title: PGE2-induced apoptotic cell death in K562 human leukaemia cells.
abstract: Prostaglandin-E2 (PGE2) is known to trigger suicidal death of nucleated cells (apoptosis) and enucleated erythrocytes (eryptosis). In erythrocytes PGE2 induced suicidal cell death involves activation of nonselective cation channels leading to Ca2+ entry followed by cell shrinkage and triggering of Ca2+ sensitive cell membrane scrambling with phosphatidylserine (PS) exposure at the cell surface. The present study was performed to explore whether PGE2 induces apoptosis of nucleated cells similarly through cation channel activation and to possibly disclose the molecular identity of the cation channels involved. To this end, Ca2+ activity was estimated from Fluo3 fluorescence, mitochondrial potential from DePsipher fluorescence, phosphatidylserine exposure from annexin binding, caspase activation from caspAce fluorescence, cell volume from FACS forward scatter, and DNA fragmentation utilizing a photometric enzyme immunoassay. Stimulation of K562 human leukaemia cells with PGE2 (50 microM) increased cytosolic Ca2+ activity, decreased forward scatter, depolarized the mitochondrial potential, increased annexin binding, led to caspase activation and resulted in DNA fragmentation. Gene silencing of the Ca2+-permeable transient receptor potential cation channel TRPC7 significantly blunted PGE2-induced triggering of PS exposure and DNA fragmentation. In conclusion, K562 cells express Ca2+-permeable TRPC7 channels, which are activated by PGE2 and participate in the triggering of apoptosis.
authors.affiliation: Department of Physiology, University of Tübingen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Föller
authors.forename: Ravi S
authors.initials: RS
authors.lastname: Kasinathan
authors.forename: Christophe
authors.initials: C
authors.lastname: Duranton
authors.forename: Thomas
authors.initials: T
authors.lastname: Wieder
authors.forename: Stephan M
authors.initials: SM
authors.lastname: Huber
authors.forename: Florian
authors.initials: F
authors.lastname: Lang
mesh_terms: D062565:Acid Sensing Ion Channels; D000584:Amiloride / Q000031:analogs & derivatives / Q000494:pharmacology; D017304:Annexin A5 / Q000187:drug effects / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology*; D002118:Calcium / Q000378:metabolism; D020169:Caspases / Q000187:drug effects / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D048429:Cell Size / Q000187:drug effects; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D053938:DNA Fragmentation; D015232:Dinoprostone / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D020868:Gene Silencing; D006801:Humans; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism; D020014:K562 Cells / Q000187:drug effects; D008564:Membrane Potentials / Q000187:drug effects; D008565:Membrane Proteins / Q000187:drug effects / Q000235:genetics; D008928:Mitochondria / Q000187:drug effects; D009419:Nerve Tissue Proteins / Q000187:drug effects / Q000235:genetics; D010718:Phosphatidylserines / Q000378:metabolism; D015222:Sodium Channels / Q000187:drug effects / Q000235:genetics; D050052:TRPC Cation Channels / Q000187:drug effects / Q000235:genetics
chemical_list: D062565:Acid Sensing Ion Channels; D017304:Annexin A5; D007473:Ion Channels; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D010718:Phosphatidylserines; D015222:Sodium Channels; D050052:TRPC Cation Channels; C498501:TRPC7 protein, human; D000584:Amiloride; D020169:Caspases; D015232:Dinoprostone; D002118:Calcium; C039614:ethylisopropylamiloride