Lyso-GM3, its dimer, and multimer: their synthesis, and their effect on epidermal growth factor-induced receptor tyrosine kinase
Lyso-GM3, its dimer, and multimer: their synthesis, and their effect on epidermal growth factor-induced receptor tyrosine kinase
复制标题
DOI：
10.1007/s10719-007-9051-2
复制
发表时间：
2007-07
影响因子：
3
通讯作者：
Yoshimi Murozuka;Naoko Watanabe;K. Hatanaka;S. Hakomori
中科院分区：
文献类型：
--
作者：
Yoshimi Murozuka;Naoko Watanabe;K. Hatanaka;S. Hakomori
已知鞘糖脂，特别是神经节苷脂，调节生长因子受体酪氨酸激酶。一个有据可查的例子是GM 3对人表皮样癌A431细胞中与表皮生长因子受体（EGFR）相关的激酶的抑制作用。Lyso-GM 3在A431细胞中被检测为次要组分，并且可能在GM 3依赖性抑制EGFR中起辅助因子的作用。我们研究了化学合成的GM 3、lyso-GM 3及其衍生物对EGFR功能的抑制作用，基于它们在膜微区中的相互作用，主要发现：（1）GM 3、EGFR和小窝蛋白共存，但四跨膜蛋白CD 9和CD 82基本上不存在，在同一低密度膜组分中，通过蔗糖密度梯度超离心分离。(2)EGFR与GM 3之间的强相互作用通过EGFR与GM 3包被的聚苯乙烯珠的结合以GM 3剂量依赖性方式增加来指示。共聚焦显微镜的结果表明，在微域中的三个组件（GM 3，EGFR和小窝蛋白）是密切相关的。(3)Lyso-GM 3或lyso-GM 3二聚体以剂量依赖性方式强烈抑制EGFR激酶活性，而lyso-GM 3三聚体和四聚体则没有。>50 μM的lyso-GM 3具有细胞溶解性，而>50 μM的lyso-GM 3二聚体不具有细胞溶解性，但强烈抑制EGFR激酶。因此，lyso-GM 3及其二聚体对GM 3诱导的EGFR激酶抑制和细胞生长具有辅助作用，lyso-GM 3二聚体可能是表皮肿瘤生长的药物抑制剂的良好候选物。
Glycosphingolipids, particularly gangliosides, are known to modulate growth factor receptor tyrosine kinase. A well-documented example is the inhibitory effect of GM3 on kinase associated with epidermal growth factor receptor (EGFR) in human epidermoid carcinoma A431 cells. Lyso-GM3 was detected as a minor component in A431 cells, and may function as an auxiliary factor in GM3-dependent inhibition of EGFR. We studied the inhibitory effect of chemically synthesized GM3, lyso-GM3, and its derivatives, on EGFR function, based on their interaction in membrane microdomain, with the following major findings: (1) GM3, EGFR, and caveolin coexist, but tetraspanins CD9 and CD82 are essentially absent, within the same low-density membrane fraction, separated by sucrose density gradient ultracentrifugation. (2) Strong interaction between EGFR and GM3 was indicated by increasing binding of EGFR to GM3-coated polystyrene beads, in a GM3 dose-dependent manner. Confocal microscopy results suggested that three components in the microdomain (GM3, EGFR, and caveolin) are closely associated. (3) Lyso-GM3 or lyso-GM3 dimer strongly inhibited EGFR kinase activity, in a dose-dependent manner, while lyso-GM3 trimer and tetramer did not. >50 μM lyso-GM3 was cytolytic, while >50 μM lyso-GM3 dimer was not cytolytic, yet inhibited EGFR kinase strongly. Thus, lyso-GM3 and its dimer exert an auxiliary effect on GM3-induced inhibition of EGFR kinase and cell growth, and lyso-GM3 dimer may be a good candidate for pharmacological inhibitor of epidermal tumor growth.