Lin28-mediated control of let-7 biogenesis
The present embodiments provide for compositions and methods that regulate microRNA-binding protein-mediated miRNA biogensis; for example Lin28-mediated biogenesis of let-7; and in particular Lin28A-recruited 3′ terminal uridylyl transferase (TUTase) uridylation of pre-let-7. A particular embodiment provide compositions and methods for screening for agents that inhibit TUTase-dependent Lin28A-mediated repression of let-7 miRNA.
1. A method of inhibiting Lin28A-mediated let-7 repression in a cell comprising contacting said cell with an inhibitor of TUTaseU, wherein the cell expresses Lin28A and is in a tissue in a subject, and wherein the amount of let-7 in the tissue is increased in the presence of the inhibitor relative to in the absence of the inhibitor.
2. A method of inhibiting tumor growth or preventing tumor or cancer metastasis in a subject in need thereof comprising administering a therapeutically effective amount of an inhibitor of a TUTase and a pharmaceutically acceptable carrier, whereby tumor growth is inhibited in the presence of the inhibitor, wherein the tumor or cancer in the subject expresses Lin28A.
3. The method of claim 2 , further comprising measuring the level of expression of Lin28A in a in a sample of cancerous tissue obtained from the subject prior to administering the TUTase inhibitor.
4. The method of claim 2 , wherein the TUTase is Zcchc11 or Zcchc6.
5. The method of claim 2 , wherein the inhibitor inhibits the expression of Zcchc11 or Zcchc6.
6. The method of claim 2 , wherein the inhibitor inhibits the activity of Zcchc11 or Zcchc6.
7. The method of claim 2 , wherein the inhibitor is selected from the group consisting of an antibody, a RNA interference molecule, a small molecule, a peptide and an aptamer.
8. The method of claim 7 , wherein the inhibitor is a RNA interference molecule.
9. The method of claim 8 , wherein the RNA interference molecule is a short-hairpin RNA.
10. The method of claim 9 , wherein the RNA interference molecule is a short-hairpin RNA directed specifically against the Zcchc11 gene or the Zcchc6 gene.
11. The method of claim 2 , wherein the cancer is colon, breast, ovarian, or prostate cancer.
12. The method of claim 2 , wherein administering the inhibitor of the TUTase increases the expression level of let-7a level in the subject by at least 2-fold.
13. The method of claim 2 , wherein administering the inhibitor of the TUTase increases the expression level of let-7a level in the subject by about 2- to about 10-fold.