A novel inhibitor of N 6-methyladenosine demethylase FTO induces mRNA methylation and shows anti-cancer activities

Epigenetic targets and their inhibitors in the treatment of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a deadly lung disease characterized by fibroblast proliferation, excessive extracellular matrix buildup, inflammation, and tissue damage, resulting in respiratory failure and death. Recent studies suggest that impaired interactions among epithelial, mesenchymal, immune, and endothelial cells play a key role in IPF development. Advances in bioinformatics have also linked epigenetics, which bridges gene expression and environmental factors, to IPF. Despite the incomplete understanding of the pathogenic mechanisms underlying IPF, recent preclinical studies have identified several novel epigenetic therapeutic targets, including DNMT, EZH2, G9a/GLP, PRMT1/7, KDM6B, HDAC, CBP/p300, BRD4, METTL3, FTO, and ALKBH5, along with potential small-molecule inhibitors relevant for its treatment. This review explores the pathogenesis of IPF, emphasizing epigenetic therapeutic targets and potential small molecule drugs. It also analyzes the structure-activity relationships of these epigenetic drugs and summarizes their biological activities. The objective is to advance the development of innovative epigenetic therapies for IPF.

Cold atmospheric plasma control metabolic syndromes via targeting fat mass and obesity-associated protein

Both obesity and metabolic disorders are global medical problems. Driven by prolonged inflammation, obesity increases the risk of developing metabolic syndromes such as fatty liver, diabetes, cardiovascular diseases and cancers. The fat mass and obesity-associated protein (FTO) is an m6A demethylase, elevated activity of which is known to promote the pathogenesis of many metabolic disorders, leading to the establishment of various FTO inhibitors. By combing through intrinsic connections among obesity and the four primary metabolic problems, we attribute their shared pathological cause to prolonged inflammation. By reviewing the roles of FTO in promoting these disorders and the current status of existing FTO inhibitors in treating these syndromes, we underpinned the paramount potential of resolving these clinical issues by targeting FTO and the urgent need of establishing novel FTO inhibitors with maximized efficacy and minimized side effect. Cold atmospheric plasma (CAP) is the fourth state of matter with demonstrated efficacy in treating various diseases associated with chronic inflammation. By introducing the medical characteristics of CAP, we proposed it as a possible solution to unresolved issues of current FTO inhibitors given its anti-inflammation feature and demonstrated clinical safety. We also emphasized the need of intensive investigations in exploring the feasibility of using CAP in treating obesity and associated metabolic syndromes that might function through targeting FTO.

Role and mechanisms of m6A demethylases in digestive system tumors

Digestive system tumors are common malignancies in humans, often accompanied by high mortality and poor prognosis. Therefore, intensive research on the pathogenesis of digestive system tumors is imperative. N6-methyladenosine (m6A) is the most common RNA modification in eukaryotes and exerts regulatory effects on RNA expression and metabolism, including splicing, translation, stability, decay, and transport. m6A demethylases belong to the AlkB family of dioxygenases that can catalyze m6A demethylation. Accumulating evidence in recent years has shown that abnormal m6A levels caused by m6A demethylases play crucial roles in different aspects of human cancer development. In this review, we comprehensively summarize the recent findings on the functions and underlying molecular mechanisms of m6A demethylases in cell proliferation, apoptosis, migration, invasion, metastasis, angiogenesis, resistance to chemo- and radiotherapy, and the tumor immune microenvironment (TIME) of digestive system tumors. Furthermore, we discuss the therapeutic potential of targeting these m6A demethylases for treatment.

RNA modifications in the tumor microenvironment: insights into the cancer-immunity cycle and beyond

The chemical modification of biological molecules is a critical regulatory mechanism for controlling molecular functions. Although research has long focused on DNA and proteins, RNA modifications have recently attracted substantial interest with the advancement in detection technologies. In oncology, many studies have identified dysregulated RNA modifications including m6A, m1A, m5C, m7G, pseudouridylation and A to I editing, leading to disrupted downstream pathways. As the concept of the tumor microenvironment has gained prominence, studies have increasingly examined the role of RNA modifications in this context, focusing on interactions among cancer cells, immune cells, stromal cells, and other components. Here we review the RNA modifications in the tumor microenvironment through the perspective of the Cancer-Immunity Cycle. The extracellular RNA modifications including exosomes and influence of microbiome in RNA modifications are potential research questions. Additionally, RNA modifying enzymes including FTO, ALKBH5, METTL3, PUS7 are under investigation as potential biomarkers and targets for combination with immunotherapies. ADCs and mimetics of modified RNA could be potential novel drugs. This review discusses the regulatory roles of RNA modifications within the tumor microenvironment.

Discovery of maleimide derivatives as m6A demethylase ALKBH5 inhibitors

Human AlkB homologue H5 (ALKBH5) is a crucial demethylase for N6-methyladenosine (m6A) of mRNA. Although ALKBH5 is recognized as a promising target in various cancers, especially acute myeloid leukemia (AML), research on inhibitors of ALKBH5 remains limited. Here, we reported the discovery of a series of maleimide-based small molecule inhibitors of ALKBH5, resulting in the identification of compound 18 through optimization. Comprehensive evaluations suggested that compound 18 holds significant potential as a lead compound for ALKBH5 inhibitor.

Regulation and application of m6A modification in tumor immunity

The m6A modification is an RNA modification that impacts various processes of RNA molecules, including transcription, splicing, stability, and translation. Recently, researchers have discovered that the presence of m6A modification can influence the interaction between tumor cells and immune cells and also play a role in regulating the expression of immune response-related genes. Additionally, m6A modification is intricately involved in the regulation of tumor immune evasion and drug resistance. Specifically, certain tumor cells can manipulate the gene expression through m6A modification to evade immune system attacks. Therefore, it might be possible to enhance tumor immune surveillance and improve the effectiveness of immune-based therapies by manipulating m6A modification. This review systematically discusses the role of m6A modification in tumor immunity, specifically highlighting its regulation of immune cells and immune-related genes in tumor cells. Furthermore, we explore the potential of m6A modification inhibitors as anti-cancer therapies and the significance of m6A regulatory factors in predicting the efficacy of tumor immune therapy.

Research progress on N6-Methyladenosine modification in angiogenesis, vasculogenic mimicry, and therapeutic implications in breast cancer

N6-methyladenosine (m6A) modification is the most common epitranscriptomic modification in eukaryotic RNA and has garnered extensive attention in the context of breast cancer research. The m6A modification significantly impacts tumorigenesis and tumor progression by regulating RNA stability, splicing, translation, and degradation. In this review we summarize recent advances in understanding the roles of m6A modification in the mechanisms underlying angiogenesis and vasculogenic mimicry in breast cancer. We review how m6A modification and associated transcripts influence relevant factors by affecting key factors and signaling pathways, highlighting the interactions among m6A "writers," "erasers," and "readers," and their overall impact on tumor angiogenesis and vasculogenic mimicry, as well as potential new therapeutic targets.

Discovery of the salicylaldehyde-based compound DDO-02267 as a lysine-targeting covalent inhibitor of ALKBH5

N6-methyladenosine (m6A) is a crucial mRNA epigenetic modification in eukaryotes, and its methylation regulation is associated with the proliferation and metastasis of diverse tumor cells. ALKBH5 functions as a demethylase for m6A and plays a role in the demethylation process, thus influencing tumor cell growth and migration. However, there are limited reports on selective small molecule inhibitors of ALKBH5. Herein, we designed and synthesized the ALKBH5 covalent inhibitor DDO-02267 by analyzing the protein structure of ALKBH5 and introducing salicylaldehyde warhead into noncovalent small molecule ligand. DDO-02267 specifically targeted Lys132 within ALKBH5, demonstrating significant selectivity for ALKBH5 in vitro. Additionally, DDO-02267 increased m6A levels and targeted the ALKBH5-AXL signaling axis in AML cells. The compound DDO-02267 can serve as a probe for investigating the biological function of mRNA demethylase and may inspire the development of future ALKBH5 inhibitors.

Discovery of Novel RNA Demethylase FTO Inhibitors Featuring an Acylhydrazone Scaffold with Potent Antileukemia Activity

Fat mass obesity-associated protein (FTO) has been emerging as a potential therapeutic target for drug discovery in RNA epigenetics. In this work, a series of novel FTO inhibitors featuring an acylhydrazone scaffold were identified, and the optimized compounds 8t-v showed potent FTO inhibitory activities with IC50 values ranging from 7.1 to 9.4 μM. FTO inhibitor 8t, as the lead compound, exhibited potent antiproliferative capacities against MOLM13, NB4, and THP-1 with IC50 values of 0.35, 0.59, and 0.70 μM, respectively, and remarkably induced NB4 cell apoptosis. Compound 8t also inhibited the FTO demethylation, enhanced the abundance of m6A, stabilized FTO protein folding, and regulated the oncogenic FTO signaling pathway. Importantly, compound 8t significantly caused a tumor volume reduction and tumor weight loss with a tumor growth inhibition (TGI) value of 51% in NB4 xenograft mice. Overall, our work provided valuable lead compounds for FTO inhibitors featuring an acylhydrazone scaffold with potent antileukemia activity both in vitro and in vivo.

Epitranscriptomics in the Glioma Context: A Brief Overview

Epitranscriptomics, the study of chemical modifications in RNA, has emerged as a crucial field in cellular regulation, adding another layer to the established landscape of DNA- and histone-based epigenetics. A wide range of RNA modifications, including N6-methyladenosine, pseudouridine, and inosine, have been identified across nearly all RNA species, influencing essential processes such as transcription, splicing, RNA stability, and translation. In the context of brain tumors, particularly gliomas, specific epitranscriptomic signatures have been reported to play a role in tumorigenesis. Despite growing evidence, the biological implications of various RNA modifications remain poorly understood. This review offers an examination of the main RNA modifications, the interplay between modified and unmodified molecules, how they could contribute to glioma-like phenotypes, and the therapeutic impact of targeting these mechanisms.

RNA modifications in cancer

RNA modifications are emerging as critical cancer regulators that influence tumorigenesis and progression. Key modifications, such as N6-methyladenosine (m6A) and 5-methylcytosine (m5C), are implicated in various cellular processes. These modifications are regulated by proteins that write, erase, and read RNA and modulate RNA stability, splicing, translation, and degradation. Recent studies have highlighted their roles in metabolic reprogramming, signaling pathways, and cell cycle control, which are essential for tumor proliferation and survival. Despite these scientific advances, the precise mechanisms by which RNA modifications affect cancer remain inadequately understood. This review comprehensively examines the role RNA modifications play in cancer proliferation, metastasis, and programmed cell death, including apoptosis, autophagy, and ferroptosis. It explores their effects on epithelial-mesenchymal transition (EMT) and the immune microenvironment, particularly in cancer metastasis. Furthermore, RNA modifications' potential in cancer therapies, including conventional treatments, immunotherapy, and targeted therapies, is discussed. By addressing these aspects, this review aims to bridge current research gaps and underscore the therapeutic potential of targeting RNA modifications to improve cancer treatment strategies and patient outcomes.

Recent advances in noncoding RNA modifications of gastrointestinal cancer

Elucidating the mechanisms underlying cancer development and proliferation is important for the development of therapeutic methods for the complete cure of cancer. In particular, the identification of diagnostic markers for early detection and new therapeutic strategies for refractory gastrointestinal cancers are needed. Various abnormal phenomena occur in cancer cells, such as functional changes of proteins, led by genomic mutations, and changes in gene expression due to dysregulation of epigenetic regulation. This is no exception for noncoding RNA (ncRNA), which do not encode proteins. Recent reports have revealed that microRNA (miRNA), long noncoding RNA (lncRNA), and circular RNA (circRNA) are deeply involved in cancer progression. These ncRNAs have attracted attention as gene expression regulatory molecules. Recent advances in technology have made it possible not only to read DNA and RNA sequences but also to study the modification state of each base. In particular, comprehensive analysis of N6-methyladenosine (m6A) has been performed by many research groups, with multiple studies reporting that m6A modifications of specific genes are associated with cancer progression. Based on the above, this review examines how ncRNA modifications are related to cancer progression in gastrointestinal cancers such as colorectal and pancreatic cancer. We also discuss enzyme inhibitors that have been reported to have drug discovery potential targeting m6A modifications. By utilizing the new perspective of ncRNA modification, we may be able to accumulate knowledge on the molecular biology of cancer and contribute to human health through diagnosis and treatment.

Bibliometric analysis and visualization of the research on the relationship between RNA methylation and immune cell infiltration in tumors

Background

This research endeavors to delve into the research hotspots and trends concerning RNA methylation and tumor immune cells through the application of bibliometric analysis and visualization techniques.

Methods

A comprehensive search in WoSCC (2014-2023) for RNA methylation and tumor immune cell articles/reviews was conducted. Bibliometric analysis and visualization employed CiteSpace, Bibliometric, and VOSviewer tools.

Results

A total of 3295 articles were included in the analysis, with a continuously increasing number of publications linking RNA methylation to tumoral immune cells. Chinese authors and research institutions have demonstrated a sustained growth trend in both the number of publications and author influence. SUN YAT SEN UNIVERSITY, a Chinese institution, has published the highest number of articles in this field, while also demonstrating extensive international and inter-institutional collaborations. Meanwhile, HARVARD UNIVERSITY has also achieved impressive results. For instance, Frontiers in Immunology has published the largest number of articles in this category. Nature Communications has published articles that are most influential in this field, playing a pivotal role in disseminating research findings. The sustained vitality of this field is attributed to its solid research foundation, including the groundbreaking work published by Professor Chiappinelli KB in Cell and the widely cited paper by Professor Han DL in Nature. Analysis of research trend topics reveals that m5C, immunotherapy, and the immune microenvironment are current research focuses.

Conclusion

Future investigative efforts at the juncture of RNA methylation and tumor immune cells are anticipated to concentrate on domains including m5C, n7-methylguanosine, cuproptosis, prognosis assessment, immunotherapeutic strategies, and the tumor microenvironment.

FTO promotes gefitinib-resistance by enhancing PELI3 expression and autophagy in non-small cell lung cancer

The established recognition of N6-methyladenosine (m6A) modification as an indispensable regulatory agent in human cancer is widely accepted. However, the understanding of m6A's role and the mechanisms underlying its contribution to gefitinib resistance is notably limited. Herein, using RT-qPCR, Western blot, Cell proliferation and apoptosis, as well as RNA m6A modification assays, we substantiated that heightened FTO (Fat Mass and Obesity-associated protein) expression substantially underpins the emergence of gefitinib resistance in NSCLC cells. This FTO-driven gefitinib resistance is hinged upon the co-occurrence of PELI3 (Pellino E3 Ubiquitin Protein Ligase Family Member 3) expression and concurrent autophagy activation. Manipulation of PELI3 expression and autophagy activation, including its attenuation, was efficacious in both inducing and overcoming gefitinib resistance within NSCLC cells, as validated in vitro and in vivo. In summary, this study has successfully elucidated the intricate interplay involving FTO-mediated m6A modification, its consequential downstream effect on PELI3, and the concurrent involvement of autophagy in fostering the emergence of gefitinib resistance within the therapeutic context of NSCLC.

Epigenetics-targeted drugs: current paradigms and future challenges

Epigenetics governs a chromatin state regulatory system through five key mechanisms: DNA modification, histone modification, RNA modification, chromatin remodeling, and non-coding RNA regulation. These mechanisms and their associated enzymes convey genetic information independently of DNA base sequences, playing essential roles in organismal development and homeostasis. Conversely, disruptions in epigenetic landscapes critically influence the pathogenesis of various human diseases. This understanding has laid a robust theoretical groundwork for developing drugs that target epigenetics-modifying enzymes in pathological conditions. Over the past two decades, a growing array of small molecule drugs targeting epigenetic enzymes such as DNA methyltransferase, histone deacetylase, isocitrate dehydrogenase, and enhancer of zeste homolog 2, have been thoroughly investigated and implemented as therapeutic options, particularly in oncology. Additionally, numerous epigenetics-targeted drugs are undergoing clinical trials, offering promising prospects for clinical benefits. This review delineates the roles of epigenetics in physiological and pathological contexts and underscores pioneering studies on the discovery and clinical implementation of epigenetics-targeted drugs. These include inhibitors, agonists, degraders, and multitarget agents, aiming to identify practical challenges and promising avenues for future research. Ultimately, this review aims to deepen the understanding of epigenetics-oriented therapeutic strategies and their further application in clinical settings.

Current insights on m6A RNA modification in acute leukemia: therapeutic targets and future prospects

RNA modification is the critical mechanism for regulating post-transcriptional processes. There are more than 150 RNA modifications reported so far, among which N6-Methyladenosine is the most prevalent one. M6A RNA modification complex consists of 'writers', 'readers' and 'erasers' which together in a group catalyze, recognize and regulate the methylation process of RNA and thereby regulate the stability and translation of mRNA. The discovery of erasers also known as demethylases, revolutionized the research on RNA modifications as it revealed that this modification is reversible. Since then, various studies have focused on discovering the role of m6A modification in various diseases especially cancers. Aberrant expression of these 'readers', 'writers', and 'erasers' is found to be altered in various cancers resulting in disturbance of cellular homeostasis. Acute leukemias are the most common cancer found in pediatric patients and account for 20% of adult cases. Dysregulation of the RNA modifying complex have been reported in development and progression of hematopoietic malignancies. Further, targeting m6A modification is the new approach for cancer immunotherapy and is being explored extensively. This review provides detailed information about current information on the role of m6A RNA modification in acute leukemia and their therapeutic potential.

RNA modifications in long non-coding RNAs and their implications in cancer biology

Long non-coding RNAs (lncRNAs) represent the most diverse class of RNAs in cells and play crucial roles in maintaining cellular functions. RNA modifications, being a significant factor in regulating RNA biology, have been found to be extensively present in lncRNAs and exert regulatory effects on their behavior and biological functions. Most common types of RNA modifications in lncRNAs include N6-methyladenosine (m6A), 5-methylcytosine (m5C), and N1-methyladenosine (m1A). In this review, we summarize the major RNA modification types associated with lncRNAs, the regulatory roles of each modification, and the implications of modified lncRNAs in tumorigenesis and development. By examining these aspects, we aim to provide insights into the role of RNA modifications in lncRNAs and their potential impact on cancer biology.

FTO in oral diseases: Functions, mechanisms, and therapeutic potential

Fat mass and obesity-associated protein (FTO) is the first identified N6-methyladenosine (m6A) demethylase widely distributed in various tissues in adults and children. It plays an essential role in diverse mRNA-associated processes including transcriptional stability, selective splicing, mRNA translocation, and also protein translation. Recently, emerging studies have shown that FTO is involved in the genesis and development of oral diseases. However, the correlation between FTO and oral diseases and its specific regulatory mechanism still needs further study. In this review, we will summarize the discovery, distribution, gene expression, protein structure, biological functions, inhibitors, and quantifying methods of FTO, as well as its regulatory role and mechanism in oral diseases. Notably, FTO genetic variants are strongly associated with periodontal diseases (PDs), temporomandibular joint osteoarthritis (TMJOA), and obstructive sleep apnea (OSA). Besides, the latest studies that describe the relationship between FTO and PDs, head and neck squamous cell carcinoma (HNSCCs), TMJOA, and OSA will be discussed. We elaborate on the regulatory roles of FTO in PDs, HNSCCs, and TMJOA, which are modulated through cell proliferation, cell migration, apoptosis, bone metabolism, and immune response. The review will enrich our understanding of RNA epigenetic modifications in oral diseases and present a solid theoretical foundation for FTO to serve as a novel diagnosis and prognostic biomarker for oral diseases.

Regulation of renal ischemia-reperfusion injury and tubular epithelial cell ferroptosis by pparγ m6a methylation: mechanisms and therapeutic implications

This study aimed to elucidate the role and underlying mechanisms of Peroxisome proliferator-activated receptor gamma (PPARγ) and its m6A methylation in renal ischemia-reperfusion (I/R) injury and ferroptosis of tubular epithelial cells (TECs). High-throughput transcriptome sequencing was performed on renal tissue samples from I/R injury models and sham-operated mice, complemented by in vivo and in vitro experiments focusing on the PPARγ activator Rosiglitazone and the manipulation of METTL14 and IGF2BP2 expression. Key evaluations included renal injury assessment, ferroptosis indicator measurement, and m6A methylation analysis of PPARγ. Our findings highlight the critical role of the PPARγ pathway and ferroptosis in renal I/R injury, with Rosiglitazone ameliorating renal damage and TEC ferroptosis. METTL14-mediated m6A methylation of PPARγ, dependent on IGF2BP2, emerged as a pivotal regulator of PPARγ expression, renal injury, and ferroptosis. This study reveals that PPARγ m6A methylation, orchestrated by METTL14 through an IGF2BP2-dependent mechanism, plays a crucial role in mitigating renal I/R injury and TEC ferroptosis. These insights offer promising avenues for therapeutic strategies targeting acute kidney injury.

Decoding the epitranscriptome: a new frontier for cancer therapy and drug resistance

As the role of RNA modification in gene expression regulation and human diseases, the "epitranscriptome" has been shown to be an important player in regulating many physiological and pathological processes. Meanwhile, the phenomenon of cancer drug resistance is becoming more and more frequent, especially in the case of cancer chemotherapy resistance. In recent years, research on relationship between post-transcriptional modification and cancer including drug resistance has become a hot topic, especially the methylation of the sixth nitrogen site of RNA adenosine-m6A (N6-methyladenosine). m6A modification is the most common post-transcriptional modification of eukaryotic mRNA, accounting for 80% of RNA methylation modifications. At the same time, several other modifications of RNA, such as N1-methyladenosine (m1A), 5-methylcytosine (m5C), 3-methylcytosine (m3C), pseudouridine (Ψ) and N7-methylguanosine (m7G) have also been demonstrated to be involved in cancer and drug resistance. This review mainly discusses the research progress of RNA modifications in the field of cancer and drug resistance and targeting of m6A regulators by small molecule modulators, providing reference for future study and development of combination therapy to reverse cancer drug resistance.

RNA modifications in the progression of liver diseases: from fatty liver to cancer

Non-alcoholic fatty liver disease (NAFLD) has emerged as a prominent global health concern associated with high risk of metabolic syndrome, and has impacted a substantial segment of the population. The disease spectrum ranges from simple fatty liver to non-alcoholic steatohepatitis (NASH), which can progress to cirrhosis and hepatocellular carcinoma (HCC) and is increasingly becoming a prevalent indication for liver transplantation. The existing therapeutic options for NAFLD, NASH, and HCC are limited, underscoring the urgent need for innovative treatment strategies. Insights into gene expression, particularly RNA modifications such as N6 methyladenosine (m6A), hold promising avenues for interventions. These modifications play integral roles in RNA metabolism and cellular functions, encompassing the entire NAFLD-NASH-HCC progression. This review will encompass recent insights on diverse RNA modifications, including m6A, pseudouridine (ψ), N1-methyladenosine (m1A), and 5-methylcytidine (m5C) across various RNA species. It will uncover their significance in crucial aspects such as steatosis, inflammation, fibrosis, and tumorigenesis. Furthermore, prospective research directions and therapeutic implications will be explored, advancing our comprehensive understanding of the intricate interconnected nature of these pathological conditions.

Upregulation of LY6K induced by FTO-mediated demethylation promotes the tumorigenesis and metastasis of oral squamous cell carcinoma via CAV-1-mediated ERK1/2 signaling activation

Lymphocyte antigen 6 complex locus K (LY6K) has been demonstrated to play a significant role in cancers and identified as a therapeutic biomarker for head and neck squamous cell carcinoma. However, the role of LY6K in oral squamous cell carcinoma (OSCC) has not been explored. The current study discovered that LY6K was aberrantly upregulated in OSCC cell lines and tissues and that high LY6K expression significantly correlated with poorer survival of OSCC patients. Through stable knockdown of LY6K, we found that the growth, colony formation, migration, and invasion of OSCC cells were substantially suppressed. In addition, tumor growth and lung metastasis in vivo were effectively inhibited by LY6K depletion. Mechanically, LY6K binds with CAV-1 and activates CAV-1-mediated MAPK/ERK signaling to exert its oncogenic effects on OSCC. In addition, LY6K expression in OSCC was discovered to be regulated by FTO-mediated RNA N6-methyladenosine (m6A) modification in an IGF2BP1-dependent manner. Generally, LY6K expression was upregulated by FTO-mediated demethylation in OSCC, which promoted the tumorigenesis and metastasis of OSCC via activating the CAV-1-mediated ERK1/2 signaling pathway.

RNA m6A modification in ferroptosis: implications for advancing tumor immunotherapy

The pursuit of innovative therapeutic strategies in oncology remains imperative, given the persistent global impact of cancer as a leading cause of mortality. Immunotherapy is regarded as one of the most promising techniques for systemic cancer therapies among the several therapeutic options available. Nevertheless, limited immune response rates and immune resistance urge us on an augmentation for therapeutic efficacy rather than sticking to conventional approaches. Ferroptosis, a novel reprogrammed cell death, is tightly correlated with the tumor immune environment and interferes with cancer progression. Highly mutant or metastasis-prone tumor cells are more susceptible to iron-dependent nonapoptotic cell death. Consequently, ferroptosis-induction therapies hold the promise of overcoming resistance to conventional treatments. The most prevalent post-transcriptional modification, RNA m6A modification, regulates the metabolic processes of targeted RNAs and is involved in numerous physiological and pathological processes. Aberrant m6A modification influences cell susceptibility to ferroptosis, as well as the expression of immune checkpoints. Clarifying the regulation of m6A modification on ferroptosis and its significance in tumor cell response will provide a distinct method for finding potential targets to enhance the effectiveness of immunotherapy. In this review, we comprehensively summarized regulatory characteristics of RNA m6A modification on ferroptosis and discussed the role of RNA m6A-mediated ferroptosis on immunotherapy, aiming to enhance the effectiveness of ferroptosis-sensitive immunotherapy as a treatment for immune-resistant malignancies.

Methylation modifications in tRNA and associated disorders: Current research and potential therapeutic targets

High-throughput sequencing has sparked increased research interest in RNA modifications, particularly tRNA methylation, and its connection to various diseases. However, the precise mechanisms underpinning the development of these diseases remain largely elusive. This review sheds light on the roles of several tRNA methylations (m1A, m3C, m5C, m1G, m2G, m7G, m5U, and Nm) in diverse biological functions, including metabolic processing, stability, protein interactions, and mitochondrial activities. It further outlines diseases linked to aberrant tRNA modifications, related enzymes, and potential underlying mechanisms. Moreover, disruptions in tRNA regulation and abnormalities in tRNA-derived small RNAs (tsRNAs) contribute to disease pathogenesis, highlighting their potential as biomarkers for disease diagnosis. The review also delves into the exploration of drugs development targeting tRNA methylation enzymes, emphasizing the therapeutic prospects of modulating these processes. Continued research is imperative for a comprehensive comprehension and integration of these molecular mechanisms in disease diagnosis and treatment.

Writers, readers, and erasers RNA modifications and drug resistance in cancer

Drug resistance in cancer cells significantly diminishes treatment efficacy, leading to recurrence and metastasis. A critical factor contributing to this resistance is the epigenetic alteration of gene expression via RNA modifications, such as N6-methyladenosine (m6A), N1-methyladenosine (m1A), 5-methylcytosine (m5C), 7-methylguanosine (m7G), pseudouridine (Ψ), and adenosine-to-inosine (A-to-I) editing. These modifications are pivotal in regulating RNA splicing, translation, transport, degradation, and stability. Governed by "writers," "readers," and "erasers," RNA modifications impact numerous biological processes and cancer progression, including cell proliferation, stemness, autophagy, invasion, and apoptosis. Aberrant RNA modifications can lead to drug resistance and adverse outcomes in various cancers. Thus, targeting RNA modification regulators offers a promising strategy for overcoming drug resistance and enhancing treatment efficacy. This review consolidates recent research on the role of prevalent RNA modifications in cancer drug resistance, with a focus on m6A, m1A, m5C, m7G, Ψ, and A-to-I editing. Additionally, it examines the regulatory mechanisms of RNA modifications linked to drug resistance in cancer and underscores the existing limitations in this field.

Medicinal chemistry aspects of fat mass and obesity associated protein: structure, function and inhibitors

Adiposity and obesity-related proteins (FTO), the earliest identified mRNA N6-methyladenosine (m6A) demethylases, are known to play crucial roles in several biological processes. Therefore, FTO is a promising target for anticancer treatment. Understanding the biological functions and regulatory mechanisms of FTO targets can serve as guidelines for drug development. Despite significant efforts to develop FTO inhibitors, no specific small-molecule inhibitors have entered clinical trials so far. In this manuscript, we review the relationship between FTO and various cancers, the small-molecule inhibitors developed against FTO targets from the perspective of medicinal chemistry and other fields, and describe their structural optimization process and structure-activity relationship, providing clues for their future development direction.

Small molecules that regulate the N6-methyladenosine RNA modification as potential anti-cancer agents

Epitranscriptomics, the field of post-translational RNA modifications, is a burgeoning domain of research that has recently received significant attention for its role in multiple diseases, including cancer. N6-methyladenosine (m6A) is the most prominent post-translational RNA modification and plays a critical role in RNA transcription, processing, translation, and metabolism. The m6A modification is controlled by three protein classes known as writers (methyltransferases), erasers (demethylases), and readers (m6A-binding proteins). Each class of m6A regulatory proteins has been implicated in cancer initiation and progression. As such, many of these proteins have been identified as potential targets for anti-cancer chemotherapeutics. In this work, we provide an overview of the role m6A-regulating proteins play in cancer and discuss the current state of small molecule therapeutics targeting these proteins.

Clinical Perspectives in Epitranscriptomics

Epitranscriptomics, the study of reversible and dynamic chemical marks on the RNA, is rapidly emerging as a pivotal field in post-transcriptional gene expression regulation. Increasing knowledge about epitranscriptomic landscapes implicated in disease pathogenesis proves an invaluable opportunity for the identification of epitranscriptomic biomarkers and the development of new potential therapeutic drugs. Hence, recent advances in the characterization of these marks and associated enzymes in both health and disease blaze a trail toward the use of epitranscriptomics approaches for clinical applications. Here, we review the latest studies to provide a wide and comprehensive perspective of clinical epitranscriptomics and emphasize its transformative potential in shaping future health care paradigms.

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.

Protective effect of vitexin against high fat-induced vascular endothelial inflammation through inhibiting trimethylamine N-oxide-mediated RNA m6A modification

A high-fat diet (HFD) is a major risk factor for cardiovascular disease. However, the specific effects of a HFD on vascular inflammation and the protective role of vitexin, a bioactive compound derived from food, require further research. This study investigated the protective effects of vitexin intervention against HFD-induced vascular inflammation and its underlying mechanism. The results demonstrated that vitexin intervention significantly reduced body weight, serum total cholesterol, and low-density lipoprotein cholesterol levels in HFD-fed mice. Vitexin also improved vascular pathological changes and the inflammatory status in the mice. Furthermore, vitexin intervention reduced serum TMAO levels in HFD-fed mice by altering the gut microbiota composition. The HFD significantly increased N6-methyladenosine (m6A) levels in aorta tissues, while vitexin intervention reversed this abnormal m6A level. Through metabolite affinity responsive target fluorescence quenching and molecular docking assays, it was found that vitexin could directly bind to fat mass and obesity-associated protein (FTO), potentially promoting m6A demethylation. The dose-response relationship between TMAO and inflammation/m6A was further validated in HUVEC cells and in vivo mouse experiments. Specifically, TMAO increased m6A levels and inflammation, while vitexin inhibited TMAO-mediated m6A modification, exhibiting anti-inflammatory effects. In conclusion, this study demonstrates the protective role of vitexin against HFD-induced vascular inflammation by inhibiting TMAO-mediated RNA m6A modification, laying the foundation for the development of functional foods.

The role of RNA methylation in tumor immunity and its potential in immunotherapy

RNA methylation, a prevalent post-transcriptional modification, has garnered considerable attention in research circles. It exerts regulatory control over diverse biological functions by modulating RNA splicing, translation, transport, and stability. Notably, studies have illuminated the substantial impact of RNA methylation on tumor immunity. The primary types of RNA methylation encompass N6-methyladenosine (m6A), 5-methylcytosine (m5C), N1-methyladenosine (m1A), and N7-methylguanosine (m7G), and 3-methylcytidine (m3C). Compelling evidence underscores the involvement of RNA methylation in regulating the tumor microenvironment (TME). By affecting RNA translation and stability through the "writers", "erasers" and "readers", RNA methylation exerts influence over the dysregulation of immune cells and immune factors. Consequently, RNA methylation plays a pivotal role in modulating tumor immunity and mediating various biological behaviors, encompassing proliferation, invasion, metastasis, etc. In this review, we discussed the mechanisms and functions of several RNA methylations, providing a comprehensive overview of their biological roles and underlying mechanisms within the tumor microenvironment and among immunocytes. By exploring how these RNA modifications mediate tumor immune evasion, we also examine their potential applications in immunotherapy. This review aims to provide novel insights and strategies for identifying novel targets in RNA methylation and advancing cancer immunotherapy efficacy.

Role of m6A modifications in immune evasion and immunotherapy

RNA modification has garnered increasing attention in recent years due to its pivotal role in tumorigenesis and immune surveillance. N6-methyladenosine (m6A) modification is the most prevalent RNA modification, which can affect the expression of RNA by methylating adenylate at the sixth N position to regulate the occurrence and development of tumors. Dysregulation of m6A affects the activation of cancer-promoting pathways, destroys immune cell function, maintains immunosuppressive microenvironment, and promotes tumor cell growth. In this review, we delve into the latest insights into how abnormalities in m6A modification in both tumor and immune cells orchestrate immune evasion through the activation of signaling pathways. Furthermore, we explore how dysregulated m6A modification in tumor cells influences immune cells, thereby regulating tumor immune evasion via interactions within the tumor microenvironment (TME). Lastly, we highlight recent discoveries regarding specific inhibitors of m6A modulators and the encapsulation of m6A-targeting nanomaterials for cancer therapy, discussing their potential applications in immunotherapy.

Small molecule inhibitors targeting m6A regulators

As the most common form of epigenetic regulation by RNA, N6 methyladenosine (m6A) modification is closely involved in physiological processes, such as growth and development, stem cell renewal and differentiation, and DNA damage response. Meanwhile, its aberrant expression in cancer tissues promotes the development of malignant tumors, as well as plays important roles in proliferation, metastasis, drug resistance, immunity and prognosis. This close association between m6A and cancers has garnered substantial attention in recent years. An increasing number of small molecules have emerged as potential agents to target m6A regulators for cancer treatment. These molecules target the epigenetic level, enabling precise intervention in RNA modifications and efficiently disrupting the survival mechanisms of tumor cells, thus paving the way for novel approaches in cancer treatment. However, there is currently a lack of a comprehensive review on small molecules targeting m6A regulators for anti-tumor. Here, we have comprehensively summarized the classification and functions of m6A regulators, elucidating their interactions with the proliferation, metastasis, drug resistance, and immune responses in common cancers. Furthermore, we have provided a comprehensive overview on the development, mode of action, pharmacology and structure-activity relationships of small molecules targeting m6A regulators. Our aim is to offer insights for subsequent drug design and optimization, while also providing an outlook on future prospects for small molecule development targeting m6A.

RNA methylation-related inhibitors: Biological basis and therapeutic potential for cancer therapy

RNA methylation is widespread in nature. Abnormal expression of proteins associated with RNA methylation is strongly associated with a number of human diseases including cancer. Increasing evidence suggests that targeting RNA methylation holds promise for cancer treatment. This review specifically describes several common RNA modifications, such as the relatively well-studied N6-methyladenosine, as well as 5-methylcytosine and pseudouridine (Ψ). The regulatory factors involved in these modifications and their roles in RNA are also comprehensively discussed. We summarise the diverse regulatory functions of these modifications across different types of RNAs. Furthermore, we elucidate the structural characteristics of these modifications along with the development of specific inhibitors targeting them. Additionally, recent advancements in small molecule inhibitors targeting RNA modifications are presented to underscore their immense potential and clinical significance in enhancing therapeutic efficacy against cancer. KEY POINTS: In this paper, several important types of RNA modifications and their related regulatory factors are systematically summarised. Several regulatory factors related to RNA modification types were associated with cancer progression, and their relationships with cancer cell migration, invasion, drug resistance and immune environment were summarised. In this paper, the inhibitors targeting different regulators that have been proposed in recent studies are summarised in detail, which is of great significance for the development of RNA modification regulators and cancer treatment in the future.

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.

Oxidative stress-mediated activation of FTO exacerbates impairment of the epithelial barrier by up-regulating IKBKB via N6-methyladenosine-dependent mRNA stability in asthmatic mice exposed to PM2.5

In order to comprehend the underlying mechanisms contributing to the development and exacerbation of asthma resulting from exposure to fine particulate matter (PM2.5), we established an asthmatic model in fat mass and obesity-associated gene knockdown mice subjected to PM2.5 exposure. Histological analyses using hematoxylin-eosin (HE) and Periodic Acid-Schiff (PAS) staining revealed that the down-regulation of the fat mass and obesity-associated gene (Fto) expression significantly ameliorated the pathophysiological alterations observed in asthmatic mice exposed to PM2.5. Furthermore, the down-regulation of Fto gene expression effectively attenuated damage to the airway epithelial barrier. Additionally, employing in vivo and in vitro models, we elucidated that PM2.5 modulated FTO expression by inducing oxidative stress. Asthmatic mice exposed to PM2.5 exhibited elevated Fto expression, which correlated with increased levels of reactive oxygen species. Similarly, when cells were exposed to PM2.5, FTO expression was up-regulated in a ROS-dependent manner. Notably, the administration of N-acetyl cysteine successfully reversed the PM2.5-induced elevation in FTO expression. Concurrently, we performed transcriptome-wide Methylated RNA immunoprecipitation Sequencing (MeRIP-seq) analysis subsequent to PM2.5 exposure. Through the implementation of Gene Set Enrichment Analysis and m6A-IP-qPCR, we successfully identified inhibitor of nuclear factor kappa B kinase subunit beta (IKBKB) as a target gene regulated by FTO. Interestingly, exposure to PM2.5 led to increased expression of IKBKB, while m6A modification on IKBKB mRNA was reduced. Furthermore, our investigation revealed that PM2.5 also regulated IKBKB through oxidative stress. Significantly, the down-regulation of IKBKB effectively mitigated epithelial barrier damage in cells exposed to PM2.5 by modulating nuclear factor-kappa B (NF-κB) signaling. Importantly, we discovered that decreased m6A modification on IKBKB mRNA facilitated by FTO enhanced its stability, consequently resulting in up-regulation of IKBKB expression. Collectively, our findings propose a novel role for FTO in the regulation of IKBKB through m6A-dependent mRNA stability in the context of PM2.5-induced oxidative stress. Therefore, it is conceivable that the utilization of antioxidants or inhibition of FTO could represent potential therapeutic strategies for the management of asthma exacerbated by PM2.5 exposure.

M6A RNA methylation in biliary tract cancer: the function roles and potential therapeutic implications

Biliary tract cancers (BTCs) are relatively rare malignancies with a poor prognosis. For advanced BTCs, the efficacy of current chemotherapeutic approaches is limited. Consequently, there is an urgent need to deepen our understanding of the molecular mechanisms underlying BTC tumorigenesis and development for the exploration of effective targeted therapies. N6-methyladenosine (m6A), the most abundant RNA modifications in eukaryotes, is found usually dysregulated and involved in tumorigenesis, progression, and drug resistance in tumors. Numerous studies have confirmed that aberrant m6A regulators function as either oncogenes or tumor suppressors in BTCs by the reversible regulation of RNA metabolism, including splicing, export, degradation and translation. In this review, we summarized the current roles of the m6A regulators and their functional impacts on RNA fate in BTCs. The improved understanding of m6A modification in BTCs also provides a reasonable outlook for the exploration of new diagnostic strategies and efficient therapeutic targets.

Update on N6-methyladenosine methylation in obesity-related diseases

Obesity is a chronic metabolic disease that is closely related to type 2 diabetes mellitus, cardiovascular diseases, nonalcoholic fatty liver disease, obstructive sleep apnea, and osteoarthritis. The prevalence of obesity is increasing rapidly every year and is recognized as a global public health problem. In recent years, the role of epigenetics in the development of obesity and related diseases has been recognized and is currently a research hotspot. N6-methyladenosine (m6A) methylation is the most abundant epigenetic modification in the eukaryotic RNA, including mRNA and noncoding RNA. Several studies have shown that the m6A modifications in the target mRNA and the corresponding m6A regulators play a significant role in lipid metabolism and are strongly associated with the pathogenesis of obesity-related diseases. In this review, the latest research findings regarding the role of m6A methylation in obesity and related metabolic diseases are summarized. The authors' aim is to highlight evidence that suggests the clinical utility of m6A modifications and the m6A regulators as novel early prediction biomarkers and precision therapeutics for obesity and obesity-related diseases.

Discovery of Pyrazolo[1,5-a]pyrimidine Derivative as a Novel and Selective ALKBH5 Inhibitor for the Treatment of AML

M6A (N6-methyladenosine) plays a significant role in regulating RNA processing, splicing, nucleation, translation, and stability. AlkB homologue 5 (ALKBH5) is an Fe(II)/2-oxoglutarate (2-OG)-dependent dioxygenase that demethylates mono- or dimethylated adenosines. ALKBH5 can be regarded as an oncogenic factor for various human cancers. However, the discovery of potent and selective ALKBH5 inhibitors remains a challenge. We identified DDO-2728 as a novel and selective inhibitor of ALKBH5 by structure-based virtual screening and optimization. DDO-2728 was not a 2-oxoglutarate analogue and could selectively inhibit the demethylase activity of ALKBH5 over FTO. DDO-2728 increased the abundance of m6A modifications in AML cells, reduced the mRNA stability of TACC3, and inhibited cell cycle progression. Furthermore, DDO-2728 significantly suppressed tumor growth in the MV4-11 xenograft mouse model and showed a favorable safety profile. Collectively, our results highlight the development of a selective probe for ALKBH5 that will pave the way for the further study of ALKBH5 targeting therapies.

N6-methyladenosine (m6A) methylation in kidney diseases: Mechanisms and therapeutic potential

The N6-methyladenosine (m6A) modification is regulated by methylases, commonly referred to as "writers," and demethylases, known as "erasers," leading to a dynamic and reversible process. Changes in m6A levels have been implicated in a wide range of cellular processes, including nuclear RNA export, mRNA metabolism, protein translation, and RNA splicing, establishing a strong correlation with various diseases. Both physiologically and pathologically, m6A methylation plays a critical role in the initiation and progression of kidney disease. The methylation of m6A may also facilitate the early diagnosis and treatment of kidney diseases, according to accumulating research. This review aims to provide a comprehensive overview of the potential role and mechanism of m6A methylation in kidney diseases, as well as its potential application in the treatment of such diseases. There will be a thorough examination of m6A methylation mechanisms, paying particular attention to the interplay between m6A writers, m6A erasers, and m6A readers. Furthermore, this paper will elucidate the interplay between various kidney diseases and m6A methylation, summarize the expression patterns of m6A in pathological kidney tissues, and discuss the potential therapeutic benefits of targeting m6A in the context of kidney diseases.

The role of N6-methyladenosine methylation in PAHs-induced cancers

Polycyclic aromatic hydrocarbons (PAHs), which are a wide range of environmental toxicants, may act on humans through inhalation, ingestion, and skin contact, resulting in a range of toxic reactions. Epidemiological studies showed that long-term exposure to PAHs in the occupational and living environment results in a substantial rise in the incidence rate of many cancers in the population, so the prevention and treatment of these diseases have become a major worldwide public health problem. N6-methyladenosine (m6A) modification greatly affects the metabolism of RNA and is implicated in the etiopathogenesis of many kinds of diseases. In addition, m6A-binding proteins have an important role in disease development. The abnormal expression of these can cause the malignant proliferation, migration, invasion, and metastasis of cancers. Furthermore, a growing number of studies revealed that environmental toxicants are one of the cancer risk factors and are related to m6A modifications. Exposure to environmental toxicants can alter the methylation level of m6A and the expression of the m6A-binding protein, thus promoting the occurrence and development of cancers through diverse mechanisms. m6A may serve as a biomarker for early environmental exposure. Through the study of m6A, we can find the health injury early, thus providing a new sight for preventing and curing environmental health-related diseases.

m6 A mRNA methylation: Biological features, mechanisms, and therapeutic potentials in type 2 diabetes mellitus

As the most common internal post-transcriptional RNA modification in eukaryotic cells, N6-methyladenosine (m6 A) performs a dynamic and reversible role in a variety of biological processes mediated by methyltransferases (writers), demethylases (erasers), and m6 A binding proteins (readers). M6 A methylation enables transcriptome conversion in different signals that regulate various physiological activities and organ development. Over the past few years, emerging studies have identified that mRNA m6 A regulators defect in β-cell leads to abnormal regulation of the target mRNAs, thereby resulting in β-cell dysfunction and loss of β-cell identity and mass, which are strongly associated with type 2 diabetes mellitus (T2DM) pathogenesis. Also, mRNA m6 A modification has been implicated with insulin resistance in muscles, fat, and liver cells/tissues. In this review, we elaborate on the biological features of m6 A methylation; provide a comprehensive overview of the underlying mechanisms that how it controls β-cell function, identity, and mass as well as insulin resistance; highlight its connections to glucose metabolism and lipid metabolism linking to T2DM; and further discuss its role in diabetes complications and its therapeutic potentials for T2DM diagnosis and treatment.

The role of m6A demethylases in lung cancer: diagnostic and therapeutic implications

m6A is the most prevalent internal modification of eukaryotic mRNA, and plays a crucial role in tumorigenesis and various other biological processes. Lung cancer is a common primary malignant tumor of the lungs, which involves multiple factors in its occurrence and progression. Currently, only the demethylases FTO and ALKBH5 have been identified as associated with m6A modification. These demethylases play a crucial role in regulating the growth and invasion of lung cancer cells by removing methyl groups, thereby influencing stability and translation efficiency of mRNA. Furthermore, they participate in essential biological signaling pathways, making them potential targets for intervention in lung cancer treatment. Here we provides an overview of the involvement of m6A demethylase in lung cancer, as well as their potential application in the diagnosis, prognosis and treatment of the disease.

N6-methyladenosine (m6A) in cancer therapeutic resistance: Potential mechanisms and clinical implications

Cancer therapy resistance (CTR) is the development of cancer resistance to multiple therapeutic strategies, which severely affects clinical response and leads to cancer progression, recurrence, and metastasis. N6-methyladenosine (m6A) has been identified as the most common, abundant, and conserved internal transcriptional alterations of RNA modifications, regulating RNA splicing, translation, stabilization, degradation, and gene expression, and is involved in the development and progression of a variety of diseases, including cancer. Recent studies have shown that m6A modifications play a critical role in both cancer development and progression, especially in reversing CTR. Although m6A modifications have great potential in CTR, the specific molecular mechanisms are not fully elucidated. In this review, we summarize the potential molecular mechanisms of m6A modification in CTR. In addition, we update recent advances in natural products from Traditional Chinese Medicines (TCM) and small-molecule lead compounds targeting m6A modifications, and discuss the great potential and clinical implications of these inhibitors targeting m6A regulators and combinations with other therapies to improve clinical efficacy and overcome CTR.

RNA methylation, homologous recombination repair and therapeutic resistance

Homologous recombination (HR) repair of DNA double-strand breaks (DSBs) is critical for maintaining genomic integrity and stability. Defects in HR increase the risk of tumorigenesis. However, many human tumors exhibit enhanced HR repair capabilities, consequently endowing tumor cells with resistance to DNA-damaging chemotherapy and radiotherapy. This review summarizes the role of RNA methylation in HR repair and therapeutic resistance in human tumors. We also analyzed the interactions between RNA methylation and other HR-modulating modifications including histone acetylation, histone deacetylation, ubiquitination, deubiquitination, protein arginine methylation, and gene transcription. This review proposes that targeting RNA methylation is a promising approach to overcoming HR-mediated therapeutic resistance.

The role of N6-methyladenosine (m6A) in kidney diseases

Chemical modifications are a specific and efficient way to regulate the function of biological macromolecules. Among them, RNA molecules exhibit a variety of modifications that play important regulatory roles in various biological processes. More than 170 modifications have been identified in RNA molecules, among which the most common internal modifications include N6-methyladenine (m6A), n1-methyladenosine (m1A), 5-methylcytosine (m5C), and 7-methylguanine nucleotide (m7G). The most widely affected RNA modification is m6A, whose writers, readers, and erasers all have regulatory effects on RNA localization, splicing, translation, and degradation. These functions, in turn, affect RNA functionality and disease development. RNA modifications, especially m6A, play a unique role in renal cell carcinoma disease. In this manuscript, we will focus on the biological roles of m6A in renal diseases such as acute kidney injury, chronic kidney disease, lupus nephritis, diabetic kidney disease, and renal cancer.

RNA modification: mechanisms and therapeutic targets

RNA modifications are dynamic and reversible chemical modifications on substrate RNA that are regulated by specific modifying enzymes. They play important roles in the regulation of many biological processes in various diseases, such as the development of cancer and other diseases. With the help of advanced sequencing technologies, the role of RNA modifications has caught increasing attention in human diseases in scientific research. In this review, we briefly summarized the basic mechanisms of several common RNA modifications, including m6A, m5C, m1A, m7G, Ψ, A-to-I editing and ac4C. Importantly, we discussed their potential functions in human diseases, including cancer, neurological disorders, cardiovascular diseases, metabolic diseases, genetic and developmental diseases, as well as immune disorders. Through the "writing-erasing-reading" mechanisms, RNA modifications regulate the stability, translation, and localization of pivotal disease-related mRNAs to manipulate disease development. Moreover, we also highlighted in this review all currently available RNA-modifier-targeting small molecular inhibitors or activators, most of which are designed against m6A-related enzymes, such as METTL3, FTO and ALKBH5. This review provides clues for potential clinical therapy as well as future study directions in the RNA modification field. More in-depth studies on RNA modifications, their roles in human diseases and further development of their inhibitors or activators are needed for a thorough understanding of epitranscriptomics as well as diagnosis, treatment, and prognosis of human diseases.

Rational Design of RNA Demethylase FTO Inhibitors with Enhanced Antileukemia Drug-Like Properties

The fat mass and obesity-associated protein (FTO) is an RNA N⁶-methyladenosine (m⁶A) demethylase highly expressed in diverse cancers including acute myeloid leukemia (AML). To improve antileukemia drug-like properties, we have designed 44/ZLD115, a flexible alkaline side-chain-substituted benzoic acid FTO inhibitor derived from FB23. A combination of structure-activity relationship analysis and lipophilic efficiency-guided optimization demonstrates that 44/ZLD115 exhibits better drug-likeness than the previously reported FTO inhibitors, FB23 and 13a/Dac85. Then, 44/ZLD115 shows significant antiproliferative activity in leukemic NB4 and MOLM13 cell lines. Moreover, 44/ZLD115 treatment noticeably increases m⁶A abundance on the AML cell RNA, upregulates RARA gene expression, and downregulates MYC gene expression in MOLM13 cells, which are consistent with FTO gene knockdown. Lastly, 44/ZLD115 exhibits antileukemic activity in xenograft mice without substantial side effects. This FTO inhibitor demonstrates promising properties that can be further developed for antileukemia applications.

The Functional Role and Regulatory Mechanism of FTO m6A RNA Demethylase in Human Uterine Leiomyosarcoma

Uterine leiomyosarcoma (uLMS) is the most frequent subtype of uterine sarcoma that presents a poor prognosis and high rates of recurrence and metastasis. The origin and molecular mechanism underlying and driving its clinical and biological behavior remain largely unknown. Recently, we and others have revealed the role of microRNAs, DNA methylation, and histone modifications in contributing to the pathogenesis of uLMS. However, the connection between reversible m6A RNA methylation and uLMS pathogenesis remains unclear. In this study, we assessed the role and mechanism of FTO m6A RNA demethylase in the pathogenesis of uLMS. Immunohistochemistry analysis revealed that the levels of RNA demethylases FTO and ALKBH5 were aberrantly upregulated in uLMS tissues compared to adjacent myometrium with a significant change by histochemical scoring assessment (p < 0.01). Furthermore, the inhibition of FTO demethylase with its small, potent inhibitor (Dac51) significantly decreased the uLMS proliferation dose-dependently via cell cycle arrest. Notably, RNA-seq analysis revealed that the inhibition of FTO with Dac51 exhibited a significant decrease in cell-cycle-related genes, including several CDK members, and a significant increase in the expression of CDKN1A, which correlated with a Dac51-exerted inhibitory effect on cell proliferation. Moreover, Dac51 treatment allowed the rewiring of several critical pathways, including TNFα signaling, KRAS signaling, inflammation response, G2M checkpoint, and C-Myc signaling, among others, leading to the suppression of the uLMS phenotype. Moreover, transcription factor (TF) analyses suggested that epitranscriptional alterations by Dac51 may alter the cell cycle-related gene expression via TF-driven pathways and epigenetic networks in uLMS cells. This intersection of RNA methylation and other epigenetic controls and pathways provides a framework to better understand uterine diseases, particularly uLMS pathogenesis with a dysregulation of RNA methylation machinery. Therefore, targeting the vulnerable epitranscriptome may provide an additional regulatory layer for a promising and novel strategy for treating patients with this aggressive uterine cancer.

The diverse role of RNA methylation in esophageal cancer

Esophageal cancer is one of the major life-threatening diseases in the world. RNA methylation is the most common post-transcriptional modification and a wide-ranging regulatory system controlling gene expression. Numerous studies have revealed that dysregulation of RNA methylation is critical for cancer development and progression. However, the diverse role of RNA methylation and its regulators in esophageal cancer remains to be elucidated and summarized. In this review, we focus on the regulation of major RNA methylation, including m ⁶A, m ⁵C, and m ⁷G, as well as the expression patterns and clinical implications of its regulators in esophageal cancer. We systematically summarize how these RNA modifications affect the "life cycle" of target RNAs, including mRNA, microRNA, long non-coding RNA, and tRNA. The downstream signaling pathways associated with RNA methylation during the development and treatment of esophageal cancer are also discussed in detail. Further studies on how these modifications function together in the microenvironment of esophageal cancer will draw a clearer picture of the clinical application of novel and specific therapeutic strategies.