Metabolic effects of acute thiamine depletion are reversed by rapamycin in breast and leukemia cells
| Autor: | Mignon A. Keaton, Jeffrey A. Moscow, Sumitra Miriyala, Craig T. Jordan, Daret K. St. Clair, Christina M. Wiedl, Shuqian Liu |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2014 |
| Předmět: |
Hydrolases
Gene Expression Biochemistry Energy-Producing Processes Hematologic Cancers and Related Disorders chemistry.chemical_compound Mice Drug Discovery Breast Tumors Thiamine Protein Metabolism chemistry.chemical_classification Multidisciplinary Antibiotics Antineoplastic Leukemia Obstetrics and Gynecology Hematology Precursor Cell Lymphoblastic Leukemia-Lymphoma Pyruvate dehydrogenase complex Acute Lymphoblastic Leukemia Oxygen Metabolism Enzymes Oncology MCF-7 Cells Carbohydrate Metabolism Medicine Oncology Agents Female Metabolic Pathways Growth inhibition Intracellular Research Article Drugs and Devices Drug Research and Development Cell Survival Science Mice Nude Breast Neoplasms Transketolase Biology Bioenergetics Amino Acids Aromatic Leukemias Breast Cancer medicine Genetics Animals Humans Nutrition Sirolimus Cofactors Cancers and Neoplasms Thiaminase medicine.disease Xenograft Model Antitumor Assays Enzyme Metabolism chemistry Amino Acids Branched-Chain |
| Zdroj: | PLoS ONE, Vol 9, Iss 1, p e85702 (2014) PLoS ONE |
| ISSN: | 1932-6203 |
| Popis: | Thiamine-dependent enzymes (TDEs) control metabolic pathways that are frequently altered in cancer and therefore present cancer-relevant targets. We have previously shown that the recombinant enzyme thiaminase cleaves and depletes intracellular thiamine, has growth inhibitory activity against leukemia and breast cancer cell lines, and that its growth inhibitory effects were reversed in leukemia cell lines by rapamycin. Now, we first show further evidence of thiaminase therapeutic potential by demonstrating its activity against breast and leukemia xenografts, and against a primary leukemia xenograft. We therefore further explored the metabolic effects of thiaminase in combination with rapamycin in leukemia and breast cell lines. Thiaminase decreased oxygen consumption rate and increased extracellular acidification rate, consistent with the inhibitory effect of acute thiamine depletion on the activity of the TDEs pyruvate dehydrogenase and 2-oxoglutarate dehydrogenase complexes; these effects were reversed by rapamycin. Metabolomic studies demonstrated intracellular thiamine depletion and the presence of the thiazole cleavage product in thiaminase-treated cells, providing validation of the experimental procedures. Accumulation of ribose and ribulose in both cell lines support the thiaminase-mediated suppression of the TDE transketolase. Interestingly, thiaminase suppression of another TDE, branched chain amino ketoacid dehydrogenase (BCKDH), showed very different patterns in the two cell lines: in RS4 leukemia cells it led to an increase in BCKDH substrates, and in MCF-7 breast cancer cells it led to a decrease in BCKDH products. Immunoblot analyses showed corresponding differences in expression of BCKDH pathway enzymes, and partial protection of thiaminase growth inhibition by gabapentin indicated that BCKDH inhibition may be a mechanism of thiaminase-mediated toxicity. Surprisingly, most of thiaminase-mediated metabolomic effects were also reversed by rapamycin. Thus, these studies demonstrate that acute intracellular thiamine depletion by recombinant thiaminase results in metabolic changes in thiamine-dependent metabolism, and demonstrate a previously unrecognized role of mTOR signaling in the regulation of thiamine-dependent metabolism. |
| Databáze: | OpenAIRE |
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