title: Lysophosphatidylserine stimulates leukemic cells but not normal leukocytes.
abstract: In this study, we observed that lysophosphatidylserine (LPS) stimulated intracellular calcium ([Ca(2+)](i)) increase in leukemic cells but not in normal human peripheral blood mononuclear cells. LPS also stimulated [Ca(2+)](i) increase in human leukemic THP-1 cells. LPS-stimulated [Ca(2+)](i) increase was inhibited by U-73122 but not by U-73343. LPS also stimulated inositol phosphates formation in THP-1 cells, suggesting that LPS stimulates calcium signaling via phospholipase C activation. Moreover, pertussis toxin (PTX) completely inhibited [Ca(2+)](i) increase by LPS, indicating the activation of PTX-sensitive G-proteins. We also found that LPS-induced [Ca(2+)](i) increase was completely inhibited by suramin, suggesting G-protein coupled receptor activation. Since LPS specifically stimulates PTX-sensitive G-proteins, phospholipase C-dependent [Ca(2+)](i) increase in leukemic cells but not normal peripheral blood leukocytes, LPS receptor may be associated with leukemia.
authors.affiliation: Medical Research Center for Cancer Molecular Therapy, College of Medicine, Dong-A University, Busan 602-714, Republic of Korea.
authors.forename: Kyoung Sun
authors.initials: KS
authors.lastname: Park
authors.forename: Ha Young
authors.initials: HY
authors.lastname: Lee
authors.forename: Mi-Kyoung
authors.initials: MK
authors.lastname: Kim
authors.forename: Eun Ha
authors.initials: EH
authors.lastname: Shin
authors.forename: Yoe-Sik
authors.initials: YS
authors.lastname: Bae
mesh_terms: D002118:Calcium / Q000378:metabolism*; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006801:Humans; D007938:Leukemia / Q000378:metabolism*; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000378:metabolism*; D008246:Lysophospholipids / Q000008:administration & dosage*; D037342:Pertussis Toxin / Q000494:pharmacology; D011956:Receptors, Cell Surface / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism*; D049368:Receptors, Lysophosphatidic Acid / Q000378:metabolism*
chemical_list: D008246:Lysophospholipids; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D049368:Receptors, Lysophosphatidic Acid; C025059:lysophosphatidylserine; C093426:pertussis toxin receptor; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins; D002118:Calcium