METTL3-mediated m6A modification of ZBTB4 mRNA is involved in the smoking-induced EMT in cancer of the lung

Dynamic RNA methylation modifications and their regulatory role in mammalian development and diseases

Among over 170 different types of chemical modifications on RNA nucleobases identified so far, RNA methylation is the major type of epitranscriptomic modifications existing on almost all types of RNAs, and has been demonstrated to participate in the entire process of RNA metabolism, including transcription, pre-mRNA alternative splicing and maturation, mRNA nucleus export, mRNA degradation and stabilization, mRNA translation. Attributing to the development of high-throughput detection technologies and the identification of both dynamic regulators and recognition proteins, mechanisms of RNA methylation modification in regulating the normal development of the organism as well as various disease occurrence and developmental abnormalities upon RNA methylation dysregulation have become increasingly clear. Here, we particularly focus on three types of RNA methylations: N6-methylcytosine (m6A), 5-methylcytosine (m5C), and N7-methyladenosine (m7G). We summarize the elements related to their dynamic installment and removal, specific binding proteins, and the development of high-throughput detection technologies. Then, for a comprehensive understanding of their biological significance, we also overview the latest knowledge on the underlying mechanisms and key roles of these three mRNA methylation modifications in gametogenesis, embryonic development, immune system development, as well as disease and tumor progression.

Exosomes: efficient macrophage-related immunomodulators in chronic lung diseases

Macrophages, the predominant immune cells in the lungs, play a pivotal role in maintaining the delicate balance of the pulmonary immune microenvironment. However, in chronic inflammatory lung diseases and lung cancer, macrophage phenotypes undergo distinct transitions, with M1-predominant macrophages promoting inflammatory damage and M2-predominant macrophages fostering cancer progression. Exosomes, as critical mediators of intercellular signaling and substance exchange, participate in pathological reshaping of macrophages during development of pulmonary inflammatory diseases and lung cancer. Specifically, in inflammatory lung diseases, exosomes promote the pro-inflammatory phenotype of macrophages, suppress the anti-inflammatory phenotype, and subsequently, exosomes released by reshaped macrophages further exacerbate inflammatory damage. In cancer, exosomes promote pro-tumor tumor-associated macrophages (TAMs); inhibit anti-tumor TAMs; and exosomes released by TAMs further enhance tumor proliferation, metastasis, and resistance to chemotherapy. Simultaneously, exosomes exhibit a dual role, holding the potential to transmit immune-modulating molecules and load therapeutic agents and offering prospects for restoring immune dysregulation in macrophages during chronic inflammatory lung diseases and lung cancer. In chronic inflammatory lung diseases, this is manifested by exosomes reshaping anti-inflammatory macrophages, inhibiting pro-inflammatory macrophages, and alleviating inflammatory damage post-reshaping. In lung cancer, exosomes reshape anti-tumor macrophages, inhibit pro-tumor macrophages, and reshaped macrophages secrete exosomes that suppress lung cancer development. Looking ahead, efficient and targeted exosome-based therapies may emerge as a promising direction for treatment of pulmonary diseases.

Cigarette Smoke Extract-Treated Mouse Airway Epithelial Cells-Derived Exosomal LncRNA MEG3 Promotes M1 Macrophage Polarization and Pyroptosis in Chronic Obstructive Pulmonary Disease by Upregulating TREM-1 via m6A Methylation

Cigarette smoke extract (CSE)-treated mouse airway epithelial cells (MAECs)-derived exosomes accelerate the progression of chronic obstructive pulmonary disease (COPD) by upregulating triggering receptor expressed on myeloid cells 1 (TREM-1); however, the specific mechanism remains unclear. We aimed to explore the potential mechanisms of CSE-treated MAECs-derived exosomes on M1 macrophage polarization and pyroptosis in COPD. In vitro, exosomes were extracted from CSE-treated MAECs, followed by co-culture with macrophages. In vivo, mice exposed to cigarette smoke (CS) to induce COPD, followed by injection or/and intranasal instillation with oe-TREM-1 lentivirus. Lung function and pathological changes were evaluated. CD68+ cell number and the levels of iNOS, TNF-α, IL-1β (M1 macrophage marker), and pyroptosis-related proteins (NOD-like receptor family pyrin domain containing 3, apoptosis-associated speck-like protein containing a caspase-1 recruitment domain, caspase-1, cleaved-caspase-1, gasdermin D [GSDMD], and GSDMD-N) were examined. The expression of maternally expressed gene 3 (MEG3), spleen focus forming virus proviral integration oncogene (SPI1), methyltransferase 3 (METTL3), and TREM-1 was detected and the binding relationships among them were verified. MEG3 increased N6-methyladenosine methylation of TREM-1 by recruiting SPI1 to activate METTL3. Overexpression of TREM-1 or METTL3 negated the alleviative effects of MEG3 inhibition on M1 polarization and pyroptosis. In mice exposed to CS, EXO-CSE further aggravated lung injury, M1 polarization, and pyroptosis, which were reversed by MEG3 inhibition. TREM-1 overexpression negated the palliative effects of MEG3 inhibition on COPD mouse lung injury. Collectively, CSE-treated MAECs-derived exosomal long non-coding RNA MEG3 may expedite M1 macrophage polarization and pyroptosis in COPD via the SPI1/METTL3/TREM-1 axis.

Epigenetic regulation of mRNA mediates the phenotypic plasticity of cancer cells during metastasis and therapeutic resistance (Review)

Plasticity, the ability of cancer cells to transition between differentiation states without genomic alterations, has been recognized as a major source of intratumoral heterogeneity. It has a crucial role in cancer metastasis and treatment resistance. Thus, targeting plasticity holds tremendous promise. However, the molecular mechanisms of plasticity in cancer cells remain poorly understood. Several studies found that mRNA, which acts as a bridge linking the genetic information of DNA and protein, has an important role in translating genotypes into phenotypes. The present review provided an overview of the regulation of cancer cell plasticity occurring via changes in the transcription and editing of mRNAs. The role of the transcriptional regulation of mRNA in cancer cell plasticity was discussed, including DNA‑binding transcriptional factors, DNA methylation, histone modifications and enhancers. Furthermore, the role of mRNA editing in cancer cell plasticity was debated, including mRNA splicing and mRNA modification. In addition, the role of non‑coding (nc)RNAs in cancer plasticity was expounded, including microRNAs, long intergenic ncRNAs and circular RNAs. Finally, different strategies for targeting cancer cell plasticity to overcome metastasis and therapeutic resistance in cancer were discussed.

The role of N6-methyladenosine methylation in PAHs-induced cancers

Polycyclic aromatic hydrocarbons (PAHs), which are a wide range of environmental toxicants, may act on humans through inhalation, ingestion, and skin contact, resulting in a range of toxic reactions. Epidemiological studies showed that long-term exposure to PAHs in the occupational and living environment results in a substantial rise in the incidence rate of many cancers in the population, so the prevention and treatment of these diseases have become a major worldwide public health problem. N6-methyladenosine (m6A) modification greatly affects the metabolism of RNA and is implicated in the etiopathogenesis of many kinds of diseases. In addition, m6A-binding proteins have an important role in disease development. The abnormal expression of these can cause the malignant proliferation, migration, invasion, and metastasis of cancers. Furthermore, a growing number of studies revealed that environmental toxicants are one of the cancer risk factors and are related to m6A modifications. Exposure to environmental toxicants can alter the methylation level of m6A and the expression of the m6A-binding protein, thus promoting the occurrence and development of cancers through diverse mechanisms. m6A may serve as a biomarker for early environmental exposure. Through the study of m6A, we can find the health injury early, thus providing a new sight for preventing and curing environmental health-related diseases.

DNA methylation regulator-mediated modification patterns and risk of intracranial aneurysm: a multi-omics and epigenome-wide association study integrating machine learning, Mendelian randomization, eQTL and mQTL data

BACKGROUND

Intracranial aneurysms (IAs) pose a significant and intricate challenge. Elucidating the interplay between DNA methylation and IA pathogenesis is paramount to identify potential biomarkers and therapeutic interventions.

METHODS

We employed a comprehensive bioinformatics investigation of DNA methylation in IA, utilizing a transcriptomics-based methodology that encompassed 100 machine learning algorithms, genome-wide association studies (GWAS), Mendelian randomization (MR), and summary-data-based Mendelian randomization (SMR). Our sophisticated analytical strategy allowed for a systematic assessment of differentially methylated genes and their implications on the onset, progression, and rupture of IA.

RESULTS

We identified DNA methylation-related genes (MRGs) and associated molecular pathways, and the MR and SMR analyses provided evidence for potential causal links between the observed DNA methylation events and IA predisposition.

CONCLUSION

These insights not only augment our understanding of the molecular underpinnings of IA but also underscore potential novel biomarkers and therapeutic avenues. Although our study faces inherent limitations and hurdles, it represents a groundbreaking initiative in deciphering the intricate relationship between genetic, epigenetic, and environmental factors implicated in IA pathogenesis.

Emerging Roles for DNA 6mA and RNA m6A Methylation in Mammalian Genome

Epigenetic methylation has been shown to play an important role in transcriptional regulation and disease pathogenesis. Recent advancements in detection techniques have identified DNA N6-methyldeoxyadenosine (6mA) and RNA N6-methyladenosine (m6A) as methylation modifications at the sixth position of adenine in DNA and RNA, respectively. While the distributions and functions of 6mA and m6A have been extensively studied in prokaryotes, their roles in the mammalian brain, where they are enriched, are still not fully understood. In this review, we provide a comprehensive summary of the current research progress on 6mA and m6A, as well as their associated writers, erasers, and readers at both DNA and RNA levels. Specifically, we focus on the potential roles of 6mA and m6A in the fundamental biological pathways of the mammalian genome and highlight the significant regulatory functions of 6mA in neurodegenerative diseases.

Effect of polycyclic aromatic hydrocarbons on cancer risk causally mediated via vitamin D levels

Polycyclic aromatic hydrocarbons (PAHs) widely exist in environmental substrates and are closely related to individual circulating vitamin D levels and tumorigenesis. Therefore, we proposed to evaluate the relationship between PAH exposure, vitamin D, and the risks for 14 cancer types via a causal inference framework underlying the mediation analysis. We evaluated seven urine monohydroxylated PAH (OH-PAH) and serum vitamin D concentrations of 3306 participants from the National Health and Nutrition Examination Survey between the 2013 and 2016 survey cycles and measured PAH concentrations in 150 subjects from the Nanjing cohort. We observed a significant negative dose-response relationship between increased OH-PAH levels and vitamin D deficiency. Each unit increase in ∑OH-PAHs could lead to a decrease in vitamin D levels (βadj  = -0.98, Padj  = 2.05 × 10-4 ). Body mass index could have interaction effects with ∑OH-PAHs and affect vitamin D levels. Coexposure to naphthalene and fluorene metabolites mutually affected vitamin D levels. Notably, vitamin D could causally mediate the relationship between OH-PAHs and nine types of cancer (e.g., colorectal cancer, liver cancers, etc.). This study first emphasizes the causal cascade of individual OH-PAHs, vitamin D, and cancer risk, providing insights into prevention via the environment.

Smoking and tetramer tryptase accelerate intervertebral disc degeneration by inducing METTL14-mediated DIXDC1 m6 modification

Although cigarette smoking (CS) and low back pain (LBP) are common worldwide, their correlations and the mechanisms of action remain unclear. We have shown that excessive activation of mast cells (MCs) and their proteases play key roles in CS-associated diseases, like asthma, chronic obstructive pulmonary disease (COPD), blood coagulation, and lung cancer. Previous studies have also shown that MCs and their proteases induce degenerative musculoskeletal disease. By using a custom-designed smoke-exposure mouse system, we demonstrated that CS results in intervertebral disc (IVD) degeneration and release of MC-restricted tetramer tryptases (TTs) in the IVDs. TTs were found to regulate the expression of methyltransferase 14 (METTL14) at the epigenetic level by inducing N6-methyladenosine (m6A) deposition in the 3' untranslated region (UTR) of the transcript that encodes dishevelled-axin (DIX) domain-containing 1 (DIXDC1). That reaction increases the mRNA stability and expression of Dixdc1. DIXDC1 functionally interacts with disrupted in schizophrenia 1 (DISC1) to accelerate the degeneration and senescence of nucleus pulposus (NP) cells by activating a canonical Wnt pathway. Our study demonstrates the association between CS, MC-derived TTs, and LBP. These findings raise the possibility that METTL14-medicated DIXDC1 m6A modification could serve as a potential therapeutic target to block the development of degeneration of the NP in LBP patients.

The critical roles of m6A RNA methylation in lung cancer: from mechanism to prognosis and therapy

Lung cancer, a highly malignant disease, greatly affects patients' quality of life. N6-methyladenosine (m6A) is one of the most common posttranscriptional modifications of various RNAs, including mRNAs and ncRNAs. Emerging studies have demonstrated that m6A participates in normal physiological processes and that its dysregulation is involved in many diseases, especially pulmonary tumorigenesis and progression. Among these, regulators including m6A writers, readers and erasers mediate m6A modification of lung cancer-related molecular RNAs to regulate their expression. Furthermore, the imbalance of this regulatory effect adversely affects signalling pathways related to lung cancer cell proliferation, invasion, metastasis and other biological behaviours. Based on the close association between m6A and lung cancer, various prognostic risk models have been established and novel drugs have been developed. Overall, this review comprehensively elaborates the mechanism of m6A regulation in the development of lung cancer, suggesting its potential for clinical application in the therapy and prognostic assessment of lung cancer.

Cigarette smoking, by accelerating the cell cycle, promotes the progression of non-small cell lung cancer through an HIF-1α-METTL3-m6A/CDK2AP2 axis

Cigarette smoking killed about 8 million people every year and promoted non-small cell lung cancer (NSCLC). We investigated the molecular mechanism of smoking-promoted NSCLC progression. Relative to non-smokers, NSCLC patients who were smokers had a higher tumor malignancy. For NSCLC cells, cigarette smoke extract (CSE) increased levels of HIF-1α, METTL3, Cyclin E1, and CDK2 and promoted the G1/S transition, which promoted cell proliferation. Down-regulation HIF-1α or METTL3 reversed these effects. meRIP-seq and RNA-seq revealed the m⁶A modification in Cyclin Dependent Kinase 2 Associated Protein 2 (CDK2AP2) mRNA as the key downstream target. Further, for NSCLC cells exposed to CSE, HIF-1α activated METTL3 transcription. Xenografts in nude mice demonstrated that HIF-1α via METTL3 participated in tumor growth. In NSCLC tissues of smokers, protein levels of HIF-1α and METTL3 were higher, and levels of CDK2AP2 were lower. In conclusion, HIF-1α via METTL3 regulation of the m⁶A modification of CDK2AP2 mRNA drives smoking-induced progression of NSCLC through promoting cell proliferation. This is a previously unknown molecular mechanism for smoking-induced NSCLC progression. The results have potential value for treatment of NSCLC, especially for patients who smoke.

RNF2 inhibits E-Cadherin transcription to promote hepatocellular carcinoma metastasis via inducing histone mono-ubiquitination

RNF2 is a RING domain-containing E3 ubiquitin ligase that mediate histone H2A mono-ubiquitination to repress gene transcription, but its expression patterns and molecular function in hepatocellular carcinoma (HCC) remain unclear. Herein, we extracted data from TGCA database and validated RNF2 expression in our own cohort, which revealed that RNF2 was highly expressed in HCC and was associated with malignant characteristics and poor prognosis of HCC. Moreover, RNF2 was demonstrated to promote HCC metastasis via enhancing epithelial-mesenchymal transition (EMT) both in vitro and in vivo. Mechanistically, RNF2 repressed E-Cadherin transcription by increasing the deposition of H2K119ub at the E-Cadherin promoter region. In addition, RNF2-regulated crosstalk between H2AK119ub, H3K27me3 and H3K4me3 synergistically reduced E-Cadherin transcription, which promoted EMT and HCC metastasis. These results indicate that RNF2 played an oncogenic role in HCC progression via inducing EMT, and RNF2 could be a potential therapeutic target for HCC.

Identification of ZBTB4 as an immunological biomarker that can inhibit the proliferation and invasion of pancreatic cancer

BACKGROUND

Zinc finger and BTB domain-containing protein 4 (ZBTB4) belongs to the zinc finger protein family, which has a role in regulating epigenetic inheritance and is associated with cell differentiation and proliferation. Previous studies have identified aberrant ZBTB4 expression in cancer and its ability to modulate disease progression, but studies on the immune microenvironment, immunotherapy and its role in cancer are still lacking.

METHODS

Human pan-cancer and normal tissue transcriptome data were obtained from The Cancer Genome Atlas. The pan-cancer genomic alteration landscape of ZBTB4 was investigated with the online tool. The Kaplan-Meier method was used to evaluate the prognostic significance of ZBTB4 in pancreatic cancer. In parallel, ZBTB4 interacting molecules and potential functions were analyzed by co-expression and the correlation between ZBTB4 and immune cell infiltration, immune modulatory cells and efficacy of immune checkpoint therapy was explored. Next, we retrieved the Gene Expression Omnibus database expression datasets of ZBTB4 and investigated ZBTB4 expression and clinical significance in pancreatic cancer by immunohistochemical staining experiments. Finally, cell experiments were performed to investigate changes in pancreatic cancer cell proliferation, migration and invasion following overexpression and knockdown of ZBTB4.

FINDINGS

ZBTB4 showed loss of expression in the majority of tumors and possessed the ability to predict cancer prognosis. ZBTB4 was closely related to the tumor immune microenvironment, immune cell infiltration and immunotherapy efficacy. ZBTB4 had good diagnostic performance for pancreatic cancer in the clinic, and ZBTB4 protein expression was lost in pancreatic cancer tumor tissues. Cell experiments revealed that overexpression of ZBTB4 inhibited the proliferation, migration and invasion of pancreatic cancer cells, while silencing ZBTB4 showed the opposite effect.

CONCLUSIONS

According to our results, ZBTB4 is present in pancreatic cancer with aberrant expression and is associated with an altered immune microenvironment. We show that ZBTB4 is a promising marker for cancer immunotherapy and cancer prognosis and has the potential to influence pancreatic cancer progression.

N6-methyladenosine reader YTHDF family in biological processes: Structures, roles, and mechanisms

As the most abundant and conserved internal modification in eukaryote RNAs, N6-methyladenosine (m6A) is involved in a wide range of physiological and pathological processes. The YT521-B homology (YTH) domain-containing family proteins (YTHDFs), including YTHDF1, YTHDF2, and YTHDF3, are a class of cytoplasmic m6A-binding proteins defined by the vertebrate YTH domain, and exert extensive functions in regulating RNA destiny. Distinct expression patterns of the YTHDF family in specific cell types or developmental stages result in prominent differences in multiple biological processes, such as embryonic development, stem cell fate, fat metabolism, neuromodulation, cardiovascular effect, infection, immunity, and tumorigenesis. The YTHDF family mediates tumor proliferation, metastasis, metabolism, drug resistance, and immunity, and possesses the potential of predictive and therapeutic biomarkers. Here, we mainly summary the structures, roles, and mechanisms of the YTHDF family in physiological and pathological processes, especially in multiple cancers, as well as their current limitations and future considerations. This will provide novel angles for deciphering m6A regulation in a biological system.

Interaction between N6-methyladenosine (m6A) modification and environmental chemical-induced diseases in various organ systems

A wide variety of chemicals are ubiquitous in the environment and thus exposure to these environmental chemicals poses a serious threat to public health. Particularly, environmental factors such as air pollution, heavy metals, and endocrine-disrupting chemicals (EDCs) can lead to diseases in various organ systems. Recent research in environmental epigenetics has demonstrated that N6-methyladenosine (m6A) modification is a key mechanism of environment-related diseases. m6A modification is the most abundant chemical modification in mRNAs, which can specifically regulate gene expression by affecting RNA translation, stability, processing, and nuclear export. In this review, we discussed how environmental chemicals affected m6A modification and mediated environment-related disease occurrence by classifying the diseases of various systems. Here, we conclude that environmental chemicals alter the levels of m6A and its modulators, which then participate in the occurrence of diseases in various systems by regulating gene expression and downstream signaling pathways such as METTL3/m6A ZBTB4/YTHDF2/EZH2, Foxo3a/FTO/m6A ephrin-B2/YTHDF2, and HIF1A/METTL3/m6A BIRC5/IGF2BP3/VEGFA. Considering the significant role of m6A and its modulators in response to environmental chemicals, they are expected to be used as biomarkers of environment-related diseases. Additionally, targeting m6A modulators using small molecule inhibitors and activators is expected to be a new method for the treatment of environment-related diseases. This review systematically and comprehensively clarifies the important role of m6A in diseases caused by environmental chemicals, thus establishing a scientific basis for the treatment of diseases in various organ systems.

S1PR2 is Important for Cigarette Smoke-induced Pyroptosis in Human Bronchial Epithelial Cells

BACKGROUND

Chronic obstructive pulmonary disease and other respiratory inflammatory diseases are often associated with cigarette smoke exposure. However, the underlying molecular mechanism remains unclear.

AIM OF THE STUDY

This study aimed to investigate the role of sphingosine-1-phosphate receptor 2 (S1PR2) in cigarette smoke extract (CSE)-induced inflammation and pyroptosis in human bronchial epithelial (HBE) cells.

METHODS

CSE was administered to HBE cells and inflammation and pyroptosis were assessed. The mRNA levels of S1PR2, NLRP3, IL-1β, and IL-18 in HBE cells were detected by quantitative RT-PCR. Secreted protein levels of IL-1β and IL-18 in the culture supernatants were detected using enzyme-linked immunosorbent assay. Western blotting was used to measure the levels of S1PR2 and pyroptosis-related proteins (NLRP3, ASC, caspase-1, GSDMD, IL-1β, and IL-18).

RESULTS

Our study revealed an upregulated expression of S1PR2, NLRP3, ASC, caspase-1, GSDMD, IL-1β, and regulated IL-18 in HBE cells after CSE exposure. Genetic blockage of S1PR2 could reverse the increased expression of these proteins related to CSE-induced pyroptosis. Conversely, S1PR2 overexpression increased CSE-induced pyroptosis by upregulating the expression of NLRP3, ASC, caspase-1, GSDMD, IL-1β, and IL-18 in HBE cells.

CONCLUSIONS

Our results revealed that a novel S1PR2 signaling pathway may be involved in the pathogenesis of CSE-induced inflammation and pyroptosis in HBE cells. Thus, S1PR2 inhibitors could be an effective treatment for cigarette smoke-induced airway inflammation and injury.

Role of RNA modifications in carcinogenesis and carcinogen damage response

The field of epitranscriptomics encompasses the study of post-transcriptional RNA modifications and their regulatory enzymes. Among the numerous RNA modifications, N6 -methyladenosine (m6 A) has been identified as the most common internal modification of messenger RNA (mRNA). Although m6 A modifications were first discovered in the 1970s, advances in technology have revived interest in this field, driving an abundance of research into the role of RNA modifications in various biological processes, including cancer. As analogs to epigenetic modifications, RNA modifications also play an important role in carcinogenesis by regulating gene expression post-transcriptionally. A growing body of evidence suggests that carcinogens can modulate RNA modifications to alter the expression of oncogenes or tumor suppressors during cellular transformation. Additionally, the expression and activity of the enzymes that regulate RNA modifications can be dysregulated and contribute to carcinogenesis, making these enzymes promising targets of drug discovery. Here we summarize the roles of RNA modifications during carcinogenesis induced by exposure to various environmental carcinogens, with a main focus on the roles of the most widely studied m6 A mRNA methylation.

miRNA-576-5p promotes endometrial cancer cell growth and metastasis by targeting ZBTB4

PURPOSE

MicroRNAs (miRNAs) have already been shown to have a strong correlation with the invasion and metastasis capacity of tumor cells. The present research examined the function of miRNA-576-5p (miR-576-5p) in the development of endometrial cancer (EC).

METHODS

miR-576-5p and ZBTB4 expression in EC and benign endometrial tissues was measured using quantitative real-time PCR (qRT-PCR) and western blot. To evaluate the proliferation ability of tumor cells in vitro, 2,5-diphenyl-2H-tetrazolium bromide (MTT) and colony formation assays were carried out. The effect of miR-576-5p on the proliferation ability of EC cells in vivo was measured by the tumor formation in nude mice. The migration and invasion ability of tumor cells was determined using the transwell assay. To confirm the association between expressions of miR-576-5p and zinc finger and BTB domain containing four (ZBTB4), western blot, qRT-PCR, and luciferase assay were carried out.

RESULTS

miR-576-5p expression increased significantly in EC samples than in benign endometrial tissues. The level of miR-576-5p was significantly higher in the polymerase ε (POLE) ultramutated subgroup compared to the other three subgroups. High levels of miR-576-5p expression were linked to a shorter progression-free interval time in the copy number high subgroup. Furthermore, upregulated miR-576-5p facilitated EC cell invasion and migration in vitro and promoted the proliferation of EC tumor cell lines both in vitro and in vivo. Moreover, this study showed that the expression of ZBTB4 decreased in patients with EC, and the dual-luciferase reporter assay confirmed that miR-576-5p binds directly to the 3'-UTR of ZBTB4 and inhibits the expression of ZBTB4. An increase in miR-576-5p expression leads to a decrease in the mRNA and protein expression level of ZBTB4. The effects of miR-576-5p can be reversed by overexpression of ZBTB4.

CONCLUSION

miR-576-5p promoted proliferation and metastasis capacity of EC cells by inhibiting ZBTB4 expression. We hypothesized that miR-576-5p could be a prospective therapeutic target for EC.

lncRNA ZNRD1-AS1 promotes malignant lung cell proliferation, migration, and angiogenesis via the miR-942/TNS1 axis and is positively regulated by the m6A reader YTHDC2

RATIONALE

Lung cancer is the most prevalent form of cancer and has a high mortality rate, making it a global public health concern. The N⁶-methyladenosine (m⁶A) modification is a highly dynamic and reversible process that is involved in a variety of essential biological processes. Using in vitro, in vivo, and multi-omics bioinformatics, the present study aims to determine the function and regulatory mechanisms of the long non-coding (lnc)RNA zinc ribbon domain-containing 1-antisense 1 (ZNRD1-AS1).

METHODS

The RNAs that were bound to the m⁶A 'reader' were identified using YTH domain-containing 2 (YTHDC2) RNA immunoprecipitation (RIP)-sequencing. Utilizing methylated RIP PCR/quantitative PCR, pull-down, and RNA stability assays, m⁶A modification and ZNRD1-AS1 regulation were analyzed. Using bioinformatics, the expression levels and clinical significance of ZNRD1-AS1 in lung cancer were evaluated. Using fluorescent in situ hybridization and quantitative PCR assays, the subcellular location of ZNRD1-AS1 was determined. Using cell migration, proliferation, and angiogenesis assays, the biological function of ZNRD1-AS1 in lung cancer was determined. In addition, the tumor suppressor effect of ZNRD1-AS1 in vivo was validated using a xenograft animal model. Through bioinformatics analysis and in vitro assays, the downstream microRNAs (miRs) and competing endogenous RNAs were also predicted and validated.

RESULTS

This study provided evidence that m⁶A modification mediates YTHDC2-mediated downregulation of ZNRD1-AS1 in lung cancer and cigarette smoke-exposed cells. Low levels of ZNRD1-AS1 expression were linked to adverse clinicopathological characteristics, immune infiltration, and prognosis. ZNRD1-AS1 overexpression was shown to suppress lung cancer cell proliferation, migration, and angiogenesis in vitro and in vivo, and to reduce tumor growth in nude mice. ZNRD1-AS1 expression was shown to be controlled by treatment of cells with either the methylation inhibitor 3-Deazaadenosine or the demethylation inhibitor Meclofenamic. Furthermore, the miR-942/tensin 1 (TNS1) axis was demonstrated to be the downstream regulatory signaling pathway of ZNRD1-AS1.

CONCLUSIONS

ZNRD1-AS1 serves an important function and has clinical relevance in lung cancer. In addition, the findings suggested that m⁶A modification could mediate the regulation of the ZNRD1-AS1/miR-942/TNS1 axis via the m⁶A reader YTHDC2.

RNA m6A methyltransferase METTL14 promotes the procession of non-small cell lung cancer by targeted CSF1R

BACKGROUND

Non-small cell lung cancer (NSCLC) is one of the most malignant cancer types, characterized by a poor prognosis. N6-methyladenosine (m6A) is a prevalent internal modification of mRNA. METTL14, an RNA methyltransferase that mediates m6A modification, is implicated in mRNA biogenesis. However, the biomechanism of METTL14 in NSCLC is not very clear.

METHODS

Here, immunohistochemical (IHC) assay was employed to detect METTL14 in NSCLC tissues. The biological functions of METTL14 were demonstrated using cell transfection, cell proliferation assay, cell clone formation assay, cell cycle analysis, cell death analysis, transwell and wound healing assays. Transcriptome and methylated RNA immunoprecipitation (MERIP)-sequencing were used to explore the pathways and potential mechanism of METTL14 in NSCLC. RNA sequencing, METTL14 rip-sequencing, and METTL14 merip-sequencing were conducted to identify the potential targets of METTL14.

RESULTS

METTL14 was significantly correlated with clinical pathological parameters of differentiation and M stage. Additionally, METTL14 promotes cell proliferation, induces cell death, and enhances cell migration and invasion in vitro. Transcriptome and MeRIP-sequencing reveal oncogenic mechanism of METTL14. RIP-sequencing highlights CSF1R and AKR1C1 as targets of METTL14. After validation with TCGA dataset, colony stimulating factor 1 receptor (CSF1R) showed significant positive coefficient with METTL14, and was presumed to be one target of METTl14 in lung cancer and verified by the cellular experiments.

CONCLUSION

In conclusion, our results revealed the clinical significance of m6A RNA modification atlas, the function, and molecular targets CSF1R of METTL14 in NSCLC cell lines. The RNA m6A methyltransferase METTL14 promotes the progression of NSCLC by targeted CSF1R.

Strategies for drug targeting in pancreatic cancer

BACKGROUND

Pancreatic cancer is expected to replace lung cancer as the second greatest cause of cancer mortality by 2025. It has been a particularly the most lethal kind of cancer.

OBJECTIVE

Despite the new innovations, research, and improvements in drug design; there are many hurdles limiting their therapeutic applications such as intrinsic resistance to chemotherapeutics, inability to deliver a sufficient concentration of drug to the target site, lack of effectiveness of drug delivery systems. These are the major contributing factors to limit the treatment. So, the main objective is to overcome these types of problems by nanotechnology and ligand conjugation approach to achieve targeted drug delivery.

METHOD

Nanotechnology has emerged as a major approach to develop cancer treatment. Regardless of the severity, there are several issues that restrict the therapeutic impact, including inadequate transport across biological barriers, limited cellular absorption, degradation, and faster clearance.

RESULT

Targeted drug delivery may overcome these obstacles by binding a natural ligand to the surface of nanocarriers, which enhances the drug's capacity to release at the desired site and minimizes adverse effects.

CONCLUSION

This study will investigate the possible outcomes of targeted therapeutic agent delivery in the treatment of pancreatic cancer, as well as the limitations and future prospects.

The role of N6-methyladenosine methylation in environmental exposure-induced health damage

The health risks caused by environmental pollution have long been of substantial concern. With the development of epigenetics, a large number of studies have demonstrated that N6-methyladenosine (m6A) modification is involved in the regulation of various important life activities associated with various diseases. Recent studies have revealed that m6A plays a key role in health damage caused by environmental exposure by regulating post-transcriptional gene expression. Therefore, our study outlined the effects of environmental pollutant exposure on m6A methylation and its regulator levels. Moreover, we found that m6A methylation modifications were involved in the development of various health damages by regulating important life activities in vivo, such as reactive oxygen species imbalance, apoptosis, epithelial-mesenchymal transition (EMT), and inflammatory processes. More importantly, we delved into the regulatory mechanisms of m6A methylation dysregulation in environmental pollution-induced diseases. Finally, by examining the published literature, we found that methyltransferase-like protein 3 (METTL3) and fat mass- and obesity-associated protein (FTO) were potentially used as biomarkers of health damage induced by particulate matter exposure and heavy metal exposure, respectively. The current studies on regulators of METTL3 and FTO were more promising to bring new perspectives for the treatment of environmental health-related diseases.

Emerging role of N6-methyladenosine RNA methylation in lung diseases

In recent years, with the increase of air pollution, smoking, aging, and respiratory infection, the incidence rate and mortality of lung diseases are increasing annually, which has become a major hazard to human health. N6-methyladenosine (m⁶A) RNA methylation is the most abundant modifications in eukaryotes, and such modified RNA can be specifically recognized and combined by m⁶A recognition proteins and then mediate RNA splicing, maturation, enucleation, degradation, and translation. More and more studies have revealed that the m⁶A modification is involved in the pathogenesis and development of some diseases; however, the mechanisms of m⁶A in lung diseases are poorly understood. In this review, we summarize the latest progress in the biological function of m⁶A modifications in lung diseases and discuss the potential therapeutic and prognostic strategies. The dysregulation of global m⁶A levels and m⁶A regulators may affect the occurrence and development of asthma, chronic obstructive pulmonary disease, lung cancer, and other lung diseases through inflammation and immune function. In lung cancer, this modification has an important impact on malignant cell proliferation, migration, invasion, and drug resistance. In addition, abnormally changed m⁶A-modified proteins in lung cancer tissue samples and circulating tumor cells (CTCs) may be used as diagnostic and prognostic markers of lung cancer. Models composed of multiple m⁶A regulators can be used to evaluate the risk prediction or prognosis of asthma and pulmonary fibrosis. In general, the in-depth study of m⁶A modifications is a frontier direction in disease research. It provides novel insights for understanding of the molecular mechanisms underlying disease occurrence, development, and drug resistance, as well as for the development of effective novel therapeutics.

N6-methyladenosine modification on Hmbox1 is related to telomere dysfunction in DEHP-induced male reproductive injury

AIMS

Di (2-ethylhexyl) phthalate (DEHP), as an environmental endocrine-disrupting chemical (EDC), can induce male reproductive injury. N6-methyladenosine (m6A) plays a vital role in environmental exposure-induced diseases by regulating gene expression. Therefore, we aim to investigate the role of m6A in DEHP-induced reproductive injury.

MAIN METHODS

We established an in vivo model of mice exposed to DEHP to explore the effect of DEHP on reproductive injury and m6A. To further explore the molecular mechanism of DEHP toxicity, we built a model of GC-2 cells exposed to mono-(2-ethylhexyl) phthalate (MEHP) in vitro and further silenced Mettl3 in GC-2cells. Besides, we also conducted MeRIP-qPCR and RIP assays to identify the target genes for m6A modification.

KEY FINDINGS

DEHP induced testicular injury and senescence. And telomeres shortening, reduced levels of telomere repeat-binding factor 1 (TRF1), TRF2, protection of telomeres 1 (POT1), and telomerase reverse transcriptase (TERT) can be observed in DEHP-treated testes. MEHP also induced GC-2 cellular senescence and telomere dysfunction. Besides, increased m6A mediated by METTL3 stabilized homeobox containing 1 (Hmbox1) in an m6A-dependent manner in MEHP-exposed GC-2 cells. Mettl3 knockdown led to lower m6A modification and reduced Hmbox1 stability, resulting in further shortening of telomere length.

SIGNIFICANCE

our work uncovered that DEHP led to male reproductive injury by telomere dysfunction and m6A modified Hmbox1 contributed to maintaining telomere homeostasis in this process, suggesting that accurate regulation of m6A modification level by drugs has potential value in the treatment of DEHP-induced male reproductive injury.

Investigation of the effects of downregulation of jumping translocation breakpoint (JTB) protein expression in MCF7 cells for potential use as a biomarker in breast cancer

MCF7 is a commonly used luminal type A non-invasive/poor-invasive human breast cancer cell line that does not usually migrate or invade compared with MDA-MB-231 highly metastatic cells, which emphasize an invasive and migratory behavior. Under special conditions, MCF7 cells might acquire invasive features. The aberration in expression and biological functions of the jumping translocation breackpoint (JTB) protein is associated with malignant transformation of cells, based on mitochondrial dysfunction, inhibition of tumor suppressive function of TGF-β, and involvement in cancer cell cycle. To investigate new putative functions of JTB by cellular proteomics, we analyzed the biological processes and pathways that are associated with the JTB protein downregulation. The results demonstrated that MCF7 cell line developed a more "aggressive" phenotype and behavior. Most of the proteins that were overexpressed in this experiment promoted the actin cytoskeleton reorganization that is involved in growth and metastatic dissemination of cancer cells. Some of these proteins are involved in the epithelial-mesenchymal transition (EMT) process (ACTBL2, TUBA4A, MYH14, CSPG5, PKM, UGDH, HSP90AA2, and MIF), in correlation with the energy metabolism reprogramming (PKM, UGDH), stress-response (HSP10, HSP70A1A, HSP90AA2), and immune and inflammatory response (MIF and ERp57-TAPBP). Almost all upregulated proteins in JTB downregulated condition promote viability, motility, proliferation, invasion, survival into a hostile microenvironment, metabolic reprogramming, and escaping of tumor cells from host immune control, leading to a more invasive phenotype for MCF7 cell line. Due to their downregulated condition, four proteins, such as CREBZF, KMT2B, SELENOS and CACNA1I are also involved in maintenance of the invasive phenotype of cancer cells, promoting cell proliferation, migration, invasion and tumorigenesis. Other downregulated proteins, such as MAZ, PLEKHG2, ENO1, TPI2, TOR2A, and CNNM1, may promote suppression of cancer cell growth, invasion, EMT, tumorigenic abilities, interacting with glucose and lipid metabolism, disrupting nuclear envelope stability, or suppressing apoptosis and developing anti-angiogenetic activities. Therefore, the main biological processes and pathways that may increase the tumorigenic potential of the MCF7 cells in JTB downregulated condition are related to the actin cytoskeleton organization, EMT, mitotic cell cycle, glycolysis and fatty acid metabolism, inflammatory response and macrophage activation, chemotaxis and migration, cellular response to stress condition (oxidative stress and hypoxia), transcription control, histone modification and ion transport.

Targeting RNA N6-methyladenosine modification: a precise weapon in overcoming tumor immune escape

Immunotherapy, especially immune checkpoint inhibitors (ICIs), has revolutionized the treatment of many types of cancer, particularly advanced-stage cancers. Nevertheless, although a subset of patients experiences dramatic and long-term disease regression in response to ICIs, most patients do not benefit from these treatments. Some may even experience cancer progression. Immune escape by tumor cells may be a key reason for this low response rate. N⁶-methyladenosine (m⁶A) is the most common type of RNA methylation and has been recognized as a critical regulator of tumors and the immune system. Therefore, m⁶A modification and related regulators are promising targets for improving the efficacy of tumor immunotherapy. However, the association between m⁶A modification and tumor immune escape (TIE) has not been comprehensively summarized. Therefore, this review summarizes the existing knowledge regarding m⁶A modifications involved in TIE and their potential mechanisms of action. Moreover, we provide an overview of currently available agents targeting m⁶A regulators that have been tested for their elevated effects on TIE. This review establishes the association between m⁶A modifications and TIE and provides new insights and strategies for maximizing the efficacy of immunotherapy by specifically targeting m⁶A modifications involved in TIE.

m6A RNA methylation regulates the transcription factors JUN and JUNB in TGF-β-induced epithelial-mesenchymal transition of lung cancer cells

N6-methyladenosine (m6A) is the most common internal chemical modification of mRNAs involved in many pathological processes including various cancers. In this study, we investigated the m6A-dependent regulation of JUN and JUNB transcription factors (TFs) during transforming growth factor-beta–induced epithelial–mesenchymal transition (EMT) of A549 and LC2/ad lung cancer cell lines, as the function and regulation of these TFs within this process remains to be clarified. We found that JUN and JUNB played an important and nonredundant role in the EMT-inducing gene expression program by regulating different mesenchymal genes and that their expressions were controlled by methyltransferase-like 3 (METTL3) m6A methyltransferase. METTL3–mediated regulation of JUN expression is associated with the translation process of JUN protein but not with the stability of JUN protein or mRNA, which is in contrast with the result of m6A-mediated regulation of JUNB mRNA stability. We identified the specific m6A motifs responsible for the regulation of JUN and JUNB in EMT within 3′UTR of JUN and JUNB. Furthermore, we discovered that different m6A reader proteins interacted with JUN and JUNB mRNA and controlled m6A-dependent expression of JUN protein and JUNB mRNA. These results demonstrate that the different modes of m6A-mediated regulation of JUN and JUNB TFs provide critical input in the gene regulatory network during transforming growth factor-beta–induced EMT of lung cancer cells.

Crosstalk between m6A regulators and mRNA during cancer progression

m⁶A modification, the most abundant and widespread RNA modification, is present and involved in the occurrence and development of various cancers. To date, most studies have mainly focused on the roles of a single m⁶A regulator (writer/eraser/reader) in various cancers, but cumulative evidence shows that aberrant m⁶A regulators and m⁶A levels exert dual effects (promoting and/or inhibiting roles) in cancer progression. Recently, studies have investigated the direct interactions between different m⁶A regulators (writer/eraser and reader) and mRNAs in a variety of cancers. In this review, we summarize the functions of m⁶A regulators and their roles in various types of cancers. We further propose the possible crosstalk mechanisms (Writer-m⁶A-Reader-mRNA axis and Eraser-m⁶A-Reader-mRNA axis) between different m⁶A regulators and mRNAs during cancer progression. We also discuss the clinical potential of m⁶A regulator‑targeting strategies.

Role of m6A writers, erasers and readers in cancer

The N(6)-methyladenosine (m6A) modification is the most pervasive modification of human RNAs. In recent years, an increasing number of studies have suggested that m6A likely plays important roles in cancers. Many studies have demonstrated that m6A is involved in the biological functions of cancer cells, such as proliferation, invasion, metastasis, and drug resistance. In addition, m6A is closely related to the prognosis of cancer patients. In this review, we highlight recent advances in understanding the function of m6A in various cancers. We emphasize the importance of m6A to cancer progression and look forward to describe future research directions.

METTL14-dependent m6A modification controls iNKT cell development and function

N⁶-methyladenosine (m⁶A), the most common form of RNA modification, controls CD4⁺ T cell homeostasis by targeting the IL-7/STAT5/SOCS signaling pathways. The role of m⁶A modification in unconventional T cell development remains unknown. Using mice with T cell-specific deletion of RNA methyltransferase METTL14 (T-Mettl14^−/−), we demonstrate that m⁶A modification is indispensable for iNKT cell homeostasis. Loss of METTL14-dependent m⁶A modification leads to the upregulation of apoptosis in double-positive thymocytes, which in turn decreases Vα14-Jα18 gene rearrangements, resulting in drastic reduction of iNKT numbers in the thymus and periphery. Residual T-Mettl14^−/− iNKT cells exhibit increased apoptosis, impaired maturation, and decreased responsiveness to IL-2/IL-15 and TCR stimulation. Furthermore, METTL14 knockdown in mature iNKT cells diminishes their cytokine production, correlating with increased Cish expression and decreased TCR signaling. Collectively, our study highlights a critical role for METTL14-dependent-m⁶A modification in iNKT cell development and function.

Cao et al. show that T cell-specific deletion of METTL14, a component of RNA m⁶A writer complex, leads to severe defects in iNKT cell development, survival, and function. Mechanistically, METTL14-dependent m⁶A modification controls iNKT cell development in a cell-intrinsic manner by regulating the apoptosis pathway and TCR signaling pathway.

Multifaceted Roles of the N6-Methyladenosine RNA Methyltransferase METTL3 in Cancer and Immune Microenvironment

As the most abundant internal mRNA modification in eukaryotic cells, N⁶-methyladenosine (m⁶A) has emerged as an important regulator of gene expression and has a profound impact on cancer initiation and progression. mRNA m⁶A modification is regulated by m⁶A methyltransferases, demethylases and reader proteins to fine tune gene expression at the post-transcriptional level. The most well-studied m⁶A methyltransferase, METTL3, plays critical roles in regulating gene expression and affecting the outcome of various cancers. In this review, we discuss the multifaceted roles of METTL3 in regulating specific molecular signaling pathways in different types of cancers and the recent progress on how METTL3 impacts the tumor immune microenvironment. Finally, we discuss future directions and the potential for therapeutic targeting of METTL3 in cancer treatment.

METTL3-Mediated m6A RNA Methylation of ZBTB4 Interferes With Trophoblast Invasion and Maybe Involved in RSA

N⁶-methyladenosine (m⁶A) was the most abundant modification of mRNA and lncRNA in mammalian cells and played an important role in many biological processes. However, whether m⁶A modification was associated with recurrent spontaneous abortion (RSA) and its roles were still unclear.

Methods: Methylated RNA immunoprecipitation sequencing (MeRIP-Seq) was used to study the global m⁶A modification pattern in RSAs and controls. RNA sequencing (RNA-Seq) was used to study the level of global mRNA in two groups. Real-time quantitative PCR (RT-qPCR) was used to verify the level of mRNA of METTL3 and ZBTB4. MeRIP–qPCR was conducted to test the level of ZBTB4 m⁶A modification in two groups. In order to further explore whether ZBTB4 was the substrate of METTL3, the HTR-8/SVneo (HTR-8) cell line was selected for the knockdown and overexpression of METTL3. To study whether METTL3 regulated the ZBTB4 expression by recognizing ZBTB4 mRNA m⁶A motifs in coding sequences (CDS), dual-luciferase reporter assay was conducted. RNA stability assays using actinomycin D were conducted to study the RNA stability of the HTR-8 cell line with METTL3 overexpression and knockdown. To illustrate the role of METTL3 in the invasion of trophoblast, matrigel invasion assays and transwell migration assays were conducted using the HTR-8 cell line with METTL3 overexpression and knockdown.

Results: A total of 65 genes were found with significant differences both in m⁶A modification and mRNA expression. We found m⁶A methyltransferase METTL3 was significantly down-regulated in the RSA group. Through gene function analysis, RT-qPCR, MeRIP–qPCR validation experiment, knockdown, and overexpression of METTL3 in the HTR-8 cell line, ZBTB4 was selected as one target of METTL3. Furthermore, we clarified that METTL3 regulated the expression of ZBTB4 by recognizing ZBTB4 mRNA m⁶A motifs in the CDS using the dual-luciferase reporter assay and METTL3 regulated the invasion of trophoblast by altering the stability and expression of ZBTB4 by RNA stability, matrigel invasion, and transwell migration assays.

Conclusion: Our study revealed the mechanism by which METTL3 regulated the stability and expression of ZBTB4 and the trophoblast migration ability of RSA. A new perspective was provided for exploring the mechanism of embryonic development in RSA patients.

M6A-Related Bioinformatics Analysis Reveals a New Prognostic Risk Signature in Cutaneous Malignant Melanoma

Cutaneous malignant melanoma (CMM) is the most deadly skin cancer worldwide. Despite advances in the treatments of CMM, its incidence and mortality rates are still increasing. N6-methyladenosine (m6A) is the most common form of RNA modification and has attracted increasing interest in cancer initiation and progression. However, the role of m6A regulators in CMM and their correlation with prognosis remain elusive. Here, we demonstrated that by applying consensus clustering, all CMM patient cases can be divided into two clusters based on overall expression levels of 25 m6A genes. We systematically analyzed the prognostic value of the 25 m6A RNA methylation regulators in CMM and found that ELAVL1, ABCF1, and IGF2BP1 yield the highest scores for predicting the prognosis of CMM. Accordingly, we derived a risk signature consisting of three selected m6A genes as an independent prognostic marker for CMM and validated our findings with data derived from a different CMM cohort. Next, we determined that CNVs in m6A genes had a significant negative impact on patient survival. The mRNA expression levels of m6A genes were correlated with CNV mutation. Moreover, in the selected three risk signature m6A regulators, GSEA analysis showed that they were closely correlated with inflammation and immune pathways. TME analysis proved that m6A gene expressions were negatively correlated with immune cell infiltration. In conclusion, m6A regulators are vital participants in CMM pathology; and ELAVL1, ABCF1, and IGF2BP1 mRNA levels are valuable factors for prognosis prediction and treatment strategy development.

The molecular mechanism of METTL3 promoting the malignant progression of lung cancer

Lung cancer remains one of the major causes of cancer-related death globally. Recent studies have shown that aberrant m⁶A levels caused by METTL3 are involved in the malignant progression of various tumors, including lung cancer. The m⁶A modification, the most abundant RNA chemical modification, regulates RNA stabilization, splicing, translation, decay, and nuclear export. The methyltransferase complex plays a key role in the occurrence and development of many tumors by installing m⁶A modification. In this complex, METTL3 is the first identified methyltransferase, which is also the major catalytic enzyme. Recent findings have revealed that METTL3 is remarkably associated with different aspects of lung cancer progression, influencing the prognosis of patients. In this review, we will focus on the underlying mechanism of METT3 in lung cancer and predict the future work and potential clinical application of targeting METTL3 for lung cancer therapy.

Mutant NPM1-Regulated FTO-Mediated m6A Demethylation Promotes Leukemic Cell Survival via PDGFRB/ERK Signaling Axis

Acute myeloid leukemia (AML) with nucleophosmin 1 (NPM1) mutations exhibits distinct biological and clinical features, accounting for approximately one-third of AML. Recently, the N⁶-methyladenosine (m⁶A) RNA modification has emerged as a new epigenetic modification to contribute to tumorigenesis and development. However, there is limited knowledge on the role of m⁶A modifications in NPM1-mutated AML. In this study, the decreased m⁶A level was first detected and high expression of fat mass and obesity-associated protein (FTO) was responsible for the m⁶A suppression in NPM1-mutated AML. FTO upregulation was partially induced by NPM1 mutation type A (NPM1-mA) through impeding the proteasome pathway. Importantly, FTO promoted leukemic cell survival by facilitating cell cycle and inhibiting cell apoptosis. Mechanistic investigations demonstrated that FTO depended on its m⁶A RNA demethylase activity to activate PDGFRB/ERK signaling axis. Our findings indicate that FTO-mediated m⁶A demethylation plays an oncogenic role in NPM1-mutated AML and provide a new layer of epigenetic insight for future treatments of this distinctly leukemic entity.

The essential roles of m6A RNA modification to stimulate ENO1-dependent glycolysis and tumorigenesis in lung adenocarcinoma

Background

Lung adenocarcinoma (LUAD)  is the most common subtype of lung cancer. Patient prognosis is poor, and the existing therapeutic strategies for LUAD are far from satisfactory. Recently, targeting N6-methyladenosine (m⁶A) modification of RNA has been suggested as a potential strategy to impede tumor progression. However, the roles of m⁶A modification in LUAD tumorigenesis is unknown.

Methods

Global m⁶A levels and expressions of m⁶A writers, erasers and readers were evaluated by RNA methylation assay, dot blot, immunoblotting, immunohistochemistry and ELISA in human LUAD, mouse models and cell lines. Cell viability, 3D-spheroid generation, in vivo LUAD formation, experiments in cell- and patient-derived xenograft mice and survival analysis were conducted to explore the impact of m⁶A on LUAD. The RNA-protein interactions, translation, putative m⁶A sites and glycolysis were explored in the investigation of the mechanism underlying how m⁶A stimulates tumorigenesis.

Results

The elevation of global m⁶A level in most human LUAD specimens resulted from the combined upregulation of m⁶A writer methyltransferase 3 (METTL3) and downregulation of eraser alkB homolog 5 (ALKBH5). Elevated global m⁶A level was associated with a poor overall survival in LUAD patients. Reducing m⁶A levels by knocking out METTL3 and overexpressing ALKBH5 suppressed 3D-spheroid generation in LUAD cells and intra-pulmonary tumor formation in mice. Mechanistically, m⁶A-dependent stimulation of glycolysis and tumorigenesis occurred via enolase 1 (ENO1). ENO1 mRNA was m⁶A methylated at 359 A, which facilitated it’s binding with the m⁶A reader YTH N6-methyladenosine RNA binding protein 1 (YTHDF1) and resulted in enhanced translation of ENO1. ENO1 positively correlated with METTL3 and global m⁶A levels, and negatively correlated with ALKBH5 in human LUAD. In addition, m⁶A-dependent elevation of ENO1 was associated with LUAD progression. In preclinical models, tumors with a higher global m⁶A level showed a more sensitive response to the inhibition of pan-methylation, glycolysis and ENO activity in LUAD.

Conclusions

The m⁶A-dependent stimulation of glycolysis and tumorigenesis in LUAD is at least partially orchestrated by the upregulation of METTL3, downregulation of ALKBH5, and stimulation of YTHDF1-mediated ENO1 translation. Blocking this mechanism may represent a potential treatment strategy for m⁶A-dependent LUAD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-02200-5.

The unfavorable clinical outcome of COVID-19 in smokers is mediated by H3K4me3, H3K9me3 and H3K27me3 histone marks

Smoking could predispose individuals to a more severe COVID-19 by upregulating a particular gene known as mdig, which is mediated through a number of well-known histone modifications. Smoking might regulate the transcription-activating H3K4me3 mark, along with the transcription-repressing H3K9me3 and H3K27me3 marks, in a way to favor SARS-CoV-2 entry by enhancing the expression of ACE2, NRP1 and NRP2, AT1R, CTSD and CTSL, PGE2 receptors 2-4, SLC6A20 and IL-6, all of which interact either directly or indirectly with important receptors, facilitating viral entry in COVID-19.

m6A Modification Patterns With Distinct Immunity, Metabolism, and Stemness Characteristics in Soft Tissue Sarcoma

N6-methyladenosine (m6A) RNA methylation has been shown to have prognostic value in cancer. Nonetheless, its potential role regarding immunity, metabolism, and stemness in soft tissue sarcoma (STS) remains unknown. We comprehensively estimated the m6A modification patterns and corresponding immunity, metabolism, and stemness characteristics based on 568 STS samples and 21 m6A regulators. The m6Ascore was constructed to quantify m6A modification patterns in individuals using machine learning algorithms. Two distinct m6A modification patterns among the STS patients were identified, which exhibited differences in prognosis, immune cell infiltration, metabolic pathways, stemness, somatic mutation, and copy number variation. Thereafter, immunity-, metabolism-, and stemness phenotype-related genes associated with m6A modification were identified. Furthermore, patients with lower m6Ascores had increased antitumor immune responses, survival benefit under immunotherapy, tumor mutation burden, immunogenicity, and response to anti-PD-1/L1 immunotherapy. Immunotherapy sensitivity was validated using the IMvigor210 dataset. STS patients with lower m6Ascore might be more sensitive to docetaxel and gemcitabine. Finally, pan-cancer analysis illustrated the significant correlations of m6Ascore with clinical outcomes, immune cell infiltration, metabolism, and stemness. This study revealed that m6A modification plays an important role in immunity, metabolism, and stemness in STS. Evaluating the m6A modification pattern and development of m6Ascore may help to guide more effective immunotherapy and chemotherapy strategies.

Mechanism of methyltransferase like 3 in epithelial-mesenchymal transition process, invasion, and metastasis in esophageal cancer

Methyltransferase like 3 (METTL3) has been identified to serve as a definitive inducer in cancer progression. This study sought to analyze the regulatory mechanism of METTL3 in epithelial-mesenchymal transition (EMT), invasion, and metastasis in esophageal cancer (ESCA). The METTL3 expressions in cancer tissues and cells were detected with extensive analysis of its correlation with clinical baseline data. The cells were transfected with sh-RNA-METTL3 and microRNA (miR)-20a-5p mimic, followed by evaluation of invasion, migration, and EMT. The N6-methyladenosine (m6A) level and enrichment of DiGeorge Critical Region 8 (DGCR8) and m6A were observed. The binding relationship between miR-20a-5p and Nuclear Factor I-C (NFIC) was verified, followed by Pearson correlation analysis. A subcutaneous tumor formation assay was conducted prior to observation of lung metastases. Our results revealed that METTL3 was highly expressed in ESCA patients and associated with severe lymph node involvement and distant metastasis. METTL3 downregulation radically inhibited the invasiveness, migration, and EMT. METTL3 elevated the miR-20a-5p expression via improving m6A modification. METTL3 inhibition downregulated the miR-20a-5p expression. Moreover, miR-20a-5p upregulation facilitated ESCA cell invasiveness and migration by targeting NFIC transcription. METTL3 inhibition suppressed tumor growth and lung metastasis in vivo. Overall, METTL3 promoted m6A modification and the binding of DGCR8 to miR-20a-5p to further elevate the miR-20a-5p expression and inhibit NFIC transcription, thus promoting EMT, invasion and migration.

N6-methyladenosine modification of CDH1 mRNA promotes PM2.5-induced pulmonary fibrosis via mediating epithelial mesenchymal transition

The association between ambient airborne fine particulate matter (PM2.5) exposure and respiratory diseases has been investigated in epidemiological studies. To explore the potential mechanism of PM2.5-induced pulmonary fibrosis, sixty mice were divided into 3 groups to expose to different levels of PM2.5 for 8 and 16 weeks: filtered air (FA), unfiltered air (UA) and concentrated PM2.5 air (CA), respectively. BEAS-2B cells were treated with 0, 25, 50 and 100 μg/ml PM2.5 for 24 h. The biomarkers of pulmonary fibrosis, epithelial-mesenchymal transition (EMT), N6-methyladenosine (m6A) modification and metabolism of mRNAs were detected to characterize the effect of PM2.5 exposure. The results illustrated that PM2.5 exposure induced pathological alteration and pulmonary fibrosis in mice. The expression of E-cadherin (E-cad) was decreased whereas vimentin and N-cadherin (N-cad) expression were increased in a dose- and time-dependent manner after PM2.5 exposure. Mechanistically, PM2.5 exposure increased the levels of METTL3-mediated m6A modification of CDH1 mRNA. As a target gene of miR-494-3p, YTHDF2 was up-regulated by miR-494-3p down-regulation and then recognized m6A-modified CDH1 mRNA to inhibit the E-cad expression, consequently induced the EMT progression after PM2.5 exposure. Our study indicated that PM2.5 exposure triggered EMT progression to promote the pulmonary fibrosis via miR-494-3p/YTHDF2 recognized and METTL3 mediated m6A modification.

Cigarette smoking induces aberrant N6-methyladenosine of DAPK2 to promote non-small cell lung cancer progression by activating NF-κB pathway

N6-methyladenosine (m6A) has recently emerged as an important regulatory mechanism for gene expression and aberrant m6A modification plays an important role in tumor progression. Emerging evidence has shown that aberrant m6A modification induced by cigarette smoking is involved in carcinogenesis, but whether cigarette smoking affects m6A modification and thus deteriorates to non-small cell lung cancer (NSCLC) is still unclear. Here, we identified a tumor suppressor gene-DAPK2 which was significantly associated with poor prognosis of NSCLC patients, especially in patients with a smoking history. Low levels of DAPK2 were detected in smokers and in NSCLC tissues. Cigarette smoking induced aberrant N6-methyladenosine modification of DAPK2, which resulted in decreased DAPK2 mRNA stability and expression of its mRNA and protein. This modification was mediated by the m6A "writer" METTL3 and the m6A "reader" YTHDF2. Mechanistically, we further demonstrated that DAPK2 functions as a tumor suppressor and downregulation of DAPK2 substantially enhances the proliferation and migration abilities in vitro and in vivo by activating NF-κB signaling pathway. Notably, the BAY 11-7085, a NF-κB signaling selective inhibitor, was shown to efficiently suppressed downregulation of DAPK2-induced oncogenic phenotypes of NSCLC cells. Our study reveals that cigarette smoking induces aberrant N6-methyladenosine of DAPK2 to promote NSCLC progression, which provides new insight into the mechanisms of NSCLC progression and a specific therapeutic target for NSCLC patients with a smoking history.

The Role of m6A Ribonucleic Acid Modification in the Occurrence of Atherosclerosis

The N6-methyladenosine (m6A) modification is the most abundant epitranscriptomic modification in eukaryotic messenger RNA (mRNA). The m6A modification process is jointly regulated by various enzymes and proteins, such as methyltransferases, demethylases and related m6A-binding proteins. The process is dynamic and reversible, and it plays an essential role in mRNA metabolism and various biological activities. Recently, an increasing number of researchers have confirmed that the onset and development of many diseases are closely associated with the molecular biological mechanism of m6A RNA methylation. This study focuses on the relationship between m6A RNA modification and atherosclerosis (AS). It thoroughly summarizes the mechanisms and processes of m6A RNA modification in AS-related cells and the relationships between m6A RNA modification and AS risk factors, and it provides a reference for exploring new targets for the early diagnosis and treatment of AS.

m6A modification of RNA and its role in cancer, with a special focus on lung cancer

Epitranscriptomics involves functionally relevant biochemical modifications of RNA taking place at the transcriptome level without a change in the sequence of ribonucleotides. Several types of modifications that affect the processing and function of differentRNA types have been reported. Methylation at N₆ of Adenosine called m⁶A is one such modification, quite widespread in occurrence and reported in snRNAs, lncRNAs, circRNAs, rRNAs, miRNAs, and most abundantly, in mRNAs. The significant implications of m⁶A in various types of cancers are being widely recognized. Here, we give a brief about the enzymes that install the m⁶A modification (= m⁶A writers), that remove it (= m⁶A erasers) and certain RNA binding proteins (= m⁶A readers) which affect the fate of the m⁶A-containing RNA by recruiting various proteins. We also discuss the relevance of m⁶A in ncRNAs in various cancer types, followed by a discussion on the role of m⁶A of mRNA and ncRNA in lung cancer.

N6-methyladenosine-dependent signalling in cancer progression and insights into cancer therapies

The N6-methyladenosine (m6A) modification is a dynamic and reversible epigenetic modification, which is co-transcriptionally deposited by a methyltransferase complex, removed by a demethylase, and recognized by reader proteins. Mechanistically, m6A modification regulates the expression levels of mRNA and nocoding RNA by modulating the fate of modified RNA molecules, such as RNA splicing, nuclear transport, translation, and stability. Several studies have shown that m6A modification is dysregulated in the progression of multiple diseases, especially human tumors. We emphasized that the dysregulation of m6A modification affects different signal transduction pathways and involves in the biological processes underlying tumor cell proliferation, apoptosis, invasion and migration, and metabolic reprogramming, and discuss the effects on different cancer treatment.