Thrombopoietin suppresses apoptosis and behaves as a survival factor for the human growth factor-dependent cell line, M07e.
Thrombopoietin (TPO) has been demonstrated to have proliferative effects on hematopoietic progenitor cells and maturational effects on more committed populations which express a megakaryocyte lineage-specific phenotype. M07e is a GM-CSF or interleukin 3 (IL-3)-dependent human leukemic cell line having surface markers characteristic of both myeloid progenitors and megakaryocytes. The effects of TPO on the proliferation and survival of M07e cells were investigated. Following an 18-h factor starvation period to remove residual growth factor signals and phase the cells in G0/G1, TPO provides a weak proliferative signal to M07e compared to IL-3 or GM-CSF treatment under the same conditions. However, TPO synergizes with both GM-CSF and IL-3, and to a greater extent with steel factor, a competence factor for M07e, in the induction of cellular proliferation. TPO sustains cellular integrity of M07e during prolonged (18 days) growth factor withdrawal and also protects M07e cells in serum-free conditions. In addition, preincubation of M07e for 72 h in TPO maintains its survival for subsequent cytokine-induced proliferation, while control media do not. TPO suppresses growth factor withdrawal-induced apoptosis as evaluated by flow cytometric detection of both in situ terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling and cellular DNA content via propidium iodide staining. These results suggest a role for TPO as a survival factor for M07e cells.
Ritchie
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A
Department of Microbiology/Immunology, Indiana University School of Medicine, Indianapolis 46202-5121, USA.
Vadhan-Raj
S
S
Broxmeyer
H E
HE
D017209:Apoptosis / Q000187:drug effects*; D001710:Biotin; D001798:Blood Proteins / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004249:DNA Damage; D003856:Deoxyuracil Nucleotides; D004357:Drug Synergism; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D006133:Growth Substances / Q000502:physiology; D006801:Humans; D007377:Interleukin-3 / Q000494:pharmacology; D007947:Leukemia, Megakaryoblastic, Acute; D015398:Signal Transduction / Q000187:drug effects; D013194:Staining and Labeling; D019089:Stem Cell Factor / Q000494:pharmacology; D013926:Thrombopoietin / Q000494:pharmacology*; D013997:Time Factors; D014407:Tumor Cells, Cultured / Q000166:cytology / Q000187:drug effects
D001798:Blood Proteins; D003856:Deoxyuracil Nucleotides; D006133:Growth Substances; D007377:Interleukin-3; D019089:Stem Cell Factor; D001710:Biotin; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D013926:Thrombopoietin