Targeting endothelial cells overexpressing VEGFR-2: Selective toxicity of Shiga-like toxin-VEGF fusion proteins
Targeting endothelial cells overexpressing VEGFR-2: Selective toxicity of Shiga-like toxin-VEGF fusion proteins
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DOI：
10.1021/bc015534j
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发表时间：
2001-11-01
影响因子：
4.7
通讯作者：
Backer, JM
中科院分区：
文献类型：
--
作者：
Backer, MV;Backer, JM
在血管生成部位生长的内皮细胞表达大量VEGF受体，因此可能对VEGF介导的药物递送特别敏感。为了验证这一假设，我们构建了一种蛋白质，其含有与VEGF（121）融合的志贺样毒素I的催化A亚基（SLT-VEGF/L）。野生型A亚基是28 S rRNA的位点特异性N-糖苷酶，其在通过单独的细胞结合B亚基递送到细胞中后抑制蛋白质合成。SLT-VEGF/L保留了VEGF 121和VEGF 121部分的功能活性，因为它抑制无细胞翻译系统中的蛋白质合成并诱导VEGFR-2酪氨酸自磷酸化。SLT-VEGF/L选择性抑制表达2.5 x 10（5）VEGFR-2/细胞的猪内皮细胞的生长，IC 50为0.2 nM，并在浓度> 1 nM时快速诱导细胞凋亡。我们发现，转染VEGFR-2的PAE细胞对SLT-VEGF/L的敏感性随着细胞内VEGFR-2密度的降低而降低;表达25000个VEGFR-2/细胞的PAE细胞与缺乏受体的亲本细胞一样敏感。SLT-VEGF/L的生长抑制和凋亡诱导需要内源性的N-糖苷酶活性，但不会显著抑制蛋白质合成。SLT-VEGF/L对过表达VEGFR-2的生长内皮细胞的选择性细胞毒性表明，它可能有助于靶向血管生成部位的类似细胞。
Growing endothelial cells at the sites of angiogenesis express high numbers of VEGF receptors and therefore may be particularly sensitive to VEGF-mediated drug delivery. To test this hypothesis we have constructed a protein containing the catalytic A-subunit of Shiga-like toxin I fused to VEGF(121) (SLT-VEGF/L). Wild-type A-subunit is a site-specific N-glycosidase of 28S rRNA that inhibits protein synthesis after being delivered into cells by separate cell-binding B-subunits. SLT-VEGF/L retains functional activities of both SLT and VEGF121 moieties, since it inhibits protein synthesis in a cell-free translation system and induces VEGFR-2 tyrosine autophosphorylation. SLT-VEGF/L selectively inhibits growth of porcine endothelial cells expressing 2.5 x 10(5) VEGFR-2/cell with an IC50 of 0.2 nM and rapidly induces apoptosis at concentrations > 1 nM. We found that sensitivity of VEGFR-2 transfected PAE cells to SLT-VEGF/L declined as the cellular VEGFR-2 density decreased; PAE cells expressing 25000 VEGFR-2/cell were as, sensitive as parental cells lacking the receptor. Growth inhibition and induction of apoptosis by SLT-VEGF/L require intrinsic N-glycosidase activity of the SLT moiety, but take place without significant inhibition of protein synthesis. Selective cytotoxicity of SLT-VEGF/L against growing endothelial cells overexpressing VEGFR-2 suggests that it may be useful in targeting similar cells at the sites of angiogenesis.