Bio-nanoparticles and bio-microfibers for improved gene transfer into glioma cells

Abstract

The investigation presented focused on strategic development of gene transfer vectors with the purpose of achieving boosted gene delivery performance in glioma cells and hopefully improving the current therapeutic efficacy of glioma tumors. On the one hand, nonviral magnetofection facilitates gene transfer by using a magnetic field to concentrate magnetic nanoparticle-associated plasmid delivery vectors onto target cells. In light of the well-established effects of the Tat peptide, a cationic cell-penetrating peptide, in enhancing the cytoplasmic delivery of a variety of cargos, we tested whether the combined use of magnetofection and Tat-mediated intracellular delivery would improve transfection efficiency. Through electrostatic interaction, bio-nanoparticles were formed by mixing polyethyleneimine-coated cationic magnetic iron beads with plasmid DNA, followed by addition of a bis(cysteinyl) histidine-rich Tat peptide. These ternary magnetofection complexes have significantly improved the gene transfer efficiencies both in vitro and in vivo. Moreover, the distribution of intrathecally injected bio-nanoparticles can be manipulated by external magnetic force suggesting the potential for localized gene delivery. We have also shown that bio-nanoparticles assembled through the interaction between polyethyleneimine-coated cationic magnetic iron beads and therapeutic baculoviruses could be a possible way to circumvent the problems of viral serum inactivation. On the other hand, we have established the fiber formation through self-assembly of polyelectrolytes comprising plasmid DNA and amphiphilic peptides. We have found that baculovirus particles can be encapsulated inside the fiber to form bio-microfibers which can protect baculovirus against serum complement inactivation. Our findings have suggested that the baculoviruses withhold their activity after emerging in the fiber. More importantly, the baculoviruses encapsulated inside the fiber have been shown to be resistant to human serum complement both in vitro and in vivo, which opens up a promising opportunity to realize the protection of baculovirus against serum inactivation during systemic administration.