Polyconjugates for Delivery of RNAi triggers to Tumor Cells In Vivo

Abstract

The present invention is directed compositions for delivery of RNA interference (RNAi) triggers to integrin positive tumor cells in vivo. The compositions comprise RGD ligand-targeted amphipathic membrane active polyamines reversibly modified with enzyme cleavable dipeptide-amidobenzyl-carbonate masking agents. Modification masks membrane activity of the polymer while reversibility provides physiological responsiveness. The reversibly modified polyamines (dynamic polyconjugate or conjugate) are further covalently linked to an RNAi trigger.

We claim: 
     
         1 . A compound for delivering an RNAi trigger to an integrin positive tumor cell in vivo comprising the structure represented by:
   R-L-P-RNAi trigger   wherein, R comprises an RGD mimic, L comprises a physiologically labile linkage, and P comprises a membrane active polyamine.   
     
     
         2 . The compound of  claim 1  wherein the integrin is an α v β 3  integrin. 
     
     
         3 . The compound of  claim 2  wherein the RGD mimic comprises a guanidinium group linked to a glycine-aspartate dipeptide via an amide bond. 
     
     
         4 . The compound of  claim 3  wherein L comprises:
   A 1 A 2 -amidobenzyl-carbamate 
 wherein, A 1  is a hydrophobic amino acid and A 2  is a hydrophilic uncharged amino acid linked to A 1  via an amide bond, wherein said hydrophilic uncharged amino acid is uncharged at neutral pH. 
 
     
     
         5 . The compound of  claim 4  wherein A 1  is selected from the group consisting of: alanine, phenylalanine, valine, leucine, isoleucine, and tryptophan. 
     
     
         6 . The compound of  claim 5  wherein A 2  is selected from the group consisting of: citrulline, threonine, asparagine, and glutamine. 
     
     
         7 . The compound of  claim 6  wherein the R-A 1 A 2 -amidobenzyl-carbamate-P has the structure represented by: 
       
         
           
           
               
               
           
         
         wherein R 4  comprises the RGD mimic, R 1  is the side group of a hydrophobic amino acid, R 2  is the side group of a hydrophilic uncharged amino acid and polyamine is the membrane active polyamine P. 
       
     
     
         8 . The compound of  claim 3  wherein the RGD mimic comprises the structure represented by: 
       
         
           
           
               
               
           
         
       
     
     
         9 . The compound of  claim 8  wherein the guanidinium is selected from 
       
         
           
           
               
               
           
         
         and its resonance structures, or 
       
       
         
           
           
               
               
           
         
         H and its resonance structures. 
       
     
     
         10 . The compound of  claim 1  wherein the membrane active polyamine is reversibly modified. 
     
     
         11 . The compound of  claim 1  further comprising a polyethylene glycol linked to the membrane active polyamine via a reversible physiologically labile covalent linkage. 
     
     
         12 . The compound of  claim 11  wherein the compound has the structure represented by: 
       
         
           
           
               
               
           
         
         wherein N is the RNAi trigger, L 1  is optional and if present is a physiologically labile linkage, PEG comprises polyethylene glycol, y is an integer greater than zero, z is an integer greater than zero. 
       
     
     
         13 . An RGD mimic containing compound comprising the structure represented by:
   R-A 1 A 2 -amidobenzyl-carbonate   wherein, R comprises an RGD mimic, A 1  is a hydrophobic amino acid, A 2  is a hydrophilic uncharged amino acid linked to A 1  via an amide bond and carbonate comprises an amine reactive carbonate moiety capable of reacting with the amine to form a carbamate.   
     
     
         14 . The compound of  claim 13  wherein A 1  is selected from the group consisting of: alanine, phenylalanine, valine, leucine, isoleucine, and tryptophan. 
     
     
         15 . The compound of  claim 13  wherein A 2  is selected from the group consisting of: citrulline, threonine, asparagine, and glutamine. 
     
     
         16 . The compound of  claim 15  wherein the R-A 1 A 2 -amidobenzyl-carbonate has the structure represented by: 
       
         
           
           
               
               
           
         
         wherein R 1  is the side group hydrophobic amino acid A 1 , R 2  is the side group of a hydrophilic uncharged amino acid A 2 , and R 3  is —CH 2 —O—C(O)—Z wherein —Z is 
       
       
         
           
           
               
               
           
         
       
     
     
         17 . The compound of  claim 13  wherein the RGD mimic comprises the structure represented by: 
       
         
           
           
               
               
           
         
         wherein the guanidinium is selected from 
       
       
         
           
           
               
               
           
         
         
           and its resonance structures, or 
         
       
       
         
           
           
               
               
           
         
         
           and its resonance structures. 
         
       
     
     
         18 . The compound of  claim 13  wherein the RNA mimic comprise a PEG linking moiety. 
     
     
         19 . The compound of  claim 16  wherein
 a) R 1  is selected from the group consisting of —CH 3 , —(CH 2 )-phenyl, —CH—(CH 3 ) 2 , —CH 2 —CH—(CH 3 ) 2 , —CH(CH 3 )—CH 2 —CH 3 , tryptophan, and 
 b) R 2  is selected from the group consisting of —(CH 2 ) 3 —NH—C(O)—NH 2 , —CH 2 —C(O)—NH 2 , and —(CH 2 ) 2 —C(O)—NH 2 .