Specific targeting to murine myeloma cells of Cyt1Aa toxin from Bacillus thuringiensis subspecies israelensis
Specific targeting to murine myeloma cells of Cyt1Aa toxin from Bacillus thuringiensis subspecies israelensis
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DOI：
10.1074/jbc.m703567200
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发表时间：
2007-09-28
影响因子：
4.8
通讯作者：
Firer, Michael A.
中科院分区：
文献类型：
--
作者：
Cohen, Shmuel;Cahan, Rivka;Firer, Michael A.
多发性骨髓瘤目前是一种无法治愈的浆B细胞癌症，其特征通常是异常大量的患者特异性克隆型免疫球蛋白“M-蛋白”的过度产生。“M蛋白在细胞膜上表达并分泌到血液中。我们以前表明，配体-毒素缀合物（LTC）纳入核糖体失活蓖麻毒素-A是非常有效的抗配体抗体携带的靶细胞作为多发性骨髓瘤模型的特异性细胞溶解。在这里，我们报告的膜破坏Cyt 1Aa毒素从苏云金芽孢杆菌亚种。Israelensis转化为靶向鼠骨髓瘤细胞的LTC。蛋白水解活化的Cyt 1Aa通过其氨基或羧基末端与髓鞘碱性蛋白的主要肽表位VHFFKNIVTPRTP（p87-99）化学或遗传缀合。将重组融合基因克隆到无晶体细胞B中进行表达。苏云金通过穿梭载体pHT 315将其转化到israelensis中。化学结合和基因融合的LTC对表达抗髓鞘碱性蛋白的鼠杂交瘤细胞都有毒性，但重组结合物更有活性。包含Cyt 1Aa毒素的LTC可能是有用的抗癌剂。作为一种膜作用毒素，Cyt 1Aa不太可能诱导抗性细胞系的发展。
Multiple myeloma is currently an incurable cancer of plasma B cells often characterized by overproduction of abnormally high quantities of a patient-specific, clonotypic immunoglobulin "M-protein." The M-protein is expressed on the cell membrane and secreted into the blood. We previously showed that ligand-toxin conjugates (LTC) incorporating the ribosome-inactivating Ricin-A toxin were very effective in specific cytolysis of the anti-ligand antibody-bearing target cells used as models for multiple myeloma. Here, we report on the incorporation of the membrane-disruptive Cyt1Aa toxin from Bacillus thuringiensis subsp. israelensis into LTCs targeted to murine myeloma cells. Proteolytically activated Cyt1Aa was conjugated chemically or genetically through either its amino or carboxyl termini to the major peptidic epitope VHFFKNIVTPRTP (p87-99) of the myelin basic protein. The recombinant fusion-encoding genes were cloned and expressed in acrystalliferous B. thuringiensis subsp. israelensis through the shuttle vector pHT315. Both chemically conjugated and genetically fused LTCs were toxic to anti-myelin basic protein-expressing murine hybridoma cells, but the recombinant conjugates were more active. LTCs comprising the Cyt1Aa toxin might be useful anticancer agents. As a membrane-acting toxin, Cyt1Aa is not likely to induce development of resistant cell lines.