甲基化转移酶3对食管癌细胞增殖、迁移及谷氨酰胺代谢的影响

Effect of methyltransferase like⁃3 on proliferation,migration and glutamine metabolism of esophageal cancer cells

目的探讨甲基化转移酶3(methyltransferase like-3,METTL3)在食管癌中的表达及其对细胞增殖、凋亡、迁移和谷氨酰胺代谢的影响。方法采用qRT-PCR、Western blot和免疫组化法检测食管癌组织及其癌旁组织中METTL3基因的表达;CCK8试验、克隆形成试验、划痕试验和Transwell试验检测METTL3抑制剂STM2457对人食管鳞状癌细胞系Eca109和KYSE150增殖及迁移的影响;流式细胞术、TUNEL染色试验检测其对细胞周期及凋亡的影响;TMT/iTRAQ定量蛋白质组法分析其对下游相关信号通路的影响;谷氨酰胺和谷氨酸检测试验及Western blot法分析其对食管癌细胞谷氨酰胺代谢的影响。结果METTL3在食管癌组织中的表达显著上调(t=5.024,P<0.0001)。STM2457抑制Eca109和KYSE150细胞的METTL3表达后,显著抑制了细胞的增殖及迁移能力,细胞周期在G0/G1期发生阻滞,细胞凋亡率增加,同时降低了谷氨酰胺摄取量和谷氨酸生成量,并下调了谷氨酰胺代谢相关蛋白丙氨酸-丝氨酸-半胱氨酸转运载体2(alanine-serine-cysteine transporter 2,ASCT2)、谷氨酰胺酶(glutaminase,GLS)和谷氨酸脱氢酶1(glutamate dehydrogenase 1,GLUD1)的表达。METTL3敲低后,Eca109和KYSE150细胞中谷氨酰胺摄取量和谷氨酸生成量显著降低(谷氨酰胺摄取量:t为24.52~41.01,P均<0.01;谷氨酸生成量:t为8.431~11.83,P均<0.01);METTL3过表达后,Eca109和KYSE150细胞中谷氨酰胺摄取量和谷氨酸生成量显著升高(谷氨酰胺摄取量:t分别为5.803和56.13,P均<0.01;谷氨酸生成量:t分别为11.06和4.695;P均<0.01)。METTL3敲低后,Eca109和KYSE150细胞中谷氨酰胺代谢相关蛋白ASCT2、GLS和GLUD1表达水平显著下调,而METTL3过表达后,ASCT2、GLS和GLUD1蛋白表达水平显著上调。结论METTL3在食管癌中高表达,并可能通过介导食管癌细胞谷氨酰胺代谢促进细胞增殖。

Objective To investigate the expression of methyltransferase like-3(METTL3)in esophageal cancer tissues and its effects on the proliferation,migration,apoptosis and glutamine metabolism of cells.Methods The expression of METTL3 in esophageal cancer and paraneoplastic tissues was detected by qRT-PCR,Western blot and Immunohistochemistry.The effects of METTL3 inhibitor STM2457 on cell proliferation and migration of human esophageal squamous carcinoma cell lines Eca109 and KYSE150 were detected by CCK8,cloning assay,scratch test and Transwell assay.The effects on cell cycle and cell apoptosis were measured by flow cytometry and TUNEL experiment.TMT/iTRAQ quantitative proteomics experiment was used to identify the effects on downstream related signaling pathways.Glutamine assay,glutamate assay and Western blot were used to analyze the effect on glutamine metabolism in esophageal cancer cells.Results METTL3 gene expression was significantly upregulated in esophageal cancer tissues(t=5.024,P<0.0001).STM2457 inhibited METTL3 expression in Eca109 and KYSE150 cells,significantly inhibited the cell proliferation and migration,blocked the cell cycle in G0/G1 phase,increased the cell apoptosis,decreased the glutamine uptake and glutamate production,and down-regulated the expression of glutamine-related proteins alanine-serine-cysteine transporter 2(ASCT2),glutaminase(GLS)and glutamate dehydrogenase 1(GLUD1).The glutamine uptake and glutamate production in Eca109 and KYSE150 cells decreased significantly after METTL3 knockdown(glutamine uptake:t=24.52-41.01,each P<0.01;glutamate production:t=8.431-11.83,each P<0.01);After METTL3 overexpression,the glutamine uptake and glutamate production in Eca109 and KYSE150 cells increased significantly(glutamine uptake:t=5.803 and 56.13,respectively,each P<0.01;glutamate production:t=11.06 and 4.695,respectively,each P<0.01).After METTL3 knockdown,the expression levels of glutamine metabolism related proteins ASCT2,GLS and GLUD1 in Eca109 and KYSE150 cells were significantly down-regulated,while after METTL3 overexpression,the expression levels of ASCT2,GLS and GLUD1 were significantly up-regulated.Conclusion METTL3 is highly expressed in esophageal cancer and may promote cell proliferation by mediating glutamine metabolism in esophageal cancer cells.