Peptides whose uptake by cells is controllable
View Patent ↗A generic structure for the peptides of the present invention includes A-X-B-C, where C is a cargo moiety, the B portion includes basic amino acids, X is a cleavable linker sequence, and the A portion includes acidic amino acids. The intact structure is not significantly taken up by cells; however, upon extracellular cleavage of X, the B-C portion is taken up, delivering the cargo to targeted cells. Cargo may be, for example, a contrast agent for diagnostic imaging, a chemotherapeutic drug, or a radiation-sensitizer for therapy. Cleavage of X allows separation of A from B, unmasking the normal ability of the basic amino acids in B to drag cargo C into cells near the cleavage event. X is cleaved extracellularly, preferably under physiological conditions. D-amino acids are preferred for the A and B portions, to minimize immunogenicity and nonspecific cleavage by background peptidases or proteases.
1. A method for transporting a fluorescent moiety across a membrane of a cell, comprising:
contacting the cell with a molecule comprising Formula (I):
wherein
C is a fluorescent cargo moiety,
B is a peptide with a sequence comprising a series of 5 to 20 basic amino acids,
A is a peptide with a sequence comprising 5 to 9 consecutive acidic amino acids, wherein the amino acids are selected from aspartates and glutamates,
X is a cleavable linker which is cleavable by a matrix metalloprotease, and
Q is a fluorescence-quenching moiety that quenches the fluorescence of C
whereby the cargo moiety is transported across the membrane of the cell following cleavage of the cleavable linker X.
2. The method of claim 1 , wherein A is a peptide sequence comprising 8 consecutive glutamates.
3. The method of claim 1 , wherein B is a peptide sequence comprising 9 to 16 consecutive arginines.
4. The method of claim 1 , wherein B is a peptide sequence comprising 9 consecutive arginines.
5. The method of claim 1 , wherein B is a peptide sequence comprising 8 consecutive arginines.
6. The method of claim 1 , wherein (a) A is a peptide sequence comprising 8 to 9 consecutive glutamates arid (b) B is a peptide sequence comprising 9 consecutive arginines.
7. The method of claim 1 , wherein X is cleaved in the extracellular space.
8. A method of labeling a cell, comprising:
contacting the cell with a molecule of Formula (I):
wherein
C is a fluorescent cargo moiety,
B is a peptide with a sequence comprising a series of 5 to 20 basic amino acids,
A is a peptide with a sequence comprising 5 to 9 consecutive acidic amino acids, wherein the amino acids are selected from aspartates and glutamates,
X is a cleavable linker which is cleavable by a matrix metalloprotease, and
Q is a fluorescence-quenching moiety that quenches the fluorescence of C
whereby the marker cargo moiety is transported across the membrane of the cell following cleavage of the cleavable linker X.
9. The method of claim 8 , wherein (a) A is a peptide sequence comprising 8 to 9 consecutive glutamates and (b) B is a peptide sequence comprising 9 consecutive arginines.
10. A method of labeling a cell in an individual in need thereof, comprising:
administering to an individual a molecule of Formula (I):
wherein
C is a fluorescent marker cargo moiety,
B is a peptide with a sequence comprising a series of 5 to 20 basic amino acids,
A is a peptide with a sequence comprising 5 to 9 consecutive acidic amino acids, wherein the amino acids are selected from aspartates and glutamates, and
X is a cleavable linker which is cleavable by a matrix metalloprotease, and
Q is a fluorescence-quenching moiety that quenches the fluorescence of C
whereby the marker cargo moiety is transported across the membrane of the cell following cleavage of the cleavable linker X.
11. The method of claim 10 , wherein (a) A is a peptide sequence comprising 8 to 9 consecutive glutamates and (b) B is a peptide sequence comprising 9 consecutive arginines.