Department of Radiation Oncology, Klinikum rechts der Isar, Technische Universität München, and Clinical Cooperation Group (CCG) 'Innate Immunity in Tumor Biology', Helmholtz Zentrum München, German Research Center for Environmental Health (HMGU), Munich, Germany.
J Cell Mol Med. 2011 Apr;15(4):874-87. doi: 10.1111/j.1582-4934.2010.01067.x.
The major stress-inducible heat shock protein 70 (Hsp70) is frequently present on the cell surface of human tumours, but not on normal cells. Herein, the binding characteristics of the cmHsp70.1 mouse monoclonal antibody (mAb) were evaluated in vitro and in a syngeneic tumour mouse model. More than 50% of the CT26 mouse colon carcinoma cells express Hsp70 on their cell surface at 4°C. After a temperature shift to 37°C, the cmHsp70.1-fluorescein isothiocyanate mAb translocates into early endosomes and lysosomes. Intraoperative and near-infrared fluorescence imaging revealed an enrichment of Cy5.5-conjugated mAb cmHsp70.1, but not an identically labelled IgG1 isotype-matched control, in i.p. and s.c. located CT26 tumours, as soon as 30 min. after i.v. injection into the tail vein. Due to the rapid turnover rate of membrane-bound Hsp70, the fluorescence-labelled cmHsp70.1 mAb became endocytosed and accumulated in the tumour, reaching a maximum after 24 hrs and remained detectable at least up to 96 hrs after a single i.v. injection. The tumour-selective internalization of mAb cmHsp70.1 at the physiological temperature of 37°C might enable a targeted uptake of toxins or radionuclides into Hsp70 membrane-positive tumours. The anti-tumoral activity of the cmHsp70.1 mAb is further supported by its capacity to mediate antibody-dependent cytotoxicity.
主要的应激诱导热休克蛋白 70（Hsp70）经常存在于人类肿瘤的细胞表面，但不存在于正常细胞中。在此，评估了 cmHsp70.1 小鼠单克隆抗体（mAb）在体外和同种肿瘤小鼠模型中的结合特性。在 4°C 时，超过 50%的 CT26 小鼠结肠癌细胞在其细胞表面表达 Hsp70。温度升高到 37°C 后，cmHsp70.1-异硫氰酸荧光素 mAb 易位到早期内体和溶酶体。术中近红外荧光成像显示，Cy5.5 标记的 mAb cmHsp70.1 在腹腔和皮下定位的 CT26 肿瘤中富集，但同种型匹配的 IgG1 对照标记的则没有，在尾静脉注射后 30 分钟即可观察到。由于膜结合 Hsp70 的快速周转率，荧光标记的 cmHsp70.1 mAb 被内吞并在肿瘤中积累，在 24 小时后达到最大值，并在单次静脉注射后至少 96 小时内仍可检测到。mAb cmHsp70.1 在生理温度 37°C 下的肿瘤选择性内化可能使毒素或放射性核素靶向进入 Hsp70 阳性膜肿瘤。cmHsp70.1 mAb 的抗肿瘤活性还得到了其介导抗体依赖性细胞毒性的能力的支持。
