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 expres sion, leukotriene B-4 (LTB(4)) biosynthesis and glial fibrillary acidi c 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 [H-3]-thymidine incorporation and MTT ethylthiazol-2yl)-2 ,5-diphenyl-tetrazoliumbromide) assay, resulted in a time dependent de crease in [H-3]-thymidine incorporation into DNA and MTT-formazan form ation, respectively. The cell cycle regulation measured by flow cytome try with propidium iodide staining revealed that the cell multiplicati on cycle was slowed down due to accumulation of cells in S-phase of th e cell cycle, leading to inhibition in G(0)/G(1) phase of the cell cyc le. The 5-LO protein expression ((measured by Western immunoblot analy sis) and LTB(4) biosynthesis (measured by enzyme immunoassay) were fou nd to be increased by 2 to 2.4 fold and several fold respectively on d ays 3 and 4 of MuIFN-alpha/beta treatment. The GFAP protein expression wets also found to be increased at least by 3 fold on day 4 of the Mu IFN-alpha/beta treatment. These results suggest that inhibition in gro wth and thereby slowing of the cell multiplication cycle of glioma cel ls has resulted in upregulation of GFAP expression and 5-LO pathway.