No abstract

The chemical modification of RNA is a newly discovered epigenetic regulation mechanism in cells and plays a crucial role in a variety of biological processes. N6-methyladenine (m6A) mRNA modification is the most abundant form of posttranscriptional RNA modification in eukaryotes. Through the development of m6A RNA sequencing, the relevant molecular mechanism of m6A modification has gradually been revealed. It has been found that the effect of m6A modification on RNA metabolism involves processing, nuclear export, translation and even decay. As the most common malignant tumour of the central nervous system, gliomas (especially glioblastoma) have a very poor prognosis, and treatment efficacy is not ideal even with the application of high-intensity treatment measures of surgery combined with chemoradiotherapy. Exploring the origin and development mechanisms of tumour cells from the perspective of tumour biogenesis has always been a hotspot in the field of glioma research. Emerging evidence suggests that m6A modification can play a key role in gliomas through a variety of mechanisms, providing more possibilities for early diagnosis and targeted therapy of gliomas. The aim of the present review is to focus on the research progress regarding the association between m6A modification and gliomas. And to provide a theoretical basis according to the currently available literature for further exploring this association. This review may provide new insights for the molecular mechanism, early diagnosis, histologic grading, targeted therapy and prognostic evaluation of gliomas.

Aim: This review aims to systematically describe the biogenesis and degradation of circular RNAs (circRNAs), discusses the major functions of circRNAs, introduces the mechanisms by which circRNAs play a role in cancer, comprehensively summarize the relationship between circRNAs and anticarcinogen resistance as well as underlying specific mechanisms in multiple cancers. Materials & methods: We screened and analyzed large quantity of scientific papers which associated with circRNAs, noncoding RNAs, function, cancer, drug resistance and chemoresistance, and then summarized in Figures 1 & 2 & Table 1. Results & conclusion: The biogenesis, degradation and function of circRNAs are specially compared with other noncoding RNAs, it can affect cancer pathogenesis and progression and are implicated in mediating resistance to various anticarcinogens in various types of cancer.

Exosomes are nanoscale phospholipid bilayer vesicles that can be artificially engineered into vectors for the treatment of cancer. Circular RNA (circRNA), a type of non-coding RNA, has crucial regulatory functions in various aspects of cancer, such as tumorigenesis, apoptosis, proliferation, invasion, metastasis and chemo-and radiotherapeutic resistance, as well as in cancer prognosis. Notably, the exosomal transfer of circRNAs may function to both promote and inhibit cancer. Numerous studies have addressed the importance of circRNAs in cancer and non-coding RNAs (such as microRNAs and long non-coding RNAs) in exosomes. However, little research has focussed on a class of RNAs called exosomal circRNAs. The present review discusses current studies regarding exosomal circRNAs, including their biogenesis and biological functions, their abundance in exosomes and possible sorting mechanisms and their potential roles in both promoting and inhibiting cancer. It is predicted that in the next five years there will be increasing research exploring the functional mechanisms of exosomal circRNA in various diseases, in particular their roles in cancer genesis and progression.

Gastric cancer (GC) is one of the most common malignancies worldwide manifesting high morbidity and mortality. Cancer-associated fibroblasts (CAFs), important components of the tumor microenvironment, are essential for tumorigenesis and progression. Exosomes secreted from CAFs have been reported as the critical molecule-vehicle in intercellular crosstalk. However, the precise mechanism underlying the effect of CAFs remains to be fully investigated. In this study, we aimed to determine the role of CAFs and their exosomes in the progression of GC and related mechanisms. The results revealed that miRNA-34 was downregulated in both GC fibroblasts (GCFs) and GC cell lines while the overexpression of miRNA-34 suppressed the proliferation, invasion, and motility of GC cell lines. Coculturing GC cells with miRNA-34-overexpressing GCFs led to the suppression of cancer progression. Also, exosomes derived from GCFs were taken up by GC cells in vitro and in vivo and exerted antitumor roles in GC. In addition, exosomal miRNA-34 inhibited GC cell proliferation and invasion in vitro and suppressed tumor growth in vivo. Furthermore, 16 genes were identified as potential downstream targeting genes of miRNA-34. Taken together, GCFs-derived exosomal miRNA-34 may be a promising targeting molecule for therapeutic strategies in GC.