. The role of ?3?1 integrin in malignancy is complex: while some studies have indicated a tumor suppressive role, many others have shown that ?3?1 is a potent promoter of tumor cell adhesion, motility and invasion. This paradox may be reconciled by the fact that, in addition to ?3?1's ability to mediate rapid mi- gration on laminin-5, it can also transduce signals that promote the stable organization of E-cadherin-based adherens junctions. The balance between these opposing ?3?1 functions may be regulated by ?3?1- associated tetraspanin proteins. In particular, the loss of tetraspanin CD9 in tumor cells is linked to enhanced metastasis in clinical and experimental studies. Despite these data, neither the ?3?1 loss-of-function pheno- type nor the role of ?3?1's junction-stabilizing activity has been explored in the context of tumor biology. Our long term goal is to understand how tumor-host interactions can be manipulated to inhibit tumor cell metasta- sis. The objectives of this application are to (i) determine the role of ?3?1 integrin in regulating collective tumor cell migration, local invasion, and metastatic colonization in conjunction with, and independently of, its ability to promote adherens junction stability, and (ii) define the mechanism by which ?3?1 signals to promote the stabil- ity of carcinoma cell-cell junctions. The central hypothesis is that ?3?1's ability to promote tumor invasion and metastatic colonization is balanced by ?3?1's ability to promote adherens junction stability by a mechanism that depends on ?3?1 association with tetraspanin CD9. This hypothesis will be tested in three specific aims. The first specific aim is to determine the roles of ?3?1 integrin, tetraspanin CD9, and ?3?1-CD9 association in promoting carcinoma cell junctional stability. Using epidermoid and breast carcinoma cells in which we have manipulated (i) ?3 or CD9 expression, (ii) ?3?1-CD9 association, and (iii) ?3?1 ligand binding, we will assess adherens junction organization and stability, collective cell migration, and the cellular dynamics within intact cell sheets. The second specific aim is to define the role of ?3?1 integrin expression and association with CD9 in tumor invasion and metastatic colonization. We will use a novel orthotopic invasion assay for epidermal carcinoma cells and an established orthotopic model of spontaneous breast cancer metastasis to test tumor cells in which ?3 integrin or CD9 expression, ?3-CD9 association, or ?3 ligand binding have been separately manipulated. The third specific aim is to determine the mechanism by which ?3?1 signals to promote adher- ens junction stability. We will use our tumor cell variants together with selective inhibitors and activators of specific cytoplasmic signaling effectors identified in our preliminary experiments to determine the connection between ?3?1 signaling and the resulting stabilization of adherens junctions. Collectively, the experiments in this proposal are expected to provide critical data on the function of ?3?1 in metastatic colonization, and how it relates to ?3?1's role as a regulator of E-cadherin. Such results may yield important information on the suit- ability of ?3?1 integrin, its associated proteins, and downstream effectors as therapeutic targets in malignancy.

Public Health Relevance

to human health. To develop more effective and efficient cancer treatments, a major goal is to identify methods for controlling metastasis without harming healthy tissue. The proposed studies are relevant to this goal because they are expected to illuminate an as yet poorly understood mechanism that regulates the ability of tumor cells to metastasize. Once we understand more about the factors that contribute to metastasis, we may be able to identify tumor-specific processes that could be therapeutically targeted.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA136664-05
Application #
8460953
Study Section
Tumor Progression and Metastasis Study Section (TPM)
Program Officer
Woodhouse, Elizabeth
Project Start
2009-07-01
Project End
2014-04-30
Budget Start
2013-05-01
Budget End
2014-04-30
Support Year
5
Fiscal Year
2013
Total Cost
$281,612
Indirect Cost
$92,413
Name
University of Iowa
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
062761671
City
Iowa City
State
IA
Country
United States
Zip Code
52242
Varzavand, Afshin; Hacker, Will; Ma, Deqin et al. (2016) α3β1 Integrin Suppresses Prostate Cancer Metastasis via Regulation of the Hippo Pathway. Cancer Res :
Zevian, Shannin C; Johnson, Jessica L; Winterwood, Nicole E et al. (2015) CD151 promotes α3β1 integrin-dependent organization of carcinoma cell junctions and restrains collective cell invasion. Cancer Biol Ther 16:1626-40
Zhou, Bo; Gibson-Corley, Katherine N; Herndon, Mary E et al. (2014) Integrin *3*1 can function to promote spontaneous metastasis and lung colonization of invasive breast carcinoma. Mol Cancer Res 12:143-54
Esser, Alison K; Miller, Michael R; Huang, Qin et al. (2013) Loss of LARGE2 disrupts functional glycosylation of α-dystroglycan in prostate cancer. J Biol Chem 288:2132-42
Gustafson-Wagner, Elisabeth; Stipp, Christopher S (2013) The CD9/CD81 tetraspanin complex and tetraspanin CD151 regulate ýý3ýý1 integrin-dependent tumor cell behaviors by overlapping but distinct mechanisms. PLoS One 8:e61834
Varzavand, Afshin; Drake, Justin M; Svensson, Robert U et al. (2013) Integrin α3β1 regulates tumor cell responses to stromal cells and can function to suppress prostate cancer metastatic colonization. Clin Exp Metastasis 30:541-52
Jannie, Karry M; Stipp, Christopher S; Weiner, Joshua A (2012) ALCAM regulates motility, invasiveness, and adherens junction formation in uveal melanoma cells. PLoS One 7:e39330
Zevian, Shannin; Winterwood, Nicole E; Stipp, Christopher S (2011) Structure-function analysis of tetraspanin CD151 reveals distinct requirements for tumor cell behaviors mediated by ýý3ýý1 versus ýý6ýý4 integrin. J Biol Chem 286:7496-506
Drake, Justin M; Barnes, J Matthew; Madsen, Joshua M et al. (2010) ZEB1 coordinately regulates laminin-332 and {beta}4 integrin expression altering the invasive phenotype of prostate cancer cells. J Biol Chem 285:33940-8
Stipp, Christopher S (2010) Laminin-binding integrins and their tetraspanin partners as potential antimetastatic targets. Expert Rev Mol Med 12:e3