Effect of the histone deacetylase inhibitor trichostatin a in human peripheral blood lymphocytes as a function of donor age.

The histone deacetylase inhibitor trichostatin A (TSA) is a promising agent for the treatment of certain types of cancers alone or in synergistic combination with other anticancer agents. One of the advantages of the use of histone deacetylase inhibitors, such as TSA, is that its effects have been found to be more potent toward cancer cells compared to normal cells. The effect of anticancer agents on the immune system, and on lymphocytes in particular, is of major importance to the success of anticancer regimens. In this respect, information documenting the effect of such agents on normal lymphocytes compared to malignant cells may be of significant value for the successful designing of clinical protocols. Moreover, the parameter of age may be a factor in the differential effects of such protocols. Histone deacetylase inhibitors lead to the accumulation of acetylated histones and, depending on the cell type, may induce either apoptosis, cell cycle arrest, or differentiation. Previous work from our lab has shown that TSA induces the accumulation of histone H4 acetylation and apoptosis in human peripheral blood lymphocytes. In light of the above, we have extended our investigation of the effects of TSA on human lymphocytes to include the parameter of age, which has not been previously studied. Our results show that TSA induces apoptosis of lymphocytes from donors of all age groups, but no age-related changes in the levels of apoptosis are observed.