Chimeric toxins for targeted therapy

Abstract

The present invention relates particularly to neoplastic cells targeted chimeric toxins comprising of cell targeting moieties and cell killing moieties for recognizing and for destroying the neoplastic cells, wherein the cell targeting moieties consist of gonadotropin releasing hormone homologues and the cell killing moieties consist of Pseudomonas Exotoxin A. The present invention further relates to pharmaceutical compositions containing as an active ingredient these neoplastic cells targeted chimeric toxins and to a method for the production of these chimeric toxins. The said invention also relates to a method for cancer therapy, treating malignant carcinoma cells and benign hyperplasia including uterine leiomyoma cells, extrauterine endometrial island cells, benign hyperplasia of prostate and breast and pituitary tumor adenoma cells, by the use of the above-mentioned chimeric toxins.

1 . A fused chimeric protein comprising a linear genetically engineered peptide encoded by an oligonucleotide that includes
 A) DNA encoding at least one cell targeting moiety consisting essentially of Met-GnRH or a Met-GnRH analog that specifically binds to GnRH binding sites on Caco2 adenocarcinoma cells; and   B) DNA encoding at least one cell killing moiety;   
       wherein the peptide includes Met-GnRH or a Met-GnRH analog, and at least one cell killing moiety. 
     
     
         2 . A fused chimeric protein according to  claim 1 , wherein the DNA encoding at least one cell killing moiety encodes a mutated full length  Pseudomonas  exotoxin (PE). 
     
     
         3 . A fused chimeric protein according to  claim 1 , wherein the DNA encoding at least one cell killing moiety encodes a DNA fragment comprising domains II and III of the  Pseudomonas  exotoxin (PE). 
     
     
         4 . A method for the production of a fused chimeric protein as defined in  claim 2 , comprising preparing the oligonucleotide by ligating the DNA encoding Met-GnRH or a Met-GnRH analog upstream of the DNA fragment encoding the mutated form of PE, and expressing the oligonucleotide under conditions sufficient to produce the fused chimeric protein. 
     
     
         5 . A method for the production of a fused chimeric protein as defined in  claim 3 , comprising preparing the oligonucleotide by ligating the DNA encoding Met-GnRH or a Met-GnRH analog upstream to the DNA fragment encoding domains II and III of PE, and expressing the oligonucleotide under conditions sufficient to produce the fused chimeric protein. 
     
     
         6 . A composition useful for treatment in cancer therapy comprising the fused chimeric protein as defined in  claim 1 . 
     
     
         7 . A plasmid comprising a promoter operably linked to a DNA molecule encoding a fused chimeric protein as defined in  claim 1 . 
     
     
         8 . A chimeric protein comprising a genetically engineered molecule comprising a fusion of
 at least one cell targeting moiety consisting essentially of gonadotropin releasing hormone (GnRH) preceded by a Met (Met-GnRH) or a Met-GnRH analog that specifically binds to GnRH binding sites on Caco2 adenocarcinoma; and at least one cell killing moiety.   
     
     
         9 . A chimeric protein as claimed in  claim 8 , wherein said cell killing moiety comprises  Pseudomonas  exotoxin A. 
     
     
         10 . A chimeric protein as claimed in  claim 8 , that has no amino acid between said cell killing moiety and said cell targeting moiety. 
     
     
         11 . A chimeric protein as claimed in  claim 8 , wherein said chimeric protein recognizes and/or binds to GnRH-binding sites on adenocarcinoma and hepatocarcinoma cells. 
     
     
         12 . The chimeric protein of  claim 8 , wherein said cell targeting moiety is Met-GnRH. 
     
     
         13 . The chimeric protein of  claim 8 , wherein said cell targeting moiety is a Met-GnRH analog. 
     
     
         14 . The chimeric protein of  claim 8 , wherein said cell targeting moiety is a Met-GnRH analog that includes Trp in a position corresponding to GnRH position 6. 
     
     
         15 . A chimeric protein comprising i) a Met proceeding GnRH or a GnRH analog and ii) a peptide selected from the group consisting of a) a mutated full length  Pseudomonas  exotoxin, and b) domains II and III of the  Pseudomonas  exotoxin. 
     
     
         16 . The chimeric protein of claim  21  wherein the chimeric protein includes Met-GnRH-PE66. 
     
     
         17 . The chimeric protein of claim  21  wherein the chimeric protein includes Met-GnRH-PE40.