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Published on: February 22, 2015
A Double-Switch Cell Fusion-Inducible Transgene Expression System for Neural Stem Cell-Based Antiglioma Gene Therapy
Yumei Luo1, Detu Zhu2, Dang Hoang Lam3
1Key Laboratory for Major Obstetric Diseases of Guangdong Province, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou 510150, China.
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.
Insights
Neural stem cells engineered to express a fusogenic protein can target tumors. A new system, DoFIT, enhances this by controlling gene expression after cell fusion, improving tumor cell killing efficiency.
Area of Science:
- Biotechnology
- Molecular Biology
- Oncology
Background:
- Neural stem cells (NSCs) show promise in tumor-targeted gene therapy.
- Engineered viral fusogenic protein VSV-G H162R in NSCs can induce tumor cell death via syncytia formation in acidic tumor microenvironments.
- Improving the efficiency of this tumor-killing mechanism is crucial.
Purpose of the Study:
- To develop a novel synthetic regulatory system for enhanced tumor-targeted gene therapy.
- To create a double-switch cell fusion-inducible transgene expression system (DoFIT).
- To enable transgene expression specifically after NSC-glioma cell fusion.
Main Methods:
- Developed the DoFIT system, a binary system regulating transgene expression.
- Utilized a glioma-specific promoter and microRNA (miR) targeting sequences.
- Engineered NSC vectors to express VSV-G H162R and the DoFIT system.
- Validated DoFIT's function in vitro and in vivo using a luciferase reporter gene.
Main Results:
- DoFIT successfully suppressed reporter gene expression in NSC vectors.
- Reporter gene expression was specifically activated after VSV-G-mediated NSC-glioma cell fusion.
- The system demonstrated cell fusion-inducible transgene expression.
- Experimental data confirmed DoFIT's efficacy in both in vitro and in vivo models.
Conclusions:
- The DoFIT system effectively controls transgene expression in a cell fusion-inducible manner.
- This system enhances the specificity and potential efficacy of NSC-based tumor-targeted gene therapy.
- DoFIT offers a promising strategy for augmenting the bystander effect in cancer treatment.
