Compositions and methods for inhibiting expression of XBP-1 gene

1. A method of inhibiting XBP-1 expression in a cell, the method comprising:

(a) introducing into the cell a double stranded RNA (dsRNA), wherein said dsRNA comprises a sense strand and an antisense strand that together form a region of complementarity less than 30 base pairs in length, and wherein said sense strand and said antisense strand are each less than 30 nucleotides in length, and wherein said antisense strand is complementary to at least 15 contiguous nucleotides of CACCCUGAAUUCAUUGUCU (SEQ ID NO: 2149); and

(b) maintaining the cell produced in step (a) for a time sufficient to obtain degradation of the mRNA transcript of an XBP-1 gene, thereby inhibiting expression of the XBP-1 gene in the cell.

2. The method of claim 1 , wherein said antisense strand or said sense strand comprises at least one modified nucleotide.

3. The method of claim 2 , wherein at least one of said modified nucleotides is chosen from the group of: a 2′-O-methyl modified nucleotide, a nucleotide comprising a 5′-phosphorothioate group, and a terminal nucleotide linked to a cholesteryl derivative, vitamin E, or dodecanoic acid bisdecylamide group.

4. The method of claim 2 , wherein said modified nucleotide is chosen from the group of: a 2′-deoxy-2′-fluoro modified nucleotide, a 2′-deoxy-modified nucleotide, a locked nucleotide, an abasic nucleotide, 2′-amino-modified nucleotide, 2′-alkyl-modified nucleotide, morpholino nucleotide, a phosphoramidate, and a non-natural base comprising nucleotide.

5. The method of claim 1 , wherein said antisense strand comprises SEQ ID NO: 2150.

6. The method of claim 1 , wherein said sense strand comprises SEQ ID NO: 2149.

7. The method of claim 1 , wherein said antisense strand consists of SEQ ID NO: 2150.

8. The method of claim 1 , wherein said sense strand consists of SEQ ID NO: 2149.

9. The method of claim 1 , wherein said antisense strand comprises SEQ ID NO: 2178 (AGAcAAUGAAUUcAGGGUGdTsdT).

10. The method of claim 1 , wherein said sense strand comprises SEQ ID NO: 2177 (cAcccuGAAuucAuuGucudTsdT).

11. The method of claim 1 , wherein said antisense strand consists of SEQ ID NO: 2178.

12. The method of claim 1 , wherein said sense strand consists of SEQ ID NO: 2177.

13. The method of claim 1 , wherein said antisense strand consists of SEQ ID NO: 2178 and said sense strand consists of SEQ ID NO: 2177.

14. The method of claim 1 , wherein introducing said dsRNA into said cell inhibits expression of the XBP-1 gene by at least 40% compared to a level of XBP-1 gene expression prior to contact of said cell with said dsRNA.

15. The method of claim 1 , wherein said cell is a cancer cell.

16. A method of decreasing XBP-1 expression in a liver of an animal and decreasing plasma cholesterol levels in said animal, comprising administering a double stranded RNA (dsRNA) to said animal, wherein said dsRNA comprises a sense strand and an antisense strand that together form a region of complementarity less than 30 base pairs in length, and wherein said sense strand and said antisense strand are each less than 30 nucleotides in length, and wherein said antisense strand is complementary to at least 15 contiguous nucleotides of CACCCUGAAUUCAUUGUCU (SEQ ID NO: 2149).

17. The method of claim 16 , wherein said antisense strand comprises SEQ ID NO: 2150.

18. The method of claim 16 , wherein said sense strand comprises SEQ ID NO: 2149.

19. The method of claim 16 , wherein said human has cancer, a metabolic disease, a cardiovascular disease, or a neurological disease.

20. The method of claim 16 , wherein administering comprises administration by injection.

21. The method of claim 20 , wherein said injection is intravenous, intraarterial, subcutaneous, intraperitoneal or intramuscular injection.

22. The method of claim 16 , wherein said animal is a mouse.

23. The method of claim 16 , wherein said animal is a human.