trichostatin-a and Uveal-Neoplasms

Metastasis is responsible for the death of most cancer patients, yet few therapeutic agents are available which specifically target the molecular events that lead to metastasis. We recently showed that inactivating mutations in the tumor suppressor gene BAP1 are closely associated with loss of melanocytic differentiation in uveal melanoma (UM) and metastasis. The purpose of this study was to identify therapeutic agents that reverse the phenotypic effects of BAP1 loss in UM.. In silico screens were done to identify therapeutic compounds predicted to differentiate UM cells using Gene Set Enrichment Analysis and Connectivity Map databases. Valproic acid (VPA), trichostatin A, LBH-589, and suberoylanilide hydroxamic acid were evaluated for their effects on UM cells using morphologic evaluation, MTS viability assays, bromodeoxyuridine incorporation, flow cytometry, clonogenic assays, gene expression profiling, histone acetylation and ubiquitination assays, and a murine xenograft tumorigenicity model.. Histone deacetylase (HDAC) inhibitors induced morphologic differentiation, cell-cycle exit, and a shift to a differentiated, melanocytic gene expression profile in cultured UM cells. VPA inhibited the growth of UM tumors in vivo.. These findings suggest that HDAC inhibitors may have therapeutic potential for inducing differentiation and prolonged dormancy of micrometastatic disease in UM.

Topics: Animals; Antineoplastic Agents; Cell Differentiation; Cell Line, Tumor; Cell Proliferation; Chemoradiotherapy, Adjuvant; Computer Simulation; Gene Knockdown Techniques; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Indoles; Melanoma; Mice; Mice, Inbred NOD; Mice, SCID; Models, Biological; Neoplasm Micrometastasis; Panobinostat; Tumor Burden; Tumor Suppressor Proteins; Ubiquitin Thiolesterase; Uveal Neoplasms; Valproic Acid; Vorinostat; Xenograft Model Antitumor Assays

Uveal melanoma (UM) is the most common primary malignant ocular tumor in adults. No effective chemotherapy regimens are available for either intraocular or metastatic uveal melanoma. Therefore, the ability of the histone deacetylase inhibitors (HDACIs), depsipeptide, sodium butyrate (NaB) and trichostatin A (TSA), to induce apoptosis and inhibit cell growth of UM cell lines in vitro was examined.. Three primary and two metastatic UM cell lines were treated in vitro with different concentrations of histone deacetylase inhibitors (HDACIs). Cell proliferation was studied in 24-well plates. Induction of apoptosis was studied by flow cytometry. Changes in gene expression of Fas/FasL, p21(Waf/Cip1), and p27(Kip1) were studied by RT-PCR. Western blot analysis was used to study histone acetylation, Fas/FasL, p21(Waf/Cip1), p27(Kip1) and caspase-3 protein levels. Real-time PCR was used to study changes in bcl-2/bax gene expression.. A dose-dependent increase in histone acetylation was observed in all cell lines. This corresponded to significant inhibition of cell growth and induction of apoptosis in all melanoma cell lines in a concentration-dependent manner. Western blot analysis revealed dose-dependent increases in the amount of caspase-3, Fas/FasL, p21(Waf/Cip1), and p27(Kip1) proteins. However, no changes in bcl-2/bax gene expression were detected by real-time PCR.. HDACIs are potent inhibitors of primary and metastatic UM cell growth in vitro. The apoptosis is probably mediated through the Fas/FasL signaling pathway, whereas bcl-2 appears not to be involved. These data support further clinical evaluation of depsipeptide and other HDACIs in patients with primary and metastatic UM.

Topics: Antibiotics, Antineoplastic; Apoptosis; bcl-2-Associated X Protein; Blotting, Western; Butyrates; Caspase 3; Caspases; Cell Cycle Proteins; Cell Division; Cyclin-Dependent Kinase Inhibitor p21; Cyclin-Dependent Kinase Inhibitor p27; Cyclins; Depsipeptides; Dose-Response Relationship, Drug; Enzyme Inhibitors; Fas Ligand Protein; fas Receptor; Flow Cytometry; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Melanoma; Membrane Glycoproteins; Peptides, Cyclic; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Tumor Cells, Cultured; Tumor Suppressor Proteins; Uveal Neoplasms