The involvement of the tyrosine kinase c-Src in the regulation of reactive oxygen species generation mediated by NADPH oxidase-1
The involvement of the tyrosine kinase c-Src in the regulation of reactive oxygen species generation mediated by NADPH oxidase-1
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DOI：
10.1091/mbc.e08-02-0138
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发表时间：
2008-07-01
影响因子：
3.3
通讯作者：
Bokoch, Gary M.
中科院分区：
文献类型：
--
作者：
Gianni, Davide;Bohl, Ben;Bokoch, Gary M.
NADPH氧化酶（Nox）家族酶是细胞活性氧（ROS）的主要来源之一，其已被证明作为第二信使分子起作用。迄今为止，已报道了该家族的7个成员，包括Nox 1 -5和Duox 1和-2。除了Nox 2之外，Nox酶的调节仍然知之甚少。Nox 1在结肠中高度表达，并且其活性需要两种胞质调节剂NoxO 1和NoxA 1以及Rac 1 GT3的结合。在这项研究中，我们调查的作用酪氨酸激酶c-Src的ROS形成的Nox 1的调节。我们发现，c-Src诱导Nox 1介导的ROS产生在HT 29人结肠癌细胞系通过Rac依赖的机制。用Src抑制剂PP 2处理HT 29细胞，表达c-Src的激酶失活形式，并通过小干扰RNA（siRNA）消除c-Src，从而降低ROS的产生和活性Rac 1的水平。这与减少Src介导的磷酸化和Rac 1-鸟嘌呤核苷酸交换因子Vav 2的激活有关。与此一致，特异性降低内源性Vav 2蛋白的Vav 2 siRNA能够显著降低Nox 1依赖性ROS的产生并消除c-Src诱导的Nox 1活性。总之，这些结果确立了c-Src作为Nox 1活性的重要调节因子，并且它们可以提供对结肠癌肿瘤形成机制的深入了解。
NADPH oxidase (Nox) family enzymes are one of the main sources of cellular reactive oxygen species (ROS), which have been shown to function as second messenger molecules. To date, seven members of this family have been reported, including Nox1-5 and Duox1 and -2. With the exception of Nox2, the regulation of the Nox enzymes is still poorly understood. Nox1 is highly expressed in the colon, and it requires two cytosolic regulators, NoxO1 and NoxA1, as well as the binding of Rac1 GTPase, for its activity. In this study, we investigate the role of the tyrosine kinase c-Src in the regulation of ROS formation by Nox1. We show that c-Src induces Nox1-mediated ROS generation in the HT29 human colon carcinoma cell line through a Rac-dependent mechanism. Treatment of HT29 cells with the Src inhibitor PP2, expression of a kinase-inactive form of c-Src, and c-Src depletion by small interfering RNA (siRNA) reduce both ROS generation and the levels of active Rac1. This is associated with decreased Src-mediated phosphorylation and activation of the Rac1-guanine nucleotide exchange factor Vav2. Consistent with this, Vav2 siRNA that specifically reduces endogenous Vav2 protein is able to dramatically decrease Nox1-dependent ROS generation and abolish c-Src-induced Nox1 activity. Together, these results establish c-Src as an important regulator of Nox1 activity, and they may provide insight into the mechanisms of tumor formation in colon cancers.