Expression, induction and regulation of the cytochrome P450 monooxygenase system in the rat glioma C6 cell line.
Expression, induction and regulation of the cytochrome P450 monooxygenase system in the rat glioma C6 cell line.
复制标题
细胞色素 P450 单加氧酶系统在大鼠神经胶质瘤 C6 细胞系中的表达、诱导和调节。
DOI：
10.1016/s0006-8993(97)01346-2
复制
发表时间：
1998
期刊：
影响因子：
2.9
通讯作者：
Strobel,HW
中科院分区：
文献类型：
--
作者：
Geng,J;Strobel,HW
细胞色素P450单加氧酶系统由NADPH-细胞色素P450还原酶(P450还原酶)和细胞色素P450组成，可催化多种内源和外源化合物的氧化。P450还原酶将还原型从NADPH转移到P450，进而催化代谢反应。在以前的研究中，我们已经使用大鼠胶质瘤C6细胞系作为体外模型系统，通过逆转录-聚合酶链式反应(RT-PCR)鉴定了P450还原酶和细胞色素P450 1A1、1A2、2A1、2B1/2、2C7、2D1-5和2E1的存在。在C6细胞中，BA(苯并(A)菲)或PB(苯巴比妥)处理后，P4501A1和2B1/2在mRNA水平上被诱导。在本研究中，通过对胶质瘤C6细胞微粒体标本的分析，在蛋白质水平上证明了P450 2B和P450还原酶的存在。ELISAs结果显示，PB诱导的P450 2B蛋白增加了12倍。这些实验进一步证实，大鼠胶质瘤C6细胞系含有活性的细胞色素P450单加氧酶系统，该系统可被P450诱导剂诱导。我们还发现，来自胶质瘤C6细胞的P450 1A1和2B1/2的mRNAs不能有效地与基于寡核苷酸(DT)的分离技术结合，这表明它们可能有非常短的Poly(A)尾巴。P4501A1和2B1/2mRNA在胶质瘤C6细胞中的半衰期分别为肝脏的1/10和1/3。这可能是P450在神经胶质细胞中低表达的部分原因。BA或PB对P450的诱导没有改变它们的mRNA半衰期，提示这种诱导可能是由于转录调节所致。综上所述，我们认为脑胶质细胞中细胞色素P450单加氧酶系统的存在可能在脑肿瘤的化疗和癌变中起重要作用。
The cytochrome P450 monooxygenase system consists of NADPH-cytochrome P450 reductase (P450 reductase) and cytochromes P450, which can catalyze the oxidation of a wide variety of endogenous and exogenous compounds. P450 reductase transfers reducing equivalents from NADPH to P450, which in turn catalyzes metabolic reactions. In previous studies, we have used the rat glioma C6 cell line as an in vitro model system and identified the presence of P450 reductase and of cytochrome P450 1A1, 1A2, 2A1, 2B1/2, 2C7, 2D1-5 and 2E1 by reverse transcription followed by polymerase chain reaction (RT–PCR). In C6 cells, the induction of P450 1A1 and 2B1/2 at mRNA level after BA (benzo(a)anthracene) or PB (phenobarbital) treatments was detected. In this study, analysis of microsomal preparations of glioma C6 cells was utilized to demonstrate the presence of P450 2B and P450 reductase at the protein level. ELISAs showed that PB induced P450 2B proteins 12-fold. These experiments further establish that the rat glioma C6 cell line contains an active cytochrome P450 monooxygenase system that can be induced by P450 inducers. We also found that the mRNAs of P450 1A1 and 2B1/2 from glioma C6 cells do not bind to the oligo(dT)-based separation techniques efficiently, suggesting that they may have very short poly(A) tails. The half-lives of P450 1A1 and 2B1/2 mRNA in glioma C6 cells are 1/10 and 1/3 of that in liver, respectively. This may partly contribute to the low expression level of P450s in glial cells. The induction of P450s by BA or PB did not change their mRNA half-lives, indicating the induction may be due to transcriptional regulation. In summary of this study, we believe the presence of the cytochrome P450 monooxygenase system in glial cells of the brain may be important in chemotherapy and carcinogenesis of brain tumors.