Genetic unmasking of an epigenetically silenced microRNA in human cancer cells

Unravelling the epigenetic based mechanism in discovery of anticancer phytomedicine: Evidence based studies

Epigenetic mechanisms play a crucial role in the normal development and maintenance of tissue-specific gene expression patterns in mammals. Disruption of these processes can result in changes to gene function and the transformation of cells into a malignant state. Cancer is characterized by widespread alterations in the epigenetic landscape, revealing that it involves not only genetic mutations but also epigenetic abnormalities. Recent progress in the field of cancer epigenetics has demonstrated significant reprogramming of various components of the epigenetic machinery in cancer, such as DNA methylation, modifications to histones, positioning of nucleosomes, and the expression of non-coding RNAs, particularly microRNAs. The ability to reverse epigenetic abnormalities has given rise to the hopeful field of epigenetic therapy, which has shown advancement with the recent approval by the FDA of three drugs targeting epigenetic mechanisms for the treatment of cancer. In the present manuscript, a comprehensive review has been presented about the role of understanding the epigenetic link between cancer and mechanisms by which phytomedicine offers treatment avenues. Further, this review deciphers the significance of natural products in the identification of epigenetic therapeutics, the diversity of their molecular targets, the use of nanotechnology, and the creation of new strategies for overcoming the inherent clinical challenges associated with developing these drug leads.

Emerging biologic and clinical implications of miR-182-5p in gynecologic cancers

MicroRNAs (miRNAs) have emerged as important regulators of gene expression in various biological processes, including cancer. miR-182-5p has gained attention for its potential implications in gynecologic cancers, including breast, ovarian, endometrial, and cervical cancers. miR-182-5p dysregulation has been associated with multiple facets of tumor biology in gynecologic cancers, including tumor initiation, progression, metastasis, and therapeutic response. Studies have highlighted its involvement in key signaling pathways and cellular processes that contribute to cancer development and progression. In addition, miR-182-5p has shown potential as a diagnostic and prognostic biomarker, with studies demonstrating its correlation with clinicopathological features and patient outcomes. Furthermore, the therapeutic potential of miR-182-5p is being explored in gynecologic cancers. Strategies such as miRNA mimics or inhibitors targeting miR-182-5p have shown promise in preclinical and early clinical studies. These approaches aim to modulate miR-182-5p expression, restoring normal cellular functions and potentially enhancing treatment responses. Understanding the biologic and clinical implications of miR-182-5p in gynecologic cancers is crucial for the development of targeted therapeutic strategies and personalized medicine approaches. Further investigations are needed to unravel the specific target genes and pathways regulated by miR-182-5p. It is important to consider the emerging biologic and clinical implications of miR-182-5p in gynecologic cancers.

Overexpression of miR-23b-3p+miR-218-5p+miR-124-3p differentially modifies the transcriptome of C-33A and CaSki cells and the regulation of cellular processes involved in the progression of cervical cancer

Dysregulation of tumor suppressor miRNAs (tsmiRs) is associated with tumor progression in cancer. miR-23b-3p, miR-218-5p and miR-124-3p are tsmiRs in cervical cancer (CC) and regulate the translation of genes involved in metastasis-related biological processes.

OBJECTIVE

To analyze transcriptome changes in cervical cancer cell lines (C-33A HPV-negative and CaSki HPV-positive) overexpressing miR-23b-3p + miR-218-5p + miR-124-3p, to identify specific target transcripts common to all three miRNAs, as well as signaling pathways and cellular processes related to tumor progression.

METHODS

The transcriptome of C-33A and CaSki cells transfected with miR-23b-3p + miR-218-5p + miR-124-3p was analyzed by RNA-seq. Differentially expressed genes (DEGs) were subjected to Gene Ontology analysis on the DAVID platform. The function of under-regulated genes was analyzed on the GEPIA 2.0, Kaplan-Meier plotter and STRING platforms. On the TargetScanHuman platform it was determined which transcripts have MREs for miR-23b-3p, miR-218-5p and/or miR-124-3p in their 3'UTR region.

RESULTS

Simultaneous overexpression of miR-218-5p, miR-124-3p and miR-23b-3p induced changes in global gene expression in C-33A and CaSki cells. In C-33A cells, DEGs included 45 over- and 172 under-regulated transcripts; in CaSki, 125 transcripts were over- and 84 under-regulated. The under-regulated transcripts enrich proliferation, migration, apoptosis and angiogenesis; 20 of these genes are associated with overall survival (OS) in women with CC, and 18 of the 20 mRNAs have MREs for one, two or all three miRNAs.

CONCLUSIONS

miR-23b-3p + miR-218-5p + miR-124-3p, differentially modify global gene expression in C-33A and CaSki cells. The results indicate that these miRNAs act synergistically and modulate CC progression through individual and shared targets by two or all three miRNAs.

Circulating non-coding RNAs as a tool for liquid biopsy in solid tumors

Solid tumors are significant causes of global mortality and morbidity. Recent research has primarily concentrated on finding pathology-specific molecules that can be acquired non-invasively and that can change as the disease progresses or in response to treatment. The focus of research has moved to RNA molecules that are either freely circulating in body fluids or bundled in microvesicles and exosomes because of their great stability in challenging environments, ease of accessibility, and changes in level in response to therapy. In this context, there are many non-coding RNAs that can be used for this purpose in liquid biopsies. Out of these, microRNAs have been extensively studied. However, there has been an increase of interest in studying long non-coding RNAs, piwi interacting RNAs, circular RNAs, and other small non-coding RNAs. In this article, an overview of the most researched circulating non-coding RNAs in solid tumors will be reviewed, along with a discussion of the significance of these molecules for early diagnosis, prognosis, and therapeutic targets. The publications analyzed were extracted from the PubMed database between 2008 and June 2024.

Methylation-Mediated Silencing of miR-124-3 Regulates LRRC1 Expression and Promotes Oral Cancer Progression

Background: Epigenetic alterations, including DNA methylation, play a crucial role in the development of oral squamous cell carcinoma (OSCC) by regulating the expression of tumor suppressor genes and oncogenes. This study investigated the methylation status of miR-124-3 and its role in OSCC progression. Methods: This study applied the Illumina Infinium MethylationEPIC BeadChip assay to profile >850,000 CpG sites in paired OSCC and normal tissues. The methylation data were validated by further analyzing the methylation level of miR-124-3 by using a bisulfite pyrosequencing assay. We investigated whether miR-124-3 acts as a tumor suppressor by establishing miR-124-3-overexpressing OSCC cells and subjecting them to cell proliferation, colony formation, and migration assays. Dual-luciferase reporter assay was used to validate the target genes of miR-124-3 in OSCC cells. Results: The Infinium MethylationEPIC BeadChip and bisulfite pyrosequencing assays consistently identified hypermethylation of miR-124-3 in OSCC tissues relative to normal oral tissues. It was especially notable that miR-124-3 methylation levels were markedly higher in late-stage tumors than in early-stage, and differed significantly between early-stage tumor and normal tissues, indicating that miR-124-3 methylation is an early event in OSCC development. Methylation of miR-124-3 contributes markedly to the downregulation of the gene, leading to the increased expression of its target gene, leucine-rich repeat-containing 1 (LRRC1), which is considered to be positively associated with cancer progression. Moreover, overexpression of miR-124-3 suppressed the proliferation and migration of OSCC cells, while silencing the expression of LRRC1 produced similar tumor-suppressive effects. Luciferase reporter assays confirmed that miR-124-3 directly targets the 3' untranslated region of LRRC1 to downregulate LRRC1 expression. Conclusions: Hypermethylation-mediated downregulation of miR-124-3 results in increased LRRC1 expression, which drives OSCC progression. These findings highlight DNA methylation of miR-124-3 as a potential biomarker for the early detection of OSCC and a therapeutic target for OSCC treatments.

The role of miRNAs in the pathogenesis, diagnosis, and treatment of colorectal cancer and colitis-associated cancer

MicroRNAs (miRNAs) are a group of noncoding single-stranded RNA biomolecules that act in posttranscriptional regulation of gene expression. Their role in the development of inflammatory bowel disease (IBD), colitis-associated cancer (CAC), and colorectal cancer (CRC) is currently under investigation. A few miRNAs present promising results in terms of diagnostic or therapeutic use, for example, miR-21 increases in CRC and inflammation, while also being a possible target for cancer therapy; miR-301a increases in inflammation but only in patients with IBD; miR-31 increases in CRC, especially in advanced stages, namely III-IV in TNM scale; miR-200 family plays a role in carcinogenesis of CRC and other tumors; examined as a group, miR-31-5p, miR-223-3p, and let-7f-5p trigger and exacerbate CAC; miR-19a could potentially be used in therapy and prevention of both CRC and CAC. Here, we discuss available studies and outline future directions concerning the validity of using miRNAs in the diagnosis and/or therapy of IBD, CAC, and CRC. Extensive research confirms that miRNAs play an important role in the pathogenesis of CAC and CRC. Since the significantly altered expression of certain miRNAs is an early prognostic marker for the development of these diseases, miRNAs have the potential to serve as diagnostic tools, enabling quick and straightforward disease detection.

MicroRNAs in lung cancer: their role in tumor progression, biomarkers, diagnostic, prognostic, and therapeutic relevance

MicroRNAs (miRNAs) are a class of small non-coding RNAs which are associated with post-transcriptional regulation of gene expression. Dysfunction or aberrant expression of miRNAs is predominant in various malignancies including lung cancer. Lung cancer is one of the commonest causes of cancer-related death worldwide, with a five-year survival of only 10-20%. The present review summarizes the current understanding of the role of miRNAs in the development and progression of human lung cancer and their therapeutic potential. Also, we briefly discuss the canonical biogenetic pathway of miRNAs followed by a detailed illustration on how miRNAs regulate human lung cancer progression in various ways. Furthermore, we focus on how miRNAs contribute to the crosstalk between cancer cells and different cells in the tumor microenvironment in the context of lung cancer. Finally, we illustrate how different miRNAs are used as a prognostic and diagnostic biomarker for lung cancer and the ongoing miRNA-associated clinical trials. In conclusion, we discuss how targeting miRNAs can be a potential therapeutic means in the treatment of human lung cancer.

Genetic and epigenetic regulation of non-coding RNAs: Implications in cancer metastasis, stemness and drug resistance

Cancer stem cells (CSCs) have a crucial function in the initiation, advancement, and resistance to therapy of tumors. Recent findings indicate that non-coding RNAs (ncRNAs), such as microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), play a complex role in controlling the features of cancer stem cells (CSCs). Non-coding RNAs (ncRNAs) play a crucial role in controlling important characteristics of stem cells, such as their ability to renew themselves, differentiate into distinct cell types, and resist therapy. This article provides an overview of the current understanding of the complex relationship between non-coding RNAs (ncRNAs), namely microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), and cancer stem cells (CSCs). Particular microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are involved in regulating important signaling pathways like as Wnt, Notch, and Hedgehog, which control stem cell-like characteristics. The miR-34, miR-200, and let-7 families specifically aim at inhibiting the process of self-renewal and epithelial-to-mesenchymal transition. On the other hand, long non-coding RNAs (lncRNAs) such as H19, HOTAIR, and MALAT1 play a role in modifying the epigenetic landscape, hence enhancing the characteristics of stemness. This article also offers a thorough examination of the role of non-coding RNAs (ncRNAs) in regulating cancer stemness, emphasizing their impact on crucial biochemical pathways, epigenetic changes, and therapeutic implications. Comprehending the interaction between non-coding RNAs (ncRNAs) and cancer stem cells (CSCs) provides fresh perspectives on possible focused treatments for fighting aggressive and resistant malignancies. Gaining a comprehensive understanding of the connection between non-coding RNA (ncRNA) and cancer stem cells (CSC) offers valuable insights for the development of novel and precise treatments to combat aggressive cancers that are resistant to conventional therapies. In addition, the combination of ncRNA therapies with conventional methods like as chemotherapy or epigenetic medicines could result in synergistic effects. Nevertheless, there are still obstacles to overcome in terms of delivery, effectiveness, and safety. In summary, the interaction between non-coding RNA and cancer stemness shows potential as a targeted treatment approach in the field of precision oncology. This calls for additional investigation and use in clinical settings.

Epigenetically Regulating Non-coding RNAs in Colorectal Cancer: Promises and Potentials

Colorectal cancer (CRC) is a common malignancy with high mortality. Despite advancements in understanding its molecular causes and improved drug therapies, patient survival rates remain low. The main reasons for the high mortality rate are cancer metastasis and the emergence of drug-resistant cancer cell populations. While genetic changes are recognized as the main driver of CRC occurrence and progression, recent studies suggest that epigenetic regulation is a crucial marker in cancer, influencing the interplay between genetics and the environment. Research has shown the significant regulatory roles of non-coding RNAs (ncRNAs) in CRC development. This review explores epigenetically regulated ncRNAs and their functions, aiming to understand key regulatory mechanisms that impact CRC development. Additionally, it discusses the potential use of these ncRNAs in CRC diagnosis, prognosis, and targeted treatments.

miR-198 targets TOPORS: implications for oral squamous cell carcinoma pathogenesis

Background

miRNAs play a critical role in the progression of various diseases, including oral squamous cell carcinoma (OSCC), which represents a major health concern and is one of the leading causes for new cancer cases worldwide. The miRNA dysregulation causes havoc and could be attributed to various factors, with epigenetic silencing of tumor suppressor genes being a major contributor to tumorigenesis. In this study, we have explored the tumor suppressive role of miR-198 in OSCC.

Methods

The tumor suppressive effect of miR-198 is established using miRNA analysis in OSCC cell lines, patient samples and xenograft nude mice model. The relationship between the miR-198 and TOPORS is explored using bioinformatics analyses, qRT-PCR, dual-luciferase reporter assay, Western blotting and cancer hall marks assays. The hypermethylation of the MIR198 promoter is confirmed using bisulfite sequencing PCR.

Results

We have found miR-198 to be upregulated in OSCC cells treated with 5-Azacytidine, a known DNA methyltransferase inhibitor. Upregulation of miR-198 in 5-Azacytidine treated OSCC cells appears to be due to methylation of the MIR198 promoter. Using bioinformatics analysis and dual-luciferase reporter assay, we have identified TOPORS (TOP1 binding arginine/serine rich protein, E3 ubiquitin ligase) as a novel gene target for miR-198. miR-198-mediated repression of TOPORS decreases cell proliferation and anchorage-independent growth and enhances apoptosis of OSCC cells, which is dependent on the presence of the 3'UTR in TOPORS. An inverse correlation between the expression levels of miR-198 and TOPORS is observed in OSCC patient samples, highlighting the biological relevance of their interaction. Delivery of a synthetic miR-198 mimic to OSCC cells results in a significant decrease in xenograft size in nude mice, potentiating its use in therapeutics.

Conclusions

These results suggest that miR-198 is epigenetically silenced in OSCC, which promotes tumor growth, in part, by upregulating the levels of TOPORS.

MicroRNAs as Promising Therapeutic Agents Against Prostate Cancer Resistant to Castration-Where Are We Now?

MicroRNAs are a conserved class of small, tissue-specific, non-coding RNAs that regulate gene expression to preserve cellular homeostasis. Proper miRNA expression is crucial for physiological balance because it affects numerous genetic pathways, including cell cycle control, proliferation, and apoptosis, through gene expression targeting. Deregulated miRNA expression has been implicated in several cancer types, including prostate cancer (PC), acting as tumor suppressors or oncogenes. Despite the availability of promising therapies to control tumor growth and progression, effective diagnostic and therapeutic strategies for different types of cancer are still lacking. PC continues to be a significant health challenge, particularly its castration-resistant (CRPC) form, which presents major therapeutic obstacles because of its resistance to conventional androgen deprivation treatments. This review explores miRNAs' critical roles in gene regulation and cancer biology, as well as various miRNA delivery systems, highlighting their potential and the challenges in effectively targeting cancer cells. It aims to provide a comprehensive overview of the status of miRNA research in the fight against CRPC, summarizing miRNA-based therapies' successes and limitations. It also highlights the promise of miRNAs as therapeutic agents for CRPC, underlining the need for further research to overcome existing challenges and move these therapies toward clinical applications.

The Epigenetic Hallmarks of Cancer

Cancer is a complex disease in which several molecular and cellular pathways converge to foster the tumoral phenotype. Notably, in the latest iteration of the cancer hallmarks, "nonmutational epigenetic reprogramming" was newly added. However, epigenetics, much like genetics, is a broad scientific area that deserves further attention due to its multiple roles in cancer initiation, progression, and adaptive nature. Herein, we present a detailed examination of the epigenetic hallmarks affected in human cancer, elucidating the pathways and genes involved, and dissecting the disrupted landscapes for DNA methylation, histone modifications, and chromatin architecture that define the disease. Significance: Cancer is a disease characterized by constant evolution, spanning from its initial premalignant stages to the advanced invasive and disseminated stages. It is a pathology that is able to adapt and survive amidst hostile cellular microenvironments and diverse treatments implemented by medical professionals. The more fixed setup of the genetic structure cannot fully provide transformed cells with the tools to survive but the rapid and plastic nature of epigenetic changes is ready for the task. This review summarizes the epigenetic hallmarks that define the ecological success of cancer cells in our bodies.

Cortisol affects macrophage polarization by inducing miR-143/145 cluster to reprogram glucose metabolism and by promoting TCA cycle anaplerosis

Chronic stress can have adverse consequences on human health by disrupting the hormonal balance in our body. Earlier, we observed elevated levels of cortisol, a primary stress hormone, and some exosomal microRNAs in the serum of patients with breast cancer. Here, we investigated the role of cortisol in microRNA induction and its functional consequences. We found that cortisol induced the expression of miR-143/145 cluster in human monocyte (THP1 and U937)-derived macrophages but not in breast cancer cells. In silico analysis identified glucocorticoid-response element in the upstream CARMN promoter utilized by the miR-143/145 cluster. Enhanced binding of glucocorticoid-receptor (GR) upon cortisol exposure and its regulatory significance was confirmed by chromatin-immunoprecipitation and promoter-reporter assays. Further, cortisol inhibited IFNγ-induced M1 polarization and promoted M2 polarization, and these effects were suppressed by miR-143-3p and miR-145-5p inhibitors pretreatment. Cortisol-treated macrophages exhibited increased oxygen-consumption rate (OCR) to extracellular-acidification rate (ECAR) ratio, and this change was neutralized by functional inhibition of miR-143-3p and miR-145-5p. HK2 and ADPGK were confirmed as the direct targets of miR-143-3p and miR-145-5p, respectively. Interestingly, silencing of HK2 and ADPGK inhibited IFNγ-induced M1 polarization but failed to induce M2 polarization, since it suppressed both ECAR and OCR, while OCR was largely sustained in cortisol-treated M2-polarized macrophages. We found that cortisol treatment sustained OCR by enhancing fatty acid and glutamine metabolism through upregulation of CPT2 and GLS, respectively, to support M2 polarization. Thus, our findings unfold a novel mechanism of immune suppression by cortisol and open avenues for preventive and therapeutic interventions.

Research trend of lung cancer epigenetics research: Bibliometric and visual analysis of top-100 cited documents

Background

Lung cancer is a highly prevalent cancer on a global scale and its oncogenic process is driven by the accumulation of multiple pathological events. Epigenetics has gained significant recognition in recent years as a crucial contributor to the development of lung cancer. Epigenetics include processes such as DNA methylation, histone modification, chromatin remodeling, and RNA modification. These pathways lead to enduring alterations in genetic phenotypes, which are crucial in the advancement and growth of lung cancer. However, the specific mechanisms and roles of epigenetics in lung cancer still need to be further elucidated.

Methods

We obtained publications from the Web of Science databases and applied a rigorous search method to filter them. Ultimately, we gathered high-quality publications that had received the highest 100 number of citations. The data were processed and visualized by various bibliometric tools.

Results

The 100 papers had varying numbers of citations, with the lowest being 491 and the most being 6316. On average, each work received 1119 citations. A total of 1056 co-authors were involved in publishing these papers in 59 journals from 185 institutions in 27 countries. The majority of high-caliber research in the subject of lung cancer epigenetics is conducted in advanced countries, with the United States taking the lead in terms of both the quantity of articles produced and their academic influence. The study of DNA methylation has been a longstanding research priority in the discipline. With the development of next-generation sequencing technology in recent years, research related to non-coding RNA has become a research hotspot. Future research directions may focus more on exploring the mechanisms of action of messenger RNA and circular RNA and developing targeted treatment strategies based on non-coding RNA drugs.

Conclusion

We analyzed 100 top lung cancer and epigenetics documents through various bibliometric analysis tools. This study provides a concise overview of the findings from prior research, anticipates future research directions, and offers potential avenues for additional investigation.

Non-coding RNAs as therapeutic targets in cancer and its clinical application

Cancer genomics has led to the discovery of numerous oncogenes and tumor suppressor genes that play critical roles in cancer development and progression. Oncogenes promote cell growth and proliferation, whereas tumor suppressor genes inhibit cell growth and division. The dysregulation of these genes can lead to the development of cancer. Recent studies have focused on non-coding RNAs (ncRNAs), including circular RNA (circRNA), long non-coding RNA (lncRNA), and microRNA (miRNA), as therapeutic targets for cancer. In this article, we discuss the oncogenes and tumor suppressor genes of ncRNAs associated with different types of cancer and their potential as therapeutic targets. Here, we highlight the mechanisms of action of these genes and their clinical applications in cancer treatment. Understanding the molecular mechanisms underlying cancer development and identifying specific therapeutic targets are essential steps towards the development of effective cancer treatments.

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

BACKGROUND

Epigenetic biomarkers in cancer have emerged as promising tools for early detection, prognosis, and treatment response prediction. In cervical cells, hypermethylation of the host and viral HPV-genome increases with the severity of lesions, providing a useful biomarker in the triage of hr-HPV-positive women and during treatment. The present study focuses on evaluating the clinical performance of the FAM19A4/miR124-2 methylation test in a population-based cervical screening program.

METHODS

Previously collected cervical samples, after bisulfite-converted DNA, were analyzed by PreCursor-M+ kit (distributed by Fujirebio Europe), for DNA methylation. The sensitivity, specificity, and negative/positive predictive values of DNA methylation were compared to histology, colposcopy, the HPV-DNA test, and cytology results.

RESULTS

Among the 61-sample set, the specificity of methylation vs. positive histology (≥CIN2) and colposcopy (≥G2) were 87% and 90%, whereas the sensitivity was 50% and 33.3%, respectively. The combination of methylation analysis with standard methods increases diagnostic accuracy.

CONCLUSIONS

Overall, we found a good specificity of DNA methylation in comparison to currently used techniques. Further larger studies could support the use of FAM19A4/miR124-2 as reliable biomarkers in the prevention of cervical cancer as triage in the screening protocol.

Promoter methylation levels of microRNA-124 in non-neoplastic rectal mucosa as a potential biomarker for ulcerative colitis-associated colorectal cancer in pediatric-onset patients

PURPOSE

To determine the methylation level of the miR-124 promoter in non-neoplastic rectal mucosa of patients with pediatric-onset ulcerative colitis (UC) to predict UC-associated colorectal cancer (UC-CRC).

METHODS

Between 2005 and 2017, non-neoplastic rectal tissue specimens were collected from 86 patients with UC, including 13 patients with UC-CRC; cancer tissues were obtained from the latter group. The methylation status of the miR-124 promoter was quantified using bisulfite pyrosequencing and compared between pediatric- and adult-onset UC patients.

RESULTS

Patients with pediatric-onset UC experienced a significantly shorter disease duration than those with adult-onset UC. The levels of miR-124 promoter methylation in non-neoplastic rectal mucosa were positively correlated with the age at the diagnosis and duration of UC. The rate of increase in miR-124 methylation was accelerated in patients with pediatric-onset UC compared to those with adult-onset UC. Furthermore, the miR-124 methylation levels in non-neoplastic rectal mucosa were significantly higher in patients with UC-CRC than in those with UC alone (P = 0.02). A receiver operating characteristic analysis revealed that miR-124 methylation in non-neoplastic tissue discriminated between patients with pediatric-onset UC with or without CRC.

CONCLUSION

miR-124 methylation in non-neoplastic rectal mucosa may be a useful biomarker for identifying patients with pediatric-onset UC who face the highest risk of developing UC-CRC.

Trials and Tribulations of MicroRNA Therapeutics

The discovery of the link between microRNAs (miRNAs) and a myriad of human diseases, particularly various cancer types, has generated significant interest in exploring their potential as a novel class of drugs. This has led to substantial investments in interdisciplinary research fields such as biology, chemistry, and medical science for the development of miRNA-based therapies. Furthermore, the recent global success of SARS-CoV-2 mRNA vaccines against the COVID-19 pandemic has further revitalized interest in RNA-based immunotherapies, including miRNA-based approaches to cancer treatment. Consequently, RNA therapeutics have emerged as highly adaptable and modular options for cancer therapy. Moreover, advancements in RNA chemistry and delivery methods have been pivotal in shaping the landscape of RNA-based immunotherapy, including miRNA-based approaches. Consequently, the biotechnology and pharmaceutical industry has witnessed a resurgence of interest in incorporating RNA-based immunotherapies and miRNA therapeutics into their development programs. Despite substantial progress in preclinical research, the field of miRNA-based therapeutics remains in its early stages, with only a few progressing to clinical development, none reaching phase III clinical trials or being approved by the US Food and Drug Administration (FDA), and several facing termination due to toxicity issues. These setbacks highlight existing challenges that must be addressed for the broad clinical application of miRNA-based therapeutics. Key challenges include establishing miRNA sensitivity, specificity, and selectivity towards their intended targets, mitigating immunogenic reactions and off-target effects, developing enhanced methods for targeted delivery, and determining optimal dosing for therapeutic efficacy while minimizing side effects. Additionally, the limited understanding of the precise functions of miRNAs limits their clinical utilization. Moreover, for miRNAs to be viable for cancer treatment, they must be technically and economically feasible for the widespread adoption of RNA therapies. As a result, a thorough risk evaluation of miRNA therapeutics is crucial to minimize off-target effects, prevent overdosing, and address various other issues. Nevertheless, the therapeutic potential of miRNAs for various diseases is evident, and future investigations are essential to determine their applicability in clinical settings.

Cancer epigenetics: from laboratory studies and clinical trials to precision medicine

Epigenetic dysregulation is a common feature of a myriad of human diseases, particularly cancer. Defining the epigenetic defects associated with malignant tumors has become a focus of cancer research resulting in the gradual elucidation of cancer cell epigenetic regulation. In fact, most stages of tumor progression, including tumorigenesis, promotion, progression, and recurrence are accompanied by epigenetic alterations, some of which can be reversed by epigenetic drugs. The main objective of epigenetic therapy in the era of personalized precision medicine is to detect cancer biomarkers to improve risk assessment, diagnosis, and targeted treatment interventions. Rapid technological advancements streamlining the characterization of molecular epigenetic changes associated with cancers have propelled epigenetic drug research and development. This review summarizes the main mechanisms of epigenetic dysregulation and discusses past and present examples of epigenetic inhibitors in cancer diagnosis and treatment, with an emphasis on the development of epigenetic enzyme inhibitors or drugs. In the final part, the prospect of precise diagnosis and treatment is considered based on a better understanding of epigenetic abnormalities in cancer.

Drug repurposing: A novel strategy to target cancer stem cells and therapeutic resistance

Chemotherapy is an effortless and frequently used approach in cancer therapy. However, in most cases, it can only prolong life expectancy and does not guarantee a complete cure. Furthermore, chemotherapy is associated with severe adverse effects, one of the major complications of effective cancer therapy. In addition, newly published research outputs show that cancer stem cells are involved in cancer disease progression, drug resistance, metastasis, and recurrence and that they are functional in the trans-differentiation capacity of cancer stem cells to cancer cells in response to treatments. Novel strategies are therefore required for better management of cancer therapy. The prime approach would be to synthesize and develop novel drugs that need extensive resources, time, and endurance to be brought into therapeutic use. The subsequent approach would be to screen the anti-cancer activity of available non-cancerous drugs. This concept of repurposing non-cancer drugs as an alternative to current cancer therapy has become popular in recent years because using existing anticancer drugs has several adverse effects. Micronutrients have also been investigated for cancer therapy due to their significant anti-cancer effects with negligible or no side effects and availability in food sources. In this paper, we discuss an ideal hypothesis for screening available non-cancerous drugs with anticancer activity, with a focus on cancer stem cells and their clinical application for cancer treatment. Further, drug repurposing and the combination of micronutrients that can target both cancers and cancer stem cells may result in a better therapeutic approach leading to maximum tumor growth control.

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.

Domestic Animal Models of Central Nervous System Tumors: Focus on Meningiomas

Intracranial primary tumors (IPTs) are aggressive forms of malignancies that cause high mortality in both humans and domestic animals. Meningiomas are frequent adult IPTs in humans, dogs, and cats, and both benign and malignant forms cause a decrease in life quality and survival. Surgery is the primary therapeutic approach to treat meningiomas, but, in many cases, it is not resolutive. The chemotherapy and targeted therapy used to treat meningiomas also display low efficacy and many side effects. Therefore, it is essential to find novel pharmacological approaches to increase the spectrum of therapeutic options for meningiomas. This review analyzes the similarities between human and domestic animal (dogs and cats) meningiomas by evaluating the molecular and histological characteristics, diagnosis criteria, and treatment options and highlighting possible research areas to identify novel targets and pharmacological approaches, which are useful for the diagnosis and therapy of this neoplasia to be used in human and veterinary medicine.

Regulation of microRNA by circular RNA

Circular (circ)RNAs have emerged as novel regulators of gene expression through various mechanisms. However, most publications focus on functional circRNAs regulating target gene expression by interacting with micro (mi)RNAs and acting as competing endogenous RNAs (ceRNAs). Although the theory of miRNA sponging by ceRNAs suggests the inhibition of miRNA activity, many studies are biased toward the selection of miRNAs showing a reverse expression pattern compared with circRNA expression. Although several computational tools and molecular assays have been used to predict and validate the interaction of miRNAs with circRNAs, the actual validation of functional in vivo interactions needs careful consideration of molecular experiments with specific controls. As extensive research is being performed on circRNA, many questions arise on the functional significance of circRNA-miRNA interactions. We hope the critical discussion on the criteria for selecting circRNA-miRNA pairs for functional analysis and providing standard methods for validating circRNA-miRNA interactions will advance our understanding of circRNAs as novel gene regulators. This article is categorized under: Regulatory RNAs/RNAi/Riboswitches > Regulatory RNAs Translation > Regulation RNA Methods > RNA Analyses in Cells.

Differential functions of RhoGDIβ in malignant transformation and progression of urothelial cell following N-butyl-N-(4-hydmoxybutyl) nitrosamine exposure

BACKGROUND

Functional role of Rho GDP-dissociation inhibitor beta (RhoGDIβ) in tumor biology appears to be contradictory across various studies. Thus, the exploration of the molecular mechanisms underlying the differential functions of this protein in urinary bladder carcinogenesis is highly significant in the field. Here, RhoGDIβ expression patterns, biological functions, and mechanisms leading to transformation and progression of human urothelial cells (UROtsa cells) were evaluated following varying lengths of exposure to the bladder carcinogen N-butyl-N-(4-hydmoxybutyl) nitrosamine (BBN).

RESULTS

It was seen that compared to expression in vehicle-treated control cells, RhoGDIβ protein expression was downregulated after 2-month of BBN exposure, but upregulated after 6-month of exposure. Assessments of cell function showed that RhoGDIβ inhibited UROtsa cell growth in cells with BBN for 2-month exposure, whereas it promoted the invasion of cells treated with BBN for 6 months. Mechanistic studies revealed that 2-month of BBN exposure markedly attenuated DNMT3a abundance, and this led to reduced miR-219a promoter methylation, increased miR-219a binding to the RhoGDIβ mRNA 3'UTR, and reduced RhoGDIβ protein translation. While after 6-mo of BBN treatment, the cells showed increased PP2A/JNK/C-Jun axis phosphorylation and this in turn mediated overall RhoGDIβ mRNA transcription and protein expression as well as invasion.

CONCLUSIONS

These findings indicate that RhoGDIβ is likely to inhibit the transformation of human urothelial cells during the early phase of BBN exposure, whereas it promotes invasion of the transformed/progressed urothelial cells in the late stage of BBN exposure. The studies also suggest that RhoGDIβ may be a useful biomarker for evaluating the progression of human bladder cancers.

Bibliometric and visualized analysis of applying tumor markers in lung cancer diagnosis from 2000 to 2022

Background

Lung cancer (LC) is the leading cause of cancer-related deaths worldwide. Tumor marker (TM) detection can indicate the existence and growth of a tumor and has therefore been used extensively for diagnosing LC. Here, we conducted a bibliometric analysis to examine TM-related publications for LC diagnosis to illustrate the current state and future trends of this field, as well as to identify additional promising TMs with high sensitivity.

Methods

Publications regarding TMs in LC diagnosis were downloaded from the Web of Science Core Collection. CiteSpace was applied to perform a bibliometric analysis of journals, cocitation authors, keywords, and references related to this field. VOSviewer was used to generate concise diagrams about countries, institutions, authors, and keywords. Changes in the TM research frontier were analyzed through citation burst detection.

Results

A total of 990 studies were analyzed in this work. The collaboration network analysis revealed that the People's Republic of China, Yonsei University, and Molina R were the most productive country, institution, and scholar, respectively. Additionally, Molina R was the author with the most citations. The National Natural Science Foundation of China was the largest funding source. "Carcinoembryonic antigen (CEA) as tumor marker in lung cancer" was the top reference with the most citations, Lung Cancer was the core journal, and "serum tumor marker" experienced a citation burst over the past 5 years.

Conclusion

This bibliometric analysis of TMs in LC diagnosis presents the current trends and frontiers in this field. We summarized the research status of this field and the methods to improve the diagnostic efficacy of traditional serum TMs, as well as provided new directions and ideas for improving the LC clinical detection rate. Priority should be given to the transformation of computer-assisted diagnostic technology for clinical applications. In addition, circulating tumor cells, exosomes, and microRNAs were the current most cutting-edge TMs.

Crosstalk between miRNAs and DNA Methylation in Cancer

miRNAs are some of the most well-characterized regulators of gene expression. Integral to several physiological processes, their aberrant expression often drives the pathogenesis of both benign and malignant diseases. Similarly, DNA methylation represents an epigenetic modification influencing transcription and playing a critical role in silencing numerous genes. The silencing of tumor suppressor genes through DNA methylation has been reported in many types of cancer and is associated with tumor development and progression. A growing body of literature has described the crosstalk between DNA methylation and miRNAs as an additional layer in the regulation of gene expression. Methylation in miRNA promoter regions inhibits its transcription, while miRNAs can target transcripts and subsequently regulate the proteins responsible for DNA methylation. Such relationships between miRNA and DNA methylation serve an important regulatory role in several tumor types and highlight a novel avenue for potential therapeutic targets. In this review, we discuss the crosstalk between DNA methylation and miRNA expression in the pathogenesis of cancer and describe how miRNAs influence DNA methylation and, conversely, how methylation impacts the expression of miRNAs. Finally, we address how these epigenetic modifications may be leveraged as biomarkers in cancer.

The role of noncoding RNAs in metabolic reprogramming of cancer cells

Metabolic reprogramming is a well-known feature of cancer that allows malignant cells to alter metabolic reactions and nutrient uptake, thereby promoting tumor growth and spread. It has been discovered that noncoding RNAs (ncRNAs), including microRNA (miRNA), long noncoding RNA (lncRNA), and circular RNA (circRNA), have a role in a variety of biological functions, control physiologic and developmental processes, and even influence disease. They have been recognized in numerous cancer types as tumor suppressors and oncogenic agents. The role of ncRNAs in the metabolic reprogramming of cancer cells has recently been noticed. We examine this subject, with an emphasis on the metabolism of glucose, lipids, and amino acids, and highlight the therapeutic use of targeting ncRNAs in cancer treatment.

Unraveling the Post-Translational Modifications and therapeutical approach in NSCLC pathogenesis

Non-Small Cell Lung Cancer (NSCLC) is the most prevalent kind of lung cancer with around 85% of total lung cancer cases. Despite vast therapies being available, the survival rate is low (5 year survival rate is 15%) making it essential to comprehend the mechanism for NSCLC cell survival and progression. The plethora of evidences suggests that the Post Translational Modification (PTM) such as phosphorylation, methylation, acetylation, glycosylation, ubiquitination and SUMOylation are involved in various types of cancer progression and metastasis including NSCLC. Indeed, an in-depth understanding of PTM associated with NSCLC biology will provide novel therapeutic targets and insight into the current sophisticated therapeutic paradigm. Herein, we reviewed the key PTMs, epigenetic modulation, PTMs crosstalk along with proteogenomics to analyze PTMs in NSCLC and also, highlighted how epi‑miRNA, miRNA and PTM inhibitors are key modulators and serve as promising therapeutics.

Crosstalk between epigenetics and tumor promoting androgen signaling in prostate cancer

Prostate cancer (PCa) is one of the major health burdens among all cancer types in men globally. Early diagnosis and efficacious treatment options are highly warranted as far as the incidence of PCa is concerned. Androgen-dependent transcriptional activation of androgen receptor (AR) is central to the prostate tumorigenesis and therefore hormonal ablation therapy remains the first line of treatment for PCa in the clinics. However, the molecular signaling engaged in AR-dependent PCa initiation and progression is infrequent and diverse. Moreover, apart from the genomic changes, non-genomic changes such as epigenetic modifications have also been suggested as critical regulator of PCa development. Among the non-genomic mechanisms, various epigenetic changes such as histones modifications, chromatin methylation and noncoding RNAs regulations etc. play decisive role in the prostate tumorigenesis. Given that epigenetic modifications are reversible using pharmacological modifiers, various promising therapeutic approaches have been designed for the better management of PCa. In this chapter, we discuss the epigenetic control of tumor promoting AR signaling that underlies the mechanism of prostate tumorigenesis and progression. In addition, we have discussed the approaches and opportunities to develop novel epigenetic modifications based therapeutic strategies for targeting PCa including castrate resistant prostate cancer (CRPC).

Epigenetic Abnormalities in Chondrosarcoma

In recent years, our understanding of the epigenetic mechanisms involved in tumor pathology has improved greatly. DNA and histone modifications, such as methylation, demethylation, acetylation, and deacetylation, can lead to the up-regulation of oncogenic genes, as well as the suppression of tumor suppressor genes. Gene expression can also be modified on a post-transcriptional level by microRNAs that contribute to carcinogenesis. The role of these modifications has been already described in many tumors, e.g., colorectal, breast, and prostate cancers. These mechanisms have also begun to be investigated in less common tumors, such as sarcomas. Chondrosarcoma (CS) is a rare type of tumor that belongs to sarcomas and is the second most common malignant bone tumor after osteosarcoma. Due to unknown pathogenesis and resistance to chemo- and radiotherapies of these tumors, there is a need to develop new potential therapies against CS. In this review, we summarize current knowledge on the influence of epigenetic alterations in the pathogenesis of CS by discussing potential candidates for future therapies. We also emphasize ongoing clinical trials that use drugs targeting epigenetic modifications in CS treatment.

Long non-coding RNAs: an overview on miRNA sponging and its co-regulation in lung cancer

Lung cancer is the most devastating cause of death among all cancers worldwide, and non-small cell lung cancer (NSCLC) accounts for 80% of all the lung cancer cases. Beyond common genetic research and epigenomic studies, the extraordinary investigations of non-coding RNAs have provided insights into the molecular basis of cancer. Existing evidence from various cancer models highlights that the regulation of non-coding RNAs is crucial and that their deregulation may be a common reason for the development and progression of cancer, and competition of cancer therapeutics. Non-coding RNAs, such as long non-coding RNAs (lncRNAs) and microRNAs (miRNAs), are increasingly recognized as potential cancer biomarkers for early detection and application of therapeutic strategies. The miRNAs have gained importance as master regulators of target mRNAs by negatively regulating their expression. The lncRNAs function as both tumor suppressors and oncogenes, and also compete with miRNAs that influence the translational inhibition processes. This review addresses the role of lncRNAs in lung cancer development, highlights their mechanisms of action, and provides an overview of the impact of lncRNAs on lung cancer survival and progression via miRNA sponging. The improved understanding of lung cancer mechanisms has opened opportunities to analyze molecular markers and their potential therapeutics.

MicroRNAs as clinical tools for diagnosis, prognosis, and therapy in prostate cancer

Prostate cancer (PCa) is one of the most commonly diagnosed cancers among men worldwide. Despite the presence of accumulated clinical strategies for PCa management, limited prognostic/sensitive biomarkers are available to follow up on disease occurrence and progression. MicroRNAs (miRNAs) are small non-coding RNAs that control gene expression through post-transcriptional regulation of their complementary target messenger RNA (mRNA). MiRNAs modulate fundamental biological processes and play crucial roles in the pathology of various diseases, including PCa. Multiple evidence proved an aberrant miRNA expression profile in PCa, which is actively involved in the carcinogenic process. The robust and pleiotropic impact of miRNAs on PCa suggests them as potential candidates to help more understand the molecular landscape of the disease, which is likely to provide tools for early diagnosis and prognosis as well as additional therapeutic strategies to manage prostate tumors. Here, we emphasize the most consistently reported dysregulated miRNAs and highlight the contribution of their altered downstream targets with PCa hallmarks. Also, we report the potential effectiveness of using miRNAs as diagnostic/prognostic biomarkers in PCa and the high-throughput profiling technologies that are being used in their detection. Another key aspect to be discussed in this review is the promising implication of miRNAs molecules as therapeutic tools and targets for fighting PCa.

Quercetin up-regulates the expression of tumor-suppressive microRNAs in human cervical cancer

Quercetin, a flavonol present in many vegetables and fruits, has been identified as a chemoprevention agent in several cancer models. However, the molecular mechanism of quercetin's anticancer activity is not entirely understood. MicroRNAs (miRNAs), small noncoding RNAs, have been reported to play key roles in various biological processes by regulating their target genes. We hypothesized that quercetin can exert an anticancer effect through the regulation of miRNAs. To test this hypothesis, we investigated the effects of quercetin on the expression of tumor-suppressive miRNAs in cervical cancer. Quercetin up-regulated the in vivo and in vitro expression of tumor-suppressive miRNAs miR-26b, miR-126, and miR-320a. Quercetin suppressed the level of β-catenin, encoded by catenin beta 1 (CTNNB1), by up-regulating miR-320a in HeLa cells. Moreover, quercetin increased the expression of mir-26b, mir-126, and mir-320a precursors in HeLa cells. The results from this study show that quercetin has the potential to prevent cervical cancer by regulating the expression of tumor-suppressive miRNAs.

Insight into epigenetics and human diseases

The most eminent research of the 21st century whirls around the epigenetic and the variability of DNA sequences in humans. The reciprocity between the epigenetic changes and the exogenous factors drives an influence on the inheritance biology and gene expression both inter-generationally and trans-generationally. Chromatin level modifications like DNA methylation, histone modifications or changes in transcripts functions either at transcription level or translational level pave the way for certain diseases or cancer in humans. The ability of epigenetics to explain the processes of various diseases has been demonstrated by recent epigenetic studies. Multidisciplinary therapeutic strategies were developed in order to analyse how epigenetic elements interact with different disease pathways. In this chapter we summarize how an organism may be predisposed to certain diseases by exposure to environmental variables such as chemicals, medications, stress, or infections during particular, vulnerable phases of life, and the epigenetic component may influence some of the diseases in humans.

Aberrant methylation of miR-124 upregulates DNMT3B in colorectal cancer to accelerate invasion and migration

The dysregulation of microRNA expression is significantly associated with the initiation and development of CRC. miR-124 is markedly downregulated in colorectal cancer. In the present study, the effects of methylation, over expression and downregulation of miR-124 and its target gene DNMT3B on the proliferation, migration and invasion of colorectal cell line were investigated. The promoter methylation status of miR-124 in the CRC was investigated by methylation specific PCR (MSP). The potential role of miR-124 expression in CRC cells was investigated using the demethylation reagent 5-Aza-CdR and transfection of miR-124 mimic/antimir. MSP revealed that miR-124 promoter region was hypermethylated, result in its significant downregulation in tumour tissues. We showed miR-124 expression was upregulated following 5-AZA-CdR treatment. Transfected Hct-116 cell line with miR-124 leads to decreased DNMT3B expression, cell proliferation, migration and invasion of HCT-116. In conclusion, our data indicate that miR-124 suppress colorectal cancer proliferation, migration and invasion through downregulating DNMT3B level.

Gene regulation in animal miRNA biogenesis

miRNAs are a class of noncoding RNAs of approximately 19-22 nucleotides that are widely found in animals, plants, bacteria and even viruses. Dysregulation of the expression profile of miRNAs is importantly linked to the development of diseases. Epigenetic modifications regulate gene expression and control cellular phenotypes. Although miRNAs are used as an epigenetic regulation tool, the biogenesis of miRNAs is also regulated by epigenetic events. Here the authors review the mechanisms and roles of epigenetic modification (DNA methylation, histone modifications), RNA modification and ncRNAs in the biogenesis of miRNAs, aiming to deepen the understanding of the miRNA biogenesis regulatory network.

Association Between Single Nucleotide Polymorphisms of miRNAs and Gastric Cancer: A Scoping Review

Background: Gastric cancer (GC) is the third leading cause of cancer-related mortality worldwide, and single nucleotide polymorphisms (SNPs) in microRNAs (miRNAs) are believed to affect the occurrence and progression of cancer by altering the expression and biological functions of miRNAs. Methods: The present scoping review was designed to evaluate and discuss microRNA SNPs (miR-SNPs) that have been found to be associated with GC in the following two contexts: (1) the biological effects on GC based on SNP localization; and (2) the associations between miRNA-SNPs and clinical factors (susceptibility, tumor size, metastasis, overall survival, and prognosis) of GC. Results and Conclusions: Information on miRNAs was collected, including the SNPs, their proven target genes, and the possible impact of the SNPs on GC outcome. Our findings suggest an etiological or modifying role for multiple miRNA SNPs (miR-499, miR-146a, miR-149, miR-148, miR-27a, miR-608, miR-196a-2) in GC and its progression. The findings of this study reinforce the multiple roles of miRNA SNPs in GC.

MicroRNA-570 targets the HSP chaperone network, increases proteotoxic stress and inhibits mammary tumor cell migration

The dynamic network of chaperone interactions known as the chaperome contributes significantly to the proteotoxic cell response and the malignant phenotype. To bypass the inherent redundancy in the network, we have used a microRNA (mir) approach to target multiple members of the chaperome simultaneously. We identified a potent microRNA, miR-570 that could bind the 3'untranslated regions of multiple HSP mRNAs and inhibit HSP synthesis. Transfection of cells with this miR species reduced expression of multiple HSPs, inhibited the heat shock response and reduced tumor cell growth while acted additively in combination with cytotoxic drugs. As overexpression of miR-570 elicited tumor suppressive effects, we inferred that this miR could play a potential role in inhibiting tumorigenesis and cancer cell growth. In accordance with this hypothesis, we determined a significant role for miR-570 in regulating markers of mammary tumor progression, including cell motility and invasion. Our data provide a proof of the principle that the tumor chaperome can be targeted by microRNAs suggesting a potential therapeutic avenue towards cancer therapy.

mRNA expression and epigenetic-based role of chromodomain helicase DNA-binding 5 in hepatocellular carcinoma

Objective

Chromodomain helicase DNA-binding 5 (CHD5) acts as a tumor suppressor gene in some cancers. CHD5 expression levels may affect an individual’s susceptibility to hepatocellular carcinoma (HCC). This study aimed to evaluate the methylation pattern of the CHD5 promoter region and the gene’s corresponding mRNA expression in HCC patients compared with healthy individuals.

Methods

In this case–control study, CHD5 mRNA gene expression levels and DNA methylation patterns were analyzed in 81 HCC patients and 90 healthy individuals by quantitative reverse transcription polymerase chain reaction and methylation-specific polymerase chain reaction, respectively.

Results

The CHD5 gene was hypermethylated in 61.8% of the HCC patients and 54.4% of the controls, and this difference was statistically significant. The CHD5 mRNA expression levels were significantly lower in the HCC patient group.

Conclusions

Hypermethylation of the CHD5 promoter region may significantly lower the expression of this gene, affecting the incidence and severity of HCC. The methylation status of CHD5 can also be further studied as a prognostic factor in HCC.

MicroRNA Methylome Signature and Their Functional Roles in Colorectal Cancer Diagnosis, Prognosis, and Chemoresistance

Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths worldwide. Despite significant advances in the diagnostic services and patient care, several gaps remain to be addressed, from early detection, to identifying prognostic variables, effective treatment for the metastatic disease, and the implementation of tailored treatment strategies. MicroRNAs, the short non-coding RNA species, are deregulated in CRC and play a significant role in the occurrence and progression. Nevertheless, microRNA research has historically been based on expression levels to determine its biological significance. The exact mechanism underpinning microRNA deregulation in cancer has yet to be elucidated, but several studies have demonstrated that epigenetic mechanisms play important roles in the regulation of microRNA expression, particularly DNA methylation. However, the methylation profiles of microRNAs remain unknown in CRC patients. Methylation is the next major paradigm shift in cancer detection since large-scale epigenetic alterations are potentially better in identifying and classifying cancers at an earlier stage than somatic mutations. This review aims to provide insight into the current state of understanding of microRNA methylation in CRC. The new knowledge from this study can be utilized for personalized health diagnostics, disease prediction, and monitoring of treatment.

MicroRNAs and drug resistance in colorectal cancer with special focus on 5-fluorouracil

Colorectal cancer is globally one of the most common cancers in all age groups. The current chemotherapy combinations for colorectal cancer treatment include 5-fluorouracil-based regimens; however, drug resistance remains one of the main reasons for chemotherapy failure and disease recurrence. Many studies have determined colorectal cancer chemoresistance mechanisms such as drug efflux, cell cycle arrest, DNA damage repair, apoptosis, autophagy, vital enzymes, epigenetic, epithelial-mesenchymal transition, stem cells, and immune system suppression. Several microRNAs affect drug resistance by regulating the drug resistance-related target genes in colorectal cancer. These drug resistance-related miRNAs may be used as promising biomarkers for predicting drug response or as potential therapeutic targets for treating patients with colorectal cancer. This work reviews and discuss the role of selected microRNAs in 5-fluorouracil resistance and their molecular mechanisms in colorectal cancer.

miR-29b-3p Inhibitor Alleviates Hypomethylation-Related Aberrations Through a Feedback Loop Between miR-29b-3p and DNA Methylation in Cardiomyocytes

As a member of the miR-29 family, miR-29b regulates global DNA methylation through target DNA methyltransferases (DNMTs) and acts as both a target and a key effector in DNA methylation. In this study, we found that miR-29b-3p expression was inversely correlated with DNMT expression in the heart tissues of patients with congenital heart disease (CHD), but whether it interacts with DNMTs in cardiomyocytes remains unknown. Further results revealed a feedback loop between miR-29b-3p and DNMTs in cardiomyocytes. Moreover, miR-29b-3p inhibitor relieved the deformity of hypomethylated zebrafish and restored the DNA methylation patterns in cardiomyocytes, resulting in increased proliferation and renormalization of gene expression. These results suggest mutual regulation between miR-29b-3p and DNMTs in cardiomyocytes and support the epigenetic normalization of miRNA-based therapy in cardiomyocytes.

Detection of Host Cell Gene/HPV DNA Methylation Markers: A Promising Triage Approach for Cervical Cancer

Cervical cancer is the most prevalent gynecologic malignancy, especially in women of low- and middle-income countries (LMICs). With a better understanding of the etiology and pathogenesis of cervical cancer, it has been well accepted that this type of cancer can be prevented and treated via early screening. Due to its higher sensitivity than cytology to identify precursor lesions of cervical cancer, detection of high-risk human papillomavirus (HR-HPV) DNA has been implemented as the primary screening approach. However, a high referral rate for colposcopy after HR-HPV DNA detection due to its low specificity in HR-HPV screening often leads to overtreatment and thus increases the healthcare burden. Emerging evidence has demonstrated that detection of host cell gene and/or HPV DNA methylation represents a promising approach for the early triage of cervical cancer in HR-HPV-positive women owing to its convenience and comparable performance to cytology, particularly in LMICs with limited healthcare resources. While numerous potential markers involving DNA methylation of host cell genes and the HPV genome have been identified thus far, it is crucial to define which genes or panels involving host and/or HPV are feasible and appropriate for large-scale screening and triage. An ideal approach for screening and triage of CIN/ICC requires high sensitivity and adequate specificity and is suitable for self-sampling and inexpensive to allow population-based screening, particularly in LMICs. In this review, we summarize the markers of host cell gene/HR-HPV DNA methylation and discuss their triage performance and feasibility for high-grade precancerous cervical intraepithelial neoplasia or worse (CIN2+ and CIN3+) in HR-HPV-positive women.

Epigenetic Regulation: A Link between Inflammation and Carcinogenesis

Simple Summary

Epigenetics encompasses all the modifications that occur within cells that are independent of gene mutations. The environment is the main influencer of these alterations. It is well known that a proinflammatory environment can promote and sustain the carcinogenic process and that this environment induces epigenetic alterations. In this review, we will report how a proinflammatory microenvironment that encircles the tumor core can be responsible for the induction of epigenetic drift.

Abstract

Epigenetics encompasses a group of dynamic, reversible, and heritable modifications that occur within cells that are independent of gene mutations. These alterations are highly influenced by the environment, from the environment that surrounds the human being to the internal microenvironments located within tissues and cells. The ways that pigenetic modifications promote the initiation of the tumorigenic process have been widely demonstrated. Similarly, it is well known that carcinogenesis is supported and prompted by a strong proinflammatory environment. In this review, we introduce our report of a proinflammatory microenvironment that encircles the tumor core but can be responsible for the induction of epigenetic drift. At the same time, cancer cells can alter their epigenetic profile to generate a positive loop in the promotion of the inflammatory process. Therefore, an in-depth understanding of the epigenetic networks between the tumor microenvironment and cancer cells might highlight new targetable mechanisms that could prevent tumor progression.

miR-146b-5p and miR-520h Expressions Are Upregulated in Serum of Women with Recurrent Spontaneous Abortion

Unexplained recurrent spontaneous abortion (URSA) is characterized by two or more consecutive pregnancy losses before the 20th week of gestation with unknown etiology. Dysregulation of microRNAs (miRNAs) expression has been reported in reproductive diseases. This study aimed to compare differentially expressed miRNAs in the serum samples between URSA patients and healthy individuals. URSA cases were confirmed by a gynecologist. Peripheral blood sample was‏ gathered from 9 URSA patients, 15 normal pregnant, and 10 non-pregnant women without abortion history. After separating serum, the expression levels of the miR-101-3p, miR-517c-3p, miR-146b-5p, miR-221-3p, and miR-520 h were measured by qRT-PCR assay. The circulating level of miR-520 h in URSA patients was significantly up-regulated compared with healthy pregnant (P < 0.01) and healthy non-pregnant (P = 0.002) women. Furthermore, miR-520 h expression was significantly different between healthy non-pregnant and pregnant women (P = 0.002). Statistical analysis indicated miR-146b-5p expression was significantly up-regulated in URSA patients compared to normal pregnant women (P = 0.018). However, the transcription level of miR-146b-5p was insignificantly different between normal non-pregnant women and the other two groups. Also, circulating levels of miR-101-3p, miR-221-3p, and miR-517c-3p were not significantly different in the studied groups. Statistical analysis showed significant correlations between both miR-221-3p and miR-517c-3p and other miRNAs (P < 0.05). The circulating levels of miR-520 h and miR-146b-5p could be considered biomarkers for URSA diagnosis. Also, miR-517c-3p and miR-221-3p might play a regulatory role in other miRNAs expressions during pregnancy. Previous work, in contrary to our findings, claims that the expression levels of miR-221-3p, miR-101-3p, and miR-517c-3p increased in plasma and tissue samples of patients with URSA. However, our research for the first time indicates that the expression level of miR-520 h and miR-146b-5p in the serum of these patients has increased. Future investigations are necessary to confirm these findings.

The Role of miRNA in Tumor Immune Escape and miRNA-Based Therapeutic Strategies

Tumor immune escape is a critical step in the malignant progression of tumors and one of the major barriers to immunotherapy, making immunotherapy the most promising therapeutic approach against tumors today. Tumor cells evade immune surveillance by altering the structure of their own, or by causing abnormal gene and protein expression, allowing for unrestricted development and invasion. These genetic or epigenetic changes have been linked to microRNAs (miRNAs), which are important determinants of post-transcriptional regulation. Tumor cells perform tumor immune escape by abnormally expressing related miRNAs, which reduce the killing effect of immune cells, disrupt the immune response, and disrupt apoptotic pathways. Consequently, there is a strong trend toward thoroughly investigating the role of miRNAs in tumor immune escape and utilizing them in tumor treatment. However, because of the properties of miRNAs, there is an urgent need for a safe, targeted and easily crossed biofilm vehicle to protect and deliver them in vivo, and exosomes, with their excellent biological properties, have successfully beaten traditional vehicles to provide strong support for miRNA therapy. This review summarizes the multiple roles of miRNAs in tumor immune escape and discusses their potential applications as an anti-tumor therapy. Also, this work proposes exosomes as a new opportunity for miRNA therapy, to provide novel ideas for the development of more effective tumor-fighting therapeutic approaches based on miRNAs.

Epigenetic Silencing of Tumor Suppressor lncRNA NKILA: Implication on NF-κB Signaling in Non-Hodgkin’s Lymphoma

The long non-coding RNA (lncRNA) NKILA, localized to 20q13.31, is a negative regulator of NF-κB signaling implicated in carcinogenesis. As a CpG island is embedded in the promoter region of NKILA, it is hypothesized as a tumor suppressor lncRNA silenced by promoter DNA methylation in non-Hodgkin’s lymphoma (NHL). By pyrosequencing-verified methylation-specific PCR, NKILA methylation was detected in 1/10 (10%) NHL cell lines, but not in normal peripheral blood buffy coats or tonsils. NKILA methylation correlated with the repression of NKILA in cell lines. Hypomethylation treatment with 5-Aza-2′-deoxycytidine resulted in promoter demethylation and the re-expression of NKILA. In 102 NHL primary samples, NKILA was methylated in 29 (51.79%) diffuse large B-cell lymphoma (DLBCL) and 4 (20%) peripheral T-cell lymphoma cases, but unmethylated in all 26 mantle cell lymphoma cases. Mechanistically, the knockdown of NKILA resulted in promoting IkBα phosphorylation, associated with nucleus translocation of total p65 and phosphorylated p65 in SU-DHL-1 cells, hence constitutive NF-κB activation. Functionally, the knockdown of NKILA in SU-DHL-1 cells led to decreased cell death and increased cellular proliferation. Collectively, NKILA was a tumor suppressor lncRNA frequently hypermethylated in DLBCL. Promoter DNA methylation-mediated NKILA silencing resulted in increased cellular proliferation and decreased cell death via the repression of NF-κB signaling in NHL.

Promoter Hypomethylation of miR-124 Gene Is Associated With Major Depressive Disorder

Based on our previous studies and other evidence, miR-124 is an important biomarker and therapeutic target for major depressive disorder (MDD). The aim of this study was to clarify the role of miR-124 methylation in MDD and antidepressant effects from the perspective of epigenetics. MethylTarget™ was used to detect methylation levels of the three miR-124 precursor genes (MIR124-1, MIR124-2, and MIR124-3) in 33 pre- and post-treatment MDD patients and 33 healthy controls. A total of 11 cytosine-phosphate-guanine (CpG) islands in the three miR-124 precursor genes, including 222 CpG sites, were detected. All CpG islands were hypomethylated in MDD patients when compared to healthy controls and seven CpG regions were still identified with a statistically significant difference after Bonferroni correction. In addition, 137 of 222 CpG sites were found a statistical difference between MDD patients and controls, and 40 CpG sites were still statistically significant after Bonferroni correction. After performing the LASSO regression model, seven biomarkers with differential methylation among 40 CpG sites were identified. Mean methylation score was lower in MDD patients (z = -5.84, p = 5.16E-9). The AUC value reached 0.917 (95% CI: 0.854-0.981) to discriminate MDD and controls. No changes in methylation of the three miR-124 precursor genes were found in MDD patients following antidepressant treatment. The methylation of miR-124 could be a promising diagnostic biomarker for MDD.