In vitro activity: DCA can trigger apoptosis of human lung, breast and brain cancer cells. Cancer cells shows increased levels of ROS, depolarization of the MMP in vitro and increased apoptosis both in vitro and in vivo after DCA treatment. DCA inhibits the activity of pyruvate dehydrogenase kinase (PDK), thereby stimulating the mitochondrial enzyme pyruvate dehydrogenase (PDH). When turned off, PDH no longer converts pyruvate to acetyl-CoA required for mitochondrial respiration and glucose dependent oxidative phosphorylation. DCA shifts cellular metabolism from glycolysis to glucose oxidation, decreasing the mitochondrial membrane potential gradient and helping to open mitochondrial transition pores. This metabolic switch facilitates translocation of pro-apoptotic mediators like cytochrome c (cyt c) and apoptosis inducing factor (AIF), both of which stimulate apoptosis. DCA thus drives cancer cells to commit suicide by apoptosis.

Kinase Assay: Dichloroacetate (CPC-211; DCA; X-11S) is a potent and specific inhibitor of pyruvate dehydrogenase kinase (PDK) with IC50 values of 183 and 80 μM for PDK2 and PDK4 respectively.

Cell Assay: In order to assess cell viability, cells are plated in 96 well plates at a density of 3000 cells per well and 8 wells per group. Following exposure to DCA and ATO for 24 to 72 hours, cells are incubated for 3 hours with neutral red (30 μg/ml) in fresh media, then washed with PBS, followed by the addition of lysis buffer (acetic acid/methanol, 80%/20%) and the absorbance at 540 nm is recorded. Results are expressed as mean ± S.D, calculations are performed using the Prism software package, ANOVA with Tukey post test was applied and P < 0.05 was considered to be statistically significant.