Department of Biosciences, Mokpo National University, Joennam 58554, South Korea.
Department of Biomedicine, Health & Life Convergence Science, BK21 Four, Mokpo National University, Joennam 58554, South Korea.
Int J Med Sci. 2021 Jan 1;18(3):706-714. doi: 10.7150/ijms.51429. eCollection 2021.
Fhit gene is known as a genome "caretaker" and frequently inactivated by deletion or hypermethylation on the promoter in several cancers. In spite of several lines of evidence, the exact mechanism underlying Fhit-induced biology is relatively less studied. This study will focus the role of Fhit in regulating Lin28 and microRNAs (miRNAs) loop. : To this end, we employed Fhit overexpressing isogenic cell lines to conduct miRNA nanostring array, and differentially expressed miRNAs were identified. Using real-time PCR and Western blot analysis, expression levels of Lin28b or miRNAs were investigated in response to the overexpression of Fhit gene in H1299 lung cancer cells. A series of including gene nanostring analyses revealed that Lin28B protein was induced by Fhit gene overexpression, which consequently suppressed Let-7 miRNAs. Also, we found that miRNAs in miR-17/92 clusters are redundantly increased and there is an inverse correlation between Let-7 and miR-17/92 clusters in Fhit-expressing cells. Also, a series of in vitro experiments suggests that ELF-1- and/or STAT1-dependent Lin28b regulation is responsible for Let-7 induction in Fhit-expressing cancer cells. Based on the same experimental system proving that Fhit gene has a robust role in suppressing tumor progression and epithelial-mesenchymal transition, our data show that Fhit mediates the negative feedback between Lin28/Let-7 axis and miR-17/-92 miRNA although the physiological relevance of current interesting observation should be further investigated.
脆性组氨酸三联体（Fhit）基因被称为基因组“守护者”，在多种癌症中，其启动子经常因缺失或高甲基化而失活。尽管有几方面的证据，但 Fhit 诱导生物学的确切机制研究相对较少。本研究将重点研究 Fhit 在调节 Lin28 和 microRNAs（miRNAs）环中的作用。为此，我们采用了过表达 Fhit 的同基因细胞系进行 miRNA 纳米串阵列分析，鉴定出差异表达的 miRNAs。使用实时 PCR 和 Western blot 分析，研究了在 H1299 肺癌细胞中过表达 Fhit 基因时 Lin28b 或 miRNAs 的表达水平。一系列基因纳米串分析显示，Lin28B 蛋白被 Fhit 基因过表达诱导，进而抑制 Let-7 miRNAs。此外，我们发现 miR-17/92 簇中的 miRNAs 冗余增加，并且在 Fhit 表达细胞中 Let-7 和 miR-17/92 簇之间存在负相关。此外，一系列体外实验表明，ELF-1 和/或 STAT1 依赖性 Lin28b 调节是 Fhit 表达癌细胞中 Let-7 诱导的原因。基于证明 Fhit 基因在抑制肿瘤进展和上皮-间充质转化方面具有强大作用的相同实验系统，我们的数据表明，尽管当前有趣观察的生理相关性应进一步研究，但 Fhit 介导了 Lin28/Let-7 轴和 miR-17/-92 miRNA 之间的负反馈。
