Strong Correlation between the Expression Levels of HDAC4 and SIRT6 in Hematological Malignancies of the Adults

Histone deacetylase enzymes, confirmed to have important role in the pathogenesis of leukemia, are promising targets of epigenetic treatment. However, in acute myeloid leukemia, our knowledge on their expression levels is limited, and controversial data have been published about their potential oncogenic or tumorsuppressor properties in solid tumors. In our study, the expression levels of HDAC4 and SIRT6 were evaluated via Western blot analysis in 45 bone marrow samples (2 uninfiltrated and 43 concerned by different kinds of hematological malignancies), including 32 specimens obtained from patients with newly diagnosed AML. Significantly higher HDAC4 level was detected in case of FLT3-ITD mutation compared to the group of patients without carrying this mutation (p < 0.05). Compared to the non-infiltrated samples, the expression level of HDAC4 in AML M5 patients has been proved to be significantly higher (p < 0.05). Decreasing expression levels of both HDAC4 and SIRT6 were observed during the induction treatment of FAB M5 type AML. Strong correlation has been proved between the expression levels of HDAC4 and SIRT6 (r = 0.722 in full cohort and r = 0.794 in AML), that confirms the recently suggested cooperation between NAD⁺-independent and NAD⁺-dependent HDAC enzymes in leukemia.