Hu Yi, Qiao Chunxia, Lv Ming, Feng Jiannan, Yu Ming, Shen Beifen, Zhang Qiuping, Li Yan
Department of Immunology, School of Basic Medical ScienÎ, Wuhan University, Wuhan, 430071, China.
BMC Res Notes. 2012 Jul 2;5:336. doi: 10.1186/1756-0500-5-336.
HER2 plays a critical role in the pathogenesis of many cancers and is linked to poor prognosis or cancer metastases. Monoclonal antibodies, such as Herceptin against HER2-overexpressing cancers, have showed satisfactory clinical therapeutic effect. However, they have difficulty to surmount obstacles to enter cells or blood-brain barrier.
In this study, a cell-penetrating peptide Arg9 was linked to the C-terminus of anti-HER2 single chain antibody (MIL5scFv). Flow cytometry, confocal microscopy and electron microscopy analysis all revealed that Arg9 peptide facilitated the penetration of MIL5scFv into HER2-negative cell line NIH3T3 and orientate in mitochondria. More interestingly, Western blot assay showed the potential enhanced bioactivity of MIL5scFv-Arg9 in HER2+ cell line SKOV3, indicating that Arg9 could help large molecules (e.g. antibody) to penetrate into cells and therefore enhance its anti-neoplastic function.
Our work represented an attractive by preliminary strategy to enhance the therapeutic effect of existing antibodies by entering cells easier, or more desirable, surmounting the physical barriers, especially in hard-to-reach cancers such as brain metastases cases.
HER2在多种癌症的发病机制中起关键作用，与预后不良或癌症转移相关。单克隆抗体，如针对HER2过表达癌症的赫赛汀，已显示出令人满意的临床治疗效果。然而，它们难以克服进入细胞或血脑屏障的障碍。
在本研究中，一种细胞穿透肽Arg9与抗HER2单链抗体（MIL5scFv）的C末端相连。流式细胞术、共聚焦显微镜和电子显微镜分析均显示，Arg9肽促进了MIL5scFv进入HER2阴性细胞系NIH3T3并定位于线粒体。更有趣的是，蛋白质印迹分析表明MIL5scFv-Arg9在HER2+细胞系SKOV3中具有潜在增强的生物活性，表明Arg9可帮助大分子（如抗体）进入细胞，从而增强其抗肿瘤功能。
我们的工作代表了一种有吸引力的初步策略，即通过更易进入细胞，或者更理想的是，克服物理屏障，尤其是在难以触及的癌症如脑转移病例中，来增强现有抗体的治疗效果。
