@article{BekesFriedlKoehleretal.2016,
  author    = {Bekes, Inga and Friedl, Thomas W. P. and K{\"o}hler, Tanja and M{\"o}bus, Volker and Janni, Wolfgang and W{\"o}ckel, Achim and Wulff, Christine},
  title     = {Does VEGF facilitate local tumor growth and spread into the abdominal cavity by suppressing endothelial cell adhesion, thus increasing vascular peritoneal permeability followed by ascites production in ovarian cancer?},
  series = {Molecular Cancer},
  volume    = {15},
  journal   = {Molecular Cancer},
  number    = {13},
  doi       = {10.1186/s12943-016-0497-3},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-169298},
  year      = {2016},
  abstract  = {Background Ovarian cancer is mostly associated with pathologically regulated permeability of peritoneal vessels, leading to ascites. Here, we investigated the molecular regulation of endothelial permeability by the vascular endothelial growth factor (VEGF) and both tight and adherens junction proteins (VE-cadherin and claudin 5) with regards to the tumor biology of different ovarian cancer types. Methods Serum and ascites samples before and after surgery, as well as peritoneal biopsies of 68 ovarian cancer patients and 20 healthy controls were collected. In serum and ascites VEGF protein was measured by ELISA. In peritoneal biopsies co-localization of VE-cadherin and claudin 5 was investigated using immunohistochemical dual staining. In addition, the gene expression of VE-cadherin and claudin 5 was quantified by Real-time PCR. Differences in VEGF levels, VE-cadherin and claudin 5 gene expression were analyzed in relation to various tumor characteristics (tumor stage, grading, histological subtypes, resection status after surgery) and then compared to controls. Furthermore, human primary ovarian cancer cells were co-cultured with human umbilical vein endothelial cells (HUVEC) and changes in VE-cadherin and claudin 5 were investigated after VEGF inhibition. Results VEGF was significantly increased in tumor patients in comparison to controls and accumulates in ascites. The highest VEGF levels were found in patients diagnosed with advanced tumor stages, with tumors of poor differentiation, or in the group of solid / cystic-solid tumors. Patients with residual tumor after operation showed significantly higher levels of VEGF both before and after surgery as compared to tumor-free resected patients. Results of an immunohistochemical double-staining experiment indicated co-localization of VE-cadherin and claudin 5 in the peritoneal vasculature. Compared to controls, expression of VE-cadherin and claudin 5 was significantly suppressed in peritoneal vessels of tumor patients, but there were no significant differences regarding VE-cadherin and claudin 5 expression in relation to different tumor characteristics. A significant positive correlation was found between VE-cadherin and claudin 5 expression. VEGF inhibition in vitro was associated with significant increase in VE-cadherin and claudin 5. Conclusions Our results indicate that increased peritoneal permeability in ovarian cancer is due to down-regulation of adhesion proteins via tumor derived VEGF. Advanced ovarian cancer with aggressive tumor biology may be associated with early dysregulation of vascular permeability leading to ascites. These patients may benefit from therapeutic VEGF inhibition.},
  language  = {en}
}
@article{MontalbandelBarrioPenskiSchlahsaetal.2016,
  author    = {Montalb{\´a}n del Barrio, Itsaso and Penski, Cornelia and Schlahsa, Laura and Stein, Roland G. and Diessner, Joachim and W{\"o}ckel, Achim and Dietl, Johannes and Lutz, Manfred B. and Mittelbronn, Michel and Wischhusen, J{\"o}rg and H{\"a}usler, Sebastian F. M.},
  title     = {Adenosine-generating ovarian cancer cells attract myeloid cells which differentiate into adenosine-generating tumor associated macrophages - a self-amplifying, CD39- and CD73-dependent mechanism for tumor immune escape},
  series = {Journal for ImmunoTherapy of Cancer},
  volume    = {4},
  journal   = {Journal for ImmunoTherapy of Cancer},
  number    = {49},
  doi       = {10.1186/s40425-016-0154-9},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-146624},
  year      = {2016},
  abstract  = {Background Ovarian cancer (OvCA) tissues show abundant expression of the ectonucleotidases CD39 and CD73 which generate immunomodulatory adenosine, thereby inhibiting cytotoxic lymphocytes. Little, however, is known about the effect of adenosine on myeloid cells. Considering that tumor associated macrophages (TAM) and myeloid-derived suppressor cells (MDSC) constitute up to 20 \% of OvCA tissue, we investigated the effect of adenosine on myeloid cells and explored a possible contribution of myeloid cells to adenosine generation in vitro and ex vivo. Methods Monocytes were used as human blood-derived myeloid cells. After co-incubation with SK-OV-3 or OAW-42 OvCA cells, monocyte migration was determined in transwell assays. For conversion into M2-polarized "TAM-like" macrophages, monocytes were co-incubated with OAW-42 cells. Ex vivo TAMs were obtained from OvCA ascites. Macrophage phenotypes were investigated by intracellular staining for IL-10 and IL-12. CD39 and CD73 expression were assessed by FACS analysis both on in vitro-induced TAM-like macrophages and on ascites-derived ex situ-TAMs. Myeloid cells in solid tumor tissue were analyzed by immunohistochemistry. Generation of biologically active adenosine by TAM-like macrophages was measured in luciferase-based reporter assays. Functional effects of adenosine were investigated in proliferation-experiments with CD4+ T cells and specific inhibitors. Results When CD39 or CD73 activity on OvCA cells were blocked, the migration of monocytes towards OvCA cells was significantly decreased. In vivo, myeloid cells in solid ovarian cancer tissue were found to express CD39 whereas CD73 was mainly detected on stromal fibroblasts. Ex situ-TAMs and in vitro differentiated TAM-like cells, however, upregulated the expression of CD39 and CD73 compared to monocytes or M1 macrophages. Expression of ectonucleotidases also translated into increased levels of biologically active adenosine. Accordingly, co-incubation with these TAMs suppressed CD4+ T cell proliferation which could be rescued via blockade of CD39 or CD73. Conclusion Adenosine generated by OvCA cells likely contributes to the recruitment of TAMs which further amplify adenosine-dependent immunosuppression via additional ectonucleotidase activity. In solid ovarian cancer tissue, TAMs express CD39 while CD73 is found on stromal fibroblasts. Accordingly, small molecule inhibitors of CD39 or CD73 could improve immune responses in ovarian cancer.},
  language  = {en}
}