环状RNA在肿瘤中的表达与功能

环状RNA(circular RNA,circRNA)是一类闭合环状的内源RNA分子,广泛存在于不同物种及多种人体细胞中,具有丰富性、稳定性和组织特异性等特点。人体细胞中的circRNA主要可分为外显子circRNA、环状内含子RNA和外显子-内含子circRNA等。与正常组织相比,circRNA在多种肿瘤组织中异常表达,并具有作为微小RNA(microRNA,miRNA)海绵调控miRNA、结合蛋白质、参与翻译等功能。虽然circRNA在肿瘤中异常表达的具体机制尚不明确,但其在食管鳞状细胞癌、胃癌、结直肠癌、肝细胞癌、神经胶质瘤等多种肿瘤发生、发展的分子通路中具有重要作用,并有望成为全新的肿瘤标志物和治疗靶点。circRNA领域的发展日新月异,本文根据最新研究报道,就circRNA的基本特征、异常表达机制、调控肿瘤的机制及其在多种肿瘤中发挥的作用作一综述。

Expression and Functions of Circular RNAs in Cancer

Circular RNAs (circRNAs) are closed circular endogenous RNA molecules in various cells of different species. They are abundant, stable and have tissue specificity. circRNAs in human cells are divided into exonic circRNA, circular intronic RNA and exon-intron circRNA. circRNAs are aberrantly expressed in a variety of tumor tissues compared with the normal counterparts, and can serve as microRNA sponges, bind to RNA-binding proteins, and even be translated into polypeptides. Although the mechanism behind the aberrant expression of circRNAs in cancer is not clear, they play a critical role in the initiation and progression of different kinds of cancer like esophageal squamous cell carcinoma, gastric cancer, colorectal cancer, hepatocellular carcinoma, and glioma. circRNAs are also expected to be novel cancer biomarkers as well as therapeutic targets. This review summarizes recent literatures, focusing on various aspects of circRNAs, including their characteristics, mechanisms of their aberrant expression, their molecular functions in cancer, and their specific roles in several kinds of cancer.