Project description:The Wnt/beta-catenin signalling pathway plays a central role in mammary stem cell homeostasis and in breast cancer. We employed the CD29hiCD24+ cell surface antigens to identify a subpopulation of mammary CSCs from Apc1572T/+, a mouse model for metaplastic breast adenocarcinoma, a subtype of triple-negative breast cancer in man. The MaCSCs are capable of recapitulating tumorigenesis when transplanted at low multiplicities in vivo, and of forming self-renewing organoids in vitro. Expression profiling of the different subpopulations sorted from normal and neoplastic mammary tissues revealed that the normal stem cell compartment is more similar to tumor cells than to their own differentiated progenies. Accordingly, Wnt signaling was found to be activated in the subpopulation encompassing normal mammary stem cells, though to a lesser degree than in the tumor cells. By comparing normal with cancer mouse mammary compartments, we were able to derive a MaCSC-specific signature composed of human orthologous genes able to predict poor survival, relapse and distant metastasis in human breast cancer. Finally, upon intravenous injection, only MaCSCs among the different tumor cell subpopulations are able to form metastatic lesions in a broad spectrum of anatomical sites. Overall, our data indicate that constitutive Wnt signaling activation interferes with mammary stem cell homeostasis leading to metaplasia and basal-like adenocarcinomas. The objective was to compare the: i) expression profiles between normal adult mammary stem cells and tumor cancer stem cells identified by Lin-CD29hiCD24+; ii) expression profile between adult stem cells and their differentiated counterparts both in normal and in tumor tissue to generate a cancer stem cell signature that can be used to compare with mammary human tumor expression data to predict survival and prognosis. To this aim five independent mammary adenocarcinomas from C57BL6/J Apc+/1572T mice and three independently isolated pools of mammary glands from C57BL6/J Apc+/+ mice were employed to sort 10,000 cells of each of the following populations: Lin-, Lin-CD29+CD24+ and Lin-CD29hiCD24+.
Project description:The Wnt/beta-catenin signalling pathway plays a central role in mammary stem cell homeostasis and in breast cancer. We employed the CD29hiCD24+ cell surface antigens to identify a subpopulation of mammary CSCs from Apc1572T/+, a mouse model for metaplastic breast adenocarcinoma, a subtype of triple-negative breast cancer in man. The MaCSCs are capable of recapitulating tumorigenesis when transplanted at low multiplicities in vivo, and of forming self-renewing organoids in vitro. Expression profiling of the different subpopulations sorted from normal and neoplastic mammary tissues revealed that the normal stem cell compartment is more similar to tumor cells than to their own differentiated progenies. Accordingly, Wnt signaling was found to be activated in the subpopulation encompassing normal mammary stem cells, though to a lesser degree than in the tumor cells. By comparing normal with cancer mouse mammary compartments, we were able to derive a MaCSC-specific signature composed of human orthologous genes able to predict poor survival, relapse and distant metastasis in human breast cancer. Finally, upon intravenous injection, only MaCSCs among the different tumor cell subpopulations are able to form metastatic lesions in a broad spectrum of anatomical sites. Overall, our data indicate that constitutive Wnt signaling activation interferes with mammary stem cell homeostasis leading to metaplasia and basal-like adenocarcinomas. The objective was to compare the: i) expression profiles between normal adult mammary stem cells and tumor cancer stem cells identified by Lin-CD29hiCD24+; ii) expression profile between adult stem cells and their differentiated counterparts both in normal and in tumor tissue to generate a cancer stem cell signature that can be used to compare with mammary human tumor expression data to predict survival and prognosis. To this aim five independent mammary adenocarcinomas from C57BL6/J Apc+/1572T mice and three independently isolated pools of mammary glands from C57BL6/J Apc+/+ mice were employed to sort 10,000 cells of each of the following populations: Lin-, Lin-CD29+CD24+ and Lin-CD29hiCD24+.
Project description:The mammary epithelium depends on specific lineages and their stem and progenitor function to accommodate hormone-triggered physiological demands in the adult female. Perturbations of these lineages underpin breast cancer risk, yet our understanding of normal mammary cell composition is incomplete. Here, we build a multimodal resource for the adult gland through comprehensive profiling of primary cell epigenomes, transcriptomes, and proteomes. We define systems-level relationships between chromatin–DNA–RNA–protein states, identify lineage-specific DNA methylation of transcription factor binding sites, and pinpoint proteins underlying progesterone responsiveness. Comparative proteomics of estrogen and progesterone receptor–positive and –negative cell populations, extensive target validation, and drug testing lead to discovery of stem and progenitor cell vulnerabilities. Top epigenetic drugs exert cytostatic effects; prevent adult mammary cell expansion, clonogenicity, and mammopoiesis; and deplete stem cell frequency. Select drugs also abrogate human breast progenitor cell activity in normal and high-risk patient samples. This integrative computational and functional study provides fundamental insight into mammary lineage and stem cell biology.
PMID: 29921600 (Table S5 and Table S7)
Project description:The aim of the experiment was to produce a mammary stem cell gene signature based on very high purity isolation of mouse mammary stem cells. Gene expression in the stem cells would be compared to gene expression in other cell types from the mammary epithelium to identify genes which may be important for regulation of mammary stem cell function.
Project description:Establishment and differentiation of mammary alveoli during pregnancy are controlled by prolactin through the transcription factor STAT5. As pregnancy progresses mammary signature genes are activated in a defined temporal order, which coincides with the recruitment of STAT5 to respective regulatory sequences. This study addressed the question whether the methyltransferase and transcriptional co-activator EZH2 controls the differentiation clock of mammary epithelium. Ablation of Ezh2 from mammary stem cells resulted in precocious differentiation of alveolar epithelium and accelerated activation of mammary signature genes. This coincided with enhanced occupancy by EZH1, Pol II and STAT5 to mammary-specific loci. Notably, loss of EZH2 did not result in overt changes in genome-wide and gene-specific H3K27me3 patterns, suggesting that enhanced EZH1 recruitment can compensate for the loss of EZH2. However, differentiated mammary epithelia failed to form in the combined absence of EZH1 and EZH2. Transplantation experiments failed to demonstrate a role for EZH2 in the biology of mammary stem and progenitor cells. In summary, while EZH1 and EZH2 serve redundant functions in the establishment of H3K27me3 and formation of mammary alveoli, the presence of EZH2 is required to obtain controlled temporal differentiation of mammary epithelium. ChIP-seq EZH1, EZH2, PolIII; WT and E2KO mammary cells
Project description:Examination of genome-wide, gene expression level differences among adult and fetal mammary sub-populations including fetal CD24high cells and adult CD49fhighCD24medium cells which harbor enriched mammary stem cell activity.
Project description:We previously identified a gene signature predicted to regulate the epithelial-mesenchymal transition (EMT) in both epithelial tissue stem cells and breast cancer cells. A phenotypic RNA interference (RNAi) screen identified the genes within this 140-gene signature that promoted the conversion of mesenchymal epithelial cell adhesion molecule-negative (EpCAM-) breast cancer cells to an epithelial EpCAM+/high phenotype. The screen identified 10 of the 140 genes whose individual knockdown was sufficient to promote EpCAM and E-cadherin expression. Among these 10 genes, RNAi silencing of the SWI/SNF chromatin-remodeling factor Smarcd3/Baf60c in EpCAM- breast cancer cells gave the most robust transition from the mesenchymal to epithelial phenotype. Conversely, expression of Smarcd3/Baf60c in immortalized human mammary epithelial cells induced an EMT. The mesenchymal-like phenotype promoted by Smarcd3/Baf60c expression resulted in gene expression changes in human mammary epithelial cells similar to that of claudin-low triple-negative breast cancer cells. These mammary epithelial cells expressing Smarcd3/Baf60c had upregulated Wnt5a expression. Inhibition of Wnt5a by either RNAi knockdown or blocking antibody reversed Smarcd3/Baf60c-induced EMT. Thus, Smarcd3/Baf60c epigenetically regulates EMT by activating WNT signaling pathways. sampleXreference
Project description:The transcription factor c-Myb has been well characterized as an oncogene in several human tumor types, and its expression in the hematopoietic stem/progenitor cell population is essential for proper hematopoiesis. However, the role of c-Myb in mammopoeisis and breast tumorigenesis is poorly understood, despite its high expression in the majority of breast cancer cases (60-80%). We find that c-Myb high expression in human breast tumors correlates with the luminal/ER+ phenotype and a good prognosis. RNAi knock-down of endogenous c-Myb levels in the MCF7 luminal breast tumor cell line increases tumorigenesis both in vitro and in vivo, suggesting a tumor suppressor role in luminal breast cancer. We created a mammary-derived c-Myb expression signature and found it to be highly correlated with a published mature luminal mammary cell signature and least correlated with a mammary stem/progenitor lineage gene signature. These data describe, for the first time, a tumor suppressor role for the c-Myb proto-oncogene in breast cancer that has implications for understanding luminal tumorigenesis and for guiding treatment. refXsample