Spermidine/spermine N(1)-acetyltransferase activity associates with white blood cell count in myeloid leukemias

The metabolism of polyamines, the cationic small molecules essential for cell proliferation and differentiation, is altered in cancer cells and can be exploited in cancer diagnosis and therapy. Spermidine/spermine N(1)-acetyltransferase (SSAT), which regulates intracellular levels of polyamines by catabolizing spermidine and spermine, has a controversial role in the development of cancers. In this study, the polyamine metabolism and function of SSAT were characterized in acute myeloid leukemia (AML), chronic myeloid leukemia (CML), and acute lymphoid leukemia patient samples. Also, mice overexpressing SSAT and having a myeloproliferative phenotype were analyzed for their response to decitabine and histone deacetylase inhibitor trichostatin A. The presence of epigenetic factors in the bone marrow cells of SSAT mice was analyzed. Elevated levels of spermidine and spermine, as well as increased activity of SSAT, were detected in AML, CML, and acute lymphoid leukemia patients compared with the controls. However, we found SSAT activity to be associated with white blood cell count only in AML and CML patients. Decitabine treatment brought the peripheral blood and bone marrow cell counts of SSAT mice to the level of wild-type mice. Spermidine/spermine N(1)-acetyltransferase mice had increased histone methylation and an increased level of histone deacetylase 1 in their bone marrow cells. The study suggests that SSAT influences the development of myeloid malignancies, and epigenetic factors partly contribute to the SSAT overexpression-induced myeloproliferative disease in mice.