title: The signaling mechanisms mediating the inhibitory effect of TCH-1116 on formyl peptide-stimulated superoxide anion generation in neutrophils.
abstract: In fMLP (formyl-Met-Leu-Phe)-stimulated rat neutrophils, a mixture of regioisomers benzo[a]furo[2,3-c]phenazine-10-carboxylic acid and benzo[a]furo[2,3-c]phenazine-11-carboxylic acid (TCH-1116) inhibited O(2)(-) (superoxide anion) generation, which was not mediated by scavenging the generated O(2)(-) or by a cytotoxic effect on neutrophils. TCH-1116 had no effect on the arachidonic acid-induced NADPH oxidase activation in a cell-free system, whereas it effectively attenuated the phosphorylation of Ser residues in p47(phox) and the association between p47(phox) and p22(phox) in fMLP-stimulated neutrophils. The interaction of p47(phox) with PKC (protein kinase C) isoforms (α, βI, βII, δ and ζ) was attenuated by TCH-1116, whereas TCH-1116 did not affect the PKC isoforms membrane translocation, phosphorylation (Ser660) and kinase activity. TCH-1116 effectively attenuated the association between PKB/Akt (protein kinase B) and p47(phox), Akt phosphorylation (Thr308/Ser473) and kinase activities of Akt and human recombinant PDK (3-phosphoinositide-dependent kinase) 1, whereas it had no effect on recruitment of Akt, phospho-PDK1 (Ser241) and p110γ to membrane. Moreover, the interaction of p21-activated kinase (PAK) 1 with p47(phox) and the phosphorylation of PAK1 (Thr423 but not Ser144) were inhibited by TCH-1116, but without affecting the membrane recruitment of PAK1. The cellular cyclic AMP level was not changed by TCH-1116. Taken together, these results suggest that TCH-1116 inhibits fMLP-stimulated O(2)(-) generation in rat neutrophils through the blockade of PKC, Akt and PAK signaling pathways.
authors.affiliation: Graduate Institute of Pharmaceutical Chemistry, China Medical University, Taichung 404, Taiwan, ROC.
authors.forename: Ya-Ru
authors.initials: YR
authors.lastname: Tsai
authors.forename: Li-Jiau
authors.initials: LJ
authors.lastname: Huang
authors.forename: Miau-Rong
authors.initials: MR
authors.lastname: Lee
authors.forename: Yeh-Long
authors.initials: YL
authors.lastname: Chen
authors.forename: Sheng-Chu
authors.initials: SC
authors.lastname: Kuo
authors.forename: Cherng-Chyi
authors.initials: CC
authors.lastname: Tzeng
authors.forename: Mei-Feng
authors.initials: MF
authors.lastname: Hsu
authors.forename: Jih-Pyang
authors.initials: JP
authors.lastname: Wang
mesh_terms: D000818:Animals; D001572:Benzofurans / Q000494:pharmacology*; D002264:Carboxylic Acids / Q000494:pharmacology*; D002474:Cell-Free System; D000242:Cyclic AMP / Q000096:biosynthesis; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology*; D019255:NADPH Oxidases / Q000378:metabolism; D009504:Neutrophils / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D010619:Phenazines / Q000494:pharmacology*; D011493:Protein Kinase C / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects*; D013481:Superoxides / Q000378:metabolism*; D054462:p21-Activated Kinases / Q000378:metabolism
chemical_list: D001572:Benzofurans; D002264:Carboxylic Acids; D010619:Phenazines; D013481:Superoxides; D009240:N-Formylmethionine Leucyl-Phenylalanine; D000242:Cyclic AMP; D019255:NADPH Oxidases; C060505:neutrophil cytosolic factor 1; D051057:Proto-Oncogene Proteins c-akt; D054462:p21-Activated Kinases; D011493:Protein Kinase C