非小细胞肺癌（NSCLC）占肺癌病例的80%以上，患者5年生存率仍不理想。 MicroRNA (miRNA) 是小型内源性非编码 RNA，被认为是肿瘤发生（包括 NSCLC）的重要转录后调节因子。在本研究中，我们旨在研究miR-3074-5p在NSCLC细胞中的生物学作用及其潜在的分子机制。我们发现人类 NSCLC 标本和细胞系中 miR-3074-5p 表达降低。此外，miR-3074-5p过表达抑制细胞增殖、迁移和侵袭，并诱导细胞凋亡和细胞周期停滞。此外，miR-3074-5p过表达不仅抑制肿瘤生长，而且在体外和体内增强紫杉醇（PTX）对NSCLC细胞的抗肿瘤作用。转录组测序分析显示，miR-3074-5p过表达后差异表达的基因，在表达水平下降最显着的基因中，酪氨酸3-单加氧酶/色氨酸5-单加氧酶激活蛋白zeta（YWHAZ）是miR的靶标-3074-5p。通过蛋白质印迹和双荧光素酶报告基因测定验证了 miR-3074-5p 对 YWHAZ 表达的调节作用。 YWHAZ 过表达可逆转 A549 细胞生长、迁移和侵袭的抑制。此外，我们发现 PTX 刺激 YWHAZ 和 Hsp27 蛋白的表达，并促进 Hsp27 的磷酸化（在 S15 和 S78）。 YWHAZ被证实与A549细胞中的Hsp27相互作用，下调YWHAZ表达促进了Hsp27蛋白的降解。综上所述，这些结果表明 miR-3074-5p/YWHAZ/Hsp27 轴可能是 NSCLC 治疗的新型治疗靶点。版权所有 © 2024 Elsevier B.V. 保留所有权利。

Non-small cell lung cancer (NSCLC) accounts for more than 80% of lung cancer cases, and the 5-year survival rate of patients remains unsatisfactory. MicroRNAs (miRNAs) are small endogenous noncoding RNAs that are considered essential posttranscriptional regulators of tumorigenesis, including NSCLC. In this study, we aimed to investigate the biological role of miR-3074-5p in NSCLC cells and the underlying molecular mechanisms. We showed that miR-3074-5p expression was decreased in human NSCLC specimens and cell lines. Moreover, miR-3074-5p overexpression inhibited cell proliferation, migration and invasion and induced apoptosis and cell cycle arrest. In addition, miR-3074-5p overexpression not only suppressed tumor growth but also enhanced the antitumor effect of paclitaxel (PTX) on NSCLC cells in vitro and in vivo. A transcriptome sequencing assay revealed genes that were differentially expressed after miR-3074-5p overexpression, and among the genes whose expression levels were most significantly decreased, tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein zeta (YWHAZ) was a target of miR-3074-5p. The regulatory effect of miR-3074-5p on YWHAZ expression was verified by Western blotting and dual-luciferase reporter assays. The inhibition of A549 cell growth, migration and invasion was reversed by YWHAZ overexpression. Furthermore, we showed that PTX stimulated the expression of the YWHAZ and Hsp27 proteins and promoted the phosphorylation of Hsp27 (at S15 and S78). YWHAZ was confirmed to interact with Hsp27 in A549 cells, and downregulating YWHAZ expression promoted the degradation of the Hsp27 protein. Taken together, these results suggest that the miR-3074-5p/YWHAZ/Hsp27 axis may be a novel therapeutic target for NSCLC treatment.Copyright © 2024 Elsevier B.V. All rights reserved.