N6-methyladenosine METTL3 promotes cervical cancer tumorigenesis and Warburg effect through YTHDF1/HK2 modification

Insights into the role of RNA m6A modification in the metabolic process and related diseases

According to the latest consensus, many traditional diseases are considered metabolic diseases, such as cancer, type 2 diabetes, obesity, and cardiovascular disease. Currently, metabolic diseases are increasingly prevalent because of the ever-improving living standards and have become the leading threat to human health. Multiple therapy methods have been applied to treat these diseases, which improves the quality of life of many patients, but the overall effect is still unsatisfactory. Therefore, intensive research on the metabolic process and the pathogenesis of metabolic diseases is imperative. N6-methyladenosine (m6A) is an important modification of eukaryotic RNAs. It is a critical regulator of gene expression that is involved in different cellular functions and physiological processes. Many studies have indicated that m6A modification regulates the development of many metabolic processes and metabolic diseases. In this review, we summarized recent studies on the role of m6A modification in different metabolic processes and metabolic diseases. Additionally, we highlighted the potential m6A-targeted therapy for metabolic diseases, expecting to facilitate m6A-targeted strategies in the treatment of metabolic diseases.

M6A-induced transcription factor IRF5 contributes to the progression of cervical cancer by upregulating PPP6C

Cervical cancer (CC) is a gynaecological malignancy tumour that seriously threatens women's health. Recent evidence has identified that interferon regulatory factor 5 (IRF5), a nucleoplasm shuttling protein, is a pivotal transcription factor regulating the growth and metastasis of various human tumours. This study aimed to investigate the function and molecular basis of IRF5 in CC development. IRF5, protein phosphatase 6 catalytic subunit (PPP6C) and methyltransferase-like 3 (METTL3) mRNA levels were evaluated by quantitative real-time (qRT)-polymerase chain reaction (PCR). IRF5, PPP6C, METTL3, B-cell lymphoma 2 and Bax protein levels were detected using western blot. Cell proliferation, migration, invasion, angiogenesis and apoptosis were determined by using colony formation, 5-ethynyl-2'-deoxyuridine (EdU), transwell, tube formation assay and flow cytometry assay, respectively. Glucose uptake and lactate production were measured using commercial kits. Xenograft tumour assay in vivo was used to explore the role of IRF5. After JASPAR predication, binding between IRF5 and PPP6C promoter was verified using chromatin immunoprecipitation and dual-luciferase reporter assays. Moreover, the interaction between METTL3 and IRF5 was verified using methylated RNA immunoprecipitation (MeRIP). IRF5, PPP6C and METTL3 were highly expressed in CC tissues and cells. IRF5 silencing significantly inhibited cell proliferation, migration, invasion, angiogenesis and glycolytic metabolism in CC cells, while induced cell apoptosis. Furthermore, the absence of IRF5 hindered tumour growth in vivo. At the molecular level, IRF5 might bind with PPP6C to positively regulate the expression of PPP6C mRNA. Meanwhile, IRF5 was identified as a downstream target of METTL3-mediated m6A modification. METTL3-mediated m6A modification of mRNA might promote CC malignant progression by regulating PPP6C, which might provide a promising therapeutic target for CC treatment.

WTAP promotes proliferation of esophageal squamous cell carcinoma via m6A-dependent epigenetic promoting of PTP4A1

Esophageal squamous cell carcinoma (ESCC) represents a frequently seen malignancy with high prevalence worldwide. Although current studies have shown that Wilms' tumor 1-associated protein (WTAP), a major part in the methyltransferase complex, is involved in various tumor pathological processes, its specific role in ESCC remains unclear. Therefore, the present work focused on exploring WTAP's function and mechanism in ESCC progression using clinical ESCC specimens, ESCC cells, and mammalian models. Firstly, we proved WTAP was significantly upregulated within ESCC, and WTAP mRNA expression showed a good diagnostic performance for ESCC. Functionally, WTAP positively regulated in-vivo and in-vitro ESCC cells' malignant phenotype through the AKT-mTOR signaling pathway. Meanwhile, WTAP positively regulated the N6-methyladenosine (m6A) modification levels in ESCC cells. Protein tyrosine phase type IVA member 1 (PTP4A1) was confirmed to be the m6A target of WTAP, and WTAP positively regulated the expression of PTP4A1. Further study revealed that PTP4A1 showed high expression within ESCC. Silencing PTP4A1 inhibited the AKT-mTOR signaling pathway to suppress ESCC cells' proliferation. Rescue experiments showed that silencing PTP4A1 partially reversed the WTAP-promoting effect on ESCC cells' proliferation ability. Mechanistically, WTAP regulated PTP4A1 expression to activate the AKT-mTOR pathway, promoting the proliferation of ESCC cells. Our study demonstrated that WTAP regulates the progression of ESCC through the m6A-PTP4A1-AKT-mTOR signaling axis and that WTAP is a potential target for diagnosing and treating ESCC.

Targeting FTO suppresses hepatocellular carcinoma by inhibiting ERBB3 and TUBB4A expression

Fat mass and obesity-associated protein (FTO) is an N6-methyladenosine (m6A) demethylase and plays critical oncogenic roles in multiple cancers. Here we show that FTO is an effective target in hepatocellular carcinoma (HCC). FTO is highly expressed in patients with HCC. Genetic depletion of Fto dramatically attenuated HCC progression in mice. Pharmacological inhibition of FTO by FB23/FB23-2 markedly suppressed the proliferation and migration of HCC cell lines in vitro and inhibited HCC tumorigenicity in xeno-transplanted mice. Mechanistically, FB23-2 suppressed the expression of Erb-b2 receptor tyrosine kinase 3 (ERBB3) and human tubulin beta class Iva (TUBB4A) by increasing the m6A level in these mRNA transcripts. The decrease in ERBB3 expression resulted in the inhibition of Akt-mTOR signaling, which subsequently impaired the proliferation and survival of HCC cells. Moreover, FB23-2 disturbed the stability of the tubulin cytoskeleton, whereas overexpression of TUBB4A rescued the migration of HCC cells. Collectively, our study demonstrates that FTO plays a critical role in HCC by maintaining the proliferation and migration of cells and highlights the potential of FTO inhibitors for targeting HCC.

DUSP5 regulated by YTHDF1-mediated m6A modification promotes epithelial-mesenchymal transition and EGFR-TKI resistance via the TGF-β/Smad signaling pathway in lung adenocarcinoma

BACKGROUND

Lung adenocarcinoma (LUAD) patients have a dismal survival rate because of cancer metastasis and drug resistance. The study aims to identify the genes that concurrently modulate EMT, metastasis and EGFR-TKI resistance, and to investigate the underlying regulatory mechanisms.

METHODS

Cox regression and Kaplan-Meier analyses were applied to identify prognostic oncogenes in LUAD. Gene set enrichment analysis (GSEA) was used to indicate the biological functions of the gene. Wound-healing and Transwell assays were used to detect migratory and invasive ability. EGFR-TKI sensitivity was evaluated by assessing the proliferation, clonogenic survival and metastatic capability of cancer cells with treatment with gefitinib. Methylated RNA immunoprecipitation (MeRIP) and RNA immunoprecipitation (RIP) analyses established the level of m6A modification present on the target gene and the protein's capability to interact with RNA, respectively. Single-sample gene set enrichment (ssGSEA) algorithm used to investigate levels of immune cell infiltration.

RESULTS

Our study identified dual-specificity phosphatase 5 (DUSP5) as a novel and powerful predictor of adverse outcomes for LUAD by using public datasets. Functional enrichment analysis found that DUSP5 was positively enriched in EMT and transforming growth factor-beta (TGF-β) signaling pathway, a prevailing pathway involved in the induction of EMT. As expected, DUSP5 knockdown suppressed EMT via inhibiting the canonical TGF-β/Smad signaling pathway in in vitro experiments. Consistently, knockdown of DUSP5 was first found to inhibit migratory ability and invasiveness of LUAD cells in in vitro and prevent lung metastasis in in vivo. DUSP5 knockdown re-sensitized gefitinib-resistant LUAD cells to gefitinib, accompanying reversion of EMT progress. In LUAD tissue samples, we found 14 cytosine-phosphate-guanine (CpG) sites of DUSP5 that were negatively associated with DUSP5 gene expression. Importantly, 5'Azacytidine (AZA), an FDA-approved DNA methyltransferase inhibitor, restored DUSP5 expression. Moreover, RIP experiments confirmed that YTH N6-methyladenosine RNA binding protein 1 (YTHDF1), a m6A reader protein, could bind DUSP5 mRNA. YTHDF1 promoted DUSP5 expression and the malignant phenotype of LUAD cells. In addition, the DUSP5-derived genomic model revealed the two clusters with distinguishable immune features and tumor mutational burden (TMB).

CONCLUSIONS

Briefly, our study discovered DUSP5 which was regulated by epigenetic modification, might be a potential therapeutic target, especially in LUAD patients with acquired EGFR-TKI resistance.

Unraveling the cross-talk between N6-methyladenosine modification and non-coding RNAs in breast cancer: Mechanisms and clinical implications

In recent years, breast cancer (BC) has surpassed lung cancer as the most common malignant tumor worldwide and remains the leading cause of cancer death in women. The etiology of BC usually involves dysregulation of epigenetic mechanisms and aberrant expression of certain non-coding RNAs (ncRNAs). N6-methyladenosine (m6A), the most prevalent RNA modification in eukaryotes, widely exists in ncRNAs to affect its biosynthesis and function, and is an important regulator of tumor-related signaling pathways. Interestingly, ncRNAs can also regulate or target m6A modification, playing a key role in cancer progression. However, the m6A-ncRNAs regulatory network in BC has not been fully elucidated, especially the regulation of m6A modification by ncRNAs. Therefore, in this review, we comprehensively summarize the interaction mechanisms and biological significance of m6A modifications and ncRNAs in BC. Meanwhile, we also focused on the clinical application value of m6A modification in BC diagnosis and prognosis, intending to explore new biomarkers and potential therapeutic targets.

N6-methyladenosine methylation on FSCN1 mediated by METTL14/IGF2BP3 contributes to human papillomavirus type 16-infected cervical squamous cell carcinoma

Human papillomavirus (HPV) infection has been reported to be associated with N6-methyladenosine (m6A) modification in cancers. However, the underlying mechanism by which m6A methylation participates in HPV-related cervical squamous cell carcinoma (CSCC) remains largely unclear. In this study, we observed that m6A regulators methyltransferase like protein (METTL14) and insulin like growth factor 2 mRNA binding protein 3 (IGF2BP3) were upregulated in HPV-positive CSCC tissues and cell lines, and their high expression predicted poor prognosis for HPV-infected CSCC patients. Cellular functional experiments verified that HPV16 oncogenes E6/E7 upregulated the expression of METTL14 and IGF2BP3 to promote cell proliferation and epithelial mesenchymal transition of CSCC cells. Next, we found that E6/E7 stabilized fascin actin-bundling protein 1 (FSCN1) mRNA and elevated FSCN1 expression in CSCC cells through upregulating METTL14/IGF2BP3-mediated m6A modification, and FSCN1 expression was also validated to be positively associated with worse outcomes of HPV-positive CSCC patients. Finally, HPV16-positive CSCC cell lines SiHa and CaSki were transfected with knockdown vector for E6/E7 or METTL14/IGF2BP3 and overexpressing vector for FSCN1, and functional verification experiments were performed through using MTT assay, flow cytometry, wound healing assay and tumour formation assay. Results indicated that knockdown of E6/E7 or METTL14/IGF2BP3 suppressed cell proliferation, migration and tumorigenesis, and accelerated cell apoptosis of HPV-positive CSCC cells. Their tumour-suppressive effects were abolished through overexpressing FSCN1. Overall, HPV E6/E7 advanced CSCC development through upregulating METTL14/IGF2BP3-mediated FSCN1 m6A modification.

METTL3 inhibits BMSC apoptosis and facilitates osteonecrosis repair via an m6A-IGF2BP2-dependent mechanism

Hypoxia-induced apoptosis of bone marrow mesenchymal stem cells (BMSCs) limits the efficacy of their transplantation for steroid-induced osteonecrosis of the femoral head (SONFH). As apoptosis and RNA methylation are closely related, exploring the role and mechanism of RNA methylation in hypoxic apoptosis of BMSCs is expected to identify new targets for transplantation of BMSCs for SONFH and enhance transplantation efficacy. We performed methylated RNA immunoprecipitation sequencing (MeRIP-seq) combined with RNA-seq on a hypoxia-induced apoptosis BMSC model and found that the RNA methyltransferase-like 3 (METTL3) is involved in hypoxia-induced BMSC apoptosis. The expression of METTL3 was downregulated in BMSCs after hypoxia and in BMSCs implanted in osteonecrosis areas. Knockdown of METLL3 under normoxic conditions promoted apoptosis of BMSCs. In contrast, overexpression of METTL3 promoted the survival of BMSCs under hypoxic conditions, and overexpression of METTL3 promoted the survival of BMSCs in the osteonecrosis area and the repair of the osteonecrosis area. Regarding the mechanism, the m6A levels of the mRNAs of anti-apoptotic genes Bcl-2, Mcl-1, and BIRC5 were significantly increased upon the overexpression of METTL3 under hypoxic conditions, which promoted the binding of Bcl-2, Mcl-1, and BIRC5 mRNAs to IGF2BP2, enhanced the mRNA stability, and increased the protein expression of the three anti-apoptotic genes. In conclusion, overexpression of METTL3 promoted m6A modification of mRNAs of Bcl-2, Mcl-1, and BIRC5, promoted the binding of IGF2BP2 to the above-mentioned mRNAs, enhanced mRNA stability, inhibited hypoxia-induced BMSC apoptosis, and promoted repair of SONFH, thereby providing novel targets for transplantation of BMSCs for SONFH.

Navigating the landscape of epitranscriptomics and host immunity

RNA modifications, also termed epitranscriptomic marks, encompass chemical alterations to individual nucleotides, including processes such as methylation and editing. These marks contribute to a wide range of biological processes, many of which are related to host immune system defense. The functions of immune-related RNA modifications can be categorized into three main groups: regulation of immunogenic RNAs, control of genes involved in innate immune response, and facilitation of adaptive immunity. Here, we provide an overview of recent research findings that elucidate the contributions of RNA modifications to each of these processes. We also discuss relevant methods for genome-wide identification of RNA modifications and their immunogenic substrates. Finally, we highlight recent advances in cancer immunotherapies that aim to reduce cancer cell viability by targeting the enzymes responsible for RNA modifications. Our presentation of these dynamic research avenues sets the stage for future investigations in this field.

N6-methyladenosine in myeloid cells: a novel regulatory factor for inflammation-related diseases

N6-methyladenosine (m6A) is one of the most abundant epitranscriptomic modifications on eukaryotic mRNA. Evidence has highlighted that m6A is altered in response to inflammation-related factors and it is closely associated with various inflammation-related diseases. Multiple subpopulations of myeloid cells, such as macrophages, dendritic cells, and granulocytes, are crucial for the regulating of immune process in inflammation-related diseases. Recent studies have revealed that m6A plays an important regulatory role in the functional of multiple myeloid cells. In this review, we comprehensively summarize the function of m6A modification in myeloid cells from the perspective of myeloid cell production, activation, polarization, and migration. Furthermore, we discuss how m6A-mediated myeloid cell function affects the progression of inflammation-related diseases, including autoimmune diseases, chronic metabolic diseases, and malignant tumors. Finally, we discuss the challenges encountered in the study of m6A in myeloid cells, intended to provide a new direction for the study of the pathogenesis of inflammation-related diseases.

RNA m6A methylation and regulatory proteins in pulmonary arterial hypertension

m6A (N6‑methyladenosine) is the most common and abundant apparent modification in mRNA of eukaryotes. The modification of m6A is regulated dynamically and reversibly by methyltransferase (writer), demethylase (eraser), and binding protein (reader). It plays a significant role in various processes of mRNA metabolism, including regulation of transcription, maturation, translation, degradation, and stability. Pulmonary arterial hypertension (PAH) is a malignant cardiopulmonary vascular disease characterized by abnormal proliferation of pulmonary artery smooth muscle cells. Despite the existence of several effective and targeted therapies, there is currently no cure for PAH and the prognosis remains poor. Recent studies have highlighted the crucial role of m6A modification in cardiovascular diseases. Investigating the role of RNA m6A methylation in PAH could provide valuable insights for drug development. This review aims to explore the mechanism and function of m6A in the pathogenesis of PAH and discuss the potential targeting of RNA m6A methylation modification as a treatment for PAH.

METTL3-mediated m6A methylation of SLC38A1 stimulates cervical cancer growth

The objective of this study was to better characterize the role of the glutamine transporter SLC38A1 in cervical cancer and explore the underlying mechanisms. Data from public databases and clinical cervical cancer tissue samples were used to assess the expression of SLC38A1 and its prognostic significance. Immunohistochemical staining, qRT-PCR, and Western blotting were used to evaluate the expression of relevant genes and proteins. Cell viability, cell cycle, apoptosis, and intracellular glutamine content were measured using CCK-8, flow cytometry, and biochemical assays. Additionally, the RNA immunoprecipitation (RIP) assay was used to examine the impact of METTL3/IGF2BP3 on the m6A modification of the SLC38A1 3'UTR. Both cervical cancer specimens and cells showed significantly increased expression of SLC38A1 and its expression correlated with an unfavorable prognosis. Knockdown of SLC38A1 inhibited cell viability and cell cycle progression, induced apoptosis, and suppressed tumor growth in vivo. Glutaminase-1 inhibitor CB-839 reversed the effects of SLC38A1 overexpression. METTL3 promoted m6A modification of SLC38A1 and enhanced its mRNA stability through IGF2BP3 recruitment. Moreover, METTL3 silencing inhibited cell viability, cell cycle progression, intracellular glutamine content, and induced apoptosis, but these effects were reversed by SLC38A1 overexpression. In conclusion, METTL3-mediated m6A methylation of SLC38A1 stimulates cervical cancer progression. SLC38A1 inhibition is a potential therapeutic strategy for cervical cancer.

Abnormal changes in metabolites caused by m6A methylation modification: The leading factors that induce the formation of immunosuppressive tumor microenvironment and their promising potential for clinical application

BACKGROUND

N6-methyladenosine (m6A) RNA methylation modifications have been widely implicated in the metabolic reprogramming of various cell types within the tumor microenvironment (TME) and are essential for meeting the demands of cellular growth and maintaining tissue homeostasis, enabling cells to adapt to the specific conditions of the TME. An increasing number of research studies have focused on the role of m6A modifications in glucose, amino acid and lipid metabolism, revealing their capacity to induce aberrant changes in metabolite levels. These changes may in turn trigger oncogenic signaling pathways, leading to substantial alterations within the TME. Notably, certain metabolites, including lactate, succinate, fumarate, 2-hydroxyglutarate (2-HG), glutamate, glutamine, methionine, S-adenosylmethionine, fatty acids and cholesterol, exhibit pronounced deviations from normal levels. These deviations not only foster tumorigenesis, proliferation and angiogenesis but also give rise to an immunosuppressive TME, thereby facilitating immune evasion by the tumor.

AIM OF REVIEW

The primary objective of this review is to comprehensively discuss the regulatory role of m6A modifications in the aforementioned metabolites and their potential impact on the development of an immunosuppressive TME through metabolic alterations.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review aims to elaborate on the intricate networks governed by the m6A-metabolite-TME axis and underscores its pivotal role in tumor progression. Furthermore, we delve into the potential implications of the m6A-metabolite-TME axis for the development of novel and targeted therapeutic strategies in cancer research.

RNA methylation patterns, immune characteristics, and autophagy-related mechanisms mediated by N6-methyladenosine (m6A) regulatory factors in venous thromboembolism

Recent studies have found a link between deep vein thrombosis and inflammatory reactions. N6-methyladenosine (m6A), a crucial element in immunological regulation, is believed to contribute to the pathophysiology of venous thromboembolism (VTE). However, how the m6A-modified immune microenvironment is involved in VTE remains unclear. In the present study, we identified a relationship between VTE and the expression of several m6A regulatory elements by analyzing peripheral blood samples from 177 patients with VTE and 88 healthy controls from public GEO databases GSE19151 and GSE48000. We used machine learning to identify essential genes and constructed a diagnostic model for VTE using multivariate logistic regression. Unsupervised cluster analysis revealed a marked difference between m6A modification patterns in terms of immune cell infiltration, inflammatory reactivity, and autophagy. We identified two m6A-related autophagy genes (i.e., CHMP2B and SIRT1) and the crucial m6A regulator YTHDF3 using bioinformatics. We also examined two potential mechanisms through which YTHDF3 may affect VTE. m6A modification, immunity, and autophagy are closely linked in VTE, offering novel mechanistic and therapeutic insights.

A comprehensive review of m6A research in cervical cancer

Cervical cancer (CC) remains one of the most common malignancies among women worldwide, posing a serious threat to women's health. N6-methyladenosine (m6A) modification, as the most abundant type of RNA methylation modification, and has been found to play a crucial role in various cancers. Current research suggests a close association between RNA m6A modification and the occurrence and progression of CC, encompassing disruptions in m6A levels and its regulatory machinery. This review summarizes the current status of m6A modification research in CC, explores the mechanisms underlying m6A levels and regulators (methyltransferases, demethylases, reader proteins) in CC and examines the application of small-molecule inhibitors of m6A regulators in disease treatment. The findings provide new insights into the future treatment of CC.

Transcriptional regulation and post-translational modifications in the glycolytic pathway for targeted cancer therapy

Cancer cells largely rely on aerobic glycolysis or the Warburg effect to generate essential biomolecules and energy for their rapid growth. The key modulators in glycolysis including glucose transporters and enzymes, e.g. hexokinase 2, enolase 1, pyruvate kinase M2, lactate dehydrogenase A, play indispensable roles in glucose uptake, glucose consumption, ATP generation, lactate production, etc. Transcriptional regulation and post-translational modifications (PTMs) of these critical modulators are important for signal transduction and metabolic reprogramming in the glycolytic pathway, which can provide energy advantages to cancer cell growth. In this review we recapitulate the recent advances in research on glycolytic modulators of cancer cells and analyze the strategies targeting these vital modulators including small-molecule inhibitors and microRNAs (miRNAs) for targeted cancer therapy. We focus on the regulation of the glycolytic pathway at the transcription level (e.g., hypoxia-inducible factor 1, c-MYC, p53, sine oculis homeobox homolog 1, N6-methyladenosine modification) and PTMs (including phosphorylation, methylation, acetylation, ubiquitination, etc.) of the key regulators in these processes. This review will provide a comprehensive understanding of the regulation of the key modulators in the glycolytic pathway and might shed light on the targeted cancer therapy at different molecular levels.

Integrated analysis of m6A regulator-mediated RNA methylation modification patterns and immune characteristics in Sjögren's syndrome

The epigenetic modifier N6-methyladenosine (m6A), recognized as the most prevalent internal modification in messenger RNA (mRNA), has recently emerged as a pivotal player in immune regulation. Its dysregulation has been implicated in the pathogenesis of various autoimmune conditions. However, the implications of m6A modification within the immune microenvironment of Sjögren's syndrome (SS), a chronic autoimmune disorder characterized by exocrine gland dysfunction, remain unexplored. Herein, we leverage an integrative analysis combining public database resources and novel sequencing data to investigate the expression profiles of m6A regulatory genes in SS. Our cohort comprised 220 patients diagnosed with SS and 62 healthy individuals, enabling a comprehensive evaluation of peripheral blood at the transcriptomic level. We report a significant association between SS and altered expression of key m6A regulators, with these changes closely tied to the activation of CD4+ T cells. Employing a random forest (RF) algorithm, we identified crucial genes contributing to the disease phenotype, which facilitated the development of a robust diagnostic model via multivariate logistic regression analysis. Further, unsupervised clustering revealed two distinct m6A modification patterns, which were significantly associated with variations in immunocyte infiltration, immune response activity, and biological function enrichment in SS. Subsequently, we proceeded with a screening process aimed at identifying genes that were differentially expressed (DEGs) between the two groups distinguished by m6A modification. Leveraging these DEGs, we employed weight gene co-expression network analysis (WGCNA) to uncover sets of genes that exhibited strong co-variance and hub genes that were closely linked to m6A modification. Through rigorous analysis, we identified three critical m6A regulators - METTL3, ALKBH5, and YTHDF1 - alongside two m6A-related hub genes, COMMD8 and SRP9. These elements collectively underscore a complex but discernible pattern of m6A modification that appears to be integrally linked with SS's pathogenesis. Our findings not only illuminate the significant correlation between m6A modification and the immune microenvironment in SS but also lay the groundwork for a deeper understanding of m6A regulatory mechanisms. More importantly, the identification of these key regulators and hub genes opens new avenues for the diagnosis and treatment of SS, presenting potential targets for therapeutic intervention.

METTL3-mediated HSPA9 m6A modification promotes malignant transformation and inhibits cellular senescence by regulating exosomal mortalin protein in cervical cancer

The role of RNA methyltransferase 3 (METTL3) in tumor progression when tethered to aberrantly expressed oncogenes remains unknown. In especial, the correlation between cervical cancer (CCa)-derived exosomes and m6A methylation in malignant traits of cervical epithelium is currently elusive. Mortalin expression was found to be up-regulated in plasma exosomes isolated from CCa patients. Furthermore, mortalin gained increased mRNA stability and enhanced translation efficiency via the m6A methylation in the HSPA9 mRNA 3'UTR, which was catalysed by METTL3 in CCa cells. Exosomal mortalin overexpression significantly promoted the proliferation, migration and invasion of CCa both in vitro and in vivo. Additionally, exosome-encapsulated mortalin suppressed cellular senescence and facilitated malignant transformation by blocking nuclear transport of p53, thereby preventing the p53-Gadd45A interaction and resulting in inactivation of p53. Our studies demonstrated the significant role of METTL3 mediated exosomal mortalin in malignant transformation and cellular senescence suppression of CCa. Exosomal mortalin could clinically serve as a potential early-diagnosis biomarker and therapeutic target for CCa given its abundance and propensity to be found.

RNA modifications in cellular metabolism: implications for metabolism-targeted therapy and immunotherapy

Cellular metabolism is an intricate network satisfying bioenergetic and biosynthesis requirements of cells. Relevant studies have been constantly making inroads in our understanding of pathophysiology, and inspiring development of therapeutics. As a crucial component of epigenetics at post-transcription level, RNA modification significantly determines RNA fates, further affecting various biological processes and cellular phenotypes. To be noted, immunometabolism defines the metabolic alterations occur on immune cells in different stages and immunological contexts. In this review, we characterize the distribution features, modifying mechanisms and biological functions of 8 RNA modifications, including N6-methyladenosine (m6A), N6,2'-O-dimethyladenosine (m6Am), N1-methyladenosine (m1A), 5-methylcytosine (m5C), N4-acetylcytosine (ac4C), N7-methylguanosine (m7G), Pseudouridine (Ψ), adenosine-to-inosine (A-to-I) editing, which are relatively the most studied types. Then regulatory roles of these RNA modification on metabolism in diverse health and disease contexts are comprehensively described, categorized as glucose, lipid, amino acid, and mitochondrial metabolism. And we highlight the regulation of RNA modifications on immunometabolism, further influencing immune responses. Above all, we provide a thorough discussion about clinical implications of RNA modification in metabolism-targeted therapy and immunotherapy, progression of RNA modification-targeted agents, and its potential in RNA-targeted therapeutics. Eventually, we give legitimate perspectives for future researches in this field from methodological requirements, mechanistic insights, to therapeutic applications.

The m6A methyltransferase RBM15 affects tumor cell stemness and progression of cervical cancer by regulating the stability of lncRNA HEIH

Cervical cancer (CC), as a common female malignant tumor in the world, is an important risk factor endangering women's health worldwide. The purpose of this study was to investigate the role of RBM15 in CC. The TCGA database was used to screen differentially expressed m6A genes in normal and tumor tissues. QRT-PCR was used to quantify HEIH, miR-802, EGFR, cell stemness, and epithelial-mesenchymal transition (EMT)-related genes. The interaction between HEIH and miR-802 was verified by dual-luciferase reporter assay and RIP assay. The occurrence of tumor cells after different treatments was detected by CCK-8, transwell and EdU staining. BALB/c nude mice were used to examine the effects of different treatments on tumor growth and cell stemness in vivo. RBM15 was upregulated in tumor tissues and cells. M6A was highly enriched in HEIH and enhances its RNA stability. HEIH acts as an oncogenic lncRNA to promote CC cell proliferation, migration and tumor growth. Mechanistically, HEIH regulates tumor cell stemness and promotes the proliferation and migration of CC cells by competitively adsorbing miR-802 and up-regulating the expression of EGFR. In short, our data shown that the m6A methyltransferase RBM15 could affect tumor cell proliferation, metastasis and cell stemness by stabilizing HEIH expression.

Methyltransferase-like 3-mediated m6A modification of miR-1908-5p contributes to nasopharyngeal carcinoma progression by targeting homeodomain-only protein homeobox

BACKGROUND

N6-methyladenosine (m6A) modification interacting microRNAs (miRNAs) have been confirmed to participate in nasopharyngeal carcinoma (NPC) progression. This research investigated miR-1908-5p's function and regulatory mechanism in the tumorigenesis of NPC via m6A modification and targeting a key gene.

METHODS

The levels of miR-1908-5p, homeodomain-only protein homeobox (HOPX), and methyltransferase-like 3 (METTL3) expressions were detected via RT-qPCR. The correlation between miR-1908-5p and the HOPX/METTL3 axis, as well as their regulatory mechanism, was investigated by dual luciferase reporter, western blotting, and MeRIP assays. Moreover, the bio-functions of miR-1908-5p, HOPX, and METTL3 in NPC were explored through CCK8, transwell, caspase-3 activity, and xenograft tumor assays.

RESULTS

RT-qPCR results indicated a miR-1908-5p upregulation in NPC. Knocking down miR-1908-5p diminished the NPC cell viability and migration in vitro. In vivo, downregulating miR-1908-5p repressed NPC cell tumor growth. Moreover, HOPX was specifically targeted by miR-1908-5p, and HOPX downregulation led to reversal of the anti-tumor impact of the miR-1908-5p inhibitor against NPC cell malignancy. Also, METTL3 could mediate the m6A modification of miR-1908-5p to regulate its influence on NPC cells.

CONCLUSION

This study demonstrated that the METTL3-mediated m6A modification of miR-1908-5p enhanced the tumorigenesis of NPC by targeting HOPX. These findings propose new insights for NPC diagnosis and therapy.

Targeting the Warburg effect: A revisited perspective from molecular mechanisms to traditional and innovative therapeutic strategies in cancer

Cancer reprogramming is an important facilitator of cancer development and survival, with tumor cells exhibiting a preference for aerobic glycolysis beyond oxidative phosphorylation, even under sufficient oxygen supply condition. This metabolic alteration, known as the Warburg effect, serves as a significant indicator of malignant tumor transformation. The Warburg effect primarily impacts cancer occurrence by influencing the aerobic glycolysis pathway in cancer cells. Key enzymes involved in this process include glucose transporters (GLUTs), HKs, PFKs, LDHs, and PKM2. Moreover, the expression of transcriptional regulatory factors and proteins, such as FOXM1, p53, NF-κB, HIF1α, and c-Myc, can also influence cancer progression. Furthermore, lncRNAs, miRNAs, and circular RNAs play a vital role in directly regulating the Warburg effect. Additionally, gene mutations, tumor microenvironment remodeling, and immune system interactions are closely associated with the Warburg effect. Notably, the development of drugs targeting the Warburg effect has exhibited promising potential in tumor treatment. This comprehensive review presents novel directions and approaches for the early diagnosis and treatment of cancer patients by conducting in-depth research and summarizing the bright prospects of targeting the Warburg effect in cancer.

METTL3 as a novel diagnosis and treatment biomarker and its association with glycolysis, cuproptosis and ceRNA in oesophageal carcinoma

METTL3 has been shown to be involved in regulating a variety of biological processes. However, the relationship between METTL3 expression and glycolysis, cuproptosis-related genes and the ceRNA network in oesophageal carcinoma (ESCA) remains unclear. ESCA expression profiles from databases were obtained, and target genes were identified using differential analysis and visualization. Immunohistochemistry (IHC) staining assessed METTL3 expression differences. Functional enrichment analysis using GO, KEGG and GSEA was conducted on the co-expression profile of METTL3. Cell experiments were performed to assess the effect of METTL3 interference on tumour cells. Correlation and differential analyses were carried out to assess the relationship between METTL3 with glycolysis and cuproptosis. qRT-PCR was used to validate the effects of METTL3 interference on glycolysis-related genes. Online tools were utilized to screen and construct ceRNA networks based on the ceRNA theory. METTL3 expression was significantly higher in ESCA compared to the controls. The IHC results were consistent with the above results. Enrichment analysis revealed that METTL3 is involved in multiple pathways associated with tumour development. Significant correlations were observed between METTL3 and glycolysis-related genes and cuproptosis-related gene. Experiments confirmed that interfered with METTL3 significantly inhibited glucose uptake and lactate production in tumour cells, and affected the expression of glycolytic-related genes. Finally, two potential ceRNA networks were successfully predicted and constructed. Our study establishes the association between METTL3 overexpression and ESCA progression. Additionally, we propose potential links between METTL3 and glycolysis, cuproptosis and ceRNA, presenting a novel targeted therapy strategy for ESCA.

Insights into the Roles of Epigenetic Modifications in Ferroptosis

Ferroptosis is a non-apoptotic mode of cell death driven by membrane lipid peroxidation and is characterized by elevated intracellular levels of Fe2+, ROS, and lipid peroxidation. Studies have shown that ferroptosis is related to the development of multiple diseases, such as cancer, neurodegenerative diseases, and acute myeloid leukemia. Ferroptosis plays a dual role in the occurrence and development of these diseases. Ferroptosis mainly involves iron metabolism, ROS, and lipid metabolism. Various mechanisms, including epigenetic regulation, have been reported to be deeply involved in ferroptosis. Abnormal epigenetic modifications have been reported to promote tumor onset or other diseases and resistance to chemotherapy drugs. In recent years, diversified studies have shown that epigenetic modification is involved in ferroptosis. In this review, we reviewed the current resistance system of ferroptosis and the research progress of epigenetic modification, such as DNA methylation, RNA methylation, non-coding RNAs, and histone modification in cancer and other diseases by regulating ferroptosis.

Glycolysis Induced by METTL14 Is Essential for Macrophage Phagocytosis and Phenotype in Cervical Cancer

N 6-methyladenosine (m6A) is the most abundant mRNA modification in mammals and it plays a vital role in various biological processes. However, the roles of m6A on cervical cancer tumorigenesis, especially macrophages infiltrated in the tumor microenvironment of cervical cancer, are still unclear. We analyzed the abnormal m6A methylation in cervical cancer, using CaSki and THP-1 cell lines, that might influence macrophage polarization and/or function in the tumor microenvironment. In addition, C57BL/6J and BALB/c nude mice were used for validation in vivo. In this study, m6A methylated RNA immunoprecipitation sequencing analysis revealed the m6A profiles in cervical cancer. Then, we discovered that the high expression of METTL14 (methyltransferase 14, N6-adenosine-methyltransferase subunit) in cervical cancer tissues can promote the proportion of programmed cell death protein 1 (PD-1)-positive tumor-associated macrophages, which have an obstacle to devour tumor cells. Functionally, changes of METTL14 in cervical cancer inhibit the recognition and phagocytosis of macrophages to tumor cells. Mechanistically, the abnormality of METTL14 could target the glycolysis of tumors in vivo and vitro. Moreover, lactate acid produced by tumor glycolysis has an important role in the PD-1 expression of tumor-associated macrophages as a proinflammatory and immunosuppressive mediator. In this study, we revealed the effect of glycolysis regulated by METTL14 on the expression of PD-1 and phagocytosis of macrophages, which showed that METTL14 was a potential therapeutic target for treating advanced human cancers.

METTL3/MALAT1/ELAVL1 Axis Promotes Tumor Growth in Ovarian Cancer

Background

Studies increasingly recognize the role of N6-methyladenosine (m6A) modification in cancer occurrence and development. METTL3 is a core catalytic subunit of m6A-modified methyltransferases complex, but its regulatory mechanism in ovarian cancer (OC) is not clear.

Methods

In this study, GEPIA 2.0 database was applied for expression analysis, survival analysis and correlation analysis for OC. Additionally, in vitro and in vivo assays were conducted to explore regulatory mechanisms of METTL3 in OC.

Results

We found that METTL3 and MALAT1 were significantly overexpressed in OC tissues and cells compared to normal ovarian tissues and cells. The proliferation rate of OC cells was reduced significantly after knocking down the expression of METTL3 or MALAT1. Subsequently, MALAT1 as oncogene was found to interact with METTL3 and was upregulated in OC tissues and cells. Silencing MALAT1 inhibited OC cell proliferation. Further studies indicated that METTL3 enhanced the stability of MALAT1 by promoting the m6A modification of MALAT1 and that ELAVL1 as a downstream binding protein significantly up-regulated MALAT1 expression.

Conclusion

In conclusion, METTL3 was a carcinogenic molecule that promoted the occurrence of OC. The potential mechanism of the carcinogenic effect of METTL3 was realized by enhancing the m6A modification of MALAT1 mRNA through RNA binding protein ELAVL1.

METTL16 suppressed the proliferation and cisplatin-chemoresistance of bladder cancer by degrading PMEPA1 mRNA in a m6A manner through autophagy pathway

N6-methyladenosine (m6A) is important in the physiological processes of many species. Methyltransferase-like 16 (METTL16) is a novel discovered m6A methylase, regulating various tumors in an m6A-dependent manner. However, its function in bladder cancer (BLCA) remains largely unclear. In the present study, we found that low expression of METTL16 predicted poor survival in BLCA patients. METTL16 inhibited the proliferation and cisplatin-resistance function of bladder cancer cells in vitro and in vivo. In addition, METTL16 reduced the mRNA stability of prostate transmembrane protein androgen induced-1 (PMEPA1) via binding to its m6A site in the 3'-UTR, thereby inhibited the proliferation of bladder cancer cells and increased the sensitivity of cisplatin through PMEPA1-mediated autophagy pathway. Finally, we found that hypoxia-inducible factor 2α (HIF-2α) exerted its tumor-promoting effect by binding the METTL16 promoter region to repress its transcription. Taken together, High expression of METTL16 predicted better survival in BLCA. METTL16 significantly inhibited bladder cancer cell proliferation and sensitized bladder cancer cells to cisplatin via HIF-2α-METTL16-PMEPA1-autophagy axis in a m6A manner. These findings might provide fresh insights into BLCA therapy.

Methyltransferase-like 3 mediated RNA m6 A modifications in the reproductive system: Potentials for diagnosis and therapy

Several studies have highlighted the functional indispensability of methyltransferase-like 3 (METTL3) in the reproductive system. However, a review that comprehensively interprets these studies and elucidates their relationships is lacking. Therefore, the present work aimed to review studies that have investigated the functions of METTL3 in the reproductive system (including spermatogenesis, follicle development, gametogenesis, reproductive cancer, asthenozoospermia and assisted reproduction failure). This review suggests that METTL3 functions not only essential for normal development, but also detrimental in the occurrence of disorders. In addition, promising applications of METTL3 as a diagnostic or prognostic biomarker and therapeutic target for reproductive disorders have been proposed. Collectively, this review provides comprehensive interpretations, novel insights, potential applications and future perspectives on the role of METTL3 in regulating the reproductive system, which may be a valuable reference for researchers and clinicians.

m6A reader IGF2BP2 promotes lymphatic metastasis by stabilizing DPP4 in papillary thyroid carcinoma

Lymph node metastasis (LNM) is a major cause of locoregional recurrence of papillary thyroid carcinoma (PTC). However, the mechanisms responsible for LNM are unclear. Aberrant N6-methyladenosine (m6A) RNA modification plays a vital role in cancer progression and metastasis, and whether m6A modification regulates LNM in PTC remains to be determined. This study showed that IGF2BP2 was upregulated in PTC and positively associated with LNM. Functionally, IGF2BP2 knockdown significantly inhibited PTC cell proliferation and invasion in vitro, and vice versa. Moreover, IGF2BP2 knockdown significantly inhibited lymphatic metastasis in vivo. Mechanistically, Human m6A epitranscriptomic microarray, MeRIP, and RIP assays demonstrated that IGF2BP2 activated the NF-KB pathway by enhancing DPP4 stability in an m6A-dependent manner. Furthermore, IGF2BP2 knockdown increased the sensitivity of PTC cells to cisplatin therapy to a certain extent, while its overexpression produced the opposite effects. Overall, this study uncovers that IGF2BP2 promotes lymphatic metastasis via stabilizing DPP4 in an m6A-dependent manner, and provides new insights for understanding the mechanism of lymphatic metastasis in PTC.

m6A-modified circARHGAP12 promotes the aerobic glycolysis of doxorubicin-resistance osteosarcoma by targeting c-Myc

Chemotherapy resistance accompanied by energy metabolism abnormality functions as one of the main reasons for treatment failure and poor prognosis. However, the function of N6-methyladenosine (m6A)-modified circular RNA (circRNA) on osteosarcoma (OS) is still unclear. Here, present research investigated the potential role and mechanism of circARHGAP12 on OS doxorubicin (Dox) resistance and aerobic glycolysis. Results indicated that circARHGAP12 was a novel m6A-modified circRNA, which was up-regulated in OS cells. Overexpression of circARHGAP12 promoted the Dox resistance half-maximal inhibitory concentration (IC50) and aerobic glycolysis (glucose uptake, lactate and ATP production) in OS cells (Saos-2/Dox, MG63/Dox). Mechanistically, m6A-modified circARHGAP12 could bind with c-Myc mRNA through m6A-dependent manner, thereby enhancing the c-Myc mRNA stability. Thus, these findings revealed the critical function of circARHGAP12 on OS Dox-resistance and aerobic glycolysis. Taken together, our study demonstrated a critical function of circARHGAP12 on OS chemotherapy resistance and energy metabolism abnormality, providing critical roles on OS treatment.

RNF20 Reduces Cell Proliferation and Warburg Effect by Promoting NLRP3 Ubiquitination in Liver Cancer

The present study explored that the effects and its possible mechanisms of ring finger protein 20 (RNF20) in Postoperative survival rate of liver cancer in clinical. All the serum samples were collected from our hospital. Quantitative polymerase chain reaction (PCR) and microarray analysis, and RNA pull down assay were used in this study. We found that the serum RNF20 mRNA expression level in patients with liver cancer were down-regulated. Postoperative survival rate of RNF20 high expression was higher than that of RNF20 low expression. Then, over-expression of RNF20 diminished liver cancer cell proliferation and metastasis. RNF20 reduced Warburg effect of liver cancer. RNF20 expression regulated NOD-like receptor protein 3 (NLRP3) expression and increased NLRP3 Ubiquitination. NLRP3 participated in the effects of RNF20 on cell proliferation, and not affected on Warburg effect of liver cancer. Our study demonstrated that the serum RNF20 expression level was down-regulated in liver cancer, and promoted postoperative survival rate. RNF20 can reduce cancer progression of liver cancer by NLRP3 signal pathway, suggesting that it may prove to be a potential therapeutic target for postoperative survival rate of liver cancer.

m6A-modified RIPK4 facilitates proliferation and cisplatin resistance in epithelial ovarian cancer

BACKGROUND

Cisplatin (DDP)-based chemotherapy is a common chemotherapeutic regimen for the treatment of advanced epithelial ovarian cancer (EOC). However, most patients rapidly develop chemoresistance. N6-methyladenosine (m6A) is a pervasive RNA modification, and its specific role and potential mechanism in the regulation of chemosensitivity in EOC remain unclear.

METHODS

The expression of RIPK4 and its clinicopathological impact were evaluated in EOC cohorts. The biological effects of RIPK4 were investigated using in vitro and in vivo models. RNA m6A quantification was used to measure total m6A levels in epithelial ovarian cancer cells. Luciferase reporter, MeRIP-qPCR, RIP-qPCR and actinomycin-D assays were used to investigate RNA/RNA interactions and m6A modification of RIPK4 mRNA.

RESULTS

We demonstrated that RIPK4, an upregulated mRNA in EOC, acts as an oncogene in EOC cells by promoting tumor cell proliferation and DDP resistance at the clinical, database, cellular, and animal model levels. Mechanistically, METTL3 facilitates m6A modification, and YTHDF1 recognizes the specific m6A-modified site to prevent RIPK4 RNA degradation and upregulate RIPK4 expression. This induces NF-κB activation, resulting in tumor growth and DDP resistance in vitro and in vivo.

CONCLUSIONS

Collectively, the present findings reveal a novel mechanism underlying the induction of DDP resistance by m6A-modified RIPK4, that may contribute to overcoming chemoresistance in EOC.

RNA m6A modifications regulate crosstalk between tumor metabolism and immunity

In recent years, m6A modifications in RNA transcripts have arisen as a hot topic in cancer research. Indeed, a number of independent studies have elaborated that the m6A modification impacts the behavior of tumor cells and tumor-infiltrating immune cells, altering tumor cell metabolism along with the differentiation and functional activity of immune cells. This review elaborates on the links between RNA m6A modifications, tumor cell metabolism, and immune cell behavior, discussing this topic from the viewpoint of reciprocal regulation through "RNA m6A-tumor cell metabolism-immune cell behavior" and "RNA m6A-immune cell behavior-tumor cell metabolism" axes. In addition, we discuss the various factors affecting RNA m6A modifications in the tumor microenvironment, particularly the effects of hypoxia associated with cancer cell metabolism along with immune cell-secreted cytokines. Our analysis proposes the conclusion that RNA m6A modifications support widespread interactions between tumor metabolism and tumor immunity. With the current viewpoint that long-term cancer control must tackle cancer cell malignant behavior while strengthening anti-tumor immunity, the recognition of RNA m6A modifications as a key factor provides a new direction for the targeted therapy of tumors. This article is categorized under: RNA Processing > RNA Editing and Modification RNA in Disease and Development > RNA in Disease RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.

YTHDF1 in Tumor Cell Metabolism: An Updated Review

With the advancement of research on m6A-related mechanisms in recent years, the YTHDF protein family within m6A readers has garnered significant attention. Among them, YTHDF1 serves as a pivotal member, playing a crucial role in protein translation, tumor proliferation, metabolic reprogramming of various tumor cells, and immune evasion. In addition, YTHDF1 also exerts regulatory effects on tumors through multiple signaling pathways, and numerous studies have confirmed its ability to assist in the reprogramming of the tumor cell-related metabolic processes. The focus of research on YTHDF1 has shifted in recent years from its m6A-recognition and -modification function to the molecular mechanisms by which it regulates tumor progression, particularly by exploring the regulatory factors that interact with YTHDF1 upstream and downstream. In this review, we elucidate the latest signaling pathway mechanisms of YTHDF1 in various tumor cells, with a special emphasis on its distinctive characteristics in tumor cell metabolic reprogramming. Furthermore, we summarize the latest pathological and physiological processes involving YTHDF1 in tumor cells, and analyze potential therapeutic approaches that utilize YTHDF1. We believe that YTHDF1 represents a highly promising target for future tumor treatments and a novel tumor biomarker.

The Promoting Role of HK II in Tumor Development and the Research Progress of Its Inhibitors

Increased glycolysis is a key characteristic of malignant cells that contributes to their high proliferation rates and ability to develop drug resistance. The glycolysis rate-limiting enzyme hexokinase II (HK II) is overexpressed in most tumor cells and significantly affects tumor development. This paper examines the structure of HK II and the specific biological factors that influence its role in tumor development, as well as the potential of HK II inhibitors in antitumor therapy. Furthermore, we identify and discuss the inhibitors of HK II that have been reported in the literature.

Upregulation of FAM83F by c-Myc promotes cervical cancer growth and aerobic glycolysis via Wnt/β-catenin signaling activation

Cervical cancer (CC) seriously affects women's health. Therefore, elucidation of the exact mechanisms and identification of novel therapeutic targets are urgently needed. In this study, we identified FAM83F, which was highly expressed in CC cells and tissues, as a potential target. Our clinical data revealed that FAM83F protein expression was markedly elevated in CC tissues and was positively correlated with poor prognosis. Moreover, we observed that FAM83F knockdown significantly inhibited cell proliferation, induced apoptosis, and suppressed glycolysis in CC cells, while its overexpression displayed opposite effects. Mechanistically, FAM83F regulated CC cell growth and glycolysis by the modulation of Wnt/β-catenin pathway. The enhancing effects of FAM83F overexpression on CC cell proliferation and glycolysis could be impaired by the Wnt/β-catenin inhibitor XAV939. Moreover, we found that c-Myc bound to the FAM83F promoter and activated the transcription of FAM83F. Notably, knockdown of FAM83F impaired the enhancement of cell proliferation and glycolysis induced by ectopic c-Myc. Consistent with in vitro findings, results from a xenograft mouse model confirmed the promoting role of FAM83F. In summary, our study demonstrated that FAM83F promoted CC growth and glycolysis through regulating the Wnt/β-catenin pathway, suggesting that FAM83F may be a potential molecular target for CC treatment. Schematic summary of c-Myc-activated FAM83F transcription to promote cervical cancer growth and glycolysis by targeting the Wnt/β-catenin signal pathway.

RNA N6-methyladenosine-modified-binding protein YTHDF1 promotes prostate cancer progression by regulating androgen function-related gene TRIM68

PURPOSE

There is no report about the direct relationship between m6A modification and androgen receptor (AR)-related genes in prostate cancer (PC). We aimed to study the mechanisms of m6A methylation in regulating the pathogenesis of PC from the perspective of AR-related genes.

METHODS

qRT-PCR was applied to detect the expression of m6A-related genes in PC cell with or without AR inhibitor. The effects of YTHDF1 knockdown on PC cell viability, apoptosis, migration and invasion were investigated using flow cytometry, wound healing and transwell assays, respectively. The mechanism of YTHDF1 action was investigated using m6A RNA immunoprecipitation (MeRIP) sequencing. The biological functions of YTHDF1 were also explored through in vivo experiments.

RESULTS

YTHDF1 was significantly down-regulated in AR inhibitor group. YTHDF1 knockdown significantly decreased AR level, viability and m6A methylation level of PC cells. TRIM68 was identified as a direct target of YTHDF1. Both YTHDF1 and TRIM68 knockdown increased apoptosis, and decreased cell viability, migration, and invasion of PC cells, while TRIM68 overexpression reversed the effects of YTHDF1 knockdown on PC cells. In addition, knockdown of YTHDF1 or TRIM68 significantly decreased the m6A methylation level, and mRNA and protein levels of YTHDF1, TRIM68 and AR in PC cells, while TRIM68 overexpression increased the expression levels above. Furthermore, subcutaneous xenografts of nude mice also revealed that TRIM68 could reverse the effects of YTHDF1 knockdown in PC in vivo.

CONCLUSION

This study suggested the key role of YTHDF1-mediated m6A modification in PC progression by regulating androgen function-related gene TRIM68 in PC.

The effect on m6A methylation writer complex by the reduced MATR3 in pterygium

Pterygium is a common eye surface disease with high recurrence and unclear pathogenesis. In current study, RNA sequencing was conducted in 6 pairs of human pterygium and conjunctival tissues, and Matr3 as a novel candidate gene was significantly reduced in pterygium compared to control tissues. Moreover, immunoprecipitation was performed to pull down MATR3, and WTAP specially interacting with MATR3 in control but not pterygium was identified by mass spectrum. Immunoprecipitation was performed to validate the interaction between MATR3 and WTAP/METTL3/METTL14 complex. (Methylated) RNA immunoprecipitation was performed to further reveal that the binding affinity of WTAP and MATR3 was lost at 3' UTR of RNA molecules of down-regulated genes in pterygium. Overall, we figured out the loss of intercrossing between MATR3 and N6-methyladenosine methyltransferase complex, as well as indicated the potential impact on transcription of target genes in pterygium.

NR1H4-mediated circRHOBTB3 modulates the proliferation, metastasis, and Warburg effects of cervical cancer through interacting with IGF2BP3

Globally, cervical cancer (CC) ranks as the fourth most common cancer and the most lethal malignancy among females of reproductive age. The incidence of CC is increasing in low-income countries, with unsatisfactory outcomes and long-term survival for CC patients. Circular RNAs (CircRNAs) are promising therapeutics that target multiple cancers. In this study, we investigated the tumorigenic role of circRHOBTB3 in CC, showing that circRHOBTB3 is highly expressed in CC cells and circRHOBTB3 knockdown also repressed CC proliferation, migration, invasion, and the Warburg effects. CircRHOBTB3 interacted with the RNA-binding protein, IGF2BP3, to stabilize its expression in CC cells and is putatively transcriptionally regulated by NR1H4. In conclusion, this novel NR1H4/circRHOBTB3/IGF2BP3 axis may provide new insights into CC pathogenesis.

Cancer metastasis under the magnifying glass of epigenetics and epitranscriptomics

Most of the cancer-associated mortality and morbidity can be attributed to metastasis. The role of epigenetic and epitranscriptomic alterations in cancer origin and progression has been extensively demonstrated during the last years. Both regulations share similar mechanisms driven by DNA or RNA modifiers, namely writers, readers, and erasers; enzymes responsible of respectively introducing, recognizing, or removing the epigenetic or epitranscriptomic modifications. Epigenetic regulation is achieved by DNA methylation, histone modifications, non-coding RNAs, chromatin accessibility, and enhancer reprogramming. In parallel, regulation at RNA level, named epitranscriptomic, is driven by a wide diversity of chemical modifications in mostly all RNA molecules. These two-layer regulatory mechanisms are finely controlled in normal tissue, and dysregulations are associated with every hallmark of human cancer. In this review, we provide an overview of the current state of knowledge regarding epigenetic and epitranscriptomic alterations governing tumor metastasis, and compare pathways regulated at DNA or RNA levels to shed light on a possible epi-crosstalk in cancer metastasis. A deeper understanding on these mechanisms could have important clinical implications for the prevention of advanced malignancies and the management of the disseminated diseases. Additionally, as these epi-alterations can potentially be reversed by small molecules or inhibitors against epi-modifiers, novel therapeutic alternatives could be envisioned.

METTL14-m6A-FOXO3a axis regulates autophagy and inflammation in ankylosing spondylitis

The role of m6A in ankylosing spondylitis (AS) remains largely obscure. In this study, we found that m6A modification was decreased in T cells of AS, and the abnormal m6A modification was attributed to the downregulation of methyltransferase-like 14 (METTL14). METTL14 exerted a critical role in regulating autophagy activity and inflammation via targeting Forkhead box O3a (FOXO3a). Mechanistically, the loss of METTL14 decreased the expression of FOXO3a, leading to the damage of autophagic flux and the aggravation of inflammation. Inversely, the forced expression of METTL14 upregulated the expression of FOXO3a, thereby activating autophagy and alleviating inflammation. Furthermore, our results revealed that METTL14 targeted FOXO3a mRNA and regulated its expression and stability in a m6A-dependent manner. These findings uncovered the functional importance of m6A methylation mechanisms in the regulation of autophagy and inflammation, which expanded our understanding of this interaction and was critical for the development of therapeutic strategies for AS.

The roles of m6A methylation in cervical cancer: functions, molecular mechanisms, and clinical applications

Cervical cancer (CC) is a gynecological neoplasm with the highest incidence rate, primarily attributed to the persistent infection of high-risk Human papillomavirus (HPV). Despite extensive research, the pathogenesis of CC remains unclear. N6-methyladenosine (m6A) methylation, the most prevalent form of epigenetic modification in RNA, is intricately linked to cell proliferation, metastasis, metabolism, and therapeutic resistance within the tumor microenvironment (TME) of CC. The involvement of the writer, reader, and eraser in m6A modification impacts the advancement of tumors through the regulation of RNA stability, nuclear export, translation efficiency, and RNA degradation. Here, we discuss the biogenesis of m6A, the atypical expressions of m6A regulators, the mechanisms of molecular interactions, and their functions in CC. Furthermore, we elucidate m6A modification of non-coding RNA. In the context of precision medicine, and with the advancements of genomics, proteomics, and high-throughput sequencing technologies, we summarize the application of m6A in the clinical diagnosis and treatment of CC. Additionally, new perspectives on detection methods, immune regulation, and nano-drug development are presented, which lay the foundation for further research of m6A and provide new ideas for the clinical treatment of CC.

DCLRE1B promotes tumor progression and predicts immunotherapy response through METTL3-mediated m6A modification in pancreatic cancer

BACKGROUND

DCLRE1B is a 5'-to-3' exonuclease, which is involved in repairing ICL-related DNA damage. DCLRE1B has been reported to cause poor prognosis in a variety of cancers. Nonetheless, there is no research on DCLRE1B's biological role in pan-cancer datasets. Thus, ascertaining the processes via which DCLRE1B modulates tumorigenesis was the goal of the extensive bioinformatics investigation of pan-cancer datasets in the present research.

METHODS

In our research, employing internet websites and databases including TIMER, GEPIA, TISIDB, Kaplan-Meier Plotter, SangerBox, cBioPortal, and LinkedOmics, DCLRE1B-related data in numerous tumors were extracted. To ascertain the association among DCLRE1B expression, prognosis, genetic changes, and tumor immunity, the pan-cancer datasets were examined. The DCLRE1B's biological roles in pancreatic cancer cells were ascertained by employing wound healing, in vitro CCK-8, and MeRIP-qPCR assays.

RESULT

According to the pan-cancer analysis, in numerous solid tumors, DCLRE1B upregulation was observed. Expression of DCLRE1B was found to be substantially related to the cancer patients' prognoses. Similarly, expression of DCLRE1B exhibited substantial association with immune cells in several cancer types. DCLRE1B expression correlated with immune checkpoint (ICP) gene expression and impacted immunotherapy sensitivity. According to in vitro trials, DCLRE1B promoted PC cells' proliferation and migration capacities. Also, according to GSEA enrichment analysis, DCLRE1B might participate in the JAK-STAT signaling pathway, which was confirmed by western blotting. In addition, we also found that the downregulation of DCLRE1B may be regulated by METTL3-mediated m6A modification.

CONCLUSIONS

In human cancer, the overexpression of DCLRE1B was generally observed, which aided cancer onset and advancement via a variety of processes comprising control of the immune cells' tumor infiltration. According to this study's findings, in a few malignant tumors, DCLRE1B is a candidate immunotherapeutic and prognostic biomarker.

N4-acetylcytidine-dependent GLMP mRNA stabilization by NAT10 promotes head and neck squamous cell carcinoma metastasis and remodels tumor microenvironment through MAPK/ERK signaling pathway

N4-acetylcytidine (ac4C) is a post-transcriptional RNA modification that regulates in various important biological processes. However, its role in human cancer, especially lymph node metastasis, remains largely unknown. Here, we demonstrated N-Acetyltransferase 10 (NAT10), as the only known "writer" of ac4C mRNA modification, was highly expressed in head and neck squamous cell carcinoma (HNSCC) patients with lymph node metastasis. High NAT10 levels in the lymph nodes of patients with HNSCC patients are a predictor of poor overall survival. Moreover, we found that high expression of NAT10 was positively upregulated by Nuclear Respiratory Factor 1 (NRF1) transcription factor. Gain- and loss-of-function experiments displayed that NAT10 promoted cell metastasis in mice. Mechanistically, NAT10 induced ac4C modification of Glycosylated Lysosomal Membrane Protein (GLMP) and stabilized its mRNA, which triggered the activation of the MAPK/ERK signaling pathway. Finally, the NAT10-specific inhibitor, remodelin, could inhibit HNSCC tumorigenesis in a 4-Nitroquinoline 1-oxide (4NQO)-induced murine tumor model and remodel the tumor microenvironment, including angiogenesis, CD8+ T cells and Treg recruitment. These results demonstrate that NAT10 promotes lymph node metastasis in HNSCC via ac4C-dependent stabilization of the GLMP transcript, providing a potential epitranscriptomic-targeted therapeutic strategy for HNSCC.

Establishment of a new molecular subtyping and prognostic signature with m6A/m5C/m1A/m7G regulatory genes for hepatocellular carcinoma

Background

RNA modification, including m6A, m5C, m1A, and m7G, participated in tumor progress. Therefore, the purpose of the present study was to explore the role of m6A/m5C/m1A/m7G regulatory genes in the prognosis and tumor microenvironment (TME) for hepatocellular carcinoma (HCC).

Methods

71 m6A/m5C/m1A/m7G regulatory genes expression for HCC was detected, differentially expressed genes were screened, and molecular forms were classified by unsupervised consensus clustering. Cox regression and the Least Absolute Shrinkage and Selection Operator (LASSO) analysis were applied to establish a prognostic signature. Time-dependent receiver operating characteristic (ROC) curves were evaluated for clinical effectiveness and accuracy of the prognostic hazard model. In cluster subtypes and risk models, the differences in prognosis, immune cell infiltration, immune checkpoint, immunotherapy, and drug sensitivity between different subtypes were evaluated.

Results

HCC patients were classified into two clusters (cluster 1 and cluster 2) according to the expression of 71 m6A/m5C/m1A/m7G regulatory genes. Cluster 1 had a poor prognosis and different immune cell infiltration. Cluster 1 had higher immune checkpoint expression and TIDE score than cluster 2. Subsequently, we construct a five-gene prognostic model of m6A/m5C/m1A/m7G regulatory genes (YTHDF2, YTHDF1,YBX1, TRMT61A, TRMT10C). The Kaplan-Meier and ROC curve analysis showed that the prognostic signature exhibited good predictability. The risk score was considered an independent poor prognostic index. The high-risk group had higher immune checkpoint expression and higher TIDE scores. 5-Fluorouracil, docetaxel, doxorubicin, etoposide, gemcitabine, paclitaxel, sorafenib, and vinblastine were more suitable for high-risk patients. ECM receptor interaction, cell cycle, and Leishmania infection were enriched in the high-risk group.

Conclusion

The clustering subgroups and prognostic model of m6A/m5C/m1A/m7G regulatory genes were linked with bad prognosis and TME for HCC, and had the potential to be a novel tool to evaluate the outcomes of HCC patients.

The emerging role of m6A modification of non-coding RNA in gastrointestinal cancers: a comprehensive review

Gastrointestinal (GI) cancer is a series of malignant tumors with a high incidence globally. Although approaches for tumor diagnosis and therapy have advanced substantially, the mechanisms underlying the occurrence and progression of GI cancer are still unclear. Increasing evidence supports an important role for N6-methyladenosine (m6A) modification in many biological processes, including cancer-related processes via splicing, export, degradation, and translation of mRNAs. Under distinct cancer contexts, m6A regulators have different expression patterns and can regulate or be regulated by mRNAs and non-coding RNAs, especially long non-coding RNAs. The roles of m6A in cancer development have attracted increasing attention in epigenetics research. In this review, we synthesize progress in our understanding of m6A and its roles in GI cancer, especially esophageal, gastric, and colorectal cancers. Furthermore, we clarify the mechanism by which m6A contributes to GI cancer, providing a basis for the development of diagnostic, prognostic, and therapeutic targets.

HPV E7-drived ALKBH5 promotes cervical cancer progression by modulating m6A modification of PAK5

Human papillomavirus (HPV) infection is a causative agent of cervical cancer (CC). N6-methyladenosine (m6A) modification is implicated in carcinogenesis and tumor progression. However, the involvement of m6A modification in HPV-involved CC remains unclear. Here we showed that HPV E6/7 oncoproteins affected the global m6A modification and E7 specifically promoted the expression of ALKBH5. We found that ALKBH5 was significantly upregulated in CC and might serve as a valuable prognostic marker. Forced expression of ALKBH5 enhanced the malignant phenotypes of CC cells. Mechanistically, we discovered that E7 increased ALKBH5 expression through E2F1-mediated activation of the H3K27Ac and H3K4Me3 histone modifications, as well as post-translational modification mediated by DDX3. ALKBH5-mediated m6A demethylation enhanced the expression of PAK5. The m6A reader YTHDF2 bound to PAK5 mRNA and regulated its stability in an m6A-dependent manner. Moreover, ALKBH5 promoted tumorigenesis and metastasis of CC by regulating PAK5. Overall, our findings herein demonstrate a significant role of ALKBH5 in CC progression in HPV-positive cells. Thus, we propose that ALKBH5 may serve as a prognostic biomarker and therapeutic target for CC patients.

m6A-regulated tumor glycolysis: new advances in epigenetics and metabolism

Glycolytic reprogramming is one of the most important features of cancer and plays an integral role in the progression of cancer. In cancer cells, changes in glucose metabolism meet the needs of self-proliferation, angiogenesis and lymphangiogenesis, metastasis, and also affect the immune escape, prognosis evaluation and therapeutic effect of cancer. The n6-methyladenosine (m6A) modification of RNA is widespread in eukaryotic cells. Dynamic and reversible m6A modifications are widely involved in the regulation of cancer stem cell renewal and differentiation, tumor therapy resistance, tumor microenvironment, tumor immune escape, and tumor metabolism. Lately, more and more evidences show that m6A modification can affect the glycolysis process of tumors in a variety of ways to regulate the biological behavior of tumors. In this review, we discussed the role of glycolysis in tumor genesis and development, and elaborated in detail the profound impact of m6A modification on different tumor by regulating glycolysis. We believe that m6A modified glycolysis has great significance and potential for tumor treatment.

Methyltransferase-like proteins in cancer biology and potential therapeutic targeting

RNA modification has recently become a significant process of gene regulation, and the methyltransferase-like (METTL) family of proteins plays a critical role in RNA modification, methylating various types of RNAs, including mRNA, tRNA, microRNA, rRNA, and mitochondrial RNAs. METTL proteins consist of a unique seven-beta-strand domain, which binds to the methyl donor SAM to catalyze methyl transfer. The most typical family member METTL3/METTL14 forms a methyltransferase complex involved in N6-methyladenosine (m6A) modification of RNA, regulating tumor proliferation, metastasis and invasion, immunotherapy resistance, and metabolic reprogramming of tumor cells. METTL1, METTL4, METTL5, and METTL16 have also been recently identified to have some regulatory ability in tumorigenesis, and the rest of the METTL family members rely on their methyltransferase activity for methylation of different nucleotides, proteins, and small molecules, which regulate translation and affect processes such as cell differentiation and development. Herein, we summarize the literature on METTLs in the last three years to elucidate their roles in human cancers and provide a theoretical basis for their future use as potential therapeutic targets.

The roles and implications of RNA m6A modification in cancer

N6-Methyladenosine (m6A), the most prevalent internal modification in eukaryotic mRNA, has been extensively and increasingly studied over the past decade. Dysregulation of RNA m6A modification and its associated machinery, including writers, erasers and readers, is frequently observed in various cancer types, and the dysregulation profiles might serve as diagnostic, prognostic and/or predictive biomarkers. Dysregulated m6A modifiers have been shown to function as oncoproteins or tumour suppressors with essential roles in cancer initiation, progression, metastasis, metabolism, therapy resistance and immune evasion as well as in cancer stem cell self-renewal and the tumour microenvironment, highlighting the therapeutic potential of targeting the dysregulated m6A machinery for cancer treatment. In this Review, we discuss the mechanisms by which m6A modifiers determine the fate of target RNAs and thereby influence protein expression, molecular pathways and cell phenotypes. We also describe the state-of-the-art methodologies for mapping global m6A epitranscriptomes in cancer. We further summarize discoveries regarding the dysregulation of m6A modifiers and modifications in cancer, their pathological roles, and the underlying molecular mechanisms. Finally, we discuss m6A-related prognostic and predictive molecular biomarkers in cancer as well as the development of small-molecule inhibitors targeting oncogenic m6A modifiers and their activity in preclinical models.