Pirker R, FitzGerald D J, Willingham M C, Pastan I
Laboratory of Molecular Biology, National Cancer Institute, Bethesda, Maryland 20892.
Cancer Res. 1988 Jul 15;48(14):3919-23.
The present study evaluates whether the in vitro activity of immunotoxins can be enhanced by verapamil or by various antagonists of calmodulin (dansylcadaverine, trifluoperazine, chlorpromazine). The following immunotoxins made with either Pseudomonas exotoxin (PE), recombinant ricin A chain (rRTA), or ricin A chain (RTA) were used: HB21-PE and 454A12-rRTA that both recognize the human transferrin receptor; and 260F9-rRTA and 454C11-RTA that both react with human ovarian and breast cancer cells. The cytotoxicity of these immunotoxins was determined in human ovarian carcinoma cell lines and KB cells. Verapamil, that was demonstrated previously to enhance the cell-killing activity of PE immunotoxins, enhanced the activity of several ricin A chain immunotoxins, including 454A12-rRTA, 260F9-rRTA, and 454C11-RTA. Comparing 50% inhibitory dose values for inhibition of protein synthesis by 454A12-rRTA, enhancement ranged from 2- to greater than 25-fold, was dependent on the concentration of verapamil, and was greatest at short incubation times. In addition, the cytotoxicity of HB21-PE and of selected RTA immunotoxins was increased up to 30-fold by the addition of various calmodulin antagonists. The enhancing drugs did not decrease the specificity of the immunotoxins.
本研究评估维拉帕米或各种钙调蛋白拮抗剂（丹磺酰尸胺、三氟拉嗪、氯丙嗪）是否能增强免疫毒素的体外活性。使用了以下用铜绿假单胞菌外毒素（PE）、重组蓖麻毒素A链（rRTA）或蓖麻毒素A链（RTA）制备的免疫毒素：均识别人类转铁蛋白受体的HB21-PE和454A12-rRTA；以及均与人卵巢癌细胞和乳腺癌细胞反应的260F9-rRTA和454C11-RTA。在人卵巢癌细胞系和KB细胞中测定了这些免疫毒素的细胞毒性。先前已证明能增强PE免疫毒素细胞杀伤活性的维拉帕米，增强了几种蓖麻毒素A链免疫毒素的活性，包括454A12-rRTA、260F9-rRTA和454C11-RTA。比较454A12-rRTA抑制蛋白质合成的50%抑制剂量值，增强范围为2至大于25倍，取决于维拉帕米的浓度，且在短孵育时间时最大。此外，添加各种钙调蛋白拮抗剂后，HB21-PE和选定的RTA免疫毒素的细胞毒性增加了30倍。增强药物并未降低免疫毒素的特异性。
