Heukers Raimond, Mashayekhi Vida, Ramirez-Escudero Mercedes, de Haard Hans, Verrips Theo C, van Bergen En Henegouwen Paul M P, Oliveira Sabrina
QVQ Holding BV, Yalelaan 1, 3584 CL Utrecht, The Netherlands.
Cell Biology Division, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
Antibodies (Basel). 2019 Apr 4;8(2):26. doi: 10.3390/antib8020026.
Photodynamic therapy (PDT) is an approach that kills (cancer) cells by the local production of toxic reactive oxygen species upon the local illumination of a photosensitizer (PS). The specificity of PDT has been further enhanced by the development of a new water-soluble PS and by the specific delivery of PS via conjugation to tumor-targeting antibodies. To improve tissue penetration and shorten photosensitivity, we have recently introduced nanobodies, also known as VHH (variable domains from the heavy chain of llama heavy chain antibodies), for targeted PDT of cancer cells overexpressing the epidermal growth factor receptor (EGFR). Overexpression and activation of another cancer-related receptor, the hepatocyte growth factor receptor (HGFR, c-Met or Met) is also involved in the progression and metastasis of a large variety of malignancies. In this study we evaluate whether anti-Met VHHs conjugated to PS can also serve as a biopharmaceutical for targeted PDT. VHHs targeting the SEMA (semaphorin-like) subdomain of Met were provided with a C-terminal tag that allowed both straightforward purification from yeast supernatant and directional conjugation to the PS IRDye700DX using maleimide chemistry. The generated anti-Met VHH-PS showed nanomolar binding affinity and, upon illumination, specifically killed MKN45 cells with nanomolar potency. This study shows that Met can also serve as a membrane target for targeted PDT.
光动力疗法(PDT)是一种通过在局部照射光敏剂(PS)时局部产生活性氧来杀死(癌症)细胞的方法。新型水溶性PS的开发以及通过与肿瘤靶向抗体偶联实现PS的特异性递送,进一步提高了PDT的特异性。为了改善组织穿透性并缩短光敏期,我们最近引入了纳米抗体,也称为VHH(羊驼重链抗体重链可变区),用于对过表达表皮生长因子受体(EGFR)的癌细胞进行靶向PDT。另一种癌症相关受体,即肝细胞生长因子受体(HGFR,c-Met或Met)的过表达和激活也参与了多种恶性肿瘤的进展和转移。在本研究中,我们评估与PS偶联的抗Met VHH是否也可作为靶向PDT的生物药物。靶向Met的SEMA(类信号素)亚结构域的VHH带有一个C端标签,这使得既能直接从酵母上清液中纯化,又能使用马来酰亚胺化学方法将其与PS IRDye700DX定向偶联。生成的抗Met VHH-PS显示出纳摩尔级的结合亲和力,并且在光照下能以纳摩尔效力特异性杀死MKN45细胞。这项研究表明,Met也可作为靶向PDT的膜靶点。