Antioxidant enzymes in lymphocytes from normal subjects and patients with chronic lymphocytic leukaemia: increased glutathione peroxidase activity in CLL B lymphocytes

Abstract

The activities of several enzymes that protect against oxidative injury were determined in blood lymphocytes from patients with B chronic lymphocytic leukaemia (CLL) and from normal subjects. Similar glutathione reductase (GR), catalase and glucose-6-phosphate dehydrogenase (G6PD) activities were found in normal and CLL lymphocytes. Higher glutathione peroxidase (GP) activity was found in CLL lymphocytes. This activity in CLL B lymphocytes was 2-fold higher than that of normal B lymphocytes, and 3-fold higher than that of T lymphocytes from either source. Several disease processes have been associated with decreased glutathione peroxidase activity. Our finding with CLL B lymphocytes is believed to be the first example of an increased GP activity in a disease. It may reflect either the expansion of a rare type of B cell population or be an expression of the malignant process.

Effective elimination of fludarabine-resistant CLL cells by PEITC through a redox-mediated mechanism

“…Further analyses revealed that the elevated ROS in CLL cells was associated with attenuation of antioxidant capacity, since there was a significant decrease in cellular glutathione (both GSH and GSSG), whereas glutathione peroxidase (GPX) enzyme activity in CLL cells was comparable with that of normal lymphocytes ( Figure 3C,D). Because GSH can be oxidized to GSSG for exportation outside the cells and glutathione reductase activity is similar in CLL and normal lymphocytes, 25 the GSSG/GSH ratios were similar in both cell types ( Figure 3C). Western blot analysis showed an elevation of gamma-glutamyl-cysteine synthetase (GSH1) protein expression in CLL cells ( Figure 3E), suggesting a possible compensatory mechanism of CLL cells in response to ROS stress and increased consumption of glutathione.…”

Bone biopsy derived marrow stromal elements rescue chronic lymphocytic leukemia B-cells from spontaneous and drug induced cell death and facilitates an “angiogenic switch”

“…Due to prior work demonstrating the vulnerability of CLL B-cells to oxidation [25,[28][29][30], we next evaluated if MSE could rescue CLL B-cells from pharmacologic agents that induce cell death by generating oxidative stress. Glucose oxidase was used as an oxidative challenge in these experiments due to it is ability to generate a pure source of peroxides and induce cell death in CLL B-cells [27,28].…”

Investigation of Serum Enzyme Activity of Nitric Oxide (NO), Arylesterase (ARE) and Paraoxanase (PON) in Renal Tumors

“…Ozturk et al (29) observed a significant increase in xanthine oxidase (XO) activity in patients with cancerous human colorectal tissues compared to control group. The increased GSH-Px activities and GSH levels are reported in patients with leukemia (30,31). In our study group, serum ARE was significantly lower than the control group (p <0.001).…”