bims-rimeca 2023-06-04 papers

bims-rimeca

Biomed News

on RNA methylation in cancer

Issue of 2023–06–04
28 papers selected by
Sk Ramiz Islam, Saha Institute of Nuclear Physics

TROP2 translation mediated by dual m6A/m7G RNA modifications promotes bladder cancer development.
The YTHDC1/GLUT3/RNF183 axis forms a positive feedback loop that modulates glucose metabolism and bladder cancer progression.
FLOT1, stabilized by WTAP/IGF2BP2 mediated N6-methyladenosine modification, predicts poor prognosis and promotes growth and invasion in gliomas.
The m6A Reader YTHDF1 Promotes Lung Carcinoma Progression via Regulating Ferritin Mediate Ferroptosis in an m6A-Dependent Manner.
m6A Regulator-mediated RNA Methylation Modulates Immune Microenvironment of Hepatitis B Virus-related Acute Liver Failure.
IGF2BP3/HIF1A/YAP signaling plays a role in driving acute-on-chronic liver failure through activating hepatocyte reprogramming.
METTL3 achieves lipopolysaccharide-induced myocardial injury via m6A-dependent stabilization of Myh3 mRNA.
Mettl3-m6A-Creb1 forms an intrinsic regulatory axis in maintaining iNKT cell pool and functional differentiation.
The role of m6A methylation in therapy resistance in cancer.
METTL3-mediated ALDH m6 A methylation regulates the malignant behavior of BMI1+ HNSCC stem cells.
N6-methyladenosine modification of CENPF mRNA facilitates gastric cancer metastasis via regulating FAK nuclear export.
ALKBH5-YTHDF2 m6A modification axis inhibits rheumatoid arthritis progression by suppressing NLRP3.
Smoking-Induced M2-TAMs, via circEML4 in EVs, Promote the Progression of NSCLC through ALKBH5-Regulated m6A Modification of SOCS2 in NSCLC Cells.
NCBP1 enhanced proliferation of DLBCL cells via METTL3-mediated m6A modification of c-Myc.
RBM33 is a unique m6A RNA-binding protein that regulates ALKBH5 demethylase activity and substrate selectivity.
Integrating machine learning and bioinformatics analysis to m6A regulator-mediated methylation modification models for predicting glioblastoma patients' prognosis and immunotherapy response.
METTL3-mediated m6A modification of lnc KCNQ1OT1 promotes doxorubicin resistance in breast cancer by regulating miR-103a-3p/MDR1 axis.
An N6-methyladenosine regulation- and mRNAsi-related prognostic index reveals the distinct immune microenvironment and immunotherapy responses in lower-grade glioma.
Effect of prenatal perfluoroheptanoic acid exposure on spermatogenesis in offspring mice.
m6A‑mediated LINC02038 inhibits colorectal cancer progression via regulation of the FAM172A/PI3K/AKT pathway via competitive binding with miR‑552‑5p.
m6A-enriched lncRNA LINC00839 promotes tumor progression by enhancing TAF15-mediated transcription of amine oxidase AOC1 in nasopharyngeal carcinoma.
RPS15 interacted with IGF2BP1 to promote esophageal squamous cell carcinoma development via recognizing m6A modification.
The emerging role of N6-methyladenine RNA methylation in metal ion metabolism and metal-induced carcinogenesis.
METTL3-mediated ANXA2 inhibition confers neuroprotection in ischemic stroke: Evidence from in vivo and in vitro studies.
EGR1-Driven METTL3 Activation Curtails VIM-Mediated Neuron Injury in Epilepsy.
Protocol for identification and validation of IGF2BP1 target genes in pluripotent human embryonic carcinoma cells.
Emerging role of RNA acetylation modification ac4C in diseases:current advences and future challenges.
TRIM21 ameliorates hepatic glucose and lipid metabolic disorders in type 2 diabetes mellitus by ubiquitination of PEPCK1 and FASN.

Cancer Lett. 2023 May 31. pii: S0304-3835(23)00197-0. [Epub ahead of print] 216246

TROP2 translation mediated by dual m6A/m7G RNA modifications promotes bladder cancer development.

Cong Chen, Yinghui Chao, Chengcheng Zhang, Wenyu Hu, Yapeng Huang, Yifan Lv, Bixia Liu, Ding Ji, Mingrui Liu, Baotong Yang, Lujing Jiang, Yaomin Liang, Haiqing Zhang, Gang Yuan, Xiaoling Ying, Weidong Ji.

  RNA modifications, including adenine methylation (m6A) of mRNA and guanine methylation (m7G) of tRNA, are crucial for the biological function of RNA. However, the mechanism underlying the translation of specific genes synergistically mediated by dual m6A/m7G RNA modifications in bladder cancer (BCa) remains unclear. We demonstrated that m6A methyltransferase METTL3-mediated programmable m6A modification of oncogene trophoblast cell surface protein 2 (TROP2) mRNA promoted its translation during malignant transformation of bladder epithelial cells. m7G methyltransferase METTL1 enhanced TROP2 translation by mediating m7G modification of certain tRNAs. TROP2 protein inhibition decreased the proliferation and invasion of BCa cells in vitro and in vivo. Moreover, synergistical knockout of METTL3/METTL1 inhibited BCa cell proliferation, migration, and invasion; however, TROP2 overexpression partially abrogated its effect. Furthermore, TROP2 expression was significantly positively correlated with the expression levels of METTL3 and METTL1 in BCa patients. Overall, our results revealed that METTL3/METTL1-mediated dual m6A/m7G RNA modifications enhanced TROP2 translation and promoted BCa development, indicating a novel RNA epigenetic mechanism in BCa.

Keywords:  Bladder cancer; RNA modification; TROP2; m(6)A; m(7)G

DOI:  https://doi.org/10.1016/j.canlet.2023.216246
Exp Mol Med. 2023 Jun 01.

The YTHDC1/GLUT3/RNF183 axis forms a positive feedback loop that modulates glucose metabolism and bladder cancer progression.

Bin Yan, Xurui Li, Mou Peng, Yali Zuo, Yinhuai Wang, Pian Liu, Weigang Ren, Xin Jin.

Aberrant glucose metabolism is a characteristic of bladder cancer. Hyperglycemia contributes to the development and progression of bladder cancer. However, the underlying mechanism by which hyperglycemia promotes the aggressiveness of cancers, especially bladder cancer, is still incompletely understood. N6-methyladenosine (m6A) modification is a kind of methylation modification occurring at the N6 position of adenosine that is important for the pathogenesis of urological tumors. Recently, it was found that the m6A reader YTHDC1 is regulated by high-glucose conditions. In our study, we revealed that YTHDC1 is not only regulated by high-glucose conditions but is also downregulated in bladder cancer tissue and associated with the prognosis of cancer. We also showed that YTHDC1 suppresses the malignant progression of and the glycolytic process in bladder cancer cells in an m6A-dependent manner and determined that this effect is partially mediated by GLUT3. Moreover, GLUT3 was found to destabilize YTHDC1 by upregulating RNF183 expression. In summary, we identified a novel YTHDC1/GLUT3/RNF183 feedback loop that regulates disease progression and glucose metabolism in bladder cancer. Collectively, this study provides new insight regarding the pathogenesis of bladder cancer under hyperglycemic conditions and might reveal ideal candidates for the development of drugs for bladder cancer.

DOI: https://doi.org/10.1038/s12276-023-00997-z
Heliyon. 2023 Jun;9(6): e16280

FLOT1, stabilized by WTAP/IGF2BP2 mediated N6-methyladenosine modification, predicts poor prognosis and promotes growth and invasion in gliomas.

Tao Song, Zhongxu Hu, Chong Zeng, Haijun Luo, Jie Liu.

  The expression, function, and mechanism of FLOT1 (flotillin-1) remains unknown in gliomas. Here, the expression and clinical value of FLOT1 in gliomas was bioinformatically and experimentally analyzed via online omics data and local tissues. Moreover, the effects of FLOT1 depletion on cell proliferation and invasion were also detected. Besides, the underlying roles of N6-methyladenosine modification (m6A) in FLOT1 upregulation was further explored. The results demonstrated that FLOT1 was significantly upregulated in gliomas and positively correlated with advanced progression and poor prognosis of patients. FLOT1 silencing notably suppressed the cell proliferation and invasion in gliomas. The expression of WTAP and IGF2BP2was positively correlated with FLOT1 expression and served as the writer and reader of FLOT1 m6A, respectively, which stabilized FLOT1 mRNA and maintained its upregulation in gliomas. Lastly, ectopic expression of FLOT1 could notably restore the inhibitory effects caused by WTAP and IGF2BP2 depletion in glioma cells. Collectively, our results originally confirmed the upregulation and oncogenic roles of FLOT1, and revealed that WTAP/IGF2BP2 mediated m6A contributed to the upregulation of FLOT1 in gliomas, highlighting the promising application of WTAP/IGF2BP2/FLOT1 axis in target treatment of gliomas.

Keywords:  FLOT1; Gliomas; IGF2BP2; WTAP; m6A

DOI:  https://doi.org/10.1016/j.heliyon.2023.e16280
Pharmaceuticals (Basel). 2023 Jan 25. pii: 185. [Epub ahead of print]16(2):

The m6A Reader YTHDF1 Promotes Lung Carcinoma Progression via Regulating Ferritin Mediate Ferroptosis in an m6A-Dependent Manner.

Hongtao Diao, Huiling Tan, Yaju Hu, Ruonan Wang, Pingdong Cai, Bingying Huang, Xiaoqi Shao, Meiling Yan, Chuntong Yin, Yue Zhang.

  N6-methyladenosine (m6A) plays a significant role as an epigenetic mechanism, which is involved in various cancers' progress via regulating mRNA modification. As a crucial m6A "reader", YTHDF1 is able to alter m6A-modified mRNA and promote the protein translation process in multiple cancers. However, the role of YTHDF1 in lung cancer has not been fully investigated. This study focuses on elucidating the function of YTHDF1 in the development of lung cancer and its underlying mechanism. We demonstrated that YTHDF1 was highly expressed in lung carcinoma progression; then, the loss of function experiments in lung cell lines confirmed that knockdown of YTHDF1 suppressed cell proliferation, migration and invasion and induced ferroptosis of lung cancer cells. Further functional assays showed that ferritin (FTH) was identified as the key target of YTHDF1 in lung cancer cells. Furthermore, the overexpression of ferritin in YTHDF1-depleted cells partially restored lung cancer cell suppression. Collectively, our data suggested that the upregulation of YTHDF1 promotes lung cancer carcinogenesis by accelerating ferritin translation in an m6A-dependent manner. We hope that our findings may provide a new target for lung cancer diagnosis and treatment.

Keywords:  N6-methyladenosine (m6A) modification; YTHDF1; ferritin; ferroptosis; lung cancer

DOI:  https://doi.org/10.3390/ph16020185
Inflammation. 2023 May 31.

m6A Regulator-mediated RNA Methylation Modulates Immune Microenvironment of Hepatitis B Virus-related Acute Liver Failure.

Dingchun Li, Ye Liu, Ju Zhou, Yihui Chen, Chunxia Yang, Huaie Liu, Wu Li, Jing You.

  Acute liver failure (ALF) is a rare and complicated disease with a high mortality rate. Emergency liver transplantation is the only treatment method that can improve the ALF prognosis. However, its clinical application remains limited owing to the aggressive nature of liver transplantation, limited donors, and high postoperative mortality. The study investigated the effect of m6A on the immune microenvironment of hepatitis B virus-related ALF (HBV-ALF). In this study, the gene expression data of 47 normal people and 42 HBV-ALF patients were downloaded from the Gene Expression Omnibu (GEO) database. The known 23 m6A regulators which mediated RNA modification patterns were compared and analyzed in these two groups, and the gene diagnosis model of HBV-ALF patients was established based on the analysis results. In addition, we used unsupervised clustering to identify different m6A RNA methylation modification patterns in HBV-ALF based on m6A regulators, and evaluated the immune infiltration and biological differences in these subtypes. In addition, the relationship between m6A genes and immune cell activation in HBV-ACLF patients was explored by immune infiltration analysis. Nineteen m6A regulators mediated RNA methylation (m6A regulators for short) were differentially expressed in HBV-ALF and control groups. m6A regulators could well distinguish control samples from HBV-ALF samples, and m6A regulators might be used as a basis for diagnosing HBV-ALF patients. Immune cells such as activated CD8 T cells, activated B cells, and activated CD4 T cells might play important roles in HBV-ALF, and m6A regulators were closely associated with immune cell infiltration. ALKBH15, CBLL1, IGF2BP2, IGF2BP3, and ZC3H13 were significantly associated with immune cells. Considering 23 m6A regulators, HBV-ALF patients could be classified into two subtypes (cluster 1 and cluster 2) based on different immune cell infiltration. m6A regulators of the IGFBP and YHDF families have extremely different levels in these two subtypes. Differential immune cell infiltration among these subtypes was observed, a total of 913 differentially expressed genes among different m6A modification patterns was identified, and their biological functions were explored. m6A modification might play a crucial role in the diverse and complex immune microenvironment of HBV-ALF patients.

Keywords:  HBV-ALF0; RNA modification; epigenetics; immune microenvironment.; m6A

DOI:  https://doi.org/10.1007/s10753-023-01841-2
Cell Signal. 2023 May 29. pii: S0898-6568(23)00141-9. [Epub ahead of print] 110727

IGF2BP3/HIF1A/YAP signaling plays a role in driving acute-on-chronic liver failure through activating hepatocyte reprogramming.

Cheng Ke, Liu Shu, Li Cai, Zhao Yujun, Wang Qiang.

   BACKGROUND: Acute-on-chronic liver failure (ACLF) is a syndrome with both high prevalence and mortality. However, the underlying mechanisms remain elusive and there is no effective therapeutic approach available. Here we aim to uncover novel molecular mechanisms of ACLF and identify potential therapeutic targets.
METHOD: We performed integrative analysis of 3 transcriptomic datasets and subsequent bioinformatic analysis aiming for potential genes of significance in ACLF development, identifying a critical role of IGF2BP3/HIF1A signaling in development of ACLF. Expression of molecules in IGF2BP3/HIF1A pathway and hepatocyte reprogramming markers in clinical samples were then determined by western blot and quantitative PCR. N6-methyladenosine (m6A) RNA modification of HIF1A was analyzed by m6A dot assay and PCR following m6A-antibody precipitation. The molecular mechanisms among IGFBP3, HIF1α and YAP1 were further validated by gene overexpression and knockdown experiments in HepG2 and Hep3B cells. Cell phenotypes of hepatocyte reprogramming were determined by EdU staining, sphere formation assay and immunoblotting of relevant markers.
RESULTS: Our data demonstrated that IGF2BP3 recognized m6A modification in HIF1A mRNA as an m6A reader, thereby promoting expression of HIF1A by increasing RNA stability. HIF1A activated Rho GTPases (RhoA) and suppressed phosphorylation of YAP via inhibiting LATS1/2, promoting translocation of non-phosphorylated YAP into the nucleus, resulting in fetal liver programme and ultimate hepatic injury in ACLF patients.
CONCLUSION: We reveal a novel molecular mechanism that IGF2BP3/HIF1A/YAP signaling promotes hepatocyte reprogramming, causing hepatic injury in ACLF. Our study provides potential targets for treatment of ACLF.

Keywords:  Acute-on-chronic liver failure (ACLF); Hepatocyte reprogramming/fetal liver programme; Hypoxia-inducible factor (HIF); Insulin-like growth factor-2 RNA-binding protein-3 (IGF2BP3); N6-methyladenosine (m6A) RNA modification; Yes-associated protein (YAP)

DOI:  https://doi.org/10.1016/j.cellsig.2023.110727
Biochim Biophys Acta Mol Cell Res. 2023 May 26. pii: S0167-4889(23)00075-7. [Epub ahead of print] 119503

METTL3 achieves lipopolysaccharide-induced myocardial injury via m6A-dependent stabilization of Myh3 mRNA.

Chengwu Gong, Jinlong Wu, Hao Li, Congcong Luo, Guangyu Ji, Xin Guan, Jichun Liu, Mingsong Wang.

  Septic cardiomyopathy (SCM) was an important pathological component of severe sepsis and septic shock. N6-methyladenosine (m6A) modification was a common RNA modification in both mRNA and non-coding RNAs and was proved to be involved in sepsis and immune disorders. Therefore, the purpose of this study was to investigate the role and mechanism of METTL3 in lipopolysaccharide-induced myocardial injury. We firstly analyzed the expression changes of various m6A-related regulators in human samples in the GSE79962 data and the Receiver Operating Characteristic curve of significantly changed m6A enzymes, showing that METTL3 had a high diagnostic ability in patients with SCM. Western blotting confirmed the high expression of METTL3 in LPS-treated H9C2 cells, which was consistent with the above results in human samples. In vitro and in vivo, the deficiency of METTL3 could improve the cardiac function, cardiac tissue damage, myocardial cell apoptosis and reactive oxygen species levels in LPS-treated H9C2 cells and LPS-induced sepsis rats, respectively. In addition, we obtained 213 differential genes through transcriptome RNA-seq analysis, and conducted GO enrichment analysis and KEGG pathway analysis through DAVID. We also found that the half-life of Myh3 mRNA was significantly reduced after METTL3 deletion and that Myh3 carried several potential m6A modification sites. In conclusion, we found that downregulation of METTL3 reversed LPS-induced myocardial cell and tissue damage and reduced cardiac function, mainly by increasing Myh3 stability. Our study revealed a key role of METTL3-mediated m6A methylation in septic cardiomyopathy, which may offer a potential mechanism for the therapy of septic cardiomyopathy.

Keywords:  LPS; METTL3; Septic cardiomyopathy; m(6)A

DOI:  https://doi.org/10.1016/j.bbamcr.2023.119503
Cell Rep. 2023 Jun 01. pii: S2211-1247(23)00595-8. [Epub ahead of print]42(6): 112584

Mettl3-m6A-Creb1 forms an intrinsic regulatory axis in maintaining iNKT cell pool and functional differentiation.

Menghao You, Jingjing Liu, Jie Li, Ce Ji, Haochen Ni, Wenhui Guo, Jiarui Zhang, Weiwei Jia, Zhao Wang, Yajiao Zhang, Yingpeng Yao, Guotao Yu, Huanyu Ji, Xiaohu Wang, Dali Han, Xuguang Du, Meng Michelle Xu, Shuyang Yu.

  N6-methyladenosine (m6A) methyltransferase Mettl3 is involved in conventional T cell immunity; however, its role in innate immune cells remains largely unknown. Here, we show that Mettl3 intrinsically regulates invariant natural killer T (iNKT) cell development and function in an m6A-dependent manner. Conditional ablation of Mettl3 in CD4+CD8+ double-positive (DP) thymocytes impairs iNKT cell proliferation, differentiation, and cytokine secretion, which synergistically causes defects in B16F10 melanoma resistance. Transcriptomic and epi-transcriptomic analyses reveal that Mettl3 deficiency disturbs the expression of iNKT cell-related genes with altered m6A modification. Strikingly, Mettl3 modulates the stability of the Creb1 transcript, which in turn controls the protein and phosphorylation levels of Creb1. Furthermore, conditional targeting of Creb1 in DP thymocytes results in similar phenotypes of iNKT cells lacking Mettl3. Importantly, ectopic expression of Creb1 largely rectifies such developmental defects in Mettl3-deficient iNKT cells. These findings reveal that the Mettl3-m6A-Creb1 axis plays critical roles in regulating iNKT cells at the post-transcriptional layer.

Keywords:  CP: Immunology; Creb1; Mettl3; development; differentiation; iNKT; invariant natural killer T cell; m(6)A

DOI:  https://doi.org/10.1016/j.celrep.2023.112584
Mol Cancer. 2023 Jun 01. 22(1): 91

The role of m6A methylation in therapy resistance in cancer.

Hengzhao Zhuang, Bo Yu, Dan Tao, Xiaoyan Xu, Yijun Xu, Jian Wang, Yang Jiao, Lili Wang.

  Cancer therapy resistance is the main cause of cancer treatment failure. The mechanism of therapy resistance is a hot topic in epigenetics. As one of the most common RNA modifications, N6-methyladenosine (m6A) is involved in various processes of RNA metabolism, such as stability, splicing, transcription, translation, and degradation. A large number of studies have shown that m6A RNA methylation regulates the proliferation and invasion of cancer cells, but the role of m6A in cancer therapy resistance is unclear. In this review, we summarized the research progress related to the role of m6A in regulating therapy resistance in cancers.

Keywords:  Cancer; Chemoresistance; Radiotherapy resistance; m6A methylation

DOI:  https://doi.org/10.1186/s12943-023-01782-2
Oral Dis. 2023 May 30.

METTL3-mediated ALDH m6 A methylation regulates the malignant behavior of BMI1+ HNSCC stem cells.

Zhi Chen, Jie Chen, Xiaohong Xu, Qiuli Li, Caihua Zhang, Shuai Li, Lianlian Liu, Congyuan Cao, Demeng Chen, Qianting He.

   OBJECTIVES: To reveal the effect and mechanism of methyltransferase-like 3 (METTL3) on cancer stem cells (CSCs) of head and neck squamous cell carcinoma (HNSCC).
MATERIALS AND METHODS: First, we analyzed 14-HNSCC-patients' scRNA-seq dataset and TCGA dataset of HNSCC. Then, Mettl3 knockout or overexpression mice models were studied via tracing and staining technologies. In addition, we took flow cytometry sorting and sphere formation assays to observe tumorigenicity and used cell transfection and western blotting to verify target protein expression levels. Furthermore, methylated RNA immunoprecipitation sequencing (MeRIP-seq) and MeRIP-quantitative real-time PCR (MeRIP-qPCR) were taken to identify the mechanism of Mettl3 regulating Bmi1+ CSCs in HNSCC.
RESULTS: Due to SOX4 transcriptional regulation, METTL3 regulated the malignant behavior of BMI1+ HNSCC stem cells through cell division pathway. The progression and malignancy of HNSCC were decreased after Mettl3 knocked-out, while increased after Mettl3 knocked-in in Bmi1+ CSCs in vivo. Knockdown of Mettl3 inhibited stemness properties of CSCs in vitro. Mechanically, Mettl3 mediated the m6 A modification of ALDH1A3 and ALDH7A1 mRNA in Bmi1+ HNSCC CSCs.
CONCLUSION: Regulated by SOX4, METTL3-mediated ALDH m6 A methylation regulates the malignant behavior of BMI1+ HNSCC CSCs through cell division pathway.

Keywords:  ALDH; BMI1; CSCs; HNSCC; METTL3; SOX4

DOI:  https://doi.org/10.1111/odi.14609
Cancer Commun (Lond). 2023 May 31.

N6-methyladenosine modification of CENPF mRNA facilitates gastric cancer metastasis via regulating FAK nuclear export.

Penghui Xu, Jing Yang, Zetian Chen, Xing Zhang, Yiwen Xia, Sen Wang, Weizhi Wang, Zekuan Xu.

   BACKGROUND: N6-methyladenosine (m6 A) modification is the most common modification that occurs in eukaryotes. Although substantial effort has been made in the prevention and treatment of gastric cancer (GC) in recent years, the prognosis of GC patients remains unsatisfactory. The regulatory mechanism between m6 A modification and GC development needs to be elucidated. In this study, we examined m6 A modification and the downstream mechanism in GC.
METHODS: Dot blotting assays, The Cancer Genome Atlas analysis, and quantitative real-time PCR (qRT-PCR) were used to measure the m6 A levels in GC tissues. Methylated RNA-immunoprecipitation sequencing and RNA sequencing were performed to identify the targets of m6 A modification. Western blotting, Transwell, wound healing, and angiogenesis assays were conducted to examine the role of centromere protein F (CENPF) in GC in vitro. Xenograft, immunohistochemistry, and in vivo metastasis experiments were conducted to examine the role of CENPF in GC in vivo. Methylated RNA-immunoprecipitation-qPCR, RNA immunoprecipitation-qPCR and RNA pulldown assays were used to verify the m6 A modification sites of CENPF. Gain/loss-of-function and rescue experiments were conducted to determine the relationship between CENPF and the mitogen-activated protein kinase (MAPK) signaling pathway in GC cells. Coimmunoprecipitation, mass spectrometry, qRT-PCR, and immunofluorescence assays were performed to explore the proteins that interact with CENPF and elucidate the regulatory mechanisms between them.
RESULTS: CENPF was upregulated in GC and facilitated the metastasis of GC both in vitro and in vivo. Mechanistically, increased m6 A modification of CENPF was mediated by methyltransferase 3, and this modified molecule could be recognized by heterogeneous nuclear ribonucleoprotein A2/B1 (HNRNPA2B1), thereby promoting its mRNA stability. In addition, the metastatic phenotype of CENPF was dependent on the MAPK signaling pathway. Furthermore, CENPF could bind to FAK and promote its localization in the cytoplasm. Moreover, we discovered that high expression of CENPF was related to lymphatic invasion and overall survival in GC patients.
CONCLUSIONS: Our findings revealed that increased m6 A modification of CENPF facilitates the metastasis and angiogenesis of GC through the CENPF/FAK/MAPK and epithelial-mesenchymal transition axis. CENPF expression was correlated with the clinical features of GC patients; therefore, CENPF may serve as a prognostic marker of GC.

Keywords:  CENPF; FAK; MAPK; N6-methyladenosine; epithelial-mesenchymal transition; gastric cancer; metastasis

DOI:  https://doi.org/10.1002/cac2.12443
Biochem Biophys Res Commun. 2023 May 23. pii: S0006-291X(23)00667-8. [Epub ahead of print]668 70-76

ALKBH5-YTHDF2 m6A modification axis inhibits rheumatoid arthritis progression by suppressing NLRP3.

Jianwei Xiao, Xu Cai, Rongsheng Wang, Weijian Zhou, Zhizhong Ye.

  Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease. Recently, NLRP3 has been demonstrated to be closely related to RA. The objective of our research was to analyze the specific mechanism of NLRP3 in RA. The m6A levels of NLRP3 was detected with methylated RNA immunoprecipitation (MeRIP) kit. The mRNA and protein levels of related genes were tested with RT-qPCR and Western blot. The inflammatory factors levels were detected with ELISA kits. The cell proliferative ability was measured with CCK-8 and EdU staining assays. NLRP3 levels was prominently in synovial tissues and fibroblast-like synoviocytes (FLS) from RA patients. NLRP3 silencing suppressed FLS proliferation and inflammatory factor levels. Additionally, ALKBH5 was found to bind with NLRP3, and ALKBH5 silencing suppressed FLS proliferation and inflammatory factor levels while NLRP3 overexpressing neutralized the role of ALKBH5 in FLS. Furthermore, m6A modified induced by ALKBH5 suppressed NLRP3 mRNA level through YTHDC2 in RA, and NLRP3 is a hinge factor in RA progression.

Keywords:  ALKBH5; NLRP3; Rheumatoid arthritis; YTHDC2; m6A

DOI:  https://doi.org/10.1016/j.bbrc.2023.05.087
Adv Sci (Weinh). 2023 May 28. e2300953

Smoking-Induced M2-TAMs, via circEML4 in EVs, Promote the Progression of NSCLC through ALKBH5-Regulated m6A Modification of SOCS2 in NSCLC Cells.

Cheng Cheng, Peiwen Wang, Yi Yang, Xuan Du, Haibo Xia, Jinyuan Liu, Lu Lu, Hao Wu, Qizhan Liu.

  Lung cancer is a commonly diagnosed disease worldwide, with non-small cell lung cancers (NSCLCs) accounting for ≈ 85% of cases. Cigarette smoke is an environmental exposure promoting progression of NSCLC, but its role is poorly understood. This study reports that smoking-induced accumulation of M2-type tumor-associated macrophages (M2-TAMs) surrounding NSCLC tissues promotes malignancy. Specifically, extracellular vesicles (EVs) from cigarette smoke extract (CSE)-induced M2 macrophages promoted malignancy of NSCLC cells in vitro and in vivo. circEML4 in EVs from CSE-induced M2 macrophages is transported to NSCLC cells, where it reduced the distribution of ALKBH5 in the nucleus by interacting with Human AlkB homolog H5 (ALKBH5), resulting in elevated N6-methyladenosine (m6A) modifications. m6A-seq and RNA-seq revealed suppressor of cytokine signaling 2 (SOCS2)-mediated activation of the Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway by regulating m6A modification of SOCS2 via ALKBH5. Down-regulation of circEML4 in EVs from CSE-induced M2 macrophages reversed EVs-enhanced tumorigenicity and metastasis in NSCLC cells. Furthermore, this study found that smoking patients showed an increase in circEML4-positive M2-TAMs. These results indicate that smoking-induced M2-TAMs via circEML4 in EVs promote the NSCLC progression through ALKBH5-regulated m6A modification of SOCS2. This study also reveals that circEML4 in EVs from TAMs acts as a diagnostic biomarker for NSCLC, especially for patients with smoking history.

Keywords:  N6-methyladenosine; circRNAs; non-small cell lung cancer; smoking; tumor-associated macrophages

DOI:  https://doi.org/10.1002/advs.202300953
Sci Rep. 2023 05 27. 13(1): 8606

NCBP1 enhanced proliferation of DLBCL cells via METTL3-mediated m6A modification of c-Myc.

Sibo Meng, Yuan Xia, Mingying Li, Yuyan Wu, Dongmei Wang, Ying Zhou, Daoxin Ma, Jingjing Ye, Tao Sun, Chunyan Ji.

Diffuse large B-cell lymphoma (DLBCL) is malignant hyperplasia of B lymphocytes and standard care cannot satisfactorily meet clinical needs. Potential diagnostic and prognostic DLBCL biomarkers are needed. NCBP1 could bind to the 5'-end cap of pre-mRNAs to participate in RNA processing, transcript nuclear export and translation. Aberrant NCBP1 expression is involved in the pathogenesis of cancers, but little is known about NCBP1 in DLBCL. We proved that NCBP1 is significantly elevated in DLBCL patients and is associated with their poor prognosis. Then, we found that NCBP1 is important for the proliferation of DLBCL cells. Moreover, we verified that NCBP1 enhances the proliferation of DLBCL cells in a METTL3-dependent manner and found that NCBP1 enhances the m6A catalytic function of METTL3 by maintaining METTL3 mRNA stabilization. Mechanistically, the expression of c-MYC is regulated by NCBP1-enhanced METTL3, and the NCBP1/METTL3/m6A/c-MYC axis is important for DLBCL progression. We identified a new pathway for DLBCL progression and suggest innovative ideas for molecular targeted therapy of DLBCL.

DOI: https://doi.org/10.1038/s41598-023-35777-2
Mol Cell. 2023 May 23. pii: S1097-2765(23)00334-9. [Epub ahead of print]

RBM33 is a unique m6A RNA-binding protein that regulates ALKBH5 demethylase activity and substrate selectivity.

Fang Yu, Allen C Zhu, Shun Liu, Boyang Gao, Yuzhi Wang, Nelli Khudaverdyan, Chunjie Yu, Qiong Wu, Yunhan Jiang, Jikui Song, Lingtao Jin, Chuan He, Zhijian Qian.

  Regulation of RNA substrate selectivity of m6A demethylase ALKBH5 remains elusive. Here, we identify RNA-binding motif protein 33 (RBM33) as a previously unrecognized m6A-binding protein that plays a critical role in ALKBH5-mediated mRNA m6A demethylation of a subset of mRNA transcripts by forming a complex with ALKBH5. RBM33 recruits ALKBH5 to its m6A-marked substrate and activates ALKBH5 demethylase activity through the removal of its SUMOylation. We further demonstrate that RBM33 is critical for the tumorigenesis of head-neck squamous cell carcinoma (HNSCC). RBM33 promotes autophagy by recruiting ALKBH5 to demethylate and stabilize DDIT4 mRNA, which is responsible for the oncogenic function of RBM33 in HNSCC cells. Altogether, our study uncovers the mechanism of selectively demethylate m6A methylation of a subset of transcripts during tumorigenesis that may explain demethylation selectivity in other cellular processes, and we showed its importance in the maintenance of tumorigenesis of HNSCC.

Keywords:  ALKBH5 RNA demethylase; DDIT4; HNSCC; RBM33 RNA-binding protein; head and neck squamous cell sarcinoma; m6A RNA modification; substrate selectivity

DOI:  https://doi.org/10.1016/j.molcel.2023.05.010
Aging (Albany NY). 2023 May 23. 15

Integrating machine learning and bioinformatics analysis to m6A regulator-mediated methylation modification models for predicting glioblastoma patients' prognosis and immunotherapy response.

Chuanyu Li, Wangrui Liu, Chengming Liu, Qisheng Luo, Kunxiang Luo, Cuicui Wei, Xueyu Li, Jiancheng Qin, Chuanhua Zheng, Chuanliu Lan, Shiyin Wei, Rong Tan, Jiaxing Chen, Yuanbiao Chen, Huadong Huang, Gaolian Zhang, Haineng Huang, Xiangyu Wang.

   BACKGROUND: Epigenetic regulations of immune responses are essential for cancer development and growth. As a critical step, comprehensive and rigorous explorations of m6A methylation are important to determine its prognostic significance, tumor microenvironment (TME) infiltration characteristics and underlying relationship with glioblastoma (GBM).
METHODS: To evaluate m6A modification patterns in GBM, we conducted unsupervised clustering to determine the expression levels of GBM-related m6A regulatory factors and performed differential analysis to obtain m6A-related genes. Consistent clustering was used to generate m6A regulators cluster A and B. Machine learning algorithms were implemented for identifying TME features and predicting the response of GBM patients receiving immunotherapy.
RESULTS: It is found that the m6A regulatory factor significantly regulates the mutation of GBM and TME. Based on Europe, America, and China data, we established m6Ascore through the m6A model. The model accurately predicted the results of 1206 GBM patients from the discovery cohort. Additionally, a high m6A score was associated with poor prognoses. Significant TME features were found among the different m6A score groups, which demonstrated positive correlations with biological functions (i.e., EMT2) and immune checkpoints.
CONCLUSIONS: m6A modification was important to characterize the tumorigenesis and TME infiltration in GBM. The m6Ascore provided GBM patients with valuable and accurate prognosis and prediction of clinical response to various treatment modalities, which could be useful to guide patient treatments.

Keywords:  consistent clustering; glioblastoma; m6A; metastasis; prognosis

DOI:  https://doi.org/10.18632/aging.204495
Epigenetics. 2023 12;18(1): 2217033

METTL3-mediated m6A modification of lnc KCNQ1OT1 promotes doxorubicin resistance in breast cancer by regulating miR-103a-3p/MDR1 axis.

Zhiyang Zhou, Yukun Cao, Yuan Yang, Shouman Wang, Feiyu Chen.

  Doxorubicin (DOX) resistance in breast cancer (BC) poses a huge challenge for the therapeutic effect on BC. Lnc KCNQ1OT1 play crucial roles in chemotherapy resistance. However, the role and mechanism of lnc KCNQ1OT1 in DOX resistance BC have not been investigated, which merits further exploration. Based on MCF-7 and MDA-MB-231 cells, MCF-7/DOX and MDA-MB-231/DOX cells were established using gradient concentrations of DOX. IC50 values and cell viability were determined using MTT. Cell proliferation was investigated by colony formation. Flow cytometry was performed to examine cell apoptosis and cell cycle. Gene expression was examined using qRT-PCR and western blot. The interactions among METTL3, lnc KCNQ1OT1, miR-103a-3p, and MDR1 were validated with MeRIP-qPCR, RIP, and dual-luciferase reporter gene assays. The results showed that Lnc KCNQ1OT1 was highly expressed in DOX-resistant BC cells, and lnc KCNQ1OT1 depletion could enhance DOX sensitivity in BC cells and DOX-resistant BC cells. Besides, lnc KCNQ1OT1 was modulated by MELLT3 in the manner of m6A modification. MiR-103a-3p could interact with lnc KCNQ1OT1 and MDR1. Overexpression of MDR1 abolished the impacts of lnc KCNQ1OT1 depletion on DOX resistance in BC. In conclusion, our results unveiled that in BC cells and DOX-resistant BC cells, lnc KCNQ1OT1 could be mediated by METTL3 through m6A modification to elevate and stabilize its expression, further inhibiting miR-103a-3p/MDR1 axis to promote DOX resistance, which might provide novel thought to overcome DOX resistance in BC.

Keywords:  Lnc KCNQ1OT1; M6a; METTL3; breast cancer; doxorubicin resistance

DOI:  https://doi.org/10.1080/15592294.2023.2217033
BMC Bioinformatics. 2023 Jun 01. 24(1): 225

An N6-methyladenosine regulation- and mRNAsi-related prognostic index reveals the distinct immune microenvironment and immunotherapy responses in lower-grade glioma.

Guihua Tang, Jianqiao Peng, Longwei Huo, Wen Yin.

   BACKGROUND: N6-methyladenosine (m6A) modification is involved in tumorigenesis and progression as well as closely correlated with stem cell differentiation and pluripotency. Moreover, tumor progression includes the acquisition of stemness characteristics and accumulating loss of differentiation phenotype. Therefore, we integrated m6A modification and stemness indicator mRNAsi to classify patients and predict prognosis for LGG.
METHODS: We performed consensus clustering, weighted gene co-expression network analysis, and least absolute shrinkage and selection operator Cox regression analysis to identify an m6A regulation- and mRNAsi-related prognostic index (MRMRPI). Based on this prognostic index, we also explored the differences in immune microenvironments between high- and low-risk populations. Next, immunotherapy responses were also predicted. Moreover, single-cell RNA sequencing data was further used to verify the expression of these genes in MRMRPI. At last, the tumor-promoting and tumor-associated macrophage polarization roles of TIMP1 in LGG were validated by in vitro experiments.
RESULTS: Ten genes (DGCR10, CYP2E1, CSMD3, HOXB3, CABP4, AVIL, PTCRA, TIMP1, CLEC18A, and SAMD9) were identified to construct the MRMRPI, which was able to successfully classify patients into high- and low-risk group. Significant differences in prognosis, immune microenvironment, and immunotherapy responses were found between distinct groups. A nomogram integrating the MRMRPI and other prognostic factors were also developed to accurately predict prognosis. Moreover, in vitro experiments illustrated that inhibition of TIMP1 could inhibit the proliferation, migration, and invasion of LGG cells and also inhibit the polarization of tumor-associated macrophages.
CONCLUSION: These findings provide novel insights into understanding the interactions of m6A methylation regulation and tumor stemness on LGG development and contribute to guiding more precise immunotherapy strategies.

Keywords:  Immune microenvironment; Immunotherapy responses; Lower-grade glioma (LGG); N6-methyladenosine (m6A) regulation; Nomogram; Prognostic index; mRNAsi

DOI:  https://doi.org/10.1186/s12859-023-05328-7
Ecotoxicol Environ Saf. 2023 May 30. pii: S0147-6513(23)00576-6. [Epub ahead of print]260 115072

Effect of prenatal perfluoroheptanoic acid exposure on spermatogenesis in offspring mice.

Yijie Zhou, Weilian Sun, Qiuqin Tang, Yiwen Lu, Mei Li, Jing Wang, Xiumei Han, Di Wu, Wei Wu.

   BACKGROUND: Perfluoroheptanoic acid (PFHpA), a persistent organic pollutant widespread in the environment, is suspected as an environmental endocrine disruptor for its disturbance effect on hormone homeostasis and reproductive development. Whereas the effect of intrauterine PFHpA exposure during gestation on spermatogenesis of male offspring mice is still unknown.
OBJECTIVE: This study aimed to explore the effect of prenatal PFHpA exposure on the reproductive development of male offspring mice and the role of N6-methyladenosine (m6A) during the process.
METHODS: Fifty-six C57BL/6 pregnant mice were randomly divided into 4 groups. During the gestation period, the pregnant mice were exposed to 0, 0.0015, 0.015, and 0.15 mg/kg bw/d PFHpA from gestational day 1 (GD1) to GD16 by oral gavage. The male offspring mice were sacrificed by spinal dislocation at 7 weeks old. The body weight, testicular weight, and brain weight were weighed, and the intra-testicular testosterone was detected. The sperm qualities were analyzed with computer-aided sperm analysis (CASA). The testicular tissues were taken to analyze the pathological changes and examine the global m6A RNA methylation levels. Quantitative real-time PCR (qRT-PCR) was adopted to figure out the mRNA expression levels of m6A-related enzymes in testicular tissues of different PFHpA treated groups. Methylated RNA immunoprecipitation sequencing (MeRIP-seq) was applied to further explore the m6A RNA methylation at a whole-genome scale.
RESULTS: Compared with the control group, no significant differences were observed in body weight, testicular weight, testicular coefficient, and the visceral-brain ratio of testicular tissue in the PFHpA treated groups. And no significant change was observed in intra-testicular testosterone among the four groups. CASA results showed a decrease of sperm count, sperm concentration, and total cell count, as well as an increase of sperm progressive cells' head area after prenatal PFHpA exposure (P < 0.05). Hematoxylin and eosin staining of pathological sections showed seminiferous tubules morphological change, disorder arrangement of seminiferous epithelium, and reduction of spermatogenic cells in the PFHpA treated groups. PFHpA significantly decreased global levels of m6A RNA methylation in testicular tissue (P < 0.05). Besides, qRT-PCR results showed significant alteration of the mRNA expression levels of seven m6A-related enzymes (Mettl3, Mettl5, Mettl14, Pcif1, Wtap, Hnrnpa2b1, and Hnrnpc) in the PFHpA treated groups (P < 0.05). MeRIP-seq results showed a correlation between prenatal PFHpA exposure and activation and binding of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP). Cnga3 and Mpzl3 showed differential expression in the enrichment subcategories or pathways.
CONCLUSIONS: Exposure to PFHpA during the gestation period would adversely affect the development of seminiferous tubules and testicular m6A RNA methylation in offspring mice, which subsequently interferes with spermatogenesis and leads to reproductive toxicity.

Keywords:  N(6)-methyladenosine (m(6)A); Perfluoroheptanoic acid; Prenatal exposure; RNA methylation; Reproductive toxicity

DOI:  https://doi.org/10.1016/j.ecoenv.2023.115072
Int J Oncol. 2023 Jul;pii: 81. [Epub ahead of print]63(1):

m6A‑mediated LINC02038 inhibits colorectal cancer progression via regulation of the FAM172A/PI3K/AKT pathway via competitive binding with miR‑552‑5p.

Wenjun Liu, Zilang Zhang, Xitu Luo, Kai Qian, Baojun Huang, Jianmin Liang, Zhihao Ma, Jianzhong Deng, Chengyu Yang.

  Long noncoding RNAs (lncRNAs) are a type of regulatory molecule with potential roles in the development of several different malignancies. However, the underlying mechanisms of lncRNAs in colorectal cancer (CRC) are incompletely understood. The present study investigated the molecular mechanism of LINC02038 in CRC. LINC02038 expression was decreased in CRC tissues compared to the para‑cancerous tissues and LINC02038 overexpression markedly reduced the proliferation, vitality, migration and invasive ability and greatly accelerated apoptosis of colorectal cancer cells. Bioinformatics examination indicated that LINC02038 may have targeted microRNA (miR)‑552‑5p. RNA immunoprecipitation and luciferase reporter assays showed that LINC02038 served as a sponge for miR‑552‑5p, hindering target gene FAM172A of miR‑552‑5p degradation. Moreover, methylated RNA immunoprecipitation (MeRIP)‑qualitative PCR assays revealed that YTHDF2 could identify and regulate the METTL3‑mediated LINC02038 N6‑methyladenosine (m6A) modification and increase its degradation, thereby promoting CRC progression via the PI3K/AKT pathway. Based on the CRC clinical specimens, it was shown that LINC02038 was negatively associated with lymphatic metastasis and distant metastasis. These results revealed that m6A/LINC02038/miR‑552‑5p/FAM172A may be a novel anti‑tumor axis and LINC02038 may serve as a biomarker and treatment option for colorectal cancer.

Keywords:  LINC02038; N6‑methyladenosine; ceRNA; colorectal cancer; progression

DOI:  https://doi.org/10.3892/ijo.2023.5529
J Biol Chem. 2023 May 29. pii: S0021-9258(23)01901-4. [Epub ahead of print] 104873

m6A-enriched lncRNA LINC00839 promotes tumor progression by enhancing TAF15-mediated transcription of amine oxidase AOC1 in nasopharyngeal carcinoma.

Wei-Hong Zheng, Zhi-Qing Long, Zi-Qi Zheng, Lu-Lu Zhang, Ye-Lin Liang, Zhi-Xuan Li, Jia-Wei Lv, Jia Kou, Xiao-Hong Hong, Shi-Wei He, Rui Xu, Guan-Qun Zhou, Na Liu, Jun Ma, Ying Sun, Li Lin, Denghui Wei.

  Dysregulation of long non-coding RNAs (lncRNAs) contributes to tumorigenesis by modulating specific cancer-related pathways, but the roles of m6A-enriched lncRNAs and underlying mechanisms remain elusive in nasopharyngeal carcinoma (NPC). Here, we reanalyzed the previous genome-wide analysis of lncRNA profiles in 18 pairs of NPC and normal tissues, as well as in 10 paired samples from NPC with or without posttreatment metastases. We discerned that an oncogenic m6A-enriched lncRNA, LINC00839, which was substantially upregulated in NPC and correlated with poor clinical prognosis, promoted NPC growth and metastasis both in vitro and in vivo. Mechanistically, by using RNA pulldown assay combined with mass spectrometry, we found that LINC00839 interacted directly with the transcription factor, TATA-box binding protein associated factor (TAF15). Besides, ChIP and dual-luciferase report assays demonstrated that LINC00839 coordinated the recruitment of TAF15 to the promoter region of amine oxidase copper-containing 1 (AOC1), which encodes a secreted glycoprotein playing vital roles in various cancers, thereby activating AOC1 transcription in trans. In this study, potential effects of AOC1 in NPC progression were first proposed. Moreover, ectopic expression of AOC1 partially rescued the inhibitory effect of downregulation of LINC00839 in NPC. Furthermore, we showed that silencing vir-like m6A methyltransferase-associated (VIRMA) and insulin-like growth factor 2 mRNA-binding proteins 1 (IGF2BP1) attenuated the expression level and RNA stability of LINC00839 in an m6A-dependent manner. Taken together, our study unveils a novel oncogenic VIRMA/IGF2BP1-LINC00839-TAF15-AOC1 axis, and highlights the significance and prognostic value of LINC00839 expression in NPC carcinogenesis.

Keywords:  LINC00839; m6A; nasopharyngeal carcinoma; progression

DOI:  https://doi.org/10.1016/j.jbc.2023.104873
Signal Transduct Target Ther. 2023 Jun 02. 8(1): 224

RPS15 interacted with IGF2BP1 to promote esophageal squamous cell carcinoma development via recognizing m6A modification.

Yahui Zhao, Yang Li, Rui Zhu, Riyue Feng, Heyang Cui, Xiao Yu, Furong Huang, Ruixiang Zhang, Xiankai Chen, Lei Li, Yinghui Chen, Yuhao Liu, Jinhua Wang, Guanhua Du, Zhihua Liu.

Increased rates of ribosome biogenesis have been recognized as hallmarks of many cancers and are associated with poor prognosis. Using a CRISPR synergistic activation mediator (SAM) system library targeting 89 ribosomal proteins (RPs) to screen for the most oncogenic functional RPs in human esophageal squamous cell carcinoma (ESCC), we found that high expression of RPS15 correlates with malignant phenotype and poor prognosis of ESCC. Gain and loss of function models revealed that RPS15 promotes ESCC cell metastasis and proliferation, both in vitro and in vivo. Mechanistic investigations demonstrated that RPS15 interacts with the K homology domain of insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1), which recognizes and directly binds the 3'-UTR of MKK6 and MAPK14 mRNA in an m6A-dependent manner, and promotes translation of core p38 MAPK pathway proteins. By combining targeted drug virtual screening and functional assays, we found that folic acid showed a therapeutic effect on ESCC by targeting RPS15, which was augmented by the combination with cisplatin. Inhibition of RPS15 by folic acid, IGF2BP1 ablation, or SB203580 treatment were able to suppress ESCC metastasis and proliferation via the p38 MAPK signaling pathway. Thus, RPS15 promotes ESCC progression via the p38 MAPK pathway and RPS15 inhibitors may serve as potential anti-ESCC drugs.

DOI: https://doi.org/10.1038/s41392-023-01428-1
Environ Pollut. 2023 May 25. pii: S0269-7491(23)00899-0. [Epub ahead of print]331(Pt 1): 121897

The emerging role of N6-methyladenine RNA methylation in metal ion metabolism and metal-induced carcinogenesis.

Yaxu Liang, Huan Wang, Bencheng Wu, Ning Peng, Dongming Yu, Xin Wu, Xiang Zhong.

  N6-methyladenine (m6A) is the most common and abundant internal modification in eukaryotic mRNAs, which can regulate gene expression and perform important biological tasks. Metal ions participate in nucleotide biosynthesis and repair, signal transduction, energy generation, immune defense, and other important metabolic processes. However, long-term environmental and occupational exposure to metals through food, air, soil, water, and industry can result in toxicity, serious health problems, and cancer. Recent evidence indicates dynamic and reversible m6A modification modulates various metal ion metabolism, such as iron absorption, calcium uptake and transport. In turn, environmental heavy metal can alter m6A modification by directly affecting catalytic activity and expression level of methyltransferases and demethylases, or through reactive oxygen species, eventually disrupting normal biological function and leading to diseases. Therefore, m6A RNA methylation may play a bridging role in heavy metal pollution-induced carcinogenesis. This review discusses interaction among heavy metal, m6A, and metal ions metabolism, and their regulatory mechanism, focuses on the role of m6A methylation and heavy metal pollution in cancer. Finally, the role of nutritional therapy that targeting m6A methylation to prevent metal ion metabolism disorder-induced cancer is summarized.

Keywords:  Cancers; Metal ions; N(6)-methyladenine; Nutritional therapy

DOI:  https://doi.org/10.1016/j.envpol.2023.121897
FASEB J. 2023 Jul;37(7): e22974

METTL3-mediated ANXA2 inhibition confers neuroprotection in ischemic stroke: Evidence from in vivo and in vitro studies.

Bin Liu, Zhiqun Xing, Feng Song, Dejun Li, Bao Zhao, Chunyang Xu, Wenjun Xia, Hongsheng Ji.

  Given the important role of m6A, the most common and reversible mRNA modification, in the pathogenesis of ischemic stroke, this study investigates the mechanisms of m6A methyltransferase METTL3 in neuronal damage in ischemic stroke. In silico analysis was used to pinpoint the expression of ANXA2, which was verified in clinical peripheral blood samples. SD rats were used for middle cerebral artery occlusion (MCAO) establishment. The experimental data suggested that T lymphocytes were increased in peripheral blood samples of ischemic stroke patients and MCAO rats. The MCAO rats were treated with anti-ANXA2 alone or combined with RP101075 (T lymphocyte infiltration inhibitor), followed by brain injury assessment. Oxygen-glucose deprivation/reoxygenation (OGD/R) was induced in primary cortical neurons, where shRNAs targeting ANXA2 or METTL3, or overexpression plasmids of METTL3 were introduced to verify the regulatory function for METTL3. Inhibition of T lymphocyte migration to the ischemic brain reduced brain injury in MCAO rats and neuronal damage in OGD/R-exposed neurons. Ablation of ANXA2 in T lymphocytes inhibited the migration of T lymphocytes to the ischemic brain and reduced neuronal damage. Mechanistically, METTL3 reduced ANXA2 expression in T lymphocytes through m6A modification and inhibited p38MAPK/MMP-9 pathway activation, exerting protective effects against neuronal damage in ischemic stroke. Overall, this study reveals the neuroprotective effects of METTL3-mediated ANXA2/p38MAPK/MMP-9 inhibition against ischemic stroke.

Keywords:  ANXA2; METTL3; T lymphocytes; ischemic stroke; m6A methyltransferase; m6A modification; neuronal damage; p38MAPK/MMP-9 pathway

DOI:  https://doi.org/10.1096/fj.202300246R
Neurochem Res. 2023 Jun 02.

EGR1-Driven METTL3 Activation Curtails VIM-Mediated Neuron Injury in Epilepsy.

Zhaofei Dong, Fuli Min, Sai Zhang, Huili Zhang, Tao Zeng.

  Uncovering mechanisms underlying epileptogenesis aids in preventing further epilepsy progression and to lessen seizure severity and frequency. The purpose of this study is to explore the antiepileptogenic and neuroprotective mechanisms of EGR1 in neuron injuries encountered in epilepsy. Bioinformatics analysis was conducted to identify the key genes related to epilepsy. The mice were rendered epileptic using the kainic acid protocol, followed by measurement of seizure severity, high amplitude and frequency, pathological changes of hippocampal tissues and neuron apoptosis. Furthermore, an in vitro epilepsy model was constructed in the neurons isolated from newborn mice, which was then subjected to loss- and gain-of-function investigations, followed by neuron injury and apoptosis assessment. Interactions among EGR1, METTL3, and VIM were analyzed by a series of mechanistic experiments. In the mouse and cell models of epilepsy, VIM was robustly induced. However, its knockdown reduced hippocampal neuron injury and apoptosis. Meanwhile, VIM knockdown decreased inflammatory response and neuron apoptosis in vivo. Mechanistic investigations indicated that EGR1 transcriptionally activated METTL3, which in turn downregulated VIM expression through m6A modification. EGR1 activated METTL3 and reduced VIM expression, thereby impairing hippocampal neuron injury and apoptosis, preventing epilepsy progression. Taken together, this study demonstrates that EGR1 alleviates neuron injuries in epilepsy by inducing METTL3-mediated inhibition of VIM, which provides clues for the development of novel antiepileptic treatments.

Keywords:  EGR1; Epilepsy; Hippocampal neuron; METTL3; VIM; m6A modification

DOI:  https://doi.org/10.1007/s11064-023-03950-8
STAR Protoc. 2023 May 25. pii: S2666-1667(23)00305-2. [Epub ahead of print]4(2): 102338

Protocol for identification and validation of IGF2BP1 target genes in pluripotent human embryonic carcinoma cells.

Khine Myint, Linda Shyue Huey Chuang, Junichi Matsuo, Yoshiaki Ito.

  We present a detailed protocol to identify and validate IGF2BP1 target genes in pluripotent human embryonic carcinoma cells (NTERA-2). We first identify the target genes through RNA-immunoprecipitation (RIP) sequencing. We then validate the identified targets through the use of RIP-qPCR assays, determine the m6A status of target genes by m6A-IP, and perform functional validation by quantifying changes in mRNA or protein expression levels upon knockdown of IGF2BP1 or methyltransferases in NTERA-2. For complete details on the use and execution of this protocol, please refer to Myint et al. (2022).1.

Keywords:  Cancer; Cell Biology; Cell-based Assays; Molecular Biology

DOI:  https://doi.org/10.1016/j.xpro.2023.102338
Biochem Pharmacol. 2023 May 27. pii: S0006-2952(23)00219-8. [Epub ahead of print] 115628

Emerging role of RNA acetylation modification ac4C in diseases:current advences and future challenges.

Jie Luo, Jingsong Cao, Cong Chen, Haitao Xie.

  The oldest known highly conserved modification of RNA, N4-acetylcytidine, is widely distributed from archaea to eukaryotes and acts as a posttranscriptional chemical modification of RNA, contributing to the correct reading of specific nucleotide sequences during translation, stabilising mRNA and improving transcription efficiency. Yeast Kre33 and human NAT10, the only known authors of ac4C, modify tRNA with the help of the Tan1/THUMPD1 adapter to stabilise its structure. Currently, the mRNA for N4-acetylcytidine (ac4C), catalysed by NAT10 (N-acetyltransferase 10), has been implicated in a variety of human diseases, particularly cancer. This article reviews advances in the study of ac4C modification of RNA and the ac4C-related gene NAT10 in normal physiological cell development, cancer, premature disease and viral infection and discusses its therapeutic promise and future research challenges.

Keywords:  Cancer; EMT; HGPS; N4-acetylcytidine; NAT10; ac4C

DOI:  https://doi.org/10.1016/j.bcp.2023.115628
Cell Mol Life Sci. 2023 May 30. 80(6): 168

TRIM21 ameliorates hepatic glucose and lipid metabolic disorders in type 2 diabetes mellitus by ubiquitination of PEPCK1 and FASN.

Kaini Zhang, Chen Yang, Xin Zhou, Jin Liang, Jianjin Guo, Min Li, Yi Zhang, Shulin Shao, Peng Sun, Kai Li, Jingjing Huang, Fang Chen, Xiubin Liang, Dongming Su.

  Hepatic glucose and lipid metabolism disorders promote the development and progression of type 2 diabetes mellitus (T2DM), yet the underlying mechanisms are not fully understood. Here, we identify tripartite motif-containing protein 21 (TRIM21), a class IV TRIM family member, as a pivotal regulator of hepatic metabolism in T2DM for the first time. Bioinformatic analysis suggests that TRIM21 expression is significantly reduced in T2DM patients. Intriguingly, in a mouse model of obese diabetes, TRIM21 expression is predominantly reduced in the liver rather than in other metabolic organs. It is further demonstrated that hepatic overexpression of TRIM21 significantly ameliorates glucose intolerance, insulin resistance, hepatic steatosis, and dyslipidemia in obese diabetic mice. In contrast, the knockdown of TRIM21 promotes glucose intolerance, insulin resistance, and triglyceride accumulation. Mechanistically, both phosphoenolpyruvate carboxykinase 1 (PEPCK1) and fatty acid synthase (FASN) are the hepatic targets of TRIM21. We revealed that TRIM21 promotes the degradation of PEPCK1 and FASN through a direct protein-protein interaction mediated K48-linked ubiquitination. Notably, overexpression of PEPCK1 and FASN essentially abolished the beneficial effects achieved by TRIM21 overexpression in obese diabetic mice. Overall, our data demonstrate that TRIM21 is a novel regulator of hepatic metabolic disorder, and suggest TRIM21 as a promising therapeutic target for T2DM.

Keywords:  FASN stability; Hepatic steatosis; Insulin resistance; PEPCK1 stability; TRIM21; Ubiquitination

DOI:  https://doi.org/10.1007/s00018-023-04820-w