Salimi Fatemeh, Forouzandeh Moghadam Mehdi, Rajabibazl Masoumeh
Department of Medical Biotechnology, Faculty of Medical Sciences, Tarbiat Modares University, Nasr Bridge, P.O. Box 14115-331, Tehran, Iran.
Department of Clinical Biochemistry, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Mol Biol Rep. 2018 Dec;45(6):2247-2256. doi: 10.1007/s11033-018-4386-2. Epub 2018 Sep 17.
HER2 is a member of epidermal factor receptor (EGFR) family which is overexpressed in breast cancer, ovarian cancer and gastric cancer. Development of new binders for cancer cell surface receptors and expressing them at the surface of exosomes would be a great approach in targeted cancer therapy. We found a high affinity scFv against HER2 using ribosome display with the approach of applying it as a targeting moiety at the surface of exosomes by fusion to lysosomal associated membrane protein 2B (LAMP2B). We also provide some structural information about the ribosome display selected scFv (scFv HFS2) through modeling the 3D structure of scFv HFS2 using RosettaAntibody and docked it at the extracellular domain of HER2. We also evaluated the structure of scFv HFS2 and its binding to HER2 after fusion to LAMP2B. Our results showed no significant change in 3D structure of scFv HFS2 when fused to LAMP2B (RMSD 1.3) and interaction analysis represented that scFv HFS2 binds HER2 domain III before and after fusion to LAMP2B. Although binding domain of scFv HFS2 on HER2 was the same at both state, residues involved in their interactions showed significant differences as it was probably due to the spatial hindrance of scFv HFS2 when fused to LAMP2B through a short linker and it should be considered before proceeding to experiment.
HER2是表皮生长因子受体（EGFR）家族的成员，在乳腺癌、卵巢癌和胃癌中过表达。开发针对癌细胞表面受体的新型结合物并将其在外泌体表面表达，将是靶向癌症治疗的一种很好的方法。我们通过核糖体展示技术找到了一种针对HER2的高亲和力单链抗体片段（scFv），并采用将其与溶酶体相关膜蛋白2B（LAMP2B）融合的方法，将其作为外泌体表面的靶向部分。我们还通过使用RosettaAntibody对scFv HFS2的三维结构进行建模，提供了一些关于核糖体展示筛选出的scFv（scFv HFS2）的结构信息，并将其对接至HER2的细胞外结构域。我们还评估了scFv HFS2与LAMP2B融合后的结构及其与HER2的结合情况。我们的结果表明，scFv HFS2与LAMP2B融合后其三维结构没有显著变化（均方根偏差为1.3），相互作用分析表明，scFv HFS2在与LAMP2B融合前后均与HER2结构域III结合。虽然scFv HFS2在HER2上的结合结构域在两种状态下是相同的，但参与相互作用的残基显示出显著差异，这可能是由于scFv HFS2通过短连接子与LAMP2B融合时的空间位阻所致，在进行实验之前应予以考虑。
