β-胡萝卜素对食管癌细胞凋亡与Cav-1表达的影响*
Relationship between β-carotene inducing-apoptosis and Cav-1 expression in human esophageal squamous cancer cells

目的:观察β-胡萝卜素对食管癌细胞凋亡的影响,并分析食管癌细胞对β-胡萝卜素的敏感性与小窝蛋白-1(Cav-1)表达的关系。方法:采用Western blot法检测正常食管上皮细胞株Het-1A及食管癌细胞(TE1、EC1和Eca109)中Cav-1蛋白的表达; CCK-8法检测不同浓度(0、1、5、10、20、30、50 μmol/L)β-胡萝卜素处理食管癌细胞12、24、36、48、60、72 h后,对食管癌细胞增殖抑制的影响,筛选出β-胡萝卜素的最佳处理时间及浓度; 在筛选条件下处理食管癌细胞,采用Annexin V-FITC/PI双染法检测细胞凋亡率; qRT-PCR检测Cav-1 mRNA表达水平的变化; Western blot检测Cav-1蛋白表达水平的变化。结果:Cav-1蛋白在食管癌细胞中呈过表达(TE1＞Eca109＞EC1),而Het-1A细胞中无Cav-1表达。β-胡萝卜素对正常食管上皮细胞的增殖无抑制作用,而对食管癌细胞(TE1、EC1和Eca109)的增殖抑制作用具有时间和剂量依赖性,且食管癌细胞对β-胡萝卜素的敏感性与Cav-1的表达有关。分别采用30、50、50 μmol/L β-胡萝卜素处理48 h后,TE1、Eca109和EC1细胞凋亡率显著提高(P＜0.05),Cav-1 mRNA和蛋白质表达水平均明显下降。结论:β-胡萝卜素能够有效促进食管癌细胞凋亡,而对正常食管上皮细胞无毒性作用,且食管癌细胞对β-胡萝卜素的敏感性可能受到Cav-1的调节。
Aim: To observe the effect of β-carotene on cell apoptosis in esophageal cancer cells, and analyze the relationship between the sensitivity of esophageal cancer cells to β-carotene and the expression of caveolin-1(Cav-1).Methods: The expressions of Cav-1 protein in normal esophageal epithelial cell line Het-1A and three esophageal cancer cell lines(TE1,EC1,Eca109)were detected by Western blot; after treatment with different concentrations(0, 1, 5, 10, 20, 30 and 50 μmol/L)of β-carotene for 12, 24, 36, 48, 60 and 72 h, the proliferation rate of esophageal cancer cells was tested by CCK8 assay, and the optimal time and concentration of β-carotene were determined; then the cell apoptosis of esophageal cancer cells were detected by Annexin V-FITC/PI staining; the mRNA level of Cav-1 was determined by qRT-PCR, the expression level of Cav-1 protein was detected by Western blot.Results: Cav-1 was over-expressed in esophageal cancer cells(TE1＞Eca109＞EC1), and was undetectable in Het-1A. CCK-8 assay showed that β-carotene has no effect on Het-1A cells, but inhibited the proliferation of three esophageal cancer cell lines in a dose- and time-dependent manner. In addition, there were relation between the expression of Cav-1 and the sensitivity of esophageal cancer cells to β-carotene. The dose and treatment time of β-carotene when the cell proliferations were decreased nearly 50% were used in the following experiments. After treatment with β-carotene, TE1,EC1 and Eca109 cells had higher apoptosis rate than that of negative control group(P＜0.05), especially TE1. In addition, the mRNA and protein level of Cav-1 were both significantly down-regulated.Conclusion: β-carotene can effectively induce apoptosis in esophageal cancer cells, which is non-toxic to the normal esophageal epithelial cell. Moreover, the sensitivity of esophageal cancer cells to the β-carotene may be regulated by Cav-1