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Abstract
The stem cells of acute myeloid leukemia (AML) are the malignancy initiating cells whose survival ultimately drives growth of these lethal diseases. Here we review leukemia stem cell (LSC) biology, particularly as it relates to the very heterogeneous nature of AML and to its high disease relapse rate. Leukemia ontogeny is presented, and the defining functional and phenotypic features of LSCs are explored. Surface and metabolic phenotypes of these cells are described, particularly those that allow distinction from features of normal hematopoietic stem cells (HSCs). Opportunities for use of this information for improving therapy for this challenging group of diseases is highlighted, and we explore the clinical needs which may be addressed by emerging LSC data. Finally, we discuss current gaps in the scientific understanding of LSCs.
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Affiliation(s)
| | - Upendarrao Golla
- Division of Hematology and Oncology, Department of Medicine, Pennsylvania State University College of Medicine, Hershey, PA, USA
- Penn State Cancer Institute, Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Arati Sharma
- Division of Hematology and Oncology, Department of Medicine, Pennsylvania State University College of Medicine, Hershey, PA, USA
- Penn State Cancer Institute, Pennsylvania State University College of Medicine, Hershey, PA, USA
- Department of Pharmacology, Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - David F Claxton
- Division of Hematology and Oncology, Department of Medicine, Pennsylvania State University College of Medicine, Hershey, PA, USA.
- Penn State Cancer Institute, Pennsylvania State University College of Medicine, Hershey, PA, USA.
- Division of Hematology and Oncology, Penn State Cancer Institute, Cancer Institute, Next-Generation Therapies, 500 University, Hershey, PA, 17033, USA.
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Freedman ML, Cohen HS, Rosman J, Forte FJ. Ferritin and sideroblastic anaemias: inhibition of protein synthesis by protease contaminants in commercial preparations of ferritin. Br J Haematol 1976; 32:579-87. [PMID: 1259940 DOI: 10.1111/j.1365-2141.1976.tb00962.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Commercial preparations of ferritin inhibited reticulocyte-lysate cell-free protein synthesis and disaggregated polyribosomes to monoribosomes and ribosomal subunits. These effects were prevented by addition of reduced glutathione (GSH) to the incubation medium, but ferritin did not lower GSH concentration in the lysates. The more purified the ferritin preparation, the less inhibition of protein synthesis was observed. These data suggested that the effect was due to a contamination of the ferritin with proteolytic activity. In confirmation of this proposal we demonstrated that there was protease activity in both the 2X and 5X crystalized ferritin preparations, with 2.5 times greater activity in the 2X preparation. The proteolytic activity in ferritin was inhibited by incubation with the protease inhibitor tosyl lysine chloromethyl ketone (TLCK). When an amount of trypsin equivalent to the protease activity of the ferritin was added to the incubation mixture, similar effects on protein synthesis and the ribosome-polyribosome component were found. Both GSH and TLCK prevented these effects of trypsin. These data suggest that the previously reported effect of ferritin on reticulocyte cell-free protein synthesis was due to contamination of the ferritin by a protease. It appears that ferritin does not play a direct role in the pathogenesis of sideroblastic anaemias.
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