title: A Double-Switch Cell Fusion-Inducible Transgene Expression System for Neural Stem Cell-Based Antiglioma Gene Therapy.
abstract: Recent progress in neural stem cell- (NSC-) based tumor-targeted gene therapy showed that NSC vectors expressing an artificially engineered viral fusogenic protein, VSV-G H162R, could cause tumor cell death specifically under acidic tumor microenvironment by syncytia formation; however, the killing efficiency still had much room to improve. In the view that coexpression of another antitumoral gene with VSV-G can augment the bystander effect, a synthetic regulatory system that triggers transgene expression in a cell fusion-inducible manner has been proposed. Here we have developed a double-switch cell fusion-inducible transgene expression system (DoFIT) to drive transgene expression upon VSV-G-mediated NSC-glioma cell fusion. In this binary system, transgene expression is coregulated by a glioma-specific promoter and targeting sequences of a microRNA (miR) that is highly expressed in NSCs but lowly expressed in glioma cells. Thus, transgene expression is "switched off" by the miR in NSC vectors, but after cell fusion with glioma cells, the miR is diluted and loses its suppressive effect. Meanwhile, in the syncytia, transgene expression is "switched on" by the glioma-specific promoter. Our in vitro and in vivo experimental data show that DoFIT successfully abolishes luciferase reporter gene expression in NSC vectors but activates it specifically after VSV-G-mediated NSC-glioma cell fusion.
authors.affiliation: Key Laboratory for Major Obstetric Diseases of Guangdong Province, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou 510150, China.
authors.forename: Yumei
authors.initials: Y
authors.lastname: Luo
authors.affiliation: Key Laboratory for Major Obstetric Diseases of Guangdong Province, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou 510150, China ; Department of Biological Sciences, National University of Singapore, Singapore 117543 ; Institute of Bioengineering and Nanotechnology, Singapore 138669.
authors.forename: Detu
authors.identifier: 0000-0002-9268-1012
authors.initials: D
authors.lastname: Zhu
authors.affiliation: Department of Biological Sciences, National University of Singapore, Singapore 117543 ; Institute of Bioengineering and Nanotechnology, Singapore 138669.
authors.forename: Dang Hoang
authors.initials: DH
authors.lastname: Lam
authors.affiliation: Department of General Surgery, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou 510150, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Huang
authors.affiliation: Department of General Surgery, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou 510150, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Tang
authors.affiliation: Department of General Surgery, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou 510150, China.
authors.forename: Xitu
authors.initials: X
authors.lastname: Luo
authors.affiliation: Department of Biological Sciences, National University of Singapore, Singapore 117543 ; Institute of Bioengineering and Nanotechnology, Singapore 138669.
authors.forename: Shu
authors.initials: S
authors.lastname: Wang