title: Triptolide induces cell-cycle arrest and apoptosis of human multiple myeloma cells in vitro via altering expression of histone demethylase LSD1 and JMJD2B.
abstract: OBJECTIVE
  To elucidate the relationship between triptolide-induced changes in histone methylation and its antitumor effect on human multiple myeloma (MM) cells in vitro.
  
  
  METHODS
  Human multiple myeloma cell line RPMI8226 was used. Apoptosis was evaluated using Annexin-V-FITC/PI-labeled flow cytometry, Hoechst 33258 staining, and transmission electron microscopy. Flow cytometry was used to detect the cell cycle distribution of the apoptotic cells. The presence of the LSD1, JMJD2B, H3K4me2, H3K9me2, and H3K36me2 proteins was verified by Western blot analysis. Semi-quantitative real-time PCR was performed to examine the expression of LSD1 and JMJD2B.
  
  
  RESULTS
  Triptolide (10-160 nmol/L) suppressed the proliferation of MM cells in a dose- and time-dependent manner with an IC(50) value of 99.2 ± 9.0 nmol/L at 24 h. Triptolide (50 nmol/L) induced G(0)/G(1) cell cycle arrest in MM cells. The agent (50-150 nmol/L) induced apoptosis of MM cells in a dose-dependent manner. The same concentrations of triptolide suppressed the expression of dimethylated H3K4, dimethylated H3K9 and dimethylated H3K36 by altering the expression of histone demethylase LSD1 and JMJD2B without affecting the expression of histone demethylase LSD1.
  
  
  CONCLUSIONS
  Triptolide potently inhibits the growth of MM cells via regulating the expression of histone demethylase LSD1 and JMJD2B, which lead to abnormal histone methylation.
authors: Department of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors: Lu
authors: L
authors: Wen
authors: Yan
authors: Y
authors: Chen
authors: Ling-lan
authors: LL
authors: Zeng
authors: Fei
authors: F
authors: Zhao
authors: Rui
authors: R
authors: Li
authors: Yuan
authors: Y
authors: Liu
authors: Chun
authors: C
authors: Zhang
mesh_terms: D000818:Animals; D018906:Antineoplastic Agents, Alkylating / Q000494:pharmacology / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects*; D059447:Cell Cycle Checkpoints / Q000187:drug effects*; D045744:Cell Line, Tumor / Q000187:drug effects / Q000648:ultrastructure; D049109:Cell Proliferation / Q000187:drug effects; D019175:DNA Methylation; D004224:Diterpenes / Q000494:pharmacology* / Q000627:therapeutic use*; D004852:Epoxy Compounds / Q000494:pharmacology / Q000627:therapeutic use; D056466:Histone Demethylases / Q000235:genetics / Q000378:metabolism*; D006657:Histones / Q000378:metabolism; D006801:Humans; D056484:Jumonji Domain-Containing Histone Demethylases / Q000235:genetics / Q000378:metabolism*; D008239:Lysine / Q000378:metabolism; D009101:Multiple Myeloma / Q000188:drug therapy* / Q000473:pathology; D010616:Phenanthrenes / Q000494:pharmacology* / Q000627:therapeutic use*
chemical_list: D018906:Antineoplastic Agents, Alkylating; D004224:Diterpenes; D004852:Epoxy Compounds; D006657:Histones; D010616:Phenanthrenes; C001899:triptolide; D056466:Histone Demethylases; D056484:Jumonji Domain-Containing Histone Demethylases; C523637:KDM4B protein, human; C495195:KDM1A protein, human; D008239:Lysine