title: Chimeric 5/35 adenovirus-mediated Dickkopf-1 overexpression suppressed tumorigenicity of CD44⁺ gastric cancer cells via attenuating Wnt signaling.
abstract: BACKGROUND
  Gastric cancer stem cells (CSCs), which require activation of Wnt signaling to maintain their self-renewal and tumorigenicity, are proposed to be critical targets for effective therapy of gastric carcinomas. Gene therapies that are delivered by adenovirus of serotype 5 (Ad5) or chimeric 5/35(Ad5/35) adenovirus have shown promise for treating various cancers. Here we aimed to develop a gene therapy strategy that targeted gastric CSCs (CD44⁺ cells).
  
  
  METHODS
  CD44⁺ cells were isolated by fluorescence activated cell sorting from both primary gastric cancer cells and cell lines. Expression of adenovirus receptors was examined in CD44⁺ and CD44⁻ cells. A potent Wnt antagonist Dickkopf-1 (DKK1) was delivered into CD44⁺ cells using Ad5/35 (Ad5/35-DKK1). The therapeutic outcomes were evaluated.
  
  
  RESULTS
  Expression of Coxsakievirus adenovirus receptor for Ad5 was significantly reduced, while abundance of CD46, the receptor for Ad5/35, was slightly higher in CD44⁺ cells. Accordingly, CD44⁺ cells were sensitive to Ad5/35 infection, but not to Ad5. Ad5/35-DKK1 introduced DKK1 into CD44⁺ cells and deactivated endogenous Wnt/β-catenin signaling efficiently. Overexpression of DKK1 inhibited survival, anchorage-independent colony formation, and invasion of CD44⁺ cells, which were restored by a GSK-3 specific inhibitor BIO-acetoxime. More importantly, introduction of DKK1 abrogated the tumorigenicity of CD44⁺ cells in vivo. However, Ad5/35-DKK1 only showed minimal cytotoxicity to normal tissue-derived cells, L-02 and GES-1.
  
  
  CONCLUSIONS
  We developed, for the first time, a novel Ad5/35-DKK1-based approach to abrogate Wnt signaling in CSCs and demonstrated that gastric CSC-targeting gene therapy was effective in preclinical experiments.
authors.affiliation: Department of Gastroenterology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing 400042, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Wang
authors.forename: Jia
authors.initials: J
authors.lastname: Liu
authors.forename: Lei Na
authors.initials: LN
authors.lastname: Ma
authors.forename: Hua Liang
authors.initials: HL
authors.lastname: Xiao
authors.forename: Ya Zhou
authors.initials: YZ
authors.lastname: Wang
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Zhe
authors.initials: Z
authors.lastname: Wang
authors.forename: Linli
authors.initials: L
authors.lastname: Fan
authors.forename: Chunhui
authors.initials: C
authors.lastname: Lan
authors.forename: Min
authors.initials: M
authors.lastname: Yang
authors.forename: Lu
authors.initials: L
authors.lastname: Hu
authors.forename: Yanlin
authors.initials: Y
authors.lastname: Wei
authors.forename: Xiu Wu
authors.initials: XW
authors.lastname: Bian
authors.forename: Dongfeng
authors.initials: D
authors.lastname: Chen
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D062727:Coxsackie and Adenovirus Receptor-Like Membrane Protein / Q000235:genetics; D018390:Gene Targeting / Q000379:methods; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors; D006801:Humans; D018960:Hyaluronan Receptors / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics*; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D014411:Neoplastic Stem Cells / Q000378:metabolism*; D013274:Stomach Neoplasms / Q000473:pathology / Q000628:therapy*; D060449:Wnt Signaling Pathway / Q000235:genetics; D023041:Xenograft Model Antitumor Assays
chemical_list: D062727:Coxsackie and Adenovirus Receptor-Like Membrane Protein; C501126:DKK1 protein, human; D018960:Hyaluronan Receptors; D036341:Intercellular Signaling Peptides and Proteins