Effect of sodium butyrate on pro-matrix metalloproteinase-9 and -2 differential secretion in pediatric tumors and cell lines

Matrix metalloproteinases (MMPs) are enzymes responsible for extracellular matrix degradation and contribute to local and distant cell invasion during cancer progression or metastasis. The effects of chromatin structure on gene expression and the use of histone deacetylase inhibitors such as sodium butyrate (NaBu) may directly influence pro-MMPs secretion. In the present study, we evaluated the effect of NaBu on pro-MMP-9 and pro-MMP-2 secretion in human Jurkat and HT1080 cells, and in 36 pediatric solid tumors. Cell lines and samples were exposed to 8 mM of NaBu and proteinase activity was evaluated in the supernatant by gelatin zymograms. Our results showed, for Jurkat cells treated with NaBu, increases of 2-fold and 1.5-fold in pro-MMP-9 and pro-MMP-2 secretion, respectively. A 50% decrease in pro-MMP-9 secretion due to NaBu was observed in HT1080 cells. NaBu induced a 0.62 reduction in levels of pro-MMP-9 secretion in untreated tumors. For cell lines and some NaBu-treated tumors we found histone H4 hyperacetylation. We conclude that pro-MMPs gene expression and their secretion can be epigenetically mis-regulated in tumoral processes.