In the recent years, we have successfully modified the Liposome/Protamine/DNA (LPD) nanoparticle formulation for targeted delivery of siRNA to the human lung cancer cells in a xenograft model. This core/shell, self-assembled nanoparticles contained a compact protamine/DNA/siRNA core which is wrapped around by two cationic lipid bilayers. When the nanoparticles were incubated with a polyethylene glycol (PEG)-phospholipid conjugate (DSPE-PEG), the outer bilayer was stripped off, but the inner bilayer survived with a high degree of PEGylation. The densely packed surface PEG formed a brush protection layer to shield the cationic charges of the nanoparticles and reduced opsonization by serum proteins. The result was a very low degree of uptake by the liver and the spleen, and a very high level of tumor uptake, up to 60-80% injected dose per g tissue. If a targeting ligand, anisamide, was tethered to the distal end of PEG, the targeted nanoparticles efficiently delivered siRNA to silence a target gene in the entire tumor. However, upon a closer look at the delivered siRNA, most of the dose was sequestered in the endosomes and was not bioavailable. This is because the formulation did not possess any endosomal lytic activity. Thus, we propose to replace the core of LPD with Ca phosphate (CaP) which dissolves at the acidic endosome pH. We expect that dissolved CaP will significantly increase the osmotic pressure of the endosome and induce swelling and rupture of the organelle, resulting in the release of the encapsulated siRNA. The proposed improvement of the non-viral vector will combine high level of tumor uptake and efficient endosome release of the siRNA cargo. The other aim of the project will deal with tumors with not-so-leaky neovasculature. We have successfully prepared small bioactive lipoplex (SBL) by mixing siRNA and a cationic lipid, DOTAP, in a fluorohydrocarbon solvent at an elevated temperature and pressure. The resulting nanoparticles were small (30-50 nm), and active in transfection. We will further modify the surface of SBL with PEGylation and ligand tethering. We expect that the new nanoparticle will deliver siRNA to tumor cells in which the neovasculature is not so leaky.

Public Health Relevance

The project will address two pressing issues in delivering siRNA to the tumor. The first is to improve the release of siRNA from the endosome to the cytoplasm. The other is to transport siRNA to tumors with not-so-leaky vasculature. If successful, the project will significantly advance siRNA as cancer therapeutics.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA149363-04
Application #
8433254
Study Section
Gene and Drug Delivery Systems Study Section (GDD)
Program Officer
Fu, Yali
Project Start
2010-04-01
Project End
2015-01-31
Budget Start
2013-02-01
Budget End
2014-01-31
Support Year
4
Fiscal Year
2013
Total Cost
$276,372
Indirect Cost
$87,173
Name
University of North Carolina Chapel Hill
Department
Pharmacology
Type
Schools of Pharmacy
DUNS #
608195277
City
Chapel Hill
State
NC
Country
United States
Zip Code
27599
Guo, Shutao; Huang, Leaf (2014) Nanoparticles containing insoluble drug for cancer therapy. Biotechnol Adv 32:778-88
Liu, Yang; Hu, Yunxia; Huang, Leaf (2014) Influence of polyethylene glycol density and surface lipid on pharmacokinetics and biodistribution of lipid-calcium-phosphate nanoparticles. Biomaterials 35:3027-34
Miao, Lei; Guo, Shutao; Zhang, Jing et al. (2014) Nanoparticles with Precise Ratiometric Co-Loading and Co-Delivery of Gemcitabine Monophosphate and Cisplatin for Treatment of Bladder Cancer. Adv Funct Mater 24:6601-6611
Zhang, Jing; Miao, Lei; Guo, Shutao et al. (2014) Synergistic anti-tumor effects of combined gemcitabine and cisplatin nanoparticles in a stroma-rich bladder carcinoma model. J Control Release 182:90-6
Guo, Shutao; Miao, Lei; Wang, Yuhua et al. (2014) Unmodified drug used as a material to construct nanoparticles: delivery of cisplatin for enhanced anti-cancer therapy. J Control Release 174:137-42
Guo, Shutao; Lin, C Michael; Xu, Zhenghong et al. (2014) Co-delivery of cisplatin and rapamycin for enhanced anticancer therapy through synergistic effects and microenvironment modulation. ACS Nano 8:4996-5009
Guo, Shutao; Wang, Yuhua; Miao, Lei et al. (2014) Turning a water and oil insoluble cisplatin derivative into a nanoparticle formulation for cancer therapy. Biomaterials 35:7647-53
Xu, Zhenghong; Wang, Yuhua; Zhang, Lu et al. (2014) Nanoparticle-delivered transforming growth factor-? siRNA enhances vaccination against advanced melanoma by modifying tumor microenvironment. ACS Nano 8:3636-45
Zhang, Jing; Li, Xiang; Huang, Leaf (2014) Non-viral nanocarriers for siRNA delivery in breast cancer. J Control Release 190:440-50
Haynes, Matthew; Huang, Leaf (2014) Hepatic RNA Interference: Delivery by Synthetic Vectors. Drug Deliv Transl Res 4:61-73

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