title: Bryostatin 1 modulates the proliferation and lineage commitment of human myeloid progenitor cells exposed to recombinant interleukin-3 and recombinant granulocyte-macrophage colony-stimulating factor.
abstract: The activity of protein kinase C (PK-C) has been implicated in the regulation of the growth and differentiation of both normal and neoplastic hematopoietic cells. We have examined the effects of the PK-C-activating agents phorbol 12,13-dibutyrate (PDBu), mezerein, and bryostatin 1 on the proliferation and lineage commitment of CD34+ human myeloid progenitor cells stimulated by recombinant interleukin-3 (rIL-3) and/or recombinant granulocyte-macrophage colony-stimulating factor (rGM-CSF). Although each of the PK-C activators administered alone induced no colony formation, coadministration of these agents with plateau concentrations of each cytokine (eg, 50 ng/mL) increased the number of day 14 granulocyte-macrophage colony-forming units by 100% to 150%. The number of pure and mixed neutrophil and macrophage colonies was substantially enhanced in the presence of PK-C activators, whereas the percentage and, in most cases, the absolute number of eosinophilic colonies was significantly reduced. The inhibition of eosinophilic colony formation was not overcome by the addition of rIL-5. Although addition of bryostatin 1 24 hours before rIL-3 abrogated the increase in total colony formation observed with simultaneous administration of factors, the inhibition of eosinophilic colonies and the increase in neutrophil/macrophage colonies persisted under these conditions. The addition of bryostatin 1 for up to 144 hours after rIL-3 continued to potentiate total colony formation, whereas the inhibition of eosinophilic commitment was lost after 120 hours. Together, these results suggest that pharmacologic interventions at the level of PK-C may regulate both the proliferation as well as the lineage commitment of human hematopoietic progenitors exposed to rGM-CSF and rIL-3.
authors.affiliation: Division of Hematology/Oncology, Medical College of Virginia, Richmond.
authors.forename: F
authors.initials: F
authors.lastname: Li
authors.forename: S
authors.initials: S
authors.lastname: Grant
authors.forename: G R
authors.initials: GR
authors.lastname: Pettit
authors.forename: C W
authors.initials: CW
authors.lastname: McCrady
mesh_terms: D054713:Bryostatins; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D004224:Diterpenes; D004789:Enzyme Activation / Q000187:drug effects; D004804:Eosinophils / Q000166:cytology; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology*; D006098:Granulocytes / Q000166:cytology* / Q000187:drug effects; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000187:drug effects; D006801:Humans; D007377:Interleukin-3 / Q000494:pharmacology; D007783:Lactones / Q000494:pharmacology*; D018942:Macrolides; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology; D013729:Terpenes / Q000494:pharmacology
chemical_list: D054713:Bryostatins; D004224:Diterpenes; D007377:Interleukin-3; D007783:Lactones; D018942:Macrolides; D011994:Recombinant Proteins; D013729:Terpenes; C011309:mezerein; D015240:Phorbol 12,13-Dibutyrate; C046785:bryostatin 1; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D011493:Protein Kinase C