title: Interleukin-1 stimulates proliferation of acute myeloblastic leukemia cells by induction of granulocyte-macrophage colony-stimulating factor release.
abstract: In this study, we further established the role of interleukin-1 (IL-1) alpha and IL-1 beta as regulators of proliferation of acute myeloid leukemia (AML) cells. IL-1 stimulated tritiated thymidine (3H-TdR) uptake of AML cells in 13 of 28 cases. Cytogenetic analysis confirmed the leukemic clonality of the IL-1-stimulated cells. Most likely, IL-1 exerted these stimulative effects directly on AML blast cells because IL-1 effectively induced 3H-TdR uptake of CD34-positive AML blasts (separated following cell sorting). Furthermore, adherent cell-depleted AML samples of three patients were more effectively stimulated than nondepleted AML fractions. Cluster and colony formation from adherent cell depleted AML samples could also be stimulated with IL-1, ie, in seven of ten cases analyzed. Subsequent experiments indicated that IL-1 stimulation depended on the release of GM-CSF because (1) induction of DNA synthesis of AML cells by IL-1 could be abrogated with antigranulocyte-macrophage colony-stimulating factor (GM-CSF) antibody, (2) conditioned media (CM) prepared from IL-1 stimulated AML blasts (adherent cell depleted) could stimulate the proliferation of purified normal bone marrow progenitors whereas supernatants from nonstimulated AML blasts did not, and (3) GM-CSF was demonstrated in IL-1/AML-CM with a specific radioimmunoassay, while GM-CSF was not detectable in nonstimulated supernatants. In one case of AML showing significant 3H-TdR uptake in the absence of CSFs, this spontaneous DNA synthesis was found to depend on autocrine IL-1 beta release as it could be suppressed with anti-IL-1 beta antibody or anti-GM-CSF. The blockade by anti-IL-1 beta could be overcome by the addition of high concentrations of IL-1 beta as well as GM-CSF. Thus, in this particular case, endogenously produced IL-1 beta had stimulated the release of GM-CSF which resulted in GM-CSF-dependent proliferation. The results indicate that GM-CSF production by AML blasts is often regulated by IL-1 rather than being constitutive.
authors.affiliation: Dr Daniel den Hoed Cancer Center, Rotterdam, The Netherlands.
authors.forename: R
authors.initials: R
authors.lastname: Delwel
authors.forename: C
authors.initials: C
authors.lastname: van Buitenen
authors.forename: M
authors.initials: M
authors.lastname: Salem
authors.forename: F
authors.initials: F
authors.lastname: Bot
authors.forename: S
authors.initials: S
authors.lastname: Gillis
authors.forename: K
authors.initials: K
authors.lastname: Kaushansky
authors.forename: B
authors.initials: B
authors.lastname: Altrock
authors.forename: B
authors.initials: B
authors.lastname: Löwenberg
mesh_terms: D002455:Cell Division; D003114:Colony-Forming Units Assay; D003115:Colony-Stimulating Factors / Q000096:biosynthesis* / Q000378:metabolism; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D006133:Growth Substances / Q000096:biosynthesis* / Q000378:metabolism; D006801:Humans; D007375:Interleukin-1 / Q000378:metabolism / Q000494:pharmacology*; D015470:Leukemia, Myeloid, Acute / Q000378:metabolism / Q000473:pathology*
chemical_list: D003115:Colony-Stimulating Factors; D006133:Growth Substances; D007375:Interleukin-1; D016178:Granulocyte-Macrophage Colony-Stimulating Factor