The work described in this proposal represents a truly new strategy for improving the targeting of lipid-based delivery vehicles to specific sites in vivo. Previous studies on intravenous delivery have demonstrated the need to have prolonged circulation times in order for vehicles to accumulate in target tissues (e.g., tumors). The predominant strategy for achieving prolonged circulation times is via PEGylation, but studies have shown that this strategy can compromise delivery, suggesting that it would be advantageous to develop alternative strategies. Our previous work has demonstrated the ability of lipid nanoparticles containing high cholesterol contents to avoid aggregation in blood and accumulate in tumors. In addition, our most recent work has demonstrated that cholesterol can form nanodomains at very high concentrations, mimicking lipid "rafts" that endow biological membranes with multiple functionalities. The proposed studies exploit this lipid mixing behavior to create regions of the delivery vehicle that can be used as anchoring sites for targeting ligands. A significant advantage of this approach is that cholesterol nanodomains appear to remain free of protein, suggesting that ligands located within nanodomains will not be compromised by protein fouling upon intravenous administration. Our preliminary results are consistent with this hypothesis, and demonstrate that ligands located within the nanodomain dramatically improve transfection rates in cell culture and in vivo, in contrast to the identical ligand when it is excluded from the nanodomain. The experiments outlined in this proposal investigate the effects of lipid composition on nanodomain formation in order to fully exploit lipid mixing behavior to improve targeting. The proposed studies will also optimize ligand density, spacer length, uptake and delivery in cell culture, before testing this strategy in a xenograft mouse model. Furthermore, the experiments will assess the ability of two small molecule ligands (KYT-0353, anisamide) to deliver three different drug cargoes (plasmid, siRNA, and doxorubicin) both in vitro and in vivo. Accordingly, the proposed studies will thoroughly investigate the use of nanodomains to improve vehicle targeting, and assess the applicability of this approach to different drug types.

Public Health Relevance

There is a need to target drugs directly to specific sites (e.g., tumors) by developing delivery systems that are able to bind to these tissues in vivo, i.e., a magic bullet. Previous attempts at utilizing molecules that bind specifically to certain cells have met with limited success, although some critical lessons have been learned. The proposed work takes advantage of the physical properties of lipids to create a delivery system with enhanced binding capacity. This entirely new strategy for targeting drugs to specific sites should be applicable to a wide variety of drugs (e.g., genes, RNA, anti-cancer agents).

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM093287-03
Application #
8532683
Study Section
Gene and Drug Delivery Systems Study Section (GDD)
Program Officer
Okita, Richard T
Project Start
2011-09-15
Project End
2015-08-31
Budget Start
2013-09-01
Budget End
2014-08-31
Support Year
3
Fiscal Year
2013
Total Cost
$278,076
Indirect Cost
$94,726
Name
University of Colorado Denver
Department
Pharmacology
Type
Schools of Pharmacy
DUNS #
041096314
City
Aurora
State
CO
Country
United States
Zip Code
80045
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Payton, Nicole M; Wempe, Michael F; Xu, Yemin et al. (2014) Long-term storage of lyophilized liposomal formulations. J Pharm Sci 103:3869-78
Kullberg, Max; McCarthy, Ryan; Anchordoquy, Thomas J (2014) Gene delivery to Her-2+ breast cancer cells using a two-component delivery system to achieve specificity. Nanomedicine 10:1253-62
Betker, Jamie L; Gomez, Joe; Anchordoquy, Thomas J (2013) The effects of lipoplex formulation variables on the protein corona and comparisons with in vitro transfection efficiency. J Control Release 171:261-8
Kullberg, Max; McCarthy, Ryan; Anchordoquy, Thomas J (2013) Systemic tumor-specific gene delivery. J Control Release 172:730-6
Payton, N M; Wempe, M F; Betker, J L et al. (2013) Lyophilization of a triply unsaturated phospholipid: effects of trace metal contaminants. Eur J Pharm Biopharm 85:306-13
Betker, Jamie L; Kullberg, Max; Gomez, Joe et al. (2013) Cholesterol domains enhance transfection. Ther Deliv 4:453-62
Xu, Long; Betker, Jamie; Yin, Hao et al. (2012) Ligands located within a cholesterol domain enhance gene delivery to the target tissue. J Control Release 160:57-63