Antisense oligonucleotides (AONs) are important tools for the specific modulation of gene expression. They are applied widely in the research laboratory for gene """"""""knockdown"""""""" studies, and they are being developed clinically as therapeutics for a wide range of indications. The major challenge to more widespread implementation of this technology is cellular delivery. While many polymers and lipids have been used, with varying degrees of success, to deliver oligonucleotides to cells, their efficiency is highly variable depending on factors such as the chemistry and structure of the ON, the cell type used and the presence/absence of serum. Furthermore, the biophysical basis for delivery efficiency is poorly understood, and so development of delivery vectors remains a largely empirical process. Over the past several years, our group has pioneered a quantitative, engineering approach to oligonucleotide delivery. We have devoted considerable effort to identifying and quantifying the major barriers to cellular delivery and to developing relationships between the biophysics of polymer-oligonucleotide interactions and the extent and dynamics of antisense activity. Our work has highlighted the role of endosomal escape as a limiting cellular factor and competitive polyelectrolyte dissociation of polymer-oligonucleotide complexes as a major molecular biophysical factor governing antisense activity. We have found that the pH-sensitive polymer, poly(propylacrylic acid), PPAA, is able to mediate endosomal escape and improve delivery of AONs in conjunction with the cationic lipid, DOTAP. More recently, we have extended this concept to create novel graft copolymers that improve antisense-mediated gene silencing in the presence of serum. Our very promising Preliminary Results were based on a single composition of ethylene oxide/propylene oxide groups in the poly (oxyalkylene amine) grafted onto PPAA. In the proposed work, we will synthesize additional polymers that will provide insight into the effect of grafting density, poly (oxyalkylene amine) and acrylic acid chemistry on the physical and biological properties of the graft copolymers. Furthermore, we will continue to develop this novel antisense delivery system towards applications in cancer. Specifically, we will: (1) evaluate the effectiveness of our graft copolymers in several cell types with and without serum and (3) evaluate our delivery system in a tumor xenograft model.

Public Health Relevance

Materials for the safe and effective delivery of oligonucleotides currently prevent the widespread utilization of otherwise powerful gene silencing approaches to understanding gene function and treating human disease. By furthering development of novel vectors via both fundamental biophysical investigations of vector-cell interactions and disease model applications, this work will advance the development of gene silencing technologies.

Agency
National Institute of Health (NIH)
Institute
National Institute of Biomedical Imaging and Bioengineering (NIBIB)
Type
Research Project (R01)
Project #
5R01EB008278-07
Application #
7860545
Study Section
Gene and Drug Delivery Systems Study Section (GDD)
Program Officer
Zullo, Steven J
Project Start
2009-07-01
Project End
2012-06-30
Budget Start
2010-07-01
Budget End
2012-06-30
Support Year
7
Fiscal Year
2010
Total Cost
$344,934
Indirect Cost
Name
Rutgers University
Department
Biomedical Engineering
Type
Schools of Engineering
DUNS #
001912864
City
New Brunswick
State
NJ
Country
United States
Zip Code
08901
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Mishra, Swati; Peddada, Lavanya Y; Devore, David I et al. (2012) Poly(alkylene oxide) copolymers for nucleic acid delivery. Acc Chem Res 45:1057-66
Waite, Carolyn L; Roth, Charles M (2012) Nanoscale drug delivery systems for enhanced drug penetration into solid tumors: current progress and opportunities. Crit Rev Biomed Eng 40:21-41
Sparks, Sarah M; Waite, Carolyn L; Harmon, Alexander M et al. (2011) Efficient intracellular siRNA delivery by ethyleneimine-modified amphiphilic macromolecules. Macromol Biosci 11:1192-200
Waite, Carolyn L; Roth, Charles M (2011) Binding and transport of PAMAM-RGD in a tumor spheroid model: the effect of RGD targeting ligand density. Biotechnol Bioeng 108:2999-3008