Project description:Skin-mammary specific knockout (SSKO) of Pygo2 (K14-cre; Pygo2 flox/-) , a WNT signaling co-activator, results in defective mouse mammary gland development. The FACS sorted mammary stem cell (MaSC)/basal population from Pygo2 SSKO mammary gland displays biased differentiation towards luminal/alveolar lineage in vitro, and reduced regeneration rate of new mammary gland in vivo To gain the insight into gene expression profiles in control and Pygo2 SSKO mammary epithelial cells (MECs), we sorted the freshly isolated mouse MECs into MaSC/basal (Lin-CD29hiCD24+) and mature luminal population (Lin-CD29lowCD24+CD61-), and extract total RNA for cDNA microarray analysis
Project description:Three well-known tumor suppressors, TRP53, p16INK4a, and p19ARF (p16INK4a and p19ARF are both coded by the gene Cdkn2a) have been connected to the limiting of stem cell self-renewal and proliferation in some tissues. Here we deposit RNA microarray expression data of sorted mouse Krt14-cre mT/mG Trp53f/f Cdkn2a-/- mammary epithelial basal cells and their wild type control cells (Krt14-cre mT/mG).
Project description:The basal cell lineage in the mouse mammary gland is perceived to be composed mostly of differentiated myoepithelial cells intermixed with a rare subpopulation of mammary stem cells. Here, we show that a high proportion (~30%) of basal cells have colony forming capacity when actin-myosin contraction is prevented. A basal cell subpopulation enriched for mammary repopulating units (MRUs) is shown to be enriched for dividing cells. Inducing basal cells to proliferate in vitro increases MRU frequency 10-fold and permits a ~750-fold expansion of MRUs. Transplantation of single-cell-derived basal colonies into cleared fat pads demonstrates that the majority (~80%) of these colonies can repopulate a mammary gland. This suggests that a high proportion of basal cells, most of which were previously perceived to be terminally differentiated myoepithelial cells, have latent mammary stem cell potential. Mammary glands from 10-14 week old, female, virgin C57BL/6J mice were dissociated into single cells and basal cells were sorted by flow cytometry at a purity of ~95%. Inducing basal cell proliferation in vitro causes mammary stem cell expansion over 7 days in culture. Basal cells were cultured on Matrigel-coated cell culture plastic in a keratinocyte stem cell media supplemented with the Rho kinase inhibitor Y-27632 and were co-seeded with irradiated NIH 3T3 fibroblast feeder cells. In order to determine the molecular changes that occur during culture that may contribute to mammary stem cell expansion, gene expression profiling was conducted on basal cells pre-culture and after 1- or 7-day-culture.
Project description:Differentiation of stem cells embedded within the mammary epithelium is orchestrated by lineage-specifying transcription factors. Unlike the well-defined luminal hierarchy, dissection of the basal lineage has been hindered by a lack of specific markers. Inhibitor of Differentiation 4 (ID4) is a basally-restricted helix-loop-helix (HLH) transcription factor essential for mammary development. Here we show that ID4 is highly expressed in basal stem cells and decreases during myoepithelial differentiation. By integrating transcriptomic, proteomic and chromatin-association data we reveal that ID4 is required to suppress myoepithelial gene expression and cell fate.
Project description:CCAAT/enhancer binding protein beta (C/EBPb) is a member of a family of highly conserved transcription factors that regulates numerous genes involved in proliferation and differentiation in a variety of tissues. C/EBPb is deregulated in human breast cancer and germline deletion of this gene results in multiple defects in mammary gland development. We hypothesized that C/EBPb regulates mammary stem cell self-renewal, maintenance and/or differentiation through the regulation of multiple target genes that coordinate mammary gland development. Utilizing both a germline knockout mouse model and a conditional knockout strategy, we demonstrated that mammosphere formation was significantly decreased in C/EBPb-deficient mammary epithelial cells (MECs). The ability of C/EBPb-deleted MECs to regenerate the mammary gland in vivo was severely impaired when transplanted at limiting dilution. Furthermore, serial transplantation of C/EBPb-null mammary tissue resulted in decreased outgrowth potential when compared to wildtype, and an early senescence phenotype. Flow cytometric analysis revealed that C/EBPb-null MECs contain a lower frequency of repopulating stem cells accompanied by an increase in committed, differentiated luminal cells as compared to wildtype. Microarray analysis of stem/progenitor cell populations was performed and revealed an alteration in cell fate specification in C/EBPb-null glands, exemplified by the aberrant expression of basal markers in the luminal cell compartment. Collectively, our studies demonstrate that C/EBPb is a critical regulator of mammary stem cell differentiation, and an important determinant of luminal cell fate specification. Experiment Overall Design: To identify potential signaling pathways regulated by C/EBPb in stem/progenitor cells, microarray analysis was performed on two stem/progenitor cell subpopulations. For this analysis, subpopulations defined by LIN-CD24+CD29hi and LIN-CD24hiCD29lo were FACS sorted from wildtype and germline C/EBPb-/- glands, and RNA was isolated from each group.
Project description:Skin-mammary specific knockout (SSKO) of Pygo2 (K14-cre; Pygo2 flox/-) , a WNT signaling co-activator, results in defective mouse mammary gland development. The FACS sorted mammary stem cell (MaSC)/basal population from Pygo2 SSKO mammary gland displays biased differentiation towards luminal/alveolar lineage in vitro, and reduced regeneration rate of new mammary gland in vivo
Project description:MLL3 inactivation mutations occurs frequently in human breast cancer. To understand the function of MLL3 inactivation, we compared the gene expression profiles of the vector control (WT) and Mll3-null mouse mammary stem cells generated by CRISPR. Affymetrix mouse Gene 2.0ST ships were used for microarray.
Project description:In order to understand gene regulation of epithelial cells in the mouse mammary gland, we have generated a comprehensive epigenetic atlas from freshly sorted myoepithelial (basal), luminal progenitor (LP) and mature luminal (ML) from adult mice (9 week-old) encompassing gene expression profiling, histone and polymerase II CUT&Tag sequencing, chromatin accessibility via ATAC-seq and chromatin interactions. We further studied the basal compartment by sorting to additional cell type population: Tspan8+ (quiescent basal, QBa) and Tspan8- (active basal, ABa) cells. We then performed gene expression profiling analysis using data obtained from RNA-seq of 2 different cell types Tspan8+ and Tspan8- cells.
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+.