Authors : R.Yousefi , S. K. Ardestani , M. Imani , A.A. Saboury and A. Kariminia
Abstract: Calprotectin is a calcium and zinc-binding protein complex that is abundant in the cytosol of neutrophils released under inflammatory conditions. However, the exact role of this factor has not been elucidated. It is composed of 8 and 14 kDa subunits and has the capacity to induce apoptosis in various tumor cells in a zinc-reversible manner. Reactive Oxygen Species (ROS), which are the byproducts of normal cellular oxidative process, regulates the initiation of apoptotic signaling. Recently, it has been shown that calprotectin plays an important role in phagocyte NADPH oxidase activation. In addition, the pretreatment of colon cancer cells with the antioxidant N-Acetyl-L-Cysteine (NAC) prevents apoptosis inducs by calprotectin. In the present study, we further investigate the growth inhibitory effect of calprotectin via ROS induction. For the first time it is shown that human calprotectin induced ROS and apoptosis in K562 cells revealed by conversion of Dichlorodihydroflurescin Diacetate (DCFH2-DA) to DCF and the enhancement of cell surface binding to Annexin V-FITC appropriately. More over, it is demonstrated that naturally occurring antioxidant vitamin E (50-200 �M) significantly reversed the effect of calprotectin proposing the beneficial effect of vitamin E as a natural antioxidant in restriction of calprotectin cytotoxic activity during excessive production of this protein.
R.Yousefi , S. K. Ardestani , M. Imani , A.A. Saboury and A. Kariminia , 2007. ROS Induction by Human Calprotectin in K562 and the Reversal Effect of Vitamin E. Research Journal of Biological Sciences, 2: 215-220.