title: Human anti-CAIX antibodies mediate immune cell inhibition of renal cell carcinoma in vitro and in a humanized mouse model in vivo.
abstract: BACKGROUND
  Carbonic anhydrase (CA) IX is a surface-expressed protein that is upregulated by the hypoxia inducible factor (HIF) and represents a prototypic tumor-associated antigen that is overexpressed on renal cell carcinoma (RCC). Therapeutic approaches targeting CAIX have focused on the development of CAIX inhibitors and specific immunotherapies including monoclonal antibodies (mAbs). However, current in vivo mouse models used to characterize the anti-tumor properties of fully human anti-CAIX mAbs have significant limitations since the role of human effector cells in tumor cell killing in vivo is not directly evaluated.
  
  
  METHODS
  The role of human anti-CAIX mAbs on CAIX(+) RCC tumor cell killing by immunocytes or complement was tested in vitro by antibody-dependent cell-mediated cytotoxicity (ADCC), complement-dependent cytotoxicity (CDC) and antibody-dependent cellular phagocytosis (ADCP) as well as on CAIX(+) RCC cellular motility, wound healing, migration and proliferation. The in vivo therapeutic activity mediated by anti-CAIX mAbs was determined by using a novel orthotopic RCC xenograft humanized animal model and analyzed by histology and FACS staining.
  
  
  RESULTS
  Our studies demonstrate the capacity of human anti-CAIX mAbs that inhibit CA enzymatic activity to result in immune-mediated killing of RCC, including nature killer (NK) cell-mediated ADCC, CDC, and macrophage-mediated ADCP. The killing activity correlated positively with the level of CAIX expression on RCC tumor cell lines. In addition, Fc engineering of anti-CAIX mAbs was shown to enhance the ADCC activity against RCC. We also demonstrate that these anti-CAIX mAbs inhibit migration of RCC cells in vitro. Finally, through the implementation of a novel orthotopic RCC model utilizing allogeneic human peripheral blood mononuclear cells in NOD/SCID/IL2Rγ(-/-) mice, we show that anti-CAIX mAbs are capable of mediating human immune response in vivo including tumor infiltration of NK cells and activation of T cells, resulting in inhibition of CAIX(+) tumor growth.
  
  
  CONCLUSIONS
  Our findings demonstrate that these novel human anti-CAIX mAbs have therapeutic potential in the unmet medical need of targeted killing of HIF-driven CAIX(+)RCC. The orthotopic tumor xenografted humanized mouse provides an improved model to evaluate the in vivo anti-tumor capabilities of fully human mAbs for RCC therapy.
authors.affiliation: Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, 450 Brookline Ave., Boston, MA, USA. De-Kuan_Chang@dfci.harvard.edu.|Department of Medicine, Harvard Medical School, 25 Shattuck Street, Boston, MA, USA. De-Kuan_Chang@dfci.harvard.edu.
authors.forename: De-Kuan
authors.initials: DK
authors.lastname: Chang
authors.affiliation: Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, 450 Brookline Ave., Boston, MA, USA. raymond.moniz@merck.com.|Department of Medicine, Harvard Medical School, 25 Shattuck Street, Boston, MA, USA. raymond.moniz@merck.com.
authors.forename: Raymond J
authors.initials: RJ
authors.lastname: Moniz
authors.affiliation: Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, 450 Brookline Ave., Boston, MA, USA. xu.zhongyao@sinopath.cn.
authors.forename: Zhongyao
authors.initials: Z
authors.lastname: Xu
authors.affiliation: Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, 450 Brookline Ave., Boston, MA, USA. Jiusong_Sun@DFCI.HARVARD.EDU.|Department of Medicine, Harvard Medical School, 25 Shattuck Street, Boston, MA, USA. Jiusong_Sun@DFCI.HARVARD.EDU.
authors.forename: Jiusong
authors.initials: J
authors.lastname: Sun
authors.affiliation: Department of Medical Oncology, Dana-Farber Cancer Institute, 450 Brookline Ave., Boston, MA, USA. SSIGNORETTI@PARTNERS.ORG.|Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA. SSIGNORETTI@PARTNERS.ORG.
authors.forename: Sabina
authors.initials: S
authors.lastname: Signoretti
authors.affiliation: Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, 450 Brookline Ave., Boston, MA, USA. Quan_Zhu@dfci.harvard.edu.|Department of Medicine, Harvard Medical School, 25 Shattuck Street, Boston, MA, USA. Quan_Zhu@dfci.harvard.edu.
authors.forename: Quan
authors.initials: Q
authors.lastname: Zhu
authors.affiliation: Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, 450 Brookline Ave., Boston, MA, USA. wayne_marasco@dfci.harvard.edu.|Department of Medicine, Harvard Medical School, 25 Shattuck Street, Boston, MA, USA. wayne_marasco@dfci.harvard.edu.
authors.forename: Wayne A
authors.initials: WA
authors.lastname: Marasco
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D000920:Antibody-Dependent Cell Cytotoxicity / Q000187:drug effects; D000951:Antigens, Neoplasm / Q000276:immunology*; D000071231:Carbonic Anhydrase IX; D002256:Carbonic Anhydrases / Q000276:immunology*; D002292:Carcinoma, Renal Cell / Q000276:immunology* / Q000473:pathology; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D004195:Disease Models, Animal; D004705:Endocytosis / Q000187:drug effects; D006801:Humans; D007680:Kidney Neoplasms / Q000276:immunology* / Q000473:pathology; D007694:Killer Cells, Natural / Q000187:drug effects / Q000276:immunology; D008214:Lymphocytes / Q000187:drug effects / Q000276:immunology*; D051379:Mice; D015202:Protein Engineering; D057127:Single-Chain Antibodies / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D057127:Single-Chain Antibodies; C089226:CA9 protein, human; D000071231:Carbonic Anhydrase IX; D002256:Carbonic Anhydrases