Histone deacetylase inhibition results in a common metabolic profile associated with HT29 differentiation

Abstract

Cell differentiation is an orderly process that begins with modifications in gene expression. This process is regulated by the acetylation state of histones. Removal of the acetyl groups of histones by specific enzymes (histone deacetylases, HDAC) usually downregulates expression of genes that can cause cells to differentiate, and pharmacological inhibitors of these enzymes have been shown to induce differentiation in several colon cancer cell lines. Butyrate at high (mM) concentration is both a precursor for acetyl-CoA and a known HDAC inhibitor that induces cell differentiation in colon cells. The dual role of butyrate raises the question whether its effects on HT29 cell differentiation are due to butyrate metabolism or to its HDAC inhibitor activity. To distinguish between these two possibilities, we used a tracer-based metabolomics approach to compare the metabolic changes induced by two different types of HDAC inhibitors (butyrate and the non-metabolic agent trichostatin A) and those induced by other acetyl-CoA precursors that do not inhibit HDAC (caprylic and capric acids). [1,2-13C2]-d-glucose was used as a tracer and its redistribution among metabolic intermediates was measured to estimate the contribution of glycolysis, the pentose phosphate pathway and the Krebs cycle to the metabolic profile of HT29 cells under the different treatments. The results demonstrate that both HDAC inhibitors (trichostatin A and butyrate) induce a common metabolic profile that is associated with histone deacetylase inhibition and differentiation of HT29 cells whereas the metabolic effects of acetyl-CoA precursors are different from those of butyrate. The experimental findings support the concept of crosstalk between metabolic and cell signalling events, and provide an experimental approach for the rational design of new combined therapies that exploit the potential synergism between metabolic adaptation and cell differentiation processes through modification of HDAC activity.

A key role for transketolase-like 1 in tumor metabolic reprogramming

“…Glutamine quantification was achieved by converting it to glutamate using glutaminase (Sigma-Aldrich). The isotopologue distribution of glucose, lactate, RNA ribose, glutamate and fatty acids after incubation with [1,2- 13 C 2 ]-D-glucose (Isotec) was analyzed by GC-MS as described [54, 55] using a Shimadzu GCMS-QP2010 system (Duisburg, Germany).…”

“…1 μL of the derivatized product was loaded to a GC-2010 gas chromatograph (Shimadzu) equipped with a HP-5MS capillary column (30 m length, 250 μm diameter and 0.25 μm film thickness), connected to a GCMSQP2010 mass selective detector (Shimadzu) [54]. Lactate was extracted from the medium by ethyl acetate after acidification with HCl and 1 mL ethyl acetate at 20°C.…”

Tracer-based metabolomics: Concepts and practices

“…It is clear that these molecular mechanisms and small molecules are parts of the cellular metabolic network [60, 61]. The workings of these mechanisms and small molecules are constrained by their sharing enzymes, substrates and co-factors with other reactions of the network.…”

Metabolic Pathways as Targets for Drug Screening

“…On the other hand, MIA cells had a high pentose synthesis phenotype which was corrected when they were treated with oxythiamine. (15) We have recently used phenotypic phase plane analysis to show that inhibition of histone acetylation by genetic intervention or by chemical inhibitor of the reaction had similar metabolic phenotypes (25). Panel (ii) shows result of treatment A which is orthogonal to the phenotypic phase plane of X and Y.…”