Globotriaosylceramide-Expressing Burkitt's Lymphoma Cells Are Committed to Early Apoptotic Status by Rhamnose-Binding Lectin from Catfish Eggs
Globotriaosylceramide-Expressing Burkitt's Lymphoma Cells Are Committed to Early Apoptotic Status by Rhamnose-Binding Lectin from Catfish Eggs
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DOI：
10.1248/bpb.32.345
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发表时间：
2009-03-01
影响因子：
2
通讯作者：
Nitta, Kazuo
中科院分区：
文献类型：
--
作者：
Kawano, Tasuku;Sugawara, Shigeki;Nitta, Kazuo
南方鳕卵凝集素(SAL)不仅对糖蛋白有很强的亲和力，而且对Gb3等神经鞘糖脂也有很强的亲和力。SAL均匀结合于表达Gb3(+)的Burkitt淋巴瘤细胞表面，而Gb3分子散布于Gb3(+)细胞表面。用SAL处理Raji和Daudi细胞一段时间后，细胞大小分别比未处理细胞小10%和25%。SAL可诱导Gb3(+)细胞膜联蛋白V结合增强，但作用22h后未见caspase激活和DNA断裂，提示SAL不能诱导Gb3(+)细胞死亡，可能是早期凋亡信号的诱导者。我们发现SAL不能与D-threo-1-phenyl-2-decanoylamino-3-morphorino-1-propanol(D-PDMP)处理的Raji细胞结合，并且SAL处理的Gb3缺陷型Raji细胞没有观察到细胞收缩，这表明Gb3通过激活电压门控性钾通道Kv1.3参与了SAL诱导的细胞收缩，而SAL处理的Go缺陷型Raji细胞上的糖蛋白配体不包括在这种现象中。这些结果表明，SAL通过与GEM中存在的Gb3结合，使细胞处于早期凋亡状态，这种结合是诱导早期细胞凋亡的先决条件。
Silurus asotus(catfish) egg lectin (SAL) has a strong affinity to Gal alpha-linked carbohydrate chains of not only glycoproteins but also glycosphingolipids such as globotriaosylceramide (Gb3). SAL uniformly bound to surfaces of Gb3-expressing (Gb3(+)) Burkitt's lymphoma cells, while Gb3 molecules were interspersed on the surfaces of Gb3(+) cells. After a short period of treating Raji and Daudi cells with SAL, each cell size was 10 and 25% smaller than that of untreated cells, respectively. Treatment of Gb3(+) cells With SAL caused an increase in binding of annexin V, however, neither caspase activation nor DNA fragmentation was observed after treatment with SAL for 22 h. Since SAL did not induce cell death in Gb3(+) cells, SAL may function as an inducer of early apoptotic signal. We have revealed that SAL did not bind to D-threo-1-phenyl-2-decanoylamino-3-morphorino-1-propanol (D-PDMP)-treated Raji cells, and no cell shrinkage was observed in Gb3-deficient Raji cells treated with SAL, Indicating that Gb3 localized in the glycosphingolipid-enriched microdomain (GEM) was involved in SAL-induced cell shrinkage through activation of voltage-gated potassium channel Kv1.3, and that the glycoprotein ligands on GO-deficient Raji cells treated with SAL were not included in this phenomenon. These results suggest that SAL leads the cells to early apoptotic status via binding to Gb3 existing in GEM, and that this binding is a prerequisite condition to induce early stage of apoptosis.