Effect of Interferon-γ on ACNU-induced DNA Damage and Cytotoxicity in Human Glioblastoma Cells

Interferons (IFNs) are a natural body defense with powerful effects on tumor growth, including gliomas. The direct effects of IFN-γ on (1-4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU)-induced deoxyribonucleic acid (DNA) damage and cytotoxicity were investigated in two human glioblastoma cell lines, A-172 and T98G, using a single cell microgel electrophoresis technique and a microculture tetrazolium assay. The results demonstrated a synergistic effect of IFN-γ with ACNU on intracellular damage in both cell lines. 10μg/ml ACNU induced a cell inhibition rate of 23.9% in A-172 cells, and almost no effect on T98G cells. 1000 U/ml IFN-γ and 10 μg/ml ACNU caused a significant increase in cell inhibition, 51.2% for A-172 and 72.3% for T98G cells. DNA damage in individual A-172 and T98G cells exposed to ACNU was enhanced significantly by IFN-γ (p < 0.001). The findings suggest a direct effect of IFN-γ on ACNU-induced cell damage in human glioma, in addition to its effect on immunomodulation.