Association of HSD3B1 Genotype With Response to Androgen-Deprivation Therapy for Biochemical Recurrence After Radiotherapy for Localized Prostate Cancer

Adrenal-Permissive Germline HSD3B1 Allele and Prostate Cancer Outcomes

Importance

The adrenal androgen-metabolizing 3β-hydroxysteroid dehydrogenase-1 enzyme, encoded by the HSD3B1 gene, catalyzes the rate-limiting step necessary for synthesizing nontesticular testosterone and dihydrotestosterone production. The common adrenal-permissive HSD3B1(1245C) allele is responsible for encoding the 3β-HSD1 protein with decreased susceptibility to degradation resulting in higher extragonadal androgen synthesis. Retrospective studies have suggested an association of the HSD3B1 adrenal-permissive homozygous genotype with androgen deprivation therapy resistance in prostate cancer.

Objective

To evaluate differences in mortality outcomes by HSD3B1 genetic status among men with prostate cancer.

Design, Setting, and Participants

This cohort study of patients with prostate cancer who were enrolled in the Million Veteran Program within the Veterans Health Administration (VHA) system between 2011 and 2023 collected genotyping and phenotyping information.

Exposure

HSD3B1 genotype status was categorized as AA (homozygous adrenal-restrictive), AC (heterozygous adrenal-restrictive), or CC (homozygous adrenal-permissive).

Main Outcomes and Measures

The primary outcome of this study was prostate cancer-specific mortality (PCSM), defined as the time from diagnosis to death from prostate cancer, censored at the date of last VHA follow-up. Secondary outcomes included incidence of metastases and PCSM in predefined subgroups.

Results

Of the 5287 participants (median [IQR] age, 69 [64-74] years), 402 (7.6%) had the CC genotype, 1970 (37.3%) had the AC genotype, and 2915 (55.1%) had the AA genotype. Overall, the primary cause of death for 91 patients (1.7%) was prostate cancer. Cumulative incidence of PCSM at 5 years after prostate cancer diagnosis was higher among men with the CC genotype (4.0%; 95% CI, 1.7%-6.2%) compared with the AC genotype (2.1%; 95% CI, 1.3%-2.8%) and AA genotype (1.9%; 95% CI, 1.3%-2.4%) (P = .02). In the 619 patients who developed metastatic disease at any time, the cumulative incidence of PCSM at 5 years was higher among patients with the CC genotype (36.0%; 95% CI, 16.7%-50.8%) compared with the AC genotype (17.9%; 95% CI, 10.5%-24.7%) and AA genotype (18.5%; 95% CI, 12.0%-24.6%) (P = .01).

Conclusions and Relevance

In this cohort study of US veterans undergoing treatment for prostate cancer at the VHA, the HSD3B1 CC genotype was associated with inferior outcomes. The HSD3B1 biomarker may help identify patients who may benefit from therapeutic targeting of 3β-hydroxysteroid dehydrogenase-1 and the androgen-signaling axis.

Chronic hypoxia stabilizes 3βHSD1 via autophagy suppression

Progression of prostate cancer depends on androgen receptor, which is usually activated by androgens. Therefore, a mainstay treatment is androgen deprivation therapy. Unfortunately, despite initial treatment response, resistance nearly always develops, and disease progresses to castration-resistant prostate cancer (CRPC), which remains driven by non-gonadal androgens synthesized in prostate cancer tissues. 3β-Hydroxysteroid dehydrogenase/Δ5-->4 isomerase 1 (3βHSD1) catalyzes the rate-limiting step in androgen synthesis. However, how 3βHSD1, especially the "adrenal-permissive" 3βHSD1(367T) that permits tumor synthesis of androgen from dehydroepiandrosterone (DHEA), is regulated at the protein level is not well understood. Here, we investigate how hypoxia regulates 3βHSD1(367T) protein levels. Our results show that, in vitro, hypoxia stabilizes 3βHSD1 protein by suppressing autophagy. Autophagy inhibition promotes 3βHSD1-dependent tumor progression. Hypoxia represses transcription of autophagy-related (ATG) genes by decreasing histone acetylation. Inhibiting deacetylase (HDAC) restores ATG gene transcription under hypoxia. Therefore, HDAC inhibition may be a therapeutic target for hypoxic tumor cells.

Active DHEA uptake in the prostate gland correlates with aggressive prostate cancer

Strategies for patient stratification and early intervention are required to improve clinical benefits for patients with prostate cancer. Here, we found that active DHEA utilization in the prostate gland correlated with tumor aggressiveness at early disease stages, and 3βHSD1 inhibitors were promising for early intervention. [3H]-labeled DHEA consumption was traced in fresh prostatic biopsies ex vivo. Active DHEA utilization was more frequently found in patients with metastatic disease or therapy-resistant disease. Genetic and transcriptomic features associated with the potency of prostatic DHEA utilization were analyzed to generate clinically accessible approaches for patient stratification. UBE3D, by regulating 3βHSD1 homeostasis, was discovered to be a regulator of patient metabolic heterogeneity. Equilin suppressed DHEA utilization and inhibited tumor growth as a potent 3βHSD1 antagonist, providing a promising strategy for the early treatment of aggressive prostate cancer. Overall, our findings indicate that patients with active prostatic DHEA utilization might benefit from 3βHSD1 inhibitors as early intervention.

Intratumoral androgen biosynthesis associated with 3β-hydroxysteroid dehydrogenase 1 promotes resistance to radiotherapy in prostate cancer

Half of all men with advanced prostate cancer (PCa) inherit at least 1 copy of an adrenal-permissive HSD3B1 (1245C) allele, which increases levels of 3β-hydroxysteroid dehydrogenase 1 (3βHSD1) and promotes intracellular androgen biosynthesis. Germline inheritance of the adrenally permissive allele confers worse outcomes in men with advanced PCa. We investigated whether HSD3B1 (1245C) drives resistance to combined androgen deprivation and radiotherapy. Adrenally permissive 3βHSD1 enhanced resistance to radiotherapy in PCa cell lines and xenograft models engineered to mimic the human adrenal/gonadal axis during androgen deprivation. The allele-specific effects on radiosensitivity were dependent on availability of DHEA, the substrate for 3βHSD1. In lines expressing the HSD3B1 (1245C) allele, enhanced expression of DNA damage response (DDR) genes and more rapid DNA double-strand break (DSB) resolution were observed. A correlation between androgen receptor (AR) expression and increased DDR gene expression was confirmed in 680 radical prostatectomy specimens. Treatment with the nonsteroidal antiandrogen enzalutamide reversed the resistant phenotype of HSD3B1 (1245C) PCa in vitro and in vivo. In conclusion, 3βHSD1 promotes prostate cancer resistance to combined androgen deprivation and radiotherapy by upregulating DNA DSB repair. This work supports prospective validation of early combined androgen blockade for high-risk men harboring the HSD3B1 (1245C) allele.

Prospective role of 3βHSD1 in prostate cancer precision medicine

BACKGROUND

Prostate cancer is addicted to androgens. The steroidogenic enzyme 3β-hydroxysteroid dehydrogenase 1 (3βHSD1) recognizes pregnenolone, dehydroepiandrosterone (DHEA), and steroidal medicine abiraterone as substrates to accelerate disease progression.

METHODS

References for this review were identified through searches of PubMed with the search terms "prostate cancer", "HSD3B1", and "3bHSD1" from 1990 until June, 2022.

RESULTS

Genotype of 3βHSD1 has been reported to correlate with tumor aggressiveness of advanced prostate cancer in multiple clinical scenarios. The ethnic differences and limitations of using 3βHSD1 genotype as a prognostic biomarker have been discussed here. The activity of 3βHSD1 increases in patients treated with abiraterone and enzalutamide, giving rise to treatment resistance. Further elucidation of 3βHSD1 regulatory mechanisms will shed light on more approaches for disease intervention. We also review the recent advance on 3βHSD1 inhibitors and targeting 3βHSD1 for prostate cancer management. Novel 3βHSD1 inhibitors will be needed to provide additional options for prostate cancer management.

CONCLUSION

3βHSD1 is both a predictive biomarker and a promising therapeutic target for prostate cancer.

Association Between Adrenal-Restrictive HSD3B1 Inheritance and Hormone-Independent Subtypes of Endometrial and Breast Cancer

BACKGROUND

The germline variant rs1047303 (HSD3B1[1245A/C]), restricting or enabling production of potent androgens and estrogens from adrenal precursors, affects outcomes of castration-resistant prostate cancer and is associated with estrogen receptor positivity in postmenopausal breast cancer. Like breast cancer, endometrial cancer is another malignancy with hormone-dependent and hormone-independent subtypes. We hypothesized that adrenal-restrictive HSD3B1 genotype would associate with hormone-independent cancer subtypes.

METHODS

We employed a previously described classification of tumors in The Cancer Genome Atlas into genomic clusters. We determined HSD3B1 genotype frequencies by endometrial cancer genomic cluster and calculated the odds per adrenal-restrictive A allele for the largely hormone-independent copy-number (CN) high subtype vs other subtypes. An equivalent analysis was performed for the genomically similar, hormone-independent basal breast cancer subtype. Last, we performed survival analyses for UK Biobank participants with endometrial cancer by HSD3B1 genotype. All statistical tests were 2-sided.

RESULTS

The adrenal-restrictive HSD3B1(1245A) allele was associated with the CN-high endometrial cancer subtype (odds ratio [OR] = 1.63, 95% confidence interval [CI] = 1.14 to 2.32; P = .007). Similarly, HSD3B1(1245A) was associated with the basal breast cancer subtype (OR = 1.54, 95% CI = 1.13 to 2.08; P = .006). In the UK Biobank, endometrial cancer patients homozygous for HSD3B1(1245A) had worse overall (hazard ratio [HR] = 1.39, 95% CI = 1.16 to 1.68; P < .001) and cancer-specific (HR = 1.39, 95% CI = 1.14 to 1.70; P = .001) survival, consistent with the A allele being enriched in the more aggressive CN-high subtype.

CONCLUSIONS

These findings suggest roles for adrenal-restrictive vs adrenal-permissive steroidogenesis, by way of rs1047303 genotype, in the development of and/or outcomes from at least 3 commonly hormone-associated types of cancer: prostate, breast, and endometrial.

Hypoxia-Reoxygenation Couples 3βHSD1 Enzyme and Cofactor Upregulation to Facilitate Androgen Biosynthesis and Hormone Therapy Resistance in Prostate Cancer

Androgen deprivation therapy suppresses tumor androgen receptor (AR) signaling by depleting circulating testosterone and is a mainstay treatment for advanced prostate cancer. Despite initial treatment response, castration-resistant prostate cancer nearly always develops and remains driven primarily by the androgen axis. Here we investigated how changes in oxygenation affect androgen synthesis. In prostate cancer cells, chronic hypoxia coupled to reoxygenation resulted in efficient metabolism of androgen precursors to produce androgens and activate AR. Hypoxia induced 3βHSD1, the rate-limiting androgen synthesis regulator, and reoxygenation replenished necessary cofactors, suggesting that hypoxia and reoxygenation both facilitate potent androgen synthesis. The EGLN1/VHL/HIF2α pathway induced 3βHSD1 expression through direct binding of HIF2α to the 5' regulatory region of HSD3B1 to promote transcription. Overexpression of HIF2α facilitated prostate cancer progression, which largely depended on 3βHSD1. Inhibition of HIF2α with the small-molecule PT2399 prevented prostate cancer cell proliferation. These results thus identify HIF2α as a regulator of androgen synthesis and potential therapeutic target in prostate cancer.

SIGNIFICANCE

Hypoxia followed by reoxygenation in prostate cancer drives androgen deprivation therapy resistance via increasing the rate-limiting enzyme and cofactors for androgen synthesis, revealing HIF2α as a therapeutic target to subvert resistance.

Association of HSD3B1 Genotype and Clinical Outcomes in Postmenopausal Estrogen-Receptor-Positive Breast Cancer

BACKGROUND

Homozygous inheritance of a single-nucleotide polymorphism (1245A > C) in HSD3B1 results in an adrenal permissive phenotype of increased adrenal steroid precursor conversion to potent androgens. This is associated with poor outcomes in prostate cancer. We hypothesized that inheritance of the HSD3B1 adrenal permissive genotype would similarly negatively impact breast cancer outcomes.

PATIENTS AND METHODS

Germline HSD3B1 was sequenced in 644 postmenopausal women diagnosed between 2004 and 2015 with stage I-III estrogen receptor-positive (ER⁺), HER2/neu-negative (HER2^-) breast cancer enrolled in a population-based study in western Washington. Primary endpoint was distant metastatic recurrence according to genotype. Secondary endpoint was breast cancer-specific survival. Hazard ratios (HR) were calculated using cause-specific Cox regression accounting for competing risks.

RESULTS

Adrenal restrictive genotype (homozygous wild type) was most prevalent (47%), followed by heterozygous (44%) and adrenal permissive (9%). There were no significant differences comparing demographic, tumor, or treatment characteristics apart from higher frequency of adrenal permissive genotype among non-Hispanic white participants (p = 0.04). After accounting for competing risks, the cumulative incidence of distant metastatic recurrence (15 events) was significantly higher among participants with adrenal permissive compared with the adrenal restrictive genotype (HR 4.9, 95% CI 1.32-18.4, p = 0.02). The adrenal permissive genotype was also predictive of breast cancer-specific mortality (HR 3.5, 95% CI 1.27-9.59, p = 0.02).

CONCLUSIONS

Inheritance of the HSD3B1 adrenal permissive genotype is associated with increased incidence of distant metastasis and higher cause-specific mortality in postmenopausal ER⁺/HER2^- breast cancer. Further research is necessary to understand the effect of excess adrenal androgen metabolism in promoting breast cancer growth and progression.

Management of prostate cancer by targeting 3βHSD1 after enzalutamide and abiraterone treatment

Novel strategies for prostate cancer therapy are required to overcome resistance to abiraterone and enzalutamide. Here, we show that increasing 3βHSD1 after abiraterone and enzalutamide treatment is essential for drug resistance, and biochanin A (BCA), as an inhibitor of 3βHSD1, overcomes drug resistance. 3βHSD1 activity increases in cell lines, biopsy samples, and patients after long-term treatment with enzalutamide or abiraterone. Enhanced steroidogenesis, mediated by 3βHSD1, is sufficient to impair enzalutamide function. In patients, accelerated abiraterone metabolism results in a decline of plasma abiraterone as disease progresses. BCA inhibits 3βHSD1 and suppresses prostate cancer development alone or together with abiraterone and enzalutamide. Daidzein, a BCA analog of dietary origin, is associated with higher plasma abiraterone concentrations and prevented prostate-specific antigen (PSA) increases in abiraterone-resistant patients. Overall, our results show that 3βHSD1 is a promising target to overcome drug resistance, and BCA suppresses disease progression as a 3βHSD1 inhibitor even after abiraterone and enzalutamide resistance.

Inheritance of a common androgen synthesis variant allele is associated with female COVID susceptibility in UK Biobank

Context

A sex discordance in COVID exists, with males disproportionately affected. Although sex steroids may play a role in this discordance, no definitive genetic data exist to support androgen-mediated immune suppression neither for viral susceptibility nor for adrenally produced androgens.

Objective

The common adrenal-permissive missense-encoding variant HSD3B1(1245C) that enables androgen synthesis from adrenal precursors and that has been linked to suppression of inflammation in severe asthma was investigated in COVID susceptibility and outcomes reported in the UK Biobank.

Methods

The UK Biobank is a long-term study with detailed medical information and health outcomes for over 500 000 genotyped individuals. We obtained COVID test results, inpatient hospital records, and death records and tested for associations between COVID susceptibility or outcomes and HSD3B1(1245A/C) genotype. Primary analyses were performed on the UK Biobank Caucasian cohort. The outcomes were identification as a COVID case among all subjects, COVID positivity among COVID-tested subjects, and mortality among subjects identified as COVID cases.

Results

Adrenal-permissive HSD3B1(1245C) genotype was associated with identification as a COVID case (odds ratio (OR): 1.11 per C allele, 95% CI: 1.04-1.18, P = 0.0013) and COVID-test positivity (OR: 1.09, 95% CI: 1.02-1.17, P = 0.011) in older (≥70 years of age) women. In women identified as COVID cases, there was a positive linear relationship between age and 1245C allele frequency (P < 0.0001). No associations were found between genotype and mortality or between genotype and circulating sex hormone levels.

Conclusion

Our study suggests that a common androgen synthesis variant regulates immune susceptibility to COVID infection in women, with increasingly strong effects as women age.

Regulatory genes in the androgen production, uptake and conversion (APUC) pathway in advanced prostate cancer

The androgen receptor (AR) signaling pathway regulates the progression of prostate cancer (PC). Metastatic castration-resistant prostate cancer (mCRPC) patients generally receive AR-targeted therapies (ART) or androgen-deprivation therapies (ADT) with the initial response; however, resistance is inevitably observed. Prior studies have shown activity and upregulation of a family of androgen production, uptake, and conversion - APUC genes - based on genomic analyses of patient germlines. Genetic variants of some APUC genes, such as the conversion gene, HSD3B1, predict response to second-generation androgen-targeted therapies. Studies have begun to elucidate the overall role of APUC genes, each with unique actionable enzymatic activity, in mCRPC patient outcomes. The current role and knowledge of the genetic and genomic features of APUC genes in advanced prostate cancer and beyond are discussed in this review. These studies inform of how interpreting behavior of APUC genes through genomic tools will impact the treatment of advanced prostate cancer.

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.

Adrenal-permissive HSD3B1 genetic inheritance and risk of estrogen-driven postmenopausal breast cancer

BACKGROUND

Genetics of estrogen synthesis and breast cancer risk has been elusive. The 1245A→C missense-encoding polymorphism in HSD3B1, which is common in White populations, is functionally adrenal permissive and increases synthesis of the aromatase substrate androstenedione. We hypothesized that homozygous inheritance of the adrenal-permissive HSD3B1(1245C) is associated with postmenopausal estrogen receptor–positive (ER-positive) breast cancer.

METHODS

A prospective study of postmenopausal ER-driven breast cancer was done for determination of HSD3B1 and circulating steroids. Validation was performed in 2 other cohorts. Adrenal-permissive genotype frequency was compared between postmenopausal ER-positive breast cancer, the general population, and postmenopausal ER-negative breast cancer.

RESULTS

Prospective and validation studies had 157 and 538 patients, respectively, for the primary analysis of genotype frequency by ER status in White female breast cancer patients who were postmenopausal at diagnosis. The adrenal-permissive genotype frequency in postmenopausal White women with estrogen-driven breast cancer in the prospective cohort was 17.5% (21/120) compared with 5.4% (2/37) for ER-negative breast cancer (P = 0.108) and 9.6% (429/4451) in the general population (P = 0.0077). Adrenal-permissive genotype frequency for estrogen-driven postmenopausal breast cancer was validated using Cambridge and The Cancer Genome Atlas data sets: 14.4% (56/389) compared with 6.0% (9/149) for ER-negative breast cancer (P = 0.007) and the general population (P = 0.005). Circulating androstenedione concentration was higher with the adrenal-permissive genotype (P = 0.03).

CONCLUSION

Adrenal-permissive genotype is associated with estrogen-driven postmenopausal breast cancer. These findings link genetic inheritance of endogenous estrogen exposure to estrogen-driven breast cancer.

FUNDING

National Cancer Institute, NIH (R01CA236780, R01CA172382, and P30-CA008748); and Prostate Cancer Foundation Challenge Award.

Androgens in prostate cancer: A tale that never ends

Androgens play an essential role in prostate cancer. Clinical treatments that target steroidogenesis and the androgen receptor (AR) successfully postpone disease progression. Abiraterone and enzalutamide, the next-generation androgen receptor pathway inhibitors (ARPI), emphasize the function of the androgen-AR axis even in castration-resistant prostate cancer (CRPC). However, with the increased incidence in neuroendocrine prostate cancer (NEPC) showing resistance to ARPI, the importance of androgen-AR axis in further disease management remains elusive. Herein we review the steroidogenic pathways associated with different disease stages and discuss the potential targets for disease management after manifesting resistance to abiraterone and enzalutamide.

Hormonal Therapy for Prostate Cancer

Huggins and Hodges demonstrated the therapeutic effect of gonadal testosterone deprivation in the 1940s and therefore firmly established the concept that prostate cancer is a highly androgen-dependent disease. Since that time, hormonal therapy has undergone iterative advancement, from the types of gonadal testosterone deprivation to modalities that block the generation of adrenal and other extragonadal androgens, to those that directly bind and inhibit the androgen receptor (AR). The clinical states of prostate cancer are the product of a superimposition of these therapies with nonmetastatic advanced prostate cancer, as well as frankly metastatic disease. Today's standard of care for advanced prostate cancer includes gonadotropin-releasing hormone agonists (e.g., leuprolide), second-generation nonsteroidal AR antagonists (enzalutamide, apalutamide, and darolutamide) and the androgen biosynthesis inhibitor abiraterone. The purpose of this review is to provide an assessment of hormonal therapies for the various clinical states of prostate cancer. The advancement of today's standard of care will require an accounting of an individual's androgen physiology that also has recently recognized germline determinants of peripheral androgen metabolism, which include HSD3B1 inheritance.

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.

Intracrine androgen biosynthesis and drug resistance

Castration-resistant prostate cancer is the lethal form of prostate cancer and most commonly remains dependent on androgen receptor (AR) signaling. Current therapies use AR signaling inhibitors (ARSI) exemplified by abiraterone acetate, a P450c17 inhibitor, and enzalutamide, a potent AR antagonist. However, drug resistance to these agents occurs within 12-18 months and they only prolong overall survival by 3-4 months. Multiple mechanisms can contribute to ARSI drug resistance. These mechanisms can include but are not limited to germline mutations in the AR, post-transcriptional alterations in AR structure, and adaptive expression of genes involved in the intracrine biosynthesis and metabolism of androgens within the tumor. This review focuses on intracrine androgen biosynthesis, how this can contribute to ARSI drug resistance, and therapeutic strategies that can be used to surmount these resistance mechanisms.

HSD3B1 variant and androgen-deprivation therapy outcome in prostate cancer

OBJECTIVE

Rate-limiting enzyme 3b-hydroxysteroid dehydrogenase type 1 (3βHSD1) encoded by HSD3B1 catalyzes the transition of dehydroepiandrosterone (DHEA) to dihydrotestosterone (DHT). The HSD3B1 (1245C) variant renders 3bHSD1 of resistant to ubiquitination and degradation, leading to a large amount of protein accumulation in the cell. Multiple clinical studies have shown that this mutation was correlated with resistance to androgen-deprivation therapy in prostate cancer. However, the results were not consistent depending on different treatment strategy and in some researches, the number of observed cases was relatively small.

METHODS

To determine the effects of HSD3B1 (1245C) variant on resistance to androgen-deprivation therapy in prostate cancer, we performed a meta-analysis of the available literature. Electronic database searches identified appropriately designed studies that detected HSD3B1 in prostate cancer. We conducted a systematic search of studies in the following databases: PubMed, and EMBASE published until August 10, 2020 using the following search terms: (HSD3B1 AND ((((prostate cancer) OR prostatic neoplasm) OR prostatic carcinoma) OR prostatic cancer).

RESULTS

Eight researches were included in this research. The result validated that the HSD3B1 (1245C) variant allele was associated with a shorter PFS (HR, 1.97; 95% CI, 1.39-2.79; P = 0.0001) (homozygous wild-type group) in men with prostate cancer when treated with ADT, however, a higher PFS (HR, 0.68; 95% CI, 0.48-0.96; P = 0.03) when treated with ADT and CYP17A1 inhibitor.

CONCLUSION

The HSD3B1 (1245C) variant is a predictor of ADT plus CYP17A1 inhibitor response in prostate cancer.

Germline HSD3B1 Genetics and Prostate Cancer Outcomes

Dihydrotestosterone synthesis in prostate cancer from adrenal DHEA/DHEA-sulfate requires enzymatic conversion in tumor tissues. 3β-hydroxysteroid dehydrogenase-1 is an absolutely necessary enzyme for such dihydrotestosterone synthesis and is encoded by the gene HSD3B1 which comes in 2 functional inherited forms described in 2013. The adrenal-permissive HSD3B1(1245C) allele allows for rapid dihydrotestosterone synthesis. The adrenal-restrictive HSD3B1(1245A) allele limits androgen synthesis. Studies from multiple cohorts show that adrenal-permissive allele inheritance confers worse outcomes and shorter survival after castration in low-volume prostate cancer and poor outcomes after abiraterone or enzalutamide treatment for castration-resistant prostate cancer. Here, we review the clinical data and implications.

Germline variants and response to systemic therapy in advanced prostate cancer

Our current understanding of prostate cancer pharmacogenomics is growing at a rapid pace. Apart from evaluating relevant biomarkers and genomic alterations in tumor tissues, an increasing focus is being placed on decoding the impact of germline alterations on prostate cancer and its treatment. Herein we summarize various germline variants that have shown to associate with response to systemic therapy in men with advanced prostate cancer. Covered biomarkers include HSD3B1, SLCO2B1, SULT1E1, TRMT11, CYP17A1, CYP1B1, genes involved in homologous recombination and DNA mismatch repair.

Through the Looking-Glass: Reevaluating DHEA Metabolism Through HSD3B1 Genetics

Dehydroepiandrosterone (DHEA) and DHEA sulfate together are abundant adrenal steroids whose physiological effects are mediated through their conversion to potent downstream androgens. 3β-Hydroxysteroid dehydrogenase isotype 1 (3βHSD1) facilitates the rate-limiting step of DHEA metabolism and gates the flux of substrate into the distal portion of the androgen synthesis pathway. Notably, a germline, missense-encoding change, HSD3B1(1245C), results in expression of 3βHSD1 protein that is resistant to degradation, yielding greater potent androgen production in the periphery. In contrast, HSD3B1(1245A) encodes 3βHSD1 protein that is easily degraded, limiting peripheral androgen synthesis. These adrenal-permissive (AP) and adrenal-restrictive (AR) alleles have recently been associated with divergent outcomes in androgen-sensitive disease states, underscoring the need to reevaluate DHEA metabolism using HSD3B1 genetics.

Examining HSD3B1 as a possible biomarker to detect prostate cancer patients who are likely to progress on ADT

The Chemohormonal Therapy vs Androgen Ablation Randomized Trial for Extensive Disease in Prostate Cancer (CHAARTED) was a randomized phase III trial that evaluated the outcomes of men with metastatic prostate cancer who received castration with or without docetaxel. Patients from this trial were genotyped in a recent study to detect HSD3B1 variance and to determine 2-y freedom from castration-resistant prostate cancer as well as overall survival. The results of this study identified HSD3B1 as a possible biomarker that can be used to predict response to therapy in patients with metastatic disease.

Dysregulated expression of androgen metabolism genes and genetic analysis in hypospadias

Background

The aberrant expression of genes involved in androgen metabolism and genetic contribution are unclear in hypospadias.

Methods

We compared gene expression profiles by RNA sequencing from five non‐hypospadiac foreskins, five mild hypospadiac foreskins, and five severe hypospadiac foreskins. In addition, to identify rare coding variants with large effects on hypospadias risk, we carried out whole exome sequencing in three patients in a hypospadias family.

Results

The average expression of androgen receptor (AR) and CYP19A1 were significantly decreased in severe hypospadias (p < .01) and mild hypospadias (p < .05), whereas expression of several other androgen metabolism enzymes, including CYP3A4, HSD17B14, HSD3B7, HSD17B7, CYP11A1 were exclusively significantly expressed in severe hypospadias (p < .05). Compound rare damaging mutants of AR gene with HSD3B1 and SLC25A5 genes were identified in the different severe hypospadias.

Conclusions

In conclusion, our findings demonstrated that dysregulation of AR and CYP19A1 could play a crucial role in the development of hypospadias. Inconsistent AR expression may be caused by the feedback loop of ESR1 signaling or combined genetic effects with other risk genes. This findings complement the possible role of AR triggered mechanism in the development of hypospadias.

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.

Treatment with abiraterone and enzalutamide does not overcome poor outcome from metastatic castration-resistant prostate cancer in men with the germline homozygous HSD3B1 c.1245C genotype

BACKGROUND

In men with castration-sensitive prostate cancer (CSPC), the HSD3B1 c.1245A>C variant has been reported to be associated with shorter responses to first-line androgen-deprivation therapy (ADT). Here, we evaluated the association between the inherited HSD3B1 c.1245A>C variant and outcomes from metastatic castration-resistant prostate cancer (mCRPC) after first-line treatment with abiraterone (Abi) or enzalutamide (Enza).

PATIENTS AND METHODS

Patients with mCRPC (n = 266) were enrolled from two centers at the time of starting first-line Abi/Enza. Outcomes after Abi/Enza included best prostate-specific antigen (PSA) response, treatment duration, and overall survival (OS). Outcomes after first-line ADT were determined retrospectively, and included treatment duration and OS. As was prespecified, we compared patients with the homozygous variant HSD3B1 genotype (CC genotype) versus the combined group with the heterozygous (AC) and homozygous wild-type (AA) genotypes.

RESULTS

Among the 266 patients, 22 (8.3%) were homozygous for the HSD3B1 variant (CC). The CC genotype had no association with PSA response rate; the median Abi/Enza treatment duration was 7.1 months for the CC group and 10.3 months for the AA/AC group (log rank P = 0.34). Patients with the CC genotype had significantly worse OS, with median survival at 23.6 months for the CC group and 30.7 months for the AA/AC group (log rank P = 0.02). In multivariable analysis adjusting for age, Gleason score, PSA, prior chemotherapy, and M1 disease, the association between the CC genotype and OS remained significant (hazard ratio 1.78, 95% confidence interval 1.03-3.07, P = 0.04). Poor outcome after first-line ADT in the CC group was also observed when evaluating retrospective ADT duration data for the same combined cohort.

CONCLUSIONS

In this large two-center study evaluating the HSD3B1 c.1245 genotype and outcomes after first-line Abi/Enza, homozygous variant (CC) HSD3B1 genotype was associated with worse outcomes. Novel therapeutic strategies are needed to enable treatment selection based on this genetic marker.

HSD3B1 Genotype and Clinical Outcomes in Metastatic Castration-Sensitive Prostate Cancer

Importance

The adrenal-restrictive HSD3B1(1245A) allele limits extragonadal dihydrotestosterone synthesis, whereas the adrenal-permissive HSD3B1(1245C) allele augments extragonadal dihydrotestosterone synthesis. Retrospective studies have suggested an association between the adrenal-permissive allele, the frequency of which is highest in white men, and early development of castration-resistant prostate cancer (CRPC).

Objective

To examine the association between the adrenal-permissive HSD3B1(1245C) allele and early development of CRPC using prospective data.

Design, Setting, and Participants

The E3805 Chemohormonal Therapy vs Androgen Ablation Randomized Trial for Extensive Disease in Prostate Cancer (CHAARTED) was a large, multicenter, phase 3 trial of castration with or without docetaxel treatment in men with newly diagnosed metastatic prostate cancer. From July 28, 2006, through December 31, 2012, 790 patients underwent randomization, of whom 527 had available DNA samples. In this study, the HSD3B1 germline genotype was retrospectively determined in 475 white men treated in E3805 CHAARTED, and clinical outcomes were analyzed by genotype. Data analysis was performed from July 28, 2006, to October 17, 2018.

Interventions

Men were randomized to castration plus docetaxel, 75 mg/m2, every 3 weeks for 6 cycles or castration alone.

Main Outcomes and Measures

Two-year freedom from CRPC and 5-year overall survival, with results stratified by disease volume. Patients were combined across study arms according to genotype to assess the overall outcome associated with genotype. Secondary analyses by treatment arm evaluated whether the docetaxel outcome varied with genotype.

Results

Of 475 white men with DNA samples, 270 patients (56.8%) inherited the adrenal-permissive genotype (≥1 HSD3B1[1245C] allele). Mean (SD) age was 63 (8.7) years. Freedom from CRPC at 2 years was diminished in men with low-volume disease with the adrenal-permissive vs adrenal-restrictive genotype: 51.0% (95% CI, 40.9%-61.2%) vs 70.5% (95% CI, 60.0%-80.9%) (P = .01). Overall survival at 5 years was also worse in men with low-volume disease with the adrenal-permissive genotype: 57.5% (95% CI, 47.4%-67.7%) vs 70.8% (95% CI, 60.3%-81.3%) (P = .03). Hazard ratios were 1.89 (95% CI, 1.13-3.14; P = .02) for CRPC and 1.74 (95% CI, 1.01-3.00; P = .045) for death. There was no association between genotype and outcomes in men with high-volume disease. There was no interaction between genotype and benefit from docetaxel.

Conclusions and Relevance

Inheritance of the adrenal-permissive HSD3B1 genotype is associated with earlier castration resistance and shorter overall survival in men with low-volume metastatic prostate cancer and may help identify men more likely to benefit from escalated androgen receptor axis inhibition beyond gonadal testosterone suppression.

The role of adrenal derived androgens in castration resistant prostate cancer

Castration resistant prostate cancer (CRPC) remains androgen dependant despite castrate levels of circulating testosterone following androgen deprivation therapy, the first line of treatment for advanced metstatic prostate cancer. CRPC is characterized by alterations in the expression levels of steroidgenic enzymes that enable the tumour to derive potent androgens from circulating adrenal androgen precursors. Intratumoral androgen biosynthesis leads to the localized production of both canonical androgens such as 5α-dihydrotestosterone (DHT) as well as less well characterized 11-oxygenated androgens, which until recently have been overlooked in the context of CRPC. In this review we discuss the contribution of both canonical and 11-oxygenated androgen precursors to the intratumoral androgen pool in CRPC. We present evidence that CRPC remains androgen dependent and discuss the alterations in steroidogenic enzyme expression and how these affect the various pathways to intratumoral androgen biosynthesis. Finally we summarize the current treatment strategies for targeting adrenal derived androgen biosynthesis.

HSD3B1 genotype identifies glucocorticoid responsiveness in severe asthma

Asthma resistance to glucocorticoid treatment is a major health problem with unclear etiology. Glucocorticoids inhibit adrenal androgen production. However, androgens have potential benefits in asthma. HSD3B1 encodes for 3β-hydroxysteroid dehydrogenase-1 (3β-HSD1), which catalyzes peripheral conversion from adrenal dehydroepiandrosterone (DHEA) to potent androgens and has a germline missense-encoding polymorphism. The adrenal restrictive HSD3B1(1245A) allele limits conversion, whereas the adrenal permissive HSD3B1(1245C) allele increases DHEA metabolism to potent androgens. In the Severe Asthma Research Program (SARP) III cohort, we determined the association between DHEA-sulfate and percentage predicted forced expiratory volume in 1 s (FEV1PP). HSD3B1(1245) genotypes were assessed, and association between adrenal restrictive and adrenal permissive alleles and FEV1PP in patients with (GC) and without (noGC) daily oral glucocorticoid treatment was determined (n = 318). Validation was performed in a second cohort (SARP I&II; n = 184). DHEA-sulfate is associated with FEV1PP and is suppressed with GC treatment. GC patients homozygous for the adrenal restrictive genotype have lower FEV1PP compared with noGC patients (54.3% vs. 75.1%; P < 0.001). In patients with the homozygous adrenal permissive genotype, there was no FEV1PP difference in GC vs. noGC patients (73.4% vs. 78.9%; P = 0.39). Results were independently confirmed: FEV1PP for homozygous adrenal restrictive genotype in GC vs. noGC is 49.8 vs. 63.4 (P < 0.001), and for homozygous adrenal permissive genotype, it is 66.7 vs. 67.7 (P = 0.92). The adrenal restrictive HSD3B1(1245) genotype is associated with GC resistance. This effect appears to be driven by GC suppression of 3β-HSD1 substrate. Our results suggest opportunities for prediction of GC resistance and pharmacologic intervention.

Sex Hormones and Prostate Cancer

The prostate is an androgen-dependent organ that develops only in male mammals. Prostate cancer is the most common nonskin malignancy in men and the second leading cause of cancer deaths. Metastatic prostate cancer initially retains its androgen dependence, and androgen-deprivation therapy often leads to disease control; however, the cancer inevitably progresses despite treatment as castration-resistant prostate cancer, the lethal form of the disease. Although it was assumed that the cancer became androgen independent during this transition, studies over the last two decades have shown that these tumors evade treatment via mechanisms that augment acquisition of androgens from circulating precursors, increase sensitivity to androgens and androgen precursors, bypass the androgen receptor, or a combination of these mechanisms. This review summarizes the history of prostate cancer research leading to the contemporary view of androgen dependence for prostate cancers and the current treatment approaches based on this modern paradigm.

The role of ketoconazole in current prostate cancer care

Ketoconazole is a nonselective steroid 17α-hydroxylase/17,20 lyase (CYP17A1) inhibitor that has been used, off-label, as a second-line therapy for castration-resistant prostate cancer (CRPC). The drug has shown clinical efficacy without survival benefit. Despite not improving survival, ketoconazole has beneficial characteristics, such as its low cost, a relatively favourable toxicity profile compared with chemotherapy, and its efficacy both before and after chemotherapy. The approval of several new, highly effective treatments, including abiraterone acetate, enzalutamide, and apalutamide, warrants re-evaluation of the role of ketoconazole and other classic agents in achieving the optimal timing and sequencing of available agents to prolong survival and maintain patients' quality of life. In the current CRPC treatment landscape, we believe that ketoconazole can be considered in patients with nonmetastatic CRPC and in those with metastatic CRPC who do not respond to, tolerate, or have access to chemotherapy and other standard therapeutic options.

HSD3B1 Genotypes Conferring Adrenal-Restrictive and Adrenal-Permissive Phenotypes in Prostate Cancer and Beyond

Castration-resistant prostate cancer (PCa) almost invariably occurs after androgen deprivation therapy for metastatic disease and is driven in part by androgen synthesis within the tumor. 3β-hydroxysteroid dehydrogenase isoenzyme-1 catalyzes the conversion of adrenal precursor steroids into potent androgens essential for PCa progression. A common 1245 A→C missense-encoding single nucleotide polymorphism in HSD3B1 (rs1047303), the gene that encodes this enzyme, leads to a more stable protein that is resistant to degradation and thus increased production of potent androgens from adrenal precursors, facilitating castration-resistant PCa development. Consistent with this mechanism, this adrenal-permissive HSD3B1(1245C) genotype is associated with inferior outcomes after androgen deprivation therapy for advanced PCa, and increased sensitivity to pharmacologic blockade of adrenal precursors in metastatic disease. Herein, we review current knowledge of the mechanisms conferred by HSD3B1 genotype to alter androgen physiology and accelerate development of castration-resistant disease and its associations with clinical PCa outcomes. In light of its effect on steroid physiology, we also discuss its potential associations with non-PCa phenotypes.

Targeting the androgen receptor and overcoming resistance in prostate cancer

PURPOSE OF REVIEW

Prostate cancer (PCa) is diagnosed in one out of every nine men and is the second leading cause of cancer death among men. Although therapies targeting the androgen receptor (AR) are highly effective, development of resistance is universal and remains a major therapeutic challenge. Nonetheless, signaling via AR is frequently maintained despite standard androgen-signaling inhibition. We review the current understanding of mechanisms of resistance as well as therapeutic approaches to improving treatment of PCa via targeting of the AR.

RECENT FINDINGS

Resistance to AR-targeting therapies may be mediated by several mechanisms, including amplification, mutation, and alternative splicing of AR; intratumoral androgen synthesis; activation of alternative signaling pathways; and in a minority of cases, emergence of AR-independent phenotypes. Recent trials demonstrate that intensification of androgen blockade in metastatic castration-sensitive PCa can significantly improve survival. Similar strategies are being explored in earlier disease states. In addition, several other cellular signaling pathways have been identified as mechanisms of resistance, offering opportunities for cotargeted therapy. Finally, immune-based approaches are in development to complement AR-targeted therapies.

SUMMARY

Targeting the AR remains a critical focus in the treatment of PCa.

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.

Canonical and Noncanonical Androgen Metabolism and Activity

Androgens are critical drivers of prostate cancer. In this chapter we first discuss the canonical pathways of androgen metabolism and their alterations in prostate cancer progression, including the classical, backdoor and 5α-dione pathways, the role of pre-receptor DHT metabolism, and recent findings on oncogenic splicing of steroidogenic enzymes. Next, we discuss the activity and metabolism of non-canonical 11-oxygenated androgens that can activate wild-type AR and are less susceptible to glucuronidation and inactivation than the canonical androgens, thereby serving as an under-recognized reservoir of active ligands. We then discuss an emerging literature on the potential non-canonical role of androgen metabolizing enzymes in driving prostate cancer. We conclude by discussing the potential implications of these findings for prostate cancer progression, particularly in context of new agents such as abiraterone and enzalutamide, which target the AR-axis for prostate cancer therapy, including mechanisms of response and resistance and implications of these findings for future therapy.

Functional Silencing of HSD17B2 in Prostate Cancer Promotes Disease Progression

PURPOSE

Steroidogenic enzymes are essential for prostate cancer development. Enzymes inactivating potent androgens were not investigated thoroughly, which leads to limited interference strategies for prostate cancer therapy. Here we characterized the clinical relevance, significance, and regulation mechanism of enzyme HSD17B2 in prostate cancer development.

EXPERIMENTAL DESIGN

HSD17B2 expression was detected with patient specimens and prostate cancer cell lines. Function of HSD17B2 in steroidogenesis, androgen receptor (AR) signaling, and tumor growth was investigated with prostate cancer cell lines and a xenograft model. DNA methylation and mRNA alternative splicing were investigated to unveil the mechanisms of HSD17B2 regulation.

RESULTS

HSD17B2 expression was reduced as prostate cancer progressed. 17βHSD2 decreased potent androgen production by converting testosterone (T) or dihydrotestosterone (DHT) to each of their upstream precursors. HSD17B2 overexpression suppressed androgen-induced cell proliferation and xenograft growth. Multiple mechanisms were involved in HSD17B2 functional silencing including DNA methylation and mRNA alternative splicing. DNA methylation decreased the HSD17B2 mRNA level. Two new catalytic-deficient isoforms, generated by alternative splicing, bound to wild-type 17βHSD2 and promoted its degradation. Splicing factors SRSF1 and SRSF5 participated in the generation of new isoforms.

CONCLUSIONS

Our findings provide evidence of the clinical relevance, significance, and regulation of HSD17B2 in prostate cancer progression, which might provide new strategies for clinical management by targeting the functional silencing mechanisms of HSD17B2.See related commentary by Mostaghel, p. 1139.

Unfavorable Pathology, Tissue Biomarkers and Genomic Tests With Clinical Implications in Prostate Cancer Management

Prostate cancer management has traditionally relied upon risk stratification of patients based on Gleason score, pretreatment prostate-specific antigen and clinical tumor stage. However, these factors alone do not adequately reflect the inherent complexity and heterogeneity of prostate cancer. Accurate and individualized risk stratification at the time of diagnosis is instrumental to facilitate clinical decision-making and treatment selection tailored to each patient. The incorporation of tissue and genetic biomarkers into current prostate cancer prediction models may optimize decision-making and improve patient outcomes. In this review we discuss the clinical significance of unfavorable morphologic features such as cribriform architecture and intraductal carcinoma of the prostate, tissue biomarkers and genomic tests and assess their potential use in prostate cancer risk assessment and treatment selection.

HSD3B1(1245A>C) variant regulates dueling abiraterone metabolite effects in prostate cancer

BACKGROUND

A common germline variant in HSD3B1(1245A>C) encodes for a hyperactive 3β-hydroxysteroid dehydrogenase 1 (3βHSD1) missense that increases metabolic flux from extragonadal precursor steroids to DHT synthesis in prostate cancer. Enabling of extragonadal DHT synthesis by HSD3B1(1245C) predicts for more rapid clinical resistance to castration and sensitivity to extragonadal androgen synthesis inhibition. HSD3B1(1245C) thus appears to define a subgroup of patients who benefit from blocking extragonadal androgens. However, abiraterone, which is administered to block extragonadal androgens, is a steroidal drug that is metabolized by 3βHSD1 to multiple steroidal metabolites, including 3-keto-5α-abiraterone, which stimulates the androgen receptor. Our objective was to determine if HSD3B1(1245C) inheritance is associated with increased 3-keto-5α-abiraterone synthesis in patients.

METHODS

First, we characterized the pharmacokinetics of 7 steroidal abiraterone metabolites in 15 healthy volunteers. Second, we determined the association between serum 3-keto-5α-abiraterone levels and HSD3B1 genotype in 30 patients treated with abiraterone acetate (AA) after correcting for the determined pharmacokinetics.

RESULTS

Patients who inherit 0, 1, and 2 copies of HSD3B1(1245C) have a stepwise increase in normalized 3-keto-5α-abiraterone (0.04 ng/ml, 2.60 ng/ml, and 2.70 ng/ml, respectively; P = 0.002).

CONCLUSION

Increased generation of 3-keto-5α-abiraterone in patients with HSD3B1(1245C) might partially negate abiraterone benefits in these patients who are otherwise more likely to benefit from CYP17A1 inhibition.

FUNDING

Prostate Cancer Foundation Challenge Award, National Cancer Institute.

AR Signaling in Prostate Cancer Regulates a Feed-Forward Mechanism of Androgen Synthesis by Way of HSD3B1 Upregulation

3βHSD1 enzymatic activity is essential for synthesis of potent androgens from adrenal precursor steroids in prostate cancer. A germline variant in HSD3B1, the gene that encodes 3βHSD1, encodes for a stable enzyme, regulates adrenal androgen dependence, and is a predictive biomarker of poor clinical outcomes after gonadal testosterone deprivation therapy. However, little is known about HSD3B1 transcriptional regulation. Generally, it is thought that intratumoral androgen synthesis is upregulated after gonadal testosterone deprivation, enabling development of castration-resistant prostate cancer. Given its critical role in extragonadal androgen synthesis, we sought to directly interrogate the transcriptional regulation of HSD3B1 in multiple metastatic prostate cancer cell models. Surprisingly, we found that VCaP, CWR22Rv1, LNCaP, and LAPC4 models demonstrate induction of HSD3B1 upon androgen stimulation for approximately 72 hours, followed by attenuation around 120 hours. 3βHSD1 protein levels mirrored transcriptional changes in models harboring variant (LNCaP) and wild-type (LAPC4) HSD3B1, and in these models androgen induction of HSD3B1 is abrogated via enzalutamide treatment. Androgen treatment increased flux from [3H]-dehydroepiandrosterone to androstenedione and other downstream metabolites. HSD3B1 expression was reduced 72 hours after castration in the VCaP xenograft mouse model, suggesting androgen receptor (AR) regulation of HSD3B1 also occurs in vivo. Overall, these data suggest that HSD3B1 is unexpectedly positively regulated by androgens and ARs. These data may have implications for the development of treatment strategies tailored to HSD3B1 genotype status.

Up regulation of the steroid hormone synthesis regulator HSD3B2 is linked to early PSA recurrence in prostate cancer

HSD3B2 plays a crucial role in steroid hormone biosynthesis and is thus of particular interest in hormone dependent tumors such as prostate cancer. To clarify the clinical relevance of HSD3B2 expression in prostate cancer, we analyzed HSD3B2 protein expression by immunohistochemistry on our preexisting tissue microarray with 12.247 annotated cancers. Compared with normal tissue cytoplasmic HSD3B2 staining was stronger in prostate cancers. In 9371 interpretable cancers, HSD3B2 expression was found in 95.5% of cancers and was considered weak in 29.9%, moderate in 40.7% and strong in 24.9%. HSD3B2 up regulation was linked to advanced pathological tumor stage (pT), high Gleason grade, elevated preoperative PSA levels (p < 0.0001 each), lymph node metastasis (p = 0.0019), accelerated cell proliferation (p < 0.0001), androgen receptor (AR) expression (p < 0.0001), and early biochemical recurrence (p < 0.0001). HSD3B2 up regulation was only marginally more frequent in ERG positive (98%) than in ERG negative cancers (94%; p < 0.0001) and was strongly linked to deletions of 5q and 6q (p < 0.0001 each). Multivariate analyses showed that the prognostic impact of HSD3B2 expression was independent of established preoperative, but not of postoperative prognostic parameters. In summary, the results of our study demonstrate that HSD3B2 is strongly up regulated in a fraction of prostate cancers that are characterized by increased AR signaling, adverse tumor phenotype and early biochemical recurrence.

Value-based genomics

Advancements in next-generation sequencing have greatly enhanced the development of biomarker-driven cancer therapies. The affordability and availability of next-generation sequencers have allowed for the commercialization of next-generation sequencing platforms that have found widespread use for clinical-decision making and research purposes. Despite the greater availability of tumor molecular profiling by next-generation sequencing at our doorsteps, the achievement of value-based care, or improving patient outcomes while reducing overall costs or risks, in the era of precision oncology remains a looming challenge. In this review, we highlight available data through a pre-established and conceptualized framework for evaluating value-based medicine to assess the cost (efficiency), clinical benefit (effectiveness), and toxicity (safety) of genomic profiling in cancer care. We also provide perspectives on future directions of next-generation sequencing from targeted panels to whole-exome or whole-genome sequencing and describe potential strategies needed to attain value-based genomics.

Loss of an Androgen-Inactivating and Isoform-Specific HSD17B4 Splice Form Enables Emergence of Castration-Resistant Prostate Cancer

Castration-resistant prostate cancer (CRPC) requires tumors to engage metabolic mechanisms that allow sustained testosterone and/or dihydrotestosterone to stimulate progression. 17β-Hydroxysteroid dehydrogenase type 4 (17βHSD4), encoded by HSD17B4, is thought to inactivate testosterone and dihydrotestosterone by converting them to their respective inert 17-keto steroids. Counterintuitively, HSD17B4 expression increases in CRPC and predicts poor prognosis. Here, we show that, of five alternative splice forms, only isoform 2 encodes an enzyme capable of testosterone and dihydrotestosterone inactivation. In contrast with other transcripts, functional expression of isoform 2 is specifically suppressed in development of CRPC in patients. Genetically silencing isoform 2 shifts the metabolic balance toward 17β-OH androgens (testosterone and dihydrotestosterone), stimulating androgen receptor (AR) and CRPC development. Our studies specifically implicate HSD17B4 isoform 2 loss in lethal prostate cancer.

HSD3B1 status as a biomarker of androgen deprivation resistance and implications for prostate cancer

Patients with advanced prostate cancer who receive androgen deprivation therapy (ADT) almost invariably develop castration-resistant disease. The mechanism of resistance is largely based on synthesis of intratumoral androgens from adrenal precursors, requiring enzymatic action of 3β-hydroxysteroid dehydrogenase/Δ^5→4 isomerase 1 (3β-HSD1), encoded by HSD3B1. A nucleotide polymorphism (1245A>C) in HSD3B1 results in a protein variant with increased steady-state levels and subsequently increased androgen synthesis from extragonadal precursors. Multiple clinical studies have shown that patients with the variant allele have significantly worse outcomes after ADT than those without, indicating that HSD3B1 variant status is a predictive biomarker of shortened ADT response. In addition, inheritance of the HSD3B1 variant is associated with extended responses to 17α-hydroxylase/17,20-lyase (CYP17A1) inhibition with a nonsteroidal agent, adding to evidence of increased tumour dependence on extragonadal androgens in patients who inherited the HSD3B1 variant. However, steroidal drugs with a 3β-hydroxyl, Δ⁵-structure, such as abiraterone, are also metabolized by 3β-HSD1, and 5α-abiraterone, a downstream metabolite, has been shown to activate the androgen receptor, potentially driving cancer progression. These data indicate a potential requirement to modify the treatment framework of patients harbouring variant HSD3B1.