EGCG通过抑制谷氨酰胺代谢通路抑制结直肠癌细胞的生长的实验研究

EGCG Inhibits the Growth of Colorectal Cancer Cells by Inhibiting Glutamine Metabolic Pathway

目的:探讨茶多酚中主要成分表没食子儿茶素没食子酸酯(EGCG)对结直肠癌DLD-1细胞的增殖影响及其与谷氨酰胺代谢通路的关系。方法:用CCK8试剂盒检测不同浓度EGCG对DLD-1细胞增殖的影响,并用Western blot方法检测凋亡蛋白的表达水平。进而分别用外源补充谷氨酰胺、添加谷氨酰胺酶抑制剂CB-839等方法探讨EGCG的作用机理与路径。结果:EGCG在一定程度上可以抑制结直肠癌DLD-1细胞的增殖并且引起该细胞凋亡,同时,外源补充谷氨酰胺可削弱EGCG的作用,而用谷氨酰胺酶抑制剂CB-839抑制谷氨酰胺的代谢,则加剧EGCG对DLD-1细胞的生长抑制作用。同时,实验发现EGCG可以使谷氨酰胺脱氢酶的活力下降。结论:EGCG可通过抑制细胞谷氨酰胺的代谢而诱导肿瘤细胞发生凋亡。

Object： Epigallocatechin gallate（EGCG）, the most abundant polyphenols in tea, has antitumor effects. In this research, we try to find the relationship between the role of EGCG in glutamine metabolism and the inhibitory effect of EGCG on cell proliferation. Methods： The cell counting kit-8 were used to determine the cell proliferation, the Western blot was used to check the protein levels of PARP and cleaved caspase 3; extraneous glutamine and CB-839（an inhibitor of glutaminase） were utilized to explore the role of EGCG in the converting process of glutamine to glutamate. Results： EGCG could inhibit the proliferation of DLD-1 cells and increase the levels of PARP and cleaved caspase 3. At the same time, supplementary glutamine could weaken the toxic effect of EGCG to DLD-1 cells, and glutaminase inhibitor CB-839 increased the toxic effect of EGCG. Additionally, EGCG could reduce the activity of glutamine dehydrogenase. Conclusions： This research suggested that the inhibition of cell proliferation by EGCG was associated with the inhibition of glutamine metabolism in DLD-1 cells.