Defining Driver DNA Methylation Changes in Human Cancer

Pan-cancer analysis and single-cell analysis reveals FAM110B as a potential target for survival and immunotherapy

Background: FAM110B belongs to the family that has a 110 sequence similarity (FAM110) and is located in the centrosome and mitotic spindle. FAM110B has been linked to tumor cell growth in earlier research. Uncertainty exists regarding FAM110B's function within the tumor microenvironment is unclear as well as pan-cancer. Methods: In order to assess the variation in FAM110B expression within normal and pan-cancer tissues, we combined the TCGA and GTEx databases. The cBioPortal database and the GSCALite platform were used to examine the variation in genome and methylation alteration of FAM110B. Cox regression, Kaplan-Meier, and SangerBox were employed to examine the clinical features and prognosis of FAM110B and pan-cancer. The purpose of the correlational research was to investigate the associations within immunerelated genes, tumor mutation burden, microsatellite instability, immune-related genes, and immunological checkpoints and FAM110B expression. ESTIMATE, EPIC, QUANTISEQ, and MCPCOUNTER methods were used to calculate the interaction among FAM110B expression as well as the tumor immune microenvironment. The immunoinfiltration and function of FAM110B were analyzed by single-cell databases (TISCH and CancerSEA). Finally, we evaluated the sensitivity of FAM110B to small-molecule medications through GDSC and CTRP databases. Results: The transcription and protein expression of FAM110B varies significantly throughout cancer types, and this has predictive value for the prognosis of some tumors; including brain lower grade glioma (LGG), stomach adenocarcinoma (STAD), pancreatic adenocarcinoma (PAAD), etc. In the tumor microenvironment, the expression level of FAM110B was associated with immune cell infiltration, immune checkpoint immune regulatory genes, tumor mutational burden, and microsatellite fragility to a certain extent. Conclusion: This work investigates the possibility of utility of FAM110B as a marker to forecast pan-cancer immunotherapy response, providing a theoretical basis for cancer therapy.

DNA methylation biomarkers for predicting lymph node metastasis in colorectal cancer

Colorectal cancer is one of the most common cancers worldwide. Lymph node metastasis is an important marker of colorectal cancer progression and plays a key role in the evaluation of patient prognosis. Accurate preoperative assessment of lymph node metastasis is crucial for devising appropriate treatment plans. However, current clinical imaging methods have limitations in many aspects. Therefore, the discovery of a method for accurately predicting lymph node metastasis is crucial clinical decision-making. DNA methylation is a common epigenetic modification that can regulate gene expression, which also has an important impact on the development of colorectal cancer. It is considered to be a promising biomarker with good specificity and stability and has promising application in predicting lymph node metastasis in patients with colorectal cancer. This article reviews the characteristics and limitations of currently available methods for predicting lymph node metastasis in patients with colorectal cancer and discusses the role of DNA methylation as a biomarker.

SFRP4 protein expression is reduced in high grade astrocytomas which is not caused by the methylation of its promoter

Introduction

Epigenetics play a vital role in stratifying CNS tumors and gliomas. The importance of studying Secreted frizzled-related protein 4 (SFRP4) in gliomas is to improve diffuse glioma methylation profiling. Here we examined the methylation status of SFRP4 promoter and the level of its protein expression in diffuse gliomas WHO grades 2-4.

Methods

SFRP4 expression was detected by immunohistochemistry and evaluated semi-quantitatively. In the tumor hot-spot area, the intensity of protein expression in 200 cells was determined using ImageJ (National Institutes of Health, United States). The assessment of immunopositivity was based on the IRS score (Immunoreactivity Score). Promoter methylation was examined by methylation specific-PCR (MSP) in fifty-one diffuse glioma samples and appropriate controls. Isolated DNA was treated with bisulfite conversion and afterwards used for MSP. Public databases (cBioPortal, COSMIC and LOVD) were searched to corroborate the results.

Results and discussion

SFRP4 protein expression in glioblastomas was very weak or non-existent in 86.7% of samples, moderate in 13.3%, while strong expression was not observed. The increase in astrocytoma grade resulted in SFRP4 protein decrease (p = 0.008), indicating the loss of its antagonistic role in Wnt signaling. Promoter methylation of SFRP4 gene was found in 16.3% of cases. Astrocytomas grade 2 had significantly more methylated cases compared to grade 3 astrocytomas (p = 0.004) and glioblastomas (p < 0.001), which may indicate temporal niche of methylation in grade 2. Furthermore, the expression levels of SFRP4 were high in samples with methylated SFRP4 promoter and low or missing in unmethylated cases (Pearson's R = -0.413; p = 0.003). We also investigated the association of SFRP4 changes to key Wnt regulators GSK3β and DKK3 and established a positive correlation between methylations of SFRP4 and GSK3β (Pearson's R = 0.323; p = 0.03). Furthermore, SFRP4 expression was correlated to unmethylated DKK3 (Chi square = 7.254; p = 0.027) indication that Wnt signaling antagonist is associated to negative regulator's demethylation.

Conclusion

The study contributes to the recognition of the significance of epigenetic changes in diffuse glioma indicating that restoring SFRP4 protein holds potential as therapeutic avenue. Reduced expression of SFRP4 in glioblastomas, not following promoter methylation pattern, suggests another mechanism, possible global methylation, that turns off SFRP4 expression in higher grades.

Predictive value of peripheral blood leukocytes-based methylation of Long non-coding RNA MALAT1 and H19 in the chemotherapy effect and prognosis of gastric cancer

BACKGROUND

The predictive value of the methylation of Long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and H19 promoters in peripheral blood leukocytes as a non-invasive biomarker for the chemotherapy effect and prognosis gastric cancer (GC) is unclear.

METHODS

The DNA methylation of H19 and MALAT1 between chemotherapy-sensitive and non-sensitive groups and between groups with better and worse survival of GC was compared using regression analyses. Several predictive nomograms were constructed. The genetic alteration of MALAT1 and H19 and the association between gene expression and immune status in GC were also investigated using bioinformatics analysis.

RESULTS

Higher genetic methylations in peripheral blood were noticed in GC groups with poorer survival. The constructed nomograms presented strong predictive values for the chemotherapy effect and 3-year survival of disease-free survival, progression-free survival, and overall survival, with the area under the curve as 0.838, 0.838, 0.912, and 0.925, respectively. Significant correlations between MALAT1 or H19 expression and marker genes of immune checkpoints and immune pathways were noticed. The high infiltration of macrophages in H19-high and low infiltration of CD8+ T cells in MALAT1-high groups were associated with worse survival of GC.

CONCLUSIONS

MALAT1 and H19 have the potential to predict the chemotherapy response and clinical outcomes of GC.

A novel subtype based on driver methylation-transcription in lung adenocarcinoma

AIMS

To identify driver methylation genes and a novel subtype of lung adenocarcinoma (LUAD) by multi-omics and elucidate its molecular features and clinical significance.

METHODS

We collected LUAD patients from public databases, and identified driver methylation genes (DMGs) by MethSig and MethylMix algrothms. And novel driver methylation multi-omics subtypes were identified by similarity network fusion (SNF). Furthermore, the prognosis, tumor microenvironment (TME), molecular features and therapy efficiency among subtypes were comprehensively evaluated.

RESULTS

147 overlapped driver methylation were identified and validated. By integrating the mRNA expression and methylation of DMGs using SNF, four distinct patterns, termed as S1-S4, were characterized by differences in prognosis, biological features, and TME. The S2 subtype showed unfavorable prognosis. By comparing the characteristics of the DMGs subtypes with the traditional subtypes, S3 was concentrated in proximal-inflammatory (PI) subtype, and S4 was consisted of terminal respiratory unit (TRU) subtype and PI subtype. By analyzing TME and epithelial mesenchymal transition (EMT) features, increased immune infiltration and higher expression of immune checkpoint genes were found in S3 and S4. While S4 showed higher EMT score and expression of EMT associated genes, indicating S4 may not be as immunosensitive as the S3. Additionally, S3 had lower TIDE and higher IPS score, indicating its increased sensitivity to immunotherapy.

CONCLUSION

The driver methylation-related subtypes of LUAD demonstrate prognostic predictive ability that could help inform treatment response and provide complementary information to the existing subtypes.

Identification of methylation driver genes for predicting the prognosis of pancreatic cancer patients based on whole-genome DNA methylation sequencing technology

This study was based on the use of whole-genome DNA methylation sequencing technology to identify DNA methylation biomarkers in tumor tissue that can predict the prognosis of patients with pancreatic cancer (PCa). TCGA database was used to download PCa-related DNA methylation and transcriptome atlas data. Methylation driver genes (MDGs) were obtained using the MethylMix package. Candidate genes in the MDGs were screened for prognostic relevance to PCa patients by univariate Cox analysis, and a prognostic risk score model was constructed based on the key MDGs. ROC curve analysis was performed to assess the accuracy of the prognostic risk score model. The effects of PIK3C2B knockdown on malignant phenotypes of PCa cells were investigated in vitro. A total of 2737 differentially expressed genes were identified, with 649 upregulated and 2088 downregulated, using 178 PCa samples and 171 normal samples. MethylMix was employed to identify 71 methylation-driven genes (47 hypermethylated and 24 hypomethylated) from 185 TCGA PCa samples. Cox regression analyses identified eight key MDGs (LEF1, ZIC3, VAV3, TBC1D4, FABP4, MAP3K5, PIK3C2B, IGF1R) associated with prognosis in PCa. Seven of them were hypermethylated, while PIK3C2B was hypomethylated. A prognostic risk prediction model was constructed based on the eight key MDGs, which was found to accurately predict the prognosis of PCa patients. In addition, the malignant phenotypes of PANC-1 cells were decreased after the knockdown of PIK3C2B. Therefore, the prognostic risk prediction model based on the eight key MDGs could accurately predict the prognosis of PCa patients.

Mitochondrial ribosomal protein S24 is associated with immunosuppressive microenvironment and cold tumor in lung adenocarcinoma

Objective

MRPS24 (Mitochondrial Ribosomal Protein S24) belongs to the mitochondrial ribosomal protein family, which participates in the protein synthesis of the mitochondrion. However, the relationship of MRPS24 with lung adenocarcinoma (LUAD) remained unknown. We aimed to identify its immunological and functional mechanisms in LUAD.

Methods

The analysis of MRPS24 expression, clinical features, diagnosis, prognosis, function analysis, genetic alteration, copy number variations, methylation, and tumor microenvironment was investigated by the TCGA, UCSC Xena, GEO, HPA, GEPIA, cBioPortal, MethSurv, TIMER, TIMER2.0, and TISIDB databases.

Results

MRPS24 was found to be more abundant in LUAD tumor tissue than in normal tissue. High levels of MRPS24 expression were found to be an independent prognostic factor by multivariate analysis. Functional analysis revealed that MRPS24 expression was associated with the immune, cell cycle and methylation. MRPS24 methylation level was inversely linked with its expression (p < 0.001). Patients with low MRPS24 methylation had a worse prognosis than those with high methylation (p < 0.05). In addition, the result revealed that the MRPS24 expression was inversely linked to the immune cell infiltration in LUAD. Finally, the validations of the expression level, prognosis, and immune cell infiltration of MRPS24 were in accordance with our previous results.

Conclusions

This study systematically explored that MRPS24 expression was significantly correlated with prognosis, tumorigenesis, genetic alteration, copy number variations, methylation, and immune cell infiltration in LUAD. MRPS24 might be a potential immune-related biomarker in the development and treatment of LUAD, thereby acting as a promising predictor of immunotherapy response in LUAD.

Methylation in cornea and corneal diseases: a systematic review

Corneal diseases are among the primary causes of blindness and vision loss worldwide. However, the pathogenesis of corneal diseases remains elusive, and diagnostic and therapeutic tools are limited. Thus, identifying new targets for the diagnosis and treatment of corneal diseases has gained great interest. Methylation, a type of epigenetic modification, modulates various cellular processes at both nucleic acid and protein levels. Growing evidence shows that methylation is a key regulator in the pathogenesis of corneal diseases, including inflammation, fibrosis, and neovascularization, making it an attractive potential therapeutic target. In this review, we discuss the major alterations of methylation and demethylation at the DNA, RNA, and protein levels in corneal diseases and how these dynamics contribute to the pathogenesis of corneal diseases. Also, we provide insights into identifying potential biomarkers of methylation that may improve the diagnosis and treatment of corneal diseases.

Differential methylation of DNA promoter sequences in peripheral blood mononuclear cells as promising diagnostic biomarkers for colorectal cancer

OBJECTIVES

Previous reports have indicated that the methylation profile in peripheral blood mononuclear cells (PBMCs) in different genes and loci is altered in colorectal cancer (CRC). Regarding the high mortality rate and silent nature of CRC, screening and early detection can meaningfully reduce disease-related deaths. Therefore, for the first time, we aimed to evaluate the early non-invasive diagnosis of CRC via quantitative promoter methylation analysis of RUNX3 and RASSF1A genes in PBMCs.

MATERIALS AND METHODS

In the present study, we analyzed the methylation status of two important tumor suppressor genes including RUNX3 and RASSF1A in 70 CRC patients and 70 non-malignant subjects using methylation-quantification of endonuclease-resistant DNA (MethyQESD), and a bisulfite conversion-independent method.

RESULTS

RUNX3 was significantly hypermethylated in PBMCs of CRC patients compared to healthy controls (P < 0.001). By determining the efficient cutoff value, the sensitivity, and specificity of RUNX3 promoter methylation for CRC diagnosis reached 84.28% and 77.14%, respectively. The receiver operating characteristic (ROC) curve analyses demonstrated that RUNX3 promoter methylation has high accuracy (areas under the curve [AUC] = 0.840, P < 0.001) for discriminating CRC subjects from healthy individuals. Moreover, RUNX3 methylation levels in PBMCs progressively increased with the stage of the disease (P < 0.001). Although the amount of RASSF1A promoter methylation was not significantly different between CRC patients and controls as well as in different stages of the disease (P > 0.05).

CONCLUSION

Our findings confirmed that PBMCs are reliable sources of methylation analysis for CRC screening, and RUNX3 promoter methylation can be used as a promising biomarker for early diagnosis of CRC.

Differential DNA methylation landscape of miRNAs genes in mice liver fibrosis

BACKGROUND

Patients with chronic liver disease were found nearly all to have liver fibrosis, which is characterized by excess accumulation of extracellular matrix (ECM) proteins. While ECM accumulation can prevent liver infection and injury, it can destroy normal liver function and architecture. miRNA's own regulation was involved in DNA methylation change. The purpose of this study is to detect DNA methylation landscape of miRNAs genes in mice liver fibrosis tissues.

METHODS

Male mice (10-12 weeks) were injected CCl4 from abdominal cavity to induced liver fibrosis. 850 K BeadChips were used to examine DNA methylation change in whole genome. The methylation change of 16 CpG dinucleotides located in promoter regions of 4 miRNA genes were detected by bisulfite sequencing polymerase chain reaction (BSP) to verify chip data accuracy, and these 4 miRNA genes' expressions were detected by RT-qPCR methods.

RESULTS

There are 769 differential methylation sites (DMS) in total between fibrotic liver tissue and normal mice liver tissue, which were related with 148 different miRNA genes. Chips array data were confirmed by bisulfite sequencing polymerase chain reaction (R = 0.953; P < 0.01). GO analysis of the target genes of 2 miRNA revealed that protein binding, cytoplasm and chromatin binding activity were commonly enriched; KEGG pathway enrichment analysis displayed that TGF-beta signaling pathway was commonly enriched.

CONCLUSION

The DNA of 148 miRNA genes was found to have methylation change in liver fibrosis tissue. These discoveries in miRNA genes are beneficial to future miRNA function research in liver fibrosis.

Epigenetic modifications in solid tumor metastasis in people of African ancestry

This review focuses on the critical role of epigenetic modifications in solid tumor metastasis, particularly in people of African ancestry. Epigenetic alterations, such as DNA methylation, histone modifications, alterations in non-coding RNAs, and mRNA methylation, significantly influence gene expression, contributing to cancer development and progression. Despite the primary focus on populations of European, American, and Asian descent in most cancer research, this work emphasizes the importance of studying the unique genetic and epigenetic landscapes of African populations for a more inclusive approach in understanding and treating cancer. Insights from this review have the potential to pave the way for the development of effective, tailored treatments, and provide a richer resource for understanding cancer progression and metastasis. Specific focus was placed on the role of DNA methylation, histone modifications, non-coding RNAs, and mRNA methylation in solid tumor metastasis, including how these modifications contribute to the regulation of tumor suppressor genes and oncogenes, influence cellular pathways and signaling, and interact with the immune system. Moreover, this review elaborates on the development of epigenetic-targeted therapeutic strategies and the current advances in this field, highlighting the promising applications of these therapies in improving outcomes for African ancestry populations disproportionately affected by certain types of cancer. Nevertheless, this work acknowledges the challenges that lie ahead, particularly the under-representation of African populations in cancer genomic and epigenomic studies and the technical complications associated with detecting subtle epigenetic modifications. Emphasis is placed on the necessity for more inclusive research practices, the development of more robust and sensitive methods for detecting and interpreting epigenetic changes, and the understanding of the interplay between genetic and epigenetic variations. The review concludes with an optimistic outlook on the future of epigenetic research in People of African ancestry, urging the concerted efforts of researchers, clinicians, funding agencies, and policymakers to extend the benefits of this research to all populations.

An assessment of alterations to human sperm methylation patterns in coronavirus disease 2019 infected and healthy control males

OBJECTIVE

To determine whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection affects male reproductive health, considering the many potential factors that contribute to declines in male fertility on a semiglobal scale.

DESIGN

In total, 64 human semen samples-32 treatment and 32 control-were laboratory processed and bioinformatically analyzed to assess differences in DNA methylation patterns. Implementing multiple bioinformatic tools, the analyses conducted will elicit between-group differences with respect to epigenetic age, epigenetic instability, semiglobal, and regional methylation, in addition to methylation patterns as a function of time since infection.

SETTING

University hospital.

PATIENTS

The study cohort of 64 individuals was drawn from a larger population of 94 volunteer participants recruited at the Human Reproduction Center at the Clinical Hospital of the Ribeirao Preto Medical School-University of São Paulo between June 2021 and January 2022 as well as in accordance with the ethical guidelines established by the Declaration of Helsinki.

INTERVENTION

Exposure to SARS-CoV-2.

MAIN OUTCOME MEASURE(S)

Effects on male reproductive health were reported as differences in DNA methylation measured using an array. Mean β values at key regulatory loci for human spermatocytes were analyzed and compared between groups. Further analysis of β values using epigenetic age, instability, semiglobal, and regional methylation tools provided an analysis with substantial breadth and depth.

RESULTS

In all analyses, there were no differences between groups. Considering these results, it can be inferred that infection with SARS-CoV-2 does not alter the epigenome of human spermatocytes in significant and/or persistent ways. Tangentially, these data also suggest that human male reproductive health is minimally altered by the virus, or that it is altered in a way that is independent of epigenetic programming.

CONCLUSION

Infection with SARS-CoV-2 has been reportedly associated with alterations in male fertility. This study asserts that such alterations do not have an epigenetic basis but are likely a result of concomitant symptomatology, i.e., fever and inflammation. Across the multiple bioinformatic analyses conducted, the results of this test did not detect any differences in DNA methylation patterns between coronavirus disease 2019 and noncoronavirus disease semen donor groups.

Role of Epigenetics for the Efficacy of Cisplatin

The clinical utility of the chemotherapeutic agent cisplatin is restricted by cancer drug resistance, which is either intrinsic to the tumor or acquired during therapy. Epigenetics is increasingly recognized as a factor contributing to cisplatin resistance and hence influences drug efficacy and clinical outcomes. In particular, epigenetics regulates gene expression without changing the DNA sequence. Common types of epigenetic modifications linked to chemoresistance are DNA methylation, histone modification, and non-coding RNAs. This review provides an overview of the current findings of various epigenetic modifications related to cisplatin efficacy in cell lines in vitro and in clinical tumor samples. Furthermore, it discusses whether epigenetic alterations might be used as predictors of the platinum agent response in order to prevent avoidable side effects in patients with resistant malignancies. In addition, epigenetic targeting therapies are described as a possible strategy to render cancer cells more susceptible to platinum drugs.

Chromothripsis is rare in IDH-mutant gliomas compared to IDH-wild-type glioblastomas whereas whole-genome duplication is equally frequent in both tumor types

Background

Adult-type diffuse gliomas comprise IDH (isocitrate dehydrogenase)-mutant astrocytomas, IDH-mutant 1p/19q-codeleted oligodendrogliomas (ODG), and IDH-wild-type glioblastomas (GBM). GBM displays genome instability, which may result from 2 genetic events leading to massive chromosome alterations: Chromothripsis (CT) and whole-genome duplication (WGD). These events are scarcely described in IDH-mutant gliomas. The better prognosis of the latter may be related to their genome stability compared to GBM.

Methods

Pangenomic profiles of 297 adult diffuse gliomas were analyzed at initial diagnosis using SNP arrays, including 192 GBM and 105 IDH-mutant gliomas (61 astrocytomas and 44 ODG). Tumor ploidy was assessed with Genome Alteration Print and CT events with CTLPScanner and through manual screening. Survival data were compared using the Kaplan-Meier method.

Results

At initial diagnosis, 37 GBM (18.7%) displayed CT versus 5 IDH-mutant gliomas (4.7%; P = .0008), the latter were all high-grade (grade 3 or 4) astrocytomas. WGD was detected at initial diagnosis in 18 GBM (9.3%) and 9 IDH-mutant gliomas (5 astrocytomas and 4 oligodendrogliomas, either low- or high-grade; 8.5%). Neither CT nor WGD was associated with overall survival in GBM or in IDH-mutant gliomas.

Conclusions

CT is less frequent in IDH-mutant gliomas compared to GBM. The absence of CT in ODG and grade 2 astrocytomas might, in part, explain their genome stability and better prognosis, while CT might underlie aggressive biological behavior in some high-grade astrocytomas. WGD is a rare and early event occurring equally in IDH-mutant gliomas and GBM.

JAK1 Is a Novel Target of Tumor- and Invasion-Suppressive microRNA 494-5p in Colorectal Cancer

MiR-494-5p expression has been suggested to be associated with colorectal cancer (CRC) and its metastases in our previous studies. However, functional investigations on the molecule-mediating actions of this miR in CRC are lacking. In silico analysis in the present study revealed a putative binding sequence within the 3'UTR of JAK1. Overexpression of miR-494-5p in cultured CRC significantly reduced the luciferase activity of a reporter plasmid containing the wild-type JAK1-3'UTR, which was abolished by seed sequence mutation. Furthermore, the overexpression of miR-494-5p in CRC cell lines led to a significant reduction in JAK1 expression, proliferation, in vitro migration, and invasion. These effects were abolished by co-transfection with a specific double-stranded RNA that inhibits endogenous miR-494-5p. Moreover, IL-4-induced migration, invasion, and phosphorylation of JAK1, STAT6, and AKT proteins were reduced after an overexpression of this miR, suggesting that this miR affects one of the most essential pathways in CRC. A Kaplan-Meier plotter analysis revealed that patients with high JAK1 expression show reduced survival. Together, these data suggest that miR-494-5p physically inhibits the expression of JAK1 at the translational level as well as in migration and invasion, supporting the hypothesis of miR-494-5p as an early tumor suppressor and inhibitor of early steps of metastasis in CRC.

A comprehensive characterisation of phaeochromocytoma and paraganglioma tumours through histone protein profiling, DNA methylation and transcriptomic analysis genome wide

BACKGROUND

Phaeochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumours. Pathogenic variants have been identified in more than 15 susceptibility genes; associated tumours are grouped into three Clusters, reinforced by their transcriptional profiles. Cluster 1A PPGLs have pathogenic variants affecting enzymes of the tricarboxylic acid cycle, including succinate dehydrogenase. Within inherited PPGLs, these are the most common. PPGL tumours are known to undergo epigenetic reprograming, and here, we report on global histone post-translational modifications and DNA methylation levels, alongside clinical phenotypes.

RESULTS

Out of the 25 histone post-translational modifications examined, Cluster 1A PPGLs were distinguished from other tumours by a decrease in hyper-acetylated peptides and an increase in H3K4me2. DNA methylation was compared between tumours from individuals who developed metastatic disease versus those that did not. The majority of differentially methylated sites identified tended to be completely methylated or unmethylated in non-metastatic tumours, with low inter-sample variance. Metastatic tumours by contrast consistently had an intermediate DNA methylation state, including the ephrin receptor EPHA4 and its ligand EFNA3. Gene expression analyses performed to identify genes involved in metastatic tumour behaviour pin-pointed a number of genes previously described as mis-regulated in Cluster 1A tumours, as well as highlighting the tumour suppressor RGS22 and the pituitary tumour-transforming gene PTTG1.

CONCLUSIONS

Combined transcriptomic and DNA methylation analyses revealed aberrant pathways, including ones that could be implicated in metastatic phenotypes and, for the first time, we report a decrease in hyper-acetylated histone marks in Cluster 1 PPGLs.

Diagnostic value of FOXF1 gene promoter-methylated DNA in the plasma samples of patients with colorectal cancer

BACKGROUND

Epigenetic modifications such as DNA methylation in the CpG islands of genes occur at a high rate. In this study, we measured the methylation level of the promoter region of the FOXF1 gene as a new blood biomarker for the detection of colorectal cancer in the early stages.

METHODS

The methylation level of the promoter region of the FOXF1 gene was measured in the plasma samples of 50 colorectal cancer patients and 50 normal individuals. DNA was extracted after exposure to sodium bisulfite by the MethyLight polymerase chain reaction (PCR) method. The percentage of promoter region was measured in all samples, and statistical analysis was done using SPSS v24 software.

RESULTS

The average promoter region between the plasma samples of colorectal cancer patients and healthy individuals had a significant difference (P < 0.001). The average promoter region of the FOXF1 gene in tumor plasma samples was 7.1 and in the control samples was 0.48. The sensitivity and specificity of the sample plasma levels were 78% and 89.5%, respectively.

CONCLUSION

The promoter region value of the FOXF1 gene in plasma samples using the MethyLight PCR method had high sensitivity and specificity as a non-invasive method for colorectal cancer diagnosis. This research is the first report that has been presented regarding the investigation of FOXF1 gene methylation in plasma samples in colorectal cancer. Therefore, it is necessary to conduct more studies with larger size samples to evaluate the efficiency of the gene under investigation.

Epigenetic regulation in lung cancer

Lung cancer is indeed a major cause of cancer-related deaths worldwide. The development of tumors involves a complex interplay of genetic, epigenetic, and environmental factors. Epigenetic mechanisms, including DNA methylation (DNAm), histone modifications, and microRNA expression, play a crucial role in this process. Changes in DNAm patterns can lead to the silencing of important genes involved in cellular functions, contributing to the development and progression of lung cancer. MicroRNAs and exosomes have also emerged as reliable biomarkers for lung cancer. They can provide valuable information about early diagnosis and treatment assessment. In particular, abnormal hypermethylation of gene promoters and its effects on tumorigenesis, as well as its roles in the Wnt signaling pathway, have been extensively studied. Epigenetic drugs have shown promise in the treatment of lung cancer. These drugs target the aberrant epigenetic modifications that are involved in the development and progression of the disease. Several factors have been identified as drug targets in non-small cell lung cancer. Recently, combination therapy has been discussed as a successful strategy for overcoming drug resistance. Overall, understanding the role of epigenetic mechanisms and their targeting through drugs is an important area of research in lung cancer treatment.

Unveiling the genetic and epigenetic landscape of colorectal cancer: new insights into pathogenic pathways

Colorectal cancer (CRC) is a complex disease characterized by genetic and epigenetic alterations, playing a crucial role in its development and progression. This review aims to provide insights into the emerging landscape of these alterations in CRC pathogenesis to develop effective diagnostic tools and targeted therapies. Genetic alterations in signaling pathways such as Wnt/β-catenin, and PI3K/Akt/mTOR are pivotal in CRC development. Genetic profiling has identified distinct molecular subtypes, enabling personalized treatment strategies. Epigenetic modifications, including DNA methylation and histone modifications, also contribute to CRC pathogenesis by influencing critical cellular processes through gene silencing or activation. Non-coding RNAs have emerged as essential players in epigenetic regulation and CRC progression. Recent research highlights the interplay between genetic and epigenetic alterations in CRC. Genetic mutations can affect epigenetic modifications, leading to dysregulated gene expression and signaling cascades. Conversely, epigenetic changes can modulate genetic expression, amplifying or dampening the effects of genetic alterations. Advancements in understanding pathogenic pathways have potential clinical applications. Identifying genetic and epigenetic markers as diagnostic and prognostic biomarkers promises more accurate risk assessment and early detection. Challenges remain, including validating biomarkers and developing robust therapeutic strategies through extensive research and clinical trials. The dynamic nature of genetic and epigenetic alterations necessitates a comprehensive understanding of their temporal and spatial patterns during CRC progression. In conclusion, the genetic and epigenetic landscape of CRC is increasingly being unraveled, providing valuable insights into its pathogenesis. Integrating genetic and epigenetic knowledge holds great potential for improving diagnostics, prognostics, and personalized therapies in CRC. Continued research efforts are vital to translate these findings into clinical practice, ultimately improving patient outcomes.

Cuproptosis-related gene SLC31A1: prognosis values and potential biological functions in cancer

Cuproptosis is a unique type of cell death that may influence tumour formation by targeting lipoylated tricarboxylic acid cycle proteins. Solute carrier family 31 member 1 (SLC31A1), an important copper transporter, influences dietary copper absorption in the cell membrane. However, various SLC31A1 properties in pan-cancer profiles remain unknown. This study investigated the role of SLC31A1 in human malignancies and analysed its prognostic value. Raw data were obtained from The Cancer Genome Atlas database and processed using numerous internet databases, including UALCAN, GEPIA, cBioPortal, TIMER2.0, and Human Protein Atlas. SLC31A1 expression was found to be elevated in cervical, endometrial, and breast cancers compared to that in normal tissues, but reduced in clear cell renal cell carcinoma, liver hepatocellular carcinoma, and lung adenocarcinoma. Furthermore, SLC31A1 expression was strongly associated with overall survival and disease-free survival in several cancers. SLC31A1 gene mutations and methylations were identified in 33 cancers. SLC31A1 expression was positively correlated with immune cells in immune infiltration data. Single-cell sequencing revealed that SLC31A1 may play key roles in DNA repair, DNA damage, and proliferation. These findings may lead to better understanding of SLC31A1 in pan-cancer profiles and suggest that SLC31A1 could be a viable predictive biomarker, particularly in gynaecological cancers.

Targeting the epigenome of cancer stem cells in pediatric nervous system tumors

Medulloblastoma, neuroblastoma, and pediatric glioma account for almost 30% of all cases of pediatric cancers. Recent evidence indicates that pediatric nervous system tumors originate from stem or progenitor cells and present a subpopulation of cells with highly tumorigenic and stem cell-like features. These cancer stem cells play a role in initiation, progression, and resistance to treatment of pediatric nervous system tumors. Histone modification, DNA methylation, chromatin remodeling, and microRNA regulation display a range of regulatory activities involved in cancer origin and progression, and cellular identity, especially those associated with stem cell features, such as self-renewal and pluripotent differentiation potential. Here, we review the contribution of different epigenetic mechanisms in pediatric nervous system tumor cancer stem cells. The choice between a differentiated and undifferentiated state can be modulated by alterations in the epigenome through the regulation of stemness genes such as CD133, SOX2, and BMI1 and the activation neuronal of differentiation markers, RBFOX3, GFAP, and S100B. Additionally, we highlighted the stage of development of epigenetic drugs and the clinical benefits and efficacy of epigenetic modulators in pediatric nervous system tumors.

Cell-free DNA approaches for cancer early detection and interception

Rapid advancements in the area of early cancer detection have brought us closer to achieving the goals of finding cancer early enough to treat or cure it, while avoiding harms of overdiagnosis. We evaluate progress in the development of early cancer detection tests in the context of the current principles for cancer screening. We review cell-free DNA (cfDNA)-based approaches using mutations, methylation, or fragmentomes for early cancer detection. Lastly, we discuss the challenges in demonstrating clinical utility of these tests before integration into routine clinical care.

DSTN Hypomethylation Promotes Radiotherapy Resistance of Rectal Cancer by Activating the Wnt/β-Catenin Signaling Pathway

PURPOSE

Although surgical resection combined with neoadjuvant radiation therapy can reduce the local recurrence rate of rectal cancer, not all patients benefit from neoadjuvant radiation therapy. Therefore, screening for patients with rectal cancer who are sensitive or resistant to radiation therapy has great clinical significance.

METHODS AND MATERIALS

Patients with rectal cancer were selected according to postoperative tumor regression grade, and tumor samples were taken for detection. Differential genes between radiation-resistant and radiation-sensitive tissues were screened and validated by Illumina Infinium MethylationEPIC BeadChip, proteomics, Agena MassARRAY methylation, reverse transcription quantitative real-time polymerase chain reaction, and immunohistochemistry. In vitro and in vivo functional experiments verified the role of DSTN. Protein coimmunoprecipitation, western blot, and immunofluorescence were used to investigate the mechanisms of DSTN-related radiation resistance.

RESULTS

DSTN was found to be highly expressed (P < .05) and hypomethylated (P < .01) in rectal cancer tissues resistant to neoadjuvant radiation therapy. Follow-up data confirmed that patients with high expression of DSTN in neoadjuvant radiation therapy-resistant rectal cancer tissues had shorter disease-free survival (P < .05). DSTN expression increased after methyltransferase inhibitor inhibition of DNA methylation in colorectal cancer cells (P < .05). In vitro and in vivo experiments showed that knockdown of DSTN promoted the sensitivity of colorectal cancer cells to radiation therapy, and overexpression of DSTN promoted the resistance of colorectal cancer cells to radiation (P < .05). The Wnt/β-catenin signaling pathway was activated in colorectal cancer cells overexpressing DSTN. β-catenin was highly expressed in radiation therapy-resistant tissues, and there was a linear correlation between the expression of DSTN and β-catenin (P < .0001). Further studies showed that DSTN can bind to β-catenin and increase its stability.

CONCLUSIONS

The degree of DNA methylation and the expression level of DSTN can be used as biomarkers to predict the sensitivity of neoadjuvant radiation therapy for rectal cancer. DSTN and β-catenin are also expected to become a reference for the selection of neoadjuvant radiation therapy.

Analytical and therapeutic profiles of DNA methylation alterations in cancer; an overview of changes in chromatin arrangement and alterations in histone surfaces

DNA methylation is the most important epigenetic element that activates the inhibition of gene transcription and is included in the pathogenesis of all types of malignancies. Remarkably, the effectors of DNA methylation are DNMTs (DNA methyltransferases) that catalyze de novo or keep methylation of hemimethylated DNA after the DNA replication process. DNA methylation structures in cancer are altered, with three procedures by which DNA methylation helps cancer development which are including direct mutagenesis, hypomethylation of the cancer genome, and also focal hypermethylation of the promoters of TSGs (tumor suppressor genes). Conspicuously, DNA methylation, nucleosome remodeling, RNA-mediated targeting, and histone modification balance modulate many biological activities that are essential and indispensable to the genesis of cancer and also can impact many epigenetic changes including DNA methylation and histone modifications as well as adjusting of non-coding miRNAs expression in prevention and treatment of many cancers. Epigenetics points to heritable modifications in gene expression that do not comprise alterations in the DNA sequence. The nucleosome is the basic unit of chromatin, consisting of 147 base pairs (bp) of DNA bound around a histone octamer comprised of one H3/H4 tetramer and two H2A/H2B dimers. DNA methylation is preferentially distributed over nucleosome regions and is less increased over flanking nucleosome-depleted DNA, implying a connection between nucleosome positioning and DNA methylation. In carcinogenesis, aberrations in the epigenome may also include in the progression of drug resistance. In this report, we report the rudimentary notes behind these epigenetic signaling pathways and emphasize the proofs recommending that their misregulation can conclude in cancer. These findings in conjunction with the promising preclinical and clinical consequences observed with epigenetic drugs against chromatin regulators, confirm the important role of epigenetics in cancer therapy.

Precision medicine in gastroenteropancreatic neuroendocrine neoplasms: Where are we in 2023?

Precision medicine describes a target-related approach to tailoring diagnosis and treatment of the individual patient. While this personalized approach is revoluzionizing many areas of oncology, it is quite late in the field of gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs), in which there are few molecular alterations to be therapeutically targeted. We critically reviewed the current evidence about precision medicine in GEP NENs, focusing on potential clinically relevant actionable targets for GEP NENs, such as the mTOR pathway, MGMT, hypoxia markers, RET, DLL-3, and some general agnostic targets. We analysed the main investigational approaches with solid and liquid biopsies. Furthermore, we reviewed a model of precision medicine more specific for NENs that is the theragnostic use of radionuclides. Overall, currently no true predictive factors for therapy have been validated so far in GEP NENs, and the personalized approach is based more on clinical thinking within a NEN-dedicated multidisciplinary team. However, there is a robust background to suppose that precision medicine, with the theragnostic model will yield new insights in this context soon.

Advances on Liquid Biopsy Analysis for Glioma Diagnosis

Gliomas comprise the most frequent primary central nervous system (CNS) tumors, characterized by remarkable genetic and epigenetic heterogeneity, difficulty in monitoring, and increased relapse and mortality rates. Tissue biopsy is an established method of tumor cell collection and analysis that enables diagnosis, classification of different tumor types, and prediction of prognosis upon confirmation of tumor's location for surgical removal. However, it is an invasive and often challenging procedure that cannot be used for frequent patient screening, detection of mutations, disease monitoring, or resistance to therapy. To this end, the minimally invasive procedure of liquid biopsy has emerged, allowing effortless tumor sampling and enabling continuous monitoring. It is considered a novel preferable way to obtain faster data on potential tumor risk, personalized diagnosis, prognosis, and recurrence evaluation. The purpose of this review is to describe the advances on liquid biopsy for glioma diagnosis and management, indicating several biomarkers that can be utilized to analyze tumor characteristics, such as cell-free DNA (cfDNA), cell-free RNA (cfRNA), circulating proteins, circulating tumor cells (CTCs), and exosomes. It further addresses the benefit of combining liquid biopsy with radiogenomics to facilitate early and accurate diagnoses, enable precise prognostic assessments, and facilitate real-time disease monitoring, aiming towards more optimal treatment decisions.

The Role of Methylation of a Group of microRNA Genes in the Pathogenesis of Metastatic Renal Cell Carcinoma

The role of methylation of 9 miRNA genes in the pathogenesis of metastatic clear cell renal cell carcinoma was determined by quantitative methylation-specific PCR (MS-PCR). For 5 genes (MIR125B-1, MIR137, MIR193A, MIR34B/C, and MIR375), a significant correlation of high methylation level with late (III-IV) stages, large size (T3+T4) of the tumor, and metastasis to lymph nodes and/or distant organs was revealed. For another group of genes (MIR125B-1, MIR1258, MIR193A, MIR34B/C, and MIR375), a statistically significant correlation of high methylation level with loss of differentiation in the tumor (G3-G4) was found, and the opposite pattern was found for MIR203A. A total of 7 microRNA genes (MIR125B-1, MIR1258, MIR137, MIR193A, MIR203A, MIR34B/C, and MIR375) were identified, the methylation of which is associated with the progression of metastatic clear cell renal cell carcinoma. For 6 of them (except MIR34B/C) these data were obtained for the first time. Thus, new factors of the development and progression of clear cell renal cell carcinoma were identified as potential biomarkers for the early diagnosis and prognosis of metastatic clear cell renal cell carcinoma.

Promoter Methylation-Regulated Differentially Expressed Genes in Breast Cancer

Background

Breast cancer is one of the most common malignancies among women. Recent studies revealed that differentially methylated regions (DMRs) are implicated in regulating gene expression. The goal of this research was to determine which genes and pathways are dysregulated in breast cancer when their promoters are methylated in an abnormal way, leading to differential expression. Whole-genome bisulfite sequencing was applied to analyze DMRs for eight peripheral blood samples collected from five Saudi females diagnosed with stages I and II of breast cancer aligned with three normal females. Three of those patients and three normal samples were used to determine differentially expressed genes (DEG) using Illumina platform NovaSeq PE150.

Results

Based on ontology (GO) and KEGG pathways, the analysis indicated that DMGs and DEG are closely related to associated processes, such as ubiquitin-protein transferase activity, ubiquitin-mediated proteolysis, and oxidative phosphorylation. The findings indicated a potentially significant association between global hypomethylation and breast cancer in Saudi patients. Our results revealed 81 differentially promoter-methylated and expressed genes. The most significant differentially methylated and expressed genes found in gene ontology (GO) are pumilio RNA binding family member 1 (PUM1) and zinc finger AN1-type containing 2B (ZFAND2B) also known as (AIRAPL).

Conclusion

The essential outcomes of this study suggested that aberrant hypermethylation at crucial genes that have significant parts in the molecular pathways of breast cancer could be used as a potential prognostic biomarker for breast cancer.

Promotor methylation in ocular surface squamous neoplasia development: epigenetics implications in molecular diagnosis

INTRODUCTION

Cancer is heavily influenced by epigenetic mechanisms that include DNA methylation, histone modifications, and non-coding RNA. A considerable proportion of human malignancies are believed to be associated with global DNA hypomethylation, with localized hypermethylation at promoters of certain genes.

AREA COVERED

The present review aims to emphasize on recent investigations on the epigenetic landscape of ocular surface squamous neoplasia, that could be targeted/explored using novel approaches such as personalized medicine.

EXPERT OPINION

While the former is thought to contribute to genomic instability, promoter-specific hypermethylation might facilitate tumorigenesis by silencing tumor suppressor genes. Ocular surface squamous neoplasia, the most prevalent type of ocular surface malignancy, is suggested to be affected by epigenetic mechanisms, as well. Although the exact role of epigenetics in ocular surface squamous neoplasia has mostly been unexplored, recent findings have greatly contributed to our understanding regarding this pathology of the eye.

Hypomethylation of Long Interspersed Nucleotide Elements and Aldehyde Dehydrogenase in Patients of Alcohol Use Disorder with Cirrhosis

Alcohol use disorder (AUD) and cirrhosis are key outcomes of excessive alcohol use, and a genetic influence in these outcomes is increasingly recognized. While 80-90% of heavy alcohol users show evidence of fatty liver, only 10-20% progress to cirrhosis. There is currently no clear understanding of the causes of this difference in progression. The aim of this study is to evaluate genetics and epigenetics at the aldehyde dehydrogenase (ALDH2) locus in patients with AUD and liver complications. Study participants were inpatients from the clinical services of Gastroenterology and Psychiatry at St. John's Medical College Hospital (SJMCH) and the National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India. Men diagnosed as having AUD with cirrhosis (AUDC+ve, N = 136) and AUD without cirrhosis (AUDC-ve, N = 107) were assessed. FibroScan/sonographic evidence was used to rule out fibrosis in the AUDC-ve group. Genomic DNA was used for genotyping at the ALDH2 (rs2238151) locus. A subset of 89 samples was used for DNA methylation (AUDC+ve, N = 44; and AUDC-ve, N = 45) analysis at long interspersed nucleotide element 1 (LINE-1) and ALDH2 cytosine-phosphate-guanine (CpG) loci by pyrosequencing. ALDH2 DNA methylation was significantly lower in the AUDC+ve group compared with the AUDC-ve group (p < 0.001). Lower methylation was associated with a risk allele (T) of the ALDH2 locus (rs2238151) (p = 0.01). Global (LINE-1) DNA methylation levels were also significantly lower in the AUDC+ve group compared with the AUDC-ve group (p = 0.01). Compromised global methylation (LINE-1) and hypomethylation at the ALDH2 gene was observed in patients with cirrhosis compared with those without cirrhosis. DNA methylation could be explored as a biomarker for cirrhosis and liver complications.

Analysis of the Mutational Landscape of Osteosarcomas Identifies Genes Related to Metastasis and Prognosis and Disrupted Biological Pathways of Immune Response and Bone Development

Osteosarcoma (OS) is the most prevalent type of bone tumor, but slow progress has been achieved in disentangling the full set of genomic events involved in its initiation and progression. We assessed by NGS the mutational spectrum of 28 primary OSs from Brazilian patients, and identified 445 potentially deleterious SNVs/indels and 1176 copy number alterations (CNAs). TP53 was the most recurrently mutated gene, with an overall rate of ~60%, considering SNVs/indels and CNAs. The most frequent CNAs (~60%) were gains at 1q21.2q21.3, 6p21.1, and 8q13.3q24.22, and losses at 10q26 and 13q14.3q21.1. Seven cases presented CNA patterns reminiscent of complex events (chromothripsis and chromoanasynthesis). Putative RB1 and TP53 germline variants were found in five samples associated with metastasis at diagnosis along with complex genomic patterns of CNAs. PTPRQ, KNL1, ZFHX4, and DMD alterations were prevalent in metastatic or deceased patients, being potentially indicative of poor prognosis. TNFRSF11B, involved in skeletal system development and maintenance, emerged as a candidate for osteosarcomagenesis due to its biological function and a high frequency of copy number gains. A protein-protein network enrichment highlighted biological pathways involved in immunity and bone development. Our findings reinforced the high genomic OS instability and heterogeneity, and led to the identification of novel disrupted genes deserving further evaluation as biomarkers due to their association with poor outcomes.

The interactions between DNA methylation machinery and long non-coding RNAs in tumor progression and drug resistance

DNA methylation is one of the main epigenetic mechanisms in cancer development and progression. Aberrant DNA methylation of CpG islands within promoter regions contributes to the dysregulation of various tumor suppressors and oncogenes; this leads to the appearance of malignant features, including rapid proliferation, metastasis, stemness, and drug resistance. The discovery of two important protein families, DNA methyltransferases (DNMTs) and Ten-eleven translocation (TET) dioxygenases, respectively, which are responsible for deregulated transcription of genes that play pivotal roles in tumorigenesis, led to further understanding of DNA methylation-related pathways. But how these enzymes can target specific genes in different malignancies; recent studies have highlighted the considerable role of Long Non-coding RNAs (LncRNAs). LncRNAs recruit these enzymes to promoter regions of genes and mediate their functions, showing great potential as therapeutic agents targeting the epigenetic regulation of various genes. Considering the importance of combining the current treatment methods, especially chemotherapies, with DNA methylation inhibitors in improving patients' outcomes, this review aimed to summarize the recent findings about the interaction between DNA methylation machinery and LncRNAs in regulating genes involved in tumorigenesis and drug resistance. So, these studies could provide insights toward developing novel strategies for cancer-targeted therapy.

The Mechanism of DNA Methylation and miRNA in Breast Cancer

Breast cancer is the most prevalent cancer in the world. Currently, the main treatments for breast cancer are radiotherapy, chemotherapy, targeted therapy and surgery. The treatment measures for breast cancer depend on the molecular subtype. Thus, the exploration of the underlying molecular mechanisms and therapeutic targets for breast cancer remains a hotspot in research. In breast cancer, a high level of expression of DNMTs is highly correlated with poor prognosis, that is, the abnormal methylation of tumor suppressor genes usually promotes tumorigenesis and progression. MiRNAs, as non-coding RNAs, have been identified to play key roles in breast cancer. The aberrant methylation of miRNAs could lead to drug resistance during the aforementioned treatment. Therefore, the regulation of miRNA methylation might serve as a therapeutic target in breast cancer. In this paper, we reviewed studies on the regulatory mechanisms of miRNA and DNA methylation in breast cancer from the last decade, focusing on the promoter region of tumor suppressor miRNAs methylated by DNMTs and the highly expressed oncogenic miRNAs inhibited by DNMTs or activating TETs.

Histone Demethylase Modulation: Epigenetic Strategy to Combat Cancer Progression

Epigenetic modifications are heritable, reversible changes in histones or the DNA that control gene functions, being exogenous to the genomic sequence itself. Human diseases, particularly cancer, are frequently connected to epigenetic dysregulations. One of them is histone methylation, which is a dynamically reversible and synchronously regulated process that orchestrates the three-dimensional epigenome, nuclear processes of transcription, DNA repair, cell cycle, and epigenetic functions, by adding or removing methylation groups to histones. Over the past few years, reversible histone methylation has become recognized as a crucial regulatory mechanism for the epigenome. With the development of numerous medications that target epigenetic regulators, epigenome-targeted therapy has been used in the treatment of malignancies and has shown meaningful therapeutic potential in preclinical and clinical trials. The present review focuses on the recent advances in our knowledge on the role of histone demethylases in tumor development and modulation, in emphasizing molecular mechanisms that control cancer cell progression. Finally, we emphasize current developments in the advent of new molecular inhibitors that target histone demethylases to regulate cancer progression.

Pan-cancer analysis revealed H3K4me1 at bivalent promoters premarks DNA hypermethylation during tumor development and identified the regulatory role of DNA methylation in relation to histone modifications

BACKGROUND

DNA hypermethylation at promoter CpG islands (CGIs) is a hallmark of cancers and could lead to dysregulation of gene expression in the development of cancers, however, its dynamics and regulatory mechanisms remain elusive. Bivalent genes, that direct development and differentiation of stem cells, are found to be frequent targets of hypermethylation in cancers.

RESULTS

Here we performed comprehensive analysis across multiple cancer types and identified that the decrease in H3K4me1 levels coincides with DNA hypermethylation at the bivalent promoter CGIs during tumorigenesis. Removal of DNA hypermethylation leads to increment of H3K4me1 at promoter CGIs with preference for bivalent genes. Nevertheless, the alteration of H3K4me1 by overexpressing or knockout LSD1, the demethylase of H3K4, doesn't change the level or pattern of DNA methylation. Moreover, LSD1 was found to regulate the expression of a bivalent gene OVOL2 to promote tumorigenesis. Knockdown of OVOL2 in LSD1 knockout HCT116 cells restored the cancer cell phenotype.

CONCLUSION

In summary, our work identified a universal indicator that can pre-mark DNA hypermethylation in cancer cells, and dissected the interplay between H3K4me1 and DNA hypermethylation in detail. Current study also reveals a novel mechanism underlying the oncogenic role of LSD1, providing clues for cancer therapies.

Integrative multi-omics analysis depicts the methylome and hydroxymethylome in recurrent bladder cancers and identifies biomarkers for predicting PD-L1 expression

BACKGROUND

Urinary bladder cancer (UBC) is a common malignancy of the urinary tract; however, the mechanism underlying its high recurrence and responses to immunotherapy remains unclear, making clinical outcome predictions difficult. Epigenetic alterations, especially DNA methylation, play important roles in bladder cancer development and are increasingly being investigated as biomarkers for diagnostic or prognostic predictions. However, little is known about hydroxymethylation since previous studies based on bisulfite-sequencing approaches could not differentiate between 5mC and 5hmC signals, resulting in entangled methylation results.

METHODS

Tissue samples of bladder cancer patients who underwent laparoscopic radical cystectomy (LRC), partial cystectomy (PC), or transurethral resection of bladder tumor (TURBT) were collected. We utilized a multi-omics approach to analyze both primary and recurrent bladder cancer samples. By integrating various techniques including RNA sequencing, oxidative reduced-representation bisulfite sequencing (oxRRBS), reduced-representation bisulfite sequencing (RRBS), and whole exome sequencing, a comprehensive analysis of the genome, transcriptome, methylome, and hydroxymethylome landscape of these cancers was possible.

RESULTS

By whole exome sequencing, we identified driver mutations involved in the development of UBC, including those in FGFR3, KDMTA, and KDMT2C. However, few of these driver mutations were associated with the down-regulation of programmed death-ligand 1 (PD-L1) or recurrence in UBC. By integrating RRBS and oxRRBS data, we identified fatty acid oxidation-related genes significantly enriched in 5hmC-associated transcription alterations in recurrent bladder cancers. We also observed a series of 5mC hypo differentially methylated regions (DMRs) in the gene body of NFATC1, which is highly involved in T-cell immune responses in bladder cancer samples with high expression of PD-L1. Since 5mC and 5hmC alternations are globally anti-correlated, RRBS-seq-based markers that combine the 5mC and 5hmC signals, attenuate cancer-related signals, and therefore, are not optimal as clinical biomarkers.

CONCLUSIONS

By multi-omics profiling of UBC samples, we showed that epigenetic alternations are more involved compared to genetic mutations in the PD-L1 regulation and recurrence of UBC. As proof of principle, we demonstrated that the combined measurement of 5mC and 5hmC levels by the bisulfite-based method compromises the prediction accuracy of epigenetic biomarkers.

Status of integrin subunit alpha 4 promoter DNA methylation in colorectal cancer and other malignant tumors: a systematic review and meta-analysis

Background and purpose

Although many recent studies have analyzed the validation of integrin subunit alpha 4 (ITGA4) biomarker for cancer detection in patients with various malignancies, the diagnostic value of ITGA4 methylation for malignant tumors remains uncertain. We performed a systematic review and meta-analysis to unravel the relationship between ITGA4 promoter methylation status and malignant tumors.

Experimental approach

A meta-analysis was performed using the metaphor package in R 3.5 and Meta-Disc 1.4 software. Data were derived from a search of main electronic databases up to January 2022. SROC analysis was used to evaluate the status of ITGA4 promoter methylation in colorectal cancer (CRC) and other cancers. A total of 1232 tumor samples and 649 non-tumor samples from 13 studies were analyzed.

Findings/Results

The pooled results including all types of cancer provided evidence that ITGA4 hypermethylation was more frequent in tumor samples than non-tumor samples (OR 13.32, 95% CI 7.96-22.29). Methylation of ITGA4 has a pooled sensitivity of 0.95 (95% CI: 0.94-0.97), a pooled specificity of 0.57 (95% CI: 0.54-0.60), and an area under the curve (AUC) of 0.94. When the analysis was performed independently for CRC, it revealed a higher association (OR = 20.77, 95% CI: 9.15-47.15). The assessment of ITGA4 methylation of tissue samples resulted in a pooled sensitivity of 0.99 (95% CI: 0.97-1.00) and a pooled specificity of 0.90 (95% CI: 0.86-0.93), and AUC of 0.94 for the diagnosis of CRC.

Conclusion and implications

ITGA4 methylation analysis is a reliable method for CRC screening in tissue samples.

Epigenetically regulated gene expression profiles decipher four molecular subtypes with prognostic and therapeutic implications in gastric cancer

BACKGROUND

Gastric cancer (GC) is one of the most common malignant tumors of the digestive tract which seriously endangers the health of human beings worldwide. Transcriptomic deregulation by epigenetic mechanisms plays a crucial role in the heterogeneous progression of GC. This study aimed to investigate the impact of epigenetically regulated genes on the prognosis, immune microenvironment, and potential treatment of GC.

RESULTS

Under the premise of verifying significant co-regulation of the aberrant frequencies of microRNA (miRNA) correlated (MIRcor) genes and DNA methylation-correlated (METcor) genes. Four GC molecular subtypes were identified and validated by comprehensive clustering of MIRcor and METcor GEPs in 1521 samples from five independent multicenter GC cohorts: cluster 1 was characterized by up-regulated cell proliferation and transformation pathways, with good prognosis outcomes, driven by mutations, and was sensitive to 5-fluorouracil and paclitaxel; cluster 2 performed moderate prognosis and benefited more from apatinib and cisplatin; cluster 3 was featured by an up-regulated ligand-receptor formation-related pathways, poor prognosis, an immunosuppression phenotype with low tumor purity, resistant to chemotherapy (e.g., 5-fluorouracil, paclitaxel, and cisplatin), and targeted therapy drug (apatinib) and sensitive to dasatinib; cluster 4 was characterized as an immune-activating phenotype, with advanced tumor stages, benefit more from immunotherapy and displayed worst prognosis.

CONCLUSIONS

According to the epigenetically regulated GEPs, we developed four robust GC molecular subtypes, which facilitated the understanding of the epigenetic mechanisms underlying GC heterogeneity, offering an optimized decision-making and surveillance platform for GC patients.

DNA methylation patterns suggest the involvement of DNMT3B and TET1 in osteosarcoma development

DNA methylation may be involved in the development of osteosarcomas. Osteosarcomas commonly arise during the bone growth and remodeling in puberty, making it plausible to infer the involvement of epigenetic alterations in their development. As a highly studied epigenetic mechanism, we investigated DNA methylation and related genetic variants in 28 primary osteosarcomas aiming to identify deregulated driver alterations. Methylation and genomic data were obtained using the Illumina HM450K beadchips and the TruSight One sequencing panel, respectively. Aberrant DNA methylation was spread throughout the osteosarcomas genomes. We identified 3146 differentially methylated CpGs comparing osteosarcomas and bone tissue samples, with high methylation heterogeneity, global hypomethylation and focal hypermethylation at CpG islands. Differentially methylated regions (DMR) were detected in 585 loci (319 hypomethylated and 266 hypermethylated), mapped to the promoter regions of 350 genes. These DMR genes were enriched for biological processes related to skeletal system morphogenesis, proliferation, inflammatory response, and signal transduction. Both methylation and expression data were validated in independent groups of cases. Six tumor suppressor genes harbored deletions or promoter hypermethylation (DLEC1, GJB2, HIC1, MIR149, PAX6, and WNT5A), and four oncogenes presented gains or hypomethylation (ASPSCR1, NOTCH4, PRDM16, and RUNX3). Our analysis also revealed hypomethylation at 6p22, a region that contains several histone genes. Copy-number changes in DNMT3B (gain) and TET1 (loss), as well as overexpression of DNMT3B in osteosarcomas provide a possible explanation for the observed phenotype of CpG island hypermethylation. While the detected open-sea hypomethylation likely contributes to the well-known osteosarcoma genomic instability, enriched CpG island hypermethylation suggests an underlying mechanism possibly driven by overexpression of DNMT3B likely resulting in silencing of tumor suppressors and DNA repair genes.

A DNA Methylation-based Epigenetic Signature for the Identification of Lymph Node Metastasis in T1 Colorectal Cancer

OBJECTIVE

This study aimed to unravel the lymph node metastasis (LNM)-related methylated DNA (mDNA) landscape and develop a mDNA signature to identify LNM in patients with T1 colorectal cancers (T1 CRC).

BACKGROUND

Considering the invasiveness of T1 CRC, current guidelines recommend endoscopic resection in patients with LNM-negative, and radical surgical resection only for high-risk LNM-positive patients. Unfortunately, the clinicopathological criteria for LNM risk stratification are imperfect, resulting in frequent misdiagnosis leading to unnecessary radical surgeries and postsurgical complications.

METHODS

We conducted genome-wide methylation profiling of 39 T1 CRC specimens to identify differentially methylated CpGs between LNM-positive and LNM-negative, and performed quantitative pyrosequencing analysis in 235 specimens from 3 independent patient cohorts, including 195 resected tissues (training cohort: n=128, validation cohort: n=67) and 40 pretreatment biopsies.

RESULTS

Using logistic regression analysis, we developed a 9-CpG signature to distinguish LNM-positive versus LNM-negative surgical specimens in the training cohort [area under the curve (AUC)=0.831, 95% confidence interval (CI)=0.755-0.892; P <0.0001], which was subsequently validated in additional surgical specimens (AUC=0.825; 95% CI=0.696-0.955; P =0.003) and pretreatment biopsies (AUC=0.836; 95% CI=0.640-1.000, P =0.0036). This diagnostic power was further improved by combining the signature with conventional clinicopathological features.

CONCLUSIONS

We established a novel epigenetic signature that can robustly identify LNM in surgical specimens and even pretreatment biopsies from patients with T1 CRC. Our signature has strong translational potential to improve the selection of high-risk patients who require radical surgery while sparing others from its complications and expense.

Examination of the Functional Relationship between PD-L1 DNA Methylation and mRNA Expression in Non-Small-Cell Lung Cancer

Immunotherapy targeting the interaction between programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1) is a treatment option for patients with non-small-cell lung cancer (NSCLC). The expression of PD-L1 by the NSCLC cells determines treatment effectiveness, but the relationship between PD-L1 DNA methylation and expression has not been clearly described. We investigated PD-L1 DNA methylation, mRNA expression, and protein expression in NSCLC cell lines and tumor biopsies. We used clustered regularly interspaced short palindromic repeats-associated protein 9 (CRISPR-Cas9) to modify PD-L1 genetic contexts and endonuclease deficient Cas9 (dCas9) fusions with ten-eleven translocation methylcytosine dioxygenase 1 (TET1) and DNA (cytosine-5)-methyltransferase 3A (DNMT3A) to manipulate PD-L1 DNA methylation. In NSCLC cell lines, we identified specific PD-L1 CpG sites with methylation levels inversely correlated with PD-L1 mRNA expression. However, inducing PD-L1 mRNA expression with interferon-γ did not decrease the methylation level for these CpG sites, and using CRISPR-Cas9, we found that the CpG sites did not directly confer a negative regulation. dCas9-TET1 and dCas9-DNMT3A could induce PD-L1 hypo- and hyper-methylation, respectively, with the latter conferring a decrease in expression showing the functional impact of methylation. In NSCLC biopsies, the inverse correlation between the methylation and expression of PD-L1 was weak. We conclude that there is a regulatory link between PD-L1 DNA methylation and expression. However, since these measures are weakly associated, this study highlights the need for further research before PD-L1 DNA methylation can be implemented as a biomarker and drug target for measures to improve the effectiveness of PD-1/PD-L1 immunotherapy in NSCLC.

Differentiated oxidation modes of guanine between CpG and 5mCpG by a photoactivatable Pt(IV) anticancer prodrug

CpG and its cytosine-methylated counterpart (^5mCpG) are a unique reversible pair of sequences in regulating the expression of genes epigenetically. As DNA is the potential target of Pt-based anticancer metallodrugs, herein, we comparatively investigate the interactions of 5'-CpG and 5'-^5mCpG with a photoactivatable anticancer Pt(IV) prodrug, trans,trans,trans-[Pt^IV(N₃)₂(OH)₂(py)₂] (1; py = pyridine), to explore the effects of methylation on the platination and ROS-induced oxidation of the CpG motif. Mono-platinated dinucleotides were demonstrated by ESI-MS to be the main products for both 5'-CpG and 5'-^5mCpG with the bound Pt moiety as [Pt^II(N₃)(py)₂] generated by the photodecomposition of complex 1 under irradiation with blue light, accompanied by the formation of less abundant di-platinated adducts. G-N7 and C-N3/^5mC-N3 were shown to be the major and minor platination sites, respectively, with G-N1 as the third and weakest platination site, in particular, in di-platinated products. Moreover, platinated dinucleotides associated with guanine and/or cytosine oxidation were also observed. Apart from 8-oxo-guanine (^oxG) and N-formylamidoiminohydantoin (RedSp) reported previously, novel oxidation adducts 5-guanidinohydantoin (Gh) derived from guanine and 1-carbamoyl-4,5-dihydroxy-2-oxoimidazolidine (ImidCyt) derived from cytosine in CpG, and diimino imidazole (DIz) and 2,5-diaminoimidazol-4-one (imidazolone, Iz) derived from guanine and Imid^5mCyt derived from ^5mC in ^5mCpG were proposed according to MS information. These results showed that methylation exerted little effects on the platination modes of CpG, but triggered distinct oxidation pathways of CpG, perhaps causing discriminated DNA damage to CpG-rich genes. This work provides novel insights into the role of the anticancer photoactivatable Pt(IV) prodrug through damaging the epigenetically modified DNA sequences.

Value of Methylation Status of RPRM, SDC2, and TCF4 Genes in Plasma for Gastric Adenocarcinoma Screening

Objective

To explore the clinical value of the combined screening of the methylation statuses of the RPRM, SDC2, and TCF4 genes in plasma of gastric cancer patients.

Methods

Differential expressed genes (DEGs) were selected from the Gene Expression Omnibus database, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed using DAVID, and a protein-protein interaction network was constructed. Hub genes were obtained using Cytoscape. Screening results combined with literature reports identified three genes (RPRM, SDC2, and TCF4). Further analysis was done using biopsies collected through gastroscopy at Shanxi Cancer Hospital from January 8, 2020 to February 22, 2021. The patients were divided into two groups: gastric adenocarcinoma group, and control group which are not gastric adenocarcinoma according to pathological or gastroscopic results. The methylation statuses of the three genes in peripheral blood plasma were detected by fluorescence polymerase chain reaction, and the relationships between the positive rates of the three combined genes with pathology and/or gastroscopy results were analyzed. The clinical value of the combined detection of the three genes was evaluated according to these indicators. The diagnostic specificity and sensitivity of this detective method were analyzed.

Results

A total of 197 DEGs were identified and 12 hub genes were obtained. The enriched functions and pathways of DEGs include regulation of cell proliferation, extracellular space, cytokine activity, and pathways in cancer. The combination of RPRM, SDC2, and TCF4 gene methylation had a specificity of 93.39% and sensitivity of 80.33%. The combined positive rate of RPRM, SDC2, and TCF4 gene methylation in patients with gastric adenocarcinoma was significantly higher compared with those without gastric adenocarcinoma (χ²=151.179, P<0.05).

Conclusion

Combined detection of RPRM, SDC2, and TCF4 gene methylation in peripheral blood plasma maybe helpful in screening for gastric adenocarcinoma, and maybe a complementary method to gastroscopy and serum tumor markers.

Comprehensive Pan-Cancer Analysis of KIF18A as a Marker for Prognosis and Immunity

KIF18A belongs to the Kinesin family, which participates in the occurrence and progression of tumors. However, few pan-cancer analyses have been performed on KIF18A to date. We used multiple public databases such as TIMER, The Cancer Genome Atlas (TCGA), Genotype-Tissue Expression (GTEx), and Human Protein Atlas (HPA) to explore KIF18A mRNA expression in 33 tumors. We performed immunohistochemistry on liver cancer and pancreatic cancer tissues and corresponding normal tissues to examine the expression of KIF18A protein. Univariate Cox regression and Kaplan-Meier survival analysis were applied to detect the effect of KIF18A on overall survival (OS), disease-specific survival (DSS), and progression-free interval (PFI) of patients with these tumors. Subsequently, we explored KIF18A gene alterations in different tumor tissues using cBioPortal. The relationship between KIF18A and clinical characteristics, tumor microenvironment (TME), immune regulatory genes, immune checkpoints, tumor mutational burden (TMB), microsatellite instability (MSI), mismatch repairs (MMRs), DNA methylation, RNA methylation, and drug sensitivity was applied for further study using the R language. Gene Set Enrichment Analysis (GSEA) was utilized to explore the molecular mechanism of KIF18A. Bioinformatic analysis and immunohistochemical experiments confirmed that KIF18A was up-regulated in 27 tumors and was correlated with the T stage, N stage, pathological stage, histological grade, and Ki-67 index in many cancers. The overexpression of KIF18A had poor OS, DSS, and PFI in adrenocortical carcinoma (ACC), kidney renal clear cell carcinoma (KIRC), kidney renal papillary cell carcinoma (KIRP), brain lower-grade glioma (LGG), liver cancer (LIHC), lung adenocarcinoma (LUAD), and pancreatic cancer (PAAD). Univariate and multivariate regression analysis confirmed KIF18A as an independent prognostic factor for LIHC and PAAD. The mutation frequency of KIF18A is the highest in endometrial cancer. KIF18A expression levels were positively associated with immunocyte infiltration, immune regulatory genes, immune checkpoints, TMB, MSI, MMRs, DNA methylation, RNA methylation, and drug sensitivity in certain cancers. In addition, we discovered that KIF18A participated in the cell cycle at the single-cell level and GSEA analysis for most cancers. These findings suggested that KIF18A could be regarded as a latent prognostic marker and a new target for cancer immunological therapy.

Identification of Differentially Methylated Genes Associated with Clear Cell Renal Cell Carcinoma and Their Prognostic Values

Objective

Renal cell carcinoma (RCC) is a heterogeneous disease comprising histologically defined subtypes among which clear cell RCC (ccRCC) accounts for 70% of all RCC cases. DNA methylation constitutes a main part of the molecular mechanism of cancer evolution and prognosis. In this study, we aim to identify differentially methylated genes related to ccRCC and their prognostic values.

Methods

The GSE168845 dataset was downloaded from the Gene Expression Omnibus (GEO) database to identify differentially expressed genes (DEGs) between ccRCC tissues and paired tumor-free kidney tissues. DEGs were submitted to public databases for functional and pathway enrichment analysis, protein-protein interaction (PPI) analysis, promoter methylation analysis, and survival correlation analysis.

Results

In the setting of |log2FC| ≥ 2 and adjusted p value <0.05 during differential expression analysis of the GSE168845 dataset, 1659 DEGs between ccRCC tissues and paired tumor-free kidney tissues were sorted out. The most enriched pathways were "T cell activation" and "cytokine-cytokine receptor interaction." After PPI analysis, 22 hub genes related to ccRCC stood out, among which CD4, PTPRC, ITGB2, TYROBP, BIRC5, and ITGAM exhibited higher methylation levels, and BUB1B, CENPF, KIF2C, and MELK exhibited lower methylation levels in ccRCC tissues compared with paired tumor-free kidney tissues. Among these differentially methylated genes, TYROBP, BIRC5, BUB1B, CENPF, and MELK were significantly correlated with the survival of ccRCC patients (p < 0.001).

Conclusion

Our study indicates the DNA methylation of TYROBP, BIRC5, BUB1B, CENPF, and MELK may be promising results for the prognosis of ccRCC.

Epigenetic changes induced by pathogenic Chlamydia spp

Chlamydia trachomatis, C. pneumoniae, and C. psittaci, the three Chlamydia species known to cause human disease, have been collectively linked to several pathologies, including conjunctivitis, trachoma, respiratory disease, acute and chronic urogenital infections and their complications, and psittacosis. In vitro, animal, and human studies also established additional correlations, such as between C. pneumoniae and atherosclerosis and between C. trachomatis and ovarian cancer. As part of their survival and pathogenesis strategies as obligate intracellular bacteria, Chlamydia spp. modulate all three major types of epigenetic changes, which include deoxyribonucleic acid (DNA) methylation, histone post-translational modifications, and microRNA-mediated gene silencing. Some of these epigenetic changes may be implicated in key aspects of pathogenesis, such as the ability of the Chlamydia spp. to induce epithelial-to-mesenchymal transition, interfere with DNA damage repair, suppress cholesterol efflux from infected macrophages, act as a co-factor in human papillomavirus (HPV)-mediated cervical cancer, prevent apoptosis, and preserve the integrity of mitochondrial networks in infected host cells. A better understanding of the individual and collective contribution of epigenetic changes to pathogenesis will enhance our knowledge about the biology of Chlamydia spp. and facilitate the development of novel therapies and biomarkers. Pathogenic Chlamydia spp. contribute to epigenetically-mediated gene expression changes in host cells by multiple mechanisms.

Insights into the role of nucleotide methylation in metabolic-associated fatty liver disease

Metabolic-associated fatty liver disease (MAFLD) is a chronic liver disease characterized by fatty infiltration of the liver. In recent years, the MAFLD incidence rate has risen and emerged as a serious public health concern. MAFLD typically progresses from the initial hepatocyte steatosis to steatohepatitis and then gradually advances to liver fibrosis, which may ultimately lead to cirrhosis and carcinogenesis. However, the potential evolutionary mechanisms still need to be clarified. Recent studies have shown that nucleotide methylation, which was directly associated with MAFLD's inflammatory grading, lipid synthesis, and oxidative stress, plays a crucial role in the occurrence and progression of MAFLD. In this review, we highlight the regulatory function and associated mechanisms of nucleotide methylation modification in the progress of MAFLD, with a particular emphasis on its regulatory role in the inflammation of MAFLD, including the regulation of inflammation-related immune and metabolic microenvironment. Additionally, we summarize the potential value of nucleotide methylation in the diagnosis and treatment of MAFLD, intending to provide references for the future investigation of MAFLD.

Aging: Epigenetic modifications

Aging is one of the most complex and irreversible health conditions characterized by continuous decline in physical/mental activities that eventually poses an increased risk of several diseases and ultimately death. These conditions cannot be ignored by anyone but there are evidences that suggest that exercise, healthy diet and good routines may delay the Aging process significantly. Several studies have demonstrated that Epigenetics plays a key role in Aging and Aging-associated diseases through methylation of DNA, histone modification and non-coding RNA (ncRNA). Comprehension and relevant alterations in these epigenetic modifications can lead to new therapeutic avenues of age-delaying contrivances. These processes affect gene transcription, DNA replication and DNA repair, comprehending epigenetics as a key factor in understanding Aging and developing new avenues for delaying Aging, clinical advancements in ameliorating aging-related diseases and rejuvenating health. In the present article, we have described and advocated the epigenetic role in Aging and associated diseases.

Association between multiple gene promoter hypermethylation and the risk of gastric cancer: A systematic review and meta-analysis

BACKGROUND

Several studies have demonstrated an association between multiple gene hypermethylation and gastric cancer. However, the intrinsic mechanisms remain elusive and highly debatable. To this end, our study aims to investigate the correlation between the methylation status of multiple gene promoters and gastric cancer.

METHODS

PubMed, EMBASE, CNKI, WanFang, Cqvip, and Cochrane Library were queried from inception to May 2021, and the relationship between the methylation status of the CpG islands and gastric cancer risk was systematically assessed under the inclusion and exclusion criteria. The incidence of DNA methylation between tumor and non-tumor tissues was compared, and the clinicopathological significance of DNA methylation in gastric carcinoma was further evaluated. The odds ratio (OR) was estimated with a 95% confidence interval (CI), and forest plots were generated using the fixed-effects or random-effects model.

RESULTS

In total, 201 studies were enrolled, and a higher frequency of CpG islands methylation was identified in gastric cancer tissues than in non-neoplastic tissues. This suggests that aberrant polygene methylation might be associated with the initial onset and progression of gastric cancer.

CONCLUSION

This study sheds light on the significance of polygene methylation status in gastric cancer. The DNA methylation of these genes may serve as underlying epigenetic biomarkers, providing a promising molecular diagnostic approach for human gastric cancer clinical diagnosis. More large randomized trials are needed to confirm the findings.

Spatial Transcriptomic Analysis of Ovarian Cancer Precursors Reveals Reactivation of IGFBP2 during Pathogenesis

Elucidating the earliest pathogenic steps in cancer development is fundamental to improving its early detection and prevention. Ovarian high-grade serous carcinoma (HGSC), a highly aggressive cancer, mostly originates from the fallopian tube epithelium through a precursor stage, serous tubal intraepithelial carcinoma (STIC). In this study, we performed spatial transcriptomic analysis to compare STICs, carcinoma, and their matched normal fallopian tube epithelium. Several differentially expressed genes in STICs and carcinomas were involved in cancer metabolism and detected in a larger independent transcriptomic dataset of ovarian HGSCs. Among these, insulin-like growth factor binding protein-2 (IGFBP2) was found to undergo DNA hypomethylation and to be increased at the protein level in STICs. Pyrosequencing revealed an association of IGFBP2 expression with the methylation state of its proximal enhancer, and 5-azacytidine treatment increased IGFBP2 expression. In postmenopausal fallopian tubes, where most STICs are detected, IGFBP2 immunoreactivity was detected in all 38 proliferatively active STICs but was undetectable in morphologically normal tubal epithelia, including those with TP53 mutations. In premenopausal fallopian tubes, IGFBP2 expression was limited to the secretory epithelium at the proliferative phase, and estradiol treatment increased IGFBP2 expression levels. IGFBP2 knockdown suppressed the growth of IGFBP2-expressing tubal epithelial cells via inactivation of the AKT pathway. Taken together, demethylation of the proximal enhancer of IGFBP2 drives tumor development by maintaining the increased IGFBP2 required for proliferation in an otherwise estrogen-deprived, proliferation-quiescent, and postmenopausal tubal microenvironment.

SIGNIFICANCE

Molecular studies of the earliest precursor lesions of ovarian cancer reveal a role of IGFBP2 in propelling tumor initiation, providing new insights into ovarian cancer development.