A hyperfusogenic gibbon ape leukemia envelope glycoprotein: Targeting of a cytotoxic gene by ligand display
A hyperfusogenic gibbon ape leukemia envelope glycoprotein: Targeting of a cytotoxic gene by ligand display
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DOI：
10.1089/10430340050015437
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发表时间：
2000-04-10
影响因子：
4.2
通讯作者：
Russell, SJ
中科院分区：
文献类型：
--
作者：
Fielding, AK;Chapel-Fernandes, S;Russell, SJ
肿瘤基因治疗的一个重要目标是开发新的靶向细胞毒基因。观察到将缺乏R肽的GalV包膜糖蛋白导入人细胞可导致大量的细胞-细胞融合和随后的细胞死亡，这促使我们探索将这种融合膜糖蛋白(EMG)用作靶向细胞毒基因的可能性。因此，作为原理的证明，我们在Galv囊膜糖蛋白的N端显示了表皮生长因子(EGF)，并且有或没有R肽(Galv R+和Galv R-)，转染GaLVR+包膜表达载体不能引起细胞-细胞融合，将Galv R+包膜导入逆转录病毒载体，研究其对EGF受体阳性和阴性细胞的感染性。含有N端未修饰包膜的载体能够感染所有测试的人类细胞系。该载体的感染性仅限于EGF受体阳性细胞(而不是EGF受体阴性细胞)，并可通过显示结构域的蛋白酶切割或与外源配体竞争而恢复。通过质粒DNA转染检测了N端未修饰且同时显示EGF和胰岛素样生长因子I[IGF-II]的Galv R-包膜糖蛋白的细胞-细胞融合能力，而N端未修饰的Galv R-融合所有受试的人细胞类型，显示EGF或IGF-I的Galv R-在受体阳性细胞上的融合性受到很大限制。“对等”竞争实验表明，只有与相应的外源配体竞争才能恢复融合性，因此，生长因子配体的N-端展示可以调节超抗原Galv包膜糖蛋白的细胞-细胞融合的特异性。因此，通过使用与我们为靶向逆转录病毒载体开发的策略类似的策略，进一步开发这种融合病毒糖蛋白的细胞杀伤能力的靶向具有重要的潜力。
An important goal in cancer gene therapy is the development of novel targeted cytotoxic genes. The observation that transfection of a GaLV envelope glycoprotein lacking an R peptide into human cells results in considerable cell-cell fusion and subsequent cell death prompted us to explore the potential for using this fusogenic membrane glycoprotein (EMG) as a targeted cytotoxic gene. As proof of principle, we therefore displayed epidermal growth factor (EGF) on the N terminus of GaLV envelope glycoproteins both with and without an R peptide (GaLV R+ and GaLV R-), Transfection of the GaLVR+ envelope expression plasmids did not cause cell-cell fusion, The GaLV R+ envelopes were incorporated into retroviral vectors whose infectivity was investigated on EGF receptor-positive and -negative cells. The vector incorporating an N-terminally unmodified envelope was able to infect all human cell lines tested. Infectivity of the vector incorporating an envelope on which EGF was displayed was restricted on EGF receptor-positive cells (but not on EGF receptor-negative cells) and could be restored by protease cleavage of the displayed domain or competition with exogenous ligand, The cell-cell fusion capacity of the GaLV R- envelope glycoproteins (N-terminally unmodified and with N-terminal display of both EGF and insulin-like growth factor I [IGF-II) was investigated by plasmid DNA transfection, While the N-terminally unmodified GaLV R- fused all human cell types tested, fusogenicity of GaLV R- on which EGF or IGF-I was displayed was considerably restricted on receptor-positive cells. "Reciprocal" competition experiments showed that fusogenicity could be restored by competition only with the relevant exogenous ligand, Thus the specificity of cell-cell fusion by a hyperfusogenic GaLV envelope glycoprotein can be regulated by N-terminal display of growth factor ligands. There is therefore significant potential for further development of the targeting of the cell-killing capability of this fusogenic viral glycoprotein by using strategies similar to those we have developed for the targeting of retroviral vectors.