Growth-promoting alpha-globulin

Michl, J; Spurná, Věra

doi:10.1016/0014-4827(74)90379-6

Cited by 12 publications

(1 citation statement)

References 8 publications

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“…Fractions to be tested were solubilized in culture medium (centrifuged if necessary to eliminate unsoluble mate-rial) and added on quiescent CEF culture in the presence of 100 pg alpha globulin, a seric protein (Cohn Fraction IV), which has properties of growth factors (Michl and Spurna, 1974).…”

Section: Assays Of Idf45 Activitymentioning

confidence: 99%

Modulation by the src oncogene of the effect of inhibitory diffusible factor IDF45

Blat

Villaudy

Rouillard

et al. 1987

Journal Cellular Physiology

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Density-dependent inhibition of growth has been assumed to be under the control of inhibitory molecules diffusing from dense cell cultures. Growth inhibitory factors have been fractionated or purified from medium conditioned by different cell types. In the present work, it was shown that IDF45 (inhibitory factor diffusing from 3T3 cells) decreased DNA synthesis in chick embryo fibroblasts (CEF) and was an inhibitor of CEF growth; this inhibition was reversible. Since similitudes between oncogene products and growth factors have been observed, it was of interest to compare the inhibitory effect of IDF45 upon the stimulation of DNA synthesis induced either by serum or by pp60-src. CEF infected by Ny68 virus (a mutant of Rous sarcoma virus ts for the expression of transformation) were density-inhibited at 41 degrees C, but were stimulated at this temperature by addition of 1% serum. This stimulation was 94% inhibited by IDF45. The same Ny68-infected cells could also be stimulated by transfer to 37 degrees C, the permissive temperature (in the absence of serum). The stimulation of DNA synthesis by src expression was poorly inhibited by IDF45. From our results, it appears that oncogene expression in CEF induces a loss in their sensitivity to IDF45. This would explain why transformed cells escape DDI of growth.

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Section: Assays Of Idf45 Activitymentioning

confidence: 99%

Modulation by the src oncogene of the effect of inhibitory diffusible factor IDF45

Blat

Villaudy

Rouillard

et al. 1987

Journal Cellular Physiology

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Fibronectin is not a serum spreading factor for HeLa cells

Michl

Baudysová

Sochorová

et al. 1983

Cell Biochemistry & Function

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The spreading of HeLa cells on plastic substratum is mediated by fibronectin-depleted foetal calf serum but not by fibronectin isolated by gelatin-Sepharose affinity chromatography. The same is true for freshly explanted chick embryonic chondrocytes. In contrast, BHK cell spreading exceeds 67% after 120 min at 37 degrees C in fibronectin-supplemented (10 micrograms ml-1) serum-free medium. Long-term cultivation of HeLa cells in Eagle's MEM supplemented with fibronectin-free serum is associated with the accumulation of cells in mitosis or before cytokinesis; many cells die and the remaining living cells, characterized by marked changes in morphology, multiply very slowly. It can be concluded therefore that fibronectin does not produce spreading in HeLa cells but forces them into mitosis.

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Density‐dependent inhibition of growth: Inhibitorydiffusible factors from 3T3‐ and rous sarcoma virus (RSV)‐transformed 3T3 cells

Harel

Chatelain

Golde

1984

Journal Cellular Physiology

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We recently fractionated, from the culture medium of 3T3 cells, a thermolabile inhibitory diffusible factor (IDFN) with a molecular weight of about 40,000 daltons, which decreased nucleic acids synthesis of stimulated target 3T3 cells. In the present publication the inhibitory activities of IDFN (produced by 3T3 cells) and IDFT (produced by RSV-transformed 3T3 [3T3 SRA/H] cells) on 3T3 and 3T3 SRA/H cells have been compared. The inhibitory activity of IDFN decreased (by a mean of 57%) when it was tested on transformed instead of 3T3 cells. On the other hand, IDFT was able to decrease 14C-inosine incorporation in target 3T3 cells. However, the inhibitory activity of IDFT decreased (by mean 50%) when tested on 3T3 SRA/H instead of 3T3 cells. Therefore, transformed cells produced an inhibitory factor but were less sensitive than 3T3 cells to its inhibitory activity. The inhibitory activity of IDFT on 3T3 SRA/H cells was only 20% of the inhibitory activity of IDFN on 3T3 cells. This appreciable difference is of particular interest, since it could explain the release of density-dependent inhibition of growth (DDI) in transformed 3T3 SRA/H cells. Furthermore, it provides more evidence for the hypothesis that, in 3T3 cells, DDI of growth is due to the release of an inhibitory molecule into the medium, and that IDFN is in fact, the inhibitory molecule involved in this phenomenon.

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Growth-promoting alpha-globulin

Cited by 12 publications

References 8 publications

Modulation by the src oncogene of the effect of inhibitory diffusible factor IDF45

Modulation by the src oncogene of the effect of inhibitory diffusible factor IDF45

Fibronectin is not a serum spreading factor for HeLa cells

Density‐dependent inhibition of growth: Inhibitorydiffusible factors from 3T3‐ and rous sarcoma virus (RSV)‐transformed 3T3 cells

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