title: Increased 8-hydroxydeoxyguanosine in high-grade gliomas is associated with activation of autophagy.
abstract: OBJECTIVE
  To understand the interaction between oxidative stress and autophagy in gliomas of different grades.
  
  
  METHODS
  In the present study, we analyzed levels of oxidative stress in 45 human glioma tumors, using the DNA oxidation marker 8-hydroxydeoxyguanosine (8-OHdG). In addition, we determined activation of autophagy in gliomas samples by assessing expression of microtubule-associated protein 1 light chain-3B (LC3B). To confirm our in vivo findings, in vitro studies using U87 cells were conducted.
  
  
  RESULTS
  It was determined that the grade of gliomas, that is, different malignant degrees according to WHO classification, significantly affected level of 8-OHdG. High levels of 8-OHdG were present in high-grade gliomas. This trend was significant in male patients and in young adult patients (<50 years old). Further study showed increased expression of LC3B in high-grade gliomas. In addition, levels of 8-OHdG and expression of LC3B were positively correlated. Reducing autophagic activity by 3-methyladenine resulted in significantly increased intracellular reactive oxygen species (ROS) in U87 cells.
  
  
  CONCLUSIONS
  Our study provides evidence that high levels of oxidative stress in high-grade gliomas are associated with autophagy activation that may play a protective role promoting the survival of high-grade gliomas under severe oxidative stress.
authors.affiliation: 1Department of Neurosurgery, the First Affiliated Hospital of Medical College of Xi'an Jiaotong University, Xi'an, Shaanxi Province, P.R. China.
authors.forename: Minxue
authors.initials: M
authors.lastname: Lian
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Zhang
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.forename: Hao
authors.initials: H
authors.lastname: Liu
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.forename: Shiwen
authors.initials: S
authors.lastname: Guo
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D000328:Adult; D000368:Aged; D001343:Autophagy / Q000502:physiology; D001932:Brain Neoplasms / Q000378:metabolism* / Q000473:pathology*; D045744:Cell Line, Tumor; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000096:biosynthesis; D005260:Female; D005910:Glioma / Q000378:metabolism* / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress / Q000502:physiology; D055815:Young Adult
chemical_list: D000080242:8-Hydroxy-2'-Deoxyguanosine; D003849:Deoxyguanosine
keywords: WHO grading; gliomas; autophagy; oxidative stress