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Similar transforming growth factors (TGFs) produced by cells transformed by different isolates of feline sarcoma
Abstract:
Fisher rat embryo cells transformed by each of three independent isolates of feline sarcoma virus (FeSV) are shown to release transforming growth factors (TGFs) into cell culture medium. These acid- and heat-stable peptides compete for binding to, and stimulate phosphorylation of, EGF membrane receptors and promote anchorage-independent cell growth. Cells transformed by the Gardner and Synder-Theilen strains of FeSV produce high titers of TGF (60-200 ng eq EGF/liter) while cells transformed by McDonough FeSV produce TGF at only low levels (less than 10 ng eq EGF/liter). Growth factors produced by cells transformed by each of the three FeSV isolates functionally and biochemically resemble each other, mouse sarcoma growth factor (SGF), and TGFs produced by human tumor cells.
Insights
Feline sarcoma virus (FeSV) transformed cells release transforming growth factors (TGFs) that mimic EGF, promoting cell growth. Different FeSV strains yield varying TGF levels, but all share biochemical similarities.
Area of Science:
- Oncology
- Virology
- Cell Biology
Background:
- Feline sarcoma virus (FeSV) is known to induce tumors in felines.
- Understanding the mechanisms of FeSV-induced transformation is crucial for cancer research.
- Growth factors play a significant role in cell proliferation and cancer development.
Purpose of the Study:
- To investigate the production and characteristics of transforming growth factors (TGFs) released by FeSV-transformed rat cells.
- To compare the TGFs produced by different FeSV isolates.
- To assess the functional and biochemical properties of these TGFs in relation to EGF receptors and cell growth.
Main Methods:
- Culturing Fisher rat embryo cells transformed by three independent FeSV isolates.
- Measuring TGF titers in cell culture medium.
- Assessing the ability of TGFs to compete for EGF receptor binding and stimulate phosphorylation.
- Evaluating the effect of TGFs on anchorage-independent cell growth.
Main Results:
- All three FeSV isolates induced the release of TGFs into the cell culture medium.
- These TGFs are acid- and heat-stable peptides.
- The TGFs stimulate phosphorylation of EGF membrane receptors and promote anchorage-independent cell growth.
- Significant differences in TGF production titers were observed between FeSV strains (Gardner/Synder-Theilen vs. McDonough).
Conclusions:
- FeSV-transformed cells produce TGFs that exhibit properties similar to EGF.
- These TGFs contribute to the transformed phenotype by promoting anchorage-independent growth.
- The characterized TGFs share functional and biochemical similarities with other known TGFs, including those from human tumor cells.