BimEL-dependent apoptosis induced in peripheral blood lymphocytes with n-butyric acid is moderated by variation in expression of c-myc and p21(WAF1).
We have examined the effect of sodium butyrate (SB) on the viability of normal peripheral blood lymphocytes (PBLs) in vitro and the effect of this agent on the expression of 20 apoptosis-related genes. Data suggest that PBL treated with 2 mmol L(-1) SB resisted for at least 8 h the destructive activity of the agent, but eventually 30% of cells died within 72 h. As documented by flow cytometry and cytochrome c release study, cells underwent mitochondrial-derived apoptosis. While the expression of the majority of genes examined by RT-PCR and Western blots remained indifferent to 2 mmol L(-1) SB, the cellular levels of BimEL, c-myc, p53, and p21(WAF1) varied profoundly with the time of SB treatment. The Bax activator BimEL increased rapidly, driving cells toward apoptosis likely controlled by c-myc and p21(WAF1) activities. The c-myc, exercising the role of mediator of the function of BimEL and inhibitor of p21(WAF1) expression, decreased significantly for several hours after adding SB but within 48 h it returned to close to its original value. An apoptosis inhibitor and executive caspase substrate p21(WAF1) increased early at the beginning of treatment but subsequently, within a time frame of 72 h, profoundly dropped in terms of both a caspase-dependent and caspase-independent way. We suggest that variations in c-myc and p21(WAF1) expression delay apoptosis making PBL resistant to SB for several hours, and together with fast catabolism of SB in vivo protect PBL against the destructive activity of this anti-cancerous metabolite of colonic bacteria.
Kalousek
Ivan
I
Department of Cellular Biochemistry, Institute of Hematology and Blood Transfusion, Prague, Czech Republic. kal@uhkt.cz
Brodska
Barbora
B
Otevrelova
Petra
P
Röselova
Pavla
P
D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins / Q000235:genetics / Q000378:metabolism*; D000072224:Bcl-2-Like Protein 11; D020148:Butyric Acid / Q000494:pharmacology*; D020169:Caspases / Q000378:metabolism; D002478:Cells, Cultured; D024161:Collagen Type XI / Q000378:metabolism; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics / Q000378:metabolism*; D045304:Cytochromes c / Q000378:metabolism; D004789:Enzyme Activation; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007425:Intracellular Membranes / Q000187:drug effects; D008214:Lymphocytes / Q000187:drug effects* / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008928:Mitochondria / Q000187:drug effects; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism
D051017:Apoptosis Regulatory Proteins; C000606775:BCL2L11 protein, human; D000072224:Bcl-2-Like Protein 11; C000606776:Bcl2l11 protein, mouse; C493956:CDKN1A protein, human; C499319:COL11A2 protein, human; D024161:Collagen Type XI; D050759:Cyclin-Dependent Kinase Inhibitor p21; C489427:MYC protein, human; D008565:Membrane Proteins; C406964:Perp protein, mouse; D011518:Proto-Oncogene Proteins; D016271:Proto-Oncogene Proteins c-myc; D017382:Reactive Oxygen Species; D020148:Butyric Acid; D045304:Cytochromes c; D020169:Caspases