ucn-1028-c and Esophageal-Neoplasms

Mucin alterations are a common feature of esophageal neoplasia, and alterations in MUC2 mucin have been associated with tumor progression in the esophagus. Bile acids have been linked to esophageal adenocarcinoma and mucin secretion, but their effects on mucin gene expression in human esophageal adenocarcinoma cells is unknown.. Human esophageal adenocarcinoma cells were treated 18 hours with 50-300 muM deoxycholic acid, chenodeoxycholic acid, or taurocholic acid. MUC2 transcription was assayed using a MUC2 promoter reporter luciferase construct and MUC2 protein was assayed by Western blot analysis. Transcription Nuclear factor-kappaB activity was measured using a Nuclear factor-kappaB reporter construct and confirmed by Western blot analysis for Nuclear factor-kappaB p65.. MUC2 transcription and MUC2 protein expression were increased four to five fold by bile acids in a time and dose-dependent manner with no effect on cell viability. Nuclear factor-kappaB activity was also increased. Treatment with the putative chemopreventive agent aspirin, which decreased Nuclear factor-kappaB activity, also decreased MUC2 transcription. Nuclear factor-kappaB p65 siRNA decreased MUC2 transcription, confirming the significance of Nuclear factor-kappaB in MUC2 induction by deoxycholic acid. Calphostin C, a specific inhibitor of protein kinase C (PKC), greatly decreased bile acid induced MUC2 transcription and Nuclear factor-kappaB activity, whereas inhibitors of MAP kinase had no effect.. Deoxycholic acid induced MUC2 overexpression in human esophageal adenocarcinoma cells by activation of Nuclear factor-kappaB transcription through a process involving PKC-dependent but not PKA, independent of activation of MAP kinase.

Topics: Adenocarcinoma; Analysis of Variance; Aspirin; Cell Line, Tumor; Chenodeoxycholic Acid; Cholagogues and Choleretics; Cyclic AMP-Dependent Protein Kinases; Deoxycholic Acid; Esophageal Neoplasms; Gastrointestinal Agents; Gene Expression Regulation, Neoplastic; Humans; Mucin-2; Naphthalenes; NF-kappa B; Protein Kinase C; RNA, Small Interfering; Signal Transduction; Taurocholic Acid

Histone deacetylase inhibitors mediate a potent growth-inhibitory effect in cancer cells through induction of cell-cycle arrest and apoptosis. Moreover, these agents significantly induce transcriptional activation of nuclear factor kappaB, as well as p21 regulated by protein kinase C, and are thought to negatively influence the ability of histone deacetylase inhibitor to effectively mediate apoptosis. This study aimed to evaluate the effect of calphostin C (a protein kinase C inhibitor) on trichostatin A (a histone deacetylase inhibitor)-mediated upregulation of nuclear factor kappaB and p21 promotor transcriptional activity, as well as induction of apoptosis in lung and esophageal cancer cells.. Cultured lung and esophageal cancer cells were treated with calphostin C and trichostatin A. Nuclear factor kappaB transcriptional activity was quantitated by using the nuclear factor kappaB-luciferase assay. Transcription of p21 gene and p21 protein levels was evaluated by using the p21 promoter-luciferase assay and the p21 enzyme-linked immunoassay, respectively. Apoptosis was evaluated by using the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling-based ApoBrdU assay. Levels of expression of nuclear factor kappaB-dependent antiapoptotic and proapoptotic proteins were evaluated by means of Western blotting.. Exposure of lung or esophageal cancer cells to trichostatin A resulted in a dose- and cell-dependent 2-fold to greater than 20-fold increase of nuclear factor kappaB and p21 transcriptional activity. Treatment with trichostatin A and calphostin C led to a 50% to 90% decrease of trichostatin A- mediated upregulation of nuclear factor kappaB and p21 activation. Inhibition of nuclear factor kappaB activity resulted in significant reduction (30% to >99%) of trichostatin A- mediated activation of not only nuclear factor kappaB transcription but also p21 promotor activity. Importantly, 90% to 96% of thoracic cancer cells under-went apoptosis after exposure to the combination of trichostatin A plus calphostin C.. Inhibition of protein kinase C abrogates trichostatin A-mediated upregulation of nuclear factor kappaB transcriptional activity and p21 expression that is associated with profound induction of apoptosis in lung or esophageal cancer cells. Protein kinase C might be a novel target for enhancing the efficacy of histone deacetylase inhibitor in cancer therapy.

Topics: Apoptosis; Blotting, Western; Cell Proliferation; Cell Survival; Drug Therapy, Combination; Esophageal Neoplasms; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Lung Neoplasms; Naphthalenes; NF-kappa B; Oncogene Protein p21(ras); Probability; Protein Kinase C; Risk Factors; Sensitivity and Specificity; Tumor Cells, Cultured; Up-Regulation