Mitochondrial translation deficiency impairs NAD+ -mediated lysosomal acidification.

Mitochondrial translation dysfunction is associated with neurodegenerative and cardiovascular diseases. Cells eliminate defective mitochondria by the lysosomal machinery via autophagy. The relationship between mitochondrial translation and lysosomal function is unknown. In this study, mitochondrial translation-deficient hearts from p32-knockout mice were found to exhibit enlarged lysosomes containing lipofuscin, suggesting impaired lysosome and autolysosome function. These mice also displayed autophagic abnormalities, such as p62 accumulation and LC3 localization around broken mitochondria. The expression of genes encoding for nicotinamide adenine dinucleotide (NAD+ ) biosynthetic enzymes-Nmnat3 and Nampt-and NAD+ levels were decreased, suggesting that NAD+ is essential for maintaining lysosomal acidification. Conversely, nicotinamide mononucleotide (NMN) administration or Nmnat3 overexpression rescued lysosomal acidification. Nmnat3 gene expression is suppressed by HIF1α, a transcription factor that is stabilized by mitochondrial translation dysfunction, suggesting that HIF1α-Nmnat3-mediated NAD+ production is important for lysosomal function. The glycolytic enzymes GAPDH and PGK1 were found associated with lysosomal vesicles, and NAD+ was required for ATP production around lysosomal vesicles. Thus, we conclude that NAD+ content affected by mitochondrial dysfunction is essential for lysosomal maintenance.

Mitochondrial haplotype mutation alleviates respiratory defect of MELAS by restoring taurine modification in tRNA with 3243A > G mutation.

The 3243A > G in mtDNA is a representative mutation in mitochondrial diseases. Mitochondrial protein synthesis is impaired due to decoding disorder caused by severe reduction of 5-taurinomethyluridine (τm5U) modification of the mutant mt-tRNALeu(UUR) bearing 3243A > G mutation. The 3243A > G heteroplasmy in peripheral blood reportedly decreases exponentially with age. Here, we found three cases with mild respiratory symptoms despite bearing high rate of 3243A > G mutation (>90%) in blood mtDNA. These patients had the 3290T > C haplotypic mutation in addition to 3243A > G pathogenic mutation in mt-tRNALeu(UUR) gene. We generated cybrid cells of these cases to examine the effects of the 3290T > C mutation on mitochondrial function and found that 3290T > C mutation improved mitochondrial translation, formation of respiratory chain complex, and oxygen consumption rate of pathogenic cells associated with 3243A > G mutation. We measured τm5U frequency of mt-tRNALeu(UUR) with 3243A > G mutation in the cybrids by a primer extension method assisted with chemical derivatization of τm5U, showing that hypomodification of τm5U was significantly restored by the 3290T > C haplotypic mutation. We concluded that the 3290T > C is a haplotypic mutation that suppresses respiratory deficiency of mitochondrial disease by restoring hypomodified τm5U in mt-tRNALeu(UUR) with 3243A > G mutation, implying a potential therapeutic measure for mitochondrial disease associated with pathogenic mutations in mt-tRNAs.

Pyrophosphate detection method using 5-Br-PAPS to detect nucleic acid amplification - Application to LAMP method.

Genetic testing has been increasingly used in several fields. In many applications, nucleic acid amplification technology is required. However, current methods to detect nucleic acid amplification require expensive reagents and special equipment or exhibit limited sensitivity, which hinders their use. To address this issue, this study reports an assay method for detecting occurrence of acid amplification in post-amplification samples using pyrophosphate, a highly sensitive byproduct of nucleic acid amplification. The method proposed requires two reagents and an automated analyzer. First, hydrogen peroxide is derived from pyrophosphate, an indicator of nucleic acid amplification, and the oxidizing power of hydrogen peroxide is used to produce Fe (III) from Fe (II). The specific metal chelator 5-Br-PAPS forms a complex with the trivalent iron produced, resulting in a highly sensitive coloration. The within-run reproducibility of our method (n = 20) was less than 3.67% at each concentration tested, and the detection limit was 0.075 µmol/L, sufficient for quantitative analysis. The technique described could detect pyrophosphate in a sample that was amplified using the loop-mediated isothermal amplification method after only 10 min. Therefore, the proposed method has the potential to be a new, rapid, and simple detection technique for amplified nucleic acids.

The clinical and genetic landscape of early-onset thrombophilia in Japan.

OBJECTIVES: To determine the optimal management for early-onset thrombophilia (EOT), the genetic and clinical features of protein C (PC)-, protein S (PS)-, or antithrombin (AT)-deficient patients of ≤20 years of age were studied in Japan. METHODS/RESULTS: Clinical and genetic information of all genetically diagnosed cases was collected through the prospective, retrospective study, and literature review. One-hundred-one patients had PC (n = 55), PS (n = 29), or AT deficiency (n = 18). One overlapping case had PC- and PS-monoallelic variant. Fifty-five PC-deficient patients (54%) had 26 monoallelic or 29 biallelic variant(s), and 29 (29%) PS-deficient patients had 20 monoallelic or nine biallelic variant(s). None of the patients had AT-biallelic variants. The frequent low-risk allele p.K193del (PC-Tottori) was found in five patients with monoallelic (19%) but not 29 with biallelic variant(s). The most common low-risk allele p.K196E (PS-Tokushima) was found in five with monoallelic (25%) and six with biallelic variant(s) (67%). One exceptional de novo PC variant was found in 32 families with EOT. Only five parents had a history of thromboembolism. Thrombosis concurrently developed in three mother-newborn pairs (two PC deficiency and one AT deficiency). The prospective cohort revealed the outcomes of 35 patients: three deaths with PC deficiency and 20 complication-free survivors. Neurological complications were more frequently found in patients with PC-biallelic variants than those with PC-, PS-, or AT-monoallelic variants (73% vs. 24%, p = .019). CONCLUSIONS: We demonstrate the need for elective screening for EOT targeting PC deficiency in Japan. Early prenatal diagnosis of PC deficiency in mother-infant pairs may prevent perinatal thrombosis in them.

[Genetic predisposition to early-onset thrombophilia: a study on challenges in personalized medicine for mothers, infants, and children].

The number of reports on genetic predisposition to pediatric thrombosis is increasing. The risk of thrombosis in childhood varies according to patient age, and the contribution of genetic predisposition also differs. The term early-onset thrombophilia, which occurs until the age of 20 years in patients with genetic diagnosis, was defined. Then, the registry in Japan was established. Further, publications were reviewed comprehensively, and results revealed the genetic and clinical characteristics of patients. Less than 60% of patients presented with protein C (PC) deficiency, and over half of them had PC-gene monoallelic variants. The number of patients with protein S or antithrombin deficiency increased with age. None of them were aged between 6 and 8 years. PC-Tottori and protein S-Tokushima, which are high-frequency and low-risk variants in Japanese, contributed to the development of thrombosis. However, PC-Tottori did not affect the development of severe PC deficiency. One exceptional de novo PC-deficient variant was identified in 32 EOT families, and thrombosis developed concurrently in three pairs of mothers-newborns. Appropriate EOT screening tests targeting PC deficiency are required to prevent maternal and neonatal thromboses.

Extracellular vesicles expressing CEACAM proteins in the urine of bladder cancer patients.

Early detection and long-term monitoring are important for urothelial carcinoma of the bladder (UCB). Urine cytology and existing markers have insufficient diagnostic performance. Here, we examined medium-sized extracellular vesicles (EVs) in urine to identify specific markers for UCB and evaluated their usefulness as diagnostic material. To identify specific markers in urinary EVs derived from UCB, we undertook shotgun proteomics using urine from four UCB patients and four healthy subjects. Next, 29 healthy specimens, 18 noncancer specimens, and 33 UCB specimens, all from men, were analyzed for urinary EVs by flow cytometry to evaluate the diagnostic performance of UCB-specific EVs. Nanoparticle-tracking analysis indicated that the size of EVs extracted from urine was mostly <400 nm. By shotgun proteomics, we detected several proteins characteristic of UCB and found that carcinoembryonic antigen-related adhesion molecule (CEACAM) proteins were increased in patients. Flow cytometric analysis revealed that the degree of expression of CEACAM1, CEACAM5, and CEACAM6 proteins on the surface of EVs varied among patients. Extracellular vesicles expressing CEACAM proteins also expressed mucin 1, suggesting that they were derived from tumorigenic uroepithelial cells. The number of EVs expressing CEACAM1, 5, and 6 proteins was significantly increased in UCB (mean ± SD, 8.6 ± 13%) compared to non-UCB (0.69 ± 0.46) and healthy (0.46 ± 0.34) by flow cytometry. The results of receiver operating characteristic (ROC) analysis showed a good score of area under the ROC curve of 0.907. We identified EVs that specifically express CEACAM proteins in urine and have potential for diagnostic applications. These EVs are potential targets in a new liquid biopsy test for UCB patients.

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.

Gene amplification of YB-1 in castration-resistant prostate cancer in association with aberrant androgen receptor expression.

Although Y-box binding protein-1 (YB-1) is known to be overexpressed in prostate cancer, especially castration-resistant prostate cancer (CRPC), the mechanism of its overexpression remains unclear. We aimed to elucidate the mechanism of YB-1 overexpression in CRPC. Gene amplification in CRPC cells and tissues was examined by public database analysis, and digital PCR. The significance of YB-1 amplification for the YB-1/androgen receptor (AR) axis and prognosis was examined by public database analysis and immunohistochemistry. YB-1 amplification was mainly observed in CRPC tissues by public database analysis and confirmed in CRPC cells and tissues by digital PCR. Expression of YB-1 was increased in CRPC tissues compared with treatment-naïve tissues. Furthermore, YB-1 and phosphorylated YB-1 levels were associated with AR and AR V7 expression levels. Finally, YB-1 amplification was associated with poor outcomes in CRPC. Taken together, the present findings suggest that YB-1 amplification contributes to progression to CRPC through regulation of AR and AR V7 expressions, and that YB-1 is a promising therapeutic target in CRPC.

Within-host evolution of a Klebsiella pneumoniae clone: selected mutations associated with the alteration of outer membrane protein expression conferred multidrug resistance.

BACKGROUND: A patient repeatedly developed bacteraemia despite the continuous use of antibiotics. We obtained two Klebsiella pneumoniae isolates from the patient's blood on Days 72 and 105 after hospitalization. Each of the two isolates belonged to ST45, but while the first isolate was susceptible to most antibiotics, the second one was resistant to multiple drugs including carbapenems. OBJECTIVES: To identify the genetic differences between the two isolates and uncover alterations formed by the within-host bacterial evolution leading to the antimicrobial resistance. METHODS: Whole-genome comparison of the two isolates was carried out to identify their genetic differences. We then profiled their outer membrane proteins related to membrane permeability to drugs. To characterize a ramR gene mutation found in the MDR isolate, its WT and mutant genes were cloned and expressed in the MDR isolate. RESULTS: The two isolates showed only three genomic differences, located in mdoH, ramR and upstream of ompK36. In the MDR isolate, a single nucleotide substitution in the ompK36 upstream region attenuated OmpK36 expression. A single amino acid residue insertion in RamR in the MDR isolate impaired its function, leading to the down-regulation of OmpK35 and the subsequent up-regulation of the AcrAB-TolC transporter, which may contribute to the MDR. CONCLUSIONS: We identified very limited genomic changes in the second K. pneumoniae clone during within-host evolution, but two of the three identified mutations conferred the MDR phenotype on the clone by modulating drug permeability.

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

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

Clinical Impact of Heritable Thrombophilia on Neonatal-Onset Thromboembolism: A Nationwide Study in Japan.

OBJECTIVE: To clarify the incidence and genetic risk of neonatal-thromboembolism, we conducted a nationwide study exploring the impact of thrombophilia on neonatal-thromboembolism in Japan. STUDY DESIGN: A questionnaire survey was conducted for perinatal centers in Japan, focusing on the clinical expression, genotype, treatment, and outcome of patients who developed thromboembolism within 28 days of birth from 2014 to 2018. RESULTS: The estimated incidence of neonatal-thromboembolism was 0.39 cases per 10 000 live births. Intracranial lesions and purpura fulminans occurred in 66 and 5 of 77 patients, respectively. Fifty-eight (75.3%) infants presented within 3 days after birth. Four (5.2%) died, and 14 (18.2%) survived with disability. At the diagnosis, <20% plasma activity of protein C was noted in 16 infants, protein S (in 2), and antithrombin (in 1). Thirteen genetic tests identified 4 biallelic and 5 monoallelic protein C-variants but no protein S- or antithrombin-variants. Protein C-variants had purpura fulminans (P < .01), ocular bleeding (P < .01), positive-family history (P = .01), and death or disability (P = .03) more frequently than others. Protein C-variants were independently associated with disability (OR 5.74, 95% CI 1.16-28.4, P = .03) but not death. Four biallelic variants had serious thrombotic complications of neurologic disability, blindness, and/or amputation. Three monoallelic variants survived without complications. The only protein C-variant death was an extremely preterm heterozygote infant. CONCLUSIONS: Monoallelic protein C-variants had a higher incidence of neonatal-thromboembolism than biallelic variants. Thrombophilia genetic testing should be performed in the setting of neonatal-thromboembolism and low protein C to identify the underlying genetic defect.

Development of a protein assay with copper chelator chromeazurol B, based on the biuret reaction.

This study aimed to provide a novel and highly sensitive protein assay based on the biuret reaction and using chromeazurol B, a metal chelate compound. The method consists of two reagents and an automated analyzer. First, a complex of copper and protein (biuret reaction) is formed. Second, a chelating reagent containing chromeazurol B forms a three-dimensional complex of protein, copper, and chromeazurol B at neutral pH, resulting in highly sensitive coloration. The intra-assay (n = 20) variation for the three levels was 3.54 % or lower at each concentration. Each response with α, ß-, and γ-globulin was 103.8 % and 104.3 %, respectively, against albumin. The molar absorption coefficient (ε) of the present method was 2.5 × 105 m2/mol against human albumin, higher than that of the commercially available Lowry method (ε = 8.7 × 104 m2/mol), which is based on the same principle. The correlation test for the pyrogallol method with 30 urine samples showed good performance (r = 0.961). The method described here (the Biuret-based CAB method) is a more sensitive and rapid assay than the Lowry method, and it may also be applied to biological samples because of its similar reactivity towards various proteins.

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

OBJECTIVE: To investigate the somatic mutation profiles of testicular germ cell tumors in Japanese men. METHODS: We analyzed the somatic missense mutation profile of testicular germ cell tumors among 21 Japanese men with seminoma (n = 14), pure embryonic carcinoma (n = 3) and mixed testicular germ cell tumor (n = 4) by targeted next-generation sequencing of 409 cancer-related genes covering 1.23 Mb of the genome. RESULTS: We identified a total of 22 missense mutations in 21 primary testicular germ cell tumor samples (0.89 mutations/Mb), of which seven mutations were confirmed to be absent from the germline. KIT:p.Asn822Tyr, KIT:p.Leu576Pro, PIK3CA:p.Glu542Lys and FBXW7:p.Arg505His were statistically and functionally potential. A total of 18 missense mutations were previously unknown in testicular germ cell tumors. PDGFRA amplification from one patient with seminoma was detected. KIT, BCR,PIK3CG, PIK3CA and PDGFRA mutations involved in aberrant signaling of the KIT-PI3K-AKT pathway was detected in 27.3% of detected mutations. CONCLUSIONS: The present investigation identified a low mutation rate in testicular germ cell tumors among Asian patients, 18 novel mutations and PDGFRA amplification. Limitations of the present study are the small sample and missing normal DNA for some testicular germ cell tumors.

High-throughput screen identifies 5-HT receptor as a modulator of AR and a therapeutic target for prostate cancer.

BACKGROUND: Eradication of persistent androgen receptor (AR) activity in castration-resistant prostate cancer may be a promising strategy to overcome castration resistance. We aimed to identify novel compounds that inhibit AR activity and could be potential therapeutic agents for prostate cancer. METHODS: A high-throughput screening system involving cell lines stably expressing AR protein and AR-responsive luciferase was employed for the 1260 compound library. Molecular and antitumor effects on candidate pathways that interacted with AR signaling were examined in prostate cancer cells expressing AR. RESULTS: The high-throughput screening identified various potential compounds that interfered with AR signaling through known and novel pathways. Among them, a 5-hydroxytryptamine 5A (5-HT5A) receptor antagonist suppressed AR activity through protein kinase A signaling, which was confirmed by 5-HT5A receptor knockdown. Consistently, 5-HT5A receptor inhibitors showed cytotoxic effects toward prostate cancer cells. CONCLUSIONS: Taken together, this study identifies 5-HT5A receptor as a promising therapeutic target for prostate cancer via its interaction with AR signaling.

Biallelic C1QBP Mutations Cause Severe Neonatal-, Childhood-, or Later-Onset Cardiomyopathy Associated with Combined Respiratory-Chain Deficiencies.

Complement component 1 Q subcomponent-binding protein (C1QBP; also known as p32) is a multi-compartmental protein whose precise function remains unknown. It is an evolutionary conserved multifunctional protein localized primarily in the mitochondrial matrix and has roles in inflammation and infection processes, mitochondrial ribosome biogenesis, and regulation of apoptosis and nuclear transcription. It has an N-terminal mitochondrial targeting peptide that is proteolytically processed after import into the mitochondrial matrix, where it forms a homotrimeric complex organized in a doughnut-shaped structure. Although C1QBP has been reported to exert pleiotropic effects on many cellular processes, we report here four individuals from unrelated families where biallelic mutations in C1QBP cause a defect in mitochondrial energy metabolism. Infants presented with cardiomyopathy accompanied by multisystemic involvement (liver, kidney, and brain), and children and adults presented with myopathy and progressive external ophthalmoplegia. Multiple mitochondrial respiratory-chain defects, associated with the accumulation of multiple deletions of mitochondrial DNA in the later-onset myopathic cases, were identified in all affected individuals. Steady-state C1QBP levels were decreased in all individuals' samples, leading to combined respiratory-chain enzyme deficiency of complexes I, III, and IV. C1qbp-/- mouse embryonic fibroblasts (MEFs) resembled the human disease phenotype by showing multiple defects in oxidative phosphorylation (OXPHOS). Complementation with wild-type, but not mutagenized, C1qbp restored OXPHOS protein levels and mitochondrial enzyme activities in C1qbp-/- MEFs. C1QBP deficiency represents an important mitochondrial disorder associated with a clinical spectrum ranging from infantile lactic acidosis to childhood (cardio)myopathy and late-onset progressive external ophthalmoplegia.

Genome-wide association study of genetic variations associated with treatment failure after intravesical bacillus Calmette-Guérin therapy for non-muscle invasive bladder cancer.

Bacillus Calmette-Guérin (BCG) instillation is a key therapy to manage non-muscle invasive bladder cancer (NMIBC). However, intravesical BCG therapy fails in approximately half of the patients, leading to recurrence and progression. We aimed to reveal the genetic variations associated with treatment failure after intravesical BCG therapy for NMIBC. This study included 91 Japanese patients treated with BCG instillation for NMIBC. Genomic DNA was obtained from patient whole-blood samples, and a genome-wide association study and genotyping for target regions were performed. The association between genetic variation and treatment failure was analyzed by genome-wide association in 44 patients as the discovery cohort. As a validation study, candidate single nucleotide polymorphisms (SNPs) were examined among 47 patients in another cohort. The genome-wide association study indicated 19 candidate SNPs (rs1607282, rs7825442, rs1319325, rs3738088, rs4250, rs11894207, rs161448, rs2764326, rs2814707, rs3787194, rs58081719, rs3095966, rs73520681, rs16877113, rs16887173, rs10269584, rs11772249, rs118137814, and rs61094339) associated with BCG failure. Following the cumulative analysis of candidate SNPs, 2-gene (rs73520681 and rs61094339) and 4-gene (rs4250, rs11894207, rs73520681, and rs61094339) models successfully predicted treatment failure after intravesical BCG therapy. This study showed that several SNPs were possibly associated with outcome after intravesical BCG therapy in a Japanese population with NMIBC. The cumulative models of these SNPs may have value in clinical applications, although this should be confirmed in future studies.

Toxic myopathy with multiple deletions in mitochondrial DNA associated with long-term use of oral anti-viral drugs for hepatitis B: A case study.

Oral nucleoside analogs (NAs) reduce hepatitis B virus (HBV) replication by inhibiting HBV DNA polymerase. However, NAs can also affect human mitochondrial DNA (mtDNA) polymerase, which can lead to mtDNA depletion (quantitative abnormality). Indeed, several mitochondrial myopathy cases have been reported in which a reduced mtDNA copy number was induced by oral NAs for hepatitis B. Herein, we report a case of toxic myopathy with multiple mtDNA deletions (qualitative abnormality) associated with long-term use of NAs for hepatitis B. A 68-year-old woman, who underwent long-term treatment with lamivudine and adefovir for chronic hepatitis B, developed proximal muscle weakness in the four extremities. Neurological examination showed mild proximal muscle weakness and atrophy in the four extremities. Upon admission to our hospital, her blood lactate/pyruvate ratio during an aerobic exercise test was elevated. Myogenic patterns were observed in lower limb muscles on electromyographic examination. Muscle magnetic resonance imaging revealed diffuse atrophy of proximal muscles in the four extremities with no signal changes. A biopsy from the biceps brachii muscle showed an abnormally large variation in fiber size, scattered muscle fibers with decreased cytochrome c oxidase activity, and ragged-red fibers. Analysis of mtDNA from skeletal muscle revealed no decrease in copy number but increased incidence of multiple deletions, including a deletion of 4977 base pairs (known as the common deletion) reflecting oxidative stress-induced mtDNA damage. This case study indicates that long-term oral antiviral therapy for hepatitis B can induce chronic oxidative damage to mtDNA resulting in qualitative mtDNA abnormalities and toxic myopathy.

Collateral resistance to taxanes in enzalutamide-resistant prostate cancer through aberrant androgen receptor and its variants.

Currently, the optimal sequential use of androgen receptor (AR) axis-targeted agents and taxane chemotherapies remains undetermined. We aimed to elucidate the resistance status between taxanes and enzalutamide, and the functional role of the AR axis. Enzalutamide-resistant 22Rv1 cells showed collateral resistance to taxanes, including docetaxel and cabazitaxel. However, taxane-resistant cells showed no collateral resistance to enzalutamide; taxane-resistant cells expressed comparable protein levels of full-length AR and AR variants. Knockdown of both full-length AR and AR variants rendered cells sensitive to taxanes, whereas knockdown of AR variants sensitized cells to enzalutamide, but not to taxanes. In contrast, overexpression of full-length AR rendered cells resistant to taxanes. Consistently, the prostate-specific antigen response and progression-free survival in docetaxel chemotherapy were worse in cases with prior use of ARAT agents compared with cases without. Collateral resistance to taxanes was evident after obtaining enzalutamide resistance, and aberrant AR signaling might be involved in taxane resistance.

Mineralocorticoid receptor signaling affects therapeutic effect of enzalutamide.

BACKGROUND: Corticosteroids play important roles in prostate cancer therapeutics. However, their role when combined with enzalutamide remains obscure. Then, we aimed to elucidate the functional and clinical impact of corticosteroids on steroid receptors in androgen receptor (AR)-targeting therapy utilizing enzalutamide. METHODS: The therapeutic effect was studied according to concomitant use of corticosteroids in 86 men treated with enzalutamide. The sensitivity to various agents was evaluated using cytotoxicity assays in prostate cancer cells. Gene expression levels were evaluated by quantitative real-time polymerase chain reaction in prostate cancer cells and tissues. RESULTS: The therapeutic effect of enzalutamide was particularly lessened with concomitant treatment with dexamethasone. Consistently, dexamethasone increased cellular resistance to enzalutamide while prednisolone and aldosterone decreased cellular resistance to enzalutamide in prostate cancer cells. Inversely, mineralocorticoid receptor (MR) knockdown augmented the activity of AR signaling and the cellular resistance to enzalutamide. CONCLUSIONS: MR plays a critical role in resistance to AR-targeting therapies, which may be overcome by activation of MR signaling.

The Association of Polymorphisms in the Gene Encoding Gonadotropin-Releasing Hormone with Serum Testosterone Level during Androgen Deprivation Therapy and Prognosis of Metastatic Prostate Cancer.

PURPOSE: Serum testosterone suppression during androgen deprivation therapy has been reported to affect the efficacy of androgen deprivation therapy. However, the factors impacting hormonal variations during androgen deprivation therapy remain unclear. Therefore, in this study we investigated the significance of missense polymorphisms in the gene encoding GNRH in men treated with primary androgen deprivation therapy for metastatic prostate cancer. MATERIALS AND METHODS: This study included 80 Japanese patients with metastatic prostate cancer with available serum testosterone levels during androgen deprivation therapy. We examined the association of GNRH1 (rs6185, S20W) and GNRH2 (rs6051545, A16V) gene polymorphisms with clinicopathological parameters, including serum testosterone levels during androgen deprivation therapy, as well as prognosis, including progression-free and overall survival. RESULTS: The CT and CT/TT alleles in the GNRH2 gene (rs6051545) were associated with higher serum testosterone during androgen deprivation therapy compared with those of the CC allele. Consequently the CT alleles were associated with a higher risk of progression after adjustment for age and serum testosterone during androgen deprivation therapy (HR 1.73, 95% CI 1.00-3.00, p = 0.049). CONCLUSIONS: Taken together these findings suggest that rs6051545 (GNRH2) genetic variation may result in inadequate suppression of serum testosterone during androgen deprivation therapy. This may lead to detrimental effects of androgen deprivation therapy on prognosis in men with metastatic prostate cancer.