title: Early decline in c-myb oncogene expression in the differentiation of human myeloblastic leukemia (ML-1) cells induced with 12-O-tetradecanoylphorbol-13-acetate.
abstract: The relationship of oncogene expression to proliferation and differentiation has been examined in a line of human myeloblastic leukemia (ML-1) cells. Proliferating leukemic cells were found to express a 4.3-kilobase cellular homologue (c-myb) of the transforming sequence of avian myeloblastosis virus. A rapid decline in the expression of this transcript was seen in cells induced to differentiate with 12-O-tetradecanoylphorbol-13-acetate. The level of c-myb RNA was decreased by greater than 50% as early as 3 hr after 12-O-tetradecanoylphorbol-13-acetate exposure, and at 8 to 72 hr the reduction was greater than or equal to 4-fold. Subsequent to the decrease in oncogene expression at 3 hr, DNA synthesis began to decline; by 24 hr, cell proliferation had ceased. At this time, monocyte- and macrophage-like cells were beginning to emerge. These findings demonstrate that c-myb is expressed during ML-1 cell proliferation and declines prior to the loss of DNA synthesis that accompanies the differentiation process.
mesh_terms: D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D004261:DNA Replication; D004587:Electrophoresis, Agar Gel; D005786:Gene Expression Regulation; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000235:genetics* / Q000473:pathology; D009693:Nucleic Acid Hybridization; D009857:Oncogenes; D010704:Phorbols / Q000494:pharmacology*; D012313:RNA / Q000032:analysis; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D010704:Phorbols; D012313:RNA; D013755:Tetradecanoylphorbol Acetate