Dai Qinsheng, Yin Qian, Wei Libin, Zhou Yuxin, Qiao Chen, Guo Yongjian, Wang Xiaotang, Ma Shiping, Lu Na
State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Carcinogenesis and Intervention, Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, China Pharmaceutical University, Nanjing, P.R. China.
Department of Chemistry and Biochemistry, Florida International University, Miami, Florida.
Mol Carcinog. 2016 Aug;55(8):1275-89. doi: 10.1002/mc.22369. Epub 2015 Aug 10.
Metabolic alteration in cancer cells is one of the most conspicuous characteristics that distinguish cancer cells from normal cells. In this study, we investigated the influence and signaling ways of oroxylin A affecting cancer cell energy metabolism under hypoxia. The data showed that oroxylin A remarkably reduced the generation of lactate and glucose uptake under hypoxia in HepG2 cells. Moreover, oroxylin A inhibited HIF-1α expression and its stability. The downstream targets (PDK1, LDHA, and HK II), as well as their mRNA levels were also suppressed by oroxylin A under hypoxia. The silencing or the overexpression of HIF-1α assays suggested that HIF-1α is required for metabolic effect of oroxylin A in HepG2 cells during hypoxia. Furthermore, oroxylin A could reduce the expression of complex III in mitochondrial respiratory chain, and then decrease the accumulation of ROS at moderate concentrations (0-50 µM) under hypoxia, which was benefit for its inhibition on glycolytic activity by decreasing ROS-mediated HIF-1 expression. Besides, oroxylin A didn't cause the loss of MMP under hypoxia and had no obvious effects on the expression of OXPHOS complexes, suggesting that oroxylin A did not affect mitochondrial mass at the moderate stress of oroxylin A. The suppressive effect of oroxylin A on glycolysis led to a significantly repress of ATP generation, for ATP generation mostly depends on glycolysis in HepG2 cells. This study revealed a new aspect of glucose metabolism regulation of oroxylin A under hypoxia, which may contribute to its new anticancer mechanism. © 2015 Wiley Periodicals, Inc.
癌细胞中的代谢改变是区分癌细胞与正常细胞的最显著特征之一。在本研究中,我们调查了木犀草素A在缺氧条件下对癌细胞能量代谢的影响及其信号传导途径。数据显示,木犀草素A在缺氧条件下显著降低了HepG2细胞中乳酸的生成和葡萄糖摄取。此外,木犀草素A抑制HIF-1α的表达及其稳定性。在缺氧条件下,木犀草素A还抑制了下游靶点(PDK1、LDHA和HK II)及其mRNA水平。HIF-1α的沉默或过表达实验表明,在缺氧期间,HepG2细胞中木犀草素A的代谢作用需要HIF-1α。此外,木犀草素A可降低线粒体呼吸链中复合物III的表达,进而在缺氧条件下以中等浓度(0-50µM)减少ROS的积累,这有利于其通过降低ROS介导的HIF-1表达来抑制糖酵解活性。此外,木犀草素A在缺氧条件下不会导致线粒体膜电位丧失,对氧化磷酸化复合物的表达也无明显影响,这表明在木犀草素A的中等应激条件下,它不会影响线粒体质量。木犀草素A对糖酵解的抑制作用导致ATP生成显著减少,因为在HepG2细胞中ATP生成主要依赖于糖酵解。本研究揭示了木犀草素A在缺氧条件下葡萄糖代谢调节的一个新方面,这可能有助于其新的抗癌机制。©2015威利期刊公司