Deletions of the androgen-metabolizing UGT2B genes have an effect on circulating steroid levels and biochemical recurrence after radical prostatectomy in localized prostate cancer

Distilling functional variations for human UGT2B4 upstream region based on selection signals and implications for phenotypes of Neanderthal and Denisovan

Our previous work identified one region upstream human UGT2B4 (UDP glucuronosyltransferase family 2 member B4) which is associated with breast cancer and under balancing selection. However, the distribution, functional variation and molecular mechanism underlying breast cancer and balancing selection remain unclear. In current study, the two haplotypes with deep divergence are described by analyzing 1000 genomes project data and observed to be with high frequencies in all human populations. Through population genetics analysis and genome annotation, the potential functional region is identified and verified by reporter gene assay. Further mutagenesis indicates that the functional mutations are rs66862535 and rs68096061. Both SNPs can alter the interaction efficiency of transcription factor POU2F1 (POU class 2 homeobox 1). Through chromosome conformation capture, it is identified that the enhancer containing these two SNPs can interact with UGT2B4 promoter. Expression quantitative trait loci analysis indicates that UGT2B4 expression is dependent on the genotype of this locus. The common haplotype in human is lost in four genomes of archaic hominins, which suggests that Neanderthal and Denisovan should present relatively lower UGT2B4 expression and further higher steroid hormone level. This study provides new insight into the contribution of ancient population structure to human phenotypes.

UGT2B28 accelerates prostate cancer progression through stabilization of the endocytic adaptor protein HIP1 regulating AR and EGFR pathways

The androgen inactivating UGT2B28 pathway emerges as a predictor of progression in prostate cancer (PCa). However, the clinical significance of UGT2B28 tumoral expression and its contribution to PCa progression remain unclear. Using the Canadian Prostate Cancer Biomarker Network biobank (CPCBN; n = 1512), we analyzed UGT2B28 tumor expression in relation to clinical outcomes in men with localized PCa. UGT2B28 was overexpressed in tumors compared to paired normal adjacent prostatic tissue and was associated with inferior outcomes. Functional analyses indicated that UGT2B28 promoted cell proliferation, and its expression was regulated by the androgen receptor (AR)/ARv7. Mechanistically, UGT2B28 was shown to be a protein partner of the endocytic adaptor protein huntingtin-interacting protein 1 (HIP1), increasing its stability and priming AR/epidermal growth factor receptor (EGFR) pathways, leading to ERK1/2 activation triggering cell proliferation and epithelial-to-mesenchymal transition (EMT). HIP1 knockdown in UGT2B28 positive cells, and dual pharmacological targeting of AR and EGFR pathways, abolished cell proliferative advantages conferred by UGT2B28. In conclusion, UGT2B28 is a prognosticator of progression in localized PCa, regulates both AR and EGFR oncogenic signaling pathways via HIP1, and therefore can be therapeutically targeted by using combination of existing AR/EGFR inhibitors.

Extensive metabolic consequences of human glycosyltransferase gene knockouts in prostate cancer

BACKGROUND

Naturally occurring germline gene deletions (KO) represent a unique setting to interrogate gene functions. Complete deletions and differential expression of the human glycosyltransferase UGT2B17 and UGT2B28 genes are linked to prostate cancer (PCa) risk and progression, leukaemia, autoimmune and other diseases.

METHODS

The systemic metabolic consequences of UGT deficiencies were examined using untargeted and targeted mass spectrometry-based metabolomics profiling of carefully matched, treatment-naive PCa cases.

RESULTS

Each UGT KO differentially affected over 5% of the 1545 measured metabolites, with divergent metabolic perturbations influencing the same pathways. Several of the perturbed metabolites are known to promote PCa growth, invasion and metastasis, including steroids, ceramides and kynurenine. In UGT2B17 KO, reduced levels of inactive steroid-glucuronides were compensated by sulfated derivatives that constitute circulating steroid reservoirs. UGT2B28 KO presented remarkably lower levels of oxylipins paralleled by reduced inflammatory mediators, but higher ceramides unveiled as substrates of the enzyme in PCa cells.

CONCLUSION

The distinctive and broad metabolic rewiring caused by UGT KO reinforces the need to examine their unique and divergent functions in PCa biology.

Circulating and Intratumoral Adrenal Androgens Correlate with Response to Abiraterone in Men with Castration-Resistant Prostate Cancer

PURPOSE

In metastatic castration-resistant prostate cancer (mCRPC) low serum androgens prior to starting abiraterone acetate (AA) is associated with more rapid progression. We evaluated the effect of AA on androgens in castration-resistant prostate cancer (CRPC) metastases and associations of intratumoral androgens with response.

EXPERIMENTAL DESIGN

We performed a phase II study of AA plus prednisone in mCRPC. The primary outcome was tissue testosterone at 4 weeks. Exploratory outcomes were association of steroid levels and genomic alterations with response, and escalating AA to 2,000 mg at progression.

RESULTS

Twenty-nine of 30 men were evaluable. Testosterone in metastatic biopsies became undetectable at 4 weeks (P < 0.001). Serum and tissue dehydroepiandrosterone sulfate (DHEAS) remained detectable in many patients and was not increased at progression. Serum and tissue DHEAS in the lowest quartile (pretreatment), serum DHEAS in the lowest quartile (4 weeks), and undetectable tissue DHEAS (on-therapy) associated with rapid progression (20 vs. 48 weeks, P = 0.0018; 20 vs. 52 weeks, P = 0.0003; 14 vs. 40 weeks, P = 0.0001; 20 vs. 56 weeks, P = 0.02, respectively). One of 16 men escalating to 2,000 mg had a 30% PSA decline; 13 developed radiographic progression by 12 weeks. Among patients with high serum DHEAS at baseline, wild-type (WT) PTEN status associated with longer response (61 vs. 33 weeks, P = 0.02).

CONCLUSIONS

Low-circulating adrenal androgen levels are strongly associated with an androgen-poor tumor microenvironment and with poor response to AA. Patients with CRPC with higher serum DHEAS levels may benefit from dual androgen receptor (AR)-pathway inhibition, while those in the lowest quartile may require combinations with non-AR-directed therapy.

Altered glucuronidation deregulates androgen dependent response profiles and signifies castration resistance in prostate cancer

Glucuronidation controls androgen levels in the prostate and the dysregulation of enzymes in this pathway is associated with castration resistant prostate cancer. UDP-glucose dehydrogenase (UGDH) produces UDP-glucuronate, the essential precursor for glucuronidation, and its expression is elevated in prostate cancer. We compared protein and metabolite levels relevant to the glucuronidation pathway in five prostate cancer patient-derived xenograft models paired with their isogenic counterparts that were selected in vivo for castration resistant (CR) recurrence. All pairs showed changes in UGDH and associated enzymes and metabolites that were consistent with those we found in an isogenic androgen dependent (AD) and CR LNCaP prostate cancer model. Ectopic overexpression of UGDH in LNCaP AD cells blunted androgen-dependent gene expression, increased proteoglycan synthesis, significantly increased cell growth compared to controls, and eliminated dose responsive growth suppression with enzalutamide treatment. In contrast, the knockdown of UGDH diminished proteoglycans, suppressed androgen dependent growth irrespective of androgens, and restored androgen sensitivity in CR cells. Importantly, the knockdown of UGDH in both LNCaP AD and CR cells dramatically sensitized these cells to enzalutamide. These results support a role for UGDH in androgen responsiveness and a target for therapeutic strategies in advanced prostate cancer.

Adenoid cystic carcinoma and chronic lymphocytic leukaemia: synchronous presentations in the lung

A 59-year-old male active smoker presented with a 6-month history of cough and breathlessness and was found to have a right upper lobe mass. Histology revealed this to be an adenoid cystic carcinoma (ACC) of the lung, while local lymph node dissection revealed a synchronous diagnosis of chronic lymphocytic leukaemia (CLL). The connection between CLL and solid organ malignancy is well documented, but the reporting of ACC in this context is novel. Mechanisms linking the two processes are revealed with the possibility of causality, and heightened vigilance for the development of primary lung tumours in CLL, and their management, is recommended.

Gonadotropin-releasing hormone agonists, anti-androgens and the risk of cardio-cerebrovascular disease in prostate cancer patients: an asian population-based observational study

Purpose: To conduct a population-based study to determine whether the use of GnRH agonist and antiandrogens are associated with an increased risk of cardio-cerebrovascular disease (CCVD) in Asian patients with prostate cancer using the National Health Insurance Service-Elderly Cohort Database (NHIS-ECD). Materials and Methods: We included a total of 2,413 men aged 60 years or older with prostate cancer between January 2003 and December 2008. Outcomes of interest included the first occurrence of cardiovascular events [acute myocardial infarction (AMI), ischemic heart disease (IHD)] and cerebrovascular events [ischemic stroke (IS), and cerebrovascular disease (CVD)]. Results: The 5-year AMI-free rates of patients diagnosed with prostate cancer and treated with GnRH agonists, antiandrogens alone, or androgen deprivation therapy (ADT)-naïve interventions were 97.0%, 96.5%, and 98.3%, respectively, while the 5-year IHD-free rates were 93.2%, 92.3%, and 94.5%, respectively. Exposure to GnRH agonists or antiandrogen regimens did not significantly increase the risk of AMI or IHD compared to ADT-naïve treatment in multivariate Cox proportional-hazards models after adjusting for other covariates. Five-year IS-free rates of patients exposed to GnRH agonists, antiandrogens alone, and those with ADT-naïve prostate cancer were 94.8%, 94.7%, and 95.5%, respectively, while the five-year CVD-free rates were 92.9%, 93.3%, and 94.6%, respectively. Cox proportional-hazards models also failed to show that men who received GnRH agonist or antiandrogen treatment alone carried a significantly increased risk for IS or CVD compared to ADT-naïve patients. Conclusions: The current study based on Asian population suggests that treatment with neither GnRH agonist nor antiandrogens increases the risk of cardio-cerebrovascular disease compared to patients with ADT-naïve prostate cancer.

Emerging roles for UDP-glucuronosyltransferases in drug resistance and cancer progression

The best-known role of UDP-glucuronosyltransferase enzymes (UGTs) in cancer is the metabolic inactivation of drug therapies. By conjugating glucuronic acid to lipophilic drugs, UGTs impair the biological activity and enhance the water solubility of these agents, driving their elimination. Multiple clinical observations support an expanding role for UGTs as modulators of the drug response and in mediating drug resistance in numerous cancer types. However, accumulating evidence also suggests an influence of the UGT pathway on cancer progression. Dysregulation of the expression and activity of UGTs has been associated with the progression of several cancers, arguing for UGTs as possible mediators of oncogenic pathways and/or disease accelerators in a drug-naive context. The consequences of altered UGT activity on tumour biology are incompletely understood. They might be associated with perturbed levels of bioactive endogenous metabolites such as steroids and bioactive lipids that are inactivated by UGTs or through non-enzymatic mechanisms, thereby eliciting oncogenic signalling cascades. This review highlights the evidence supporting dual roles for the UGT pathway, affecting cancer progression and drug resistance. Pharmacogenomic testing of UGT profiles in patients and the development of therapeutic options that impair UGT actions could provide useful prognostic and predictive biomarkers and enhance the efficacy of anti-cancer drugs.

Functional genomic studies reveal the androgen receptor as a master regulator of cellular energy metabolism in prostate cancer

Sex-steroid hormones have been investigated for decades for their oncogenic properties in hormone-dependent cancers. The increasing body of knowledge on the biological actions of androgens in prostate cancer has led to the development of several targeted therapies that still represent the standard of care for cancer patients to this day. In the prostate, androgens promote cellular differentiation and proper tissue development. These hormones also promote the aberrant proliferation and survival of prostate cancer cells. Over the past few years, sequencing technologies for functional genomic analyses have rapidly expanded, revealing novel functions of sex-steroid hormone receptors other than their classic roles. In this article, we will focus on transcriptomic- and genomic-based evidence that demonstrates the importance of the androgen receptor signaling in the regulation of prostate cancer cell metabolism. This is significant because the reprogramming of cell metabolism is a hallmark of cancer. In fact, it is clear now that the androgen receptor contributes to the reprogramming of specific cellular metabolic pathways that promote tumor growth and disease progression, including aerobic glycolysis, mitochondrial respiration, fatty acid ß-oxidation, and de novo lipid synthesis. Overall, beyond regulating development, differentiation, and proliferation, the androgen receptor is also a master regulator of cellular energy metabolism.

The UDP-Glycosyltransferase (UGT) Superfamily: New Members, New Functions, and Novel Paradigms

UDP-glycosyltransferases (UGTs) catalyze the covalent addition of sugars to a broad range of lipophilic molecules. This biotransformation plays a critical role in elimination of a broad range of exogenous chemicals and by-products of endogenous metabolism, and also controls the levels and distribution of many endogenous signaling molecules. In mammals, the superfamily comprises four families: UGT1, UGT2, UGT3, and UGT8. UGT1 and UGT2 enzymes have important roles in pharmacology and toxicology including contributing to interindividual differences in drug disposition as well as to cancer risk. These UGTs are highly expressed in organs of detoxification (e.g., liver, kidney, intestine) and can be induced by pathways that sense demand for detoxification and for modulation of endobiotic signaling molecules. The functions of the UGT3 and UGT8 family enzymes have only been characterized relatively recently; these enzymes show different UDP-sugar preferences to that of UGT1 and UGT2 enzymes, and to date, their contributions to drug metabolism appear to be relatively minor. This review summarizes and provides critical analysis of the current state of research into all four families of UGT enzymes. Key areas discussed include the roles of UGTs in drug metabolism, cancer risk, and regulation of signaling, as well as the transcriptional and posttranscriptional control of UGT expression and function. The latter part of this review provides an in-depth analysis of the known and predicted functions of UGT3 and UGT8 enzymes, focused on their likely roles in modulation of levels of endogenous signaling pathways.

Whole exome sequencing identifies hemizygous deletions in the UGT2B28 and USP17L2 genes in a three‑generation family with endometriosis

Endometriosis is an enigmatic condition with an unknown etiology and a poorly understood pathogenesis. It is considered to appear from the interplay of many genetic and environmental factors, affecting up to 10% of women and represents a major cause of pain and infertility. The familial association of endometriosis, as demonstrated through monozygotic twin and family studies suggests a genetic contribution to the disease, with further case-control and genome-wide association studies (GWAS) detecting various endometriosis risk factors. In a recent study, we described a unique, three-generation family of Cretan origin (Greece) with 7 females with surgically confirmed endometriosis (grandmother, 3 daughters and 3 granddaughters). All the affected members of this family displayed a variety of clinical manifestations and complications. In the present study, to further analyze the genetic variants conferring the risk of developing endometriosis, whole exome sequencing (WES) was performed, using the AmpliSeq technology on the Ion Proton platform. An initial analysis of 64 variants that were detected across the 14 genes previously confirmed to be associated with endometriosis, did not identify any deleterious exonic variants in these genes. However, further analysis revealed 2 hemizygous deletions in the grandmother that segregate in several of her affected offspring. The first deletion was found in the UGT2B28 locus, spanning 7 informative sequence variants across at least 14 kb. The second deletion, located in USP17L2, spans 3 informative variants across at least 2 kb. On the whole, the findings of the presents study implicate 2 additional genes in the pathogenesis of endometriosis, apart from those already identified by GWAS.

A Novel Mechanism to Drive Castration-Resistant Prostate Cancer

Androgen receptor signaling is critical for prostate adenocarcinoma, even after androgen deprivation therapy. Persistence of intratumoral androgens has been found in castration-resistant prostate cancer and attributed to increased in situ synthesis. Recently, Sharifi and colleagues reported an additional mechanism that can enhance local androgenic exposure: downregulation of an androgen-inactivating enzyme.

Sex-dependent association of circulating sex steroids and pituitary hormones with treatment-free survival in chronic lymphocytic leukemia patients

Chronic lymphocytic leukemia (CLL) is not considered a hormone-regulated cancer although sex is a recognized risk factor with men more frequently diagnosed and developing progressive disease. We hypothesized that variable hormonal exposure may have a sexually dimorphic influence on treatment-free survival (TFS). In 156 CLL cases, we quantitatively profiled 29 circulating steroids (progesterone, adrenal precursors, androgens, estrogens, and catechol estrogens) as well as luteinizing hormone (LH) and follicle-stimulating hormone. Median TFS was shorter for men than that for women (80.7 vs. 135.0 months, P = 0.033). Circulating hormone profiles in CLL patients were significantly different from those of healthy donors. In male CLL cases, higher LH levels were associated with shorter TFS (adjusted hazard ratio (HR_adj) 2.11; P = 0.004). In female CLL cases, high levels of the potent androgens testosterone and dihydrotestosterone and the sum of methoxy estrogens were associated with an improved TFS with HR_adj values of 0.24 (P = 0.007), 0.54 (P = 0.023), and 0.31 (P = 0.034), respectively. Reduced TFS was observed for women with CLL exhibiting high expression of the steroid-inactivating UGT2B17 enzyme. This study is the first to establish a link between the outcome of CLL patients, sex steroids, and pituitary hormones, revealing a sex-specific hormonal imbalance associated with disease progression.

Intracrine androgen biosynthesis, metabolism and action revisited

Androgens play an important role in metabolic homeostasis and reproductive health in both men and women. Androgen signalling is dependent on androgen receptor activation, mostly by testosterone and 5α-dihydrotestosterone. However, the intracellular or intracrine activation of C₁₉ androgen precursors to active androgens in peripheral target tissues of androgen action is of equal importance. Intracrine androgen synthesis is often not reflected by circulating androgens but rather by androgen metabolites and conjugates. In this review we provide an overview of human C₁₉ steroid biosynthesis including the production of 11-oxygenated androgens, their transport in circulation and uptake into peripheral tissues. We conceptualise the mechanisms of intracrinology and review the intracrine pathways of activation and inactivation in selected human tissues. The contribution of liver and kidney as organs driving androgen inactivation and renal excretion are also highlighted. Finally, the importance of quantifying androgen metabolites and conjugates to assess intracrine androgen production is discussed.

Sex steroids in the tumor microenvironment and prostate cancer progression

Prostate cancer is uniquely dependent on androgens. Despite years of research on the relationship between androgens and prostate cancer, many questions remain as to the biological effects of androgens and other sex steroids during prostate cancer progression. This article reviews the clinical and basic research on the influence of sex steroids such as androgens, estrogens and progesterone within the prostate tumor microenvironment on the progression of prostate cancer. We review clinical studies to date evaluating serum sex steroids as prognostic biomarkers and discuss their respective biological effects within the prostate tumor microenvironment. We also review the link between genomic alterations and sex steroid levels within prostate tumors. Finally, we highlight the links between sex steroid levels and the function of the immune system within the tumor microenvironment. As the context of treatment of lethal prostate cancer evolves over time, an understanding of this underlying biology remains central to developing optimal treatment approaches.

Regulation of Hepatic UGT2B15 by Methylation in Adults of Asian Descent

The hepatic uridine 5'-diphosphate-glucuronosyl transferases (UGTs) are critical for detoxifying endo- and xenobiotics. Since UGTs are also dynamically responsive to endogenous and exogenous stimuli, we examined whether epigenetic DNA methylation can regulate hepatic UGT expression and differential effects of ethnicity, obesity, and sex. The methylation status of UGT isoforms was determined with Illumina Methylation 450 BeadChip arrays, with genotyping confirmed by sequencing and gene expression confirmed with quantitative reverse transcriptase polymerase chain reaction (q-RT-PCR). The UGT1A3 mRNA was 2-fold higher in females than males (p < 0.05), while UGT1A1 and UGT2B7 mRNA were significantly higher in Pacific Islanders than Caucasians (both p < 0.05). Differential mRNA or methylation did not occur with obesity. The methylation of the UGT2B15 locus cg09189601 in Caucasians was significantly lower than the highly methylated locus in Asians (p < 0.001). Three intergenic loci between UGT2B15 and 2B17 (cg07973162, cg10632656, and cg07952421) showed higher rates of methylation in Caucasians than in Asians (p < 0.001). Levels of UGT2B15 and UGT2B17 mRNA were significantly lower in Asians than Caucasians (p = 0.01 and p < 0.001, respectively). Genotyping and sequencing indicated that only UGT2B15 is regulated by methylation, and low UGT2B17 mRNA is due to a deletion genotype common to Asians. Epigenetic regulation of UGT2B15 may predispose Asians to altered drug and hormone metabolism and begin to explain the increased risks for adverse drug reactions and some cancers in this population.

Genetic variations in UGT2B28, UGT2B17, UGT2B15 genes and the risk of prostate cancer: A case-control study

Glucuronidation is a major pathway for elimination of exogenous and endogenous compounds such as environmental carcinogens and androgens from the body. This biochemical pathway is mediated by enzymes called uridine diphosphoglucuronosyltransferases (UGTs). Null (del/del) genes polymorphisms in UGT2B17, and UGT2B28 and D85Y single-nucleotide polymorphism (SNP) of UGT2B15 have been reported to increase the risk of prostate cancer. The goal of this study was to determine the association of mentioned genetic variants with the risk of prostate cancer. We investigated the copy number variations (CNVs) of UGT2B17 and UGT2B28 loci and the association between rs1902023 polymorphism of UGT2B15 gene in 360 subjects consisted of 120 healthy controls, 120 prostate cancer (PC) patients and 120 benign prostatic hyperplasia (BPH) patients. No association was detected for the mentioned polymorphisms and the risk of PC. However, a significant association was detected between UGT2B17 copy number variation and BPH risk (OR=2.189; 95% CI, 1.303-3.675; p=0.003). Furthermore, we observed that the D85Y polymorphism increases the risk of BPH when analyzed in combination with the copy number variation of UGT2B17 gene (OR=0.135; 95% CI, 0.036-0.512; p=0.003). Our findings suggest that the D85Y polymorphism of UGT2B15 and CNVs in UGT2B28 and UGT2B17 genes is not associated with prostate cancer risk in Iranian patients. To our knowledge, this is the first report that implicates the role of CNV of UGT2B17 gene in BPH.

UDP-glucuronosyltransferases and biochemical recurrence in prostate cancer progression

Background

Uridine 5′-diphosphate-glucuronosyltransferase 2B (UGT2B) genes code for enzymes that catalyze the clearance of testosterone, dihydrotestosterone (DHT), and DHT metabolites in the prostate basal and luminal tissue. The expression of the UGT2B15, UGT2B17, and UGT2B28 enzymes has not been evaluated in prostate tissue samples from hormone therapy-naïve patients.

Methods

We determined the expression of UGT2B15, UGT2B17, and UGT2B28 enzymes in 190 prostate tissue samples from surgical specimens of a multiethnic cohort of patients undergoing radical prostatectomy at the Durham Veterans Affairs Medical Center. The association between each protein’s percent positive and H-score, a weighted score of staining intensity, and the risk of biochemical recurrence (BCR) was tested using separate Cox proportional hazards models. In an exploratory analysis, UGT2B17 total positive and H-score were divided at the median and we tested the association between UGT2B17 group and risk of BCR.

Results

The median follow-up for all patients was 118 months (IQR: 85-144). Of 190, 83 (44%) patients developed BCR. We found no association between UGT2B15 or UGT2B28 and risk of BCR. However, there was a trend for an association between UGT2B17 and BCR (HR = 1.01, 95% CI 1.00-1.02, p = 0.11), though not statistically significant. Upon further investigation, we found that patients with UGT2B17 higher levels of expression had a significant increased risk of BCR on univariable analysis (HR = 1.57, 95% CI 1.02-2.43, p = 0.041), although this association was attenuated in the multivariable model (HR = 1.50, 95% CI 0.94-2.40, p = 0.088).

Conclusions

Our findings suggest that UGT2B17 overexpression may be associated with a significant increased risk of BCR. These results are consistent with previous reports which showed UGT2B17 significantly expressed in advanced prostate cancer including prostate tumor metastases.

Inverse Regulation of DHT Synthesis Enzymes 5α-Reductase Types 1 and 2 by the Androgen Receptor in Prostate Cancer

5α-Reductase types 1 and 2, encoded by SRD5A1 and SRD5A2, are the two enzymes that can catalyze the conversion of testosterone to dihydrotestosterone, the most potent androgen receptor (AR) agonist in prostate cells. 5α-Reductase type 2 is the predominant isoform expressed in the normal prostate. However, its expression decreases during prostate cancer (PCa) progression, whereas SRD5A1 increases, and the mechanism underlying this transcriptional regulatory switch is still unknown. Interrogation of SRD5A messenger RNA expression in three publicly available data sets confirmed that SRD5A1 is increased in primary and metastatic PCa compared with nontumoral prostate tissues, whereas SRD5A2 is decreased. Activation of AR, a major oncogenic driver of PCa, induced the expression of SRD5A1 from twofold to fourfold in three androgen-responsive PCa cell lines. In contrast, AR repressed SRD5A2 expression in this context. Chromatin-immunoprecipitation studies established that AR is recruited to both SRD5A1 and SRD5A2 genes following androgen stimulation but initiates transcriptional activation only at SRD5A1 as monitored by recruitment of RNA polymerase II and the presence of the H3K27Ac histone mark. Furthermore, we showed that the antiandrogens bicalutamide and enzalutamide block the AR-mediated regulation of both SRD5A1 and SRD5A2, highlighting an additional mechanism explaining their beneficial effects in patients. In summary, we identified an AR-dependent transcriptional regulation that explains the differential expression of 5α-reductase types 1 and 2 during PCa progression. Our work thus defines a mechanism by which androgens control their own synthesis via differential regulatory control of the expression of SRD5A1 and SRD5A2.

Cardiovascular risk after androgen deprivation therapy for prostate cancer: an Asian perspective

Androgen deprivation therapy (ADT) plays an important role in managing prostate cancer. However, ADT may result in major cardiovascular events and potentially lead to fatal consequences. Cardiovascular disease is the leading cause of mortality and it is a very important health condition to look into. Asians and Caucasians differ both physiologically and genetically, and they may have display different cardiovascular profiles. In this article, we reviewed the literature focusing on the cardiovascular risk after ADT for prostate cancer in the Asian population. We would discuss about the pathogenesis of ADT leading to cardiovascular events, summarize the findings concerning cardiac and stroke risks after ADT, compare between the different modalities of ADT and also provide genetic basics which are unique to Asians. We hope this article would provide more insights into the cardiovascular risk after ADT for prostate cancer in an Asian perspective.

New insights into the androgen biotransformation in prostate cancer: A regulatory network among androgen, androgen receptors and UGTs

Androgen, as one kind of steroid hormones, is pivotal in the hormone-sensitive cancer, such as prostate cancer (PCa). The synthesis, elimination, and bioavailability of androgen in prostate cells have been proved to be a main cause of the carcinogenesis, maintenance and deterioration of PCa. This review illustrates the outlines of androgen biotransformation, and further discusses the different enzymes, especially UDP-glucuronyltransferases (UGTs) embedded in both benign and malignant prostate cells, which catalyze the reactions. Although many inhibitors of the enzymes responsible for the synthesis of androgens have been developed into drugs to fight against PCa, the elimination procedures metabolized by the UGTs are less emphasized. Thus the regulatory network among androgen, androgen receptors (AR) and UGTs is carefully reviewed in this article, indicating the determinant effects of UGTs on prostatic androgens and the regulation of AR. Finally, the hypothesis is also put forward that the regulators of UGTs may be developed to accelerate the androgen elimination and benefit PCa therapy.

Classical and Non-Classical Roles for Pre-Receptor Control of DHT Metabolism in Prostate Cancer Progression

Androgens play an important role in prostate cancer (PCa) development and progression. Accordingly, androgen deprivation therapy remains the front-line treatment for locally recurrent or advanced PCa, but patients eventually relapse with the lethal form of the disease termed castration resistant PCa (CRPC). Importantly, castration does not eliminate androgens from the prostate tumor microenvironment which is characterized by elevated tissue androgens that are well within the range capable of activating the androgen receptor (AR). In this mini-review, we discuss emerging data that suggest a role for the enzymes mediating pre-receptor control of dihydrotestosterone (DHT) metabolism, including AKR1C2, HSD17B6, HSD17B10, and the UGT family members UGT2B15 and UGT2B17, in controlling intratumoral androgen levels, and thereby influencing PCa progression. We review the expression of steroidogenic enzymes involved in this pathway in primary PCa and CRPC, the activity and regulation of these enzymes in PCa experimental models, and the impact of genetic variation in genes mediating pre-receptor DHT metabolism on PCa risk. Finally, we discuss recent data that suggests several of these enzymes may also play an unrecognized role in CRPC progression separate from their role in androgen inactivation.

Epigenetic regulation of steroid inactivating UDP-glucuronosyltransferases by microRNAs in prostate cancer

Androgens play a central role in prostate cancer progression. Systemic and local androgen bioavailability is controlled by UDP-glucuronosyltransferases conjugating enzymes (UGT), namely UGT2B15, UGT2B17 and UGT2B28. Reporter vector assays in HEK293 cells initially validated in silico-predicted regulatory potential of candidate miRNAs to target UGT transcripts, including miR-376c, miR-409 and miR-494 for UGT2B17, miR-331-5p and miR-376c for UGT2B15 while none were efficient for UGT2B28. miR-376c was shown as the most effective to downregulate UGT2B15 and UGT2B17 through interactions with a site conserved in both UGTs. Ectopic miR-376c expression in prostate cancer cells significantly reduced UGT2B15 and UGT2B17 expression (>32%; P<0.005) with a consequent decrease in dihydrotestosterone glucuronidation (-37%; P<0.001). Consistent with reduced androgen inactivation, ectopic expression of miR-376c changed expression of androgen responsive genes and enhanced cell proliferation with no effect on androgen receptor levels. Sustaining a role of miR-376c in the regulation of androgen-inactivating UGTs, its expression was significantly downregulated in prostatic tumors and further reduced in metastases (P<0.0001), whereas the opposite was observed for UGT2B15/17 (P=0.031). In high-grade tumors (Gleason ≥8), UGT2B15/17 and miR-376c were inversely correlated (r=-0.557; P=0.048) with also a significant relationship in metastases (r=-0.747; P=0.003). In line with a modification in androgen bioavailability, PSA mRNA levels were also negatively correlated to those of UGT2B15/17 (r=-0.573; P=0.01) but positively linked to levels of miR-376c (r=0.577; P=0.039). This study reveals that the androgen-inactivating UGT2B15 and UGT2B17 genes are direct targets of miR-376c and thus may influence steroid metabolism during prostate cancer progression.

A chromatography/tandem mass spectrometry method for the simultaneous profiling of ten endogenous steroids, including progesterone, adrenal precursors, androgens and estrogens, using low serum volume

Measurement of a large set of sex steroids in clinical epidemiology and laboratory research with reliable methods providing low quantification limits and using a limited volume of blood sample represents a significant challenge. We report a new validated gas chromatography selected reaction monitoring - tandem mass spectrometry assay (GC-MS/MS) for the simultaneous quantification of ten endogenous steroids including progesterone (PROG), dehydroepiandrosterone (DHEA), androstenediol (5-diol), androstenedione (4-dione), testosterone (T), dihydrotestosterone (DHT), androsterone (ADT), 5alpha-androstan-3beta-17beta-diol (3β-diol), estrone (E1) and estradiol (E2). After addition of stable isotope internal standards, the approach involved the combination of liquid-liquid extraction, derivatization and solid-phase extraction for injection into the GC system and multiple reaction monitoring (MRM). The method presents high reproducibility for all analytical parameters in 250 μl serum samples. The lower limit of quantification (LLOQ) were of 100 pg/ml for DHEA, 50 pg/ml for PROG, 5-diol, 4-dione and ADT, 30 pg/ml for T, 10 pg/ml for 3β-diol and DHT, 5 pg/ml for E1, and 1 pg/ml for E2. The applicability of the validated method to determine the concentrations of these 10 steroids was successfully tested on serum from men (n=15), premenopausal (n=10) and postmenopausal women (n=20), and is currently used for larger cancer-related epidemiology studies. One of the most considerable advantages over existing methods is the simultaneous determination of ten steroids in a limited volume of serum that will help conserve important clinical samples from existing biobanks.

Correlation of Sprouty1 and Jagged1 with aggressive prostate cancer cells with different sensitivities to androgen deprivation

Prostate cancer is a heterogeneous disease and thus, it is important to understand whether among the heterogeneous collection of cell types, androgen-deprivation insensitive cells exist prior to hormonal manipulation. We established several LNCaP subclones with distinct insensitivities to androgen deprivation from a parental LNCaP cell line. In the resulting clones, the sensitivity to androgen-deprivation negatively correlated with their PSA expression levels. In two of these clones, an androgen insensitive clone, LNCaP-cl1, and an androgen sensitive clone, LNCaP-cl5, the DNA copy number differed significantly, indicating that these clones contain genetically distinct cells. LNCaP-cl1 had higher PSA expression but lower invasiveness and tumor growth potential than LNCaP-cl5. The expression levels of two genes that are known to be regulated by miR-21, an androgen-regulated microRNA, Sprouty1 (SPRY1) and Jagged1 (JAG1) were significantly lower in LNCaP-cl1 than in LNCaP-cl5. Knocking down SPRY1 in LNCaP cells enhanced PSA expression and cell proliferation. JAG1 administration in LNCaP cells enhanced cell invasion and JAG1 knockdown in PC3 cells suppressed cell invasion and tumor formation. These results indicated that the expression differences in SPRY1 and JAG1 may contribute to the phenotypic differences between the LNCaP-cl1 and LNCaP-cl5 clones. In tissue samples, SPRY1 expression levels were significantly lower in prostate cancer patients with PSA recurrence after surgical treatment (P = 0.0076) and JAG1 expression levels were significantly higher in Gleason sum (GS) 8-9 disease than in GS 5-6 (P = 0.0121). In summary a random population of LNCaP cells comprises a heterogeneous group of cells with different androgen-deprivation sensitivities and potential for invasiveness.

Risk of new-onset diabetes after androgen deprivation therapy for prostate cancer in the Asian population

BACKGROUND

The associations of androgen deprivation therapy (ADT) with its adverse events in the Asian population remained largely unknown. We investigated the risk of new-onset diabetes mellitus (DM) after ADT for prostate cancer in the Asian population.

METHODS

All prostate cancer patients who were treated primarily with radical prostatectomy or radiotherapy, with or without further ADT from 2000 to 2009 were reviewed. Clinical parameters including age, clinical T stage, Gleason score, hypertension, dyslipidemia, impaired fasting glucose, ischemic heart disease, history of stroke, new-onset DM, follow-up duration, form and duration of ADT were reviewed. The risk of DM after ADT was analyzed with Kaplan-Meier method and multivariate Cox regression analysis.

RESULTS

A total of 388 patients were included, consisting of 169 patients in the non-ADT group and 219 patients in the ADT group. Upon Kaplan-Meier analysis, the ADT group had a higher risk of new-onset DM (P = 0.011). Upon multivariate Cox regression analysis, dyslipidemia (HR 2.32, 95% CI 1.07-5.00, P = 0.032), impaired fasting glucose (HR 5.92, 95% CI 1. 2.27-15.45, P < 0.001) and the use of ADT in the form of GnRH agonist (HR 3.34, 95% CI 1.19-9.39, P = 0.022) and bilateral orchiectomy (HR 6.49, 95% CI 1.48-28.55, P = 0.013) were associated with increased risk of new-onset DM.

CONCLUSIONS

There was increased risk of new-onset DM after ADT for prostate cancer in the Asian population. Regular screening of DM can be considered after the initiation of ADT, especially in patients with known history of dyslipidemia and impaired fasting glucose.

The UGT2B28 Sex-steroid Inactivation Pathway Is a Regulator of Steroidogenesis and Modifies the Risk of Prostate Cancer Progression

BACKGROUND

Androgen inactivation occurs mainly through the glucuronidation conjugative reaction mediated by UDP-glucuronosyltransferases (UGTs). This metabolic process is involved in the control of systemic and local androgen bioavailability.

OBJECTIVE

To examine the relationship among expression of the androgen-inactivating UGT2B28 enzyme, circulating steroid hormone levels, and clinical phenotype in prostate cancer (PCa).

DESIGN, SETTING, AND PARTICIPANTS

We conducted an analysis of a high-density prostate tumor tissue microarray consisting of 239 localized PCa cases. The study of 51 additional PCa patients with no copies of UDP glucuronosyltransferase 2B subfamily, polypeptide B28 (UGT2B28) in their genomes was performed to confirm the importance of the enzyme on circulating hormone levels.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Steroid hormones were measured by mass spectrometry. Multivariate Cox proportional hazard models assessed the influence of UGT2B28 on progression, and general linear model regression evaluated variations in hormone levels.

RESULTS AND LIMITATIONS

Tumor overexpression of UGT2B28 was associated with lower prostate-specific antigen levels at diagnosis, higher Gleason scores, margin and nodal invasion status, and it was shown to be an independent prognostic factor associated with progression. Enzyme overexpression correlated with 30% higher circulating levels of testosterone (T) and dihydrotestosterone (DHT). Patients with no copies of UGT2B28 in their genomes have lower levels of T (19%), DHT (17%), its glucuronide metabolites (18-38%), and enhanced levels of the adrenal precursor androstenedione (36%).

CONCLUSIONS

The UGT2B28 steroid-inactivating pathway modifies circulating T and DHT levels, and UGT2B28 overexpression is associated with high-grade PCa. Our work has uncovered the role of UGT2B28 as a regulator of steroidogenesis and underscores the interconnectivity among the steroid-inactivation capacity of cancer cells, hormone levels, disease characteristics, and the risk of cancer progression.

PATIENT SUMMARY

The androgen-inactivating UGT2B28 enzyme influences hormone levels, clinical and pathologic factors, and the risk of cancer progression.

Impacts of the Glucuronidase Genotypes UGT1A4, UGT2B7, UGT2B15 and UGT2B17 on Tamoxifen Metabolism in Breast Cancer Patients

Tamoxifen is used to prevent and treat estrogen-dependent breast cancer. It is described as a prodrug since most of its antiestrogen effects are exerted through its hydroxylated metabolites 4-OH-tamoxifen and endoxifen. In prior work, we correlated optimal plasma levels of these metabolites with certain genotypes of CYP2D6 and SULT1A2. This descriptive study examines correlations between concentrations of tamoxifen's glucuronide metabolites and genotypes UGT1A4 Pro24Thr, UGT1A4 Leu48Val, UGT2B7 His268Tyr, UGT2B15 Asp85YTyr UGT2B15 Lys523Thr and UGT2B17del in 132 patients with estrogen receptor-positive breast cancer under treatment with tamoxifen. Patients were genotyped by real-time and conventional PCR-RFLP. The glucuronides 4-OH-tamoxifen-N-glucuronide, 4-OH-tamoxifen-O-glucuronide and endoxifen-O-glucuronide were isolated from blood plasma and quantified using a high-pressure liquid chromatography-tandem mass spectrometry system. Individuals who were homozygous for UGT1A448VAL showed significantly lower mean concentrations of both glucuronide metabolites compared to subjects genotyped as wt/wt plus wt/48Val (p=0.037 and p=0.031, respectively). Women homozygous for UGT2B7268Tyr also showed mean substrate/product ratios of 4-OH-tamoxifen/4-OH-tamoxifen-O-glucuronide and 4-OH-tamoxifen/4-OH-tamoxifen-N-glucuronide indicative of reduced glucuronidase activity compared to wt homozygotes or to heterozygotes for the polymorphism (p=0.005 and p=0.003, respectively). In contrast, UGT2B15 Lys523Thr and UGT2B17del were associated with possibly increased enzyme activity. Patients with at least one variant allele UGT2B15523Thr showed significantly higher 4-OH-tamoxifen-O-glucuronide and endoxifen-glucuronide levels (p=0.023 and p=0.025, respectively) indicating a variant gene-dose effect. Higher 4-OH-tamoxifen-N-glucuronide levels observed in UGT2B17del genotypes (p=0.042) could be attributed to a mechanism that compensates for the greater expression of other genes in UGT2B17 del/del individuals. Our observations suggest that patients carrying mutations UGT1A448Val, UGT2B7268Tyr or with wt genotypes for UGT2B17nodel and UGT2B15523Lys could be the best candidates for a good response to tamoxifen therapy in terms of eliciting effective plasma active tamoxifen metabolite levels. However, additional studies examining the effects of UGT genotype on overall patient response to TAM are needed to further examine the role of UGT polymorphisms in the therapeutic efficacy of TAM.

Risk of ischemic stroke after androgen deprivation therapy for prostate cancer in the Chinese population living in Hong Kong

OBJECTIVE

Previous reports on the risk of stroke after androgen deprivation therapy for prostate cancer were largely based on Caucasians. We investigated the risk of ischemic stroke after androgen deprivation therapy for prostate cancer in the Chinese population.

METHODS

All Chinese prostate cancer patients who were treated primarily with radical prostatectomy or radiotherapy, with (androgen deprivation therapy group) or without (non-androgen deprivation therapy group) further androgen deprivation therapy, at our hospital from year 2000-09 were reviewed. Potential risk factors of ischemic stroke including age, baseline prostate-specific antigen, Gleason score, clinical T stage, hypertension, diabetes mellitus, hyperlipidemia, ischemic heart disease, history of stroke, use of androgen deprivation therapy and duration of androgen deprivation therapy were reviewed. The risk of ischemic stroke after androgen deprivation therapy was analyzed with Kaplan-Meier and multivariate Cox regression analyses.

RESULTS

A total of 452 patients were included, consisting of 200 patients in the non-androgen deprivation therapy group and 252 patients in the androgen deprivation therapy group. The androgen deprivation therapy group appeared to have increased risk of ischemic stroke when compared with the non-androgen deprivation therapy group (P = 0.063) upon Kaplan-Meier analysis. Upon multivariate Cox regression analyses, older age (hazard ratio 1.13, 95% confidence interval 1.04-1.22, P = 0.003), hyperlipidemia (hazard ratio 4.61, 95% confidence interval 2.01-10.54, P < 0.001) and the use of androgen deprivation therapy (hazard ratio 3.32, 95% confidence interval 1.14-9.67, P = 0.028) were associated with increased risk of ischemic stroke.

CONCLUSIONS

There was increased risk of ischemic stroke after androgen deprivation therapy for prostate cancer in the Chinese population. The risk of ischemic stroke should be considered while deciding on androgen deprivation therapy, especially in older patients with known history of hyperlipidemia.

The UGT1 locus is a determinant of prostate cancer recurrence after prostatectomy

The prognostic significance of common deletions in uridine diphospho-glucuronosyltransferase 2B (UGT2B) genes encoding sex steroid metabolic enzymes has been recently recognized in localized prostate cancer (PCa) after radical prostatectomy (RP). However, the role of germline variations at the UGT1 locus, encoding half of all human UGTs and primarily involved in estrogen metabolism, remains unexplored. We investigated whether variants of UGT1 are potential prognostic markers. We studied 526 Caucasian men who underwent RP for clinically localized PCa. Genotypes of patients for 34 haplotype-tagged single-nucleotide polymorphisms (htSNPs) and 11 additional SNPs across the UGT1 locus previously reported to mark common variants including functional polymorphisms were determined. The risk of biochemical recurrence (BCR) was estimated using adjusted Cox proportional hazards regression and Kaplan-Meier analysis. We further investigated whether variants are associated with plasma hormone levels by mass spectrometry. In multivariable models, seven htSNPs were found to be significantly associated with BCR. A greater risk was revealed for four UGT1 intronic variants with hazard ratios (HRs) of 1.59-1.88 (P<0.002) for htSNPs in UGT1A10, UGT1A9, and UGT1A6. Conversely, decreased BCR was associated with three htSNPs in introns of UGT1A10 and UGT1A9 (HR=0.56-058; P≤0.01). An unfavorable UGT1 haplotype comprising all risk alleles, with a frequency of 14%, had a HR of 1.68 (95% CI=1.13-2.50; P=0.011). Significant alteration in circulating androsterone levels was associated with this haplotype, consistent with changes in hormonal exposure. This study provides the first evidence, to our knowledge, that germline polymorphisms of UGT1 are potential predictors of recurrence of PCa after prostatectomy.

Multiple roles for UDP-glucuronosyltransferase (UGT)2B15 and UGT2B17 enzymes in androgen metabolism and prostate cancer evolution

In the prostate, approximately 50% of androgens are from adrenal steroids, mainly dehydroepiandrosterone (DHEA), its sulfate and androstenedione. These compounds are converted first into testosterone, and then into the active hormone dihydrotestosterone (DHT). After having activated the androgen receptor (AR), DHT is reduced into androstane-3α-DIOL (3α-DIOL) and androsterone (ADT), which are subsequently converted into 2 inactive and easily excretable metabolites: 3α-DIOL-17glucuronide (3α-DIOL-17G) and ADT-3glucuronide (ADT-3G). The formation of these last derivatives through the glucuronidation reaction involves 2 UDP-glucuronosyltransferase (UGT) enzymes, namely UGT2B15 and UGT2B17. The present review article aims at providing a comprehensive view of the physiological and pharmacological importance of these 2 enzymes for the control of androgen homeostasis. We will resume: (i) how UGT2B15 and UGT2B17 contribute to androgen elimination; (ii) how their glucuronidation capacity influences the androgen signaling pathway in prostate cells; (iii) how they contribute to the anti-proliferative properties of AR antagonists in prostate cancer cells; and (iv) how AR and its spliced variants regulate the UGT2B15 and/or UGT2B17 genes expression. Finally, whether the unexploited AR-UGT axis could serve as a prognostic maker or a pharmacological target for novel therapeutics in the treatment of prostate cancer is also discussed. This article is part of a special issue entitled 'Essential role of DHEA'.

Androgen biosynthesis in castration-resistant prostate cancer

Prostate cancer is the second leading cause of death in adult males in the USA. Recent advances have revealed that the fatal form of this cancer, known as castration-resistant prostate cancer (CRPC), remains hormonally driven despite castrate levels of circulating androgens. CRPC arises as the tumor undergoes adaptation to low levels of androgens by either synthesizing its own androgens (intratumoral androgens) or altering the androgen receptor (AR). This article reviews the major routes to testosterone and dihydrotestosterone synthesis in CRPC cells and examines the enzyme targets and progress in the development of isoform-specific inhibitors that could block intratumoral androgen biosynthesis. Because redundancy exists in these pathways, it is likely that inhibition of a single pathway will lead to upregulation of another so that drug resistance would be anticipated. Drugs that target multiple pathways or bifunctional agents that block intratumoral androgen biosynthesis and antagonize the AR offer the most promise. Optimal use of enzyme inhibitors or AR antagonists to ensure maximal benefits to CRPC patients will also require application of precision molecular medicine to determine whether a tumor in a particular patient will be responsive to these treatments either alone or in combination.

Pharmacogenomics of human uridine diphospho-glucuronosyltransferases and clinical implications

Glucuronidation by uridine diphospho-glucuronosyltransferase enzymes (UGTs) is a major phase II biotransformation pathway and, complementary to phase I metabolism and membrane transport, one of the most important cellular defense mechanisms responsible for the inactivation of therapeutic drugs, other xenobiotics, and endogenous molecules. Interindividual variability in UGT pathways is significant and may have profound pharmacological and toxicological implications. Several genetic and genomic processes underlie this variability and are discussed in relation to drug metabolism and diseases such as cancer.

Genetic variants in microRNAs and microRNA target sites predict biochemical recurrence after radical prostatectomy in localized prostate cancer

Recent evidence indicates that microRNAs might participate in prostate cancer initiation, progression and treatment response. Germline variations in microRNAs might alter target gene expression and modify the efficacy of prostate cancer therapy. To determine whether genetic variants in microRNAs and microRNA target sites are associated with the risk of biochemical recurrence (BCR) after radical prostatectomy (RP). We retrospectively studied two independent cohorts composed of 320 Asian and 526 Caucasian men with pathologically organ-confined prostate cancer who had a median follow-up of 54.7 and 88.8 months after RP, respectively. Patients were systematically genotyped for 64 single-nucleotide polymorphisms (SNPs) in microRNAs and microRNA target sites, and their prognostic significance on BCR was assessed by Kaplan-Meier analysis and Cox regression model. After adjusting for known clinicopathologic risk factors, two SNPs (MIR605 rs2043556 and CDON rs3737336) remained associated with BCR. The numbers of risk alleles showed a cumulative effect on BCR [perallele hazard ratio (HR) 1.60, 95% confidence interval (CI) 1.16-2.21, p for trend = 0.005] in Asian cohort, and the risk was replicated in Caucasian cohort (HR 1.55, 95% CI 1.15-2.08, p for trend = 0.004) and in combined analysis (HR 1.57, 95% CI 1.26-1.96, p for trend <0.001). Results warrant replication in larger cohorts. This is the first study demonstrating that SNPs in microRNAs and microRNA target sites can be predictive biomarkers for BCR after RP.

Importance of 5α-reductase gene polymorphisms on circulating and intraprostatic androgens in prostate cancer

PURPOSE

Polymorphisms in the genes SRD5A1 and SRD5A2 encoding androgen biosynthetic 5α-reductase enzymes have been associated with an altered risk of biochemical recurrence after radical prostatectomy in localized prostate cancer.

EXPERIMENTAL DESIGN

To gain potential insights into SRD5A biologic effects, we examined the relationship between SRD5A prognostic markers and endogenous sex-steroid levels measured by mass spectrometry in plasma samples and corresponding prostatic tissues of patients with prostate cancer.

RESULTS

We report that five of the seven SRD5A markers differentially affect sex-steroid profiles of dihydrotestosterone and its metabolites in both the circulation and prostatic tissues of patients with prostate cancer. Remarkably, a 32% increase in intraprostatic testosterone levels was observed in the presence of the high-risk SRD5A rs2208532 polymorphism. Moreover, SRD5A2 markers were associated predominantly with circulating levels of inactive glucuronides. Indeed, the rs12470143 SRD5A2 protective allele was associated with high circulating androstane-3α, 17β-diol-17-glucuronide (3α-diol-17G) levels as opposed to lower levels of both 3α-diol-17G and androsterone-glucuronide observed with the rs2208532 SRD5A2 risk allele. Moreover, SRD5A2 rs676033 and rs523349 (V89L) risk variants, in strong linkage disequilibrium, were associated with higher circulating levels of 3α-diol-3G. The SRD5A2 rs676033 variant further correlated with enhanced intraprostatic exposure to 5α-reduced steroids (dihydrotestosterone and its metabolite 3β-diol). Similarly, the SRD5A1 rs166050C risk variant was associated with greater prostatic exposure to androsterone, whereas no association was noted with circulating steroids.

CONCLUSIONS

Our data support the association of 5α-reductase germline polymorphisms with the hormonal milieu in patients with prostate cancer. Further studies are needed to evaluate if these variants influence 5α-reductase inhibitor efficacy.

UGT2B17 Polymorphism and Risk of Prostate Cancer: A Meta-Analysis

Objective. Recent studies on the association between uridine diphosphosglucuronosyltransferases (UGTs) 2B17 polymorphism and risk of prostate cancer (PCa) showed inconclusive results. To clarify this possible association, we conducted a meta-analysis of published studies. Methods. We searched the published literature from PubMed, Embase, Google Scholar, and China National Knowledge Infrastructure (CNKI). According to our inclusion criteria, studies that observed the association between UGT2B17 polymorphism and PCa risk were included. The principal outcome measure was the adjusted odds ratio (OR) with 95% confidence interval (CI) for the risk of PCa associated with UGT2B17 polymorphism. Results. A total of 6 studies with 7,029 subjects (3,839 cases and 3,190 controls) were eligible for inclusion in the meta-analysis. Overall, there was a significant association between UGT2B17 polymorphism and increased risk of prostate cancer (OR = 1.74, 95% CI 1.14-2.64, P < 0.001). Similar results were found in the subgroup analyses by ethnicity and types of controls. Conclusion. This meta-analysis demonstrates that UGT2B17 polymorphism is associated with prostate cancer susceptibility, and it contributes to the increased risk of prostate cancer.

Phase two steroid metabolism and its roles in breast and prostate cancer patients

Breast and prostate cancer are diseases in which steroids and steroid metabolism could markedly influence clinical outcomes for patients. In both malignancies the modification of ketone and hydroxyl groups attached to the steroid backbone (phase one metabolism) has been examined in detail but the conjugation reactions (phase two metabolism) have not been extensively studied. Therefore, in this review we aim to summarize phase two metabolism in breast and prostate cancers from a number of perspectives, including the impact of variation in serum levels of conjugated steroids, tissue, and pathology specific expression of phase two enzymes, and consequences of genetic variations of these conjugation enzymes. In addition to this biological perspective, we will also address current pharmacological efforts to manipulate phase two metabolism as a potential therapy for hormone dependent cancers, including clinical trials of STS inhibitors and preclinical STS inhibitor development. While this review is not intended to cover any one particular area in great technical depth, it is intended as an introduction to and/or update on the importance of variance in phase two metabolic pathways in breast and prostate cancers.

Nuclear receptors and endobiotics glucuronidation: the good, the bad, and the UGT

The recent progresses in molecular biology and pharmacology approaches allowed the characterization of a series of nuclear receptors (NRs) as efficient regulators of uridine diphosphate glucuronosyltransferase (UGT) genes activity. These regulatory processes ensure an optimized UGT expression in response to specific endo- and/or exogenous stimuli. Many of these NRs are activated by endobiotics that also are substrates for UGTs. Thus, by activating their receptors, these endogenous substances control their own conjugation, leading to the concept that glucuronidation is an important part of feed-forward/feedback mechanisms by which bioactive molecules control their own concentrations. On the other hand, numerous studies have established the pharmacological relevance of NR-UGT regulatory pathways in the response to therapeutic ligands. The present review article aims at providing a comprehensive view of the physiological and pharmacological importance of the NR regulation of the expression and activity of endobiotics-conjugating UGT enzymes. Selected examples will illustrate how the organism profits from the feed-forward/feedback mechanisms involving NR-UGT pathways, but also how such regulatory processes are involved in the initiation and/or progression of several pathological situations. Finally, we will discuss how the present pharmacopeia involves NR-dependent regulation of endobiotics glucuronidation, and whether the unexploited NR-UGT axes could serve as pharmacological targets for novel therapeutics to restore endobiotics homeostasis.

UDP-glucuronosyltransferase 2B17 genotype and the risk of lung cancer among Austrian Caucasians

BACKGROUND

The enzyme uridine diphospho glucuronosyltansferase 2B17 (UGT2B17) glucuronidates several endogenous and exogenous compounds, including carcinogens from tobacco smoke like 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanl (NNAL). UGT2B17 shows a remarkable copy number variation (CNV) and an association between deletion genotype and increased risk of lung adenocarcinoma in women has been previously reported.

METHODS

We investigated the UGT2B17 CNV by PCR in 453 Austrian lung cancer patients and in 449 healthy donors and analyzed the impact on lung cancer susceptibility and outcome.

RESULTS

Copy numbers of UGT2B17 were 44.4% (+/+), 42.2% (+/-) and 13.5% (-/-) in lung cancer patients and 43.0% (+/+), 46.3% (+/-) and 10.7% (-/-) among healthy donors. The null genotype was not significantly more frequent among women with adenocarcinoma compared to healthy women (p=0.59). There was no association with overall survival (p=0.622) and no significant sex-associated (p=0.423) or histology-related impact on development of lung cancer.

CONCLUSION

UGT2B17 deletion genotype was not associated with a significant risk for lung cancer development or outcome in our Central European patient cohort. Our study indicates that UGT2B17 is not a crucial factor in lung carcinogenesis among Caucasians and shows the importance of investigating such markers in large cohorts from different populations.

The effect of copy number variation in the phase II detoxification genes UGT2B17 and UGT2B28 on colorectal cancer risk

BACKGROUND

Genetic polymorphisms in combination with the Western-style diet, physical inactivity, smoking, excessive alcohol consumption, and obesity have been hypothesized to affect colorectal cancer (CRC) risk. Metabolizers of environmental carcinogenic and endogenous compounds affecting CRC risk include the phase II detoxification UDP-glucuronosyltransferase (UGT) enzymes UGT2B17 and UGT2B28, which are 2 of the most commonly deleted genes in the genome.

METHODS

To study the effect of UGT2B17 and UGT2B28 copy number variation (CNV) on CRC risk, 665 Caucasian CRC cases and 621 Caucasian controls were genotyped who had completed extensive demographics and lifestyle questionnaires.

RESULTS

A significant association between the UGT2B17 deletion genotype (0/0) and decreased CRC risk was found when the entire population was analyzed (P = .044). Stratification by sex yielded a decreased risk (P = .020) in men with the UGT2B17 deletion (0/0), but no association was observed in women (P = .724). A significant association between UGT2B17 (0/0) and decreased risk for rectal (P = .0065) but not colon cancer was found. No significant association was found between UGT2B28 CNV and CRC risk.

CONCLUSIONS

The UGT2B17 deletion genotype (0/0) was associated with a decreased CRC risk in a Caucasian population. After sex stratification, the association was observed in men but not in women, which is consistent with previous findings that men have higher UGT2B17 expression and activity than women. Because UGT2B17 metabolizes certain nonsteroidal anti-inflammatory drugs and flavonoids with antioxidative properties, individuals with a gene deletion may have higher levels of these protective dietary components.

Overexpression of uridine diphospho glucuronosyltransferase 2B17 in high-risk chronic lymphocytic leukemia

Uridine diphospho glucuronosyltransferase 2B17 (UGT2B17) is overexpressed in poor prognostic chronic lymphocytic leukemia.

Molecular markers in key steroidogenic pathways, circulating steroid levels, and prostate cancer progression

PURPOSE

Prostate cancer is a heterogeneous genetic disease, and molecular methods for predicting prognosis in patients with aggressive form of the disease are urgently needed to better personalize treatment approaches. The objective was to identify host genetic variations in candidate steroidogenic genes affecting hormone levels and prostate cancer progression.

EXPERIMENTAL DESIGN

The study examined two independent cohorts composed of 526 Caucasian men with organ-confined prostate cancer and 601 Taiwanese men on androgen-deprivation therapy. Caucasians were genotyped for 109 haplotype-tagging single-nucleotide polymorphisms (SNP) in CYP17A1, ESR1, CYP19A1, and HSD3B1, and their prognostic significance on disease progression was assessed using Kaplan-Meier survival curves and Cox regression models. Positive findings, including previously identified SRD5A1, SRD5A2, HSD17B2, HSD17B3, and HSD17B12 polymorphisms, were then explored in Taiwanese men (n = 32 SNPs). The influence of positive markers on the circulating hormonal levels was then appraised in Caucasians using specific and sensitive mass spectrometry-based methods.

RESULTS

After adjusting for known risk factors, variants of CYP17A1 (rs6162), HSD17B2 (rs4243229 and rs7201637), and ESR1 (rs1062577) were associated with progressive disease in both cohorts. Indeed, the presence of these variations was significantly associated with progression in Caucasians (HR, 2.29-4.10; P = 0.0014-2 × 10(-7)) and survival in Taiwanese patients [HR = 3.74; 95% confidence interval (CI): 1.71-8.19, P = 0.009]. Remarkably, the CYP17A1 rs6162 polymorphism was linked to plasma dehydroepiandrosterone-sulfate (DHEA-S) levels (P = 0.03), HSD17B2 rs7201637 with levels of dihydrotestosterone (P = 0.03), and ESR1 rs1062577 with levels of estrone-S and androsterone-glucuronide (P ≤ 0.05).

CONCLUSION

This study identifies, in different ethnic groups and at different disease stages, CYP17A1, HSD17B2, and ESR1 as attractive prognostic molecular markers of prostate cancer progression.

Association of uridine diphosphate-glucuronosyltransferase 2B gene variants with serum glucuronide levels and prostate cancer risk

AIMS

Uridine diphosphate-glucuronosyltransferase 2B (UGT2B) enzymes conjugate testosterone metabolites to enable their excretion in humans. The functional significance of the UGT2B genetic variants has never been described in humans. We evaluated UGT2B variants in relation to plasma androstane-3α,17β-diol-glucuronide (AAG) levels and the prostate cancer risk.

RESULTS

AAG levels were measured in sera from 150 controls and compared to the polymorphisms of UGT2B17, UGT2B15, and UGT2B7. Genomic DNA from controls (301) and cases (148) was genotyped for the polymorphisms, and odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated using unconditional logistic regression analyses. Having two copies of UGT2B17 was associated with higher AAG levels in controls among Whites (p=0.02), but not Blacks (p=0.82). Logistic regression models adjusting for age and race revealed that homozygosity for the G allele of the UGT2B15(D85Y) polymorphism was directly associated with the prostate cancer risk (OR=2.70, 95% CI=1.28, 5.55).

CONCLUSIONS

While the small sample size limits inference, our findings suggest that an association between the UGT2B17 copy number variant (CNV) and serum AAG levels in Whites, but unexpectedly not in Blacks. This novel observation suggests that genetic determinants of AAG levels in Blacks are unrelated to the UGT2B17 CNV. This study replicates the results that show an association of UGT215(D85Y) with an increased prostate cancer risk.