Cholesterol‐conjugated PEGylated PAMAM as an efficient nanocarrier for plasmid encoding interleukin‐12 immunogene delivery toward colon cancer cells

Abstract

IL‐12 is a pleiotropic cytokine, which shows an ideal applicant for tumor immunotherapy, because of its features of creating an interconnection between innate (NK cells) and adaptive (cytotoxic T lymphocyte) immunity. IL‐12 gene therapy is a useful technique to deliver an immune‐modulatory gene directly into tumor site thereby limiting the adverse effects of systemic administration of IL‐12 proteins. One of the most largely investigated non‐viral gene carriers is polyamidoamine (PAMAM). In the current research, 5 and 3% of PAMAM primary amines were substituted to transmit the plasmid encoding IL‐12 gene to cells by cholesteryl chloroformate and alkyl‐PEG, respectively. The features of modified PAMAMs containing size and surface charge density, cytotoxicity, and transfection efficiency were investigated in colon cancer cells. in vitro experiment showed that this modified carrier with average size of about 160 nm and zeta potential of 30 mV was able to increase the level of IL‐12 production up to two folds as compared to that of the unmodified PAMAM. Improvement of the polymer hydrophobic balance along with of the modulation of the surface positive charge could provide an efficient and safe non‐viral IL‐12 gene for colon cancer immunogene therapy.

Evaluation of the efficiency of modified PAMAM dendrimer with low molecular weight protamine peptide to deliver IL ‐12 plasmid into stem cells as cancer therapy vehicles

“…The results of GFP transfection showed that PA‐Al and PA‐Al‐Pe at all studied C/P ratios revealed significant improvement in the efficiency of transfection, compared to PAMAM and PA‐Pe. In previous studies, hydrophobic modifications of PAMAM dendrimers resulted in improved delivery which may mainly be due to hydrophobic–hydrophilic balance in the structure of denderimer 2,31 …”

“…In previous studies, hydrophobic modifications of PAMAM dendrimers resulted in improved delivery which may mainly be due to hydrophobichydrophilic balance in the structure of denderimer. 2,31 Different types of peptides, including cell-penetrating peptides (CPP), cationic peptides, amphiphilic peptides and fusogenetic peptides are currently being used in gene transfer systems. Compared to proteins, peptides are more attractive for gene delivery purposes, due to the cost-effectiveness, smaller size, and lower immunogenicity.…”

“…In previous studies, hydrophobic modifications of PAMAM dendrimers resulted in improved delivery which may mainly be due to hydrophobichydrophilic balance in the structure of denderimer. 2,31 Different types of peptides, including cell-penetrating peptides (CPP), cationic peptides, amphiphilic peptides and fusogenetic CPP. 33 Several studies proposed that LMWP might act as a non-toxic and biocompatible gene carrier.…”

“…Interleukin 12 (IL‐12) has crucial roles in innate and adaptive immune systems against cancer cells, mainly through the production of Interferon gamma (IFN‐γ) and reducing the level of vascular endothelial growth factor (VEGF) expression and metalloproteinases 1 . However, systemic administration of IL‐12 protein has been hurdled because of its short half‐life, poor pharmacokinetics and cytotoxicity 2 . Recently, gene therapy has been considered as a promising strategy for treatment of human cancers 3,4 .…”

Recent advances of dendrimer in targeted delivery of drugs and genes to stem cells as cellular vehicles

“…Dendrimers have a variety of applications in biomedicine such as being used as carriers of drugs and genes, 27,28 as well as imaging and diagnostic agents. Therefore, dendrimers have to fulfill certain biological demands including high safety, negligible immunogenicity, being able to pass through barriers such as the blood–tissue barrier and cell membranes, high clinical efficiency due to prolonged stability in circulation, and being targetable toward specific cells and tissues 29–32 .…”