The SCL gene product is regulated by and differentially regulates cytokine responses during myeloid leukemic cell differentiation.

Abstract

Differentiation induction in murine Ml leukemia cells by interleukin 6 (IL-6), leukemia inhibitory factor (LIF), and oncostatin M (OSM) is postulated to occur via a common receptor chain, gpl3O. In this study, growth factorinduced differentiation of Ml cells was accompanied by a late and persistent decrease in levels of mRNA and protein for a helix-oop-helix transcription factor, the SCL gene product. (18,(21)(22)(23). Despite differences in these receptor complexes, receptor signaling for IL-6, LIF, and OSM is postulated to occur via a common receptor chain (gpl3O) (24)(25)(26)(27).In the work reported here, we studied the behavior of SCL mRNA and protein during growth factor-induced differentiation of Ml leukemia cells. We then established M1/SCL cell The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.lines in which overexpression of SCL mRNA and protein was enforced. Using these M1/SCL cell lines, we examined the effects of SCL overexpression on terminal differentiation induced by LIF, IL-6, and OSM. MATERIALS AND METHODSEnforced Expression of SCL in Ml Cells. An SCL retrovirus was constructed by introducing the entire murine SCL coding region (28) into the MPZen/Neo retrovirus (29) so that SCL expression was under control of the long terminal repeat promoter of myeloproliferative sarcoma virus. Ml cells were then infected by cocultivation with an SCL-retroviral "packaging" cell line (30). After 3 days of cocultivation, cells were cloned in agar by selection with the neomycin analogue G418 (400 ,ug/ml). On day 7, individual G418-resistant colonies were resuspended to establish four M1/SCL clonal cell lines. M1/SCL clonal cell lines were confrmed to express the retroviral (exogenous) SCL mRNA (see below). Three control cell lines were obtained by using the vector alone; clonal cell lines derived by G418 selection in agar (M1/neo cell lines) were examined in addition to parental Ml cells. All cells were cultured in Dulbecco's modified Eagle's medium (DMEM) containing 10%6 bovine calf serum. At various time points cells were prepared for morphological examination (using Cytospin preparations stained with May-Grunwald and Giemsa reagents and examining a minimum of 200 cells) and Northern analysis, with medium being changed every 3 days during the culture period.Agar Cultures. Cells (300 per ml) were cultured with serial dilutions of purified recombinant mouse LIF, IL-6, or OSM in 35-mm Petri dishes using DMEM with a final concentration of 20% preselected bovine calf serum and 0.3% agar in a final volume of 1 ml. Cultures were incubated at 37°C in a fully humidified atmosphere of 10% CO2 in air. Colonies (clones of >40 cells) were scored at x 35 magnifications with a dissection microscope after 7 days of incubation. Differentiated colonies were identified by their characteristic dispersed morphology (31).Recloning experiments were performed by select...

Expression and function of members of the cytokine receptor superfamily on breast cancer cells

“…This result is notable, since OSM and LIF both utilize the LIFR-gp130 heterodimer for signalling, and at least in some situations elicit an identical biological response (Tanigawa et al, 1993). The di erence between OSM and LIF in MCF-7 cells may be attributable to an OSM-speci®c receptor subunit.…”

“…For IL-6 and IL-11 it appears that intracellular signalling is mediated via a homodimer of gp130 while LIF, OSM and CNTF utilise the heterodimer between LIF and gp130. Although signalling through these complexes is very similar, they can be distinguished in some systems (Tanigawa et al, 1993(Tanigawa et al, , 1995. These observations have provided a unifying concept to explain the biological redundancy of these growth-factors.…”

The CD2-scl transgene alters the phenotype and frequency of T-lymphomas in N-ras transgenic or p53 deficient mice

“…Gene targeting experiments have shown that scl is essential for the initiation of yolk sac haemopoiesis (Robb et al, 1995a;Shivdasani et al, 1995). In addition to this role in early haemopoiesis, experiments in tissue culture have provided evidence that scl is important at later stages of haemopoiesis for normal erythroid and monocytic lineage commitment and di erentiation (Green et al, 1991;Aplan et al, 1992;Tanigawa et al, 1993). Transcriptional regulation by scl may, in part, be controlled by the presence of scl-binding partners such as E12, E47 (Hsu et al, 1994) and LMO-2 (Valge-Archer et al, 1994;Wadman et al, 1994).…”

Cell growth and differentiation of a novel mouse Ito (fat-storing) cell line transformed by a temperature-sensitive mutant of simian virus 40

“…However, in ordinary primary culture, lipid droplets and vitamin A fluorescence disappear within several days when Ito cells are cultured without vitamin A. 11,17 In this study, oil-red O staining showed lipid droplets within the cells, and fluorescence microscopy examined by reverse-transcription PCR, whereas M1/SCL cells 12,13 (in which SCL expression is enhanced) served as positive control.…”