The Research On Reversing Expression Of Androgen Receptor In Androgen Receptor Negative Prostate Cancer Cell

Prostate cancer is a common tumor in man and the incidence increases gradually in recent fifteen years. Numerous experimental and clinical studies have proved that androgen plays an important role in the initiation and progression of prostate cancer. Approximately four fifth of prostate cancers express androgen receptor (AR+), and they are stimulated to grow by androgen. For these cancers, hormonal therapy includes androgen ablation or anti-androgen is usually effective. But after 18-24 months, part of these cancers will be not sensitive to hormonal therapy any longer. Some studies indicate the change form AR+ to AR- is the reason. Moreover, there remain one fifth of prostate cancers primarily lack the expression of AR protein (AR) and they are rarely responsive to hormonal therapy.Apparently, these AR" tumors lack AR gene expression, because of not only mutations within the AR gene but the loss of AR transcription. Studies have found that for AR-negative prostate cancer cells there are hypermethylated CpG islands in the AR gene promoter. Methylation of CpG islands in the gene promoter is believed to directly inhibit gene expression. So extensive methylation of CpG islands of the AR gene may play a role in the absence of AR gene expression in AR- human prostate...