|Sumner, Laura - UNIV OF NORTH DAKOTA|
Submitted to: Journal of Federation of American Societies for Experimental Biology
Publication Type: Abstract Only
Publication Acceptance Date: December 10, 2000
Publication Date: March 7, 2001
Citation: Sumner, L.J. 2001. Copper deficiency in HL-60 cells increases their susceptibility to apoptosis when treated with antioxidants [abstract]. The Federation of American Societies for Experimental Biology Journal. 15:A271. Technical Abstract: Copper deficiency increases oxidative stress in mitochondria as a consequence of suppressed cytochrome-c oxidase activity. To elucidate if the treatment of copper-deficient cells with antioxidants would decrease the associated oxidative stress, we treated copper- adequate and copper- deficient HL-60 cells with separate treatments of vitamins C (0.5mM), E (0.1mM) and resveratrol (25uM). Treatment of copper-deficient cells with vitamins C and E was accompanied by marked growth inhibition and decreased viability, whereas the copper- adequate cells displayed no adverse effects. Resveratrol was not well tolerated in either group. Cytospin analysis indicated no signs of cell differentiation. To determine if the growth inhibitory and antiproliferative effects of the antioxidant treatments were associated with programmed cell death rather than necrosis, we examined several characteristic apoptotic events. Our initial studies show copper-deficient cells exposed to these antioxidants exhibit distinct morphological features of programmed cell death, such as cellular shrinkage, membrane surface blebbing and appearance of apoptotic bodies. Copper-adequate and copper-deficient cells were stained and analyzed by using cytofluorometric techniques to measure different biochemical characteristics of apoptotic cells. Copper-deficient cells treated with antioxidants when compared to copper-deficient cells without added anti- oxidants and the copper-adequate groups showed: increased plasma membrane phosphatidyl serine externalization, increased nuclear DNA fragmentation, decreased DNA content & synthesis, & decreased mitochondrial transmembrane potential. Results suggest copper-deficient HL-60 cells are more susceptible to apoptosis when treated with certain antioxidants.