Immunotoxin-mediated targeting of claudin-4 inhibits the proliferation of cancer cells
Immunotoxin-mediated targeting of claudin-4 inhibits the proliferation of cancer cells
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DOI：
10.3892/ijo.2013.1881
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发表时间：
2013-06-01
影响因子：
5.2
通讯作者：
Wei, M. Q.
中科院分区：
文献类型：
--
作者：
Hashimi, S. M.;Yu, S.;Wei, M. Q.
免疫毒素是一种工程嵌合蛋白，由毒素片段与能够靶向特定细胞的修饰抗体或生长因子融合而成。此外，这些蛋白质可以针对通常在癌细胞上过度表达的受体。大多数免疫毒素通过与细胞结合、移位到胞浆并抑制蛋白质合成来发挥作用。在这项研究中，分析了Claudin-4(CLDN4)在不同癌细胞中的表达，作为免疫毒素的潜在靶点。为了靶向表达CLDN4的癌细胞，将产气荚膜梭菌肠毒素(CPE)的CLDN4结合域与铜绿假单胞菌外毒素A(ETA)结构域融合，形成免疫毒素(CPE-ETA‘)。随后，对这种免疫毒素抑制CLDN4阳性癌细胞增殖的能力进行了研究。我们报告了头颈部鳞状细胞癌细胞(HN5)与其他被测试的细胞系相比，CLDN4的表达水平升高。我们的研究结果进一步表明，CPE-ETA‘对MCF-7乳腺癌细胞[半数抑制浓度(IC50)9.8 ng/ml]和HN5头颈部癌细胞(IC50 8.8 ng/ml)有很强的抑制作用，而对HeLa细胞(CLDN4阴性)没有细胞毒作用。免疫毒素随后在定植于肿瘤的溶瘤菌株Glostridium ghonii中表达。最重要的是，严格厌氧的古氏梭菌能够过度表达和分泌具有功能的CPE-ETA‘融合蛋白。我们的发现开启了使用严格厌氧的高隆梭菌治疗CLDN4阳性癌细胞的局部高浓度定向递送免疫毒素的可能性。
Immunotoxins are engineered chimeric proteins that consist of a fragment of a toxin fused to a modified antibody or growth factor capable of targeting specific cells. Furthermore, these proteins can be targeted to receptors that are commonly overexpressed on cancer cells. The majority of immunotoxins function by binding to cells, translocating into the cytosol and inhibiting protein synthesis. In this study, the expression of claudin-4 (CLDN4) in various cancer cells was analysed as a potential target for immunotoxins. To target CLDN4-expressing cancer cells, the c-terminal CLDN4-binding domain of Clostridium perfringens enterotoxin (CPE) was fused to the Pseudomonas aeruginosa exotoxin A (ETA) domain to create an immunotoxin (CPE-ETA'). Subsequently, the capacity of such an immunotoxin in suppressing the proliferation of CLDN4-positive cancer cells was investigated. We report that head and neck squamous carcinoma cells (HN5) have an elevated CLDN4 expression compared to the other cell lines tested. Our findings further demonstrate that CPE-ETA' is highly potent against MCF-7 breast [50% inhibitory concentration (IC50) 9.8 ng/ml] and HN5 head/neck (IC50 8.8 ng/ml) cancer cell lines, while it has no cytotoxic effects on HeLa cells (CLDN4-negative). The immunotoxin was subsequently expressed in the tumour colonising oncolytic strain, Clostridium ghonii. Most importantly, the strictly anaerobic Clostridium ghonii was able to overexpress and secrete a functional CPE-ETA' fusion protein. Our findings open the possibility of the targeted delivery of the immunotoxin locally to tumour sites at a high concentration using strictly anaerobic Clostridium ghonii for the treatment of CLDN4-positive cancer cells.