Search Results (206)

Epitranscriptomic modifications, particularly RNA methylations, have emerged as regulators of gene expression, with their dysregulation acting as a key factor in tumorigenesis and metastatic progression. This review evaluates the therapeutic landscapes of N⁶-methyladenosine (m⁶A) and N¹-methyladenosine (m¹A) modifications in cancer. While the m⁶A machinery predominantly dictates mRNA turnover and stability, the m¹A network is uniquely positioned to drive translational reprogramming, allowing malignant cells to endure severe microenvironmental stress and evade cell death. Despite positional and chemical differences, these modifications exhibit profound epitranscriptomic crosstalk through shared regulatory proteins. Here, we comprehensively analyze current pharmacological strategies targeting the m⁶A axis, highlighting the transition from classical small-molecule inhibitors of regulatory proteins of these methylations, such as methyltransferase-like 3 (METTL3), fat mass and obesity-associated protein (FTO), and AlkB homolog 5 (ALKBH5), to the novel event-driven approach of proteolysis-targeting chimeras (PROTACs). Furthermore, we assess the emerging therapeutic potential of the m¹A regulatory machinery, positioning tRNA methyltransferase 6/61A (TRMT6/61A) writers and AlkB homolog 1 to 3 (ALKBH1-3) erasers as promising therapeutic targets. Finally, we discuss clinical successes and current translational obstacles, including off-target toxicity, pharmacokinetic limitations, and epitranscriptomic escape, emphasizing that site-specific modulation and smart precision therapies will dictate the future of oncology. Full article

Splicing factor 3b1 (SF3B1), a component of U2 small nuclear ribonucleoprotein (U2 snRNP), has been known for its essential roles in pre-mRNA splicing and alternative splicing. Here we show that knocking down (KD) of SF3B1 broadly induced a significant reduction in mRNA expression in the genome. One of the genes whose expression is reduced by SF3B1 KD is methyl-transferase-like 3 (METTL3), a writer of N6-methyladenosine (m⁶A). We demonstrate that expression of both METTL3 mRNA and protein is affected by SF3B1 KD, which further decreases the m⁶A RNA expression level. m⁶A-seq indicates that SF3B1 KD affects m⁶A distribution within multiple genes in the genome. In addition, a high proportion of hypo-methylation events by SF3B1 KD (~70%) are overlapped in METTL3 KD cells, and a conserved m⁶A motif is observed in the hypo-methylated regions as in SF3B1 KD cells, suggesting the m⁶A decrease by SF3B1 is a direct effect of the reduced METTL3 expression. Furthermore, RT-qPCR using unlabeled RNA and 5-Bromouridine (BrU)-labeled nascent RNA and actinomycin D treatment demonstrates that transcription of METTL3 is significantly reduced but the mRNA decay rate is not altered, suggesting that METTL3 expression is altered at the transcription level. We further show that SF3B1 interacts with RNA polymerase (Pol) II in the RNA independent manner, further indicating the involvement of SF3B1 in transcription. Lastly, we demonstrate that the transcription inactive H3K27me3 on the METTL3 promoter was significantly increased whereas transcription active H3K4me3 was not changed by SF3B1 KD. Taken together, we conclude that reduced SF3B1 expression suppresses the transcription of METTL3 and inhibits m⁶A RNA expression. Full article

Succinate, a tricarboxylic acid (TCA) cycle intermediate, is the essential signal molecule that links metabolic signals and inflammation. Dietary succinate supplementation has been reported to prevent obesity induced by a high-fat diet (HFD). However, the underlying mechanism remains elusive. Here, we found that dietary succinate elevated the serum succinate levels. Meanwhile, we found succinate increased methyltransferaselike 3 (METTL3) protein expression in brown adipocytes, thereby elevating N⁶-methyladenosine (m⁶A) levels in Hypoxia-inducible factor1-alpha (Hif1a) mRNA. Hif1a mRNA is recognized by the m⁶A-binding protein YTH domain-containing family protein 1 (YTHDF1), facilitating HIF1A protein expression. HIF1A activates the transcription of thermogenic genes, ultimately increasing brown adipose energy expenditure. Together, our research provided new insights into the effect of succinate on m⁶A modification in brown adipose tissue thermogenesis. Full article

Colorectal cancer (CRC) remains a leading cause of cancer-related mortality worldwide, characterized by a multi-step carcinogenesis process involving genetic mutations and epigenetic alterations. Despite advances in screening and therapy, challenges such as treatment resistance, recurrence, and metastasis persist. Emerging evidence highlights the critical role of epigenetic modifications, particularly N7-methylguanosine (m7G), in post-transcriptional regulation. This ubiquitous RNA modification participates extensively in tumor biological behaviors by regulating RNA stability, processing, and translation. Studies have shown that dysregulation of m7G modification is closely associated with adverse clinical outcomes in CRC. This review systematically summarizes the biological functions of m7G modification and its key regulatory proteins (such as METTL1/WDR4, eIF4E, etc.), with a focus on their roles in the pathogenesis, progression, prognosis, and diagnosis of, as well as therapy for, colorectal cancer. m7G modification and related molecules hold potential as novel biomarkers and therapeutic targets, thereby providing new strategies for the precision diagnosis and treatment of colorectal cancer. Full article

The flavor of rabbit meat has always been a major factor hindering the development of the rabbit industry. One of the main factors affecting the flavor of rabbit meat is intramuscular fat. N6-methyladenosine (m⁶A) regulates multiple aspects of the physiology of animals. In this study, qRT-PCR and m⁶A-qPCR were used to identify genes and methylation levels. AAV virus was used as a vector to overexpress genes. To explore the regulatory mechanism of m⁶A on intramuscular fat in rabbits, we first explored the regulation of the LPL gene of rabbits by m⁶A at the cellular level using interfering RNA. Subsequently, we further validated the mechanism and explored the regulation of metabolites by LPL genes in living dorsal muscles. The results demonstrate that METTL3 inhibited LPL expression through m⁶A modification under the recognition of YTHDF2 in adipocytes and muscles. LPL promotes adipocyte differentiation and intramuscular fat deposition. In addition, LPL regulates intramuscular fat deposition through L-Glutamine/multiple pathways and 3-Methyl-L-histidine. This study confirms that m⁶A can affect the expression of the LPL gene in rabbits, thereby regulating the IMF of rabbit meat by L-Glutamine/multiple pathways and 3-Methyl-L-histidine. This study lays the molecular foundation for cultivating high-quality rabbit meat. Full article

Breast cancer remains a leading cause of cancer-related mortality worldwide, with epigenetic mechanisms like N⁶ methyladenosine (m⁶A) modification playing a crucial role in tumorigenesis. The interaction between microRNAs and m⁶A regulators, such as the methyltransferase METTL14, is increasingly recognized as a key pathway in oncogenesis. This study investigated whether miR-30c-2-3p regulates METTL14 expression to influence global m⁶A levels and cell migration in breast epithelial (MCF12A) and breast cancer (MCF7) cell lines. Following transfection with miR-30c-2-3p mimics, successful overexpression was confirmed in both cell lines. Subsequent RT-qPCR and Western blotting analyses demonstrated that METTL14 mRNA and protein levels were significantly reduced at 24 and 48 h post-transfection (p < 0.05). Concurrently, global m⁶A RNA methylation levels decreased, with a more pronounced reduction observed in MCF12A cells (p < 0.001). Functionally, wound healing assays revealed that miR-30c-2-3p significantly inhibited migration, reducing wound closure by 30–44% in MCF7 cells and by 66–72% in MCF12A cells. These findings reveal a novel regulatory axis involving miR-30c-2-3p, METTL14, and m⁶A, suggesting that miR-30c-2-3p functions as a tumor suppressor and represents a promising biomarker and therapeutic target in breast cancer. Full article

Uterine leiomyoma (UL) is characterized by excessive proliferation, extracellular matrix accumulation, and inflammatory activation, yet its upstream regulatory mechanisms remain incompletely defined. Here, we investigated the role of METTL3-associated signaling in mediating the anti-leiomyoma effects of quercetin. Quercetin significantly inhibited proliferation and induced apoptosis in UL cells, accompanied by suppression of inflammatory cytokine production. Transcriptomic profiling revealed that METTL3 silencing was associated with enrichment of MAPK and inflammation-related pathways. Mechanistically, quercetin downregulated METTL3 expression and suppressed phosphorylation of MEK, ERK, JNK, and p38, whereas METTL3 overexpression partially reversed these effects, supporting a functional role of METTL3 in mediating MAPK pathway activation. Consistently, METTL3 knockdown recapitulated the anti-proliferative, pro-apoptotic, and anti-inflammatory effects of quercetin. In a hormone-induced UL rat model, quercetin attenuated uterine enlargement, fibrosis, and proliferative activity, accompanied by decreased METTL3 expression and MAPK activation. Collectively, these findings demonstrate that quercetin suppresses UL progression, at least in part, through modulation of METTL3-mediated MAPK signaling, highlighting METTL3 as a critical regulatory node and a potential therapeutic target in UL. Full article

The buffalo is an important agricultural species due to its many productive characteristics, which encourage its use worldwide. Uncovering the processes of selective sweeps is critical for a comprehensive understanding of genomic mechanisms that influence phenotypic differentiation in buffalo. This study aims to refine signatures of selection in Bulgarian (BUL), Hungarian (HUN), and Romanian (ROM) buffalo breeds using runs of homozygosity (ROHs), the integrated haplotype score (iHS), the standardized log-ratio of the integrated site-specific extended haplotype homozygosity (EHH) between pairs of breeds test (Rsb), and cross-population EHH (XP-EHH) approaches. The SNP dataset of 160 genotypes from BUL, HUN, and ROM buffalo breeds was genotyped using the Axiom^® Buffalo Genotyping Array 90K from Affymetrix. By combining the ROH, iHS, Rsb, and XP-EHH methods, we identified many important genomic regions and candidate genes associated with milk production (SLC24A2, TMEM132C, and ALCAM), reproduction (CSMD1, NTS, PLIN2, GPC5, and FSHR), growth (MYOM2, CLN8, and RRAGA), immune response (METTL25, MLLT3, NAALADL2, and GAB2), and adaptation (ADAMTSL1) in BUL, HUN, and ROM buffalo breeds. Our findings highlighted selection signals and genes related to important economic traits in the BUL, HUN, and ROM buffalo breeds, providing promising candidate genes for further research and inclusion in conservation and selection plans for these breeds. Full article

m⁶A represents a prevalent epitranscriptomic modification in eukaryotes. The dynamic balance of m⁶A modification is governed by methyltransferases (writers), demethylases (erasers), and binding proteins (readers). m⁶A regulators are integral to critical biological processes, including embryonic development, cell differentiation, and stress responses. B. xylophilus, a highly destructive invasive plant-parasitic nematode, has caused considerable ecological and economic damage worldwide. However, the m⁶A regulatory system in PWNs has not yet been investigated. In this study, we systematically identified 21 m⁶A regulators in PWNs, including 10 writers, 6 erasers, and 5 readers, which belong to the METTL, ALKBH, and KH/RRM families. Phylogenetic and domain analyses revealed the evolutionary conservation and functional diversification of these protein families. Expression profiling indicated stage-specific expression patterns of m⁶A regulators during the egg, larval, diapause, and adult stages. Furthermore, significant responses were observed under low-temperature treatment, β-pinene exposure, and infection of Pinus thunbergii seedlings, with ALKBH family members exhibiting upregulation under all three stress conditions. Notably, unlike most eukaryotes, the PWN lacks canonical FTO/ALKBH5 demethylases and YTH-domain readers, instead relying on ALKBH6/8 and KH/RRM proteins. These findings suggest that this non-canonical m⁶A regulatory mechanism may contribute to the development and pathogenesis of B. xylophilus. Full article

Chlamydia trachomatis has evolved sophisticated mechanisms to manipulate key host cell signaling pathways to facilitate its intracellular reproduction. N6-methyladenosine (m6A) in RNA is known to regulate various physiological and disease processes, and is also involved in the regulation of pathogenic and developmental processes in many pathogens. However, the specific impact of m6A modification on the intracellular growth of C. trachomatis remains poorly understood. In this study, our analysis of the m6A methylation profiles of host cell mRNAs following C. trachomatis infection revealed significant alterations in the distribution of m6A modifications, methylation motifs, and m6A-modified host target genes. We further demonstrate that chlamydial intracellular reproduction is mediated by the host methyltransferase-like (METTL) enzyme METTL14. Silencing METTL14 significantly reduced the reproduction efficiency of C. trachomatis. Mechanistically, C. trachomatis activates the Mitogen-Activated Protein Kinase (MAPK) and Phosphatidylinositol 3-kinase/Protein Kinase B (PI3K/AKT) signaling pathways through METTL14, thereby inhibiting host cell apoptosis and promoting intracellular bacterial reproduction. Collectively, these findings identify METTL14 as a key host factor for chlamydial intracellular reproduction, providing new mechanistic insights and potential targets for therapeutic intervention. Full article

Enteroviruses are positive-sense single-stranded RNA viruses and common pathogens that are responsible for diverse public health diseases. To facilitate the study of the virus biology and pathogenesis of enterovirus, we developed a rapid method for construction of the enteroviral cDNA clones including enterovirus A71 (EV-A71) and coxsackievirus B5 (CVB5). As described for EV-A71, the full-length cDNA of CVB5 was amplified by long-distance PCR and cloned into a T7 promoter-containing plasmid using directional seamless cloning technology. The virus was successfully rescued by single transfection into cells stably expressing T7 polymerase and exhibited characteristics similar to the parental virus. Next, through systematic construction and the optimization of the EV-A71 and CVB5 reporter viruses, we successfully generated two novel reporter virus panels with high virus titers, rapid replication, and relatively stable genetic inheritance across passages using the new fluorescence proteins mScarlet3-H and the smallest miRFP670nano3. Analysis of critical determinants for the reporter virus construction revealed that reporter gene sizes, genomic insertion sites, and the usage of protease recognition sites are crucial parameters. The EV-A71 and CVB5 reporter viruses enable antiviral drug evaluation, as demonstrated by our identification of gemcitabine as a broad-spectrum inhibitor of both viruses. These systems also facilitate the functional interrogation of host factors, exemplified by our discovery that METTL3 promotes EV-A71 and CVB5 replication. These reverse genetic tools, including infectious cDNA clones and reporter viruses, will advance basic enterovirus biology and accelerate antiviral drug discovery. Full article

Background: Tumor invasion is the central barrier to effective immunotherapy in lung adenocarcinoma (LUAD) and glioblastoma. Cell adhesion signaling critically shapes tumor–microenvironment interactions, yet the upstream regulators coordinating these invasive programs at single-cell resolution remain incompletely understood. Methyltransferase Like protein 7B (METTL7B) has recently emerged as a candidate oncogenic regulator, but its lineage-specific functions and the potential downstream effectors are unclear. Methods: We integrated publicly available single-cell RNA sequencing datasets from LUAD and glioblastoma with The Cancer Genome Atlas (TCGA) transcriptomic analyses to resolve METTL7B-associated malignant cell states and microenvironmental interactions. Functional enrichment analyses identified invasion- and focal adhesion pathways linked to METTL7B expression. Gain- and loss-of-function experiments were conducted in LUAD and glioblastoma cell lines to validate downstream cell adhesion effectors. Spatial expression patterns were examined using immunofluorescence, and transwell assays were used to assess migratory and invasive phenotypes. Results: Single-cell analyses revealed that METTL7B was selectively enriched in malignant epithelial cells in LUAD and glioblastoma and defined a transcriptional program characterized by cell adhesion signaling. Integrin Alpha 3 (ITGA3) emerged as a conserved downstream effector of METTL7B, with progressive upregulation from minimally invasive to invasive LUAD and glioblastoma. Functional perturbation confirmed that METTL7B enhances tumor cell migration and invasion through integrin-associated pathways. Conclusions: METTL7B acts as a potential lineage-enriched regulator of invasive tumor states by activating cell adhesion signaling in LUAD and glioblastoma. These findings position METTL7B as a putative prognostic factor for strategies aimed at limiting invasion in lung cancer and glioblastoma. Full article

Background: This study investigates the role of N6-methyladenosine (m6A) regulators in osteoporosis (OP) and their interplay with the immune microenvironment, aiming to identify potential m6A-related biomarkers for OP risk assessment and treatment. Methods: Transcriptomic data from GEO datasets were analyzed for differential expression of 22 m6A regulators and immune infiltration patterns. Consensus clustering and m6Ascore grouping defined molecular subtypes, while machine learning algorithms identified potential biomarkers, leading to the construction and validation of a nomogram. Experimental validation involved peripheral blood monocytes (PBMCs) transcriptome sequencing and Western blot of bone tissue. Results: FTO, HNRNPC, and METTL4 were upregulated, while CBLL1 and YTHDF2 were downregulated in OP, with two distinct m6A modification patterns and immune phenotypes identified. METTL4, HIRA, MATN4, and YTHDF2 were selected as potential biomarkers, and the nomogram demonstrated favorable predictive performance in training and external datasets. Single-cell RNA sequencing confirmed the cellular distribution of these biomarkers. HIRA heterogeneity in Marrow Mesenchymal Stem Cells (BMSCs) was associated with distinct cell–cell communication patterns. Transcriptome sequencing confirmed HIRA RNA downregulation in OP PBMCs, and Western blot verified decreased HIRA protein in OP bone tissue. Conclusions: This study establishes a potential m6A-related biomarker signature for OP and provides multi-level experimental evidence that HIRA is a consistently downregulated biomarker, linking epigenetic modification to immune dysregulation in osteoporosis. Full article

Glucosylceramide synthase (GCS) catalyzes ceramide glycosylation in response to cell stress that produces glucosylceramide and other glycosphingolipids. GCS overexpression is a cause of drug resistance and enriches cancer stem cells (CSCs) during cancer chemotherapy. Previous studies showed that GCS modulates the expression of p53 mutants and oncogenic gain-of-function (GOF) in heterozygous knock-in cell models (TP53 R273H^−/+). However, it is unclear whether GCS can modulate the effects of homozygous p53 mutations, which are common in many cancer cases. We report herewith that inhibition of GCS, via UGCG knockout and using an inhibitor (Genz-161), effectively re-sensitizes drug resistance and diminishes CSCs in colon cancer cells carrying the homozygous p53 R273H mutation. In aggressive WiDr cells carrying TP53 R273H mutation, knockout of UGCG gene using CRISPR/Cas9 editing or inhibition of GCS with Genz-161 sensitized cancer cells to oxaliplatin, irinotecan and paclitaxel. With decreased ceramide glycosylation in lipidomic profiling, both UGCG knockout and Genz-161 treatments substantially decreased wound healing, and diminished CSCs and tumor growth under chemotherapy. Interestingly, inhibition of RNA m⁶A methylation by neplanocin A markedly increased p53 function and reversed drug resistance. Mechanistic investigation revealed that GCS inhibition downregulated methyltransferase-like 3 (METTL3) expression and decreased RNA-m⁶A modification on mutant p53 R273H effects. Altogether, our findings demonstrate that ceramide glycosylation promotes METTL3 expression and RNA m⁶A methylation in response to drug-induced stress, thereby promoting mutant p53 expression and associated GOF. Conversely, inhibition of GCS can diminish CSCs and drug resistance via reduction in m⁶A modification and advance of p53-assocaited tumor suppressive function. GCS inhibition is an achievable approach for mutant cancer treatment. Full article

Background: Small nucleolar RNAs (snoRNAs) are emerging regulators of tumorigenesis, yet their pan-cancer landscape and immunological roles remain poorly defined. This study investigates the expression pattern, prognostic significance, and immune correlation of SNORA12 across cancers, with mechanistic validation in osteosarcoma. Methods: We integrated RNA-seq data from the TCGA, TARGET, and GTEx databases to evaluate SNORA12 expression and its prognostic value using Cox regression and Kaplan–Meier analyses (progression-free survival, PFS). The correlation between SNORA12 and the tumor immune microenvironment was assessed using six independent algorithms (TIMER, EPIC, CIBERSORT, IPS, MCP-counter, xCELL). In vitro, the regulatory effect of SNORA12 on the immune checkpoint TIGIT was validated by overexpression and knockdown experiments in osteosarcoma cell lines (SW1353, U2OS) and NK cells. Results: SNORA12 expression exhibited significant tumor-type specificity. High SNORA12 expression was associated with poor prognosis in glioma (HR = 1.31, p = 0.006) but favorable outcomes in pancreatic (HR = 0.51, p = 0.01) and breast cancer (HR = 0.56, p = 0.02). Immunologically, SNORA12 showed robust positive correlations with CD8+ T cell infiltration in thyroid carcinoma (THCA) and lung adenocarcinoma (LUAD) across multiple algorithms. Notably, SNORA12 expression was positively correlated with m6A modifiers METTL3 and YTHDF1, and negatively correlated with the demethylase FTO. Experimentally, overexpression of SNORA12 in osteosarcoma cells and primary NK cells significantly upregulated TIGIT at both the mRNA and protein levels, while SNORA12 knockdown in NK92 cells reduced TIGIT expression. Conclusions: This pan-cancer analysis positions SNORA12 as a tumor type-specific prognostic biomarker and reveals its novel role as a positive regulator of TIGIT in osteosarcoma, offering a potential mechanistic link between snoRNA dysregulation and immune evasion. Full article