biostudies-literatureSaenz FRNCI NIH HHSe97666https://www.ebi.ac.uk/biostudies/studies/S-EPMC4022745biostudies-literatureUnknown9(5)Mammary epithelial (ME) cells cultured under conventional conditions senesce after several passages. Here, we demonstrate that mouse ME cells isolated from normal mammary glands or from mouse mammary tumor virus (MMTV)-Neu-induced mammary tumors, can be cultured indefinitely as conditionally reprogrammed cells (CRCs) on irradiated fibroblasts in the presence of the Rho kinase inhibitor Y-27632. Cell surface progenitor-associated markers are rapidly induced in normal mouse ME-CRCs relative to ME cells. However, the expression of certain mammary progenitor subpopulations, such as CD49f+ ESA+ CD44+, drops significantly in later passages. Nevertheless, mouse ME-CRCs grown in a three-dimensional extracellular matrix gave rise to mammary acinar structures. ME-CRCs isolated from MMTV-Neu transgenPloS oneConditionally reprogrammed normal and transformed mouse mammary epithelial cells display a progenitor-cell-like phenotype.PMC4022745R21 CA180524CA18052CA177466CA113477R33 CA177466P30 CA051008P30CA051008R01 CA113477T32 CA009686Liu XOry VWellstein ARiegel ATSaenz FRRosenfield SSchlegel RJohnson MDAlOtaiby MFurlong MCavalli LRfalseConditionally reprogrammed normal and transformed mouse mammary epithelial cells display a progenitor-cell-like phenotype.Mammary epithelial (ME) cells cultured under conventional conditions senesce after several passages. Here, we demonstrate that mouse ME cells isolated from normal mammary glands or from mouse mammary tumor virus (MMTV)-Neu-induced mammary tumors, can be cultured indefinitely as conditionally reprogrammed cells (CRCs) on irradiated fibroblasts in the presence of the Rho kinase inhibitor Y-27632. Cell surface progenitor-associated markers are rapidly induced in normal mouse ME-CRCs relative to ME cells. However, the expression of certain mammary progenitor subpopulations, such as CD49f+ ESA+ CD44+, drops significantly in later passages. Nevertheless, mouse ME-CRCs grown in a three-dimensional extracellular matrix gave rise to mammary acinar structures. ME-CRCs isolated from MMTV-Neu transgen2014-01-01T00:00:00Z20142025-04-18T20:55:43.505Z2019-03-26T23:24:50ZS-EPMC40227452483122810.1371/journal.pone.0097666