Breast cancer metastasis suppressor 1 inhibits gene expression by targeting nuclear factor-κB activity

Academic Article

Abstract

  • Breast cancer metastasis suppressor 1 (BRMS1) functions as a metastasis suppressor gene in breast cancer and melanoma cell lines, but the mechanism of BRMS1 suppression remains unclear. We determined that BRMS1 expression was inversely correlated wills that of urokinase-type plasminogen activator (uPA), a prometastatic gene that is regulated at least in part by nuclear factor-κB (NF-κB). To further investigate the role of NF-κB in BRMS1-regulated gene expression, we examined NF-κB binding activity and found an inverse correlation between BRMS1 expression and NF-κB binding activity in MDA-MB-231 breast cancer and C8161.9 melanoma cells stably expressing BRMS1. In contrast, BRMS1 expression had no effect on activation of the activator protein-1 transcription factor. Further, we showed that suppression of both constitutive and tumor necrosis factor-α-induced NF-κB activation by BRMS1 may be due to inhibition of IκBα phosphorylation and degradation. To examine the relationship between BRMS1 and uPA expression in primary breast tumors, we screened a breast cancer dot blot array of normalized cDNA from 50 breast tumors and corresponding normal breast tissues. There was a significant reduction in BRMS1 mRNA expression in breast tumors compared with matched normal breast tissues (paired t test, P < 0.0091) and a general inverse correlation with uPA gene expression (P < 0.01). These results suggest that at least one of the underlying mechanisms of BRMS1-dependent suppression of tumor metastasis includes inhibition of NF-κB activity and subsequent suppression of uPA expression in breast cancer and melanoma cells. ©2005 American Association for Cancer Research.
  • Published In

  • Cancer Research  Journal
  • Digital Object Identifier (doi)

    Author List

  • Cicek M; Fukuyama R; Welch DR; Sizemore N; Casey G
  • Start Page

  • 3586
  • End Page

  • 3595
  • Volume

  • 65
  • Issue

  • 9