title: Expression of Ca(2+)-independent and Ca(2+)-dependent phospholipases A(2) and cyclooxygenases in human melanocytes and malignant melanoma cell lines.
abstract: We provide novel evidence that human melanoma cell lines (M10, M14, SK-MEL28, SK-MEL93, 243MEL, 1074MEL, OCM-1, and COLO38) expressed, at mRNA and protein levels, either Ca(2+)-independent phospholipase A(2) (iPLA(2)) or cytosolic phospholipase A(2) (cPLA(2)) and its phosphorylated form. Normal human melanocytes contained the lowest levels of both PLA(2)s. Cyclooxygenase-1 and -2 (COX-1 and COX-2) were also expressed in cultured tumor cells as measured by Western blots. The most pronounced overexpression of iPLA(2) and COX-1 was found in two melanoma-derived cells, M14 and COLO38. Normal human melanocytes and the M10 melanoma cell line displayed no COX-2 expression. Using subcellular fractionation, Western blot and confocal microcopy analyses, in paradigmatic SK-MEL28 and SK-MEL93 cells we showed that iPLA(2), COX-1 and even cPLA(2) were equally located in the cytosol, membrane structures and perinuclear region while COX-2 was preferentially associated with the cytosol. Specific inhibitors of these three enzymes significantly reduced the basal proliferation rate either in melanocytes or in melanoma cell lines. These results, coupled with the inhibition of the cell proliferation by electroporation of melanoma cells with cPLA(2) or COX-2 antibodies, demonstrate that a possible correlation between PLA(2)-COX expression and tumor cell proliferation in the melanocytic system does exist. In addition, the high expression level of both PLA(2)s and COXs suggests that eicosanoids modulate cell proliferation and tumor invasiveness.
authors: Department of Experimental and Clinical Pharmacology, University of Catania, viale Andrea Doria 6, 95125 Catania, Italy.
authors: Mariagrazia Rita
authors: MR
authors: Scuderi
authors: Carmelina Daniela
authors: CD
authors: Anfuso
authors: Gabriella
authors: G
authors: Lupo
authors: Carla
authors: C
authors: Motta
authors: Loriana
authors: L
authors: Romeo
authors: Liliana
authors: L
authors: Guerra
authors: Alessandro
authors: A
authors: Cappellani
authors: Nicola
authors: N
authors: Ragusa
authors: Giuseppina
authors: G
authors: Cantarella
authors: Mario
authors: M
authors: Alberghina
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology / Q000494:pharmacology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D051545:Cyclooxygenase 1 / Q000235:genetics / Q000378:metabolism; D051546:Cyclooxygenase 2 / Q000276:immunology / Q000378:metabolism; D052246:Cyclooxygenase 2 Inhibitors / Q000494:pharmacology; D003600:Cytosol / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D054501:Group II Phospholipases A2 / Q000235:genetics / Q000378:metabolism; D006801:Humans; D048369:MAP Kinase Kinase 1 / Q000037:antagonists & inhibitors; D008544:Melanocytes / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D008545:Melanoma / Q000201:enzymology / Q000235:genetics / Q000473:pathology; D015388:Organelles / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D064801:Phospholipase A2 Inhibitors; D054467:Phospholipases A2 / Q000235:genetics / Q000378:metabolism*; D054512:Phospholipases A2, Calcium-Independent / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology
chemical_list: D000911:Antibodies, Monoclonal; D052246:Cyclooxygenase 2 Inhibitors; D004791:Enzyme Inhibitors; D000081082:Phosphoinositide-3 Kinase Inhibitors; D064801:Phospholipase A2 Inhibitors; D047428:Protein Kinase Inhibitors; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; C496511:PTGS1 protein, human; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D048369:MAP Kinase Kinase 1; C482125:MAP2K1 protein, human; D054501:Group II Phospholipases A2; D054467:Phospholipases A2; D054512:Phospholipases A2, Calcium-Independent