Modified arabinoxylan rice bran (MGN-3/Biobran) sensitizes human T cell leukemia cells to death receptor (CD95)-induced apoptosis.
MGN-3, an arabinoxylan extracted from rice bran that is treated enzymatically with an extract from Shiitaki mushrooms, is an effective biological response modifier that increases NK cell activity, and potentiates the activity of conventional chemotherapeutic agents. In this study, we investigated the effect of MGN-3 on death receptor-induced apoptosis in the human leukemic HUT 78 cell line. HUT 78 cells were pre-treated with MGN-3, and then were incubated with the agonistic antibody against death receptor (Fas, CD95). Apoptosis was determined by the propidium iodide technique using FACScan. Activation of caspase 3, caspase 8, and caspase 9 was determined by flow cytometry. Mitochondrial membrane potential was measured with DIOC(6) dye using FACScan. Expression of CD95 and Bcl-2 were measured by flow cytometry. In a dose-dependent manner, MGN-3 enhanced anti-CD95 antibody-induced apoptosis. Increased cell death was correlated with increased depolarization of mitochondrial membrane potential and increased activation of caspase 3, caspase 8, and caspase 9. MGN-3 treatment had no effect on the level of expression of CD95, but it caused down regulation of Bcl-2 expression. These results suggest that MGN-3 increases the susceptibility of cancer cells to undergo apoptosis mediated by death ligands, which may be relevant for anti-cancer activities.
Department of Otolaryngology, Drew University of Medicine and Science, 1621 E. 120th Street, Los Angeles, CA 90059, USA. mghoneum@ucla.edu
Mamdooh
M
Ghoneum
Sastry
S
Gollapudi
D017209:Apoptosis / Q000187:drug effects*; D020169:Caspases / Q000187:drug effects / Q000378:metabolism; D045744:Cell Line, Tumor; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D004789:Enzyme Activation / Q000187:drug effects; D005434:Flow Cytometry; D006801:Humans; D015458:Leukemia, T-Cell / Q000473:pathology*; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D008928:Mitochondria / Q000187:drug effects / Q000502:physiology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis / Q000187:drug effects; D014990:Xylans / Q000494:pharmacology*; D019014:fas Receptor / Q000378:metabolism*
D019253:Proto-Oncogene Proteins c-bcl-2; D014990:Xylans; D019014:fas Receptor; C419427:polysaccharide MGN3; D020169:Caspases