OncoTargets and Therapy (Feb 2019)
Overexpressed long noncoding RNA TUG1 affects the cell cycle, proliferation, and apoptosis of pancreatic cancer partly through suppressing RND3 and MT2A
Abstract
Bingqing Hui,1,2,* Yetao Xu,3,* Benpeng Zhao,4,* Hao Ji,1,2 Zhonghua Ma,1,2 Shufen Xu,1,2 ZhenYu He,1,5 Keming Wang,1,2 Jianwei Lu6 1Department of Oncology, Second Affiliated Hospital, Nanjing Medical University, Nanjing 210000, Jiangsu, China; 2Department of Oncology, Second Clinical Medical College of Nanjing Medical University, Nanjing 210000, Jiangsu, China; 3Department of Obstetrics and Gynecology, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu, China; 4Basic Medicine Faculty of Shanghai Jiaotong University, Core Facility of Basic Medical Sciences, Shanghai 200000, China; 5Department of General Surgery, Second Affiliated Hospital, Nanjing Medical University, Nanjing 210000, Jiangsu, China; 6Department of Medical Oncology, Jiangsu Cancer Hospital, Jiangsu Institute of Cancer Research, Nanjing Medical University Affiliated Cancer Hospital, Nanjing 210000, Jiangsu, China *These authors contributed equally to this work Background: Long noncoding RNAs (lncRNAs) are involved in various human diseases, including cancers. However, their mechanisms remain undocumented. We investigated alterations in lncRNA that may be related to pancreatic cancer (PC) through analysis of microarray data. Methods: In the present study, quantitative real-time PCR analysis was used to examine the expression of taurine upregulated 1 (TUG1) in PC tissue samples and PC cell lines. In PC cell lines, MTT assays, colony formation assays, and flow cytometry were used to investigate the effects of TUG1 on proliferation, cell cycle regulation, and apoptosis. Moreover, we established a xenograft model to assess the effect of TUG1 on tumor growth in vivo. The molecular mechanism of potential target genes was detected through nuclear separation experiments, RNA immunoprecipitation (RIP), chromatin immunoprecipitation assays (ChIP), and other experimental methods. Results: The findings suggest that the abnormally high expression of TUG1 in PC tissues was associated with tumor size and pathological stage. Knockdown of TUG1 blocked the cell cycle and accelerated apoptosis, thereby inhibiting the proliferation of PC cells. In addition, RIP experiments showed that TUG1 can recruit enhancer of zeste homolog 2 (EZH2) to the promoter regions of Rho family GTPase 3 (RND3) and metallothionein 2A (MT2A) and inhibit their expression at the transcriptional level. Furthermore, ChIP experiments demonstrated that EZH2 could bind to the promoter regions of RND3 and MT2A. The knockdown of TUG1 reduced this binding capacity. Conclusion: In conclusion, our data suggest that TUG1 may regulate the expression of PC-associated tumor suppressor genes at the transcriptional level and these may become potential targets for the diagnosis and treatment of PC. Keywords: LncRNA, ncRNA, regulate, mechanism, cancer, EZH2, transcriptional level, tumor suppressor genes
