BRMS1 contributes to the negative regulation of uPA gene expression through recruitment of HDAC1 to the NF-kappaB binding site of the uPA promoter.
The BRMS1 metastasis suppressor was recently shown to negatively regulate NF-kappaB signaling and down regulate NF-kappaB-dependent uPA expression. Here we confirm that BRMS1 expression correlates with reduced NF-kappaB DNA binding activity in independently derived human melanoma C8161.9 cells stably expressing BRMS1. We show that knockdown of BRMS1 expression in these cells using small interfering RNA (siRNA) leads to the reactivation of NF-kappaB DNA binding activity and re-expression of uPA. Further, we confirm that BRMS1 expression does not alter IKKbeta kinase activity suggesting that BRMS1-dependent uPA regulation does not occur through inhibition of the classical upstream activators of NF-kappaB. BRMS1 has been implicated as a corepressor of HDAC1 and consistent with this, we show that BRMS1 promotes HDAC1 recruitment to the NF-kappaB binding site of the uPA promoter and is associated with reduced H3 acetylation. We also confirm that BRMS1 expression stimulates disassociation of p65 from the NF-kappaB binding site of the uPA promoter consistent with its reduced DNA binding activity. These data suggest that BRMS1 recruits HDAC1 to the NF-kappaB binding site of the uPA promoter, modulates histone acetylation of p65 on the uPA promoter, leading to reduced NF-kappaB binding activity on its consensus sequence, and reduced transactivation of uPA expression.
Cicek
Muzaffer
M
Endocrine Research Unit, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA.
Fukuyama
Ryuichi
R
Cicek
Mine S
MS
Sizemore
Steven
S
Welch
Danny R
DR
Sizemore
Nywana
N
Casey
Graham
G
D000107:Acetylation; D001665:Binding Sites; D045744:Cell Line, Tumor; D015972:Gene Expression Regulation, Neoplastic; D056284:Histone Deacetylase 1; D006655:Histone Deacetylases / Q000378:metabolism*; D006801:Humans; D016328:NF-kappa B / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000502:physiology*; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012097:Repressor Proteins; D015398:Signal Transduction / Q000502:physiology; D051996:Transcription Factor RelA / Q000378:metabolism; D015533:Transcriptional Activation; D014568:Urokinase-Type Plasminogen Activator / Q000096:biosynthesis* / Q000235:genetics
C410024:BRMS1 protein, human; D016328:NF-kappa B; D009363:Neoplasm Proteins; D012097:Repressor Proteins; D051996:Transcription Factor RelA; D014568:Urokinase-Type Plasminogen Activator; C110550:HDAC1 protein, human; D056284:Histone Deacetylase 1; D006655:Histone Deacetylases