DNA methylation in promoter region as biomarkers in prostate cancer

"Whole genome bisulfite sequencing of serum extracellular vesicle DNA identifies alterations in mitochondrial DNA methylation in early onset preeclampsia"

Early-onset preeclampsia (EOPE) is a serious pregnancy complication. Understanding its underlying mechanisms could lead to improved diagnosis and management. Genome-wide DNA methylation changes in circulating Extracellular Vesicle DNA (EV-DNA) from women with EOPE could serve as a non-invasive approach to identify key regions and genes that could serve as biomarkers to understand placental pathophysiology. In this case-control study, serum extracellular vesicles were isolated from 3rd trimester pregnant women and characterized using Nanoparticle Tracking Analysis and Transmission Electron Microscopy. The circulating EV-DNA samples were subjected to Whole Genome Bisulfite Sequencing analysis (WGBS) to identify differentially methylated CpGs (DMCs) sites in EOPE cases compared to control. A total of 154 DMCs were identified in EV-DNA, of which 131 were hypomethylated and 23 were hypermethylated. Majority of DMCs were of mitochondrial origin. Previously, it has been reported that oxidative stress, decreased trophoblast differentiation, and invasion are linked to preeclampsia pathogenesis and are related to mitochondrial dysfunction. Therefore, DMCs of the mitochondrial genes like MT-ND1, MT-ND4, MT-CO2, MT-CO3, and MT-RNR1 were selected for validation and showed a similar trend by pyrosequencing. The expression of these genes were also altered in circulating extracellular vesicles. Our study shows changes in the DNA methylation patterns of circulating EV-DNA in women with EOPE. These changes, especially in mitochondrial genes, could lead to mitochondrial dysfunction and contribute EOPE pathogenesis. These findings suggest that these alterations could be explored as non-invasive approach to better understand placental health and improve disease management.

Decoding PTEN regulation in clear cell renal cell carcinoma: Pathway for biomarker discovery and therapeutic insights

Renal cell carcinoma is the most common adult renal solid tumor and the deadliest urological cancer, with clear cell renal cell carcinoma (ccRCC) being the predominant subtype. The PI3K/AKT signaling pathway assumes a central role in ccRCC tumorigenesis, wherein its abnormal activation confers a highly aggressive phenotype, leading to swift resistance against current therapies and distant metastasis. Thus, treatment resistance and disease progression remain a persistent clinical challenge in managing ccRCC effectively. PTEN, an antagonist of the PI3K/AKT signaling axis, emerges as a crucial factor in tumor progression, often experiencing loss or inactivation in ccRCC, thereby contributing to elevated mortality rates in patients. Therefore, understanding the molecular mechanisms underlying PTEN suppression in ccRCC tumors holds promise for the discovery of biomarkers and therapeutic targets, ultimately enhancing patient monitoring and treatment outcomes. The present review aims to summarize these mechanisms, emphasizing their potential prognostic, predictive, and therapeutic value in managing ccRCC.

Epigenome-wide association study of prostate cancer in African American men identified differentially methylated genes

INTRODUCTION

Men with African ancestry have the highest incidence and mortality rates of prostate cancer (PCa) worldwide.

METHODS

This study aimed to identify differentially methylated genes between tumor vs. adjacent normal and aggressive vs. indolent PCa in 121 African American patients. Epigenome-wide DNA methylation patterns in tumor DNA were assessed using the human Illumina Methylation EPIC V1 array.

RESULTS

Around 5,139 differentially methylated CpG-sites (q < 0.01, lΔβl > 0.2) were identified when comparing normal vs. tumor, with an overall trend of hypermethylation in prostate tumors.  Multiple representative differentially methylated regions (DMRs), including immune-related genes, such as CD40, Galectin3, OX40L, and STING, were detected in prostate tumors when compared to adjacent normal tissues. Based on an epigenetic clock model, we observed that tumors' total number of stem cell divisions and the stem cell division rate were significantly higher than adjacent normal tissues. Regarding PCa aggressiveness, 2,061 differentially methylated CpG-sites (q < 0.05, lΔβl > .05) were identified when the grade group (GG)1 was compared with GG4/5. Among these 2,061 CpG sites, 155 probes were consistently significant in more than one comparison. Among these genes, several immune system genes, such as COL18A1, S100A2, ITGA4, HLA-C, and ADCYAP1, have previously been linked to tumor progression in PCa.

CONCLUSION

Several differentially methylated genes involved in immune-oncologic pathways associated with disease risk or aggressiveness were identified. In addition, 261 African American-specific differentially methylated genes related to the risk of PCa were identified. These results can shedlight on potential mechanisms contributing to PCa disparities in the African American Population.

Epigenetic age acceleration is associated with blood lipid levels in a multi-ancestry sample of older U.S. adults

BACKGROUND

Dyslipidemia, which is characterized by an unfavorable lipid profile, is a key risk factor for cardiovascular disease (CVD). Understanding the relationships between epigenetic aging and lipid levels may help guide early prevention and treatment efforts for dyslipidemia.

METHODS

We used weighted linear regression to cross-sectionally investigate the associations between five measures of epigenetic age acceleration estimated from whole blood DNA methylation (HorvathAge Acceleration, HannumAge Acceleration, PhenoAge Acceleration, GrimAge Acceleration, and DunedinPACE) and four blood lipid measures (total cholesterol (TC), LDL-C, HDL-C, and triglycerides (TG)) in 3,813 participants (mean age = 70 years) from the Health and Retirement Study (HRS). As a sensitivity analysis, we examined the same associations in participants who fasted prior to the blood draw (n = 2,531) and in participants who did not take lipid-lowering medication (n = 1,869). Using interaction models, we also examined whether demographic factors including age, sex, and educational attainment modified the relationships between epigenetic age acceleration and blood lipids.

RESULTS

After adjusting for age, race/ethnicity, sex, fasting status, and lipid-lowering medication use, greater epigenetic age acceleration was associated with lower TC, HDL-C, and LDL-C, and higher TG (p < 0.05), although the effect sizes were relatively small (e.g., < 7 mg/dL of TC per standard deviation in epigenetic age acceleration). GrimAge acceleration and DunedinPACE associations with all lipids remained significant after further adjustment for body mass index, smoking status, and educational attainment. These associations were stronger in participants who fasted and who did not use lipid-lowering medication, particularly for LDL-C. We observed the largest number of interactions between DunedinPACE and demographic factors, where the associations with lipids were stronger in younger participants, females, and those with higher educational attainment.

CONCLUSION

Multiple measures of epigenetic age acceleration are associated with blood lipid levels in older adults. A greater understanding of how these associations differ across demographic groups can help shed light on the relationships between aging and downstream cardiovascular diseases. The inverse associations between epigenetic age and TC and LDL-C could be due to sample limitations or non-linear relationships between age and these lipids, as both TC and LDL-C decrease faster at older ages.

Signaling, cancer cell plasticity, and intratumor heterogeneity

Cancer's complexity is in part due to the presence of intratumor heterogeneity and the dynamic nature of cancer cell plasticity, which create substantial obstacles in effective cancer management. Variability within a tumor arises from the existence of diverse populations of cancer cells, impacting the progression, spread, and resistance to treatments. At the core of this variability is the concept of cellular plasticity - the intrinsic ability of cancer cells to alter their molecular and cellular identity in reaction to environmental and genetic changes. This adaptability is a cornerstone of cancer's persistence and progression, making it a formidable target for treatments. Emerging studies have emphasized the critical role of such plasticity in fostering tumor diversity, which in turn influences the course of the disease and the effectiveness of therapeutic strategies. The transformative nature of cancer involves a network of signal transduction pathways, notably those that drive the epithelial-to-mesenchymal transition and metabolic remodeling, shaping the evolutionary path of cancer cells. Despite advancements, our understanding of the precise molecular machinations and signaling networks driving these changes is still evolving, underscoring the necessity for further research. This editorial presents a series entitled "Signaling Cancer Cell Plasticity and Intratumor Heterogeneity" in Cell Communication and Signaling, dedicated to unraveling these complex processes and proposing new avenues for therapeutic intervention.

Methylation signatures as biomarkers for non-invasive early detection of breast cancer: A systematic review of the literature

BACKGROUND

Early detection of breast cancer would help alleviate the burden of treatment for early-stage breast cancer and help patient prognosis. There is currently no established gene panel that utilizes the potential of DNA methylation as a molecular signature for the early detection of breast cancer. This systematic review aims to identify the optimal methylation biomarkers for a non-invasive liquid biopsy assay and the gaps in knowledge regarding biomarkers for early detection of breast cancer.

METHODS

Following the PRISMA-ScR method, Pubmed and Google Scholar was searched for publications related to methylation biomarkers in breast cancer over a five-year period. Eligible publications were mined for key data fields such as study aims, cohort demographics, types of breast cancer studied, technologies used, and outcomes. Data was analyzed to address the objectives of the review.

RESULTS

Literature search identified 112 studies of which based on eligibility criteria, 13 studies were included. 28 potential methylation gene targets were identified, of which 23 were methylated at the promoter region, 1 was methylated in the body of the gene and 4 were methylated at yet to be identified locations.

CONCLUSIONS

Our evaluation shows that at minimum APC, RASSFI, and FOXA1 genes would be a promising set of genes to start with for the early detection of breast cancer, based on the sensitivity and specificity outlined in the studies. Prospective studies are needed to optimize biomarkers for broader impact in early detection of breast cancer.

The Influence of Smoking and Occupational Risk Factors on DNA Methylation in the AHRR and F2RL3 Genes

BACKGROUND

AHRR and F2RL3 hypomethylation has been associated with lung cancer. In this study, we investigated the cross-sectional association between smoking and occupational exposures, and AHRR and F2RL3 methylation.

METHODS

A case-control study was nested in CARTaGENE to examine the association between AHRR and F2RL3 methylation and lung cancer risk (200 cases; 400 controls). A secondary analysis was conducted using the data collected from this nested study; namely, baseline information on participants' smoking behavior and longest-held job was obtained. A cumulative smoking index summarized information on the number of cigarettes smoked, duration of smoking, and time since cessation. Exposure to 13 occupational agents was estimated using the Canadian Job Exposure Matrix. In baseline blood samples, methylation ratios of 40 CpG sites in the AHRR and F2RL3 genes were measured using Sequenom EpiTYPER. Separate least squares regression models were used to estimate the associations between smoking and occupational exposures, and average AHRR and F2RL3 methylation levels, while adjusting for confounders identified from directed acyclic graphs.

RESULTS

In both genes, smoking was associated with lower average methylation levels. Occupational exposure to aromatic amines, cadmium, and formaldehyde were associated with lower AHRR methylation while, only benzene was associated with F2RL3 hypomethylation; these associations were stronger among ever smokers.

CONCLUSIONS

Our findings support that smoking and occupational exposures to some agents are associated with AHRR and F2RL3 hypomethylation.

IMPACT

Our results inform on mechanisms underlying environmental exposures in lung cancer etiology; future studies should prioritize studying joint exposures.

Effects of blood mercury accumulation on DNA methylation levels in the Khorat snail-eating turtle (Malayemys khoratensis)

Mercury (Hg) has adverse effects on humans and wildlife. Hg exposure can cause significant alterations in DNA methylation, an epigenetic modification that causes various illnesses. Hg accumulation in the blood of the Khorat snail-eating turtle (Malayemys khoratensis) from northeastern Thailand was previously reported. Thus, this study aimed to assess total mercury (THg) levels in M. khoratensis blood and to examine the impact of these concentrations on DNA methylation (5-methylcytosine, 5-mC) levels. We divided turtles based on morphological characteristics into two groups, normal and deformed, and then the levels of each variable in both groups were assessed. The deformed group presented higher mean THg concentration and DNA methylation levels compared to the normal group; however, the differences were not significant. Additionally, we found no correlation between DNA methylation levels and THg concentrations in both groups. This study is the first attempt to investigate the relationship between mercury accumulation and DNA methylation in the blood of deformed freshwater turtles.

Unveiling the ESR1 Conformational Stability and Screening Potent Inhibitors for Breast Cancer Treatment

BACKGROUND

The current study recognizes the significance of estrogen receptor alpha (ERα) as a member of the nuclear receptor protein family, which holds a central role in the pathophysiology of breast cancer. ERα serves as a valuable prognostic marker, with its established relevance in predicting disease outcomes and treatment responses.

METHODS

In this study, computational methods are utilized to search for suitable drug-like compounds that demonstrate analogous ligand binding kinetics to ERα.

RESULTS

Docking-based simulation screened out the top 5 compounds - ZINC13377936, NCI35753, ZINC35465238, ZINC14726791, and NCI663569 against the targeted protein. Further, their dynamics studies reveal that the compounds ZINC13377936 and NCI35753 exhibit the highest binding stability and affinity.

CONCLUSION

Anticipating the competitive inhibition of ERα protein expression in breast cancer, we envision that both ZINC13377936 and NCI35753 compounds hold substantial promise as potential therapeutic agents. These candidates warrant thorough consideration for rigorous In vitro and In vivo evaluations within the context of clinical trials. The findings from this current investigation carry significant implications for the advancement of future diagnostic and therapeutic approaches for breast cancer.

Structure-based virtual screening, molecular simulation and free energy calculations of traditional Chinese medicine, ZINC database revealed potent inhibitors of estrogen-receptor α (ERα)

Breast Cancer, a heterogeneous disease at the molecular level, is the most common cause of woman mortality worldwide. We used molecular screening and simulation approaches to target nuclear receptor protein-estrogen receptor alpha (Erα) protein to design and develop of specific and compelling drugs from traditional Chinese medicine (TCM), and ZINC database against pathophysiology of breast cancer. Using virtual screening, only six hits TCM22717, TCM23524, TCM31953, while ZINC05632920, ZINC05773243, and ZINC12780336 demonstrated better pharmacological potential than the 4-hydroxytamoxifen (OHT) taken as control. Binding mode of each of the top hit revealed that these compounds could block the main active site residues and block the function of Erα protein. Moreover, molecular simulation revealed that the identified compounds exhibit stable dynamics and may induce stronger therapeutic effects in experimental setup. All the complexes reported tighter structural packing and less flexible behaviour. We found that the average hydrogen bonds in the identified complexes remained higher than the control drug. Finally, the total binding free energy demonstrated the best hits among the all. The BF energy results revealed -30.4525 ± 3.3565 for the 4-hydroxytamoxifen (OHT)/Erα complex, for the TCM22717/Erα -57.0597 ± 3.4852 kcal/mol, for the TCM23524/Erα complex the BF energy was -56.9084 ± 3.3737 kcal/mol, for the TCM31953/Erα the BF energy was -32.4191 ± 3.8864 kcal/mol while for the ZINC05632920/Erα complex -46.3182 ± 2.7380, ZINC05773243/Erα complex -38.3690 ± 2.8240, and ZINC12780336/Erα complex the BF energy was calculated to be -35.8048 ± 4.1571 kcal/mol.Communicated by Ramaswamy H. Sarma.

High dietary folate and low vitamin B12 in the parental diet disturbed the epigenetics of imprinted genes MEST and PHLDA2 in mice placenta

To elucidate the dietary effects of vitamin B12 and folic acid on fetal and placental epigenetics, different dietary combinations of folic acid and low vitamin B12 (four groups) were fed to the animals (C57BL/6 mice), and mating was carried out within each group in the F0 generation. After weaning for 3 weeks in the F1 generation one group of mice was continued on the same diet (sustained group) while the other was shifted to a normal diet (transient group) for 6-8 weeks (F1). Mating was carried out again within each group, and on day 20 of gestation, the maternal placenta (F1) and fetal tissues (F2) were isolated. Expression of imprinted genes and various epigenetic mechanisms, including global and gene-specific DNA methylation and post-translational histone modifications, were studied. Evaluation of mRNA levels of MEST and PHLDA2 in placental tissue revealed that their expression is maximally influenced by vitamin B12 deficiency and high folate conditions. The gene expression of MEST and PHLDA2 was found significantly decreased in the F0 generation, with the over-expression of the genes in BDFO dietary groups. These dietary combinations also resulted in DNA methylation changes in both generations, which may not play a role in gene expression regulation. However, altered histone modifications were found to be the major regulatory factor in controlling the expression of genes in the F1 generation. The imbalance of low vitamin B12 and high folate leads to increased levels of activating histone marks, contributing to increased gene expression.

Consistent DNA Hypomethylations in Prostate Cancer

With approximately 1.4 million men annually diagnosed with prostate cancer (PCa) worldwide, PCa remains a dreaded threat to life and source of devastating morbidity. In recent decades, a significant decrease in age-specific PCa mortality has been achieved by increasing prostate-specific antigen (PSA) screening and improving treatments. Nevertheless, upcoming, augmented recommendations against PSA screening underline an escalating disproportion between the benefit and harm of current diagnosis/prognosis and application of radical treatment standards. Undoubtedly, new potent diagnostic and prognostic tools are urgently needed to alleviate this tensed situation. They should allow a more reliable early assessment of the upcoming threat, in order to enable applying timely adjusted and personalized therapy and monitoring. Here, we present a basic study on an epigenetic screening approach by Methylated DNA Immunoprecipitation (MeDIP). We identified genes associated with hypomethylated CpG islands in three PCa sample cohorts. By adjusting our computational biology analyses to focus on single CpG-enriched 60-nucleotide-long DNA probes, we revealed numerous consistently differential methylated DNA segments in PCa. They were associated among other genes with NOTCH3, CDK2AP1, KLK4, and ADAM15. These can be used for early discrimination, and might contribute to a new epigenetic tumor classification system of PCa. Our analysis shows that we can dissect short, differential methylated CpG-rich DNA fragments and combinations of them that are consistently present in all tumors. We name them tumor cell-specific differential methylated CpG dinucleotide signatures (TUMS).

ACBD3 Bioinformatic Analysis and Protein Expression in Breast Cancer Cells

ACBD3 overexpression has previously been found to correlate with worse prognosis for breast cancer patients and, as an incredibly diverse protein in both function and cellular localisation, ACBD3 may have a larger role in breast cancer than previously thought. This study further investigated ACBD3′s role in breast cancer. Bioinformatic databases were queried to characterise ACBD3 expression and mutation in breast cancer and to investigate how overexpression affects breast cancer patient outcomes. Immunohistochemistry was carried out to examine ACBD3 location within cells and tissue structures. ACBD3 was more highly expressed in breast cancer than in any other cancer or matched normal tissue, and expression over the median level resulted in reduced relapse-free, overall, and distant metastasis-free survival for breast cancer patients as a whole, with some differences observed between subtypes. IHC analysis found that ACBD3 levels varied based on hormone receptor status, indicating that ACBD3 could be a candidate biomarker for poor patient prognosis in breast cancer and may possibly be a biomarker for ER signal reprogramming of precancerous breast tissue.

SEEMLIS: a flexible semi-automated method for enrichment of methylated DNA from low-input samples

Background

DNA methylation alterations have emerged as hallmarks of cancer and have been proposed as screening, prognostic, and predictive biomarkers. Traditional approaches for methylation analysis have relied on bisulfite conversion of DNA, which can damage DNA and is not suitable for targeted gene analysis in low-input samples. Here, we have adapted methyl-CpG-binding domain protein 2 (MBD2)-based DNA enrichment for use on a semi-automated exclusion-based sample preparation (ESP) platform for robust and scalable enrichment of methylated DNA from low-input samples, called SEEMLIS.

Results

We show that combining methylation-sensitive enzyme digestion with ESP-based MBD2 enrichment allows for single gene analysis with high sensitivity for GSTP1 in highly impure, heterogenous samples. We also show that ESP-based MBD2 enrichment coupled with targeted pre-amplification allows for analysis of multiple genes with sensitivities approaching the single cell level in pure samples for GSTP1 and RASSF1 and sensitivity down to 14 cells for these genes in highly impure samples. Finally, we demonstrate the potential clinical utility of SEEMLIS by successful detection of methylated gene signatures in circulating tumor cells (CTCs) from patients with prostate cancer with varying CTC number and sample purity.

Conclusions

SEEMLIS is a robust assay for targeted DNA methylation analysis in low-input samples, with flexibility at multiple steps. We demonstrate the feasibility of this assay to analyze DNA methylation in prostate cancer cells using CTCs from patients with prostate cancer as a real-world example of a low-input analyte of clinical importance. In summary, this novel assay provides a platform for determining methylation signatures in rare cell populations with broad implications for research as well as clinical applications.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13148-022-01252-4.

Dysregulation of DNA Methylation and Epigenetic Clocks in Prostate Cancer among Puerto Rican Men

In 2021, approximately 248,530 new prostate cancer (PCa) cases are estimated in the United States. Hispanic/Latinos (H/L) are the second largest racial/ethnic group in the US. The objective of this study was to assess DNA methylation patterns between aggressive and indolent PCa along with ancestry proportions in 49 H/L men from Puerto Rico (PR). Prostate tumors were classified as aggressive (n = 17) and indolent (n = 32) based on the Gleason score. Genomic DNA samples were extracted by macro-dissection. DNA methylation patterns were assessed using the Illumina EPIC DNA methylation platform. We used ADMIXTURE to estimate global ancestry proportions. We identified 892 differentially methylated genes in prostate tumor tissues as compared with normal tissues. Based on an epigenetic clock model, we observed that the total number of stem cell divisions (TNSC) and stem cell division rate (SCDR) were significantly higher in tumor than adjacent normal tissues. Regarding PCa aggressiveness, 141 differentially methylated genes were identified. Ancestry proportions of PR men were estimated as African, European, and Indigenous American; these were 24.1%, 64.2%, and 11.7%, respectively. The identification of DNA methylation profiles associated with risk and aggressiveness of PCa in PR H/L men will shed light on potential mechanisms contributing to PCa disparities in PR population.

Epigenetic approaches for cervical neoplasia screening (Review)

Human papillomavirus (HPV) infection is the leading cause of cervical cancer. The Papanicolaou cytology test is the usually employed type of screening for this infection; however, its sensibility is limited. Only a small percentage of women infected with high-risk HPV develop cervical cancer with an array of genetic and epigenetic modifications. Thus, it is necessary to develop rapid, reproducible and minimally invasive technologies for screening. DNA methylation has gained attention as an alternative method for molecular diagnosis and prognosis in HPV infection. The aim of the present review was to highlight the potential of DNA methylation in cervical neoplasia screening for clinical applications. It was observed that the methylation human and viral genes was correlated with high-grade lesions and cancer. Methylation biomarkers have shown a good capacity to discriminate between high-grade lesions with a transformative potential and cervical cancer, being able to detect these modifications at an early stage. With further research, the epigenetic profiles and subtypes of the tumors could be elaborated, which would aid in therapy selection by opening avenues in personalized precision medicine. Response to therapy could also be evaluated through such methods and the accessibility of liquid biopsies would allow a constant monitoring of the patient's status without invasive sampling techniques.

Epigenetically inactivated RASSF1A as a tumor biomarker

RASSF1A, one of the eight isoforms of the RASSF1 gene, is a tumor suppressor gene that influences tumor initiation and development. In cancer, RASSF1A is frequently inactivated by mutations, loss of heterozygosity, and, most commonly, by promoter hypermethylation. Epigenetic inactivation of RASSF1A was detected in various cancer types and led to significant interest; current research on RASSF1A promoter methylation focuses on its roles as an epigenetic tumor biomarker. Typically, researchers analyzed genomic DNA (gDNA) to measure the amount of RASSF1A promoter methylation. Cell-free DNA (cfDNA) from liquid biopsies is a recent development showing promise as an early cancer diagnostic tool using biomarkers, such as RASSF1A. This review discusses the evidence on aberrantly methylated RASSF1A in gDNA and cfDNA from different cancer types and its utility for early cancer diagnosis, prognosis, and surveillance. We compared methylation frequencies of RASSF1A in gDNA and cfDNA in various cancer types. The weaknesses and strengths of these analyses are discussed. In conclusion, although the importance of RASSSF1A methylation to cancer has been established and is included in several diagnostic panels, its diagnostic utility is still experimental.

Five-gene signature associating with Gleason score serve as novel biomarkers for identifying early recurring events and contributing to early diagnosis for Prostate Adenocarcinoma

Background: Compared to non-recurrent type, recurrent prostate adenocarcinoma (PCa) is highly fatal, and significantly shortens the survival time of affected patients. Early and accurate laboratory diagnosis is particularly important in identifying patients at high risk of recurrence, necessary for additional systemic intervention. We aimed to develop efficient and accurate diagnostic and prognostic biomarkers for new PCa following radical therapy. Methods: We identified differentially expressed genes (DEGs) and clinicopathological data of PCa patients from Gene Expression Omnibus (GEO) datasets and The Cancer Genome Atlas (TCGA) repositories. We then uncovered the most relevant clinical traits and genes modules associated with PCa prognosis using the Weighted gene correlation network analysis (WGCNA). Univariate Cox regression analysis and multivariate Cox proportional hazards (Cox-PH) models were performed to identify candidate gene signatures related to Disease-Free Interval (DFI). Data for internal and external cohorts were utilized to test and validate the accuracy and clinical utility of the prognostic models. Results: We constructed and validated an accurate and reliable model for predicting the prognosis of PCa using 5 Gleason score-associated gene signatures (ZNF695, CENPA, TROAP, BIRC5 and KIF20A). The ROC and Kaplan-Meier analysis revealed the model was highly accurate in diagnosing and predicting the recurrence and metastases of PCa. The accuracy of the model was validated using the calibration curves based on internal TCGA cohort and external GEO cohort. Using the model, patients could be prognostically stratified in to various groups including TNM classification and Gleason score. Multivariate analysis revealed the model could independently predict the prognosis of PCa patients and its utility was superior to that of clinicopathological characteristics. In addition, we fund the expression of the 5 gene signatures strongly and positively correlated with tumor purity but negatively correlated with infiltration CD8+ T cells to the tumor microenvironment. Conclusions: A 5 gene signatures can accurately be used in the diagnosis and prediction of PCa prognosis. Thus this can guide the treatment and management prostate adenocarcinoma.

Targeted DNA methylation profiling reveals epigenetic signatures in peanut allergy

DNA methylation (DNAm) has been shown to play a role in mediating food allergy; however, the mechanism by which it does so is poorly understood. In this study, we used targeted next-generation bisulfite sequencing to evaluate DNAm levels in 125 targeted highly informative genomic regions containing 602 CpG sites on 70 immune-related genes to understand whether DNAm can differentiate peanut allergy (PA) versus nonallergy (NA). We found PA-associated DNAm signatures associated with 12 genes (7 potentially novel to food allergy, 3 associated with Th1/Th2, and 2 associated with innate immunity), as well as DNAm signature combinations with superior diagnostic potential compared with serum peanut–specific IgE for PA versus NA. Furthermore, we found that, following peanut protein stimulation, peripheral blood mononuclear cell (PBMCs) from PA participants showed increased production of cognate cytokines compared with NA participants. The varying responses between PA and NA participants may be associated with the interaction between the modification of DNAm and the interference of environment. Using Euclidean distance analysis, we found that the distances of methylation profile comprising 12 DNAm signatures between PA and NA pairs in monozygotic (MZ) twins were smaller than those in randomly paired genetically unrelated individuals, suggesting that PA-related DNAm signatures may be associated with genetic factors.

Glutathione S transferase T1 gene polymorphism and its promoter methylation are associated with breast cancer susceptibility in Egyptian women

BACKGROUND

Breast cancer (BC) is one of the leading causes of cancer mortality in women. Glutathione S-transferase (GSTT1) is involved in activation of detoxification reactions and catalysis of chemicals conjugation with glutathione. GSTT1 genotype is a limiting factor for some environmental diseases. Epigenetic changes have an essential role in BC through inappropriate interaction between genomic and environmental risk factors.

AIM

This study was directed to explore the association of BC risk with GSTT1 genetic variations and its methylation status in Egyptian women.

DESIGN AND METHODS

This study included 100 healthy women as the control group and 100 patients were clinically and histologically diagnosed with breast cancer. All blood samples were used for genomic DNA extraction. GSTT1 genotyping was accomplished by multiplex PCR and methylation-specific PCR was used to analyze the GSTT1 promoter methylation status.

RESULTS

Breast cancer patients showed significant incidence of null GSTT1 in relation to controls (p = 0.004). GSTT1 gene promoter methylation status showed significant difference between hypermethylated and unmethylated patients when compared with healthy subjects (p = 0.005). GSTT1 promoter methylation status was not significantly associated with null genotype. There was no significant association between GSTT1-null genotypes and BC stage in cases with or without family history, but for promotor methylation, there was significant association with stage III and IV breast cancer disease.

CONCLUSION

GSTT1 null genetic variant and promoter hypermethylation in the GSTT region of the gene may be considered as critical risk factors for BC in Egyptian women.

Precision Medicine Approach in Prostate Cancer

Prostate cancer is the most prevalent type of cancer and the second cause of death in men worldwide. Various diagnostic and treatment procedures are available for this type of malignancy, but High-grade or locally advanced prostate cancers showed the potential to develop to lethal phase that can be causing dead. Therefore, new approaches are needed to prolong patients' survival and to improve their quality of life. Precision medicine is a novel emerging field that plays an essential role in identifying new sub-classifications of diseases and in providing guidance in treatment that is based on individual multi-omics data. Multi-omics approaches include the use of genomics, transcriptomics, proteomics, metabolomics, epigenomics and phenomics data to unravel the complexity of a disease-associated biological network, to predict prognostic biomarkers, and to identify new targeted drugs for individual cancer patients. We review the impact of multi-omics data in the framework of systems biology in the era of precision medicine, emphasising the combination of molecular imaging modalities with highthroughput techniques and the new treatments that target metabolic pathways involved in prostate cancer.

Differential DNA Methylation in Prostate Tumors from Puerto Rican Men

In 2020, approximately 191,930 new prostate cancer (PCa) cases are estimated in the United States (US). Hispanic/Latinos (H/L) are the second largest racial/ethnic group in the US. This study aims to assess methylation patterns between aggressive and indolent PCa including DNA repair genes along with ancestry proportions. Prostate tumors classified as aggressive (n = 11) and indolent (n = 13) on the basis of the Gleason score were collected. Tumor and adjacent normal tissue were annotated on H&E (Haemotoxylin and Eosin) slides and extracted by macro-dissection. Methylation patterns were assessed using the Illumina 850K DNA methylation platform. Raw data were processed using the Bioconductor package. Global ancestry proportions were estimated using ADMIXTURE (k = 3). One hundred eight genes including AOX1 were differentially methylated in tumor samples. Regarding the PCa aggressiveness, six hypermethylated genes (RREB1, FAM71F2, JMJD1C, COL5A3, RAE1, and GABRQ) and 11 hypomethylated genes (COL9A2, FAM179A, SLC17A2, PDE10A, PLEKHS1, TNNI2, OR51A4, RNF169, SPNS2, ADAMTSL5, and CYP4F12) were identified. Two significant differentially methylated DNA repair genes, JMJD1C and RNF169, were found. Ancestry proportion results for African, European, and Indigenous American were 24.1%, 64.2%, and 11.7%, respectively. The identification of DNA methylation patterns related to PCa in H/L men along with specific patterns related to aggressiveness and DNA repair constitutes a pivotal effort for the understanding of PCa in this population.

Hypermethylated promoters of genes UNC5D and KCNA1 as potential novel diagnostic biomarkers in colorectal cancer

Aim: Identification of aberrant hypermethylation in promoter regions of candidate genes to discover potential biomarkers for colorectal cancer. Materials & Methods: Genes BMP2, IRF4, KCNA1, LRRC7, NRG3, SLC27A6 and UNC5D were pre-selected in a bioinformatics study for their hypermethylation status in colorectal cancer. Methylation analysis was performed on 202 cancer tissue specimens to validate candidate genes. Results: Genes KCNA1 and UNC5D displayed methylation in 95.3 and 99.7% of The Cancer Genome Atlas dataset samples and in 96 and 98% of our experimentally tested samples, respectively. Conclusion: KCNA1 and UNC5D promoter hypermethylation holds diagnostic biomarker potential in patients with early colorectal cancer.

Association between HIC1 promoter methylation and solid tumor: A meta-analysis

The epigenetic silencing of tumor suppressor genes by promoter methylation plays an increasingly important role in cancer research. A number of studies have reported the contribution of HIC1 promoter methylation towards the occurrence and development of solid tumors, even though HIC1 promoter methylation has also been found in normal and benign tissue samples. We sought to perform a more accurate and comprehensive meta-analysis to assess the association between HIC1 promoter methylation and cancer risk. We searched and retrieved all published studies on HIC1 promoter methylation in PubMed, Google Scholar, Embase, Cochrane Library, and Web of Science databases. After two reviewers checked the studies and extracted the necessary data independently, the meta-analysis was performed using STATA 12.0 software. A total of 14 case-control studies (949 cancer patients, 282 benign, and 371 normal controls) were included in our study. We report a significantly elevated HIC1 promoter methylation in tumor samples compared to normal (OR = 7.02, 95 % CI 3.12-15.78, P < 0.001) and benign controls (OR = 2.69, 95 % CI 1.13-6.42, P = 0.025). Subgroup analysis stratified by ethnicity showed a significantly reduced heterogeneity among North American (I² = 0.0 %, P = 0.502) and European (I² = 33.7 %, P = 0.183) samples. In addition, heterogeneity was significantly reduced among MSP based detection method (I² = 36.4 %, P = 0.139) when samples were stratified based on the methylation detection methods. The overall outcome demonstrated that HIC1 promoter methylation may be involved in the occurrence and development of solid tumors and has the potential to serve as an epigenetic maker in various specific tumors.

Comprehensive analysis of prognosis-related methylated sites in breast carcinoma

Background

Breast carcinoma has become a nonnegligible public health problem in China with its increasing incidence and mortality in woman. As a early event regulating tumorigenesis and development, DNA methylation became one of the focuses of current carcinoma researches on potential diagnostic and therapeutic targets.

Methods

In this study, we comprehensively analyzed the gene expression data and DNA methylation data of breast carcinoma and adjacent normal tissues samples in the Gene Expression Omnibus database. Influences of tumor stage, adjuvant therapy, hormone therapy, and chemotherapy on CpG methylation level were explored by linear regression analysis. Correlations between methylation and gene expression levels were determined by spearman rank correlation analysis. Log‐rank test was applied for determining significance of associations between CpG sites methylation level and breast cancer patients' Kaplan–Meier survival.

Results

A total of 229 CpG sites were found to be significantly associated with tumor stage or treatment, and eight of which were potential markers that affect the survival of breast carcinoma and negatively correlated with their genes' expression levels.

Conclusions

We reported eight CpG sites as potential breast cancer prognosis signatures through comprehensively analyzed gene expression and DNA methylation datasets, and excluding influences of tumor stage and treatment. This should be helpful for breast cancer early diagnosis and treatment.

DNA hypermethylation associated with upregulated gene expression in prostate cancer demonstrates the diversity of epigenetic regulation

Background

Prostate cancer (PCa) has the highest incidence rates of cancers in men in western countries. Unlike several other types of cancer, PCa has few genetic drivers, which has led researchers to look for additional epigenetic and transcriptomic contributors to PCa development and progression. Especially datasets on DNA methylation, the most commonly studied epigenetic marker, have recently been measured and analysed in several PCa patient cohorts. DNA methylation is most commonly associated with downregulation of gene expression. However, positive associations of DNA methylation to gene expression have also been reported, suggesting a more diverse mechanism of epigenetic regulation. Such additional complexity could have important implications for understanding prostate cancer development but has not been studied at a genome-wide scale.

Results

In this study, we have compared three sets of genome-wide single-site DNA methylation data from 870 PCa and normal tissue samples with multi-cohort gene expression data from 1117 samples, including 532 samples where DNA methylation and gene expression have been measured on the exact same samples. Genes were classified according to their corresponding methylation and expression profiles. A large group of hypermethylated genes was robustly associated with increased gene expression (UPUP group) in all three methylation datasets. These genes demonstrated distinct patterns of correlation between DNA methylation and gene expression compared to the genes showing the canonical negative association between methylation and expression (UPDOWN group). This indicates a more diversified role of DNA methylation in regulating gene expression than previously appreciated. Moreover, UPUP and UPDOWN genes were associated with different compartments — UPUP genes were related to the structures in nucleus, while UPDOWN genes were linked to extracellular features.

Conclusion

We identified a robust association between hypermethylation and upregulation of gene expression when comparing samples from prostate cancer and normal tissue. These results challenge the classical view where DNA methylation is always associated with suppression of gene expression, which underlines the importance of considering corresponding expression data when assessing the downstream regulatory effect of DNA methylation.

Identification of TAF1, SAT1, and ARHGEF9 as DNA methylation biomarkers for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a major cause of cancer-related deaths worldwide. More than 90% of primary HCC is HCC. Hepatitis C virus (HCV) infection and alcohol consumption have been widely accepted as two major risk factors for developing HCC. Herein, we aimed to identify DNA methylation genes related to both HCV infection and alcohol consumption. In this study, we identified methylation genes that were associated with the risk of HCV infection and alcohol consumption, respectively, by a large-scale bioinformatic analysis. Through PPI network analysis, we revealed the associations between the two types of genes and found six hub genes-TAF1, SAT1, Phospholipase C-beta 2, FGD1, ARHGAP4, and ARHGEF9-that may be associated with both HCV infection and alcohol consumption. Gene Ontology enrichment analysis was used to analyze the function which these genes in the network enriched. Among them, TAF1, SAT1, and ARHGEF9 were methylated genes that have been found to be related to tumor progression in HCC patients. Through independent data sets, we verified the methylation pattern of these six genes in HCC samples that had both HCV infection and alcohol consumption risks. Furthermore, we found that three of the six methylated genes were also associated with the prognosis of HCC patients. To summarize, we identified six hub genes that were associated with both HCV infection and alcohol consumption in the progress of HCC. The six methylation genes that might play an important role in both HCV infection and alcohol consumption would be potential therapy targets for HCC.

The Gasdermin E Gene Has Potential as a Pan-Cancer Biomarker, While Discriminating between Different Tumor Types

Due to the elevated rates of incidence and mortality of cancer, early and accurate detection is crucial for achieving optimal treatment. Molecular biomarkers remain important screening and detection tools, especially in light of novel blood-based assays. DNA methylation in cancer has been linked to tumorigenesis, but its value as a biomarker has not been fully explored. In this study, we have investigated the methylation patterns of the Gasdermin E gene across 14 different tumor types using The Cancer Genome Atlas (TCGA) methylation data (N = 6502). We were able to identify six CpG sites that could effectively distinguish tumors from normal samples in a pan-cancer setting (AUC = 0.86). This combination of pan-cancer biomarkers was validated in six independent datasets (AUC = 0.84–0.97). Moreover, we tested 74,613 different combinations of six CpG probes, where we identified tumor-specific signatures that could differentiate one tumor type versus all the others (AUC = 0.79–0.98). In all, methylation patterns exhibited great variation between cancer and normal tissues, but were also tumor specific. Our analyses highlight that a Gasdermin E methylation biomarker assay, not only has the potential for being a methylation-specific pan-cancer detection marker, but it also possesses the capacity to discriminate between different types of tumors.

Random forest-based modelling to detect biomarkers for prostate cancer progression

BACKGROUND

The clinical course of prostate cancer (PCa) is highly variable, demanding an individualized approach to therapy. Overtreatment of indolent PCa cases, which likely do not progress to aggressive stages, may be associated with severe side effects and considerable costs. These could be avoided by utilizing robust prognostic markers to guide treatment decisions.

RESULTS

We present a random forest-based classification model to predict aggressive behaviour of prostate cancer. DNA methylation changes between PCa cases with good or poor prognosis (discovery cohort with n = 70) were used as input. DNA was extracted from formalin-fixed tumour tissue, and genome-wide DNA methylation differences between both groups were assessed using Illumina HumanMethylation450 arrays. For the random forest-based modelling, the discovery cohort was randomly split into a training (80%) and a test set (20%). Our methylation-based classifier demonstrated excellent performance in discriminating prognosis subgroups in the test set (Kaplan-Meier survival analyses with log-rank p value < 0.0001). The area under the receiver operating characteristic curve (AUC) for the sensitivity analysis was 95%. Using the ICGC cohort of early- and late-onset prostate cancer (n = 222) and the TCGA PRAD cohort (n = 477) for external validation, AUCs for sensitivity analyses were 77.1% and 68.7%, respectively. Cancer progression-related DNA hypomethylation was frequently located in 'partially methylated domains' (PMDs)-large-scale genomic areas with progressive loss of DNA methylation linked to mitotic cell division. We selected several candidate genes with differential methylation in gene promoter regions for additional validation at the protein expression level by immunohistochemistry in > 12,000 tissue micro-arrayed PCa cases. Loss of ZIC2 protein expression was associated with poor prognosis and correlated with significantly shorter time to biochemical recurrence. The prognostic value of ZIC2 proved to be independent from established clinicopathological variables including Gleason grade, tumour stage, nodal stage and prostate-specific-antigen.

CONCLUSIONS

Our results highlight the prognostic relevance of methylation loss in PMD regions, as well as of several candidate genes not previously associated with PCa progression. Our robust and externally validated PCa classification model either directly or via protein expression analyses of the identified top-ranked candidate genes will support the clinical management of prostate cancer.

Methylation of Glutathione-S-Transferase P1 Promotor in Egyptian Females with Breast Cancer

Background:

Breast cancer (BC) is the second most common cancer after the lung cancer worldwide and number one killing cancer in Egyptian females . It is a multifactorial disease driven by different environmental, hormonal, genetic and epigenetic factors. Epigenetic alterations have been studied in cancer breast. Role of GSTP1 promotor methylation in breast cancer has been studied in different ethnic groups.

Objectives:

Current study aimed at studying the methylation status of the promotor region of glutathione-S-transferase P1 in breast ductal carcinoma of a cohort group of Egyptian females and its correlations with histopathological and prognostic parameters.

Methods:

Control group included 15 fresh normal breast tissues taken from BC female patients after leaving a clearly defined safety margin and a Patient group included confirmed 35 fresh breast ductal carcinoma tissue biopsies taken from female patients postoperatively. To all patients clinical examination, radiological examination (plain X-ray chest and or CT scan, ultrasonography of abdomen and pelvis were done), in addition to histopathological examination, typing, grading and staging of tumour, hormonal receptors status and molecular typing of breast mass. GSTP1 methylation status was evaluated using methyl specific polymerase chain reaction.

Results:

Statistical significant increase was found in methylation status of GSTP1 promotor gene in BC cases than that in control group, (60% of patients samples had methylated GSTP1 promotor vs only 6.7% of controls) (p= >0.001). No association was found between GSTP1 promotor methylation status and the poor prognostic factors neither with hormonal profile nor molecular type. However, GSTP1 promotor methylation were two times higher in postmenopausal than premenopausal cases and three times higher in late grade (III). Also GSTP1 promotor methylation was 2.4 times higher in Her2 positive cases than either ER or PR positive cases. Conclusion: Glutathione-S-Transferase P1 Promotor methylation plays a role in breast cancer development.

Differential gene methylation patterns in cancerous and non‑cancerous cells

Large-scale projects, such as The Cancer Genome Atlas (TCGA), Human Epigenome Project (HEP) and Human Epigenome Atlas (HEA), provide an insight into DNA methylation and histone modification markers. Changes in the epigenome significantly contribute to the initiation and progression of cancer. The goal of the present study was to characterize the prostate cancer malignant transformation model using the CpG island methylation pattern. The Human Prostate Cancer EpiTect Methyl II Signature PCR Array was used to evaluate the methylation status of 22 genes in prostate cancer cell lines: PC3, PC3M, PC3MPro4 and PC3MLN4, each representing different metastatic potential in vivo. Subsequently, it was ascertained whether DNA methylation plays a role in the expression of these genes in prostate cancer cells. Hypermethylation of APC, DKK3, GPX3, GSTP1, MGMT, PTGS2, RASSF1, TIMP2 and TNFRSF10D resulted in downregulation of their expression in prostate cancer cell lines as compared to WT fibroblasts. Mining of the TCGA data deposited in the MetHC database found increases in the methylation status of these 9 genes in prostate cancer patients, further supporting the role of methylation in altering the expression of these genes in prostate cancer. Future studies are warranted to investigate the role of these proteins in prostate cancer development.

Unmethylated promoter DNA correlates with p53 expression and apoptotic levels only in Vitamin B9 and B12 deficient megaloblastic anemia but not in non-megaloblastic anemia controls

Cyanocobalamin (Vitamin B12, VB12) and Folic acid (Vitamin B9, VB9) deficiency leads to anemia in women. We have recently shown low VB12 and VB9 levels in the serum of megaloblastic anemia (MBA) patients. Further, our study demonstrated elevated homocysteine and p53, respectively, in the serum and bone marrow aspirates of MBA patients but not in non-MBA subjects. However, it is unknown whether any gender specific variation in VB12 and VB9 level exists in MBA and non-MBA patients? In addition, it is unclear whether low VB12 and VB9 has a role in the regulation of p53 expression in MBA patients? And whether elevated p53 is functionally active? If so, does bone marrow aspirates of MBA patients show elevated apoptosis. Hence, we have analyzed VB12 and VB9 levels in MBA patients and compared with non-MBA subjects. Next, methylation status of p53 promoter was determined and correlated with p53 expression. Furthermore, the level of apoptosis in bone marrow aspirate paraffin blocks was estimated using TUNEL staining. In conclusion, low VB12 and VB9 in male and female patients directly correlate with p53 promoter unmethylation status, but, inversely correlate with p53 protein expression and its activity, only in MBA cases but not in non-MBA controls.

Identification of key pathways and genes with aberrant methylation in prostate cancer using bioinformatics analysis

Prostate cancer (PCa), a multifocal clinically heterogeneous disease, is the most commonly diagnosed non-cutaneous neoplasm in men worldwide. The epigenome of PCa is a typical representation of catastrophic model of epigenetic alterations during tumorigenesis and its progression. Alterations in methylation patterns in tumor suppressors, cell cycle, oncogenes and metabolism-related genes are the most commonly observed epigenetic alterations in PCa. In this study, we have developed a computational strategy to identify methylated biomarker signature panels as potential targets of PCa by screening >160 genes reported to be epigenetically dysregulated, and shortlisted 26 differentially methylated genes (DMGs) that significantly contribute to oncogenesis. The gene ontology and functional enrichment analysis were performed, which showed that identified DMGs contribute to cellular and metabolic processes such as cell communication, cell cycle, response to drugs, apoptosis and p53 signaling. The top hub genes AR, CDH13, CDKN2A, DAPK1, GSTP1, CD44 and RASSF1 identified from protein-protein interaction network construction using Search Tool for the Retrieval of Interacting Genes contributed to hormonal response, inflammatory response, cell cycle, reactive oxygen species activity and receptor kinase activity, which are related to hallmarks of cancer as revealed by their functional enrichment analysis by Cytoscape. These genes were further scrutinized for CpG islands, transcription start sites and positions of methylated cytosines to study their methylation profiles. Our analysis revealed high negative correlation values between methylation frequencies and gene expressions of the hub genes, namely, AR, CDH13, CDKN2A, DAPK1, CD44, GSTP1 and RASSF1, which can be used as potential diagnostic biomarkers for PCa.

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.

Identification of novel prostate cancer drivers using RegNetDriver: a framework for integration of genetic and epigenetic alterations with tissue-specific regulatory network

We report a novel computational method, RegNetDriver, to identify tumorigenic drivers using the combined effects of coding and non-coding single nucleotide variants, structural variants, and DNA methylation changes in the DNase I hypersensitivity based regulatory network. Integration of multi-omics data from 521 prostate tumor samples indicated a stronger regulatory impact of structural variants, as they affect more transcription factor hubs in the tissue-specific network. Moreover, crosstalk between transcription factor hub expression modulated by structural variants and methylation levels likely leads to the differential expression of target genes. We report known prostate tumor regulatory drivers and nominate novel transcription factors (ERF, CREB3L1, and POU2F2), which are supported by functional validation.

Integrative modelling of tumour DNA methylation quantifies the contribution of metabolism

Altered DNA methylation is common in cancer and often considered an early event in tumorigenesis. However, the sources of heterogeneity of DNA methylation among tumours remain poorly defined. Here we capitalize on the availability of multi-platform data on thousands of human tumours to build integrative models of DNA methylation. We quantify the contribution of clinical and molecular factors in explaining intertumoral variability in DNA methylation. We show that the levels of a set of metabolic genes involved in the methionine cycle is predictive of several features of DNA methylation in tumours, including the methylation of cancer genes. Finally, we demonstrate that patients whose DNA methylation can be predicted from the methionine cycle exhibited improved survival over cases where this regulation is disrupted. This study represents a comprehensive analysis of the determinants of methylation and demonstrates the surprisingly large interaction between metabolism and DNA methylation variation. Together, our results quantify links between tumour metabolism and epigenetics and outline clinical implications.

Altered DNA methylation is a feature of cancer and between-patient variability is prevalent. Here, the authors integrate data on thousands of human tumours, and find that expression levels of methionine metabolism genes are predictive of methylation features, and that the breakdown of this relationship is a negative prognostic marker.

Large-scale evaluation of SLC18A2 in prostate cancer reveals diagnostic and prognostic biomarker potential at three molecular levels

Limitations of current diagnostic and prognostic tools for prostate cancer (PC) have led to over-diagnosis and over-treatment. Here, we investigate the biomarker potential of the SLC18A2 (VMAT2) gene for PC at three molecular levels. Thus, SLC18A2 promoter methylation was analyzed in 767 malignant and 78 benign radical prostatectomy (RP) samples using methylation-specific qPCR and Illumina 450K methylation microarray data. SLC18A2 transcript levels were assessed in 412 malignant and 45 benign RP samples using RNAseq data. SLC18A2 protein was evaluated by immunohistochemistry in 502 malignant and 305 benign RP samples. Cancer-specificity of molecular changes was tested using Mann-Whitney U tests and/or receiver operating characteristic (ROC) analyses. Log rank, uni- and multivariate Cox regression tests were used for survival analyses. We found that SLC18A2 promoter hypermethylation was highly cancer-specific (area under the curve (AUC): 0.923-0.976) and associated with biochemical recurrence (BCR) after RP in univariate analyses. SLC18A2 transcript levels were reduced in PC and had independent prognostic value for BCR after RP (multivariate HR 0.13, P < 0.05). Likewise, SLC18A2 protein was down-regulated in PC (AUC 0.898) and had independent prognostic value for BCR (multivariate HR 0.51, P < 0.05). Reduced SLC18A2 protein expression was also associated with poor overall survival in univariate analysis (HR 0.29, P < 0.05). Our results highlight SLC18A2 as a new promising methylation marker candidate for PC diagnosis. Furthermore, SLC18A2 expression (RNA and protein) showed promising prognostic potential beyond routine clinicopathological variables. Thus, novel SLC18A2-based molecular tests could have useful future applications for PC detection and identification of high-risk patients.

Ability of PITX2 methylation to predict survival in patients with prostate cancer

Background

The aim of this study was to explore whether candidate gene methylation can effectively predict death from prostate cancer.

Methods

After reviewing the literature to identify likely candidate genes, we assembled a case-control cohort (in a 1:2 ratio) to explore the distribution of PITX2, WNT5a, SPARC, EPB41L3, and TPM4 methylation levels. The case group comprised 45 patients with a Gleason score ≤7 who had died as a result of prostate cancer, and the control group comprised 90 current prostate cancer patients or those who died of other causes. The methylation possibility of each of the candidate genes were maximized. Univariate conditional logistic was applied for data analysis and to evaluate prediction efficiency of gene methylation on prostate cancer.

Results

The results indicated that a raised level of PITX2 methylation increased the likelihood of death due to prostate cancer by 10% (odds ratio 1.56, 95% confidence interval 1.17–2.08; P=0.005). Methylation of SPARC was found to be able to distinguish between benign prostate hyperplasia and prostate cancer.

Conclusion

Methylation of PITX2 is an effective biomarker to predict death from prostate cancer, particularly in patients with a low Gleason score.

N6-Methyladenine hinders RNA- and DNA-directed DNA synthesis: application in human rRNA methylation analysis of clinical specimens

N⁶-Methyladenine (m⁶A) is the most abundant internal modification on mammalian mRNA. Very recently, m⁶A has been reported as a potentially important 'epigenetic' mark in eukaryotes. Until now, site-specific detection of m⁶A is technically very challenging. Here, we first reveal that m⁶A significantly hinders DNA- and RNA-directed DNA synthesis. Systematic investigations of 5'-triphosphates of a variety of 5-substituted 2'-deoxyuridine analogs in primer extension have been performed. In the current study, a quantitative analysis of m⁶A in the RNA or DNA context has been achieved, using Bst DNA polymerase catalyzed primer extension. Molecular dynamics study predicted that m⁶A in template tends to enter into and be restrained in the MGR region of Bst DNA polymerase, reducing conformational flexibility of the DNA backbone. More importantly, a site-specific determination of m⁶A in human ribosomal RNA (rRNA) with high accuracy has been afforded. Through a cumulative analysis of methylation alterations, we first reveal that significantly cancer-related changes in human rRNA methylation were present in patients with hepatocellular carcinoma.

Development of Castration Resistant Prostate Cancer can be Predicted by a DNA Hypermethylation Profile

PURPOSE

Detection of DNA hypermethylation has emerged as a novel molecular biomarker for prostate cancer diagnosis and evaluation of prognosis. We sought to define whether a hypermethylation profile of patients with prostate cancer on androgen deprivation would predict castrate resistant prostate cancer.

MATERIALS AND METHODS

Genome-wide methylation analysis was performed using a methylation cancer panel in 10 normal prostates and 45 tumor samples from patients placed on androgen deprivation who were followed until castrate resistant disease developed. Castrate resistant disease was defined according to EAU (European Association of Urology) guideline criteria. Two pathologists reviewed the Gleason score, Ki-67 index and neuroendocrine differentiation. Hierarchical clustering analysis was performed and relationships with outcome were investigated by Cox regression and log rank analysis.

RESULTS

We found 61 genes that were significantly hypermethylated in greater than 20% of tumors analyzed. Three clusters of patients were characterized by a DNA methylation profile, including 1 at risk for earlier castrate resistant disease (log rank p = 0.019) and specific mortality (log rank p = 0.002). Hypermethylation of ETV1 (HR 3.75) and ZNF215 (HR 2.89) predicted disease progression despite androgen deprivation. Hypermethylation of IRAK3 (HR 13.72), ZNF215 (HR 4.81) and SEPT9 (HR 7.64) were independent markers of prognosis. Prostate specific antigen greater than 25 ng/ml, Gleason pattern 5, Ki-67 index greater than 12% and metastasis at diagnosis also predicted a negative response to androgen deprivation. Study limitations included the retrospective design and limited number of cases.

CONCLUSIONS

Epigenetic silencing of the mentioned genes could be novel molecular markers for the prognosis of advanced prostate cancer. It might predict castrate resistance during hormone deprivation and, thus, disease specific mortality. Gene hypermethylation is associated with disease progression in patients who receive hormone therapy. It could serve as a marker of the treatment response.

Epigenetic modulation of Chlorella (Chlorella vulgaris) on exposure to polycyclic aromatic hydrocarbons

DNA methylation in promoter region can be a new chemopreventive marker against polycyclic aromatic hydrocarbons (PAHs). We performed a randomized, double blind and cross-over trial (N=12 healthy females) to evaluate chlorella (Chlorella vulgaris)-induced epigenetic modulation on exposure to PAHs. The subjects consumed 4 tablets of placebo or chlorella supplement (total chlorophyll ≈ 8.3mg/tablet) three times a day before meals for 2 weeks. When the subjects consumed chlorella, status of global hypermethylation (5-methylcytosine) was reduced, compared to placebo (p=0.04). However, DNA methylation at the DNMT1 or NQO1 was not modified by chlorella. We observed the reduced levels of urinary 1-hydroxypyrene (1-OHP), a typical metabolite of PAHs, by chlorella intake (p<0.1) and a positive association between chlorella-induced changes in global hypermethylation and urinary 1-OHP (p<0.01). Therefore, our study suggests chlorella works for PAH-detoxification through the epigenetic modulation, the interference of ADME of PAHs and the interaction of mechanisms.

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.

Serum GADD45a methylation is a useful biomarker to distinguish benign vs malignant prostate disease

BACKGROUND

Prostate-specific antigen (PSA) screening for prostate cancer results in a large number of unnecessary prostate biopsies. There is a need for specific molecular markers that can be used in combination with PSA to improve the specificity of PSA screening. We examined GADD45a methylation in blood DNA as a molecular marker for prostate cancer diagnosis.

METHODS

The study included 82 men, with PSA levels >4 ng ml(-1) and/or abnormal digital rectal exam, who underwent prostate biopsy. We compared GADD45a methylation in DNA from serum and buffy coat in 44 patients (22 prostate cancer and 22 benign). GADD45a methylation in serum DNA was examined in 82 patients (34 cancer and 48 benign).

RESULTS

There was no significant difference in buffy coat GADD45a methylation between cancer and benign patients. Serum GADD45a methylation was significantly higher in cancer than in benign patients. Classification and regression tree predictive model for prostate cancer including risk groups defined by PSA, free circulating DNA (fcDNA) level and GADD45a methylation yielded specificity of 87.5%, sensitivity of 94.1% and receiver operator characteristic curve area of 0.937.

CONCLUSIONS

Serum GADD45a methylation in combination with PSA and fcDNA level was useful in distinguishing benign from prostate cancer patients.

De novo assembly of a haplotype-resolved human genome

The human genome is diploid, and knowledge of the variants on each chromosome is important for the interpretation of genomic information. Here we report the assembly of a haplotype-resolved diploid genome without using a reference genome. Our pipeline relies on fosmid pooling together with whole-genome shotgun strategies, based solely on next-generation sequencing and hierarchical assembly methods. We applied our sequencing method to the genome of an Asian individual and generated a 5.15-Gb assembled genome with a haplotype N50 of 484 kb. Our analysis identified previously undetected indels and 7.49 Mb of novel coding sequences that could not be aligned to the human reference genome, which include at least six predicted genes. This haplotype-resolved genome represents the most complete de novo human genome assembly to date. Application of our approach to identify individual haplotype differences should aid in translating genotypes to phenotypes for the development of personalized medicine.

Integrative analysis of DNA methylation and gene expression data identifies EPAS1 as a key regulator of COPD

Chronic Obstructive Pulmonary Disease (COPD) is a complex disease. Genetic, epigenetic, and environmental factors are known to contribute to COPD risk and disease progression. Therefore we developed a systematic approach to identify key regulators of COPD that integrates genome-wide DNA methylation, gene expression, and phenotype data in lung tissue from COPD and control samples. Our integrative analysis identified 126 key regulators of COPD. We identified EPAS1 as the only key regulator whose downstream genes significantly overlapped with multiple genes sets associated with COPD disease severity. EPAS1 is distinct in comparison with other key regulators in terms of methylation profile and downstream target genes. Genes predicted to be regulated by EPAS1 were enriched for biological processes including signaling, cell communications, and system development. We confirmed that EPAS1 protein levels are lower in human COPD lung tissue compared to non-disease controls and that Epas1 gene expression is reduced in mice chronically exposed to cigarette smoke. As EPAS1 downstream genes were significantly enriched for hypoxia responsive genes in endothelial cells, we tested EPAS1 function in human endothelial cells. EPAS1 knockdown by siRNA in endothelial cells impacted genes that significantly overlapped with EPAS1 downstream genes in lung tissue including hypoxia responsive genes, and genes associated with emphysema severity. Our first integrative analysis of genome-wide DNA methylation and gene expression profiles illustrates that not only does DNA methylation play a ‘causal’ role in the molecular pathophysiology of COPD, but it can be leveraged to directly identify novel key mediators of this pathophysiology.

Chronic Obstructive Pulmonary Disease (COPD) is a common lung disease. It is the fourth leading cause of death in the world and is expected to be the third by 2020. COPD is a heterogeneous and complex disease consisting of obstruction in the small airways, emphysema, and chronic bronchitis. COPD is generally caused by exposure to noxious particles or gases, most commonly from cigarette smoking. However, only 20–25% of smokers develop clinically significant airflow obstruction. Smoking is known to cause epigenetic changes in lung tissues. Thus, genetics, epigenetic, and their interaction with environmental factors play an important role in COPD pathogenesis and progression. Currently, there are no therapeutics that can reverse COPD progression. In order to identify new targets that may lead to the development of therapeutics for curing COPD, we developed a systematic approach to identify key regulators of COPD that integrates genome-wide DNA methylation, gene expression, and phenotype data in lung tissue from COPD and control samples. Our integrative analysis identified 126 key regulators of COPD. We identified EPAS1 as the only key regulator whose downstream genes significantly overlapped with multiple genes sets associated with COPD disease severity.

Epigenetics in breast and prostate cancer

Most recent investigations into cancer etiology have identified a key role played by epigenetics. Specifically, aberrant DNA and histone modifications which silence tumor suppressor genes or promote oncogenes have been demonstrated in multiple cancer models. While the role of epigenetics in several solid tumor cancers such as colorectal cancer are well established, there is emerging evidence that epigenetics also plays a critical role in breast and prostate cancer. In breast cancer, DNA methylation profiles have been linked to hormone receptor status and tumor progression. Similarly in prostate cancer, epigenetic patterns have been associated with androgen receptor status and response to therapy. The regulation of key receptor pathways and activities which affect clinical therapy treatment options by epigenetics renders this field high priority for elucidating mechanisms and potential targets. A new set of methylation arrays are now available to screen epigenetic changes and provide the cutting-edge tools needed to perform such investigations. The role of nutritional interventions affecting epigenetic changes particularly holds promise. Ultimately, determining the causes and outcomes from epigenetic changes will inform translational applications for utilization as biomarkers for risk and prognosis as well as candidates for therapy.

ZNF695 methylation predicts a response of esophageal squamous cell carcinoma to definitive chemoradiotherapy

PURPOSE

Definitive chemoradiotherapy (dCRT) is one of the standard treatments for esophageal squamous cell carcinoma. Patients with a response to dCRT have a better prognosis than those resistant to dCRT while survival benefits for patients with residual tumors are limited. Nevertheless, few molecular markers to predict the response to dCRT are currently available. Here, we aimed to establish a DNA methylation marker to predict the response to dCRT.

METHODS

A total of 104 patients were divided into screening (n = 43) and validation (n = 61) sets. A genome-wide DNA methylation analysis was performed using an Infinium HumanMethylation450 BeadChip array. Methylation levels were measured by quantitative methylation-specific PCR and normalized by the fraction of cancer cells in a sample.

RESULTS

The genome-wide methylation analysis of seven responders and eight non-responders identified 18 genomic regions specifically (un)methylated in the responders. Among these, methylation of the promoter CpG island of ZNF695 was significantly associated with the response to dCRT in the screening set (P = 0.004), and a cutoff value was determined. In the validation set, the association was successfully validated (P = 0.021), and a high specificity (90 %) for the prediction of responders was obtained using the prefixed cutoff value. In addition, a multivariate analysis showed that ZNF695 methylation was an independent predictive factor for the response to dCRT (OR 7.55, 95 % CI 2.12-26.9, P = 0.002).

CONCLUSION

ZNF695 methylation was significantly associated with the response to dCRT and is a promising predictive marker for the response to dCRT.