Niu Yuchun, Ma Feng, Huang Weimei, Fang Shun, Li Man, Wei Ting, Guo Linlang
Department of Pathology Zhujiang Hospital, Southern Medical University, 253 Gongye Road, Guangzhou, 510282, People's Republic of China.
Department of Oncology, The First Affiliated Hospital of Hebei North University, Zhangjiakou, China.
Mol Cancer. 2017 Jan 9;16(1):5. doi: 10.1186/s12943-016-0575-6.
Taurine upregulated gene1 (TUG1) as a 7.1-kb lncRNA, has been shown to play an oncogenic role in various cancers. However, the biological functions of lncRNA TUG1 in small cell lung cancer (SCLC) remain unknown. The aim of this study is to explore the roles of TUG1 in cell growth and chemoresistance of SCLC and its possible molecular mechanism.
The expression of TUG1 in thirty-three cases of SCLC tissues and SCLC cell line were examined by quantitative RT-PCR (qRT-PCR). The functional roles of TUG1 in SCLC were demonstrated by CCK8 assay, colony formation assay, wound healing assay and transwell assay, flow cytometry analysis and in vivo study through siRNA or shRNA mediated knockdown. Western blot assays were used to evaluate gene and protein expression in cell lines. Chromatin immunoprecipitation (ChIP) and RNA binding protein immunoprecipitation (RIP) were performed to confirm the molecular mechanism of TUG1 involved in cell growth and chemoresistance of small cell lung cancer.
We found that TUG1 was overexpressed in SCLC tissues, and its expression was correlated with the clinical stage and the shorter survival time of SCLC patients. Moreover, downregulation of TUG1 expression could impair cell proliferation and increased cell sensitivity to anticancer drugs both in vitro and in vivo. We also discovered that TUG1 knockdown significantly promoted cell apoptosis and cell cycle arrest, and inhibited cell migration and invasion in vitro . We further demonstrated that TUG1 can regulate the expression of LIMK2b (a splice variant of LIM-kinase 2) via binding with enhancer of zeste homolog 2 (EZH2), and then promoted cell growth and chemoresistance of SCLC.
Together, these results suggested that TUG1 mediates cell growth and chemoresistance of SCLC by regulating LIMK2b via EZH2.
牛磺酸上调基因1（TUG1）作为一种7.1 kb的长链非编码RNA（lncRNA），已被证明在多种癌症中发挥致癌作用。然而，lncRNA TUG1在小细胞肺癌（SCLC）中的生物学功能仍不清楚。本研究的目的是探讨TUG1在SCLC细胞生长和化疗耐药中的作用及其可能的分子机制。
通过定量逆转录聚合酶链反应（qRT-PCR）检测33例SCLC组织和SCLC细胞系中TUG1的表达。通过CCK8法、集落形成试验、伤口愈合试验和transwell试验、流式细胞术分析以及通过siRNA或shRNA介导的敲低进行体内研究，证实TUG1在SCLC中的功能作用。采用蛋白质免疫印迹法检测细胞系中的基因和蛋白表达。进行染色质免疫沉淀（ChIP）和RNA结合蛋白免疫沉淀（RIP），以证实TUG1参与小细胞肺癌细胞生长和化疗耐药的分子机制。
我们发现TUG1在SCLC组织中高表达，其表达与SCLC患者的临床分期和较短生存时间相关。此外，下调TUG1表达可在体外和体内损害细胞增殖并增加细胞对抗癌药物的敏感性。我们还发现，敲低TUG1可显著促进细胞凋亡和细胞周期阻滞，并在体外抑制细胞迁移和侵袭。我们进一步证明，TUG1可通过与zeste同源物2（EZH2）增强子结合来调节LIMK2b（LIM激酶2的剪接变体）的表达，进而促进SCLC的细胞生长和化疗耐药。
总之，这些结果表明TUG1通过EZH2调节LIMK2b介导SCLC的细胞生长和化疗耐药。
