title: YB-1 facilitates basal and 5-fluorouracil-inducible expression of the human major vault protein (MVP) gene.
abstract: Vaults have been suggested to play a direct role in multidrug resistance (MDR) to anticancer drugs. The human major vault protein (MVP) also known as lung resistance-related protein (LRP) represents the predominant component of vaults that may be involved in the defense against xenobiotics. Here, we demonstrate that besides MDR-related cytostatics, also the non-MDR-related drug 5-fluorouracil (5-FU) was able to induce MVP mRNA and protein expression. Treatment with 5-FU amplified the binding activity and interaction of the transcription factor Y-box binding protein-1 (YB-1) with the Y-box of the human MVP gene promoter in a time-dependent manner. 5-FU also induced reporter expressions driven by a panel of newly generated MVP promoter deletion mutants. Interestingly, stably YB-1 overexpressing cell clones showed enhanced binding of YB-1 to the Y-box motif, associated with enhanced basal as well as 5-FU-inducible MVP promoter-driven reporter expressions. Moreover, transduction of YB-1 cDNA led to increased expression of endogenous MVP protein. Under physiological conditions, we observed a strong coexpression of MVP and YB-1 in human colon carcinoma specimen. In summary, our data demonstrate a direct involvement of YB-1 in controlling basal and 5-FU-induced MVP promoter activity. Therefore, YB-1 is directly linked to MVP-mediated drug resistance.
authors.affiliation: Max-Delbrück-Center for Molecular Medicine, Robert-Rössle-Strasse 10, 13092 Berlin, Germany. ustein@mdc-berlin.de
authors.forename: Ulrike
authors.initials: U
authors.lastname: Stein
authors.forename: Stephan
authors.initials: S
authors.lastname: Bergmann
authors.forename: George L
authors.initials: GL
authors.lastname: Scheffer
authors.forename: Rik J
authors.initials: RJ
authors.lastname: Scheper
authors.forename: Hans-Dieter
authors.initials: HD
authors.lastname: Royer
authors.forename: Peter M
authors.initials: PM
authors.lastname: Schlag
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Walther
mesh_terms: D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology*; D003110:Colonic Neoplasms / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000187:drug effects / Q000378:metabolism*; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm / Q000502:physiology*; D024202:Electrophoretic Mobility Shift Assay; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D005472:Fluorouracil / Q000494:pharmacology*; D006801:Humans; D007150:Immunohistochemistry; D009687:Nuclear Proteins; D011401:Promoter Regions, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020394:Vault Ribonucleoprotein Particles / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D051840:Y-Box-Binding Protein 1; D000099187:Major Vault Protein
chemical_list: D000964:Antimetabolites, Antineoplastic; D004268:DNA-Binding Proteins; D005472:Fluorouracil; D009687:Nuclear Proteins; D020394:Vault Ribonucleoprotein Particles; D051840:Y-Box-Binding Protein 1; D000099187:Major Vault Protein; C070856:YBX1 protein, human