2 research outputs found
Tuning Surface Charge and PEGylation of Biocompatible Polymers for Efficient Delivery of Nucleic Acid or Adenoviral Vector
As an effective and safe strategy
to overcome the limits of therapeutic
nucleic acid or adenovirus (Ad) vectors for in vivo application, various
technologies to modify the surface of vectors with nonimmunogenic/biocompatible
polymers have been emerging in the field of gene therapy. However,
the transfection efficacy of the polymer to transfer genetic materials
is still relatively weak. To develop more advanced and effective polymers
to deliver not only Ad vectors, but also nucleic acids, 6 biocompatible
polymers were newly designed and synthesized to different sizes (2k,
3.4k, or 5k) of poly(ethylene) glycol (PEG) and different numbers
of amine groups (2 or 5) based on methoxy poly(ethylene glycol)-<i>b</i>-poly{<i>N</i>-[<i>N</i>-(2-aminoethyl)-2-aminoethyl]-l-glutamate (PNLG). We characterized size distribution and surface
charge of 6 PNLGs after complexation with either nucleic acid or Ad.
Among all 6 PNLGs, the 5 amine group PNLG showed the strongest efficacy
in delivering nucleic acid as well as Ad vectors. Interestingly, cellular
uptake results showed higher uptake ability in Ad complexed with 2
amine group PNLG than Ad/5 amine group PNLG, suggesting that the size
of Ad/PNLGs is more essential than the surface charge for cellular
uptake in polymers with charges greater than 30 mV. Moreover, the
endosome escape ability of Ad/PNLGs increased depending on the number
of amine groups, but decreased by PEG size. Cancer cell killing efficacy
and immune response studies of oncolytic Ad/PNLGs showed 5 amine group
PNLG to be a more effective and safe carrier for delivering Ad. Overall,
these studies provide new insights into the functional mechanism of
polymer-based approaches to either nucleic acid or Ad/nanocomplex.
Furthermore, the identified ideal biocompatible PNLG polymer formulation
(5 amine/2k PEG for nucleic acid, 5 amine/5k PEG for Ad) demonstrated
high transduction efficiency as well as therapeutic value (efficacy
and safety) and thus has strong potential for in vivo therapeutic
use in the future
Safety Profiles and Antitumor Efficacy of Oncolytic Adenovirus Coated with Bioreducible Polymer in the Treatment of a CAR Negative Tumor Model
Adenovirus
(Ad) vectors show promise as cancer gene therapy delivery
vehicles, but immunogenic safety concerns and coxsackie and adenovirus
receptor (CAR)-dependency have limited their use. Alternately, biocompatible
and bioreducible nonviral vectors, including arginine-grafted cationic
polymers, have been shown to deliver nucleic acids through a cell
penetration peptide (CPP) and protein transduction domain (PTD) effect.
We utilized the advantages of both viral and nonviral vectors to develop
a hybrid gene delivery vehicle by coating Ad with mPEG-PEI-<i>g</i>-Arg-S-S-Arg-<b>g</b>-PEI-mPEG (Ad/PPSA). Characterization
of Ad/PPSA particle size and zeta potential showed an overall size
and cationic charge increase in a polymer concentration-dependent
manner. Ad/PPSA also showed a marked transduction efficiency increase
in both CAR-negative and -positive cells compared to naked Ad. Competition
assays demonstrated that Ad/PPSA produced higher transgene expression
levels than naked Ad and achieved CAR-independent transduction. Oncolytic
Ad (DWP418)/PPSA was able to overcome the nonspecificity of polymer-only
therapies by demonstrating cancer-specific killing effects. Furthermore,
the DWP418/PPSA nanocomplex elicited a 2.24-fold greater antitumor
efficacy than naked Ad in vivo. This was supported by immunohistochemical
confirmation of Ad E1As accumulation in MCF7 xenografted tumors. Lastly,
intravenous injection of DWP418/PPSA elicited less innate immune response
compared to naked Ad, evaluated by interleukin-6 cytokine release
into the serum. The increased antitumor effect and improved vector
targeting to both CAR-negative and -positive cells make DWP418/PPSA
a promising tool for cancer gene therapy