title: Cytokinin-induced differentiation of human myeloid leukemia HL-60 cells is associated with the formation of nucleotides, but not with incorporation into DNA or RNA.
abstract: Cytokinins are important purine derivatives that act as hormones to control many processes in plants. Cytokinins such as isopentenyladenine (IPA), kinetin and benzyladenine were very effective at inducing the granulocytic differentiation of human myeloid leukemia HL-60 cells. The metabolism of cytokinins to their nucleotides was closely associated with cytokinin-induced differentiation and growth inhibition. When the cells were incubated with [14C]-benzyladenine, radioactivity was significantly incorporated into RNA and DNA. However, the radioactive nucleotides in RNA or DNA were adenine nucleotides, not benzyladenine nucleotides, suggesting that cytokinins were not incorporated into RNA and DNA. The benzyladenine nucleotides were not stably released into the medium in intact form. Cytokinins effectively induced a phosphorylated (active) form of mitogen-activated protein kinase (MAPK). MAPK activation was necessary for cytokinin-induced differentiation, because PD98059, an inhibitor of MAPK kinase, suppressed the differentiation induced by cytokinins. These results suggest that cytokinin nucleotides themselves play an important role in inducing the differentiation of HL-60 cells.
authors.affiliation: Department of Chemotheraphy, Saitama Cancer Center Research Institute, 818 Komuro, Ina, Saitama 362-0806, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Ishii
authors.forename: Shingo
authors.initials: S
authors.lastname: Sakai
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Honma
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives* / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D003583:Cytokinins / Q000378:metabolism / Q000494:pharmacology*; D004247:DNA / Q000096:biosynthesis; D018922:HL-60 Cells; D006801:Humans; D007951:Leukemia, Myeloid / Q000473:pathology*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009711:Nucleotides / Q000096:biosynthesis*; D010766:Phosphorylation; D012313:RNA / Q000096:biosynthesis; D011849:Radioactive Tracers
chemical_list: D003583:Cytokinins; D009711:Nucleotides; D011849:Radioactive Tracers; D012313:RNA; C079839:3-benzyladenine; D004247:DNA; D020928:Mitogen-Activated Protein Kinases; D000225:Adenine