Department of Urology, The Second Affiliated Hospital of Kunming Medical University, Yunnan Institute of Urology, Kunming 650101, China.
Department of Urology, The Second Affiliated Hospital of Kunming Medical University, Yunnan Institute of Urology, Kunming 650101, China.
Exp Cell Res. 2018 Dec 15;373(1-2):188-197. doi: 10.1016/j.yexcr.2018.10.013. Epub 2018 Oct 25.
MicroRNA-98(miR-98) has been shown to be critical for tumorigenesis, however its involvement in bladder cancer are unclear. The present study aims to investigate the expression, biological roles and potential mechanisms of miR-98 in human bladder cancer. We found that miR-98 was upregulated in bladder urothelial carcinoma tissues compared with adjacent normal tissues. In addition, miR-98 expression was higher in bladder cancer cell lines than in uroepithelial cell line SV-HUC-1. Functional studies revealed that miR-98 mimic promoted proliferation of T24 cells while miR-98 inhibitor inhibited proliferation of BIU-87 cells. Moreover, miR-98 mimic increased cisplatin/doxorubicin resistance and inhibited apoptosis in T24 cells, while miR-98 inhibitor decreased chemoresistance and facilitated apoptosis in BIU-87 cells. Further experiments using MitoTracker and JC-1 staining showed that miR-98 could regulate mitochondrial fission/fusion balance and mitochondrial membrane potential. Western blot showed that miR-98 upregulated cyclin D1, p-Drp1 and Drp1. Using luciferase reporter assay, we demonstrated that LASS2 acted as a direct target of miR-98. LASS2 overexpression induced mitochondrial fusion and downregulated mitochondrial potential, with decreased p-Drp1 status. Additionally, LASS2 siRNA abrogated the effects of miR-98 mimic on Drp1phosphorylation and chemoresistance. We also found a negative correlation between LASS2 and miR-98 in bladder cancer tissues. In conclusion, our study demonstrates that miR-98 targets LASS2 and regulates bladder cancer chemoresistance through modulation of mitochondrial function.
微小 RNA-98(miR-98) 已被证明对肿瘤发生至关重要，但它在膀胱癌中的作用尚不清楚。本研究旨在探讨 miR-98 在人膀胱癌中的表达、生物学作用及其潜在机制。我们发现 miR-98 在膀胱尿路上皮癌组织中上调，而在相邻正常组织中下调。此外，miR-98 在膀胱癌细胞系中的表达高于尿上皮细胞系 SV-HUC-1。功能研究表明，miR-98 模拟物促进了 T24 细胞的增殖，而 miR-98 抑制剂抑制了 BIU-87 细胞的增殖。此外，miR-98 模拟物增加了 T24 细胞对顺铂/阿霉素的耐药性并抑制了细胞凋亡，而 miR-98 抑制剂降低了 BIU-87 细胞的耐药性并促进了细胞凋亡。使用 MitoTracker 和 JC-1 染色的进一步实验表明，miR-98 可以调节线粒体分裂/融合平衡和线粒体膜电位。Western blot 显示 miR-98 上调了细胞周期蛋白 D1、p-Drp1 和 Drp1。通过荧光素酶报告基因实验，我们证明了 LASS2 是 miR-98 的直接靶基因。LASS2 过表达诱导线粒体融合并下调线粒体膜电位，降低 p-Drp1 状态。此外，LASS2 siRNA 消除了 miR-98 模拟物对 Drp1 磷酸化和化疗耐药性的影响。我们还发现膀胱癌组织中 LASS2 和 miR-98 之间存在负相关。总之，本研究表明，miR-98 靶向 LASS2，并通过调节线粒体功能调节膀胱癌的化疗耐药性。
