title: Knock-down of glutaminase 2 expression decreases glutathione, NADH, and sensitizes cervical cancer to ionizing radiation.
abstract: Phosphate-activated mitochondrial glutaminase (GLS2) is suggested to be linked with elevated glutamine metabolism. It plays an important role in catalyzing the hydrolysis of glutamine to glutamate. The present study was to investigate the potent effect of GLS2 on radioresistance of cervical carcinoma. GLS2 was examined in 144 cases of human cervical cancer specimens (58 radioresistant specimens, 86 radiosensitive specimens) and 15 adjacent normal cervical specimens with immunohistochemistry. HeLa cells were treated with a cumulative dose of 50Gy X-rays, over 6months, yielding the resistant sub-line HeLaR. The expressions of GLS2 were measured by Western blot. Radioresistance was tested by colony survival assay. Apoptosis was determined by flow cytometry. The levels of glutathione (GSH), reactive oxygen species (ROS), NAD(+)/NADH ratio and NADP(+)/NADPH ratio were detected by quantization assay kit. Xenografts were used to confirm the effect of GLS2 on radioresistance in vivo. The expressions of GLS2 were significantly enhanced in tumor tissues of radioresistant patients compared with that in radiosensitive patients. In vitro, the radioresistant cell line HeLaR exhibited significantly increased GLS2 levels than its parental cell line HeLa. GLS2 silenced radioresistant cell HeLaR shows substantially enhanced radiosensitivity with lower colony survival and higher apoptosis in response to radiation. In vivo, xenografts with GLS2 silenced HeLaR were more sensitive to radiation. At the molecular level, knock-down of GLS2 increased the intracellular ROS levels of HeLaR exposed to irradiation by decreasing the productions of antioxidant GSH, NADH and NADPH. GLS2 may have an important role in radioresistance in cervical cancer patients.
authors: Department of Oncology, Southwest Hospital, the Third Military Medical University, Chongqing 400038, PR China; Radiation Oncology Center, Southwest Hospital, the Third Military Medical University, Chongqing 400038, PR China.
authors: Lisha
authors: L
authors: Xiang
authors: Department of Oncology, Southwest Hospital, the Third Military Medical University, Chongqing 400038, PR China; Radiation Oncology Center, Southwest Hospital, the Third Military Medical University, Chongqing 400038, PR China.
authors: Ganfeng
authors: G
authors: Xie
authors: Radiation Oncology Center, Southwest Hospital, the Third Military Medical University, Chongqing 400038, PR China.
authors: Chen
authors: C
authors: Liu
authors: Department of Oncology, Southwest Hospital, the Third Military Medical University, Chongqing 400038, PR China.
authors: Jie
authors: J
authors: Zhou
authors: Department of Oncology, Southwest Hospital, the Third Military Medical University, Chongqing 400038, PR China.
authors: Jianfang
authors: J
authors: Chen
authors: Department of Oncology, Southwest Hospital, the Third Military Medical University, Chongqing 400038, PR China.
authors: Songtao
authors: S
authors: Yu
authors: Department of Oncology, Southwest Hospital, the Third Military Medical University, Chongqing 400038, PR China; Southwest Cancer Center, Southwest Hospital, the Third Military Medical University, Chongqing 400038, PR China.
authors: Jianjun
authors: J
authors: Li
authors: Radiation Oncology Center, Southwest Hospital, the Third Military Medical University, Chongqing 400038, PR China.
authors: Xueli
authors: X
authors: Pang
authors: Department of Biology, Georgia State University, Atlanta, GA 30303, USA.
authors: Hang
authors: H
authors: Shi
authors: Department of Oncology, Southwest Hospital, the Third Military Medical University, Chongqing 400038, PR China; Radiation Oncology Center, Southwest Hospital, the Third Military Medical University, Chongqing 400038, PR China; Southwest Cancer Center, Southwest Hospital, the Third Military Medical University, Chongqing 400038, PR China. Electronic address: lianghoujie@sina.com.
authors: Houjie
authors: H
authors: Liang
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D045744:Cell Line, Tumor; D005260:Female; D055785:Gene Knockdown Techniques; D005972:Glutaminase / Q000378:metabolism*; D005978:Glutathione / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D007150:Immunohistochemistry; D042541:Intracellular Space / Q000378:metabolism / Q000528:radiation effects; D051379:Mice; D008819:Mice, Nude; D008875:Middle Aged; D009243:NAD / Q000378:metabolism*; D011836:Radiation Tolerance / Q000528:radiation effects; D011839:Radiation, Ionizing; D017382:Reactive Oxygen Species / Q000378:metabolism; D002583:Uterine Cervical Neoplasms / Q000201:enzymology / Q000473:pathology / Q000532:radiotherapy*; D023041:Xenograft Model Antitumor Assays
chemical_list: D000975:Antioxidants; D017382:Reactive Oxygen Species; D009243:NAD; C586504:GLS2 protein, human; D005972:Glutaminase; D005978:Glutathione
keywords: Cervical cancer; Glutathione; Phosphate-activated mitochondrial glutaminase; Radioresistance