title: Epithelial ovarian cancer stem-like cells expressing α-gal epitopes increase the immunogenicity of tumor associated antigens.
abstract: BACKGROUND
  As ovarian cancer stem cells (CSCs) are responsible for tumor initiation, invasion, metastasis, and chemo-resistance, new stratagems that selectively target ovarian CSCs are critically significant. Our previous work have demonstrated that ovarian cancer spheroid cells are tumorigenic and chemo-resistant, and have the properties of ovarian CSCs. Herein, we hypothesized that expressing α-gal epitopes on ovarian spheroid cells may help eliminate CSCs and improve the outcome of therapeutic intervention for ovarian cancer patients.
  
  
  METHODS
  Lentivirus-mediated transfer of a pig α(1,3)galactosyltransferase [α1,3GT] enzyme gene into human ovarian cell line SKOV3 cells formed α-gal epitope-expressing cells (SKOV3-gal cells), and then these cells were maintained in a serum-free culture system to form SKOV3-gal spheroid cells. Efficacy of this cell vaccine was demonstrated in α1,3GT knockout mice (α1,3GT KO mice).
  
  
  RESULTS
  The antibody titers to α-gal epitopes measured by ELISA were significantly increased in α1,3GT KO mice after immunization with SKOV3-gal spheroid cells. Furthermore, compared with the non-immunized KO mice, the SKOV3 tumors grafted under renal capsules of KO mice immunized with SKOV3-gal spheroid cells grew slower and began to shrink on day 12. Western blot analysis also showed that immunized KO mice can produce effective antibody against certain tumor associated antigens (TAAs) derived from both SKOV3 cells and SKOV3 spheroid cells. The TAAs were further investigated by mass spectrometry and RNA interference (RNAi) technology. The results suggested that antibodies responding to protein c-erbB-2 may be raised in the sera of the mice after immunization with SKOV3-gal spheroid cells. Ultimately, vaccination with SKOV3-gal spheroid cells induced more CD3+CD4+T cells in the spleen of immunized mice than non-immunized KO mice.
  
  
  CONCLUSIONS
  The results suggest that vaccination using ovarian cancer stem-like cells engineered to express α-gal epitopes may be a novel strategy for treatment of ovarian cancer.
authors.affiliation: The Center of Research Laboratory, and Department of Gynecology, The International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China. yaoxf89@126.com.
authors.forename: Xiaofen
authors.initials: X
authors.lastname: Yao
authors.affiliation: The Center of Research Laboratory, and Department of Gynecology, The International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China. kabeng@126.com.
authors.forename: Zhangli
authors.initials: Z
authors.lastname: Dong
authors.affiliation: The Center of Research Laboratory, and Department of Gynecology, The International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China. 10111010022@fudan.edu.cn.
authors.forename: Qiuwan
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: The Center of Research Laboratory, and Department of Gynecology, The International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China. paulia@163.com.
authors.forename: Qian
authors.initials: Q
authors.lastname: Wang
authors.affiliation: The Center of Research Laboratory, and Department of Gynecology, The International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China. laidongmei@hotmail.com.
authors.forename: Dongmei
authors.initials: D
authors.lastname: Lai
mesh_terms: D000818:Animals; D000951:Antigens, Neoplasm / Q000276:immunology*; D015153:Blotting, Western; D019496:Cancer Vaccines / Q000276:immunology*; D000077216:Carcinoma, Ovarian Epithelial; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000276:immunology; D005260:Female; D005434:Flow Cytometry; D005700:Galactosyltransferases / Q000276:immunology*; D006801:Humans; D013058:Mass Spectrometry; D051379:Mice; D018345:Mice, Knockout; D008819:Mice, Nude; D009375:Neoplasms, Glandular and Epithelial / Q000276:immunology*; D014411:Neoplastic Stem Cells / Q000276:immunology*; D010051:Ovarian Neoplasms / Q000276:immunology*; D034741:RNA, Small Interfering; D060888:Real-Time Polymerase Chain Reaction; D018874:Spheroids, Cellular / Q000276:immunology; D013552:Swine; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D000951:Antigens, Neoplasm; D019496:Cancer Vaccines; D000939:Epitopes; D034741:RNA, Small Interfering; D005700:Galactosyltransferases; C047006:N-acetyllactosaminide alpha-1,3-galactosyltransferase