Method of down-regulating gene expression

Abstract

Disclosed is a method of down-regulating the expression of a gene in an animal, wherein a pharmacological formulation comprising a chimeric oligonucleotide complementary to the gene is orally administered to an animal. The oligonucleotide administered has at least one phosphorothioate internucleotide linkage and at least one alkylphosphonate, phosphorodithioate, alkylphosphonothioate, phosphoramidate, phosphoramidite, phosphate ester, carbamate, carbonate, phosphate triester, acetamidate, or carboxymethyl ester internucleotide linkage.

What is claimed is:  
     
         1 . A method for introducing an intact oligonucleotide into a mammal, comprising the step of orally administering an oligonucleotide of about 15 to about 25 nucleotides, the oligonucleotide comprising at least one phosphorothioate internucleotide linkage, and further comprising at least one 2′-O-alkoxyalkyl ribonucleotide, 
 wherein the oligonucleotide is present in intact form in the systemic plasma and liver tissue of the mammal at least six hours following oral administration.  
 
     
     
         2 . The method of  claim 1 , wherein the 2′-O-alkoxyalkyl ribonucleotide is at the 3′ terminus of the oligonucleotide.  
     
     
         3 . The method of  claim 2 , wherein the oligonucleotide comprises at least two 2′-O-alkoxyalkyl ribonucleotides at the 3′ terminus of the oligonucleotide.  
     
     
         4 . The method of  claim 2 , wherein the oligonucleotide further comprises at least one 2′-substituted ribonucleotide at the 5′ terminus.  
     
     
         5 . The method of  claim 1 , wherein the oligonucleotide further comprises a phosphorothioate internucleotide linkage between every nucleotide.  
     
     
         6 . The method of  claim 1 , wherein the 2′-O-alkoxyalkyl ribonucleotide is a 2′-O-methoxyethyl ribonucleotide.  
     
     
         7 . A method for introducing an intact oligonucleotide into a mammal, comprising the step of orally administering an oligonucleotide of about 15 to about 25 nucleotides, the oligonucleotide comprising at least one non-phosphodiester internucleotide linkage, and further comprising at least one 2′-O-alkoxyalkyl ribonucleotide at the 5′ terminus and at least one 2′-O-alkoxyalkyl ribonucleotide at the 3′ terminus, 
 wherein the oligonucleotide is present in intact form in the systemic plasma and liver tissue of the mammal at least six hours following oral administration.  
 
     
     
         8 . The method of  claim 7 , wherein the 2′-O-alkoxyalkyl ribonucleotide is a 2′-O— methoxyethyl-ribonucleotide.  
     
     
         9 . The method of  claim 7 , wherein oligonucleotide is a hybrid antisense oligonucleotide.  
     
     
         10 . The method of  claim 9 , wherein the oligonucleotide comprises at least one deoxyribonucleotide.  
     
     
         11 . The method of  claim 9 , wherein the oligonucleotide further comprises at least three contiguous deoxyribonucleotides.  
     
     
         12 . The method of  claim 9 , wherein the oligonucleotide comprises a region of at least four contiguous deoxyribonucleotides that activate RNase H activity.  
     
     
         13 . The method of  claim 7 , wherein the oligonucleotide is complementary to a single-stranded target nucleic acid.  
     
     
         14 . The method of  claim 7 , wherein oligonucleotide is complementary to a gene.  
     
     
         15 . The method of  claim 7 , wherein the oligonucleotide is complementary to a partial sequence of a gene or of a gene transcript.  
     
     
         16 . The method of  claim 7 , wherein all of the ribonucleotides in the oligonucleotide are 2′-substituted ribonucleotides.  
     
     
         17 . The method of  claim 7 , wherein the oligonucleotide comprises an internucleotide linkage selected from the group consisting of alkylphosphonates, phosphorothioates, phosphorodithioates, alkylphosphonothioates, phosphoramidates, phosphoramidites, phosphate esters, carbamates, carbonates, phosphate triesters, acetamidate, and carboxymethyl esters.  
     
     
         18 . The method of  claim 17 , wherein essentially all of the nucleotides are linked via phosphorothioate or phosphorodithioate internucleotide linkages.  
     
     
         19 . The method of  claim 7 , wherein the oligonucleotide is modified.  
     
     
         20 . The method of  claim 7 , wherein the oligonucleotide is complementary to a partial sequence of a gene or a gene transcript of a virus, a pathogenic organism, or a cellular gene.  
     
     
         21 . The method of  claim 7 , wherein the oligonucleotide is complementary to a partial sequence of a gene or a gene transcript of a virus involved in a disease selected from the group consisting of AIDS, oral and genital herpes, papilloma warts, influenza, foot and mouth disease, yellow fever, chicken pox, shingles, adult T-cell leukemia, Burkitt's lymphoma, nasopharyngeal carcinoma, and hepatitis.  
     
     
         22 . The method of  claim 7 , wherein the oligonucleotide is complementary to a partial sequence of a gene or a gene transcript encoding a protein associated with Alzheimer's disease.  
     
     
         23 . The method of  claim 7 , wherein the oligonucleotide is complementary to a partial sequence of a gene or a gene transcript encoding a protein in a parasite causing a parasitic disease selected from the group consisting of amebiasis, Chagas' disease, toxoplasmosis, pneumocytosis, giardiasis, cryptoporidiosis, trichomoniasis, malaria, ascariasis, filariasis, trichinosis and schistosomiasis infections.  
     
     
         24 . The method of  claim 7 , wherein the oligonucleotide is complementary to a partial sequence of an HIV gene or a gene transcript and comprises about 15 to 26 nucleotides linked by phosphorothioate internucleoside linkages.