Ram Shankar, Marco Schmeer & Martin Schleef
Next Generation Vectors
Plasmid DNA is commonly used in vaccination, cell and gene therapy, and as a basic substance in viral vector and RNA production. Backbone sequences in a plasmid vector are only needed for amplification in bacterial cultures. Since the uncontrolled expression of these sequences may have profound detrimental effects, for example, the dissemination of antibiotic resistance genes, an important goal in vector development is to produce supercoiled DNA lacking such bacterial backbone sequences. One elegant approach is minicircle (MC) DNA, consisting almost only of (therapeutically) active gene cassette. Over the past few years, MCs have proven to be a reliable tool for efficient transgene expression in eukaryotic cells both in vitro and in vivo as well as for ex vivo modification for cell therapy or lately even for the generation of induced pluripotent stem cells. Recent trends and progress in pre-clinical studies suggest that the time has come for preparation of such minimalistic vectors to a High Quality Grade to enable for example the production of viral vectors for gene therapy. Furthermore, significant developments in transfection efficiency of non-viral vectors suggest that GMP grade MCs conformant to regulatory guidelines would be needed in the near future for direct clinical applications. This article provides an overview of the advantages and drawbacks of different approaches to produce MC DNA, their applications, and finally describe current and future developments.
Submitted for review: Feb 28 2017 Published: June 6 2017
Citation: Cell Gene Therapy Insights 2017;3(2), 285-300.