Regulated ex vivo regional gene therapy for bone repair using an inducible caspase-9 suicide gene system

Sofia Bougioukli, Venus Vakhshori, Brandon Ortega, Osamu Sugiyama, Jay Lieberman

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


In order to adapt ex vivo regional gene therapy for clinical applications in orthopaedic surgery, safety issues must be considered. In this study we developed a suicide approach using a dual gene expression two step transcriptional amplification lentiviral vector (LV-TSTA) encoding BMP-2 and an inducible caspase 9 (iC9) system that selectively induces apoptosis upon activation with a chemical inducer of dimerization (CID). Transduction of rat bone marrow stromal cells (RBMSCs) with LV-TSTA-iC9/BMP-2 led to abundant BMP-2 production (90.3 ± 7.9 ng/24 h/106 cells) in vitro and stimulated bone formation in a mouse muscle pouch in the absence of CID. Moreover it was shown that CID could be used to selectively induce apoptosis in iC9-transduced cells both in vitro and in vivo. Double exposure to serial dilutions of CID decreased in vitro production of BMP-2 by 85–87% and Luc activity by 97–99% in iC9/BMP-2 or iC9/Luc-transduced cells respectively. Early administration of CID (Days 0–1 post-op) in mice implanted with iC9/BMP-2-transduced RBMSCs was effective in blocking bone formation, indicating that CID was toxic to the transduced cells. In iC9/Luc-implanted mice, late administration of two doses of CID (Days 27–28 post-op) significantly reduced the luciferase signal. The current study provides proof of concept for the potential clinical application of regulated gene therapy to promote bone repair.

Original languageEnglish (US)
Pages (from-to)230-239
Number of pages10
JournalGene therapy
Issue number6
StatePublished - Jun 1 2019
Externally publishedYes

Bibliographical note

Funding Information:
Acknowledgements This work was supported by a National Institutes of Health grant to JRL [R01AR057076]. The authors would like to thank Ryan Park and Ivetta Vorobyova of the USC Molecular Imaging Center for their invaluable contribution in microCT and in vivo bioluminescent imaging. We would also like to thank Amy Tang for the histology sections and staining. Finally, special thanks to Dr. David Spencer for his guidance on the iC9/CID system.

Publisher Copyright:
© 2019, Springer Nature Limited.


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