NG2 proteoglycan-binding peptides target tumor neovasculature.
NG2 proteoglycan-binding peptides target tumor neovasculature.
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发表时间：
1999-06
期刊：
影响因子：
11.2
通讯作者：
Michael A. Burg;Renata Pasqualini;W. Arap;E. Ruoslahti;W. Stallcup
中科院分区：
文献类型：
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作者：
Michael A. Burg;Renata Pasqualini;W. Arap;E. Ruoslahti;W. Stallcup
NG 2是人黑色素瘤蛋白聚糖的大鼠同源物，也称为高分子量黑色素瘤相关抗原。这种发育调节的跨膜硫酸软骨素蛋白聚糖主要由神经胶质细胞、肌肉和软骨祖细胞表达。成熟后，这些细胞类型下调NG 2表达。在成年动物中，NG 2的表达仅限于肿瘤细胞和血管生成性肿瘤血管系统，使得这种蛋白聚糖成为将治疗剂导向相关作用部位的潜在靶标。为此，我们已经确定了特定的NG 2结合肽筛选噬菌体展示的随机肽库纯化NG 2。在NG 2上进行几轮生物淘选导致两个噬菌体展示的十肽TAASGVRSMH和LTLRWVGLMS的特异性富集。通过可溶性NG 2和含有同源肽序列的谷胱甘肽S-转移酶（GST）融合蛋白，这些GST与NG 2的结合是可重复的。此外，GST-TAASGVRSMH和GST-LTLRWVGLMS融合蛋白与NG 2之间的直接结合在固相结合测定中得到证实。有趣的是，这些NG 2结合融合蛋白交叉抑制彼此与NG 2的结合，表明这两个序列结合到蛋白聚糖上的相同或重叠位点。在注射到荷瘤小鼠中后，NG 2-结合的GFP特异性地归巢到野生型小鼠中的肿瘤脉管系统，但不定位到NG 2敲除小鼠中的肿瘤脉管系统。这些序列的体内靶向能力表明它们可用于肿瘤靶向。
NG2 is the rat homologue of the human melanoma proteoglycan, also known as the high molecular weight melanoma-associated antigen. This developmentally regulated membrane-spanning chondroitin sulfate proteoglycan is expressed primarily by glial, muscle, and cartilage progenitor cells. Upon maturation, these cell types down-regulate NG2 expression. In adult animals, the expression of NG2 is restricted to tumor cells and angiogenic tumor vasculature, making this proteoglycan a potential target for directing therapeutic agents to relevant sites of action. To this end, we have identified specific NG2-binding peptides by screening a phage-displayed random peptide library on purified NG2. Several rounds of biopanning on NG2 resulted in the specific enrichment of two phage-displayed decapeptides, TAASGVRSMH and LTLRWVGLMS. The binding of these phages to NG2 was inhibitable both by soluble NG2 and by glutathione S-transferase (GST) fusion proteins containing the cognate peptide sequences. In addition, direct binding between GST-TAASGVRSMH and GST-LTLRWVGLMS fusion proteins and NG2 was demonstrated in solid-phase binding assays. Interestingly, these NG2-binding fusion proteins cross-inhibited each other's binding to NG2, suggesting that the two sequences bind to the same or overlapping sites on the proteoglycan. Upon injection into tumor-bearing mice, NG2-binding phages specifically homed to tumor vasculature in wild-type mice but did not localize to the tumor vasculature in NG2 knockout mice. The in vivo targeting capability of these sequences suggests that they can be used for tumor targeting.