Selection and Characterization of FD164, a High-Affinity Signal Regulatory Protein alpha Variant with Balanced Safety and Effectiveness, from a Targeted Epitope Mammalian Cell-Displayed Antibody Library
Selection and Characterization of FD164, a High-Affinity Signal Regulatory Protein alpha Variant with Balanced Safety and Effectiveness, from a Targeted Epitope Mammalian Cell-Displayed Antibody Library
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从靶向表位哺乳动物细胞展示抗体库中选择和表征 FD164，一种具有平衡安全性和有效性的高亲和力信号调节蛋白 α 变体
DOI：
10.1124/molpharm.120.000202
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发表时间：
2021
影响因子：
3.6
通讯作者：
Luo Longlong
中科院分区：
文献类型：
--
作者：
Wang Zhihong;Hu Naijing;Li Xinying;Wang Haitao;Ren Caiping;Qiao Chunxia;Chen Guojiang;Wang Jing;Zhou Liuzhong;Wu Jiaguo;Zhang Dingmu;Feng Jiannan;Shen Beifen;Peng Hui;Luo Longlong
吞噬抵抗在肿瘤介导的免疫逃逸中起关键作用，因此吞噬免疫检查点是肿瘤免疫治疗的潜在靶点。CD47是重要的吞噬免疫检查点之一，阻断CD47与信号调节蛋白α（SIRPα）的相互作用可能为肿瘤治疗提供新的选择。利用计算机辅助的靶向表位哺乳动物细胞展示抗体库，我们筛选并获得了一个工程化的SIRPα可变片段可结晶融合蛋白FD164，其与CD47的结合活性高于野生型SIRPα。与野生型SIRPα相比，FD164与CD47的结合亲和力约高3倍，这进一步增强了其体外吞噬作用和体内肿瘤抑制活性。FD 164在小鼠异种移植模型中保持了与临床研究药物Hu5F9相似的抗肿瘤活性。此外，FD164联合利妥昔单抗可显著提高单药治疗的效果。另一方面，与Hu5F9相比，FD 164不引起血细胞凝集，并且在相同浓度下其与红细胞或白色细胞结合的能力较弱。最后，通过计算机结构预测和丙氨酸扫描实验证实了CD47的N45、E47、52TEVYVK58、K60、115EVTELTRE122和E124残基对SIRPα或FD164的识别是重要的。简而言之，我们获得了具有平衡的安全性和有效性的高亲和力SIRPα变体FD164。到目前为止，临床上市的靶向CD47的药物很少被确定为有效和安全的。FD164是一种潜在的信号调节蛋白α变体片段可结晶蛋白，具有安全性和有效性的平衡，可为抗肿瘤药物的开发提供参考。
Phagocytic resistance plays a key role in tumor-mediated immune escape, so phagocytosis immune checkpoints are a potential target for cancer immunotherapy. CD47 is one of the important phagocytosis immune checkpoints; thus, blocking the interaction between CD47 and signal regulatory protein α (SIRPα) may provide new options for cancer treatment. Using computer-aided targeted epitope mammalian cell-displayed antibody library, we screened and obtained an engineered SIRPα variant fragment crystallizable fusion protein, FD164, with higher CD47-binding activity than wild-type SIRPα. Compared with wild-type SIRPα, FD164 has approximately 3-fold higher affinity for binding to CD47, which further enhanced its phagocytic effect in vitro and tumor suppressor activity in vivo. FD164 maintains the similar antitumor activity of the clinical research drug Hu5F9 in the mouse xenograft model. Furthermore, FD164 combined with rituximab can significantly improve the effect of single-agent therapy. On the other hand, compared with Hu5F9, FD164 does not cause hemagglutination, and its ability to bind to red blood cells or white blood cells is weaker at the same concentration. Finally, it was confirmed by computer structure prediction and alanine scanning experiments that the N45, E47, 52TEVYVK58, K60, 115EVTELTRE122, and E124 residues of CD47 are important for SIRPα or FD164 recognition. Briefly, we obtained a high-affinity SIRPα variant FD164 with balanced safety and effectiveness. SIGNIFICANCE STATEMENT Up to now, few clinically marketed drugs targeting CD47 have been determined to be effective and safe. FD164, a potential signal regulatory protein α variant fragment crystallizable protein with balanced safety and effectiveness, could provide a reference for the development of antitumor drugs.