Elevated ornithine decarboxylase levels activate ataxia telangiectasia mutated-DNA damage signaling in normal keratinocytes.
Elevated ornithine decarboxylase levels activate ataxia telangiectasia mutated-DNA damage signaling in normal keratinocytes.
复制标题
鸟氨酸脱羧酶水平升高会激活正常角质形成细胞中的共济失调毛细血管扩张突变 DNA 损伤信号。
DOI：
10.1158/0008-5472.can-07-5030
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发表时间：
2008
期刊：
影响因子：
11.2
通讯作者：
Gilmour,SusanK
中科院分区：
文献类型：
--
作者：
Wei,Gang;DeFeo,Karen;Hayes,CandaceS;Woster,PatrickM;Mandik-Nayak,Laura;Gilmour,SusanK
我们研究了鸟氨酸脱羧酶（ODC），在多胺生物合成的关键限速酶的表达增加的影响，在原代培养的角质形成细胞从K6/ODC转基因小鼠（Ker/ODC）和他们的正常同窝出生（Ker/Norm）的皮肤分离的细胞存活。尽管ODC和多胺水平升高刺激角质形成细胞增殖，但Ker/ODC在原代培养的数天内经历凋亡性细胞死亡，不像Ker/Norm继续增殖。在Ker/ODC和K6/ODC转基因皮肤中，共济失调毛细血管扩张突变（ATM）及其底物p53的磷酸化被显著诱导。染色质免疫沉淀分析表明，在Ker/ODC中，p53水平的增加伴随着p53向近端启动子的募集增加。ATM的活化依赖于多胺，因为ODC活性的特异性抑制剂α-二氟甲基鸟氨酸阻断其磷酸化。Ker/ODC还显示H2O2、丙烯醛-赖氨酸缀合物和蛋白质氧化产物的产生增加，以及多胺依赖性DNA损伤，如通过彗星试验和组蛋白变体γ H2AX的磷酸化形式的表达所测量的。Ker/ODC的活性氧生成和凋亡细胞死亡可能至少部分是由于诱导产生H2O2和细胞毒性醛的多胺分解代谢途径，因为精胺氧化酶（SMO）水平在Ker/ODC中被诱导。此外，用SMO抑制剂MDL 72，527处理，阻断H2O2的产生并增加Ker/ODC的存活。这些结果表明，在非致瘤性角质形成细胞中，ATM-DNA损伤信号通路响应于ODC活性增加而被新激活。[Cancer Res 2008; 68（7）：2214 - 22]
We examined the effect of increased expression of ornithine decarboxylase (ODC), a key rate-limiting enzyme in polyamine biosynthesis, on cell survival in primary cultures of keratinocytes isolated from the skin of K6/ODC transgenic mice (Ker/ODC) and their normal littermates (Ker/Norm). Although elevated levels of ODC and polyamines stimulate proliferation of keratinocytes, Ker/ODC undergo apoptotic cell death within days of primary culture unlike Ker/Norm that continue to proliferate. Phosphorylation of ataxia telangiectasia mutated (ATM) and its substrate p53 are significantly induced both in Ker/ODC and in K6/ODC transgenic skin. Chromatin immunoprecipitation analyses show that the increased level of p53 in Ker/ODC is accompanied by increased recruitment of p53 to theBaxproximal promoter. ATM activation is polyamine dependent because α-difluoromethylornithine, a specific inhibitor of ODC activity, blocks its phosphorylation. Ker/ODC also displays increased generation of H2O2, acrolein-lysine conjugates, and protein oxidation products as well as polyamine-dependent DNA damage, as measured by the comet assay and the expression of the phosphorylated form of the histone variant γH2AX. Both reactive oxygen species generation and apoptotic cell death of Ker/ODC may, at least in part, be due to induction of a polyamine catabolic pathway that generates both H2O2and cytotoxic aldehydes, because spermine oxidase (SMO) levels are induced in Ker/ODC. In addition, treatment with MDL 72,527, an inhibitor of SMO, blocks the production of H2O2and increases the survival of Ker/ODC. These results show a novel activation of the ATM-DNA damage signaling pathway in response to increased ODC activity in nontumorigenic keratinocytes. [Cancer Res 2008;68(7):2214–22]