RNA 5-Methylcytosine Regulator NSUN3 promotes tumor progression through regulating immune infiltration in head and neck squamous cell carcinoma

Insights into the role of the N6-methyladenosine reader IGF2BP3 in the progression of oral squamous cell carcinoma and its connection to cell-cycle control

The genome of oral squamous cell carcinoma (OSCC) has been extensively characterized via bulk sequencing, revealing a multitude of genetic changes. The gene IGF2BP3, which encodes for the insulin-like growth factor 2 mRNA-binding protein 3, has been observed to be highly expressed in several types of cancer. This finding suggests that IGF2BP3 may play a significant role in the initiation and advancement of cancer. Nevertheless, the mechanisms by which IGF2BP3 contribute to OSCC are yet to be fully understood. In this study, we have observed that IGF2BP3 exhibits overexpression in OSCC. Based on our findings from bulk sequencing analysis, we have concluded that IGF2BP3 could potentially serve as a biomarker for predicting poor prognosis in OSCC. Moreover, it has been demonstrated that IGF2BP3 exhibits a significant association with the initiation and advancement of tumors both in vivo and in vitro. The evaluation of IGF2BP3 expression levels in relation to the cell cycle stage was conducted using single-cell RNA sequencing data. Tumor cells characterized by elevated IGF2BP3 expression demonstrated a higher percentage of cells in the G2/M transition phase. This study presents new findings indicating that the molecular target IGF2BP3 can serve as a prognostic indicator for tumors and has an impact on the development and progression of OSCC by influencing the regulation of the cell cycle.

RNA m5C methylation: a potential modulator of innate immune pathways in hepatocellular carcinoma

RNA 5-methylcytosine (m5C) methylation plays a crucial role in hepatocellular carcinoma (HCC). As reported, aberrant m5C methylation is closely associated with the progression, therapeutic efficacy, and prognosis of HCC. The innate immune system functions as the primary defense mechanism in the body against pathogenic infections and tumors since it can activate innate immune pathways through pattern recognition receptors to exert anti-infection and anti-tumor effects. Recently, m5C methylation has been demonstrated to affect the activation of innate immune pathways including TLR, cGAS-STING, and RIG-I pathways by modulating RNA function, unveiling new mechanisms underlying the regulation of innate immune responses by tumor cells. However, research on m5C methylation and its interplay with innate immune pathways is still in its infancy. Therefore, this review details the biological significance of RNA m5C methylation in HCC and discusses its potential regulatory relationship with TLR, cGAS-STING, and RIG-I pathways, thereby providing fresh insights into the role of RNA methylation in the innate immune mechanisms and treatment of HCC.

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.

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.