Targeted tumor therapy by epidermal growth factor appended toxin and purified saponin: An evaluation of toxicity and therapeutic potential in syngeneic tumor bearing mice
Targeted tumor therapy by epidermal growth factor appended toxin and purified saponin: An evaluation of toxicity and therapeutic potential in syngeneic tumor bearing mice
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DOI：
10.1016/j.molonc.2012.12.004
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发表时间：
2013-06-01
影响因子：
6.6
通讯作者：
Fuchs, Hendrik
中科院分区：
文献类型：
--
作者：
Thakur, Mayank;Mergel, Katharina;Fuchs, Hendrik
靶向的基于毒素的治疗剂受到细胞内摄取差、稳定性有限和非特异性免疫刺激的阻碍。为了解决这些问题，配体靶向毒素与低剂量皂苷混合物的组合在过去已经被调整并在体内测试，然而，未定义的皂苷原始混合物不适合用于临床开发。因此，在本工作中，我们使用了靶向毒素（Sap 3-EGF，即与表皮生长因子融合的皂草素）与结构上确定的分离的皂草素m/z 1861（SO-1861）组合。体外评价证实了Sap 3-EGF对TSA-EGFR靶细胞的细胞毒性功效增强6900倍。靶毒素的所需剂量明显减少，并且观察到高度协同效应。离体溶血试验显示，SO-1861浓度高达10 μ g/mL时无溶血或溶血极少。在急性毒性研究中，发现SO-1861在高达100 μ g/治疗剂量下无毒性。酶天冬氨酸转氨酶、丙氨酸转氨酶和谷氨酸脱氢酶未显示任何统计学显著性肝损伤，这通过组织学检查进一步证实。此外，肌酐也与对照组相似，因此排除了肾脏损伤。通过每次治疗应用30 μ g SO-1861和0.1 μ g Sap 3-EGF，在以EGFR过表达为特征的同基因BALB/c肿瘤模型中进行体内研究。减少90%以上（p
Targeted toxin-based therapeutics are hindered by poor intracellular uptake, limited stability and non-specific immune stimulation. To address these problems, ligand-targeted toxins in combination with low dose saponin mixtures have been adapted and tested in vivo in the past, however, undefined saponin raw mixtures are not suitable for use in clinical development. In the present work we therefore used a targeted toxin (Sap3-EGF, i.e. saporin fused to epidermal growth factor) in combination with a structurally defined isolated saponin m/z 1861 (SO-1861). In vitro evaluation confirmed a 6900-fold enhancement in the cytotoxic efficacy of Sap3-EGF against TSA-EGFR target cells. The required dose of the targeted toxin was appreciably reduced and there was a highly synergistic effect observed. An ex vivo hemolysis assay showed no or very less hemolysis up to 10 mu g/mL of SO-1861. In the acute toxicity studies SO-1861 was found to be non-toxic up to a dose of 100 mu g/treatment. The enzymes aspartate aminotransferase, alanine aminotransferase, and glutamate dehydrogenase did not show any statistically significant liver damage, which was further confirmed by histological examination. Additionally, creatinine was also similar to the control group thus ruling out damage to kidney. In vivo studies in a syngeneic BALB/c tumor model characterized by EGFR overexpression were done by applying 30 mu g SO-1861 and 0.1 mu g Sap3-EGF per treatment. A more than 90% reduction (p