bims-rimeca Biomed News
on RNA methylation in cancer
Issue of 2023–03–12
25 papers selected by
Sk Ramiz Islam, Saha Institute of Nuclear Physics



  1. Apoptosis. 2023 Mar 10.
      N6-methyladenosine (m6A) is emerging as an essential regulator in the progression of myocardial ischemia reperfusion (I/R) injury. However, the in-depth functions and mechanisms for m6A are still unclear. This work aimed to explore the potential functions and mechanisms for myocardial I/R injury. In this study, m6A methyltransferase WTAP and m6A modification level elevated in the hypoxia/reoxygenation (H/R) induced rat cardiomyocytes (H9C2) and I/R injury rat model. Bio-functional cellular experiments demonstrated that knockdown of WTAP remarkably released the proliferation and reduced the apoptosis and inflammatory cytokines induced by H/R. Moreover, exercise training alleviated WTAP level in exercise-trained rats. Mechanistically, methylated RNA immunoprecipitation sequencing (MeRIP-Seq) revealed that a remarkable m6A modification site was found in the 3'-UTR of FOXO3a mRNA. Moreover, WTAP triggered the installation of m6A modification on FOXO3a mRNA through m6A reader YTHDF1, thereby enhancing the stability of FOXO3a mRNA. Collectively, WTAP/YTHDF1/m6A/FOXO3a axis regulates the myocardial I/R injury progression, which provides new insights for the treatment of myocardial injury.
    Keywords:  FOXO3a; Myocardial ischemia reperfusion injury; N6-methyladenosine; WTAP
    DOI:  https://doi.org/10.1007/s10495-023-01818-4
  2. Heliyon. 2023 Mar;9(3): e13721
      Recent studies have shown that N6-methyladenosine (m6A) methylation, one of the most prevalent epigenetic modifications, is involved in diabetes mellitus. However, whether m6A regulates diabetic vascular endothelium injury is still elusive. Present research aimed to investigate the regulation and mechanism of m6A on vascular endothelium injury. Upregulation of METTL3 was observed in the high glucose (HG)-induced human umbilical vein endothelial cells (HUVECs), following with the upregulation of m6A methylation level. Functionally, METTL3 silencing repressed the apoptosis and recovered the proliferation of HUVECs disposed by HG. Moreover, HG exposure upregulated the expression of suppressor of cytokine signaling3 (SOCS3). Mechanistically, METTL3 targeted the m6A site on SOCS3 mRNA, which positively regulated the mRNA stability of SOCS3. In conclusion, METTL3 silencing attenuated the HG-induced vascular endothelium cells injury via promoting SOCS3 stability. In conclusion, this research expands the understanding of m6A on vasculopathy in diabetes mellitus and provides a potential strategy for the protection of vascular endothelial injury.
    Keywords:  HUVECs; High glucose; METTL3; N6-methyladenosine; SOCS3
    DOI:  https://doi.org/10.1016/j.heliyon.2023.e13721
  3. Cancer Lett. 2023 Mar 08. pii: S0304-3835(23)00073-3. [Epub ahead of print] 216122
      Lenvatinib is emerging as the first-line therapeutic option for advanced hepatocellular carcinoma (HCC), but drug resistance remains a major hurdle for its long-term therapy efficiency in clinic. N6-methyladenosine (m6A) is the most abundant mRNA modification. Here, we aimed to investigate the modulatory effects and underlying mechanisms of m6A in lenvatinib resistance in HCC. Our data revealed that m6A mRNA modification was significantly upregulated in the HCC lenvatinib resistance (HCC-LR) cells compared to parental cells. Methyltransferase-like 3 (METTL3) was the most significantly upregulated protein among the m6A regulators. Either genetic or pharmacological inhibition of m6A methylation through METTL3 deactivation in primary resistant cell line MHCC97H and acquired resistant Huh7-LR cells decreased cell proliferation and increased cell apoptosis upon lenvatinib treatment in vitro and in vivo. In addition, the specific METTL3 inhibitor STM2457 improved tumor response to lenvatinib in multiple mouse HCC models, including subcutaneous, orthotopic and hydrodynamic models. The MeRIP-seq results showed that epidermal growth factor receptor (EGFR) was a downstream target of METTL3. EGFR overexpression abrogated the METTL3 knocked down-induced cell growth arrest upon lenvatinib treatment in HCC-LR cells. Thus, we concluded that targeting METTL3 using specific inhibitor STM2457 improved the sensitivity to lenvatinib in vitro and in vivo, indicating that METTL3 may be a potential therapeutic target to overcome lenvatinib resistance in HCC.
    Keywords:  EGFR; Hepatocellular carcinoma; Lenvatinib resistance; STM2457
    DOI:  https://doi.org/10.1016/j.canlet.2023.216122
  4. Shock. 2023 Mar 07.
       ABSTRACT: Sepsis-induced cardiomyopathy (SIC) is one of the most common complications of infection-induced sepsis. An imbalance in inflammatory mediators is the main factor leading to SIC. N6-methyladenosine (m6A) is closely related to the occurrence and development of sepsis. m6A reader YTH Domain Containing 1 (YTHDC1) is an m6A N6-methyladenosine recognition protein. However, the role of YTHDC1 in SIC remains unclear. Herein, we demonstrated that YTHDC1-shRNA inhibits inflammation, reduces inflammatory mediators, and improves cardiac function in a lipopolysaccharide (LPS)-induced SIC mouse model. Based on the Gene Expression Omnibus (GEO) database analysis, serine protease inhibitor A3N (SERPINA3N) is a differential gene of SIC. Further, RNA immunoprecipitation (RIP) indicated that SERPINA3N mRNA can bind to YTHDC1, which regulates the expression of SERPINA3N. SERPINA3N-siRNA reduced LPS-induced inflammation of cardiac myocytes. In conclusion, the m6A reader YTHDC1 regulates SERPINA3N mRNA expression to mediate the levels of inflammation in SIC. Such findings add to the relationship between m6A reader YTHDC1 and SIC, providing a new research avenue for the therapeutic mechanism of SIC.
    DOI:  https://doi.org/10.1097/SHK.0000000000002106
  5. PLoS Biol. 2023 Mar;21(3): e3002017
      Alzheimer's disease (AD) is a heterogeneous disease with complex clinicopathological characteristics. To date, the role of m6A RNA methylation in monocyte-derived macrophages involved in the progression of AD is unknown. In our study, we found that methyltransferase-like 3 (METTL3) deficiency in monocyte-derived macrophages improved cognitive function in an amyloid beta (Aβ)-induced AD mouse model. The mechanistic study showed that that METTL3 ablation attenuated the m6A modification in DNA methyltransferase 3A (Dnmt3a) mRNAs and consequently impaired YTH N6-methyladenosine RNA binding protein 1 (YTHDF1)-mediated translation of DNMT3A. We identified that DNMT3A bound to the promoter region of alpha-tubulin acetyltransferase 1 (Atat1) and maintained its expression. METTL3 depletion resulted in the down-regulation of ATAT1, reduced acetylation of α-tubulin and subsequently enhanced migration of monocyte-derived macrophages and Aβ clearance, which led to the alleviated symptoms of AD. Collectively, our findings demonstrate that m6A methylation could be a promising target for the treatment of AD in the future.
    DOI:  https://doi.org/10.1371/journal.pbio.3002017
  6. J Diabetes. 2023 Mar 09.
       OBJECTIVE: To clarify the expression of N6-methyladenosine (m6 A) modulators involved in the pathogenesis of type 2 diabetes mellitus (T2DM). We further explored the association of serum insulin-like growth factor 2 mRNA-binding proteins 3 (IGF2BP3) levels and odds of T2DM in a high-risk population.
    METHODS: The gene expression data set GSE25724 was obtained from the Gene Expression Omnibus, and a cluster heatmap was generated by using the R package ComplexHeatmap. Differential expression analysis for 13 m6 A RNA methylation regulators between nondiabetic controls and T2DM subjects was performed using an unpaired t test. A cross-sectional design, including 393 subjects (131 patients with newly diagnosed T2DM, 131 age- and sex-matched subjects with prediabetes, and 131 healthy controls), was carried out. The associations between serum IGF2BP3 concentrations and T2DM were modeled by restricted cubic spline and logistic regression models.
    RESULTS: Two upregulated (IGF2BP2 and IGF2BP3) and 5 downregulated (methyltransferase-like 3 [METTL3], alkylation repair homolog protein 1 [ALKBH1], YTH domain family 2 [YTHDF2], YTHDF3, and heterogeneous nuclear ribonucleoprotein [HNRNPC]) m6 A-related genes were found in islet samples of T2DM patients. A U-shaped association existed between serum IGF2BP3 levels and odds of T2DM according to cubic natural spline analysis models, after adjustment for body mass index, waist circumference, diastolic blood pressure, total cholesterol, and triglyeride. Multivariate logistic regression showed that progressively higher odds of T2DM were observed when serum IGF2BP3 levels were below 0.62 ng/mL (odds ratio 3.03 [95% confidence interval 1.23-7.47]) in model 4.
    CONCLUSION: Seven significantly altered m6 A RNA methylation genes were identified in T2DM. There was a U-shaped association between serum IGF2BP3 levels and odds of T2DM in the general Chinese adult population. This study provides important evidence for further examination of the role of m6 A RNA methylation, especially serum IGF2BP3 in T2DM risk assessment.
    Keywords:  N6-methyladenosine (m6A) RNA methylation; gene expression omnibus; insulin-like growth factor 2 mRNA-binding protein (IGF2BP)3; type 2 diabetes mellitus
    DOI:  https://doi.org/10.1111/1753-0407.13378
  7. Biomark Res. 2023 Mar 10. 11(1): 30
       BACKGROUND: Although t (8;21) is in fact considered a good risk acute myeloid leukemia (AML), only 60% of the patients live beyond 5 years after diagnosis. Studies have shown that RNA demethylase ALKBH5 promotes leukemogenesis. However, the molecular mechanism and clinical significance of ALKBH5 in t (8;21) AML have not been elucidated.
    METHODS: The expression of ALKBH5 was assessed in t (8;21) AML patients via qRT-PCR and western blot. The proliferative activity of these cells was examined through CCK-8 or colony-forming assays, while flow cytometry approaches were used to examine apoptotic cell rates. The in vivo role of ALKBH5 promoting leukemogenesis was assessed using t (8;21) murine model, CDX, and PDX models. RNA sequencing, m6A RNA methylation assay, RNA immunoprecipitation, and luciferase reporter assay were used to explore the molecular mechanism of ALKBH5 in t (8;21) AML.
    RESULTS: ALKBH5 is highly expressed in t (8;21) AML patients. Silencing ALKBH5 suppresses the proliferation and promotes the apoptosis of patient-derived AML cells and Kasumi-1 cells. With integrated transcriptome analysis and wet-lab confirmation, we found that ITPA is a functionally important target of ALKBH5. Mechanistically, ALKBH5 demethylates ITPA mRNA and increases its mRNA stability, leading to enhanced ITPA expression. Furthermore, transcription factor TCF15, specifically expressed in leukemia stem/initiating cells (LSCs/LICs), is responsible for the dysregulated expression of ALKBH5 in t (8;21) AML.
    CONCLUSION: Our work uncovers a critical function for the TCF15/ALKBH5/ITPA axis and provides insights into the vital roles of m6A methylation in t (8;21) AML.
    Keywords:  ALKBH5; Leukemia stem/initiating cells; Transcription factors; m6A methylation; t (8;21) acute myeloid leukemia
    DOI:  https://doi.org/10.1186/s40364-023-00464-x
  8. J Oncol. 2023 ;2023 4738586
      N6-methyladenosine (m6A) is an abundant eukaryotic mRNA modification involved in regulating the formation and metastasis of nonsmall cell lung cancer (NSCLC). We collected clinical NSCLC tissue and paracarcinoma tissue. Then methyltransferase-like 14 (METTL14), pleomorphic adenoma gene like-2 (PLAGL2), and β-catenin expressions were assessed using quantitative real-time PCR and western blot. PLAGL2, and β-catenin (nuclear) expressions were increased in NSCLC tissues. Cell proliferation, migration, invasion, and death were examined. PLAGL2 could activate β-catenin signaling to affect cell proliferation and migration abilities. RNA immunoprecipitation assay was operated to identify m6A modification levels of PLAGL2 after knockdown and overexpression of METTL14. PLAGL2 was regulated by METTL14-mediated m6A modification. Knockdown of METTL14 repressed cell proliferation, migration, and invasion, and promoted cell death. Interestingly, these effects were reversed when PLAGL2 was overexpressed. Finally, tumor formation in nude mice was performed to verify the role of the METTL14/PLAGL2/β-catenin signaling axis. Tumor formation in nude mice demonstrated METTL14/PLAGL2/β-catenin axis promoted NSCLC development in vivo. In brief, METTL14 promoted NSCLC development by increasing m6A methylation of PLAGL2 to activate β-catenin signaling. Our research provided essential clues for in-depth comprehension of the mechanism of NSCLC occurrence and development and also provided the basis for NSCLC treatment.
    DOI:  https://doi.org/10.1155/2023/4738586
  9. Int Wound J. 2023 Mar 10.
      Keloids are formed due to abnormal hyperplasia of the skin connective tissue. We explored the relationship between N6-methyladenosine (m6A)-related genes and keloids. The transcriptomic datasets (GSE44270 and GSE185309) of keloid and normal skin tissues samples were obtained from the Gene Expression Omnibus database. We constructed the m6A landscape and verified the corresponding genes using immunohistochemistry. We extracted hub genes for unsupervised clustering analysis using protein-protein interaction (PPI) network; gene ontology enrichment analysis was performed to determine the biological processes or functions affected by the differentially expressed genes (DEGs). We performed immune infiltration analysis to determine the relationship between keloids and the immune microenvironment using single-sample gene set enrichment analysis and CIBERSORT. Differential expression of several m6A genes was observed between the two groups; insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3) was significantly upregulated in keloid patients. PPI analysis elucidated six genes with significant differences between the two keloid sample groups. Enrichment analysis revealed that the DEGs were mainly enriched in cell division, proliferation, and metabolism. Moreover, significant differences in immunity-related pathways were observed. Therefore, the results of this study will provide a reference for the elucidation of the pathogenesis and therapeutic targets of keloids.
    Keywords:  GEO; enrichment analysis; immune infiltration; keloid; m6A
    DOI:  https://doi.org/10.1111/iwj.14144
  10. Biol Proced Online. 2023 Mar 04. 25(1): 6
       BACKGROUND: YTHDF2 is one of important readers of N6-methyladenosine (m6A) modification on RNA. Growing evidence implicates that YTHDF2 takes an indispensable part in the regulation of tumorigenesis and metastasis in different cancers, but its biological functions and underlying mechanisms remain elusive in gastric cancer (GC).
    AIM: To investigate the clinical relevance and biological function of YTHDF2 in GC.
    RESULTS: Compared with matched normal stomach tissues, YTHDF2 expression was markedly decreased in gastric cancer tissues. The expression level of YTHDF2 was inversely associated with gastric cancer patients' tumor size, AJCC classification and prognosis. Functionally, YTHDF2 reduction facilitated gastric cancer cell growth and migration in vitro and in vivo, whereas YTHDF2 overexpression exhibited opposite phenotypes. Mechanistically, YTHDF2 enhanced expression of PPP2CA, the catalytic subunit of PP2A (Protein phosphatase 2A), in an m6A-independent manner, and silencing of PPP2CA antagonized the anti-tumor effects caused by overexpression of YTHDF2 in GC cells.
    CONCLUSION: These findings demonstrate that YTHDF2 is down-regulated in GC and its down-regulation promotes GC progression via a possible mechanism involving PPP2CA expression, suggesting that YTHDF2 may be a hopeful biomarker for diagnosis and an unrevealed treatment target for GC.
    Keywords:  Gastric Cancer; PPP2CA; Progression; YTHDF2
    DOI:  https://doi.org/10.1186/s12575-023-00195-1
  11. Am J Physiol Cell Physiol. 2023 Mar 06.
       BACKGROUND: To explore the specific roles of a crucial N6-methyladenosine (m6A) methyltransferase, methyltransferase-like 14 (METTL14), in FLSs activation of rheumatoid arthritis (RA).
    METHODS: RA rat model was induced by administering intraperitoneally collagen antibody alcohol. Primary fibroblast-like synoviocytes (FLSs) were isolated from joint synovium tissues from rats. shRNA transfection tools were used to downregulated METTL14 expression in vivo and vitro. The injury of joint synovium showed by HE staining. The cell apoptosis of FLSs was determined by flow cytometry. The levels of IL-6, IL-18 and CXCL10 in serum and culture supernatants were measured by ELISA kits. The expressions of LIM and SH3 domain protein 1(LASP1), p-SRC/SRC, and p-AKT/AKT in FLSs and joint synovium tissues were determined by western blots.
    RESULTS: The expression of METTL14 was greatly induced in the synovium tissues of RA rat compared with normal control rat. Compared with sh-NC treated FLSs, METTL14 knockdown significantly increased cell apoptosis, inhibited cell migration and invasion, and suppressed the production of IL-6, IL-18 and CXCL10 induced by TNF-a. METTL14 Silencing suppresses the expression of LASP1 and the activation of Src/AKT axis induce by TNF-a in FLSs. METTL14 improves the mRNA stability of LASP1 through m6A modification. In contrast, these were reversed by LASP1 overexpression. Moreover, METTL14 silencing clearly alleviates FLSs activation and inflammation in a RA rat model.
    CONCLUSION: These results suggested that METTL14 promote FLSs activation and related inflammatory response via the LASP1/SRC/AKT signaling pathway and identified METTL14 as a potential target for treating RA.
    Keywords:  METTL14; fibroblast-like synoviocytes
    DOI:  https://doi.org/10.1152/ajpcell.00575.2022
  12. Front Mol Neurosci. 2023 ;16 1102147
      N6-methyladenosine (m6A) is the most abundant internal RNA modification in eukaryotic cells, which participates in the functional regulation of various biological processes. It regulates the expression of targeted genes by affecting RNA translocation, alternative splicing, maturation, stability, and degradation. As recent evidence shows, of all organs, brain has the highest abundance of m6A methylation of RNAs, which indicates its regulating role in central nervous system (CNS) development and the remodeling of the cerebrovascular system. Recent studies have shown that altered m6A levels are crucial in the aging process and the onset and progression of age-related diseases. Considering that the incidence of cerebrovascular and degenerative neurologic diseases increase with aging, the importance of m6A in neurological manifestations cannot be ignored. In this manuscript, we focus on the role of m6A methylation in aging and neurological manifestations, hoping to provide a new direction for the molecular mechanism and novel therapeutic targets.
    Keywords:  6-methyladenosine; CNS diseases; RNA methylation; m6A; neurovascular unit
    DOI:  https://doi.org/10.3389/fnmol.2023.1102147
  13. Diabetes Res Clin Pract. 2023 Mar 04. pii: S0168-8227(23)00082-7. [Epub ahead of print] 110607
       AIMS: N6-methyladenosine (m6A) in mRNA is involved in glucose metabolism. Our goal is to investigate the relationship of glucose metabolism, m6A and YTH domain-containing protein 1 (YTHDC1), a binding protein to m6A, in the development of type 2 diabetes (T2D).
    METHODS: HPLC-MS/MS and qRT-PCR were used to quantify m6A and YTHDC1 levels in white blood cells from patients with T2D and healthy individuals. MIP-CreERT and tamoxifen treatment were used to create β-cell Ythdc1 knockout mice (βKO). m6A sequencing and RNA sequencing were performed in wildtype/βKO islets and MIN6 cells to identify the differential genes.
    RESULTS: In T2D patients, both of m6A and YTHDC1 levels were reduced and associated with fasting glucose. Deletion of Ythdc1 resulted in glucose intolerance and diabetes due to decreased insulin secretion, even though β-cell mass in βKO mice was comparable to wildtype mice. Moreover, Ythdc1 was shown to bind to SRSF3 (serine/arginine-rich splicing factor 3) and CPSF6 (cleavage and polyadenylation specific factor 6) in β-cells.
    CONCLUSIONS: Our data suggested that YTHDC1 may regulate mRNA splicing and export by interacting with SRSF3 and CPSF6 to modulate glucose metabolism via regulating insulin secretion, implying YTHDC1 might be a novel potential target for lowing glucose.
    Keywords:  YTHDC1; glucose metabolism; m(6)A; type 2 diabetes; β-cell
    DOI:  https://doi.org/10.1016/j.diabres.2023.110607
  14. iScience. 2023 Mar 17. 26(3): 106215
      The clinical application of anthracyclines such as doxorubicin (DOX) is limited due to their cardiotoxicity. N6-methyladenosine (m6A) plays an essential role in numerous biological processes. However, the roles of m6A and m6A demethylase ALKBH5 in DOX-induced cardiotoxicity (DIC) remain unclear. In this research, DIC models were constructed using Alkbh5-knockout (KO), Alkbh5-knockin (KI), and Alkbh5-myocardial-specific knockout (ALKBH5flox/flox, αMyHC-Cre) mice. Cardiac function and DOX-mediated signal transduction were investigated. As a result, both Alkbh5 whole-body KO and myocardial-specific KO mice had increased mortality, decreased cardiac function, and aggravated DIC injury with severe myocardial mitochondrial damage. Conversely, ALKBH5 overexpression alleviated DOX-mediated mitochondrial injury, increased survival, and improved myocardial function. Mechanistically, ALKBH5 regulated the expression of Rasal3 in an m6A-dependent manner through posttranscriptional mRNA regulation and reduced Rasal3 mRNA stability, thus activating RAS3, inhibiting apoptosis through the RAS/RAF/ERK signaling pathway, and alleviating DIC injury. These findings indicate the potential therapeutic effect of ALKBH5 on DIC.
    Keywords:  Biological sciences; Molecular biology; Pathophysiology
    DOI:  https://doi.org/10.1016/j.isci.2023.106215
  15. Front Neurosci. 2023 ;17 1069640
      Recent studies have suggested a role for N6-methyladenosine (m6A) modification in neurological diseases. Hypothermia, a commonly used treatment for traumatic brain injury, plays a neuroprotective role by altering m6A modifications. In this study, methylated RNA immunoprecipitation sequencing (MeRIP-Seq) was applied to conduct a genome-wide analysis of RNA m6A methylation in the rat hippocampus of Sham and traumatic brain injury (TBI) groups. In addition, we identified the expression of mRNA in the rat hippocampus after TBI with hypothermia treatment. Compared with the Sham group, the sequencing results of the TBI group showed that 951 different m6A peaks and 1226 differentially expressed mRNAs were found. We performed cross-linking analysis of the data of the two groups. The result showed that 92 hyper-methylated genes were upregulated, 13 hyper-methylated genes were downregulated, 25 hypo-methylated genes were upregulated, and 10 hypo-methylated genes were downregulated. Moreover, a total of 758 differential peaks were identified between TBI and hypothermia treatment groups. Among these differential peaks, 173 peaks were altered by TBI and reversed by hypothermia treatment, including Plat, Pdcd5, Rnd3, Sirt1, Plaur, Runx1, Ccr1, Marveld1, Lmnb2, and Chd7. We found that hypothermia treatment transformed some aspects of the TBI-induced m6A methylation landscape of the rat hippocampus.
    Keywords:  epigenetic modification; hypothermia; m6A methylation; rat hippocampus; traumatic brain injury
    DOI:  https://doi.org/10.3389/fnins.2023.1069640
  16. Plant Cell. 2023 Mar 09. pii: koad070. [Epub ahead of print]
      Addition of N6-methyladenosine (m6A), the most prevalent internal mRNA modification in eukaryotes, is catalyzed by an evolutionarily conserved m6A methyltransferase complex. In the model plant Arabidopsis thaliana, the m6A methyltransferase complex is composed of two core methyltransferases, mRNA adenosine methylase (MTA) and MTB, and several accessory subunits such as FK506-BINDING PROTEIN 12 KD INTERACTING PROTEIN 37KD (FIP37), VIRILIZER (VIR) and HAKAI. It is yet largely unknown whether these accessory subunits influence the functions of MTA and MTB. Herein, I reveal that FIP37 and VIR are indispensable for stabilizing the methyltransferases MTA and MTB, thus functioning as key subunits to maintain the functionality of the m6A methyltransferase complex. Furthermore, VIR affects FIP37 and HAKAI protein accumulation, while MTA and MTB mutually influence each other. In contrast, HAKAI has little effect on protein abundance or localization of MTA, MTB and FIP37. These findings uncover unique functional interdependence at the post-translational level among individual components in the Arabidopsis m6A methyltransferase complex, suggesting that maintenance of protein homeostasis among various subunits of the m6A methyltransferase complex is essential for maintaining the protein stoichiometry required for the proper function of the m6A methyltransferase complex in m6A deposition in plants.
    DOI:  https://doi.org/10.1093/plcell/koad070
  17. Front Oncol. 2023 ;13 1087644
       Introduction: Colorectal cancer (CRC) remains a significant cause of cancer related mortality. Fat mass and obesity-associated protein (FTO) is a m6A mRNA demethylase that plays an oncogenic role in various malignancies. In this study we evaluated the role of FTO in CRC tumorigenesis.
    Methods: Cell proliferation assays were conducted in 6 CRC cell lines with the FTO inhibitor CS1 (50-3200 nM) (± 5-FU 5-80 mM) and after lentivirus mediated FTO knockdown. Cell cycle and apoptosis assays were conducted in HCT116 cells (24 h and 48 h, 290 nM CS1). Western blot and m6A dot plot assays were performed to assess CS1 inhibition of cell cycle proteins and FTO demethylase activity. Migration and invasion assays of shFTO cells and CS1 treated cells were performed. An in vivo heterotopic model of HCT116 cells treated with CS1 or with FTO knockdown cells was performed. RNA-seq was performed on shFTO cells to assess which molecular and metabolic pathways were impacted. RT-PCR was conducted on select genes down-regulated by FTO knockdown.
    Results: We found that the FTO inhibitor, CS1 suppressed CRC cell proliferation in 6 colorectal cancer cell lines and in the 5-Fluorouracil resistant cell line (HCT116-5FUR). CS1 induced cell cycle arrest in the G2/M phase by down regulation of CDC25C and promoted apoptosis of HCT116 cells. CS1 suppressed in vivo tumor growth in the HCT116 heterotopic model (p< 0.05). Lentivirus knockdown of FTO in HCT116 cells (shFTO) mitigated in vivo tumor proliferation and in vitro demethylase activity, cell growth, migration and invasion compared to shScr controls (p< 0.01). RNA-seq of shFTO cells compared to shScr demonstrated down-regulation of pathways related to oxidative phosphorylation, MYC and Akt/ mTOR signaling pathways.
    Discussion: Further work exploring the targeted pathways will elucidate precise downstream mechanisms that can potentially translate these findings to clinical trials.
    Keywords:  FTO; FTO inhibitor; RNA-seq; colorectal cancer; signaling pathways
    DOI:  https://doi.org/10.3389/fonc.2023.1087644
  18. Elife. 2023 Mar 09. pii: e82703. [Epub ahead of print]12
      Skeletal muscle stem cells (also known as satellite cells, SCs) are essential for muscle regeneration and the regenerative activities of SCs are intrinsically governed by gene regulatory mechanisms but the post-transcriptional regulation in SCs remains largely unknown. N(6)-methyladenosine (m6A) modification of RNAs is the most pervasive and highly conserved RNA modification in eukaryotic cells and exerts powerful impact on almost all aspects of mRNA processing which is mainly endowed by its binding with m6A reader proteins. Here in this study, we investigate the previously uncharacterized regulatory roles of YTHDC1, a m6A reader in mouse SCs. Our results demonstrate YTHDC1 is an essential regulator of SC activation and proliferation upon acute injury induced muscle regeneration. The induction of YTHDC1 is indispensable for SC activation and proliferation thus inducible YTHDC1 depletion almost abolishes SC regenerative capacity. Mechanistically, transcriptome-wide profiling using LACE-seq in both SCs and mouse C2C12 myoblasts identifies m6A mediated binding targets of YTHDC1. Next, splicing analysis defines splicing mRNA targets of m6A-YTHDC1. Furthermore, nuclear export analysis also leads to identification of potential mRNA export targets of m6A-YTHDC1 in SCs and C2C12 myoblasts and interestingly some mRNAs can be regulated at both splicing and export levels. Lastly, we map YTHDC1 interacting protein partners in myoblasts and unveil a myriad of factors governing mRNA splicing, nuclear export and transcription, among which hnRNPG appears to be a bona fide interacting partner of YTHDC1. Altogether, our findings uncover YTHDC1 as an essential factor controlling SC regenerative ability through multi-faceted gene regulatory mechanisms in mouse myoblast cells.
    Keywords:  cell biology; mouse; regenerative medicine; stem cells
    DOI:  https://doi.org/10.7554/eLife.82703
  19. Environ Pollut. 2023 Mar 04. pii: S0269-7491(23)00395-0. [Epub ahead of print] 121393
      Studies have shown that Bisphenol F (BPF) as an emerging bisphenol pollutant also has caused many hazards to the reproductive systems of humans and animals. However, its specific mechanism is still unclear. The mouse TM3 Leydig cell model was used to explore the mechanism of BPF-induced reproductive toxicity in this study. The results showed BPF (0, 20, 40 and 80 μM) exposure for 72 h increased cell apoptosis. Correspondingly, BPF increased the expression of P53 and BAX, and decreased the expression of BCL2. Moreover, BPF significantly increased the intracellular ROS level in TM3 cells, and significantly decreased oxidative stress-related molecule Nrf2. BPF decreased the expression of FTO and YTHDF2, and increased the total cellular m6A level. ChIP results showed that AhR transcriptionally regulated FTO. Differential expression of FTO revealed that FTO reduced the apoptosis rate of BPF-exposed TM3 cells and increased the expression of Nrf2, MeRIP confirmed that overexpression of FTO reduced the m6A of Nrf2 mRNA. After differential expression of YTHDF2, it was found that YTHDF2 enhanced the stability of Nrf2, and RIP assay showed that YTHDF2 was bound to Nrf2 mRNA. Nrf2 agonist enhanced the protective effect of FTO on TM3 cells exposure to BPF. Our study is the first to propose that AhR transcriptionally regulated FTO, and then FTO regulated Nrf2 in a m6A-modified manner through YTHDF2, thereby affecting apoptosis in BPF-exposed TM3 cells to induce reproductive damage. It provides new insights into the importance of FTO-YTHDF2-Nrf2 signaling pathway in BPF-induced reproductive toxicity and provided a new idea for the prevention of male reproductive injury.
    Keywords:  Bisphenol F; FTO gene; Nrf2; Reproductive toxicity; YTHDF2
    DOI:  https://doi.org/10.1016/j.envpol.2023.121393
  20. Am J Cancer Res. 2023 ;13(2): 538-568
      Although N7-methylguanosine (m7G) is one of the most frequent RNA modifications, it has received little attention. Adrenocortical carcinoma (ACC) is a highly malignant and easily metastatic tumor, eagerly needing for novel therapeutic strategy. Herein, a novel m7G risk signature (METTL1, NCBP1, NUDT1 and NUDT5) was constructed using the Lasso regression analysis. It possessed highly prognostic value and could improve the predictive accuracy and clinical making-decision benefit of traditional prognostic model. Its prognostic value was also successfully validated in GSE19750 cohort. Through CIBERSORT, ESTIMATE, ssGSEA and GSEA analyzes, high-m7G risk score was found to be closely associated with increased enrichment of glycolysis and suppression of anti-cancer immune response. Therapeutic correlation of m7G risk signature was also investigated using tumor mutation burden, the expressions of immune checkpoints, TIDE score, IMvigor 210 cohort and TCGA cohort. m7G risk score was a potential biomarker for predicting the efficacy of ICBs and mitotane. Furthermore, we explored the biofunctions of METTL1 in ACC cells through a series of experimentations. Overexpression of METTL1 stimulated the proliferation, migration and invasion of H295R and SW13 cells. Immunofluorescence assays revealed that the infiltrating levels of CD8+ T cells was lower and that of macrophages was higher in clinical ACC samples with high METTL1 expression compared to that in low expression ones. Silencing METTL1 could significantly inhibited tumor growth in mouse xenograft model. Western blot assays showed that METTL1 positively regulated the expression of glycolysis rate-limiting enzyme HK1. Finally, miR-885-5p and CEBPB were predicted as the upstream regulators of METTL1 through data mining of the public databases. In conclusions, m7G regulatory genes well represented by METTL1 profoundly affected the prognosis, tumor immune, therapeutic outcomes, and malignant progression of ACC.
    Keywords:  METTL1; N7-methylguanosine; adrenocortical carcinoma; prognosis; risk signature
  21. Medicine (Baltimore). 2023 Mar 10. 102(10): e33133
      N6-methyladenosine (m6A) RNA methylation, as a reversible epigenetic modification of mammalian mRNA, holds a critical role in multiple biological processes. m6A modification in Long non-coding RNAs (lncRNAs) has increasingly attracted more attention in recent years, especially in diabetics, with or without metabolic syndrome. We investigated via m6A-sequencing and RNA-sequencing the differentially expressed m6A modification lncRNAs by high glucose and TNF-α induced endothelial cell dysfunction in human umbilical vein endothelial cells. Additionally, gene ontology and kyoto encyclopedia of genes and genomes analyses were performed to analyze the biological functions and pathways for the target of mRNAs. Lastly, a competing endogenous RNA network was established to further reveal a regulatory relationship between lncRNAs, miRNAs and mRNAs. A total of 754 differentially m6A-methylated lncRNAs were identified, including 168 up-regulated lncRNAs and 266 down-regulated lncRNAs. Then, 119 significantly different lncRNAs were screened out, of which 60 hypermethylated lncRNAs and 59 hypomethylated lncRNAs. Moreover, 122 differentially expressed lncRNAs were filtered, containing 14 up-regulated mRNAs and 18 down-regulated lncRNAs. Gene ontology and kyoto encyclopedia of genes and genomes analyses analyses revealed these targets were mainly associated with metabolic process, HIF-1 signaling pathway, and other biological processes. The competing endogenous RNA network revealed the regulatory relationship between lncRNAs, miRNAs and mRNAs, providing potential targets for the treatment and prevention of diabetic endothelial cell dysfunction. This comprehensive analysis for lncRNAs m6A modification in high glucose and TNF-α-induced human umbilical vein endothelial cells not only demonstrated the understanding of characteristics of endothelial cell dysfunction, but also provided the new targets for the clinical treatment of diabetes. Private information from individuals will not be published. This systematic review also does not involve endangering participant rights. Ethical approval will not be required. The results may be published in a peer-reviewed journal or disseminated at relevant conferences.
    DOI:  https://doi.org/10.1097/MD.0000000000033133
  22. Cell Commun Signal. 2023 Mar 09. 21(1): 53
      Gene expression and posttranscriptional regulation can be strongly influenced by epigenetic modifications. N6-methyladenosine, the most extensive RNA modification, has been revealed to participate in many human diseases. Recently, the role of RNA epigenetic modifications in the pathophysiological mechanism of female reproductive diseases has been intensively studied. RNA m6A modification is involved in oogenesis, embryonic growth, and foetal development, as well as preeclampsia, miscarriage, endometriosis and adenomyosis, polycystic ovary syndrome, premature ovarian failure, and common gynaecological tumours such as cervical cancer, endometrial cancer, and ovarian cancer. In this review, we provide a summary of the research results of m6A on the female reproductive biology and pathophysiology in recent years and aim to discuss future research directions and clinical applications of m6A-related targets. Hopefully, this review will add to our understanding of the cellular mechanisms, diagnostic biomarkers, and underlying therapeutic strategies of female reproductive system diseases. Video Abstract.
    Keywords:  Abortion; Endometriosis; Epigenetic modification; Gynaecological cancer; Preeclampsia; Reproductive disease; m6A methylation
    DOI:  https://doi.org/10.1186/s12964-023-01078-4
  23. Diagnostics (Basel). 2023 Feb 21. pii: 823. [Epub ahead of print]13(5):
      To date, only a single transcriptome-wide m6A sequencing study of clear cell renal cell carcinoma (ccRCC) has been reported, with no validation so far. Herein, by TCGA analysis of the KIRC cohort (n = 530 ccRCC; n = 72 normal), an external expression validation of 35 preidentified m6A targets was performed. Further in-depth expression stratification enabled assessment of m6A-driven key targets. Overall survival (OS) analysis and gene set enrichment analyses (GSEA) were conducted to assess their clinical and functional impact on ccRCC. In the hyper-up cluster significant upregulation was confirmed for NDUFA4L2, NXPH4, SAA1, and PLOD2 (40%) and in the hypo-up cluster for FCHSD1 (10%). Significant downregulation was observed for UMOD, ANK3, and CNTFR (27.3%) in the hypo-down cluster and for CHDH (25%) in the hyper-down cluster. In-depth expression stratification showed consistent dysregulation in ccRCC only for 11.67%: NDUFA4L2, NXPH4, and UMOD (NNU-panel). Patients with strong NNU panel dysregulation had significantly poorer OS (p = 0.0075). GSEA identified 13 associated and significantly upregulated gene sets (all p-values < 0.5; FDR < 0.25). External validation of the only available m6A sequencing in ccRCC consistently reduced dysregulated m6A-driven targets on the NNU panel with highly significant effects on OS. Epitranscriptomics are a promising target for developing novel therapies and for identifying prognostic markers for daily clinical practice.
    Keywords:  METTL3; MeRip-seq; N6-methyladenosine (m6A); epitranscriptomics; kidney cancer; m6A-reader; uromodulin
    DOI:  https://doi.org/10.3390/diagnostics13050823
  24. Genes Immun. 2023 Mar 08.
      Triple-negative breast cancer (TNBC) is a heterogeneous and aggressive disease with poor prognosis. Acetylation modifications affect a great number of biological processes of malignant tumors. The current study aims at revealing the role of acetylation-related mechanism in TNBC progression. Methyltransferase like-3 (METTL3) was found to be downregulated in TNBC cells via quantitative polymerase chain reaction (qPCR) and western blot analyses. Co-Immunoprecipitation (Co-IP) and GST pulldown assays revealed the interaction between acetyl-CoA acetyltransferase 1 (ACAT1) and METTL3. Through further immunoprecipitation (IP) assay, we determined that ACAT1 stabilizes METTL3 protein via inhibiting the degradation of ubiquitin-proteasome. Functionally, ACAT1 inhibits TNBC cell migration and invasion. Moreover, nuclear receptor subfamily 2 group F member 6 (NR2F6) regulates ACAT1 expression at transcriptional level. Finally, we demonstrated that NR2F6/ACAT/METTL3 axis suppresses the migration and invasion of TNBC cells via METTL3. In conclusion, NR2F6 transcriptionally activates ACAT1 and promotes the suppressive effects of ACAT1-mediated METTL3 acetylation on TNBC cell migration and invasion.
    DOI:  https://doi.org/10.1038/s41435-023-00202-1
  25. J Neurosci. 2023 Mar 09. pii: JN-RM-2321-22. [Epub ahead of print]
      RNA N4-acetylcytidine (ac4C) modification is increasingly recognized as an important layer of gene regulation; however, the involvement of ac4C in pain regulation has not been studied. Here, we report that N-acetyltransferase 10 protein (NAT10, the only known ac4C "writer") contributes to the induction and development of neuropathic pain in an ac4C-dependent manner. Peripheral nerve injury increases the levels of NAT10 expression and overall ac4C in injured dorsal root ganglia (DRGs). This upregulation is triggered by the activation of USF1, a transcription factor that binds to the Nat10 promoter. Knockdown or genetic deletion of NAT10 in the DRG abolishes the gain of ac4C sites in Syt9 mRNA and the augmentation of SYT9 protein, resulting in a marked antinociceptive effect in nerve-injured male mice. Conversely, mimicking NAT10 upregulation in the absence of injury evokes the elevation of Syt9 ac4C and SYT9 protein and induces the genesis of neuropathic-pain-like behaviors. These findings demonstrate that USF1-governed NAT10 regulates neuropathic pain by targeting Syt9 ac4C in peripheral nociceptive sensory neurons. Our findings establish NAT10 as a critical endogenous initiator of nociceptive behavior and a promising new target for treating neuropathic pain.SIGNIFICANCE STATEMENT:The cytidine N4-acetylcytidine (ac4C), a new epigenetic RNA modification, is crucial for the translation and stability of mRNA, but its role for chronic pain remains unclear. Here we demonstrate that NAT10 acts as ac4C N-acetyltransferase and plays an important role in the development and maintenance of neuropathic pain. NAT10 was upregulated via the activation of the transcription factor USF1 in the injured DRG after peripheral nerve injury. Since pharmacological or genetic deleting NAT10 in the DRG attenuated the nerve injury-induced nociceptive hypersensitivities partially through suppressing Syt9 mRNA ac4C and stabilizing SYT9 protein level, NAT10 may serve as an effective and novel therapeutic target for neuropathic pain.
    DOI:  https://doi.org/10.1523/JNEUROSCI.2321-22.2023