Epigenetic susceptibility factors for prostate cancer with aging

α-lipoic acid modulates prostate cancer cell growth and bone cell differentiation

Prostate cancer (PCa) progression leads to bone modulation in approximately 70% of affected men. A nutraceutical, namely, α-lipoic acid (α-LA), is known for its potent anti-cancer properties towards various cancers and has been implicated in treating and promoting bone health. Our study aimed to explore the molecular mechanism behind the role of α-LA as therapeutics in preventing PCa and its associated bone modulation. Notably, α-LA treatment significantly reduced the cell viability, migration, and invasion of PCa cell lines in a dose-dependent manner. In addition, α-LA supplementation dramatically increased reactive oxygen species (ROS) levels and HIF-1α expression, which started the downstream molecular cascade and activated JNK/caspase-3 signaling pathway. Flow cytometry data revealed the arrest of the cell cycle in the S-phase, which has led to apoptosis of PCa cells. Furthermore, the results of ALP (Alkaline phosphatase) and TRAP (tartrate-resistant acid phosphatase) staining signifies that α-LA supplementation diminished the PCa-mediated differentiation of osteoblasts and osteoclasts, respectively, in the MC3T3-E1 and bone marrow macrophages (BMMs) cells. In summary, α-LA supplementation enhanced cellular apoptosis via increased ROS levels, HIF-1α expression, and JNK/caspase-3 signaling pathway in advanced human PCa cell lines. Also, the treatment of α-LA improved bone health by reducing PCa-mediated bone cell modulation.

PCMT1 regulates the migration, invasion, and apoptosis of prostate cancer through modulating the PI3K/AKT/GSK-3β pathway

Protein L-isoaspartate (D-aspartate) O-methyltransferase (PCMT1) is a repair enzyme that catalyzes the conversion of isomerized aspartic acid (iso-Asp) residues into their normal structure, thereby restoring the configuration and function of proteins. Studies have shown that PCMT1 is overexpressed in several tumors and affects patients' prognosis. However, there are few reports on the role of PCMT1 in prostate cancer (PCa). In the present research, with the assistance of The Cancer Genome Atlas Program (TCGA) database, we found that PCMT1 was overexpressed in PCa tissues. The results of quantitative reverse transcription-polymerase chain reaction (qRT-PCR), western blot and immunohistochemistry staining also showed that PCMT1 expression was significantly increased in PCa tissues and cell lines. In PCa clinical samples, PCMT1 expression was closely related to Gleason score, clinical stage, lymph node metastasis and bone metastasis. The experiments of overexpression and knockdown of PCMT1 in vitro or in vivo showed that PCMT1 can significantly promote the proliferation, migration and invasion of PCa cells, inhibit cell apoptosis, and promote the growth of PCa. We furthermore confirmed that PCMT1 regulated the migration, invasion and apoptosis of PCa cells by modulating the phosphatidylinositol 3-kinase/AKT kinase/glycogen-synthase kinase-3β (PI3K/AKT/GSK-3β) signaling pathway. Collectively, PCMT1 plays a cancer-facilitative role in PCa by promoting the proliferation, migration and invasion of PCa cells, and inhibiting apoptosis. Therefore, PCMT1 is considered to represent a novel target for treating PCa.

The Potential Role of Mitochondrial Acetaldehyde Dehydrogenase 2 in Urological Cancers From the Perspective of Ferroptosis and Cellular Senescence

Overproduction of reactive oxygen species (ROS) and superlative lipid peroxidation promote tumorigenesis, and mitochondrial aldehyde dehydrogenase 2 (ALDH2) is associated with the detoxification of ROS-mediated lipid peroxidation-generated reactive aldehydes such as 4-hydroxy-2-nonenal (4-HNE), malondialdehyde, and acrolein due to tobacco smoking. ALDH2 has been demonstrated to be highly associated with the prognosis and chemoradiotherapy sensitivity of many types of cancer, including leukemia, lung cancer, head and neck cancer, esophageal cancer, hepatocellular cancer, pancreatic cancer, and ovarian cancer. In this study, we explored the possible relationship between ALDH2 and urological cancers from the aspects of ferroptosis, epigenetic alterations, proteostasis, mitochondrial dysfunction, and cellular senescence.

The Interplay Between Prostate Cancer Genomics, Metabolism, and the Epigenome: Perspectives and Future Prospects

Prostate cancer is a high-incidence cancer, often detected late in life. The prostate gland is an accessory gland that secretes citrate; an impaired citrate secretion reflects imbalances in the activity of enzymes in the TCA Cycle in mitochondria. Profiling studies on prostate tumours have identified significant metabolite, proteomic, and transcriptional modulations with an increased mitochondrial metabolic activity associated with localised prostate cancer. Here, we focus on the androgen receptor, c-Myc, phosphatase and tensin Homolog deleted on chromosome 10 (PTEN), and p53 as amongst the best-characterised genomic drivers of prostate cancer implicated in metabolic dysregulation and prostate cancer progression. We outline their impact on metabolic function before discussing how this may affect metabolite pools and in turn chromatin structure and the epigenome. We reflect on some recent literature indicating that mitochondrial mutations and OGlcNAcylation may also contribute to this crosstalk. Finally, we discuss the technological challenges of assessing crosstalk given the significant differences in the spatial sensitivity and throughput of genomic and metabolomic profiling approaches.

Association of Age With Risk of Adverse Pathological Findings in Men Undergoing Delayed Radical Prostatectomy Following Active Surveillance

OBJECTIVES

To determine if older men with Gleason grade group (GG) 1 prostate cancer have a higher risk of having adverse pathology at radical prostatectomy after initially being managed with active surveillance (AS).

METHODS

A total of 365 patients with GG1 prostate cancer initially managed with AS followed by delayed radical prostatectomy were identified. The primary outcome was adverse pathology after delayed radical prostatectomy in the men that were <65 years vs. men ≥65 years at the initiation of AS. Adverse pathology was defined as GG ≥3 or pT3 or pN1. Multivariable Cox proportional hazards regression models were used to calculate risk of adverse pathological findings at radical prostatectomy by age group.

RESULTS

At diagnosis, there were no significant differences in median prostate specific antigen density, percent positive biopsy cores, multiparametric magnetic resonance imaging (mpMRI) results or composite genomic classifier scores (derived from three commercially available genomic tests) between the two age groups. Men ≥65 years had more adverse pathology at radical prostatectomy (59.2% vs. 44.1%, P <0.01) and lower rates of biopsy upgrade-free survival and adverse pathology-free survival (log-rank P <0.01). On multivariable analysis age ≥65 years (Hazard Ratio (HR) 2.21, 95% Confidence Interval (CI) 1.57, 3.12) was associated with adverse pathology at radical prostatectomy. In separate multivariable analyses done for each age group, mpMRI (HR 3.33, 95% CI 1.01, 10.95) was predictor of adverse pathology in the group ≥65 years.

CONCLUSION

Older patients might require closer monitoring on AS and additional testing such as mpMRI might improve their risk stratification.

Epigenomic regulation of human T-cell leukemia virus by chromatin-insulator CTCF

Human T-cell leukemia virus type 1 (HTLV-1) is a retrovirus that causes an aggressive T-cell malignancy and a variety of inflammatory conditions. The integrated provirus includes a single binding site for the epigenomic insulator, CCCTC-binding protein (CTCF), but its function remains unclear. In the current study, a mutant virus was examined that eliminates the CTCF-binding site. The mutation did not disrupt the kinetics and levels of virus gene expression, or establishment of or reactivation from latency. However, the mutation disrupted the epigenetic barrier function, resulting in enhanced DNA CpG methylation downstream of the CTCF binding site on both strands of the integrated provirus and H3K4Me3, H3K36Me3, and H3K27Me3 chromatin modifications both up- and downstream of the site. A majority of clonal cell lines infected with wild type HTLV-1 exhibited increased plus strand gene expression with CTCF knockdown, while expression in mutant HTLV-1 clonal lines was unaffected. These findings indicate that CTCF binding regulates HTLV-1 gene expression, DNA and histone methylation in an integration site dependent fashion.

Human T-cell leukemia virus type 1 (HTLV-1) is a cause of leukemia and lymphoma as well as several inflammatory medical disorders. The virus integrates in the host cell DNA, and it has a single binding site for a protein designated CTCF. This protein is important in the regulation of many DNA viruses, as well as many properties of normal and malignant cells. In order to define the role of CTCF binding to HTLV, we analyzed a mutant virus lacking the binding site. We found that this mutation variably affected gene expression, DNA and histone modification, suggesting a key role in regulation of virus replication in infected cells.

RNAM EXPRESSION AND DNA METHYLATION OF DKK2 GENE IN COLORECTAL CÂNCER

BACKGROUND

Colorectal cancer is the third most common neoplasm in the world. Methylation of tumor related genes in CpG islands can cause gene silencing and been involved in the development of cancer. The potential role of DKK2 as a biomarker for early diagnosis of colorectal cancer remains unclear.

OBJECTIVE

The aim of the study was to evaluate the profile of methylation and RNAm expression of DKK2 as potential predictors of colorectal cancer diagnosis and prognosis.

METHODS

Expression of mRNAs encoding DKK2 in 35 colorectal cancer tissues was quantified using real-time polymerase chain reaction analysis. The DNA methylation was studied by high resolution melting analysis. The general characteristics of the patients were collected. DKK2 methylation and expression were compared to clinical, pathological aspects and overall survival.

RESULTS

Among the 35 patients studied, 18 were male, 10 were on right colon and 25 on left colon. Among the 20 patients with high hypermethylation, 15 of them had mRNA low expression of DKK2. There was no significant association between DKK2 promoter methylation and mRNA DKK2 expression and clinical or pathological features. DKK2 promoter methylation (P=0.154) and DKK2 RNA expression (P=0.345) did not show significant correlation with overall survival.

CONCLUSION

DKK2 promoter methylation and DKK2 RNA status appear to be biomarkers of cancer diagnosis but not predictors of prognosis.

Elucidation of the Genomic-Epigenomic Interaction Landscape of Aggressive Prostate Cancer

Background

Majority of prostate cancer (PCa) deaths are attributed to localized high-grade aggressive tumours which progress rapidly to metastatic disease. A critical unmet need in clinical management of PCa is discovery and characterization of the molecular drivers of aggressive tumours. The development and progression of aggressive PCa involve genetic and epigenetic alterations occurring in the germline, somatic (tumour), and epigenomes. To date, interactions between genes containing germline, somatic, and epigenetic mutations in aggressive PCa have not been characterized. The objective of this investigation was to elucidate the genomic-epigenomic interaction landscape in aggressive PCa to identify potential drivers aggressive PCa and the pathways they control. We hypothesized that aggressive PCa originates from a complex interplay between genomic (both germline and somatic mutations) and epigenomic alterations. We further hypothesized that these complex arrays of interacting genomic and epigenomic factors affect gene expression, molecular networks, and signaling pathways which in turn drive aggressive PCa.

Methods

We addressed these hypotheses by performing integrative data analysis combining information on germline mutations from genome-wide association studies with somatic and epigenetic mutations from The Cancer Genome Atlas using gene expression as the intermediate phenotype.

Results

The investigation revealed signatures of genes containing germline, somatic, and epigenetic mutations associated with aggressive PCa. Aberrant DNA methylation had effect on gene expression. In addition, the investigation revealed molecular networks and signalling pathways enriched for germline, somatic, and epigenetic mutations including the STAT3, PTEN, PCa, ATM, AR, and P53 signalling pathways implicated in aggressive PCa.

Conclusions

The study demonstrated that integrative analysis combining diverse omics data is a powerful approach for the discovery of potential clinically actionable biomarkers, therapeutic targets, and elucidation of oncogenic interactions between genomic and epigenomic alterations in aggressive PCa.

CTCF loss mediates unique DNA hypermethylation landscapes in human cancers

Background

The chromatin insulator CCCTC-binding factor (CTCF) displays tissue-specific DNA binding sites that regulate transcription and chromatin organization. Despite evidence linking CTCF to the protection of epigenetic states through barrier insulation, the impact of CTCF loss on genome-wide DNA methylation sites in human cancer remains undefined.

Results

Here, we demonstrate that prostate and breast cancers within The Cancer Genome Atlas (TCGA) exhibit frequent copy number loss of CTCF and that this loss is associated with increased DNA methylation events that occur preferentially at CTCF binding sites. CTCF sites differ among tumor types and result in tissue-specific methylation patterns with little overlap between breast and prostate cancers. DNA methylation and transcriptome profiling in vitro establish that forced downregulation of CTCF leads to spatially distinct DNA hypermethylation surrounding CTCF binding sites, loss of CTCF binding, and decreased gene expression that is also seen in human tumors. DNA methylation inhibition reverses loss of expression at these CTCF-regulated genes.

Conclusion

These findings establish CTCF loss as a major mediator in directing localized DNA hypermethylation events in a tissue-specific fashion and further support its role as a driver of the cancer phenotype.

Validation of an epigenetic field of susceptibility to detect significant prostate cancer from non-tumor biopsies

Background

An epigenetic field of cancer susceptibility exists for prostate cancer (PC) that gives rise to multifocal disease in the peripheral prostate. In previous work, genome-wide DNA methylation profiling identified altered regions in the normal prostate tissue of men with PC. In the current multicenter study, we examined the predictive strength of a panel of loci to detect cancer presence and grade in patients with negative biopsy tissue.

Results

Four centers contributed benign prostate biopsy tissues blocks from 129 subjects that were either tumor associated (TA, Grade Group [GG] ≥ 2, n = 77) or non-tumor associated (NTA, n = 52). Biopsies were analyzed using pyrosequencing for DNA methylation encompassing CpG loci near CAV1, EVX1, FGF1, NCR2, PLA2G16, and SPAG4 and methylation differences were detected within all gene regions (p < 0.05). A multiplex regression model for biomarker performance incorporating a gene combination discriminated TA from NTA tissues (area under the curve [AUC] 0.747, p = 0.004). A multiplex model incorporating all the above genes and clinical information (PSA, age) identified patients with GG ≥ 2 PC (AUC 0.815, p < 0.0001). In patients with cancer, increased variation in gene methylation levels occurs between biopsies across the prostate.

Conclusions

A widespread epigenetic field defect is utilized to detect GG ≥ 2 PC in patients with histologically negative biopsies. These alterations in non-tumor cells display increased heterogeneity of methylation extent and are spatially distant from tumor foci. These findings have the potential to decrease the need for repeated prostate biopsy.

Markers as mediators: A review and synthesis of epigenetics literature

Epigenetics, the study of the processes that control gene expression without a change in DNA sequence, highlights the importance of environmental factors in gene regulation. This paper maps the terrain of epigenetics and identifies four main research subfields: gene expression; molecular epigenetics; clinical epigenetics and epigenetic epidemiology. Within and across these fields, we analyse of what is conceptualised as environment and demonstrate the variable ways authors understand epigenetics environments. Then, following an analysis of the discursive strategies employed by epigenetics researchers, we demonstrate how authors portray the interactions between genes, epigenetics, and environment as relationships linking the outside (where the environment is located) with the inside (where the genes are located). We argue that authors assign specific roles to each actor: the environment as the active player initiating the relationship, the genes as recipients, and epigenetics as mediators between environment and genes. Framed as mediators, epigenetic markers can be understood as enablers of communication between environment and genome, capable of processing and organising signals so as to regulate the interactions between the actors of epigenetic relationships. This finding complicates the observation by social science scholars that the interactions between environment and genes can be understood through the concept of signal.

CTCF regulates the FoxO signaling pathway to affect the progression of prostate cancer

The present research focuses on the influence of CCCTC‐binding factor (CTCF) on prostate cancer (PC) via the regulation of the FoxO signalling pathway. A bioinformatics analysis was conducted to screen out target genes for CTCF in LNCaP cells and to enrich the relevant pathways in LNCaP cells. It was found that the FoxO pathway was enriched according to the ChIP‐seq results of CTCF. The expression of CTCF, pFoxO1a, FoxO1a, pFoxO3a and FoxO3a was tested by RT‐qPCR and Western blot. Inhibition of CTCF could lead to the up‐regulation of the FoxO signalling pathway. The rates of cell proliferation, cell invasion and apoptosis were examined by MTT assay, cell invasion assay and flow cytometry under different interference conditions. Down‐regulation of CTCF could suppress cell proliferation, cell invasion and facilitate cell apoptosis. Lastly, the effect of CTCF on tumour growth was determined in nude mice. Inhibition of CTCF regulated the FoxO signalling pathway, which retarded tumour growth in vivo. In conclusion, CTCF regulates the FoxO signalling pathway to affect the progress of PC.

PAGE4 promotes prostate cancer cells survive under oxidative stress through modulating MAPK/JNK/ERK pathway

Background

Prostate cancer (PCa) is one of the most common cancers in male worldwide. Oxidative stress has been recognized as one of the driving signals pathologically linked to PCa progression. Nevertheless, the association of oxidative stress with PCa progression remains unclear.

Methods

Western blot, q-RT-PCR and bioinformatics analyses were used to examine PAGE4 expression. Comet assay and Annexin V/ PI dual staining assay were performed to investigate DNA damage and cell death under oxidative stress. Mouse xenograft model of PCa cells was established to verify the role of PAGE4 in vivo. Transcriptomic analysis was performed to investigate the underlying mechanism for the function of PAGE4 under oxidative stress. Western blot assay was conducted to determine the status of MAPK pathway. Immunohistochemistry was used to identify protein expression of PAGE4 in tumor tissues.

Results

In this study, we found that PAGE4 expression was increased in PCa cells under oxidative stress condition. PAGE4 overexpression protected PCa cells from oxidative stress-inducing cell death by reducing DNA damage. PAGE4 overexpression promoted PCa cells growth in vivo. Mechanistically, PAGE4 promoted the survival of prostate cancer cells through regulating MAPK pathway which reflected in decreasing the phosphorylation of MAP2K4, JNK and c-JUN but increasing phosphorylation of ERK1/2.

Conclusion

Our findings indicate that PAGE4 protects PCa cells from DNA damage and apoptosis under oxidative stress by modulating MAPK signalling pathway. PAGE4 expression may serve as a prognostic biomarker for clinical applications.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1032-3) contains supplementary material, which is available to authorized users.

Role of lncRNAs in aging and age-related diseases

Aging is progressive physiological degeneration and consequently declined function, which is linked to senescence on both cellular and organ levels. Accumulating studies indicate that long noncoding RNAs (lncRNAs) play important roles in cellular senescence at all levels-transcriptional, post-transcriptional, translational, and post-translational. Understanding the molecular mechanism of lncRNAs underlying senescence could facilitate interpretation and intervention of aging and age-related diseases. In this review, we describe categories of known and novel lncRNAs that have been involved in the progression of senescence. We also identify the lncRNAs implicated in diseases arising from age-driven degeneration or dysfunction in some representative organs and systems (brains, liver, muscle, cardiovascular system, bone pancreatic islets, and immune system). Improved comprehension of lncRNAs in the aging process on all levels, from cell to organismal, may provide new insights into the amelioration of age-related pathologies and prolonged healthspan.

Insulin-like growth factor 2 expression in prostate cancer is regulated by promoter-specific methylation

Deregulation of the insulin-like growth factor (IGF) axis and dysbalance of components of the IGF system as potential therapeutic targets have been described in different tumor types. IGF2 is a major embryonic growth factor and an important activator of IGF signaling. It is regulated by imprinting in a development- and tissue-dependent manner and has been implicated in a broad range of malignancies including prostate cancer (PCa). Loss of imprinting (LOI) usually results in bi-allelic gene expression and increased levels of IGF2. However, the regulatory mechanisms and the pathophysiological impact of altered IGF2 expression in PCa remain elusive. Here, we show that in contrast to many other tumors, IGF2 mRNA and protein levels were decreased in 80% of PCa in comparison with non-neoplastic adjacent prostate and were independent of LOI status. Instead, IGF2 expression in both tumors and adjacent prostate depended on preferential usage of the IGF2 promoters P3 and P4. Decreased IGF2 expression in tumors was strongly related to hypermethylation of these two promoters. Methylation of the A region in promoter P4 correlated specifically with IGF2 expression in the 20% of PCa where IGF2 was higher in tumors than in adjacent prostate. We conclude that IGF2 is downregulated in most PCa and may be particularly relevant during early stages of tumor development or during chemotherapy and androgen deprivation. PCa differs from other tumors in that IGF2 expression is mainly regulated through methylation of promoter-specific and not by imprinting. Targeting of promoter-specific regions may have relevance for the adjuvant treatment of PCa.

Loss of Igf2 Gene Imprinting in Murine Prostate Promotes Widespread Neoplastic Growth

Loss of imprinting (LOI) is an epigenetic event that relaxes an allele-specific restriction on gene expression. One gene that experiences LOI is the paracrine insulin-like growth factor IGF2, which occurs commonly in human prostate tissues during aging and tumorigenesis. However, the relationship between IGF2 LOI and prostate tumorigenesis has not been established functionally. In this study, we created a mouse model with CTCF-binding site mutations at the Igf2-H19 imprint control region that abolishes CTCF insulator activity, resulting in biallelic Igf2 expression that mimics increased levels seen with aging-induced LOI. We found that Igf2 LOI increased the prevalence and severity of prostatic intraepithelial neoplasia (PIN), a premalignant lesion. Engineering Nkx3.1 deficiency into our model increased the frequency of PIN lesions in an additive fashion. Prostates harboring LOI displayed increased MAPK signaling and epithelial proliferation. In human prostate tissue arrays, we documented a positive correlation in benign tissues of IGF2 levels with phospho-ERK and phospho-AKT levels. Overall, our results establish that Igf2 LOI is sufficient on its own to increase rates of neoplastic development in the prostate by upregulating critical cancer-associated signaling pathways. Cancer Res; 77(19); 5236-47. ©2017 AACR.

DNA methylation and histone modifications as epigenetic regulation in prostate cancer (Review)

Prostate cancer is the second most commonly diagnosed cancer in men in Poland after lung cancer and the third leading cause of cancer-related mortality after lung and colon cancer. The etiology of most cases of prostate cancer are not fully known, and therefore it is essential to search for the molecular basis of prostate cancer and markers for the early diagnosis of this type of cancer. Epigenetics deals with changes in gene expression that are not determined by changes in the DNA sequence. Epigenetic changes refer to changes in the structure of DNA, which are the result of DNA modification after replication and/or post-translational modification of proteins associated with DNA. In contrast to mutations, epigenetic changes are reversible and occur very rapidly. The major epigenetic mechanisms include DNA methylation, modification of histone proteins, chemical modification and chromatin remodeling changes in gene expression caused by microRNAs (miRNAs). Epigenetic changes play an important role in malignant transformation and can be specific to types of cancers including prostate cancer.

The stem cell factor (SCF)/c-KIT signalling in testis and prostate cancer

The stem cell factor (SCF) is a cytokine that specifically binds the tyrosine kinase receptor c-KIT. The SCF/c-KIT interaction leads to receptor dimerization, activation of kinase activity and initiation of several signal transduction pathways that control cell proliferation, apoptosis, differentiation and migration in several tissues. The activity of SCF/c-KIT system is linked with the phosphatidylinositol 3-kinase (PI3-K), the Src, the Janus kinase/signal transducers and activators of transcription (JAK/STAT), the phospholipase-C (PLC-γ) and the mitogen-activated protein kinase (MAPK) pathways. Moreover, it has been reported that cancer cases display an overactivation of c-KIT due to the presence of gain-of-function mutations or receptor overexpression, which renders c-KIT a tempting target for cancer treatment. In the case of male cancers the most documented activated pathways are the PI3-K and Src, both enhancing abnormal cell proliferation. It is also known that the Src activity in prostate cancer cases depends on the presence of tr-KIT, the cytoplasmic truncated variant of c-KIT that is specifically expressed in tumour tissues and, thus, a very interesting target for drug development. The present review provides an overview of the signalling pathways activated by SCF/c-KIT and discusses the potential application of c-KIT inhibitors for treatment of testicular and prostatic cancers.

Levels of plasma selenium and urinary total arsenic interact to affect the risk for prostate cancer

This study investigated whether plasma selenium levels modified the risk for prostate cancer (PC) related to arsenic exposure. We conducted a case-control study that included 318 PC patients and 318 age-matched, healthy control subjects. Urinary arsenic profiles were examined using HPLC-HG-AAS and plasma selenium levels were measured by ICP-MS. We found that plasma selenium levels displayed a significant dose-dependent inverse association with PC. The odds ratio (OR) and 95% confidence interval (CI) for PC was 0.07 (0.04-0.13) among participants with a plasma selenium level >28.06 μg/dL vs. ≤19.13 μg/dL. A multivariate analysis showed that participants with a urinary total arsenic concentration >29.28 μg/L had a significantly higher OR (1.75, 1.06-2.89) for PC than participants with ≤29.89 μg/L. The combined presence of a low plasma selenium level and a high urinary total arsenic concentration exponentially increased the OR for PC, and additively interacted with PSA at levels ≥20 ng/mL. This is the first epidemiological study to examine the combined effects of plasma selenium and urinary total arsenic levels on the OR for PC. Our data suggest a low plasma selenium level coupled with a high urinary total arsenic concentration creates a significant risk for aggressive PC.

HER2 gene amplification in patients with prostate cancer: Evaluating a CISH-based method

Prostate cancer (PCa) is one of the most widespread malignancies in the world. The role of the human epidermal growth factor receptor 2 (HER2) in the pathogenesis and progression of human PCa remains poorly understood. In contradiction with breast cancer, studies on HER2 overexpression and gene amplification in PCa have produced varying results, although the HER2 oncogene has been implicated in the biology of numerous tumor types, and serves as a prognostic marker and therapeutic target in breast cancer. Technical challenges are considered the main reasons for data discrepancies. Amplification of the HER2 gene has previously been reported in PCa, in which it was associated with tumor progression. The present study aimed to evaluate the prevalence and clinical significance of HER2 amplification in PCa. A total of 32 biopsy samples obtained from human prostate adenocarcinomas were evaluated by chromogenic in situ hybridization (CISH) to determine the frequency of patients with HER2 gene amplifications. High copy numbers of HER2 were detected in 19 of the prostate tumors analyzed. The results of the present study suggested that, in patients without amplification of HER2, high levels of prostate-specific antigen or a high Gleason score were not significantly correlated with a high pathologic stage. Furthermore, amplification levels of the HER2 gene were directly associated with pathologic stage in patients with PCa. Therefore, the potential use of HER2 as a prognostic factor or therapeutic target for PCa warrants further study.

Knockdown of GPR137,G Protein-coupled receptor 137, Inhibits the Proliferation and Migration of Human Prostate Cancer Cells

GPR137 belongs to the G protein-coupled receptor family involving the regulation of transmembrane signal transduction that launches pivotal cellular functions. However, its function in prostate cancer (PCa) has been rarely reported. It was found in this study that GPR137 was upregulated in PCa tissues as compared with that in paracancerous tissues. To see whether GPR137 could serve as a potential therapeutic target for PCa, GPR137 was knocked down to verify its biological function in PCa cells. Lentivirus-introduced short hairpin RNA (shRNA) was designed to silence GPR137 gene. It was found that silencing of GPR137 gene suppressed the proliferation and colony formation of PCa cell lines PC-3 and DU145. Further study indicated that growth inhibition by GPR137 knockdown was associated with cell cycle arrest at G0/G1 phase. Furthermore, silencing of GPR137 repressed the invasion and migration abilities of PC-3 cells via downregulating slug and snail and upregulating E-cadherin. Collectively, these findings imply that GPR137 plays an important role in the occurrence and progression of PCa and may prove to be a potential therapeutic target for the treatment of advanced PCa.

Methylation of Apoptosis-Associated Speck-Like Protein With a Caspase Recruitment Domain and Outcomes in Heart Failure

BACKGROUND

Heart failure (HF) is associated with inflammation characterized by the formation of the inflammasome, which triggers maturation of inflammatory cytokines. Apoptosis-associated speck-like protein with a caspase recruitment domain (ASC), a vital component of the inflammasome, is controlled through epigenetic modification, which may be a candidate pathway for worsening HF. This study examined the inflammasome pathway in HF and the relationships between ASC CpG methylation and outcomes in HF.

METHODS AND RESULTS

Stored samples from 155 HF outpatients (ejection fraction 29.9 ± 14.9%) were analyzed for percentage methylation of 7 CpG sites in the intron region preceding exon 1 of the ASC gene. ASC methylation was inversely related to ASC mRNA (r = -0.33; P < .001) and protein (r = -0.464; P < .001). ASC methylation had a positive linear relationship with ejection fraction (r = 0.85; P < .001), quality of life (r = 0.83; P < .001), and 6-minute walk test (r = 0.59; P = .023) and a negative linear relationship with depression (r = -0.81; P < .001) and anxiety (r = -0.75; P < .001). Higher ASC methylation was associated with a lower risk for clinical events (hazard ratio [HR] 0.16; P = .025), whereas higher protein (HR = 1.78; P = .045) and mRNA expression (HR = 1.18; P = .05) were associated with a greater risk.

CONCLUSIONS

Increased methylation of CpG sites in the intron region of ASC is associated with improved outcomes in HF. The associated decrease in ASC expression implicates this inflammatory mediator as a possible driver of HF outcomes and may represent a therapeutic target.

DNA methylation as a dynamic regulator of development and disease processes: spotlight on the prostate

Prostate development, benign hyperplasia and cancer involve androgen and growth factor signaling as well as stromal-epithelial interactions. We review how DNA methylation influences these and related processes in other organ systems such as how proliferation is restricted to specific cell populations during defined temporal windows, how androgens elicit their actions and how cells establish, maintain and remodel DNA methylation in a time and cell specific fashion. We also discuss mechanisms by which hormones and endocrine disrupting chemicals reprogram DNA methylation in the prostate and elsewhere and examine evidence for a reawakening of developmental epigenetic pathways as drivers of prostate cancer and benign prostate hyperplasia.

Frequent disruption of chromodomain helicase DNA-binding protein 8 (CHD8) and functionally associated chromatin regulators in prostate cancer

Abnormal expression and function of chromatin regulators results in the altered chromatin structure seen in cancer. The chromatin regulator CTCF, its cofactor CHD8, and antagonistic paralogue BORIS have wide-ranging effects on gene regulation. Their concurrent expression and regulation was examined in benign, localized, and metastatic prostate cancer (PCa) arrays with extended follow-up using an automated quantitative imaging system, VECTRA. Epithelial staining was quantified and compared against a range of clinicopathologic variables. CHD8 expression was decreased in HGPIN, localized, and metastatic PCa compared to benign (P < .001). CHD8 promoter hypermethylation, assessed by Quantitative Pyrosequencing, occurred in over 45% of primary cancers in this population as well as the TGCA database. Treatment of cell lines with the demethylating agent 5-Aza-2′-deoxycytidine reinduced expression. An interesting dichotomy for CHD8 was observed within primary cancers, with higher nuclear protein expression associated with adverse clinical outcomes including extracapsular extension (P = .007), presence of metastases (P = .025) and worse PSA-recurrence free survival (P = .048). CHD8 outperformed Gleason score and predicted biochemical failure within intermediate grade prostate cancers. The BORIS/CTCF expression ratio increased in localized (P = .03) and metastatic PCa (P = .006) and was associated with higher Gleason score (P = .02), increased tumor volume (P = .02) and positive margins (P = .04). Per cell heterogeneity of expression revealed all protein expression to be more heterogeneous in cancerous tissue (both P < .001), especially high grade (P < .01). In the first detailed analysis in cancer, a marked loss of CHD8 expression and increased BORIS/CTCF ratio indicate frequent disruption of CTCF and its effector genes in PCa.

Genomic Profiling Reveals Unique Molecular Alterations in Hepatoblastomas and Adjacent Hepatocellular Carcinomas in B6C3F1 Mice

The cell of origin of hepatoblastoma (HB) in humans and mice is unknown; it is hypothesized to be a transformed hepatocyte, oval cell, or hepatic progenitor cell. In mice, current dogma is that HBs arise from preexisting hepatocellular neoplasms as a result of further neoplastic transformation. However, there is little evidence supporting this direct relationship. To better understand the relationship between hepatocellular carcinoma (HCC) and HB and determine molecular similarities between mouse and human HB, global gene expression analysis and targeted mutation analysis were performed using HB, HCC, and adjacent liver from the same animals in a recent National Toxicology Program bioassay. There were significant differences in Hras and Ctnnb1 mutation spectra, and by microarray, HBs showed dysregulation of embryonic development, stem cell pluripotency, and genomic imprinting compared to HCC. Meta-analysis showed similarities between HB, early mouse embryonic liver, and hepatocyte-derived stem/progenitor cells compared to HCC. Our data show that there are striking differences between HB and HCC and suggest that HB is a significantly different entity that may arise from a hepatic precursor cell. Furthermore, mouse HB is similar to the human disease at the pathway level and therefore is likely a relevant model for evaluating human cancer hazard.

The epigenetics of prostate cancer diagnosis and prognosis: update on clinical applications

PURPOSE OF REVIEW

There is a major deficit in our ability to detect and predict the clinical behavior of prostate cancer (PCa). Epigenetic changes are associated with PCa development and progression. This review will focus on recent results in the clinical application of diagnostic and prognostic epigenetic markers.

RECENT FINDINGS

The development of high throughput technology has seen an enormous increase in the discovery of new markers that encompass epigenetic changes including those in DNA methylation and histone modifications. Application of these findings to urine and other biofluids, but also cancer and noncancerous prostate tissue, has resulted in new biomarkers. There has been a recent commercial development of a DNA methylation-based assay for identifying PCa risk from normal biopsy tissue. Other biomarkers are currently in the validation phase and encompass combinations of multiple genes.

SUMMARY

Epigenetic changes improve the specificity and sensitivity of PCa diagnosis and have the potential to help determine clinical prognosis. Additional studies will not only provide new and better biomarker candidates, but also have the potential to inform new therapeutic strategies given the reversibility of these processes.

Addressing the need for repeat prostate biopsy: new technology and approaches

No guidelines currently exist that address the need for rebiopsy in patients with a negative diagnosis of prostate cancer on initial biopsy sample analysis. Accurate diagnosis of prostate cancer in these patients is often complicated by continued elevation of serum PSA levels that are suggestive of prostate cancer, resulting in a distinct management challenge. Following negative initial findings of biopsy sample analysis, total serum PSA levels and serum PSA kinetics are ineffective indicators of a need for a repeat biopsy; therefore, patients suspected of having prostate cancer might undergo several unnecessary biopsy procedures. Several alternative strategies exist for identifying men who might be at risk of prostate cancer despite negative findings of biopsy sample analysis. Use of other serum PSA-related measurements enables more sensitive and specific diagnosis and can be combined with knowledge of clinicopathological features to improve outcomes. Other options include the FDA-approved Progensa(®) test and prostate imaging using MRI. Newer tissue-based assays that measure methylation changes in normal prostate tissue are currently being developed. A cost-effective strategy is proposed in order to address this challenging clinical scenario, and potential directions of future studies in this area are also described.

Evaluation of individual aging degree by standard-free, label-free LC-MS/MS quantification of formaldehyde-modified peptides

In this study, a standard-free, label-free LC-MS/MS method is proposed to evaluate aging based on the cross-linkage theory. First, an aging-biomarker screening model was set up in vitro with formaldehyde and the most abundant protein in plasma, human serum albumin (HSA), based on the Maillard reaction. The modification level of peptides cleaved from HSA was investigated using a liquid chromatography tandem mass spectrometry (LC-MS/MS) method with an (18)O-labeling technique. One formaldehyde-insensitive peptide and six formaldehyde-sensitive peptides that would be verified for being putative peptide-biomarkers were screened via the in vitro aging model. These six putative biomarkers were then preliminarily verified by plasma samples with the aldehyde-insensitive peptide serving as the internal standard. The verification results indicated that the peptides LDELRDEGK and VFDEFKPLVEEPQNLIK showed a significant quantitative difference among young/mid-aged/elderly groups of people.

Early treatment with metformin induces resistance against tumor growth in adult rats

It is known that antidiabetic drug metformin, which is used worldwide, has anti-cancer effects and can be used to prevent cancer growth. We tested the hypothesis that tumor cell growth can be inhibited by early treatment with metformin. For this purpose, adult rats chronically treated with metformin in adolescence or in adulthood were inoculated with Walker 256 carcinoma cells. Adult rats that were treated with metformin during adolescence presented inhibition of tumor growth, and animals that were treated during adult life did not demonstrate any changes in tumor growth. Although we do not have data to disclose a molecular mechanism to the preventive metformin effect, we present, for the first time, results showing that cancer growth in adult life is dependent on early life intervention, thus supporting a new therapeutic prevention for cancer.

Impact of a folic acid-enriched diet on urinary tract function in mice treated with testosterone and estradiol

Aging men are susceptible to developing lower urinary tract symptoms, but the underlying etiology is unknown and the influence of dietary and environmental factors on them is unclear. We tested whether a folic acid-enriched diet changed urinary tract physiology and biology in control male mice and male mice with urinary dysfunction induced by exogenous testosterone and estradiol (T+E2), which mimics changing hormone levels in aging humans. T+E2 treatment increased mouse urine output, time between voiding events, and bladder capacity and compliance. Consumption of a folic acid-enriched diet moderated these changes without decreasing prostate wet weight or threshold voiding pressure. One potential mechanism for these changes involves water balance. T+E2 treatment increases plasma concentrations of anti-diuretic hormone, which is offset at least in part by a folic acid-enriched diet. Another potential mechanism involves neural control of micturition. The folic acid-enriched diet, fed to T+E2-treated mice, increased voiding frequency in response to intravesicular capsaicin infusion and increased mRNA abundance of the capsaicin-sensitive cation channel transient receptor potential vanilloid subfamily member 1 (Trpv1) in L6 and S1 dorsal root ganglia (DRG) neurons. T+E2 treatment and a folic acid-enriched diet also modified DNA methylation, which is capable of altering gene expression. We found the enriched diet increased global DNA methylation in dorsal and ventral prostate and L6 and S1 DRG. Our results are consistent with folic acid acting to slow or reverse T+E2-mediated alteration in urinary function in part by normalizing water balance and enhancing or preserving afferent neuronal function.

Berberine inhibits the proliferation of prostate cancer cells and induces G₀/G₁ or G₂/M phase arrest at different concentrations

Prostate cancer is the second most common disease of the male reproductive system. Berberine is a quaternary ammonium salt that is extracted from plants. The aim of the current study was to explore the antitumor activity of berberine in prostate cancer cells and identify the underlying mechanism of its effects. PC3 human and RM‑1 mouse prostate cancer cells were treated with increasing concentrations of berberine, followed by analysis of the cell viability with an MTT assay. The results demonstrated that berberine markedly inhibited the proliferation of PC3 and RM‑1 cells, and that the inhibitory effects to PC3 and RM‑1 were enhanced in a concentration‑ and time‑dependent manner. Flow cytometry was used to analyze the cell cycle of PC3 human prostate cancer cells, and the results demonstrated that G0/G1 phase arrest was induced following treatment with 10 µM berberine (P<0.05). However, with an increased concentration of berberine (50 µM) the survival rate of PC3 cells at the G2/M phase was significantly increased compared with the cells treated with 10 µM berberine, which suggests that different cell cycle signaling pathways were activated when PC3 cells were treated with low and high concentrations of berberine. Thus, clarifying the mechanism underlying these effects in prostate cancer may provide novel molecular targets for prostate cancer therapy.

Association between RUNX3 promoter methylation and non-small cell lung cancer: a meta-analysis

BACKGROUND

Runt-related transcription factor 3 (RUNX3) is a known regulator in the transforming growth factor (TGF)-β signaling pathway, which promoter methylation playing a crucial role in diverse neoplasias. However, the relationship between RUNX3 promoter methylation and non-small cell lung cancer (NSCLC) remains to be clarified.

METHODS

We searched Pubmed, Embase, Cochrane Central, and Chinese Biological Medicine database, for articles published in English or Chinese until March 7, 2014. Our main analyses were focused on the association between RUNX3 promoter methylation and risk of NSCLC by meta-analysis methods. If heterogeneity was observed, we used random effects model to calculate the overall odds ratios, otherwise fixed effects model was used. Subgroup analyses and meta-regression analyses were employed to detect the sources of the heterogeneity. Sensitivity analysis was performed to evaluate the stability of our studies. A funnel plot and Egger's test were conducted to investigate any potential publication bias.

RESULTS

A total of 1,368 samples from 13 literatures were involved in this meta-analysis. The pooled odds ratio (OR) of RUNX3 methylation in NSCLC specimens compared to non-cancer controls was 6.70 [95% confidence interval (CI): 4.64-9.67]. In the analysis of specimen-types subgroup, the summary OR was 5.79 (95% CI: 3.97-8.46) for tissue specimen subgroup, and that was 45.64 (95% CI: 5.89-353.72) for serum specimen subgroup. The ORs for the age ≤60 years, 60-65 years and >65 years subgroup were 5.19 (95% CI: 3.27-8.24), 9.45 (95% CI: 2.45-36.45) and 13.23 (95% CI: 5.59-31.28) respectively. The result of meta-regression indicated that age was fundamental source of heterogeneity (coefficient =0.61, P=0.046, adjusted R(2) =100%). No publication bias was detected. In cancer specimens, the RUNX3 methylation was associated with histological type of the NSCLC, but no significant differences were found for RUNX3 methylation in relation to gender, smoking history, tumor TNM stage or tumor differentiation level.

CONCLUSIONS

This meta-analysis of pooled data provides additional evidence to support a strong association between methylation of the RUNX3 promoter and NSCLC. RUNX3 methylation was increasing with age.

Polyomavirus BK and prostate cancer: an unworthy scientific effort?

The Polyomavirus BK (BKV) has been proposed to be one of the possible co-factors in the genesis of prostate cancer (PCa) but, so far, the only convincing suggestion is the hypothesis of a “hit and run” carcinogenic mechanism induced by the virus at early stages of this disease. To support this hypothesis we conducted an updated systematic review on previous studies regarding the association between BKV and PCa, in order to interpret the contrasting results and to explore whether there might be a significant virus-disease link. This updated analysis provides evidence for a significant link between BKV expression and PCa development, particularly between the BKV infection and the cancer risk. Forthcoming scientific efforts that take cue from this study might overcome the atavistic and fruitless debate regarding the BKV-PCa association.

Clinical validation of an epigenetic assay to predict negative histopathological results in repeat prostate biopsies

PURPOSE

The DOCUMENT multicenter trial in the United States validated the performance of an epigenetic test as an independent predictor of prostate cancer risk to guide decision making for repeat biopsy. Confirming an increased negative predictive value could help avoid unnecessary repeat biopsies.

MATERIALS AND METHODS

We evaluated the archived, cancer negative prostate biopsy core tissue samples of 350 subjects from a total of 5 urological centers in the United States. All subjects underwent repeat biopsy within 24 months with a negative (controls) or positive (cases) histopathological result. Centralized blinded pathology evaluation of the 2 biopsy series was performed in all available subjects from each site. Biopsies were epigenetically profiled for GSTP1, APC and RASSF1 relative to the ACTB reference gene using quantitative methylation specific polymerase chain reaction. Predetermined analytical marker cutoffs were used to determine assay performance. Multivariate logistic regression was used to evaluate all risk factors.

RESULTS

The epigenetic assay resulted in a negative predictive value of 88% (95% CI 85-91). In multivariate models correcting for age, prostate specific antigen, digital rectal examination, first biopsy histopathological characteristics and race the test proved to be the most significant independent predictor of patient outcome (OR 2.69, 95% CI 1.60-4.51).

CONCLUSIONS

The DOCUMENT study validated that the epigenetic assay was a significant, independent predictor of prostate cancer detection in a repeat biopsy collected an average of 13 months after an initial negative result. Due to its 88% negative predictive value adding this epigenetic assay to other known risk factors may help decrease unnecessary repeat prostate biopsies.