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Expression data comparing Rb/p53 and p53 deficient mammary tumors and normal mammary tissue

ABSTRACT: To investigate the impact of combined Rb and p53 loss in mammary tumorigenesis, we used transgenic and viral approaches to delete Rb and p53 floxed alleles specifically in the mouse mammary epithelium. Although MMTV-Cre (NLST) targets stem/bi-potent progenitors in the mammary gland, a subset of MMTV-Cre:Rbf/f;p53f/f mice developed non-mammary tumors. Thus, freshly isolated primary mammary epithelial cells from these animals were transplanted into the mammary fat pads of immunodeficient mice and monitored for tumor formation. In addition, primary MECs were isolated from Cre-negative Rbf/f;p53f/f mice, infected with Ad-Cre followed by orthotopic transplantation. In all these cases, resulting tumors shared similar spindle-shape histology, expressed high levels of vimentin, a mesenchymal marker, but not E-cadherin, a luminal marker, and were classified as adeno-sacrcomatoid/spindle-cell/mesenchymal-like breast cancer. We used microarrays to detect differentially expressed genes in the Rb/p53 double-knock-out vs p53 single deletion or normal mammary tissue.

ORGANISM(S): Mus musculus

PROVIDER: GSE62016 | GEO | 2014/10/03

SECONDARY ACCESSION(S): PRJNA262942

REPOSITORIES: GEO

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Project description:To model the effect of Pten loss on breast cancer, we deleted Pten using a floxed allele and the deleter lines MMTV-Cre(NLST), which targets stem/bi-potent progenitor cells, and WAP-Cre, which targets CD24-positive, pregnancy-identified stem cells/alveolar progenitors. Mammary tumors were detected in WAP-Cre:Ptenf/f females with a latency of 15.2 months. By 18 months, nearly all mice had succumbed to cancer. MMTV-Cre:Ptenf/f mice developed mammary tumors after a longer latency of 26.4 months and reduced penetrance (70%) compared to WAP-Cre:Ptenf/f mice. Tumors from both models were heterogeneous, consisting primarily of differentiated adenocarcinoma (adenomyoepithelioma; ~70%) and adenosquamous carcinoma (20-25%). In addition, a small fraction of tumors was classified as acinar and poorly differentiated adenocarcinoma (4-7%) and adenosarcoma (3-4%). To test the consequences of combined Pten and p53 gene mutation on breast cancer, we deleted both genes via MMTV-Cre or WAP-Cre. Kaplan-Meier tumor free survival curves revealed that WAP-Cre:Ptenf/f:p53f/f and MMTV-Cre:Ptenf/f:p53f/f females developed tumors with reduced latency of 11.3 and 9.8 months, compared with 15.2, 26.4, and 16.9 months for single-mutant WAP-Cre:Ptenf/f, MMTV-Cre:Ptenf/f or MMTV-Cre:p53f/f mice, respectively. In contrast to the heterogeneity of Pten tumors and small percentage of adenosarcomas in these mice, ~70% of Pten:p53 lesions were histologically classified as adeno-sacrcomatoid-like or mesenchymal-like breast cancer, with the rest exhibiting mixed mesenchymal plus adenocarcinomas and differentiated adenocarcinomas. The adeno-sacrcomatoid-like tumors expressed the mesenchymal markers vimentin, K5, SMA, N-cadherin and desmin but not ER, as well as islands of luminal-like K18 expressing cells surrounded by a layer of K14-positive cells. We used microarrays to detect differentially expressed genes in the Pten:p53 double-knock-out vs Pten or p53 single deletions Total RNA was extracted from tumors developed by double Trizol method and hybridized on Affymetrix microarrays.

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Expression data comparing Rb/p53 and p53 deficient mammary tumors and normal mammary tissue

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