Reversible and irreversible tumor progression of a weakly malignant rat mammary carcinoma cell line by in vitro exposure to epidermal growth factor.
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- Published online on: January 1, 1998 https://doi.org/10.3892/ijo.12.1.197
- Pages: 197-399
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Abstract
We examined the effects of epidermal growth factor (EGF) on tumor progression of a weakly malignant rat mammary carcinoma cell line, ER-1. In vitro treatment with EGF enhanced tumorigenicity, metastatic capacity and in vitro invasive capacity of ER-1 cells. The increased malignancy of ER-1 cells was reversible, when the cells were pretreated with EGF for 24 h, whereas it was irreversible when pretreated with EGF for 1 month. EGF treatment elevated the intracellular peroxide level in ER-1 cells. When ER-1 cells were treated with EGF in the presence of N-acetylcysteine, a chemical antioxidant, the reversible or irreversible EGF-induced progression was inhibited. These results suggest that the reversible or irreversible tumor progression in ER-1 cells occur in accordance with the duration of exposure to EGF, and that reactive oxygen species may be involved in the progression.