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Production of transforming growth factors by simian sarcoma virus-transformed cells

E J van Zoelen, M A van Rooijen, T M van Oostwaard

    Cancer Research
    |March 15, 1987
    PubMed

    Insights

    Simian sarcoma virus (SSV) transformation of rat kidney cells causes loss of growth factor dependence and reduced growth factor binding. These SSV-transformed cells secrete high levels of transforming growth factor alpha (TGF-α) and TGF-β, inducing phenotypic transformation.

    Area of Science:

    • Cell Biology
    • Virology
    • Molecular Biology

    Background:

    • Normal rat kidney (NRK) cells require external polypeptide growth factors for proliferation.
    • Simian sarcoma virus (SSV) is known to cause cellular transformation.

    Purpose of the Study:

    • To investigate the effects of SSV transformation on NRK cell growth factor requirements and production.
    • To determine the role of transforming growth factors (TGFs) in SSV-induced cellular transformation.

    Main Methods:

    • Comparison of growth factor binding and proliferation in SSV-transformed versus non-transformed NRK cells.
    • Analysis of conditioned medium from SSV-transformed NRK cells for secreted growth factors.
    • Assessment of TGF-α and TGF-β's ability to induce phenotypic transformation in NRK cells.

    Main Results:

    • SSV-transformed NRK cells exhibit a complete loss of requirement for external growth factors.
    • SSV-transformed NRK cells show significantly reduced binding of platelet-derived growth factor and epidermal growth factor.
    • SSV-transformed NRK cells secrete high levels of both TGF-α and TGF-β.
    • Combined TGF-α and TGF-β are sufficient to induce phenotypic transformation in NRK cells.

    Conclusions:

    • While sis oncogene expression is crucial for SSV-induced transformation, additional gene expression may be necessary for complete phenotypic alterations.
    • Secreted TGFs play a significant role in the phenotypic transformation of NRK cells by SSV.

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