NADPH oxidase isoform selective regulation of endothelial cell proliferation and survival
NADPH oxidase isoform selective regulation of endothelial cell proliferation and survival
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DOI：
10.1007/s00210-009-0413-0
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发表时间：
2009-08-01
影响因子：
3.6
通讯作者：
Selemidis, Stavros
中科院分区：
文献类型：
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作者：
Peshavariya, Hitesh;Dusting, Gregory J.;Selemidis, Stavros
内皮细胞的增殖和凋亡是导致肿瘤发生和发展的重要血管生成过程。新出现的证据表明，活性氧（ROS），如超氧化物和过氧化氢（H2 O2）的增殖和凋亡的调节。在本研究中，我们通过检测这些酶系统对（1）特异性增殖和致瘤激酶，细胞外调节激酶1/2（ERK 1/2）和Akt，（2）细胞骨架组织，（3）影响细胞凋亡的机制。ROS的产生和NADPH氧化酶亚基Nox 4的表达，但不是Nox 2，显着高于在静止的内皮细胞增殖。添加H2 O2清除剂过氧化氢酶或用特异性siRNA下调Nox 4蛋白可降低ROS水平、细胞增殖和ERK 1/2磷酸化，但对细胞形态或caspase 3/7活性没有影响。虽然用siRNA下调Nox 2蛋白也减少了ROS的产生和细胞增殖，但它引起了caspase 3/7活性的增加，减少了Akt磷酸化，并引起了细胞骨架的解体。因此，在内皮细胞中，Nox 4衍生的H2 O2激活ERK 1/2以促进增殖，而含Nox 2的NADPH氧化酶维持细胞骨架并防止凋亡以支持细胞存活。我们的研究为支持内皮细胞存活的分子机制提供了新的理解，并为联合抑制含Nox 4和Nox 2的NADPH氧化酶用于癌症中不必要的血管生成提供了理论基础。
Proliferation and apoptosis of endothelial cells are crucial angiogenic processes that contribute to carcinogenesis and tumor progression. Emerging evidence implicates the regulation of proliferation and apoptosis by reactive oxygen species (ROS) such as superoxide and hydrogen peroxide (H2O2). In the present study, we investigated the roles of the ROS-generating Nox4- and Nox2-containing reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidases in proliferation of human endothelial cells by examining the impact of these enzyme systems on (1) specific proliferative and tumorigenic kinases, extracellular regulated kinase1/2 (ERK1/2) and Akt, (2) cytoskeletal organization, and (3) the mechanisms that influence cellular apoptosis. ROS production and the expression of NADPH oxidase subunit Nox4, but not Nox2, were markedly higher in proliferating than in quiescent endothelial cells. Addition of the H2O2 scavenger catalase or downregulation of Nox4 protein with specific siRNA reduced ROS levels, cell proliferation, and ERK1/2 phosphorylation but had no effect on either cell morphology or caspase 3/7 activity. Although downregulation of Nox2 protein with siRNA also reduced ROS production and cell proliferation, it caused an increase in caspase 3/7 activity, reduced Akt phosphorylation, and caused cytoskeletal disorganization. Therefore, in endothelial cells, Nox4-derived H2O2 activates ERK1/2 to promote proliferation, whereas Nox2-containing NADPH oxidase maintains the cytoskeleton and prevents apoptosis to support cell survival. Our study provides a new understanding of the molecular mechanisms that underpin endothelial cell survival and a rationale for the combined suppression of Nox4- and Nox2-containing NADPH oxidases for unwanted angiogenesis in cancer.