title: Pipoxolan inhibits proliferation of HL-60 human leukaemia cancer cells by arresting the cell cycle at the G0/G1 phase.
abstract: 1. The aim of the present study was to investigate the molecular mechanisms by which pipoxolan exerts its inhibitory effects and apoptotic activity in human leukaemia HL-60 cells. 2. The effects of pipoxolan on the proliferation of HL-60 cells and on the distribution of cells within different phases of the cell cycle were investigated indirectly using a Trypan blue assay and a flow cytometer, respectively. The effects of pipoxolan on the apoptosis of HL-60 cells was investigated using DNA fragmentation and flow cytometer. The expression of factors affecting the cell cycle and apoptosis, including p53, p21, Bax, Bcl2, cytochrome c, caspase 3 and caspase 9, was examined by western blotting. 3. At 6.25 microg/mL, pipoxolan significantly induced apoptosis in human leukaemia HL-60 cells after 24 h exposure. In addition, HL-60 cells were arrested in the G(0)/G(1) phase via the induction of p53/p21 by pipoxolan. Apoptosis was associated with an increased Bax/Bcl-2 ratio, cytochrome c release, cleavage of procaspases-9 and -3 and hydrolysis of poly(ADP-ribose) polymerase. Intracellular reactive oxygen species (ROS) seem to play a key role in the pipoxolan-induced apoptosis, because high levels of ROS were produced early in the drug treatment. Apoptosis was significantly abrogated by the free radical scavenger N-acetylcysteine (NAC).
authors.affiliation: School of Pharmacy, China Medical University, 91, Hsueh-Shih Rd., Taichung, 404, Taiwan, Republic of China.
authors.forename: Ming-Jyh
authors.initials: MJ
authors.lastname: Sheu
authors.forename: Pei-Yu
authors.initials: PY
authors.lastname: Chou
authors.forename: Chin-Shiu
authors.initials: CS
authors.lastname: Huang
authors.forename: I-Chun
authors.initials: IC
authors.lastname: Tsai
authors.forename: Yi-Chung
authors.initials: YC
authors.lastname: Chien
authors.forename: Sung-Yuan
authors.initials: SY
authors.lastname: Lin
authors.forename: Huei-Yann
authors.initials: HY
authors.lastname: Tsai
authors.forename: Hsu-Chen
authors.initials: HC
authors.lastname: Cheng
authors.forename: Chieh-Hsi
authors.initials: CH
authors.lastname: Wu
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D053148:Caspase 3 / Q000378:metabolism; D018929:Cell Culture Techniques; D049109:Cell Proliferation / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D053938:DNA Fragmentation / Q000187:drug effects; D004148:Dioxolanes / Q000737:chemistry / Q000494:pharmacology*; D005434:Flow Cytometry; D016193:G1 Phase / Q000187:drug effects*; D018922:HL-60 Cells; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D015394:Molecular Structure; D017382:Reactive Oxygen Species / Q000378:metabolism; D016192:Resting Phase, Cell Cycle / Q000187:drug effects*
chemical_list: D000970:Antineoplastic Agents; D004148:Dioxolanes; D017382:Reactive Oxygen Species; C000121:pipoxolan; D053148:Caspase 3