Department of Gastrointestinal Cancer Biology, Tianjin Medical University Cancer Institute and Hospital, Tianjin, China.
Key Laboratory of Cancer Immunology and Biotherapy, Tianjin, China.
Cell Death Dis. 2021 Aug 5;12(8):774. doi: 10.1038/s41419-021-04061-4.
Circular RNAs (circRNAs) are a novel class of endogenous noncoding RNAs (ncRNAs) with a covalently closed loop structure. Accumulating evidence shows that circRNAs play vital roles in the growth, metastasis, treatment and prognosis of various cancers. However, the detailed functions and underlying mechanisms of circEVI5 (hsa_circ_0013162) in gastric cancer (GC) remain undocumented. In this study, the expression levels and prognostic value of circEVI5 were validated in GC tissue samples by using qRT-PCR. circEVI5 was significantly downregulated in GC tissues and cells, and low circEVI5 expression was correlated with poor prognosis. Next, in vitro CCK-8 assay, EdU incorporation assay, PI staining cell cycle assay, and in vivo xenograft mouse models were conducted to assess the functions of circEVI5. Gain of function experiments indicated that circEVI5 could inhibit GC cell proliferation and retard the cell cycle. Moreover, bioinformatics prediction showed that circEVI5 binds to miR-4793-3p, while FOXO1 may be a target of miR-4793-3p. Pull-down assays, RNA immunoprecipitation (RIP) assays, luciferase assays, and western blot were used to confirm the interactions between circEVI5, miR-4793-3p, and FOXO1. Functional assays demonstrated that circEVI5 suppressed the proliferation of GC by sponging miR-4793-3p and increasing FOXO1 expression levels. In conclusion, our study demonstrated that circEVI5 can bind miR-4793-3p as a ceRNA to eliminate the negative regulation of FOXO1, therefore suppressing GC proliferation.
环状 RNA（circRNAs）是一类具有共价闭合环结构的新型内源性非编码 RNA（ncRNAs）。越来越多的证据表明，circRNAs 在各种癌症的生长、转移、治疗和预后中发挥着重要作用。然而，circEVI5（hsa_circ_0013162）在胃癌（GC）中的详细功能和潜在机制仍未被记录。在本研究中，通过 qRT-PCR 验证了 circEVI5 在 GC 组织样本中的表达水平和预后价值。GC 组织和细胞中 circEVI5 的表达显著下调，低 circEVI5 表达与预后不良相关。接下来，进行了体外 CCK-8 测定、EdU 掺入测定、PI 染色细胞周期测定和体内异种移植小鼠模型实验，以评估 circEVI5 的功能。功能获得实验表明，circEVI5 可抑制 GC 细胞增殖并延缓细胞周期。此外，生物信息学预测表明，circEVI5 与 miR-4793-3p 结合，而 FOXO1 可能是 miR-4793-3p 的靶标。下拉实验、RNA 免疫沉淀（RIP）实验、荧光素酶实验和 Western blot 用于验证 circEVI5、miR-4793-3p 和 FOXO1 之间的相互作用。功能实验表明，circEVI5 通过海绵吸附 miR-4793-3p 并增加 FOXO1 表达水平来抑制 GC 增殖。总之，我们的研究表明，circEVI5 可以作为 ceRNA 结合 miR-4793-3p 来消除 FOXO1 的负调控，从而抑制 GC 增殖。
