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Regulation of p27Kip1 by miRNA 221/222 in glioblastoma.
- Source :
-
Cell cycle (Georgetown, Tex.) [Cell Cycle] 2007 Aug 15; Vol. 6 (16), pp. 2005-9. Date of Electronic Publication: 2007 May 31. - Publication Year :
- 2007
-
Abstract
- Levels of p27(Kip1), a key negative regulator of the cell cycle, are often decreased in cancer. In most cancers, levels of p27(Kip1) mRNA are unchanged and increased proteolysis of the p27(Kip1) protein is thought to be the primary mechanism for its downregulation. Here we show that p27(Kip1) protein levels are also downregulated by microRNAs in cancer cells. We used RNA interference to reduce Dicer levels in human glioblastoma cell lines and found that this caused an increase in p27(Kip1) levels and a decrease in cell proliferation. When the coding sequence for the 3'UTR of the p27(Kip1) mRNA was inserted downstream of a luciferase reporter gene, Dicer depletion also enhanced expression of the reporter gene product. The microRNA target site software TargetScan predicts that the 3'UTR of p27(Kip1) mRNA contains multiple sites for microRNAs. These include two sites for microRNA 221 and 222, which have been shown to be upregulated in glioblastoma relative to adjacent normal brain tissue. The genes for microRNA 221 and microRNA 222 occupy adjacent sites on the X chromosome; their expression appears to be coregulated and they also appear to have the same target specificity. Antagonism of either microRNA 221 or 222 in glioblastoma cells also caused an increase in p27(Kip1) levels and enhanced expression of the luciferase reporter gene fused to the p27(Kip1) 3'UTR. These data show that p27(Kip1) is a direct target for microRNAs 221 and 222, and suggest a role for these microRNAs in promoting the aggressive growth of human glioblastoma.
- Subjects :
- Blotting, Western
Cell Cycle genetics
Cell Line, Tumor
Cyclin-Dependent Kinase Inhibitor p27 genetics
Flow Cytometry
Gene Expression Regulation, Neoplastic
Glioblastoma genetics
Glioblastoma metabolism
Glioblastoma pathology
Humans
RNA Interference
Reverse Transcriptase Polymerase Chain Reaction
Transfection
Cell Cycle physiology
Cyclin-Dependent Kinase Inhibitor p27 metabolism
MicroRNAs genetics
Subjects
Details
- Language :
- English
- ISSN :
- 1551-4005
- Volume :
- 6
- Issue :
- 16
- Database :
- MEDLINE
- Journal :
- Cell cycle (Georgetown, Tex.)
- Publication Type :
- Academic Journal
- Accession number :
- 17721077
- Full Text :
- https://doi.org/10.4161/cc.6.16.4526