Inhibition of NADPH oxidase 4 activates apoptosis via the AKT/apoptosis signal-regulating kinase 1 pathway in pancreatic cancer PANC-1 cells
Inhibition of NADPH oxidase 4 activates apoptosis via the AKT/apoptosis signal-regulating kinase 1 pathway in pancreatic cancer PANC-1 cells
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DOI：
10.1038/sj.onc.1209406
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发表时间：
2006-06-22
期刊：
影响因子：
8
通讯作者：
Kamata, T.
中科院分区：
文献类型：
--
作者：
Mochizuki, T.;Furuta, S.;Kamata, T.
胰腺腺癌是一种侵袭性的人类恶性肿瘤，其特点是细胞凋亡抵抗。最近，NADPH氧化酶（Nox） 4介导的细胞内活性氧（ROS）的产生被认为具有抗凋亡活性，从而使胰腺癌细胞具有生长优势。Nox4传递细胞存活信号的信号机制尚不清楚。本研究表明，黄素蛋白抑制剂二苯基碘（DPI）和设计用于靶向Nox4 mRNA （siNox4R-NAs）的小干扰rna都能抑制PANC-1胰腺癌细胞中超氧化物的产生，DPI或sinox4rna对ROS的消耗诱导细胞凋亡。同样，DPI处理和siNox4RNA转染通过减弱AKT的磷酸化来阻断细胞存活激酶AKT的激活。此外，DPI和sinox4rna降低了AKT磷酸化Ser-83的凋亡信号调节激酶1 （ASK1）。当ASK1Ser83Ala （AKT磷酸化缺陷ASK1突变体）导入PANC-1细胞时，该突变体单独诱导细胞凋亡。而添加DPI或共转染siNox4RNA均无加性作用，说明突变体可以替代这些试剂诱导细胞凋亡。综上所述，这些发现表明，在胰腺癌细胞中，Nox4产生的ROS至少部分通过AKT ASK1途径传递细胞存活信号，其耗竭导致细胞凋亡。
Pancreatic adenocarcinoma is an aggressive human malignancy and is characterized by resistance to apoptosis. Recently, NADPH oxidase ( Nox) 4-mediated generation of intracellular reactive oxygen species ( ROS) was proposed to confer antiapoptotic activity and thus a growth advantage to pancreatic cancer cells. The signaling mechanism by which Nox4 transmits cell survival signals remains unclear. Here, we show that both a flavoprotein inhibitor, diphenylene iodonium ( DPI), and small interfering RNAs designed to target Nox4 mRNA ( siNox4R-NAs) inhibited superoxide production in PANC-1 pancreatic cancer cells, and depletion of ROS by DPI or siNox4RNAs induced apoptosis. Parallely, DPI treatment and siNox4RNA transfection blocked activation of the cell survival kinase AKT by attenuating phosphorylation of AKT. Furthermore, AKT phosphorylation of apoptosis signal-regulating kinase 1 ( ASK1) on Ser-83 was reduced by DPI and siNox4RNAs. When ASK1Ser83Ala ( an AKT phosphorylation-defective ASK1 mutant) was introduced into PANC-1 cells, this mutant alone induced apoptosis. But, addition of DPI or co-transfection of siNox4RNA had no additive effect, indicating that the mutant can substitute for these reagents in apoptosis induction. Taken together, these findings suggest that ROS generated by Nox4, at least in part, transmit cell survival signals through the AKT ASK1 pathway in pancreatic cancer cells and their depletion leads to apoptosis.