METTL16 epigenetically enhances GPX4 expression via m6A modification to promote breast cancer progression by inhibiting ferroptosis

METTL16/IGF2BP2 axis enhances malignant progression and DDP resistance through up-regulating COL4A1 by mediating the m6A methylation modification of LAMA4 in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is the third most common malignant tumor after gastric cancer and esophageal cancer, which is a serious threat to human health. Methyltransferase-like protein 16 (METTL16) regulates the occurrence and development of various cancers, but its molecular mechanism in HCC has not been fully investigated.

METHODS

A series of databases were used to predict gene expression, methylation sites, correlation analysis, and protein interaction analysis. Gene expression levels were detected by quantitative real-time polymerase chain reaction (qRT-PCR), western blot, and immunohistochemistry (IHC). What's more, drug-resistant cell lines were established for drug resistance analysis. Cell proliferation was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and 5-ethynyl-2'-deoxyuridine (EdU) staining. Flow cytometry, transwell and wound healing assays were used for apoptosis, invasion and migration, respectively. In addition, the regulatory mechanism of METTL16 in HCC was investigated by methylated RNA immunoprecipitation (MeRIP), RNA immunoprecipitation (RIP) and co-immunoprecipitation (Co-IP). Finally, constructing subcutaneous transplanted tumor in nude mice confirmed the effect of METTL16 in vivo.

RESULTS

METTL16 was up-regulated in HCC drug-resistant tissues and cells. Knockdown of METTL16 inhibited Cisplatin (DDP) resistance, proliferation, invasion and migration of HCC cells, but promoted apoptosis. Besides, laminin subunit alpha 4 (LAMA4), which was overexpressed in HCC drug-resistant tissues and cells, was selected as the target of METTL16. Mechanistically, METTL16 and m6A reader insulin like growth factor 2 mRNA binding protein 2 (IGF2BP2) co-regulated the m6A modification and mRNA stability of LAMA4, and LAMA4 weakened the effects of METTL16 knockdown on HCC drug-resistance. Meanwhile, LAMA4 bound to collagen type IV alpha 1 chain (COL4A1) and facilitated DDP resistance and HCC progression via COL4A1. Similarly, in vivo, METTL16 induced tumor growth, as well as LAMA4 and COL4A1 expression, and increased DDP resistance.

CONCLUSION

METTL16 and IGF2BP2 jointly mediated the m6A methylation modification of LAMA4, thereby promoting DDP resistance and malignant progression of HCC through regulation of COL4A1.

Role of METTL16 in PPARγ methylation and osteogenic differentiation

Osteoporosis, a prevalent bone disease, is characterized by the deterioration of bone tissue microstructure and imbalanced osteogenesis. The regulatory role of PPARγ m6A methylation mediated by METTL16 remains poorly elucidated. This study utilized advanced single-cell RNA sequencing (scRNA-seq) and Bulk RNA-seq techniques to explore how METTL16 influences the osteogenic differentiation of Bone Marrow-Derived Mesenchymal Stem Cells (BMSCs) and its implication in osteoporosis. The research revealed that METTL16 enhances the suppression of osteogenic differentiation in BMSCs, while PPARγ is associated with BMSC ferroptosis. Mechanistically, METTL16 facilitates the m6A modification of PPARγ transcription, thereby promoting ferroptosis in BMSCs and impeding their osteogenic differentiation. The in vivo animal experiments confirmed the pivotal role of the METTL16-PPARγ axis in osteoporosis development in mice. These findings suggest that the regulation of PPARγ m6A methylation by METTL16, leading to ferroptosis, is a critical mechanism impacting BMSC osteogenic differentiation and the pathogenesis of osteoporosis.

Summary of the mechanism of ferroptosis regulated by m6A modification in cancer progression

The most common form of internal RNA modification in eukaryotes is called n6-methyladenosine (m6A) methylation. It has become more and more well-known as a research issue in recent years since it alters RNA metabolism and is involved in numerous biological processes. Currently, m6A alteration offers new opportunities in clinical applications and is intimately linked to carcinogenesis. Ferroptosis-a form of iron-dependent, lipid peroxidation-induced regulated cell death-was discovered. In the development of cancer, it has become an important factor. According to newly available data, ferroptosis regulates tumor growth, and cancer exhibits aberrant m6A levels in crucial ferroptosis regulatory components. On the other hand, m6A has multiple roles in the development of tumors, and the relationship between m6A-modified ferroptosis and malignancies is quite intricate. In this review, we first give a thorough review of the regulatory and functional roles of m6A methylation, focusing on the molecular processes of m6A through the regulation of ferroptosis in human cancer progression and metastasis, which are strongly associated to cancer initiation, progression, and drug resistance. Therefore, it is crucial to clarify the relationship between m6A-mediated regulation of ferroptosis in cancer progression, providing a new strategy for cancer treatment with substantial clinical implications.

The Role of M6A LncRNA Modification in Papillary Thyroid Cancer

Thyroid Cancer (TC) is the most common endocrine cancer, of which papillary thyroid cancer (PTC), a well-differentiated type of TC, accounts for 80-90%. Long non-coding RNAs (lncRNAs), which comprise non-protein-coding segments of the genome, have been found to play a crucial role in various biological processes, including cancer development. The activity of lncRNAs is modified through epigenetic modifications, with N6-Methyladenosine (m6A) modifications implicated in the progression of several malignancies. The activity of m6A is further regulated by modifying enzymes classified as "readers", writers", and "erasers", of which specific enzymes have been found to play a role in various aspects of PTC. Recent research has highlighted the significance of m6A modification in regulating the expression and function of lncRNAs associated with PTC pathogenesis. Dysregulation of this process implicates tumor proliferation, invasion, and metastasis, with subsequent impact on prognosis. Therefore, understanding the interplay between m6A modification and lncRNAs provides valuable insights into the molecular mechanisms underlying PTC progression. This narrative review aims to explore the established role of several prominent m6A modifying enzymes and lncRNAs on cancer pathogenesis and seeks to clarify the function of these enzymes in PTC pathogenesis.

Potential role and therapeutic implications of glutathione peroxidase 4 in the treatment of Alzheimer's disease

Alzheimer's disease is an age-related neurodegenerative disorder with a complex and incompletely understood pathogenesis. Despite extensive research, a cure for Alzheimer's disease has not yet been found. Oxidative stress mediates excessive oxidative responses, and its involvement in Alzheimer's disease pathogenesis as a primary or secondary pathological event is widely accepted. As a member of the selenium-containing antioxidant enzyme family, glutathione peroxidase 4 reduces esterified phospholipid hydroperoxides to maintain cellular redox homeostasis. With the discovery of ferroptosis, the central role of glutathione peroxidase 4 in anti-lipid peroxidation in several diseases, including Alzheimer's disease, has received widespread attention. Increasing evidence suggests that glutathione peroxidase 4 expression is inhibited in the Alzheimer's disease brain, resulting in oxidative stress, inflammation, ferroptosis, and apoptosis, which are closely associated with pathological damage in Alzheimer's disease. Several therapeutic approaches, such as small molecule drugs, natural plant products, and non-pharmacological treatments, ameliorate pathological damage and cognitive function in Alzheimer's disease by promoting glutathione peroxidase 4 expression and enhancing glutathione peroxidase 4 activity. Therefore, glutathione peroxidase 4 upregulation may be a promising strategy for the treatment of Alzheimer's disease. This review provides an overview of the gene structure, biological functions, and regulatory mechanisms of glutathione peroxidase 4, a discussion on the important role of glutathione peroxidase 4 in pathological events closely related to Alzheimer's disease, and a summary of the advances in small-molecule drugs, natural plant products, and non-pharmacological therapies targeting glutathione peroxidase 4 for the treatment of Alzheimer's disease. Most prior studies on this subject used animal models, and relevant clinical studies are lacking. Future clinical trials are required to validate the therapeutic effects of strategies targeting glutathione peroxidase 4 in the treatment of Alzheimer's disease.

The Oncogenic Role of UBXN1 in Gastric Cancer Is Attributed to the METTL16-Mediated m6A Methylation and Histone Modifications

BACKGROUND

Multiple epigenetic regulatory mechanisms are crucial in tumorigenesis and development. However, the synergistic relationship between N6-methyladenosine (m6A) and histone modifications in regulating gene expression of gastric cancer (GC) requires further investigation.

RESULTS

Here, based on the microarray, RNA-seq, and survival analysis data, the m6A methyltransferase METTL16 was identified as a potential tumorigenic factor of GC. The silence of METTL16 suppresses the malignant phenotype of GC cells, and the NF-κB pathway was activated. By using the weighted correlation network analysis (WGCNA) and integrating RNA-seq and MeRIP-seq data, it was found that METTL16 is significantly positively correlated with UBX domain protein 1 (UBXN1). Furthermore, through the MeRIP-qPCR and dual-luciferase reporter assays, we found that knocking down METTL16 reduced the m6A modification level of the UBXN1 coding sequence in GC. Interestingly, the silencing of METTL16 also downregulated UBXN1 expression by promoting H3K36me3 modification at the UBXN1 promoter. Subsequent investigations found that the silencing of METTL16 upregulated the expression of the major H3K36me3 methyltransferase SETD2 in GC cells by methylating the m6A site in the mRNA coding sequence of SETD2.

CONCLUSIONS

Our findings demonstrate the spatio-temporal regulation of UBXN1 expression in GC cells by METTL16 through a combination of transcriptional and post-transcriptional mechanisms. The synergistic interplay of these various epigenetic mechanisms provides new prospects for tumor diagnosis and precision treatment.

Protein kinase A regulates ferroptosis by controlling GPX4 m6A modification through phosphorylation of ALKBH5

GPX4-dependent ferroptosis has emerged as a therapeutic strategy for cancer treatment. Here, we demonstrated that protein kinase A (PKA) participates in the regulation of ferroptosis by controlling the m6A modification of GPX4 in an ALKBH5-dependent manner. Notably, we identified ALKBH5, an m6A demethylase, as a novel target of PKA, which drives phosphorylation-dependent degradation of ALKBH5 protein. Moreover, the deletion of ALKBH5 represses ferroptotic cell death by maintaining GPX4 m6A modification and stability. Thus, by regulating ALKBH5-dependent GPX4 stability, PKA acts as a key regulator of ferroptosis. Our study unveils the involvement of PKA in m6A modification, which could control GPX4-dependent ferroptosis and tumor progression.

The diverse landscape of RNA modifications in cancer development and progression

BACKGROUND

RNA modifications, a central aspect of epitranscriptomics, add a regulatory layer to gene expression by modifying RNA function without altering nucleotide sequences. These modifications play vital roles across RNA species, influencing RNA stability, translation, and interaction dynamics, and are regulated by specific enzymes that add, remove, and interpret these chemical marks.

OBJECTIVE

This review examines the role of aberrant RNA modifications in cancer progression, exploring their potential as diagnostic and prognostic biomarkers and as therapeutic targets. We focus on how altered RNA modification patterns impact oncogenes, tumor suppressor genes, and overall tumor behavior.

METHODS

We performed an in-depth analysis of recent studies and advances in RNA modification research, highlighting key types and functions of RNA modifications and their roles in cancer biology. Studies involving preclinical models targeting RNA-modifying enzymes were reviewed to assess therapeutic efficacy and potential clinical applications.

RESULTS

Aberrant RNA modifications were found to significantly influence cancer initiation, growth, and metastasis. Dysregulation of RNA-modifying enzymes led to altered gene expression profiles in oncogenes and tumor suppressors, correlating with tumor aggressiveness, patient outcomes, and response to immunotherapy. Notably, inhibitors of these enzymes demonstrated potential in preclinical models by reducing tumor growth and enhancing the efficacy of existing cancer treatments.

CONCLUSIONS

RNA modifications present promising avenues for cancer diagnosis, prognosis, and therapy. Understanding the mechanisms of RNA modification dysregulation is essential for developing targeted treatments that improve patient outcomes. Further research will deepen insights into these pathways and support the clinical translation of RNA modification-targeted therapies.

N6-methyladenosine RNA modification regulates the transcription of SLC7A11 through KDM6B and GATA3 to modulate ferroptosis

BACKGROUND

Recent studies indicate that N6-methyladenosine (m6A) RNA modification may regulate ferroptosis in cancer cells, while its molecular mechanisms require further investigation.

METHODS

Liquid Chromatography-Tandem Mass Spectrometry (HPLC/MS/MS) was used to detect changes in m6A levels in cells. Transmission electron microscopy and flow cytometry were used to detect mitochondrial reactive oxygen species (ROS). RNA sequencing (RNA-seq) was employed to analyze the factors regulating ferroptosis. Chromatin immunoprecipitation (ChIP) was used to assess the binding of regulatory factors to the SLC7A11 promoter, and a Dual-Luciferase reporter assay measured promoter activity of SLC7A11. The dm6ACRISPR system was utilized for the demethylation of specific transcripts. The Cancer Genome Atlas Program (TCGA) database and immunohistochemistry validated the role of the METTL3/SLC7A11 axis in cancer progression.

RESULTS

The m6A methyltransferase METTL3 was upregulated during cancer cell ferroptosis and facilitated erastin-induced ferroptosis by enhancing mitochondrial ROS. Mechanistic studies showed that METTL3 negatively regulated the transcription and promoter activity of SLC7A11. Specifically, METTL3 induced H3K27 trimethylation of the SLC7A11 promoter by suppressing the mRNA stability of H3K27 demethylases KDM6B. Furthermore, METTL3 suppressed the expression of GATA3, which regulated SLC7A11 transcription by binding to the putative site at - 597 to - 590 of the SLC7A11 promoter. METTL3 decreased the precursor mRNA stability of GATA3 through m6A/YTHDF2-dependent recruitment of the 3'-5' exoribonuclease Dis3L2. Targeted demethylation of KDM6B and GATA3 m6A using the dm6ACRISPR system significantly increased the expression of SLC7A11. Moreover, the transcription factor YY1 was responsible for erastin-induced upregulation of METTL3 by binding to its promoter-proximal site. In vivo and clinical data supported the positive roles of the METTL3/SLC7A11 axis in tumor growth and progression.

CONCLUSIONS

METTL3 regulated the transcription of SLC7A11 through GATA3 and KDM6B to modulate ferroptosis in an m6A-dependent manner. This study provides a novel potential strategy and experimental support for the future treatment of cancer.

The Role of Methylation in Ferroptosis

Methylation modification is a crucial epigenetic alteration encompassing RNA methylation, DNA methylation, and histone methylation. Ferroptosis represents a newly discovered form of programmed cell death (PCD) in 2012, which is characterized by iron-dependent lipid peroxidation. The comprehensive investigation of ferroptosis is therefore imperative for a more profound comprehension of the pathological and pathophysiological mechanisms implicated in a wide array of diseases. Researches show that methylation modifications can exert either promotive or inhibitory effects on cell ferroptosis. Consequently, this review offers a comprehensive overview of the pivotal role played by methylation in ferroptosis, elucidating its associated factors and underlying mechanisms.

RNA methylation and breast cancer: insights into m6A, m7G and m5C

Breast cancer remains the most commonly diagnosed cancer in female worldwide, marked by its molecular diversity and complex subtypes. Despite progress in targeted therapies, tumor heterogeneity and treatment resistance continue to present major challenges. Recent studies emphasize the crucial role of RNA modifications in cancer biology, with nearly 200 distinct modifications identified. Among these, methylation is particularly significant, with methylation-related factors emerging as key regulators of RNA metabolism, influencing cancer progression, metastasis, and treatment resistance. This review focuses on the roles of key RNA methylation in breast cancer, particularly N6-methyladenosine (m6A), N7-methylguanosine (m7G), 5-methylcytosine (m5C), N1-methyladenosine (m1A), and N3-methylcytidine (m3C). We examine the functions of m6A "writers" like METTL3 and METTL14, and "readers" such as the YTH domain family in modulating tumor behavior. Dysregulation of m6A "erasers" like FTO and ALKBH5 are noticed too, highlighting their impact on cancer stem cell phenotypes, chemoresistance, and immune evasion. Additionally, the role of m7G modifications in mRNA stability and translation, facilitated by METTL1/WDR4 and RNMT, is discussed as a potential therapeutic target. The involvement of m5C, m1A, and m3C modifications, particularly those mediated by NSUN2 and NSUN6, in breast cancer tumorigenesis and prognosis is also reviewed. Despite coding RNAs, the interplay between these RNA methylations and non-coding RNAs, such as lncRNAs and miRNAs, is explored, shedding light on their roles in cancer cell proliferation, invasion, and immune response modulation. This review highlights the potential of RNA methylations as novel therapeutic targets in breast cancer, offering insights for precision medicine and improved patient outcomes.

The m6A-independent role of epitranscriptomic factors in cancer

Protein function alteration and protein mislocalization are cancer hallmarks that drive oncogenesis. N6-methyladenosine (m6A) deposition mediated by METTL3, METTL16, and METTL5 together with the contribution of additional subunits of the m6A system, has shown a dramatic impact on cancer development. However, the cellular localization of m6A proteins inside tumor cells has been little studied so far. Interestingly, recent evidence indicates that m6A methyltransferases are not always confined to the nucleus, suggesting that epitranscriptomic factors may also have multiple oncogenic roles beyond m6A that still represent an unexplored field. To date novel epigenetic drugs targeting m6A modifiers, such as METTL3 inhibitors, are entering into clinical trials, therefore, the study of the potential onco-properties of m6A effectors beyond m6A is required. Here we will provide an overview of methylation-independent functions of the m6A players in cancer, describing the molecular mechanisms involved and the future implications for therapeutics.

TFAP2C/FLT3 axis reduces ferroptosis in breast cancer cells by inhibiting mitochondrial autophagy

BACKGROUND

FMS-like tyrosine kinase 3 (FLT3), a key target protein for treating acute myeloid leukemia, has recently been found to be closely related to ferroptosis in breast cancer (BC). However, the mechanism by which FLT3 regulates ferroptosis in BC remains unknown. Whether this regulatory relationship can be exploited for BC treatment needs further exploration.

METHODS

This study combined analysis from The Cancer Genome Atlas database with immunohistochemistry/quantitative reverse transcription-PCR/Western blot experiments to verify the expression of FLT3 in BC. FLT3 knockdown/overexpression plasmids were used in conjunction with mitochondrial autophagy inducers to treat BC cells, analyzing the effects of FLT3 on autophagy and ferroptosis. Key transcription factors for FLT3 were determined through predictions from the KnockTF database and dual luciferase/chromatin immunoprecipitation experiments, further analyzing the impact of this regulatory axis on autophagy and ferroptosis in BC cells.

RESULTS

FLT3 was significantly overexpressed in BC tissues and cells. Overexpression of FLT3 could inhibit autophagy and ferroptosis in BC cells, a regulation that was restored upon the addition of mitochondrial autophagy inducers. Additionally, transcription factor AP-2 gamma (TFAP2C) could mediate the transcriptional activation of FLT3, further inhibiting ferroptosis induced by mitochondrial autophagy.

CONCLUSION

The TFAP2C/FLT3 axis reduced ferroptosis in BC cells by inhibiting mitochondrial autophagy. These research findings elucidated the mechanism by which FLT3 regulated ferroptosis in BC and provided potential targets for BC treatment.

The regulatory mechanisms of N6-methyladenosine modification in ferroptosis and its implications in disease pathogenesis

HEADING AIMS

Based on the current knowledge of the molecular mechanisms by which m6A influences ferroptosis, our objective is to underscore the intricate and interdependent relationships between m6A and the principal regulatory pathways of ferroptosis, as well as other molecules, emphasizing its relevance to diseases associated with this cell death mode.

MATERIALS AND METHODS

We conducted a literature search using the keywords "m6A and ferroptosis" across PubMed, Web of Science, and Medline. The search was limited to English-language publications from 2017 to 2024. Retrieved articles were managed using Endnote software. Two authors independently screened the search results and reviewed the full texts of selected articles.

KEY FINDINGS

Abnormal m6A levels are often identified as critical regulators of ferroptosis. Specifically, "writers", "readers" and "erasers" that dynamically modulate m6A function regulate various pathways in ferroptosis including iron metabolism, lipid metabolism and antioxidant system. Additionally, we provide an overview of the role of m6A-mediated ferroptosis in multiple diseases and summarize the potential applications of m6A-mediated ferroptosis, including its use as a therapeutic target for diseases and as diagnostic as well as prognostic biomarkers.

SIGNIFICANCE

N6-methyladenosine (m6A) modification, a prevalent RNA modification in eukaryotic cells, is crucial in regulating various aspects of RNA metabolism. Notably, accumulating evidence has implicated m6A modification in ferroptosis, a form of iron-dependent cell death characterized by elevated iron levels and lipid peroxide accumulation. Overall, this review sheds light on the potential diagnostic and therapeutic applications of m6A regulators in addressing conditions associated with ferroptosis.

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.

METTL protein family: focusing on the occurrence, progression and treatment of cancer

Methyltransferase-like protein is a ubiquitous enzyme-like protein in the human body, with binding domains for nucleic acids, proteins and other small molecules, and plays an important role in a variety of biological behaviours in normal organisms and diseases, characterised by the presence of a methyltransferase-like structural domain and a structurally conserved SAM-binding domain formed by the seven-stranded β-fold structure in the center of the protein. With the deepening of research, the METTL protein family has been found to be abnormally expressed in a variety of tumor diseases, and the clarification of its relationship with tumor diseases can be used as a molecular therapeutic target and has an important role in the prognosis of tumors. In this paper, we review the structure, biological process, immunotherapy, drug-targeted therapy, and markers of the METTL protein family to provide new ideas for the diagnosis and treatment of tumors.

Methyl-Transferase-Like Protein 16 (METTL16): The Intriguing Journey of a Key Epitranscriptomic Player Becoming an Emerging Biological Target

Key epitranscriptomic players have been increasingly characterized for their structural features and their involvement in several diseases. Accordingly, the design and synthesis of novel epitranscriptomic modulators have started opening a glimmer for drug discovery. m6A is a reversible modification occurring on a specific site and is catalyzed by three sets of proteins responsible for opposite functions. Writers (e.g., methyl-transferase-like protein (METTL) 3/METTL14 complex and METTL16) introduce the methyl group on adenosine N-6, by transferring the methyl group from the methyl donor S-adenosyl-methionine (SAM) to the substrate. Despite the rapidly advancing drug discovery progress on METTL3/METTL14, the METTL16 m6A writer has been marginally explored so far. We herein provide the first comprehensive overview of structural and biological features of METTL16, highlighting the state of the art in the field of its biological and structural characterization. We also showcase initial efforts in the identification of structural templates and preliminary structure-activity relationships for METTL16 modulators.

Multifaceted bioinformatic analysis of m6A-related ferroptosis and its link with gene signatures and tumour-infiltrating immune cells in gliomas

Whether N6-Methyladenosine (m6A)- and ferroptosis-related genes act on immune responses to regulate glioma progression remains unanswered. Data of glioma and corresponding normal brain tissues were fetched from the TCGA database and GTEx. Differentially expressed genes (DEGs) were identified for GO and KEGG enrichment analyses. The FerrDb database was based to yield ferroptosis-related DEGs. Hub genes were then screened out using the cytoHubba database and validated in clinical samples. Immune cells infiltrating into the glioma tissues were analysed using the CIBERSORT R script. The association of gene signature underlying the m6A-related ferroptosis with tumour-infiltrating immune cells and immune checkpoints in low-grade gliomas was analysed. Of 6298 DEGs enriched in mRNA modifications, 144 were ferroptosis-related; NFE2L2 and METTL16 showed the strongest positive correlation. METTL16 knockdown inhibited the migrative and invasive abilities of glioma cells and induced ferroptosis in vitro. NFE2L2 was enriched in the anti-m6A antibody. Moreover, METTL16 knockdown reduced the mRNA stability and level of NFE2L2 (both p < 0.05). Proportions of CD8+ T lymphocytes, activated mast cells and M2 macrophages differed between low-grade gliomas and normal tissues. METTL16 expression was negatively correlated with CD8+ T lymphocytes, while that of NFE2L2 was positively correlated with M2 macrophages and immune checkpoints in low-grade gliomas. Gene signatures involved in the m6A-related ferroptosis in gliomas were identified via bioinformatic analyses. NFE2L2 interacted with METTL16 to regulate the immune response in low-grade gliomas, and both molecules may be novel therapeutic targets for gliomas.

Role of N6-methyladenosine RNA modification in cancer

N6-methyladenosine (m6A) is the most abundant modification of RNA in eukaryotic cells. Previous studies have shown that m6A is pivotal in diverse diseases especially cancer. m6A corelates with the initiation, progression, resistance, invasion, and metastasis of cancer. However, despite these insights, a comprehensive understanding of its specific roles and mechanisms within the complex landscape of cancer is still elusive. This review begins by outlining the key regulatory proteins of m6A modification and their posttranslational modifications (PTMs), as well as the role in chromatin accessibility and transcriptional activity within cancer cells. Additionally, it highlights that m6A modifications impact cancer progression by modulating programmed cell death mechanisms and affecting the tumor microenvironment through various cancer-associated immune cells. Furthermore, the review discusses how microorganisms can induce enduring epigenetic changes and oncogenic effect in microorganism-associated cancers by altering m6A modifications. Last, it delves into the role of m6A modification in cancer immunotherapy, encompassing RNA therapy, immune checkpoint blockade, cytokine therapy, adoptive cell transfer therapy, and direct targeting of m6A regulators. Overall, this review clarifies the multifaceted role of m6A modification in cancer and explores targeted therapies aimed at manipulating m6A modification, aiming to advance cancer research and improve patient outcomes.

METTL16 regulates the mRNA stability of FBXO5 via m6A modification to facilitate the malignant behavior of breast cancer

BACKGROUND

N6-methyladenosine (m6A) regulates the progression of breast cancer (BC). We aimed to investigate the action and mechanism involved of methyltransferase-like protein 16 (METTL16) in BC growth and metastasis.

METHODS

RT-qPCR, immunoblotting, and IHC were performed to test the levels of gene expression. CCK-8, clone formation, wound healing, and transwell assays were applied to measure the cell proliferation, migration, and invasion. m6A RNA methylation and MeRIP assay were utilized to confirm the m6A level of total RNA and FBXO5 mRNA. RIP was utilized to ascertain the interaction between METTL16 and FBXO5 mRNA. The in vivo murine subcutaneous tumor and metastasis model were constructed to further confirm the action of METTL16.

RESULTS

METTL16 was overexpression in BC cells and tissues. Inhibition of METTL16 restrained the growth and metastasis of BC. Furthermore, the METTL16 level and FBXO5 level was positively correlated in BC tissues, and METTL16 aggrandized the stability of FBXO5 mRNA depending on the m6A modification. Overexpression of FBXO5 antagonized the restrained function of METTL16 knockdown on BC cells' proliferation, migration, invasion, and EMT.

CONCLUSION

METTL16 boosts the mRNA stability of FBXO5 via m6A modification to facilitate the malignant action of BC in vitro and in vivo, offering new latent targets for cure of BC.

Ferroptosis resistance in cancer cells: nanoparticles for combination therapy as a solution

Ferroptosis is a form of regulated cell death (RCD) characterized by iron-dependent lipid peroxidation. Ferroptosis is currently proposed as one of the most promising means of combating tumor resistance. Nevertheless, the problem of ferroptosis resistance in certain cancer cells has been identified. This review first, investigates the mechanisms of ferroptosis induction in cancer cells. Next, the problem of cancer cell resistance to ferroptosis, as well as the underlying mechanisms is discussed. Recently discovered ferroptosis-suppressing biomarkers have been described. The various types of nanoparticles that can induce ferroptosis are also discussed. Given the ability of nanoparticles to combine multiple agents, this review proposes nanoparticle-based ferroptosis cell death as a viable method of circumventing this resistance. This review suggests combining ferroptosis with other forms of cell death, such as apoptosis, cuproptosis and autophagy. It also suggests combining ferroptosis with immunotherapy.

Ferroptosis: a critical mechanism of N6-methyladenosine modification involved in carcinogenesis and tumor progression

Ferroptosis is an iron-dependent regulatory cell necrosis induced by iron overload and lipid peroxidation. It occurs when multiple redox-active enzymes are ectopically expressed or show abnormal function. Hence, the precise regulation of ferroptosis-related molecules is mediated across multiple levels, including transcriptional, posttranscriptional, translational, and epigenetic levels. N6-methyladenosine (m6A) is a highly evolutionarily conserved epigenetic modification in mammals. The m6A modification is commonly linked to tumor proliferation, progression, and therapy resistance because it is involved in RNA metabolic processes. Intriguingly, accumulating evidence suggests that dysregulated ferroptosis caused by the m6A modification drives tumor development. In this review, we summarized the roles of m6A regulators in ferroptosis-mediated malignant tumor progression and outlined the m6A regulatory mechanism involved in ferroptosis pathways. We also analyzed the potential value and application strategies of targeting m6A/ferroptosis pathway in the clinical diagnosis and therapy of tumors.

Epigenetic deregulation in breast cancer microenvironment: Implications for tumor progression and therapeutic strategies

Breast cancer comprises a substantial proportion of cancer diagnoses in women and is a primary cause of cancer-related mortality. While hormone-responsive cases generally have a favorable prognosis, the aggressive nature of triple-negative breast cancer presents challenges, with intrinsic resistance to established treatments being a persistent issue. The complexity intensifies with the emergence of acquired resistance, further complicating the management of breast cancer. Epigenetic changes, encompassing DNA methylation, histone and RNA modifications, and non-coding RNAs, are acknowledged as crucial contributors to the heterogeneity of breast cancer. The unique epigenetic landscape harbored by each cellular component within the tumor microenvironment (TME) adds great diversity to the intricate regulations which influence therapeutic responses. The TME, a sophisticated ecosystem of cellular and non-cellular elements interacting with tumor cells, establishes an immunosuppressive microenvironment and fuels processes such as tumor growth, angiogenesis, and extracellular matrix remodeling. These factors contribute to challenging conditions in cancer treatment by fostering a hypoxic environment, inducing metabolic stress, and creating physical barriers to drug delivery. This article delves into the complex connections between breast cancer treatment response, underlying epigenetic changes, and vital interactions within the TME. To restore sensitivity to treatment, it emphasizes the need for combination therapies considering epigenetic changes specific to individual members of the TME. Recognizing the pivotal role of epigenetics in drug resistance and comprehending the specificities of breast TME is essential for devising more effective therapeutic strategies. The development of reliable biomarkers for patient stratification will facilitate tailored and precise treatment approaches.

Targeting epigenetic and posttranslational modifications regulating ferroptosis for the treatment of diseases

Ferroptosis, a unique modality of cell death with mechanistic and morphological differences from other cell death modes, plays a pivotal role in regulating tumorigenesis and offers a new opportunity for modulating anticancer drug resistance. Aberrant epigenetic modifications and posttranslational modifications (PTMs) promote anticancer drug resistance, cancer progression, and metastasis. Accumulating studies indicate that epigenetic modifications can transcriptionally and translationally determine cancer cell vulnerability to ferroptosis and that ferroptosis functions as a driver in nervous system diseases (NSDs), cardiovascular diseases (CVDs), liver diseases, lung diseases, and kidney diseases. In this review, we first summarize the core molecular mechanisms of ferroptosis. Then, the roles of epigenetic processes, including histone PTMs, DNA methylation, and noncoding RNA regulation and PTMs, such as phosphorylation, ubiquitination, SUMOylation, acetylation, methylation, and ADP-ribosylation, are concisely discussed. The roles of epigenetic modifications and PTMs in ferroptosis regulation in the genesis of diseases, including cancers, NSD, CVDs, liver diseases, lung diseases, and kidney diseases, as well as the application of epigenetic and PTM modulators in the therapy of these diseases, are then discussed in detail. Elucidating the mechanisms of ferroptosis regulation mediated by epigenetic modifications and PTMs in cancer and other diseases will facilitate the development of promising combination therapeutic regimens containing epigenetic or PTM-targeting agents and ferroptosis inducers that can be used to overcome chemotherapeutic resistance in cancer and could be used to prevent other diseases. In addition, these mechanisms highlight potential therapeutic approaches to overcome chemoresistance in cancer or halt the genesis of other diseases.

m6A and m5C modification of GPX4 facilitates anticancer immunity via STING activation

Cancer immunotherapy is arguably the most rapidly advancing realm of cancer treatment. Glutathione peroxidase 4 (GPX4) has emerged as the vital enzyme to prevent lipid peroxidation and maintain cellular redox homeostasis. However, the mechanism of GPX4 in the regulation of cancer immunotherapy of colon adenocarcinoma (COAD) are incompletely understood. In pan-cancer analysis, we found that GPX4 showed remarkably upregulated expression and exhibited significant association with overall survival in multiple cancer types, especially COAD. Furthermore, upregulated GPX4 expression was positively correlated with increased immune cells infiltration and enhanced expression of immunomodulators. Mechanistically, RBM15B- and IGFBP2-mediated N6-methyladenosine (m6A) modification and NSUN5-mediated 5-methylcytosine (m5C) modification of GPX4 facilitated anticancer immunity via activation of cyclic GMP-AMP synthase (cGAS)-stimulator of interferon (STING) signaling by maintaining redox homeostasis in COAD. The risk model and nomogram model constructed based on the GPX4-derived genes further confirmed the prognostic and treatment-guiding value of GPX4. In all, our study demonstrated that m6A and m5C modification of GPX4 may be a promising target for cancer immunotherapy via activating the cGAS-STING signaling pathway in COAD.

Unleashing the Power of Yes-Associated Protein in Ferroptosis and Drug Resistance in Breast Cancer, with a Special Focus on Therapeutic Strategies

The YAP protein is a critical oncogenic mediator within the Hippo signaling pathway and has been implicated in various cancer types. In breast cancer, it frequently becomes activated, thereby contributing to developing drug-resistance mechanisms. Recent studies have underscored the intricate interplay between YAP and ferroptosis within the breast tumor microenvironment. YAP exerts a negative regulatory effect on ferroptosis, promoting cancer cell survival and drug resistance. This review offers a concise summary of the current understanding surrounding the interplay between the YAP pathway, ferroptosis, and drug-resistance mechanisms in both bulk tumor cells and cancer stem cells. We also explore the potential of natural compounds alone or in combination with anticancer therapies for targeting the YAP pathway in treating drug-resistant breast cancer. This approach holds the promise of enhancing the effectiveness of current treatments and paving the way for developing novel therapeutics.

Compounds targeting ferroptosis in breast cancer: progress and their therapeutic potential

In recent years, there has been a significant increase in the incidence of Breast cancer (BC), making it the most common cancer among women and a major threat to women's health. Consequently, there is an urgent need to discover new and effective strategies for treating BC. Ferroptosis, a novel form of cell death characterized by the accumulation of iron-dependent lipid reactive oxygen species, has emerged as a distinct regulatory pathway separate from necrosis, apoptosis, and autophagy. It is widely recognized as a crucial factor in the development and progression of cancer, offering a promising avenue for BC treatment. While significant progress has been made in understanding the mechanisms of ferroptosis in BC, drug development is still in its early stages. Numerous compounds, including phytochemicals derived from dietary sources and medicinal plants, as well as synthetic drugs (both clinically approved medications and laboratory reagents), have shown the ability to induce ferroptosis in BC cells, effectively inhibiting tumor growth. This comprehensive review aims to examine in detail the compounds that target ferroptosis in BC and elucidate their potential mechanisms of action. Additionally, the challenges associated with the clinical application of ferroptosis-inducing drugs are discussed, offering valuable insights for the development of novel treatment strategies for BC.

The RNA methyltransferase METTL16 enhances cholangiocarcinoma growth through PRDM15-mediated FGFR4 expression

BACKGROUND

RNA N6-Methyladenosine (m6A) modification is implicated in the progression of human cancers including cholangiocarcinoma (CCA). METTL16 is recently identified as a new RNA methyltransferase responsible for m6A modification, although the role of METTL16 in CCA has not yet been examined. The current study aims to investigate the effect and mechanism of the RNA methyltransferase METTL16 in CCA.

METHODS

The expression of METTL16 in CCA was examined by analyzing publicly available datasets or by IHC staining on tumor samples. siRNA or CRISPR/Cas9-mediated loss of function studies were performed in vitro and in vivo to investigate the oncogenic role of METTL16 in CCA. MeRIP-Seq was carried out to identify the downstream target of METTL16. ChIP-qPCR, immunoprecipitation, and immunoblots were used to explore the regulation mechanisms for METTL16 expression in CCA.

RESULTS

We observed that the expression of METTL16 was noticeably increased in human CCA tissues. Depletion of METTL16 significantly inhibited CCA cell proliferation and decreased tumor progression. PRDM15 was identified as a key target of METTL16 in CCA cells. Mechanistically, our data showed that METTL16 regulated PRDM15 protein expression via YTHDF1-dependent translation. Accordingly, we observed that restoration of PRDM15 expression could rescue the deficiency of CCA cell proliferation/colony formation induced by METTL16 depletion. Our subsequent analyses revealed that METTL16-PRDM15 signaling regulated the expression of FGFR4 in CCA cells. Specifically, we observed that PRDM15 protein was associated with the FGFR4 promoter to regulate its expression. Furthermore, we showed that the histone acetyltransferase p300 cooperated with the transcription factor YY1 to regulate METTL16 gene expression via histone H3 lysine 27 (H3K27) acetylation in CCA cells.

CONCLUSIONS

This study describes a novel METTL16-PRDM15-FGFR4 signaling axis which is crucial for CCA growth and may have important therapeutic implications. We showed that depletion of METTL16 significantly inhibited CCA cell proliferation and decreased tumor progression.

Regulation of m6A modification on ferroptosis and its potential significance in radiosensitization

Radiotherapy is often used to treat various types of cancers, but radioresistance greatly limits the clinical efficiency. Recent studies have shown that radiotherapy can lead to ferroptotic cancer cell deaths. Ferroptosis is a new type of programmed cell death caused by excessive lipid peroxidation. The induction of ferroptosis provides a potential therapeutic strategy for radioresistance. As the most common post-transcriptional modification of mRNA, m6A methylation is widely involved in the regulation of various physiopathological processes by regulating RNA function. Dynamic m6A modification controlled by m6A regulatory factors also affects the susceptibility of cells to ferroptosis, thereby determining the radiosensitivity of tumor cells to radiotherapy. In this review, we summarize the mechanism and significance of radiotherapy induced ferroptosis, analyze the regulatory characteristics of m6A modification on ferroptosis, and discuss the possibility of radiosensitization by enhancing m6A-mediated ferroptosis. Clarifying the regulation of m6A modification on ferroptosis and its significance in the response of tumor cells to radiotherapy will help us identify novel targets to improve the efficacy of radiotherapy and reduce or overcome radioresistance.

Ghost authors revealed: The structure and function of human N6 -methyladenosine RNA methyltransferases

Despite the discovery of modified nucleic acids nearly 75 years ago, their biological functions are still being elucidated. N6 -methyladenosine (m6 A) is the most abundant modification in eukaryotic messenger RNA (mRNA) and has also been detected in non-coding RNAs, including long non-coding RNA, ribosomal RNA, and small nuclear RNA. In general, m6 A marks can alter RNA secondary structure and initiate unique RNA-protein interactions that can alter splicing, mRNA turnover, and translation, just to name a few. Although m6 A marks in human RNAs have been known to exist since 1974, the structures and functions of methyltransferases responsible for writing m6 A marks have been established only recently. Thus far, there are four confirmed human methyltransferases that catalyze the transfer of a methyl group from S-adenosylmethionine (SAM) to the N6 position of adenosine, producing m6 A: methyltransferase-like protein (METTL) 3/METTL14 complex, METTL16, METTL5, and zinc-finger CCHC-domain-containing protein 4. Though the methyltransferases have unique RNA targets, all human m6 A RNA methyltransferases contain a Rossmann fold with a conserved SAM-binding pocket, suggesting that they utilize a similar catalytic mechanism for methyl transfer. For each of the human m6 A RNA methyltransferases, we present the biological functions and links to human disease, RNA targets, catalytic and kinetic mechanisms, and macromolecular structures. We also discuss m6 A marks in human viruses and parasites, assigning m6 A marks in the transcriptome to specific methyltransferases, small molecules targeting m6 A methyltransferases, and the enzymes responsible for hypermodified m6 A marks and their biological functions in humans. Understanding m6 A methyltransferases is a critical steppingstone toward establishing the m6 A epitranscriptome and more broadly the RNome. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Recognition RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.

RNA Methyltransferase METTL16's Protein Domains Have Differential Functional Effects on Cell Processes

METTL16, a human m6A RNA methyltransferase, is currently known for its modification of U6 and MAT2A RNAs. Several studies have identified additional RNAs to which METTL16 binds, however whether METTL16 modifies these RNAs is still in question. Moreover, a recent study determined that METTL16 contains more than one RNA-binding domain, leaving the importance of each individual RNA-binding domain unknown. Here we examined the effects of mutating the METTL16 protein in certain domains on overall cell processes. We chose to mutate the N-terminal RNA-binding domain, the methyltransferase domain, and the C-terminal RNA-binding domain. With these mutants, we identified changes in RNA-binding ability, protein and RNA expression, cell cycle phase occupancy, and proliferation. From the resulting changes in RNA and protein expression, we saw effects on cell cycle, metabolism, intracellular transport, and RNA processing pathways, which varied between the METTL16 mutant lines. We also saw significant effects on the G1 and S phase occupancy times and proliferative ability with some but not all the mutants. We have therefore concluded that while METTL16 may or may not m6A-modify all RNAs it binds, its binding (or lack of) has a significant outcome on a variety of cell processes.

The m6A methyltransferase METTL16 inhibits the proliferation of pancreatic adenocarcinoma cancer cells via the p21 signaling pathway

Background

Many studies have reported that N6-methyladenosine (m6A) modification plays a critical role in the epigenetic regulation of organisms and especially in the pathogenesis of malignant diseases. However, m6A research has mainly focused on methyltransferase activity mediated by METTL3, and few studies have focused on METTL16. The aim of this study was to investigate the mechanism of METTL16, which mediates m6A modification, and its role in pancreatic adenocarcinoma (PDAC) cell proliferation.

Methods

Clinicopathologic and survival data were retrospectively collected from 175 PDAC patients from multiple clinical centers to detect the expression of METTL16. CCK-8, cell cycle, EdU and xenograft mouse model experiments were used to evaluate the proliferation effect of METTL16. Potential downstream pathways and mechanisms were explored via RNA sequencing, m6A sequencing, and bioinformatic analyses. Regulatory mechanisms were studied through methyltransferase inhibition, RIP, MeRIP‒qPCR assays.

Results

We found that METTL16 expression was markedly downregulated in PDAC, and multivariate Cox regression analyses revealed that METTL16 was a protective factor for PDAC patients. We also demonstrated that METTL16 overexpression inhibited PDAC cell proliferation. Furthermore, we identified a METTL16-p21 signaling axis, with downregulation of METTL16 resulting in inhibition of CDKN1A (p21). Additionally, METTL16 silencing and overexpression experiments highlighted m6A modification alterations in PDAC.

Conclusions

METTL16 plays a tumor-suppressive role and suppresses PDAC cell proliferation through the p21 pathway by mediating m6A modification. METTL16 may be a novel marker of PDAC carcinogenesis and target for the treatment of PDAC.

Targeting GPX4 in human cancer: Implications of ferroptosis induction for tackling cancer resilience

Cancer metabolic alterations have been emphasized to protect cancer cells from cell death. The metabolic reprogramming toward a mesenchymal state makes cancer cells resistant to therapy but vulnerable to ferroptosis induction. Ferroptosis is a new form of regulated cell death based on the iron-dependent accumulation of excessive lipid peroxidation. Glutathione peroxidase 4 (GPX4) is the core regulator of ferroptosis by detoxifying cellular lipid peroxidation using glutathione as a cofactor. GPX4 synthesis requires selenium incorporation into the selenoprotein through isopentenylation and selenocysteine tRNA maturation. GPX4 synthesis and expression can be regulated by multiple levels of its transcription, translation, posttranslational modifications, and epigenetic modifications. Targeting GPX4 in cancer may be a promising strategy for effectively inducing ferroptosis and killing therapy-resistant cancer. Several pharmacological therapeutics targeting GPX4 have been developed constantly to activate ferroptosis induction in cancer. The potential therapeutic index of GPX4 inhibitors remains to be tested with thorough examinations of their safety and adverse effects in vivo and clinical trials. Many papers have been published continuously in recent years, requiring state-of-the-art updates in targeting GPX4 in cancer. Herein, we summarize targeting the GPX4 pathway in human cancer, which leads to implications of ferroptosis induction for tackling cancer resilience.

GPX4: The hub of lipid oxidation, ferroptosis, disease and treatment

Glutathione peroxidase 4 (GPx4) moonlights as structural protein and antioxidase that powerfully inhibits lipid oxidation. In the past years, it is considered as a key regulator of ferroptosis, which takes role in the lipid and amine acid metabolism and influences the cell aging, oncogenesis, and cell death. More and more evidences show that targeting GPX4-induced ferroptosis is a promising strategy for disease therapy, especially cancer treatment. In view of these, we generalize the function of GPX4 and regulatory mechanism between GPX4 and ferroptosis, discuss its roles in the disease pathology, and focus on the recent advances of disease therapeutic potential.

Roles of RNA Methylations in Cancer Progression, Autophagy, and Anticancer Drug Resistance

RNA methylations play critical roles in RNA processes, including RNA splicing, nuclear export, nonsense-mediated RNA decay, and translation. Regulators of RNA methylations have been shown to be differentially expressed between tumor tissues/cancer cells and adjacent tissues/normal cells. N6-methyladenosine (m6A) is the most prevalent internal modification of RNAs in eukaryotes. m6A regulators include m6A writers, m6A demethylases, and m6A binding proteins. Since m6A regulators play important roles in regulating the expression of oncogenes and tumor suppressor genes, targeting m6A regulators can be a strategy for developing anticancer drugs. Anticancer drugs targeting m6A regulators are in clinical trials. m6A regulator-targeting drugs could enhance the anticancer effects of current chemotherapy drugs. This review summarizes the roles of m6A regulators in cancer initiation and progression, autophagy, and anticancer drug resistance. The review also discusses the relationship between autophagy and anticancer drug resistance, the effect of high levels of m6A on autophagy and the potential values of m6A regulators as diagnostic markers and anticancer therapeutic targets.