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.
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).
| Anchordoquy, Thomas J; Simberg, Dmitri (2017) Watching the gorilla and questioning delivery dogma. J Control Release 262:87-90 |
| Betker, Jamie L; Anchordoquy, Thomas J (2017) Assessing the effect of a nude mouse model on nanoparticle-mediated gene delivery. Drug Deliv Transl Res 7:162-167 |
| Betker, Jamie L; Anchordoquy, Thomas J (2017) Nonadditive Effects of Repetitive Administration of Lipoplexes in Immunocompetent Mice. J Pharm Sci 106:872-881 |
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| Betker, Jamie L; Anchordoquy, Thomas J (2015) Effect of charge ratio on lipoplex-mediated gene delivery and liver toxicity. Ther Deliv 6:1243-53 |
| Smyth, Tyson; Kullberg, Max; Malik, Noeen et al. (2015) Biodistribution and delivery efficiency of unmodified tumor-derived exosomes. J Control Release 199:145-55 |
| Betker, Jamie L; Anchordoquy, Thomas J (2015) Relating toxicity to transfection: using sphingosine to maintain prolonged expression in vitro. Mol Pharm 12:264-73 |
| Smyth, Tyson J; Redzic, Jasmina S; Graner, Michael W et al. (2014) Examination of the specificity of tumor cell derived exosomes with tumor cells in vitro. Biochim Biophys Acta 1838:2954-65 |
| Payton, Nicole M; Wempe, Michael F; Xu, Yemin et al. (2014) Long-term storage of lyophilized liposomal formulations. J Pharm Sci 103:3869-3878 |
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