FTO m6A Demethylase in Obesity and Cancer: Implications and Underlying Molecular Mechanisms

FTO attenuates TNF-α-induced damage of proximal tubular epithelial cells in acute pancreatitis-induced acute kidney injury via targeting AQP3 in an N6-methyladenosine-dependent manner

BACKGROUND

Acute kidney injury (AKI) is a frequent complication of severe acute pancreatitis (SAP). Previous investigations have revealed the involvement of FTO alpha-ketoglutarate-dependent dioxygenase (FTO) and aquaporin 3 (AQP3) in AKI. Therefore, the aim of this study is to explore the association of FTO and AQP3 on proximal tubular epithelial cell damage in SAP-induced AKI.

METHODS

An in-vitro AKI model was established in human proximal tubular epithelial cells (PTECs) HK-2 via tumor necrosis factor-α (TNF-α) induction (20 ng/mL), after which FTO and AQP3 expression was manipulated and quantified by quantitative real-time PCR and Western blotting. The viability and apoptosis of PTECs under various conditions, and reactive oxygen species (ROS), superoxide dismutase (SOD), and malonaldehyde (MDA) levels within these cells were measured using commercial assay kits and flow cytometry. Methylated RNA immunoprecipitation and mRNA stability assays were performed to elucidate the mechanism of FTO-mediated N6-methyladenosine (m6A) modification. Western blotting was performed to quantify β-catenin protein levels in the PTECs.

RESULTS

FTO overexpression attenuated the TNF-α-induced decrease in viability and SOD levels, elevated apoptosis, increased levels of ROS and MDA, and diminished TNF-α-induced AQP3 expression and reduced β-catenin expression, but its silencing led to contradictory results. FTO negatively modulates AQP3 levels in RTECs in an m6A-depednent manner and compromises AQP3 stability. In addition, all FTO overexpression-induced effects in TNF-α-induced PTECs were neutralized following AQP3 upregulation.

CONCLUSION

FTO alleviates TNF-α-induced damage to PTECs in vitro by targeting AQP3 in an m6A-dependent manner.

Comprehensive analysis of m6A methylome alterations after azacytidine plus venetoclax treatment for acute myeloid leukemia by nanopore sequencing

N6 adenosine methylation (m6A), one of the most prevalent internal modifications on mammalian RNAs, regulates RNA transcription, stabilization, and splicing. Growing evidence has focused on the functional role of m6A regulators on acute myeloid leukemia (AML). However, the global m6A levels after azacytidine (AZA) plus venetoclax (VEN) treatment in AML patients remain unclear. In our present study, bone marrow (BM) sample pairs (including pre-treatment [AML] and post-treatment [complete remission (CR)] samples) were harvested from three AML patients who had achieved CR after AZA plus VEN treatment for Nanopore direct RNA sequencing. Notably, the amount of m6A sites and the m6A levels in CR BMs was significantly lower than those in the AML BMs. Such a significant reduction in the m6A levels was also detected in AZA-treated HL-60 cells. Thirteen genes with decreased m6A and expression levels were identified, among which three genes (HPRT1, SNRPC, and ANP32B) were closely related to the prognosis of AML. Finally, we speculated the mechanism via which m6A modifications affected the mRNA stability of these three genes. In conclusion, we illustrated for the first time the global landscape of m6A levels in AZA plus VEN treated AML (CR) patients and revealed that AZA had a significant demethylation effect at the RNA level in AML patients. In addition, we identified new biomarkers for AZA plus VEN-treated AML via Nanopore sequencing technology in RNA epigenetics.

Functions and mechanisms of RNA m6A regulators in breast cancer (Review)

Breast cancer (BC) is a major malignant tumor in females and the incidence rate of BC has increased worldwide in recent years. N6‑methyladenosine (m6A) is a methylation modification that occurs extensively in eukaryotic RNA. The abnormal expression of m6A and related regulatory proteins can activate or inhibit certain signal pathways or oncogenes, thus affecting the proliferation, metastasis and prognosis of BC. Numerous studies have shown that m6A regulator disorder exists in BC, and this disorder can be reversed. Therefore, m6A is predicted as a potential therapeutic target for BC. However, the molecular mechanism of m6A RNA methylation regulating the occurrence and development of BC has not been comprehensively elucidated. In this review article, the functions of various m6A regulators and the specific mechanisms of certain regulators of the progress of BC were summarized. Furthermore, the dual role of RNA methylation in tumor progression was discussed, concluding that RNA methylation can not only lead to tumorigenesis but at times give rise to inhibition of tumor formation. In addition, further comprehensive analysis on mechanisms of m6A regulators in BC is conducive to screening effective potential targets and formulating targeted treatment strategies, which will provide new methods for the prevention and treatment of BC.

Fat mass and obesity-associated protein (FTO)-induced upregulation of flotillin-2 (FLOT2) contributes to cancer aggressiveness in diffuse large B-cell lymphoma (DLBCL) via activating the PI3K/Akt/mTOR signal pathway

The role of fat mass and obesity-associated protein (FTO)-mediated N6-methyladenosine (m6A)-demethylation has been investigated in various types of cancers, but it is still unclear whether FTO participates in the progression of diffuse large B-cell lymphoma (DLBCL). Here, by conducting Real-Time qPCR and Western Blot analysis, we verified that FTO was especially enriched in the DLBCL cells (RCK-8, LY-3, DHL-6 and U2932) compared to normal WIL2S cells. Then, the overexpression and silencing vectors for FTO were delivered into the LY-3 and U2932 cells, and our functional experiments confirmed that silencing of FTO suppressed cell viability and division, and induced apoptotic cell death in the DLBCL cells, whereas FTO-overexpression exerted opposite effects. Further mechanical experiments showed that FTO demethylated m6A modifications in flotillin-2 (FLOT2) mRNA to sustain its stability for FLOT2 upregulation, and elevated FLOT2 subsequently increased the expression levels of phosphorylated PI3K (p-PI3K), p-Akt and p-mTOR to activate the tumor-initiating PI3K/Akt/mTOR signal pathway. Of note, FLOT2 also serve as an oncogene to enhance cancer malignancy in DLBCL, and the rescuing experiments showed that FTO-ablation induced suppressing effects on the malignant phenotypes in DLBCL were all abrogated by overexpressing FLOT2. Taken together, those data hinted that FTO-mediated m6A-demethylation upregulated FLOT2 to activate the downstream PI3K/Akt/mTOR signal pathway, leading to the aggressiveness of DLBCL, which potentially provided diagnostic, therapeutic and prognostic biomarkers for DLBCL.

RNA N6-methyladenosine modifications in urological cancers: from mechanism to application

The N6-methyladenosine (m6A) modification is the most common modification of messenger RNAs in eukaryotes and has crucial roles in multiple cancers, including in urological malignancies such as renal cell carcinoma, bladder cancer and prostate cancer. The m6A RNA modification is controlled by three types of regulators, including methyltransferases (writers), demethylases (erasers) and RNA-binding proteins (readers), which are responsible for gene regulation at the post-transcriptional level. This Review summarizes the current evidence indicating that aberrant or dysregulated m6A modification is associated with urological cancer development, progression and prognosis. The complex and context-dependent effects of dysregulated m6A modifications in urological cancers are described, along with the potential for aberrantly expressed m6A regulators to provide valuable diagnostic and prognostic biomarkers as well as new therapeutic targets.

Risk of Fat Mass- and Obesity-Associated Gene-Dependent Obesogenic Programming by Formula Feeding Compared to Breastfeeding

It is the purpose of this review to compare differences in postnatal epigenetic programming at the level of DNA and RNA methylation and later obesity risk between infants receiving artificial formula feeding (FF) in contrast to natural breastfeeding (BF). FF bears the risk of aberrant epigenetic programming at the level of DNA methylation and enhances the expression of the RNA demethylase fat mass- and obesity-associated gene (FTO), pointing to further deviations in the RNA methylome. Based on a literature search through Web of Science, Google Scholar, and PubMed databases concerning the dietary and epigenetic factors influencing FTO gene and FTO protein expression and FTO activity, FTO's impact on postnatal adipogenic programming was investigated. Accumulated translational evidence underscores that total protein intake as well as tryptophan, kynurenine, branched-chain amino acids, milk exosomal miRNAs, NADP, and NADPH are crucial regulators modifying FTO gene expression and FTO activity. Increased FTO-mTORC1-S6K1 signaling may epigenetically suppress the WNT/β-catenin pathway, enhancing adipocyte precursor cell proliferation and adipogenesis. Formula-induced FTO-dependent alterations of the N6-methyladenosine (m6A) RNA methylome may represent novel unfavorable molecular events in the postnatal development of adipogenesis and obesity, necessitating further investigations. BF provides physiological epigenetic DNA and RNA regulation, a compelling reason to rely on BF.

MICAL1 promotes the proliferation in acute myeloid leukemia and is associated with clinical prognosis and immune infiltration

Acute myeloid leukemia (AML) is one of the most common hematopoietic malignancies that has a poor prognosis and a high rate of relapse. Dysregulated metabolism plays an important role in AML progression. This study aimed to conduct a comprehensive analysis of MRGs using TCGA and GEO datasets and further explore the potential function of critical MRGs in AML progression. In this study, we identified 17 survival-related differentially expressed MRGs in AML using TCGA and GEO datasets. The 150 AML samples were divided into three molecular subtypes using 17 MRGs, and we found that three molecular subtypes exhibited a different association with ferroptosis, cuproptosis and m6A related genes. Moreover, a prognostic signature that comprised nine MRGs and had good predictive capacity was established by LASSO-Cox stepwise regression analysis. Among the 17 MRGs, our attention focused on MICAL1 which was highly expressed in many types of tumors, including AML and its overexpression was also confirmed in several AML cell lines. We also found that the expression of MICAL1 was associated with several immune cells. Moreover, functional experiments revealed that knockdown of MICAL1 distinctly suppressed the proliferation of AML cells. Overall, this study not only contributes to a deeper understanding of the molecular mechanisms underlying AML but also provides potential targets and prognostic markers for AML treatment. These findings offer robust support for further research into therapeutic strategies and mechanisms related to AML, with the potential to improve the prognosis and quality of life for AML patients. Nevertheless, further research is needed to validate these findings and explore more in-depth molecular mechanisms.

RNA demethylase FTO participates in malignant progression of gastric cancer by regulating SP1-AURKB-ATM pathway

Gastric cancer (GC) is the 5th most prevalent cancer and the 4th primary cancer-associated mortality globally. As the first identified m6A demethylase for removing RNA methylation modification, fat mass and obesity-associated protein (FTO) plays instrumental roles in cancer development. Therefore, we study the biological functions and oncogenic mechanisms of FTO in GC tumorigenesis and progression. In our study, FTO expression is obviously upregulated in GC tissues and cells. The upregulation of FTO is associated with advanced nerve invasion, tumor size, and LNM, as well as the poor prognosis in GC patients, and promoted GC cell viability, colony formation, migration and invasion. Mechanistically, FTO targeted specificity protein 1 and Aurora Kinase B, resulting in the phosphorylation of ataxia telangiectasia mutated and P38 and dephosphorylation of P53. In conclusion, the m6A demethylase FTO promotes GC tumorigenesis and progression by regulating the SP1-AURKB-ATM pathway, which may highlight the potential of FTO as a diagnostic biomarker for GC patients' therapy response and prognosis.

N6-Methyladenosine-Modified KREMEN2 Promotes Tumorigenesis and Malignant Progression of High-Grade Serous Ovarian Cancer

High-grade serous ovarian cancer (HGSOC) remains the most lethal female cancer by far. Herein, clinical HGSOC samples had higher N6-methyladenosine (m6A) modification than normal ovarian tissue, and its dysregulation had been reported to drive aberrant transcription and translation programs. However, Kringle-containing transmembrane protein 2 (KREMEN2) and its m6A modification have not been fully elucidated in HGSOC. In this study, the data from the high-throughput messenger RNA (mRNA) sequencing of clinical samples were processed using the weighted correlation network analysis and functional enrichment analysis. Results revealed that KREMEN2 was a driver gene in the tumorigenesis of HGSOC and a potential target of m6A demethylase fat-mass and obesity-associated protein (FTO). KREMEN2 and FTO levels were upregulated and downregulated, respectively, and correlation analysis showed a significant negative correlation in HGSOC samples. Importantly, upregulated KREMEN2 was remarkably associated with lymph node metastasis, distant metastasis, peritoneal metastasis, and high International Federation of Gynecology and Obstetrics stage (Ⅲ/Ⅳ), independent of the age of patients. KREMEN2 promoted the growth of HGSOC in vitro and in vivo, which was dependent on FTO. The methylated RNA immunoprecipitation qPCR and RNA immunoprecipitation assays were performed to verify the m6A level and sites of KREMEN2. FTO overexpression significantly decreased m6A modification in the 3' and 5' untranslated regions of KREMEN2 mRNA and downregulated its expression. In addition, we found that FTO-mediated m6A modification of KREMEN2 mRNA was recognized and stabilized by the m6A reader IGF2BP1 rather than by IGF2BP2 or IGF2BP3. This study highlights the m6A modification of KREMEN2 and extends the importance of RNA epigenetics in HGSOC.

The Impact of Haplotypes of the FTO Gene, Lifestyle, and Dietary Patterns on BMI and Metabolic Syndrome in Polish Young Adult Men

BACKGROUND

Variants in fat mass and the obesity-associated protein (FTO) gene have long been recognized as the most significant genetic predictors of body fat mass and obesity. Nevertheless, despite the overall evidence, there are conflicting reports regarding the correlation between different polymorphisms of the FTO gene and body mass index (BMI). Additionally, it is unclear whether FTO influences metabolic syndrome (MetS) through mechanisms other than BMI's impact. In this work, we aimed to analyze the impact of the following FTO polymorphisms on the BMI as well as MetS components in a population of young adult men.

METHODS

The patient group consisted of 279 Polish young adult men aged 28.92 (4.28) recruited for the MAGNETIC trial. The single-nucleotide polymorphisms (SNPs), located in the first intron of the FTO gene, were genotyped, and the results were used to identify "protective" and "risk" haplotypes and diplotypes based on the literature data. Laboratory, as well as anthropometric measurements regarding MetS, were performed. Measured MetS components included those used in the definition in accordance with the current guidelines. Data regarding dietary patterns were also collected, and principal components of the dietary patterns were identified.

RESULTS

No statistically significant correlations were identified between the analyzed FTO diplotypes and BMI (p = 0.53) or other MetS components (waist circumference p = 0.55; triglycerides p = 0.72; HDL cholesterol p = 0.33; blood glucose p = 0.20; systolic blood pressure p = 0.06; diastolic blood pressure p = 0.21). Stratification by the level of physical activity or adherence to the dietary patterns also did not result in any statistically significant result.

CONCLUSIONS

Some studies have shown that FTO SNPs such as rs1421085, rs1121980, rs8050136, rs9939609, and rs9930506 have an impact on the BMI or other MetS components; nevertheless, this was not replicated in this study of Polish young adult males.

Construction of a label-free fluorescent biosensor for homogeneous detection of m6A eraser FTO in breast cancer tissues

Fat mass and obesity-associated protein (FTO) is a crucial eraser of RNA N6- methyladenosine (m6A) modification, and abnormal FTO expression level is implicated in pathogenesis of numerous cancers. Herein, we demonstrate the construction of a label-free fluorescent biosensor for homogeneous detection of m6A eraser FTO in breast cancer tissues. When FTO is present, it specifically erases the methyl group in m6A, inducing the cleavage of demethylated DNA by endonuclease DpnII and the generation of a single-stranded DNA (ssDNA) with a 3'-hydroxyl group. Subsequently, terminal deoxynucleotidyl transferase (TdT) promotes the incorporation of dTTPs into the ssDNA to obtain a long polythymidine (T) DNA sequence. The resultant long poly (T) DNA sequence can act as a template to trigger hyperbranched strand displacement amplification (HSDA), yielding numerous DNA fragments that may be stained by SYBR Gold to produce an enhanced fluorescence signal. This biosensor processes ultrahigh sensitivity with a detection limit of 1.65 × 10-10 mg/mL (2.6 fM), and it can detect the FTO activity in a single MCF-7 cell. Moreover, this biosensor can screen the FTO inhibitors, evaluate enzyme kinetic parameters, and discriminate the FTO expression levels in the tissues of breast cancer patients and healthy persons.

Palmatine inhibits expression fat mass and obesity associated protein (FTO) and exhibits a curative effect in dextran sulfate sodium (DSS)-induced experimental colitis

BACKGROUND

Ulcerative colitis (UC) is an inflammatory disease whose pathogenesis and mechanisms have not been fully described. The m6A methylation modification is a general mRNA modification in mammalian cells and is closely associated with the onset and progression of inflammatory bowel disease (IBD). Palmatine (PAL) is a biologically active alkaloid with anti-inflammatory and protective effects in animal models of colitis. Accordingly, we examined the role of PAL on colitis by regulating N6-methyladenosine (m6A) methylation.

METHODS

A rat experimental colitis model was established by 5 % dextran sulfate sodium (DSS) in drinking water for seven days, then PAL treatment was administered for seven days. The colonic tissue pathology was assessed using hematoxylin-eosin (HE) and disease activity index (DAI). In in vitro studies, a human, spontaneously immortalized non-cancerous colon mucosal epithelial cell line (NCM460) was exposed to 2 % DSS and treated with PAL and cell viability was assayed using Cell Counting Kit-8 (CCK-8). The levels of tumor necrosis factor α (TNF-α), interleukin (IL)-1β, IL-6, and IL-8 were detected by enzyme-linked immunosorbent assay (ELISA) kits. The level of Zonula occludens-1 (ZO-1) was dectected by immunofluorescence. Transepithelial electrical resistance (TEER) of cells was also assessed. The methyltransferase-like 3 (METTL3), METTL14, AlkB homologate 5 (ALKBH5), and fat mass and obesity-associated protein (FTO) expression levels were assessed by western blotting. The localized expression of m6A was measured by immunofluorescence.

RESULTS

PAL significantly prevented bodyweight loss and shortening of the colon in experimental colitis rats, as well as decreasing the DAI and histological damage scores. Furthermore, PAL inhibited the levels of inflammatory factors (TNF-α, IL-6, IL-8, and IL-1β) in both DSS treated rats and NCM460 cells. In addition, PAL enhanced the expression level of ZO-1, and increased the transepithelial electrical resistance to repaire intestinal barrier dysfunction. Colitis occurred due to decreased m6A levels, and the increased FTO expression led to a colitis phenotype. PAL markedly enhanced the METTL3 and METTL14 expression levels while decreasing ALKBH5 and FTO expression levels.

CONCLUSIONS

The findings demonstrated that PAL improved DSS-induced experimental colitis. This effect was associated with inhibiting FTO expression and regulating m6A methylation.

FTO promotes the progression of retinoblastoma through YTHDF2-dependent N6-methyladenosine modification in E2F3

Early treatment of retinoblastoma (RB) has significantly improved clinical outcomes. N6-methyladenosine (m6A) methylation is crucial for cancer progression. Thus, we investigated the role of FTO-dependent demethylation in RB and its underlying mechanisms. The biological behavior of RB cells was analyzed using cell counting kit-8, colony formation analysis, transwell assay, flow cytometry, and western blot analysis. m6A modification was evaluated using methylated RNA immunoprecipitation and dual-luciferase reporter assays, and E2F3 stability was assessed using Actinomycin D. The roles of FTO and E2F3 were also elucidated in vivo. These results indicated that FTO was highly expressed in RB cells with low m6A levels. FTO knockdown inhibited RB cell growth, migration, invasion, and epithelial-mesenchymal transition and arrested the cell cycle at the G0/G1 phase. Mechanistically, FTO interference promoted m6A methylation of E2F3, which was recognized by YTHDF2, thereby reducing mRNA stability. E2F3 overexpression partially rescued the effects of FTO knockdown on biological behavior. Moreover, FTO knockdown reduced tumor weight, tumor volume, ki67 expression, and tumor cell infiltration by mediating E2F3. Taken together, FTO silencing inhibited the malignant processes of RB by suppressing E2F3 in an m6A-YTHD2-dependent manner. These findings suggest that FTO is a novel therapeutic target for RB.

Demethylases in tumors and the tumor microenvironment: Key modifiers of N6-methyladenosine methylation

RNA methylation modifications are widespread in eukaryotes and prokaryotes, with N6-methyladenosine (m6A) the most common among them. Demethylases, including Fat mass and obesity associated gene (FTO) and AlkB homolog 5 (ALKBH5), are important in maintaining the balance between RNA methylation and demethylation. Recent studies have clearly shown that demethylases affect the biological functions of tumors by regulating their m6A levels. However, their effects are complicated, and even opposite results have appeared in different articles. Here, we summarize the complex regulatory networks of demethylases, including the most important and common pathways, to clarify the role of demethylases in tumors. In addition, we describe the relationships between demethylases and the tumor microenvironment, and introduce their regulatory mechanisms. Finally, we discuss evaluation of demethylases for tumor diagnosis and prognosis, as well as the clinical application of demethylase inhibitors, providing a strong basis for their large-scale clinical application in the future.

Mechanism of Fat Mass and Obesity-Related Gene-Mediated Heme Oxygenase-1 m6A Modification in the Recovery of Neurological Function in Mice with Spinal Cord Injury

OBJECTIVES

This study examined the mechanism of fat mass and obesity-related gene (FTO)-mediated heme oxygenase-1 (HO-1) m6A modification facilitating neurological recovery in spinal cord injury (SCI) mice. FTO/HO-1 was identified as a key regulator of SCI as well as a potential target for treatment of SCI.

METHODS

An SCI mouse was treated with pcDNA3.1-FTO/pcDNA3.1-NC/Dac51. An oxygen/glucose deprivation (OGD) cell model simulated SCI, with cells treated with pcDNA3.1-FTO/si-HO-1/Dac51. Motor function and neurobehavioral evaluation were assessed using the Basso, Beattie, and Bresnahan (BBB) scale and modified neurological severity score (mNSS). Spinal cord pathology and neuronal apoptosis were assessed. Further, FTO/HO-1 mRNA and protein levels, HO-1 mRNA stability, the interaction of YTHDF2 with HO-1 mRNA, neuronal viability/apoptosis, and HO-1 m6A modification were evaluated.

RESULTS

Spinal cord injury mice exhibited reduced BBB, elevated mNSS scores, disorganized spinal cord cells, scattered nuclei, and severe nucleus pyknosis. pcDNA3.1-FTO elevated FTO mRNA, protein expression, and BBB score; reduced the mNSS score of SCI mice; decreased neuronal apoptosis; improved the cell arrangement; and improved nucleus pyknosis in spinal cord tissues. OGD decreased FTO expression. FTO upregulation ameliorated OGD-induced neuronal apoptosis. pcDNA3.1-FTO reduced HO-1 mRNA and protein and HO-1 m6A modification, while increasing HO-1 mRNA stability and FTO in OGD-treated cells. FTO upregulated HO-1 by modulating m6A modification. HO-1 downregulation attenuated the effect of FTO. pcDNA3.1-FTO/Dac51 increased the HO-1 m6A level in mouse spinal cord tissue homogenate, reduced BBB, boosted mNSS scores of SCI mice, aggravated nucleus pyknosis, and increased neuronal apoptosis in spinal cord tissues, confirming that FTO mediated HO-1 m6A modification facilitated neurological recovery in SCI mice.

CONCLUSION

The fat mass and obesity-related gene modulates HO-1 mRNA stability by regulating m6A modification levels, thereby influencing HO-1 expression and promoting neurological recovery in SCI mice.

METTL14 promotes neuroblastoma formation by inhibiting YWHAH via an m6A-YTHDF1-dependent mechanism

Neuroblastoma (NB) is a common childhood tumor with a high incidence worldwide. The regulatory role of RNA N6-methyladenosine (m6A) in gene expression has attracted significant attention, and the impact of methyltransferase-like 14 (METTL14) on tumor progression has been extensively studied in various types of cancer. However, the specific influence of METTL14 on NB remains unexplored. Using data from the Target database, our study revealed significant upregulation of METTL14 expression in high-risk NB patients, with strong correlation with poor prognosis. Furthermore, we identified ETS1 and YY1 as upstream regulators that control the expression of METTL14. In vitro experiments involving the knockdown of METTL14 in NB cells demonstrated significant inhibition of cell proliferation, migration, and invasion. In addition, suppressing METTL14 inhibited NB tumorigenesis in nude mouse models. Through MeRIP-seq and RNA-seq analyses, we further discovered that YWHAH is a downstream target gene of METTL14. Mechanistically, we observed that methylated YWHAH transcripts, particularly those in the 5' UTR, were specifically recognized by the m6A "reader" protein YTHDF1, leading to the degradation of YWHAH mRNA. Moreover, the downregulation of YWHAH expression activated the PI3K/AKT signaling pathway, promoting NB cell activity. Overall, our study provides valuable insights into the oncogenic effects of METTL14 in NB cells, highlighting its role in inhibiting YWHAH expression through an m6A-YTHDF1-dependent mechanism. These findings also suggest the potential utility of a biomarker panel for prognostic prediction in NB patients.

METTL3 recruiting M2-type immunosuppressed macrophages by targeting m6A-SNAIL-CXCL2 axis to promote colorectal cancer pulmonary metastasis

BACKGROUND

The regulatory role of N6-methyladenosine (m6A) modification in the onset and progression of cancer has garnered increasing attention in recent years. However, the specific role of m6A modification in pulmonary metastasis of colorectal cancer remains unclear.

METHODS

This study identified differential m6A gene expression between  primary colorectal cancer and its pulmonary metastases using transcriptome sequencing and immunohistochemistry. We investigated the biological function of METTL3 gene both in vitro and in vivo using assays such as CCK-8, colony formation, wound healing, EDU, transwell, and apoptosis, along with a BALB/c nude mouse model. The regulatory mechanisms of METTL3 in colorectal cancer pulmonary metastasis were studied using methods like methylated RNA immunoprecipitation quantitative reverse transcription PCR, RNA stability analysis, luciferase reporter gene assay, Enzyme-Linked Immunosorbent Assay, and quantitative reverse transcription PCR.

RESULTS

The study revealed high expression of METTL3 and YTHDF1 in the tumors of patients with pulmonary metastasis of colorectal cancer. METTL3 promotes epithelial-mesenchymal transition in colorectal cancer by m6A modification of SNAIL mRNA, where SNAIL enhances the secretion of CXCL2 through the NF-κB pathway. Additionally, colorectal cancer cells expressing METTL3 recruit M2-type macrophages by secreting CXCL2.

CONCLUSION

METTL3 facilitates pulmonary metastasis of colorectal cancer by targeting the m6A-Snail-CXCL2 axis to recruit M2-type immunosuppressive macrophages. This finding offers new research directions and potential therapeutic targets for colorectal cancer treatment.

Ginger inhibits the invasion of ovarian cancer cells SKOV3 through CLDN7, CLDN11 and CD274 m6A methylation modifications

BACKGROUND

Ginger is a common aromatic vegetable with a wide range of functional ingredients and considerable medicinal and nutritional properties. Numerous studies have shown that ginger and its active ingredients have suppressive effects on manifold tumours, including ovarian cancer (OC). However, the molecular mechanism by which ginger inhibits OC is not clear. The aim of this study was to investigate the function and mechanism of ginger in OC.

METHODS

The estimation of n6-methyladenosine (m6A) levels was performed using the m6A RNA Methylation Quantification Kit, and RT-qPCR was used to determine the expression of m6A-related genes and proteins. The m6A methylationome was detected by MeRIP-seq, following analysis of the data. Differential methylation of genes was assessed utilizing RT-qPCR and Western Blotting. The effect of ginger on SKOV3 invasion in ovarian cancer cells was investigated using the wound healing assay and transwell assays.

RESULTS

Ginger significantly reduced the m6A level of OC cells SKOV3. The 3'UTR region is the major site of modification for m6A methylation, and its key molecular activities include Cell Adhesion Molecules, according to meRIP-seq results. Moreover, it was observed that Ginger aids significantly in downregulating the CLDN7, CLDN11 mRNA, and protein expression. The results of wound healing assay and transwell assay showed that ginger significantly inhibited the invasion of OC cells SKOV3.

CONCLUSIONS

Ginger inhibits ovarian cancer cells' SKOV3 invasion by regulating m6A methylation through CLDN7, CLDN11, and CD274.

YTHDC1 promotes the malignant progression of gastric cancer by promoting ROD1 translocation to the nucleus

RNA-binding proteins (RBPs) make vital impacts on tumor progression and are important potential targets for tumor treatment. Previous studies have shown that RBP regulator of differentiation 1 (ROD1), enriched in the nucleus, is abnormally expressed and functions as a splicing factor in tumors; however, the mechanism underlying its involvement in gastric cancer (GC) is unknown. In this study, ROD1 is found to stimulate GC cell proliferation and metastasis and is related to poor patient prognosis. In vitro experiments showed that ROD1 influences GC proliferation and metastasis through modulating the imbalance of the level of the oncogenic gene OIP5 and the tumor suppressor gene GPD1L. Further studies showed that the N6-methyladenosine (m6A) "reader" protein YTHDC1 can interact with ROD1 and regulate the balance of the expression of the downstream molecules OIP5/GPD1L by promoting the nuclear enrichment of ROD1. Therefore, YTHDC1 stimulates GC development and progression through modulating nuclear enrichment of the splicing factor ROD1.

FTO protein regulates the TGF-β signalling pathway through RNA N6-methyladenosine modification to induce unexplained recurrent spontaneous abortion

Recent studies have revealed the involvement of RNA m6A modification in embryonic development; however, the relationship between aberrant RNA m6A modification and unexplained recurrent spontaneous abortion (URSA) remains unclear. In this study, we analysed the level of RNA m6A modification in trophoblasts using dot blot, RNA m6A quantification, and MeRIP assays. By integrating data from the GEO database, RNA-Seq, and MeRIP-Seq, we examined the aberrant expression of m6A methyltransferases and their downstream molecules in chorionic villus (placental) tissues. RNA pull-down, RIP, and electrophoretic mobility shift assay were used to analyse the binding relationship between the YTHDC1 protein and MEG3. Additionally, RNA stability and BrU immunoprecipitation chase assays were utilised to elucidate the regulation of MEG3 stability by YTHDC1. ChIP and DNA pull-down RNA experiments were performed to elucidate the mechanism by which MEG3 targets EZH2 to the TGF-β1 promoter. The results showed that the expression of the m6A demethylase FTO protein was significantly increased in URSA trophoblasts, leading to inhibition of the MEG3 m6A modification and weakening of the stabilising effect of the m6A binding protein YTHDC1 on MEG3. Furthermore, MEG3 was found to bind simultaneously with the EZH2 protein and the TGF-β1 gene promoter, enabling the localisation of EZH2 protein to the TGF-β1 gene promoter and subsequent inhibition of TGF-β1 gene expression. In summary, our findings elucidate the mechanism by which FTO protein regulates the MEG3-TGF-β signalling pathway, thereby suppressing trophoblast invasion and proliferation in URSA trophoblast cells. These findings provide new insights for the treatment of URSA.

Long non-coding RNA GATA6-AS1 is mediated by N6-methyladenosine methylation and inhibits the proliferation and metastasis of gastric cancer

BACKGROUND

Through experimental research on the biological function of GATA6-AS1, it was confirmed that GATA6-AS1 can inhibit the proliferation, invasion, and migration of gastric cancer cells, suggesting that GATA6-AS1 plays a role as an anti-oncogene in the occurrence and development of gastric cancer. Further experiments confirmed that the overexpression of fat mass and obesity-associated protein (FTO) inhibited the expression of GATA6-AS1, thereby promoting the occurrence and development of gastric cancer.

AIM

To investigate the effects of GATA6-AS1 on the proliferation, invasion and migration of gastric cancer cells and its mechanism of action.

METHODS

We used bioinformatics methods to analyze the Cancer Genome Atlas (https://portal.gdc.cancer.gov/. The Cancer Genome Atlas) and download expression data for GATA6-AS1 in gastric cancer tissue and normal tissue. We also constructed a GATA6-AS1 lentivirus overexpression vector which was transfected into gastric cancer cells to investigate its effects on proliferation, migration and invasion, and thereby clarify the expression of GATA6-AS1 in gastric cancer and its biological role in the genesis and development of gastric cancer. Next, we used a database (http://starbase.sysu.edu.cn/starbase2/) to analysis GATA6-AS1 whether by m6A methylation modify regulation and predict the methyltransferases that may methylate GATA6-AS1. Furthermore, RNA immunoprecipitation experiments confirmed that GATA6-AS1 was able to bind to the m6A methylation modification enzyme. These data allowed us to clarify the ability of m6A methylase to influence the action of GATA6-AS1 and its role in the occurrence and development of gastric cancer.

RESULTS

Low expression levels of GATA6-AS1 were detected in gastric cancer. We also determined the effects of GATA6-AS1 overexpression on the biological function of gastric cancer cells. GATA6-AS1 had strong binding ability with the m6A demethylase FTO, which was expressed at high levels in gastric cancer and negatively correlated with the expression of GATA6-AS1. Following transfection with siRNA to knock down the expression of FTO, the expression levels of GATA6-AS1 were up-regulated. Finally, the proliferation, migration and invasion of gastric cancer cells were all inhibited following the knockdown of FTO expression.

CONCLUSION

During the occurrence and development of gastric cancer, the overexpression of FTO may inhibit the expression of GATA6-AS1, thus promoting the proliferation and metastasis of gastric cancer.

FTO-mediated autophagy inhibition promotes non-small cell lung cancer progression by reducing the stability of SESN2 mRNA

The role of fat mass and obesity-associated protein (FTO), an N6-methyladenosine (m6A) demethylase, in non-small cell lung cancer (NSCLC) has recently received widespread attention. However the underlying mechanisms of FTO-mediated autophagy regulation in NSCLC progression remain elusive. In this study, we found that FTO was significantly upregulated in NSCLC, and downregulation of FTO suppressed the growth, invasion and migration of NSCLC cells by inducing autophagy. FTO knockdown resulted in elevated m6A levels in NSCLC cells. Methylated RNA immunoprecipitation sequencing showed that sestrin 2 (SESN2) was involved in m6A regulation during autophagy in NSCLC cells. Interestingly, m6A modifications in exon 9 of SESN2 regulated its stability. FTO deficiency promoted the binding of insulin-like growth factor 2 mRNA-binding protein 1 to SESN2 mRNA, enhancing its stability and elevating its protein expression. FTO inhibited autophagic flux by downregulating SESN2, thereby promoting the growth, invasion and migration of NSCLC cells. Besides, the mechanism by which FTO blocked SESN2-mediated autophagy activation was associated with the AMPK-mTOR signaling pathway. Taken together, these findings uncover an essential role of the FTO-autophagy-SESN2 axis in NSCLC progression.

Emerging roles of the epitranscriptome in parasitic protozoan biology and pathogenesis

RNA modifications (epitranscriptome) - such as N6-methyladenosine (m6A), 5-methylcytosine (m5C), and pseudouridine (Ψ) - modulate RNA processing, stability, interaction, and translation, thereby playing critical roles in the development, replication, virulence, metabolism, and life cycle adaptations of parasitic protozoa. Here, we summarize potential homologs of the major human RNA modification regulatory factors in parasites, outline current knowledge on how RNA modifications affect parasitic protozoa, highlight the regulation of RNA modifications and their crosstalk, and discuss current progress in exploring RNA modifications as potential drug targets. This review contributes to our understanding of epitranscriptomic regulation of parasitic protozoa biology and pathogenesis and provides new perspectives for the treatment of parasitic diseases.

Epigenetic modification in liver fibrosis: Promising therapeutic direction with significant challenges ahead

Liver fibrosis, characterized by scar tissue formation, can ultimately result in liver failure. It's a major cause of morbidity and mortality globally, often associated with chronic liver diseases like hepatitis or alcoholic and non-alcoholic fatty liver diseases. However, current treatment options are limited, highlighting the urgent need for the development of new therapies. As a reversible regulatory mechanism, epigenetic modification is implicated in many biological processes, including liver fibrosis. Exploring the epigenetic mechanisms involved in liver fibrosis could provide valuable insights into developing new treatments for chronic liver diseases, although the current evidence is still controversial. This review provides a comprehensive summary of the regulatory mechanisms and critical targets of epigenetic modifications, including DNA methylation, histone modification, and RNA modification, in liver fibrotic diseases. The potential cooperation of different epigenetic modifications in promoting fibrogenesis was also highlighted. Finally, available agonists or inhibitors regulating these epigenetic mechanisms and their potential application in preventing liver fibrosis were discussed. In summary, elucidating specific druggable epigenetic targets and developing more selective and specific candidate medicines may represent a promising approach with bright prospects for the treatment of chronic liver diseases.

Fat mass and obesity associated protein inhibits neuronal ferroptosis via the FYN/Drp1 axis and alleviate cerebral ischemia/reperfusion injury

OBJECTIVES

FTO is known to be involved in cerebral ischemia/reperfusion (I/R) injury. However, its related specific mechanisms during this condition warrant further investigations. This study aimed at exploring the impacts of FTO and the FYN/DRP1 axis on mitochondrial fission, oxidative stress (OS), and ferroptosis in cerebral I/R injury and the underlying mechanisms.

METHODS

The cerebral I/R models were established in mice via the temporary middle cerebral artery occlusion/reperfusion (tMCAO/R) and hypoxia/reoxygenation models were induced in mouse hippocampal neurons via oxygen-glucose deprivation/reoxygenation (OGD/R). After the gain- and loss-of-function assays, related gene expression was detected, along with the examination of mitochondrial fission, OS- and ferroptosis-related marker levels, neuronal degeneration and cerebral infarction, and cell viability and apoptosis. The binding of FTO to FYN, m6A modification levels of FYN, and the interaction between FYN and Drp1 were evaluated.

RESULTS

FTO was downregulated and FYN was upregulated in tMCAO/R mouse models and OGD/R cell models. FTO overexpression inhibited mitochondrial fission, OS, and ferroptosis to suppress cerebral I/R injury in mice, which was reversed by further overexpressing FYN. FTO overexpression also suppressed mitochondrial fission and ferroptosis to increase cell survival and inhibit cell apoptosis in OGD/R cell models, which was aggravated by additionally inhibiting DRP1. FTO overexpression inhibited FYN expression via the m6A modification to inactive Drp1 signaling, thus reducing mitochondrial fission and ferroptosis and enhancing cell viability in cells.

CONCLUSIONS

FTO overexpression suppressed FYN expression through m6A modification, thereby subduing Drp1 activity and relieving cerebral I/R injury.

N6-methyladenosine modification in ischemic stroke: Functions, regulation, and therapeutic potential

N6-methyladenosine (m6A) modification is the most frequently occurring internal modification in eukaryotic RNAs. By modulating various aspects of the RNA life cycle, it has been implicated in a wide range of pathological and physiological processes associated with human diseases. Ischemic stroke is a major cause of death and disability worldwide with few treatment options and a narrow therapeutic window, and accumulating evidence has indicated the involvement of m6A modifications in the development and progression of this type of stroke. In this review, which provides insights for the prevention and clinical treatment of stroke, we present an overview of the roles played by m6A modification in ischemic stroke from three main perspectives: (1) the association of m6A modification with established risk factors for stroke, including hypertension, diabetes mellitus, hyperlipidemia, obesity, and heart disease; (2) the roles of m6A modification regulators and their functional regulation in the pathophysiological injury mechanisms of stroke, namely oxidative stress, mitochondrial dysfunction, endothelial dysfunction, neuroinflammation, and cell death processes; and (3) the diagnostic and therapeutic potential of m6A regulators in the treatment of stroke.

Imazalil resulted in glucolipid metabolism disturbance and abnormal m6A RNA methylation in the liver of dam and offspring mice

As a fungicide with the characteristics of high effectiveness, internal absorption and broad spectrum, imazalil is widely used to prevent and treat in fruits and vegetables. Here, pregnant C57BL/6 mice were exposed to imazalil at dietary levels of 0, 0.025‰, and 0.25‰ through drinking water during pregnancy and lactation. We then analyzed the phenotype, metabolome, and expression of related genes and proteins in the livers of mice. There was a marked decrease in the body and liver weights of male offspring mice after maternal imazalil exposure, while this effect on the dam and female offspring was slight. Metabolomics analyses revealed that imazalil significantly altered the metabolite composition of liver samples from both dams and offspring. The preliminary results of the analysis indicated that glucolipid metabolism was the pathway most significantly affected by imazalil. We performed a coabundance association analysis of metabolites with significant changes in the pathway of glycolipid metabolism, and IMZ altered the networks of both dams and offspring compared with the network in control mice, especially in male offspring. The hepatic triglyceride, non-esterified fatty acid and glucose levels were increased significantly in the dams but decreased significantly in male offspring after maternal imazalil exposure. Furthermore, the expression levels of genes associated with glycolipid metabolism and m6A RNA methylation were significantly affected by maternal intake of imazalil. Imazalil-induced glucolipid metabolism disturbance was highly correlated with m6A RNA methylation. In conclusion, maternal imazalil exposure resulted in glucolipid metabolism disturbance and abnormal m6A RNA methylation in the livers of dams and offspring mice. We expected that the information acquired in this study will provide novel evidence for understanding the effect of maternal imazalil exposure on potential health risks.

FTO overexpression expedites wound healing and alleviates depression in burn rats through facilitating keratinocyte migration and angiogenesis via mediating TFPI-2 demethylation

Burn injury is a serious traumatic injury that leads to severe physical and psychosocial impairment. Wound healing after burn injury is a substantial challenge in medical community. This study investigated the biological effects of the demethylase fat mass and obesity-associated protein (FTO) on burn injury. FTO protein level in burn skin tissues of patients was measured with Western blot assay. Keratinocytes (HaCaT cells) were given heat stimulation to induce an in vitro burn injury model, and then transfected with overexpression plasmids of FTO (pcDNA-FTO) or small interfering RNA against FTO (si-FTO). Cell proliferation, migration, and angiogenesis in keratinocytes were evaluated with CCK-8, Transwell, and tube formation assays, respectively. Tissue factor pathway inhibitor-2 (TFPI-2) m6A methylation level was detected with MeRIP‑qPCR assay. Then rescue experiments were conducted to explore the effects of FTO/TFPI-2 axis on keratinocyte functions. Lentivirus carrying FTO overexpression plasmids was injected into a burn rat model to detect its effects on wound healing and depressive-like behaviors in burn rats. FTO was downregulated in burn skin and heat-stimulated keratinocytes. FTO prominently augmented proliferation, migration and angiogenesis in heat-stimulated keratinocytes, while FTO knockdown showed the opposite results. FTO inhibited TFPI-2 expression by FTO-mediated m6A methylation modification. TFPI-2 overexpression abrogated FTO mediated enhancement of proliferation, migration and angiogenesis in keratinocytes. Additionally, FTO overexpression accelerated wound healing and improved depressive-like behaviors in burn rat model. FTO prominently augmented proliferation, migration and angiogenesis in heat-stimulated keratinocytes though inhibiting TFPI-2, and then improved wound healing and depressive-like behaviors.

Dephosphorylation Switch DNAzyme-RCA Circuit: A Robust Strategy for the Homogeneous and Reliable Detection of FTO Demethylase

Fat mass and obesity-associated protein (FTO) plays a crucial role in regulating the dynamic modification of N6-methyladenosine (m6A) in eukaryotic mRNA. Sensitive detection of the FTO level and efficient evaluation of the FTO demethylase activity are of great importance to early cancer diagnosis and anticancer drug discovery, which are currently challenged by limited sensitivity/precision and low throughput. Herein, a robust strategy based on the dephosphorylation switch DNAzyme-rolling circle amplification (RCA) circuit, termed DSD-RCA, is developed for highly sensitive detection of FTO and inhibitor screening. Initially, the catalytic activity of DNAzyme is silenced by engineering with an m6A modification in its catalytic core. Only in the presence of target FTO can the methyl group on DNAzyme be eliminated, resulting in the activation of the catalytic activity of DNAzyme and thus cleaving the hairpin substrate to release numerous primers. Different from the conventional methods that use the downstream cleavage primer with the original 3'-hydroxyl end directly as the RCA primer with the problem of high background signal, which should be compensated by additional separation and wash steps in heterogeneous format, our DSD-RCA assay uses the upstream cleavage primer with a 2',3'-cyclic phosphate terminus at the 3'-end serving as an intrinsically blocked 3' end. Only after a dephosphorylation reaction mediated by T4 polynucleotide kinase can the upstream cleavage primers with a resultant 3'-hydroxyl end be extended by RCA. With the high signal-to-noise ratio and homogeneous property, the proposed platform can sensitively detect FTO with a limit of detection of 31.4 pM, and the relative standard deviations (RSDs %) ranging from 0.8 to 2.0% were much lower than the heterogeneous methods. The DSD-RCA method was applied for analyzing FTO in cytoplasmic lysates from different cell lines and tissues of breast cancer patients and further used for screening FTO inhibitors without the need for separation or cleaning, providing an opportunity for achieving high throughput and demonstrating the potential applications of this strategy in disease diagnostics, drug discovery, and biological applications.

Demethylase FTO inhibits the occurrence and development of triple-negative breast cancer by blocking m 6A-dependent miR-17-5p maturation-induced ZBTB4 depletion

Triple-negative breast cancer (TNBC) is a subtype of breast cancer, and its mechanisms of occurrence and development remain unclear. In this study, we aim to investigate the role and molecular mechanisms of the demethylase FTO (fat mass and obesity-associated protein) in TNBC. Through analysis of public databases, we identify that FTO may regulate the maturation of miR-17-5p and subsequently influence the expression of zinc finger and BTB domain-containing protein 4 (ZBTB4), thereby affecting the occurrence and progression of TNBC. We screen for relevant miRNAs and mRNAs from the GEO and TCGA databases and find that the FTO gene may play a crucial role in TNBC. In vitro cell experiments demonstrate that overexpression of FTO can suppress the proliferation, migration, and invasion ability of TNBC cells and can regulate the maturation of miR-17-5p through an m 6A-dependent mechanism. Furthermore, we establish a xenograft nude mouse model and collect clinical samples to further confirm the role and impact of the FTO/miR-17-5p/ZBTB4 regulatory axis in TNBC. Our findings unveil the potential role of FTO and its underlying molecular mechanisms in TNBC, providing new perspectives and strategies for the research and treatment of TNBC.

RNA m6A methylation regulators in liver cancer

Liver cancer is one of the most common cancers in the world and a primary cause of cancer-related death. In recent years, despite the great development of diagnostic methods and targeted therapies for liver cancer, the incidence and mortality of liver cancer are still on the rise. As a universal post-transcriptional modification, N6-methyladenosine (m6A) modification accomplishes a dynamic and reversible m6A modification process, which is executed by three types of regulators, methyltransferases (called writers), demethylases (called erasers) and m6A-binding proteins (called readers). Many studies have shown that m6A RNA methylation has an important impact on RNA metabolism, whereas its regulation exception is bound up with the occurrence of human malignant tumors. Aberrant methylation of m6A RNA and the expression of related regulatory factors may be of the essence in the pathogenesis and progression of liver cancer, yet the precise molecular mechanism remains unclear. In this paper, we review the current research situations of m6A methylation in liver cancer. Among the rest, we detail the mechanism by which methyltransferases, demethylases and m6A binding proteins regulate the occurrence and development of liver cancer by modifying mRNA. As well as the potential effect of m6A regulators in hepatocarcinogenesis and progression. New ideas and approaches will be given to the prevention and treatment of liver cancer through the following relevant research results.

Minor alleles of FTO rs9939609 and rs17817449 polymorphisms confer a higher risk of type 2 diabetes mellitus and dyslipidemia, but not coronary artery disease in a Chinese Han population

Background

Relationships of the polymorphisms in fat mass and obesity-associated gene (FTO) and peroxisome proliferator-activated receptor delta gene (PPARD) with metabolic-related diseases remain to be clarified.

Methods

One thousand three hundred and eighty-one subjects were enrolled. Metabolic-related diseases including obesity, dyslipidemia, hyperhomocysteinemia, hyperuricemia, hypertension, type 2 diabetes mellitus (T2DM) and coronary artery disease (CAD) were defined based on diagnostic criteria. FTO rs9939609 and rs17817449, and PPARD rs2016520 and rs2267668 polymorphisms were genotyped by using polymerase chain reaction-restricted fragment length polymorphism method.

Results

Patients with T2DM or dyslipidemia had a higher frequency of AA, AT or AA + AT genotypes as well as A allele of FTO rs9939609 polymorphism than those free of T2DM or dyslipidemia (P ≤ 0.04 for all). Patients with T2DM or dyslipidemia had a higher frequency of GG, GT or GG + GT genotypes as well as G allele of FTO rs17817449 polymorphism than those free of T2DM or dyslipidemia (P ≤ 0.03 for all). Multivariate logistic regression analyses showed that FTO rs9939609 and rs17817449 polymorphisms were independently associated with T2DM as well as dyslipidemia after adjustment for age, sex, smoking and other metabolic diseases. FTO rs9939609 and rs17817449 polymorphisms were not associated with obesity, hyperhomocysteinemia, hyperuricemia, hypertension and CAD. Obese or T2DM carriers of the AA or AT genotype of the FTO rs9939609 polymorphism had a higher prevalence of dyslipidemia compared to non-obese or non-T2DM carriers of the AA or AT genotype (P = 0.03 for both). Among the carriers of GG or GT genotype of the FTO rs17817449 polymorphism, the prevalence of dyslipidemia in obese patients was higher than that in non-obese subjects (P < 0.01). PPARD rs2016520 and rs2267668 polymorphisms were not correlated with any of the metabolic-related diseases in the study population.

Conclusion

Minor alleles of FTO rs9939609 and rs17817449 polymorphisms confer a higher risk of T2DM and dyslipidemia, and the risk is further increased among obese individuals. PPARD rs2016520 and rs2267668 polymorphisms are not associated with metabolic-related diseases.

FTO Sensitizes Oral Squamous Cell Carcinoma to Ferroptosis via Suppressing ACSL3 and GPX4

Ferroptosis is a newly established form of regulated cell death characterized by intracellular lipid peroxidation and iron accumulation that may be a promising cancer treatment strategy. However, the function and therapeutic value of ferroptosis in oral squamous cell carcinoma (OSCC) remain inadequately understood. In the present study, we investigated the biological role of the fat mass and obesity-associated gene (FTO) in ferroptosis in the context of OSCC. We found that OSCC had greater potential for ferroptosis, and FTO is associated with ferroptosis. Furthermore, higher FTO expression sensitized OSCC cells to ferroptosis in vitro and in vivo. Mechanistically, FTO suppressed the expression of anti-ferroptotic factors, acyl-CoA synthetase long-chain family member 3 (ACSL3) and glutathione peroxidase 4 (GPX4), by demethylating the m6A modification on the mRNA of ACSL3 and GPX4 and decreasing their stability. Taken together, our findings revealed that FTO promotes ferroptosis through ACSL3 and GPX4 regulation. Thus, ferroptosis activation in OSCC with high FTO levels may serve as a potential therapeutic target.

FTO facilitates cancer metastasis by modifying the m6A level of FAP to induce integrin/FAK signaling in non-small cell lung cancer

BACKGROUND

Emerging evidence suggests the critical roles of N6-methyladenosine (m6A) RNA modification in tumorigenesis and tumor progression. However, the role of m6A in non-small cell lung cancer (NSCLC) is still unclear. This study aimed to explore the role of the m6A demethylase fat mass and obesity-associated protein (FTO) in the tumor metastasis of NSCLC.

METHODS

A human m6A epitranscriptomic microarray analysis was used to identify downstream targets of FTO. Quantitative real-time PCR (qRT‒PCR) and western blotting were employed to evaluate the expression levels of FTO and FAP in NSCLC cell lines and tissues. Gain-of-function and loss-of-function assays were conducted in vivo and in vitro to assess the effects of FTO and FAP on NSCLC metastasis. M6A-RNA immunoprecipitation (MeRIP), RNA immunoprecipitation (RIP), luciferase reporter assays, and RNA stability assays were used to explore the mechanism of FTO action. Co-immunoprecipitation (co-IP) assays were used to determine the mechanism of FAP in NSCLC metastasis.

RESULTS

FTO was upregulated and predicted poor prognosis in patients with NSCLC. FTO promoted cell migration and invasion in NSCLC, and the FAK inhibitor defactinib (VS6063) suppressed NSCLC metastasis induced by overexpression of FTO. Mechanistically, FTO facilitated NSCLC metastasis by modifying the m6A level of FAP in a YTHDF2-dependent manner. Moreover, FTO-mediated metastasis formation depended on the interactions between FAP and integrin family members, which further activated the FAK signaling.

CONCLUSION

Our current findings provided valuable insights into the role of FTO-mediated m6A demethylation modification in NSCLC metastasis. FTO was identified as a contributor to NSCLC metastasis through the activation of the FAP/integrin/FAK signaling, which may be a potential therapeutic target for NSCLC. Video Abstract.

The emerging roles of N6-methyladenosine RNA modifications in thyroid cancer

Thyroid cancer (TC) is the most predominant malignancy of the endocrine system, with steadily growing occurrence and morbidity worldwide. Although diagnostic and therapeutic methods have been rapidly developed in recent years, the underlying molecular mechanisms in the pathogenesis of TC remain enigmatic. The N6-methyladenosine(m6A) RNA modification is designed to impact RNA metabolism and further gene regulation. This process is intricately regulated by a variety of regulators, such as methylases and demethylases. Aberrant m6A regulators expression is related to the occurrence and development of TC and play an important role in drug resistance. This review comprehensively analyzes the effect of m6A methylation on TC progression and the potential clinical value of m6A regulators as prognostic markers and therapeutic targets in this disease.

The functional roles of m6A modification in prostate cancer

Prostate cancer (PCa) is the most prevalent malignancy of the male genitourinary system, and its etiology suggests that genetics is an essential risk factor for its development and progression, while exogenous factors may have an significant impact on this risk. Initial diagnosis of advanced PCa is relatively frequent, and androgen deprivation therapy (ADT) is the predominant standard of care for PCa and the basis for various novel combination therapy regimens, and is often required throughout the patient's subsequent treatment. Although diagnostic modalities and treatment options are evolving, some patients suffer from complications, including biochemical relapse, metastasis and treatment resistance. Mechanisms of PCa pathogenesis and progression have been the focus of research. N6-methyladenosine (m6A) is an RNA modification involved in cell physiology and tumor metabolism. It has been observed to affect the evolution of diverse cancers through the regulation of gene expression. Genes associated with m6A are prominent in PCa and are involved in multiple aspects of desmoresistant PCa occurrence, progression, PCa bone metastasis (BM), and treatment resistance. Here, we explore the role of m6A modifications in promoting PCa.

Role of m6A modification in regulating the PI3K/AKT signaling pathway in cancer

The phosphoinositide 3-kinase (PI3K)/AKT signaling pathway plays a crucial role in the pathogenesis of cancer. The dysregulation of this pathway has been linked to the development and initiation of various types of cancer. Recently, epigenetic modifications, particularly N6-methyladenosine (m6A), have been recognized as essential contributors to mRNA-related biological processes and translation. The abnormal expression of m6A modification enzymes has been associated with oncogenesis, tumor progression, and drug resistance. Here, we review the role of m6A modification in regulating the PI3K/AKT pathway in cancer and its implications in the development of novel strategies for cancer treatment.

N6-methyladenosine (m6A) in cancer therapeutic resistance: Potential mechanisms and clinical implications

Cancer therapy resistance (CTR) is the development of cancer resistance to multiple therapeutic strategies, which severely affects clinical response and leads to cancer progression, recurrence, and metastasis. N6-methyladenosine (m6A) has been identified as the most common, abundant, and conserved internal transcriptional alterations of RNA modifications, regulating RNA splicing, translation, stabilization, degradation, and gene expression, and is involved in the development and progression of a variety of diseases, including cancer. Recent studies have shown that m6A modifications play a critical role in both cancer development and progression, especially in reversing CTR. Although m6A modifications have great potential in CTR, the specific molecular mechanisms are not fully elucidated. In this review, we summarize the potential molecular mechanisms of m6A modification in CTR. In addition, we update recent advances in natural products from Traditional Chinese Medicines (TCM) and small-molecule lead compounds targeting m6A modifications, and discuss the great potential and clinical implications of these inhibitors targeting m6A regulators and combinations with other therapies to improve clinical efficacy and overcome CTR.

Crosstalk between m6A modification and alternative splicing during cancer progression

Background N6-methyladenosine (m6A), the most prevalent internal mRNA modification in eukaryotes, is added by m6A methyltransferases, removed by m6A demethylases and recognised by m6A-binding proteins. This modification significantly influences carious facets of RNA metabolism and plays a pivotal role in cellular and physiological processes. Main body Pre-mRNA alternative splicing, a process that generates multiple splice isoforms from multi-exon genes, contributes significantly to the protein diversity in mammals. Moreover, the presence of crosstalk between m6A modification and alternative splicing, with m6A modifications on pre-mRNAs exerting regulatory control, has been established. The m6A modification modulates alternative splicing patterns by recruiting specific RNA-binding proteins (RBPs) that regulate alternative splicing or by directly influencing the interaction between RBPs and their target RNAs. Conversely, alternative splicing can impact the deposition or recognition of m6A modification on mRNAs. The integration of m6A modifications has expanded the scope of therapeutic strategies for cancer treatment, while alternative splicing offers novel insights into the mechanistic role of m6A methylation in cancer initiation and progression. Conclusion This review aims to highlight the biological functions of alternative splicing of m6A modification machinery and its implications in tumourigenesis. Furthermore, we discuss the clinical relevance of understanding m6A-dependent alternative splicing in tumour therapies.

The role of N6-methyladenosine modification in rodent models of neuropathic pain: from the mechanism to therapeutic potential

Neuropathic pain (NP) is a common chronic pain condition resulted from lesions or diseases of somatosensory nervous system, but the pathogenesis remains unclear. A growing body of evidence supports the relationship between pathogenesis and N6-methyladenosine (m6A) modifications of RNA. However, studies on the role of m6A modifications in NP are still at an early stage. Elucidating different etiologies is important for understanding the specific pathogenesis of NP. This article provides a comprehensive review on the role of m6A methylation modifications including methyltransferases ("writers"), demethylases ("erasers"), and m6A binding proteins ("readers") in NP models. Further analysis of the pathogenic mechanism relationship between m6A and NP provided novel theoretical and practical significance for clinical treatment of NP.

Overexpression of FTO inhibits excessive proliferation and promotes the apoptosis of human glomerular mesangial cells by alleviating FOXO6 m6A modification via YTHDF3-dependent mechanisms

Background: N6-methyladenosine (m6A) is a prevalent post-transcriptional modification presented in messenger RNA (mRNA) of eukaryotic organisms. Chronic glomerulonephritis (CGN) is characterised by excessive proliferation and insufficient apoptosis of human glomerular mesangial cells (HGMCs) but its underlying pathogenesis remains undefined. Moreover, the role of m6A in CGN is poorly understood. Methods: The total level of m6A modification was detected using the m6A quantification assay (Colorimetric). Cell proliferation was assessed by EdU cell proliferation assay, and cell apoptosis was detected by flow cytometry. RNA sequencing was performed to screen the downstream target of fat mass and obesity-associated protein (FTO). MeRIP-qPCR was conducted to detect the m6A level of forkhead box o6 (FOXO6) in HGMCs. RIP assay was utilized to indicate the targeting relationship between YTH domain family 3 (YTHDF3) and FOXO6. Actinomycin D assay was used to investigate the stability of FOXO6 in HGMCs. Results: The study found that the expression of FTO was significantly reduced in lipopolysaccharide (LPS)-induced HGMCs and renal biopsy samples of patients with CGN. Moreover, FTO overexpression and knockdown could regulate the proliferation and apoptosis of HGMCs. Furthermore, RNA sequencing and cellular experiments revealed FOXO6 as a downstream target of FTO in regulating the proliferation and apoptosis of HGMCs. Mechanistically, FTO overexpression decreases the level of FOXO6 m6A modification and reduces the stability of FOXO6 mRNA in a YTHDF3-dependent manner. Additionally, the decreased expression of FOXO6 inhibits the PI3K/AKT signaling pathway, thereby inhibiting the proliferation and promoting apoptosis of HGMCs. Conclusion: This study offers insights into the mechanism through which FTO regulates the proliferation and apoptosis of HGMCs by mediating m6A modification of FOXO6 mRNA. These findings also suggest FTO as a potential diagnostic marker and therapeutic target for CGN.

Rna M6 a Methylation Regulates Glycolysis of Beige Fat and Contributes to Systemic Metabolic Homeostasis

N6-methyladenosine (m6 A) modification has been implicated in the progression of obesity and metabolic diseases. However, its impact on beige fat biology is not well understood. Here, via m6 A-sequencing and RNA-sequencing, this work reports that upon beige adipocytes activation, glycolytic genes undergo major events of m6 A modification and transcriptional activation. Genetic ablation of m6 A writer Mettl3 in fat tissues reveals that Mettl3 deficiency in mature beige adipocytes leads to suppressed glycolytic capability and thermogenesis, as well as reduced preadipocytes proliferation via glycolytic product lactate. In addition, specific modulation of Mettl3 in beige fat via AAV delivery demonstrates consistently Mettl3's role in glucose metabolism, thermogenesis, and beige fat hyperplasia. Mechanistically, Mettl3 and m6 A reader Igf2bp2 control mRNA stability of key glycolytic genes in beige adipocytes. Overall, these findings highlight the significance of m6 A on fat biology and systemic energy homeostasis.

RNA m6A modification in prostate cancer: A new weapon for its diagnosis and therapy

Prostate cancer (PCa) is the most common malignant tumor and the second leading cause of cancer-related mortality in men worldwide. Despite significant advances in PCa therapy, the underlying molecular mechanisms have yet to be fully elucidated. Recently, epigenetic modification has emerged as a key player in tumor progression, and RNA-based N6-methyladenosine (m6A) epigenetic modification was found to be crucial. This review summarizes comprehensive state-of-art mechanisms underlying m6A modification, its implication in the pathogenesis, and advancement of PCa in protein-coding and non-coding RNA contexts, its relevance to PCa immunotherapy, and the ongoing clinical trials for PCa treatment. This review presents potential m6A-based targets and paves a new avenue for diagnosing and treating PCa, providing new guidelines for future related research through a systematic review of previous results.

RNA methylations in depression, from pathological mechanism to therapeutic potential

Depression is caused by a variety of factors such as genetic factors, biological factors, and psychosocial factors, and the pathogenesis is complex. RNA methylations and related downstream signaling pathways influence a variety of biological mechanisms, including cell differentiation, tumorigenesis, sex determination, and stress response. In this work, we searched the PubMed, Web of Science, National Library of Science and Technology (NSTL), and ScienceDirect Online (SDOL) databases to summarize the biological roles of RNA methylations and their impact on the pathological mechanisms of depression. RNA methylations play a key role in the development of many diseases, and current research shows that RNA methylations are also closely linked to depression. RNA methylations in depression mainly involve "writers" (mediating the methylation modification process of RNAs), "erasers" (mediating the demethylation modification process of RNA methylation). Fat Mass and Obesity Associated (FTO) influences the development of depression by increasing body mass index (BMI), decreases the dopamine level, inhibits the adrenoceptor beta 2 (ADRB2)-c-Myc-sirt1 pathway, results in the m6A/m6Am dysregulation in brain, and may be involved in the pathogenesis of depression. The study of RNA methylations in depression has further deepened our understanding of the pathogenesis and development process of depression, provides new perspectives for the study of the pathological mechanism of depression, and provides new targets for the prevention and treatment of this disease.

RNA modification: mechanisms and therapeutic targets

RNA modifications are dynamic and reversible chemical modifications on substrate RNA that are regulated by specific modifying enzymes. They play important roles in the regulation of many biological processes in various diseases, such as the development of cancer and other diseases. With the help of advanced sequencing technologies, the role of RNA modifications has caught increasing attention in human diseases in scientific research. In this review, we briefly summarized the basic mechanisms of several common RNA modifications, including m6A, m5C, m1A, m7G, Ψ, A-to-I editing and ac4C. Importantly, we discussed their potential functions in human diseases, including cancer, neurological disorders, cardiovascular diseases, metabolic diseases, genetic and developmental diseases, as well as immune disorders. Through the "writing-erasing-reading" mechanisms, RNA modifications regulate the stability, translation, and localization of pivotal disease-related mRNAs to manipulate disease development. Moreover, we also highlighted in this review all currently available RNA-modifier-targeting small molecular inhibitors or activators, most of which are designed against m6A-related enzymes, such as METTL3, FTO and ALKBH5. This review provides clues for potential clinical therapy as well as future study directions in the RNA modification field. More in-depth studies on RNA modifications, their roles in human diseases and further development of their inhibitors or activators are needed for a thorough understanding of epitranscriptomics as well as diagnosis, treatment, and prognosis of human diseases.

An Association between Decreased Small Intestinal RNA Modification and Disturbed Glucagon-like Peptide-1 Secretion under High-Fat Diet Stress

Unhealthy diets rich in fats and/or sugar are considered as the major external cause of the obesity epidemic, which is often accompanied by a significant decrease in gut hormone glucagon-like peptide-1 (GLP1) levels. Numerous studies have demonstrated notable contributions of the gut microbiota in this process. Nevertheless, the underlying mechanism still needs further investigation. The role of epigenetic modifications in gene expression and metabolism has been well demonstrated, with m6A methylation on RNAs being the most prevalent modification throughout their metabolism. In the present study, we found that the expressions of small intestinal Gcg and Pc3, two key genes regulating GLP1 expression, were significantly downregulated in obese mice, associated with reduced GLP1 level. Immunohistochemistry analysis indicated that a high-fat diet slightly increased the density of enteroendocrine L cells in the small intestine, implying that decreased GLP1 levels were not caused by the changes in L cell intensity. Instead, the small intestinal m6A level as well as the expression of known "writers", mettl3/14 and wtap, were found to be positively correlated with the expression of Gcg and Pc3. Fecal microbiota transplantation with feces from normal and obese mice daily to antibiotic-treated mice revealed that dysbiosis in diet-induced obesity was sufficient to reduce serum GLP1, small intestinal m6A level, and intestinal expressions of Gcg, Pc3, and writer genes (mettl3/14, wtap). However, as the most direct and universal methyl donor, the production of fecal S-adenosylmethionine was neither affected by the different dietary patterns nor their shaped microbiota. These results suggested that microbial modulation of the epitranscriptome may be involved in regulating GLP1 expression, and highlighted epitranscriptomic modifications as an additional level of interaction between diet and individual health.

N6-methyladenosine RNA modification: an emerging molecule in type 2 diabetes metabolism

Type 2 diabetes (T2D) is a metabolic disease with an increasing rate of incidence worldwide. Despite the considerable progress in the prevention and intervention, T2D and its complications cannot be reversed easily after diagnosis, thereby necessitating an in-depth investigation of the pathophysiology. In recent years, the role of epigenetics has been increasingly demonstrated in the disease, of which N6-methyladenosine (m6A) is one of the most common post-transcriptional modifications. Interestingly, patients with T2D show a low m6A abundance. Thus, a comprehensive analysis and understanding of this phenomenon would improve our understanding of the pathophysiology, as well as the search for new biomarkers and therapeutic approaches for T2D. In this review, we systematically introduced the metabolic roles of m6A modification in organs, the metabolic signaling pathways involved, and the effects of clinical drugs on T2D.

Metabolo-epigenetic interplay provides targeted nutritional interventions in chronic diseases and ageing

Epigenetic modifications are chemical modifications that affect gene expression without altering DNA sequences. In particular, epigenetic chemical modifications can occur on histone proteins -mainly acetylation, methylation-, and on DNA and RNA molecules -mainly methylation-. Additional mechanisms, such as RNA-mediated regulation of gene expression and determinants of the genomic architecture can also affect gene expression. Importantly, depending on the cellular context and environment, epigenetic processes can drive developmental programs as well as functional plasticity. However, misbalanced epigenetic regulation can result in disease, particularly in the context of metabolic diseases, cancer, and ageing. Non-communicable chronic diseases (NCCD) and ageing share common features including altered metabolism, systemic meta-inflammation, dysfunctional immune system responses, and oxidative stress, among others. In this scenario, unbalanced diets, such as high sugar and high saturated fatty acids consumption, together with sedentary habits, are risk factors implicated in the development of NCCD and premature ageing. The nutritional and metabolic status of individuals interact with epigenetics at different levels. Thus, it is crucial to understand how we can modulate epigenetic marks through both lifestyle habits and targeted clinical interventions -including fasting mimicking diets, nutraceuticals, and bioactive compounds- which will contribute to restore the metabolic homeostasis in NCCD. Here, we first describe key metabolites from cellular metabolic pathways used as substrates to "write" the epigenetic marks; and cofactors that modulate the activity of the epigenetic enzymes; then, we briefly show how metabolic and epigenetic imbalances may result in disease; and, finally, we show several examples of nutritional interventions - diet based interventions, bioactive compounds, and nutraceuticals- and exercise to counteract epigenetic alterations.

FTO promotes cervical cancer cell proliferation, colony formation, migration and invasion via the regulation of the BMP4/Hippo/YAP1/TAZ pathway

Cervical cancer is the fourth most common malignancy tumor worldwide with high incidence and mortality. Accumulating evidence indicated that through an m6A-dependent or m6A-independent mechanism, fat mass and obesity associated gene (FTO) exhibits the tumor-promoting and suppressive roles of FTO involved in various cancers, including cervical cancer. This study aims to verify the biological function and potential mechanisms of FTO in cervical cancer cell proliferation, colony formation, migration, and invasion in vitro as well as tumor growth in vivo. Herein, we confirmed that knockdown of FTO inhibits cell proliferation, colony formation, migration, and invasion of cervical cancer cells in vitro via cell counting kit-8 (CCK8) assay, colony formation assay, and transwell migration and invasion assay. The demethylase activity of FTO is required for cell proliferation, colony formation, migration, and invasion of cervical cancer cells in vitro. RNA sequencing, online database analysis, and western blotting revealed that FTO regulated the BMP4/Hippo/YAP1/TAZ pathway. In addition, FTO upregulates the expression of BMP4 in an m6A-dependent manner and binds to the N-terminal of BMP4 to form a dimer at the C-terminal in cervical cancer cells through protein-protein interaction. We further discovered that BMP4 treatment promoted cell proliferation, colony formation, migration, and invasion of cervical cancer cells, and rescue experiments validated that BMP4 treatment reversed the inhibition of FTO knockdown on the Hippo/YAP1/TAZ pathway and the progression of cervical cancer cells in vitro. Notably, the knockdown of FTO significantly suppressed xenograft tumor growth and the protein level of BMP4 in vivo. Collectively, our results demonstrate that the FTO promotes cervical cancer progression in vitro and in vivo via the regulation of the BMP4/Hippo/YAP1/TAZ pathway, suggesting that FTO acts as an oncogenic molecule and the FTO/BMP4 Hippo/YAP1/TAZ axis may serve as valuable targets for cervical cancer treatment.

The Causal Effect of Dietary Composition on the Risk of Breast Cancer: A Mendelian Randomization Study

Breast cancer has become the most common malignancy among women, posing a severe health risk to women worldwide and creating a heavy social burden. Based on current observational studies, the dietary factor may have a causal relationship with breast cancer. Therefore, exploring how dietary composition affects breast cancer incidence will provide nutrition strategies for clinicians and women. We performed a two-sample Mendelian randomization (MR) analysis to find the causal effect of four kinds of relative macronutrient intake (protein, carbohydrate, sugar, and fat) on the risk of breast cancer and its subtypes [Luminal A, Luminal B, Luminal B HER2-negative, HER2-positive, Triple-negative, Estrogen receptor (ER) positive, and ER-negative breast cancer]. The Mendelian randomization pleiotropy residual sum and outlier (MR-PRESSO) test, MR-Egger intercept test, Cochran's Q statistic, funnel plot, and leave-one-out (Loo) analysis were all used in a sensitivity analysis to test the robustness of MR. Genetically, a higher relative protein intake was found as a protective factor for Luminal A and overall breast cancer, which was inconsistent with recent findings. A higher relative sugar intake could genetically promote the risk of Luminal B and HER2-positive breast cancer. Conclusions: A higher protein proportion in diet genetically reduces the risk of breast cancer, while higher relative sugar intake does the opposite.