Reversible and irreversible tumor progression of a weakly malignant rat mammary carcinoma cell line by in vitro exposure to epidermal growth factor.
- Authors: H Nagayasu, J Hamada, D Nakata, T Shibata, M Kobayashi, M Hosokawa, N Takeichi
Published online on: Thursday, January 1, 1998
- Pages: 197-399
- DOI: 10.3892/ijo.12.1.197
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.