title: Carvacrol-induced [Ca2+]i rise and apoptosis in human glioblastoma cells.
abstract: OBJECTIVE
  This study examined whether the essential oil component carvacrol altered cytosolic free Ca(2+) level ([Ca(2+)](i)) and viability in human glioblastoma cells.
  
  
  METHODS
  The Ca(2+)-sensitive fluorescent dye fura-2 was applied to measure [Ca(2+)](i). Cell viability was measured by detecting reagent WST-1. Apoptosis and reactive oxygen species (ROS) were detected by flow cytometry.
  
  
  RESULTS
  Carvacrol at concentrations of 400-1000 μM induced a [Ca(2+)](i) rise in a concentration-dependent fashion. The response was decreased partially by removal of extracellular Ca(2+). Carvacrol-induced Ca(2+) signal was not altered by nifedipine, econazole, SK&F96365, and protein kinase C activator phorbol myristate acetate (PMA), but was inhibited by the protein kinase C inhibitor GF109203X. When extracellular Ca(2+) was removed, incubation with the endoplasmic reticulum Ca(2+) pump inhibitor thapsigargin or 2,5-di-tert-butylhydroquinone (BHQ) abolished carvacrol-induced [Ca(2+)](i) rise. Incubation with carvacrol also abolished thapsigargin or BHQ-induced [Ca(2+)](i) rise. Inhibition of phospholipase C with U73122 abolished carvacrol-induced [Ca(2+)](i) rise. At concentrations of 200-800 μM, carvacrol killed cells in a concentration-dependent manner. This cytotoxic effect was not changed by chelating cytosolic Ca(2+) with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N--tetraacetic acid/acetoxy methyl (BAPTA/AM). Annexin V/propidium iodide staining data suggest that carvacrol (200, 400 and 600 μM) induced apoptosis in a concentration-dependent manner. At concentrations of 200, 400 and 600 μM, carvacrol induced production of ROS.
  
  
  CONCLUSIONS
  In human glioblastoma cells, carvacrol induced a [Ca(2+)](i) rise by inducing phospholipase C-dependent Ca(2+) release from the endoplasmic reticulum and Ca(2+) entry via protein kinase C-sensitive, non store-operated Ca(2+) channels. Carvacrol induced cell death that might involve ROS-mediated apoptosis.
authors.affiliation: Department of Biological Sciences, National Sun Yat-Sen University, Kaohsiung 804, Taiwan.
authors.forename: Wei Zhe
authors.initials: WZ
authors.lastname: Liang
authors.forename: Cheng Hsien
authors.initials: CH
authors.lastname: Lu
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects; D053148:Caspase 3 / Q000378:metabolism; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D000081007:Cymenes; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D005909:Glioblastoma / Q000188:drug therapy / Q000378:metabolism; D006801:Humans; D008345:Manganese / Q000378:metabolism; D039821:Monoterpenes / Q000494:pharmacology*; D009822:Oils, Volatile / Q000737:chemistry; D031341:Origanum / Q000737:chemistry; D017382:Reactive Oxygen Species / Q000378:metabolism; D010738:Type C Phospholipases / Q000378:metabolism
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D000081007:Cymenes; D039821:Monoterpenes; D009822:Oils, Volatile; D017382:Reactive Oxygen Species; D008345:Manganese; C073316:carvacrol; D010738:Type C Phospholipases; D053148:Caspase 3; D002118:Calcium