Role of Androgen Receptor in Prostate Cancer: A Review

Androgen receptor (AR) is a steroid receptor transcriptional factor for testosterone and dihydrotestosterone consisting of four main domains, the N-terminal domain, DNA-binding domain, hinge region, and ligand-binding domain. AR plays pivotal roles in prostate cancer, especially castration-resistant prostate cancer (CRPC). Androgen deprivation therapy can suppress hormone-naïve prostate cancer, but prostate cancer changes AR and adapts to survive under castration levels of androgen. These mechanisms include AR point mutations, AR overexpression, changes of androgen biosynthesis, constitutively active AR splice variants without ligand binding, and changes of androgen cofactors. Studies of AR in CRPC revealed that AR was still active in CRPC, and it remains as a potential target to treat CRPC. Enzalutamide is a second-generation antiandrogen effective in patients with CRPC before and after taxane-based chemotherapy. However, CRPC is still incurable and can develop drug resistance. Understanding the mechanisms of this resistance can enable new-generation therapies for CRPC. Several promising new AR-targeted therapies have been developed. Apalutamide is a new Food and Drug Administration-approved androgen agonist binding to the ligand-binding domain, and clinical trials of other new AR-targeted agents binding to the ligand-binding domain or N-terminal domain are underway. This review focuses on the functions of AR in prostate cancer and the development of CRPC and promising new agents against CRPC.

Associations of homologous RNA-binding motif gene on the X chromosome (RBMX) and its like sequence on chromosome 9 (RBMXL9) with non-obstructive azoospermia / 亚洲男科学杂志(英文版)

<p><b>AIM</b>To investigate the associations of autosomal and X-chromosome homologs of the RNA-binding-motif (RNA-binding-motif on the Y chromosome, RBMY) gene with non-obstructive azoospermia (NOA), as genetic factors for NOA may map to chromosomes other than the Y chromosome.</p><p><b>METHODS</b>Genomic DNA was extracted using a salting-out procedure after treatment of peripheral blood leukocytes with proteinase K from Japanese patients with NOA (n=67) and normal fertile volunteers (n=105). The DNA were analyzed for RBMX by expressed sequence tag (EST) deletion and for the like sequence on chromosome 9 (RBMXL9) by microsatellite polymorphism.</p><p><b>RESULTS</b>We examined six ESTs in and around RBMX and found a deletion of SHGC31764 in one patient with NOA and a deletion of DXS7491 in one other patient with NOA. No deletions were detected in control subjects. The association study with nine microsatellite markers near RBMXL9 revealed that D9S319 was less prevalent in patients than in control subjects, whereas D9S1853 was detected more frequently in patients than that in control subjects.</p><p><b>CONCLUSION</b>We provide evidence that deletions in or around RBMX may be involved in NOA. In addition, analyses of markers in the vicinity of RBMXL9 on chromosome 9 suggest the possibility that variants of this gene may be associated with NOA. Although further studies are necessary, this is the first report of the association between RBMX and RBMXL9 with NOA.</p>