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Inhibition of mitogenic activity of PDGF, EGF, and FGF by interferon-gamma
1Memorial Sloan-Kettering Cancer Center, New York, New York 10021.
Abstract:
Natural or recombinant human interferon-gamma abolishes the mitogenic activity of platelet-derived growth factor, epidermal growth factor, and fibroblast growth factor on GM2767 or FS-4 human fibroblasts. Similarly murine interferon-gamma abolishes the mitogenic activity of these growth factors on BALB/C-3T3 fibroblasts. Inhibition of DNA synthesis by interferon-gamma was accomplished by blocking the transition of G0/G1 to S phase of the cell cycle. Addition of interferon-gamma 15 h after the addition of growth factors (when the cells had already entered the S phase) had no effect on DNA synthesis.
Insights
Interferon-gamma (IFN-γ) halts fibroblast proliferation by blocking cell cycle entry, but does not affect cells already synthesizing DNA. This suggests IFN-γ specifically targets early cell cycle progression.
Area of Science:
- Cell biology
- Immunology
- Molecular biology
Background:
- Growth factors like PDGF, EGF, and FGF stimulate fibroblast proliferation.
- Interferon-gamma (IFN-γ) is a cytokine with diverse biological activities.
- Fibroblast proliferation is a key process in tissue repair and development.
Purpose of the Study:
- To investigate the effect of interferon-gamma on the mitogenic activity of specific growth factors on human and murine fibroblasts.
- To determine the mechanism by which interferon-gamma inhibits fibroblast proliferation.
- To identify the specific phase of the cell cycle affected by interferon-gamma.
Main Methods:
- Treatment of GM2767, FS-4, and BALB/C-3T3 fibroblasts with human or murine interferon-gamma.
- Addition of platelet-derived growth factor (PDGF), epidermal growth factor (EGF), and fibroblast growth factor (FGF).
- Monitoring of DNA synthesis and cell cycle progression.
Main Results:
- Interferon-gamma abolished the mitogenic activity of PDGF, EGF, and FGF on both human and murine fibroblasts.
- Interferon-gamma inhibited DNA synthesis by blocking the G0/G1 to S phase transition in the cell cycle.
- Addition of interferon-gamma after cells entered the S phase had no effect on DNA synthesis.
Conclusions:
- Interferon-gamma effectively inhibits growth factor-induced fibroblast proliferation.
- The inhibitory effect of interferon-gamma is cell cycle-dependent, specifically targeting the G0/G1 to S phase transition.
- Interferon-gamma's mechanism involves preventing cells from initiating DNA synthesis.