Introduction: Glioblastoma multiforme (GBM) is the most common and highly malignant primary brain tumor [1, 2]. In spite of the exciting effects caused by combined strategies composed of surgery, gene therapy, chemotherapy and radiotherapy, the prognosis for some patients with GBM remains poor. With regard to gene therapy, one of key problems is lack of effective and targeting vector. VTW is a peptide with especially high binding ability to U87 GBM cells. Here, we prepared a novel nanoparticle made by polymers which may solve the problem of targeting transfection into glioblastoma cells.
Methods: Polyethylenimine (PEI, 25 kDa) was activated by N-succinimidyl-3-(2-pyridyldithio)-propionate (SPDP) and PEI-PDP was got. Then VTW peptide with different concentrations was added into PEI-PDP liquid before or after PEI-PDP being mixed with plasmid, to make pre- or post-modified nanoparticles respectively. Particle size, zeta-potential, transmission electron microscopic image and agarose gel electrophoresis assay were evaluated to describe the nanoparticles. Transfection efficiency was investigated via fluorescent microscope and flow cytometry. Lipofectamine2000 and naked DNA were used as control.
Results: All the pre- and post-modified PEI nanoparticles augmented the transfection efficiency of U87 cells, but the latter was better. VTW modified PEI nanoparticles did not ameliorate transfection effect of the control cell lines. One of the post-modified nanoparticles (mole ratio: PEI/VTW=1/20) brought about the highest transfection efficiency among our polymers, even close to lipofectamine2000. Adding serum into transfection medium produced fewer influence to modified PEI nanoparticles compared with lipofectamine2000.
Conclusions: Vectors based on VTW peptide and PEI can improve gene transfection efficiency of U87 glioblastoma cells notably and specially. The ways of polymer conjugation and concentration of VTW peptides were vital factors influencing effect of nanoparticles.
Patient Care: After further modification and experiment, this gene carrier targeting GBM cells mediated by VTW perhaps can provide another possibility for GBM patients in future, to eliminate the intracranial residual malignant tumor intra- or post-surgery, safely and effectively.
Learning Objectives: By the conclusion of this session, participants should be able to learn: 1) This is the first demonstration of successful using the VTW peptide and PEI-based carrier for intracellular gene delivery of pDNA in a GBM cell-specific manner; 2) VTW peptide is an excellent target molecule for GBM cells and the nanoparticles made by VTW and polymers can lead to a special and effective transfection of GBM cells; 3) VTW-modified nanoparticles is one kind of promising vector which has a potential to improve therapeutic effect of modern strategies.