Interleukin 13 mutants of enhanced avidity toward the glioma-associated receptor, IL13Rα2
Interleukin 13 mutants of enhanced avidity toward the glioma-associated receptor, IL13Rα2
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DOI：
10.1016/s1476-5586(04)80049-6
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发表时间：
2004-01-01
期刊：
影响因子：
4.8
通讯作者：
Debinski, W
中科院分区：
文献类型：
--
作者：
Madhankumar, AB;Mintz, A;Debinski, W
白细胞介素13（IL 13）结合在恶性神经胶质瘤中高度过表达的受体IL 13 Ra 2。IL 13蛋白由四个螺旋组成：α-螺旋A、B、C和D，并且我们在α-螺旋D中发现了一个新的“热点”，其对于IL 13与IL 13 Ra 2的结合至关重要。Lys-105加上Lys-106和Arg-109代表该热点。在本研究中，我们在IL 13的这三个位置进行了取代。我们检测了基于IL 13的细胞毒素的胶质瘤细胞杀伤中和和新IL 13突变体的直接受体结合。我们观察到，实际上，Lys-105和Arg-109对于IL 13与IL 13 Ra 2的结合是关键的。然而，在肿瘤靶向方面鉴定了具有重要性质的新突变体。其中赖氨酸被精氨酸取代的IL13.K105R突变体比野生型IL 13更有效地中和基于IL 13的细胞毒素对IL 13 Ra 2阳性细胞的杀伤。然而，IL13.K105L或IL13.K105A被剥夺了任何此类活性。此外，当与野生型IL 13相比时，IL13.K105R和IL13.R109K与[I-125] IL 13结合至IL 13 Ra 2结合位点的竞争分别好77倍和27倍。因此，我们已经发现了对IL 13 Ra 2具有更高亲合力的IL 13的第一种形式。这些突变体应证明在抗癌诊断/治疗的进一步设计中是有用的。
Interleukin 13 (IL13) binds a receptor that is highly overexpressed in malignant gliomas, IL13Ralpha2. IL13 protein is composed of four helices: alpha-helix A, B, C, and D, and we found a new "hot spot" in alpha-helix D that is crucial for the binding of IL13 to IL13Ralpha2. Lys-105 plus Lys-106 and Arg-109 represent this hot spot. In the current study, we have made substitutions at these three positions in IL13. We examined both neutralization of an IL13-based cytotoxin's glioma cell killing and direct receptor binding of the new IL13 mutants. We observed that Lys-105 and Arg-109 are critical for IL13 binding to IL13Ralpha2, indeed. However, new mutants of important properties were identified with regard to tumor targeting. IL13.K105R mutant, in which lysine was substituted by arginine, neutralized the killing of IL13Ralpha2-positive cells by IL13-based cytotoxin more efficiently than wild-type IL13. However, IL13.K105L or IL13.K105A was deprived of any such activity. Furthermore, IL13.K105R and IL13.R109K competed 77- and 27-fold better, respectively, with the binding of [I-125]IL13 to the IL13Ra2 binding sites when compared with wild-type IL13. Thus, we have uncovered the first forms of IL13 of higher avidity toward IL13Ralpha2. These mutants should prove useful in the further design of anticancer diagnostics/therapeutics.