RNA methyltransferase NSUN2 promotes hypopharyngeal squamous cell carcinoma proliferation and migration by enhancing TEAD1 expression in an m5C-dependent manner

NSUN2-mediated RNA methylation: Molecular mechanisms and clinical relevance in cancer

Cancer remains a leading cause of morbidity and mortality worldwide, necessitating the ongoing investigation of molecular targets for improved diagnosis, prognosis, and therapy. Among these targets, RNA modifications, particularly N5-methylcytosine (m5C) in RNA, have emerged as critical regulators of gene expression and cellular functions. NOP2/Sun RNA methyltransferase family member 2 (NSUN2) is a key enzyme in m5C modification, significantly influencing various biological processes and tumorigenesis. NSUN2 methylates multiple RNA species, including transfer RNAs (tRNAs), messenger RNAs (mRNAs), and non-coding RNAs, impacting RNA stability, translation efficiency, and cellular stress responses. These modifications, in turn, affect cell proliferation, differentiation, and survival. In cancer, NSUN2 is frequently upregulated, associated with aggressive tumor phenotypes, poor prognosis, and therapy resistance. Its role in oncogenic signaling pathways further underscores its importance in cancer biology. This review offers a comprehensive overview of NSUN2's role in cancer, focusing on its involvement in RNA methylation and its implications for tumor initiation and progression. Additionally, we explore the potential of NSUN2 as a biomarker for cancer diagnosis and prognosis, and its promise as a therapeutic target.

ETV4/NSUN2 Axis modulates aerobic glycolysis and malignancy in HSCC

This study delves into the molecular intricacies of hypopharyngeal squamous cell carcinoma (HSCC), specifically focusing on the pivotal role played by ETS translocation variant 4 (ETV4) in aerobic glycolysis. The objective is to uncover new targets for early diagnosis and treatment of HSCC. ETV4 expression in HSCC tissues was rigorously examined, revealing its association with patient survival. Through comprehensive experimentation, we demonstrated that ETV4 activation promotes HSCC cell proliferation and invasion while inhibiting apoptosis. Furthermore, in vivo experiments confirmed the tumor-promoting effect of ETV4 activation. The study elucidated the binding of ETV4 to the NSUN2 promoter and its influence on PKM2 expression, thereby regulating glycolysis and cellular functions in HSCC.

Biological function molecular pathways and druggability of DNMT2/TRDMT1

5-methylcytosine (m5C) is among the most common epigenetic modification in DNA and RNA molecules, and plays an important role in the animal development and disease pathogenesis. Interestingly, unlike other m5C DNA methyltransferases (DNMTs), DNMT2/TRDMT1 has the double-substrate specificity and adopts a DNMT-similar catalytic mechanism to methylate RNA. Moreover, it is widely involved in a variety of physiological regulatory processes, such as the gene expression, precise protein synthesis, immune response, and disease occurrence. Thus, comprehending the epigenetic mechanism and function of DNMT2/TRDMT1 will probably provide new strategies to treat some refractory diseases. Here, we discuss recent studies on the spatiotemporal expression pattern and post-translational modifications of DNMT2/TRDMT1, and summarize the research advances in substrate characteristics, catalytic recognition mechanism, DNMT2/TRDMT1-related genes or proteins, pharmacological application, and inhibitor development. This review will shed light on the pharmacological design by targeting DNMT2/TRDMT1 to treat parasitic, viral and oncologic diseases.

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.

NSUN2 affects diabetic retinopathy progression by regulating MUC1 expression through RNA m5C methylation

BACKGROUND

Diabetic retinopathy (DR) is the leading cause of blinding eye disease among working adults and is primarily attributed to the excessive proliferation of microvessels, which leads to vitreous hemorrhage and retinal traction, thereby significantly impairing patient vision. NSUN2-mediated RNA m5C methylation is implicated in various diseases, and in this investigation, we focused on elucidating the impact of NSUN2 on the regulation of the expression of the downstream gene MUC1, specifically through RNA m5C methylation, on the progression of DR.

METHOD

Utilizing Microarray analysis, we examined patient vitreous fluid to pinpoint potential therapeutic targets for DR. Differential expression of NSUN2 was validated through qRT-PCR, Western blot, and immunofluorescence in human tissue, animal tissue, and cell model of DR. The relationship between NSUN2 and DR was explored in vitro and in vivo through gene knockdown and overexpression. Various techniques, such as MeRIP-qPCR and dot blot, were applied to reveal the downstream targets and mechanism of action of NSUN2.

RESULTS

The levels of both NSUN2 and RNA m5C methylation were significantly elevated in the DR model. Knockdown of NSUN2 mitigated DR lesion formation both in vitro and in vivo. Mechanistically, NSUN2 promoted MUC1 expression by binding to the RNA m5C reader ALYREF. Knockdown of ALYREF resulted in DR lesion alterations similar to those observed with NSUN2 knockdown. Moreover, MUC1 overexpression successfully reversed a series of DR alterations induced by NSUN2 silencing.

CONCLUSIONS

NSUN2 regulates the expression of MUC1 through ALYREF-mediated RNA m5C methylation, thereby regulating the progression of DR and providing a new option for the treatment of DR in the future.

RNA methylation-related inhibitors: Biological basis and therapeutic potential for cancer therapy

RNA methylation is widespread in nature. Abnormal expression of proteins associated with RNA methylation is strongly associated with a number of human diseases including cancer. Increasing evidence suggests that targeting RNA methylation holds promise for cancer treatment. This review specifically describes several common RNA modifications, such as the relatively well-studied N6-methyladenosine, as well as 5-methylcytosine and pseudouridine (Ψ). The regulatory factors involved in these modifications and their roles in RNA are also comprehensively discussed. We summarise the diverse regulatory functions of these modifications across different types of RNAs. Furthermore, we elucidate the structural characteristics of these modifications along with the development of specific inhibitors targeting them. Additionally, recent advancements in small molecule inhibitors targeting RNA modifications are presented to underscore their immense potential and clinical significance in enhancing therapeutic efficacy against cancer. KEY POINTS: In this paper, several important types of RNA modifications and their related regulatory factors are systematically summarised. Several regulatory factors related to RNA modification types were associated with cancer progression, and their relationships with cancer cell migration, invasion, drug resistance and immune environment were summarised. In this paper, the inhibitors targeting different regulators that have been proposed in recent studies are summarised in detail, which is of great significance for the development of RNA modification regulators and cancer treatment in the future.

RNA modifications in cancer

Currently, more than 170 modifications have been identified on RNA. Among these RNA modifications, various methylations account for two-thirds of total cases and exist on almost all RNAs. Roles of RNA modifications in cancer are garnering increasing interest. The research on m6A RNA methylation in cancer is in full swing at present. However, there are still many other popular RNA modifications involved in the regulation of gene expression post-transcriptionally besides m6A RNA methylation. In this review, we focus on several important RNA modifications including m1A, m5C, m7G, 2'-O-Me, Ψ and A-to-I editing in cancer, which will provide a new perspective on tumourigenesis by peeking into the complex regulatory network of epigenetic RNA modifications, transcript processing, and protein translation.

NSUN2-mediated mRNA m5C Modification Regulates the Progression of Hepatocellular Carcinoma

RNA modifications affect many biological processes and physiological diseases. The 5-methylcytosine (m5C) modification regulates the progression of multiple tumors. However, its characteristics and functions in hepatocellular carcinoma (HCC) remain largely unknown. Here, we found that HCC tissues had a higher m5C methylation level than the adjacent normal tissues. Transcriptome analysis revealed that the hypermethylated genes mainly participated in the phosphokinase signaling pathways, such as the Ras and PI3K-Akt pathways. The m5C methyltransferase NSUN2 was highly expressed in HCC tissues. Interestingly, the expression of many genes was positively correlated with the expression of NSUN2, including GRB2, RNF115, AATF, ADAM15, RTN3, and HDGF. Real-time PCR assays further revealed that the expression of the mRNAs of GRB2, RNF115, and AATF decreased significantly with the down-regulation of NSUN2 expression in HCC cells. Furthermore, NSUN2 could regulate the cellular sensitivity of HCC cells to sorafenib via modulating the Ras signaling pathway. Moreover, knocking down NSUN2 caused cell cycle arrest. Taken together, our study demonstrates the vital role of NSUN2 in the progression of HCC.

5-Methylcytosine-related lncRNAs: predicting prognosis and identifying hot and cold tumor subtypes in head and neck squamous cell carcinoma

BACKGROUND

5-Methylcytosine (m⁵C) methylation is recognized as an mRNA modification that participates in biological progression by regulating related lncRNAs. In this research, we explored the relationship between m⁵C-related lncRNAs (mrlncRNAs) and head and neck squamous cell carcinoma (HNSCC) to establish a predictive model.

METHODS

RNA sequencing and related information were obtained from the TCGA database, and patients were divided into two sets to establish and verify the risk model while identifying prognostic mrlncRNAs. Areas under the ROC curves were assessed to evaluate the predictive effectiveness, and a predictive nomogram was constructed for further prediction. Subsequently, the tumor mutation burden (TMB), stemness, functional enrichment analysis, tumor microenvironment, and immunotherapeutic and chemotherapeutic responses were also assessed based on this novel risk model. Moreover, patients were regrouped into subtypes according to the expression of model mrlncRNAs.

RESULTS

Assessed by the predictive risk model, patients were distinguished into the low-MLRS and high-MLRS groups, showing satisfactory predictive effects with AUCs of 0.673, 0.712, and 0.681 for the ROCs, respectively. Patients in the low-MLRS groups exhibited better survival status, lower mutated frequency, and lower stemness but were more sensitive to immunotherapeutic response, whereas the high-MLRS group appeared to have higher sensitivity to chemotherapy. Subsequently, patients were regrouped into two clusters: cluster 1 displayed immunosuppressive status, but cluster 2 behaved as a hot tumor with a better immunotherapeutic response.

CONCLUSIONS

Referring to the above results, we established a m⁵C-related lncRNA model to evaluate the prognosis, TME, TMB, and clinical treatments for HNSCC patients. This novel assessment system is able to precisely predict the patients' prognosis and identify hot and cold tumor subtypes clearly for HNSCC patients, providing ideas for clinical treatment.

Vital roles of m5C RNA modification in cancer and immune cell biology

RNA modification plays an important role in epigenetics at the posttranscriptional level, and 5-methylcytosine (m5C) has attracted increasing attention in recent years due to the improvement in RNA m5C site detection methods. By influencing transcription, transportation and translation, m5C modification of mRNA, tRNA, rRNA, lncRNA and other RNAs has been proven to affect gene expression and metabolism and is associated with a wide range of diseases, including malignant cancers. RNA m5C modifications also substantially impact the tumor microenvironment (TME) by targeting different groups of immune cells, including B cells, T cells, macrophages, granulocytes, NK cells, dendritic cells and mast cells. Alterations in immune cell expression, infiltration and activation are highly linked to tumor malignancy and patient prognosis. This review provides a novel and holistic examination of m5C-mediated cancer development by examining the exact mechanisms underlying the oncogenicity of m5C RNA modification and summarizing the biological effects of m5C RNA modification on tumor cells as well as immune cells. Understanding methylation-related tumorigenesis can provide useful insights for the diagnosis as well as the treatment of cancer.

NAT10-mediated AXL mRNA N4-acetylcytidine modification promotes pancreatic carcinoma progression

Although the patient's survival time in various cancers has significantly increased in recent decades, the overall 5-year survival rate of pancreatic ductal adenocarcinoma (PDAC) has remained virtually unchanged due to rapid progression and metastasis. While N-acetyltransferase 10 (NAT10) has been identified as a regulator of mRNA acetylation in many malignancies, its role in PDAC remains unclear. Here, we found that NAT10 mRNA and protein levels were upregulated in PDAC tissues. Increased NAT10 protein expression was significantly correlated with poor prognosis in PDAC patients. Through our experiments, we demonstrated that NAT10 acted as an oncogene to promote PDAC tumorigenesis and metastasis in vitro and in vivo. Mechanistically, NAT10 exerts its oncogenic effects by promoting mRNA stability of receptor tyrosine kinase AXL in an ac4C-dependent manner leading to increased AXL expression and further promoting PDAC cell proliferation and metastasis. Together, our findings highlight the critical of NAT10 in PDAC progression and reveal a novel epigenetic mechanism by which modified mRNA acetylation promotes PDAC metastasis.

CSMD1 suppresses cancer progression by inhibiting proliferation, epithelial-mesenchymal transition, chemotherapy-resistance and inducing immunosuppression in esophageal squamous cell carcinoma

Human CUB and Sushi multiple domains (CSMD1) is considered a crucial role in cancer progression, but the specific function in esophageal squamous cell carcinoma (ESCC) is not clear. Understanding the role of CSMD1 in ESCC progression may lead to a novel strategy for ESCC treatment. Here, we found that both CSMD1 mRNA and protein levels were downregulated in ESCC tissues. Reduced CSMD1 expression was correlated with a poor prognosis in ESCC patients. CSMD1 expression inhibited proliferation, migration and invasion in ESCC cell lines in vitro. CSMD1 deficiency in established xenografted tumors increases tumor size and weight. We further found that CSMD1-overexpression cells are more sensitive to chemotherapy. Moreover, we addressed the role of CSMD1 in the CD8⁺ T cell immune response. An in vitro killing assay showed that the cytotoxicity of CD8⁺ T cells was inhibited in CSMD1-overexpression tumor cells. In vivo, in CSMD1 deficiency tumor-bearing mice activation and expansion of CD8⁺ T cells were increased. Further investigation showed that CSMD1 expression on tumor cells was positively correlated with CD8⁺ T cells infiltration and cytokines secretion. These findings highlight that CSMD1 is a tumor suppressor gene in ESCC patients and a positive regulator of CD8⁺ T cells expansion and activation, and could increase cytokines secretion, indicating that tumor cell-associated CSMD1 might be a target for ESCC.

5-methylcytosine RNA methyltransferases and their potential roles in cancer

In recent years, 5-methylcytosine (m⁵C) RNA modification has emerged as a key player in regulating RNA metabolism and function through coding as well as non-coding RNAs. Accumulating evidence has shown that m⁵C modulates the stability, translation, transcription, nuclear export, and cleavage of RNAs to mediate cell proliferation, differentiation, apoptosis, stress responses, and other biological functions. In humans, m⁵C RNA modification is catalyzed by the NOL1/NOP2/sun (NSUN) family and DNA methyltransferase 2 (DNMT2). These RNA modifiers regulate the expression of multiple oncogenes such as fizzy-related-1, forkhead box protein C2, Grb associated-binding protein 2, and TEA domain transcription factor 1, facilitating the pathogenesis and progression of cancers. Furthermore, the aberrant expression of methyltransferases have been identified in various cancers and used to predict the prognosis of patients. In this review, we present a comprehensive overview of m⁵C RNA methyltransferases. We specifically highlight the potential mechanism of action of m⁵C in cancer. Finally, we discuss the prospect of m⁵C-relative studies.

NSUN2 Promotes Tumor Progression and Regulates Immune Infiltration in Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is one of the most common malignancies in the head and neck with a complex etiology, such as environmental factors, genetic factors, and Epstein-Barr virus infection. The NOP2/Sun domain family, member 2 (NSUN2) is a methyltransferase of m5C methylation modification that has been reported to be involved in the occurrence and progression of various tumors, but its role in NPC remains unclear. In this study, we found that NSUN2 was upregulated in NPC and predicted a poor prognosis for NPC patients in both GEO datasets and our tissue microarrays containing 125 NPC tissues. Next, we demonstrated that NSUN2 promoted the proliferation, migration, and invasion of NPC cells in vitro. Additionally, the differential expression genes between NSUN2-high and low expression patients were mainly enriched in multi-immune cell activation and proliferation. Furthermore, NSUN2 negatively regulates immune cell infiltration in the tumor microenvironment (TME) of NPC, which indicates that the NSUN2 level may be negatively correlated with the sensitivity of immunotherapy and chemotherapy. In conclusion, our findings highlight that NSUN2 might act as an important oncogene involved in NPC progression and serve as a potential biomarker to predict poor prognosis and drug sensitivity of NPC patients.

The RNA N6-Methyladenosine Demethylase FTO Promotes Head and Neck Squamous Cell Carcinoma Proliferation and Migration by Increasing CTNNB1

Objective

In this study, we aimed to investigate the role of RNA N6-methyladenosine demethylase fat mass and obesity-associated protein (FTO) in head and neck squamous cell carcinoma (HNSCC).

Methods

Clinical data downloaded from The Cancer Genome Atlas (TCGA) database were used to analyze the relationship between mRNA levels of FTO, METTL3, METTL14, and ALKBH5, and the overall survival in cancer and para-cancer datasets. FTO expression in tumor and normal tissues was compared using immunohistochemistry, and its relationship with overall survival was analyzed based on the Kaplan–Meier method. The FaDu cell line with high FTO levels was chosen from five HNSCC cell lines for further experiments. FTO was verified as an oncogene in HNSCC by in vitro loss-of-function and overexpression studies, cell proliferation assay, wound healing assay, and identification of expression changes of epithelial–mesenchymal transition (EMT)-related markers. Catenin beta 1 (CTNNB1) was confirmed as a downstream target gene of FTO with additional methods like the GEPIA online tool, qRT-PCR, Western blotting, and dot blot assay.

Results

We found that FTO expression was significantly upregulated in HNSCC datasets and tissues. Increased FTO expression indicated a trend towards poor prognosis and was found to promote disease proliferation and migration. Mechanistically, cell proliferation assay, wound healing assay, and identification of expression changes of EMT-related markers demonstrated that FTO could act as an oncogene in HNSCC. FTO expression was significantly correlated with CTNNB1 expression. Moreover, it exerted a tumorigenic effect by increasing CTNNB1 expression in an m⁶A-dependent manner.

Conclusion

FTO promotes head and neck squamous cell carcinoma proliferation and migration by increasing CTNNB1 in an m⁶A-dependent manner.

Small Intestinal Submucosa Membrane Modified by Fusion Peptide-Mediated Extracellular Vesicles to Promote Tissue Regeneration

Tissue injury, which often occurs in daily life, remains challenging in clinical medicine. Developing a novel biomaterial with the capability to provide an ideal microenvironment and homeostasis around the wound is highly desirable for effective tissue regenerative medicine. The small intestinal submucosa (SIS) membrane possesses a precise spatial structure with excellent biocompatibility. Extracellular vesicles (EVs) derived from umbilical cord mesenchymal stem cells can achieve rapid cell proliferation and migration with little immune response by creating a satisfactory microenvironment. In this study, fusion peptide-mediated EVs are able to modify the surface of the SIS membrane via specific combination. In vitro studies prove that modified SIS membranes can promote cell migration and spreading. This phenomenon may be because of the activation of TEADs, which regulate cell behavior. By constructing a rat abdominal wall defect model, it is further demonstrated that the modified SIS membrane is more conducive to tissue regeneration. Collectively, these results suggest that SIS membranes modified by fusion peptide-mediated EVs achieve excellent biofunction and provide promising prospects for tissue regeneration.