Part 2: Influence of 2-Euryfuryl-1,4-naphthoquinone and Its peri-Hydroxy Derivatives on Both Cell Death and Metabolism of TLT Cells, a Murine Hepatoma Cell Line. Modulation of Cytotoxicity by Vitamin C
作者:Julio Benites、Jaime Adolfo Valderrama、Henryk Taper、Pedro Buc Calderon
DOI:10.1248/cpb.57.615
日期:——
2-Euryfuryl-1,4-naphthoquinone C1 and its 5- and 5,8-hydroxy derivatives C2 and C3, were tested for their cytotoxicity towards transplantable liver tumor (TLT) cells (a murine hepatoma cell line) in the absence and in the presence of vitamin C. Cell death, caspase-3 activity and two metabolic end-points, namely the intracellular content of ATP and glutathione (GSH), were employed to evaluate their cytotoxicity. In a range of concentration from 0 to 10 μg/ml C1 and C3 were non toxic against TLT cells, while compound C2 killed about 50% of cells by necrosis. Interestingly, the presence of vitamin C did not enhance the cytolysis of C2, but its addition exacerbated the effects of the three compounds on both ATP and GSH contents, the two metabolic end points selected in our study. Our assumption is that the electron donor effect of the peri-hydroxyl substituents on euryfurylnaphthoquinones and the hydrogen bond between the peri-hydroxy and quinone carbonyl groups influence the electron-acceptor capability of the quinone nucleus and thus modifies the electron transfer from ascorbate to the electroactive quinone nucleus. The combination of euryfurylnaphthoquinones with vitamin C may be of potential clinical interest, because cancer cells accumulate vitamin C, they are sensitive to an oxidant insult and they depend on glycolysis (ATP formation) for their survival.
在没有维生素 C 和维生素 C 存在的情况下,测试了 2-呋喃基-1,4-萘醌 C1 及其 5- 和 5,8- 羟基衍生物 C2 和 C3 对移植性肝肿瘤(TLT)细胞(一种小鼠肝癌细胞系)的细胞毒性。在 0 至 10 μg/ml 的浓度范围内,C1 和 C3 对 TLT 细胞无毒性,而化合物 C2 则使约 50% 的细胞坏死。有趣的是,维生素 C 的存在并没有增强 C2 的细胞溶解作用,但它的加入却加剧了这三种化合物对 ATP 和 GSH 含量的影响,而 ATP 和 GSH 含量正是我们研究中选定的两个代谢终点。我们的假设是,十二烷基萘醌上围羟基取代基的电子供体效应以及围羟基和醌羰基之间的氢键影响了醌核的电子受体能力,从而改变了抗坏血酸向电活性醌核的电子转移。将十二烷基萘醌与维生素 C 结合使用可能具有潜在的临床意义,因为癌细胞会积聚维生素 C,它们对氧化剂的刺激很敏感,而且它们的生存依赖于糖酵解(ATP 的形成)。