Journal ArticleDOI
Transforming growth factors (TGFs): Properties and possible mechanisms of action
George J. Todaro,Joseph E. De Larco,Charlotte M. Fryling,Patricia A. Johnson,Michael B. Sporn +4 more
TLDR
The term "autocrine secretion" has been proposed for this type of situation where a cell secretes a hormone-like substance for which it has external cell membrane receptors and may provide a partial explanation for some aspects of tumor cell progression.Abstract:
Transforming growth factors (TGFs) are growth-promoting polypeptides that cause phenotypic transformation and anchorage-independent growth of normal cells. They have been isolated from several human and animal carcinoma and sarcoma cells. One TGF is sarcoma growth factor (SGF) which is released by murine sarcoma virus-transformed cells. The TGFs interact with epidermal growth factor (EGF) cell membrane receptors. TGFs are not detectable in culture fluids from cells which contain high numbers of free EGF cell membrane receptors. SGF acts as a tumor promoter in cell culture systems and its effect on the transformed phenotype is blocked by retinoids (vitamin A and synthetic analogs). The production of TGFs by transformed cells and the responses of normal cells to the addition of TGFs to the culture medium raise the possibility that cells "autostimulate" their own growth by releasing factors that rebind at the cell surface. The term "autocrine secretion" has been proposed for this type of situation where a cell secretes a hormone-like substance for which it has external cell membrane receptors. The autocrine concept may provide a partial explanation for some aspects of tumor cell progression.read more
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Mitogenic stimulation of human breast cancer cells in a growth factor-defined medium: Synergistic action of insulin and estrogen
Bart van der Burg,Gerard R. Rutteman,Marinus A. Blankenstein,Siegfried W. de Laat,Everardus J.J. van Zoelen +4 more
TL;DR: It is concluded that MCF7 cells require insulin (or insulin‐like growth factors) for proliferation, and at suboptimal insulin concentrations, E2 acts synergistically with insulin, possibly by inducing autocrine production of polypeptide growth factors by these cells.
Journal ArticleDOI
Bone marrow stromal cell lines with lymphopoietic activity express high levels of a pre-B neoplasia-associated molecule
TL;DR: It is proposed that the 6C3 antigen-bearing molecule may play a role in stromal cell-dependent, pre-B cell proliferation, as well as in neoplastic proliferation of pre- B leukemias.
Journal Article
Presence of Transforming Growth Factors in Human Breast Cancer Cells
David S. Salomon,James A. Zwiebel,Mozeena Bano,Ilona Losonczy,Paula Fehnel,William R. Kidwell +5 more
TL;DR: Concentrated CM from a human mammary carcinoma cell line, MCF-7, and ten individual clones derived from these cells was found to stimulate the anchorage-independent growth of normal rat kidney cells in soft agar and to inhibit the binding of epidermal growth factor (EGF) to mouse NIH/3T3 fibroblasts
Journal ArticleDOI
BALB and Kirsten murine sarcoma viruses alter growth and differentiation of EGF-dependent balb/c mouse epidermal keratinocyte lines.
TL;DR: BALB or Kirsten murine sarcoma viruses are acute transforming retroviruses, which have been shown to transform fibroblastic and hematopoietic cells, and can rapidly confer upon epithelial keratinocytes in culture growth properties that resemble those of malignant epidermoid carcinoma cells.
Journal ArticleDOI
Effects of SV40 transformation on the cytoskeleton and behavioural properties of human keratinocytes.
TL;DR: SVK14 cells can be grown in the absence of 3T3 feeders and show an impaired ability to differentiate into squames, and this impairment becomes more marked with passage, but at later passages the cells acquire the ability to form colonies in agar and to produce a factor with mitogenic activity which stimulates DNA synthesis in quiescent3T3 cells.
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