Department Pathology & Cell Biology, College of Medicine, University of South Florida, Tampa FL, USA.
Cancer Cell Int. 2011 Aug 12;11:27. doi: 10.1186/1475-2867-11-27.
Chlorotoxin (TM601), a scorpion venom- derived 36-AA peptide, is an experimental drug against recurrent glioma with tumor specificity but unknown route of intracellular distribution. The aim of this study was to evaluate the route of entry and cellular localization of TM601 in glioma cells.
We have found that in human gliomas, lung carcinoma and normal vascular endothelial cells, TM601 localizes near trans-Golgi while in normal human dermal fibroblasts (NHDF) and astrocytes it is dispersed in the cytoplasm. The uptake of TM601 by U373 glioma cells is rapid, concentration and time dependent, not affected by inhibitors such as filipin (caveolae-dependent endocytosis) and amiloride (non-selective macropinocytosis), but significantly affected by chlorpromazine (clathrin-dependent intracellular transport of coated pits) resulting in intracellular build-up of the drug and clathrin near the Golgi. In contrast, TM601 uptake by NHDF cells was significantly affected by amiloride indicating that macropinocytosis is the dominant uptake route of TM601 in these cells.
In conclusion, we found a distinct cellular localization pattern and uptake of TM601 by glioma cells differing from that found in normal cells. Further insight into the cellular processing of TM601 should assist in the development of effective anti-glioma therapeutic modalities.
Chlorotoxin（TM601），一种源自蝎子毒液的 36 个氨基酸肽，是一种针对复发性神经胶质瘤的实验药物，具有肿瘤特异性，但细胞内分布途径未知。本研究旨在评估 TM601 在神经胶质瘤细胞中的进入途径和细胞内定位。
我们发现，在人神经胶质瘤、肺癌和正常血管内皮细胞中，TM601 定位于反式高尔基体附近，而在正常的人真皮成纤维细胞（NHDF）和星形胶质细胞中，TM601 则分散在细胞质中。U373 神经胶质瘤细胞对 TM601 的摄取是快速的、浓度和时间依赖性的，不受 Filipin（小窝依赖性胞吞作用）和阿米洛利（非选择性巨胞饮作用）等抑制剂的影响，但明显受氯丙嗪（网格蛋白依赖性有被小泡的细胞内运输）的影响，导致细胞内药物和网格蛋白在高尔基体附近积聚。相比之下，NHDF 细胞对 TM601 的摄取明显受到阿米洛利的影响，表明巨胞饮作用是 TM601 在这些细胞中的主要摄取途径。
总之，我们发现神经胶质瘤细胞对 TM601 的摄取具有明显不同的细胞内定位模式，与正常细胞不同。进一步深入了解 TM601 的细胞内处理过程，应该有助于开发有效的抗神经胶质瘤治疗方法。
