中文摘要
Galectin-1 (Gal-1)，屬於動物lactins家族的一員。由兩個具有ㄧ段可與β-半乳糖結合的胺基酸序列之次單位(subunits)以非共價鍵的方式鍵結組成的同型二聚體(homodimer)，其分子量14 kDa共有135個胺基酸。Galectin-1蛋白涵括了許多生物上的功能，例如:細胞貼附、細胞增生、移動、細胞凋亡、發炎反應、轉移以及免疫調節等。本研究我們利用immunohistochemistry 發現galectin-1高度表現於口腔癌檢體之腫瘤周圍血管內皮細胞。同時發現口腔癌細胞株的conditioned medium可刺激血管內皮細胞(HUVECs)表現較多的Galectin-1。我們進一步的去釐清galectin-1在內皮細胞及誘發腫瘤血管新生成中所扮演的角色。In vitro，galectin-1有效地促進內皮細胞的貼附及移動；In vivo，galectin-1具有誘發血管通透性的能力。而Galectin-1造成的細胞貼附及移動現象在經由galectin-1抗體作用後，發現幾乎完全被抑制，高濃度的乳糖只有部分地抑制細胞貼附但可有效抑制Galectin-1誘導的細胞移動。另外，我們以表面薄膜共振系統又稱Biacore 系統之分析，發現neuropilin-1(NRP-1)具有結合galectin-1的能力，NRP1濃度增加對galectin-1結合的量也增加，其解離常數(KD)約為10-8M.；利用流式細胞儀分析FITC-galectin-1對細胞表面的結合能力，發現knockdown內皮細胞中的NRP-1，有效地降低了FITC-galectin-1對血管內皮細胞之結合。而且 galectin-1促進內皮細胞的貼附及移動也可以被NRP-1抗體或knockdown NRP1等方式抑制。此外，根據先前學者研究指出，NRP-1會去調控內皮細胞對細胞外基質(extracellular matrix)的貼附。而我們發現外加galectin-1具有增加內皮細胞對細胞外基質的貼附力，而且knockdown galectin-1會抑制內皮細胞對細胞外基質的貼附力，另外內皮細胞貼附於galectin-1的能力也會因knockdown NRP-1而減低。綜上所述，galectin-1過度表現於腫瘤周圍的血管內皮細胞，galectin-1透過結合在血管內皮細胞上的neuropilin-1而影響血管內皮細胞活性進而調控腫瘤血管的新生。

英文摘要
Galectin-1 (Gal-1) is a 14-kDa β-galactoside-binding lectin and involves in multiple biological functions, such as cell adhesion, cell proliferation, migration, apoptosis, inflammation, metastasis and immunoregulation. In the present study, we found that galectin-1 was highly expressed in tumor associated vascular endothelial cells in oral cancer specimens by immunohistochemical staining. The expression of galectin-1 in human umbilical vein endothelial cells (HUVECs) was upregulated by oral cancer cells conditioned media. We further clarified the functional role of galectin-1 in HUVECs and tumor induced neovascularization. Galectin-1 effectively promoted endothelial cells adhesion and migration in vitro, and increased vascular permeability in vivo. The galectin-1 induced HUVECs migration activities could be almost completely inhibited by antibodies of galectin-1 and high concentration of lactose, but the galectin-1-induced HUVECs adhesion was blocked only partially by high concentration of lactose. By surface plasmon resonance analysis, we found that galectin-1 could bind to neuropilin-1 (NRP-1) in a dose dependent manner and its dissociation constant (KD) was also determined to be around 10-8 M. Flow cytometry analysis showed that the binding of FITC-conjugated galectin-1 to HUVECs was inhibited by knockdown of NRP-1 expression. Furthermore, the biological effects of galectin-1 on HUVECs could be suppressed by anti-NRP-1 antibodies and silencing of NRP-1. Besides, previous report has shown that NRP-1 regulates attachment in human endothelial cells and is a critical regulator of endothelial cell adhesion to extracellular matrix. We found that HUVECs adhered to extracellular matrix could be enhanced by exogenous galectin-1 and inhibited by knockdown of galectin-1 expression. Endothelial cells adhered to galectin-1 could also be inhibited by silencing of NRP-1. Taken together, overexpression of galectin-1 in cancer associated endothelial cells might play important roles on tumor angiogenesis through interaction with NRP-1.

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