Distinct patterns of dysregulated expression of enzymes involved in androgen synthesis and metabolism in metastatic prostate cancer tumors

The miRNAs 203a/210-3p/5001-5p regulate the androgen/androgen receptor/YAP-induced migration in prostate cancer cells

BACKGROUND

Prostate cancer (PCa) patients with elevated level of androgen receptor (AR) correlate with higher metastatic incidence. Protein expression of AR and its target gene prostate-specific antigen (PSA) are elevated in metastatic prostate tumors as compared to organ-confined tumors. Androgen treatment or elevation of AR promotes metastasis of PCa in cell culture and murine model. However, under androgen depleted condition, AR suppressed cell mobility and invasiveness of PCa cells. Androgen deprivation therapy in PCa patients is associated with higher risk of cancer metastasis. We therefore investigated the dual roles of AR and miRNAs on PCa metastasis.

METHODS

The PC-3AR (PC-3 cells re-expressing AR) and LNCaP cells were used as PCa cell model. Transwell migration and invasion assay, wound-healing assay, zebrafish xenotransplantation assay, and zebrafish vascular exit assay were used to investigate the role of AR and androgen on PCa metastasis. Micro-Western Array, co-immunoprecipitation and Immunofluorescence were applied to dissect the molecular mechanism lying underneath. The miRNA array, miRNA inhibitors or plasmid, and chromatin immunoprecipitation assay were used to study the role of miRNAs on PCa metastasis.

RESULTS

In the absence of androgen, AR repressed the migration and invasion of PCa cells. When androgen was present, AR stimulated the migration and invasion of PCa cells both in vitro and in zebrafish xenotransplantation model. Androgen increased phospho-AR Ser81 and yes-associated protein 1 (YAP), decreased phospho-YAP Ser217, and altered epithelial-mesenchymal transition (EMT) proteins in PCa cells. Co-IP assay demonstrated that androgen augmented the interaction between YAP and AR in nucleus. Knockdown of YAP or treatment with YAP inhibitor abolished the androgen-induced migration and invasion of PCa cells, while overexpression of YAP showed opposite effects. The miRNA array revealed that androgen decreased hsa-miR-5001-5p but increased hsa-miR-203a and hsa-miR-210-3p in PC-3AR cells but not PC-3 cells. Treatment with inhibitors targeting hsa-miR-203a/hsa-miR-210-3p, or overexpression of hsa-miR-5001-5p decreased YAP expression as well as suppressed the androgen-induced migration and invasion of PCa cells. Chromatin immunoprecipitation (ChIP) assay demonstrated that AR binds with promoter region of has-miR-210-3p in the presence of androgen.

CONCLUSIONS

Our observations indicated that miRNAs 203a/210-3p/5001-5p regulate the androgen/AR/YAP-induced PCa metastasis.

Aldo-keto reductases: Role in cancer development and theranostics

Aldo-keto reductases (AKRs) are a superfamily of enzymes that play crucial roles in various cellular processes, including the metabolism of xenobiotics, steroids, and carbohydrates. A growing body of evidence has unveiled the involvement of AKRs in the development and progression of various cancers. AKRs are aberrantly expressed in a wide range of malignant tumors. Dysregulated expression of AKRs enables the acquisition of hallmark traits of cancer by activating oncogenic signaling pathways and contributing to chemoresistance. AKRs have emerged as promising oncotherapeutic targets given their pivotal role in cancer development and progression. Inhibition of aldose reductase (AR), either alone or in combination with chemotherapeutic drugs, has evolved as a pragmatic therapeutic option for cancer. Several classes of synthetic aldo-keto reductase (AKR) inhibitors have been developed as potential anticancer agents, some of which have shown promise in clinical trials. Many AKR inhibitors from natural sources also exhibit anticancer effects. Small molecule inhibitors targeting specific AKR isoforms have shown promise in preclinical studies. These inhibitors disrupt the activation of oncogenic signaling by modulating transcription factors and kinases and sensitizing cancer cells to chemotherapy. In this review, we discuss the physiological functions of human AKRs, the aberrant expression of AKRs in malignancies, the involvement of AKRs in the acquisition of cancer hallmarks, and the role of AKRs in oncogenic signaling, and drug resistance. Finally, the potential of aldose reductase inhibitors (ARIs) as anticancer drugs is summarized.

Pregnane X receptor (PXR) deficiency promotes hepatocarcinogenesis via induction of Akr1c18 expression and prostaglandin F2α (PGF2α) levels

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. Pregnane X receptor (PXR), a xenobiotic-sensing nuclear receptor, plays a critical role in the metabolism of endogenous and exogenous substances in the liver. Here, we investigate whether PXR plays a role in pathogenesis of HCC. We show that liver tumors were developed in diethylnitrosamine (DEN)-treated in PXR knockout (KO) mice. Hepatic levels of prostaglandin F2α (PGF2α) and aldo-keto reductase family 1 member C18 (Akr1c18), a prostaglandin synthase of catalyzing reduction of PGH2 to PGF2α, were significantly elevated in DEN-treated PXR KO mice. Hepatic mRNA levels of alpha fetoprotein (AFP), cyclin D1 (Ccnd1), fibroblast growth factor 21 (FGF21), and inflammatory cytokine interleukin 6 (IL-6) were significantly increased in DEN-treated PXR KO mice. Other members of Akr1c family, liver metabolizing enzymes including Cyp1a2, Cyp2b10 and Cyp3a11, and bile acid synthesis enzyme Cyp7a1 mRNA levels were significantly decreased in DEN-treated PXR KO mice. Our findings revealed that PXR deficiency promoted DEN-induced HCC in mice via induction of Akr1c18 expression and PGF2α levels and the increased PGF2α levels synthetized by Akr1c18 enhanced hepatocytes proliferation and induced inflammatory cytokine production, which accelerated liver tumor development after DEN treatment, suggesting that PXR deficiency may create a microenvironment that is more prone to DEN-induced liver tumors and targeting PXR and Akr1c18 to reduce PGF2α biosynthesis may be a potential and novel therapeutic strategy for HCC.

DHODH inhibition represents a therapeutic strategy and improves abiraterone treatment in castration-resistant prostate cancer

Castration-resistant prostate cancer (CRPC) is an aggressive disease with poor prognosis, and there is an urgent need for more effective therapeutic targets to address this challenge. Here, we showed that dihydroorotate dehydrogenase (DHODH), an enzyme crucial in the pyrimidine biosynthesis pathway, is a promising therapeutic target for CRPC. The transcript levels of DHODH were significantly elevated in prostate tumors and were negatively correlated with the prognosis of patients with prostate cancer. DHODH inhibition effectively suppressed CRPC progression by blocking cell cycle progression and inducing apoptosis. Notably, treatment with DHODH inhibitor BAY2402234 activated androgen biosynthesis signaling in CRPC cells. However, the combination treatment with BAY2402234 and abiraterone decreased intratumoral testosterone levels and induced apoptosis, which inhibited the growth of CWR22Rv1 xenograft tumors and patient-derived xenograft organoids. Taken together, these results establish DHODH as a key player in CRPC and as a potential therapeutic target for advanced prostate cancer.

Genetically predicted serum testosterone and risk of gynecological disorders: a Mendelian randomization study

Background

Testosterone plays a key role in women, but the associations of serum testosterone level with gynecological disorders risk are inconclusive in observational studies.

Methods

We leveraged public genome-wide association studies to analyze the effects of four testosterone related exposure factors on nine gynecological diseases. Causal estimates were calculated by inverse variance-weighted (IVW), MR-Egger and weighted median methods. The heterogeneity test was performed on the obtained data through Cochrane's Q value, and the horizontal pleiotropy test was performed on the data through MR-Egger intercept and MR-PRESSO methods. "mRnd" online analysis tool was used to evaluate the statistical power of MR estimates.

Results

The results showed that total testosterone and bioavailable testosterone were protective factors for ovarian cancer (odds ratio (OR) = 0.885, P = 0.012; OR = 0.871, P = 0.005) and endometriosis (OR = 0.805, P = 0.020; OR = 0.842, P = 0.028) but were risk factors for endometrial cancer (OR = 1.549, P < 0.001; OR = 1.499, P < 0.001) and polycystic ovary syndrome (PCOS) (OR = 1.606, P = 0.019; OR = 1.637, P = 0.017). dehydroepiandrosterone sulfate (DHEAS) is a protective factor against endometriosis (OR = 0.840, P = 0.016) and premature ovarian failure (POF) (OR = 0.461, P = 0.046) and a risk factor for endometrial cancer (OR= 1.788, P < 0.001) and PCOS (OR= 1.970, P = 0.014). sex hormone-binding globulin (SHBG) is a protective factor against endometrial cancer (OR = 0.823, P < 0.001) and PCOS (OR = 0.715, P = 0.031).

Conclusion

Our analysis suggested causal associations between serum testosterone level and ovarian cancer, endometrial cancer, endometriosis, PCOS, POF.

AKR1C3 Converts Castrate and Post-Abiraterone DHEA-S into Testosterone to Stimulate Growth of Prostate Cancer Cells via 5-Androstene-3β,17β-Diol

Androgen receptor signaling inhibitors (ARSI) are used to treat castration-resistant prostate cancer (CRPC) to stop a resurgence of androgen receptor (AR) signaling. Despite early success, patients on ARSIs eventually relapse, develop drug resistance, and succumb to the disease. Resistance may occur through intratumoral steroidogenesis mediated by upregulation of aldo-keto reductase family 1C member 3 (AKR1C3). Patients treated with leuprolide (castrate) and those treated with leuprolide plus abiraterone (post-Abi) harbor a reservoir of DHEA-S which could fuel testosterone (T) biosynthesis via AKR1C3 to cause a resurgence of prostate cancer cell growth. We demonstrate that concentrations of DHEA-S found in castrate and post-Abi patients are (i) converted to T in an AKR1C3-dependent manner in prostate cancer cells, and (ii) in amounts sufficient to stimulate AKR1C3-dependent cell growth. We observed this in primary and metastatic prostate cancer cell lines, CWR22PC and DuCaP, respectively. Androgen measurements were made by stable isotope dilution LC-MS/MS. We demonstrate AKR1C3 dependence using stable short hairpin RNA knockdown and pharmacologic inhibitors. We also demonstrate that free DHEA is reduced to 5-androstene-3β,17β-diol (5-Adiol) by AKR1C3 and that this is a major metabolite, suggesting that in our cell lines 5-Adiol is a predominant precursor of T. We have identified a mechanism of ARSI resistance common to both primary and metastatic cell lines that is dependent on the conversion of DHEA to 5-Adiol on route to T catalyzed by AKR1C3.

SIGNIFICANCE

We show that reservoirs of DHEA-S that remain after ARSI treatment are converted into T in primary and metastatic prostate cancer cells in amounts sufficient to stimulate cell growth. Pharmacologic and genetic approaches demonstrate that AKR1C3 is required for these effects. Furthermore, the route to T proceeds through 5-Adiol. We propose that this is a mechanism of ARSI drug resistance.

Targeting the Androgen Signaling Axis in Prostate Cancer

Activation of the androgen receptor (AR) and AR-driven transcriptional programs is central to the pathophysiology of prostate cancer. Despite successful translational efforts in targeting AR, therapeutic resistance often occurs as a result of molecular alterations in the androgen signaling axis. The efficacy of next-generation AR-directed therapies for castration-resistant prostate cancer has provided crucial clinical validation for the continued dependence on AR signaling and introduced a range of new treatment options for men with both castration-resistant and castration-sensitive disease. Despite this, however, metastatic prostate cancer largely remains an incurable disease, highlighting the need to better understand the diverse mechanisms by which tumors thwart AR-directed therapies, which may inform new therapeutic avenues. In this review, we revisit concepts in AR signaling and current understandings of AR signaling-dependent resistance mechanisms as well as the next frontier of AR targeting in prostate cancer.

Novel inhibition of AKR1C3 and androgen receptor axis by PTUPB synergizes enzalutamide treatment in advanced prostate cancer

Castration-resistant prostate cancer (CRPC) is the main driving force of mortality in prostate cancer patients. Among the parameters contributing to the progression of CRPC and treatment failure, elevation of the steroidogenic enzyme AKR1C3 and androgen receptor variant 7 (AR-V7) are frequently reported. The AKR1C3/AR-V7 complex has been recognized as a major driver for drug resistance in advanced prostate cancer. Herein we report that the level of AKR1C3 is reciprocally regulated by the full-length androgen receptor (AR-FL) through binding to the distal enhancer region of the AKR1C3 gene. A novel function of PTUPB in AKR1C3 inhibition was discovered and PTUPB showed more effectiveness than indomethacin and celecoxib in suppressing AKR1C3 activity and CRPC cell growth. PTUPB synergizes with enzalutamide treatment in tumor suppression and gene signature regulation. Combination treatments with PTUPB and enzalutamide provide benefits by blocking AR/AR-V7 signaling, which inhibits the growth of castration relapsed VCaP xenograft tumors and patient-derived xenograft organoids. Targeting of the ARK1C3/AR/AR-V7 axis with PTUPB and enzalutamide may overcome drug resistance to AR signaling inhibitors in advanced prostate cancer.

The role of 11-oxygenated androgens in prostate cancer

11-oxygenated androgens are a class of steroids capable of activating the androgen receptor (AR) at physiologically relevant concentrations. In view of the AR as a key driver of prostate cancer (PC), these steroids are potential drivers of disease and progression. The 11-oxygenated androgens are adrenal-derived, and persist after androgen deprivation therapy (ADT), the mainstay treatment for advanced PC. Consequently, these steroids are of particular interest in the castration-resistant prostate cancer (CRPC) setting. The principal androgen of the pathway, 11-ketotestosterone (11KT), is a potent AR agonist and the predominant circulating active androgen in CRPC patients. Additionally, several precursor steroids are present in the circulation which can be converted into active androgens by steroidogenic enzymes present in PC cells. In vitro evidence suggests that adaptations frequently observed in CRPC favour the intratumoral accumulation of 11-oxygenated androgens in particular. Still, apparent gaps in our understanding of the physiology and role of the 11-oxygenated androgens remain. In particular, in vivo and clinical evidence supporting these in vitro findings is limited. Despite recent advances, a comprehensive assessment of intratumoral concentrations has not yet been performed. The exact contribution of the 11-oxygenated androgens to CRPC progression therefore remains unclear. This review will focus on the current evidence linking the 11-oxygenated androgens to PC, will highlight current gaps in our knowledge, and will provide insight into the potential clinical importance of the 11-oxygenated androgens in the CRPC setting based on the current evidence.

The prognosis of lipid reprogramming with the HMG-CoA reductase inhibitor, rosuvastatin, in castrated Egyptian prostate cancer patients: Randomized trial

AIM

The role of surgical castration and rosuvastatin treatment on lipid profile and lipid metabolism related markers was evaluated for their prognostic significance in metastatic prostate cancer (mPC) patients.

METHODS

A total of 84 newly diagnosed castrated mPC patients treated with castration were recruited and divided into two groups: Group I served as control (statin non-users) while group II treated with Rosuvastatin (20 mg/day) for 6 months and served as statin users. Prostate specific antigen (PSA), epidermal growth factor receptor (EGFR), Caveolin-1 (CAV1), lipid profile (LDL, HDL, triglycerides (TG) and total cholesterol (TC)) and lipid metabolism related markers (aldoketoreductase (AKR1C4), HMG-CoA reductase (HMGCR), ATP-binding cassette transporter A1 (ABCA1), and soluble low density lipoprotein receptor related protein 1 (SLDLRP1)) were measured at baseline, after 3 and 6 months. Overall survival (OS) was analyzed by Kaplan-Meier and COX regression for prognostic significance.

RESULTS

Before castration, HMG-CoA reductase was elevated in patients <65 years (P = 0.009). Bone metastasis was associated with high PSA level (P = 0.013), but low HMGCR (P = 0.004). Patients with positive family history for prostate cancer showed high levels of EGFR, TG, TC, LDL, alkaline phosphatase (ALP), but low AKR1C4, SLDLRP1, CAV1 and ABCA-1 levels. Smokers had high CAV1 level (P = 0.017). After 6 months of castration and rosuvastatin administration, PSA, TG, LDL and TC were significantly reduced, while AKR1C4, HMGCR, SLDLRP1, CAV1 and ABCA-1 were significantly increased. Overall survival was reduced in patients with high baseline of SLDLRP1 (>3385 pg/ml, P = 0.001), PSA (>40 ng/ml, P = 0.003) and CAV1 (>4955 pg/ml, P = 0.021).

CONCLUSION

Results of the current study suggest that the peripheral lipidogenic effects of rosuvastatin may have an impact on the treatment outcome and survival of castrated mPC patients.

TRAIL REGISTRATION

This trial was registered at the Pan African Clinical Trial Registry with identification number PACTR202102664354163 and at ClinicalTrials.gov with identification number NCT04776889.

First-in-Class Small Molecule to Inhibit CYP11A1 and Steroid Hormone Biosynthesis

Binding of steroid hormones to their cognate receptors regulates the growth of most prostate and breast cancers. We hypothesized that CYP11A inhibition might halt the synthesis of all steroid hormones, because CYP11A is the only enzyme that catalyses the first step of steroid hormone biosynthesis. We speculated that a CYP11A inhibitor could be administered safely provided that the steroids essential for life are replaced. Virtual screening and systematic structure-activity relationship optimization were used to develop ODM-208, the first-in-class, selective, nonsteroidal, oral CYP11A1 inhibitor. Safety of ODM-208 was assessed in rats and Beagle dogs, and efficacy in a VCaP castration-resistant prostate cancer (CRPC) xenograft mouse model, in mice and dogs, and in six patients with metastatic CRPC. Blood steroid hormone concentrations were measured using liquid chromatography-mass spectrometry. ODM-208 binds to CYP11A1 and inhibited its enzymatic activity. ODM-208 administration led to rapid, complete, durable, and reversible inhibition of the steroid hormone biosynthesis in an adrenocortical carcinoma cell model in vitro, in adult noncastrated male mice and dogs, and in patients with CRPC. All measured serum steroid hormone concentrations reached undetectable levels within a few weeks from the start of ODM-208 administration. ODM-208 was well tolerated with steroid hormone replacement. The toxicity findings were considered related to CYP11A1 inhibition and were reversed after stopping of the compound administration. Steroid hormone biosynthesis can be effectively inhibited with a small-molecule inhibitor of CYP11A1. The findings suggest that administration of ODM-208 is feasible with concomitant corticosteroid replacement therapy.

A novel prognostic model for prostate cancer based on androgen biosynthetic and catabolic pathways

Prostate cancer (PCa) is one of the most common malignancies in males globally, and its pathogenesis is significantly related to androgen. As one of the important treatments for prostate cancer, androgen deprivation therapy (ADT) inhibits tumor proliferation by controlling androgen levels, either surgically or pharmacologically. However, patients treated with ADT inevitably develop biochemical recurrence and advance to castration-resistant prostate cancer which has been reported to be associated with androgen biosynthetic and catabolic pathways. Thus, gene expression profiles and clinical information of PCa patients were collected from TCGA, MSKCC, and GEO databases for consensus clustering based on androgen biosynthetic and catabolic pathways. Subsequently, a novel prognostic model containing 13 genes (AFF3, B4GALNT4, CD38, CHRNA2, CST2, ADGRF5, KLK14, LRRC31, MT1F, MT1G, SFTPA2, SLC7A4, TDRD1) was constructed by univariate cox regression, lasso regression, and multivariate cox regression. Patients were divided into two groups based on their risk scores: high risk (HS) and low risk (LS), and survival analysis was used to determine the difference in biochemical recurrence-free time between the two. The results were validated on the MSKCC dataset and the GEO dataset. Functional enrichment analysis revealed some pivotal pathways that may have an impact on the prognosis of patients including the CDK-RB-E2F axis, G2M checkpoint, and KRAS signaling. In addition, somatic mutation, immune infiltration, and drug sensitivity analyses were performed to further explore the characteristics of HS and LS groups. Besides, two potential therapeutic targets, BIRC5 and RHOC, were identified by us in prostate cancer. These results indicate that the prognostic model may serve as a predictive tool to guide clinical treatment and provide new insight into the basic research in prostate cancer.

Androgen Metabolism and Response in Prostate Cancer Anti-Androgen Therapy Resistance

All aspects of prostate cancer evolution are closely related to androgen levels and the status of the androgen receptor (AR). Almost all treatments target androgen metabolism pathways and AR, from castration-sensitive prostate cancer (CSPC) to castration-resistant prostate cancer (CRPC). Alterations in androgen metabolism and its response are one of the main reasons for prostate cancer drug resistance. In this review, we will introduce androgen metabolism, including how the androgen was synthesized, consumed, and responded to in healthy people and prostate cancer patients, and discuss how these alterations in androgen metabolism contribute to the resistance to anti-androgen therapy.

Plasma Exosomal AKR1C3 mRNA Expression Is a Predictive and Prognostic Biomarker in Patients with Metastatic Castration-Resistant Prostate Cancer

PURPOSE

Aldo-keto reductase family 1 member C3 (AKR1C3) is important in prostate cancer progression, being a potential biomarker in metastatic castration-resistant prostate cancer (mCRPC). Previous explorations of AKR1C3 are mainly based on tissue samples. This study investigates using plasma-based liquid biopsy to validate the prognostic and predictive value of AKR1C3 in patients with mCRPC .

MATERIALS AND METHODS

We prospectively recruited 62 patients with mCRPC. All patients received repeated prostate biopsies at the time of mCRPC diagnosis, and immunohistochemistry (IHC) staining was used to detect protein expression of AKR1C3 in the tissues. We took their blood simultaneously and performed digital droplet polymerase chain reaction (ddPCR) to measure expression levels of AKR1C3 in the exosomes. The detected plasma and tissue AKR1C3 expression levels were analyzed for patients' overall survival (OS) and progression-free survival under first-line abiraterone use (ABI-PFS).

RESULTS

All other baseline characteristics were balanced between the 2 groups. 15/62 (24.2%) and 25/62 (40.3%) patients showed AKR1C3-EXO positive (≥20 copies/20 μL) and AKR1C3-IHC positive, respectively. Positive AKR1C3-EXO expression was associated with decreased patients' survival [ABI-PFS: 3.9 vs 10.1 months, P < .001; OS: 16.2 vs 32.5 months, P < .001]. AKR1C3-IHC positivity was also correlated with ABI-PFS and OS (P = .010, P = .016). In patients with worse baseline blood tests (including higher alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) level and lower hemoglobin (HB) level), and lower ISUP/WHO group (<4), their OS was significantly worse when showing AKR1C3-EXO positive.

CONCLUSION

AKR1C3-EXO is associated with patient prognosis regarding OS and ABI-PFS and can be used as a biomarker in mCRPC.

From Omics to Multi-Omics Approaches for In-Depth Analysis of the Molecular Mechanisms of Prostate Cancer

Cancer arises following alterations at different cellular levels, including genetic and epigenetic modifications, transcription and translation dysregulation, as well as metabolic variations. High-throughput omics technologies that allow one to identify and quantify processes involved in these changes are now available and have been instrumental in generating a wealth of steadily increasing data from patient tumors, liquid biopsies, and from tumor models. Extensive investigation and integration of these data have led to new biological insights into the origin and development of multiple cancer types and helped to unravel the molecular networks underlying this complex pathology. The comprehensive and quantitative analysis of a molecule class in a biological sample is named omics and large-scale omics studies addressing different prostate cancer stages have been performed in recent years. Prostate tumors represent the second leading cancer type and a prevalent cause of cancer death in men worldwide. It is a very heterogenous disease so that evaluating inter- and intra-tumor differences will be essential for a precise insight into disease development and plasticity, but also for the development of personalized therapies. There is ample evidence for the key role of the androgen receptor, a steroid hormone-activated transcription factor, in driving early and late stages of the disease, and this led to the development and approval of drugs addressing diverse targets along this pathway. Early genomic and transcriptomic studies have allowed one to determine the genes involved in prostate cancer and regulated by androgen signaling or other tumor-relevant signaling pathways. More recently, they have been supplemented by epigenomic, cistromic, proteomic and metabolomic analyses, thus, increasing our knowledge on the intricate mechanisms involved, the various levels of regulation and their interplay. The comprehensive investigation of these omics approaches and their integration into multi-omics analyses have led to a much deeper understanding of the molecular pathways involved in prostate cancer progression, and in response and resistance to therapies. This brings the hope that novel vulnerabilities will be identified, that existing therapies will be more beneficial by targeting the patient population likely to respond best, and that bespoke treatments with increased efficacy will be available soon.

Stimulus-responsive self-assembled prodrugs in cancer therapy

Small-molecule prodrugs have become the main toolbox to improve the unfavorable physicochemical properties of potential therapeutic compounds in contemporary anti-cancer drug development. Many approved small-molecule prodrugs, however, still face key challenges in their pharmacokinetic (PK) and pharmacodynamic (PD) properties, thus severely restricting their further clinical applications. Self-assembled prodrugs thus emerged as they could take advantage of key benefits in both prodrug design and nanomedicine, so as to maximize drug loading, reduce premature leakage, and improve PK/PD parameters and targeting ability. Notably, temporally and spatially controlled release of drugs at cancerous sites could be achieved by encoding various activable linkers that are sensitive to chemical or biological stimuli in the tumor microenvironment (TME). In this review, we have comprehensively summarized the recent progress made in the development of single/multiple-stimulus-responsive self-assembled prodrugs for mono- and combinatorial therapy. A special focus was placed on various prodrug conjugation strategies (polymer-drug conjugates, drug-drug conjugates, etc.) that facilitated the engineering of self-assembled prodrugs, and various linker chemistries that enabled selective controlled release of active drugs at tumor sites. Furthermore, some polymeric nano-prodrugs that entered clinical trials have also been elaborated here. Finally, we have discussed the bottlenecks in the field of prodrug nanoassembly and offered potential solutions to overcome them. We believe that this review will provide a comprehensive reference for the rational design of effective prodrug nanoassemblies that have clinic translation potential.

Circulating tumor cell gene expression and plasma AR gene copy number as biomarkers for castration-resistant prostate cancer patients treated with cabazitaxel

BACKGROUND

Cabazitaxel improves overall survival (OS) in metastatic castration-resistant prostate cancer (mCRPC) patients progressing after docetaxel. In this prospective study, we evaluated the prognostic role of CTC gene expression on cabazitaxel-treated patients and its association with plasma androgen receptor (AR) copy number (CN).

METHODS

Patients receiving cabazitaxel 20 or 25 mg/sqm for mCRPC were enrolled. Digital PCR was performed to assess plasma AR CN status. CTC enrichment was assessed using the AdnaTest EMT-2/StemCell kit. CTC expression analyses were performed for 17 genes. Data are expressed as hazard ratio (HR) or odds ratio (OR) and 95% CI.

RESULTS

Seventy-four patients were fully evaluable. CTC expression of AR-V7 (HR=2.52, 1.24-5.12, p=0.011), AKR1C3 (HR=2.01, 1.06-3.81, p=0.031), AR (HR=2.70, 1.46-5.01, p=0.002), EPCAM (HR=3.75, 2.10-6.71, p< 0.0001), PSMA (HR=2.09, 1.19-3.66, p=0.01), MDK (HR=3.35, 1.83-6.13, p< 0.0001), and HPRT1 (HR=2.46, 1.44-4.18, p=0.0009) was significantly associated with OS. ALDH1 (OR=5.50, 0.97-31.22, p=0.05), AR (OR=8.71, 2.32-32.25, p=0.001), EPCAM (OR=7.26, 1.47-35.73, p=0.015), PSMA (OR=3.86, 1.10-13.50, p=0.035), MDK (OR=6.84, 1.87-24.98, p=0.004), and HPRT1 (OR=7.41, 1.82-30.19, p=0.005) expression was associated with early PD. AR CN status was significantly correlated with AR-V7 (p=0.05), EPCAM (p=0.02), and MDK (p=0.002) expression. In multivariable model, EPCAM and HPRT1 CTC expression, plasma AR CN gain, ECOG PS=2, and liver metastases and PSA were independently associated with poorer OS. In patients treated with cabazitaxel 20 mg/sqm, median OS was shorter in AR-V7 positive than negative patients (6.6 versus 14 months, HR=3.46, 1.47-8.17], p=0.004).

CONCLUSIONS

Baseline CTC biomarkers may be prognosticators for cabazitaxel-treated mCRPC patients. Cabazitaxel at lower (20 mg/sqm) dose was associated with poorer outcomes in AR-V7 positive patients compared to AR-V7 negative patients in a post hoc subgroup analysis.

TRIAL REGISTRATION

Clinicaltrials.gov NCT03381326 . Retrospectively registered on 18 December 2017.

Androgen Receptor Signaling in Prostate Cancer and Therapeutic Strategies

Understanding of the molecular mechanisms of prostate cancer has led to development of therapeutic strategies targeting androgen receptor (AR). These androgen-receptor signaling inhibitors (ARSI) include androgen synthesis inhibitor-abiraterone and androgen receptor antagonists-enzalutamide, apalutamide, and darolutamide. Although these medications provide significant improvement in survival among men with prostate cancer, drug resistance develops in nearly all patients with time. This could be through androgen-dependent or androgen-independent mechanisms. Even weaker signals and non-canonical steroid ligands can activate AR in the presence of truncated AR-splice variants, AR overexpression, or activating mutations in AR. AR splice variant, AR-V7 is the most studied among these and is not targeted by available ARSIs. Non-androgen receptor dependent resistance mechanisms are mediated by activation of an alternative signaling pathway when AR is inhibited. DNA repair pathway, PI3K/AKT/mTOR pathway, BRAF-MAPK and Wnt signaling pathway and activation by glucocorticoid receptors can restore downstream signaling in prostate cancer by alternative proteins. Multiple clinical trials are underway exploring therapeutic strategies to overcome these resistance mechanisms.

Robust Glycogene-Based Prognostic Signature for Proficient Mismatch Repair Colorectal Adenocarcinoma

Background

Proficient mismatch repair (pMMR) colorectal adenocarcinoma (CRAC) metastasizes to a greater extent than MMR-deficient CRAC. Prognostic biomarkers are preferred in clinical practice. However, traditional biomarkers screened directly from sequencing are often not robust and thus cannot be confidently utilized.

Methods

To circumvent the drawbacks of blind screening, we established a new strategy to identify prognostic biomarkers in the conserved and specific oncogenic pathway and its regulatory RNA network. We performed RNA sequencing (RNA-seq) for messenger RNA (mRNA) and noncoding RNA in six pMMR CRAC patients and constructed a glycosylation-related RNA regulatory network. Biomarkers were selected based on the network and their correlation with the clinicopathologic information and were validated in multiple centers (n = 775).

Results

We constructed a competing endogenous RNA (ceRNA) regulatory network using RNA-seq. Genes associated with glycosylation pathways were embedded within this scale-free network. Moreover, we further developed and validated a seven-glycogene prognosis signature, GlycoSig (B3GNT6, GALNT3, GALNT8, ALG8, STT3B, SRD5A3, and ALG6) that prognosticate poor-prognostic subtype for pMMR CRAC patients. This biomarker set was validated in multicenter datasets, demonstrating its robustness and wide applicability. We constructed a simple-to-use nomogram that integrated the risk score of GlycoSig and clinicopathological features of pMMR CRAC patients.

Conclusions

The seven-glycogene signature served as a novel and robust prognostic biomarker set for pMMR CRAC, highlighting the role of a dysregulated glycosylation network in poor prognosis.

Characterization of Proteins Regulated by Androgen and Protein Kinase a Signaling in VCaP Prostate Cancer Cells

Androgen signaling via the androgen receptor (AR) is involved in normal prostate development and prostate cancer progression. In addition to androgen binding, a variety of protein kinases, including cyclic AMP-dependent protein kinase A (PKA), can activate the AR. Although hormone deprivation, especially that of androgen, continues to be an important strategy for treating prostate cancer patients, the disease ultimately progresses to castration-resistant prostate cancer (CRPC), despite a continuous hormone-deprived environment. To date, it remains unclear which pathways in this progression are active and targetable. Here, we performed a proteomic analysis of VCaP cells stimulated with androgen or forskolin to identify proteins specific for androgen-induced and androgen-bypassing signaling, respectively. Patterns of differentially expressed proteins were quantified, and eight proteins showing significant changes in expression were identified. Functional information, including a Gene Ontology analysis, revealed that most of these proteins are involved in metabolic processes and are associated with cancer. The mRNA and protein expression of selected proteins was validated, and functional correlations of identified proteins with signaling in VCaP cells were assessed by measuring metabolites related to each enzyme. These analyses offered new clues regarding effector molecules involved in prostate cancer development, insights that are supported by the demonstration of increased expression levels of the eight identified proteins in prostate cancer patients and assessments of the progression-free interval. Taken together, our findings show that aberrant levels of eight proteins reflect molecular changes that are significantly regulated by androgen and/or PKA signaling pathways, suggesting possible molecular mechanisms of CRPC.

Somatic Alterations Impact AR Transcriptional Activity and Efficacy of AR-Targeting Therapies in Prostate Cancer

Simple Summary

For patients whose prostate cancer spreads beyond the confines of the prostate, treatment options continue to increase. However, we are missing the information that is needed to choose for each patient the best treatment at each step of his cancer progression so we can ensure that maximal remissions and prolonged survival are achieved. In this review, we examine whether a better understanding of how the activity of the target for the default first treatment, the androgen receptor, is regulated in prostate cancer tissues can improve prostate cancer treatment plans. We consider the evidence for variability of androgen receptor activity among patients and examine the molecular basis for this variable action. We summarize clinical evidence supporting that information on a prostate cancer’s genomic composition may inform on its level of androgen receptor action, which may facilitate choice for the most effective first-line therapy and ultimately improve prostate cancer treatment plans overall.

Abstract

Inhibiting the activity of the ligand-activated transcription factor androgen receptor (AR) is the default first-line treatment for metastatic prostate cancer (CaP). Androgen deprivation therapy (ADT) induces remissions, however, their duration varies widely among patients. The reason for this heterogeneity is not known. A better understanding of its molecular basis may improve treatment plans and patient survival. AR’s transcriptional activity is regulated in a context-dependent manner and relies on an interplay between its associated transcriptional regulators, DNA recognition motifs, and ligands. Alterations in one or more of these factors induce shifts in the AR cistrome and transcriptional output. Significant variability in AR activity is seen in both castration-sensitive (CS) and castration-resistant CaP (CRPC). Several AR transcriptional regulators undergo somatic alterations that impact their function in clinical CaPs. Some alterations occur in a significant fraction of cases, resulting in CaP subtypes, while others affect only a few percent of CaPs. Evidence is emerging that these alterations may impact the response to CaP treatments such as ADT, radiation therapy, and chemotherapy. Here, we review the contribution of recurring somatic alterations on AR cistrome and transcriptional output and the efficacy of CaP treatments and explore strategies to use these insights to improve treatment plans and outcomes for CaP patients.

Aldo-Keto Reductases and Cancer Drug Resistance

Human aldo-keto reductases (AKRs) catalyze the NADPH-dependent reduction of carbonyl groups to alcohols for conjugation reactions to proceed. They are implicated in resistance to cancer chemotherapeutic agents either because they are directly involved in their metabolism or help eradicate the cellular stress created by these agents (e.g., reactive oxygen species and lipid peroxides). Furthermore, this cellular stress activates the Nuclear factor-erythroid 2 p45-related factor 2 (NRF2)-Kelch-like ECH-associated protein 1 pathway. As many human AKR genes are upregulated by the NRF2 transcription factor, this leads to a feed-forward mechanism to enhance drug resistance. Resistance to major classes of chemotherapeutic agents (anthracyclines, mitomycin, cis-platin, antitubulin agents, vinca alkaloids, and cyclophosphamide) occurs by this mechanism. Human AKRs also catalyze the synthesis of androgens and estrogens and the elimination of progestogens and are involved in hormonal-dependent malignancies. They are upregulated by antihormonal therapy providing a second mechanism for cancer drug resistance. Inhibitors of the NRF2 system or pan-AKR1C inhibitors offer promise to surmount cancer drug resistance and/or synergize the effects of existing drugs. SIGNIFICANCE STATEMENT: Aldo-keto  reductases (AKRs) are overexpressed in a large number of human tumors and mediate resistance to cancer chemotherapeutics and antihormonal therapies. Existing drugs and new agents in development may surmount this resistance by acting as specific AKR isoforms or AKR pan-inhibitors to improve clinical outcome.

Developmental exposure to chlordecone induces transgenerational effects in somatic prostate tissue which are associated with epigenetic histone trimethylation changes

BACKGROUND

Chlordecone (CD), also known as Kepone, is an organochlorine insecticide that has been used in banana crops in the French West Indies. Due to long-term contamination of soils and water, the population is still exposed to CD. Exposure to CD in adulthood is associated with an increased risk of prostate cancer (PCa).

OBJECTIVES

We examined the transgenerational effects of CD on murine prostate tissue.

METHODS

We exposed pregnant Swiss mice to CD. The prostates from directly exposed (F1) and non-exposed (F3) male progeny were analyzed. We used immunofluorescence, RNA-seq and ChIP-seq techniques for the comprehensive analyses of chromatin states in prostate.

RESULTS

We observed an increased prostatic intraepithelial neoplasia phenotype (PIN) in both F1 and F3 generations. Transcriptomic analysis in CD-derived F1 and F3 prostate using RNA-seq revealed that 970 genes in F1 and 218 in F3 genes were differentially expressed. The differentially expressed genes in both datasets could be clustered accordingly to common biological processes, "cell differentiation", "developmental process", "regulating of signaling", suggesting that in both generations similar processes were perturbed. We detected that in both datasets several Hox genes were upregulated; in F1, the expression was detected mainly in Hoxb and Hoxd, and in F3, in Hoxa family genes. Using a larger number of biological replicates and RT-qPCR we showed that genes implicated in testosterone synthesis (Akr1b3, Cyp11a1, Cyp17a1, Srd5a1) were dramatically upregulated in PIN samples; Cyp19a1, converting testosterone to estradiol was elevated as well. We found a dramatic increase in Esr2 expression both in F1 and F3 prostates containing PIN. The PIN-containing samples have a strong increase in expression of self-renewal-related genes (Nanog, Tbx3, Sox2, Sox3, Rb1). We observed changes in liver, F1 CD-exposed males have an increased expression of genes related to DNA repair, matrix collagen and inflammation related pathways in F1 but not in F3 adult CD-derived liver. The changes in RNA transcription were associated with epigenetic changes. Specifically, we found a global increase in H3K4 trimethylation (H3K4me3) and a decrease in H3K27 trimethylation (H3K27me3) in prostate of F1 mice. ChIP-seq analysis showed that 129 regions in F1 and 240 in F3 acquired altered H3K4me3 occupancy in CD-derived prostate, including highest increase at several promoters of Hoxa family genes in both datasets. The alteration in H3K4me3 in both generations overlap 73 genes including genes involved in proliferation regulation, Tbx2, Stat3, Stat5a, Pou2f3 and homeobox genes Hoxa13, Hoxa9.

CONCLUSIONS

Our data suggest that developmental exposure to CD leads to epigenetic changes in prostate tissue. The PIN containing samples showed evidence of implication in hormonal pathway and self-renewal gene expression that have the capacity to promote neoplasia in CD-exposed mice.

Gene polymorphism-related differences in the outcomes of abiraterone for prostate cancer: a systematic overview

Numerous prostate cancer (PC) associated genes have been reported in previous genome-wide association studies. Elucidation of prostate cancer pharmacogenomics have enhanced studies into the impact of germline genetic changes on treatment, in addition to evaluating related genomic alterations and biomarkers in prostate tumor tissues. Currently, Abiraterone (Abi) is used as one of the therapeutic options for PC. In this article, germline variants that have been associated with responses to Abi in patients with advanced PC are summarized. These include biomarker genes such as CYP17A1, AR-V7, HSD3B1, SLCO2B1, SULT1E1, and SRD5A2 that are involved in homologous recombination, as well as in gene expression mutations in important signaling pathways, such as WNT and Abi metabolic pathways.

Back where it belongs: 11β-hydroxyandrostenedione compels the re-assessment of C11-oxy androgens in steroidogenesis

Adrenal steroidogenesis has, for decades, been depicted as three biosynthesis pathways -the mineralocorticoid, glucocorticoid and androgen pathways with aldosterone, cortisol and androstenedione as the respective end products. 11β-hydroxyandrostenedione was not included as an adrenal steroid despite the adrenal output of this steroid being twice that of androstenedione. While it is the end of the line for aldosterone and cortisol, as it is in these forms that they exhibit their most potent receptor activities prior to inactivation and conjugation, 11β-hydroxyandrostenedione is another matter entirely. The steroid, which is weakly androgenic, has its own designated pathway yielding 11-ketoandrostenedione, 11β-hydroxytestosterone and the potent androgens, 11-ketotestosterone and 11-ketodihydrotestosterone, primarily in the periphery. Over the last decade, these C11-oxy C₁₉ steroids have once again come to the fore with the rising number of studies contradicting the generally accepted notion that testosterone and it's 5α-reduced product, dihydrotestosterone, are the principal potent androgens in humans. These C11-oxy androgens have been shown to contribute to the androgen milieu in adrenal disorders associated with androgen excess and in androgen dependant disease progression. In this review, we will highlight these overlooked C11-oxy C₁₉ steroids as well as the C11-oxy C₂₁ steroids and their contribution to congenital adrenal hyperplasia, polycystic ovarian syndrome and prostate cancer. The focus is on new findings over the past decade which are slowly but surely reshaping our current outlook on human sex steroid biology.

Differential Expression of a Panel of Ten CNTN1-Associated Genes during Prostate Cancer Progression and the Predictive Properties of the Panel Towards Prostate Cancer Relapse

Contactin 1 (CNTN1) is a new oncogenic protein of prostate cancer (PC); its impact on PC remains incompletely understood. We observed CNTN1 upregulation in LNCaP cell-derived castration-resistant PCs (CRPC) and CNTN1-mediated enhancement of LNCaP cell proliferation. CNTN1 overexpression in LNCaP cells resulted in enrichment of the CREIGHTON_ENDOCRINE_THERAPY_RESISTANCE_3 gene set that facilitates endocrine resistance in breast cancer. The leading-edge (LE) genes (n = 10) of this enrichment consist of four genes with limited knowledge on PC and six genes novel to PC. These LE genes display differential expression during PC initiation, metastatic progression, and CRPC development, and they predict PC relapse following curative therapies at hazard ratio (HR) 2.72, 95% confidence interval (CI) 1.96–3.77, and p = 1.77 × 10⁻⁹ in The Cancer Genome Atlas (TCGA) PanCancer cohort (n = 492) and HR 2.72, 95% CI 1.84–4.01, and p = 4.99 × 10⁻⁷ in Memorial Sloan Kettering Cancer Center (MSKCC) cohort (n = 140). The LE gene panel classifies high-, moderate-, and low-risk of PC relapse in both cohorts. Additionally, the gene panel robustly predicts poor overall survival in clear cell renal cell carcinoma (ccRCC, p = 1.13 × 10⁻¹¹), consistent with ccRCC and PC both being urogenital cancers. Collectively, we report multiple CNTN1-related genes relevant to PC and their biomarker values in predicting PC relapse.

Steroidogenesis in Peripheral and Transition Zones of Human Prostate Cancer Tissue

The peripheral zone (PZ) and transition zone (TZ) represent about 70% of the human prostate gland with each zone having differential ability to develop prostate cancer. Androgens and their receptor are the primary driving cause of prostate cancer growth and eventually castration-resistant prostate cancer (CRPC). De novo steroidogenesis has been identified as a key mechanism that develops during CRPC. Currently, there is very limited information available on human prostate tissue steroidogenesis. The purpose of the present study was to investigate steroid metabolism in human prostate cancer tissues with comparison between PZ and TZ. Human prostate cancer tumors were procured from the patients who underwent radical prostatectomy without any neoadjuvant therapy. Human prostate homogenates were used to quantify steroid levels intrinsically present in the tissues as well as formed after incubation with 2 µg/mL of 17-hydroxypregnenolone (17-OH-pregnenolone) or progesterone. A Waters Acquity ultraperformance liquid chromatography coupled to a Quattro Premier XE tandem quadrupole mass spectrometer using a C₁₈ column was used to measure thirteen steroids from the classical and backdoor steroidogenesis pathways. The intrinsic prostate tissue steroid levels were similar between PZ and TZ with dehydroepiandrosterone (DHEA), dihydrotestosterone (DHT), pregnenolone and 17-OH-pregnenolone levels higher than the other steroids measured. Interestingly, 5-pregnan-3,20-dione, 5-pregnan-3-ol-20-one, and 5-pregnan-17-ol-3,20-dione formation was significantly higher in both the zones of prostate tissues, whereas, androstenedione, testosterone, DHT, and progesterone levels were significantly lower after 60 min incubation compared to the 0 min control incubations. The incubations with progesterone had a similar outcome with 5-pregnan-3,20-dione and 5-pregnan-3-ol-20-one levels were elevated and the levels of DHT were lower in both PZ and TZ tissues. The net changes in steroid formation after the incubation were more observable with 17-OH-pregnenolone than with progesterone. In our knowledge, this is the first report of comprehensive analyses of intrinsic prostate tissue steroids and precursor-driven steroid metabolism using a sensitive liquid chromatography-mass spectrometry assay. In summary, the PZ and TZ of human prostate exhibited similar steroidogenic ability with distinction in the manner each zone utilizes the steroid precursors to divert the activity towards backdoor pathway through a complex matrix of steroidogenic mechanisms.

Using biochemistry and biophysics to extinguish androgen receptor signaling in prostate cancer

Castration resistant prostate cancer (CRPC) continues to be androgen receptor (AR) driven. Inhibition of AR signaling in CRPC could be advanced using state-of-the-art biophysical and biochemical techniques. Structural characterization of AR and its complexes by cryo-electron microscopy would advance the development of N-terminal domain (NTD) and ligand-binding domain (LBD) antagonists. The structural basis of AR function is unlikely to be determined by any single structure due to the intrinsic disorder of its NTD, which not only interacts with coregulators but likely accounts for the constitutive activity of AR-splice variants (SV), which lack the LBD and emerge in CRPC. Using different AR constructs lacking the LBD, their effects on protein folding, DNA binding, and transcriptional activity could reveal how interdomain coupling explains the activity of AR-SVs. The AR also interacts with coregulators that promote chromatin looping. Elucidating the mechanisms involved can identify vulnerabilities to treat CRPC, which do not involve targeting the AR. Phosphorylation of the AR coactivator MED-1 by CDK7 is one mechanism that can be blocked by the use of CDK7 inhibitors. CRPC gains resistance to AR signaling inhibitors (ARSI). Drug resistance may involve AR-SVs, but their role requires their reliable quantification by SILAC-mass spectrometry during disease progression. ARSI drug resistance also occurs by intratumoral androgen biosynthesis catalyzed by AKR1C3 (type 5 17β-hydroxysteroid dehydrogenase), which is unique in that its acts as a coactivator of AR. Novel bifunctional inhibitors that competitively inhibit AKR1C3 and block its coactivator function could be developed using reverse-micelle NMR and fragment-based drug discovery.

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.

Cellular growth factors as prospective therapeutic targets for combination therapy in androgen independent prostate cancer (AIPC)

Cancer is the second leading cause of death worldwide, with prostate cancer, the second most commonly diagnosed cancer among men. Prostate cancer develops in the peripheral zone of the prostate gland, and the initial progression largely depends on androgens, the male reproductive hormone that regulates the growth and development of the prostate gland and testis. The currently available treatments for androgen dependent prostate cancer are, however, effective for a limited period, where the patients show disease relapse, and develop androgen-independent prostate cancer (AIPC). Studies have shown various intricate cellular processes such as, deregulation in multiple biochemical and signaling pathways, intra-tumoral androgen synthesis; AR over-expression and mutations and AR activation via alternative growth pathways are involved in progression of AIPC. The currently approved treatment strategies target a single cellular protein or pathway, where the cells slowly develop resistance and adapt to proliferate via other cellular pathways over a period of time. Therefore, an increased research aims to understand the efficacy of combination therapy, which targets multiple interlinked pathways responsible for acquisition of resistance and survival. The combination therapy is also shown to enhance efficacy as well as reduce toxicity of the drugs. Thus, the present review focuses on the signaling pathways involved in the progression of AIPC, comprising a heterogeneous population of cells and the advantages of combination therapy. Several clinical and pre-clinical studies on a variety of combination treatments have shown beneficial outcomes, yet further research is needed to understand the potential of combination therapy and its diverse strategies.

Rapamycin inhibits AR signaling pathway in prostate cancer by interacting with the FK1 domain of FKBP51

Reactivation of the androgen receptor signaling pathway in the emasculated environment is the main reason for the occurrence of castration-resistant prostate cancer (CRPC). The immunophilin FKBP51, as a co-chaperone protein, together with Hsp90 help the correct folding of AR. Rapamycin is a known small-molecule inhibitor of FKBP51, but its effect on the FKBP51/AR signaling pathway is not clear. In this study, the interaction mechanism between FKBP51 and rapamycin was investigated using steady-state fluorescence quenching, X-ray crystallization, MTT assay, and qRT-PCR. Steady-state fluorescence quenching assay showed that rapamycin could interact with FKBP51. The crystal of the rapamycin-FKBP51 complex indicated that rapamycin occupies the hydrophobic binding pocket of FK1 domain which is vital for AR activity. The residues involving rapamycin binding are mainly hydrophobic and may overlap with the AR interaction site. Further assays showed that rapamycin could inhibit the androgen-dependent growth of human prostate cancer cells by down-regulating the expression levels of AR activated downstream genes. Taken together, our study demonstrates that rapamycin suppresses AR signaling pathway by interfering with the interaction between AR and FKBP51. The results of this study not only can provide useful information about the interaction mechanism between rapamycin and FKBP51, but also can provide new clues for the treatment of prostate cancer and castration-resistant prostate cancer.

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Rapamycin occupies the hydrophobic binding pocket of FK1 domain of FKBP51.

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Rapamycin suppresses the AR signaling pathway by interacting with FKBP51.

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Rapamycin inhibits the growth of prostate cancer cells via the AR signaling pathway.

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.

11-Oxygenated androgens in health and disease

The adrenal gland is a source of sex steroid precursors, and its activity is particularly relevant during fetal development and adrenarche. Following puberty, the synthesis of androgens by the adrenal gland has been considered of little physiologic importance. Dehydroepiandrosterone (DHEA) and its sulfate, DHEAS, are the major adrenal androgen precursors, but they are biologically inactive. The second most abundant unconjugated androgen produced by the human adrenals is 11β-hydroxyandrostenedione (11OHA4). 11-Ketotestosterone, a downstream metabolite of 11OHA4 (which is mostly produced in peripheral tissues), and its 5α-reduced product, 11-ketodihydrotestosterone, are bioactive androgens, with potencies equivalent to those of testosterone and dihydrotestosterone. These adrenal-derived androgens all share an oxygen atom on carbon 11, so we have collectively termed them 11-oxyandrogens. Over the past decade, these androgens have emerged as major components of several disorders of androgen excess, such as congenital adrenal hyperplasia, premature adrenarche and polycystic ovary syndrome, as well as in androgen-dependent tumours, such as castration-resistant prostate cancer. Moreover, in contrast to the more extensively studied, traditional androgens, circulating concentrations of 11-oxyandrogens do not demonstrate an age-dependent decline. This Review focuses on the rapidly expanding knowledge regarding the implications of 11-oxyandrogens in human physiology and disease.

CYP17A1 exhibits 17αhydroxylase/17,20-lyase activity towards 11β-hydroxyprogesterone and 11-ketoprogesterone metabolites in the C11-oxy backdoor pathway

Cytochrome P450 17α-hydroxylase/17,20-lyase (CYP17A1) plays a pivotal role in the regulation of adrenal and gonadal steroid hormone biosynthesis. More recent studies highlighted the enzyme's role in the backdoor pathway leading to androgen production. Increased CYP17A1 activity in endocrine disorders and diseases are associated with elevated C₂₁ and C₁₉ steroids which include 17α-hydroxyprogesterone and androgens, as well as C11-oxy C₂₁ and C11-oxy C₁₉ steroids. We previously reported that 11β-hydroxyprogesterone (11OHP4), 21-deoxycortisol (21dF) and their keto derivatives are converted by 5α-reductases and hydroxysteroid dehydrogenases yielding C₁₉ steroids in the backdoor pathway. In this study the 17α-hydroxylase and 17,20-lyase activity of CYP17A1 towards the unconventional C11-oxy C₂₁ steroid substrates and their 5α- and 3α,5α-reduced metabolites was investigated in transfected HEK-293 cells. CYP17A1 catalysed the 17α-hydroxylation of 11OHP4 to 21dF and 11-ketoprogesterone (11KP4) to 21-deoxycortisone (21dE) with negligible hydroxylation of their 5α-reduced metabolites while no lyase activity was detected. The 3α,5α-reduced C11-oxy C₂₁ steroids-5α-pregnan-3α,11β-diol-20-one (3,11diOH-DHP4) and 5α-pregnan-3α-ol-11,20-dione (alfaxalone) were rapidly hydroxylated to 5α-pregnan-3α,11β,17α-triol-20-one (11OH-Pdiol) and 5α-pregnan-3α,17α-diol-11,20-dione (11K-Pdiol), with the lyase activity subsequently catalysing to conversion to the C11-oxy C₁₉ steroids, 11β-hydroxyandrosterone and 11-ketoandrosterone, respectively. Docking of 11OHP4, 11KP4 and the 5α-reduced metabolites, 5α-pregnan-11β-ol-3,20-dione (11OH-DHP4) and 5α-pregnan-3,11,20-trione (11K-DHP4) with human CYP17A1 showed minimal changes in the orientation of these C11-oxy C₂₁ steroids in the active pocket when compared with the binding of progesterone suggesting the 17,20-lyase is impaired by the C11-hydroxyl and keto moieties. The structurally similar 3,11diOH-DHP4 and alfaxalone showed a greater distance between C17 and the heme group compared to the natural substrate, 17α-hydroxypregnenolone potentially allowing more orientational freedom and facilitating the conversion of the C11-oxy C₂₁ to C11-oxy C₁₉ steroids. In summary, our in vitro assays showed that while CYP17A1 readily hydroxylated 11OHP4 and 11KP4, the enzyme was unable to catalyse the 17,20-lyase reaction of these C11-oxy C₂₁ steroid products. Although CYP17A1 exhibited no catalytic activity towards the 5α-reduced intermediates, once the C4-C5 double bond and the keto group at C3 were reduced, both the hydroxylation and lyase reactions proceeded efficiently. These findings show that the C11-oxy C₂₁ steroids could potentially contribute to the androgen pool in tissue expressing steroidogenic enzymes in the backdoor pathway.

A Mansonone Derivative Coupled with Monoclonal Antibody 4D5-Modified Chitosan Inhibit AKR1C3 to Treat Castration-Resistant Prostate Cancer

Purpose

Aldo-ketoreductase (AKR) 1C3 is crucial for testosterone synthesis. Abnormally high expression/activity of AKR1C3 can promote castration-resistant prostate cancer (CRPC). A mansonone derivative and AKR1C3 inhibitor, 6e, was combined with 4D5 (extracellular fragment of the monoclonal antibody of human epidermal growth factor receptor-2)-modified chitosan to achieve a nanodrug-delivery system (CS-4D5/6e) to treat CRPC.

Materials and Methods

Morphologies/properties of CS-4D5/6e were characterized by atomic force microscopy, zeta-potential analysis, and Fourier transform-infrared spectroscopy. CS-4D5/6e uptake was measured by immunofluorescence under confocal laser scanning microscopy. Testosterone in LNCaP cells overexpressing human AKR1C3 (LNCaP-AKR1C3) and cell lysates was measured to reflect AKR1C3 activity. Androgen receptor (AR) and prostate-specific antigen (PSA) expression was measured by Western blotting. CS-4D5/6e-based inhibition of AKR1C3 was evaluated in tumor-xenografted mice.

Results

CS-4D5/6e was oblate, with a particle size of 200-300 nm and thickness of 1-5 nm. Zeta potential was 1.39±0.248 mV. 6e content in CS-4D5/6e was 7.3±1.4% and was 18±3.6% for 4D5. 6e and CS-4D5/6e inhibited testosterone production significantly in a concentration-dependent manner in LNCaP-AKR1C3 cells, and a decrease in expression of AKR1C3, PSA, and AR was noted. Half-maximal inhibitory concentration of CS-4D5/6e on LNCaP-AKR1C3 cells was significantly lower than that in LNCaP cells (P<0.05). CS-4D5/6e significantly reduced growth of 22Rv1 tumor xenografts by 57.00% compared with that in the vehicle group (P<0.01).

Conclusion

We demonstrated the antineoplastic activity of a potent AKR1C3 inhibitor (6e) and its nanodrug-delivery system (CS-4D5/6e). First, CS-4D5/6e targeted HER2-positive CRPC cells. Second, it transferred 6e (an AKR1C3 inhibitor) to achieve a reduction in intratumoral testosterone production. Compared with 6e, CS-4D5/6e showed lower systemic toxicity. CS-4D5/6e inhibited tumor growth effectively in mice implanted with tumor xenografts by downregulating testosterone production mediated by intratumoral AKR1C3. These results showed a promising strategy for treatment of the CRPC that develops invariably in prostate-cancer patients.

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.

Nuclear receptor ERRα contributes to castration-resistant growth of prostate cancer via its regulation of intratumoral androgen biosynthesis

Enhanced intratumoral androgen biosynthesis and persistent androgen receptor (AR) signaling are key factors responsible for the relapse growth of castration-resistant prostate cancer (CRPC). Residual intraprostatic androgens can be produced by de novo synthesis of androgens from cholesterol or conversion from adrenal androgens by steroidogenic enzymes expressed in prostate cancer cells via different steroidogenic pathways. However, the dysregulation of androgen biosynthetic enzymes in CRPC still remains poorly understood. This study aims to elucidate the role of the nuclear receptor, estrogen-related receptor alpha (ERRα, ESRRA), in the promotion of androgen biosynthesis in CRPC growth. Methods: ERRα expression in CRPC patients was analyzed using Gene Expression Omnibus (GEO) datasets and validated in established CRPC xenograft model. The roles of ERRα in the promotion of castration-resistant growth were elucidated by overexpression and knockdown studies and the intratumoral androgen levels were measured by UPLC-MS/MS. The effect of suppression of ERRα activity in the potentiation of sensitivity to androgen-deprivation was determined using an ERRα inverse agonist. Results: ERRα exhibited an increased expression in metastatic CRPC and CRPC xenograft model, could act to promote castration-resistant growth via direct transactivation of two key androgen synthesis enzymes CYP11A1 and AKR1C3, and hence enhance intraprostatic production of dihydrotestosterone (DHT) and activation of AR signaling in prostate cancer cells. Notably, inhibition of ERRα activity by an inverse agonist XCT790 could reduce the DHT production and suppress AR signaling in prostate cancer cells. Conclusion: Our study reveals a new role of ERRα in the intratumoral androgen biosynthesis in CRPC via its transcriptional control of steroidogenic enzymes, and also provides a novel insight that targeting ERRα could be a potential androgen-deprivation strategy for the management of CRPC.

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.

Role of Lipoproteins in the Microenvironment of Hormone-Dependent Cancers

The tumor microenvironment (TME) is an attractive target to develop novel strategies for hormone-dependent cancers. Several molecules in the TME can favor tumor development and progression, including lipoproteins. Lipoproteins are taken up by cancer cells, providing them with cholesterol and fatty acids. Cholesterol regulates cell signaling and it is converted into a series of bioactive metabolites, including hormones. The conflicting results of epidemiological and interventional studies suggest that the local availability of lipoproteins in the TME is more relevant for cancer biology than their circulating levels. Thus, reducing lipoprotein uptake and stimulating cell cholesterol efflux to high-density lipoproteins (HDLs) can represent a novel adjuvant strategy for cancer management. HDL-like particles can also act as drug delivery systems for tumor targeting.

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

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

Intracrinology-revisited and prostate cancer

The formation of steroid hormones in peripheral target tissues is referred to as their intracrine formation. This process occurs in hormone dependent malignancies such as prostate and breast cancer in which the disease can be either castrate resistant or occur post-menopausally, respectively. In these instances, the major precursor steroid of androgens and estrogens is dehydroepiandrosterone (DHEA) and DHEA-SO4. This article reviews the major pathways by which adrenal steroids are converted to the potent male sex hormones, testosterone (T) and 5α-dihydrotestosterone (5α-DHT) and the discrete enzyme isoforms involved in castration resistant prostate cancer. Previous studies have mainly utilized radiotracers to investigate these pathways but have not used prevailing concentrations of precursors found in castrate male human serum. In addition, the full power of stable-isotope dilution liquid chromatography tandem mass spectrometry has not been applied routinely. Furthermore, it is clear that adaptive responses occur in the transporters and enzyme isoforms involved in response to androgen deprivation therapy that need to be considered.

Inhibitory Interplay of SULT2B1b Sulfotransferase with AKR1C3 Aldo-keto Reductase in Prostate Cancer

SULT2B1b (SULT2B) is a prostate-expressed hydroxysteroid sulfotransferase, which may regulate intracrine androgen homeostasis by mediating 3β-sulfation of dehydroepiandrosterone (DHEA), the precursor for 5α-dihydrotestosterone (DHT) biosynthesis. The aldo-keto reductase (AKR)1C3 regulates androgen receptor (AR) activity in castration-resistant prostate cancer (CRPC) by promoting tumor tissue androgen biosynthesis from adrenal DHEA and also by functioning as an AR-selective coactivator. Herein we report that SULT2B-depleted CRPC cells, arising from stable RNA interference or gene knockout (KO), are markedly upregulated for AKR1C3, activated for ERK1/2 survival signal, and induced for epithelial-to-mesenchymal (EMT)-like changes. EMT was evident from increased mesenchymal proteins and elevated EMT-inducing transcription factors SNAI1 and TWIST1 in immunoblot and single-cell mass cytometry analyses. SULT2B KO cells showed greater motility and invasion in vitro; growth escalation in xenograft study; and enhanced metastatic potential predicted on the basis of decreased cell stiffness and adhesion revealed from atomic force microscopy analysis. While AR and androgen levels were unchanged, AR activity was elevated, since PSA and FKBP5 mRNA induction by DHT-activated AR was several-fold higher in SULT2B-silenced cells. AKR1C3 silencing prevented ERK1/2 activation and SNAI1 induction in SULT2B-depleted cells. SULT2B was undetectable in nearly all CRPC metastases from 50 autopsy cases. Primary tumors showed variable and Gleason score (GS)-independent SULT2B levels. CRPC metastases lacking SULT2B expressed AKR1C3. Since AKR1C3 is frequently elevated in advanced prostate cancer, the inhibitory influence of SULT2B on AKR1C3 upregulation, ERK1/2 activation, EMT-like induction, and on cell motility and invasiveness may be clinically significant. Pathways regulating the inhibitory SULT2B-AKR1C3 axis may inform new avenue(s) for targeting SULT2B-deficient prostate cancer.

Cancer-associated fibroblasts promote prostate tumor growth and progression through upregulation of cholesterol and steroid biosynthesis

Background

Androgen receptor targeted therapies have emerged as an effective tool to manage advanced prostate cancer (PCa). Nevertheless, frequent occurrence of therapy resistance represents a major challenge in the clinical management of patients, also because the molecular mechanisms behind therapy resistance are not yet fully understood. In the present study, we therefore aimed to identify novel targets to intervene with therapy resistance using gene expression analysis of PCa co-culture spheroids where PCa cells are grown in the presence of cancer-associated fibroblasts (CAFs) and which have been previously shown to be a reliable model for antiandrogen resistance.

Methods

Gene expression changes of co-culture spheroids (LNCaP and DuCaP seeded together with CAFs) were identified by Illumina microarray profiling. Real-time PCR, Western blotting, immunohistochemistry and cell viability assays in 2D and 3D culture were performed to validate the expression of selected targets in vitro and in vivo. Cytokine profiling was conducted to analyze CAF-conditioned medium.

Results

Gene expression analysis of co-culture spheroids revealed that CAFs induced a significant upregulation of cholesterol and steroid biosynthesis pathways in PCa cells. Cytokine profiling revealed high amounts of pro-inflammatory, pro-migratory and pro-angiogenic factors in the CAF supernatant. In particular, two genes, 3-hydroxy-3-methylglutaryl-Coenzyme A synthase 2 (HMGCS2) and aldo-keto reductase family 1 member C3 (AKR1C3), were significantly upregulated in PCa cells upon co-culture with CAFs. Both enzymes were also significantly increased in human PCa compared to benign tissue with AKR1C3 expression even being associated with Gleason score and metastatic status. Inhibiting HMGCS2 and AKR1C3 resulted in significant growth retardation of co-culture spheroids as well as of various castration and enzalutamide resistant cell lines in 2D and 3D culture, underscoring their putative role in PCa. Importantly, dual targeting of cholesterol and steroid biosynthesis with simvastatin, a commonly prescribed cholesterol synthesis inhibitor, and an inhibitor against AKR1C3 had the strongest growth inhibitory effect.

Conclusions

From our results we conclude that CAFs induce an upregulation of cholesterol and steroid biosynthesis in PCa cells, driving them into AR targeted therapy resistance. Blocking both pathways with simvastatin and an AKR1C3 inhibitor may therefore be a promising approach to overcome resistances to AR targeted therapies in PCa.

Gene Expression Alterations during Development of Castration-Resistant Prostate Cancer Are Detected in Circulating Tumor Cells

Development of castration-resistant prostate cancer (CRPC) is associated with alterations in gene expression involved in steroidogenesis and androgen signaling. This study investigates whether gene expression changes related to CRPC development can be identified in circulating tumor cells (CTCs). Gene expression in paired CTC samples from 29 patients, before androgen deprivation therapy (ADT) and at CRPC relapse, was compared using a panel including 47 genes related to prostate cancer progression on a qPCR platform. Fourteen genes displayed significantly changed gene expression in CTCs at CRPC relapse compared to before start of ADT. The genes with increased expression at CRPC relapse were related to steroidogenesis, AR-signaling, and anti-apoptosis. In contrast, expression of prostate markers was downregulated at CRPC. We also show that midkine (MDK) expression in CTCs from metastatic hormone-sensitive prostate cancer (mHSPC) was associated to short cancer-specific survival (CSS). In conclusion, this study shows that gene expression patterns in CTCs reflect the development of CRPC, and that MDK expression levels in CTCs are prognostic for cancer-specific survival in mHSPC. This study emphasizes the role of CTCs in exploring mechanisms of therapy resistance, as well as a promising biomarker for prognostic and treatment-predictive purposes in advanced mHSPC.

Prospective evaluation of urinary steroids and prostate carcinoma-induced deviation: preliminary results

BACKGROUND

The serum prostate-specific antigen is the most widespread biomarker for prostate disease. Its low specificity for prostatic malignancies is a matter of concern and the reason why new biomarkers for screening purposes are needed. The correlation between altered production of the main steroids and prostate carcinoma (PCa) occurrence is historically known. The purpose of this study is to evaluate the modifications of a comprehensive urinary endogenous steroidal profile (USP) induced by PCa, by multivariate statistical methods.

METHODS

A total of 283 Italian subjects were included in the study, 139 controls and 144 PCa-affected patients. The USP, including 17 steroids and five urinary steroidal ratios, was quantitatively evaluated using gas chromatography coupled with single quadrupole mass spectrometry (GC-MS). The data were interpreted using a chemometric, multivariate approach (intrinsically more sensible to alterations with respect to traditional statistics) and a model for the discrimination of cancer-affected profiles was built.

RESULTS

Two multivariate classification models were calculated, the former including three steroids with the highest statistical significance (e.g. testosterone, etiocholanolone and 7β-OH-DHEA) and PSA values, the latter considering the three steroids' levels only. Both models yielded high sensitivity and specificity scores near to 70%, resulting significantly higher than PSA alone.

CONCLUSIONS

Three USP steroids resulted significantly altered in our PCa population. These preliminary results, combined with the simplicity and low-cost of the analysis, open to further investigation of the potential role of this restricted USP in PCa diagnosis.

CDK7 Inhibition Suppresses Castration-Resistant Prostate Cancer through MED1 Inactivation

Metastatic castration-resistant prostate cancer (CRPC) is a fatal disease, primarily resulting from the transcriptional addiction driven by androgen receptor (AR). First-line CRPC treatments typically target AR signaling, but are rapidly bypassed, resulting in only a modest survival benefit with antiandrogens. Therapeutic approaches that more effectively block the AR-transcriptional axis are urgently needed. Here, we investigated the molecular mechanism underlying the association between the transcriptional coactivator MED1 and AR as a vulnerability in AR-driven CRPC. MED1 undergoes CDK7-dependent phosphorylation at T1457 and physically engages AR at superenhancer sites, and is essential for AR-mediated transcription. In addition, a CDK7-specific inhibitor, THZ1, blunts AR-dependent neoplastic growth by blocking AR/MED1 corecruitment genome-wide, as well as reverses the hyperphosphorylated MED1-associated enzalutamide-resistant phenotype. In vivo, THZ1 induces tumor regression of AR-amplified human CRPC in a xenograft mouse model. Together, we demonstrate that CDK7 inhibition selectively targets MED1-mediated, AR-dependent oncogenic transcriptional amplification, thus representing a potential new approach for the treatment of CRPC. SIGNIFICANCE: Potent inhibition of AR signaling is critical to treat CRPC. This study uncovers a driver role for CDK7 in regulating AR-mediated transcription through phosphorylation of MED1, thus revealing a therapeutically targetable potential vulnerability in AR-addicted CRPC.See related commentary by Russo et al., p. 1490.This article is highlighted in the In This Issue feature, p. 1469.

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.