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MicroRNAs(miRNAs)是一类内源性、非编码的单链小分子RNA,作用广泛,参与生命活动中的一系列重要进程,并与肿瘤的发生、发展密切相关。miRNA let-7是最早发现的miRNA之一,是线虫时序性发育的关键性调控因子;在哺乳动物中调节多种细胞增殖,且在细胞周期调节中起关键作用。let-7与人类多种癌症的发生、发展有关,其中与肺癌的关系最为密切;hsa-let-7在肺癌中表达显著降低,在非小细胞肺癌(NSCLC)中尤为多见,其低表达可能与肿瘤预后不良有关,而高表达则直接抑制肺癌生长;let-7作为肿瘤抑制因子负性调控多种癌基因,如RAS、高迁移率蛋白A2基因(high mobility group proteinA2,HMGA2)等;同时也负性调控多种细胞周期调节因子,如CDC25A、CDK6、Cyclin D2。let-7在肺癌组织中起到了肿瘤抑制因子的作用,有望成为肺癌基因治疗和预后判断的一个新靶标。
MicroRNAs (miRNAs) are a class of endogenous, non-coding single-stranded small molecule RNAs that are widely involved in a series of important processes in life activities and are closely related to tumorigenesis and development. The miRNA let-7 is one of the earliest miRNAs found and is a key regulator of the temporal development of nematodes. It regulates various cell proliferation in mammals and plays a key role in the regulation of the cell cycle. let-7 is related to the occurrence and development of many kinds of human cancers, of which lung cancer is most closely related. The expression of hsa-let-7 in lung cancer is significantly reduced, especially in non-small cell lung cancer (NSCLC) May be related to the poor prognosis of tumor, while high expression directly inhibits the growth of lung cancer; let-7 as a tumor suppressor negatively regulates a variety of oncogenes, such as RAS, high mobility group protein A2 (HMGA2) It also negatively regulates a variety of cell cycle regulators, such as CDC25A, CDK6, and Cyclin D2. let-7 plays a role of tumor suppressor in lung cancer and is expected to become a new target for lung cancer gene therapy and prognosis.