突变型 K-Ras 抑制的 miR-199b 的恢复抑制 K-Ras 突变型非小细胞肺癌的进展。
Restoration of mutant K-Ras repressed miR-199b inhibits K-Ras mutant non-small cell lung cancer progression.
机构信息
Department of Thoracic Surgery, Daping Hospital and Research Institute of Surgery, Third Military Medical University, Chongqing, 400042, China.
Laboratory of Toxicology, College of Veterinary Medicine, Seoul National University, Seoul, 151-742, South Korea.
出版信息
J Exp Clin Cancer Res. 2019 Apr 15;38(1):165. doi: 10.1186/s13046-019-1170-7.
BACKGROUND
miRNAs play crucial role in the progression of K-Ras-mutated nonsmall cell lung cancer (NSCLC). However, most studies have focused on miRNAs that target K-Ras. Here, we investigated miRNAs regulated by mutant K-Ras and their functions.
METHODS
miRNAs regulated by mutant K-Ras were screened using miRNA arrays. miR-199b expression levels were measured by qRT-PCR. The protein expression levels were measured using Western blot and immunohistochemistry. The effects of miR-199b on NSCLC were examined both in vitro and in vivo by overexpressing or inhibiting miR-199b. DNA methylation was measured by bisulfite sequencing.
RESULTS
An inverse correlation was observed between K-Ras mutation status and miR-199b levels in NSCLC specimens and cell lines. The inhibition of miR-199b stimulated NSCLC growth and metastasis, while restoration of miR-199b suppressed K-Ras mutation-driven lung tumorigenesis as well as K-Ras-mutated NSCLC growth and metastasis. miR-199b inactivated ERK and Akt pathways by targeting K-Ras, KSR2, PIK3R1, Akt1, and Rheb1. Furthermore, we determined that mutant K-Ras inhibits miR-199b expression by increasing miR-199b promoter methylation.
CONCLUSION
Our findings suggest that mutant K-Ras plays an oncogenic role through downregulating miR-199b in NSCLC and that overexpression of miR-199b is a novel strategy for the treatment of K-Ras-mutated NSCLC.
背景
miRNA 在 K-Ras 突变型非小细胞肺癌（NSCLC）的进展中发挥着关键作用。然而，大多数研究都集中在靶向 K-Ras 的 miRNA 上。在这里，我们研究了受突变型 K-Ras 调控的 miRNA 及其功能。
方法
使用 miRNA 芯片筛选受突变型 K-Ras 调控的 miRNA。通过 qRT-PCR 测量 miR-199b 的表达水平。通过 Western blot 和免疫组织化学测量蛋白表达水平。通过过表达或抑制 miR-199b 在体外和体内检查 miR-199b 对 NSCLC 的影响。通过亚硫酸氢盐测序测量 DNA 甲基化。
结果
在 NSCLC 标本和细胞系中，观察到 K-Ras 突变状态与 miR-199b 水平之间呈负相关。抑制 miR-199b 刺激 NSCLC 生长和转移，而恢复 miR-199b 抑制 K-Ras 突变驱动的肺肿瘤发生以及 K-Ras 突变型 NSCLC 的生长和转移。miR-199b 通过靶向 K-Ras、KSR2、PIK3R1、Akt1 和 Rheb1 使 ERK 和 Akt 通路失活。此外，我们确定突变型 K-Ras 通过增加 miR-199b 启动子甲基化抑制 miR-199b 的表达。
结论
我们的研究结果表明，突变型 K-Ras 通过下调 NSCLC 中的 miR-199b 发挥致癌作用，并且过表达 miR-199b 是治疗 K-Ras 突变型 NSCLC 的一种新策略。
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