METTL5 serves as a diagnostic and prognostic biomarker in hepatocellular carcinoma by influencing the immune microenvironment

Pan-cancer characterization of m6A-mediated regulation of T cell exhaustion dynamics and clinical relevancies in human cancers

T cell exhaustion (TEX) is a major barrier to effective immunotherapy. The role of N6-methyladenosine (m6A) modification in regulating immune cell function has been recognized, but its impact on TEX dynamics across cancer types and clinical outcomes remains unclear. Here, we conducted a pan-cancer analysis integrating multi-omics data from cell lines, single-cell RNA sequencing, and pan-cancer and immunotherapy datasets to explore the dynamic interplay between m6A modification and TEX. We found that m6A modification influences key TEX-associated genes at both the cellular and single-cell levels, with distinct expression patterns across the exhaustion spectrum. Based on m6A-TEX interactions, three pan-cancer subtypes were identified, each with unique molecular profiles, immune phenotypes, and survival outcomes. The TexLm6AL subtype, characterized by low m6A activity and low TEX, correlated with high immune infiltration, increased cytolytic activity, and favorable survival, whereas the TexLm6AH and TexHm6AH subtypes with higher m6A activity were associated with poorer survival. Multivariate analysis confirmed the prognostic value of this classification independent of traditional clinical factors. Moreover, m6A-TEX crosstalk influenced responses to immune checkpoint blockade therapies. Our findings provide novel insights into the role of m6A in TEX regulation and underscore the potential of m6A regulators as biomarkers and therapeutic targets for advancing cancer immunotherapy.

The role of N(6)-methyladenosine (m6a) modification in cancer: recent advances and future directions

N(6)-methyladenosine (m6A) modification is the most abundant and prevalent internal modification in eukaryotic mRNAs. The role of m6A modification in cancer has become a hot research topic in recent years and has been widely explored. m6A modifications have been shown to regulate cancer occurrence and progression by modulating different target molecules. This paper reviews the recent research progress of m6A modifications in cancer and provides an outlook on future research directions, especially the development of molecularly targeted drugs. See also the graphical abstract(Fig. 1).

Dust mite antigens endow dendritic cells with the capacity to induce a Th2 response by regulating their methylation profiles

BACKGROUND

It is well-known that Dendritic cells (DCs) are essential in the development of airway Th2 polarization and airway allergy (AA). The underlying mechanism is still not fully understood. The objective of this study is to examine the role of methyltransferase-like protein-5 (Mettl5), a methyltransferase involved in N6-methyladenosine (m6A) methylation, in altering DC's properties to facilitate the development of Th2 polarization and AA.

METHODS

Dust mite extracts (DME) were used as a specific antigen to establish an AA mouse model. The epigenetic status of DCs was examined using a Chromatin immunoprecipitation (ChIP) assay. A mouse strain carrying the Mettl5-deficient DCs was used to observe the role of Mettl5 in determining the phenotypes of DCs.

RESULTS

The results showed that the expression of Mettl5 was elevated in DCs, which was positively correlated with the AA response. The development of airway Th2 polarization was hindered by Mettl5 depletion in DCs. Mettl5 is involved in the transcription of the Timd4 gene in DCs caused by DME. The degradation of IRF5 by Mettl5 led to an increase in T cell immunoglobulin domain molecule-4 (TIM4) expression in DCs associated with DME. Inhibition of Mettl5 in DCs reconciled the DME-induced airway Th2 polarization and experimental AA.

CONCLUSIONS

Airway DCs from AA mice showed elevated amounts of Mettl5, which led to the expression of TIM4. The experimental AA was mitigated by Mettl5 inhibition.

Targeting methyltransferase-like 5-mediated sphingomyelin metabolism: A novel therapeutic approach in gastric cancer

Gastric cancer (GC) is a global health problem and a leading cause of cancer-related deaths, with its mortality rate ranking third among all cancers. The etiology and progression of GC are characterized by a complex interplay of genetic and epigenetic changes, which present challenges for its early diagnosis and effective treatment. Elucidating the mechanisms underlying the occurrence and development of GC and identifying novel biomarkers for early detection and prognosis are crucial to improving patient outcomes. This editorial examines the role of methyltransferase-like 5 (METTL5) in the progression of GC through sphingomyelin metabolism by considering an article published by Zhang et al in the World Journal of Gastrointestinal Oncology in 2024, which is entitled “METTL5 promotes GC progression via sphingomyelin metabolism”. These authors investigated the biological behavior of METTL5 in GC by examining its expression patterns, clinical relevance, functional effect, and potential mechanisms, as well as its response to chemotherapy. This editorial provides valuable insights into the role of METTL5 in the progression of GC and its potential as a therapeutic target.

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.

The novel m6A writer methyltransferase 5 is a promising prognostic biomarker and associated with immune cell infiltration in oral squamous cell carcinoma

BACKGROUND

Emerging research has identified the N6-methyladenosine (m6A) modification and its regulatory enzymes, including methyltransferase 5 (METTL5), as critical players in cancer biology. However, the role of METTL5 in oral squamous cell carcinoma (OSCC) remains poorly understood.

MATERIALS AND METHODS

We conducted a comprehensive study to investigate the expression and implications of METTL5 in OSCC. We recruited 76 OSCC patients to analyze METTL5 mRNA and protein expression using RT-qPCR and western blot. Additionally, we analyzed METTL5 expression and its correlation with clinical features, patient prognosis, immune cell infiltration, and biological pathways using the TCGA-HNSCC dataset, which primarily consists of OSCC samples.

RESULTS

Our findings revealed significant overexpression of METTL5 in OSCC tissues compared to normal tissues. The high expression of METTL5 is associated with advanced cancer stages, higher tumor grades, nodal metastasis, and poorer patient outcomes, indicating its involvement in cancer progression. In silico functional analysis revealed that METTL5 plays a role in multiple biological pathways, highlighting its importance in cancer biology. Moreover, METTL5 has complex relationships with immune regulatory genes, suggesting its potential role in shaping the tumor immune microenvironment.

CONCLUSION

METTL5 is a promising candidate for the prognosis and therapeutic intervention of OSCC. Its overexpression in cancer tissues, association with clinical features, and intricate links to immune regulatory networks underscore its significance in this malignancy. This study contributes to a deeper understanding of the complex factors influencing OSCC, and provides a foundation for future research and potential clinical applications.

The Role of m6A Methylation in Tumor Immunity and Immune-Associated Disorder

N6-methyladenosine (m6A) represents the most prevalent and significant internal modification in mRNA, with its critical role in gene expression regulation and cell fate determination increasingly recognized in recent research. The immune system, essential for defense against infections and maintaining internal stability through interactions with other bodily systems, is significantly influenced by m6A modification. This modification acts as a key post-transcriptional regulator of immune responses, though its effects on different immune cells vary across diseases. This review delineates the impact of m6A modification across major system-related cancers-including those of the respiratory, digestive, endocrine, nervous, urinary reproductive, musculoskeletal system malignancies, as well as acute myeloid leukemia and autoimmune diseases. We explore the pathogenic roles of m6A RNA modifications within the tumor immune microenvironment and the broader immune system, highlighting how RNA modification regulators interact with immune pathways during disease progression. Furthermore, we discuss how the expression patterns of these regulators can influence disease susceptibility to immunotherapy, facilitating the development of diagnostic and prognostic models and pioneering new therapeutic approaches. Overall, this review emphasizes the challenges and prospective directions of m6A-related immune regulation in various systemic diseases throughout the body.

Examining the evidence for mutual modulation between m6A modification and circular RNAs: current knowledge and future prospects

The resistance of cancer cells to treatment significantly impedes the success of therapy, leading to the recurrence of various types of cancers. Understanding the specific mechanisms of therapy resistance may offer novel approaches for alleviating drug resistance in cancer. Recent research has shown a reciprocal relationship between circular RNAs (circRNAs) and N6-methyladenosine (m6A) modification, and their interaction can affect the resistance and sensitivity of cancer therapy. This review aims to summarize the latest developments in the m6A modification of circRNAs and their importance in regulating therapy resistance in cancer. Furthermore, we explore their mutual interaction and exact mechanisms and provide insights into potential future approaches for reversing cancer resistance.

METTL5 promotes cell proliferation, invasion, and migration by up-regulating Toll-like receptor 8 expression in colorectal cancer

BACKGROUND

N6-methyladenosine (m6A) modification represents the predominant alteration found in eukaryotic messenger RNA and plays a crucial role in the progression of various tumors. However, despite its significance, the comprehensive investigation of METTL5, a key m6A methyltransferase, in colorectal cancer (CRC) remains limited.

AIM

To investigate the role of METTL5 in CRC.

METHODS

We assessed METTL5 expression levels in clinical samples obtained from CRC patients as well as in CRC cell lines. To elucidate the downstream targets of METTL5, we performed RNA-sequencing analysis coupled with correlation analysis, leading us to identify Toll-like receptor 8 (TLR8) as a potential downstream target. In vitro functional assessments of METTL5 and TLR8 were conducted using CCK-8 assays, scratch assays, as well as assays measuring cell migration and invasion.

RESULTS

Our findings reveal a pronounced upregulation of METTL5 expression in both CRC cells and tissues, which correlated significantly with an unfavorable prognosis. In vitro experiments unequivocally demonstrated the oncogenic role of METTL5, as evidenced by its promotion of CRC cell proliferation, invasion, and migration. Notably, we identified TLR8 as a downstream target of METTL5, and subsequent down-regulation of TLR8 led to a significant inhibition of CRC cell proliferation, invasion, and tumor growth.

CONCLUSION

The heightened expression of METTL5 in CRC is strongly associated with clinicopathological features and a poor prognosis, thereby underscoring its potential utility as a critical marker for facilitating early diagnosis and prognostication in CRC.

Recent advances of m6A methylation in skeletal system disease

Skeletal system disease (SSD) is defined as a class of chronic disorders of skeletal system with poor prognosis and causes heavy economic burden. m6A, methylation at the N6 position of adenosine in RNA, is a reversible and dynamic modification in posttranscriptional mRNA. Evidences suggest that m6A modifications play a crucial role in regulating biological processes of all kinds of diseases, such as malignancy. Recently studies have revealed that as the most abundant epigentic modification, m6A is involved in the progression of SSD. However, the function of m6A modification in SSD is not fully illustrated. Therefore, make clear the relationship between m6A modification and SSD pathogenesis might provide novel sights for prevention and targeted treatment of SSD. This article will summarize the recent advances of m6A regulation in the biological processes of SSD, including osteoporosis, osteosarcoma, rheumatoid arthritis and osteoarthritis, and discuss the potential clinical value, research challenge and future prospect of m6A modification in SSD.