title: Brusatol-induced HL-60 cell differentiation involves NF-kappaB activation.
abstract: Brusatol, a quassinoid isolated from the fruit of Brucea javanica, induces cell differentiation with various leukemic cell lines in the concentration range of 5-25 ng/ml. To investigate its mechanism of action, cultured HL-60 cells were treated with brusatol (25 ng/ml) for various periods of time and qualitatively analyzed for differential gene expression using a cDNA macroarray. As suggested by these preliminary data, we investigated the effect of brusatol on the Rel/nuclear factor-kappa B (NF-kappaB) family members and their role in HL-60 cell differentiation. When cells were treated with brusatol (25 ng/ml), p100/p52, p105/p50 and p65 mRNA were found to be up-regulated with a maximum after 8 h. As determined by electrophoretic mobility shift assays (EMSA), NF-kappaB was activated, involving p50 and p65. Moreover, immunoblots showed a decrease of IkappaBalpha and generation of the phosphorylated form of IkappaBalpha in whole cell lysates. Cell differentiation induced by brusatol was inhibited by SN50, a NF-kappaB translocation inhibitor. These results strongly suggest that brusatol induces activation of NF-kappaB and the activation and translocation of NF-kappaB into the nucleus is responsible for promoting HL-60 cell differentiation.
authors.affiliation: Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, Chicago, IL, USA.
authors.forename: Muriel
authors.initials: M
authors.lastname: Cuendet
authors.forename: Joell J
authors.initials: JJ
authors.lastname: Gills
authors.forename: John M
authors.initials: JM
authors.lastname: Pezzuto
mesh_terms: D002454:Cell Differentiation / Q000187:drug effects*; D002467:Cell Nucleus; D024202:Electrophoretic Mobility Shift Assay; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D018922:HL-60 Cells; D006801:Humans; D020672:I-kappa B Proteins / Q000378:metabolism*; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D010455:Peptides / Q000494:pharmacology; D021381:Protein Transport / Q000187:drug effects; D036702:Quassins / Q000494:pharmacology*
chemical_list: D020672:I-kappa B Proteins; D016328:NF-kappa B; C000606204:NFKBIA protein, human; D010455:Peptides; D036702:Quassins; C118258:SN50 peptide; D000072000:NF-KappaB Inhibitor alpha; C020237:brusatol