title: C-Myc and Bcl-2 protein expression during the induction of apoptosis and differentiation in TNF alpha-treated HL-60 cells.
abstract: We examined c-Myc and Bcl-2 protein expressions during the induction of apoptosis and differentiation in TNF alpha-treated HL-60 cells using a two-color flow cytometric method. We found that c-Myc protein was rapidly down-regulated in the apoptotic cells while Bcl-2 protein was expressed at relatively high levels. Concomitantly with terminal differentiation Bcl-2 protein was down-regulated in differentiating cells as well as c-Myc protein. We also showed that c-myc antisense oligonucleotides could induce apoptosis in HL-60 cells whereas bcl-2 antisense did not induce apoptosis during the early time of treatment. These results suggest that the down-regulation of c-Myc protein expression is a primary event to induce apoptosis and neither consistent expression of c-Myc protein nor rapid down-regulation of Bcl-2 protein is necessary for the initial processing of apoptosis in HL-60 cells. Furthermore, concomitant down-regulation of c-Myc and Bcl-2 is closely associated with terminal differentiation and apoptotic cell death of HL-60 cells treated with TNF alpha.
authors.affiliation: Third Division of Internal Medicine, Shimane Medical University, Izumo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Kumakura
authors.forename: H
authors.initials: H
authors.lastname: Ishikura
authors.forename: H
authors.initials: H
authors.lastname: Tsumura
authors.forename: Y
authors.initials: Y
authors.lastname: Iwata
authors.forename: J
authors.initials: J
authors.lastname: Endo
authors.forename: S
authors.initials: S
authors.lastname: Kobayashi
mesh_terms: D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D004273:DNA, Neoplasm / Q000378:metabolism; D015536:Down-Regulation; D005434:Flow Cytometry; D018922:HL-60 Cells / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism / Q000502:physiology*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D004273:DNA, Neoplasm; D016376:Oligonucleotides, Antisense; D019253:Proto-Oncogene Proteins c-bcl-2; D016271:Proto-Oncogene Proteins c-myc; D014409:Tumor Necrosis Factor-alpha