Methods and compositions for the treatment of cancer

1. A method for treating or ameliorating a disorder in a subject with a reduced dosage of a therapeutic agent, said method comprising:

reducing the level of a nucleic acid encoding GLI1 or the level of GLI1 protein in a cell of the subject, and

administering an effective amount of the therapeutic agent to the subject, wherein the effective amount of the therapeutic agent is less than the effective amount of the therapeutic agent in the absence of the reduction of the level of a nucleic acid encoding GLI1 or the level of GLI1 protein in a cell of the subject.

2. The method of claim 1 , wherein the level of a nucleic acid encoding GLI1 or the level of GLI1 protein is reduced by administering to the subject an isolated nucleic acid selected from a small hairpin RNA (shRNA), a small interfering RNA (siRNA), a micro RNA (miRNA), an antisense polynucleotide, and a ribozyme.

3. The method of claim 2 , wherein the isolated nucleic acid comprises a sequence encoding GLI1 or a fragment thereof, a sequence encoding antisense GLI1 or a fragment thereof, or an antisense nucleic acid complementary to a sequence encoding GLI1 or a fragment thereof.

4. The method of claim 3 , wherein the nucleic acid comprises a sequence selected from SEQ ID NO.s:01-10.

5. The method of claim 4 , wherein the nucleic acid comprises SEQ ID NO:01.

6. The method of claim 1 , wherein the therapeutic agent comprises a chemotherapeutic agent.

7. The method of claim 6 , wherein the chemotherapeutic agent is selected from a platinum-based compound such as cisplatin, carboplatin, nedaplatin, oxaliplatin, satraplatin, and triplatin tetranitrate, a nitrogen mustard such as cyclophosphamide, mechlorethamine, uramustine, melphalan, chlorambucil, and ifosfamide, a nitrosoureas such as carmustine, lomustine, and streptozocin, an alkyl sulfonate such as busulfan, thiotepa, procarbazine, and altretamine.

8. The method of claim 7 , wherein the chemotherapeutic agent comprises a platinum-based compound.

9. The method of claim 8 , wherein the platinum-based compound comprises cisplatin.

10. The method of claim 6 , wherein the chemotherapeutic agent is selected from the group consisting of taxol and doxirubicin.

11. The method of claim 3 , wherein increased expression of ERRC1, XPD, or XRCC1 results in increased cellular resistance to the therapeutic agent.

12. The method of claim 3 , wherein increased activity of a nucleotide excision repair pathway results in increased cellular resistance to the therapeutic agent.

13. The method of claim 3 , wherein increased activity of a base excision repair pathway results in increased cellular resistance to the therapeutic agent.

14. The method of claim 12 , wherein the cellular resistance further comprises clinical resistance to the therapeutic agent.

15. The method of claim 3 , wherein the disorder comprises cancer.

16. The method of claim 15 , wherein the cancer is selected from breast cancer, melanoma, prostate cancer, colorectal cancer, head and neck cancer, lung cancer, colon cancer, oesophageal cancer, gastric cancer, testicular cancer, and ovarian cancer.

17. The method of claim 1 , wherein the subject is a mammal.

18. The method of claim 17 , wherein the mammal is a human.

19. The method of claim 1 , wherein the nucleic acid encoding GLI1 comprises a nucleic acid encoding GLI1-130, or the GLI1 protein comprises GLI1-130 isoform.

20. A method for reducing the dosage of a therapeutic agent needed to treat a disorder in a subject comprising administering to the subject a nucleic acid comprising a sequence selected from SEQ ID NO.s:01-10, wherein the administration reduces the level of a nucleic acid encoding GLI1 or the level of GLI1 protein in a cell of the subject.

21. The method of claim 1 , wherein said disorder is ovarian cancer and said therapeutic agent is a platinum-based chemotherapeutic compound.

22. The method of claim 21 , wherein said platinum-based chemotherapeutic compound comprises cisplatin.