title: Modulation of multidrug resistance in cancer cells by the E3 ubiquitin ligase seven-in-absentia homologue 1.
abstract: Seven-in-absentia homologue 1 (Siah1) is an E3 ubiquitin ligase that regulates the ubiquitination and proteasome-dependent degradation of a number of proteins. Here we report that Siah1 modulates multidrug resistance 1 (MDR1)/P-glycoprotein-mediated drug resistance in the cancer cell lines examined. Siah1, but not its ligase-dead mutant, down-regulates MDR1/P-glycoprotein and sensitizes the multidrug-resistant cells to chemotherapeutic agents. Mechanistically, Siah1 does not promote P-glycoprotein degradation but decreases its expression transcriptionally by promoting c-Jun transcription factor binding to the activator protein 1 (AP1) site in the MDR1 promoter. Moreover, Siah1 triggers c-Jun NH2-terminal kinase (JNK) activation, leading to enhanced phosphorylation of c-Jun, and the JNK/c-Jun signalling axis is critical for Siah1 to down-regulate MDR1/P-glycoprotein expression. These findings demonstrate a previously unidentified role for Siah1 in regulating MDR1/P-glycoprotein expression through the JNK/c-Jun pathway.
authors.affiliation: Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin 300071, People's Republic of China.
authors.forename: M
authors.initials: M
authors.lastname: Liu
authors.forename: R
authors.initials: R
authors.lastname: Aneja
authors.forename: H
authors.initials: H
authors.lastname: Wang
authors.forename: L
authors.initials: L
authors.lastname: Sun
authors.forename: X
authors.initials: X
authors.lastname: Dong
authors.forename: L
authors.initials: L
authors.lastname: Huo
authors.forename: Hc
authors.initials: H
authors.lastname: Joshi
authors.forename: J
authors.initials: J
authors.lastname: Zhou
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D015536:Down-Regulation; D018432:Drug Resistance, Multiple / Q000235:genetics; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D009363:Neoplasm Proteins / Q000502:physiology; D009369:Neoplasms / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins / Q000502:physiology*; D011401:Promoter Regions, Genetic; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D015398:Signal Transduction; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014407:Tumor Cells, Cultured; D044767:Ubiquitin-Protein Ligases / Q000502:physiology*; D000098563:Seven in Absentia Proteins
chemical_list: C513055:ABCB1 protein, human; D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D016755:Proto-Oncogene Proteins c-jun; D018808:Transcription Factor AP-1; D044767:Ubiquitin-Protein Ligases; D000098563:Seven in Absentia Proteins