title: Inhibitory effect of DNA topoisomerase inhibitor isoliquiritigenin on the growth of glioma cells.
abstract: OBJECTIVE
  To investigate the effect of isoliquiritigenin on the activity of DNA topoisomerase (TOP I) and its inhibitory effect on the growth of U87 glioma cells.
  
  
  METHODS
  This study investigated the inhibitory effect of isoliquiritigenin on the growth of U87 glioma cells and its cytotoxicity by MTT method and determined the effect of isoliquiritigenin on TOP I activity by agarose gel electrophoresis. On this basis, we studied the interaction between isoliquiritigenin and TOP I and DNA. Finally, we further discussed the effect of isoliquiritigenin on the activity of Caspase 3, the apoptosis protein of U87 glioma cells.
  
  
  RESULTS
  Isoliquiritigenin could inhibit the growth of U87 glioma cells (half inhibitory concentration IC50: 0.221 mM) and is of low cytotoxicity to normal cells. Agarose gel electrophoresis showed that isoliquiritigenin had significant inhibitory effect on TOP I activity. Molecular simulation results indicated that isoliquiritigenin took priority of binding to the active center of TOP I, and formed hydrogen bonds with the catalytic site Try723. Finally, Caspase 3 activity detection results suggested that isoliquiritigenin could significantly increase the activity of Caspase 3 (P < 0.05).
  
  
  CONCLUSIONS
  Isoliquiritigenin had a reversible inhibitory effect on TOP I activity, reduced the rate of single strand DNA unwinding in tumor cells, and thus played an important role in inducing the apoptosis of U87 glioma cells.
authors.affiliation: Department of Neurosurgery, The First Affiliated Hospital of Xinxiang Medical University Weihui 453100, Henan Province, China.
authors.forename: Shupeng
authors.initials: S
authors.lastname: Zhao
authors.affiliation: Department of Neurosurgery, The First Affiliated Hospital of Xinxiang Medical University Weihui 453100, Henan Province, China.
authors.forename: Haigang
authors.initials: H
authors.lastname: Chang
authors.affiliation: Department of Neurosurgery, The First Affiliated Hospital of Xinxiang Medical University Weihui 453100, Henan Province, China.
authors.forename: Pengju
authors.initials: P
authors.lastname: Ma
authors.affiliation: Department of Neurosurgery, The First Affiliated Hospital of Xinxiang Medical University Weihui 453100, Henan Province, China.
authors.forename: Guojun
authors.initials: G
authors.lastname: Gao
authors.affiliation: Department of Oncology, The First Affiliated Hospital of Xinxiang Medical University Weihui 453100, Henan Province, China.
authors.forename: Cailing
authors.initials: C
authors.lastname: Jin
authors.affiliation: Department of Neurosurgery, The First Affiliated Hospital of Xinxiang Medical University Weihui 453100, Henan Province, China.
authors.forename: Xinli
authors.initials: X
authors.lastname: Zhao
authors.affiliation: Department of Neurosurgery, The First Affiliated Hospital of Xinxiang Medical University Weihui 453100, Henan Province, China.
authors.forename: Wenke
authors.initials: W
authors.lastname: Zhou
authors.affiliation: Department of Neurosurgery, The First Affiliated Hospital of Xinxiang Medical University Weihui 453100, Henan Province, China.
authors.forename: Baozhe
authors.initials: B
authors.lastname: Jin
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D001932:Brain Neoplasms / Q000473:pathology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D047188:Chalcones / Q000494:pharmacology*; D004587:Electrophoresis, Agar Gel; D005910:Glioma / Q000473:pathology*; D006801:Humans; D020128:Inhibitory Concentration 50; D062105:Molecular Docking Simulation; D059003:Topoisomerase Inhibitors / Q000494:pharmacology*
chemical_list: D047188:Chalcones; D059003:Topoisomerase Inhibitors; C040920:isoliquiritigenin
keywords: DNA topoisomerase; Isoliquiritigenin; U87 glioma cell; apoptosis; inhibitory effect