Propofol attenuates prostate cancer progression by upregulating TRHDE-AS1 expression, and METTL14 could mediate its m6A modification.

Propofol has become a microtubule-stabilizing drug for prostate cancer (PC) therapy, but propofol resistance impairs the therapeutic effect. This study aimed to explore the regulatory mechanism of propofol in the pathogenesis of PC through mechanisms involving N6-methyladenosine (m6A) modification. The changes in PC cell malignancy were evaluated by means of transwell, cell counting kit 8 (CCK-8), western blotting and tumour xenograft model assays. Long noncoding RNA TRHDE-AS1 and m6A methyltransferase METTL14 expression levels were determined via reverse transcription quantitative polymerase chain reaction (RT-qPCR). The m6A modification of TRHDE-AS1 which was mediated by METTL14 was confirmed by conducting methylated RNA immunoprecipitation (MeRIP) assay. We observed that propofol (200 µM) inhibited PC cell malignancy in vivo and in vitro, elucidating that it impaired cell proliferation, migration and tumour growth but induced apoptosis. TRHDE-AS1 expression was observed to be lower in PC cells and tissues, and propofol induced TRHDE-AS1 upregulation in PC cells. Propofol was capable of reversing the tumour-promoting effect of TRHDE-AS1 knockdown in PC cells. Additionally, METTL14 was upstream of TRHDE-AS1 to induce m6A modification of TRHDE-AS1 in PC cells. Collectively, our results show that propofol prevents PC progression by upregulating TRHDE-AS1 expression and METTL14 is involved in the m6A modification of TRHDE-AS1. These findings suggest that TRHDE-AS1 may be a potential therapeutic target for the improvement of propofol's therapeutic effect.

ZNF740 facilitates the malignant progression of hepatocellular carcinoma via the METTL3/HIF­1A signaling axis.

Hepatocellular carcinoma (HCC) is the second leading cause of cancer­related death, and efficient treatments to facilitate recovery and enhance long­term outcomes are lacking. Zinc finger proteins (ZNFs), known as the largest group of transcription factors, have gained interest for their roles in HCC by stimulating the transcription of well­known tumor­causing genes. However, the specific roles and molecular mechanisms of ZNF740 in HCC remain unknown. The present study performed bioinformatics analysis and RNA­sequencing analysis of differentially expressed genes in HCC, detected ZNF740 expression levels in HCC using reverse transcription­quantitative PCR, western blotting and immunohistochemistry, and explored the effects of ZNF740 on the progression of liver cancer in vitro and in vivo using cellular functionality assays and cell­derived xenografts. In addition, a dual­luciferase reporter assay was performed to analyze the binding of ZNF740 with the METTL3 promoter. Furthermore, cell functionality experiments were performed to analyze whether ZNF740 promotes the proliferation of liver cancer cells in a METTL3­dependent manner. Bioinformatics and immunoprecipitation assays were further used to analyze the molecular mechanism of ZNF740 in liver cancer. The present study demonstrated that ZNF740 expression was upregulated in HCC. Mechanistically, overexpressed ZNF740 interacted with the methyltransferase­like 3 (METTL3) promoter and increased METTL3 expression, leading to the stabilization of hypoxia­inducible factor­1A (HIF1A) mRNA in an N6­methyladenosine/YTH N6­methyladenosine RNA­binding protein 1­dependent manner. Eventually, the ZNF740/METTL3/HIF1A signaling axis may facilitate the proliferation, invasion and metastasis of liver cancer via METTL3/HIF­1A signaling. The present findings revealed the important role of ZNF740 and suggested a potential therapeutic approach that might improve clinical therapies for liver cancer.

Targeting METTL3 enhances the chemosensitivity of non-small cell lung cancer cells by decreasing ABCC2 expression in an m6A-YTHDF1-dependent manner.

Patients with non-small cell lung cancer (NSCLC) are easily resistant to first-line chemotherapy with paclitaxel (PTX) or carboplatin (CBP). N6-methyladenosine (m6A) methyltransferase-like 3 (METTL3) has crucial functions in m6A modification and tumorigenesis. However, its role in chemoresistance of NSCLC is still elusive. Here, we demonstrated that METTL3 inhibitor STM2457 significantly reduced the IC50 values of PTX or CBP in NSCLC cells, and they showed a synergistic effect. Comparing with monotherapy, a combination of STM2457 and PTX or CBP exhibited more potent in vitro and in vivo anti-tumor efficacy. In addition, we found that ATP binding cassette subfamily C member 2 (ABCC2) was responsively elevated in cytomembrane after PTX or CBP treatment, and targeting METTL3 could reverse this effect. Mechanistically, targeting METTL3 decreased the m6A modification of ABCC2 mRNA and accelerated its mRNA degradation. Further studies revealed that YTHDF1 could bind and stabilize the m6A-modified mRNA of ABCC2, while YTHDF1 knockdown promoted it mRNA degradation. These results, taken together, demonstrate that targeting METTL3 enhances the sensitivity of NSCLC cells to PTX or CBP by decreasing the cytomembrane-localized ABCC2 in an m6A-YTHDF1-dependent manner, and suggest that METTL3 may be a potential therapeutic target for acquired resistance to PTX or CBP in NSCLC.

METTL3-mediated m6A modification of OTUD1 aggravates press overload induced myocardial hypertrophy by deubiquitinating PGAM5.

Background: Pathological cardiac hypertrophy, a condition that contributes to heart failure, is characterized by its intricate pathogenesis. The meticulous regulation of protein function, localization, and degradation is a crucial role played by deubiquitinating enzymes in cardiac pathophysiology. This study clarifies the participation and molecular mechanism of OTUD1 (OTU Deubiquitinase 1) in pathological cardiac hypertrophy. Methods: We generated a cardiac-specific Otud1 knockout mouse line (Otud1-CKO) and adeno-associated virus serotype 9-Otud1 mice to determine the role of Otud1 in cardiac hypertrophy. Its impact on cardiomyocytes enlargement was investigated using the adenovirus. RNA immunoprecipitation was used to validate the specific m6a methyltransferase interacted with OTUD1 transcript. RNA sequencing in conjunction with immunoprecipitation-mass spectrometry analysis was employed to identify the direct targets of OTUD1. A series of depletion mutant plasmids were constructed to detect the interaction domain of OTUD1 and its targets. Results: Ang II-stimulated neonatal rat cardiac myocytes and mice hearts subjected to transverse aortic constriction (TAC) showed increased protein levels of Otud1. Cardiac hypertrophy and dysfunction were less frequent in Otud1-CKO mice during TAC treatment, while Otud1 overexpression worsened cardiac hypertrophy and remodeling. METTL3 mediated m6A modification of OTUD1 transcript promoted mRNA stability and elevated protein expression. In terms of pathogenesis, Otud1 plays a crucial role in cardiac hypertrophy by targeting Pgam5, leading to the robust activation of the Ask1-p38/JNK signal pathway to accelerate cardiac hypertrophy. Significantly, the pro-hypertrophy effects of Otud1 overexpression were largely eliminated when Ask1 knockdown. Conclusion: Our findings confirm that targeting the OTUD1-PGAM5 axis holds significant potential as a therapeutic approach for heart failure associated with pathological hypertrophy.

METTL18 functions as a Phenotypic Regulator in Src-Dependent Oncogenic Responses of HER2-Negative Breast Cancer.

Methyltransferase-like (METTL)18 has histidine methyltransferase activity on the RPL3 protein and is involved in ribosome biosynthesis and translation elongations. Several studies have reported that actin polymerization serves as a Src regulator, and HSP90 is involved in forming polymerized actin bundles. To understand the role of METTL18 in breast cancer and to demonstrate the importance of METTL18 in HER-2 negative breast cancer metastasis, we used biochemical, molecular biological, and immunological approaches in vitro (breast tumor cell lines), in vivo (tumor xenograft model), and in samples of human breast tumors. A gene expression comparison of 31 METTL series genes and 22 methyltransferases in breast cancer patients revealed that METTL18 is highly amplified in human HER2-negative breast cancer. In addition, elevated levels of METTL18 expression in patients with HER2-negative breast cancer are associated with poor prognosis. Loss of METTL18 significantly reduced the metastatic responses of breast tumor cells in vitro and in vivo. Mechanistically, METTL18 indirectly regulates the phosphorylation of the proto-oncogene tyrosine-protein kinase Src and its downstream molecules in MDA-MB-231 cells via METTL18-mediated RPL3 methylation, which is also involved in determining HSP90 integrity and protein levels. In confocal microscopy and F/G-actin assays, METTL18 was found to induce actin polymerization via HSP90. Molecular events involving METTL18, RPL3, HSP90, and actin polymerization yielded Src phosphorylated at both tyrosine 419 and tyrosine 530 with kinase activity and oncogenic functions. Therefore, it is suggested that the METTL18-HSP90-Actin-Src regulatory axis plays critical oncogenic roles in the metastatic responses of HER2-negative breast cancer and could be a promising therapeutic target.

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.

Biological Relevance of Dual Lysine and N-Terminal Methyltransferase METTL13.

The dual methyltransferase methyltransferase-like protein 13, also referred to as METTL13, or formerly known as FEAT (faintly expressed in healthy tissues, aberrantly overexpressed in tumors), has garnered attention as a significant enzyme in various cancer types, as evidenced by prior literature reviews. Recent studies have shed light on new potential roles for METTL13, hinting at its promise as a therapeutic target. This review aims to delve into the multifaceted biology of METTL13, elucidating its proposed mechanisms of action, regulatory pathways, and its implications in disease states, as supported by the current body of literature. Furthermore, the review will highlight emerging trends and gaps in our understanding of METTL13, paving the way for future research efforts. By contextualizing METTL13 within the broader landscape of cancer biology and therapeutics, this study serves as an introductory guide to METTL13, aiming to provide readers with a thorough understanding of its role in disease phenotypes.

Increased Motility in Campylobacter jejuni and Changes in Its Virulence, Fitness, and Morphology Following Protein Expression on Ribosomes with Altered RsmA Methylation.

Infection with Campylobacter jejuni is the major cause of human gastroenteritis in the United States and Europe, leading to debilitating autoimmune sequelae in many cases. While considerable progress has been made in detailing the infectious cycle of C. jejuni, a full understanding of the molecular mechanisms responsible for virulence remains to be elucidated. Here, we apply a novel approach by modulating protein expression on the pathogen's ribosomes by inactivating a highly conserved rRNA methyltransferase. Loss of the RsmA methyltransferase results in a more motile strain with greater adhesive and cell-invasive properties. These phenotypical effects correlate with enhanced expression of specific proteins related to flagellar formation and function, together with enzymes involved in cell wall/membrane and amino acid synthesis. Despite the enhancement of certain virulent traits, the null strain grows poorly on minimal media and is rapidly out-competed by the wild-type strain. Complementation with an active copy of the rsmA gene rescues most of the traits changed in the mutant. However, the complemented strain overexpresses rsmA and displays new flaws, including loss of the spiral cell shape, which is distinctive for C. jejuni. Proteins linked with altered virulence and morphology are identified here by mass spectrometry proteomic analyses of the strains.

N6-Methyladenosine Positively Regulates Coxsackievirus B3 Replication.

Enteroviruses such as coxsackievirus B3 are identified as a common cause of viral myocarditis, but the potential mechanism of its replication and pathogenesis are largely unknown. The genomes of a variety of viruses contain N6-methyladenosine (m6A), which plays important roles in virus replication. Here, by using the online bioinformatics tools SRAMP and indirect immunofluorescence assay (IFA), we predict that the CVB3 genome contains m6A sites and found that CVB3 infection could alter the expression and cellular localization of m6A-related proteins. Moreover, we found that 3-deazaadenosine (3-DAA), an m6A modification inhibitor, significantly decreased CVB3 replication. We also observed that the m6A methyltransferases methyltransferase-like protein 3 (METTL3) and METTL14 play positive roles in CVB3 replication, whereas m6A demethylases fat mass and obesity-associated protein (FTO) or AlkB homolog 5 (ALKBH5) have opposite effects. Knockdown of the m6A binding proteins YTH domain family protein 1 (YTHDF1), YTHDF2 and YTHDF3 strikingly decreased CVB3 replication. Finally, the m6A site mutation in the CVB3 genome decreased the replication of CVB3 compared with that in the CVB3 wild-type (WT) strain. Taken together, our results demonstrated that CVB3 could exploit m6A modification to promote viral replication, which provides new insights into the mechanism of the interaction between CVB3 and the host.

Systematic Identification and Characterization of O-Methyltransferase Gene Family Members Involved in Flavonoid Biosynthesis in Chrysanthemum indicum L.

Chrysanthemum indicum L. capitulum is an enriched source of flavonoids with broad-ranging biological activities, mainly due to their anti-inflammatory, anti-cancer, immune regulation, anti-microbial activity, hepatoprotective, and neuroprotective effects. The O-methylation of various secondary metabolites has previously been demonstrated to be mainly catalyzed by S-adenosyl-L-methionine-dependent O-methyltransferase (OMT) proteins encoded by the OMT gene family. However, limited comprehensive study was published on the OMT gene family, especially the CCoAOMT subfamily, involved in the O-methylation of flavonoids in Chrysanthemum. Here, we analyzed the spatiotemporal expression patterns of C. indicum OMT genes in leaf and flower at different developmental stages. Transcriptome sequencing and qRT-PCR analysis showed that COMTs were mainly highly expressed in capitulum, especially in full bloom, while CCoAOMTs were mainly highly expressed in leaves. Correlation analysis of OMT gene expression and flavonoids accumulation revealed that four OMTs (CHR00029120, CHR00029783, CHR00077404, and CHR00078333) were putatively involved in most methylated flavonoids biosynthesis in the capitulum. Furthermore, we identified a true CCoAOMT enzyme, CiCCoAOMT1, and found that it catalyzed O-methylation of quercetin and luteolin at the 3'-OH position. In summary, this work provides an important theoretical basis for further research on the biological functions of OMTs in C. indicum.

METTL16-SENP3-LTF axis confers ferroptosis resistance and facilitates tumorigenesis in hepatocellular carcinoma.

BACKGROUND: Ferroptosis, characterized by iron-dependent lipid peroxidation, emerges as a promising avenue for hepatocellular carcinoma (HCC) intervention due to its tumor susceptibility. RNA N6-methyladenosine (m6A) modification has been involved in several types of regulated cell death. However, the roles and molecular mechanisms of m6A-related regulators in HCC cell ferroptosis remain unclear. METHODS: By examining a series of m6A modification enzymes upon ferroptosis induction or inhibition, we identified METTL16 as a novel ferroptotic repressor in HCC cells. The roles of METTL16 on ferroptosis and HCC development were investigated in multiple cell lines, human HCC organoids, subcutaneous xenografts and MYC/Trp53-/- HCC model in hepatocyte-specific Mettl16 knockout and overexpression mice. The underlying mechanism was elucidated with MeRIP/RIP-qPCR, luciferase assay, Co-IP assay and Mass Spectrometry. The clinical significance and relevance were evaluated in human samples. RESULTS: High METTL16 expression confers ferroptosis resistance in HCC cells and mouse models, and promotes cell viability and tumor progression. Mechanistically, METTL16 collaborates with IGF2BP2 to modulate SENP3 mRNA stability in an m6A-dependent manner, and the latter impedes the proteasome-mediated ubiquitination degradation of Lactotransferrin (LTF) via de-SUMOylation. Elevated LTF expression facilitates the chelation of free iron and reduces liable iron pool level. SENP3 and LTF are implicated in METTL16-mediated HCC progression and anti-ferroptotic effects both in vivo and in vitro. Clinically, METTL16 and SENP3 expression were positively correlated, and high METTL16 and SENP3 expression predicts poor prognosis in human HCC samples. CONCLUSIONS: Our study reveals a new METTL16-SENP3-LTF signaling axis regulating ferroptosis and driving HCC development. Targeting this axis is a promising strategy for sensitizing ferroptosis and against HCC.

LONP1 alleviates ageing-related renal fibrosis by maintaining mitochondrial homeostasis.

Mitochondrial dysfunction is a pivotal event contributing to the development of ageing-related kidney disorders. Lon protease 1 (LONP1) has been reported to be responsible for ageing-related renal fibrosis; however, the underlying mechanism(s) of LONP1-driven kidney ageing with respect to mitochondrial disturbances remains to be further explored. The level of LONP1 was tested in the kidneys of aged humans and mice. Renal fibrosis and mitochondrial quality control were confirmed in the kidneys of aged mice. Effects of LONP1 silencing or overexpression on renal fibrosis and mitochondrial quality control were explored. In addition, N6-methyladenosine (m6A) modification and methyltransferase like 3 (METTL3) levels, the relationship between LONP1 and METTL3, and the impacts of METTL3 overexpression on mitochondrial functions were confirmed. Furthermore, the expression of insulin-like growth factor 2 mRNA binding protein 2 (IGF2BP2) and the regulatory effects of IGF2BP2 on LONP1 were confirmed in vitro. LONP1 expression was reduced in the kidneys of aged humans and mice, accompanied by renal fibrosis and mitochondrial dysregulation. Overexpression of LONP1 alleviated renal fibrosis and maintained mitochondrial homeostasis, while silencing of LONP1 had the opposite effect. Impaired METTL3-m6A signalling contributed at least in part to ageing-induced LONP1 modification, reducing subsequent degradation in an IGF2BP2-dependent manner. Moreover, METTL3 overexpression alleviated proximal tubule cell injury, preserved mitochondrial stability, inhibited LONP1 degradation, and protected mitochondrial functions. LONP1 mediates mitochondrial function in kidney ageing and that targeting LONP1 may be a potential therapeutic strategy for improving ageing-related renal fibrosis.

METTL3 inhibitor suppresses the progression of prostate cancer via IGFBP3/AKT pathway and synergizes with PARP inhibitor.

The RNA N6-methyladenosine (m6A) regulator METTL3 is an important regulatory gene in various progressive processes of prostate cancer (PCa). METTL3 inhibitors have been reported to possess potent tumor suppression capacity in some cancer types. Nevertheless, the detailed influence and mechanism of METTL3 inhibitors on PCa progression and their potential synergy with other drugs are poorly understood. In this study, we demonstrated that METTL3 was overexpressed and associated with poor survival in most PCa patients. METTL3 inhibitor STM2457 reduced m6A levels of PCa cells, thus inhibiting their proliferation, colony formation, migration, invasion, and stemness in vitro. Furthermore, STM2457 suppressed PCa progression in both the CDX and PDX models in vivo. MeRIP-seq analysis coupled with biological validation revealed that STM2457 influenced multiple biological processes in PCa cells, mainly through the IGFBP3/AKT pathway. We also proved that STM2457 induced DNA damage and showed synergistic anti-PCa effects with the PARP inhibitor olaparib both in vitro and in vivo. All in all, this work provides a novel therapeutic strategy for targeting RNA m6A modifications for the treatment of PCa and provides a meaningful reference for further clinical trials.

Understanding how methyltransferase-like 3 functions in lung diseases: From pathogenesis to clinical application.

Lung diseases have complex pathogenesis and treatment challenges, showing an obvious increase in the rate of diagnosis and death every year. Therefore, elucidating the mechanism for their pathogenesis and treatment ineffective from novel views is essential and urgent. Methyltransferase-like 3 (METTL3) is a novel post-transcriptional regulator for gene expression that has been implicated in regulating lung diseases, including that observed in chronic conditions such as pulmonary fibrosis (PF), pulmonary arterial hypertension (PAH), and chronic obstructive pulmonary disease (COPD), as well as acute conditions such as pneumonia, severe acute respiratory syndrome coronavirus 2 infection, and sepsis-induced acute respiratory distress syndrome. Notably, a comprehensive summary and analysis of findings from these studies might help understand lung diseases from the novel view of METTL3-regulated mechanism, however, such a review is still lacking. Therefore, this review aims to bridge such shortage by summarising the roles of METTL3 in lung diseases, establishing their interrelationships, and elucidating the potential applications of METTL3 regarding diagnosis, treatment, and prognosis. The analysis collectively suggests METTL3 is contributable to the onset and progression of these lung diseases, thereby prospecting METTL3 as a valuable biomarker for their diagnosis, treatment, and prognosis. In conclusion, this review offers elucidation into the correlation between METTL3 and lung diseases in both research and clinical settings and highlights potential avenues for exploring the roles of METTL3 in the respiratory system.

METTL3-mediated TIM1 promotes macrophage M1 polarization and inflammation through IGF2BP2-dependent manner.

Macrophage polarization and inflammation may play an important role in the development of sepsis. T-cell immunoglobulin mucin 1 (TIM1) has been demonstrated to promote macrophage inflammatory responses. However, whether TIM1 regulates macrophage polarization and inflammation to affect sepsis development remains unclear. Human monocytic leukemia cell line was induced into macrophages, followed by stimulated with LPS and IL-4 to induce M1 polarization and M2 polarization. The expression levels of TIM1, methyltransferase 3 (METTL3), and insulin like growth factor 2 mRNA binding protein 2 (IGF2BP2) were examined by qRT-PCR and western blot. IL-6, IL-1ß, and TNF-α levels were tested by ELISA. CD86+cell rate was analyzed by flow cytometry. The m6A methylation level of TIM1 was assessed by MeRIP assay. The interaction of between TIM1 and METTL3 or IGF2BP2 was assessed by dual-luciferase reporter assay and RIP assay. TIM1 knockdown repressed LPS-induced macrophage M1 polarization and inflammation. In terms of mechanism, METTL3 promoted TIM1 expression through m6A modification, and this modification could be recognized by IGF2BP2. Besides, knockdown of METTL3/IGF2BP2 suppressed LPS-induced macrophage M1 polarization and inflammation, while this effect could be eliminated by TIM1 overexpression. METTL3/IGF2BP2/TIM1 axis promoted macrophage M1 polarization and inflammation, which might provide potential target for sepsis treatment.

Effect of METTL3 Gene on Lipopolysaccharide Induced Damage to Primary Small Intestinal Epithelial Cells in Sheep.

Newborn lambs are susceptible to pathogenic bacterial infections leading to enteritis, which affects their growth and development and causes losses in sheep production. It has been reported that N6-methyladenosine (m6A) is closely related to innate immunity, but the effect of m6A on sheep small intestinal epithelial cells (IECs) and the mechanism involved have not been elucidated. Here, we investigated the effects of m6A on lipopolysaccharide (LPS)-induced inflammatory responses, apoptosis and oxidative stress in primary sheep IECs. First, the extracted IECs were identified by immunofluorescence using the epithelial cell signature protein cytokeratin 18 (CK18), and the cellular activity of IECs induced by different concentrations of LPS was determined by the CCK8 assay. Meanwhile, LPS could induce the upregulation of mRNA and protein levels of IECs cytokines IL1ß, IL6 and TNFα and the apoptosis marker genes caspase-3, caspase-9, Bax, and apoptosis rate, reactive oxygen species (ROS) levels and mRNA levels of CAT, Mn-SOD and CuZn-SOD, and METTL3 were found to be upregulated during induction. It was hypothesized that METTL3 may have a potential effect on the induction of IECs by LPS. Overexpression and knockdown of METTL3 in IECs revealed that a low-level expression of METTL3 could reduce the inflammatory response, apoptosis and ROS levels in LPS-induced IECs to some extent. The results suggest that METTL3 may be a genetic marker for potential resistance to cellular damage.

METTL3 Regulates the Translation of Oncogene Myc through m6A Modification and Promotes the Occurrence and Development of Cervical Cancer.

BACKGROUND: Cervical cancer (CC) is one of the major types of gynecological cancer, with a high global incidence and mortality rate. Methyltransferase-like 3 (METTL3), a key constituent of methyltransferase, plays a crucial role in various biological processes. Still, only a rare report has been made on its involvement in the progression of CC. Therefore, this study aims to investigate the impact of METTL3 in CC and its molecular mechanisms. METHODS: Gene expression datasets about CC were obtained from the Gene Expression Omnibus (GEO) database, and the expression of METTL3 and Myc was analyzed. Cell viability was detected after METTL3 knockdown in HeLa and SiHa cells, followed by cell counting Kit-8 (CCK-8) assays. The relative expression of METTL3 and Myc was detected via real-time quantitative PCR (qPCR) assays, and the protein expression was determined using Western blot. Meanwhile, cell invasion and migration capabilities were assessed utilizing transwell assays, and cell proliferation was detected using the EdU experiment. Furthermore, RNA methylation immunoprecipitation-qPCR detection was performed to determine the expression of Myc after N6-methyladenosine (m6A) modification. RESULTS: Analysis of the GEO database indicated elevated expression of METTL3 and Myc in CC tissues. Patients with high METTL3 expression had shorter disease-free survival, and patients with high Myc expression had shorter overall survival. Following the knockdown of METTL3, there was a significant reduction in the viability, proliferation, invasion, and migration abilities of HeLa and SiHa cells. Besides, the expression of METTL3 and Myc mRNAs and proteins was greatly reduced. The level of m6A Myc decreased significantly after METTL3 knockdown. CONCLUSIONS: METTL3 plays an important role in regulating cervical cancer cells. METTL3 promotes CC development through m6A modification to regulate the expression of the oncogene Myc.

Mettl1-dependent m7G tRNA modification is essential for maintaining spermatogenesis and fertility in Drosophila melanogaster.

Modification of guanosine to N7-methylguanosine (m7G) in the variable loop region of tRNA is catalyzed by the METTL1/WDR4 heterodimer and stabilizes target tRNA. Here, we reveal essential functions of Mettl1 in Drosophila fertility. Knockout of Mettl1 (Mettl1-KO) causes no major effect on the development of non-gonadal tissues, but abolishes the production of elongated spermatids and mature sperm, which is fully rescued by expression of a Mettl1-transgene, but not a catalytic-dead Mettl1 transgene. This demonstrates that Mettl1-dependent m7G is required for spermatogenesis. Mettl1-KO results in a loss of m7G modification on a subset of tRNAs and decreased tRNA abundance. Ribosome profiling shows that Mettl1-KO led to ribosomes stalling at codons decoded by tRNAs that were reduced in abundance. Mettl1-KO also significantly reduces the translation efficiency of genes involved in elongated spermatid formation and sperm stability. Germ cell-specific expression of Mettl1 rescues disrupted m7G tRNA modification and tRNA abundance in Mettl1-KO testes but not in non-gonadal tissues. Ribosome stalling is much less detectable in non-gonadal tissues than in Mettl1-KO testes. These findings reveal a developmental role for m7G tRNA modification and indicate that m7G modification-dependent tRNA abundance differs among tissues.

TRMT10C-mediated m7G modification of circFAM126A inhibits lung cancer growth by regulating cellular glycolysis.

The N7-methylguanosine (m7G) modification and circular RNAs (circRNAs) have been shown to play important roles in the development of lung cancer. However, the m7G modification of circRNAs has not been fully elucidated. This study revealed the presence of the m7G modification in circFAM126A. We propose the novel hypothesis that the methyltransferase TRMT10C mediates the m7G modification of circFAM126A and that the stability of m7G-modified circFAM126A is reduced. circFAM126A is downregulated in lung cancer and significantly inhibits lung cancer growth both in vitro and in vivo. The expression of circFAM126A correlates with the stage of lung cancer and with the tumour diameter, and circFAM126A can be used as a potential molecular target for lung cancer. The molecular mechanism by which circFAM126A increases HSP90 ubiquitination and suppresses AKT1 expression to regulate cellular glycolysis, ultimately inhibiting the progression of lung cancer, is elucidated. This study not only broadens the knowledge regarding the expression and regulatory mode of circRNAs but also provides new insights into the molecular mechanisms that regulate tumour cell metabolism and affect tumour cell fate from an epigenetic perspective. These findings will facilitate the development of new strategies for lung cancer prevention and treatment.

Regulatory effect of N6-methyladenosine on tumor angiogenesis.

Previous studies have demonstrated that genetic alterations governing epigenetic processes frequently drive tumor development and that modifications in RNA may contribute to these alterations. In the 1970s, researchers discovered that N6-methyladenosine (m6A) is the most prevalent form of RNA modification in advanced eukaryotic messenger RNA (mRNA) and noncoding RNA (ncRNA). This modification is involved in nearly all stages of the RNA life cycle. M6A modification is regulated by enzymes known as m6A methyltransferases (writers) and demethylases (erasers). Numerous studies have indicated that m6A modification can impact cancer progression by regulating cancer-related biological functions. Tumor angiogenesis, an important and unregulated process, plays a pivotal role in tumor initiation, growth, and metastasis. The interaction between m6A and ncRNAs is widely recognized as a significant factor in proliferation and angiogenesis. Therefore, this article provides a comprehensive review of the regulatory mechanisms underlying m6A RNA modifications and ncRNAs in tumor angiogenesis, as well as the latest advancements in molecular targeted therapy. The aim of this study is to offer novel insights for clinical tumor therapy.