Nutrient-dependent arrest of fibroblast growth is partially reversed by insulin but not fibroblast growth factor

Kamely, Daphne; Rudland, Philip S.

doi:10.1038/260051a0

Cited by 29 publications

(7 citation statements)

References 18 publications

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“…The process of endocytosis could itself by stimulatory or could serve to deliver large quantities of precipitate components-including PPi, Pi, Ca2 +, or M$+ (Table 1)-to the cytoplasm. All but the first of these components have been suggested to have growthregulatory roles (e.g., Holley and Kiernan, 1974;Kamely and Rudland, 1976;Whitfield et al, 1973;Rubin, 1975). The results reported here argue against this possibility since very little endocytosis of PP; precipitate occurs.…”

Section: -Egf and 22 I-pdgf Binding To 3t3contrasting

confidence: 56%

Growth stimulatory precipitates of CA²⁺ and pyrophosphate

Bowen‐Pope

Rubin

1983

Journal Cellular Physiology

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Inorganic pyrophosphate (PPi) forms an insoluble precipitate with calcium in growth medium when its concentration exceeds about 0.1 mM. This PPi precipitate can reproduce the effects of 10% calf serum on all cell processes examined in Balb/c 3T3 cells, including hexose uptake and metabolism to lactate, 3H-uridine, and 3H-choline uptake, and the incorporation of 3H-leucine and 3H-thymidine into trichloroacetic acid (TCA)-insoluble material. Concentrations of PPi insufficient to form a precipitate are without effect on cell metabolism. The precipitates are most effective when prepared with concentrations of PPi just sufficient to result in precipitate formation and become considerably less effective as the PPi concentration increases, even though the quantity of precipitate formed continues to increase with PPi concentration up to 1 mM PPi. Precipitates formed at low PPi concentrations consist largely of Ca2+ (81% of cations), PPi (77% of anions), and Pi (23% of anions). Precipitates formed with higher concentrations of PPi contain proportionately less Ca2+ and Pi and more monovalent cations and PPi. We have distinguished cell surface-bound PPi from intracellular PPi by differential extraction. The quantity of surface-bound PPi increases sharply when the PPi concentration reaches the point of precipitate formation. If the precipitate is prevented from binding to the cell surface by inverting monolayer cultures in precipitate-containing medium, the cells are not stimulated. These findings suggest that the binding of PPi precipitate to the cell surface is involved in the stimulation of cell metabolism by PPi. PPi precipitates do not absorb serum mitogens or inhibitors from the culture medium, nor do they affect the binding of 125I-platelet-derived growth factor to its specific cell-surface receptor, suggesting that PPi precipitates do not act directly through either of these mitogen-receptor systems. In analogy to cell stimulation by epidermal growth factor and by antigens, we suggest that PPi may be active only in the form of a precipitate because multivalent binding of receptors with formation of clusters is required for stimulation. The inhibitory effects of high concentrations of PPi may be due to interference by free PPi with formation of active receptor clusters.

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Section: -Egf and 22 I-pdgf Binding To 3t3contrasting

confidence: 56%

Growth stimulatory precipitates of CA²⁺ and pyrophosphate

Bowen‐Pope

Rubin

1983

Journal Cellular Physiology

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“…The physiological role of insulin in mammary growth and development is unclear (22). But its requirement in tissue culture at near physiological concentrations with a pituitary hormone and hydrocortisone for maximum increases in DNA synthesis may reflect a requirement for maintenance of cell homeostasis through a supply of various nutrients (14).…”

Section: Discussionmentioning

confidence: 99%

Mitogenic activity of pituitary hormones on cell cultures of normal and carcinogen-induced tumor epithelium from rat mammary glands

Ps¹,

Hallowes²,

Durbin³

et al. 1977

The Journal of Cell Biology

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Cell suspensions containing normal or tumor epithelium were readily obtained by enzymatically digesting rat mammary glands from perphenazine-treated (prolactin-hypersecreting) cycling, female virgin animals or hormone-responsive mammary tumors from animals treated with dimethylbenzanthracene. Cell suspensions were fractionated into predominantly epithelial and predominantly stromal cells by their differential rates of attachment to culture dishes. Both normal mammary and tumor epithelial cells were characterized by the presence of specific celljunctional complexes, desmosome-like structures, surface microvilli, and their ability to synthesize casein. Serum-dependent protease activity was greater in cultures derived from tumors, and cells from such cultures grew in agarose whereas those from the non-neoplastic gland did not. The addition of prolactin to the culture medium stimulated DNA synthesis in primary or secondary epithelial cultures from tumors, whereas additional insulin and hydrocortisone with prolactin were required for similar levels of DNA synthesis in cultures from nonneoplastic glands. The fraction of cells synthesizing DNA was, however, smaller than that with 10% serum measured in the same time period. Both growth hormone and epidermal growth factor stimulated DNA synthesis but to a lesser extent than did prolactin. Prolactin with hydrocortisone and insulin was relatively inactive in promoting DNA synthesis of the nonepithelial cells whereas pituitary fibroblast growth factor was more active. These mitogenic effects were obtained when the hormones were added to the medium at near physiological concentrations, and paralleled the known activities of the hormones in control of mammary gland growth and development in the rat.Growth and development of the mammary gland in mice and rats occur mainly by a process of cell multiplication rather than by hypertrophy of existing cellular units (9). The hormones which control this process in vivo have largely been identified by means of a series of endocrine gland-ablation and hormone-replacement experiments, and they include prolactin, growth hormone together with estrogens, glucocorticoids, and progesterone (18,21,34,35). In organ culture, however, Topper and others have failed to show any mitogenic effect of prolactin or growth hormone although high, nonphysiological concentrations of insulin and a corticoid were shown to stimulate thymidine incorporation into DNA (19,22,33,38,40). Since pretreatment of virgin mice with prolactin

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“…Six different nutrient-deficient media containing dialyzed fetal calf serum were initially screened for their ability to induce G1 arrest of proadipocytes. These media were deficient in P04 (16), glutamine and histidine (16,17), cysteine and methionine (16)(17)(18), 99% of all amino acids (17,18), seven selected amino acids and glucose (19), or isoleucine (12). Only isoleucine-deficient medium containing dialyzed 10% fetal calf serum both induced G1 arrest and supported proadipocyte viability for the 21-day interval required to perform these experiments.…”

Section: Methodsmentioning

confidence: 99%

“…In selected experiments low-density GN-arrested cells, prepared as above, were refed complete DME medium containing 30% human platelet-poor-plasma-derived serum (PPP-S [16][17][18] days. Fig.…”

Section: Methodsmentioning

confidence: 99%

Coupling of growth arrest and differentiation at a distinct state in the G1 phase of the cell cycle: GD.

Scott¹,

Florine²,

Wille³

et al. 1982

Proc. Natl. Acad. Sci. U.S.A.

165

108

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The differentiation of most mammalian cells is preceded by growth arrest in the G1 phase of the cell cycle, but the characteristics of this state have not been established. We now report that the growth arrest that precedes the differentiation of BALB/c 3T3 T mouse proadipocytes must occur at a distinct state in G1 designated GD. GD-arrested cells are characterized by their ability to differentiate in the absence of DNA synthesis and by their unique sensitivity to the mitogenic effect of isobutylmethylxanthine. Proadipocytes induced to become G1 growth arrested at other states by culture in medium deficient in growth factor or nutrients, by contrast, are unable to differentiate in the absence of DNA synthesis and are not stimulated to proliferate by isobutylmethylxanthine even when they are exposed to differentiationpromoting medium prior to arrest. These data support the conclusion that, prior to the expression of a differentiated phenotype, proadipocytes must arrest their growth at a distinct state in the G1 phase of the cell cycle, GD. These data also provide the basis for the hypothesis that carcinogenesis is associated with defects in the coupling of growth arrest and differentiation at the GD state.Regulation of cell proliferation of many cell types is mediated by the, coupling of growth arrest and differentiation. In vivo studies on hematopoietic cells (1) and epithelial cells of the skin (2) and in vitro studies on other cell types (3) have established this fact. Although there is considerable controversy concerning the mechanisms that serve to initiate the differentiation process (4), the available evidence suggest growth arrest in the G1 phase of the cell cycle precedes expression of the differentiated phenotype. It has, however, not been established whether growth arrest occurs at a distinct state in G1 prior to differentiation. This question is of critical importance if the metabolic events that control the coupling of growth arrest and differentiation are to be established and if defects in the coupling process that may be associated with various disease states, such as aging and carcinogenesis, are to be identified. In this paper we report on the first of our studies, which show that, prior to differentiation, proadipocytes arrest their growth at a state in the G1 phase of the cell cycle (GD) that is distinct from the G1 growth arrest states induced by deprivation of growth factor or serum (Gs) or by deprivation of nutrients (GN).MATERIALS AND METHODS Cell Culture, Cell Proliferation, and Cell Differentiation. The proadipocyte cell line, designated 3T3 T, derived from BALB/c 3T3 (A31) mouse embryo cells by L. Diamond (5), was grown at 37°C in a 5% CO2 humidified atmosphere in Dulbecco's modified Eagle's medium (DME medium) containing 10% heat inactivated fetal calf serum unless otherwise stated.All stock cultures were grown in antibiotic-free medium; experimental specimens, however, were cultured in medium supplemented with penicillin (100 units/ml) and streptomycin (100 ,ug/ml). Cells wer...

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Nutrient-dependent arrest of fibroblast growth is partially reversed by insulin but not fibroblast growth factor

Cited by 29 publications

References 18 publications

Growth stimulatory precipitates of CA²⁺ and pyrophosphate

Growth stimulatory precipitates of CA²⁺ and pyrophosphate

Mitogenic activity of pituitary hormones on cell cultures of normal and carcinogen-induced tumor epithelium from rat mammary glands

Coupling of growth arrest and differentiation at a distinct state in the G1 phase of the cell cycle: GD.

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Nutrient-dependent arrest of fibroblast growth is partially reversed by insulin but not fibroblast growth factor

Cited by 29 publications

References 18 publications

Growth stimulatory precipitates of CA2+ and pyrophosphate

Growth stimulatory precipitates of CA2+ and pyrophosphate

Mitogenic activity of pituitary hormones on cell cultures of normal and carcinogen-induced tumor epithelium from rat mammary glands

Coupling of growth arrest and differentiation at a distinct state in the G1 phase of the cell cycle: GD.

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Growth stimulatory precipitates of CA²⁺ and pyrophosphate

Growth stimulatory precipitates of CA²⁺ and pyrophosphate