Effect of transformation of chicken cells by Rous sarcoma virus on in vitro phosphorylation of nuclear non-histone proteins

Blat, C.; Harel, L; Villaudy, J.; Golde, A

doi:10.1016/0014-4827(81)90469-9

Cited by 14 publications

(3 citation statements)

References 18 publications

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“…Cells Primary cultures of chick embryo fibroblasts were prepared from 10-day-old brown Leghorn chick embryos and were cultured at 37°C in modified Eagle's medium supplemented with antibiotics and 5% calf serum as described (Blat et al, 1981).…”

Section: Methodsmentioning

confidence: 99%

Insulin‐like growth factor binding protein (IGFBP‐3), an inhibitor of serum growth factors other than IGF‐I and ‐II

Liu

Delbé

Blat

et al. 1992

Journal Cellular Physiology

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Our results show that an insulin-like growth factor binding protein, IGFBP-3, purified from rat serum, is an inhibitor of chick embryo fibroblast (CEF) growth. It abolished DNA synthesis in CEF stimulated by IGF-I as well as by human serum. Rat IGFBP-3 and IDF45 (an inhibitory diffusible factor secreted by mouse cells) had the same activities, confirming that they have an intrinsic capacity to inhibit serum stimulation and may be considered as growth inhibitors. Our data show that inhibition by IGFBP-3 of serum stimulation was not simply the result of its inhibition of IGF present in the serum: 1) While anti-IGF-I IgG was able to completely inhibit stimulation induced by added IGF-I, it did not decrease stimulation induced by 1% human serum. Anti-IGF-II IgG inhibited the stimulation induced by added IGF-II, but only 25% decreased the stimulation induced by 0.7% serum. The percent inhibition was not significantly increased when the concentration of serum was decreased to 0.2%, which induced 140% stimulation of DNA synthesis; 2) stimulation by 0.2% serum was much more inhibited by IGFBP-3 than by IgG anti IGF-II; 3) after separation of IGF-I and IGF-II from serum by chromatography of acidified serum proteins on BioGel P150, the remaining serum proteins (with a molecular mass greater than 45 kDa) which were depleted in IGF-I and -II (verified by RIA determination) still stimulated DNA synthesis, and this stimulation was 80% inhibited by IGFBP-3.

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Section: Methodsmentioning

confidence: 99%

Insulin‐like growth factor binding protein (IGFBP‐3), an inhibitor of serum growth factors other than IGF‐I and ‐II

Liu

Delbé

Blat

et al. 1992

Journal Cellular Physiology

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“…Cells were grown in modified Eagle's medium supplemented with antibiotics and 5% newborn calf serum in a CO2 incubator at 370C, as previously described (20).…”

Section: Cell Culturementioning

confidence: 99%

In vivo proteolysis of serum insulin-like growth factor (IGF) binding protein-3 results in increased availability of IGF to target cells.

Blat¹,

Villaudy²,

Binoux³

1994

J. Clin. Invest.

173

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IGF Binding Protein-3 (IGFBP-3), the major IGF carrier in the blood, undergoes limited proteolysis which reduces its affinity for IGFs, thus facilitating dissociation. The functional effects of this at the cellular level were studied by comparing two serum pools, one from healthy adults, one from women during late pregnancy when IGFBP-3 proteolysis is increased. Sera were mixed to yield identical IGF-I and IGF-II concentrations in the two pools. Western ligand and immunoblotting gave the characteristic IGFBP patterns for the two types of serum. Both pools dose-dependently stimulated DNA synthesis in cultured chick embryo fibroblasts. Stimulation by pregnancy serum was twice that by normal serum at 0.05-0.2% concentrations (P < 0.001). In the presence of excess monoclonal anti-IGF-I and -II antibodies, stimulation by both (0.1-0.2%) pools was 70-80% reduced and residual stimulation was similar. Addition of recombinant human (rh)IGFBP-3 dose-dependently depressed both pools' activity, more so for normal serum at 25 and 50 ng/ml, equally for each at 100 ng/ml. At the latter concentration, slight proteolysis of the rhIGFBP-3 was detectable in the presence of 0.2% pregnancy serum, but at 25 ng/ml, proteolysis was absent. These results suggest that IGFs are released more readily from pregnancy serum, accounting for the weaker inhibitory effect of low rhIGFBP-3 concentrations. For identical IGF concentrations, pregnancy serum's greater biological activity therefore reflects greater IGF availability to the cells. This study demonstrates the functional consequences at cellular level of serum IGFBP-3 proteolysis, underlining its significance in regulating serum IGF bioavailability. (J. Clin.

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“…Primary cultures of chick embryo fibroblasts (CEF) were prepared from 10-day-old brown Leghorn chick embryos and were cultivated at 37°C in Eagle's medium supplemented with antibiotics and 5% newborn calf serum as described (Blat et al, 1981).…”

Section: Cellsmentioning

confidence: 99%

An IGF binding protein is an inhibitor of fgf stimulation

Villaudy

Delbé

Blat

et al. 1991

Journal Cellular Physiology

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We purified to homogeneity a growth inhibiting diffusible factor (IDF45) secreted by dense cultures of mouse 3T3 cells and which was able to inhibit 100% of DNA synthesis stimulated by serum in chick embryo fibroblasts (CEF) (Blat et al., 1989a). We then demonstrated that this factor was an IGF-binding protein (Blat et al., 1989b). Indeed, its N-terminal amino acid sequence was homologous to that of rat IGFBP-3. Our present results show that basic fibroblast growth factor (bFGF) induced, respectively, a fivefold and threefold increase in DNA synthesis in mouse embryo fibroblasts (MEF) and CEF. IDF-45 inhibited the stimulation induced by bFGF by about 65%, while stimulation induced by insulin, PDGF, or EGF was only weakly or not at all inhibited by IDF45. When bFGF stimulation was determined in the presence of a high concentration of insulin in conditions which minimize the effect of endogenous IGF-I or -II, this stimulation was decreased by about 50% in the presence of IDF45. This result suggests that addition of bFGF stimulates IGF secretion, thereby resulting in partial loss of inhibition, by IDF45, of bFGF stimulation.

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Effect of transformation of chicken cells by Rous sarcoma virus on in vitro phosphorylation of nuclear non-histone proteins

Cited by 14 publications

References 18 publications

Insulin‐like growth factor binding protein (IGFBP‐3), an inhibitor of serum growth factors other than IGF‐I and ‐II

Insulin‐like growth factor binding protein (IGFBP‐3), an inhibitor of serum growth factors other than IGF‐I and ‐II

In vivo proteolysis of serum insulin-like growth factor (IGF) binding protein-3 results in increased availability of IGF to target cells.

An IGF binding protein is an inhibitor of fgf stimulation

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