Promoter hypermethylation of tumour suppressor genes as potential biomarkers in colorectal cancer

Novel DNA methylation biomarkers for early diagnosis of oral tongue squamous cell carcinoma (OTSCC)

Oral tongue squamous cell carcinoma (OTSCC) is the most common malignancy type among males across the world. However, analysis of molecular markers could be useful in detecting the early-stage OTSCC, which would allow optimal clinical treatments and prolong the survival rate of patients consequently. The study has the objective of detecting the role of salivary biomarkers based on gene promoter hypermethylation. Sample data from 45 OTSCC and normal groups were analyzed to exhibit the methylation levels of salivary biomarkers (TRH, FHIT, MGMT, p16, and RASSF1A). The specificity and sensitivity analysis of methylation biomarkers was conducted in addition to the receiver operating characteristic (ROC) curve for both early-stage and advanced OTSCC stages. Quantitative data findings showed the perfect sensitivity and specificity for TRH, MGMT, p16, and RASSF1A with 100%, and > 90%, respectively. In addition, the results indicated an inefficient area under curves (> 0.7) for these biomarkers to detect the OTSCC. There were no significant differences observed between TRH and FHIT and p16 and MGMT based on the Wilcoxon signed-rank test. The methylation statuses of genes TRH, RASSF1A, p16, and MGMT might become utilized as predictive biomarkers for clinical application in early diagnosis of OTSCC and noninvasive oral cancer screening.

Natural Stilbenes: Their Role in Colorectal Cancer Prevention, DNA Methylation, and Therapy

The resistance of colorectal cancer (CRC) to conventional therapeutic modalities, such as radiation therapy and chemotherapy, along with the associated side effects, significantly limits effective anticancer strategies. Numerous epigenetic investigations have unveiled that naturally occurring stilbenes can modify or reverse abnormal epigenetic alterations, particularly aberrant DNA methylation status, offering potential avenues for preventing or treating CRC. By modulating the activity of the DNA methylation machinery components, phytochemicals may influence the various stages of CRC carcinogenesis through multiple molecular mechanisms. Several epigenetic studies, especially preclinical research, have highlighted the effective DNA methylation modulatory effects of stilbenes with minimal adverse effects on organisms, particularly in combination therapies for CRC. However, the available preclinical and clinical data regarding the effects of commonly encountered stilbenes against CRC are currently limited. Therefore, additional epigenetic research is warranted to explore the preventive potential of these phytochemicals in CRC development and to validate their therapeutic application in the prevention and treatment of CRC. This review aims to provide an overview of selected bioactive stilbenes as potential chemopreventive agents for CRC with a focus on their modulatory mechanisms of action, especially in targeting alterations in DNA methylation machinery in CRC.

Unmasking early colorectal cancer clues: in silico and in vitro investigation of downregulated IGF2, SOCS1, MLH1, and CACNA1G in SSA polyps

BACKGROUND AND AIM

Colorectal cancer (CRC) originates from pre-existing polyps in the colon. The development of different subtypes of CRC is influenced by various genetic and epigenetic characteristics. CpG island methylator phenotype (CIMP) is found in about 15-20% of sporadic CRCs and is associated with hypermethylation of certain gene promoters. This study aims to find prognostic genes and compare their expression and methylation status as potential biomarkers in patients with serrated sessile adenomas/polyps (SSAP) and CRC, in order to evaluate which, one is a better predictor of disease.

METHOD

This study employed a multi-phase approach to investigate genes associated with CRC and SSAP. Initially, two gene expression datasets were analyzed using R and Limma package to identify differentially expressed genes (DEGs). Venn diagram analysis further refined the selection, revealing four genes from the Weissenberg panel with significant changes. These genes, underwent thorough in silico evaluations. Once confirmed, they proceeded to wet lab experimentation, focusing on expression and methylation status. This comprehensive methodology ensured a robust examination of the genes involved in CRC and SSAP.

RESULT

This study identified cancer-specific genes, with 8,351 and 1,769 genes specifically down-regulated in SSAP and CRC tissues, respectively. The down-regulated genes were associated with cell adhesion, negative regulation of cell proliferation, and drug response. Four highly downregulated genes in the Weissenberg panel, including CACNA1G, IGF2, MLH1, and SOCS1. In vitro analysis showed that they are hypermethylated in both SSAP and CRC samples while their expressions decreased only in CRC samples.

CONCLUSION

This suggests that the decrease in gene expression could help determine whether a polyp will become cancerous. Using both methylation status and gene expression status of genes in the Weissenberg panel in prognostic tests may lead to better prognoses for patients.

Colorectal cancer microbiome programs DNA methylation of host cells by affecting methyl donor metabolism

BACKGROUND

Colorectal cancer (CRC) arises from complex interactions between host and environment, which include the gut and tissue microbiome. It is hypothesized that epigenetic regulation by gut microbiota is a fundamental interface by which commensal microbes dynamically influence intestinal biology. The aim of this study is to explore the interplay between gut and tissue microbiota and host DNA methylation in CRC.

METHODS

Metagenomic sequencing of fecal samples was performed on matched CRC patients (n = 18) and healthy controls (n = 18). Additionally, tissue microbiome was profiled with 16S rRNA gene sequencing on tumor (n = 24) and tumor-adjacent normal (n = 24) tissues of CRC patients, while host DNA methylation was assessed through whole-genome bisulfite sequencing (WGBS) in a subset of 13 individuals.

RESULTS

Our analysis revealed substantial alterations in the DNA methylome of CRC tissues compared to adjacent normal tissues. An extensive meta-analysis, incorporating publicly available and in-house data, identified significant shifts in microbial-derived methyl donor-related pathways between tumor and adjacent normal tissues. Of note, we observed a pronounced enrichment of microbial-associated CpGs within the promoter regions of genes in adjacent normal tissues, a phenomenon notably absent in tumor tissues. Furthermore, we established consistent and recurring associations between methylation patterns of tumor-related genes and specific bacterial taxa.

CONCLUSIONS

This study emphasizes the pivotal role of the gut microbiota and pathogenic bacteria in dynamically shaping DNA methylation patterns, impacting physiological homeostasis, and contributing to CRC tumorigenesis. These findings provide valuable insights into the intricate host-environment interactions in CRC development and offer potential avenues for therapeutic interventions in this disease.

Associations in cell type-specific hydroxymethylation and transcriptional alterations of pediatric central nervous system tumors

Although intratumoral heterogeneity has been established in pediatric central nervous system tumors, epigenomic alterations at the cell type level have largely remained unresolved. To identify cell type-specific alterations to cytosine modifications in pediatric central nervous system tumors, we utilize a multi-omic approach that integrated bulk DNA cytosine modification data (methylation and hydroxymethylation) with both bulk and single-cell RNA-sequencing data. We demonstrate a large reduction in the scope of significantly differentially modified cytosines in tumors when accounting for tumor cell type composition. In the progenitor-like cell types of tumors, we identify a preponderance differential Cytosine-phosphate-Guanine site hydroxymethylation rather than methylation. Genes with differential hydroxymethylation, like histone deacetylase 4 and insulin-like growth factor 1 receptor, are associated with cell type-specific changes in gene expression in tumors. Our results highlight the importance of epigenomic alterations in the progenitor-like cell types and its role in cell type-specific transcriptional regulation in pediatric central nervous system tumors.

Early screening of colorectal cancer using feature engineering with artificial intelligence-enhanced analysis of nanoscale chromatin modifications

Colonoscopy is accurate but inefficient for colorectal cancer (CRC) prevention due to the low (~ 7 to 8%) prevalence of target lesions, advanced adenomas. We leveraged rectal mucosa to identify patients who harbor CRC field carcinogenesis by evaluating chromatin 3D architecture. Supranucleosomal disordered chromatin chains (~ 5 to 20 nm, ~1 kbp) fold into chromatin packing domains (~ 100 to 200 nm, ~ 100 to 1000 kbp). In turn, the fractal-like conformation of DNA within chromatin domains and the folding of the genome into packing domains has been shown to influence multiple facets of gene transcription, including the transcriptional plasticity of cancer cells. We deployed an optical spectroscopic nanosensing technique, chromatin-sensitive partial wave spectroscopic microscopy (csPWS), to evaluate the packing density scaling D of the chromatin chain conformation within packing domains from rectal mucosa in 256 patients with varying degrees of progression to colorectal cancer. We found average packing scaling D of chromatin domains was elevated in tumor cells, histologically normal-appearing cells 4 cm proximal to the tumor, and histologically normal-appearing rectal mucosa compared to cells from control patients (p < 0.001). Nuclear D had a robust correlation with the model of 5-year risk of CRC with r2 = 0.94. Furthermore, rectal D was evaluated as a screening biomarker for patients with advanced adenomas presenting an AUC of 0.85 and 85% sensitivity and specificity. artificial intelligence-enhanced csPWS improved diagnostic performance with AUC = 0.90. Considering the low sensitivity of existing CRC tests, including liquid biopsies, to early-stage cancers our work highlights the potential of chromatin biomarkers of field carcinogenesis in detecting early, significant precancerous colon lesions.

Identifying regulators of aberrant stem cell and differentiation activity in colorectal cancer using a dual endogenous reporter system

Aberrant stem cell-like activity and impaired differentiation are central to the development of colorectal cancer (CRC). To identify functional mediators of these key cellular programs, we engineer a dual endogenous reporter system by genome-editing the SOX9 and KRT20 loci of human CRC cell lines to express fluorescent reporters, broadcasting aberrant stem cell-like and differentiation activity, respectively. By applying a CRISPR screen targeting 78 epigenetic regulators with 542 sgRNAs to this platform, we identify factors that contribute to stem cell-like activity and differentiation in CRC. Perturbation single cell RNA sequencing (Perturb-seq) of validated hits nominate SMARCB1 of the BAF complex (also known as SWI/SNF) as a negative regulator of differentiation across an array of neoplastic colon models. SMARCB1 is a dependency and required for in vivo growth of human CRC models. These studies highlight the utility of biologically designed endogenous reporter platforms to uncover regulators with therapeutic potential.

Comprehensive profiling of DNA methylation in Korean patients with colorectal cancer

Alterations in DNA methylation play an important pathophysiological role in the development and progression of colorectal cancer. We comprehensively profiled DNA methylation alterations in 165 Korean patients with colorectal cancer (CRC), and conducted an in-depth investigation of cancer-specific methylation patterns. Our analysis of the tumor samples revealed a significant presence of hypomethylated probes, primarily within the gene body regions; few hypermethylated sites were observed, which were mostly enriched in promoter-like and CpG island regions. The CpG Island Methylator PhenotypeHigh (CIMP-H) exhibited notable enrichment of microsatellite instability-high (MSI-H). Additionally, our findings indicated a significant correlation between methylation of the MLH1 gene and MSI-H status. Furthermore, we found that the CIMP-H had a higher tendency to affect the right-side of the colon tissues and was slightly more prevalent among older patients. Through our methylome profile analysis, we successfully verified the thylation patterns and clinical characteristics of Korean patients with CRC. This valuable dataset lays a strong foundation for exploring novel molecular insights and potential therapeutic targets for the treatment of CRC. [BMB Reports 2024; 57(2): 110-115].

Colorectal cancer: Genetic alterations, novel biomarkers, current therapeutic strategies and clinical trials

Colorectal cancer (CRC) is the third most commonly detected cancer with a serious global health issue. The rates for incidence and mortality for CRC are alarming, especially since the prognosis is abysmal when the CRC is diagnosed at an advanced or metastatic stage. Both type of (modifiable/ non-modifiable) types of risk factors are established for CRC. Despite the advances in recent technology and sophisticated research, the survival rate is still meager due to delays in diagnosis. Therefore, there is urgently required to identify critical biomarkers aiming at early diagnosis and improving effective therapeutic strategies. Additionally, a complete understanding of the dysregulated pathways like PI3K/Akt, Notch, and Wnt associated with CRC progression and metastasis is very beneficial in designing a therapeutic regimen. This review article focused on the dysregulated signaling pathways, genetics and epigenetics alterations, and crucial biomarkers of CRC. This review also provided the list of clinical trials targeting signaling cascades and therapies involving small molecules. This review discusses up-to-date information on novel diagnostic and therapeutic strategies alongside specific clinical trials.

Utilizing a dual endogenous reporter system to identify functional regulators of aberrant stem cell and differentiation activity in colorectal cancer

Aberrant stem cell-like activity and impaired differentiation are central to the development of colorectal cancer (CRC). To identify functional mediators that regulate these key cellular programs in CRC, we developed an endogenous reporter system by genome-editing human CRC cell lines with knock-in fluorescent reporters at the SOX9 and KRT20 locus to report aberrant stem cell-like activity and differentiation, respectively, and then performed pooled genetic perturbation screens. Constructing a dual reporter system that simultaneously monitored aberrant stem cell-like and differentiation activity in the same CRC cell line improved our signal to noise discrimination. Using a focused-library CRISPR screen targeting 78 epigenetic regulators with 542 sgRNAs, we identified factors that contribute to stem cell-like activity and differentiation in CRC. Perturbation single cell RNA sequencing (Perturb-seq) of validated hits nominated SMARCB1 of the BAF complex (also known as SWI/SNF) as a negative regulator of differentiation across an array of neoplastic colon models. SMARCB1 is a dependency in CRC and required for in vivo growth of human CRC models. These studies highlight the utility of a biologically designed endogenous reporter system to uncover novel therapeutic targets for drug development.

Tumor circulating biomarkers in colorectal cancer

CRC is a major global health concern and is responsible for a significant number of cancer-related deaths each year. The successful treatment of CRC becomes more difficult when it goes undetected until it has advanced to a later stage. Diagnostic biomarkers can play a critical role in the early detection of CRC, which leads to improved patient outcomes and increased survival rates. It is important to develop reliable biomarkers for the early detection of CRC to enable timely diagnosis and treatment. To date, CRC detection methods such as endoscopy, blood, and stool tests are imperfect and often only identify cases in the later stages of the disease. To overcome these limitations, researchers are turning to molecular biomarkers as a promising avenue for improving CRC detection. Diagnostic information can be provided more reliably through a noninvasive approach using biomarkers such as mRNA, circulating cell-free DNA, micro-RNA, long non-coding RNA, and proteins. These biomarkers can be found in blood, tissue, feces, and volatile organic compounds. The identification of molecular biomarkers with high sensitivity and specificity for early detection of CRC that are safe, cost-effective, and easily measurable remains a significant challenge for researchers. In this article, we will explore the latest advancements in blood-based diagnostic biomarkers for CRC and their potential impact on improving patient survival rates.

Network Pharmacology Combined with Molecular Docking, Molecular Dynamics, and In Vitro Experimental Validation Reveals the Therapeutic Potential of Thymus vulgaris L. Essential Oil (Thyme Oil) against Human Breast Cancer

Breast cancer is a major global health issue for women. Thyme oil, extracted from Thymus vulgaris L., has shown promising anticancer effects. In the present study, we investigated how Thyme oil can influence breast cancer treatment using a multimethod approach. We used network pharmacology to identify the active compounds of Thyme oil, their molecular targets, and the pathways involved in breast cancer. We found that Thyme oil can modulate several key proteins (EGFR, AKT1, ESR1, HSP90AA1, STAT-3, SRC, IL-6, HIF1A, JUN, and BCL2) and pathways (EGFR tyrosine kinase inhibitor resistance, prolactin signaling pathway, HIF-1 signaling pathway, estrogen signaling pathway, ERBB signaling pathway, AGE-RAGE signaling pathway, JAK-STAT signaling pathway, FoxO signaling pathway, and PI3K-AKT signaling pathway) related to breast cancer progression. We then used molecular docking and dynamics to study the interactions and stability of the Thyme oil-compound complexes. We discovered three potent compounds (aromadendrene, α-humulene, and viridiflorene) that can bind strongly to important breast cancer proteins. We also performed in vitro experiments on MCF-7 cells to confirm the cytotoxicity and antiproliferative effects of Thyme oil. We observed that Thyme oil can inhibit cancer cell growth and proliferation at a concentration of 365.37 μg/mL. Overall, our results provide a comprehensive understanding of the pharmacological mechanism of Thyme oil in breast cancer treatment and suggest its potential as a new or adjuvant therapy. Further studies are needed to validate and optimize the therapeutic efficacy of Thyme oil and its active compounds.

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.

The outpost against cancer: universal cancer only markers

Cancer is the leading cause of death worldwide. Early detection of cancer can lower the mortality of all types of cancer; however, effective early-detection biomarkers are lacking for most types of cancers. DNA methylation has always been a major target of interest because DNA methylation usually occurs before other detectable genetic changes. While investigating the common features of cancer using a novel guide positioning sequencing for DNA methylation, a series of universal cancer only markers (UCOMs) have emerged as strong candidates for effective and accurate early detection of cancer. While the clinical value of current cancer biomarkers is diminished by low sensitivity and/or low specificity, the unique characteristics of UCOMs ensure clinically meaningful results. Validation of the clinical potential of UCOMs in lung, cervical, endometrial, and urothelial cancers further supports the application of UCOMs in multiple cancer types and various clinical scenarios. In fact, the applications of UCOMs are currently under active investigation with further evaluation in the early detection of cancer, auxiliary diagnosis, treatment efficacy, and recurrence monitoring. The molecular mechanisms by which UCOMs detect cancers are the next important topics to be investigated. The application of UCOMs in real-world scenarios also requires implementation and refinement.

CRISPR-based epigenome editing: mechanisms and applications

Epigenomic anomalies contribute significantly to the development of numerous human disorders. The development of epigenetic research tools is essential for understanding how epigenetic marks contribute to gene expression. A gene-editing technique known as CRISPR (clustered regularly interspaced short palindromic repeats) typically targets a particular DNA sequence using a guide RNA (gRNA). CRISPR/Cas9 technology has been remodeled for epigenome editing by generating a 'dead' Cas9 protein (dCas9) that lacks nuclease activity and juxtaposing it with an epigenetic effector domain. Based on fusion partners of dCas9, a specific epigenetic state can be achieved. CRISPR-based epigenome editing has widespread application in drug screening, cancer treatment and regenerative medicine. This paper discusses the tools developed for CRISPR-based epigenome editing and their applications.

Early screening of colorectal cancer using feature engineering with artificial intelligence-enhanced analysis of nanoscale chromatin modifications

Colonoscopy is accurate but inefficient for colorectal cancer (CRC) prevention due to the low (~ 7-8%) prevalence of target lesions, advanced adenomas. We leveraged rectal mucosa to identify patients who harbor CRC field carcinogenesis by evaluating chromatin 3D architecture. Supranucleosomal disordered chromatin chains (~ 5-20 nm, ~ 1 kbp) fold into chromatin packing domains (~ 100-200 nm, ~ 100-1,000 kbp). In turn, the fractal-like conformation of DNA within chromatin domains and the folding of the genome into packing domains has been shown to influence multiple facets of gene transcription, including the transcriptional plasticity of cancer cells. We deployed an optical spectroscopic nanosensing technique, chromatin-sensitive partial wave spectroscopic microscopy (csPWS), to evaluate the packing density scaling D of the chromatin chain conformation within packing domains from rectal mucosa in 256 patients with varying degrees of progression to colorectal cancer. We found average packing scaling D of chromatin domains was elevated in tumor cells, histologically normal-appearing cells 4 cm proximal to the tumor, and histologically normal-appearing rectal mucosa compared to cells from control patients (p < 0.001). Nuclear D had a robust correlation with the model of 5-year risk of CRC with r2 = 0.94. Furthermore, rectal D was evaluated as a screening biomarker for patients with advanced adenomas presenting an AUC of 0.85 and 85% sensitivity and specificity. Artificial Intelligence (AI)-enhanced csPWS improved diagnostic performance with AUC = 0.90. Considering the low sensitivity of existing CRC tests, including liquid biopsies, to early-stage cancers our work highlights the potential of chromatin biomarkers of field carcinogenesis in detecting early, significant precancerous colon lesions.

Early screening of colorectal cancer using feature engineering with artificial intelligence-enhanced analysis of nanoscale chromatin modifications

Colonoscopy is accurate but inefficient for colorectal cancer (CRC) prevention due to the low (~7-8%) prevalence of target lesions, advanced adenomas. We leveraged rectal mucosa to identify patients who harbor CRC field carcinogenesis by evaluating chromatin 3D architecture. Supranucleosomal disordered chromatin chains (~5-20 nm, ~1 kbp) fold into chromatin packing domains (~100-200 nm, ~100-1,000 kbp). In turn, the fractal-like conformation of DNA within chromatin domains and the folding of the genome into packing domains has been shown to influence multiple facets of gene transcription, including the transcriptional plasticity of cancer cells. We deployed an optical spectroscopic nanosensing technique, chromatin-sensitive partial wave spectroscopic microscopy (csPWS), to evaluate the packing density scaling D of the chromatin chain conformation within packing domains from rectal mucosa in 256 patients with varying degrees of progression to colorectal cancer. We found average packing scaling D of chromatin domains was elevated in tumor cells, histologically normal-appearing cells 4 cm proximal to the tumor, and histologically normal-appearing rectal mucosa compared to cells from control patients (p<0.001). Nuclear D had a robust correlation with the model of 5-year risk of CRC with r2=0.94. Furthermore, rectal D was evaluated as a screening biomarker for patients with advanced adenomas presenting an AUC of 0.85 and 85% sensitivity and specificity. Artificial Intelligence (AI)-enhanced csPWS improved diagnostic performance with AUC=0.90. Considering the low sensitivity of existing CRC tests, including liquid biopsies, to early-stage cancers our work highlights the potential of chromatin biomarkers of field carcinogenesis in detecting early, significant precancerous colon lesions.

Promoter methylation of matrix metallopeptidase 9 in peripheral blood mononuclear cells: A novel biomarker in a promising source for noninvasive colorectal cancer diagnosis

OBJECTIVES

Colorectal cancer (CRC) has been described as a "silent disease," which can be readily treated in most patients when discovered in its early stages. Considering the limitations of the current conventional tests for the diagnosis of CRC, researchers strive to find noninvasive and more valid biomarkers for the early detection of CRC. It has been shown that tumor-specific methylation patterns can also be identified in peripheral blood mononuclear cells (PBMCs) and are reliable sources of methylation analysis for CRC screening.

MATERIALS AND METHODS

We carried out a quantitative methylation analysis on matrix metallopeptidase 9 (MMP9) promoter using methylation quantification endonuclease-resistant DNA (MethyQESD) method. A total of 70 patients with CRC and 70 normal controls were enrolled in this study for methylation analysis in the PBMCs.

RESULTS

Our findings discovered a considerable hypermethylation of MMP9 promoter in CRC patients compared with healthy controls (mean: 47.30% and 20.31%, respectively; P > 0.001). The sensitivity and specificity of the MMP9 gene for the diagnosis of CRC were 88% and 78%, respectively. In addition, on the basis of area under the curve values, the diagnostic power of the MMP9 gene was 0.976 (P < 0.001). Moreover, our analysis established that MMP9 methylation was significantly different between the different stages of CRC (P: 0.034).

CONCLUSIONS

Our results showed that MMP9 promoter methylation in PBMCs can be used as an outstanding biomarker for CRC diagnosis. Besides, we confirmed that PBMCs are reliable sources of methylation analysis for CRC screening and MethyQESD is an accurate and fast method for quantitative methylation analyses.

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.

Cyclin Dependent Kinase Inhibitor 2A Genetic and Epigenetic Alterations Interfere with Several Immune Components and Predict Poor Clinical Outcome

Cyclin dependent kinase inhibitor 2A (CDKN2A) is a well-known tumor suppressor gene as it functions as a cell cycle regulator. While several reports correlate the malfunction of CDKN2A with the initiation and progression of several types of human tumors, there is a lack of a comprehensive study that analyzes the potential effect of CDKN2A genetic alterations on the human immune components and the consequences of that effect on tumor progression and patient survival in a pan-cancer model. The first stage of the current study was the analysis of CDKN2A differential expression in tumor tissues and the corresponding normal ones and correlating that with tumor stage, grade, metastasis, and clinical outcome. Next, a detailed profile of CDKN2A genetic alteration under tumor conditions was described and assessed for its effect on the status of different human immune components. CDKN2A was found to be upregulated in cancerous tissues versus normal ones and that predicted the progression of tumor stage, grade, and metastasis in addition to poor prognosis under different forms of tumors. Additionally, CDKN2A experienced different forms of genetic alteration under tumor conditions, a characteristic that influenced the infiltration and the status of CD8, the chemokine CCL4, and the chemokine receptor CCR6. Collectively, the current study demonstrates the potential employment of CDKN2A genetic alteration as a prognostic and immunological biomarker under several types of human cancers.

Recent Developments in Diagnostic and Prognostic Biomarkers for Colorectal Cancer: A Narrative Review

BACKGROUND

Colorectal cancer was reported as the second most common cause of cancer death worldwide, in the year 2020. This disease is an important public health problem considering its high incidence and mortality rates.

SUMMARY

The molecular events that lead to colorectal cancer include genetic and epigenetic abnormalities. Some of the most important molecular mechanisms involved include the APC/β-catenin pathway, the microsatellite pathway, and the CpG island hypermethylation. Evidence in the literature supports a role for the microbiota in the development of colon carcinogenesis, and specific microbes may contribute to or prevent carcinogenesis. Progress in prevention, screening, and management has improved the overall prognosis of the disease when diagnosed at an early stage; yet metastatic disease continues to have a poor long-term prognosis due to late-stage diagnosis and treatment failure. Biomarkers are a key tool for early detection and prognosis and aim to reduce morbidity and mortality associated with colorectal cancer. The main focus of this narrative review is to provide an update on the recent development of diagnostic and prognostic biomarkers in stool, blood, and tumor tissue samples.

KEY MESSAGES

The review focuses on recent investigations in microRNAs, cadherins, Piwi-interacting RNAs, circulating cell-free DNA, and microbiome biomarkers which can be applied for the diagnosis and prognosis of colorectal cancer.

Non-coding RNAs are correlated to TGF-β receptor type 2 in patients with colorectal cancer

BACKGROUND

Multiple molecular expression alterations, particularly in non-coding RNAs, play fundamental roles in the regulations of cellular processes and may relate to the occurrence and progression of colorectal cancer (CRC). In the present study, we investigated the associations between TGFBR2, miR20a-5p and long non-coding RNA (lncRNA) LAMTOR5-AS1 in CRC patients.

METHODS

Colorectal cancer and adjacent normal tissue samples (n = 34) were prepared from CRC patients. The associations between TGFBR2, miR20a-5p and lncRNA LAMTOR5-AS1 were predicted using bioinformatics tools. The expression levels of TGFBR2, miR20a-5p and lncRNA LAMTOR5-AS1 were measured using a quantitative real-time polymerase chain reaction technique. The TGFBR2 protein values were measured by western blotting. The clinical importance of lncRNA LAMTOR5-AS1 was assessed using receiver operating characteristic curve.

RESULTS

The up-regulated levels of TGFBR2 (p = 0.02), TGFBR2 protein (p = 0.008) and lncRNA LAMTOR5-AS1 (p = 0.02) were significantly observed in CRC tissues compared to the adjacent normal tissues. The miR20a-5p expression level (p = 0.009) was downregulated in CRC tissues. In addition, the miR20a-5p expression level was inversely correlated to the TGFBR2 gene (r²  = 0.88, p < 0.0001), protein (r²  = 0.95, p < 0.0001) and lncRNA LAMTOR5-AS1 gene (r²  = 0.93, p < 0.0001) expression levels. Based on the area under curve, the increase of lncRNA LAMTOR5-AS1 expression level with a sensitivity of 64.52% and specificity of 65.52% was considered in CRC patients.

CONCLUSIONS

We propose that miR20a-5p is inversely related to long non-coding RNA (lncRNA) LAMTOR5-AS, such that it may be involved in the regulation of TGFBR2 expression level in CRC patients.

Hydroxymethylation alterations in progenitor-like cell types of pediatric central nervous system tumors are associated with cell type-specific transcriptional changes

Although intratumoral heterogeneity has been established in pediatric central nervous system tumors, epigenomic alterations at the cell type level have largely remained unresolved. To identify cell type-specific alterations to cytosine modifications in pediatric central nervous system tumors we utilized a multi-omic approach that integrated bulk DNA cytosine modification data (methylation and hydroxymethylation) with both bulk and single-cell RNA-sequencing data. We demonstrate a large reduction in the scope of significantly differentially modified cytosines in tumors when accounting for tumor cell type composition. In the progenitor-like cell types of tumors, we identified a preponderance differential CpG hydroxymethylation rather than methylation. Genes with differential hydroxymethylation, like HDAC4 and IGF1R, were associated with cell type-specific changes in gene expression in tumors. Our results highlight the importance of epigenomic alterations in the progenitor-like cell types and its role in cell type-specific transcriptional regulation in pediatric CNS tumors.

The roles of NOP56 in cancer and SCA36

NOP56 is a highly conserved nucleolar protein. Amplification of the intron GGCCTG hexanucleotide repeat sequence of the NOP56 gene results in spinal cerebellar ataxia type 36 (SCA36). NOP56 contains an N-terminal domain, a coiled-coil domain, and a C-terminal domain. Nucleolar protein NOP56 is significantly abnormally expressed in a number of malignant tumors, and its mechanism is different in different tumors, but its regulatory mechanism in most tumors has not been fully explored. NOP56 promotes tumorigenesis in some cancers and inhibits tumorigenesis in others. In addition, NOP56 is associated with methylation in some tumors, suggesting that NOP56 has the potential to become a tumor-specific marker. This review focuses on the structure, function, related signaling pathways, and role of NOP56 in the progression of various malignancies, and discusses the progression of NOP56 in neurodegenerative and other diseases.

The Importance of the Immune System and Molecular Cell Signaling Pathways in the Pathogenesis and Progression of Lung Cancer

Lung cancer is a disease that in recent years has become one of the greatest threats to modern society. Every year there are more and more new cases and the percentage of deaths caused by this type of cancer increases. Despite many studies, scientists are still looking for answers regarding the mechanisms of lung cancer development and progression, with particular emphasis on the role of the immune system. The aim of this literature review was to present the importance of disorders of the immune system and the accompanying changes at the level of cell signaling in the pathogenesis of lung cancer. The collected results showed that in the process of immunopathogenesis of almost all subtypes of lung cancer, changes in the tumor microenvironment, deregulation of immune checkpoints and abnormalities in cell signaling pathways are involved, which contribute to the multistage and multifaceted carcinogenesis of this type of cancer. We, therefore, suggest that in future studies, researchers should focus on a detailed analysis of tumor microenvironmental immune checkpoints, and to validate their validity, perform genetic polymorphism analyses in a wide range of patients and healthy individuals to determine the genetic susceptibility to lung cancer development. In addition, further research related to the analysis of the tumor microenvironment; immune system disorders, with a particular emphasis on immunological checkpoints and genetic differences may contribute to the development of new personalized therapies that improve the prognosis of patients.

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.

Aberrations of DNA methylation in cancer

DNA methylation is a chromatin modification that plays an important role in the epigenetic regulation of gene expression. Changes in DNA methylation patterns are characteristic of many malignant neoplasms. DNA methylation is occurred by DNA methyltransferases (DNMTs), while demethylation is mediated by TET family proteins. Mutations and changes in the expression profile of these enzymes lead to DNA hypo- and hypermethylation and have a strong impact on carcinogenesis. In this review, we considered the key aspects of the mechanisms of regulation of DNA methylation and demethylation, and also analyzed the role of DNA methyltransferases and TET family proteins in the pathogenesis of various malignant neoplasms.During the preparation of the review, we used the following biomedical literature information bases: Scopus (504), PubMed (553), Web of Science (1568), eLibrary (190). To obtain full-text documents, the electronic resources of PubMed Central (PMC), Science Direct, Research Gate, CyberLeninka were used. To analyze the mutational profile of epigenetic regulatory enzymes, we used the cBioportal portal (https://www.cbioportal.org / ), data from The AACR Project GENIE Consortium (https://www.mycancergenome.org / ), COSMIC, Clinvar, and The Cancer Genome Atlas (TCGA).

Epigenetic Alteration in Colorectal Cancer: A Biomarker for Diagnostic and Therapeutic Application

Colorectal cancer (CRC) is the leading cause of cancer death worldwide. A crucial process that initiates and progresses CRC is various epigenetic and genetic changes occurring in colon epithelial cells. Recently, huge progress has been made to understand cancer epigenetics, especially regarding DNA methylation changes, histone modifications, dysregulation of miRNAs and noncoding RNAs. In the "epigenome" of colon cancer, abnormal methylation of genes that cause gene alterations or expression of miRNA has been reported in nearly all CRC; these findings can be encountered in the average CRC methylome. Epigenetic changes, known as driving events, are assumed to play a dominant part in CRC. Furthermore, as epigenetic changes in CRC become properly understood, these changes are being established as clinical biomarkers for therapeutic and diagnostic purposes. Progression in this area indicates that epigenetic changes will often be utilized in the future to prevent and treat CRC.

Double-stranded RNA induction asa potential dynamic biomarkerfor DNA-demethylating agents

Hypomethylating agents (HMAs), such as azacitidine and decitabine, induce cancer cell death by demethylating DNAs to promote the expression of tumor-suppressor genes. HMAs also reactivate the transcription of endogenous double-stranded RNAs (dsRNAs) that trigger the innate immune response and subsequent apoptosis via viral mimicry. However, the expression patterns of endogenous dsRNAs and their relevance in the efficacy of HMAs remain largely uninvestigated. Here, we employ amidine-conjugated spiropyran (Am-SP) to examine the dynamic expression pattern of total dsRNAs regulated by HMAs. By analyzing the bone-marrow aspirates of myelodysplastic syndrome or acute myeloid leukemia patients who received the HMAs, we find a dramatic increase in total dsRNA levels upon treatment only in patients who later benefited from the therapy. We further apply our approach in solid tumor cell lines and show that the degree of dsRNA induction correlates with the effectiveness of decitabine in most cases. Notably, when dsRNA induction is accompanied by increased expression of nc886 RNA, decitabine becomes ineffective. Collectively, our study establishes the potential application of monitoring the total dsRNA levels by a small molecule as an analytical method and a dynamic marker to predict the clinical outcome of the HMA therapy.

Effects of the Methylation Levels for the Breast Cancer Associated Genes BCSG1 and BRCA1 on Cellular Proliferation and Migration

Objective: The aim of this study was to determine whether the methylation patterns of the breast cancer-specific gene 1 (BCSG1) and the breast cancer susceptibility gene 1 (BRCA1) can be used as biomarkers for predicting the occurrence and development of breast cancer. Methods: Methylation-specific polymerase chain reaction (PCR) was used to detect the methylation status of the BCSG1 and BRCA1 genes in ductal infiltrating carcinomas of the breast; carcinoma in situ of the breast; fibroadenoma of the breast and adjacent normal tissues. Quantitative real-time PCR and immunohistochemistry were used to detect the expression levels of BCSG1 and BRCA1. The BCSG1 and BRCA1 genes were knocked down by siRNA to study their effect of BCSG1 and BRCA1 on the behaviour of breast cancer cell lines. Results: The BCSG1 gene was hypomethylated in breast cancer tissues, and its mRNA as well as its protein levels showed elevated expression compared to normal adjacent tissues. In contrast, the BRCA1 gene was hypermethylated in breast cancer tissues and showed correspondingly decreased mRNA and protein expression levels. In vitro experiments demonstrated that BCSG1 could promote the proliferation and migration of breast cancer cells. After inhibiting the methylation, the expression of both the BCSG1 and BRCA1 genes were increased. Conclusion: Abnormal methylation patterns of the BCSG1 and BRCA1 genes are associated with the development of breast cancer. Thus, methylatedion analyses of these genes have biomarker potential for breast cancer prognoses.

Exercise and colorectal cancer: prevention and molecular mechanisms

Exercise and physical activity have been shown to be strongly associated with a decreased incidence rate of various chronic diseases especially numerous human malignancies. A huge number of clinical trials and meta-analysis have demonstrated that exercise is significantly effective in lowering the risk of colorectal cancer. In addition, it is suggested as an effective therapeutic modality against this cancer type. Therefore, in this review, we will review comprehensibly the effects of exercise in preventing, treating, and alleviating the adverse effects of conventional therapeutic options in colorectal cancer. Moreover, the possible mechanisms underlying the positive effects of exercise and physical activity in colorectal cancer, including regulation of inflammation, apoptosis, growth factor axis, immunity, epigenetic, etc. will be also discussed.

Exercise is an effective post-treatment management program in colorectal cancer survivals

Exercise improves muscle strength, cardiorespiratory fitness, emotional distress, physical activity, fatigue, and sleep quality in colorectal patients undergoing chemotherapy

Targeting and modulating insulin-like growth factor (IGF) system, inflammation, apoptosis, immunity, epigenetic, Leptin and Ghrelin, and signaling pathways are major underlying mechanisms for preventive effects of exercise in colorectal cancer

Epigenetic insights in the diagnosis, prognosis, and treatment selection in CRC, an updated review

BACKGROUND/AIM

The gradual accumulation of genetic and epigenetic alterations can lead to the development of colorectal cancer. In the last decade much research has been done to discover how methylation as an epigenetic alteration leads to carcinogenesis. While Methylation is a biological process, it can influence gene expression by affecting the promoter activity. This article reviews the role of methylation in critical pathways in CRC.

METHODS

In this study using appropriate keywords, all research and review articles related to the role of methylation on different cancers were collected and analyzed. Also, existing information on methylation detection methods and therapeutic sensitivity or resistance due to DNA methylation were reviewed.

RESULTS

The results of this survey revealed that while Methylation is a biological process, it can influence gene expression by affecting the promoter activity. Promoter methylation is associated with up or downregulation of genes involved in critical pathways, including cell cycle, DNA repair, and cell adherence. Hence promoter methylation can be used as a molecular tool for early diagnosis, improving treatment, and predicting treatment resistance.

CONCLUSION

Current knowledge on potential methylation biomarkers for diagnosis and prognoses of CRC has also been discussed. Our survey proposes that a multi-biomarker panel is more efficient than a single biomarker in the early diagnosis of CRC.

Head and neck squamous cell carcinoma: a potential therapeutic target for the Wnt signaling pathway

Squamous cell carcinoma (SCC) of the head and neck region accounts for 3% of all tumors worldwide. The incidence is higher in men, with most carcinomas found in the oral cavity. At the point of initial diagnosis, distant metastases are rare. The Wnt signaling pathway is critically involved in cell development and stemness and has been associated with SCC. Understanding precisely how Wnt signaling regulates SCC progression and how it can, therefore, be modulated for the therapeutic benefit has enormous potential in the treatment of head and neck SCC. In this review, we will describe the underlying mechanisms of Wnt signaling and outline how Wnt signaling controls cellular processes both in homeostasis and in the development and progression of SCC.

Level of evidence: Not gradable.

Obesity-Associated Differentially Methylated Regions in Colon Cancer

Obesity with adiposity is a common disorder in modern days, influenced by environmental factors such as eating and lifestyle habits and affecting the epigenetics of adipose-based gene regulations and metabolic pathways in colorectal cancer (CRC). We compared epigenetic changes of differentially methylated regions (DMR) of genes in colon tissues of 225 colon cancer cases (154 non-obese and 71 obese) and 15 healthy non-obese controls by accessing The Cancer Genome Atlas (TCGA) data. We applied machine-learning-based analytics including generalized regression (GR) as a confirmatory validation model to identify the factors that could contribute to DMRs impacting colon cancer to enhance prediction accuracy. We found that age was a significant predictor in obese cancer patients, both alone (p = 0.003) and interacting with hypomethylated DMRs of ZBTB46, a tumor suppressor gene (p = 0.008). DMRs of three additional genes: HIST1H3I (p = 0.001), an oncogene with a hypomethylated DMR in the promoter region; SRGAP2C (p = 0.006), a tumor suppressor gene with a hypermethylated DMR in the promoter region; and NFATC4 (p = 0.006), an adipocyte differentiating oncogene with a hypermethylated DMR in an intron region, are also significant predictors of cancer in obese patients, independent of age. The genes affected by these DMR could be potential novel biomarkers of colon cancer in obese patients for cancer prevention and progression.

Epigenetic Determinants of Racial Disparity in Breast Cancer: Looking beyond Genetic Alterations

Simple Summary

A substantial disparity in breast cancer incidence and mortality exists between African American (AA) and European American (EA) women. However, the basis for these disparities is poorly understood. In this article, we describe that gene–environment interactions mediated through epigenetic modifications may play a significant role in racial disparities in BC incidence and outcomes. Our in silico analyses and an in-depth literature survey suggest that there exists a significant difference in epigenetic patterns between AA and EA women with breast cancer. Herein, we describe the environmental factors that contribute to these epigenetic changes, which may underlie the disparate racial burden in patients with breast cancer. We suggest that AA women with higher basal epigenetic changes, may have higher pre-disposition to cancer onset, and an aggressive disease course. Pre-existing racial differences in epigenetic profiles of breast tissues raises the possibility of examining these profiles for early diagnosis.

Abstract

Breast cancer (BC) is the most commonly diagnosed cancer in women. Despite advancements in BC screening, prevention, and treatment, BC incidence and mortality remain high among African American (AA) women. Compared with European American (EA) women, AA women tend to be diagnosed with more advanced and aggressive tumors and exhibit worse survival outcomes. Most studies investigating the determinants of racial disparities in BC have focused on genetic factors associated with African ancestry. However, various environmental and social stressors over an individual’s life course can also shape racial stratification in BC. These social and environmental exposures result in long-term changes in gene expression mediated by epigenetic mechanisms. Epigenetics is often portrayed as an intersection of socially patterned stress and genetic expression. The enduring nature of epigenetic changes makes them suitable for studying the effects of different environmental exposures over an individual’s life course on gene expression. The role of differential social and environmental exposures in racial disparities in BC suggests varied epigenetic profiles or signatures associated with specific BC subtypes in AA and EA women. These epigenetic profiles in EA and AA women could be used as biomarkers for early BC diagnosis and disease prognosis and may prove valuable for the development of targeted therapies for BC. This review article discusses the current state of knowledge regarding epigenetic differences between AA and EA women with BC. We also discuss the role of socio-environmental factors, including psychosocial stress, environmental toxicants, and dietary factors, in delineating the different epigenetic profiles in AA and EA patients with BC.

Circular RNA circ_GLIS2 suppresses hepatocellular carcinoma growth and metastasis

BACKGROUND & AIMS

Hepatocellular carcinoma (HCC) is one of the leading causes of tumour-related death. Here, we investigated the molecular mechanism of HCC by studying the function of circ_GLIS2.

METHODS

Human HCC specimens and cell lines were used. Sanger sequencing, actinomycin D and RNase R treatment were performed to validate circular RNA features of circ_GLIS2. qRT-PCR, western blotting, immunostaining, and IHC were employed to examine levels of circ_GLIS2, GLIS2 mRNA, and EMT-related markers. CCK-8, colony formation, flow cytometry, wound healing assay, and transwell assays were performed to evaluate cancer cell proliferation, apoptosis, migration, and invasion. RIP and RNA pull-down assay were used to validate EIF4A3/GLIS2 mRNA interaction. MSP was performed to measure the methylation status of GLIS2 promoter. Nude mouse xenograft model was used to examine tumour growth and metastasis in vivo.

RESULTS

Circ_GLIS2 and linear GLIS2 mRNA were reduced in human HCC tissues and cells. Their low levels correlated with a poor survival rate of HCC patients. Overexpression of circ_GLIS2 and GLIS2 suppressed HCC cell proliferation, migration, and invasion but promoted cell apoptosis. GLIS2 promoter region was hypermethylated in HCC cells. EIF4A3 was directly bound with GLIS2 mRNA and promoted circ_GLIS2/GLIS2 expression. Moreover, overexpression of circ_GLIS2 restrained HCC tumour growth and metastasis in vivo.

CONCLUSION

Circ_GLIS2 suppresses HCC growth and metastasis by inhibiting cell proliferation, migration, and invasion, but promoting cell apoptosis. These findings provide molecular insights into the mechanism of HCC and indicate that circ_GLIS2 could serve as a diagnosis marker or therapeutic target for HCC.

Hypermethylation of PDX1, EN2, and MSX1 predicts the prognosis of colorectal cancer

Despite numerous observations regarding the relationship between DNA methylation changes and cancer progression, only a few genes have been verified as diagnostic biomarkers of colorectal cancer (CRC). To more practically detect methylation changes, we performed targeted bisulfite sequencing. Through co-analysis of RNA-seq, we identified cohort-specific DNA methylation markers: CpG islands of the intragenic regions of PDX1, EN2, and MSX1. We validated that these genes have oncogenic features in CRC and that their expression levels are increased in correlation with the hypermethylation of intragenic regions. The reliable depth of the targeted bisulfite sequencing data enabled us to design highly optimized quantitative methylation-specific PCR primer sets that can successfully detect subtle changes in the methylation levels of candidate regions. Furthermore, these methylation levels can divide CRC patients into two groups denoting good and poor prognoses. In this study, we present a streamlined workflow for screening clinically significant differentially methylated regions. Our discovery of methylation markers in the PDX1, EN2, and MSX1 genes suggests their promising performance as prognostic markers and their clinical application in CRC patients.

An experimental strategy for detecting patterns of DNA modification reveals gene-specific alterations associated with worse outcomes in colorectal cancer patients. Many genomic regions undergo a process of chemical modification called methylation, which can strongly affect the expression of nearby genes. Many cancers exhibit abnormal methylation, and South Korean researchers led by Tae-You Kim of Seoul National University and Lark Kyun Kim of Yonsei University College of Medicine, Seoul, have developed a strategy for identifying such tumor-specific modifications. They identified a trio of genes that undergo excessive methylation in colorectal cancer, and show that this ‘signature’ is associated with more advanced metastatic tumors and shorter overall survival. The results from this study could give clinicians an additional diagnostic tool, and highlight the potential utility of performing such methylation profiling in other cancer types.

Novel Diagnostic Biomarkers in Colorectal Cancer

Colorectal cancer (CRC) is still a leading cause of cancer death worldwide. Less than half of cases are diagnosed when the cancer is locally advanced. CRC is a heterogenous disease associated with a number of genetic or somatic mutations. Diagnostic markers are used for risk stratification and early detection, which might prolong overall survival. Nowadays, the widespread use of semi-invasive endoscopic methods and feacal blood tests characterised by suboptimal accuracy of diagnostic results has led to the detection of cases at later stages. New molecular noninvasive tests based on the detection of CRC alterations seem to be more sensitive and specific then the current methods. Therefore, research aiming at identifying molecular markers, such as DNA, RNA and proteins, would improve survival rates and contribute to the development of personalized medicine. The identification of “ideal” diagnostic biomarkers, having high sensitivity and specificity, being safe, cheap and easy to measure, remains a challenge. The purpose of this review is to discuss recent advances in novel diagnostic biomarkers for tumor tissue, blood and stool samples in CRC patients.

Combined analysis of KARS mutation and p16INK4a and p14ARF methylation status in locally advanced rectal carcinoma treated with preoperative chemoradiotherapy

Current management of locally advanced rectal carcinoma (LARC) involves preoperative chemoradiotherapy (preCRT) before surgery. Despite improved local control rate, the response to preCRT of individual patients is variable and may reflect heterogeneous biological properties among tumors of the same clinical stage. Identifying novel molecular parameters with predictive and/or prognostic value is of great clinical importance for a personalized therapeutic approach. In this study, KRAS mutation status was analyzed by direct sequencing, while methylation-specific polymerase chain reaction (MSP) was used to examine p16INK4a and p14ARF gene methylation status in pretreatment tumor biopsies of 60 patients with LARC. The examined molecular changes of KRAS, p16INK4a and p14ARF genes were mutually independent (p16INK4a/KRAS, P=0.272; p14ARF/KRAS, P=0.923; p16INK4a/p14ARF, P=0.715). However, the simultaneous presence of p14ARF methylation and KRAS mutation was associated with a more frequent appearance of local recurrences and distant metastasis (P=0.027). Moreover, patients with the simultaneous presence of p16INK4a and p14ARF methylation and KRAS mutation had significantly shorter overall survival (P=0.011). The obtained results strongly suggest that combined analyses of examined genetic and epigenetic molecular alterations could contribute to the identification of LARC patient subgroups with more aggressive tumor behavior and worse disease outcome.

Mucosal melanomas of different anatomic sites share a common global DNA methylation profile with cutaneous melanoma but show location-dependent patterns of genetic and epigenetic alterations

Cutaneous, ocular, and mucosal melanomas are histologically indistinguishable tumors that are driven by a different spectrum of genetic alterations. With current methods, identification of the site of origin of a melanoma metastasis is challenging. DNA methylation profiling has shown promise for the identification of the site of tumor origin in various settings. Here we explore the DNA methylation landscape of melanomas from different sites and analyze if different melanoma origins can be distinguished by their epigenetic profile. We performed DNA methylation analysis, next generation DNA panel sequencing, and copy number analysis of 82 non-cutaneous and 25 cutaneous melanoma samples. We further analyzed eight normal melanocyte cell culture preparations. DNA methylation analysis separated uveal melanomas from melanomas of other primary sites. Mucosal, conjunctival, and cutaneous melanomas shared a common global DNA methylation profile. Still, we observed location-dependent DNA methylation differences in cancer-related genes, such as low frequencies of RARB (7/63) and CDKN2A promoter methylation (6/63) in mucosal melanomas, or a high frequency of APC promoter methylation in conjunctival melanomas (6/9). Furthermore, all investigated melanomas of the paranasal sinus showed loss of PTEN expression (9/9), mainly caused by promoter methylation. This was less frequently seen in melanomas of other sites (24/98). Copy number analysis revealed recurrent amplifications in mucosal melanomas, including chromosomes 4q, 5p, 11q and 12q. Most melanomas of the oral cavity showed gains of chromosome 5p with TERT amplification (8/10), while 11q amplifications were enriched in melanomas of the nasal cavity (7/16). In summary, mucosal, conjunctival, and cutaneous melanomas show a surprisingly similar global DNA methylation profile and identification of the site of origin by DNA methylation testing is likely not feasible. Still, our study demonstrates tumor location-dependent differences of promoter methylation frequencies in specific cancer-related genes together with tumor site-specific enrichment for specific chromosomal changes and genetic mutations. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

Coupling of serum CK20 and hyper-methylated CLIP4 as promising biomarker for colorectal cancer diagnosis: from bioinformatics screening to clinical validation

Colorectal cancer (CRC) is one of the most common and lethal malignancies. The identification of minimally invasive and precise biomarkers is an urgent need for the early diagnosis of CRC. Through bioinformatics analysis of 395 CRC tissues and 63 CRC cell lines, CK18, CK20, de-methylated HPDL and hyper-methylated CLIP4 were identified as candidate serum biomarkers. Then, a training cohort consisting of 60 CRC, 30 colorectal adenomas (CA) and 33 healthy controls and a validation cohort consisting of 60 CRC, 30 CA and 30 healthy controls were enrolled. In the training cohort, enzyme-linked immunosorbent assay (ELISA) showed that CK18 and CK20 were all significantly higher in CRC and CA. CK18 diagnosed CRC with 46.67% sensitivity and 87.3% specificity; CK20 diagnosed CRC with 28.33% sensitivity and 90.47% specificity. Methylation-specific PCR (MSP) indicated that de-methylated HPDL and hyper-methylated CLIP4 were significantly detected in CRC and CA. De-methylated HPDL diagnosed CRC with 36.67% sensitivity and 93.65% specificity and hyper-methylated CLIP4 with 73.33% sensitivity and 84.13% specificity. Random combined analysis suggested that CK20/hyper-methylated CLIP4 diagnosed CRC with 91.67% sensitivity and 82.54% specificity. In the validation cohort, CK20 diagnosed CRC with 36.7% sensitivity and 88.3% specificity and hyper-methylated CLIP4 with 80% sensitivity and 85% specificity. CK20/hyper-methylated CLIP4 diagnosed CRC with 95% sensitivity and 81.7% specificity. Compared with serum biomarkers reported before, CK20/hyper-methylated CLIP4 possessed the potential to be a new effective and precise diagnostic biomarker for CRC.

Methylation of FBN1, SPG20, ITF2, RUNX3, SNCA, MLH1, and SEPT9 genes in circulating cell-free DNA as biomarkers of colorectal cancer

BACKGROUND

Investigating aberrant tumor-specific methylation in plasma cell-free DNA provides a promising and noninvasive biomarker for cancer detection.

OBJECTIVE

We aimed to investigate methylation status of some promoter regions in the plasma and tumor tissues to find biomarkers for early detection of colorectal cancer.

METHODS

This case-control study on seventy colorectal cancer patients and fifty matched healthy controls used Methylation-Specific High-Resolution Melting Curve analysis to evaluate the methylation of the selected promoter regions in converted genomic tissue DNA and plasma cfDNA.

RESULTS

The methylation levels in selected regions of SPG20 (+24375 to +24680, +24209 to +24399, and +23625 to +23883), SNCA (+807 to +1013, +7 to +162, and -180 to +7), FBN1 (+223 to +429, +1 to +245, and -18 to -175), ITF2 (+296 to +436 and -180 to +55), SEPT9 (-914412 to -91590 and -99083 to -92264), and MLH1 (-13 to +22) were significantly higher in tumor tissues compared with normal adjacent tissues. The methylation levels of FBN1, ITF2, SNCA, and SPG20 promoters were significantly higher in the patient's plasma compared to patient's normal tissue and plasma of healthy control subjects. FBN1, SPG20, and SEPT9 promoter methylation had a good diagnostic performance for discriminating CRC tissues from normal adjacent tissues (AUC > 0.8). A panel of SPG20, FBN1, and SEPT9 methylation had a higher diagnostic value than that of any single biomarker and other panels in tissue-based assay (AUC > 0.9). The methylation of FBN1(a) and SPG20(a) regions, as the closest region to the first coding sequence (CDS), had a good diagnostic performance in plasma cfDNA (AUC > 0.8) while a panel consisted of FBN1(a) and SPG20(a) regions showed excellent diagnostic performance for CRC detection in plasma cfDNA (AUC > 0.9).

CONCLUSION

Methylation of FBN1(a) and SPG20(a) promoter regions in the plasma cfDNA can be an excellent simple, non-invasive blood-based test for early detection of CRC.

Prognostic role of EGR1 in breast cancer: a systematic review

EGR1 (early growth response 1) is dysregulated in many cancers and exhibits both tumor suppressor and promoter activities, making it an appealing target for cancer therapy. Here, we used a systematic multiomics analysis to review the expression of EGR1 and its role in regulating clinical outcomes in breast cancer (BC). EGR1 expression, its promoter methylation, and protein expression pattern were assessed using various publicly available tools. COSMIC-based somatic mutations and cBioPortal-based copy number alterations were analyzed, and the prognostic roles of EGR1 in BC were determined using Prognoscan and Kaplan-Meier Plotter. We also used bc-GenEx-Miner to investigate the EGR1 co-expression profile. EGR1 was more often downregulated in BC tissues than in normal breast tissue, and its knockdown was positively correlated with poor survival. Low EGR1 expression levels were also associated with increased risk of ER+, PR+, and HER2-BCs. High positive correlations were observed among EGR1, DUSP1, FOS, FOSB, CYR61, and JUN mRNA expression in BC tissue. This systematic review suggested that EGR1 expression may serve as a prognostic marker for BC patients and that clinicopathological parameters influence its prognostic utility. In addition to EGR1, DUSP1, FOS, FOSB, CYR61, and JUN can jointly be considered prognostic indicators for BC.

Combined detection of stool-based methylation indicators for early screening of colorectal neoplasm

In the past two decades, several methylated DNA targets, including gene promoters and other intronic markers have been explored in tumors and benign lesions. Therefore, it can be expected that a panel of stool-based biomarkers will become a screening method for colorectal cancer (CRC) and adenoma with better sensitivity and specificity, aiming to decrease the incidence and mortality of CRC. In this study, the methylation of secreted frizzled-related protein 1 (SFRP1), hyperplastic polyposis protein 1 (HPP1), α-internexin (INA), Wnt inhibitory factor 1 (WIF1), tissue factor pathway inhibitor 2 (TFPI2), ikaros family zinc finger protein 1 (IKZF1), and spastic paraplegia 20 (SPG20) were detected in stool samples from patients with CRC, adenoma, polyps, and healthy controls, respectively, and these biomarkers were used to establish a logistic regression model for classification. Receiver operating characteristic (ROC) curves were drawn to assess the importance of each biomarker. Subsequently, a biomarker or combination of biomarkers was analyzed for early screening of high-risk neoplasm. The data showed that when a single biomarker was used for CRC screening, the sensitivity ranged from 63.9% to 76.8%, the area under the curve (AUC) ranged from 0.821 to 0.875, and the accuracy ranged from 77.0% to 84.5%. Finally, the methylation of SFRP1, HPP1, TFPI2, and IKZF1 was selected using a backward stepwise method in the multivariate logistic analysis according to the Akaike Information Criterion. These findings indicate that stool DNA biomarkers have good diagnostic power in discriminating high-risk level of neoplasm from healthy population.

Global Methylome Scores Correlate with Histological Subtypes of Colorectal Carcinoma and Show Different Associations with Common Clinical and Molecular Features

BACKGROUND

The typical methylation patterns associated with cancer are hypermethylation at gene promoters and global genome hypomethylation. Aberrant CpG island hypermethylation at promoter regions and global genome hypomethylation have not been associated with histological colorectal carcinomas (CRC) subsets. Using Illumina's 450 k Infinium Human Methylation beadchip, the methylome of 82 CRCs were analyzed, comprising different histological subtypes: 40 serrated adenocarcinomas (SAC), 32 conventional carcinomas (CC) and 10 CRCs showing histological and molecular features of microsatellite instability (hmMSI-H), and, additionally, 35 normal adjacent mucosae. Scores reflecting the overall methylation at 250 bp, 1 kb and 2 kb from the transcription starting site (TSS) were studied.

RESULTS

SAC has an intermediate methylation pattern between CC and hmMSI-H for the three genome locations. In addition, the shift from promoter hypermethylation to genomic hypomethylation occurs at a small sequence between 250 bp and 1 Kb from the gene TSS, and an asymmetric distribution of methylation was observed between both sides of the CpG islands (N vs. S shores).

CONCLUSION

These findings show that different histological subtypes of CRC have a particular global methylation pattern depending on sequence distance to TSS and highlight the so far underestimated importance of CpGs aberrantly hypomethylated in the clinical phenotype of CRCs.

Aberrant expression of lncRNAs SNHG6, TRPM2-AS1, MIR4435-2HG, and hypomethylation of TRPM2-AS1 promoter in colorectal cancer

Accumulating evidence has indicated that deregulation of lncRNAs plays essential roles in colorectal cancer (CRC) carcinogenesis. The goal of this study was to analyze the expression of lncRNAs in colorectal cancer and their association with clinicopathological variables. Bioinformatics analysis of published CRC microarray data was performed to identify the important lncRNAs. The expression levels of candidate genes were assessed in the human colon cancer/normal cell lines, CRC, adenomatous colorectal polyps, and their marginal tissues by qRT-PCR. Moreover, the methylation status of the TRPM2-AS1 promoter was studied using qMSP assay. Furthermore, we investigated the molecular mechanisms of these lncRNAs in CRC progression using in silico analysis. Microarray analysis revealed that lncRNAs SNHG6, MIR4435-2HG, and TRPM2-AS1 were upregulated in CRC. These results were validated in colon cell lines. Moreover, qRT-PCR showed that the expression levels of SNHG6 and TRPM2-AS1 were upregulated in the colorectal tumor tissues compared with their paired tissues. Nonetheless, there was no significant increase in MIR4435-2HG expression in CRC samples. Furthermore, we observed a significant hypomethylation of TRPM2-AS1 promoter and its activation in CRC tissues. By in silico analysis, we found that the lncRNAs upregulation could promote proliferation and drug resistance of colorectal cancer cells via miRNAs sponging and modulation of their targets expression. In conclusion, based on our results upregulation of SNHG6 and TRPM2-AS1, and hypomethylation of TRPM2-AS1 promoter might be considered as potential diagnostic biomarkers for CRC initiation and development.

Long noncoding RNA LINC00978 acts as a potential diagnostic biomarker in patients with colorectal cancer

Colorectal cancer (CRC) as a lethal malignancy has been associated with dysregulation of several genes and pathways. Long noncoding RNAs (lncRNAs) play an important role in gene expression regulation. In the current research, we aim to evaluate the expression of LINC00978 in CRC samples and adjacent tissues. Using Quantitative Real-Time PCR (qRT-PCR) method, we assessed the expression levels of LINC00978 and β-catenin in 70 pairs of CRC and adjacent tissues. Moreover, the association between clinicopathological features and the LINC00978 expression levels was investigated. To assess the diagnostic power of LINC00978 expression in CRC, receiver operating characteristic (ROC) curve was plotted. The relationship between LINC00978 and β-catenin expression levels was evaluated using correlation analysis. A markedly increased level of LINC00978 and β-catenin expression levels was observed in CRC samples compared with adjacent tissues (P < 0.0001). No significant association was detected between LINC00978 expression level and the patient's clinicopathological features. The results of Pearson's correlation coefficient highlighted a positive correlation between LINC00978 and β-catenin expression (r² = 0.4695, P < 0.0001). According to the area under curve (AUC) value, LINC00978 expression differentiates CRC samples from the adjacent tissues (AUC = 0.81, P < 0.0001). The present results suggest that LINC00978 may play a critical role in CRC progression via Wnt pathway. The potential role of LINC00978 as a diagnostic biomarker needs to be further investigated in future studies.

Prognostic and clinicopathological insights of phosphodiesterase 9A gene as novel biomarker in human colorectal cancer

BACKGROUND

PDE9A (Phosphodiesterase 9A) plays an important role in proliferation of cells, their differentiation and apoptosis via intracellular cGMP (cyclic guanosine monophosphate) signaling. The expression pattern of PDE9A is associated with diverse tumors and carcinomas. Therefore, PDE9A could be a prospective candidate as a therapeutic target in different types of carcinoma. The study presented here was designed to carry out the prognostic value as a biomarker of PDE9A in Colorectal cancer (CRC). The present study integrated several cancer databases with in-silico techniques to evaluate the cancer prognosis of CRC.

RESULTS

The analyses suggested that the expression of PDE9A was significantly down-regulated in CRC tissues than in normal tissues. Moreover, methylation in the DNA promoter region might also manipulate PDE9A gene expression. The Kaplan-Meier curves indicated that high level of expression of PDE9A gene was associated to higher survival in OS, RFS, and DSS in CRC patients. PDE9A demonstrated the highest positive correlation for rectal cancer recurrence with a marker gene CEACAM7. Furtheremore, PDE9A shared consolidated pathways with MAPK14 to induce survival autophagy in CRC cells and showed interaction with GUCY1A2 to drive CRPC.

CONCLUSIONS

Overall, the prognostic value of PDE9A gene could be used as a potential tumor biomarker for CRC.

Chemokine CXCL14; a double-edged sword in cancer development

Cancer is a leading cause of death worldwide and imposes a substantial financial burden. Therefore, it is essential to develop cost-effective approaches to inhibit tumor growth and development. The imbalance of cytokines and chemokines play an important role among different mechanisms involved in cancer development. One of the strongly conserved chemokines that is constitutively expressed in skin epithelia is the chemokine CXCL14. As a member of the CXC subfamily of chemokines, CXCL14 is responsible for the infiltration of immune cells, maturation of dendritic cells, upregulation of major histocompatibility complex (MHC)-I expression, and cell mobilization. Moreover, dysregulation of CXCL14 in several cancers has been identified by several studies. Depending on the type or origin of the tumor and components of the tumor microenvironment, CXCL14 plays a conflicting role in cancer. Although fibroblast-derived CXCL14 has a tumor-supportive role, epithelial-derived CXCL14 mainly inhibits tumor progression. Hence, this review will elucidate what is known on the mechanisms of CXCL14 and its therapeutic approaches in tumor treatment. CXCL14 is a promising approach for cancer immunotherapy.