The p53 pathway promotes efficient mitochondrial DNA base excision repair in colorectal cancer cells
The p53 pathway promotes efficient mitochondrial DNA base excision repair in colorectal cancer cells
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DOI：
10.1158/0008-5472.can-05-4103
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发表时间：
2006-04-01
期刊：
影响因子：
11.2
通讯作者：
Lopez, CD
中科院分区：
文献类型：
--
作者：
Chen, DX;Yu, ZY;Lopez, CD
抑癌基因p53在DNA损伤反应中起着重要作用。p53增强碱基切除修复（BER），部分是通过与修复复合物的直接相互作用。线粒体DNA（mtDNA）是通过mtBER途径修复的。许多结直肠癌含有与预后不良相关的mtDNA突变。除了调节细胞凋亡反应，p53也刺激mtBER。然而，p53在应激后增强结直肠癌mtBER的机制仍不清楚。为了探索这一点，我们使用了与p53同基因的结直肠癌细胞（HCT 116 p53 +/+和HCT 116 p53-/-）。p53+/+细胞更有效地修复H2 O2损伤的DNA在体内通过半定量mtDNA位移，环PCR测量。来自p53+/+细胞的线粒体提取物更有效地刺激P-32-dCTP掺入尿嘧啶寡核苷酸。重组p53补充了尿嘧啶或含8-氧代-G的寡核苷酸的p53-/-线粒体提取物修复。作为DNA糖基化酶活性的量度，p53+/+线粒体提取物更有效地切割尿嘧啶或8-氧代-G寡核苷酸，尽管重组p53不能刺激寡核苷酸切割。p53没有。影响线粒体脱嘌呤/脱嘧啶核酸内切酶活性。p53+/+线粒体提取物具有更高的DNA聚合酶-γ活性，通过将P-32-dCTP掺入到单核苷酸缺口寡核苷酸中来测量，并且重组p53补充了p53-/-线粒体提取物DNA聚合酶-γ活性。mtDNA连接酶活性不受p53状态的影响。p53蛋白在线粒体内膜亚组分中检测到，该亚组分含有mtBER复合物的成分。我们的数据显示。完整的p53通路刺激特定的mtBER步骤，并为结直肠癌中mtDNA突变的发展提供了机制性的见解。
The tumor suppressor p53 plays a central role in the DNA damage response. p53 enhances base excision repair (BER), in part, through direct interaction with the repair complex. Mitochondrial DNA (mtDNA) is repaired by a mtBER pathway. Many colorectal cancers harbor mtDNA mutations that are associated with poor prognosis. In addition to modulating the apoptotic response, mitochondria-localized p53 also stimulates mtBER. However, the mechanisms by which p53 enhances colorectal cancer mtBER after stress remain unclear. To explore this, we used colorectal cancer cells isogenic for p53 (HCT116p53+/+ and HCT116p53-/-). p53+/+ cells more efficiently repaired H2O2 damaged DNA in vivo as measured by semiquantitative mtDNA displacement, loop PCR. Mitochondrial extracts from p53+/+ cells more efficiently stimulated P-32-dCTP incorporation into a uracil-oligonucleotide. Recombinant p53 complemented p53-/- mitochondrial extract repair of uracil or 8-oxo-G-containing oligonucleotides. As a measure of DNA glycosylase activity, p53+/+ mitochondrial extracts more efficiently incised uracil or 8-oxo-G oligonucleotides, although recombinant p53 could not stimulate oligonucleotide incision. p53 did not. influence mitochondrial apurinic/apyrimidime endonuclease activity measured by incision of a tetrahydrofuran-oligonucleotide. p53+/+ mitochondrial extracts had higher DNA polymerase-gamma activity measured by P-32-dCTP incorporation into a single-nucleotide gap oligonucleotide, and recombinant p53 complemented p53-/- mitochondrial extract DNA polymerase-gamma activity. mtDNA ligase activity wits not affected by p53 status. p53 protein was detected in an inner mitochondrial membrane subfraction containing components of the mtBER complex. Our data suggest that. an intact p53 pathway stimulates specific mtBER steps and provides mechanistic insight into the development, of mtDNA mutations in colorectal cancer.