title: Cucurbitacin B inhibits STAT3 and the Raf/MEK/ERK pathway in leukemia cell line K562.
abstract: Cucurbitacin B is a natural anti-cancer compound found in Cucurbitaceae. Although the anti-cancer activity of cucurbitacin B in human leukemia cells has been reported, the underlining mechanism is still unclear. To clarify its anti-cancer activity and the mechanism of action, five different leukemia cell lines (CCRF-CEM, K562, MOLT-4, RPMI-8226 and SR) of the National Cancer Institute panel were treated with cucurbitacin B. Leukemia cell growth was inhibited by cucurbitacin B with GI(50) ranged from 15.6 nM to 35.3 nM and the growth inhibition effect was attributable to G2/M phase arrest and apoptosis. Western blotting analysis of cell signaling molecules indicated that cucurbitacin B inhibits STAT3 activation and the Raf/MEK/ERK pathway in the K562 cells.
authors.affiliation: Department of Technology and Product Development, CK Life Sciences Int'l., (Holdings) Inc., 2 Dai Fu Street, Tai Po Industrial Estate, Hong Kong SAR, China.
authors.forename: Kin Tak
authors.initials: KT
authors.lastname: Chan
authors.forename: Kwan
authors.initials: K
authors.lastname: Li
authors.forename: Shiu Lam
authors.initials: SL
authors.lastname: Liu
authors.forename: Kee Hung
authors.initials: KH
authors.lastname: Chu
authors.forename: Melvin
authors.initials: M
authors.lastname: Toh
authors.forename: Wei Dong
authors.initials: WD
authors.lastname: Xie
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D020014:K562 Cells; D020935:MAP Kinase Signaling System / Q000502:physiology*; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors*; D050796:STAT3 Transcription Factor / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects*; D014315:Triterpenes / Q000494:pharmacology*; D048490:raf Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D050796:STAT3 Transcription Factor; D014315:Triterpenes; C041246:cucurbitacin B; D048490:raf Kinases; D048049:Extracellular Signal-Regulated MAP Kinases; D020929:Mitogen-Activated Protein Kinase Kinases