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