SRD5A gene polymorphism in Japanese men predicts prognosis of metastatic prostate cancer with androgen-deprivation therapy

Sex hormone-binding globulin and its critical role in prostate cancer: A comprehensive review

Prostate cancer (PC) is a common and widespread cancer that affects men globally. A complicated interaction of hormonal variables influences its development. Sex hormone-binding globulin (SHBG) is a crucial element in controlling the availability of sex hormones, especially androgens, which have a notable impact on the development and progression of PC. SHBG controls the levels of free, active androgens in the body, which helps regulate androgen-dependent processes associated with PC. The equilibrium between SHBG and androgens plays a critical role in maintaining the stability of the prostate. When this balance is disrupted, it is associated with the development and advancement of PC. The processes responsible for SHBG's role in PC are complex and have multiple aspects. SHBG primarily binds to androgens, preventing them from interacting with androgen receptors (ARs) in prostate cells. It reduces the activation of androgen signaling pathways essential for tumor development and survival. In addition, SHBG can directly affect prostate cells by interacting with specific receptors on the cell surface. This review thoroughly examines the role of SHBG in PC, including its physiological activities, methods of action, and clinical consequences.

Genome-wide association study of blood lipid levels in Southern Han Chinese adults with prediabetes

Background

Dyslipidemia is highly prevalent among individuals with prediabetes, further exacerbating their cardiovascular risk. However, the genetic determinants underlying diabetic dyslipidemia in Southern Han Chinese remain largely unexplored.

Methods

We performed a genome-wide association study (GWAS) of blood lipid traits in 451 Southern Han Chinese adults with prediabetes. Fasting plasma lipids, including triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) were assayed. Genotyping was conducted using the Precision Medicine Diversity Array and Gene Titan platform, followed by genotype imputation using IMPUTE2 with the 1000 Genomes Project (Phase 3, Southern Han Chinese) as reference. Single nucleotide polymorphisms (SNPs) associated with lipid levels were identified using mixed linear regression, with adjustment for covariates.

Results

We identified 58, 215, 74 and 81 novel SNPs associated with TG, TC, HDL-C and LDL-C levels, respectively (P < 5×10-5). Several implicated loci were located in or near genes involved in lipid metabolism, including SRD5A2, PCSK7, PITPNC1, IRX3, BPI, and LBP. Pathway enrichment analysis highlighted lipid metabolism and insulin secretion.

Conclusion

This first GWAS of dyslipidemia in Southern Han Chinese with prediabetes identified novel genetic variants associated with lipid traits. Our findings provide new insights into genetic mechanisms underlying heightened cardiovascular risk in the prediabetic stage. Functional characterization of implicated loci is warranted.

Enhancing Metabolome Annotation by Electron Impact Excitation of Ions from Organics-Molecular Networking

Liquid chromatography-high-resolution mass spectrometry (LC-HRMS) is widely used in untargeted metabolomics, but large-scale and high-accuracy metabolite annotation remains a challenge due to the complex nature of biological samples. Recently introduced electron impact excitation of ions from organics (EIEIO) fragmentation can generate information-rich fragment ions. However, effective utilization of EIEIO tandem mass spectrometry (MS/MS) is hindered by the lack of reference spectral databases. Molecular networking (MN) shows great promise in large-scale metabolome annotation, but enhancing the correlation between spectral and structural similarity is essential to fully exploring the benefits of MN annotation. In this study, a novel approach was proposed to enhance metabolite annotation in untargeted metabolomics using EIEIO and MN. MS/MS spectra were acquired in EIEIO and collision-induced dissociation (CID) modes for over 400 reference metabolites. The study revealed a stronger correlation between the EIEIO spectra and metabolite structure. Moreover, the EIEIO spectral network outperformed the CID spectral network in capturing structural analogues. The annotation performance of the structural similarity network for untargeted LC-MS/MS was evaluated. For the spiked NIST SRM 1950 human plasma, the annotation coverage and accuracy were 72.94 and 74.19%, respectively. A total of 2337 metabolite features were successfully annotated in NIST SRM 1950 human plasma, which was twice that of LC-CID MS/MS. Finally, the developed method was applied to investigate prostate cancer. A total of 87 significantly differential metabolites were annotated. This study combining EIEIO and MN makes a valuable contribution to improving metabolome annotation.

Analysis of genetic biomarkers, polymorphisms in ADME-related genes and their impact on pharmacotherapy for prostate cancer

Prostate cancer (PCa) is a non-cutaneous malignancy in males with wide variation in incidence rates across the globe. It is the second most reported cause of cancer death. Its etiology may have been linked to genetic polymorphisms, which are not only dominating cause of malignancy casualties but also exerts significant effects on pharmacotherapy outcomes. Although many therapeutic options are available, but suitable candidates identified by useful biomarkers can exhibit maximum therapeutic efficacy. The single-nucleotide polymorphisms (SNPs) reported in androgen receptor signaling genes influence the effectiveness of androgen receptor pathway inhibitors and androgen deprivation therapy. Furthermore, SNPs located in genes involved in transport, drug metabolism, and efflux pumps also influence the efficacy of pharmacotherapy. Hence, SNPs biomarkers provide the basis for individualized pharmacotherapy. The pharmacotherapeutic options for PCa include hormonal therapy, chemotherapy (Docetaxel, Mitoxantrone, Cabazitaxel, and Estramustine, etc.), and radiotherapy. Here, we overview the impact of SNPs reported in various genes on the pharmacotherapy for PCa and evaluate current genetic biomarkers with an emphasis on early diagnosis and individualized treatment strategy in PCa.

A Phase II Trial of Abiraterone With Dutasteride for Second-Generation Antiandrogen- and Chemotherapy-Naïve Patients With Castration-Resistant Prostate Cancer

The development of a novel therapy to overcome primary and acquired resistance to abiraterone is an unmet need. This study aimed to evaluate the efficacy and safety of adding 5α-reductase inhibitor dutasteride to abiraterone, explore proof of concept, and identify candidates suitable for combination therapy. This phase II, single-arm, and open-label study enrolled second-generation antiandrogen- and chemotherapy-naïve patients with castration-resistant prostate cancer. Patients received abiraterone and prednisolone for 4 weeks, followed by adding dutasteride. The primary end point was a 50% prostate-specific antigen response rate. Serum concentrations of abiraterone and its metabolites as well as HSD3B1 and SRD5A2 genotypes were measured. The association between drug metabolism and genotypes and their impact on the efficacy of combination therapy were assessed. Among 21 patients, 18 (85.7%) achieved ≥50% PSA reduction. Median time to treatment failure was not reached during the median follow-up of 15.4 months. No patients experienced grade ≥3 adverse events. Although dutasteride reduced serum 3-keto-5α-abiraterone concentrations, higher serum 3-keto-5α-abiraterone concentrations on combination therapy were associated with a shorter time to treatment failure. HSD3B1 and SRD5A2 genotypes were associated with serum Δ4-abiraterone and 3-keto-5α-abiraterone concentrations before adding dutasteride, respectively. Time to treatment failure was longer in patients with homozygous wild-type HSD3B1, but comparable between those with the SRD5A2 genotype. The promising outcomes of this study warrant further investigation of combination therapy in a randomized trial. Stratification by HSD3B1 and SRD5A2 genetic profiles might identify patients suitable for combination therapy.

Risk Allele Frequency Analysis and Risk Prediction of Single-Nucleotide Polymorphisms for Prostate Cancer

The incidence of prostate cancer (PCa) varies by ethnicity. This study aimed to provide insights into the genetic cause of PCa, which can result in differences in incidence among individuals of diverse ancestry. We collected data on PCa-associated single-nucleotide polymorphisms (SNPs) from a genome-wide association study catalog. Fisher’s exact tests were used to analyze the significance of enrichment or depletion of the effect on the allele at a given SNP. A network analysis was performed based on PCa-related SNPs that showed significant differences among ethnicities. The SNP-based polygenic risk score (PRS) was calculated, and its correlation with PCa incidence was evaluated. European, African, and East Asian populations had different heatmap patterns. Calculated PRS from the allele frequencies of PCa was the highest among Africans, followed by Europeans, and was the lowest among East Asians. PRS was positively correlated with the incidence and mortality of PCa. Network analysis revealed that AR, CDKN1B, and MAD1L1 are genes related to ethnic differences in PCa. The incidence and mortality of PCa showed a strong correlation with PRS according to ethnicity, which may suggest the effect of genetic factors, such as the AR gene, on PCa pathogenesis.

Clinical impact of HSD3B1 polymorphism by metastatic volume and somatic HSD3B1 alterations in advanced prostate cancer

This study aimed to investigate the significance of HSD3B1 gene status including germline polymorphism and somatic alterations in prostate cancer. Patients with prostate cancer treated with androgen-deprivation therapy, as well as tissues from metastatic prostate cancer, were included. Genomic DNA was extracted from cancer tissues and whole blood samples, and HSD3B1 (rs1047303, 1245C) was genotyped by Sanger sequencing. The association of HSD3B1 genotype with progression-free survival according to metastatic volume was examined. Copy number alteration and gene expression of HSD3B1 were examined in prostate cancer cells and public datasets. Among 194 patients, 121 and 73 patients were categorized into low- and high-volume diseases respectively. In multivariate analysis, the adrenal-permissive genotype (AC/CC) was significantly associated with increased risk of progression compared with the adrenal-restrictive genotype (AA) in low volume, but not high-volume diseases. Somatic mutation in HSD3B1 was detected at least in two cases of castration-resistant prostate cancer tissues. HSD3B1 amplification and overexpression were detected in castration-resistant prostate cancer cells and tissues. The current findings suggest that both germline and somatic alterations of HSD3B1 may cooperatively promote castration resistance in prostate cancer and HSD3B1 as a promising biomarker for precision medicine, warranting further investigations.

The association between missense polymorphisms in SRD5A2 and HSD3B1 and treatment failure with abiraterone for castration-resistant prostate cancer

Missense polymorphism in HSD3B1, encoding 3β-hydroxysteroid dehydrogenase-1, was associated with outcome after abiraterone treatment. Other androgen-metabolizing enzymes may be involved in therapeutic effect in abiraterone. In this study, we investigated the significance of polymorphisms in genes involved in androgen and abiraterone metabolisms in prostate cancer patients treated with abiraterone. A total of 99 Japanese male castration-resistant prostate cancer patients treated with abiraterone between 2014 and 2018 were included. Genomic DNA was obtained from whole blood samples, and genotyping on SRD5A2 (rs523349), CYP17A1 (rs743572), CYP17A1 (rs2486758), and AKR1C3 (rs12529) was performed by PCR-based technique. Among the 99 patients, 32 (32.3%), 49 (49.5%), and 18 patients (18.2%) carried GG, GC, and CC alleles in SRD5A2, respectively. CC allele was associated with lower risk of treatment failure (hazard ratio, 0.43; 95% confidence interval, 0.20-0.87; P = 0.017) on multivariate analyses, compared with GG/GC alleles. In the combination model using HSD3B1 and SRD5A2 polymorphisms, compared with the combination of AA in HSD3B1 and GG/GC in SRD5A2, other combinations were associated with lower risk of treatment failure (hazard ratio, 0.34; 95% confidence interval, 0.17-0.62; P = 0.0003) on multivariate analyses. This study showed that SRD5A2 genetic variation was associated with the risk of treatment failure in abiraterone. Combinational use of genetic variation in HSD3B1 with SRD5A2 genetic variation augmented the ability of prognostic stratification.

Epidemiology and genomics of prostate cancer in Asian men

Prostate cancer is a global health problem, but incidence varies considerably across different continents. Asia is traditionally considered a low-incidence area, but the incidence and mortality of prostate cancer have rapidly increased across the continent. Substantial differences in epidemiological features have been observed among different Asian regions, and incidence, as well as mortality-to-incidence ratio, is associated with the human development index. Prostate cancer mortality decreased in Japan and Israel from 2007 to 2016, but mortality has increased in Thailand, Kyrgyzstan and Uzbekistan over the same period. Genomic analyses have shown a low prevalence of ERG oncoprotein in the East Asian population, alongside a low rate of PTEN loss, high CHD1 enrichments and high FOXA1 alterations. Contributions from single-nucleotide polymorphisms to prostate cancer risk vary with ethnicity, but germline mutation rates of DNA damage repair genes in metastatic prostate cancer are comparable in Chinese and white patients from the USA and UK. Pharmacogenomic features of testosterone metabolism might contribute to disparities seen in the response to androgen deprivation between East Asian men and white American and European men. Overall, considerable diversity in epidemiology and genomics of prostate cancer across Asia defines disease characteristics in these populations, but studies in this area are under-represented in the literature. Taking into account this intracontinental and intercontinental heterogeneity, translational studies are required in order to develop ethnicity-specific treatment strategies.

Prostate Cancer Mortality Associated with Aggregate Polymorphisms in Androgen-Regulating Genes: The Atherosclerosis Risk in the Communities (ARIC) Study

Genetic variations in androgen metabolism may influence prostate cancer (PC) prognosis. Clinical studies consistently linked PC prognosis with four single nucleotide polymorphisms (SNPs) in the critical androgen-regulating genes: 3-beta-hydroxysteroid dehydrogenase (HSD3B1) rs1047303, 5-alpha-reductase 2 (SRD5A2) rs523349, and solute carrier organic ion (SLCO2B1) rs1789693 and rs12422149. We tested the association of four androgen-regulating SNPs, individually and combined, with PC-specific mortality in the ARIC population-based prospective cohort. Men diagnosed with PC (N = 622; 79% White, 21% Black) were followed for death (N = 350) including PC death (N = 74). Cox proportional hazards regression was used to estimate hazard ratios (HR) and 95%CI adjusting for center, age, stage, and grade at diagnosis using separate hazards for races. A priori genetic risk score (GRS) was created as the unweighted sum of risk alleles in the four pre-selected SNPs. The gain-of-function rs1047303C allele was associated PC-specific mortality among men with metastatic PC at diagnosis (HR = 4.89 per risk allele, p = 0.01). Higher GRS was associated with PC-specific mortality (per risk allele: HR = 1.26, p = 0.03). We confirmed that the gain-of-function allele in HSD3B1 rs1047303 is associated with greater PC mortality in men with metastatic disease. Additionally, our findings suggest a cumulative effect of androgen-regulating genes on PC-specific mortality; however, further validation is required.

Genetic Polymorphisms and Pharmacotherapy for Prostate Cancer

The therapeutic landscape of pharmacotherapy for prostate cancer has dramatically evolved, and multiple therapeutic options have become available for prostate cancer patients. Therefore, useful biomarkers to identify suitable candidates for treatment are required to maximize the efficacy of pharmacotherapy. Genetic polymorphisms such as single-nucleotide polymorphisms (SNPs) and tandem repeats have been shown to influence the therapeutic effects of pharmacotherapy for prostate cancer patients. For example, genetic polymorphisms in the genes involved in androgen receptor signaling are reported to be associated with the therapeutic outcome of androgen-deprivation therapy as well as androgen receptor-pathway inhibitors. In addition, SNPs in genes involved in drug metabolism and efflux pumps are associated with therapeutic effects of taxane chemotherapy. Thus, genetic polymorphisms such as SNPs are promising biomarkers to realize personalized medicine. Here, we overview the current findings on the influence of genetic polymorphisms on the outcome of pharmacotherapy for prostate cancer and discuss current issues as well as future visions in this field.

In vitro and in vivo investigation of the therapeutic mechanism of Lycium Chinense and Cuscutae Semen on oligoasthenozoospermia

Through network pharmacology research, we found that CYP19, CYP17, AR and SRD5A2 were potential targets for lycium chinense-cuscutae semen (LC-CS) treatment of oligoasthenozoospermia. Using in vitro and in vivo experiments, tripterygium glycosides were used to induce spermatogenic dysfunction models in GC-1spg cells and SD male rats, respectively, and LC-CS was used to intervene in a spermatogenic dysfunction model. In vitro, LC-CS could repair the ultrastructure of GC-1spg cells damaged by tripterygium glycosides (TG). Compared with TG group, LC-CS could upregulate protein and mRNA expression of CYP19, CYP17, AR and SRD5A2. In vivo, compared with TG, the body mass, testicular mass and epididymal weights of rats in TG + LC-CS increased. Progressive motility + nonprogressive motility spermatozoon (PR + NP) of TG + LC-CS were upregulate than TG. The levels of FSH, LH and testosterone in TG + LC-CS were upregulate than TG. LC-CS can repair the ultrastructure of spermatogonia damaged by TG (the above results are statistically significant, p <.05). Results of H&E staining and TEM showed that the morphology and ultrastructure of testicular tissue in TG + LC-CS were better than that in TG. Compared with TG, LC-CS could upregulate the expression of CYP19, CYP17, AR and SRD5A2 proteins and mRNA.

Metabolic regulation of prostate cancer heterogeneity and plasticity

Metabolic reprogramming is one of the main hallmarks of cancer cells. It refers to the metabolic adaptations of tumor cells in response to nutrient deficiency, microenvironmental insults, and anti-cancer therapies. Metabolic transformation during tumor development plays a critical role in the continued tumor growth and progression and is driven by a complex interplay between the tumor mutational landscape, epigenetic modifications, and microenvironmental influences. Understanding the tumor metabolic vulnerabilities might open novel diagnostic and therapeutic approaches with the potential to improve the efficacy of current tumor treatments. Prostate cancer is a highly heterogeneous disease harboring different mutations and tumor cell phenotypes. While the increase of intra-tumor genetic and epigenetic heterogeneity is associated with tumor progression, less is known about metabolic regulation of prostate cancer cell heterogeneity and plasticity. This review summarizes the central metabolic adaptations in prostate tumors, state-of-the-art technologies for metabolic analysis, and the perspectives for metabolic targeting and diagnostic implications.

Genomic characteristics revealed by targeted exon sequencing of testicular germ cell tumors in Japanese men

OBJECTIVE

To investigate the somatic mutation profiles of testicular germ cell tumors in Japanese men.

METHODS

We analyzed the somatic missense mutation profile of testicular germ cell tumors among 21 Japanese men with seminoma (n = 14), pure embryonic carcinoma (n = 3) and mixed testicular germ cell tumor (n = 4) by targeted next-generation sequencing of 409 cancer-related genes covering 1.23 Mb of the genome.

RESULTS

We identified a total of 22 missense mutations in 21 primary testicular germ cell tumor samples (0.89 mutations/Mb), of which seven mutations were confirmed to be absent from the germline. KIT:p.Asn822Tyr, KIT:p.Leu576Pro, PIK3CA:p.Glu542Lys and FBXW7:p.Arg505His were statistically and functionally potential. A total of 18 missense mutations were previously unknown in testicular germ cell tumors. PDGFRA amplification from one patient with seminoma was detected. KIT, BCR,PIK3CG, PIK3CA and PDGFRA mutations involved in aberrant signaling of the KIT-PI3K-AKT pathway was detected in 27.3% of detected mutations.

CONCLUSIONS

The present investigation identified a low mutation rate in testicular germ cell tumors among Asian patients, 18 novel mutations and PDGFRA amplification. Limitations of the present study are the small sample and missing normal DNA for some testicular germ cell tumors.

Polymorphisms in androgen metabolism genes with serum testosterone levels and prognosis in androgen-deprivation therapy

OBJECTIVE

Androgen metabolism is a key component in therapeutic resistance to androgen deprivation therapy (ADT). This study aimed to reveal the significance of genetic polymorphisms in genes involved in androgen metabolism, including CYP17A1, AKR1C3, and HSD17B, on serum testosterone levels during ADT, as well as the prognosis of men undergoing ADT for metastatic prostate cancer (CaP).

MATERIALS AND METHODS

This study included 104 Japanese patients with metastatic CaP, for whom serum testosterone data during ADT were available for 80 patients. The association of CYP17A1 (rs743572), AKR1C3 (rs12529), HSD17B1 (rs605059), HSD17B3 (rs2066479), and HSD17B4 (rs7737181) with serum testosterone levels during ADT and prognosis (progression-free survival and overall survival) was examined. Enzymatic activity in AKR1C3 H5Q was examined using recombinant protein.

RESULTS

Homozygous wild-type (GG allele; median [interquartile range], 12.0 ng/ml [8.0-19.0 ng/ml]) AKR1C3 rs12529 was associated with higher serum testosterone levels during ADT compared with variant-type (GC/CC alleles; median [interquartile range], 9.0 ng/ml [6.4-10.8 ng/ml]). Consistently, variant-type (GC/CC alleles) AKR1C3 rs12529 showed significantly lower risk of progression (hazard ratio [95% confidence interval], 0.47 [0.24-0.96], P = 0.039) compared with homozygous wild-type (GG allele) on multivariate analysis. Meanwhile, other genetic variations were associated with neither serum testosterone during ADT nor prognosis. Enzyme activity of wild-type AKR1C3 was comparable to the H5Q mutant.

CONCLUSIONS

Taken together, this study demonstrated that AKR1C3 polymorphism, which was associated with serum testosterone levels during ADT, may be a prognostic factor of the progression to castration-resistant prostate cancer in Japanese men with metastatic CaP.

Germline polymorphisms associated with impaired survival outcomes and somatic tumor alterations in advanced prostate cancer

INTRODUCTION

Germline variants in androgen metabolism genes may influence clinical response to androgen deprivation therapy (ADT) in advanced prostate cancer. We sought to investigate the prognostic significance of germline variants in androgen metabolism genes with respect to overall survival (OS) after ADT, and to associate germline variants with tumor genomic features.

METHODS

Germline and somatic whole-genome sequencing (WGS) data were evaluated in a cohort of 101 men with metastatic castration-resistant prostate cancer (mCRPC). Survival analyses were performed to identify polymorphisms associated with impaired OS after primary ADT. Germline variants found to be prognostic of OS were associated with tumor somatic DNA-sequence alterations based on WGS performed on paired metastasis biopsies from the same 101 patients. Gene set enrichment analysis was performed based on tumor RNA-sequencing data to identify genomic pathways differentially expressed in patients with germline variants.

RESULTS

A comprehensive literature review identified 17 candidate polymorphisms in nine androgen metabolism genes that have been previously shown to have an association with response to ADT in prostate cancer. Of these, the variant rs1856888 allele located 13 kb upstream of HSD3B1 was found to be significantly associated with impaired OS (P = 0.029). Variant rs1856888 was commonly co-inherited with the well-characterized HSD3B1(1245A>C) polymorphism, and there was a trend toward shorter median OS in patients with HSD3B1(1245A>C) compared with homozygous wild-type patients (P = 0.052). While HSD3B1 germline variants were not associated with common somatic tumor DNA alterations, they were associated with increased tumor expression of cell proliferation and cell cycle genes.

CONCLUSIONS

This study presents a comprehensive assessment of germline variants in androgen metabolism genes and highlights HSD3B1 polymorphisms as prognostic of OS after ADT and associated with an aggressive gene expression tumor profile in mCRPC.

Methylation of SRD5A2 promoter predicts a better outcome for castration-resistant prostate cancer patients undergoing androgen deprivation therapy

PURPOSE

To determine whether SRD5A2 promoter methylation is associated with cancer progression during androgen deprivation therapy (ADT) in CRPC.

PATIENTS AND METHODS

In a Local CRPC cohort, 42 prostatic specimens were collected from patients who were diagnosed as CRPC and underwent transurethral resection of the prostate (TURP) at Massachusetts General Hospital (MGH). In a metastatic CRPC (Met CRPC) cohort, 12 metastatic biopsies were collected from CRPC patients who would be treated with abiraterone plus dutasteride (Clinical Trial NCT01393730). As controls, 36 benign prostatic specimens were collected from patients undergoing prostate reduction surgery for symptoms of bladder outlet obstruction secondary to benign prostatic hyperplasia (BPH). The methylation status of cytosine-phosphate-guanine (CpG) site(s) at SRD5A2 promoter regions was tested.

RESULTS

Compared with benign prostatic tissue, CRPC samples demonstrated higher SRD5A2 methylation in the whole promoter region (Local CRPC cohort: P < 0.001; Met CRPC cohort: P <0.05). In Local CRPC cohort, a higher ratio of methylation was correlated with better OS (R2 = 0.33, P = 0.013). Hypermethylation of specific regions (nucleotides -434 to -4 [CpG# -39 to CpG# -2]) was associated with a better OS (11.3±5.8 vs 6.4±4.4 years, P = 0.001) and PFS (8.4±5.4 vs 4.5±3.9 years, P = 0.003) with cutoff value of 37.9%. Multivariate analysis showed that SRD5A2 methylation was associated with OS independently (whole promoter region: P = 0.035; specific region: P = 0.02).

CONCLUSION

Our study demonstrate that SRD5A2 methylation in promoter regions, specifically at CpG# -39 to -2, is significantly associated with better survival for CRPC patients treated with ADT. Recognition of epigenetic modifications of SRD5A2 may affect the choices and sequence of available therapies for management of CRPC.

A Novel Gene Signature-Based Model Predicts Biochemical Recurrence-Free Survival in Prostate Cancer Patients after Radical Prostatectomy

Abstract: Currently, decision-making regarding biochemical recurrence (BCR) following prostatectomy relies solely on clinical parameters. We therefore attempted to develop an integrated prediction model based on a molecular signature and clinicopathological features, in order to forecast the risk for BCR and guide clinical decision-making for postoperative therapy. Using high-throughput screening and least absolute shrinkage and selection operator (LASSO) in the training set, a novel gene signature for biochemical recurrence-free survival (BCRFS) was established. Validation of the prognostic value was performed in five other independent datasets, including our patient cohort. Multivariate Cox regression analysis was performed to evaluate the importance of risk for BCR. Time-dependent receiver operating characteristic (tROC) was used to evaluate the predictive power. In combination with relevant clinicopathological features, a decision tree was built to improve the risk stratification. The gene signature exhibited a strong capacity for identifying high-risk BCR patients, and multivariate Cox regression analysis demonstrated that the gene signature consistently acted as a risk factor for BCR. The decision tree was successfully able to identify the high-risk subgroup. Overall, the gene signature established in the present study is a powerful predictor and risk factor for BCR after radical prostatectomy.

The impact of genetic polymorphism on CYP19A1 in androgen-deprivation therapy among Japanese men

PURPOSE

Inadequate suppression of testosterone during androgen-deprivation therapy impairs its efficacy. This study investigated the significance of genetic polymorphism in CYP19A1, which encodes aromatase that catalyzes androgens into estrogens, among men treated with primary ADT for metastatic prostate cancer.

METHODS

This study included 80 Japanese patients with metastatic prostate cancer whose serum testosterone levels during ADT were available. The association of CYP19A1 gene polymorphism (rs1870050) with clinicopathological parameters including serum testosterone levels during ADT as well as progression-free survival and overall survival was examined.

RESULTS

Serum testosterone levels during ADT of men carrying homozygous wild-type (AA) in the CYP19A1 gene [median (interquartile range); 11.6 (8.3-20.3) ng/dl] were higher than those in men carrying the heterozygous/homozygous variant (AC/CC) [median (interquartile range); 10.0 (6.4-12.8) ng/dl]. When adjusted by Gleason score, initial PSA, M-stage and serum testosterone level during ADT, heterozygous/homozygous variant (AC/CC) in the CYP19A1 gene was associated with a lower risk of progression to castration resistance [hazard ratio (95% confidence interval), 0.53 [0.29-0.92], p = 0.025], but not to any-cause death [hazard ratio (95% confidence interval), 0.74 [0.36-1.49], p = 0.40].

CONCLUSIONS

These findings suggest that genetic variation in CYP19A1 (rs1870050) might affect the prognosis of patients with metastatic prostate cancer when treated with ADT by regulating serum testosterone levels.

Association of Missense Polymorphism in HSD3B1 With Outcomes Among Men With Prostate Cancer Treated With Androgen-Deprivation Therapy or Abiraterone

IMPORTANCE

Recently, genetic polymorphism in HSD3B1 encoding 3β-hydroxysteroid dehydrogenase-1 has been shown to be associated with oncological outcome when treated with androgen-deprivation therapy (ADT) for prostate cancer. Upfront abiraterone combined with ADT has proved survival benefit. However, its effect on oncological outcome among different ethnicities and in abiraterone treatment remain unclear.

OBJECTIVE

To investigate the significance of missense polymorphism in HSD3B1 gene among men treated with primary ADT or abiraterone.

DESIGN, SETTING, AND PARTICIPANTS

This prognostic study included Japanese patients with metastatic hormone-sensitive prostate cancer between June 1993 and July 2005 and with castration-resistant prostate cancer between September 2014 and February 2018. Genome DNA was obtained from patient whole blood samples, and genotyping on HSD3B1 (rs1047303, 1245C) was performed by Sanger sequencing.

EXPOSURES

Primary ADT for metastatic hormone-sensitive prostate cancer and abiraterone for castration-resistant prostate cancer.

MAIN OUTCOMES AND MEASURES

The association of genotype in HSD3B1 with clinicopathological parameters and oncological outcome, including prostate-specific antigen response, progression-free survival, treatment failure-free survival, and overall survival was examined.

RESULTS

Of 203 men, 104 were in the primary ADT cohort (median [interquartile range] age, 72 [67-76] years) and 99 men were in the abiraterone group (median [interquartile range] age, 74 [67-80] years). Most patients carried metastatic lesions in each cohort. Among the cohort of primary ADT, men carrying heterozygous and homozygous variant types in HSD3B1 gene showed higher progression risk (hazard ratio [HR], 2.34; 95% CI, 1.08-4.49; P = .03) but not any-caused death risk (HR, 1.36; 95% CI, 0.52-2.92; P = .50), compared with men carrying homozygous wild type. In contrast, among the abiraterone cohort, men carrying variant type in HSD3B1 gene showed lower progression risk (HR, 0.32; 95% CI, 0.12-0.69; P = .006) and lower all-cause mortality risk (HR, 0.40; 95% CI, 0.13-0.94; P = .04) compared with men carrying homozygous wild type.

CONCLUSIONS AND RELEVANCE

This study showed that HSD3B1 genetic variant is distinctly associated with oncological outcome between primary ADT and abiraterone in Japanese men, suggesting universal significance among different ethnicities in primary ADT, as well as promise as a predictive biomarker of ADT and abiraterone.

Systems Oncology: Bridging Pancreatic and Castrate Resistant Prostate Cancer

Large investments by pharmaceutical companies in the development of new antineoplastic drugs have not been resulting in adequate advances of new therapies. Despite the introduction of new methods, technologies, translational medicine and bioinformatics, the usage of collected knowledge is unsatisfactory. In this paper, using examples of pancreatic ductal adenocarcinoma (PaC) and castrate-resistant prostate cancer (CRPC), we proposed a concept showing that, in order to improve applicability of current knowledge in oncology, the re-clustering of clinical and scientific data is crucial. Such an approach, based on systems oncology, would include bridging of data on biomarkers and pathways between different cancer types. Proposed concept would introduce a new matrix, which enables combining of already approved therapies between cancer types. Paper provides a (a) detailed analysis of similarities in mechanisms of etiology and progression between PaC and CRPC, (b) diabetes as common hallmark of both cancer types and (c) knowledge gaps and directions of future investigations. Proposed horizontal and vertical matrix in cancer profiling has potency to improve current antineoplastic therapy efficacy. Systems biology map using Systems Biology Graphical Notation Language is used for summarizing complex interactions and similarities of mechanisms in biology of PaC and CRPC.

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.

Gene polymorphisms in antioxidant enzymes correlate with the efficacy of androgen-deprivation therapy for prostate cancer with implications of oxidative stress

Background

Oxidative stress mitigated by antioxidant enzymes is thought to be involved in the progression to castration-resistant prostate cancer (CRPC) during androgen-deprivation therapy (ADT). This study investigated the association between genetic variations in antioxidant enzymes and the efficacy of ADT as well as its biological background.

Patients and methods

The non-synonymous or promoter-locating polymorphisms of antioxidant enzymes were examined as well as the time to CRPC progression and overall survival in 104 and 92 patients treated with ADT for metastatic and non-metastatic prostate cancer, respectively. In addition, intracellular reactive oxygen species and expression levels of antioxidant enzymes were examined in castration-resistant and enzalutamide-resistant cells.

Results

In metastatic prostate cancer, the AG/GG allele in GSTM3 rs7483 and CT/TT allele in CAT rs564250 were associated with a significantly lower risk of progression to CRPC and all-cause death compared with homozygotes of the major AA allele (hazard ratio [HR]; [95% confidence interval (CI)], 0.55 [0.34-0.86], P = 0.0086) and CC allele (HR; [95% CI], 0.48 [0.24-0.88], P = 0.016), respectively. On multivariate analyses, only GSTM3 rs7483 was associated with significant progression risk (AG/GG versus AA; HR; [95% CI], 0.45 [0.25-0.79], P = 0.0047) even after Bonferroni adjustment. In non-metastatic prostate cancer, the AG/GG allele in GSTM3 rs7483 was associated with a significantly lower risk of progression to CRPC (HR; [95% CI], 0.35 [0.10-0.93], P = 0.034) and all-cause death (HR; [95% CI], 0.26 [0.041-0.96], P = 0.043) compared with the AA allele. Intracellular reactive oxygen species levels were increased, accompanied with augmented GSTM3 expression in both castration-resistant and enzalutamide-resistant cells.

Conclusions

Differential activity of antioxidant enzymes caused by the polymorphism in GSTM3 may contribute to resistance to hormonal therapy through oxidative stress. The GSTM3 rs7483 polymorphism may be a promising biomarker for prostate cancer patients treated with ADT.

A genetic variant in SLC28A3, rs56350726, is associated with progression to castration-resistant prostate cancer in a Korean population with metastatic prostate cancer

Background

Genetic variation which related with progression to castration-resistant prostate cancer (CRPC) during androgen-deprivation therapy (ADT) has not been elucidated in patients with metastatic prostate cancer (mPCa). Therefore, we assessed the association between genetic variats in mPCa and progession to CRPC.

Results

Analysis of exome genotypes revealed that 42 SNPs were significantly associated with mPCa. The top five polymorphisms were statistically significantly associated with metastatic disease. In addition, one of these SNPs, rs56350726, was significantly associated with time to CRPC in Kaplan-Meier analysis (Log-rank test, p = 0.011). In multivariable Cox regression, rs56350726 was strongly associated with progression to CRPC (HR = 4.172 95% CI = 1.223-14.239, p = 0.023).

Materials and Methods

We assessed genetic variation among 1000 patients with PCa with or without metastasis, using 242,221 single nucleotide polymorphisms (SNPs) on the custom HumanExome BeadChip v1.0 (Illuminam Inc.). We analyzed the time to CRPC in 110 of the 1000 patients who were treated with ADT. Genetic data were analyzed using unconditional logistic regression and odds ratios calculated as estimates of relative risk of metastasis. We identified SNPs associated with metastasis and analyzed the relationship between these SNPs and time to CRPC in mPCa.

Conclusions

Based on a genetic variation, the five top SNPs were observed to associate with mPCa. And one (SLC28A3, rs56350726) of five SNP was found the association with the progression to CRPC in patients with mPCa.

Role of the Androgen-Androgen Receptor Axis in the Treatment Resistance of Advanced Prostate Cancer: From Androgen-Dependent to Castration Resistant and Further

After the introduction of prostate-specific antigen (PSA) screening, prostate cancer diagnosis has shifted to early and curative stages, although 10-20% of patients still present with metastatic and incurable cancer. Prostate cancer is androgen-dependent, and most patients with prostate cancer initially respond to androgen deprivation therapy (ADT). After 1-2 years of the treatment, advanced prostate cancer eventually progresses to castration resistant prostate cancer (CRPC). A variety of mechanisms of progression from androgen-dependent prostate cancer to CRPC under ADT have been postulated, and the key pathway is re-activation of the androgen-androgen receptor (AR) axis, for example, caused by AR mutation/overexpression/splice variants, altered expression of AR cofactors, and increased production of androgens. Recently approved new agents, such as the hormonal agents abiraterone and enzalutamide and the chemotherapeutic agent cabazitaxel, have demonstrated survival benefit in men with CRPC. However, the prolongation of survival times provided with these agents is limited because of the treatment resistance. Androgen-AR axis still plays a pivotal role in the resistance to the new agents for CRPC. To improve the prognosis of patients with CRPC, intensive research to identify effective agents, treatment strategies, and useful predictive biomarkers to select the patients who can benefit from such treatments are required. Additional clinical data, with a better understanding of the biology of CRPC, may provide better CRPC treatment outcomes. This article reviews the underlying mechanisms of treatment resistance and future direction of CRPC treatments.