Faculty: Patricia J. Keely, PhD
|Dept:||Professor and Chair, Cell & Regenerative Biology|
|Contact:|| 401 Bock
1525 Linden Drive
Appropriate cellular interactions with the extracellular matrix (ECM) help to establish normal cellular architecture and differentiation. During oncogenic transformation, these normal interactions with the ECM are profoundly altered, resulting in cells that lose their polarization and differentiation, lose anchorage dependent growth control, and acquire a migratory, invasive phenotype. Our lab is interested in understanding, at a molecular level, how cellular interactions with the ECM determine differentiation and epithelial polarization, and how these interactions are altered during carcinogenesis to result in invasive, metastatic carcinoma.
Figure 1. Mammary epithelial cells cultured in 3D collagen gels differentiate into tubule structures. This differentiation is disrupted when cells are cultured in dense 3D collagen gels, providing a model system for understanding the molecular underpinnings for cellularresponses to matrix density
Understanding molecular mechanisms underlying breast cancer risk due to breast density
Patients with “dense” breast tissue have a four to six-fold increased risk of developing breast carcinomas. In fact, 1/3 of all breast cancer cases are attributed to breast density, making it one of the greatest risk factors for carcinoma. Increased breast density is associated with a significant increase in the deposition of connective tissue, or extracellular matrix (ECM) components, most notably the protein, collagen. We have been developing model systems to understand why increased breast density results in an increased risk for developing breast carcinoma. We find in a simple in vitro model that increasing the density of collagen in the matrix is sufficient to disrupt breast epithelial differentiation, suggesting that matrix density is itself an important regulator of cellular behavior. Additionally, we are employing a mouse strain engineered to have more collagen in its connective tissue. Mouse tumor studies are underway to directly test whether increased collagen density will enhance tumor formation or tumor metastasis.
Figure 2. Mouse mammary carcinoma cells (blue) invading into the surrounding collagen stroma (green/yellow) in fresh, unstained, unfixed tissue, and visualized by Fluorescent Lifetime Imaging Microscopy
State of the art imaging approaches are being used to characterize the collagen structure in normal glands and around tumors so that we can better understand the physical relationship between cells and the collagen fibers found in breast tissue. We find evidence for a collagen “signature” that is present in even before a tumor is palpable, predicting where a tumor will soon arise. We are investigating whether this signature can be developed as a tool to aid in diagnosing human breast carcinoma at an earlier stage.
Using biochemical and DNA microarray approaches, we are characterizing several biochemical and genetic changes that occur in cells that encounter dense matrices. Dense collagen environments activate signal pathways within cells that result in a more tumor-like behavior: increased cell proliferation or growth, decreased cell death, and increased ability to invade into nearby tissues. We expect that our studies to characterize the molecular response of cells to dense collagen matrices will allow us to better understand tumor progression.
Molecular signaling events related to cell interactions with the ECM
Cells interact with the ECM through a variety of cell surface receptors, the best understood of which are members of the integrin family. Much remains to be determined regarding the specific molecular players and signaling pathways downstream of integrins, and how these pathways are involved in the progression of various diseases. Therefore, part of the focus of the lab is to investigate signaling events through the integrin family of receptors. A second aspect of this work is to investigate how small GTPases of the Ras superfamily, some of which are known or suspected oncogenes, affect the response of cells to the ECM. Specifically, we have focused on R-Ras and Rho, which we find alter the way breast epithelial cells respond to the ECM, promoting cellular migration and invasion. We are particularly interested in studying signaling events using state of the art imaging approaches to understand how small GTPases function in a spatial and temporal manner during cell migration.
Honors & Awards
- 2013 - Romnes Faculty Fellowship
- 2001 - Shaw Scientist Award
- Susan G. Komen-AACR Career Development Award
- Howard Hughes Medical Institute Start-up Award
Other Positions & Affiliations
- Laboratory for Cell and Molecular Biology
- Co-PI, Laboratory for Optical and Computational Instrumentation
- Affiliate Department of Biomedical Engineering
- Tumor Microenvironment Group, UW Carbone Cancer Center
- Karta MR, Gavala ML, Curran CS, Wickert LE,Keely PJ, Gern JE, Bertics PJ. (2014) Lipopolysaccharide Modulates Rhinovirus-Induced Chemokine Secretion in Monocytes and Macrophages.Am J Respir Cell Mol Biol. 2014 Feb 5. [Epub ahead of print] PMID: 24498897 [PubMed - as supplied by publisher]
- Bredfeldt JS, Liu Y, Pehlke CA, Conklin MW, Szulczewski JM, Inman DR,Keely PJ, Nowak RD, Mackie TR, Eliceiri KW. (2014) Computational segmentation of collagen fibers from second-harmonic generation images of breast cancer. J Biomed Opt. 2014 Jan;19(1):16007. doi: 10.1117/1.JBO.19.1.016007. PMID: 24407500 [PubMed - in process] --
- Keely PJ (2013). Proteolytic remodeling of the ECM and the geometric control of stem cell fate. Dev Cell. 25:325-326. PMID: 23725758 [PubMed - indexed for MEDLINE]
- Zhang K, Corsa CA, Ponik SM, Prior JL, Piwnica-Worms D, Eliceiri KW, Keely PJ, and Longmore GD (2013). The collagen receptor discoidin domain receptor 2 stabilizes SNAIL1 to facilitate breast cancer metastasis. Nat Cell Biol. 15:677-87. Epub 2013 May 5. PMID: 23644467 [PubMed - in process]
- Pugh TD, Conklin MW, Evans TD, Polewski MA, Barbian HJ, Pass R, Anderson BD, Colman RJ, Eliceiri KW, Keely PJ, Weindruch R, Beasley TM, and Anderson RM (2013). A shift in energy metabolism anticipates the onset of sarcopenia in rhesus monkeys. Aging Cell. 12:672-81. Epub 2013 May 27. PMID: 23607901 [PubMed - in process]
- Gehler S, Ponik SM, Riching KM, and Keely PJ (2013). Bi-directional signaling: extracellular matrix and integrin regulation of breast tumor progression. Crit Rev Eukaryot Gene Expr. 23:139-57. PMID: 23582036 [PubMed - in process]
- Ponik SM, Trier SM, Wozniak MA, Eliceiri KW, and Keely PJ (2013). RhoA is down-regulated at cell-cell contacts via p190RhoGAP-B in response to tensional homeostasis. Mol Biol Cell.24:1688-99, S1-3. Epub 2013 Apr 3. PMID: 23552690 [PubMed - in process]
- Barcus CE, Keely PJ, Eliceiri KW, and Schuler LA (2013). Stiff collagen matrices increase tumorigenic prolactin signaling in breast cancer cells. J Biol Chem. 288:12722-32. Epub 2013 Mar 24. PMID: 23530035 [PubMed - indexed for MEDLINE]