelium and stroma are fundamental to normal tissue homeostasis and for tumor initiation and progression. Gene expression studies of in vitro coculture models demonstrate that in vitro models have relevance for tumor progression in vivo. For example, stromal gene expression has been shown to vary in association with tumor subtype in vivo, and analogous in vitro cocultures recapitulate subtype-specific biological interactions. Cocultures can be used to study cancer cell interactions with specific stromal components (e.g., immune cells, fibroblasts, endothelium) and different representative cell lines (e.g., cancer-associated versus normal-associated fibroblasts versus established, immortalized fibroblasts) can help elucidate the role of stromal variation in tumor phenotypes. Gene expression data can also be combined with cell-based assays to identify cellular phenotypes associated with gene expression changes. Coculture systems are manipulable systems that can yield important insights about cell-cell interactions and the cellular phenotypes that occur as tumor and stroma co-evolve.
Topics: Breast; Breast Neoplasms; Cell Communication; Cell Culture Techniques; Coculture Techniques; Endothelium; Epithelial Cells; Epithelium; Female; Fibroblasts; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Humans; Models, Animal; Phenotype; Stromal Cells; Tumor Microenvironment
PubMed: 22203785
DOI: 10.1155/2011/520987 -
PloS One 2020There has been significant concern regarding fertility and reproductive outcomes during the SARS-CoV2 pandemic. Recent data suggests a high concentration of SARS-Cov2...
There has been significant concern regarding fertility and reproductive outcomes during the SARS-CoV2 pandemic. Recent data suggests a high concentration of SARS-Cov2 receptors, ACE2 or TMPRSS2, in nasal epithelium and cornea, which explains person-to-person transmission. We investigated the prevalence of SARS-CoV2 receptors among reproductive tissues by exploring the single-cell sequencing datasets from uterus, myometrium, ovary, fallopian tube, and breast epithelium. We did not detect significant expression of either ACE2 or TMPRSS2 in the normal human myometrium, uterus, ovaries, fallopian tube, or breast. Furthermore, none of the cell types in the female reproductive organs we investigated, showed the co-expression of ACE2 with proteases, TMPRSS2, Cathepsin B (CTSB), and Cathepsin L (CTSL) known to facilitate the entry of SARS2-CoV2 into the host cell. These results suggest that myometrium, uterus, ovaries, fallopian tube, and breast are unlikely to be susceptible to infection by SARS-CoV2.
Topics: Angiotensin-Converting Enzyme 2; Breast; COVID-19; Cathepsin B; Cathepsin L; Epithelium; Fallopian Tubes; Female; Fertility; High-Throughput Nucleotide Sequencing; Humans; Myometrium; Ovary; RNA, Viral; Reproductive Tract Infections; SARS-CoV-2; Serine Endopeptidases; Single-Cell Analysis; Uterus
PubMed: 33315943
DOI: 10.1371/journal.pone.0243959