Modulation of glioma cell growth and 5-lipoxygenase expression by interferon.

The effect of mouse interferon-alpha/beta (MuIFN-alpha/beta on growth/viability, cell cycle regulation, 5-lipoxygenase (5-LO) protein expression, leukotriene B4 (LTB4) biosynthesis and glial fibrillary acidic protein (GFAP) expression of mouse glioma (G-26) cells in vitro was studied. The G-26 cells were treated with 800 IU/ml of MuIFN-alpha/beta for 1, 2, 3 and 4 days. The growth and viability of glioma cells was evaluated by [3H]-thymidine incorporation and MTT (3(4,5-dimethylthiazol-2yl)-2,5-diphenyl-tetrazoliumbromi de) assay, resulted in a time dependent decrease in [3H]-thymidine incorporation into DNA and MTT formazan formation, respectively. The cell cycle regulation measured by flow cytometry with propidium iodide staining revealed that the cell multiplication cycle was slowed down due to accumulation of cell in S-phase of the cell cycle, leading to inhibition in G0/G1 phase of the cell cycle. The 5-LO protein expression (measured by Western immunoblot analysis) and LTB4 biosynthesis (measured by enzyme immunoassay) were found to be increased by 2 to 2.4 fold and several fold respectively on days 3 and 4 of MuIFN-alpha/beta treatment. The GFAP protein expression was also found to be increased at least by 3 fold on day 4 of the MuIFN-alpha/beta treatment. These results suggest that inhibition in growth and thereby slowing of the cell multiplication cycle of glioma cells has resulted in upregulation of GFAP expression and 5-LO pathway.