.The long-term objective is to improve breast cancer prevention strategies. This project exploits genetically engineered mouse models representing clinically relevant molecular aberrations in estrogen signaling in parallel with human breast tissue from high-risk women to address three needs. One, on-going discovery of candidate in vivo biomarkers and pathways of intrinsic resistance. Two, development of a human tissue based system to parallel our mouse-based experimental models. Three, comparison of efficacy and mechanism of alternative agents to tamoxifen. Genetically engineered mice model the pathophysiology of some types of breast cancer found in high-risk women. Primary tissue from high-risk women represents the 'real thing'but as the tissue and cells are moved into in vitro environments to perform experiments they also become model systems. Fixed tissue and studies of gene expression at specific time points provide static but informative representations of the high-risk breast environment. New in vitro systems are needed to improve projections of predicted benefit to therapeutic agents in different genetic environments, to 'personalize'medical intervention. Objective1. Compare impact of alternative preventive agents raloxifene, letrozole and efatutazone to tamoxifen in genetic settings exhibiting or likely to exhibit intrinsi tamoxifen resistance. Objective 2. Create a living biobank of human primary non-malignant but 'high breast cancer risk'mammary epithelial cells. Investigate in vitro approaches for testing tamoxifen (and other candidate preventive agents in the future) sensitivity using this living biobank. Objective 3. Explore alternative schedules of administration to increase effectiveness and/or reduce toxicity for an alternative preventive agent efatutazone, a PPAR? agonist, which has potential to prevent both ER+ and ER- breast cancer. Methods: Employ five genetically engineered mouse models (combinations of conditional increased Esr1 (Estrogen Receptor alpha) or CYP19A1 (Aromatase) expression in mammary epithelial cells and mammary epithelial cell-targeted loss of full-length Brca1 with germline Trp53 haploinsufficiency) as well as primary human mammary epithelial cells in experiments that employ large-scale screening technologies (RNAseq and reverse phase protein microarrays), primary cell culture under different conditions (conditional reprogrammed cells, spheroid and mammosphere culture), with administration of different candidate preventive agents tamoxifen, raloxifene, letrozole and efatutazone. Relevance: Tamoxifen is the only Selective Estrogen Receptor Modulator (SERM) currently FDA- approved for breast cancer prevention in pre- and post-menopausal women with raloxifene approved for post- menopausal women. This study will provide a molecular understanding of how different genetic lesions influence preventive agent response, explore development of in vitro systems that could test preventive agent response in clinical samples, and test if different treatment schedules can improve the therapeutic ratio of the PPAR? agonist efatutazone.
Intrinsic resistance to tamoxifen compromises its effectiveness as a breast cancer chemopreventative for some women. This project will identify genetic biomarkers of intrinsic tamoxifen resistance, develop an in vitro system to test tamoxifen sensitivity in clinical specimens, and investigate alternative preventive agents raloxifene, letrozole and efatutazone.
|Alothman, Sahar J; Wang, Weisheng; Goerlitz, David S et al. (2017) Responsiveness of Brca1 and Trp53 Deficiency-Induced Mammary Preneoplasia to Selective Estrogen Modulators versus an Aromatase Inhibitor in Mus musculus. Cancer Prev Res (Phila) 10:244-254|
|Alamri, Ahmad M; Kang, Keunsoo; Groeneveld, Svenja et al. (2016) Primary cancer cell culture: mammary-optimized vs conditional reprogramming. Endocr Relat Cancer 23:535-54|
|Bae, Woo Kyun; Yoo, Kyung Hyun; Lee, Ji Shin et al. (2015) The methyltransferase EZH2 is not required for mammary cancer development, although high EZH2 and low H3K27me3 correlate with poor prognosis of ER-positive breast cancers. Mol Carcinog 54:1172-80|
|Dabydeen, Sarah A; Kang, Keunsoo; Díaz-Cruz, Edgar S et al. (2015) Comparison of tamoxifen and letrozole response in mammary preneoplasia of ER and aromatase overexpressing mice defines an immune-associated gene signature linked to tamoxifen resistance. Carcinogenesis 36:122-32|
|Okolowsky, Nadia; Furth, Priscilla A; Hamel, Paul A (2014) Oestrogen receptor-alpha regulates non-canonical Hedgehog-signalling in the mammary gland. Dev Biol 391:219-29|
|Assefnia, Shahin; Kang, Keunsoo; Groeneveld, Svenja et al. (2014) Trp63 is regulated by STAT5 in mammary tissue and subject to differentiation in cancer. Endocr Relat Cancer 21:443-57|
|Mahmoodzadeh, Shokoufeh; Leber, Joachim; Zhang, Xiang et al. (2014) Cardiomyocyte-specific Estrogen Receptor Alpha Increases Angiogenesis, Lymphangiogenesis and Reduces Fibrosis in the Female Mouse Heart Post-Myocardial Infarction. J Cell Sci Ther 5:153|
|Dabydeen, Sarah A; Furth, Priscilla A (2014) Genetically engineered ER?-positive breast cancer mouse models. Endocr Relat Cancer 21:R195-208|
|Ory, V; Tassi, E; Cavalli, L R et al. (2014) The nuclear coactivator amplified in breast cancer 1 maintains tumor-initiating cells during development of ductal carcinoma in situ. Oncogene 33:3033-42|
|Nakles, Rebecca E; Millman, Sarah L; Cabrera, M Carla et al. (2013) Time-lapse imaging of primary preneoplastic mammary epithelial cells derived from genetically engineered mouse models of breast cancer. J Vis Exp :|
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