DNA methyl transferase 1 reduces expression of SRD5A2 in the aging adult prostate.

5-α Reductase type 2 (SRD5A2) is a critical enzyme for prostatic development and growth. Inhibition of SRD5A2 by finasteride is used commonly for the management of urinary obstruction caused by benign prostatic hyperplasia. Contrary to common belief, we have found that expression of SRD5A2 is variable and absent in one third of benign adult prostates. In human samples, absent SRD5A2 expression is associated with hypermethylation of the SRD5A2 promoter, and in vitro SRD5A2 promoter activity is suppressed by methylation. We show that methylation of SRD5A2 is regulated by DNA methyltransferase 1, and inflammatory mediators such as tumor necrosis factor α, NF-κB, and IL-6 regulate DNA methyltransferase 1 expression and thereby affect SRD5A2 promoter methylation and gene expression. Furthermore, we show that increasing age in mice and humans is associated with increased methylation of the SRD5A2 promoter and concomitantly decreased protein expression. Artificial induction of inflammation in prostate primary epithelial cells leads to hypermethylation of the SRD5A2 promoter and silencing of SRD5A2, whereas inhibition with tumor necrosis factor α inhibitor reactivates SRD5A2 expression. Therefore, expression of SRD5A2 is not static and ubiquitous in benign adult prostate tissues. Methylation and expression of SRD5A2 may be used as a gene signature to tailor therapies for more effective treatment of prostatic diseases.

Age and Obesity Promote Methylation and Suppression of 5α-Reductase 2: Implications for Personalized Therapy of Benign Prostatic Hyperplasia.

PURPOSE: In men with symptomatic benign prostatic hyperplasia 5α-reductase inhibitors are a main modality of treatment. More than 30% of men do not respond to the therapeutic effects of 5α-reductase inhibitors. We have found that a third of adult prostate samples do not express 5α-reductase type 2 secondary to epigenetic modifications. We evaluated whether 5α-reductase type 2 expression in benign prostatic hyperplasia specimens from symptomatic men was linked to methylation of the 5α-reductase type 2 gene promoter. We also identified associations with age, obesity, cardiac risk factors and prostate specific antigen. MATERIALS AND METHODS: Prostate samples from men undergoing transurethral prostate resection were used. We determined 5α-reductase type 2 protein expression and gene promoter methylation status by common assays. Clinical variables included age, body mass index, hypertension, hyperlipidemia, diabetes, prostate specific antigen and prostate volume. Univariate and multivariate statistical analyses were performed followed by stepwise logistic regression modeling. RESULTS: Body mass index and age significantly correlated with methylation of the 5α-reductase type 2 gene promoter (p <0.05) whereas prostate volume, prostate specific antigen or benign prostatic hyperplasia medication did not correlate. Methylation highly correlated with 5α-reductase protein expression (p <0.0001). In a predictive model increasing age and body mass index significantly predicted methylation status and protein expression (p <0.01). CONCLUSIONS: Increasing age and body mass index correlate with increased 5α-reductase type 2 gene promoter methylation and decreased protein expression in men with symptomatic benign prostatic hyperplasia. These results highlight the interplay among age, obesity and gene regulation. Our findings suggest an individualized epigenetic signature for symptomatic benign prostatic hyperplasia, which may be important to choose appropriate personalized treatment options.

Personalized medicine for the management of benign prostatic hyperplasia.

PURPOSE: Benign prostatic hyperplasia affects more than 50% of men by age 60 years, and is the cause of millions of dollars in health care expenditure for the treatment of lower urinary tract symptoms and urinary obstruction. Despite the widespread use of medical therapy, there is no universal therapy that treats all men with symptomatic benign prostatic hyperplasia. At least 30% of patients do not respond to medical management and a subset require surgery. Significant advances have been made in understanding the natural history and development of the prostate, such as elucidating the role of the enzyme 5α-reductase type 2, and advances in genomics and biomarker discovery offer the potential for a more targeted approach to therapy. We review the current understanding of benign prostatic hyperplasia progression as well as the key genes and signaling pathways implicated in the process such as 5α-reductase. We also explore the potential of biomarker screening and gene specific therapies as tools to risk stratify patients with benign prostatic hyperplasia and identify those with symptomatic or medically resistant forms. MATERIALS AND METHODS: A PubMed® literature search of current and past peer reviewed literature on prostate development, lower urinary tract symptoms, benign prostatic hyperplasia pathogenesis, targeted therapy, biomarkers, epigenetics, 5α-reductase type 2 and personalized medicine was performed. An additional Google Scholar™ search was conducted to broaden the scope of the review. Relevant reviews and original research articles were examined, as were their cited references, and a synopsis of original data was generated with the goal of informing the practicing urologist of these advances and their implications. RESULTS: Benign prostatic hyperplasia is associated with a state of hyperplasia of the stromal and epithelial compartments, with 5α-reductase type 2 and androgen signaling having key roles in the development and maintenance of the prostate. Chronic inflammation, multiple growth factor and hormonal signaling pathways, and medical comorbidities have complex roles in prostate tissue homeostasis as well as its evolution into the clinical state of benign prostatic hyperplasia. Resistance to medical therapy with finasteride may occur through silencing of the 5α-reductase type 2 gene by DNA methylation, leading to a state in which 30% of adult prostates do not express 5α-reductase type 2. Novel biomarkers such as single nucleotide polymorphisms may be used to risk stratify patients with symptomatic benign prostatic hyperplasia and identify those at risk for progression or failure of medical therapy. Several inhibitors of the androgen receptor and other signaling pathways have recently been identified which appear to attenuate benign prostatic hyperplasia progression and may offer alternative targets for medical therapy. CONCLUSIONS: Progressive worsening of lower urinary tract symptoms and bladder outlet obstruction secondary to benign prostatic hyperplasia is the result of multiple pathways including androgen receptor signaling, proinflammatory cytokines and growth factor signals. New techniques in genomics, proteomics and epigenetics have led to the discovery of aberrant signaling pathways, novel biomarkers, DNA methylation signatures and potential gene specific targets. As personalized medicine continues to develop, the ability to risk stratify patients with symptomatic benign prostatic hyperplasia, identify those at higher risk for progression, and seek alternative therapies for those in whom conventional options are likely to fail will become the standard of targeted therapy.