Histone deacetylase inhibitor-induced cellular apoptosis involves stanniocalcin-1 activation

Our previous studies have demonstrated the involvement of HIF-1 and p53 in the regulation of stanniocalcin-1 (STC1) gene transcription in human cancer cells. In this study, we reported that the treatment of human colon adenoma HT29 cells with a histone deacetylase (HDAC) inhibitor (i.e. trichostatin A, TSA) induced both cellular apoptosis and STC1 expression. The activation of STC1 expression was also observed in other TSA-treated human cancer cells (i.e. SKOV3, CaCo-2, Jurkat and CNE-2 cells). STC1 mRNA was rapidly induced within 4 h in TSA-treated HT29 cells, and was found to be transcriptionally regulated and was independent of new protein synthesis as revealed by ActD and CHX treatment respectively. The induction was correlated with increased cellular levels of acetyl histone H3 and H4 and acetyl NF kappa B. Chromatin immunoprecipitation (ChIP) assay showed the increased binding of acetyl histone H3 and H4 to STC1 promoter in the TSA-treated cells. A cotreatment of HT29 cells with a NF kappa B inhibitor (parthenolide) significantly inhibited the TSA-induced cellular levels of acetyl NF kappa B p65 and abolished the stimulation of STC1 gene expression. ChIP assay also demonstrated that TSA treatment increased while TSA/parthenolide cotreatment decreased NF kappa B p65 binding to STC1 gene promoter. In the STC1-luciferase promoter construct (1 kb) study, the data implied that the promoter can be activated by TSA treatment. Interestingly, the promoter region contains 2 Putative NF kappa B binding sites. Consistent with the STC1 mRNA expression data, TSA/parthenolide cotreatment also significantly inhibited the TSA-induced STC1 promoter-driven luciferase activity. Importantly, TSA-incluced apoptotic process was found to be significantly reduced by the silencing of STC1 expression. This is the first study to show that histone hyper-acetylation and the recruitment of activated NF kappa B stimulated STC1 gene expression. In addition, our results support the notion that STC1 is a pro-apoptotic factor. (C) 2008 Elsevier Inc. All rights reserved.