Dual-targeting of aberrant glucose metabolism in glioblastoma

Abstract

BackgroundGlioblastoma (GBM) is the most common and malignant primary brain tumor. In contrast to some other tumor types, aberrant glucose metabolism is an important component of GBM growth and chemoresistance. Recent studies of human orthotopic GBM in mice and in situ demonstrated GBM cells rely on both glycolysis and mitochondrial oxidation for glucose catabolism. These observations suggest that the homeostasis of energy metabolism of GBM cells might be further disturbed by dual-inhibition of glucose metabolism. The present study aimed to evaluate the efficacy and the mechanisms of dual-targeting therapy in GBM cells.MethodsRepresentative GBM cells (immortalized GBM cell lines and patient-derived GBM cells) and non-cancerous cells were treated with 4-(N-(S-penicillaminylacetyl)amino) phenylarsonous acid (PENAO), an in-house designed novel arsenic-based mitochondrial toxin, in combination with dichloroacetate (DCA), a pyruvate dehydrogenase kinase inhibitor. The efficacy of this combinatorial therapy was evaluated by MTS assay, clonogenic surviving assay and apoptotic assays. The underlying mechanisms of this dual-targeting treatment were unraveled by using mitochondrial membrane potential measurements, cytosol/mitochondrial ROS detection, western blotting, extracellular flux assay and mass spectrometry.ResultsAs monotherapies, both PENAO and DCA induced proliferation arrest in a panel of GBM cell lines and primary isolates. PENAO inhibited oxygen consumption, induced oxidative stress and depolarized mitochondrial membrane potential, which in turn activated mitochondria-mediated apoptosis. By combining DCA with PENAO, the two drugs worked synergistically to inhibit cell proliferation (but had no significant effect on non-cancerous cells), impair the clonogenicity, and induce mitochondria-mediated apoptosis. An oxidative stress of mitochondrial origin takes a prominent place in the mechanism by which the combination of PENAO and DCA induces cell death. Additionally, PENAO-induced oxidative damage was enhanced by DCA through glycolytic inhibition which in turn diminished acid production induced by PENAO. Moreover, DCA treatment also led to an alteration in the multidrug resistance (MDR) phenotype of GBM cells, thereby leading to an increased cytosolic accumulation of PENAO.ConclusionsThe findings of this study shed a new light with respect to the dual-targeting of glucose metabolism in GBM cells and the innovative combination of PENAO and DCA shows promise in expanding GBM therapies.

Sensitization of Glioblastoma Cells to Irradiation by Modulating the Glucose Metabolism

“…We found that concurrent use of dichloroacetate with radiotherapy indeed prevented the increase in glycolytic rate observed following radiotherapy alone. Our previous study demonstrated that dichloroacetate effectively induced a dose-dependent proliferation arrest of in vitro cultures of glioblastoma cells but had no significant effect on noncancerous cells (15). This result is in line with most of the studies that investigated the efficacy of dichloroacetate demonstrating that a therapeutic window exists although suprapharmacologic level of dichloroacetate (5-50 mmol/L) is necessary to halt the growth of cancer cells in vitro (9,32,33,35).…”

“…Protein concentration was measured using BCA Assay Kit (Pierce). Proteins (50 mg/sample) were separated via reducing 10% SDS-PAGE, and standard Western blotting procedures (15) were used to detect proteins of interest with the following primary antibodies: g-H2AX (Cell Signaling Technology, CST #9718), HIF1a (CST, #3716), PDK-1 (CST, #3820), and b-actin (Abcam, ab8227). Images and densitometry were acquired by using ImageQuant TL software.…”

Targeting cancer stem‐like cells in glioblastoma and colorectal cancer through metabolic pathways

“…It is important to mention that all patents received standard of care therapy (Temozolomide and radiation) . DCA continues to be a promising anti‐cancer agent as a study showed that it sensitizes GBM cells to radiotherapy by inducing a G2‐M phase cell‐cycle arrest, reducing mitochondrial reserve capacity and increasing DNA damage …”

The Biological Activity of Sodium Dichloroacetate and Its Effectiveness During the Experimental Clinical Studies

“…В работе [41] на клеточных линиях глиобласто-мы (U87, U251, LN229, DBTRG) изучалась эффек-тивность комбинированного применения НДХА и PENAO -мышьяксодержащего митохондриально-го токсина, подавляющего потребление кислорода и индуцирующего ОС и деполяризацию мембран митохондрий, приводя к запрограммированной клеточной гибели. НДХА, в свою очередь, пода-вляет гликолиз и продукцию кислот, вызванную PENAO, а также ингибирует экспрессию протеина MRP1, что ведет к увеличению накопления PENAO в цитозоле.…”