There is increasing evidence that breast and other cancers originate from and are maintained by a small fraction of stem/progenitor cells with self-renewal properties. Whether such cancer stem/progenitor cells originate from normal stem cells based on initiation of a de novo stem cell program, by reprogramming of a more differentiated cell type by oncogenic insults or both remains unresolved. A major hurdle in addressing these issues is lack of immortal human stem/progenitor cells that can be deliberately manipulated in vitro. We present evidence that normal and human telomerase reverse transcriptase (hTERT)-immortalized human mammary epithelial cells (hMECs) isolated and maintained in DFCI-1 medium retain a fraction with progenitor cell properties. These cells co-express basal, luminal and stem/progenitor cell markers. Clonal derivatives of progenitors co-expressing these markers fall into two distinct types: K5+/K19- (Type I) and K5+/K19+ (Type II). We show that both types of progenitor cells have self-renewal and differentiation ability. Through microarray analysis, we want to identify genes and pathways linked to human mammary epithelial stem/progenitor cell self-renewal and differentiation.
Telomerase-immortalized human mammary stem/progenitor cells with ability to self-renew and differentiate.
Sex, Specimen part
View SamplesThe reduced folate carrier (RFC1) is an integral membrane protein and facilitative anion exchanger that mediates delivery of 5-methyltetrahydrofolate into mammalian cells. Adequate maternal-fetal transport of folate is necessary for normal embryogenesis. Targeted inactivation of the murine RFC1 gene results in post-implantation embryo lethality, but daily folic acid supplementation of pregnant dams prolongs survival of homozygous embryos until mid-gestation. At E10.5 RFC1-/- embryos are developmentally delayed relative to wildtype littermates, have multiple malformations, including neural tube defects, and die due to failure of chorioallantoic fusion. The mesoderm is sparse and disorganized, and there is a marked absence of erythrocytes in yolk sac blood islands. Affymetrix microarray analysis and quantitative RT-PCR validation of the relative gene expression profiles in E9.5 RFC1-/- vs. RFC1+/+ embryos indicates a dramatic downregulation of multiple genes involved in erythropoiesis, and upregulation of several genes that form the cubilin-megalin multiligand endocytic receptor complex. Megalin protein expression disappears from the visceral yolk sac of RFC1-/- embryos, and cubilin protein is widely misexpressed. Inactivation of RFC1 impacts the expression of several ligands and interacting proteins in the cubilin-amnionless-megalin complex that are involved in the maternal-fetal transport of folate, vitamin B12, and other nutrients, lipids and morphogens required for normal embryogenesis.
Microarray analysis of E9.5 reduced folate carrier (RFC1; Slc19a1) knockout embryos reveals altered expression of genes in the cubilin-megalin multiligand endocytic receptor complex.
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View SamplesAda3 (alteration/deficiency in activation) is a transcriptional adaptor that forms a core structural component of multiple HAT complexes. In order to gain insights into physiological roles of Ada3, we made a conditional knockout mouse for Ada3 which was early embryonic lethal. Deletion of Ada3 in MEFs by using Adenovirus-Cre showed changes in global histone acetylation.
Mammalian alteration/deficiency in activation 3 (Ada3) is essential for embryonic development and cell cycle progression.
Specimen part
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