The Effect of Irradiation and Epidermal Growth Factor on Cell Cycle and Apoptosis Induction in Human Epithelial Tumor Cell Lines / 대한구강악안면방사선학회지

ABSTRACT

PURPOSE: This study was aimed to evaluate the cell cycle arrest and apoptosis induction after irradiation and epidermal growth factor(EGF) treatment in three human epithelial tumor cell lines(A431, Siha, KB). MATERIALS AND METHODS: Single irradiation of 2, 5 and 10 Gy was done on three cell lines with 5.38 Gy/min dose rate using Cs-137 irradiator at room temperature. Also, EGF of 10 ng/ml was added immediately after 10 Gy irradiation. Cell growth was evaluated by counting the living cell number using a hemocytometer at 1 day, 2 days, 3 days, 4 days and 5 days after irradiation. Cell cycle arrest and apoptosis induction were assayed with the flow cytometry at 8 hours, 12 hours, 1 day, 2 days, 3 days, 4 days and 5 days after irradiation. RESULTS: Growth of irradiated three cell lines were inhibited in proportion to radiation dose. EGF treatment after irradiation showed various results according to cell lines. On all cell lines, G2 arrest was detected after 8 hours and maximized after 12 hours or 1 day. Amount of G2 arrest was positively dose dependent. But, EGF showed no significant change on G2 arrest. G2 arrest was recovered with time at 2 Gy and 5 Gy irradiation. But, at 10 Gy irradiation, G2 arrest was continued. Apoptosis was detected at 10 Gy irradiation. On EGF treated group after irradiation, A431 and Siha cell lines showed slightly increased apoptosis but there was no statistically significant difference. KB cell line showed no marked change of apoptosis induction. CONCLUSION: Irradiation effects cell cycle arrest and apoptosis induction in three human epithelial tumor cell lines but epidermal growth factor doesn't effect change of cell cycle arrest and apoptosis induction.