Graduate School of Biostudies, Kyoto University, Kyoto, 606-8502, Japan.
Cytotechnology. 2008 Jan;56(1):33-9. doi: 10.1007/s10616-007-9100-5. Epub 2007 Nov 7.
A methanol extract of Alsomitra macrocarpa leaves and branches induced a marked alteration of cell morphology in a human stellate cell line (LX-2). Similar morphologic alterations were observed in several other cell lines. Active compound was purified from the extract and determined to be cucurbitacin E (Cuc E). It has been known that Cuc E causes marked disruption of the actin cytoskeleton, supporting our observation, but how Cuc E altered the actin cytoskeleton has not been elucidated. By using the standard fluorescence assay using copolymerization and depolymerization of native and pyrene labelled actin, this study revealed that Cuc E interacted directly with actin consequently stabilizing the polymerized actin. When NIH-3T3 cells exogenously expressing YFP-labeled actin were treated with Cuc E, firstly the aggregation of globular actin and secondly the aggregation of actin including disrupted fibrous actin in the cells was observed.
Alsomitra macrocarpa 叶和枝的甲醇提取物诱导人星状细胞系 (LX-2) 发生明显的细胞形态改变。在其他几种细胞系中也观察到类似的形态改变。从提取物中分离出活性化合物并确定为葫芦素 E（Cuc E）。已知 Cuc E 会导致肌动蛋白细胞骨架明显破坏，这支持了我们的观察结果，但 Cuc E 如何改变肌动蛋白细胞骨架尚未阐明。通过使用聚合和原生及芘标记肌动蛋白的解聚的标准荧光测定法，本研究表明 Cuc E 直接与肌动蛋白相互作用，从而稳定聚合的肌动蛋白。当用 Cuc E 处理外源表达 YFP 标记肌动蛋白的 NIH-3T3 细胞时，首先观察到球状肌动蛋白的聚集，其次观察到包括细胞中纤维状肌动蛋白破坏的肌动蛋白的聚集。
