Department of Urology, The Third Medical Center of Chinese People's Liberation Army General Hospital, Beijing, China.
State Key Laboratory of Cancer Biology, Department of Biochemistry and Molecular Biology, The Fourth Military Medical University, Xi'an, Shaanxi, China.
Ann Clin Lab Sci. 2021 Sep;51(5):625-637.
microRNAs may play essential roles in the development and drug resistance of non-small cell lung cancer (NSCLC). However, their functions and mechanisms are not fully understood. Our goal was to define the role of miR-145-5p in the gefitinib resistance of NSCLC.
An A549 gefitinib-resistant cell line and xenograft nude mice were used in this study. The expression of miR-145-5p and its targets, NRAS and MEST, were detected and measured by qPCR, Western blot, RNA-FISH, or immunofluorescence analysis.
miR-145-5p was downregulated in gefitinib-resistant A549 cells (A549/Gef R). Overexpression of miR-145-5p enhanced the sensitivity to gefitinib and inhibited cell proliferation and invasion in A549/Gef R. miR-145-5p was also significantly reduced in LUAD and LUSC clinical samples and closely associated with a favorable prognosis, according to the UALCAN and TCGA databases. Moreover, NRAS and MEST were found to be downstream target genes of miR-145-5p and to function as oncogenes in NSCLC samples, and gefitinib resistance could be improved following the interference of these two molecules.
miR-145-5p improves the sensitivity of acquired gefitinib-resistant cells to gefitinib via inhibiting NRAS and MEST expression. The miR 145-5p-NRAS/MEST axis in NSCLC provides insights for the development of a NRAS/MEST targeting therapeutic approach to overcome gefitinib resistance in NSCLC patients.
microRNAs 可能在非小细胞肺癌（NSCLC）的发生和耐药中发挥重要作用。然而，其功能和机制尚不完全清楚。我们的目标是定义 miR-145-5p 在 NSCLC 吉非替尼耐药中的作用。
本研究使用了 A549 吉非替尼耐药细胞系和异种移植裸鼠。通过 qPCR、Western blot、RNA-FISH 或免疫荧光分析检测和测量 miR-145-5p 及其靶标 NRAS 和 MEST 的表达。
miR-145-5p 在吉非替尼耐药 A549 细胞（A549/Gef R）中下调。miR-145-5p 的过表达增强了 A549/Gef R 对吉非替尼的敏感性，并抑制了细胞增殖和侵袭。根据 UALCAN 和 TCGA 数据库，miR-145-5p 在 LUAD 和 LUSC 临床样本中也显著降低，并与良好的预后密切相关。此外，NRAS 和 MEST 被发现是 miR-145-5p 的下游靶基因，并且在 NSCLC 样本中作为癌基因发挥作用，干扰这两个分子可以改善 gefitinib 耐药性。
miR-145-5p 通过抑制 NRAS 和 MEST 的表达提高了获得性 gefitinib 耐药细胞对 gefitinib 的敏感性。NSCLC 中的 miR-145-5p-NRAS/MEST 轴为开发针对 NRAS/MEST 的治疗方法以克服 NSCLC 患者对 gefitinib 的耐药性提供了思路。
