title: Cytotoxicity, apoptosis induction, and mitotic arrest by a novel podophyllotoxin glucoside, 4DPG, in tumor cells.
abstract: OBJECTIVE
  To define the in vitro cytotoxic activities of 4-demethyl-picropodophyllotoxin 7'-O-beta-D-glucopyranoside (4DPG), a new podophyllotoxin glucoside.
  
  
  METHODS
  Antiproliferation activity was measured in several tumor cell lines by using the microculture tetrazolium MTT assays. Cell cycle distribution was analyzed using flow cytometry and mitosis index assays. Furthermore, transmission electron microscopy, TUNEL, DNA agarose electrophoresis, and activated caspase-3 were used to analyze the induction of apoptotic cell death. Moreover, intracellular changes in the cytoskeleton were detected using immunocytochemistry.
  
  
  RESULTS
  4DPG effectively inhibited the proliferation of cancer cells (HeLa, CNE, SH-SY5Y, and K562 cell lines). For the K562 cell line, the antiproliferation effect of 4DPG was much more potent than that of etoposide (IC50 value: 7.79 x 10(-9) mol/L for 4DPG vs 2.23 x 10(-5) mol/L for etoposide). Further, 4DPG blocked the cell cycle in the mitotic phase. The induction of apoptosis and elevated levels of activated caspase-3 were confirmed in cells treated with 4DPG. The microtubule skeleton of HeLa cells was disrupted immediately after treatment with 4DPG.
  
  
  CONCLUSIONS
  The cytotoxicity of 4DPG is due to its inhibition of the microtubule assembly of cancer cells at a low concentration, thus inducing apoptosis. These properties qualify 4DPG to be a potential antitumor drug.
authors.affiliation: College of Life Sciences, Beijing Normal University, Beijing 100875, China.
authors.forename: Yi-lin
authors.initials: YL
authors.lastname: Qi
authors.forename: Fan
authors.initials: F
authors.lastname: Liao
authors.forename: Chang-qi
authors.initials: CQ
authors.lastname: Zhao
authors.forename: Yong-da
authors.initials: YD
authors.lastname: Lin
authors.forename: Ming-xue
authors.initials: MX
authors.lastname: Zuo
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects*; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D049109:Cell Proliferation / Q000187:drug effects*; D053938:DNA Fragmentation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D005960:Glucosides / Q000737:chemistry / Q000494:pharmacology*; D006367:HeLa Cells; D006801:Humans; D020014:K562 Cells; D046529:Microscopy, Electron, Transmission; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism; D015394:Molecular Structure; D011034:Podophyllotoxin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D011108:Polymers / Q000378:metabolism; D013997:Time Factors
chemical_list: C440054:4-demethyl-picropodophyllotoxin 7'-O-glucopyranoside; D005960:Glucosides; D011108:Polymers; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; D011034:Podophyllotoxin