PMID- 10501211 OWN - NLM STAT- MEDLINE DCOM- 19991014 LR - 20190630 IS - 0022-3042 (Print) IS - 0022-3042 (Linking) VI - 73 IP - 4 DP - 1999 Oct TI - Signaling mechanisms involved in the activation of arachidonic acid metabolism in human astrocytoma cells by tumor necrosis factor-alpha: phosphorylation of cytosolic phospholipase A2 and transactivation of cyclooxygenase-2. PG - 1641-9 AB - Tumor necrosis factor-alpha (TNF-alpha) is a cytokine that elicits cell responses by activating the mitogen-activated protein kinase (MAP kinase) cascade and transcription factors such as nuclear factor-kappaB (NF-kappaB). As these elements play a central role in the mechanisms of signaling involved in the activation of cytosolic phospholipase A2 (cPLA2) and cyclooxygenase-2 (COX-2), the effect of TNF-alpha on arachidonate (AA) metabolism in 1321N1 astrocytoma cells was assayed. TNF-alpha produced a phosphorylation of cPLA2, which was preceded by an activation of both c-Jun N-terminal kinase (JNK) and p38-MAP kinase, and this was associated with the release of [3H]AA. In contrast, TNF-alpha did not activate the extracellular signal-regulated kinase (MAP kinase) p42, nor did it elicit a mitogenic response. Analysis of [3H]AA metabolites by reverse-phase HPLC showed that all of the [3H]AA released during the first hour after TNF-alpha addition eluted as authentic AA, whereas in samples obtained at 24 h after addition of TNF-alpha, 25% of the [3H]AA had been converted into COX products as compared with only 9% in control cells. In keeping with these findings, TNF-alpha produced an increase of COX-2 expression, as judged from both RT-PCR studies and immunoblot of COX-2 protein, and a long-lasting activation of NF-kappaB. These data show that TNF-alpha produces in astrocytoma cells an early activation of both p38-MAP kinase and JNK, which is followed by the phosphorylation of cPLA2 and the release of AA. On the other hand, the activation of NF-kappaB may explain the induction of the expression of COX-2 and the delayed generation of prostanoids. FAU - Hernandez, M AU - Hernandez M AD - Instituto de Biologia y Genetica Molecular, Consejo Superior de Investigaciones Cientificas, Facultad de Medicina, Valladolid, Spain. FAU - Bayon, Y AU - Bayon Y FAU - Sanchez Crespo, M AU - Sanchez Crespo M FAU - Nieto, M L AU - Nieto ML LA - eng PT - Journal Article PT - Research Support, Non-U.S. Gov't PL - England TA - J Neurochem JT - Journal of neurochemistry JID - 2985190R RN - 0 (Isoenzymes) RN - 0 (Membrane Proteins) RN - 0 (NF-kappa B) RN - 0 (Recombinant Proteins) RN - 0 (Tumor Necrosis Factor-alpha) RN - 27YG812J1I (Arachidonic Acid) RN - EC 1.14.99.1 (Cyclooxygenase 2) RN - EC 1.14.99.1 (PTGS2 protein, human) RN - EC 1.14.99.1 (Prostaglandin-Endoperoxide Synthases) RN - EC 3.1.1.32 (Phospholipases A) RN - EC 3.1.1.4 (Phospholipases A2) SB - IM MH - Arachidonic Acid/*metabolism MH - Astrocytoma MH - Brain Neoplasms MH - Cyclooxygenase 2 MH - Cytosol/enzymology MH - Gene Expression Regulation, Enzymologic/drug effects MH - Gene Expression Regulation, Neoplastic/drug effects MH - Humans MH - Isoenzymes/*genetics MH - Kinetics MH - Membrane Proteins MH - NF-kappa B/metabolism MH - Phospholipases A/*metabolism MH - Phospholipases A2 MH - Phosphorylation MH - Prostaglandin-Endoperoxide Synthases/*genetics MH - Recombinant Proteins/pharmacology MH - Reverse Transcriptase Polymerase Chain Reaction MH - Signal Transduction/*physiology MH - Transcriptional Activation MH - Tumor Cells, Cultured MH - Tumor Necrosis Factor-alpha/*pharmacology EDAT- 1999/09/29 00:00 MHDA- 1999/09/29 00:01 CRDT- 1999/09/29 00:00 PHST- 1999/09/29 00:00 [pubmed] PHST- 1999/09/29 00:01 [medline] PHST- 1999/09/29 00:00 [entrez] AID - 10.1046/j.1471-4159.1999.0731641.x [doi] PST - ppublish SO - J Neurochem. 1999 Oct;73(4):1641-9. doi: 10.1046/j.1471-4159.1999.0731641.x.