Cytotoxic activity of gonadotropin-releasing hormone (GnRH)-pokeweed antiviral protein conjugates in cell lines expressing GnRH receptors.
Cytotoxic activity of gonadotropin-releasing hormone (GnRH)-pokeweed antiviral protein conjugates in cell lines expressing GnRH receptors.
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DOI：
10.1210/en.2002-220917
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发表时间：
2003-04
期刊：
影响因子：
4.8
通讯作者：
Wei-Hsiung Yang;Maciej Wieczorck;M. Allen;T. Nett
中科院分区：
文献类型：
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作者：
Wei-Hsiung Yang;Maciej Wieczorck;M. Allen;T. Nett
商陆抗病毒蛋白(PAP)是从商陆叶片中分离得到的一种29 kDa的核糖体失活蛋白，一旦进入细胞质就具有很强的细胞毒活性。它不能自己进入单元格。因此，我们的目标是确定是否可以使用GnRH类似物将PAP特异性地传递到表达GnRH受体的细胞。将D-Lys(6)-GnRH-Pro(9)-乙胺偶联到PAP(GnRH-PAP)上。用稳定表达GnRH受体基因的中国仓鼠卵巢细胞和表达内源性GnRH受体的小鼠促性腺激素肿瘤细胞系(AlphaT3-1细胞)评价GnRH-PAP的细胞毒作用。我们还用人子宫内膜、乳腺和前列腺癌细胞株检测了GnRH-PAP的细胞毒性。GnRH-PAP对GnRH受体阳性细胞具有剂量依赖性的细胞毒作用。GnRH-PAP的细胞毒性依赖于GnRH受体的数量(r(2)=0.871，P<0.05)和作用时间。相反，GnRH-PAP对不含GnRH受体的中国仓鼠卵巢细胞无细胞毒作用。此外，过量的GnRH类似物可抑制GnRH-PAP的细胞毒活性。PAP和GnRH类似物本身都不具有细胞毒性。这些结果表明，GnRH类似物可用于将毒素分子特异性地输送到表达GnRH受体的细胞中。因此，一类新的生物药物作为激素毒素来对抗表达GnRH受体的细胞，为抑制生殖和治疗依赖生殖激素的癌症提供了一种新的途径。
Pokeweed antiviral protein (PAP), a 29-kDa ribosome-inactivating protein isolated from the leaves of Phytolacca americana, has potent cytotoxic activity once it enters the cytoplasm of a cell. It is incapable of entering cells by itself. Therefore, our objective was to determine whether a GnRH analog could be used to deliver PAP specifically to cells expressing GnRH receptors. D-Lys(6)-GnRH-Pro(9)-ethylamide was conjugated to PAP (GnRH-PAP). Chinese hamster ovary cells stably transfected with cDNA for the murine GnRH receptor and a mouse gonadotroph tumor cell line that expresses endogenous GnRH receptors (alphaT3-1 cells) were used to evaluate the cytotoxic effects of GnRH-PAP. We also examined cytotoxicity of GnRH-PAP using human endometrial, breast, and prostate cancer cell lines. Treatment of GnRH receptor-positive cells with GnRH-PAP resulted in dose-dependent cytotoxicity. Cytotoxicity of GnRH-PAP was dependent on number of GnRH receptors (r(2) = 0.871, P < 0.05) and duration of exposure of GnRH-PAP to the cells. In contrast, GnRH-PAP was not cytotoxic to Chinese hamster ovary cells not harboring GnRH receptors. Moreover, the cytotoxic activity of GnRH-PAP could be inhibited by addition of excess GnRH analog. Neither PAP nor GnRH analog alone was cytotoxic. These results suggest that GnRH analogs can be used to specifically deliver toxin molecules to cells that express GnRH receptors. Thus, a new class of biomedicines that act as hormonotoxins against cells expressing GnRH receptors provides a novel approach for inhibiting reproduction and treating cancers that are dependent on reproductive hormones.