We will test the hypothesis that cellular interaction with cryptic collagen epitopes play unique roles in regulating tumor growth and angiogenesis.
The aims of this proposal are based on experiments with two novel reagents that selectively bind cryptic epitopes within collagen-IV. Proteolytic remodeling of the extracellular matrix (ECM) plays important roles in angiogenesis and tumor growth. However, little is known concerning the mechanisms by which these cryptic ECM epitopes function. Our studies have identified the HUIV26 cryptic epitope that regulates endothelial and tumor cell adhesion and migration in vitro and angiogenesis and tumor growth in vivo. Interestingly, cellular interactions with denatured collagen-IV can be partially inhibited by antagonists of avb3 or Mab HUIV26. Antagonists of b1 integrins can also partially inhibit interactions while a combination of both avb3 and b1 antagonists completely inhibit cellular interactions with denatured collagen-IV. These observations suggest that at least one other cryptic epitope, in addition to the HUIV26 cryptic site is exposed within denatured collagen-IV. Our new studies suggest that a second cryptic epitope recognized by a synthetic peptide is exposed within the denatured collagen-IV. Blocking interactions with this second cryptic epitope may inhibit adhesion, migration and proliferation. Taken together, our studies suggest that at least two distinct cryptic epitopes recognized by different integrin receptors are present within collagen type-IV and that these epitopes may represent novel therapeutic targets for the treatment of malignant tumors. Based on our findings, the studies were designed to examine four central objectives. First, we will define the amino acid sequence of the HUIV26 cryptic epitope and examine potential mechanisms by which this epitope regulates TSP-1. Second, we will determine the functional consequences of interactions with the second cryptic epitope have on invasive cellular behavior in vitro and identify receptors for the second cryptic epitope and examine mechanisms by which interactions with this epitope regulates cellular behavior. Third, we will determine whether soluble forms of the cryptic epitope are released in the circulation and whether these soluble forms correlate with tumor progression Finally, we will determine whether the second cryptic epitope plays a role in angiogenesis, tumor growth and metastasis in vivo. These studies may result in the development of novel strategies for the treatment of human tumors.

National Institute of Health (NIH)
National Cancer Institute (NCI)
Research Project (R01)
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Tumor Progression and Metastasis Study Section (TPM)
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Snyderwine, Elizabeth G
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Maine Medical Center
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Caron, Jennifer M; Ames, Jacquelyn J; Contois, Liangru et al. (2016) Inhibition of Ovarian Tumor Growth by Targeting the HU177 Cryptic Collagen Epitope. Am J Pathol 186:1649-61
Ames, Jacquelyn J; Contois, Liangru; Caron, Jennifer M et al. (2016) Identification of an Endogenously Generated Cryptic Collagen Epitope (XL313) That May Selectively Regulate Angiogenesis by an Integrin Yes-associated Protein (YAP) Mechano-transduction Pathway. J Biol Chem 291:2731-50
Young, Kira; Tweedie, Eric; Conley, Barbara et al. (2015) BMP9 Crosstalk with the Hippo Pathway Regulates Endothelial Cell Matricellular and Chemokine Responses. PLoS One 10:e0122892
Contois, Liangru W; Akalu, Abebe; Caron, Jennifer M et al. (2015) Inhibition of tumor-associated ?v?3 integrin regulates the angiogenic switch by enhancing expression of IGFBP-4 leading to reduced melanoma growth and angiogenesis in vivo. Angiogenesis 18:31-46
Favreau, Amanda J; Vary, Calvin P H; Brooks, Peter C et al. (2014) Cryptic collagen IV promotes cell migration and adhesion in myeloid leukemia. Cancer Med 3:265-72
Duarte, Christine W; Murray, Kimberly; Lucas, F Lee et al. (2014) Improved survival outcomes in cancer patients with hereditary hemorrhagic telangiectasia. Cancer Epidemiol Biomarkers Prev 23:117-125
Gong, Yan; Yang, Xuehui; He, Qing et al. (2013) Sprouty4 regulates endothelial cell migration via modulating integrin *3 stability through c-Src. Angiogenesis 16:861-75
Contois, Liangru W; Nugent, Desiree P; Caron, Jennifer M et al. (2012) Insulin-like growth factor binding protein-4 differentially inhibits growth factor-induced angiogenesis. J Biol Chem 287:1779-89
Romero, Diana; O'Neill, Christine; Terzic, Aleksandra et al. (2011) Endoglin regulates cancer-stromal cell interactions in prostate tumors. Cancer Res 71:3482-93
Hamilton, Heather K; Rose, Amy E; Christos, Paul J et al. (2010) Increased shedding of HU177 correlates with worse prognosis in primary melanoma. J Transl Med 8:19

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