靶向毒素DT-VEGF的构建、表达与活性分析

肿瘤的快速生长依赖于新生血管的形成。血管内皮生长因子（VEGF）是血管发生和形成过程中的主要介质，其特异性受体在正常组织和肿瘤组织的表达率存在数个数量级的差异，因此可以将毒素分子转运至增生的肿瘤上皮组织中抑制肿瘤血管增生，从而抑制肿瘤的生长。将白喉毒素的前389个氨基酸基因片段与VEGF165通过一短肽相连构建为融合蛋白基因，在大肠杆菌中表达，获得纯化蛋白。实验证实该融合蛋白对血管内皮细胞有特异性杀伤作用，并研究了其对鸡胚尿囊膜新生血管的抑制作用。

Construction, Expression and Bioactivity Characterization of Targeting Toxin DT-VEGF

Tumor rapid growth depends on neovascularization. Vascular endothelial growth factor, the main mediator during the occurrence and formation of vascularization, has specific receptors whose expression rate shows difference of orders of magnitude between tumor and the normal tissue, so it can be used to transport toxin molecules to the proliferative tumor endothelial and kill cancer cells. In our experiment, we constructed fusion protein DT-VEGF by linking diphtheria toxin's forward 389 amino acids's gene and VEGF165 via a linker. DT-VEGF is expressed in E. coli and purified. Our experiment proves in can kill vascular endothelial cells specifically, and the inhibition of neovascularization of chicken chorionic membrane is also confirmed.