Article

A Novel Model for Evaluating Therapies Targeting Human Tumor Vasculature and Human Cancer Stem-like Cells

Hematology/Oncology, Internal Medicine, University of Michigan Medical Center.
Cancer Research (Impact Factor: 9.33). 04/2013; 73(12). DOI: 10.1158/0008-5472.CAN-12-2845
Source: PubMed

ABSTRACT

Human tumor vessels express tumor vascular markers (TVMs), proteins that are not expressed in normal blood vessels. Antibodies targeting TVMs could act as potent therapeutics. Unfortunately, preclinical in vivo studies testing anti-human TVM therapies have been difficult to perform due to a lack of in vivo models with confirmed expression of human TVMs. We therefore evaluated TVM expression in a human embryonic stem cell derived teratoma (hESCT) tumor model previously shown to have human vessels. We now report that, in the presence of tumor cells, hESCT tumor vessels express human TVMs. The addition of mouse embryonic fibroblasts and human tumor endothelial cells significantly increases the number of human tumor vessels. TVM induction is mostly tumor type specific with ovarian cancer cells inducing primarily ovarian TVMs while breast cancer cells induce breast cancer specific TVMs. We demonstrate the utility of this model to test an anti-human specific TVM immunotherapeutics; anti-human Thy-1 TVM immunotherapy results in central tumor necrosis and a three-fold reduction in human tumor vascular density. Finally, we tested the ability of the hESCT model, with human tumor vascular niche, to enhance the engraftment rate of primary human ovarian cancer stem-like cells (CSC). ALDH+ CSC from patients (n=6) engrafted in hESCT within 4-12 weeks whereas none engrafted in the flank. ALDH- ovarian cancer cells showed no engraftment in the hESCT or flank (n=3). Thus this model represents a useful tool to test anti-human TVM therapy and evaluate in vivo human CSC tumor biology.

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Available from: Maty Tzukerman, Jan 06, 2016
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    • "Cells from human ovarian cancer cell lines (A2780 and OVCAR8), human ascites, or primary ovarian tumors were processed and prepared as previously reported [35]. Cells were incubated with monoclonal antihuman VEGF R3-PE (R&D Systems, Minneapolis, MN) and CD133/2 (Allophycocyanin [APC]-tagged; Miltenyi Biotec, Gladbach, Germany) or for isotype control with Mouse IgG 2A APC and Mouse IgG 2A phycoerythrin (PE) (R&D Systems) and then ALDEFLUOR (Stemcell Technologies, Vancouver, Canada) as previously described [36]. Results were analyzed using Summit 6.0 (Beckman-Coulter, La Brea, CA). "
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    • "Cells from human ovarian cancer cell lines (A2780 and OVCAR8), human ascites, or primary ovarian tumors were processed and prepared as previously reported [35]. Cells were incubated with monoclonal antihuman VEGF R3-PE (R&D Systems, Minneapolis, MN) and CD133/2 (Allophycocyanin [APC]-tagged; Miltenyi Biotec, Gladbach, Germany) or for isotype control with Mouse IgG 2A APC and Mouse IgG 2A phycoerythrin (PE) (R&D Systems) and then ALDEFLUOR (Stemcell Technologies, Vancouver, Canada) as previously described [36]. Results were analyzed using Summit 6.0 (Beckman-Coulter, La Brea, CA). "
    [Show abstract] [Hide abstract]
    ABSTRACT: In ovarian cancer, loss of BRCA gene expression in tumors is associated with improved response to chemotherapy and increased survival. A means to pharmacologically downregulate BRCA gene expression could improve the outcomes of patients with BRCA wild-type tumors. We report that vascular endothelial growth factor receptor 3 (VEGFR3) inhibition in ovarian cancer cells is associated with decreased levels of both BRCA1 and BRCA2. Inhibition of VEGFR3 in ovarian tumor cells was associated with growth arrest. CD133+ ovarian cancer stemlike cells were preferentially susceptible to VEGFR3-mediated growth inhibition. VEGFR3 inhibition–mediated down-regulation of BRCA gene expression reversed chemotherapy resistance and restored chemosensitivity in resistant cell lines in which a BRCA2 mutation had reverted to wild type. Finally, we demonstrate that tumor-associated macrophages are a primary source of VEGF-C in the tumor microenvironment. Our studies suggest that VEGFR3 inhibition may be a pharmacologic means to downregulate BRCA genes and improve the outcomes of patients with BRCA wild-type tumors.
    Preview · Article · Jan 2014
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    • "Thus, the hESC-based model provides a crucial in vivo platform in view of the essential role of CSC self-renewal in the resistance to anti-cancer therapies and in rendering intratumoral heterogeneity amenable to biological analysis as well as anticancer therapy testing [5]. Furthermore, it was recently demonstrated that the hESC-based model express bona fide human tumor blood vessels and enhance tumor engraftment rate by primary human ovarian cancer stem-like cells (CSC) [37]. Accordingly, we aimed to examine the respective gene expression profiles of two different OCCC-derived CCSPs representing the extreme ends of the spectrum in terms of niche-dependent self-renewal versus tumorigenic differentiation. "
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