DFMO通过Fas/FasL通路诱导人肺癌细胞凋亡的研究

Apoptotic Induction of Human Lung Carcinoma A549 Cells by DFMO through Fas/FasL Pathway

背景与目的:Fas/FasL系统是细胞凋亡的重要通路。为了解Fas/FasL系统在肿瘤多胺生物合成抑制导致恶性表型逆转中的作用,本研究拟探讨多胺生物合成抑制剂α-二氟甲基鸟氨酸(α-difluoromethylornithine,DFMO)对人肺癌A549细胞生长、凋亡的影响及其与人肺癌相关抗原、rasP21蛋白及Fas/FasL表达的相关性。方法:用MTT法观察细胞生长,流式细胞仪分析细胞周期,DNAladder电泳法观察细胞凋亡,SP免疫组化法及RT-PCR法检测细胞蛋白及基因表达。结果:DFMO可抑制A549细胞生长并诱导凋亡,使G1期细胞增多(61.0±2.08)%,S期细胞减少(21.2±0.88)%,出现DNAladder;同时下调A549细胞人肺癌相关抗原及rasP21蛋白表达,上调Fas基因mRNA及蛋白表达。结论:DFMO通过Fas/FasL通路诱导肺癌A549细胞的凋亡,并可能与人肺癌相关抗原及rasP21蛋白表达调控有关。

BACKGROUND &OBJECTIVE: Fas/FasL pathway play an important role in cell apoptosis. To investigate the role of Fas/FasL system in polyamine biosyth esis inhibition and malignant phenotype reversion of carcinoma cells, we examine d the effect of DFMO (α-difluoromethylornithine), an inhibitor of polyamine bi osynthesis, on cell growth and apoptosis of A549 cells, and their association wi th human lung carcinoma-associated antigen, ras P21 protein, and Fas/FasL. METH ODS: MTT assay,flow cytometry,and DNA fragmentation analysis were used to determ ine cell growth and apoptosis,respectively.The gene and protein expression were determined by reverse transcription polymerase chain reaction (RT-PCR) and immu nohistochemical staining, respectively. RESULTS: DFMO could inhibit the growth o f A549 cells and induce their apoptosis, meanwhile the cells in G1 phase were in creased with (61.0±2.08)%, the cells in S phase were decreased with (21.2±0.8 8)%, and DNA ladder were observed. Simultaneously, the expression of human lung carcinoma-associated antigen and ras P21 protein were downregulated, but Fas m RNA and protein expression were upregulated. CONCLUSION: DFMO induce apoptosis o f human lung carcinoma A549 cells through Fas/FasL pathway. It might be correlat ed with the expression of human lung carcinoma-associated antigen and ras P21 p rotein.