Abstract

Epidermal growth factor receptor (EGFR) and vascular endothelial growth factor receptor (VEGFR) represent two clinically validated targets for a variety of human cancers, and dual inhibition of EGFR and VEGF(R) has demonstrated superior activity to single EGFR inhibitors. This study was to construct a novel bispecific decoy receptor VEGFR-EGFR/Fc that contains Fc portion of human IgG1 acted as molecular scaffold, and the immunoglobulin-like domain 1–3 of VEGFR1 and extracellular domain of EGFR fused to the N-terminal and C-terminal of Fc, respectively, aiming at capturing the EGF-like ligands and VEGF. ELISA showed that VEGFR-EGFR/Fc bound to EGF, TGF-α and VEGF with high affinity. It displayed potent proliferation inhibitory effects on human non-small-cell lung cancer A549 cells and human umbilical vein endothelial cells revealed by MTT assays. VEGFR-EGFR/Fc significantly inhibited cell invasion and migration demonstrated by wound healing assay and transwell assay. In vivo, VEGFR-EGFR/Fc showed remarkable growth inhibition on A549 xenografts. Cell apoptosis and inhibition of angiogenesis were also observed in xenograft tumour tissues. Mechanistically, VEGFR-EGFR/Fc pre-treatment blocked the phosphorylation of EGFR and VEGFR2 and resulted in a decrease in the downstream signalling molecules, AKT, p44/42MAPK and p38MAPK. These data suggest VEGFR-EGFR/Fc would be a promising candidate for cancer targeted therapy.

摘要

表皮生长因子受体 (EGFR) 和血管内皮生长因子受体 (VEGFR) 代表了两种经过临床验证的针对多种人类癌症的靶点，EGFR 和 VEGF(R) 的双重抑制已显示出优于单一 EGFR 抑制剂的活性。本研究旨在构建一种新型双特异性诱饵受体 VEGFR-EGFR/Fc，其含有人 IgG1 的 Fc 部分作为分子支架，VEGFR1 的免疫球蛋白样结构域 1-3 和 EGFR 的胞外结构域融合到 N 端和分别位于 Fc 的 C 端，旨在捕获 EGF 样配体和 VEGF。ELISA显示VEGFR-EGFR/Fc与EGF、TGF-α和VEGF以高亲和力结合。通过 MTT 测定显示，它对人非小细胞肺癌 A549 细胞和人脐静脉内皮细胞具有有效的增殖抑制作用。在体内，VEGFR-EGFR/Fc 对 A549 异种移植物表现出显着的生长抑制作用。在异种移植肿瘤组织中也观察到细胞凋亡和血管生成抑制。从机制上讲，VEGFR-EGFR/Fc 预处理阻断了 EGFR 和 VEGFR2 的磷酸化，并导致下游信号分子 AKT、p44/42MAPK 和 p38MAPK 减少。这些数据表明 VEGFR-EGFR/Fc 将是癌症靶向治疗的有希望的候选者。