Methylseleninic acid activates Keap1/Nrf2 pathway via up-regulating miR-200a in human oesophageal squamous cell carcinoma cells

Oesophageal squamous cell carcinoma (ESCC) occurs at a very high rates in certain regions of China. There are increasing evidences demonstrating that selenium could act as a potential anti-oesophageal cancer agent, but the precise mechanisms involved are still not completely understood. Methylseleninic acid (MSA), as a potent second-generation selenium compound, is a promising chemopreventive agent. Previous studies demonstrated that the kelch-like ECH-associated protein 1 (Keap1)/nuclear factor E2-related factor 2 (Nrf2) system plays a critical role in cancer prevention, but little is known about its association with MSA in ESCC cells. In the present study, we observed that MSA treatment significantly down-regulated Keap1, induced nuclear accumulation of Nrf2 and enhance the antioxidant response element (ARE) promoter activity in ESCC cells. MSA could also significantly induce miR-200a expression and inhibit Keap1 directly. Antagomir-200a could attenuate MSA treatment-induced Keap1 down-regulation in ESCC cells. Moreover, MSA-induced miR-200a expression was dependent on the mediation of Krüpple-like factor 4 (KLF4). These results reaffirm the potential role of MSA as a chemopreventive agent via the regulation of KLF4/miR-200a/Keap1/Nrf2 axis in ESCC cells.     

miR-19通过Keap-Nrf2/HO-1信号通路对卵巢癌细胞增殖的影响

摘要 目的：研究卵巢癌组织和细胞中miR-19的表达,探讨其异常表达对卵巢癌细胞Kelch样环氧氯丙烷相关蛋白-1（Kelch-like epichlorohydrin-associated protein1,Keap1）--核因子E2相关因子2（nuclearfactor-E2-relatedfactor2,Nrf2） /血红素氧合酶-1（heme oxygenase1,HO-1）信号通路及卵巢癌细胞增殖的影响。方法：回顾性收集2019年1月至2020年12月于我院就诊的患者经病理切片诊断为卵巢癌上皮细胞的手术标本30例,卵巢良性肿瘤标本30例,正常卵巢组织标本30例。免疫组化检测不同标本中Keap1、Nrf2、HO-1的表达,检测卵巢组织及细胞中miR-19、Keap1、Nrf2、HO-1的mRNA表达水平,及卵巢癌细胞中Keap1、Nrf2、HO-1的蛋白表达水平。在OVCAR-3细胞中沉默miR-19后,Western Blot检测细胞内Keap1、Nrf2、HO-1蛋白表达水平,收集沉默miR-19,对照组,沉默Nrf2、对照组的OVCAR-3细胞,继续培养0 h、24 h、48 h后,检测细胞增殖和凋亡。结果：Keap1蛋白在卵巢癌组织中的阳性表达显著低于良性卵巢肿瘤组织及正常卵巢组织;Nrf2和HO-1蛋白在卵巢癌组织中的阳性表达显著低于良性卵巢肿瘤组织及正常卵巢组织（P＜0.05）;沉默miR-19抑制其表达后,细胞内Keap1 mRNA、蛋白表达水平明显升高,Nrf2、HO-1 mRNA表达水平无明显变化,蛋白表达水平明显降低（P＜0.05）;沉默miR-19 组、沉默Nrf2组与转染阴性对照组相比,增殖能力明显降低,凋亡能力明显升高（P＜0.05）。结论：卵巢癌细胞中,miR-19表达水平升高,可通过调控Keap1-Nrf2/HO-1信号通路影响卵巢癌细胞的增值、凋亡能力。