Depsipeptide (DP), Histone Deacetylase Inhibitor (HDACI), Inhibits Migration of Primary and Metastatic Uveal Melanoma (UM) Cells by Down-regulation of Matrix Metalloproteinase (MMP) 2 and 9 Gene Expression

Abstract

Abstract: : Purpose: UM is a malignant primary intraocular tumor in adults that has a high mortality rate due to hematogenous dissemination preferentially to the liver. The migration of UM cells through the basement membrane requires the presence of proteolytic enzymes such as MMPs. The expression of MMP-2 and MMP-9 in UM cells is a known risk factor for metastatic disease. We tested the ability of DP to inhibit UM cell migration in vitro and to down-regulate gene expression for MMP-2 and MMP-9. Methods: 3 primary and 2 metastatic (liver metastasis) UM cell lines were treated with DP (0,1,5 and 10 nM) for 24 hours. Migration of UM cells was studied in modified Boyden migration chambers for 24 hours (Hendrix et al. 1998) and only viable cells on both sides of the membrane were counted. Changes in MMP-2 and MMP-9 gene expression were studied by RT-PCR and confirmed with Western-blot. Levels of MMP-2 and MMP-9 in cell lysates were also quantified by ELISA assay. Results:Dose-dependent decrease in the migration of viable UM cells for primary and metastatic cell lines was observed (30-50 % inhibition). RT-PCR revealed dose-dependent down-regulation of gene expressions for MMP-2 and MMP-9 in all cell lines. This was confirmed by Western-blotting. ELISA assay revealed ~20-30% decrease in MMP-2 and MMP-9 protein content. Conclusions:DP inhibits primary and metastatic UM cell migration in vitro. Our data suggest that this inhibition of cell migration is mediated via down-regulation of MMP-2 and MMP-9 gene expression. DP may be a valuable adjunctive treatment modality for primary and metastatic UM in humans.

Keywords: melanoma • uvea • gene/expression