诺帝对CasKi细胞增殖及中心体Aurora-A和γ-tubulin基因表达的影响

目的 探讨诺帝对CasKi细胞增殖、细胞周期及中心体Aurora-A、γ-tubulin和P53蛋白表达的影响及其作用机制.方法 用不同浓度的诺帝处理CasKi细胞,MTT法检测细胞增殖活力,流式细胞术分析细胞周期,间接免疫荧光检测中心体的变化,RT-PCR检测细胞Aurora-A基因mRNA的表达,Western blot法检测细胞γ-tubulin、Aurora-A和P53蛋白的表达.结果 诺帝能明显抑制CasKi细胞增殖,阻滞细胞周期于G0/G1期,且呈明显的剂量和时间依赖性;细胞中心体内γ-tubulin荧光信号明显减弱,Aurora-A基因mRNA的表达量及γ-tubulin和Aurora-A蛋白的表达量明显下降,而P53蛋白的表达量明显升高,且呈剂量依赖性.结论 诺帝可能通过下调Aurora-A,上调P53,发挥其抑制CasKi细胞增殖、阻滞细胞周期,并阻止中心体扩增,限制细胞无序增殖的作用.

Background and objectiveMaintenance of genomic integrity is essential to ensure normal organismal development and to prevent diseases such as cancer. PR-Set7 (also known as Set8) is a cell cycle regulated enzyme that catalyses monomethylation of histone 4 at Lys20 (H4K20me1) to promote chromosome condensation and prevent DNA damage. Recent studies show that CRL4CDT2-mediated ubiquitylation of PR-Set7 leads to its degradation during S phase and atfer DNA damage. hTis might occur to ensure appropriate changes in chromosome structure during the cell cycle or to preserve genome integrity atfer DNA damage.Methods We developed a new model of lung tumor development in mice harboring a conditionally expressed allele of Cul4A. We have therefore used a mouse model to demonstrate for the ifrst time that Cul4A is oncogenicin vivo. With this model, staining of PR-Set7 in the preneoplastic and tumor lesions in AdenoCre-induced mouse lungs was performed. Meanwhile we identiifed higher protein level changes of γ-tubulin and pericentrin by IHC.Results hTe level of PR-Set7 down-regulated in the preneoplastic and adenocarcinomous lesions following over-expression of Cul4A. We also identiifed higher levels of the proteins pericentrin and γ-tubulin in Cul4A mouse lungs induced by AdenoCre.Conclusion PR-Set7 is a direct target of Cul4A for degradation and involved in the formation of lung tumors in the conditional Cul4A transgenic mouse model.