Construction of cell penetrating nucleic acids

Abstract

This invention provides pH-responsive zwitterionic nucleotides and nucleic acids comprising said nucleotides, wherein said zwitterions are constituted from one or more anionic internucleoside linkages and one or more cationic moieties and said zwitterionic nucleotides further comprise either one or more hydrophobic moieties or one or more TEE's with the general structure (I) Hydrophobic element-pH-responsive hydrophilic elements (I).

1 . A pH-responsive zwitterionic nucleotide, comprising one or more anionic internucleoside linkages, preferably selected from the group consisting of phosphate diesters, phosphothioates and phosphodithioates, one or more cationic moieties, comprising a nitrogen base, and either one or more hydrophobic moieties or one or more transfection enhancer elements {TEE's) having the general formula
   Hydrophobic element-pH-responsive hydrophilic elements  (I),
   
       wherein said hydrophobic moieties or said hydrophobic element of the one or more TEE's are linear, branched or cyclic chains with 40 units, wherein said chains preferably consist of carbon atoms, preferably in form of hydrocarbon or methylene groups, and wherein said pH-responsive hydrophilic element is selected from weak acids having a pKa of between 2 and 6, or zwitterionic structures comprising a combination of weak or strong acidic groups with weak bases, having a pKa of between 3 and 8. 
     
     
         2 . The pH-responsive zwitterionic nucleotide of  claim 1 , comprising a nucleoside and wherein said cationic moieties are substituted to the 2′, 4′ or 1′ position of the nucleoside. 
     
     
         3 . The pH-responsive zwitterionic nucleotide of  claim 2 , wherein said nucleoside comprises a ribose, furanose, pyranose or hexitol ring structure. 
     
     
         4 . The pH-responsive zwitterionic nucleotide of  claim 2 , wherein said nucleoside comprises a hemiacetal or acetal structure. 
     
     
         5 . The pH-responsive zwitterionic nucleotide of  claim 1 , wherein log D of the nucleotides at pH4 is greater than−1. 
     
     
         6 . The pH-responsive zwitterionic nucleotide of  claim 5 , wherein characterized in that their log D of the nucleotides at pH4 is smaller than +3. 
     
     
         7 . The pH-responsive zwitterionic nucleotide of  claim 1 , wherein said nucleotide comprises a cationic moiety having a pK equal or greater than 7.5 and one or more TEE's, having a hydrophilic element which is a carboxylic acid. 
     
     
         8 . The pH-responsive zwitterionic nucleotide of  claim 1 , wherein said nucleotide comprises a cationic moiety having a pK equal or lower than 7.5 and one or more hydrophobic moieties. 
     
     
         9 . The pH-responsive zwitterionic nucleotide of  claim 1 , wherein said nucleotide comprises a cationic moiety have a pK equal or lower than 7.5 and one or more TEE's having a hydrophilic element which is a carboxylic acid. 
     
     
         10 . The pH-responsive zwitterionic nucleotide of  claim 7 , wherein said nucleotide is selected from the structures in table 12, and comprising hydrophobic moieties with the size specified therein. 
     
     
         11 . The pH-responsive zwitterionic nucleotide of  claim 10 , wherein said nucleotide is selected from the structures IPN 1-10 through to IPN 1-17. 
     
     
         12 . The pH-responsive zwitterionic nucleotide of  claim 8 , wherein said nucleotide is selected from the structures in table 8, wherein the one or more hydrophobic moieties have the size specified therein. 
     
     
         13 . The pH-responsive zwitterionic nucleotide of  claim 12 , wherein said nucleotide is selected from the structures IPN2-1 through to IPN2-24. 
     
     
         14 . The pH-responsive zwitterionic nucleotide of  claim 9 , wherein said nucleotide is selected from the structures in table 16, and comprising hydrophobic moieties with the size specified therein. 
     
     
         15 . The pH-responsive zwitterionic nucleotide of  claim 14 , wherein said nucleotide is selected from the structures IPN3-10 through to IPN3-27. 
     
     
         16 . The pH-responsive zwitterionic nucleotide of  claim 1 , wherein said nucleotide further comprises hemiacetal or acetal groups at their 2′ position, and comprising hydrophobic moieties with an adjusted size as specified in table 20. 
     
     
         17 . A nucleic acid comprising the pH-responsive zwitterionic nucleotides according to  claim 1 . 
     
     
         18 . The nucleic acid according to  claim 17 , wherein no more than ⅔ of all nucleotides are of IPN type. 
     
     
         19 . The nucleic acid according to  claim 18 , wherein about 50% of all nucleotides are of IPN type. 
     
     
         20 . The nucleic acid according to  claim 18 , wherein the hydrophobic moiety of the IPN nucleotides comprises between 4 and 12 carbon atoms. 
     
     
         21 . The nucleic acid according to  claim 17 , wherein the nucleotides are selected from the species in tables 10, 15 or 19.