Targeted delivery using tissue-specific peptidomimetic ligands

1. A tissue-specific targeting ligand for targeted delivery of therapeutic agents to a tissue comprising:

a composition of formula:

A-scaffold-A′,

wherein the scaffold is of the formula:

wherein the dotted lines represent the point of attachment to A and A′;

wherein A and A′ are monovalent peptidomimetric compounds, wherein each monovalent peptidomimetric compound is selected from the group consisting of the following fragments:

2. The targeted ligand of claim 1 , wherein A and A′ are the same.

3. The targeted ligand of claim 1 , wherein the tissue is a cancerous cell, tissue or endothelium selected from pancreatic cancer, breast cancer, non-small cell lung carcinoma (NSCLC), pancreatic cancer vascular endothelium or NSCLC cancer vascular endothelium.

4. A method for synthesizing a small molecule complex for targeted delivery of therapeutic agents, the method comprising the step of:

coupling covalently two unprotected monovalent peptidomimetric compounds, of formulas A and A′, to a scaffold,

wherein the scaffold is of the formula:

wherein the dotted lines represent the point of attachment to A and A′;

wherein A and A′ are monovalent peptidomimetric compounds, wherein each monovalent peptidomimetric compound is selected from the group consisting of the following fragments:

5. The method of claim 4 , wherein the selected monovalent peptidomimetic compounds are identical.

6. The method of claim 4 , wherein the tissue is a cancerous cell, tissue or endothelium selected from pancreatic cancer, breast cancer, non-small cell lung carcinoma (NSCLC), pancreatic cancer vascular endothelium or NSCLC cancer vascular endothelium.

7. A ligand-functionalized delivery system comprising:

a therapeutic agent carrier;

a tissue-specific targeting ligand for targeted delivery of therapeutic agents to a tissue comprising:

a composition of formula:

A-scaffold-A′,

wherein the scaffold is of the formula:

wherein the dotted lines represent the point of attachment to A and A′;

wherein A and A′ are monovalent peptidomimetric compounds, wherein each monovalent peptidomimetric compound is selected from the group consisting of the following fragments:

8. The ligand-functionalized delivery system of claim 7 , wherein the therapeutic agent carrier is a liposome.

9. The ligand-functionalized delivery system of claim 7 , wherein the therapeutic agent carrier is a cationic liposome having an internal lipid bilayer and an external lipid bilayer.

10. The ligand-functionalized delivery system of claim 7 , wherein the tissue is a cancerous cell, tissue or endothelium selected from pancreatic cancer, breast cancer, non-small cell lung carcinoma (NSCLC), pancreatic cancer vascular endothelium or NSCLC cancer vascular endothelium.

11. A method of delivering a payload to a target tissue comprising the steps of:

preparing a targeting ligand of a composition of formula:

A-scaffold-A′,

wherein the scaffold is of the formula:

wherein the dotted lines represent the point of attachment to A and A′;

wherein A and A′ are monovalent peptidomimetric compounds, wherein each monovalent peptidomimetric compound is selected from the group consisting of the following fragments:

incorporating the composition into a lipid bilayer, wherein the lipid bilayer is selected from the group consisting of a cell membrane, a subcellular membrane, a multilamellar vesicle, and a bilamellar vesicle,

wherein said lipid bilayer comprises a bilamellar liposome that encapsulates a therapeutic agent;

coating the liposome with a targeting ligand and producing a targeted liposome complex;

combining the resulting targeted liposome complex with a reversible masking reagent; and

administering a therapeutically effective amount of the masked targeted liposome complex to a patient in need thereof.

12. The method of claim 11 , wherein the liposome is a bilamellar invaginated vesicle.

13. The method of claim 11 , wherein the reversible masking agent is a small neutral lipid with a molecular weight of about 500 Da or lower.

14. The method of claim 13 , wherein the small neutral lipid is n-dodecyl-beta-D-maltopyranoside.

15. The method of claim 14 , wherein the target tissue is a human pancreatic cancer.

16. The method of claim 11 , wherein the targeting ligands are selected from the group consisting of compounds:

KB995, wherein the scaffold is of the formula:

wherein the dotted lines represent the point of attachment to A and A′;

wherein A and A′ are of the formula:

KB1005, wherein the scaffold is of the formula:

wherein the dotted lines represent the point of attachment to A and A′;

wherein A and A′ are of the formula:

KB1012, wherein the scaffold is of the formula:

wherein the dotted lines represent the point of attachment to A and A′;

wherein one of A and A′ is of the formula:

and the other one of A and A′ is of the formula:

and KB1109, wherein the scaffold is of the formula:

wherein the dotted lines represent the point of attachment to A and A′;

wherein one of A and A′ is of the formula:

and the other one of A and A′ is of the formula:

17. The method of claim 16 , wherein the target tissue is a human breast cancer.

18. The method of claim 11 , wherein the targeting ligands are selected from the group consisting of compounds:

KB1036, wherein the scaffold is of the formula:

wherein the dotted lines represent the point of attachment to A and A′;

wherein one of A and A′ is of the formula:

and the other one of A and A′ is of the formula:

KB1039, wherein the scaffold is of the formula:

wherein the dotted lines represent the point of attachment to A and A′;

wherein one of A and A′ is of the formula:

and the other one of A and A′ is of the formula:

KB1063, wherein the scaffold is of the formula:

wherein the dotted lines represent the point of attachment to A and A′;

wherein one of A and A′ is of the formula:

and the other one of A and A′ is of the formula:

KB1064, wherein the scaffold is of the formula:

wherein the dotted lines represent the point of attachment to A and A′;

wherein one of A and A′ is of the formula:

and the other one of A and A′ is of the formula:

KB1066, wherein the scaffold is of the formula:

wherein the dotted lines represent the point of attachment to A and A′;

wherein one of A and A′ is of the formula:

and the other one of A and A′ is of the formula:

KB1067, wherein the scaffold is of the formula:

wherein the dotted lines represent the point of attachment to A and A′;

wherein one of A and A′ is of the formula:

and the other one of A and A′ is of the formula:

19. The method of claim 18 , wherein the target tissue is a human non-small cell lung carcinoma.

20. The method of claim 11 , wherein the targeting ligands are selected from the group consisting of compounds:

KB1001, wherein the scaffold is of the formula:

wherein the dotted lines represent the point of attachment to A and A′;

wherein A and A′ are of the formula:

KB1003, wherein the scaffold is of the formula:

wherein the dotted lines represent the point of attachment to A and A′;

wherein A and A′ are of the formula:

KB1042, wherein the scaffold is of the formula:

wherein the dotted lines represent the point of attachment to A and A′;

wherein one of A and A′ is of the formula:

and the other one of A and A′ is of the formula:

KB1051, wherein the scaffold is of the formula:

wherein the dotted lines represent the point of attachment to A and A′;

wherein one of A and A′ is of the formula:

and the other one of A and A′ is of the formula:

KB1062, wherein the scaffold is of the formula:

wherein the dotted lines represent the point of attachment to A and A′;

wherein one of A and A′ is of the formula:

and the other one of A and A′ is of the formula:

KB1096, wherein the scaffold is of the formula:

wherein the dotted lines represent the point of attachment to A and A′;

wherein one of A and A′ is of the formula:

and the other one of A and A′ is of the formula:

KB1107, wherein the scaffold is of the formula:

wherein the dotted lines represent the point of attachment to A and A′;

wherein one of A and A′ is of the formula:

and the other one of A and A′ is of the formula:

KB1108, wherein the scaffold is of the formula:

wherein the dotted lines represent the point of attachment to A and A′;

wherein one of A and A′ is of the formula:

and the other one of A and A′ is of the formula:

KB1029, wherein the scaffold is of the formula:

wherein the dotted lines represent the point of attachment to A and A′;

wherein one of A and A′ is of the formula:

and the other one of A and A′ is of the formula:

21. The method of claim 20 , wherein the target tissue is a human non-small cell lung carcinoma vascular endothelium.

22. The method of claim 11 , wherein the targeting ligand is compound:

KB1061, wherein the scaffold is of the formula:

wherein the dotted lines represent the point of attachment to A and A′;

wherein one of A and A′ is of the formula:

and the other one of A and A′ is of the formula:

23. The method of claim 22 , wherein the target tissue is a human pancreatic cancer vascular endothelium.

24. The method of claim 22 , wherein the targeting ligand is compound:

KB1023, wherein the scaffold is of the formula:

wherein the dotted lines represent the point of attachment to A and A′;

wherein one of A and A′ is of the formula:

and the other one of A and A′ is of the formula:

25. The method of claim 24 , wherein the anticancer therapeutic agent is a plasmid DNA encoding the antiangiogenic protein human thrombospondin-1 (TSP1).

26. The method of claim 22 , wherein the target tissue is a melanoma.

27. The method of claim 11 , wherein the targeting ligands selected from the group consisting of compounds:

KB1037, wherein the scaffold is of the formula:

wherein the dotted lines represent the point of attachment to A and A′;

wherein one of A and A′ is of the formula:

and the other one of A and A′ is of the formula:

KB1109, wherein the scaffold is of the formula:

wherein the dotted lines represent the point of attachment to A and A′;

wherein one of A and A′ is of the formula:

and the other one of A and A′ is of the formula:

28. A method of isolating a peptidomimetric compound for binding to a target tissue comprising the steps of:

preparing a peptidomimetric library of compositions of formula:

A-scaffold-A′,

wherein the scaffold is of the formula:

wherein the dotted lines represent the point of attachment to A and A′;

wherein A and A′ are monovalent peptidomimetric compounds, wherein each monovalent peptidomimetric compound is selected from the group consisting of the following fragments:

contacting a target tissue with the peptidomimetric compounds;

isolating those peptidomimetric compounds that bind specifically to the target tissue; and

characterizing the formula of the composition that bound specifically to the target tissue.

29. The method of claim 28 , wherein the method is a high throughput assay and the target tissue includes cells from a patient that are assayed directly following a dissociation step.

30. The method of claim 28 , wherein binding of the peptidomimetic library is screened by comparing binding between tumor cells and normal cells.

31. The method of claim 28 , wherein the peptidomimetic library is screened directly using time resolved fluorometry.

32. The method of claim 28 , wherein the peptidomimetic library is screened in a transfection based system.

33. A method of screening for a peptidomimetric compound that binds to a target tissue or cell comprising the steps of:

preparing a peptidomimetric library of compositions of formula:

A-scaffold-A′,

wherein the scaffold is of the formula:

wherein the dotted lines represent the point of attachment to A and A′;

wherein A and A′ are monovalent peptidomimetric compounds, wherein each monovalent peptidomimetric compound is selected from the group consisting of the following fragments:

mixing the peptidomimetric compounds with lipids to form liposomes;

contacting a target tissue with the peptidomimetric compounds;

isolating those peptidomimetric compounds that bind specifically to the target tissues; and

characterizing the formula of the composition that bound specifically to the target tissue.

34. A method of screening for a peptidomimetric compound that binds to a target tissue or cell comprising the steps of:

preparing a peptidomimetric library of compositions of formula:

A-scaffold-A′,

wherein the scaffold is of the formula:

wherein the dotted lines represent the point of attachment to A and A′;

wherein A and A′ are monovalent peptidomimetric compounds, wherein each monovalent peptidomimetric compound is selected from the group consisting of the following fragments:

mixing the peptidomimetric compounds with lipids to form liposome, wherein the liposomes further comprise a nucleic acid for delivery to a cell;

contacting a target tissue with the peptidomimetric compounds;

isolating those peptidomimetric compounds that bind specifically to the target tissues; and

characterizing the formula of the composition that bound specifically to the target tissue.

35. The method of claim 34 , wherein the target tissue is defined further as cells in tissue culture.

36. The method of claim 34 , wherein the target tissue is defined further as cells in tissue culture and the cells are selected based on the effect of the nucleic acid on the cells.

37. The method of claim 34 , wherein the target tissue is defined further as cells in tissue culture, wherein the nucleic acid is a selective marker for negative or positive selection, expresses a selective marker for positive or negative selection, or expresses a detectable marker.