Venkataraman Srimathi, Li Yi-Chuan, Hung Zi-Wei, Hsu Yu-Chieh, Yang Zhuo, Tsai Tsung-I, Hung Mien-Chie, Han Kyung Ho, Lin Chih-Wei
Graduate Institute of Biological Science and Technology, China Medical University Taichung 406040, Taiwan.
Department of Biological Science and Technology, China Medical University Taichung 406040, Taiwan.
Am J Cancer Res. 2025 May 15;15(5):2127-2139. doi: 10.62347/DJMA8500. eCollection 2025.
G protein-coupled receptors (GPCRs) play important roles by transmitting signals when they bind to specific ligands in human. Dysregulation of the GPCRs has been associated to metabolic diseases, inflammatory and cancers, and making them key targets for therapeutic intervention. The structural characterization of GPCR-ligand interactions remains challenging due to the difficulty in obtaining complex structures. In this study, we chose CXC chemokine receptor 4 (CXCR4), a member of the GPCR family, as the receptor and employed AlphaFold3 to predict the interaction sites between ligands and GPCRs. The results show that the extracellular loop 2 (ECL2) region is crucial for CXCL12-CXCR4 interactions. Using this epitope-guided approach, we selected antibodies from a combinatorial library that bind to CXCR4 and block CXCL12 signaling. Two antibodies, C5 and F4, were found to inhibit CXCL12 signaling in reporter cell lines. Furthermore, these antibodies also exhibited antibody-dependent cellular cytotoxicity against the acute T cell leukemia cell line and the B cell lymphoma cell line. This approach provides a promising way to develop effective antibodies for treating CXCR4-expressed cancer cells, as well as for other diseases linked to GPCR dysfunction.
G蛋白偶联受体（GPCRs）在人体内与特定配体结合时通过传递信号发挥重要作用。GPCRs的失调与代谢性疾病、炎症和癌症有关，使其成为治疗干预的关键靶点。由于难以获得复合物结构，GPCR-配体相互作用的结构表征仍然具有挑战性。在本研究中，我们选择了GPCR家族成员CXC趋化因子受体4（CXCR4）作为受体，并采用AlphaFold3预测配体与GPCRs之间的相互作用位点。结果表明，细胞外环2（ECL2）区域对于CXCL12-CXCR4相互作用至关重要。使用这种表位引导方法，我们从组合文库中筛选出与CXCR4结合并阻断CXCL12信号传导的抗体。发现两种抗体C5和F4可抑制报告细胞系中的CXCL12信号传导。此外，这些抗体还对急性T细胞白血病细胞系和B细胞淋巴瘤细胞系表现出抗体依赖性细胞毒性。这种方法为开发用于治疗表达CXCR4的癌细胞以及与GPCR功能障碍相关的其他疾病的有效抗体提供了一种有前景的途径。
