Potent and specific antitumor effect of CEA-targeted photoimmunotherapy
Potent and specific antitumor effect of CEA-targeted photoimmunotherapy
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DOI：
10.1002/ijc.28907
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发表时间：
2014-12-01
影响因子：
6.4
通讯作者：
Kuroki, Masahide
中科院分区：
文献类型：
--
作者：
Shirasu, Naoto;Yamada, Hiromi;Kuroki, Masahide
传统的光动力疗法（PDT）的癌症是有限的光敏剂的有效性和特异性不足。我们在此描述了一种高效和选择性的肿瘤靶向PDT，其使用近红外（NIR）光敏剂IRDye 700DX，与癌胚抗原（CEA）特异性的人单克隆抗体（Ab）偶联。这种抗体辅助的PDT（称为光免疫疗法（PIT））的抗肿瘤作用在体外和体内进行了研究。Ab-IRDye缀合物在NIR照射后诱导针对CEA阳性肿瘤细胞的有效细胞毒性，而CEA阴性细胞根本不受影响，即使在过量的光免疫缀合物存在下也是如此。我们发现了一个等效的光毒性和一个主要的质膜定位的抗体IRDye后，一个和六个小时的孵育。无论是没有或很少半胱天冬酶的激活和膜过氧化反应中观察到的PIT处理的细胞和一个面板的活性氧自由基清除剂的光毒性作用只表现出部分抑制。引人注目的是，即使在缺氧条件下，Ab-IRDye也保留了显著的光毒性。我们建立了一个异种移植模型，这使我们能够灵敏地研究PIT的治疗效果的非侵入性生物发光成像。将表达荧光素酶的MKN-45-luc人胃癌细胞皮下植入裸鼠的两侧胁腹。仅对一侧肿瘤进行NIR照射。体内成像和肿瘤大小的测量显示，腹膜内施用Ab-IRDye和随后的NIR照射的单次PIT处理引起快速细胞死亡和肿瘤生长的显著抑制，但仅在照射侧。总之，这些数据表明Ab-IRDye介导的PIT具有作为靶向CEA阳性肿瘤的抗癌治疗剂的巨大潜力。
Conventional photodynamic therapy (PDT) for cancer is limited by the insufficient efficacy and specificity of photosensitizers. We herein describe a highly effective and selective tumor-targeted PDT using a near-infrared (NIR) photosensitizer, IRDye700DX, conjugated to a human monoclonal antibody (Ab) specific for carcinoembryonic antigen (CEA). The antitumor effects of this Ab-assisted PDT, called photoimmunotherapy (PIT), were investigated in vitro and in vivo. The Ab-IRDye conjugate induced potent cytotoxicity against CEA-positive tumor cells after NIR-irradiation, whereas CEA-negative cells were not affected at all, even in the presence of excess photoimmunoconjugate. We found an equivalent phototoxicity and a predominant plasma membrane localization of Ab-IRDye after both one and six hours of incubation. Either no or little caspase activation and membrane peroxidation were observed in PIT-treated cells and a panel of scavengers for reactive oxygen species showed only partial inhibition of the phototoxic effect. Strikingly, Ab-IRDye retained significant phototoxicity even under hypoxia. We established a xenograft model, which allowed us to sensitively investigate the therapeutic efficacy of PIT by noninvasive bioluminescence imaging. Luciferase-expressing MKN-45-luc human gastric carcinoma cells were subcutaneously implanted into both flanks of nude mice. NIR-irradiation was performed for only the tumor on one side. In vivo imaging and measurement of the tumor size revealed that a single PIT treatment, with intraperitoneal administration of Ab-IRDye and subsequent NIR-irradiation, caused rapid cell death and significant inhibition of tumor growth, but only on the irradiated side. Together, these data suggest that Ab-IRDye-mediated PIT has great potential as an anticancer therapeutics targeting CEA-positive tumors.