Fluorescent photoprobe for the imaging of endothelin receptors

Abstract

The present invention relates to an endothelin receptor antagonist conjugate of the formula (I) wherein R 2 is an alkoxy group and one of R 1 and R 3 represents an alkoxy group and the other represents a group of the formula: (OCH 2 CH 2 ) n —NH—X, wherein n is an integer of 1 to 100 and X represents a fluorescent dye and tautomers thereof. Furthermore, the present invention relates to a diagnostic composition comprising the compounds of the invention. The present invention also relates to the use of the compounds of the invention for the preparation of a diagnostic composition for the diagnosis of cancer, the evaluation of cancer biology and/or monitoring of anticancer therapy. In a further aspect, the present invention relates to kits comprising the compounds of the invention.

1 . A method of fluorescence mediated tomography or fluorescence reflectance imaging comprising steps of:
 administering to a mammalian subject a diagnostic composition comprising an endothelin receptor antagonist conjugate of formula (I)   
       
         
           
           
               
               
           
         
       
       wherein R 2  is an alkoxy group and one of R 1  and R 3  represents an alkoxy group and the other represents a group of the formula: (OCH 2 CH 2 ) n —NH—X, wherein n is an integer ranging from 1 to 100 and X is a fluorescent dye or a tautomer thereof; and
 performing fluorescence mediated tomography or fluorescence reflectance imaging to detect the conjugate. 
 
     
     
         2 . The method of  claim 1  where, in the conjugate of formula (I), R 1  and R 2  are —OCH 3 . 
     
     
         3 . The method of  claim 1  where, in the conjugate of formula (I), the fluorescent dye possesses an absorption maximum from about 600 nm to 850 nm. 
     
     
         4 . The method of  claim 1  where, in the conjugate of formula (I), n is 4. 
     
     
         5 . The method of  claim 1  where, in the conjugate of formula (I), the fluorescent dye is selected from Cy 5, Cy 5.5, Cy 7, C3, Cy 3.5, fluorescein (FITC), heptamethylene thiocyanine, ROX, TAMRA, CAL Red, Red 640, FAM, TET, HEX, Oregon Green, TRITC, APC, DY-751, ATTO 740, ATTO 725 and ATTO 700. 
     
     
         6 . The method of  claim 1  where the conjugate of formula (I) is selected from 
       
         
           
           
               
               
           
         
       
       and tautomers thereof. 
     
     
         7 . The method of  claim 1  where the diagnostic composition further comprises a diagnostic carrier. 
     
     
         8 . A method for in vivo imaging of ET A -receptor density in a mammalian subject, the method comprising steps of:
 administering to a mammalian subject an endothelin receptor antagonist conjugate of formula (I)   
       
         
           
           
               
               
           
         
       
       wherein R 2  is an alkoxy group and one of R 1  and R 3  represents an alkoxy group and the other represents a group of the formula: (OCH 2 CH 2 ) n —NH—X, wherein n is an integer ranging from 1 to 100 and X is a fluorescent dye or a tautomer thereof; and
 performing in vivo imaging to detect the conjugate and determine ET A -receptor density. 
 
     
     
         9 . The method of  claim 8  where, in the conjugate of formula (I), R 1  and R 2  are —OCH 3 . 
     
     
         10 . The method of  claim 8  where, in the conjugate of formula (I), the fluorescent dye possesses an absorption maximum from about 600 nm to 850 nm. 
     
     
         11 . The method of  claim 8  where, in the conjugate of formula (I), n is 4. 
     
     
         12 . The method of  claim 8  where, in the conjugate of formula (I), the fluorescent dye is selected from Cy 5, Cy 5.5, Cy 7, C3, Cy 3.5, fluorescein (FITC), heptamethylene thiocyanine, ROX, TAMRA, CAL Red, Red 640, FAM, TET, HEX, Oregon Green, TRITC, APC, DY-751, ATTO 740, ATTO 725 and ATTO 700. 
     
     
         13 . The method of  claim 8  where the conjugate of formula (I) is selected from 
       
         
           
           
               
               
           
         
       
       and tautomers thereof. 
     
     
         14 . A method of (i) diagnosing cancer, (ii) evaluating cancer biology or (iii) monitoring the progress of anti-cancer therapy comprising a step of
 administering to a mammalian subject (i) suspected of having cancer, (ii) having cancer or (iii) undergoing anti-cancer therapy, respectively, an endothelin receptor antagonist conjugate of formula (I)   
       
         
           
           
               
               
           
         
       
       wherein R 2  is an alkoxy group and one of R 1  and R 3  represents an alkoxy group and the other represents a group of the formula: (OCH 2 CH 2 )—NH—X, wherein n is an integer ranging from 1 to 100 and X is a fluorescent dye or a tautomer thereof, and
 detecting the conjugate to (i) diagnose cancer, (ii) evaluate cancer biology or (iii) monitor the progress of anti-cancer therapy. 
 
     
     
         15 . The method of  claim 14  where, in the conjugate of formula (I), R 1  and R 2  are —OCH 3 . 
     
     
         16 . The method of  claim 14  where, in the conjugate of formula (I), the fluorescent dye possesses an absorption maximum from about 600 nm to 850 nm. 
     
     
         17 . The method of  claim 14  where, in the conjugate of formula (I), n is 4. 
     
     
         18 . The method of  claim 14  where, in the conjugate of formula (I), the fluorescent dye is selected from Cy 5, Cy 5.5, Cy 7, C3, Cy 3.5, fluorescein (FITC), heptamethylene thiocyanine, ROX, TAMRA, CAL Red, Red 640, FAM, TET, HEX, Oregon Green, TRITC, APC, DY-751, ATTO 740, ATTO 725 and ATTO 700. 
     
     
         19 . The method of  claim 14  where the conjugate of formula (I) is selected from 
       
         
           
           
               
               
           
         
       
       and tautomers thereof. 
     
     
         20 . The method of  claim 14 , wherein the cancer is selected from breast cancer, ovarian cancer, cervix carcinoma, bone malignancies, renal cancer, lung cancer, melanoma, prostate cancer, colon cancer, Karposi's sarcoma and CNS tumors.