Cre Recombinase Mediates the Removal of Bacterial Backbone to Efficiently Generate rSV40

Xiaoxia Shi,Matthew Ryan Ykema,Jaco Hazenoot,Lysbeth Ten Bloemendaal,Irene Mancini,Machteld Odijk,Peter De Haan,Piter J Bosma

doi:10.1016/j.omtm.2018.02.010

Xiaoxia Shi, Matthew Ryan Ykema + Show 6 more

Open Access

https://doi.org/10.1016/j.omtm.2018.02.010

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Abstract

Gene therapy has been shown to be a feasible approach to treat inherited disorders in vivo. Among the currently used viral vector systems, adeno-associated virus (AAV) vectors are the most advanced and have been applied in patients successfully. An important drawback of non-integrating AAV vectors is their loss of expression upon cell division, while repeating systemic administration lacks efficacy due to the induction of neutralizing antibodies. In addition, a significant percentage of the general population is not eligible for AAV-mediated gene therapy due to pre-existing immunity. Development of additional viral vectors may overcome this hurdle. Simian virus 40 (SV40)-derived vectors have been reported to transduce different tissues, including the liver, and prevalence of neutralizing antibodies in the general population is very low. This renders recombinant SV40 (rSV40) vector an interesting candidate for effective (re-)administration. Clinical use of SV40 vectors is in part hampered by less advanced production methods compared to AAVs. To optimize the production of rSV40 and make it better suitable for clinical practice, we developed a production system that relies on Cre recombinase-mediated removal of the bacterial plasmid backbone.

Highlights

Recent clinical successes demonstrate that gene therapy is a novel and effective treatment option for inherited genetic disorders.[1,2,3,4] The choice of gene therapy vector depends on the tissue and disease targeted
The number of vector genomes produced by the Cre-mediated excision of the Simian virus 40 (SV40) genome from rSVLuc co-transfected with the Cre plasmid was comparable to that produced by the Not1-mediated excision of the recombinant SV40 (rSV40) genome from the rSVLucDLox-P plasmid (Figure 1A)
Many papers have reported the use of rSV40 vectors to treat inherited disorders in pre-clinical animal models.[30,37,38]

Summary

Introduction

Recent clinical successes demonstrate that gene therapy is a novel and effective treatment option for inherited genetic disorders.[1,2,3,4] The choice of gene therapy vector depends on the tissue and disease targeted. Natural exposure to AAV is frequently early in life, and it results in the prevalence of neutralizing antibodies toward AAV in a significant percentage of the general population.[14] This renders gene therapy treatment with AAV in a part of the patients suffering from an inherited liver disease ineffective. Developing therapeutic strategies to overcome this problem will allow treatment of these patients and of patients who have received a nontherapeutic vector dose in early phase studies

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Conclusion