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Abstract：
Circular RNAs (circRNAs) represent a class of RNA molecules characterized by their covalently closed structures. There are three types of circRNAs, namely exonic circRNAs, exon‑intron circRNAs and circular intronic RNAs. To date, four distinct mechanisms have been unveiled through which circRNAs exert their functional influence, including serving as microRNA (miRNA) sponges, interacting with RNA binding proteins (RBPs), modulating parental gene transcription and acting as templates for translation. Of note, among these mechanisms, the miRNA/RBP sponge function has been the most investigated one. Recent research has uncovered the presence of various proteins or peptides encoded by circRNA. CircRNAs are translated independent of the 5\' cap and 3\' polyA tail, which are typical elements for linear RNA translation. Some unique elements, such as internal ribosome entry sites and N‑methyladenosine modifications, facilitate the initiation of translation. These circRNA‑encoded proteins or peptides participate in diverse signalling pathways and act as important regulators in carcinogenesis by influencing cell proliferation, migration, apoptosis and other key processes. Consequently, circRNA‑encoded proteins or peptides have great potential as therapeutic targets for anticancer drugs. The present comprehensive review aimed to systematically summarize the current understanding of circRNA‑encoded proteins or peptides and to unveil their roles in carcinogenesis.
摘要：
环状RNA(circularRNAs,circRNAs)代表一类以其共价闭合结构为特征的RNA分子。有三种类型的circRNAs，即外显子circRNAs，外显子内含子circRNAs和环状内含子RNAs。迄今为止,已经揭示了四种不同的机制，通过这些机制，circRNAs发挥其功能影响，包括作为microRNA（miRNA）海绵，与RNA结合蛋白（RBPs）相互作用，调节亲本基因转录并充当翻译模板。值得注意的是，在这些机制中，miRNA/RBP海绵功能研究最多。最近的研究已经发现了由circRNA编码的各种蛋白质或肽的存在。CircRNAs的翻译独立于5'cap和3'polyA尾，它们是线性RNA翻译的典型元件。一些独特的元素，例如内部核糖体进入位点和N-甲基腺苷修饰，促进翻译的启动。这些circRNA编码的蛋白质或肽参与不同的信号通路，并通过影响细胞增殖在癌变中起重要的调节因子，迁移,细胞凋亡和其他关键过程。因此,circRNA编码的蛋白质或肽作为抗癌药物的治疗靶标具有巨大潜力。本综合综述旨在系统地总结目前对circRNA编码的蛋白质或肽的理解，并揭示它们在致癌作用中的作用。
