Compounds and methods for enzyme-mediated tumor imaging and therapy

1. A compound represented by the formula:

in which

R 1 is H, COOH, amino, mono- or di(C 1 -C 6 alkyl)amino, halogen, C 1 -C 8 alkyl, C 2 -C 8 alkenyl, C 2 -C 8 alkynyl, C 3 -C 8 cycloalkyl, aryl, C 1 -C 8 alkoxy, nitro, or cyano; or R 1 is a radionuclide or a moiety containing, or capable of complexing with, a radionuclide;

R 2 is, independently for each occurrence, H, hydroxy, COOH, amino, mono- or di(C 1 -C 6 alkyl)amino, C 1 -C 8 alkyl, C 2 -C 8 alkenyl, C 2 -C 8 alkynyl, C 3 -C 8 cycloalkyl, aryl, halogen, C 1 -C 8 alkoxy, nitro, cyano, or a radionuclide or a moiety containing, or capable of complexing with, a radionuclide;

R 3 , R 4 , R 6 and R 7 are each independently a direct bond or a group which can be cleaved by an enzyme;

R 5 and R 8 are each independently a group which can be cleaved by an enzyme selected from the group consisting of prostate specific antigen, matrix metalloproteinases, guanidinobenzoatase, prostate specific membrane antigen, alkaline phosphatase, prostatic acid phosphatase, and human sulfatase-1; and

Y is, independently for each occurrence, O, S or NH;

provided that at least one occurrence of R 1 or R 2 is a radionuclide or a moiety containing, or capable of complexing with, a radionuclide;

or a pharmaceutically acceptable salt thereof.

2. The compound of claim 1 , wherein the moiety capable of complexing with a radionuclide includes metal-chelating moieties such as diamino-dithiolate ligands, amino-amido-dithiolate ligands, and ligands such as diethylenetriaminepentaacetic acid (DTPA), diaminedithiol (DADT) ligands, 1,4,7,10-tetraazacyclotetradecane-1,4,7,10-tetraacetic acid (DOTA) and derivatives thereof.

3. The compound of claim 1 , wherein the compound is

or a pharmaceutically acceptable salt thereof.