Cancer is the second leading cause of death in the United States. Nearly half of all men and a little over one third of all women in the United States will develop cancer during their lifetimes. The a5?1 integrin and its ligand fibronectin have been implicated in suppressing tumor recurrence and metastasis in different tumor cells, including colon cancer (the third most common cancer in this country). In recent years there is a considerable effort to designing fibronectin-mimetic peptides that will target the integrin with increased therapeutic potentials. The PI has synthesized a novel peptide-amphiphile that contains both GRGDSP (the primary recognition site for a5?1), and PHSRN (the synergy site for a5?1) in a single peptide formulation that shows increased cell adhesion compared to other GRGDSP surfaces, and fibronectin. The objective of this proposal is to engineer a5?1-targeted stealth liposomes that will be stable, and will function as a platform for interactions with the a5?1 integrin. The central hypothesis of this application is that stealth liposomes functionalized with the novel peptide will show more efficient and specific binding to a5?1 integrin compared to stealth liposomes decorated with GRGDSP, or with no peptide. The efficacy of the design will be tested with in vitro studies with colon carcinoma cells that express high levels of the integrin. To test this hypothesis, and accomplish the objective of this proposal, the following two aims have been set.
Specific Aim 1 : Engineering of pH-sensitive a5?1-targeted stealth liposomes. These formulations will specifically bind to a5?1, get endocytoced, and release the load (toxic anticancer drugs, chemotherapy agents, or DNA) in an acidic pH environment. Studies will be carried out by flow cytometry, plate assays, and confocal microscopy using different fluorescent probes.
Specific Aim 2 : Engineering of phospholipase A2 (PLA2)-sensitive a5?1-targeted stealth liposomes. The objective here is to specifically target the integrin, and deliver the encapsulated load (a5?1 antagonists that inhibit tumor angiogenesis, tumor growth and metastasis) as a result of liposomal hydrolysis due to the PLA2 presence at the cancerous site. Different formulations will be evaluated via flow cytometry, and fluorescent studies with different fluorophores. Our novel peptide-amphiphile, will allow for the development of new pharmacological strategies for the prevention and treatment of a variety of other diseases where a5?1 is up-regulated. ? ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Biomedical Imaging and Bioengineering (NIBIB)
Type
Small Research Grants (R03)
Project #
5R03EB006125-02
Application #
7490450
Study Section
Gene and Drug Delivery Systems Study Section (GDD)
Program Officer
Henderson, Lori
Project Start
2007-09-01
Project End
2009-08-31
Budget Start
2008-09-01
Budget End
2009-08-31
Support Year
2
Fiscal Year
2008
Total Cost
$65,509
Indirect Cost
Name
University of Minnesota Twin Cities
Department
Engineering (All Types)
Type
Schools of Engineering
DUNS #
555917996
City
Minneapolis
State
MN
Country
United States
Zip Code
55455
Garg, Ashish; Kokkoli, Efrosini (2011) pH-Sensitive PEGylated liposomes functionalized with a fibronectin-mimetic peptide show enhanced intracellular delivery to colon cancer cell. Curr Pharm Biotechnol 12:1135-43
Atchison, Nicole A; Fan, Wei; Papas, Klearchos K et al. (2010) Binding of the fibronectin-mimetic peptide, PR_b, to alpha5beta1 on pig islet cells increases fibronectin production and facilitates internalization of PR_b functionalized liposomes. Langmuir 26:14081-8
Rexeisen, Emilie L; Fan, Wei; Pangburn, Todd O et al. (2010) Self-assembly of fibronectin mimetic peptide-amphiphile nanofibers. Langmuir 26:1953-9
Pangburn, Todd O; Petersen, Matthew A; Waybrant, Brett et al. (2009) Peptide- and aptamer-functionalized nanovectors for targeted delivery of therapeutics. J Biomech Eng 131:074005
Garg, Ashish; Tisdale, Alison W; Haidari, Eman et al. (2009) Targeting colon cancer cells using PEGylated liposomes modified with a fibronectin-mimetic peptide. Int J Pharm 366:201-10
Demirgoz, Done; Garg, Ashish; Kokkoli, Efrosini (2008) PR_b-targeted PEGylated liposomes for prostate cancer therapy. Langmuir 24:13518-24
Craig, Jennifer A; Rexeisen, Emilie L; Mardilovich, Anastasia et al. (2008) Effect of linker and spacer on the design of a fibronectin-mimetic peptide evaluated via cell studies and AFM adhesion forces. Langmuir 24:10282-92