摘要
目的:探讨化学预防药物Sulfone是否通过转录调节XAF1的表达诱导结肠癌细胞凋亡。方法:采用Hoechst 33258染色法检测人结肠癌细胞株HCT116(p53野生型)和SW480(p53突变型)经Sulfone处理后的细胞凋亡率。运用Western印迹法检测上述细胞经Sulfone处理前后XAF1、磷酸化ERK1/2(p-ERK1/2)和ERK1/2总蛋白质的表达量变化。通过双重荧光素酶报告基因检测Sulfone对XAF1启动子转录活性的调节作用。结果:Sulfone能诱导HCT116和SW480细胞凋亡,其效应随剂量的增加和时程的延长而更明显。Sulfone能有效抑制上述两种细胞中ERK1/2蛋白的磷酸化(抑制率分别为74%和57%,P<0.05),但上调XAF1蛋白的表达(2.2倍和3.1倍,P<0.05)。经Sulfone处理后,XAF1启动子的转录活性在HCT116和SW480细胞分别提高了3.3倍(P<0.01)和2.6倍(P<0.05)。结论:Sulfone通过抑制ERK途径,在转录水平显著上调XAF1的表达进而诱导细胞凋亡,且这种作用的强弱与肿瘤细胞的p53分型有关。
Objective To investigate the ettect ot 3ultone, a potent chemo-preventlve agent, on reducing apoptosls in colon cancer cells through transcriptional regulation of the expression of XAF1. Methods After Sulfone treatment, apoptosis was determined with Hoechst 33258 staining in human colon cancer cell lines, HCTll6 （wild-type p53） and SW480 （mutant p53）. The protein levels of phosphorylated-ERK1/2 （p-ERK1/2）, ERK1/2 and XAF1 were detected by Western blot. The transcription activities of core XAF1 promotor with and without Sulfone treatment were measured by dual luciferase reporter assay. Results Sulfone induced apoptosis in a time- and dose-dependent manner in both HCT116 and SW480 cells. The protein level of p-ERK1/2 decreased 74% in HCTll6 and 57% in SW480 cells, respectively, P〈 0.05. Conversely, the protein level of XAF1 was up-regulated 2.2-fold and 3.1-fold, P〈0.05. Furthermore, the transcriptional activity of the putative promotor of the XAF1 gene was increased 3.3-fold in HCTll6 cells （P〈0.01）and 2.6-fold in SW480 cells （P〈0.05） after Sulfone treatment. Conclusions Sulfone can up-regulate the expression of XAF1 by inhibition of the ERK pathway through transcriptional regulation which in turn leads to apoptosis in colon cancer cells. This effect is associated with different genotypes of p53 of cancer cells.
出处
《外科理论与实践》
2012年第5期459-462,共4页
Journal of Surgery Concepts & Practice
基金
国家自然科学基金(30872973)
上海市重点学科(外科学)开放课题(S30204-k03)
