Bisulfite-converted DNA Research Articles

Blood Plasma Methylated DNA Markers in the Detection of Lymphoma: Discovery, Validation, and Clinical Pilot.

Lymphoma is one of the leading causes of cancer and cancer deaths and yet has not been amenable to population screening. The role of methylated DNA markers (MDMs) in the detection of lymphoma has not been extensively studied. We aimed to discover, validate, and test tissue-derived MDMs of lymphoma in archival plasma specimens. Reduced representation bisulfite sequencing (RRBS) was performed on a discovery set of frozen tissues. MDMs identified were converted to methylation-specific PCR assays and validated on independent formalin-fixed, paraffin-embedded (FFPE) tissues. Target enrichment long-probe quantitative-amplified signal (TELQAS) assays were developed and assayed in plasma-extracted, bisulfite-converted DNA from independent treatment-naïve lymphoma patients and healthy controls. Prediction of cancer status was modeled using random forest model with in silico cross-validation. After discovery and validation in tissue, 16 TELQAS assays (ZNF503, VWA5B1, HOXA9, GABRG3, ITGA5, MAX.chr17.7190, BNC1, CDK20, MAX.chr4.4069, TPBG, DNAH14, SYT6, CACNG8, FAM110B, ADRA1D, and NRN1) were selected for testing in plasma. These detected 78% (95% CI, 74%-82%) of lymphoma cases at 90% specificity. Excluding marginal zone and T-cell lymphomas, sensitivity increased to 84% (80%-88%). MDMs in plasma show promise to detect lymphoma and are candidates for inclusion in multi-cancer detection studies.

Abstract A014: A methylation state specific targeted background depletion technique for enrichment of ctDNA fraction

Abstract Liquid biopsy continues to be a focus of the cancer diagnostics industry, primarily due to the non-invasive nature of sample collection, however the low levels of circulating tumor DNA (ctDNA) remain a challenge. Methylation has emerged as a promising biomarker for detecting ctDNA, yet detecting the cancerous signal in an excess of non-cancerous, unmethylated cfDNA in the background has been proven difficult. Harbinger Health has developed a novel method that depletes unmethylated background at the CpG-level from specific genomic regions of interest, resulting in an enrichment of the ctDNA fraction. We developed a background cfDNA depletion method that utilizes the endonuclease activity and the specificity of CRISPR/Cas12a to remove unmethylated DNA fragments at ctDNA methylation biomarker sites. First, we identified cancer-informative regions that showed consistent contiguous elevated methylation states in cancer compared to normal samples. We then designed guide RNAs that specifically bind and cut unmethylated CpG sites within the target regions. Cas depletion of bisulfite-converted DNA enriches cancer informative signal for bioanalysis. To test validity of our Cas complex designs, we created model samples that mimic fully unmethylated and fully methylated species. We spiked these cfDNA models into a background of genomic DNA from 5% to 0.01%. In triplicate, we examined cutting efficiency, multiplexing and specificity of Cas to unmethylated species of model DNA. Results were assessed using qPCR by comparing differences in Ct with and without Cas treatment. Additionally, we applied this depletion step during our library preparation process to show utility in methylation analysis of low tumor content liquid biopsy samples. Using both the model sample dilution series and bisulfite converted cfDNA samples, which represent a range of cancerous and background methylation signal, we deplete unmethylated targets using Cas prior to indexing PCR. This rendered unmethylated targets non-amplifiable, removing them from analysis. Results were assessed using both qPCR and sequencing data, such as methylated read counts over the target region. We demonstrated our analytical approach efficiently depletes non-cancer cfDNA by on average 9-fold, which increases the fraction of ctDNA signal and can be multiplexed. This background signal depletion driven by CRISPR is sensitive and specific, maintaining methylated DNA signal detection down to 0.01% at inputs of 10ng DNA. Our Cas-mediated depletion of background signal method has proven useful for enriching rare methylated fragments over background by improving the signal to noise ratio. This technique is novel by harnessing the specificity of CRISPR to target DNA in both a sequence and methylation state specific manner. The depletion of precise methylation states at the CpG-level make it suitable for use in multiple bioassays. Citation Format: Caitlin Gilley, Miguel Williams, Emily Neaga, Sarah Falotico, Kade Pettie, Anthony Shuber. A methylation state specific targeted background depletion technique for enrichment of ctDNA fraction [abstract]. In: Proceedings of the AACR Special Conference: Liquid Biopsy: From Discovery to Clinical Implementation; 2024 Nov 13-16; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(21_Suppl):Abstract nr A014.

Multimodal Pancreatic Cancer Detection Using Methylated DNA Biomarkers in Pancreatic Juice and Plasma CA 19-9: A Prospective Multicenter Study

Background and AimsIn previous studies methylated DNA markers (MDMs) have been identified in pancreatic juice (PJ) for detecting pancreatic ductal adenocarcinoma (PDAC). In this prospective multicenter study, the sensitivity and specificity characteristics of this panel of PJ-MDMs was evaluated standalone and in combination with plasma CA 19-9. MethodsPaired PJ and plasma were assayed from 88 biopsy-proven treatment naïve PDAC cases and 134 controls (normal pancreas: 53, chronic pancreatitis (CP): 23, intraductal papillary mucinous neoplasm (IPMN): 58). Bisulfite-converted DNA from buffered PJ was analyzed using long-probe quantitative amplified signal assay targeting 14 MDMs (NDRG4, BMP3, TBX15, C13orf18, PRKCB, CLEC11A, CD1D, ELMO1, IGF2BP1, RYR2, ADCY1, FER1L4, EMX1, and LRRC4) and a reference gene (methylated B3GALT6). Logistic regression was used to fit the previously identified 3-MDM PJ panel (FER1L4, C13orf18 and BMP3). Discrimination accuracy was summarized using area under the receiver operating characteristic curve (AUROC) with corresponding 95% confidence intervals. ResultsMethylated FER1L4 had the highest individual AUROC of 0.83 (95% CI: 0.78-0.89). The AUROC for the 3-MDM PJ + Plasma CA 19-9 model (0.95 (0.92-0.98))) was higher than both the 3-MDM PJ panel (0.87 (0.82-0.92)) and plasma CA 19-9 alone ((0.91 (0.87-0.96) (p=0.0002 and 0.0135, respectively). At a specificity of 88% (95% CI: 81-93%), the sensitivity of this model was 89% (80-94%) for all PDAC stages and 83% (64-94%) for stage I/II PDAC. ConclusionA panel combining PJ-MDMs and plasma CA19-9 discriminates PDAC from both healthy and disease control groups with high accuracy. This provides support for combining pancreatic juice and blood-based biomarkers for enhancing diagnostic sensitivity and successful early PDAC detection.

Methylation, Gene Expression, and Risk Genotypes at the TERT-CLPTM1L Locus in Cervical Cancer.

The reverse transcriptase subunit of telomerase, TERT, is frequently activated in high-grade dysplasia and invasive cancers of the uterine cervix. Telomerase activation through hypomethylation of the TERT promoter holds promise as a biomarker for cervical cancer progression, however, specific CpG sites involved in cervical cancer risk remain to be fully defined. A recent genome-wide association study on cervical cancer identified genetic polymorphisms at 5p13.33 (close to TERT-CLPTM1L) but the underlying mechanisms are undetermined. We investigated 529 CpG sites within the TERT promoter region and 3 CpG islands nearby, and 21 CpG sites within CLPTM1L in 190 bisulfite-converted cervical tumor DNA samples from BioRAIDs (NCT02428842). We identified eight CpG sites within TERT intron 2 where methylation was significantly associated with the genotypes of cervical cancer risk variants rs27070 and rs459961 in cervical tumors after multiple testing correction (p < 9.4 × 10E-5). Hypermethylation at chr5:1289663 correlated with decreased TERT mRNA levels. In an independent series of 188 normal or dysplastic cervical tissues, rare alleles of rs27070 and rs459961 were associated with low basal CLPTM1L levels and with the absence of TERT mRNA in HPV-negative samples, consistent with their proposed role as protective variants for cervical cancer. HPV infection was associated with increased CLPTM1L and TERT levels. Collectively, our results provide a link between cervical cancer risk variants, methylation, and gene expression and implicate both TERT and CLPTM1L as genes modulated by genomic background and HPV infection during cervical cancer development.

Promoter Hypermethylation of the BRCA1 Gene as a Novel Biomarker for Prostate Cancer.

Prostate cancer (PCa) is recognized as one of the most common malignancies that greatly affects the male population globally. Breast cancer gene 1 (BRCA1) is an important tumor suppressor gene that plays a central role in the maintenance of genomic integrity by promoting the repair of double-strand breaks of DNA. Here, we present a pilot study to examine the promoter methylation and gene expression of the BRCA1 gene in patients with PCa in Erbil governorate, Iraq. The collection of samples took place in Erbil City, Iraq, specifically at Rizgary Hospital, PAR Hospital, and Al-Mufti's private laboratory. A total of 40 tissue samples were collected from age-matched individuals, comprising 30 pathologically confirmed PCa cases and 10 normal prostatic tissue taken from individuals who, during diagnosis, were found to be negative for PCa. Data on demographic and clinical information, such as pathological stage, age, and prostate-specific antigen (PSA) level, were gathered from the medical records. The impact of the promoter methylation was forecasted using the DNA bisulfite conversion technique and methyl-specific PCR (MSP) with specific primers for the BRCA1 promoter region. The assessment of BRCA1 expression was conducted using quantitative real-time PCR (qPCR). Among the 30 patients examined, 76.6% (23 cases) were found to have BRCA1 promoter methylation, and none of the normal tissues appeared to have DNA methylation. BRCA1 promoter methylation was positively associated with the advanced stage of disease (p=0.01) and Gleason score (p=0.007). The analysis revealed a significant downregulation of the BRCA1 gene expression in methylated tumor samples as compared to non-methylated tumors and normal tissues, suggesting the role of epigenetic silencing. To the best of our knowledge, this is the first study investigating methylation status and level of BRCA1 mRNA transcripts among PCa patients in Iraq. Our findings suggest that promoter hypermethylation of the BRCA1 gene could serve as a viable biomarker for PCa, marking a significant discovery.

Intrauterine hyperglycaemia during late gestation caused mitochondrial dysfunction in skeletal muscle of male offspring through CREB/PGC1A signaling

BackgroundMaternal diabetes mellitus can influence the development of offspring. Gestational diabetes mellitus (GDM) creates a short-term intrauterine hyperglycaemic environment in offspring, leading to glucose intolerance in later life, but the long-term effects and specific mechanism involved in skeletal muscle dysfunction in offspring remain to be clarified.MethodsPregnant mice were divided into two groups: The GDM group was intraperitoneally injected with 100 mg/kg streptozotocin on gestational days (GDs) 6.5 and 12.5, while the control (CTR) group was treated with vehicle buffer. Only pregnant mice whose random blood glucose level was higher than 16.8 mmol/L beginning on GD13.5 were regarded as the GDM group. The growth of the offspring was monitored, and the glucose tolerance test was performed at different time points. Body composition analysis and immunohistochemical methods were used to evaluate the development of lean mass at 8 weeks. The exercise capacity and grip strength of the male mouse offspring were assessed at the same period. Transmission electron microscopy was used to observe the morphology inside skeletal muscle at 8 weeks and as a foetus. The genes and proteins associated with mitochondrial biogenesis and oxidative metabolism were investigated. We also coanalyzed RNA sequencing and proteomics data to explore the underlying mechanism. Chromatin immunoprecipitation and bisulfite-converted DNA methylation detection were performed to evaluate this phenomenon.ResultsShort-term intrauterine hyperglycaemia inhibited the growth and reduced the lean mass of male offspring, leading to decreased endurance exercise capacity. The myofiber composition of the tibialis anterior muscle of GDM male offspring became more glycolytic and less oxidative. The morphology and function of mitochondria in the skeletal muscle of GDM male offspring were destroyed, and coanalysis of RNA sequencing and proteomics of foetal skeletal muscle showed that mitochondrial elements and lipid oxidation were consistently impaired. In vivo and in vitro myoblast experiments also demonstrated that high glucose concentrations impeded mitochondrial organisation and function. Importantly, the transcription of genes associated with mitochondrial biogenesis and oxidative metabolism decreased at 8 weeks and during the foetal period. We predicted Ppargc1α as a key upstream regulator with the help of IPA software. The proteins and mRNA levels of Ppargc1α in the skeletal muscle of GDM male offspring were decreased as a foetus (CTR vs. GDM, 1.004 vs. 0.665, p = 0.002), at 6 weeks (1.018 vs. 0.511, p = 0.023) and 8 weeks (1.006 vs. 0.596, p = 0.018). In addition, CREB phosphorylation was inhibited in GDM group, with fewer activated pCREB proteins binding to the CRE element of Ppargc1α (1.042 vs. 0.681, p = 0.037), Pck1 (1.091 vs. 0.432, p = 0.014) and G6pc (1.118 vs. 0.472, p = 0.027), resulting in their decreased transcription. Interestingly, we found that sarcopenia and mitochondrial dysfunction could even be inherited by the next generation.ConclusionsShort-term intrauterine hyperglycaemia significantly reduced lean mass in male offspring at 8 weeks, resulting in decreased exercise endurance and metabolic disorders. Disrupted organisation and function of the mitochondria in skeletal muscle were also observed among them. Foetal exposure to hyperglycaemia decreased the ratio of phosphorylated CREB and reduced the transcription of Ppargc1α, which inhibited the transcription of downstream genes involving in mitochondrial biogenesis and oxidative metabolism. Abnormal mitochondria, which might be transmitted through aberrant gametes, were also observed in the F2 generation.

Methylation of a group of microRNA genes as a marker for the diagnosis and prognosis of non-small cell lung cancer

Objectives. Lung cancer, representing a difficult-to-diagnose heterogeneous malignant neoplasm, is characterized by an asymptomatic course up to late stages, a high incidence of adverse outcomes, and a high probability of metastasis. Its most common form is non-small cell lung cancer (NSCLC). Recent studies have demonstrated a significant role of non-coding RNAs—in particular, microRNAs—in the development of NSCLC. MicroRNAs, which function as post-transcriptional regulators of the expression of protein-coding genes, including those associated with oncogenesis, are involved in the processes of cell proliferation, differentiation, and apoptosis. One of the approaches for regulating the expression of microRNAs themselves is to change the methylation of the CpG island adjacent to the microRNA gene or overlapping it. It has been shown that microRNA genes are several times more likely to undergo methylation than protein-coding genes. The aim of the present work is to study changes in the level of methylation of a number of microRNA genes and compile a potential panel of markers for the diagnosis and prognosis of NSCLC.Methods. Samples of NSCLC tumors were collected and clinically characterized at the Blokhin National Medical Research Center of Oncology, Ministry of Health of the Russian Federation, Moscow, Russia. High-molecular-weight DNA was isolated from tissues using a standard method. The level of methylation was analyzed using bisulfite conversion of DNA and quantitative methyl-specific polymerase chain reaction with real-time detection. The significance of differences between the studied groups was assessed by the nonparametric Mann–Whitney U test for independent samples. Differences were considered significant at p &lt; 0.05.Results. The analysis of methylation levels of microRNA genes revealed a significant (p &lt; 0.05) increase in the methylation level of eight microRNA genes: MIR124-1/2/3, MIR125В-1, MIR129-2, MIR137, MIR375, MIR1258, and MIR339 (p &lt; 0.01, false discovery rate ≤ 0.25). On the basis of receiver operating characteristic analysis, a panel of markers is proposed for the diagnosis of NSCLC according to the nature of methylation of the studied microRNA genes in the tumor and in the normal tissue.Conclusions. Our results, which contribute to the understanding of molecular mechanisms involved in NSCLC development, can be used in the development of new diagnostic and prognostic approaches in clinical oncology.

Diagnostic Accuracy of DNA-Methylation in Detection of Cervical Dysplasia: Findings from a Population-Based Screening Program.

Epigenetic biomarkers in cancer have emerged as promising tools for early detection, prognosis, and treatment response prediction. In cervical cells, hypermethylation of the host and viral HPV-genome increases with the severity of lesions, providing a useful biomarker in the triage of hr-HPV-positive women and during treatment. The present study focuses on evaluating the clinical performance of the FAM19A4/miR124-2 methylation test in a population-based cervical screening program. Previously collected cervical samples, after bisulfite-converted DNA, were analyzed by PreCursor-M+ kit (distributed by Fujirebio Europe), for DNA methylation. The sensitivity, specificity, and negative/positive predictive values of DNA methylation were compared to histology, colposcopy, the HPV-DNA test, and cytology results. Among the 61-sample set, the specificity of methylation vs. positive histology (≥CIN2) and colposcopy (≥G2) were 87% and 90%, whereas the sensitivity was 50% and 33.3%, respectively. The combination of methylation analysis with standard methods increases diagnostic accuracy. Overall, we found a good specificity of DNA methylation in comparison to currently used techniques. Further larger studies could support the use of FAM19A4/miR124-2 as reliable biomarkers in the prevention of cervical cancer as triage in the screening protocol.

FAM19A4 and hsa-miR124-2 Double Methylation as Screening for ASC-H- and CIN1 HPV-Positive Women.

The DNA methylation levels of host cell genes increase with the severity of the cervical intraepithelial neoplasia (CIN) grade and are very high in cervical cancer. Our study aims to evaluate FAM19A4 and hsa-miR124-2 methylation in Atypical Squamous cells with high-grade squamous intraepithelial lesions (ASC-H) and in CIN1, defined as low-grade squamous intraepithelial lesions (LSILs) by the Bethesda classification, as possible early warning biomarkers for managing women with high-risk HPV infections (hrHPV). FAM19A4 and hsa-miR124-2 methylation tests were conducted on fifty-six cervical screening samples from a subset of women aged 30-64 years old. Specimens were collected into ThinPrep PreservCyt Solution. Their HrHPV genotype and cytology diagnosis were known. A Qiasure (Qiagen) was used for FAM19A4 and hsa-miR124-2 methylation testing on bisulfite-converted DNA, according to the manufacturer's specifications. The reported results were hypermethylation-positive or -negative. We found that FAM194A4 and hsa-miR124-2 methylation was detected in 75% of ASC-H cases with a persistent infection of hrHPV. A total of 60% of CIN1 lesions were found to be positive for methylation, and 83.3% were when the cytology was CIN2/3. In addition, as a novelty of this pilot study, we found that combined FAM19A4 and hsa-miR124-2 methylation positivity rates (both methylated) were associated with the HPV genotypes 16, 18, and 59 and covered 22 and 25% of ASC-H and CIN1 cases, respectively. The methylation of these two genes, in combination with HPV genotyping, can be used as an early warning biomarker in the management and follow-up of women with ASC-H and CIN1 to avoid their progression to cervical cancer.

Aberrant methylation of placental development genes in chorionic villi of spontaneous abortions with trisomy 16.

In humans, aneuploidy is incompatible with the birth of healthy children and mainly leads to the death of embryos in the early stages of development in the first trimester of pregnancy. Trisomy 16 is the most common aneuploidy among spontaneous abortions of the first trimester of pregnancy. However, the mechanisms leading to the death of embryos with trisomy 16 remain insufficiently investigated. One of these potential mechanisms is abnormal placental development, including aberrant remodeling of spiral arteries. Spiral artery remodeling involves the migration of trophoblast cells into the maternal spiral arteries, replacing their endothelium and remodeling to ensure a stable embryonic nutrition and oxygen supply. This is a complex process which depends on many factors from both the embryo and the mother. We analyzed the methylation level of seven genes (ADORA2B, NPR3, PRDM1, PSG2, PHTLH, SV2C, and TICAM2) involved in placental development in the chorionic villi of spontaneous abortions with trisomy 16 (n = 14), compared with spontaneous abortions with a normal karyotype (n = 31) and the control group of induced abortions (n = 10). To obtain sequencing libraries, targeted amplification of individual gene regions using designed oligonucleotide primers for bisulfite-converted DNA was used. The analysis was carried out using targeted bisulfite massive parallel sequencing. In the group of spontaneous abortions with trisomy 16, the level of methylation of the PRDM1 and PSG2 genes was significantly increased compared to induced abortions (p = 0.0004 and p = 0.0015, respectively). In the group of spontaneous abortions, there was no increase in the level of methylation of the PRDM1 and PSG2 genes, but the level of methylation of the ADORA2B gene was significantly increased compared to the induced abortions (p = 0.032). The results obtained indicate the potential mechanisms of the pathogenetic effect of trisomy 16 on the placental development with the participation of the studied genes.

Abstract 7001: Profiling the CpG methylation patterns of Epstein-Barr virus DNA in lymphoma patients from Ethiopia

Abstract Introduction: Epstein-Barr virus (EBV) is a tumor virus associated with various malignancies, driven by genetic mutations and epigenetic alterations, including DNA methylation. Abnormal CpG methylation holds promise as a diagnostic and therapeutic biomarker for EBV-associated tumors. However, the understanding of EBV's epigenetic mechanisms remain limited. Determining the methylation profile of EBV is crucial for gaining insights into the pathogenesis of EBV-associated tumors, developing diagnostic biomarkers, and exploring potential therapeutic strategies. Therefore, our study aimed to assess the CpG methylation profile of EBV DNA in lymphoma patients from Ethiopia. Methods: This study enrolled 115 lymphoma patients from Tikur Anbessa Specialized Hospital in Addis Ababa, Ethiopia. Plasma and formalin-fixed paraffin-embedded blocks were collected from the participants, and isolation of DNA was performed from these samples. The methylation analysis was performed using the methylation-iPLEX assay. iPLEX capture and extension primers were designed to amplify and target EBV CpGs from bisulfite-converted DNA sequences. Ethical approval was also obtained from respected institutions. Results: Among the 115 participants, 65.2% (n = 75) were male patients. The largest proportion (n = 35, 30.4%) fell within the 41-60 age group. Non-Hodgkin lymphoma (NHL) was diagnosed in 96 patients, while 19 had Hodgkin lymphoma (HL). In the NHL group, the majority (n = 27, 28.1%) were classified as diffuse large cell lymphoma, followed by follicular lymphoma (n = 24, 25%). Out of the different EBV genome methylation sites, we have identified 24 EBV genes to assess the methylation status of the EBV genome. Average methylation levels of these genes were ranged from 45% to 50%. Notably, the HL group exhibited significant heterogeneity in methylation levels, while the CpG methylation status of EBV genes in NHL subtypes demonstrated a consistent pattern. A significant proportion of our samples exhibited methylation loss in the lytic gene BZLF1 and at the origin of replication associated with lytic replication. Conclusions: This study presents the first data from East Africa, shedding light on the EBV DNA methylation status in a diverse group of lymphoma patients. Further investigations in different locations are necessary to elucidate the impact of EBV DNA methylation on tumor progression. Citation Format: Seifegebriel T. Feleke, Kidist Z. Shita, Abdulaziz A. Sherif, Fisihatsion T. Woldegebriel, Christoph Weigel, Elshafa H. Ahmed, Tamrat A. Zeleke, Robert A. Baiocchi. Profiling the CpG methylation patterns of Epstein-Barr virus DNA in lymphoma patients from Ethiopia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7001.

Methylation‑sensitive restriction enzyme‑droplet digital PCR assay for the one‑step highly sensitive analysis of DNA methylation hotspots.

DNA methylation is an epigenetic modification that plays a key role in several cellular processes mediating the fine regulation of gene expression. Aberrant DNA methylation is observed in a wide range of pathologies, including cancer. Since these DNA modifications are transferred to the cell progenies and are stable over the time, the analysis of DNA methylation status has been proposed for diagnostic and prognostic purposes in cancer. Currently, DNA bisulfite conversion is the gold standard method for the high‑throughput analysis of DNA methylation alterations. However, bisulfite treatment induces DNA fragmentation affecting its quality for the downstream analyses. In this field, it is mandatory to identify novel methods to overcome the limits of conventional approaches. In the present study, the Methylation‑Sensitive Restriction Enzyme‑droplet digital PCR (MSRE‑ddPCR) assay was developed as a novel sensitive method for the analysis of DNA methylation of short genomic regions, combining the MSRE assay with the high‑sensitivity ddPCR and using an exogenous methylation sequence as control. Setup and validation experiments were performed analyzing a methylation hotspot of the Solute Carrier Family 22 Member 17 in DNA samples derived from melanoma cell lines as well as from tissues and serum samples obtained from patients with melanoma and healthy controls. Compared with the standard MSRE approaches, the MSRE‑ddPCR assay is more appropriate for the analysis of DNA methylation (methDNA) in samples with low amounts of DNA (up to 0.651 ng) showing a greater sensitivity. These findings suggested the potential clinical application of MSRE‑ddPCR paving the way to the analysis of other methDNA hotspots in different tumors.

Nrf2 pre-recruitment at Enhancer 2 is a hallmark of H2O2-induced epigenetic transcriptional memory in the HMOX1 gene in human umbilical artery endothelial cells.

Maternal obesity (MO) is a significant cause of increased cardiometabolic risk in offspring, who present endothelial dysfunction at birth. Alterations in physiologic and cellular redox status are strongly associated with altered gene regulation in arterial endothelium. However, specific mechanisms by which the pro-oxidant fetal environment in MO could modulate the vascular gene expression and function during the offspring's postnatal life are elusive. We tested if oxidative stress could reprogram the antioxidant-coding gene's response to a pro-oxidant challenge through an epigenetic transcriptional memory (ETM) mechanism. A pro-oxidant double-hit protocol was applied to human umbilical artery endothelial cells (HUAECs) and EA.hy 926 endothelial cell lines. The ETM acquisition in the HMOX1 gene was analyzed by RT-qPCR. HMOX1 mRNA decay was evaluated by Actinomycin-D treatment and RT-qPCR. To assess the chromatin accessibility and the enrichment of NRF2, RNAP2, and phosphorylation at serin-5 of RNAP2, at HMOX1 gene regulatory regions, were used DNase HS-qPCR and ChIP-qPCR assays, respectively. The CpG methylation pattern at the HMOX1 core promoter was analyzed by DNA bisulfite conversion and Sanger sequencing. Data were analyzed using two-way ANOVA, and p < 0.05 was statistically significant. Using a pro-oxidant double-hit protocol, we found that the Heme Oxygenase gene (HMOX1) presents an ETM response associated with changes in the chromatin structure at the promoter and gene regulatory regions. The ETM response was characterized by a paused-RNA Polymerase 2 and NRF2 enrichment at the transcription start site and Enhancer 2 of the HMOX1 gene, respectively. Changes in DNA methylation pattern at the HMOX1 promoter were not a hallmark of this oxidative stress-induced ETM. These data suggest that a pro-oxidant milieu could trigger an ETM at the vascular level, indicating a potential epigenetic mechanism involved in the increased cardiovascular risk in the offspring of women with obesity.

A high-throughput droplet digital PCR system aiming eight DNA methylation targets for age prediction

The droplet digital Polymerase Chain Reaction (ddPCR) has garnered recognition for its distinctive attribute of absolute quantification. And it has found practical utility in age prediction through DNA methylation profiles. However, a prevalent limitation in current ddPCR methodologies is the restricted capacity to detect only two targets concurrently in most instruments, leading to high costs, sample wastage, and labor-intensive procedures. To address the limitations, a novel high-throughput ddPCR system allowing for the simultaneous detection of eight targets was developed. Through the implementation of a new 8-plex ddPCR assay, coupled with comprehensive linear regression analyses involving primers and probes ratios, diverse inputs of single CpG sites with distinct primers and probes, and varying plex assay configurations, stable DNA methylation values for four CpGs and stable measurement precisions for distinct multiplex systems were consistently observed. These findings pave the way for advancing the field of chemistry science by enabling more efficient and cost-effective methods. Furthermore, the comparative validation of ddPCR and SNaPshot demonstrated a remarkable concordance in results, and the system also displayed well in the field of various aspects, including species specificity, DNA input, and aged samples. In this study, the recommended input of bisulfite-converted DNA was determined to be 10-50ng due to the double-positive droplets. Notably, the Pearson correlation coefficient squared values of four CpGs were 0.4878 (ASPA), 0.4832 (IGSF1), 0.6881 (COL1A1), and 0.6475 (MEIS1-AS3). And the testing set exhibited a mean absolute error of 4.5923 years, indicating the robustness and accuracy of the age-predictive model.

Amplicon-Based Bisulfite Conversion-NGS DNA Methylation Analysis Protocol.

DNA methylation is an important epigenetic modification that regulates chromatin structure and the cell-type-specific expression of genes. The association of aberrant DNA methylation with many diseases, as well as the increasing interest in modifying the methylation mark in a directed manner at genomic sites using epigenome editing for research and therapeutic purposes, increases the need for easy and efficient DNA methylation analysis methods. The standard approach to analyze DNA methylation with a single-cytosine resolution is bisulfite conversion of DNA followed by next-generation sequencing (NGS). In this chapter, we describe a robust, powerful, and cost-efficient protocol for the amplification of target regions from bisulfite-converted DNA, followed by a second PCR step to generate libraries for Illumina NGS. In the two consecutive PCR steps, first, barcodes are added to individual amplicons, and in the second PCR, indices and Illumina adapters are added to the samples. Finally, we describe a detailed bioinformatics approach to extract DNA methylation levels of the target regions from the sequencing data. Combining barcodes with indices enables a high level of multiplexing allowing to sequence multiple pooled samples in the same sequencing run. Therefore, this method is a robust, accurate, quantitative, and cheap approach for the readout of DNA methylation patterns at defined genomic regions.

Methylation of the Selected TP53 Introns in Advanced-Stage Ovarian Carcinomas.

Objective: Advanced-stage ovarian cancer (OC) is among the most fatal female genital tract neoplasms worldwide. Although different genetic mechanisms have been shown to be involved in ovarian carcinogenesis, the role of TP53 introns methylation is still unresolved. We performed methylation analysis of introns 1, 3, and 4 of the TP53 to identify patterns in primary stage III OCs, corresponding metastases, and healthy tissues. Methods: The study involved samples of paraffin-embedded tissues obtained from 80 patients with stage III OCs, who underwent surgery at the Department of Gynecology and Gynecologic Oncology of the Military Institute of Medicine in Warsaw, Poland. Altogether, 40 serous-type G2/3 OCs and 40 endometrioid-type G2/3 OCs were included. From the same patient, metastatic and normal tissues were simultaneously analyzed. As a control group, 80 tissue samples were collected from patients after bariatric operations. Human ovarian cancer A2780 cell line was also investigated. Total genomic DNA was isolated from paraffin-embedded tissue blocks and the methylation analysis was performed by bisulfite DNA conversion, DNA amplification with specific primers, cloning, and DNA sequencing. Results: All of the samples of intron 1 of TP53 were un-methylated in OCs, metastatic tissues, and in healthy tissues from the same patient. Also, no methylation of TP53 intron 1 was detected in cells from the human A2780 ovarian cancer cell line and in all samples from control group. In all samples, introns 3 and 4 of the TP53 were methylated in primary tumors, metastatic tissue, and in healthy tissue from the same patient, in human A2780 ovarian cell line, and in DNA samples from healthy patients. None of the clinicopatholocal features was related to the TP53 introns methylation status. Conclusions: Our data on TP53 introns methylation sheds new light on the mechanism of p53 activity for a better understanding of cancer biology. The study suggests the existence of an additional regulation rule of TP53 activity that involves demethylation-methylation mechanisms. Methylation at introns 3 and 4 may also overall help in protecting TP53 against damage by viral restrictases or viral DNA integration.

DNA methylation-based age estimation and quantification of the degradation levels of bisulfite-converted DNA

DNA methylation modifications are known to influence epigenetic phenomena and have been a focus of forensic science research for some time. Degraded DNA after bisulfite treatment is widely used in DNA methylation analysis. In this study, we analyzed methylation levels at 12 CpG sites of four selected genomic regions by pyrosequencing after bisulfite treatment. DNA was extracted from buccal swab samples collected from 102 Japanese individuals who were 21–77 years old. We also developed a simple method to quantify the degradation levels of bisulfite-converted DNA by real-time PCR, and evaluated the effect of DNA degradation on age estimation. We found that the methylation levels and chronological ages were highly correlated in the four selected regions, and the mean absolute deviation (MAD) between chronological and estimated ages was low at 3.88 years. These results indicated that pyrosequencing analysis at the 12 CpGs was useful for age estimation in the Japanese population. To develop a sensitive quantification method, we analyzed the amplification efficiency of short and long fragments from 10 regions by real-time PCR. The amplification efficiency was highest for CCDC102B, and the degradation levels of bisulfite-converted DNA for the 102 samples were categorized as moderately or heavily degraded. For the younger age groups (20–49 years), the MADs were lower for moderately degraded DNA than they were for heavily degraded DNA. This finding indicates that degradation levels affected the accuracy of age estimation in most of the samples; the exception was the samples from the 50–77 years age group.

The Role of the IGF2 Methylation Score in Diagnosing Adrenocortical Tumors with Unclear Malignant Potential-Feasibility of Formalin-Fixed Paraffin-Embedded Tissue.

The differentiation between benign and malignant adrenocortical tumors based on pathological assessment can be difficult. We present a series of 17 patients with unclear malignant tumors, of whom six had recurrent or metastatic disease. The assessment of the methylation pattern of insulin-like growth factor 2 (IGF2) regulatory regions in fresh frozen material has shown to be valuable in determining the malignancy of adrenocortical tumors, although this has not been elaborately tested in unclear malignant tumors. Since fresh frozen tissue was only available in six of the patients, we determined the feasibility of using formalin-fixed paraffin-embedded (FFPE) tissue for this method. We isolated DNA from FFPE tissue and matched the fresh frozen tissue of three patients with adrenocortical carcinoma. Methylation patterns of IGF2 regulatory regions were determined by pyrosequencing using different amounts of bisulfite-converted DNA (5 ng, 20 ng, 40 ng). Compared to fresh frozen tissue, FFPE tissue had a higher failure rate (fresh frozen 0%; FFPE 18.5%) and poor-to-moderate replicability (fresh frozen rho = 0.89-0.99, median variation 1.6%; FFPE rho = -0.09-0.85, median variation 7.7%). There was only a poor-to-moderate correlation between results from fresh frozen and FFPE tissue (rho = -0.28-0.70, median variation 13.2%). In conclusion, FFPE tissue is not suitable for determining the IGF2 methylation score in patients with an unclear malignant adrenocortical tumor using the currently used method. We, therefore, recommend fresh frozen storage of resection material for diagnostic and biobank purposes.

PD-1 Overexpression in Sézary Syndrome Is Epigenetically Regulated

PD-1 Overexpression in Sézary Syndrome Is Epigenetically Regulated

Mediation effects of DNA methylation and hydroxymethylation on birth outcomes after prenatal per- and polyfluoroalkyl substances (PFAS) exposure in the Michigan mother–infant Pairs cohort

BackgroundPer- and polyfluoroalkyl substances (PFAS) are chemicals that are resistant to degradation and ubiquitous in our environments. PFAS may impact the developing epigenome, but current human evidence is limited to assessments of total DNA methylation. We assessed associations between first trimester PFAS exposures with newborn DNA methylation, including 5-methylcytosine (5-mC) and 5-hydroxymethylcytosine (5-hmC). DNA methylation mediation of associations between PFAS and birth outcomes were explored in the Michigan Mother Infant Pairs cohort. Nine PFAS were measured in maternal first trimester blood. Seven were highly detected and included for analysis: PFHxS, PFOA, PFOS, PFNA, PFDA, PFUnDA, and MeFOSAA. Bisulfite-converted cord blood DNA (n = 141) and oxidative-bisulfite-converted cord blood (n = 70) were assayed on Illumina MethylationEPIC BeadChips to measure total DNA methylation (5-mC + 5-hmC) and 5-mC/5-hmC. Correcting for multiple comparisons, beta regressions were used to assess associations between levels of PFAS and total methylation, 5-mC, or 5-hmC. Nonlinear mediation analyses were used to assess the epigenetic meditation effect between PFAS and birth outcomes.ResultsPFAS was significantly associated with total methylation (q < 0.05: PFHxS—12 sites; PFOS—19 sites; PFOA—2 sites; PFNA—3 sites; PFDA—4 sites). In 72 female infants and 69 male infants, there were sex-specific associations between five PFAS and DNA methylation. 5-mC and 5-hmC were each significantly associated with thousands of sites for PFHxS, PFOS, PFNA, PFDA, PFUnDA, and MeFOSAA (q < 0.05). Clusters of 5-mC and 5-hmC sites were significant mediators between PFNA and PFUnDA and decreased gestational age (q < 0.05).ConclusionsThis study demonstrates the mediation role of specific types of DNA methylation on the relationship between PFAS exposure and birth outcomes. These results suggest that 5-mC and 5-hmC may be more sensitive to the developmental impacts of PFAS than total DNA methylation.