Synergistic effect of targeting mTOR by rapamycin and depleting ATP by inhibition of glycolysis in lymphoma and leukemia cells

• Published in: Leukemia Vol. 19; no. 12; pp. 2153 - 2158
• Main Authors: XU, R.-H, PELICANO, H, ZHANG, H, GILES, F. J, KEATING, M. J, HUANG, P
• Format: Journal Article
• Language: English
• Published: London Nature Publishing 01.12.2005; Nature Publishing Group
• Subjects: Adenosine Triphosphate - antagonists & inhibitors; Apoptosis; Apoptosis - drug effects; ATP; Biological and medical sciences; Cancer; Cell growth; Cell Proliferation - drug effects; Cytarabine - pharmacology; Cytotoxicity; Depletion; Drug Synergism; Energy; Energy metabolism; Energy Metabolism - drug effects; Glucose; Glycolysis; Glycolysis - drug effects; Hematologic and hematopoietic diseases; Humans; Inhibition; Kinases; Leukemia; Leukemia - drug therapy; Leukemia - metabolism; Leukemia - pathology; Leukemias. Malignant lymphomas. Malignant reticulosis. Myelofibrosis; Lymphoma; Lymphoma - drug therapy; Lymphoma - metabolism; Lymphoma - pathology; Medical sciences; Metabolism; Phosphorylation; Protein Kinases - drug effects; Rapamycin; Respiration; Sirolimus - pharmacology; Synergistic effect; TOR protein; TOR Serine-Threonine Kinases; Toxicity; Tumor Cells, Cultured; United States > US; Protein kinase mTOR; Drug combination; synergy; Targeting; Hematology; Sirolimus; Leukemia; Lactone; Malignant hemopathy; Metabolism; Macrolide; Lymphoma; Synergism; Macrocycle; Lymphoproliferative syndrome; ATP metabolism; Glycolysis; Inhibitor; ATP; rapamycin
• ISSN: 0887-6924; 1476-5551
• DOI: 10.1038/sj.leu.2403968

The mammalian target of rapamycin (mTOR) pathway plays important roles in regulating nutrient metabolism and promoting the growth and survival of cancer cells, which exhibit increased glycolysis for ATP generation. In this study, we tested the hypothesis that inhibition of the mTOR pathway and glycolysis would synergistically impact the energy metabolism in cancer cells and may serve as an effective therapeutic strategy to kill malignant cells. Using human lymphoma cells and leukemia cells, we demonstrated that the combination of rapamycin, an mTOR inhibitor, with a glycolytic inhibitor produced synergistic cytotoxic effect, as evidenced by apoptosis and cell growth inhibition assays. Mechanistic studies showed that inhibition of the mTOR pathway by rapamycin alone sufficiently suppressed the phosphorylation of the downstream molecules p70S6K and 4E-BP-1, but only caused a moderate cytostatic effect. Combination of mTOR inhibition and blockage of glycolysis synergistically suppressed glucose uptake and severely depleted cellular ATP pools, leading to significant enhancement of cell killing. In contrast, combination of rapamycin and ara-C did not increase cytotoxicity in vitro. Our findings suggest that targeting mTOR pathway in combination with inhibition of glycolysis may be an effective therapeutic strategy for hematological malignancies. This mechanism-based drug combination warrants further investigation in preclinical and clinical settings.