title: 16-hydroxycleroda-3,13-dien-15,16-olide regulates the expression of histone-modifying enzymes PRC2 complex and induces apoptosis in CML K562 cells.
abstract: OBJECTIVE
  Histone modifications play central epigenetic roles in regulating the entire genome of the cell and cell proliferation. Herein, we investigated the effects of the natural compound, 16-hydroxycleroda-3,13-dien-15,16-olide (PL3), on the expressions of histone-modifying enzymes, and examined how it induces apoptosis in leukemia K562 cells.
  
  
  METHODS
  Cell proliferation was determined by an MTT assay, and histone-modifying enzyme gene expressions were investigated by a quantitative real-time PCR. Protein expressions were analyzed by a Western blot analysis. The histone H3K27 distribution was observed with immunofluorescence staining. To verify polycomb repressive complex 2 (PRC2) complex downstream gene expressions, a gene-expression array was performed to determine gene regulations.
  
  
  RESULTS
  PL3 induced apoptosis and modulated many histone-modifying enzymes, especially the two PRC2 components, enhancer of zeste homolog 2 (EZH2) and suppressor of zeste 12 homolog (Suz12). Genes repressed by PRC2 were shown to be reactivated by PL3. Of these, 10 genes targeted by the PRC2 complex were identified, and expressions of 10 pro-/antiapoptotic genes were significantly regulated; these effects may have contributed to PL3-induced apoptosis in K562 cells. Regulation of other histone-modifying enzymes, including Aurora B, may also be involved in cell-cycle regulation.
  
  
  CONCLUSIONS
  Our data suggest that the induction of apoptosis by PL3 might partly occur through both a reduction in PRC2-mediated gene silencing and the reactivation of downstream tumor suppressor gene expressions. PL3 acts as a novel small-molecule histone modulator, which can potentially contribute to cancer chemotherapy singly or as a combined medication.
authors: Graduate Institute of Natural Products, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors: Yi-Hsiung
authors: YH
authors: Lin
authors: Chien-Chih
authors: CC
authors: Lee
authors: Fang-Rong
authors: FR
authors: Chang
authors: Wen-Hsin
authors: WH
authors: Chang
authors: Yang-Chang
authors: YC
authors: Wu
authors: Jan-Gowth
authors: JG
authors: Chang
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D002352:Carrier Proteins / Q000096:biosynthesis / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000187:drug effects; D004224:Diterpenes / Q000494:pharmacology*; D000071221:Enhancer of Zeste Homolog 2 Protein; D005434:Flow Cytometry; D015870:Gene Expression / Q000187:drug effects; D006657:Histones / Q000378:metabolism; D006801:Humans; D020014:K562 Cells / Q000187:drug effects* / Q000378:metabolism; D008856:Microscopy, Fluorescence; D009363:Neoplasm Proteins; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000187:drug effects; D020411:Oligonucleotide Array Sequence Analysis; D063151:Polycomb Repressive Complex 2; D063146:Polycomb-Group Proteins; D060888:Real-Time Polymerase Chain Reaction; D012097:Repressor Proteins / Q000096:biosynthesis* / Q000187:drug effects; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000096:biosynthesis / Q000187:drug effects
chemical_list: D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D004224:Diterpenes; D006657:Histones; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D063146:Polycomb-Group Proteins; D012097:Repressor Proteins; C430461:SUZ12 protein, human; D014157:Transcription Factors; C072581:16-hydroxycleroda-3,13(14)-dien-15,16-olide; C498409:EZH2 protein, human; D000071221:Enhancer of Zeste Homolog 2 Protein; D063151:Polycomb Repressive Complex 2