POSTTRANSCRIPTIONAL DOWN-REGULATION OF RAS ONCOGENE EXPRESSION BY INHIBITORS OF CELLULAR GLUTATHIONE
POSTTRANSCRIPTIONAL DOWN-REGULATION OF RAS ONCOGENE EXPRESSION BY INHIBITORS OF CELLULAR GLUTATHIONE
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DOI：
10.1128/mcb.13.7.4416
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发表时间：
1993-07-01
影响因子：
5.3
通讯作者：
SAMID, D
中科院分区：
文献类型：
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作者：
MILLER, AC;GAFNER, J;SAMID, D
细胞内谷胱甘肽（GSH）含量的改变影响电离辐射的内在反应。最近，很明显，辐射反应也可能取决于特定的癌基因，包括ras的表达。这些发现表明GSH和ras之间可能存在联系，这使我们研究了各种GSH调节剂对ras表达的影响。用L-丁硫氨酸、S 'R'-亚砜亚胺、富马酸二甲酯或N '，N'-1，3-双（反式-4-羟基环己基）-N '-亚硝基脲处理c-Ha-ras转化的NIH 3 T3细胞，导致ras mRNA稳态水平的剂量和时间依赖性降低，随后ras编码的p21蛋白产生减少。对ras的影响与GSH下降的程度相关，对ras家族的不同成员是常见的，并且与癌基因激活或细胞表型的模式无关。事实上，在c-Ha-ras原癌基因过表达是由于转录激活（PR 4，非致瘤性）或基因扩增（NIH 136，致瘤性）的鼠细胞和表达突变Ha-ras（RS 504）的恶性细胞中观察到了相似的药物作用。此外，人肿瘤细胞中的N-ras、EJras和Ki-ras也受到类似的影响。分子分析显示，在细胞中的ras mRNA的半衰期受到GSH抑制，需要从头蛋白质合成的效果显着减少，但没有变化的基因转录速率。这些结果表明，细胞GSH含量的药理学操作可以下调ras的表达在转录后水平的不稳定的ras转录。潜在的临床意义进行了讨论。
Alterations in intracellular glutathione (GSH) content are known to affect intrinsic responses to ionizing radiation. More recently, it became apparent that radiation responses may depend also on the expression of specific oncogenes, including ras. These findings, suggesting a possible link between GSH and ras, led us to examine the effect of various GSH modulators on ras expression. Treatment of c-Ha-ras-transformed NIH 3T3 cells with L-buthionine S'R'-sulfoximine, dimethylfumarate, or N',N'-1,3-bis(trans-4-hydroxycyclohexyl)-N'-nitrosourea resulted in dose- and time-dependent reduction in ras mRNA steady-state levels followed by a decrease in ras-encoded p21 protein production. The effect on ras correlated with the extent of GSH decline, was common to different members of the ras family, and was independent of the mode of oncogene activation or cell phenotype. Indeed, similar drug effects were observed with murine cells in which overexpression of the c-Ha-ras proto-oncogene was due to transcriptional activation (PR4, nontumorigenic) or gene amplification (NIH 136, tumorigenic) and with malignant cells expressing a mutated Ha-ras (RS504). Moreover, N-ras, EJras, and Ki-ras in human tumor cells were similarly affected. Molecular analysis revealed a significant decrease in ras mRNA half-life in cells subjected to GSH inhibition, an effect that required de novo protein synthesis, but there was no change in the rate of gene transcription. These results indicate that pharmacological manipulation of cellular GSH content can down-regulate ras expression at the posttranscriptional level by destabilizing ras transcripts. The potential clinical implications are discussed.