m6A methylation: a process reshaping the tumour immune microenvironment and regulating immune evasion

Reprogramming exosomes for immunity-remodeled photodynamic therapy against non-small cell lung cancer

Traditional treatments against advanced non-small cell lung cancer (NSCLC) with high morbidity and mortality continue to be dissatisfactory. Given this situation, there is an urgent requirement for alternative modalities that provide lower invasiveness, superior clinical effectiveness, and minimal adverse effects. The combination of photodynamic therapy (PDT) and immunotherapy gradually become a promising approach for high-grade malignant NSCLC. Nevertheless, owing to the absence of precise drug delivery techniques as well as the hypoxic and immunosuppressive characteristics of the tumor microenvironment (TME), the efficacy of this combination therapy approach is less than ideal. In this study, we construct a novel nanoplatform that indocyanine green (ICG), a photosensitizer, loads into hollow manganese dioxide (MnO2) nanospheres (NPs) (ICG@MnO2), and then encapsulated in PD-L1 monoclonal antibodies (anti-PD-L1) reprogrammed exosomes (named ICG@MnO2@Exo-anti-PD-L1), to effectively modulate the TME to oppose NSCLC by the synergy of PDT and immunotherapy modalities. The ICG@MnO2@Exo-anti-PD-L1 NPs are precisely delivered to the tumor sites by targeting specially PD-L1 highly expressed cancer cells to controllably release anti-PD-L1 in the acidic TME, thereby activating T cell response. Subsequently, upon endocytic uptake by cancer cells, MnO2 catalyzes the conversion of H2O2 to O2, thereby alleviating tumor hypoxia. Meanwhile, ICG further utilizes O2 to produce singlet oxygen (1O2) to kill tumor cells under 808 nm near-infrared (NIR) irradiation. Furthermore, a high level of intratumoral H2O2 reduces MnO2 to Mn2+, which remodels the immune microenvironment by polarizing macrophages from M2 to M1, further driving T cells. Taken together, the current study suggests that the ICG@MnO2@Exo-anti-PD-L1 NPs could act as a novel drug delivery platform for achieving multimodal therapy in treating NSCLC.

RNA M6A modification shaping cutaneous melanoma tumor microenvironment and predicting immunotherapy response

Recent years have seen rising mortality rates linked to cutaneous melanoma (SKCM), despite advances in immunotherapy. Understanding RNA N6-methyladenosine (M6A) significance in SKCM is crucial for prognosis, tumor microenvironment (TME), immune cell presence, and immunotherapy efficacy. We analyzed 23 M6A regulators using SKCM samples from TCGA and GEO databases, identifying three M6A modification patterns linked to TME cell infiltration. Principal component analysis (PCA) yielded an M6A score for individual tumors, utilizing patient gene expression profiles and CNV data from TCGA. M6A modification patterns play a crucial role in SKCM development and progression, influencing tumor attributes such as inflammatory stage, subtype, TME interstitial activity, and genetic mutations. The M6A score independently predicts patient outcomes and correlates with improved response to immunotherapy, validated across anti-PD-1 and anti-PD-L1 therapy cohorts. M6A modifications significantly impact the TME landscape, with the M6A score serving as a predictive marker for immunotherapy response. Integrating M6A-related information into clinical practice could revolutionize SKCM management and treatment strategies.

Influence of METTL3 knockdown on PDLSC osteogenesis in E. coli LPS-induced inflammation

OBJECTIVE

This study aimed to investigate the effect of METTL3 knockdown on osteogenic differentiation of human periodontal ligament stem cells (PDLSCs) in the weak inflammation microenvironments, as well as the underlying mechanisms.

MATERIALS AND METHODS

PDLSCs were stimulated by lipopolysaccharide from Escherichia coli (E. coli LPS), followed by quantification of METTL3. METTL3 expression was assessed using RT-qPCR and Western blot analysis in periodontitis. METTL3 knockdown PDLSCs were stimulated with or without E. coli LPS. The evaluation included proinflammatory cytokines, osteogenic markers, ALP activity, and mineralized nodules. Bioinformatics analysis and Western blot determined the association between METTL3 and the PI3K/Akt pathway.

RESULTS

METTL3 was overexpressed in periodontitis. METTL3 knockdown in PDLSCs reduced proinflammatory cytokines, osteogenic markers, ALP activity, and mineralized nodules in both environments. Bioinformatics analysis suggested a link between METTL3 and the PI3K/Akt pathway. METTL3 knockdown inhibited PI3K/Akt signaling pathway activation.

CONCLUSION

METTL3 knockdown might inhibit osteogenesis in PDLSCs through the inactivation of PI3K/Akt signaling pathway. Concomitant findings might shed novel light on the roles and potential mechanisms of METTL3 in the LPS-stimulated inflammatory microenvironments of PDLSCs.

METTL3-mediated N6-methyladenosine modification of STAT5A promotes gastric cancer progression by regulating KLF4

N6-methyladenosine (m6A) is the predominant post-transcriptional RNA modification in eukaryotes and plays a pivotal regulatory role in various aspects of RNA fate determination, such as mRNA stability, alternative splicing, and translation. Dysregulation of the critical m6A methyltransferase METTL3 is implicated in tumorigenesis and development. Here, this work showed that METTL3 is upregulated in gastric cancer tissues and is associated with poor prognosis. METTL3 methylates the A2318 site within the coding sequence (CDS) region of STAT5A. IGF2BP2 recognizes and binds METTL3-mediated m6A modification of STAT5A through its GXXG motif in the KH3 and KH4 domains, leading to increased stability of STAT5A mRNA. In addition, both METTL3 and IGF2BP2 are positively correlated with STAT5A in human gastric cancer tissue samples. Helicobacter pylori infection increased the expression level of METTL3 in gastric cancer cells, thereby leading to the upregulation of STAT5A. Functional studies indicated that STAT5A overexpression markedly enhances the proliferation and migration of GC cells, whereas STAT5A knockdown has inhibitory effects. Further nude mouse experiments showed that STAT5A knockdown effectively inhibits the growth and metastasis of gastric cancer in vivo. Moreover, as a transcription factor, STAT5A represses KLF4 transcription by binding to its promoter region. The overexpression of KLF4 can counteract the oncogenic impact of STAT5A. Overall, this study highlights the crucial role of m6A in gastric cancer and provides potential therapeutic targets for gastric cancer.

PD-L1 at the crossroad between RNA metabolism and immunosuppression

Programmed death ligand-1 (PD-L1) is a key component of tumor immunosuppression. The uneven therapeutic results of PD-L1 therapy have stimulated intensive studies to better understand the mechanisms underlying altered PD-L1 expression in cancer cells, and to determine whether, beyond its immune function, PD-L1 might have intracellular functions promoting tumor progression and resistance to treatments. In this Opinion, we focus on paradigmatic examples highlighting the central role of PD-L1 in post-transcriptional regulation, with PD-L1 being both a target and an effector of molecular mechanisms featured prominently in RNA research, such as RNA methylation, phase separation and RNA G-quadruplex structures, in order to highlight vulnerabilities on which future anti-PD-L1 therapies could be built.

The role of RNA methylation in tumor immunity and its potential in immunotherapy

RNA methylation, a prevalent post-transcriptional modification, has garnered considerable attention in research circles. It exerts regulatory control over diverse biological functions by modulating RNA splicing, translation, transport, and stability. Notably, studies have illuminated the substantial impact of RNA methylation on tumor immunity. The primary types of RNA methylation encompass N6-methyladenosine (m6A), 5-methylcytosine (m5C), N1-methyladenosine (m1A), and N7-methylguanosine (m7G), and 3-methylcytidine (m3C). Compelling evidence underscores the involvement of RNA methylation in regulating the tumor microenvironment (TME). By affecting RNA translation and stability through the "writers", "erasers" and "readers", RNA methylation exerts influence over the dysregulation of immune cells and immune factors. Consequently, RNA methylation plays a pivotal role in modulating tumor immunity and mediating various biological behaviors, encompassing proliferation, invasion, metastasis, etc. In this review, we discussed the mechanisms and functions of several RNA methylations, providing a comprehensive overview of their biological roles and underlying mechanisms within the tumor microenvironment and among immunocytes. By exploring how these RNA modifications mediate tumor immune evasion, we also examine their potential applications in immunotherapy. This review aims to provide novel insights and strategies for identifying novel targets in RNA methylation and advancing cancer immunotherapy efficacy.

ALKBH5 promotes non-small cell lung cancer progression and susceptibility to anti-PD-L1 therapy by modulating interactions between tumor and macrophages

BACKGROUND

Understanding the mechanisms that mediate the interaction between tumor and immune cells may provide therapeutic benefit to patients with cancer. The N6-methyladenosine (m6A) demethylase, ALKBH5 (alkB homolog 5), is overexpressed in non-small cell lung cancer. However, its role in the tumor microenvironment is unknown.

METHODS

Datasets and tissue samples were used to determine the relationship between ALKBH5 expression and immunotherapy efficacy. Bioinformatic analysis, colorimetric assay to determine m6A RNA methylation, dual luciferase reporter assay, RNA/m6A-modified RNA immunoprecipitation, RNA stability assay, and RNA sequencing were used to investigate the regulatory mechanism of ALKBH5 in non-small cell lung cancer. In vitro and in vivo assays were performed to determine the contribution of ALKBH5 to the development of non-small cell lung cancer.

RESULTS

ALKBH5 was upregulated in primary non-small cell lung cancer tissues. ALKBH5 was positively correlated with programmed death-ligand 1 expression and macrophage infiltration and was associated with immunotherapy response. JAK2 was identified as a target of ALKBH5-mediated m6A modification, which activates the JAK2/p-STAT3 pathway to promote non-small cell lung cancer progression. ALKBH5 was found to recruit programmed death-ligand 1-positive tumor-associated macrophages and promote M2 macrophage polarization by inducing the secretion of CCL2 and CXCL10. ALKBH5 and tumor-associated macrophage-secreted IL-6 showed a synergistic effect to activate the JAK2/p-STAT3 pathway in cancer cells.

CONCLUSIONS

ALKBH5 promotes non-small cell lung cancer progression by regulating cancer and tumor-associated macrophage behavior through the JAK2/p-STAT3 pathway and the expression of CCL2 and CXCL10, respectively. These findings suggest that targeting ALKBH5 is a promising strategy of enhancing the anti-tumor immune response in patients with NSCLC and that identifying ALKBH5 status could facilitate prediction of clinical response to anti-PD-L1 immunotherapy.

Identification of potential novel N6-methyladenosine effector-related lncRNA biomarkers for serous ovarian carcinoma: a machine learning-based exploration in the framework of 3P medicine

Background

Serous ovarian carcinoma (SOC) is considered the most lethal gynecological malignancy. The current lack of reliable prognostic biomarkers for SOC reduces the efficacy of predictive, preventive, and personalized medicine (PPPM/3PM) in patients with SOC, leading to unsatisfactory therapeutic outcomes. N6-methyladenosine (m6A) modification-associated long noncoding RNAs (lncRNAs) are effective predictors of SOC. In this study, an effective risk prediction model for SOC was constructed based on m6A modification-associated lncRNAs.

Methods

Transcriptomic data and clinical information of patients with SOC were downloaded from The Cancer Genome Atlas. Candidate lncRNAs were identified using univariate and multivariate and least absolute shrinkage and selection operator-penalized Cox regression analyses. The molecular mechanisms of m6A effector-related lncRNAs were explored via Gene Ontology, pathway analysis, gene set enrichment analysis, and gene set variation analysis (GSVA). The extent of immune cell infiltration was assessed using various algorithms, including CIBERSORT, Microenvironment Cell Populations counter, xCell, European Prospective Investigation into Cancer and Nutrition, and GSVA. The calcPhenotype algorithm was used to predict responses to the drugs commonly used in ovarian carcinoma therapy. In vitro experiments, such as migration and invasion Transwell assays, wound healing assays, and dot blot assays, were conducted to elucidate the functional roles of candidate lncRNAs.

Results

Six m6A effector-related lncRNAs that were markedly associated with prognosis were used to establish an m6A effector-related lncRNA risk model (m6A-LRM) for SOC. Immune microenvironment analysis suggested that the high-risk group exhibited a proinflammatory state and displayed increased sensitivity to immunotherapy. A nomogram was constructed with the m6A effector-related lncRNAs to assess the prognostic value of the model. Sixteen drugs potentially targeting m6A effector-related lncRNAs were identified. Furthermore, we developed an online web application for clinicians and researchers (https://leley.shinyapps.io/OC_m6A_lnc/). Overexpression of the lncRNA RP11-508M8.1 promoted SOC cell migration and invasion. METTL3 is an upstream regulator of RP11-508M8.1. The preliminary regulatory axis METTL3/m6A/RP11-508M8.1/hsa-miR-1270/ARSD underlying SOC was identified via a combination of in vitro and bioinformatic analyses.

Conclusion

In this study, we propose an innovative prognostic risk model and provide novel insights into the mechanism underlying the role of m6A-related lncRNAs in SOC. Incorporating the m6A-LRM into PPPM may help identify high-risk patients and personalize treatment as early as possible.

Development of pharmacological immunoregulatory anti-cancer therapeutics: current mechanistic studies and clinical opportunities

Immunotherapy represented by anti-PD-(L)1 and anti-CTLA-4 inhibitors has revolutionized cancer treatment, but challenges related to resistance and toxicity still remain. Due to the advancement of immuno-oncology, an increasing number of novel immunoregulatory targets and mechanisms are being revealed, with relevant therapies promising to improve clinical immunotherapy in the foreseeable future. Therefore, comprehending the larger picture is important. In this review, we analyze and summarize the current landscape of preclinical and translational mechanistic research, drug development, and clinical trials that brought about next-generation pharmacological immunoregulatory anti-cancer agents and drug candidates beyond classical immune checkpoint inhibitors. Along with further clarification of cancer immunobiology and advances in antibody engineering, agents targeting additional inhibitory immune checkpoints, including LAG-3, TIM-3, TIGIT, CD47, and B7 family members are becoming an important part of cancer immunotherapy research and discovery, as are structurally and functionally optimized novel anti-PD-(L)1 and anti-CTLA-4 agents and agonists of co-stimulatory molecules of T cells. Exemplified by bispecific T cell engagers, newly emerging bi-specific and multi-specific antibodies targeting immunoregulatory molecules can provide considerable clinical benefits. Next-generation agents also include immune epigenetic drugs and cytokine-based therapeutics. Cell therapies, cancer vaccines, and oncolytic viruses are not covered in this review. This comprehensive review might aid in further development and the fastest possible clinical adoption of effective immuno-oncology modalities for the benefit of patients.

The role of tumor-associated macrophages in tumor immune evasion

BACKGROUND

Tumor growth is closely linked to the activities of various cells in the tumor microenvironment (TME), particularly immune cells. During tumor progression, circulating monocytes and macrophages are recruited, altering the TME and accelerating growth. These macrophages adjust their functions in response to signals from tumor and stromal cells. Tumor-associated macrophages (TAMs), similar to M2 macrophages, are key regulators in the TME.

METHODS

We review the origins, characteristics, and functions of TAMs within the TME. This analysis includes the mechanisms through which TAMs facilitate immune evasion and promote tumor metastasis. Additionally, we explore potential therapeutic strategies that target TAMs.

RESULTS

TAMs are instrumental in mediating tumor immune evasion and malignant behaviors. They release cytokines that inhibit effector immune cells and attract additional immunosuppressive cells to the TME. TAMs primarily target effector T cells, inducing exhaustion directly, influencing activity indirectly through cellular interactions, or suppressing through immune checkpoints. Additionally, TAMs are directly involved in tumor proliferation, angiogenesis, invasion, and metastasis. Developing innovative tumor-targeted therapies and immunotherapeutic strategies is currently a promising focus in oncology. Given the pivotal role of TAMs in immune evasion, several therapeutic approaches have been devised to target them. These include leveraging epigenetics, metabolic reprogramming, and cellular engineering to repolarize TAMs, inhibiting their recruitment and activity, and using TAMs as drug delivery vehicles. Although some of these strategies remain distant from clinical application, we believe that future therapies targeting TAMs will offer significant benefits to cancer patients.

The identification of a N6-methyladenosin-modifed immune pattern to predict immunotherapy response and survival in urothelial carcinoma

BACKGROUND

Dysregulation of the immune system and N6-methyladenosine (m6A) contribute to immune therapy resistance and cancer progression in urothelial carcinoma (UC). This study aims to identify immune-related molecules, that are m6A-modified, and that are associated with tumor progression, poor prognosis, and immunotherapy response.

METHODS

We identified prognostic immune genes (PIGs) using Cox analysis and random survival forest variable hunting algorithm (RSF-VH) on immune genes retrieved from the Immunology Database and Analysis Portal database (ImmPort). The RM2Target database and MeRIP-seq analysis, combined with a hypergeometric test, assessed m6A methylation in these PIGs. We analyzed the correlation between the immune pattern and prognosis, as well as their association with clinical factors in multiple datasets. Moreover, we explored the interplay between immune patterns, tumor immune cell infiltration, and m6A regulators.

RESULTS

28 PIGs were identified, of which the 10 most significant were termed methylated prognostic immune genes (MPIGs). These MPIGs were used to create an immune pattern score. Kaplan-Meier and Cox analyses indicated this pattern as an independent risk factor for UC. We observed significant associations between the immune pattern, tumor progression, and immune cell infiltration. Differential expression analysis showed correlations with m6A regulators expression. This immune pattern proved effective in predicting immunotherapy response in UC in real-world settings.

CONCLUSION

The study identified a m6A-modified immune pattern in UC, offering prognostic and therapeutic response predictions. This emphasizes that immune genes may influence tumor immune status and progression through m6A modifications.

Hypoxia-induced ALKBH5 aggravates synovial aggression and inflammation in rheumatoid arthritis by regulating the m6A modification of CH25H

Previous studies have shown that epigenetic factors are involved in the occurrence and development of rheumatoid arthritis (RA). However, the role of N6-methyladenosine (m6A) methylation in RA has not been determined. The aim of this study was to investigate the role and regulatory mechanisms of hypoxia-induced expression of the m6A demethylase alkB homolog 5 (ALKBH5) in RA fibroblast-like synoviocytes (FLSs). Synovial tissues were collected from RA and osteoarthritis (OA) patients, and RA FLSs were obtained. ALKBH5 expression in RA FLSs and collagen-induced arthritis (CIA) model rats was determined using quantitative reverse transcription-PCR (qRT-PCR), western blotting and immunohistochemistry (IHC). Using ALKBH5 overexpression and knockdown, we determined the role of ALKBH5 in RA FLS aggression and inflammation. The role of ALKBH5 in RA FLS regulation was explored using m6A-methylated RNA sequencing and methylated RNA immunoprecipitation coupled with quantitative real-time PCR. The expression of ALKBH5 was increased in RA synovial tissues, CIA model rats and RA FLSs, and a hypoxic environment increased the expression of ALKBH5 in FLSs. Increased expression of ALKBH5 promoted the proliferation and migration of RA-FLSs and inflammation. Conversely, decreased ALKBH5 expression inhibited the migration of RA-FLSs and inflammation. Mechanistically, hypoxia-induced ALKBH5 expression promoted FLS aggression and inflammation by regulating CH25H mRNA stability. Our study elucidated the functional roles of ALKBH5 and mRNA m6A methylation in RA and revealed that the HIF1α/2α-ALKBH5-CH25H pathway may be key for FLS aggression and inflammation. This study provides a novel approach for the treatment of RA by targeting the HIF1α/2α-ALKBH5-CH25H pathway.

Emerging function of main RNA methylation modifications in the immune microenvironment of digestive system tumors

Digestive system tumors have been reported in more than 25% of all cancer cases worldwide, bringing a huge burden on the healthcare system. RNA methylation modification-an important post-transcriptional modification-has become an active research area in gene regulation. It is a dynamic and reversible process involving several enzymes, such as methyltransferases, demethylases, and methylation reader proteins. This review provides insights into the role of three major methylation modifications, namely m6A, m5C, and m1A, in the development of digestive system tumors, specifically in the development of tumor immune microenvironment (TIME) of these malignancies. Abnormal methylation modification affects immunosuppression and antitumor immune response by regulating the recruitment of immune cells and the release of immune factors. Understanding the mechanisms by which RNA methylation regulates digestive system tumors will be helpful in exploring new therapeutic targets.

M6A RNA methylation in biliary tract cancer: the function roles and potential therapeutic implications

Biliary tract cancers (BTCs) are relatively rare malignancies with a poor prognosis. For advanced BTCs, the efficacy of current chemotherapeutic approaches is limited. Consequently, there is an urgent need to deepen our understanding of the molecular mechanisms underlying BTC tumorigenesis and development for the exploration of effective targeted therapies. N6-methyladenosine (m6A), the most abundant RNA modifications in eukaryotes, is found usually dysregulated and involved in tumorigenesis, progression, and drug resistance in tumors. Numerous studies have confirmed that aberrant m6A regulators function as either oncogenes or tumor suppressors in BTCs by the reversible regulation of RNA metabolism, including splicing, export, degradation and translation. In this review, we summarized the current roles of the m6A regulators and their functional impacts on RNA fate in BTCs. The improved understanding of m6A modification in BTCs also provides a reasonable outlook for the exploration of new diagnostic strategies and efficient therapeutic targets.

Significance of N6-methyladenosine RNA methylation regulators in diagnosis and subtype classification of primary Sjögren's syndrome

The importance of N6-methyladenine (m6A) in mRNA metabolism, physiology, pathology and other life processes is well recognized. However, the exact role of m6A regulators in primary Sjögren's syndrome (PSS) remains unclear. In this study, we used bioinformatics and machine learning random forest approach to screen eight key m6A regulators from the Gene Expression Omnibus GSE7451, GSE40611 and GSE84844 datasets. An accurate nomogram model for predicting PSS risk was established based on these regulators. And using consensus clustering, patients diagnosed with PSS were classified into two different m6A patterns. We found that patients in group B had higher m6A scores compared to those in group A: furthermore, both groups were closely related to immunity and possibly to other diseases. These results emphasise the important role of m6A regulators in the pathogenesis of PSS. Our study of m6A patterns may inform future immunotherapy strategies for PSS.

Exploring the prognostic potential of m6A methylation regulators in low-grade glioma: implications for tumor microenvironment modulation

BACKGROUND

The biological behavior of low-grade glioma (LGG) is significantly affected by N6-methyladenosine (m6A) methylation, an essential epigenetic alteration. Therefore, it is crucial to create a prognostic model for LGG by utilizing genes that regulate m6A methylation.

METHODS

Using TCGA and GTEx databases. We examined m6A modulator levels in LGG and normal tissues, and investigated PD-L1 and PD-1 expression, immune scores, immune cell infiltration, tumor immune microenvironment (TIME) and potential underlying mechanisms in different LGG clusters. We also performed immunohistochemistry and RT-qPCR to identify essential m6A adjustment factor.

RESULTS

The results showed that m6A regulatory element expression was significantly increased in LGG tissues and was significantly associated with TMIE. A substantial increase in PD-L1 and PD-1 levels in LGG tissues and high-risk cohorts was observed. PD-L1 expression was positively correlated with FTO, ZCCHC4, and HNRNPD, whereas PD-1 expression was negatively correlated with FTO, ZC3H7B, and HNRNPD. The prognostic signature created using regulators of m6A RNA methylation was shown to be strongly associated with the overall survival of LGG patients, and FTO and ZCCHC4 were confirmed as independent prognostic markers by clinical samples. Furthermore, the results revealed different TIME characteristics between the two groups of patients, indicating disrupted signaling pathways associated with LGG.

CONCLUSION

Our results present that the m6A regulators play vital role in regulating PD-L1/PD-1 expression and the infiltration of immune cells, thereby exerting a sizable impact on the TIME of LGG. Therefore, m6A regulators have precise predictive value in the prognosis of LGG.

N6-Methyladenosine (m6A) Modification in Natural Immune Cell-Mediated Inflammatory Diseases

The post-transcriptional N6-methyladenosine (m6A) modification of RNA influences stability, transport, and translation with implications for various physiological and pathological processes. Immune cell development, differentiation, and activation are also thought to be regulated by m6A and affect host defense against pathogens and inflammatory response with impacts on infectious, neoplastic, autoimmune, cardiovascular, hepatic, and osteal diseases. The current review summarizes recent research on m6A in monocyte/macrophages, neutrophils, dendritic cells, natural killer cells, and microglia and gives insights into epigenetic modifications of the immune system and novel therapeutic strategies for immune-related diseases.

CYFIP2 serves as a prognostic biomarker and correlates with tumor immune microenvironment in human cancers

BACKGROUND

The mechanisms whereby CYFIP2 acts in tumor development and drives immune infiltration have been poorly explored. Thus, this study aimed to identifying the role of CYFIP2 in tumors and immune response.

METHODS

In this study, we first explored expression patterns, diagnostic role and prognostic value of CYFIP2 in cancers, particularly in lung adenocarcinoma (LUAD). Then, we performed functional enrichment, genetic alterations, DNA methylation analysis, and immune cell infiltration analysis of CYFIP2 to uncover its potential mechanisms involved in immune microenvironment.

RESULTS

We found that CYFIP2 significantly differentially expressed in different tumors including LUAD compared with normal tissues. Furthermore, CYFIP2 was found to be significantly correlated with clinical parameters in LUAD. According to the diagnostic and survival analysis, CYFIP2 may be employed as a potential diagnostic and prognostic biomarker. Moreover, genetic alterations revealed that mutation of CYFIP2 was the main types of alterations in different cancers. DNA methylation analysis indicated that CYFIP2 mRNA expression correlated with hypomethylation. Afterwards, functional enrichment analysis uncovered that CYFIP2 was involved in tumor-associated and immune-related pathways. Immune infiltration analysis indicated that CYFIP2 was significantly correlated with immune cells infiltration. In particular, CYFIP2 was strongly linked with immune microenvironment scores. Additionally, CYFIP2 exhibited a significant relationship with immune regulators and immune-related genes including chemokines, chemokines receptors, and MHC genes.

CONCLUSION

Our results suggested that CYFIP2 may serve as a prognostic cancer biomarker for determining prognosis and might be a promising therapeutic strategy for tumor immunotherapy.

METTL3 Regulates the m6A Modification of NEK7 to Inhibit the Formation of Osteoarthritis

OBJECTIVE

Osteoarthritis (OA) is a common degenerative joint disease. The occurrence of OA slowly destroys the soft tissue structure of the patient's joint. Severe cases could lead to disability. Current studies had shown that inhibition of chondrocytes pyroptosis could slow down the progression of OA. Our work aimed to explore the specific mechanisms and ways of regulating this process.

DESIGN

In this work, the level of N6-methyladenosine (m6A) in clinical tissues was detected by ribonucleic acid (RNA) m6A dot blot. qRT-PCR (quantitative real-time polymerase chain reaction) was used to detect the messenger RNA (mRNA) expression level of m6A modified enzyme in clinical tissues. MTT (3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromid) and flow cytometry were used to detect the effect of sh-METTL3 (methyltransferase like 3) and NIMA-related kinase 7 (NEK7) transfection on chondrocytes pyroptosis in OA. Western blot was used to detect the protein expression levels of pyroptosis-related proteins. ELISA (enzyme-linked immunosorbent assay) was used to measure the protein concentration of inflammatory cytokines. The SRAMP online database was used to predict the m6A site of NEK7. HE staining was used to assess the progression of OA in mice.

RESULTS

The level of m6A in clinical samples of OA patients was higher, and METTL3 was significantly higher expressed in clinical samples of OA patients. We provided evidence that low expression of METTL3 inhibited chondrocytes pyroptosis. In addition, Rescue experiments and in vivo experiments had shown that METTL3 in combination with NEK7 inhibited the progression of OA by promoting chondrocytes pyroptosis.

CONCLUSIONS

METTL3 regulates m6A modification of NEK7 and inhibits OA progression.

METTL14 regulates microglia/macrophage polarization and NLRP3 inflammasome activation after ischemic stroke by the KAT3B-STING axis

N6-methyladenosine (m6A) plays a crucial role in ischemic stroke, whereas the role of methyltransferase-like 14 (METTL14) in ischemic stroke remains unknown. A model of middle cerebral artery occlusion (MCAO) in rats and oxygen-glucose deprivation/reperfusion (OGD/R) model in HAPI cells were used to simulate ischemic stroke in vivo and in vitro. We found that METTL14 level was upregulated in microglia/macrophage after MCAO and OGD/R. METTL14 enhanced the expression of KAT3B by promoting the m6A modification of KAT3B mRNA. STING has been identified as a target for KAT3B and KAT3B increased STING expression by enhancing H3K27ac in the STING promoter. METTL14 promoted M1 polarization and NLRP3 inflammasome/pyroptosis axis by the KAT3B-STING signaling after OGD/R. METTL14 depletion relieved brain injury by inhibiting M1-like microglia/macrophage polarization and NLRP3 inflammasome/pyroptosis axis in MCAO rats. These findings indicate that METTL14 depletion relieves MCAO-induced brain injury, probably via switching microglia/macrophage from M1 towards M2 and restraining NLRP3 inflammasome/pyroptosis axis in microglia/macrophage.

System analysis identifies UBE2C as a novel oncogene target for adrenocortical carcinoma

Ubiquitin Conjugating Enzyme 2C (UBE2C) is an emerging target gene for tumor progression. However, the tumorigenic effect and mechanism of UBE2C in adrenocortical carcinoma (ACC) remains unclear. Systematic investigation of the tumorigenic effect of UBE2C may help in understanding its prognostic value in adrenocortical carcinoma. First, we exploited the intersection on DFS-related genes, OS-related genes, highly expressed genes in adrenocortical carcinoma as well as differentially expressed genes (DEGs) between tumor and normal, and then obtained 20 candidate genes. UBE2C was identified to be the most significant DEG between tumor and normal. It is confirmed that high expression of UBE2C was strongly associated with poor prognosis in patients with ACC by analyzing RNA-seq data of ACC obtained from the Cancer Genome Atlas (TCGA) database implemented by ACLBI Web-based Tools. UBE2C expression could also promote m6A modification and stemness in ACC. We found that UBE2C expression is positively associated with the expression of CDC20, CDK1, and CCNA2 using ACLBI Web-based Tools, indicated the hyperactive cell cycle progression present in ACC with high UBE2C expression. In addition, UBE2C knockdown could significantly inhibit the proliferation, migration, invasion, EMT of adrenocortical carcinoma cells as well as the cell cycle progression in vitro. Notably, pan-cancer analysis also identified UBE2C as an oncogene in various tumors. Taken together, UBE2C was strongly associated with poor prognosis of patients with ACC by promoting cell cycle progression and EMT. This study provides a new theoretical basis for the development of UBE2C as a molecular target for the treatment of ACC.

N6-methyladenosine (m6A) in cancer stem cell: From molecular mechanisms to therapeutic implications

The emergence of drug resistance and metastasis has long been a difficult problem for cancer treatment. Recent studies have shown that cancer stem cell populations are key factors in the regulation of cancer aggressiveness, relapse and drug resistance. Cancer stem cell (CSC) populations are highly plastic and self-renewing, giving them unique metabolic, metastatic, and chemotherapy resistance properties. N6-methyladenosine (m6A) is the most abundant internal modification of mRNA and is involved in a variety of cell growth and development processes, including RNA transcription, alternative splicing, degradation, and translation. It has also been linked to the development of various cancers. At present, the important role of m6A in tumour progression is gradually attracting attention, especially in the tumour stemness regulation process. Abnormal m6A modifications regulate tumour metastasis, recurrence and drug resistance. This paper aims to explore the regulatory mechanism of m6A in CSCs and clinical therapy, clarify its regulatory network, and provide theoretical guidance for the development of clinical targets and improvement of therapeutic effects.