We explored the relationship between the cytogenetic/biologic characteristics of B-chronic lymphocytic leukemia (B-CLL) cells and their tendency to undergo spontaneous or fludarabine-induced apoptosis in vitro. B cells from 36 B-CLL patients were incubated with or without fludarabine for 48 h. Apoptosis was determined by two assays: annexin V staining and DNA staining. Fluorescence in situ hybridization was used for detection of trisomy 12, 11q deletion, and 17p deletion. Bcl-2 and CD38 expressions were determined by flow cytometry. Five patients had 17p deletion, 6 had trisomy 12, and another 6 had 11q deletion. B-CLL cells with 17p deletion had significant resistance to apoptosis induced by fludarabine and a slight spontaneous resistance to apoptosis. Bcl-2 and CD38 were not associated with in vitro spontaneous and fludarabine-induced apoptosis. In conclusion, 17p deletion, which causes loss of p53 gene, is associated with resistance to fludarabine-induced apoptosis in vitro. New treatment modalities should be tried in B-CLL patients with 17p deletion.

No abstract

Paraoxonase-1 (PON1) and PON3 (PON3) are anti-atherosclerotic enzymes, synthesized primarily in liver and bound to HDL in circulation. The aim of the present study was to investigate the effects of therapeutic doses of lipoic acid on PON1 and PON3 protein levels, mRNA expression and arylesterase activity in liver. We treated HepG2 cells with 10, 40 and 200 μM lipoic acid for 72 h. Cell viability was evaluated by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay. PON1 and PON3 protein levels were measured by Western blotting, their mRNA expression was measured by quantitative PCR and arylesterase activity was measured spectrophotometrically. 200 µM lipoic acid caused a significant increase on PON1 and PON3 protein levels and arylesterase activity as compared with control, 10 µM and 40 µM lipoic acid-treated cells. 200 µM lipoic acid also caused a significant decrease on PON1 mRNA expression whereas on a significant increase PON3 mRNA expression as compared with control, 10 µM and 40 µM lipoic acid-treated cells. Our study showed that although lipoic acid up-regulates PON3 but down-regulates PON1 mRNA expression, it increases both PON1 and PON3 protein levels and arylesterase activity in HepG2 cells. We can report that lipoic acid may be useful for preventing atherosclerosis at therapeutic doses.

Background:Apolipoprotein A-1, paraoxonase-1 and paraoxonase-3 are antioxidant and anti-atherosclerotic structural high-density lipoprotein proteins that are mainly synthesized by the liver. No study has ever been performed to specifically examine the effects of caffeine on paraoxonase enzymes and on liver apolipoprotein A-1 protein levels.Aims:To investigate the dose-dependent effects of caffeine on liver apolipoprotein A-1, paraoxonase-1 and paraoxonase-3 protein levels.Study Design:In vitro experimental study.Methods:HepG2 cells were incubated with 0 (control), 10, 50 and 200 μM of caffeine for 24 hours. Cell viability was evaluated by 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay. Apolipoprotein A-1, paraoxonase-1 and paraoxonase-3 protein levels were measured by western blotting.Results:We observed a significant increase on apolipoprotein A-1 and paraoxonase-1 protein levels in the cells incubated with 50 µM of caffeine and a significant increase on paraoxonase-1 protein level in the cells incubated with 200 µM of caffeine.Conclusion:Our study showed that caffeine does not change paraoxonase-3 protein level, but the higher doses used in our study do cause an increase in both apolipoprotein A-1 and paraoxonase-1 protein levels in liver cells.

No abstract