Modulation of m6A RNA modification by DAP3 in cancer cells.

N6-methyladenosine (m6A) RNA methylation is a prevalent RNA modification that significantly impacts RNA metabolism and cancer development. Maintaining the global m6A levels in cancer cells relies on RNA accessibility to methyltransferases and the availability of the methyl donor S-adenosylmethionine (SAM). Here, we reveal that death associated protein 3 (DAP3) plays a crucial role in preserving m6A levels through two distinct mechanisms. First, although DAP3 is not a component of the m6A writer complex, it directly binds to m6A target regions, thereby facilitating METTL3 binding. Second, DAP3 promotes MAT2A's last intron splicing, increasing MAT2A protein, cellular SAM, and m6A levels. Silencing DAP3 hinders tumorigenesis, which can be rescued by MAT2A overexpression. This evidence suggests DAP3's role in tumorigenesis, partly through m6A regulation. Our findings unveil DAP3's complex role as an RNA-binding protein and tumor promoter, impacting RNA processing, splicing, and m6A modification in cancer transcriptomes.

New insights into the dynamics of m6A epitranscriptome: hybrid-seq identifies novel mRNAs of the m6A writers METTL3/14.

Background: N6-methyladenosine (m6A), a prevalent mRNA modification, is dynamically regulated by methyltransferases, including METTL3 and METTL14.Materials & methods: In the current study, we employed a custom hybrid-seq method to identify novel METTL3/14 transcripts, explore their protein-coding capacities and predict the putative role of the METTL isoforms.Results: Demultiplexing of the hybrid-seq barcoded datasets unraveled the expression patterns of the newly identified mRNAs in major malignancies as well as in non-malignant cells, providing a deeper understanding of the methylation pathways. Open reading frame query revealed novel METTL3/14 isoforms, broadening our perspective for the structural diversity within METTL family.Conclusion: Our findings offer significant insights into the intricate transcriptional landscape of METTL3/14, shedding light on the regulatory mechanisms underlying methylation in mRNAs.

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The m6A writer KIAA1429 regulates photoaging progression via MFAP4-dependent collagen synthesis.

BACKGROUND: N6-Methyladenosine (m6A) methylation, a common form of RNA modification, play an important role in the pathogenesis of various diseases and in the ontogeny of organisms. Nevertheless, the precise function of m6A methylation in photoaging remains unknown. OBJECTIVES: This study aims to investigate the biological role and underlying mechanism of m6A methylation in photoaging. METHODS: m6A dot blot, Real-time quantitative PCR (RT-qPCR), western blot and immunohistochemical (IHC) assays were employed to detect the m6A level and specific m6A methylase in ultraviolet ray (UVR)-induced photoaging tissue. The profile of m6A-tagged mRNA was identified by methylated RNA immunoprecipitation sequencing (MeRIP-seq) and RNA-seq analysis. Finally, we investigated the regulatory mechanism of KIAA1429 by MeRIP-qPCR, RNA knockdown and immunofluorescence assay. RESULTS: m6A levels were increased in photoaging and were closely associated with the upregulation of KIAA1429 expression. 1331 differentially m6A methylated genes were identified in the UVR group compared with the control group, of which 1192 (90%) were hypermethylated. Gene ontology analysis showed that genes with m6A hypermethylation and mRNA downregulation were mainly involved in extracellular matrix metabolism and collagen metabolism-related processes. Furthermore, KIAA1429 knockdown abolished the downregulation of TGF-bRII and upregulation of MMP1 in UVR-irradiated human dermal fibroblasts (HDFs). Mechanically, we identified MFAP4 as a target of KIAA1429-mediated m6A modification and KIAA1429 might suppress collagen synthesis through an m6A-MFAP4-mediated process. CONCLUSIONS: The increased expression of KIAA1429 hinders collagen synthesis during UVR-induced photoaging, suggesting that KIAA1429 represents a potential candidate for targeted therapy to mitigate UVR-driven photoaging.

NOVA2 regulates the properties of liver cancer stem cells and lenvatinib resistance in hepatocellular carcinoma via the Wnt pathway.

Background: The regulation of cancer stem cells (CSCs) is influenced by RNA-binding proteins (RBPs). The present study sought to investigate the role of NOVA2 in the processes of self-renewal, carcinogenesis, and lenvatinib resistance in liver CSCs. Methods: Neuro-oncological ventral antigen 2 (NOVA2) expression in liver CSCs was examined by real-time polymerase chain reaction (PCR). In vitro experiments were used to assess the effects of NOVA2 on liver CSC expansion and lenvatinib resistance. Results: In our study, the expression of the RBP NOVA2 was higher in CSCs. NOVA2 also increased the capacity for self-renewal and carcinogenesis of the liver CSCs via the Wnt pathway. Further, suppressing the Wnt pathway leads to desensitization of the hepatocellular carcinoma (HCC) cells that overexpress NOVA2 to apoptosis caused by lenvatinib. Analyzing patient data confirmed reduced levels of NOVA2 and therefore we speculate that NOVA2 may serve as a potential indicator for response to lenvatinib in patients with HCC. Methyltransferase-like 3 (METTL3) and YTH N6-methyladenosine RNA-binding protein 1 (YTHDF1)-dependent N6-methyladenosine (m6A) methylation were linked to upregulation of NOVA2 in HCC. Furthermore, it was shown that the expression of METTL3 was elevated in cellular models of type 2 diabetes mellitus (T2DM). Conclusions: NOVA2 is involved in the process of liver CSC self-renewal and carcinogenesis. In addition, NOVA2 expression may help identify patients with a higher chance of benefiting from lenvatinib treatment and can be a promising therapeutic target for HCC.

Interaction of the intestinal cytokines-JAKs-STAT3 and 5 axes with RNA N6-methyladenosine to promote chronic inflammation-induced colorectal cancer.

Colorectal cancer (CRC) is one of the most common cancers, with a high mortality rate worldwide. Mounting evidence indicates that mRNA modifications are crucial in RNA metabolism, transcription, processing, splicing, degradation, and translation. Studies show that N6-methyladenosine (m6A) is mammalians' most common epi-transcriptomic modification. It has been demonstrated that m6A is involved in cancer formation, progression, invasion, and metastasis, suggesting it could be a potential biomarker for CRC diagnosis and developing therapeutics. Cytokines, growth factors, and hormones function in JAK/STAT3/5 signaling pathway, and they could regulate the intestinal response to infection, inflammation, and tumorigenesis. Reports show that the JAK/STAT3/5 pathway is involved in CRC development. However, the underlying mechanism is still unclear. Signal Transducer and Activator of Transcription 3/5 (STAT3, STAT5) can act as oncogenes or tumor suppressors in the context of tissue types. Also, epigenetic modifications and mutations could alter the balance between pro-oncogenic and tumor suppressor activities of the STAT3/5 signaling pathway. Thus, exploring the interaction of cytokines-JAKs-STAT3 and/or STAT5 with mRNA m6A is of great interest. This review provides a comprehensive overview of the characteristics and functions of m6A and JAKs-STAT3/5 and their relationship with gastrointestinal (GI) cancers.

Insights into the m6A demethylases FTO and ALKBH5 : structural, biological function, and inhibitor development.

N6-methyladenosine (m6A) is dynamically regulated by methyltransferases (termed "writers") and demethylases (referred to as "erasers"), facilitating a reversible modulation. Changes in m6A levels significantly influence cellular functions, such as RNA export from the nucleus, mRNA metabolism, protein synthesis, and RNA splicing. They are intricately associated with a spectrum of pathologies. Moreover, dysregulation of m6A modulation has emerged as a promising therapeutic target across many diseases. m6A plays a pivotal role in controlling vital downstream molecules and critical biological pathways, contributing to the pathogenesis and evolution of numerous conditions. This review provides an overview of m6A demethylases, explicitly detailing the structural and functional characteristics of FTO and ALKBH5. Additionally, we explore their distinct involvement in various diseases, examine factors regulating their expression, and discuss the progress in inhibitor development.

METTL5 enhances the mRNA stability of TPRKB through m6A modification to facilitate the aggressive phenotypes of hepatocellular carcinoma cell.

N6-methyladenosine (m6A) modification plays an important role in RNA molecular functions, therefore affecting the initiation and development of hepatocellular carcinoma (HCC). Herein, multiple datasets were applied to conduct a comprehensive analysis of DEGs within HCC and the analysis revealed significant dysregulation of numerous genes. Functional and signaling pathway enrichment analyses were performed. Further, TP53RK binding protein (TPRKB) emerged as a significant factor, exhibiting high expression level within HCC tissue samples and cells which could predict HCC patients' poor OS. Knockdown investigations of TPRKB in vitro demonstrated the effect of TPRKB knockdown on attenuating the aggressiveness of HCC cells by suppressing the viability, colony formation, invasive ability, and migratory ability, inducing cell cycle arrest, and facilitating the apoptosis of HCC cells. Investigations in vivo revealed that TPRKB knockdown significantly suppressed tumor growth in mice model. Additionally, the study identified methyltransferase 5, N6-adenosine (METTL5) as a potential regulator of TPRKB expression via m6A modification, positively regulating TPRKB expression by enhancing TPRKB mRNA stability. The dynamic effects of METTL5 and TPRKB upon the phenotypes of HCC cells further confirmed that TPRKB overexpression partially abolished the anti-cancer effects of METTL5 knockdown upon the aggressiveness of HCC cells. Conclusively, our findings uncover that TPRKB, significantly overexpressed in HCC, exerts a critical effect on promoting tumor aggressiveness, and its expression shows to be positively regulated by METTL5 via m6A methylation. These insights deepen the understanding of HCC pathogenesis and open new avenues for targeted therapies, highlighting that METTL5-TPRKB axis is an underlying new therapeutic target in HCC management.

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.

FTO promotes the progression of bladder cancer via demethylating m6A modifications in PTPN6 mRNA.

Bladder cancer (BC), a highly prevalent malignancy of the urinary system, necessitates further investigation into its progression mechanisms. N6-methyladenosine (m6A) RNA methylation, a prevalent modification in cellular RNA, has been implicated in the tumorigenesis and metastasis of various cancers. In this study, the upregulation of FTO in human BC samples and its association with poor prognosis were demonstrated using immunohistochemistry (IHC) on tissue sections collected from BC patients. The functional role of FTO in promoting the proliferation and metastasis abilities of BC cells was determined using a combination of in vitro and in vivo assays. In vitro, we conducted cell proliferation assays, such as the Cell Counting Kit-8 (CCK-8) assay, and metastasis assays, including the wound healing assay and transwell invasion assay. In vivo, we employed xenograft models to assess tumor growth and metastasis. Furthermore, our investigation into potential FTO targets in BC cells revealed that FTO modifies PTPN6 mRNA, leading to increased stability and expression of PTPN6, thereby enhancing proliferation and metastasis abilities. In conclusion, our findings indicate that FTO serves as an oncogenic factor in BC, suggesting its potential utility as a diagnostic or prognostic biomarker for bladder cancer.

Identification of key genes with abnormal RNA methylation modification and selected m6A regulators in ankylosing spondylitis.

BACKGROUND: N6-methyladenosine (m6A) has been identified as the most abundant modification of RNA molecules and the aberrant m6A modifications have been associated with the development of autoimmune diseases. However, the role of m6A modification in ankylosing spondylitis (AS) has not been adequately investigated. Therefore, we aimed to explore the significance of m6A regulator-mediated RNA methylation in AS. METHODS: The methylated RNA immunoprecipitation sequencing (meRIP-seq) and digital RNA sequencing (Digital RNA-seq) were conducted using the peripheral blood mononuclear cells from three AS cases and three healthy controls, to identify genes affected by abnormal RNA methylation. The genes associated with different peaks were cross-referenced with AS-related genes obtained from the GeneCards Suite. Subsequently, the expression levels of shared differentially expressed genes (DEGs) and key m6A regulators in AS were evaluated using data from 68 AS cases and 36 healthy controls from two data sets (GSE25101 and GSE73754). In addition, the results were validated through quantitative polymerase chain reaction (qPCR). RESULTS: The meRIP-seq and Digital RNA-seq analyses identified 28 genes with upregulated m6A peaks but with downregulated expression, and 52 genes with downregulated m6A peaks but with upregulated expression. By intersecting the genes associated with different peaks with 2184 AS-related genes from the GeneCards Suite, we identified a total of five shared DEGs: BCL11B, KAT6B, IL1R1, TRIB1, and ALDH2. Through analysis of the data sets and qPCR, we found that BCL11B and IL1R1 were differentially expressed in AS. Moreover, two key m6A regulators, WTAP and heterogeneous nuclear ribonucleoprotein C, were identified. CONCLUSIONS: In conclusion, the current study revealed that m6A modification plays a crucial role in AS and might hence provide a new treatment strategy for AS disease.

M6a Methylation: A New Avenue for Control of the Development of Type 2 Diabetes Mellitus and its Complications.

The rapidly emerging prevalence of type 2 diabetes mellitus (T2DM) and its associated complications have formed an increasingly serious threat to human life and health. Therefore, there is an urgent requirement to investigate the pathogenesis of T2DM and its complications, which will be conducive to discovering effective drugs for prevention and treatment. N6-methyladenosine (m6A) methylation is the most abundant and prevalent epigenetic modification of mRNA in mammals. m6A methylation is a dynamically reversible epigenetic transcriptome modification process that is jointly regulated by methyltransferases, demethylases and methylated reading proteins, which control the fate of target mRNAs through influencing splicing, translation and decay. Recent studies have revealed that m6A methylation plays an important role in ß cellular function, insulin sensitivity and glycolipid metabolism. In this review, we summarized the current roles of m6A methylation in T2DM and T2DM-related complications such as diabetes nephropathy (DN), diabetes cardiovascular disease (DCD) and diabetes retinopathy (DR). Additionally, we sought the potential mechanism of m6A in T2DM and related complications, which may provide a rationale and strategy for potential therapeutic targeting of T2DM and its complications.

Detection, distribution, and functions of RNA N 6-methyladenosine (m6A) in plant development and environmental signal responses.

The epitranscriptomic mark N 6-methyladenosine (m6A) is the most common type of messenger RNA (mRNA) post-transcriptional modification in eukaryotes. With the discovery of the demethylase FTO (FAT MASS AND OBESITY-ASSOCIATED PROTEIN) in Homo Sapiens, this modification has been proven to be dynamically reversible. With technological advances, research on m6A modification in plants also rapidly developed. m6A modification is widely distributed in plants, which is usually enriched near the stop codons and 3'-UTRs, and has conserved modification sequences. The related proteins of m6A modification mainly consist of three components: methyltransferases (writers), demethylases (erasers), and reading proteins (readers). m6A modification mainly regulates the growth and development of plants by modulating the RNA metabolic processes and playing an important role in their responses to environmental signals. In this review, we briefly outline the development of m6A modification detection techniques; comparatively analyze the distribution characteristics of m6A in plants; summarize the methyltransferases, demethylases, and binding proteins related to m6A; elaborate on how m6A modification functions in plant growth, development, and response to environmental signals; and provide a summary and outlook on the research of m6A in plants.

UBE2D3 regulated by WTAP-mediated m6A modification inhibits temozolomide chemosensitivity in glioblastoma.

To explore how the ubiquitin-conjugating enzyme E2D3 (UBE2D3) influences temozolomide (TMZ) resistance in glioblastoma (GBM), and to clarify the association between UBE2D3 and WTAP. The UBE2D3 protein expression in GBM tissues were detected using immunohistochemistry (IHC) through tissue microarrays. The potential pathways of UBE2D3 in TCGA-GBM were predicted via Gene Set Enrichment Analysis (GSEA). To investigate UBE2D3's role in TMZ resistance, GBM cells were transduced with UBE2D3 shRNA or overexpression lentivirus, followed by assessments of CCK-8, flow cytometry, comet assay, and western blot analysis. Furthermore, a subcutaneous tumor model was established in nude mice using U87 cells transduced with interfering lentivirus to observe tumor growth and assess cell apoptosis using TUNEL staining. Mechanically, m6A content analysis, m6A methylated RNA immunoprecipitation quantitative PCR, reporter gene assay, mRNA stability measurements, RNA immunoprecipitation, quantitative Real-Time PCR, and Western blot assays were carried out to verify the role of WTAP/IGF2BP1 in regulating UBE2D3 expression. UBE2D3 exhibited elevated expression levels in GBM tissues compared with normal brain tissues and was associated with the DNA repair signaling pathway. In both in vitro and in vivo studies, it was demonstrated that TMZ treatment combined with reduced UBE2D3 expression further suppressed U87 cell viability and tumor growth, with a notable increase in apoptosis rate and DNA damage. Conversely, the overexpression of UBE2D3 had the opposite impact. Furthermore, our findings revealed that WTAP promotes the m6A modification of UBE2D3 via an IGF2BP1-dependent mechanism. The WTAP-IGF2BP1 axis regulates UBE2D3 stability in an m6A-dependent manner, influencing tumor malignancy and TMZ chemosensitivity in GBM via the DNA repair signaling pathway.

Comprehensive landscape of m6A regulator-related gene patterns and tumor microenvironment infiltration characterization in gastric cancer.

The epigenetic regulation of N6-methyladenosine (m6A) has attracted considerable interest in tumor research, but the potential roles of m6A regulator-related genes, remain largely unknown within the context of gastric cancer (GC) and tumor microenvironment (TME). Here, a comprehensive strategy of data mining and computational biology utilizing multiple datasets based on 28 m6A regulators (including novel anti-readers) was employed to identify m6A regulator-related genes and patterns and elucidate their underlying mechanisms in GC. Subsequently, a scoring system was constructed to evaluate individual prognosis and immunotherapy response. Three distinct m6A regulator-related patterns were identified through the unsupervised clustering of 56 m6A regulator-related genes (all significantly associated with GC prognosis). TME characterization revealed that these patterns highly corresponded to immune-inflamed, immune-excluded, and immune-desert phenotypes, and their TME characteristics were highly consistent with different clinical outcomes and biological processes. Additionally, an m6A-related scoring system was developed to quantify the m6A modification pattern of individual samples. Low scores indicated high survival rates and high levels of immune activation, whereas high scores indicated stromal activation and tumor malignancy. Furthermore, the m6A-related scores were correlated with tumor mutation loads and various clinical traits, including molecular or histological subtypes and clinical stage or grade, and the score had predictive values across all digestive system tumors and even in all tumor types. Notably, a low score was linked to improved responses to anti-PD-1/L1 and anti-CTLA4 immunotherapy in three independent cohorts. This study has expanded the important role of m6A regulator-related genes in shaping TME diversity and clinical/biological traits of GC. The developed scoring system could help develop more effective immunotherapy strategies and personalized treatment guidance.

Role of M6a Methylation in Myocardial Ischemia-Reperfusion Injury and Doxorubicin-Induced Cardiotoxicity.

Cardiovascular disease remains the leading cause of death worldwide, with acute myocardial infarction and anticancer drug-induced cardiotoxicity being the significant factors. The most effective treatment for acute myocardial infarction is rapid restoration of coronary blood flow by thrombolytic therapy or percutaneous coronary intervention. However, myocardial ischemia-reperfusion injury (MI/RI) after reperfusion therapy is common in acute myocardial infarction, thus affecting the prognosis of patients with acute myocardial infarction. There is no effective treatment for MI/RI. Anthracyclines such as Doxorubicin (DOX) have limited clinical use due to their cardiotoxicity, and the mechanism of DOX-induced cardiac injury is complex and not yet fully understood. N6-methyladenosine (m6A) plays a crucial role in many biological processes. Emerging evidence suggests that m6A methylation plays a critical regulatory role in MI/RI and DOX-induced cardiotoxicity (DIC), suggesting that m6A may serve as a novel biomarker and therapeutic target for MI/RI and DIC. M6A methylation may mediate the pathophysiological processes of MI/RI and DIC by regulating cellular autophagy, apoptosis, oxidative stress, and inflammatory response. In this paper, we first focus on the relationship between m6A methylation and MI/RI, then further elucidate that m6A methylation may mediate the pathophysiological process of MI/RI through the regulation of cellular autophagy, apoptosis, oxidative stress, and inflammatory response. Finally, briefly outline the roles played by m6A in DIC, which will provide a new methodology and direction for the research and treatment of MI/RI and DIC.

METTL3 shapes m6A epitranscriptomic landscape for successful human placentation.

Methyltransferase-like 3 (METTL3), the catalytic enzyme of methyltransferase complex for m6A methylation of RNA, is essential for mammalian development. However, the importance of METTL3 in human placentation remains largely unexplored. Here, we show that a fine balance of METTL3 function in trophoblast cells is essential for successful human placentation. Both loss-of and gain-in METTL3 functions are associated with adverse human pregnancies. A subset of recurrent pregnancy losses and preterm pregnancies are often associated with loss of METTL3 expression in trophoblast progenitors. In contrast, METTL3 is induced in pregnancies associated with fetal growth restriction (FGR). Our loss of function analyses showed that METTL3 is essential for the maintenance of human TSC self-renewal and their differentiation to extravillous trophoblast cells (EVTs). In contrast, loss of METTL3 in human TSCs promotes syncytiotrophoblast (STB) development. Global analyses of RNA m6A modification and METTL3-RNA interaction in human TSCs showed that METTL3 regulates m6A modifications on the mRNA molecules of critical trophoblast regulators, including GATA2, GATA3, TEAD1, TEAD4, WWTR1, YAP1, TFAP2C and ASCL2, and loss of METTL3 leads to depletion of mRNA molecules of these critical regulators. Importantly, conditional deletion of Mettl3 in trophoblast progenitors of an early post-implantation mouse embryo also leads to arrested self-renewal. Hence, our findings indicate that METLL3 is a conserved epitranscriptomic governor in trophoblast progenitors and ensures successful placentation by regulating their self-renewal and dictating their differentiation fate.

m6A-dependent mature miR-151-5p accelerates the malignant process of HNSCC by targeting LYPD3.

miRNA has emerged as a crucial regulator in various of pathological and physiological processes, yet its precise mechanism of action the detailed mechanism of their action in Head and neck squamous cell carcinoma (HNSCC) remains incompletely understood. This study sheds light on the role of mi-151-5p, revealing its significantly elevated expression in tumor cells, which notably enhances the invasion and migration of HNSCC cells. This effect is achieved through directly targeting LY6/PLAUR Domain Containing 3 (LYPD3) by miR-151-5p, involving complementary binding to the 3'-untranslated regions (3'-UTR) in the mRNA of LYPD3. Consequently, this interaction accelerates the metastasis of HNSCC. Notably, clinical observations indicate a correlation between high expression of miR-151-5p and low levels of LYPD3 in clinical settings are correlated with poor prognosis of HNSCC patients. Furthermore, our investigation demonstrates that glycosylation of LYPD3 modulates its subcellular localization and reinforces its role in suppressing HNSCC metastasis. Additionally, we uncover a potential regulatory mechanism involving the facilitation of miR-151-5p maturation and accumulation through N6-methyladenosine (m6A) modification. This process is orchestrated by methyltransferase-like 3 (METTL3) and mediated by a newly identified reader, heterogeneous nuclear ribonucleoprotein U (hnRNP U). These findings collectively underscore the significance of the METTL3/miR-151-5p/LYPD3 axis serves as a prominent driver in the malignant progression of HNSCC.

METTL3 regulates thyroid cancer differentiation and chemosensitivity by modulating PAX8.

Background: Thyroid cancer (TC) is a common endocrine cancer with a favourable prognosis. However, poor patient prognosis due to TC dedifferentiation is becoming an urgent challenge. Recently, methyltransferase-like 3 (METTL3)-mediated N6 -methyladenosine (m6A) modification has been demonstrated to play an important role in the occurrence and progression of various cancers and a tumour suppressor role in TC. However, the mechanism of METTL3 in TC remains unclear. Methods: The correlation between METTL3 and prognosis in TC patients was evaluated by immunohistochemistry. Mettl3fl/flBrafV600ETPO-cre TC mouse models and RNA-seq were used to investigate the underlying molecular mechanism, which was further validated by in vitro experiments. The target gene of METTL3 was identified, and the complete m6A modification process was described. The phenomenon of low expression of METTL3 in TC was explained by identifying miRNAs that regulate METTL3. Results: We observed that METTL3 expression was negatively associated with tumour progression and poor prognosis in TC. Mechanistically, silencing METTL3 promoted the progression and dedifferentiation of papillary thyroid carcinoma (PTC) both in vivo and in vitro. Moreover, overexpressing METTL3 promoted the sensitivity of PTC and anaplastic thyroid cancer (ATC) cells to chemotherapeutic drugs and iodine-131 (131I) administration. Overall, the METTL3/PAX8/YTHDC1 axis has been revealed to play a pivotal role in repressing tumour occurrence, and is antagonized by miR-493-5p.

Targeting FTO suppresses hepatocellular carcinoma by inhibiting ERBB3 and TUBB4A expression.

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

RBM15 facilities lung adenocarcinoma cell progression by regulating RASSF8 stability through N6 Methyladenosine modification.

Invasion and migration are the primary factors for mortality in lung adenocarcinoma (LUAD) patients. The precise role of RNA-binding motif protein15 (RBM15)-mediated m6A modification in LUAD is not yet fully clarified. This research aims to elucidate the mechanism of RBM15 in the invasion and migration of LUAD. Western blot and dot blot assay results showed that RBM15 and methylation levels of m6A were highly expressed in LUAD tissues. Overexpression of RBM15 by lentivirus transfection increased m6A levels and promoted the invasion, migration, and proliferation of A549 and H1734 cells. Knockdown of RBM15 by lentivirus transfection had opposite effects on m6A levels, invasion, migration, and proliferation of A549 and H1734 cells. The results of nude mouse proliferation models confirmed that RBM15 knockdown inhibited in vivo tumor proliferation . Sequencing and immunoprecipitation identified RASSF8 as an interacting protein of RBM15 involved in cell invasion and migration. RBM15-mediated m6A modification inhibited RASSF8 protein levels and increased LUAD cell invasion and migration. The rescue assays demonstrated that the regulation of RBM15 on LUAD cell invasion and migration was partially rescued by RASSF8. In conclusion, RBM15-mediated m6A modification inhibits the RASSF8 protein levels and increases cell invasion and migration. Thus, targeting the RBM15-m6A-RASSF8 axis may be a promising strategy for repressing LUAD cell invasion and migration.