title: PU-H71 effectively induces degradation of IκB kinase β in the presence of TNF-α.
abstract: This study is to determine if PU-H71, a heat shock protein inhibitor, induces killing of malignant breast cells together with treatment of tumor necrosis factor-α (TNF-α). The related molecular mechanisms were also studied. A primary mammary epithelial cell line HMEC2595 cells and the highly metastatic breast cell line MDA-MB-231, the HER2-positive BT-474 cells, and the ER-positive MCF7 cells were treated with PU-H71 in the presence or absence of TNF-α. The effects of PU-H71 and TNF-α treatments on cells viabilities and on intracellular signaling pathway proteins were determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, apoptosis assays, immunoblot assays, and luciferase assays. It was found that TNF-α enhances the toxic effects of PU-H71 on tumor cells but not normal cells. PU-H71 treatments lead to degradation of IKKβ. Moreover, PU-H71 down-regulates the NF-κB transcriptional activity induced by TNF-α treatment. The experimental results indicated PU-H71 effectively induces cell killing of malignant breast cells in the presence of TNF-α, possibly through a mechanism related to degradation of IKKβ. It is suggested that combination of PU-H71 and TNF-α treatments might be an effective therapeutic strategy of breast malignancies.
authors.affiliation: The Affiliated Hospital of Medical College, Qingdao University, Qingdao, 266021, Shandong Province, China, quzhuling@126.com.
authors.forename: Zhuling
authors.initials: Z
authors.lastname: Qu
authors.forename: Shiduan
authors.initials: S
authors.lastname: Wang
authors.forename: Ruyang
authors.initials: R
authors.lastname: Teng
authors.forename: Xuanlong
authors.initials: X
authors.lastname: Yi
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D001483:Base Sequence; D052117:Benzodioxoles / Q000494:pharmacology*; D002460:Cell Line; D045744:Cell Line, Tumor; D017931:DNA Primers; D015536:Down-Regulation; D006801:Humans; D051550:I-kappa B Kinase / Q000378:metabolism*; D059748:Proteolysis; D011687:Purines / Q000494:pharmacology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
chemical_list: D052117:Benzodioxoles; D017931:DNA Primers; D011687:Purines; D014409:Tumor Necrosis Factor-alpha; C526550:9H-purine-9-propanamine, 6-amino-8-((6-iodo-1,3-benzodioxol-5-yl)thio)-N-(1-methylethyl)-; D051550:I-kappa B Kinase