Modulation of line-1 reverse transcriptase

1. A method of treating an individual suffering from a cancer, said method comprising:

determining that a sample comprising cancer cells from the individual are telomerase negative and show alternative lengthening of telomeres mediated by a reverse transcriptase encoded by L-1 (LINE-1) retrotransposon, and

administering to the individual in need thereof a therapeutically effective amount of a composition comprising an inhibitor or antagonist of the reverse transcriptase,

wherein the inhibitor or antagonist blocks said lengthening of telomeres,

wherein said cells show telomere shortening, G2 arrest and apoptosis, and

wherein the inhibitor or antagonist is a nucleoside analog that is at least one selected from the group consisting of: 3′-azido-2′,3′-dideoxythymidine (AZT), 2′,3′-dideoxyinosine (ddI) and 2′,3′-didehydro-3′-deoxythymidine (d4T).

2. The method of claim 1 , wherein the nucleoside analog is ddI.

3. The method of claim 1 , wherein the nucleoside analog is d4T.

4. The method of claim 1 , wherein the nucleoside analog is 3′-azido-2′,3′-dideoxythymidine (AZT).

5. The method of claim 1 , wherein the cancer is osteosarcoma, breast carcinoma, ovarian carcinoma, lung carcinoma, adrenocortical carcinoma or melanoma.

6. The method of claim 1 , wherein the composition is administered orally, parenterally, subcutaneously, intramuscularly, intravascularly or topically.

7. A method for treating a cancer in a human, the method comprising:

determining that a sample comprising cancer cells from the individual are telomerase negative and show alternative lengthening of telomeres and L-1 (LINE-1) retrotransposon encoded reverse transcriptase activity, and

administering to the human in need thereof a therapeutically effective amount of a composition comprising one or more nucleoside analogs, or a pharmaceutically acceptable salt thereof,

wherein said nucleoside analogs block said lengthening of telomeres,

wherein said cells show telomere shortening, G2 arrest and apoptosis, and

wherein said nucleoside analogs are 3′-azido-2′,3′-dideoxythymidine (AZT), 2′,3′-dideoxyinosine (ddI) and 2′,3′-didehydro-3′-deoxythymidine (d4T).

8. The method of claim 7 , wherein said nucleoside analogs are selected from the group consisting of: 3′-azido-2′,3′-dideoxythymidine (AZT) and 2′,3′-dideoxyinosine (MI).

9. The method of claim 7 , wherein the cancer is osteosarcoma, breast carcinoma, ovarian carcinoma, lung carcinoma, adrenocortical carcinoma or melanoma.

10. The method of claim 7 , wherein the composition is administered orally, parenterally, subcutaneously, intramuscularly or intravascularly.

11. The method of claim 7 , wherein a composition comprising two or more said nucleoside analogs are administered.

12. The method of claim 7 , wherein the amount of one of said nucleoside analogs administered is from about 100 mg/kg of body weight to about 500 mg/kg of body weight per day.

13. A method of interfering with lengthening of telomeres in telomerase negative tumor cells in need thereof, the method comprising administering to the cells an effective amount of an inhibitor or antagonist of reverse transcriptase encoded by L-1 (LINE-1) retrotransposon in the cells wherein the inhibitor or antagonist blocks said lengthening of telomeres in said cells, and wherein the inhibitor or antagonist is a nucleoside analog, which is 3′-azido-2′,3′-dideoxythymidine (AZT), 2′,3′-dideoxyinosine (ddI) or 2′,3′-didehydro-3′-deoxythymidine (d4T).

14. The method of claim 13 , wherein the nucleoside analog is ddI.

15. The method of claim 13 , wherein the nucleoside analog is d4T.

16. The method of claim 13 , wherein the nucleoside analog is 3′-azido-2′,3′-dideoxythymidine (AZT).

17. The method of claim 13 , wherein said tumor cells are osteosarcoma, breast carcinoma, ovarian carcinoma, lung carcinoma, adrenocortical carcinoma or melanoma.

18. A method of inhibiting the growth of a telomerase negative cell in need thereof showing alternative lengthening of telomeres, the method comprising:

contacting the cell with a nucleoside analog, wherein the nucleoside analog blocks said lengthening of telomeres,

wherein the nucleoside analog is 3′-azido-2′,3′-dideoxythymidine (AZT), 2′,3′-dideoxyinosine (ddI) or 2′,3′-didehydro-3′-deoxythymidine (d4T).

19. The method of claim 18 , wherein the cell is contacted with AZT.

20. The method of claim 19 , wherein the cell is contacted with 0.2 μM AZT.

21. The method of claim 18 , wherein the cell is contacted with ddI.

22. The method of claim 18 , wherein the cell is contacted with d4T.

23. The method of claim 18 , wherein the telomerase negative cell is a cancer cell, wherein the cancer cell is selected from the group consisting of osteosarcoma, breast carcinoma, ovarian carcinoma, lung carcinoma, adrenocortical carcinoma or melanoma.

24. A method for interfering with Line-1 reverse transcriptase(L1RT) activity in a human cancer cell in vitro comprising providing to the human cancer cell showing alternative lengthening of telomeres induced or mediated by L1RT activity, an amount of a nucleoside analog, wherein the nucleoside analog blocks said lengthening of telomeres, and wherein the nucleoside analog is 3′-azido-2′,3′-dideoxythymidine (AZT), 2′,3′-dideoxyinosine (ddI) or 2′,3′-didehydro-3′-deoxythymidine (d4T) administered in an amount effective to interfere with L 1 RT activity in the human cancer cell.

25. The method of claim 24 , wherein the nucleoside analog is 3′-azido-2′,3′-dideoxythymidine (AZT).

26. The method of claim 24 , wherein the nucleoside analog is 2′,3′-dideoxyinosine (ddI).

27. The method of claim 24 , wherein the nucleoside analog is 2′,3′-didehydro-3′-deoxythymidine (d4T).