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Shackleton, M. et al. Generation of a functional mammary gland from a single stem cell. Nature 439, 84-88

Royal Melbourne Hospital, Melbourne, Victoria, Australia
Nature (Impact Factor: 42.35). 02/2006; 439(7072):84-8. DOI: 10.1038/nature04372
Source: PubMed

ABSTRACT The existence of mammary stem cells (MaSCs) has been postulated from evidence that the mammary gland can be regenerated by transplantation of epithelial fragments in mice. Interest in MaSCs has been further stimulated by their potential role in breast tumorigenesis. However, the identity and purification of MaSCs has proved elusive owing to the lack of defined markers. We isolated discrete populations of mouse mammary cells on the basis of cell-surface markers and identified a subpopulation (Lin-CD29hiCD24+) that is highly enriched for MaSCs by transplantation. Here we show that a single cell, marked with a LacZ transgene, can reconstitute a complete mammary gland in vivo. The transplanted cell contributed to both the luminal and myoepithelial lineages and generated functional lobuloalveolar units during pregnancy. The self-renewing capacity of these cells was demonstrated by serial transplantation of clonal outgrowths. In support of a potential role for MaSCs in breast cancer, the stem-cell-enriched subpopulation was expanded in premalignant mammary tissue from MMTV-wnt-1 mice and contained a higher number of MaSCs. Our data establish that single cells within the Lin-CD29hiCD24+ population are multipotent and self-renewing, properties that define them as MaSCs.

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Available from: Mark J Shackleton, Jun 24, 2014
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    • "These processes are likely supported by a population of mammary stem cells that resides within the tissue. Regeneration of the entire gland from one single cell in multiple passages together with lineage-tracing experiments in vivo constitute compelling evidence for the existence of stem cell populations in the mouse mammary gland (Prater et al., 2014; Rios et al., 2014; Shackleton et al., 2006). However, owing to obvious experimental limitations, there is no direct definitive proof for the existence of a bona fide stem cell population active in the adult human mammary gland. "
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    ABSTRACT: Characterization of normal breast stem cells is important for understanding their role in breast development and in breast cancer. However, the identity of these cells is a subject of controversy and their localization in the breast epithelium is not known. In this study, we utilized a novel approach to analyze the morphogenesis of mammary lobules, by combining one-dimensional theoretical models and computer-generated 3D fractals. Comparing predictions of these models with immunohistochemical analysis of tissue sections for candidate stem cell markers, we defined distinct areas where stem cells reside in the mammary lobule. An increased representation of stem cells was found in smaller, less developed lobules compared to larger, more mature lobules, with marked differences in the gland of nulliparous versus parous women and that of BRCA1/2 mutation carriers versus non-carriers. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.
    Stem Cell Reports 03/2015; 4(4). DOI:10.1016/j.stemcr.2015.02.013 · 5.64 Impact Factor
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    • "We first demonstrated that LBH is predominantly expressed, with a nuclear-specific pattern, in the regenerative basal epithelium of both mouse and human mammary glands, including in WNTresponsive Lgr5 + MaSCs. By contrast, LBH was not or was only barely expressed in luminal cells, which lack regenerative capacity in transplantation assays (Shackleton et al., 2006; Stingl et al., 2006) and multi-lineage differentiation potential in situ (van Amerongen et al., 2012; Van Keymeulen et al., 2011). "
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    ABSTRACT: The identification of multipotent mammary stem cells (MaSCs) has provided an explanation for the unique regenerative capacity of the mammary gland throughout adult life. However, it remains unclear what genes maintain MaSCs and control their specification into the two epithelial lineages: luminal and basal. LBH is a novel transcription co-factor in the WNT pathway with hitherto unknown physiological function. LBH is expressed during mammary gland development and aberrantly overexpressed in aggressive 'basal' subtype breast cancers. Here, we have explored the in vivo role of LBH in mammopoiesis. We show that in postnatal mammary epithelia, LBH is predominantly expressed in the Lin(-)CD29(high)CD24(+) basal MaSC population. Upon conditional inactivation of LBH, mice exhibit pronounced delays in mammary tissue expansion during puberty and pregnancy, accompanied by increased luminal differentiation at the expense of basal lineage specification. These defects could be traced to a severe reduction in the frequency and self-renewal/differentiation potential of basal MaSCs. Mechanistically, LBH induces expression of key epithelial stem cell transcription factor ΔNp63 to promote a basal MaSC state and repress luminal differentiation genes, mainly that encoding estrogen receptor α (Esr1/ERα). Collectively, these studies identify LBH as an essential regulator of basal MaSC expansion/maintenance, raising important implications for its potential role in breast cancer pathogenesis. © 2015. Published by The Company of Biologists Ltd.
    Development 02/2015; 142(5). DOI:10.1242/dev.110403 · 6.27 Impact Factor
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    • "In this system, the tissue derived stem cells were embedded in Matrigel and cultured in the media that contained a cocktail of the growth factors, including ones that stimulate the WNT signaling pathways. We and others have previously shown that the MLTV-Wnt-1 tumor contains a CSC population (Shackleton et al., 2006; Cho et al., 2008). Because miR-142 is upregulated in the BCSCs and stimulates the canonical WNT signaling pathway that is an important regulator of the stem cell properties in mammary tissues, we tested the ability of miR-142 to regulate the organoid formation of BCSCs. "
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    ABSTRACT: MicroRNAs (miRNAs) are important regulators of stem and progenitor cell functions. We previously reported that miR-142 and miR-150 are upregulated in human breast cancer stem cells (BCSCs) as compared to the non-tumorigenic breast cancer cells. In this study, we report that miR-142 efficiently recruits the APC mRNA to an RNA-induced silencing complex, activates the canonical WNT signaling pathway in an APC-suppression dependent manner, and activates the expression of miR-150. Enforced expression of miR-142 or miR-150 in normal mouse mammary stem cells resulted in the regeneration of hyperproliferative mammary glands in vivo. Knockdown of endogenous miR-142 effectively suppressed organoid formation by BCSCs and slowed tumor growth initiated by human BCSCs in vivo. These results suggest that in some tumors, miR-142 regulates the properties of BCSCs at least in part by activating the WNT signaling pathway and miR-150 expression. DOI: http://dx.doi.org/10.7554/eLife.01977.001
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