Reversible and irreversible tumor progression of a weakly malignant rat mammary carcinoma cell line by in vitro exposure to epidermal growth factor

• Published in: International journal of oncology Vol. 12; no. 1; p. 197
• Main Authors: Nagayasu, H, Hamada, J, Nakata, D, Shibata, T, Kobayashi, M, Hosokawa, M, Takeichi, N
• Format: Journal Article
• Language: English
• Published: Greece 01.01.1998
• Subjects: Acetylcysteine - pharmacology; Adenocarcinoma - pathology; Animals; Disease Progression; DNA Damage - drug effects; DNA Primers - chemistry; Epidermal Growth Factor - pharmacology; ErbB Receptors - genetics; ErbB Receptors - metabolism; Female; Flow Cytometry; Free Radical Scavengers - pharmacology; In Vitro Techniques; Mammary Neoplasms, Experimental - pathology; Microscopy, Confocal; Neoplasm Invasiveness; Oxidative Stress - drug effects; Peroxides - metabolism; Rats; Rats, Inbred SHR; Reverse Transcriptase Polymerase Chain Reaction; Tumor Cells, Cultured - drug effects
• ISSN: 1019-6439
• 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.