Glucocorticoids in malignant lymphoid cells: gene regulation and the minimum receptor fragment for lysis.
Glucocorticoids in malignant lymphoid cells: gene regulation and the minimum receptor fragment for lysis.
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恶性淋巴细胞中的糖皮质激素：基因调控和裂解的最小受体片段。
DOI：
10.1016/0960-0760(92)90352-j
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
Johnson,BH
中科院分区：
文献类型：
--
作者：
Thompson,EB;Nazareth,LV;Thulasi,R;Ashraf,J;Harbour,D;Johnson,BH
我们已经检查了人类恶性淋巴细胞克隆的标记物，与糖皮质激素介导的细胞溶解。在糖皮质激素敏感的CEM（一种人T细胞淋巴母细胞白血病细胞系）克隆中，有两个基因与糖皮质激素诱导的细胞溶解相关。糖皮质激素受体（GR）本身在敏感克隆中由标准糖皮质激素诱导，而在不敏感克隆中不诱导。苯基吡唑并糖皮质激素可替唑（CVZ）能够裂解对高浓度标准强效糖皮质激素具有抗性的几个克隆。当测试这些克隆的cortivazol反应时，它们不仅被cortivazol裂解，而且还显示GR mRNA的诱导。因此，受体诱导似乎与这些细胞中受体的裂解功能相关。为了确定GR的哪些部分是裂解所需的，我们通过在GR缺陷的CEM克隆中表达GR和GR片段基因来映射此功能。我们的研究结果表明，没有已知的反式激活区域的GR是必需的。去除类固醇结合结构域得到完全组成型的片段。仅需要DNA结合区的一个半“Zn指”。我们还发现在CEM细胞中c-myc原癌基因的快速抑制，糖皮质激素导致生长停滞和细胞溶解。这仅发生在同时具有完整受体和裂解功能的克隆中。因此，单纯GR的存在不足以保证c-myc下调。由不允许糖皮质激素抑制的启动子驱动的c-myc导入细胞赋予对类固醇的抗性。此外，通过反义寡核苷酸抑制c-myc也杀死细胞。因此，c-myc似乎是一个关键的基因，既与类固醇的杀伤能力和细胞活力。
We have examined clones of human malignant lymphoid cells for markers that correlate with glucocorticoid-mediated cell lysis. In glucocorticoid-sensitive clones of CEM, a human T-cell lymphoblastic leukemia line, two genes correlate with glucocorticoid-induced cell lysis. The glucocorticoid receptor (GR) itself is induced by standard glucocortoids in sensitive clones and not in insensitive clones. The phenylpyrazolo-glucocortocoid cortivazol (CVZ) is capable of lysing several clones resistant to high concentrations of standard potent glucocorticoids. When these clones were tested for cortivazol responses, they were not only lysed by cortivazol but also showed induction of GR mRNA. Thus receptor induction appears to correlate with the lysis function of receptor in these cells. To determine what parts of the GR are required for lysis, we have mapped this function by transfecting and expressing GR and GR fragment genes in a GR-deficient CEM clone. Our results indicate that none of the known trans-activation regions of the GR are required. Removal of the steroid binding domain gives a fragment that is fully constitutive. Only one and one-half “Zn fingers” of the DNA binding region are required. We also find in CEM cells rapid suppression of the c-myc protooncogene, proceding growth arrest and cell lysis by glucocorticoids. This occurs only in clones possessing both intact receptors and lysis function. Thus the simple presence of GR alone is not sufficient to guarantee c-myc down-regulation. Introduction into the cells of c-myc driven by a promoter that does not permit suppression by glucocorticoids confers resistance to steroids. Furthermore, suppression of c-myc by antisense oligonucleotides also kills the cells. Therefore, c-myc appears to be a pivotal gene related both to ability of steroid to kill and to cell viability.