Protease-activated contrast agents for in vivo imaging

Abstract

Compounds useful as contrast agents in image-guided surgery are provided. The compounds comprise a latent cationic lysosomotropic fragment that is detectable upon cleavage by lysosomal proteases within treated tissues, particularly within tumors and other diseased tissues. Also provided are compositions comprising the compounds and methods for using the compounds, for example in dynamically monitoring protease activity in vivo during image-guided tumor resection surgery.

1 - 20 . (canceled) 
     
     
         21 . A compound having the formula (III): 
       
         
           
           
               
               
           
         
       
       wherein
 D is a detectable element, wherein D comprises a cyanine label or a near infrared fluorescent label; 
 L 0  is a linker, wherein L 0  is an optionally substituted alkyl linker, wherein each carbon atom is optionally replaced with a heteroatom; and 
 T is a protease targeting element, wherein T is a peptidic targeting element containing no more than four amino acid residues and wherein T comprises a QSY quencher or QC-1; 
 
       provided that L 0  does not comprise an ethoxyethoxy spacer. 
     
     
         22 - 24 . (canceled) 
     
     
         25 . The compound of  claim 21 , wherein the cyanine label is Cy5. 
     
     
         26 . (canceled) 
     
     
         27 . The compound of  claim 21 , wherein the near infrared fluorescent label is a benzopyrillium or cyanine label. 
     
     
         28 . The compound of  claim 27 , wherein the benzopyrillium or cyanine label is a DyLight label. 
     
     
         29 - 30 . (canceled) 
     
     
         31 . The compound of  claim 21 , wherein L 0  is a C 2-8  alkyl linker. 
     
     
         32 . (canceled) 
     
     
         33 . The compound of  claim 21 , wherein the QSY quencher is a hydrophilic QSY quencher. 
     
     
         34 . The compound of  claim 33 , wherein the hydrophilic QSY quencher is a sulfo-QSY quencher. 
     
     
         35 - 37 . (canceled) 
     
     
         38 . The compound of  claim 21 , wherein T is a cathepsin targeting element. 
     
     
         39 . The compound of  claim 38 , wherein T is selective for cathepsin L or cathepsin V. 
     
     
         40 . The compound of  claim 21 , wherein T is 
       
         
           
           
               
               
           
         
         AA 1  and AA 2  is each independently an amino acid side chain; 
         U is O, N, or S; 
         R is alkyl, alkenyl, alkynyl, aryl, aralkyl, heteroaryl, heteroaralkyl, cycloalkyl, cycloalkenyl, cycloalkylalkyl, heterocyclyl, heterocyclylalkyl, or a protecting group, and is optionally substituted with 1 to 3 A groups; and 
         each A is independently alkyl, alkenyl, alkynyl, alkoxy, alkanoyl, alkylamino, aryl, aryloxy, arylamino, aralkyl, aralkoxy, aralkanoyl, aralkamino, heteroaryl, heteroaryloxy, heteroarylamino, heteroaralkyl, heteroaralkoxy, heteroaralkanoyl, heteroaralkamino, cycloalkyl, cycloalkenyl, cycloalkylalkyl, cycloalkoxy, cycloalkanoyl, cycloalkamino, heterocyclyl, heterocyclyloxy, heterocyclylamino, heterocyclylalkyl, heterocyclylalkoxy, heterocyclylalkanoyl, heterocyclylalkamino, hydroxyl, thio, amino, alkanoylamino, aroylamino, aralkanoylamino, alkylcarboxy, carbonate, carbamate, guanidinyl, urea, halo, trihalomethyl, cyano, nitro, phosphoryl, sulfonyl, sulfonamido, or azido. 
       
     
     
         41 . The compound of  claim 40 , wherein AA 1  is a basic amino acid side chain and AA 2  is an aralkyl amino acid side chain, each optionally substituted with 1 to 3 A groups. 
     
     
         42 . The compound of  claim 40 , wherein U is O. 
     
     
         43 - 51 . (canceled) 
     
     
         52 . The compound of  claim 40 , wherein
 AA 1  is -L 1 -Q;   wherein L 1  is a linker; and   Q is the quencher.   
     
     
         53 . The compound of  claim 52 , wherein L 1  is an optionally substituted alkyl linker, wherein each carbon atom is optionally replaced with a heteroatom. 
     
     
         54 . The compound of  claim 53 , wherein L 1  is a C 2-8  alkyl linker. 
     
     
         55 . The compound of  claim 54 , wherein L 1  is a C 4  alkyl linker. 
     
     
         56 . The compound of  claim 52 , wherein AA 2  is an aralkyl amino acid side chain, optionally substituted with 1 to 3 A groups. 
     
     
         57 . The compound of  claim 52 , wherein U is O. 
     
     
         58 . The compound of  claim 52 , wherein Q is a QSY quencher. 
     
     
         59 . The compound of  claim 58 , wherein the QSY quencher is a hydrophilic QSY quencher. 
     
     
         60 . The compound of  claim 59 , wherein the hydrophilic QSY quencher is a sulfo-QSY quencher. 
     
     
         61 . A composition for use in labeling a tissue in an animal comprising a compound of claim  1  and a pharmaceutically acceptable carrier. 
     
     
         62 - 67 . (canceled)