谷氨酰胺分解代谢促进鼻咽癌自噬和放疗抵抗性

Glutamine catabolism promotes autophagy and radioresistance in nasopharyngeal carcinoma

目的研究谷氨酰胺(Gln)代谢与鼻咽癌放疗抵抗的关系及作用机制。方法采用慢病毒感染技术建立肾型谷氨酰胺酶(GLS1)敲低的人鼻咽癌细胞系CNE1、6-10B及对照细胞系,脂质体转染技术建立GLS1过表达的人鼻咽癌细胞系CNE2及对照细胞系;采用谷氨酰胺酶抑制剂BPTES抑制GLS1的活性;采用Gln/Glu及Glu检测试剂盒检测细胞Gln代谢情况;体外放射克隆形成实验及流式检测细胞凋亡实验检测Gln代谢改变对放疗敏感性的影响;采用Western blot检测Gln代谢改变对自噬相关蛋白的表达;质粒转染LC3-EGFP后观察自噬荧光斑点。结果 Gln分解代谢降低后,体外放射克隆形成能力降低,细胞凋亡增加及细胞自噬水平降低;而分解代谢增加后,体外放射克隆形成能力增强,细胞凋亡降低及细胞自噬水平增加。结论 Gln分解代谢增强,激活鼻咽癌细胞自噬,增加鼻咽癌的放疗抵抗性。

Objective To study the relationship between glutamine metabolism and radiotherapy resistance in nasopharyngeal carcinoma （NPC）. Methods The glutaminase 1 （ GLS1 ） knockout CNE1, 6-10B cell lines and the control cell lines were established by lentivirus transfection technology. The CNE2 cell lines with GLS1 overexpression and control cell lines were established by liposome transfection technology. BPTES, one of Glutamine enzyme inhibitors, was used to inhibit the activity of GLS1. Glutamine/Glutamate（Gln/Glu） and Glu kits were used to detect glutamine metabolism in NPC cells; in vitro radiation clone formation experiment and flow cytometre mediated apoptosis assay were adopted to detect the effects of glutamine metabolism modulation on NPC radiosensitivity. Western blot and autophagie puncta monitor assay were carried out to detect the effects of glutamine metabolism modulation on autophagy status in NPC cells. Results Inhibiting the glutamine metabolism led to decreased clone formation, increased apoptotie rates, and decreased autophagic level in NPC cells; while activating the glutamine metabolism led to increased clone formation, decreased apoptotic rates and increased autophagic level in NPC cells. Conclusions The reduction of glutamine metabolism inhibits autophagy and increases radio sensitivity of NPC.