Regulation of gene expression by tumor promoters. II. Control of cell shape and developmental programs for macrophages and granulocytes in human myeloid leukemic cells

Abstract

Regulation of the developmental programs for macrophages and granulocytes has been analysed, using two-dimensional gel electrophoresis of the cytoplasmic protein changes, in a human myeloid leukemic cell line (HL60) that can be induced to differentiate to macrophages by the macrophage and granulocyte-inducing (MGI) protein and the tumor promoter 12-0-tetradecanoyl-phorbol-13-acetate (TPA), and to granulocytes by dimethylsulfoxide (DMSO). Studies on the protein changes induced by the different inducers showed a similar developmental program for macrophage differentiation induced by MGI or TPA, which differed from the beginning from the granulocyte program induced by DMSO. Comparison with normal cells from human peripheral blood has shown that the develop mental programs induced in the HL60 cells are relevant to the normal programs of differentiation for these two cell types. Unlike MGI and DMSO, TPA induces rapid attachment of the HL60 cells t o the surface of the Petri dish. Combined treatment with TPA and DMSO showed cell attachment, extensive spreading of the cells, the regulation of specific proteins and expression of the macrophage program. The addition of TPA t o cells induced for the granulocyte program by DMSO resulted in cell attachment and spreading and a switchover from the granulocyte t o the macrophage program. The results indicate that cells in suspension can express either the macrophage or granulocyte program depending on the inducer, and that changes in cell shape associated with cell attachment induced by TPA can regulate specific proteins and restrict the developmental program to macrophages. It is suggested that the in vivo environment of cells in relation t o the possibilities for cell adhesion, which can be regulated by tumor promotors, may play a major role in determining the developmental program of myeloid and other cell types.Normal myeloblasts exposed to the appropriate macrophage and granulocyte-inducing (MGI) protein, can be induced to differentiate to macrophages or granulocytes (Ginsburg and Sachs, 1963; Sachs, 1965, 1966;Ichikawa et al., 1966;Sachs, 1974Sachs, , 1978Sachs, , 1980 Lotem etal., 1980). The ability to differentiate to these two cell types has also been found in clones of myeloid leukemic cells (Paran et al., 1970;Sachs, 1974Sachs, , 1978Sachs, , 1980Lotem et al., 1980) and can be regulated in appropriate clones by different inducers (Lotem and Sachs, 1974;Sachs, 1978;Falk and Sachs, 1980). Thus, cells of the human myeloid leukemic cell line HL60 (Collins et al., 1977(Collins et al., , 1978 can be induced to differentiate to macrophages by MGI (Lotem and Sachs, 1979) and tumor-promoting phorbol esters including 12-0-tetradecanoylphorbol-13-acetate (TPA) (Lotem and Sachs, 1979;Rovera et al., 1979) that act via MGI (Lotem and Sachs, 1979), and to granulocytes by dimethylsulfoxide (DMSO) (Collins et al., 1978).The two different cell types have been identified by their cell morphology (Collins et al., 1978;Lotem and Sachs, 1979), some enzymes (Rovera et al., Vorbrodt et a...

CCAAT/Enhancer Binding Protein α Is a Regulatory Switch Sufficient for Induction of Granulocytic Development from Bipotential Myeloid Progenitors

“…Moreover, if ectopic C/EBP␣ was induced and allowed to be expressed for a sufficient time (7 days), TPA treatment accelerated granulocytic maturation. This observation suggests that C/EBP␣ is a particularly powerful differentiation factor, as it has been shown that HL-60 cells which had been treated for 5 days with DMSO to induce granulocytic cells could be still differentiated to macrophages by subsequent treatment with TPA (43). One possible explanation could be that C/EBP␣ expression affects the expression of other factors fundamental for granulocytic maturation which FIG.…”

Early growth response gene 1 stimulates development of hematopoietic progenitor cells along the macrophage lineage at the expense of the granulocyte and erythroid lineages

“…These observations led to the conclusion that cytokine-regulated cell adhesion plays a major role in determining the developmental program of myeloid progenitor cells. 31 In accordance with this idea, it is possible that Egr-1 target genes that encode for or regulate expression of cell-surface adhesion proteins play a crucial role in the remarkable ability of Egr-1 to divert the development of progenitors from other myeloid lineages toward macrophage differentiation.…”

“…31 These protein changes did not occur on induction of HL-60 granulocytic differentiation by dimethyl sulfoxide (DMSO). The same set of protein changes was also observed in normal human peripheral blood monocytes after attachment to the surface of tissue-culture plates and was not observed in human peripheral blood granulocytes, 31 indicating the relevance of the observed changes in protein expression to normal myelopoiesis. Furthermore, using this set of protein changes as a diagnostic tool, we showed that HL-60 cells treated with both TPA and DMSO attached and underwent even more rapid macrophage differentiation than cells treated with TPA alone.…”

Electrophoretic analysis of the cytoplasmic and nuclear protein changes after induction of differentiation in WEHI‐3B myelomonocytic leukemia cells

“…Similar electrophoretic analyses of the initial protein changes in other cell lines capable of undergoing differentiation have, however, often shown many fewer changes, eg, myoblasts showed 30 protein changes [B], murine embryonic cells showed 36 changes on induction of development [ 191, and Friend erythroleukemia cells showed only 11 protein changes [20]. Rapid changes in a small number of proteins have also been reported after treatment of epithelial cells with hydrocortisone [21], fibroblasts with platelet-derived growth factor [22], and the human promyeloblastic leukemia HL-60 treated with dimethyl sulfoxide [23]. The discrepancy in the number of protein changes induced in M1 cells compared with other induction systems suggests that either disparate criteria have been used for the scoring of protein changes, or that there is an intrinsic difference between M1 cells and other leukemic cell systems (eg, perhaps related to the presence of C-type viruses in MI cells) [24].…”