Dysregulation of Metabolic Genes May Be Normalized by Epigenetic Drugs (Vorinostat, Decitabine) and Nutritional Compounds (Genistein, Vitamin D) in Leukemic Cells.

Dysregulation of energy metabolism is a key feature of malignancy and known to be regulated by epigenetic mechanisms. This study explores gene expression in the KG1 cell line and a primary culture of leukemic blasts from a patient, both incubated with SAHA (suberoyl anilide hydroxamic acid, also known as Vorinostat) in comparison to other epigenetic drugs such as Decitabine (DAC) but also nutritional compounds such as genistein and vitamin D3 with a known activity on metabolism where epigenetic mechanisms play a role.

Following a 3 days incubation with pharmacologic concentrations of the above mentioned compounds, gene expression patterns of the KG1 cell-line were analysed on an Affymetrix Gene Expression Array and specifically evaluated by quantitative real time PCR from KG1 cells and primary leukemic cells of a patient with an AML-M2 which were cultured at the same conditions as the KG1 cells. In order to confirm epigenetic mechanisms induced by targeted drugs, methylation patterns of selected tumor suppressor genes were analyzed using specific primers for bisulfite-treated DNA.

Our experiments show that expression of a large scale of micro RNAs which are known to be responsible for alternative splicing is stimulated by SAHA as well as DAC and to a lesser extent also Vitamin D3 and genistein, but downregulation of mitochondrial RNAs as a consequence of apoptosis was exclusively observable by SAHA.

HDAC-inhibition results in clear repression of metabolic genes involved in glycolysis (5/6 genes) as well as cholesterol-biosynthesis (14/15 genes) and fatty acid synthesis (all 4 genes) which are also known to be regulated by nutrition. Classic tumour suppressor genes, transcription factors and cell-cycle regulators such as P53, P15, P16 and P21 and FOXO were (re-) activated with this treatment while MYC was down-regulated.

A downregulation and thus normalization of a large scale of genes including key genes from malignancy-associated stimulation of glycolysis as well as biosynthesis of cholesterol and fatty acids was observed with SAHA and nutritional compounds such as Vitamin D and genistein. We propose that these interactions should be carefully considered in clinical application, and a combination of synergistic drugs and/or dietary strategies may provide a major advantage in future drug development.

Supported by Jubilaeumsfonds der Oesterreichischen Nationalbank.

No relevant conflicts of interest to declare.