Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10817121 | Cellular Signalling | 2005 | 12 Pages |
Abstract
In this study, we investigated the signaling pathway involved in cyclooxygenase-2 (COX-2) expression and prostaglandin E2 (PGE2) release by phorbol 12-myristate 13-acetate (PMA), a protein kinase C (PKC) activator, in human pulmonary epithelial cells (A549). PMA-induced COX-2 expression was attenuated by PKC inhibitors (Go 6976 and Ro 31-8220), a Ras inhibitor (manumycin A), a Raf-1 inhibitor (GW 5074), a MEK inhibitor (PD 098059), and an NF-κB inhibitor (PDTC), but not by a tyrosine kinase inhibitor (genistein) or a p38 MAPK inhibitor (SB 203580). PMA also caused the activation of Ras, Raf-1, and ERK1/2. PMA-induced activation of Ras and Raf-1 was inhibited by Ro 31-8220 and manumycin A. PMA-mediated activation of ERK1/2 was inhibited by Ro 31-8220, manumycin A, GW 5074, and PD 098059. Stimulation of cells with PMA caused IκBα phosphorylation, IκBα degradation, and the formation of a NF-κB-specific DNA-protein complex. The PMA-mediated increase in κB-luciferase activity was inhibited by Ro 31-8220, manumycin A, GW5074, PD 098059, and PDTC. Taken together, these results indicate that PMA might activate PKC to elicit activation of the Ras/Raf-1/ERK1/2 pathway, which in turn initiates NF-κB activation, and finally induces COX-2 expression and PGE2 release in A549 cells.
Keywords
ECLEMSAMLBPDTCPhorbol-12-myristate-13-acetateRAF-1IKKPKCFCSNF-κBPGE2RASCOX-2PBSLPSERKERK1/2IκB kinasePMAMAPKMAPK/ERK kinaseElectrophoretic mobility shift assaysodium dodecyl sulfate-polyacrylamide gel electrophoresisSDS-PAGEenhanced chemiluminescencetumor necrosis factor-αpyrrolidine dithiocarbamatefetal calf serumA549 cellsCyclooxygenase-2TNF-αnuclear factor-κBlipopolysaccharideMEKPhosphate-buffered salineProtein kinase Cmitogen-activated protein kinaseProstaglandin E2extracellular signal-regulated kinase
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Authors
Ming-Shyan Chang, Bing-Chang Chen, Ming-Tze Yu, Joen-Rong Sheu, Tseng-Fu Chen, Chien-Huang Lin,