Epithelial cells within glandular tissues, like the breast, are organized into ducts and specialized spherical structures containing a monolayer of luminal epithelial cells surrounding a hollow lumen. Maintenance of this specialized architecture and suppression of aberrant cell proliferation is mediated by controls that restrict the survival of cells which proliferate into the hollow lumen or outside of their normal niche. Our previous studies have provided evidence that a major factor contributing to death of cells outside the epithelial monolayer is lack of appropriate matrix attachment. In addition, we found that both apoptotic and non-apoptotic death processes are activated in cells deprived of their appropriate matrix. Survival of aberrant proliferating cells is dependent on escape from both of these death processes. In this proposal, we describe studies, using three different experimental models- 1) Suspended, matrix-deprived breast epithelial cells in culture, 2) 3D acinar structures cultured in reconstituted basement membrane proteins, and 3) Terminal end buds (TEBs) of pubertal mouse mammary glands in vivo. Using these model systems, we will elucidate the mechanisms apoptotic and non- apoptotic death of cells lacking proper matrix attachment. In addition, we will examine the mechanisms involved in oncogene-mediated escape from these death mechanisms using both biased pathway dissection studies and unbiased siRNA screens. Lastly, we will examine the importance of one proapoptotic protein, Bim, in tumor initiation and progression. We have previously shown that Bim is required for apoptosis in all three experimental models. The studies proposed in this application will investigate the consequences of loss or gain of Bim expression in several mouse tumor models and examine Bim expression in human breast tumors. These studies will provide valuable information on the cellular pathways that are required for maintenance of tumor cell survival, the role of apoptotic proteins in breast tumor progression, and potentially identify targets for therapeutic elimination of tumor cells.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
3R01CA105134-09S1
Application #
8475720
Study Section
Cancer Molecular Pathobiology Study Section (CAMP)
Program Officer
Mohla, Suresh
Project Start
2003-09-30
Project End
2013-03-31
Budget Start
2011-08-01
Budget End
2013-03-31
Support Year
9
Fiscal Year
2012
Total Cost
$126,750
Indirect Cost
$51,750
Name
Harvard University
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
047006379
City
Boston
State
MA
Country
United States
Zip Code
02115
Albeck, John G; Mills, Gordon B; Brugge, Joan S (2013) Frequency-modulated pulses of ERK activity transmit quantitative proliferation signals. Mol Cell 49:249-61
Leung, Cheuk T; Brugge, Joan S (2012) Outgrowth of single oncogene-expressing cells from suppressive epithelial environments. Nature 482:410-3
Muranen, Taru; Selfors, Laura M; Worster, Devin T et al. (2012) Inhibition of PI3K/mTOR leads to adaptive resistance in matrix-attached cancer cells. Cancer Cell 21:227-39
Worster, Devin T; Schmelzle, Tobias; Solimini, Nicole L et al. (2012) Akt and ERK control the proliferative response of mammary epithelial cells to the growth factors IGF-1 and EGF through the cell cycle inhibitor p57Kip2. Sci Signal 5:ra19
Mouneimne, Ghassan; Hansen, Scott D; Selfors, Laura M et al. (2012) Differential remodeling of actin cytoskeleton architecture by profilin isoforms leads to distinct effects on cell migration and invasion. Cancer Cell 22:615-30
Grassian, Alexandra R; Metallo, Christian M; Coloff, Jonathan L et al. (2011) Erk regulation of pyruvate dehydrogenase flux through PDK4 modulates cell proliferation. Genes Dev 25:1716-33
Krajcovic, Matej; Johnson, Nicole B; Sun, Qiang et al. (2011) A non-genetic route to aneuploidy in human cancers. Nat Cell Biol 13:324-30
Grassian, Alexandra R; Schafer, Zachary T; Brugge, Joan S (2011) ErbB2 stabilizes epidermal growth factor receptor (EGFR) expression via Erk and Sprouty2 in extracellular matrix-detached cells. J Biol Chem 286:79-90
Wang, Lixin; Brugge, Joan S; Janes, Kevin A (2011) Intersection of FOXO- and RUNX1-mediated gene expression programs in single breast epithelial cells during morphogenesis and tumor progression. Proc Natl Acad Sci U S A 108:E803-12
Iwanicki, Marcin P; Davidowitz, Rachel A; Ng, Mei Rosa et al. (2011) Ovarian cancer spheroids use myosin-generated force to clear the mesothelium. Cancer Discov 1:144-57

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