Cancer and Anticancer Drug Research Center, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China.
Affiliated Yueqing Hospital, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China.
Proc Natl Acad Sci U S A. 2020 Feb 25;117(8):4347-4357. doi: 10.1073/pnas.1917531117. Epub 2020 Feb 10.
Lung cancer is the leading cause of cancer-related deaths worldwide and non-small cell lung cancer (NSCLC) accounts for over 80% of lung cancer cases. The RNA binding protein, QKI, belongs to the STAR family and plays tumor-suppressive functions in NSCLC. QKI-5 is a major isoform of QKIs and is predominantly expressed in NSCLC. However, the underlying mechanisms of QKI-5 in NSCLC progression remain unclear. We found that QKI-5 regulated microRNA (miRNA), miR-196b-5p, and its expression was significantly up-regulated in NSCLC tissues. Up-regulated miR-196b-5p promotes lung cancer cell migration, proliferation, and cell cycle through directly targeting the tumor suppressors, GATA6 and TSPAN12. Both GATA6 and TSPAN12 expressions were down-regulated in NSCLC patient tissue samples and were negatively correlated with miR-196b-5p expression. Mouse xenograft models demonstrated that miR-196b-5p functions as a potent onco-miRNA, whereas TSPAN12 functions as a tumor suppressor in NSCLC in vivo. QKI-5 bound to miR-196b-5p and influenced its stability, resulting in up-regulated miR-196b-5p expression in NSCLC. Further analysis showed that hypomethylation in the promoter region enhanced miR-196b-5p expression in NSCLC. Our findings indicate that QKI-5 may exhibit novel anticancer mechanisms by regulating miRNA in NSCLC, and targeting the QKI5∼miR-196b-5p∼GATA6/TSPAN12 pathway may enable effectively treating some NSCLCs.
肺癌是全球癌症相关死亡的主要原因,非小细胞肺癌(NSCLC)占肺癌病例的 80%以上。RNA 结合蛋白 QKI 属于 STAR 家族,在 NSCLC 中发挥肿瘤抑制作用。QKI-5 是 QKIs 的主要亚型,在 NSCLC 中主要表达。然而,QKI-5 在 NSCLC 进展中的潜在机制尚不清楚。我们发现 QKI-5 调节 microRNA(miRNA),miR-196b-5p,其在 NSCLC 组织中的表达显著上调。上调的 miR-196b-5p 通过直接靶向肿瘤抑制因子 GATA6 和 TSPAN12,促进肺癌细胞迁移、增殖和细胞周期。GATA6 和 TSPAN12 的表达在 NSCLC 患者组织样本中下调,与 miR-196b-5p 的表达呈负相关。小鼠异种移植模型表明,miR-196b-5p 在体内作为一种有效的癌基因 miRNA,而 TSPAN12 在 NSCLC 中作为一种肿瘤抑制因子。QKI-5 与 miR-196b-5p 结合并影响其稳定性,导致 NSCLC 中 miR-196b-5p 表达上调。进一步分析表明,启动子区域的低甲基化增强了 NSCLC 中 miR-196b-5p 的表达。我们的研究结果表明,QKI-5 可能通过调节 NSCLC 中的 miRNA 发挥新的抗癌机制,针对 QKI5∼miR-196b-5p∼GATA6/TSPAN12 通路可能有效治疗某些 NSCLC。