Department of Urology, Yiwu Central Hospital, Jinhua City, Zhejiang Province, China.
Eur Rev Med Pharmacol Sci. 2020 Sep;24(18):9303-9314. doi: 10.26355/eurrev_202009_23012.
MicroRNA-325 (miR-325) is a tumor suppressor in some cancers. However, the role of miR-325 in determining the chemosensitivity to cancer cells is still not clear. The aim of this study was to investigate the effect of miR-325 on reversing the cisplatin resistance of bladder cancer.
Cisplatin-resistant 5637 and T24 bladder cancer cell lines (5637/R and T24/R) were established through long term exposure of them to cisplatin. 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) assays were performed to evaluate the viability of 5637, 5637/R, T24, and T24/R cells. Quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) was used to examine the expression of miR-325 in these cell lines. The regulatory mechanism was confirmed by Western blot analysis and Luciferase reporter assays. After treatment with miR-325 and cisplatin, mitochondrial membrane potential (MMP) and apoptosis were measured using flow cytometry. Expression of hematopoietic cell-specific protein 1-associated protein X-1 (HAX-1) and activation of caspase-9, caspase-7, and caspase-3 were detected by Western blotting.
We found the downregulation of miR-325 in 5637/R and T24/R cells compared to their parental 5637 and T24 cells. Moreover, overexpression of miR-325 in cisplatin-resistant bladder cancer cells was found to increase the cytotoxicity of cisplatin to them. However, transfection with HAX-1 plasmid can abolish the effect of miR-325 on cisplatin. We, then, showed that overexpression of miR-325 suppressed the expression of HAX-1. Thus, miR-325 promoted the mitochondria collapse and cisplatin-induced apoptosis in bladder cancer cells.
Downregulation of miR-325 is responsible for the development of cisplatin resistance in bladder cancer. Overexpression of miR-325 may represent a novel strategy to reverse the chemoresistance of bladder cancer.
MicroRNA-325（miR-325）在某些癌症中是一种肿瘤抑制因子。然而，miR-325 对癌细胞化疗敏感性的作用尚不清楚。本研究旨在探讨 miR-325 逆转膀胱癌顺铂耐药的作用。
通过长期暴露于顺铂，建立了顺铂耐药的 5637 和 T24 膀胱癌细胞系（5637/R 和 T24/R）。3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴盐（MTT）测定法评估 5637、5637/R、T24 和 T24/R 细胞的活力。定量实时聚合酶链反应（qRT-PCR）用于检测这些细胞系中 miR-325 的表达。通过 Western blot 分析和荧光素酶报告基因检测证实了调控机制。用 miR-325 和顺铂处理后，用流式细胞术测量线粒体膜电位（MMP）和凋亡。Western blot 检测造血细胞特异性蛋白 1 相关蛋白 X-1（HAX-1）的表达和 caspase-9、caspase-7 和 caspase-3 的激活。
我们发现与亲本 5637 和 T24 细胞相比，5637/R 和 T24/R 细胞中 miR-325 的表达下调。此外，在顺铂耐药的膀胱癌细胞中转染 miR-325 发现增加了顺铂对它们的细胞毒性。然而，HAX-1 质粒的转染可以消除 miR-325 对顺铂的作用。然后，我们表明过表达 miR-325 抑制了 HAX-1 的表达。因此，miR-325 促进了膀胱癌细胞中线粒体崩溃和顺铂诱导的凋亡。
miR-325 的下调导致膀胱癌顺铂耐药的发展。过表达 miR-325 可能代表一种逆转膀胱癌化疗耐药的新策略。
