Optimizing an experimental approach to silence disease-related genes by interfering with their chromatin structure. Epigenetic silencing of the human androgen receptor.

In this CREA-project, we aim to develop methods to induce alterations in the chromatin structure at a specific locus in the genome, to shut down one singe gene. Three approaches will be testen: (1) expression of shRNAs, (2) expression of non-coding RNAs and (3) transfection of methylated oligonucleotides. Epigenetic silencing by these mechanisms has been described for other test organisms, but has not been testen thoroughly in human/mammalian cells. Such "epigenetic therapy" has the advantage that it acts before the gene is actually expressed, preventing the protein from appearing. The use of mRNA targeting siRNAs to experimentally control protein levels has only short term effects, since they target the mRNA which is continuously synthesized as long as the gene is active. In contrast, a transient exposure to an epigenetic modifying agent is expected to suffice for the stable shut down of the gene. The changed epigenome will even be inherited by the daughter cells. During the two years of this CREA project, we will test the possibility to shut down the expression of the androgen receptor gene in prostate cancer cells. Prostate cancer is the most common cancer excluding skin cancer, and the second leading cause of cancer-related dead. It is likely to become a more promiment and pressing problem as the percentage of elderly men increases. Current treatments have severe side effects and a high chance for recurrence. Therefore, the need for development of new highly effective therapies with a small impact on the quality-of-life and minimal side effects is obvious. The fact that the AR is crucial for both the initiation and maintenance of prostate cancer makes it the ideal target for therapy. It has been shown that the knock down of androgen receptor (AR) expression at the mRNA level, leads to cell death of prostate cancer cells. Our approach is innovative because silencing the AR promoter depletes the cell of AR protein. This may enhance the benefits of androgen ablation by reducing of preventing AR cross activation by other ligands and other signaling pathways. Our new epigenetic silencing protocol will be a major step forward in the treatment of prostate cancer. When our approach is successful, we plan to target other genes with a proven role in prostate and/or other cancers, such as oncogenes or tumor survival genes. Of course the same protocols will be useful in fundamental research in which shutting down specific genes (cfr. knock out) has provided many insights in protein functions.

Keywords:RNA, Chromatine, DNA methylation, Epigenetics, TMPRSS2, Androgen receptor, Prostate cancer

Disciplines:Other biological sciences