Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore, Singapore.
PLoS One. 2012;7(2):e31196. doi: 10.1371/journal.pone.0031196. Epub 2012 Feb 16.
Vascular endothelial growth factor (VEGF(165)) is a potent angiogenic mitogen commonly overexpressed in cancerous cells. It contains two main binding domains, the receptor-binding domain (RBD) and the heparin-binding domain (HBD). This study attempted to identify the specific sequences of the VEa5 DNA aptamer that exhibit high binding affinity towards the VEGF(165) protein by truncating the original VEa5 aptamer into different segments. Using surface plasmon resonance (SPR) spectroscopy for binding affinity analysis, one of the truncated aptamers showed a >200-fold increase in the binding affinity for HBD. This truncated aptamer also exhibited high specificity to HBD with negligible binding affinity for VEGF(121), an isoform of VEGF lacking HBD. Exposing colorectal cancer cells to the truncated aptamer sequence further confirmed the binding affinity and specificity of the aptamer to the target VEGF(165) protein. Hence, our approach of aptamer truncation can potentially be useful in identifying high affinity aptamer sequences for the biological molecules and targeting them as antagonist for cancer cell detection.
血管内皮生长因子（VEGF(165)）是一种在癌细胞中过度表达的强有力的血管生成有丝分裂原。它包含两个主要的结合域，受体结合域（RBD）和肝素结合域（HBD）。本研究试图通过截短原始 VEa5 适体来鉴定对 VEGF(165) 蛋白表现出高结合亲和力的 VEa5 DNA 适体的特定序列。通过表面等离子体共振（SPR）光谱法进行结合亲和力分析，一种截短的适体对 HBD 的结合亲和力增加了>200 倍。该截短的适体对 HBD 具有高度特异性，对缺乏 HBD 的 VEGF 同种型（VEGF(121)）的结合亲和力可忽略不计。将结直肠癌细胞暴露于截短的适体序列进一步证实了适体与靶标 VEGF(165)蛋白的结合亲和力和特异性。因此，我们的适体截短方法可能有助于鉴定生物分子的高亲和力适体序列，并将其作为针对癌细胞检测的拮抗剂。
