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MiRNA expression profiling in human mammary epithelial cell (HMEC) CD24-CD44+ and non-CD24-CD44+ cell populations

ABSTRACT: To understand the role of p53 in regulating stem cell population (CD24-CD44+) and stemness-associated miRNAs, we first compared miRNA expression profiles between human mammary epithelical cells knocked-down p53 and control cells. We then cross-referenced p53-regulated miRNAs with stemness-associated miRNAs analyzed from expression profiling of sorted CD24-CD44+ and non-CD24-CD44+ cell populations. Further biological experiments were performed with the miRNAs that are altered in CD24-CD44+ stem cell populations and also regulated by p53.

ORGANISM(S): Merkel cell polyomavirus Human gammaherpesvirus 8 Mus musculus JC polyomavirus Rattus norvegicus Betapolyomavirus macacae Murid gammaherpesvirus 4 Homo sapiens Human immunodeficiency virus 1 Human betaherpesvirus 5 Human alphaherpesvirus 2 Betapolyomavirus hominis Human alphaherpesvirus 1 human gammaherpesvirus 4 Murid betaherpesvirus 1

PROVIDER: GSE25036 | GEO | 2011/02/01

SECONDARY ACCESSION(S): PRJNA142753

REPOSITORIES: GEO

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Project description:Tumorigenic breast cancer cells characterized by CD44 expression and low or undetectable CD24 levels (CD44+/CD24-/low) may be resistant to chemotherapy and therefore responsible for cancer relapse. Paired breast cancer core biopsies before and after neoadjuvant chemotherapy or lapatinib were obtained and as single cell suspensions stained using antibodies against CD24, CD44, and lineage markers, and then analyzed by flow cytometry. Mammosphere (MS) formation in culture was compared before and after treatment. Global gene expression differences between cancer cells bearing CD44+/CD24-/low cells and all other sorted cells, and between cancer MS and the primary bulk invasive cancers were analyzed. We report that CD44+/CD24-/low tumorigenic breast cancer cells were intrinsically chemoresistant â chemotherapy led to increased CD44+/CD24-/low cells, increased self-renewal capacity on MS assays, and enhanced tumorigeneicity in immunocompromised SCID/Beige mice. Conversely, in patients with HER2 overexpressing tumors, the EGFR/HER2 tyrosine kinase inhibitor, lapatinib decreased CD44+/CD24-/low cells, with the majority of these patients after conventional therapy achieving pathologic complete response, a validated surrogate marker for long-term survival. Gene transcription pathways that underlie chemoresistant, MS-forming CD44+/CD24-/low cells involve genes belonging to stem cell self-renewal, Wnt signaling, and early development pathways. Experiment Overall Design: Human breast tumor samples were sorted using flow cytometry to select for cells that were CD44+ and CD24-. Gene expression profiles of these cells were compared with profiles of the other sorted cells (CD24+ and CD44-/CD24-). Experiment Overall Design: Core biopsies of primary breast tumors were taken and placed immediately in cold RPMI-1640 supplemented with 10% heat-inactivated newborn calf serum (HINCS, Invitrogen, Carlsbad, CA). Within an hour, the samples were minced and then digested in 10-15 mL of MEGM with 250-300 units/mL collagenase at 370C. The samples were filtered, washed, and then subjected to hypotonic shock to lyse red blood cells. About 106 single cells were re-suspended, incubated for 15 min at 40C with anti-CD44 (APC), anti-CD24 (FITC), and anti-lineage cocktail antibodies (PE-conjugated anti-CD2, CD3, CD10, CD16, CD18, CD31 and CD 140B) (Pharmingen, San Diego, CA) using the manufacturerâs suggested concentrations. The cells were then washed twice, re-suspended with the viability dye propidium iodide, and analyzed using Dako MoFlo flow cytometry. Side- and forward- scatter were used to eliminate debris and cell doublets, and the Lin- cells were further analyzed by CD44 and CD24 markers.

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MiRNA expression profiling in human mammary epithelial cell (HMEC) CD24-CD44+ and non-CD24-CD44+ cell populations

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