ABSTRACT: Cytochrome P450 17alpha-hydroxylases-C-(17,20)-lyase (CYP17) is a key enzyme involved with the androgen biosynthesis pathway and has recently been targeted for therapy in men with advanced prostate cancer (PCa). However, studies relating prostate cancer outcomes with CYP17 gene variants have conflicting results. In this study we analyzed Single Nucleotide Polymorphisms (SNPs) spanning the CYP17 gene for association with PCa survival.The cohort was comprised of Caucasian men, aged 40-64, diagnosed with PCa between 1993 and 1996 in King County, Washington who participated in a population-based case-control study. CYP17 SNPs were selected to capture variation across the gene and known regulatory regions. PCa-specific mortality (PCSM) was obtained by linking to the SEER cancer registry. Recurrence/progression of PCa was determined from patient survey data and medical records. Cox proportional hazards regression analysis was used to generate hazard ratios for patient outcomes.Genotypes were available for 598 cases. With a median follow-up of 13.2 years, 44 PCa deaths were observed. Recurrence/progression events were observed in 30% of subjects. No genetic association with disease progression were identified. However, men with the variant A allele in rs10883783 had a 56% risk reduction in PCSM (HR 0.44, 95% CI 0.21-0.98).These data suggest that genetic variation in the CYP17 gene in Caucasian men is associated with PCa survival.
Project description:Since androgen signaling plays a pivotal role in the proliferation and metastasis of prostate cancer, androgen deprivation therapy (ADT) or castration therapy is considered the backbone of treatment for newly diagnosed metastatic prostate cancer. However, almost all men experience disease progression on ADT to a state known as metastatic castration-resistant prostate cancer (mCRPC), which continues to be driven by intratumoral androgen synthesis or androgen receptor signaling. Hence, the extragonadal ablation of androgen synthesis from pregnane precursors holds much promise. An inhibitor of cytochrome P450 17?-hydroxy/17,20-lyase (CYP17) enzymes, abiraterone acetate, has already been approved for men with mCRPC. Newer CYP17 inhibitors continue to be developed which are either more selective or have concomitant inhibitory actions on AR signaling. These include VT-464, orteronel, and galeterone. Herein, we focus on the molecular mechanism of action, efficacy, latest evidence, and clinical potential of CYP17 inhibitors in prostate cancer.
Project description:Prostate cancer (PC) is now the second most prevalent cause of death in men in the USA and Europe. At present, the major treatment options include surgical or medical castration. These strategies cause ablation of the production of testosterone (T), dihydrotestosterone (DHT) and related androgens by the testes. However, because these procedures do not affect adrenal, prostate and other tissues' androgen production, they are often combined with androgen receptor antagonists to block their action. Indeed, recent studies have unequivocally established that in castration-resistant prostate cancer (CRPC) many androgen-regulated genes become re-expressed and tissue androgen levels increase despite low serum levels. Clearly, inhibition of the key enzyme which catalyzes the biosynthesis of androgens from pregnane precursors, 17?-hydroxy/17,20-lyase (hereafter referred to as CYP17) could prevent androgen production from all sources. Thus, total ablation of androgen production by potent CYP17 inhibitors may provide effective treatment of prostate cancer patients. This review highlights the role of androgen biosynthesis in the progression of prostate cancer and the impact of CYP17 inhibitors, such as ketoconazole, abiraterone acetate, VN/124-1 (TOK-001) and TAK-700 in the clinic and in clinical development. Article from the special issue on Targeted Inhibitors.
Project description:BACKGROUND:A meta and pooled analysis of published and unpublished case-control studies was performed to evaluate the association of CYP17 (rs743572) and CYP3A4 (rs2740574) polymorphisms and prostate cancer (PCa) in men from the USA, Caribbean, and Africa. METHODS:Eight publications (seven studies) and two unpublished studies for CYP17 included 1,580 subjects (559 cases and 1,021 controls) and eleven publications and three unpublished studies for CYP3A4 included 3,400 subjects (1,429 cases and 1,971 controls). RESULTS:Overall, the CYP17 heterozygous and homozygous variants were not associated with PCa, but they confer a 60% increased risk of PCa in a sub-group analysis restricted to African-American men (T/C?+?C/C, OR: 1.6, 95% CI: 1.1-2.4). No associations were observed for CYP3A4, overall and in stratified analyses for African-Americans and Africans. The pooled analysis suggests that after adjusting for study, age, PSA, and family history of PCa, CYP17 was associated with PCa for men of African ancestry (Adjusted OR: 3.5, 95% CI: 1.2-10.0). CONCLUSIONS:Our findings suggest that genetic factors involved in the androgen pathway play a role in PCa risk among men of African ancestry.
Project description:The natural history of prostate-specific antigen (PSA)-defined biochemical recurrence (BCR) of prostate cancer (PCa) after definitive local therapy is highly variable. Validated prediction models for PCa-specific mortality (PCSM) in this population are needed for treatment decision-making and clinical trial design.To develop and validate a nomogram to predict the probability of PCSM from the time of BCR among men with rising PSA levels after radical prostatectomy.Between 1987 and 2011, 2254 men treated by radical prostatectomy at one of five high-volume hospitals experienced BCR, defined as three successive PSA rises (final value >0.2 ng/ml), single PSA >0.4 ng/ml, or use of secondary therapy administered for detectable PSA >0.1 ng/ml. Clinical information and follow-up data were modeled using competing-risk regression analysis to predict PCSM from the time of BCR.Radical prostatectomy for localized prostate cancer and subsequent PCa BCR.PCSM.The 10-yr PCSM and mortality from competing causes was 19% (95% confidence interval [CI] 16-21%) and 17% (95% CI 14-19%), respectively. A nomogram predicting PCSM for all patients had an internally validated concordance index of 0.774. Inclusion of PSA doubling time (PSADT) in a nomogram based on standard parameters modestly improved predictive accuracy (concordance index 0.763 vs 0.754). Significant parameters in the models were preoperative PSA, pathological Gleason score, extraprostatic extension, seminal vesicle invasion, time to PCa BCR, PSA level at PCa BCR, and PSADT (all p<0.05).We constructed and validated a nomogram to predict the risk of PCSM at 10 yr among men with PCa BCR after radical prostatectomy. The nomogram may be used for patient counseling and the design of clinical trials for PCa.For men with biochemical recurrence of prostate cancer after radical prostatectomy, we have developed a model to predict the long-term risk of death from prostate cancer.
Project description:The enzyme CYP17 primarily regulates androgen production by mediating four reactions: conversion of pregnenolone and progesterone to 17-hydroxypregnenolone and 17-hydroxyprogesterone, respectively (17alpha-hydroxylase activity), followed by conversion of the 17-hydroxylated steroids to dehydroepiandrosterone and androstenedione, respectively (17,20-lyase activity). Most mammalian CYP17 isoforms have high 17alpha-hydroxylase relative to 17,20-lyase activities and preferentially mediate one of the two 17,20-lyase reactions. In contrast, Xenopus laevis CYP17 potently regulates all four reactions in the frog ovary. CYP17 isoforms generally rely on the cofactor cytochrome b(5) for the 17,20-lyase reaction, suggesting that the high lyase activity of Xenopus CYP17 might be due to a lesser dependence on b(5). The kinetics of Xenopus CYP17 expressed in yeast microsomes were therefore examined in the absence and presence of Xenopus on human b(5). Xenopus CYP17 mediated both 17,20-lyase reactions in the absence of b(5), confirming that the activity did not require b(5). However, both Xenopus and human b(5) slightly enhanced Xenopus CYP17-mediated lyase activity, indicating that the enzyme was still at least partially responsive to b(5). Surprisingly, only the human b(5) cofactor enhanced human CYP17-mediated lyase activity, implying that the human enzyme had more specific cofactor requirements than Xenopus CYP17. Studies using human/Xenopus chimeric b(5) proteins revealed that human b(5) residues 16-41 were important for the specific regulation of the lyase activity of HuCYP17, possibly serving as an interacting domain with the enzyme. CYP17 may therefore have evolved from a general producer of sex steroids in lower vertebrates to a more tightly regulated producer of both sex steroids and glucocorticoids in mammals.
Project description:<h4>Objectives</h4>To perform a comparison and external validation of three models predicting biochemical recurrence (BCR) and three models predicting prostate cancer (PCa)-specific mortality (PCSM) in a screening setting, i.e. patients with screening-detected PCa (S-PCa) and in those with clinically detected PCa (C-PCa).<h4>Subjects and methods</h4>We retrospectively evaluated 795 men with S-PCa, from the European Randomized Study of Screening for Prostate Cancer, Rotterdam, and 1123 men with C-PCa initially treated with RP. The discriminative ability of the models was assessed according to the area under the curve (AUC) of the receiver-operating characteristic, and calibration was assessed graphically using calibration plots.<h4>Results</h4>The median (interquartile range [IQR]) follow-up for the S-PCa group was 10.4 (6.8-14.3) years and for the C-PCa group it was 8.8 (4.8-12.9) years. A total of 123 men with S-PCa (15%) and 389 men with C-PCa (35%) experienced BCR. Of the men with S-PCa and BCR, 24 (20%) died from PCa and 29 (23%) died from other causes. Of the men with C-PCa and BCR, 68 (17%) died from PCa and 105 (27%) died from other causes. The discrimination of the models predicting BCR or PCSM was higher for men with S-PCa (AUC: BCR 0.77-0.84, PCSM 0.60-0.77) than for the men with C-PCa (AUC: BCR 0.75-0.79, PCSM 0.51-0.68) as a result of the similar patient characteristics of the men with S-PCa in the present study and those of the cohorts used to develop these models. The risk of BCR was typically overestimated, while the risk of PCSM was typically underestimated.<h4>Conclusion</h4>Prediction models for BCR showed good discrimination and reasonable calibration for both men with S-PCa and men with C-PCa, and even better discrimination for men with S-PCa. For PCSM, the evaluated models are not applicable in both settings of this Dutch cohort as a result of substantial miscalibration. This warrants caution when using these models to communicate future risks in other clinical settings.
Project description:Metastases from men with castration-resistant prostate cancer (CRPC) harbor increased tumoral androgens versus untreated prostate cancers. This may reflect steroid uptake by OATP (organic anion transporting polypeptide)/SLCO transporters. We evaluated SLCO gene expression in CRPC metastases and determined whether prostate cancer outcomes are associated with single nucleotide polymorphisms (SNP) in SLCO2B1 and SLCO1B3, transporters previously shown to mediate androgen uptake.Transcripts encoding eleven SLCO genes were analyzed in untreated prostate cancer and in metastatic CRPC tumors obtained by rapid autopsy. SNPs in SLCO2B1 and SLCO1B3 were genotyped in a population-based cohort of 1,309 Caucasian prostate cancer patients. Median survival follow-up was 7.0 years (0.77-16.4). The risk of prostate cancer recurrence/progression and prostate cancer-specific mortality (PCSM) was estimated with Cox proportional hazards analysis.Six SLCO genes were highly expressed in CRPC metastases versus untreated prostate cancer, including SLCO1B3 (3.6-fold; P = 0.0517) and SLCO2B1 (5.5-fold; P = 0.0034). Carriers of the variant alleles SLCO2B1 SNP rs12422149 (HR: 1.99; 95% CI: 1.11-3.55) or SLCO1B3 SNP rs4149117 (HR: 1.76; 95% CI: 1.00-3.08) had an increased risk of PCSM.CRPC metastases show increased expression of SLCO genes versus primary prostate cancer. Genetic variants of SLCO1B3 and SLCO2B1 are associated with PCSM. Expression and genetic variation of SLCO genes which alter androgen uptake may be important in prostate cancer outcomes.OATP/SLCO genes may be potential biomarkers for assessing risk of PCSM. Expression and genetic variation in these genes may allow stratification of patients to more aggressive hormonal therapy or earlier incorporation of nonhormonal-based treatment strategies.
Project description:Few studies focus on prostate cancer (PCa) outcomes in Hispanic/Latino men. Our study explores whether Hispanic/Latino subgroups demonstrate significantly different prostate cancer-specific mortality (PCSM) relative to Non-Hispanic White (NHW) and Non-Hispanic Black (NHB) men.We extracted a population-based cohort of men diagnosed with local-regional PCa from 2000-2013 (n= 486,865). PCSM was measured in racial/ethnic groups: NHW (n=352,886), NHB (n= 70,983), Hispanic/Latino (n= 40,462), and Asian American/Pacific Islander (n= 22,534). PCSM was also measured in Hispanic/Latino subgroups: Mexican (n= 8,077), Puerto Rican (n= 1,284), South or Central American (n= 3,021), Cuban (n= 788), and Dominican (n= 300). We conducted univariable and multivariable analyses (MVA) to compare risk for PCSM.Compared to NHW men, results showed worse outcomes for NHB men with similar outcomes for Hispanic/Latino men. In MVA with NHW men as a reference, NHB (HR= 1.15, p <0.001) men had significantly worse PCSM and Hispanic/Latino (HR= 1.02, p= 0.534) men did not show a significant difference. In a second MVA, Puerto Rican (HR= 1.71, p <0.001) and Mexican (HR= 1.21, p= 0.008) men had significantly higher PCSM. With NHB men as a reference, the MVA showed Puerto Rican (HR= 1.50, p= 0.006) men with higher PCSM and Mexican (HR= 1.08, p= 0.307) men with no significant difference.Our findings indicate previously unknown disparities in PCSM for Puerto Rican and Mexican American men.
Project description:Association studies have examined the significance of several candidate genes based on biological pathways relevant to prostate carcinogenesis, including both the androgen and insulin-like growth factor pathways. Clinical and epidemiologic evidence suggest that androgens, specifically testosterone and dihydrotestosterone (DHT) are important not only in normal prostate growth but in the pathogenesis of prostate cancer. Similarly, the insulin-like growth factor-1 (IGF-1) signaling pathway regulates both cellular proliferation and apoptosis. Therefore, genes involved in the biosynthesis, activation, metabolism and degradation of androgens and the stimulation of mitogenic and antiapoptotic activities of prostate epithelial cells represent important candidates for affecting the development and progression of prostate cancer.Using resources from the Flint Men's Health Study, a population-based case control study of African-American men aged 40-79, we evaluated the associations between selected single-nucleotide polymorphisms (SNPs) in the CYP17, CYP3A4, CYP19A1, SDR5A2, IGF1, and IGFBP3 genes and prostate cancer diagnosis in 473 men (131 prostate cancer cases and 342 disease-free controls).We found a significant association between prostate cancer and selected CYP17 SNP genotypes, with the heterozygous genotype conferring decreased risk. Suggestive evidence for association between IGF1 SNPs and prostate cancer were also found. No significant associations were observed between SNPs in the other genes and prostate cancer.These findings suggest that variation in or around CYP17 and/or IGF1 may be associated with prostate cancer development in the African-American population. Additional studies are needed to determine whether these polymorphisms are indeed associated with prostate cancer risk in African Americans.
Project description:ERG and androgen receptor (AR) are known to function cooperatively in prostate cancer (PCa) progression. However, the prognostic value of combined ERG and AR expression and potential pathways are not well characterized. We assessed ERG and AR protein expression by immunohistochemistry in a cohort of 312 men with PCa diagnosed by transurethral resection of the prostate (TURP). Patients were divided into those with no prior hormonal treatment (designated as PCa/AdvPCa) vs. those with castrate-resistant PCa (CRPC) undergoing channel TURP to relieve obstructive symptoms. The expression status was correlated with various clinical-pathological parameters. The Swedish watchful-waiting cohort was used for validation and characterization of potential gene signatures associated with ERG and AR. Patients with combined ERG-positive/AR high expression profile demonstrated higher rates of PCa-specific mortality (PCSM) compared with patients with ERG-negative/AR low in patients with no prior treatment (n = 90, P = 0.032), but this was attenuated in the overall cohort which included the CRPC subgroup (n = 125, P = 0.096). The prognostic significance to PCSM was validated in the Swedish watchful waiting cohort in univariate (HR: 3.3; 95% CI: 1.9-5.6, P = 4.25E-5) and multivariate analysis (HR: 2; 95% CI: 0.97-4.1, P = 0.057), which included Gleason score. ERG/AR overexpression status characterized 152 genes signatures including WNT, PI3K/AKT and chemokine signaling pathways known to be deregulated in PCa. In conclusion, combined ERG/AR overexpression signifies a class of patients at highest-risk of PCSM with specific key genetic alteration likely responsible for disease progression. The prognostic value of combined ERG/AR overexpression and its associated genes should be further investigated as potential prognostic and therapeutic targets in prostate cancer progression.