Lv Dong, Xiang Ying, Yang Qi, Yao Juncheng, Dong Qiang
Department of Urology, West China Hospital, Sichuan University, Chengdu, Sichuan, People's Republic of China.
Department of Urology, Eastern Hospital, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, Sichuan, People's Republic of China.
Onco Targets Ther. 2020 Jun 19;13:5857-5868. doi: 10.2147/OTT.S254634. eCollection 2020.
Clear cell renal cell carcinoma (ccRCC) is a common urological carcinoma in adults. Long non-coding RNA (lncRNA) taurine-upregulated gene 1 (TUG1) has been reported to be involved in the progression of diverse human cancers, including renal cell carcinoma (RCC). However, the biological mechanism of TUG1 was rarely reported in ccRCC.
The levels of TUG1, microRNA miR-31-5p and flotillin 1 (FLOT1) in ccRCC tissues and cells were detected by qRT-PCR. The interactions between miR-31-5p and TUG1 or FLOT1 were predicted by starBase v2.0 and TargetScan, respectively, which were further validated by RIP assay and RNA pull-down assay. Cell counting kit-8 (CCK-8), flow cytometry and Western blot were used to assess the effects of TUG1 on cell viability, apoptosis rate and the relative protein expression levels in ccRCC cells. In addition, the xenograft tumor assay was conducted to further verify the functions of TUG1 in ccRCC in vivo.
TUG1 was dramatically up-regulated in ccRCC tissues and cells. TUG1 silencing inhibited cell proliferation and promoted cell apoptosis, autophagy in 786-0 and A498 cells. In addition, TUG1 depletion repressed tumor growth in vivo. Moreover, miR-31-5p was validated as a direct target of TUG1, and microRNA miR-31-5p inhibitor mitigated the effects of TUG1 knockdown on ccRCC progression. Furthermore, FLOT1 was verified to be negatively interacted with miR-31-5p. FLOT1 overexpression attenuated miR-31-5p-mediated inhibitory effect on cell proliferation and promotion effects on cell apoptosis, autophagy. The restoration experiment implicated that TUG1 positively modulated FLOT1 expression by sponging miR-31-5p.
All data demonstrated that TUG1 promotes cell proliferation and inhibits cell apoptosis and autophagy in ccRCC by miR-31-5p/FLOT1 axis, which may provide a therapeutic target for ccRCC patients.
透明细胞肾细胞癌（ccRCC）是成人常见的泌尿系统肿瘤。据报道，长链非编码RNA（lncRNA）牛磺酸上调基因1（TUG1）参与包括肾细胞癌（RCC）在内的多种人类癌症的进展。然而，TUG1在ccRCC中的生物学机制鲜有报道。
采用qRT-PCR检测ccRCC组织和细胞中TUG1、微小RNA miR-31-5p和浮舰蛋白1（FLOT1）的水平。分别通过starBase v2.0和TargetScan预测miR-31-5p与TUG1或FLOT1之间的相互作用，并通过RNA免疫沉淀实验（RIP）和RNA下拉实验进一步验证。使用细胞计数试剂盒-8（CCK-8）、流式细胞术和蛋白质免疫印迹法评估TUG1对ccRCC细胞活力、凋亡率和相关蛋白表达水平的影响。此外，进行异种移植瘤实验以进一步验证TUG1在ccRCC体内的功能。
TUG1在ccRCC组织和细胞中显著上调。TUG1沉默抑制786-0和A498细胞的增殖并促进细胞凋亡和自噬。此外，TUG1缺失在体内抑制肿瘤生长。而且，miR-31-5p被证实为TUG1的直接靶点，微小RNA miR-31-5p抑制剂减轻了TUG1敲低对ccRCC进展的影响。此外，FLOT1被证实与miR-31-5p存在负向相互作用。FLOT1过表达减弱了miR-31-5p介导的对细胞增殖的抑制作用以及对细胞凋亡和自噬的促进作用。回复实验表明TUG1通过海绵吸附miR-31-5p正向调节FLOT1表达。
所有数据表明，TUG1通过miR-31-5p/FLOT1轴促进ccRCC细胞增殖并抑制细胞凋亡和自噬，这可能为ccRCC患者提供一个治疗靶点。
