Geldanamycin inhibits NF-κB activation and interleukin-8 gene expression in cultured human respiratory epithelium

Academic Article

Abstract

  • Geldanamycin is a benzoquinone ansamycin with multiple pharmacologic properties. Recent data demonstrated that geldanamycin conferred protection in an animal model of inflammation-associated acute lung iniury. In the current study, we investigated the effects of geldanamycin on interleukin (IL)-8 gene expression and nuclear factor (NF)-κB activation. Geldanamycin inhibited tumor necrosis factor (TNF)-α-mediated IL-8 gene expression in A549 human respiratory epithelial cells as measured by enzyme-linked immunosorbent assay and Northern blot analyses. In cells transiently transfected with an IL-8 promoter-luciferase reporter plasmid, geldanamycin inhibited TNF-α-mediated luciferase activity. Geldanamycin inhibited TNF-α-mediated NF-κB activation as measured by electromobility shift assays and transient transfections with a NF-κB-dependent luciferase reporter plasmid. In contrast, geldanamycin did not affect TNF-α-mediated degradation of the NF-κB inhibitory protein IκBα and did not block nuclear translocation of the NF-κB p65 subunit as measured by Western blot analyses. Geldanamycin added directly to nuclear extracts of TNF-α-treated cells reduced the formation of the NF-κB/DNA complex. These results demonstrate that geldanamycin inhibits TNF-α-mediated IL-8 gene expression in A549 cells by inhibiting activation of the IL-8 promoter. The mechanism of inhibition involves inhibition of NF-κB activation, which is independent of IκBα degradation or p65 nuclear translocation. Geldanamycin appears to directly inhibit the ability of NF-κB to bind DNA. The observed in vitro effects could account, in part, for the anti-inflammatory properties of geldanamycin observed in vivo.
  • Digital Object Identifier (doi)

    Author List

  • Malhotra V; Shanley TP; Pittet JF; Welch WJ; Wong HR
  • Start Page

  • 92
  • End Page

  • 97
  • Volume

  • 25
  • Issue

  • 1