2-methoxyestradiol-induced phosphorylation of Bcl-2:: Uncoupling from JNK/SAPK activation
2-methoxyestradiol-induced phosphorylation of Bcl-2:: Uncoupling from JNK/SAPK activation
复制标题
DOI：
10.1006/bbrc.1998.8870
复制
发表时间：
1998-06-29
影响因子：
3.1
通讯作者：
Mäkelä, TP
中科院分区：
文献类型：
--
作者：
Attalla, H;Westberg, JA;Mäkelä, TP
天然雌激素代谢产物2-甲氧基雌二醇(2Me)在体内具有抗血管生成作用，在体外具有较强的生长抑制作用。这种生长抑制是由于有丝分裂停止和细胞凋亡所致。这些效应类似于紫杉醇诱导的效应，并且似乎是通过抑制微管动力学来实现的。在这里，我们研究了细胞对2Me的反应，就是关于观察到的细胞变化的潜在介质。2与紫杉醇类似，微管解聚药物秋水仙碱和长春新碱能增加细胞微管蛋白的不溶性聚合率。2Me处理后的这种稳定伴随着2-24小时内Bcl2的磷酸化和失活逐渐增加。为了研究导致Bcl2磷酸化的途径，我们分析了Raf-1和JNK/SAPK激酶，这两个激酶都被报道参与了Bcl2的失活。我们的结果表明，Raf-1对2Me的反应是磷酸化的，但这发生在Bcl2的磷酸化之后，这表明Raf-1并不直接磷酸化Bcl2。2Me处理后，JNK/SAPK迅速激活。然而，这种激活是短暂的，并在处理2小时后恢复到检测不到的水平，表明JNK/SAPK不是直接磷酸化Bcl-2。结合先前的研究结果表明，JNK/SAPK的过度表达导致了Bcl2的磷酸化，我们的结果支持JNK/SAPK间接磷酸化Bcl2的模型。(C)1998年学术出版社。
The natural estrogen metabolite 2-methoxyestradiol (2ME) is anti-angiogenic in vivo and a strong growth inhibitor in vitro. The growth inhibition is due to mitotic arrest and apoptosis. These effects are reminiscent of those induced by taxol, and appear to be mediated by inhibition of microtubule dynamics. Here we have studied the cellular response to 2ME in regard to potential mediators of the observed cellular changes. 2ME treatment increases the insoluble polymerized fraction of cellular tubulin similar to taxol, and in contrast to the microtubule depolymerizing drugs such as colcemid and vincristine. This stabilization following 2ME treatment is accompanied by phosphorylation and inactivation of Bcl-2 increasing gradually hom 2-24 hours. To study the pathway leading to Bcl-2 phosphorylation we analyzed Raf-1 and JNK/SAPK kinases, both of which have been reported to be involved in Bcl-2 inactivation. Our results indicate that Raf-1 is phosphorylated in response to 2ME, but this occurs later than Bcl-2 phosphorylation suggesting that Raf-1 is not directly phosphorylating Bcl-2. JNK/SAPK was activated rapidly after 2ME treatment. However, this activation was transient and returned to undetectable levels by 2 hours of treatment, demonstrating that JNK/SAPK is not directly phosphorylating Bcl-2. Taken together with previous results indicating that overexpression of JNK/SAPK leads to Bcl-2 phosphorylation, our results would support a model where JNK/SAPK is indirectly phosphorylating Bcl-2. (C) 1998 Academic Press.