Modulation of CDK2-AP1 (p12DOC-1) expression in human colorectal cancer
Modulation of CDK2-AP1 (p12DOC-1) expression in human colorectal cancer
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DOI：
10.1038/sj.onc.1208378
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发表时间：
2005-05-19
期刊：
影响因子：
8
通讯作者：
Weber, TK
中科院分区：
文献类型：
--
作者：
Yuan, ZQ;Gaba, AG;Weber, TK
我们先前已经证明了微卫星不稳定性与人结直肠癌（CRC）细胞系中CDK 2-AP 1（p12（DOC-1））表达降低之间的相关性。在这些相同的研究中，诱导CDK 2-AP 1表达促进细胞周期停滞和凋亡。本研究的目的是更好地了解导致微卫星不稳定（MSI）CRC中CDK 2-AP 1表达降低的机制，并利用RNA干扰（RNAi）技术进一步研究CDK 2-AP 1调节对细胞增殖和凋亡的影响。我们采用直接测序法对24个结直肠癌细胞系中CDK 2-AP 1基因3'端的poly（T）8微卫星样区域进行了突变筛查。然后，我们利用体外人错配修复（MMR）重组系统来评估继发于hMLH 1转染的CDK 2-AP 1表达的突变和变化的校正。我们还研究了CDK 2-AP 1调节在四种情况下的作用：（1）天然CDK 2-AP 1缺失，（2）内源性CDK 2-AP 1表达，（3）RNAi诱导的CDK 2-AP 1抑制和（4）诱导的CDK 2-AP 1过表达。3/12（25%）MSI CRC细胞系中发现CDK 2-AP 1基因3'端缺失T poly（T）8-突变，而在微卫星稳定的CRC细胞系中无突变（0/12）。有趣的是，当在体外人重组系统中诱导野生型MMR蛋白MLH 1时，del T poly（T）8突变被逆转，CDK 2-AP 1表达增加。RNAi介导的CDK 2-AP 1抑制与CDK 2-AP 1非缺陷CRC细胞系中细胞凋亡减少和细胞增殖增加相关。我们的结论是，CDK 2-AP 1基因的微卫星样序列突变在MSI CRC与CDK 2-AP 1表达下降。此外，人CRC中CDK 2-AP 1表达的调节改变细胞增殖和凋亡。
We have previously demon strated an association between microsatellite instability and decreased CDK2-AP1 (p12(DOC-1)) expression in human colorectal cancer (CRC) cell lines. In those same studies, induction of CDK2-AP1 expression promoted both cell cycle arrest and apoptosis. The goals of our present study were to better understand the mechanisms leading to reduced CDK2-AP1 expression in microsatellite unstable (MSI) CRC and to study further the effect of CDK2-AP1 modulation on cell proliferation and apoptosis utilizing RNA interference (RNAi) techniques. We used direct sequencing to screen for mutations of the poly(T) 8 microsatellite-like region in the 3' end of the CDK2-AP1 gene in 24 CRC cell lines. We then utilized an in vitro human mismatch repair (MMR) recombinant system to assess for correction of the mutation and changes in CDK2-AP1 expression secondary to hMLH1 transfection. We also investigated the effect of CDK2-AP1 modulation in four settings: (1) native CDK2-AP1 absence, (2) endogenous CDK2-AP1 expression, (3) RNAi-induced CDK2-AP1 inhibition and (4) induced CDK2-AP1 over expression. The mutation-del T poly (T)8-at the 3' end of the CDK2-AP1 gene was found in 3/12 (25%) of MSI CRC cell lines, but in none of the microsatellite stable samples (0/12). Interestingly, when wild-type MMR protein-MLH1-was induced in an in vitro human recombinant system, the del T poly (T) 8 mutation was reversed and CDK2-AP1 expression increased. RNAi-mediated CDK2-AP1 inhibition was associated with decreased apoptosis and increased cell proliferation in CDK2-AP1-non deficient CRC cell lines. We conclude that mutations in the microsatellite-like sequence of the CDK2-AP1 gene in MSI CRC are associated with decreased CDK2-AP1 expression. In addition, modulation of CDK2-AP1 expression in human CRC alters cell proliferation and apoptosis.