Zaja Roko, Popović Marta, Lončar Jovica, Smital Tvrtko
Laboratory for Molecular Ecotoxicology, Division for Marine and Environmental Research, Ruđer Bošković Institute, Zagreb, Croatia.
Laboratory for Molecular Ecotoxicology, Division for Marine and Environmental Research, Ruđer Bošković Institute, Zagreb, Croatia.
Comp Biochem Physiol C Toxicol Pharmacol. 2016 Dec;190:15-23. doi: 10.1016/j.cbpc.2016.07.005. Epub 2016 Jul 27.
ABCG2 (BCRP - breast cancer resistance protein) belongs to the ATP-binding cassette (ABC) superfamily. It plays an important role in the disposition and elimination of xeno- and endobiotics and/or their metabolites in mammals. Likewise, the protective role of ABC transporters, including Abcg2, has been reported for aquatic organisms. In our previous study we have cloned the full gene sequence of rainbow trout (Oncorhynchus mykiss) Abcg2a and showed its high expression in liver and primary hepatocytes. Based on those insights, the main goal of this study was to perform a detailed functional characterization of trout Abcg2a using insect ovary cells (Spodoptera frugiperda, Sf9) as a heterologous expression system. Membrane vesicles preparations from Sf9 cells were used for the ATPase assay determinations and basic biochemical properties of fish Abcg2a versus human ABCG2 have been compared. A series of 39 physiologically and/or environmentally relevant substances was then tested on interaction with trout Abcg2a and human ABCG2. Correlation analysis reveals highly similar pattern of activation and inhibition. Significant activation of trout Abcg2a ATPase was observed for prazosin, doxorubicine, sildenafil, furosemid, propranolol, fenofibrate and pheophorbide. Pesticides showed either a weak activation (malathione) or strong (endosulfan) to weak (chlorpyrifos, fenoxycarb, DDE) inhibition of trout Abcg2a ATPase while the highest activation was obtained for benzo(a)pyrene, curcumine and testosterone. In conclusion, data from this study offer the first characterization of fish Abcg2a, reveal potent interactors among physiologically or environmentally relevant substances and point to similarities regarding strengths and interactor preferences between human ABCG2 and fish Abcg2a.
ABCG2（乳腺癌耐药蛋白，BCRP）属于ATP结合盒（ABC）超家族。它在哺乳动物对外源生物和内源性生物及其代谢产物的处置和消除过程中发挥着重要作用。同样，包括Abcg2在内的ABC转运蛋白对水生生物的保护作用也已有报道。在我们之前的研究中，我们克隆了虹鳟（Oncorhynchus mykiss）Abcg2a的完整基因序列，并表明其在肝脏和原代肝细胞中高表达。基于这些认识，本研究的主要目标是利用昆虫卵巢细胞（草地贪夜蛾，Sf9）作为异源表达系统，对虹鳟Abcg2a进行详细的功能表征。来自Sf9细胞的膜囊泡制剂用于ATP酶活性测定，并比较了鱼类Abcg2a与人ABCG2的基本生化特性。然后测试了一系列39种生理和/或环境相关物质与虹鳟Abcg2a和人ABCG2的相互作用。相关性分析揭示了高度相似的激活和抑制模式。观察到哌唑嗪、阿霉素、西地那非、速尿、普萘洛尔、非诺贝特和脱镁叶绿酸对虹鳟Abcg2a ATP酶有显著激活作用。农药对虹鳟Abcg2a ATP酶表现出弱激活（马拉硫磷）或强抑制（硫丹）至弱抑制（毒死蜱、苯氧威、滴滴涕），而苯并（a）芘、姜黄素和睾酮的激活作用最强。总之，本研究的数据首次对鱼类Abcg2a进行了表征，揭示了生理或环境相关物质之间的有效相互作用因子，并指出了人ABCG2和鱼类Abcg2a在强度和相互作用因子偏好方面的相似性。
