title: VEGF Potentiates GD3-Mediated Immunosuppression by Human Ovarian Cancer Cells.
abstract: OBJECTIVE
  Natural killer T (NKT) cells are important mediators of antitumor immune responses. We have previously shown that ovarian cancers shed the ganglioside GD3, which inhibits NKT-cell activation. Ovarian cancers also secrete high levels of VEGF. In this study, we sought to test the hypothesis that VEGF production by ovarian cancers suppresses NKT-cell-mediated antitumor responses.
  
  
  METHODS
  To investigate the effects of VEGF on CD1d-mediated NKT-cell activation, a conditioned media model was established, wherein the supernatants from ovarian cancer cell lines (OV-CAR-3 and SK-OV-3) were used to treat CD1d-expressing antigen-presenting cells (APC) and cocultured with NKT hybridomas. Ovarian cancer-associated VEGF was inhibited by treatment with bevacizumab and genistein; conditioned medium was collected, and CD1d-mediated NKT-cell responses were assayed by ELISA.
  
  
  RESULTS
  Ovarian cancer tissue and ascites contain lymphocytic infiltrates, suggesting that immune cells traffic to tumors, but are then inhibited by immunosuppressive molecules within the tumor microenvironment. OV-CAR-3 and SK-OV-3 cell lines produce high levels of VEGF and GD3. Pretreatment of APCs with ascites or conditioned medium from OV-CAR-3 and SK-OV-3 blocked CD1d-mediated NKT-cell activation. Inhibition of VEGF resulted in a concomitant reduction in GD3 levels and restoration of NKT-cell responses.
  
  
  CONCLUSIONS
  We found that VEGF inhibition restores NKT-cell function in an in vitro ovarian cancer model. These studies suggest that the combination of immune modulation with antiangiogenic treatment has therapeutic potential in ovarian cancer. Clin Cancer Res; 22(16); 4249-58. ©2016 AACR.
authors.affiliation: Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland.
authors.forename: Irina V
authors.initials: IV
authors.lastname: Tiper
authors.affiliation: Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland. Department of Gynecology and Obstetrics, The Kelly Gynecologic Oncology Service, The Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins School of Medicine, Baltimore, Maryland.
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Temkin
authors.affiliation: Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland.
authors.forename: Sarah
authors.initials: S
authors.lastname: Spiegel
authors.affiliation: Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland.
authors.forename: Simeon E
authors.initials: SE
authors.lastname: Goldblum
authors.affiliation: Department of Gynecology and Obstetrics, The Kelly Gynecologic Oncology Service, The Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins School of Medicine, Baltimore, Maryland.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Giuntoli
authors.affiliation: Department of Pathology, The Johns Hopkins School of Medicine, Baltimore, Maryland.
authors.forename: Mathias
authors.initials: M
authors.lastname: Oelke
authors.affiliation: Department of Pathology, The Johns Hopkins School of Medicine, Baltimore, Maryland.
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Schneck
authors.affiliation: Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland. twebb@som.umaryland.edu.
authors.forename: Tonya J
authors.initials: TJ
authors.lastname: Webb
mesh_terms: D017951:Antigen Presentation; D000938:Antigen-Presenting Cells / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D045744:Cell Line, Tumor; D017077:Culture Media, Conditioned / Q000494:pharmacology; D004357:Drug Synergism; D005260:Female; D005732:Gangliosides / Q000494:pharmacology*; D006801:Humans; D056747:Immunomodulation / Q000187:drug effects*; D007694:Killer Cells, Natural / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D008213:Lymphocyte Activation / Q000187:drug effects / Q000276:immunology; D055611:Natural Killer T-Cells / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D010051:Ovarian Neoplasms / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D059016:Tumor Microenvironment / Q000187:drug effects / Q000276:immunology; D042461:Vascular Endothelial Growth Factor A / Q000494:pharmacology*
chemical_list: D017077:Culture Media, Conditioned; D005732:Gangliosides; D042461:Vascular Endothelial Growth Factor A; C026226:ganglioside, GD3