Aluri Suhaas Rayudu, Shi Pu, Gustafson Joshua A, Wang Wan, Lin Yi-An, Cui Honggang, Liu Shuanglong, Conti Peter S, Li Zibo, Hu Peisheng, Epstein Alan L, MacKay John Andrew
Department of Pharmacology and Pharmaceutical Sciences, University of Southern California , Los Angeles, California 90033, United States.
ACS Nano. 2014 Mar 25;8(3):2064-76. doi: 10.1021/nn403973g. Epub 2014 Feb 14.
B-cell lymphomas continue to occur with a high incidence. The chimeric antibody known as Rituximab (Rituxan) has become a vital therapy for these patients. Rituximab induces cell death via binding and clustering of the CD20 receptor by Fcγ expressing effector cells. Because of the limited mobility of effector cells, it may be advantageous to cluster CD20 directly using multivalent nanostructures. To explore this strategy, this manuscript introduces a nanoparticle that assembles from a fusion between a single chain antibody and a soluble protein polymer. These hybrid proteins express in Escherichia coli and do not require bioconjugation between the antibody and a substrate. Surprisingly a fusion between an anti-CD20 single chain antibody and a soluble protein polymer assemble worm-like nanostructures, which were characterized using light scattering and cryogenic transmission electron microscopy. These nanoworms competitively bind CD20 on two B-cell lymphoma cell lines, exhibit concentration-dependent induction of apoptosis, and induce apoptosis better than Rituximab alone. Similar activity was observed in vivo using a non-Hodgkin lymphoma xenograft model. In comparison to Rituximab, systemic nanoworms significantly slowed tumor growth. These findings suggest that hybrid nanoworms targeted at CD20 may be useful treatments for B-cell related malignancies. Because of the ubiquity of antibody therapeutics, related nanoworms may have uses against other molecular targets.
B细胞淋巴瘤的发病率持续居高不下。名为利妥昔单抗（美罗华）的嵌合抗体已成为这些患者的重要治疗手段。利妥昔单抗通过表达Fcγ的效应细胞与CD20受体结合并聚集，从而诱导细胞死亡。由于效应细胞的移动性有限，直接使用多价纳米结构聚集CD20可能具有优势。为了探索这一策略，本文介绍了一种由单链抗体与可溶性蛋白质聚合物融合而成的纳米颗粒。这些杂合蛋白在大肠杆菌中表达，无需抗体与底物之间进行生物偶联。令人惊讶的是，抗CD20单链抗体与可溶性蛋白质聚合物的融合形成了蠕虫状纳米结构，利用光散射和低温透射电子显微镜对其进行了表征。这些纳米蠕虫竞争性地结合两种B细胞淋巴瘤细胞系上的CD20，呈现出浓度依赖性的凋亡诱导作用，且诱导凋亡的效果优于单独使用利妥昔单抗。在非霍奇金淋巴瘤异种移植模型中，体内实验也观察到了类似的活性。与利妥昔单抗相比，全身性纳米蠕虫显著减缓了肿瘤生长。这些发现表明，靶向CD20的杂合纳米蠕虫可能是治疗B细胞相关恶性肿瘤的有效方法。由于抗体治疗药物的广泛应用，相关纳米蠕虫可能对其他分子靶点也有治疗作用。
