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Phosphoinositide 3-kinase activity leads to silica-induced NF-kappaB activation through interacting with tyrosine-phosphorylated IkappaB-alpha and contributing to tyrosine phosphorylation of p65 NF-kappaB.

Authors
Kang-JL; Lee-HS; Pack-IS; Hur-KC; Castranova-V
Source
Mol Cell Biochem 2003 Jun; 248(1-2):17-24
NIOSHTIC No.
20032611
Abstract
The role of the subunits of phosphoinositide (PI) 3-kinase in NF-kappaB activation in silica-stimulated RAW 264.7 cells was investigated. Results indicate that PI3-kinase activity was increased in response to silica. The p85alpha subunit of PI3-kinase interacted with tyrosine-phosphorylated IkappaB-alpha in silica-stimulated cells. PI3-kinase specific inhibitors, such as wortmannin and LY294003, substantially blocked both silica-induced PI3-kinase and NF-kappaB activation. The inhibition of NF-kappaB activation by PI3-kinase inhibitors was also observed in pervanadate-stimulated but not in LPS-stimulated cells. Furthermore, tyrosine phosphorylation of NF-kappaB p65 was enhanced in cells stimulated with silica, pervanadate or LPS, and wortmannin substantially inhibited the phosphorylation event induced by the first two stimulants, but not LPS. Antioxidants, such as superoxide dismutase (SOD), N-acetylcysteine (NAC) and pyrrolidine dithiocarbamate (PDTC), blocked silica-induced PI3-kinase activation, suggesting that reactive oxygen species may be important regulatory molecules in NF-kappaB activation by mediating PI3-kinase activation. Our data suggest that p85 and p110 subunits of PI3-kinase play a role in NF-kappaB activation through interaction with tyrosine-phosphorylated kappaIB-alpha and contributing to tyrosine phosphorylation of p65 NF-kappaB.
Keywords
Silica-dusts; Silicates; Antioxidants; Cell-function; Cellular-reactions; Bioassays; Cell-biology; Oxidative-phosphorylation; Growth-factors; Genes; Molecular-biology; Nucleic-acids; Nucleotides
Contact
Jihee Lee Kang, Department of Physiology, College of Medicine, Ewha Womans University, 911-1 Mok-6-dong, Yangcheon-ku, Seoul 158-056, Korea
CODEN
MCBIB8
CAS No.
7631-86-9; 14808-60-7
Publication Date
20030601
Document Type
Journal Article
Email Address
jihee@mm.ewha.ac.kr
Fiscal Year
2003
NTIS Accession No.
NTIS Price
Issue of Publication
1-2
ISSN
0300-8177
NIOSH Division
HELD
Source Name
Molecular and Cellular Biochemistry
State
WV
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