Carboxylated 2′-amino-LNA nucleotides and oligonucleotides comprising the same

1. An oligonucleotide comprising from 3 to 100 nucleotide units, wherein at least one nucleotide unit independently copmrises a carboxylated 2′-amino locked nucleic acid (LNA) nucleotides of formula (1′)

wherein:

B is a nucleobase,

each of L 1 is independently an internucleoside linkage, a bond to a neighboring nucleotide unit or a terminal moiety selected from the group consisting of —OH, phosphate, and a linker for the conjugation of the oligonucleotide to another molecule, and

R is a carboxylated substituent comprising one or two carboxyl group(s) and wherein R comprises from 6 to 40 carbon atoms and from 0 to 3 heteroatoms selected from the group consisting of O, N, and S.

2. The oligonucleotide according to claim 1 , wherein said oligonucleotide comprises from 5 to 50 nucleotides and is double stranded.

3. The oligonucleotide according to claim 1 , wherein R has from 6 to 20 carbon atoms.

4. The oligonucleotide according to claim 1 , wherein said carboxylated substituent is a carboxyhydrocarbyl group or a carboxyheterohydrocarbyl group, the carboxyheterohydrocarbyl group comprises from 1 to 3 heteroatoms selected from the group consisting of O, N, and S.

5. The oligonucleotide according to claim 1 , wherein said carboxylated substituent is a carboxyalkyl substituent or a carboxyaryl substituent.

6. The oligonucleotide according to claim 1 , wherein the internucleoside linkage is selected from phosphodiester, phosphorothioate, or phosphotriester linkage.

7. The oligonucleotide according to claim 1 , wherein less than 40% of the total number of nucleotide units in the oligonucleotide are carboxylated 2′-amino LNA nucleotide units of the general formulas (1′).

8. The oligonucleotide according to claim 1 , wherein said oligonucleotide contains at most 8 of said carboxylated 2′-amino LNA nucleotide units of formula (1′).

9. The oligonucleotide according to claim 1 , wherein said oligonucleotide has, from the 5′-end to the 3′-end, three segments: a 5′-end segment of at least 2 nucleotide units, a central binding segment of at least 6 nucleotide units in length, and a 3′-end segment of at least 2 nucleotide units in length, and

wherein said oligonucleotide contains at least one carboxylated 2′-amino-LNA nucleotide in each of said end segments, but none in the central segment.

10. The oligonucleotide according to claim 1 , wherein at least one nucleotide unit is a hydrophobic nucleotide unit independently selected from the group consisting of:

2′ amino LNA nucleotide moieties carrying on said 2′-amino group a (hetero)hydrocarbyl substituent comprising from 8 to 40 carbon atoms and from 0 to 3 heteroatoms selected from the group consisting of O, N, and S;

2′-N—C 3 -C 7 -alkyl-amino-LNA nucleotide moieties;

2′-N—C 3 -C 7 -alkyl-amido-LNA nucleotide moieties;

2′-O—C 3 -C 26 -alkyl-RNA nucleotide moieties;

2′-O—C 6 -C 26 -aryl-RNA nucleotide moieties,

2′-O—C 1 -C 6 -alkyloxy-C 3 -C 26 -alkyl-RNA nucleotide moieties; and

2′-O—C 1 -C 6 -alkyloxy-C 6 -C 26 -aryl-RNA nucleotide moieties.

11. The oligonucleotide according to claim 10 , wherein less than 30% of the total number of nucleotide units in the oligonucleotide are hydrophobic nucleotide units.

12. The oligonucleotide according to claim 1 , wherein the carboxylated 2′-amino LNA nucleotide unit of formula (1′) is a nucleotide unit of formula (1″) or (1′″):

13. A method for transfecting cells, comprising mixing an oligonucleotide of claim 1 with an aqueous buffer and treating said cells with the mixture.

14. A pharmaceutical composition comprising an oligonucleotide of claim 1 and a pharmaceutically acceptable diluent, carrier or adjuvant.

15. The oligonucleotide according to claim 1 , wherein said oligonucleotide comprises from 10 to 30 nucleotides and is single stranded.

16. An oligonucleotide, comprising from 3 to 100 nucleotide units, wherein at least one nucleotide unit independently comprises a 2′-amino locked nucleic acid (LNA) nucleotide of structure (11) to (16), wherein Y is oxygen, or Y is absent when the carbon attached to Y is a methylene group:

(11)

wherein x is 1, 2, 3, 4, 5, 7, 9, 11 or 13 ;

(12)

wherein the hydrocarbyl moiety is an oleoyl residue ;

(13)

wherein x is 2, 3, 4, 5, 6, 7, 8, 10, 12 or 14 ;

(14)

wherein x is 1, 2, 3, 4, 5, 6, 7, 8, 9, 11 or 13 and Z is H or a methyl, ethyl, propyl, butyl, pentyl or hexyl group or a constitutional isomer thereof and the combined number of carbon atoms in x and Z is from 1 to 13 ;

(15)

wherein x is 1, 2, 3, 4, 5,6, 7, 8, 9, 11 or 13 and Z is H or a methyl, ethyl, propyl, butyl, pentyl or hexyl group or a constitutional isomer thereof and the combined number of carbon atoms in x and Z is from 1 to 13 ; and

(16)

wherein x is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or 12 and Z is H or a methyl, ethyl, propyl, butyl, pentyl or hexyl group or a constitutional isomer thereof and the combined number of carbon atoms in x and Z is from 1 to 13.

17. The oligonucleotide of claim 1 , wherein less than 40% of the total number of nucleotide units in the oligonucleotide are carboxylated 2′ amino LNA nucleotides.

18. The oligonucleotide of claim 1 , wherein the combined portion of carboxylated 2′ amino LNA nucleotides does not exceed 40% of all nucleotides of the oligonucleotide.

19. The oligonucleotide of claim 1 , comprising a sequence that is identical or complementary to a sequence found in a genome.

20. The oligonucleotide of claim 1 , wherein the carboxyalated 2′ amino nucleotides are located close to the 5′ and 3′ ends of the oligonucleotide, from positions 1 to 5 from the 5′ end of the oligonucleotide and/or positions t to (t−4) from its 3′-terminal end, wherein t designates the number of the 3′-terminal nucleotide counted from the 5′-terminal nucleotide unit of the oligonucleotide.