Deregulation of microRNA (miRNA) expression can have a critical role in carcinogenesis.
Here we show in prostate cancer that miRNA-205 (miR-205) transcription is commonly repressed and the MIR-205 locus is hypermethylated. LOC642587, the MIR-205 host gene of unknown function, is also concordantly inactivated. We show that miR-205 targets mediator 1 (MED1, also called TRAP220 and PPARBP) for transcriptional silencing in normal prostate cells, leading to reduction in MED1 mRNA levels, and in total and active phospho-MED1 protein. Overexpression of miR-205 in prostate cancer cells negatively affects cell viability, consistent with a tumor suppressor function. We found that hypermethylation of the MIR-205 locus was strongly related with a decrease in miR-205 expression and an increase in MED1 expression in primary tumor samples (n=14), when compared with matched normal prostate (n=7). An expanded patient cohort (tumor n=149, matched normal n=30) also showed significant MIR-205 DNA methylation in tumors compared with normal, and MIR-205 hypermethylation is significantly associated with biochemical recurrence (hazard ratio=2.005, 95% confidence interval (1.109, 3.625), P=0.02), in patients with low preoperative prostate specific antigen. In summary, these results suggest that miR-205 is an epigenetically regulated tumor suppressor that targets MED1 and may provide a potential biomarker in prostate cancer management
Written by:
Hulf T, Sibbritt T, Wiklund ED, Patterson K, Song JZ, Stirzaker C, Qu W, Nair S, Horvath LG, Armstrong NJ, Kench JG, Sutherland RL, Clark SJ. Are you the author?
Epigenetics Group, Cancer Research Program, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia.
Reference: Oncogene. 2012 Aug 6. Epub ahead of print.
doi: 10.1038/onc.2012.300
PubMed Abstract
PMID: 22869146
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