TITLE:
Dichloroacetic Acid (DCA)-Induced Cytotoxicity in Human Breast Cancer Cells Accompanies Changes in Mitochondrial Membrane Permeability and Production of Reactive Oxygen Species
AUTHORS:
Zeiyad Alkarakooly, Surya P. Kilaparty, Qudes A. Al-Anbaky, Mohammad Saeed Khan, Nawab Ali
KEYWORDS:
Breast Cancer, Dichloroacetic Acid, DCA, Cancer Therapy, Anticancer Agents, Apoptosis, Mitochondrial Defects, Reactive Oxygen Species (ROS)
JOURNAL NAME:
Journal of Cancer Therapy,
Vol.5 No.13,
November
17,
2014
ABSTRACT: Cancer cells utilize cytosolic
glycolysis for their energy production even in the presence of adequate levels
of oxygen (Warbug effect) due to mitochondrial defects. Dichloroacetic acid
(DCA) shifts cytosolic glucose metabolism to aerobic oxidation by inhibiting
mitochondrial pyruvate dehydrogenase kinase (PDK) and increasing pyruvate
uptake. Therefore, DCA has potential in reversing the glycolytic metabolism
defect in cancerous cells. DCA is also known to induce apoptosis in a number of
cancer cell lines, the mechanism of which is not well understood. In this
study, an attempt has been made to investigate the effects of DCA on aggressive
human breast cancer (MCF-7) cells as compared with less aggressive mouse
osteoblastic (MC3T3) cells. Cell cytotoxicity was determined by MTT, crystal
violet and Trypan blue exclusion assays. Western blot was used to detect any
changes in the expression of apoptotic markers. Flow cytometry was used to
measure apoptotic and necrotic effects of DCA. Mitochondrial integrity was
determined by change in mitochondrial membrane potential (Δψm), whereas
oxidative damage was determined by production of reactive oxygen species (ROS).
DCA caused a concentration-dependent cytotoxicity both in MCF-7 and MC3T3 cell
lines. MCF-7 cells were most affected. Flow cytometry results showed a
significantly higher apoptosis in MCF-7 even at lower concentrations of DCA. However,
higher concentrations of DCA were necrotic. Western blotting showed an
increased expression of Mn-SOD-1 upon DCA treatment. Further, DCA decreased Δψm
and increased ROS production. The effects of DCA were more pronounced on MCF-7
cells as compared to MC3T3 cells. Our results suggest that DCA-induced
cytotoxicity in cancerous cells is mediated via changes in Δψm and production
of ROS.