IKK assay
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To determine the effect of CDDO-Me on TNF-induced IKK activation, IKK was analyzed. Briefly, the IKK complex from whole-cell extracts was precipitated with antibody against IKKα and IKKβ and then treated with protein A/G-Sepharose beads. After 2 hrs, the beads were washed with lysis buffer and then resuspended in a kinase assay mixture containing 50 mmol/L HEPES (pH 7.4), 20 mmol/L MgCl2, 2 mmol/L DTT, 20 μCi [γ-32P]ATP, 10 μmol/L unlabeled ATP, and 2 μg of substrate glutathione S-transferase-IκBα (amino acids 1 ~ 54). After incubation at 30°C for 30 mins, the reaction was terminated by boiling with SDS sample buffer for 5 mins. Finally, the protein was resolved on 10% SDS-PAGE, the gel was dried, and the radioactive bands were visualized with a Storm820. To determine the total amounts of IKK-α and IKK-β in each sample, 50 μg of whole-cell proteins were resolved on 7.5% SDS-PAGE, electrotransferred to a nitrocellulose membrane, and then blotted with either anti-IKK-α or anti-IKK-β antibody.
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Applications
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In leukemia cells, such as HL-60, KG-1, and NB4 cells, Bardoxolone Methyl decreased cell viability with the IC50 values of 0.4, 0.4 and 0.27 μM, respectively.
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References:
[1]. Shishodia S, Sethi G, Konopleva M, Andreeff M, Aggarwal BB. A synthetic triterpenoid, CDDO-Me, inhibits IkappaBalpha kinase and enhances apoptosis induced by TNF and chemotherapeutic agents through down-regulation of expression of nuclear factor kappaB-regulated gene products in human leukemic cells. Clin Cancer Res. 2006 Mar 15;12(6):1828-38.
[2]. Konopleva M, Tsao T, Ruvolo P, Stiouf I, Estrov Z, Leysath CE, Zhao S, Harris D, Chang S, Jackson CE, Munsell M, Suh N, Gribble G, Honda T, May WS, Sporn MB, Andreeff M. Novel triterpenoid CDDO-Me is a potent inducer of apoptosis and differentiation in acute myelogenous leukemia. Blood. 2002 Jan 1;99(1):326-35.
[3]. Liby K, Royce DB, Williams CR, Risingsong R, Yore MM, Honda T, Gribble GW, Dmitrovsky E, Sporn TA, Sporn MB. The synthetic triterpenoids CDDO-methyl ester and CDDO-ethyl amide prevent lung cancer induced by vinyl carbamate in A/J mice. Cancer Res. 2007 Mar 15;67(6):2414-9.
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