Bcl-2 does not protect Burkitt's lymphoma cells from oxidant-induced cell death.
Bcl-2 is an oncogene that confers deregulated growth potential to B lymphocytes through its ability to inhibit apoptotic cell death. A specific molecular activity for the Bcl-2 protein has not been identified, but several lines of evidence have supported a role in protection of cells from oxidative stress. We investigated whether there is a correlation between expression of high levels of Bcl-2 and susceptibility of human Burkitt's lymphoma cell lines to H2O2-induced killing. The amount of H2O2 required to kill 50% of cells in 24 hours varied widely in the seven different lymphoma cell lines that were tested, ranging from 35 to 500 micromol/L H2O2. However, expression of high levels of endogenous Bcl-2 did not protect the cells from H2O2-induced killing, even though it was effective in protecting the cells from apoptosis induced by agents such as A23187. Thus, Bcl-2 was functional in preventing apoptosis but did not act in an antioxidant capacity. The results were confirmed using a Burkitt's lymphoma cell line overexpressing transfected bcl-2. The results may be explained by the observation that H2O2 was inefficient at inducing apoptosis in these mature B-cell lines. Nonapoptotic death induced by H2O2 was not prevented by Bcl-2.
Lee
Y
Y
Laboratory of Immunology, Food and Drug Administration, Center for Biologics Evaluation and Research, Bethesda, MD 20892-4555, USA.
Shacter
E
E
D017209:Apoptosis / Q000187:drug effects; D002051:Burkitt Lymphoma / Q000473:pathology*; D000001:Calcimycin / Q000494:pharmacology; D016923:Cell Death / Q000187:drug effects; D016158:Genes, p53; D006566:Herpesviridae Infections / Q000473:pathology; D004854:Herpesvirus 4, Human; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D009363:Neoplasm Proteins / Q000502:physiology*; D018384:Oxidative Stress; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014162:Transfection; D014407:Tumor Cells, Cultured / Q000187:drug effects; D014412:Tumor Virus Infections / Q000473:pathology
D009363:Neoplasm Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D011993:Recombinant Fusion Proteins; D000001:Calcimycin; D006861:Hydrogen Peroxide