Lysophosphatidylserine stimulates leukemic cells but not normal leukocytes.
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.
Park
Kyoung Sun
KS
Medical Research Center for Cancer Molecular Therapy, College of Medicine, Dong-A University, Busan 602-714, Republic of Korea.
Lee
Ha Young
HY
Kim
Mi-Kyoung
MK
Shin
Eun Ha
EH
Bae
Yoe-Sik
YS
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*
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