Department of General Surgery, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, Jiangsu 215002, P.R. China.
Int J Mol Med. 2018 Nov;42(5):2503-2514. doi: 10.3892/ijmm.2018.3864. Epub 2018 Sep 7.
MicroRNA‑7 (miR‑7) is a non‑coding RNA that inhibits colorectal cancer (CRC) cell proliferation, migration and invasion. miR‑7 effectively silences TYRO3 expression, and the close association between TYRO3 and CRC has previously been reported. Therefore, the present study aimed to assess the roles and molecular mechanisms of TYRO3 and miR‑7 in the development of CRC. The expression levels of miR‑7 and TYRO3 in CRC tissues and cell lines were detected by reverse transcription‑quantitative polymerase chain reaction. A dual‑luciferase reporter assay was also performed to confirm whether TYRO3 was a target of miR‑7. The effect of miR‑7 and TYRO3 on cell proliferation, migration and invasion was detected in vitro with MTT, wound healing and cell invasion assays, respectively. The expression of proteins associated with the phosphoinositide 3‑kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway was detected by western blot analysis. The results indicated that the expression of miR‑7 was downregulated and the levels of TYRO3 were gradually increased in CRC tissues and cell lines. TYRO3 was identified as a functional target of miR‑7, and its expression was negatively regulated by miR‑7 in CRC cell lines. The functional studies demonstrated that miR‑7 knockdown promoted the proliferation, migration and invasion of CRC cells, while knockdown of TYRO3 repressed these biological processes. In addition, pathway analyses revealed that the oncogenic effect of TYRO3 was associated with PI3K/AKT/mTOR pathway inhibition. In conclusion, the data suggested that miR‑7 promoted the development of CRC by targeting oncogenic TYRO3, which may be mediated by inhibition of the PI3K/AKT/mTOR signaling pathway. Thus, miR‑7 may serve as an independent prognostic biomarker in patients with CRC.
微小 RNA-7（miR-7）是一种非编码 RNA，可抑制结直肠癌（CRC）细胞的增殖、迁移和侵袭。miR-7 可有效沉默 TYRO3 的表达，先前已有报道 TYRO3 与 CRC 密切相关。因此，本研究旨在评估 TYRO3 和 miR-7 在 CRC 发生发展过程中的作用和分子机制。采用逆转录-定量聚合酶链反应检测 CRC 组织和细胞系中 miR-7 和 TYRO3 的表达水平。还进行了双荧光素酶报告基因检测，以证实 TYRO3 是否是 miR-7 的靶基因。采用 MTT、划痕愈合和细胞侵袭实验分别检测 miR-7 和 TYRO3 对细胞增殖、迁移和侵袭的影响。采用 Western blot 分析检测与磷酸肌醇 3-激酶/蛋白激酶 B/雷帕霉素靶蛋白（PI3K/AKT/mTOR）通路相关的蛋白表达。结果表明，miR-7 在 CRC 组织和细胞系中的表达下调，而 TYRO3 的水平逐渐升高。TYRO3 被鉴定为 miR-7 的功能性靶基因，并且在 CRC 细胞系中，其表达受 miR-7 的负调控。功能研究表明，miR-7 敲低促进了 CRC 细胞的增殖、迁移和侵袭，而 TYRO3 的敲低则抑制了这些生物学过程。此外，通路分析表明，TYRO3 的致癌作用与 PI3K/AKT/mTOR 通路抑制有关。综上所述，数据表明，miR-7 通过靶向致癌基因 TYRO3 促进 CRC 的发展，这可能是通过抑制 PI3K/AKT/mTOR 信号通路介导的。因此，miR-7 可作为 CRC 患者的独立预后生物标志物。
