Regulation of p53 and suppression of apoptosis by the soluble guanylyl cyclase/cGMP pathway in human ovarian cancer cells
Regulation of p53 and suppression of apoptosis by the soluble guanylyl cyclase/cGMP pathway in human ovarian cancer cells
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DOI：
10.1038/sj.onc.1209251
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发表时间：
2006-04-01
期刊：
影响因子：
8
通讯作者：
Tsang, BK
中科院分区：
文献类型：
--
作者：
Fraser, M;Chan, SL;Tsang, BK
失调的细胞凋亡在许多异常细胞过程的发展中起着关键作用，包括肿瘤发生和化疗耐药。然而，控制正常细胞凋亡程序的机制尚未完全了解。可溶性鸟苷酸环化酶 (sGC) 和环鸟苷单磷酸 (cGMP) 通过未知机制促进哺乳动物细胞活力，p53 状态是人卵巢癌细胞中细胞命运的关键决定因素。这两个细胞命运决定因素之间是否存在相互作用尚不清楚。我们假设基础 sGC 活性会降低人卵巢癌细胞中 p53 含量并减弱 p53 依赖性细胞凋亡。使用特异性抑制剂 1H-[1,2,4] 恶二唑并[4,3-a] 喹喔啉-1-酮 (ODQ) 抑制 sGC 活性，可降低三种卵巢癌细胞系中的 cGMP 含量，增加 p53 蛋白含量并诱导细胞凋亡，cGMP 类似物 8-Br-cGMP 和心房利尿钠因子（一种 颗粒鸟苷酸环化酶，可规避 sGC 的抑制作用。 ODQ延长p53半衰期，诱导p53 Ser15磷酸化，并上调p53依赖性基因产物p21、鼠双分钟-2和促凋亡、p53反应性基因产物Bax。 ODQ 激活 caspase-3，并且 X 连锁凋亡抑制蛋白的过度表达可抑制 ODQ 诱导的细胞凋亡。用特定的 p53 抑制剂 Pifithrin 预处理或使用特定的小抑制性 RNA 下调 p53 可显着减弱 ODQ 诱导的细胞凋亡。此外，相对于野生型亲本细胞系，p53突变细胞系中ODQ诱导的p21和Bax上调以及ODQ诱导的细胞凋亡显着减少。因此，目前的研究表明，基础 sGC/cGMP 活性可能通过改变 p53 磷酸化和稳定性来调节 p53 蛋白的稳定性、含量和功能，并部分通过调节 caspase-3 和 p53 来促进细胞存活。
Dysregulated apoptosis plays a critical role in the development of a number of aberrant cellular processes, including tumorigenesis and chemoresistance. However, the mechanisms that govern the normal apoptotic program are not completely understood. Soluble guanylyl cyclase (sGC) and cyclic guanosine monophosphate ( cGMP) promote mammalian cell viability via an unknown mechanism and p53 status is a key determinant of cell fate in human ovarian cancer cells. Whether an interaction exists between these two determinants of cell fate is unknown. We hypothesized that basal sGC activity reduces p53 content and attenuates p53-dependent apoptosis in human ovarian cancer cells. Suppression of sGC activity with the specific inhibitor 1H-[1,2,4] oxadiazolo[ 4,3-a] quinoxalin-1-one (ODQ) lowered cGMP content, and increased p53 protein content and induced apoptosis in three ovarian cancer cell lines, effects which were attenuated by the cGMP analog 8-Br-cGMP and by Atrial Natriuretic Factor, an activator of particulate guanylyl cyclase, which circumvent the inhibition of sGC. ODQ prolonged p53 half-life, induced phosphorylation of p53 on Ser15, and upregulated the p53- dependent gene products p21, murine double minute-2, and the proapoptotic, p53- responsive gene product Bax. ODQ activated caspase-3, and ODQ-induced apoptosis was inhibited by overexpression of X-linked inhibitor of apoptosis Protein. Pretreatment with the specific p53 inhibitor pifithrin or downregulation of p53 using a specific small inhibitory RNA significantly attenuated ODQ-induced apoptosis. Moreover, ODQ-induced upregulation of p21 and Bax and ODQ-induced apoptosis were significantly reduced in a p53 mutant cell line relative to the wild-type parental cell line. Thus, the current study establishes that basal sGC/cGMP activity regulates p53 protein stability, content, and function, possibly by altering p53 phosphorylation and stabilization, and promotes cell survival in part through regulation of caspase-3 and p53.