Benzoxathiole derivative blocks lipopolysaccharide-induced nuclear factor-kappaB activation and nuclear factor-kappaB-regulated gene transcription through inactivating inhibitory kappaB kinase beta.
Benzoxathiole derivatives have been used in the treatment of acne and have shown cytostatic, antipsoriatic, and antibacterial properties. However, little is known about the molecular basis for these pharmacological properties, although nuclear factor (NF)-kappaB activation is closely linked to inflammation and cell proliferation. Here, we demonstrate that the novel small-molecule benzoxathiole 6,6-dimethyl-2-(phenylimino)-6,7-dihydro-5H-benzo-[1,3]oxathiol-4-one (BOT-64) inhibits NF-kappaB activation with an IC(50) value of 1 muM by blocking inhibitory kappaB(IkappaB) kinase beta (IKKbeta), and suppresses NF-kappaB-regulated expression of inflammatory genes in lipopolysaccharide (LPS)-activated RAW 264.7 macrophages. BOT-64 inhibits IKKbeta-mediated IkappaBalpha phosphorylation in LPS-activated macrophages, resulting in sequential prevention of downstream events, including proteolytic degradation of IkappaBalpha, DNA binding ability, and transcriptional activity of NF-kappaB. BOT-64 inhibits LPS-inducible IKKbeta activity in the cells and catalytic activity of highly purified IKKbeta. Moreover, the effect of BOT-64 on cell-free IKKbeta was abolished by substitution of Ser-177 and Ser-181 residues in the activation loop of IKKbeta to glutamic acid residues, indicating a direct interaction site of benzoxathiole. BOT-64 attenuates NF-kappaB-regulated expression of inflammatory genes such as inducible nitric-oxide synthase, cyclooxygenase-2, tumor necrosis factor-alpha, interleukin (IL)-1beta, and IL-6 in LPS-activated or expression vector IKKbeta-transfected macrophages. Furthermore, BOT-64 dose-dependently increases the survival rates of endotoxin LPS-shocked mice.
Kim
Byung Hak
BH
College of Pharmacy, Chungbuk National University, Cheongju 361-763, Korea.
Roh
Eunmiri
E
Lee
Hwa Young
HY
Lee
In-Jeong
IJ
Ahn
Byeongwoo
B
Jung
Sang-Hun
SH
Lee
Heesoon
H
Han
Sang-Bae
SB
Kim
Youngsoo
Y
D000818:Animals; D002384:Catalysis / Q000187:drug effects; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D051550:I-kappa B Kinase / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D020672:I-kappa B Proteins / Q000378:metabolism; D007249:Inflammation / Q000235:genetics; D018836:Inflammation Mediators / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008262:Macrophage Activation / Q000187:drug effects; D008264:Macrophages / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D051379:Mice; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D012772:Shock, Septic / Q000139:chemically induced / Q000517:prevention & control; D015398:Signal Transduction / Q000187:drug effects; D013438:Sulfhydryl Compounds / Q000494:pharmacology*; D014158:Transcription, Genetic / Q000187:drug effects*
C527695:6,6-dimethyl-2-(phenylimino)-6,7-dihydro-5H-benzo-(1,3)oxathiol-4-one; D020672:I-kappa B Proteins; D018836:Inflammation Mediators; D008070:Lipopolysaccharides; D016328:NF-kappa B; C000606204:NFKBIA protein, human; C000606205:Nfkbia protein, mouse; D013438:Sulfhydryl Compounds; D000072000:NF-KappaB Inhibitor alpha; D051550:I-kappa B Kinase