Abstract
Purpose: :
To evaluate the effects of bevacizumab on expression of Bcl-2, Bcl-XL and apoptosis in retinal pigment epithelial (RPE) cells under oxidative stress.
Methods: :
RPE cells were treated with H2O2 (50,100,200,300,400µM) and bevacizumab at or above the dose normally used in clinical practice (0.33, 0.67, 1.33, 2.67mg/ml). Cell death was measured by flow cytometry with annexin V-FITC. The expression of Bcl-2 and Bcl-XL mRNA was determined by RT-PCR.
Results: :
Under low oxidative stress conditions (50 and 100 µM), cell apoptosis was not significantly different at all concentrations of bevacizumab. Bcl-2 mRNA expression were decreased by increasing concentrations of bevacizumab (0.33, 0.67, 1.33, 2.67mg/ml) under low oxidative stress. Under moderate oxidative stress conditions (200 µM), cell survival was increased. Cell survival and Bcl-2 mRNA expression were decreased by increasing concentrations of bevacizumab (0.33, 0.67, 1.33, 2.67mg/ml) under moderate oxidative stress. Under high oxidative stress (300 µM) conditions, cell survival increased at high concentrations of bevacizumab(1.33, 2.67mg/ml), but it did not correlate to Bcl-2 expression. No statistically significant results in the expression of Bcl-XL were observed under any condition.
Conclusions: :
Withdrawal of VEGF, as in eyes with age-related macular degeneration, leads to RPE cell apoptosis and influences the expression of anti-apoptotic genes such as Bcl-2. Anti-VEGF therapies like bevacizumab should be administered with caution until a definite conclusion can be drawn regarding its safety.
Keywords: retinal pigment epithelium • oxidation/oxidative or free radical damage • apoptosis/cell death