Pan Jianru, He Huocong, Su Ying, Zheng Guangjin, Wu Junxin, Liu Shutao, Rao Pingfan
College of Biological Science and Engineering, Fuzhou University, No. 2 Xue Yuan Road, University Town, Fuzhou, Fujian 350108, China.
Laboratory of Radiation Oncology and Radiobiology, Fujian Provincial Cancer Hospital, Teaching Hospital of Fujian Medical University, Fujian Key Laboratory of Tumor Translational Cancer Medicine, The National Clinical Key Specialty Construction Program of China, No. 420 Fuma Road, Fuzhou 350014, China.
Oxid Med Cell Longev. 2016;2016:5935080. doi: 10.1155/2016/5935080. Epub 2016 May 30.
Superoxide dismutase (SOD) fusion of TAT was proved to be radioprotective in our previous work. On that basis, a bifunctional recombinant protein which was the fusion of glutathione S-transferase (GST), SOD, and TAT was constructed and named GST-TAT-SOD. Herein we report the investigation of the cytotoxicity, cell-penetrating activity, and in vitro radioprotective effect of GST-TAT-SOD compared with wild SOD, single-function recombinant protein SOD-TAT, and amifostine. We demonstrated that wild SOD had little radioprotective effect on irradiated L-02 and Hep G2 cells while amifostine was protective to both cell lines. SOD-TAT or GST-TAT-SOD pretreatment 3 h prior to radiation protects irradiated normal liver cells against radiation damage by eliminating intracellular excrescent superoxide, reducing cellular MDA level, enhancing cellular antioxidant ability and colony formation ability, and reducing apoptosis rate. Compared with SOD-TAT, GST-TAT-SOD was proved to have better protective effect on irradiated normal liver cells and minimal effect on irradiated hepatoma cells. Besides, GST-TAT-SOD was safe for normal cells and effectively transduced into different organs in mice, including the brain. The characteristics of this protein suggest that it may be a potential radioprotective agent in cancer therapy better than amifostine. Fusion of two antioxidant enzymes and cell-penetrating peptides is potentially valuable in the development of radioprotective agent.
在我们之前的工作中，已证明TAT与超氧化物歧化酶（SOD）的融合蛋白具有辐射防护作用。在此基础上，构建了一种双功能重组蛋白，它是谷胱甘肽S-转移酶（GST）、SOD和TAT的融合体，命名为GST-TAT-SOD。本文报告了与野生型SOD、单功能重组蛋白SOD-TAT和氨磷汀相比，GST-TAT-SOD的细胞毒性、细胞穿透活性及体外辐射防护作用的研究。我们发现野生型SOD对受辐照的L-02和Hep G2细胞几乎没有辐射防护作用，而氨磷汀对这两种细胞系均有保护作用。在辐射前3小时用SOD-TAT或GST-TAT-SOD预处理，可通过清除细胞内多余的超氧化物、降低细胞丙二醛水平、增强细胞抗氧化能力和集落形成能力以及降低凋亡率，保护受辐照的正常肝细胞免受辐射损伤。与SOD-TAT相比，GST-TAT-SOD对受辐照的正常肝细胞具有更好的保护作用，而对受辐照的肝癌细胞影响最小。此外，GST-TAT-SOD对正常细胞安全，可有效转导至小鼠的不同器官，包括脑。该蛋白的特性表明，它可能是癌症治疗中比氨磷汀更具潜力的辐射防护剂。两种抗氧化酶与细胞穿透肽的融合在辐射防护剂的开发中可能具有重要价值。
