title: Complex regulation of CDKs and G1 arrest during the granulocytic differentiation of human myeloblastic leukemia ML-1 cells.
abstract: We previously reported that all-trans retinoic acid (ATRA) and granulocyte-macrophage colony-stimulating factor (GM-CSF) synergistically induced granulocytic differentiation in human myeloblastic leukemia ML-1 cells. The combination of these agents also suppressed DNA-synthesis. In the present study, we investigated the suppression of cyclin dependent kinase (CDK) activities resulting in G1 arrest in differentiated ML-1 cells. We show that treatment of ML-1 cells with ATRA plus GMCSF results in G1 arrest and suppression of CDK activities. Protein levels of the G1 CDKs were essentially unchanged during this time. However, we observed an increase in CDK2-bound p27 and CDK4-bound p18, and a decrease in CDK6-bound cyclin D3. These results suggest that complex regulation of CDKs play a key role in G1 arrest of ML-1 after treatment with ATRA and GM-CSF. We also showed that an increase in CDK2-bound p27 and CDK4-bound p18 are caused by treatment with ATRA and a decrease in CDK6-bound cyclin D3 is induced synergistically by treatment with both reagents. Furthermore, we propose that the changes in binding of p18 and cyclin D3 to CDKs are due to changes at the protein expression level and that the increase in p27 binding to CDK2 is due to a novel mechanism.
authors.affiliation: Department of Hygiene-chemistry, Faculty of Pharmaceutical Sciences, Science University of Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Shimizu
authors.forename: N
authors.initials: N
authors.lastname: Awai
authors.forename: K
authors.initials: K
authors.lastname: Takeda
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D042846:CDC2-CDC28 Kinases; D002352:Carrier Proteins / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D018797:Cell Cycle Proteins; D002454:Cell Differentiation / Q000187:drug effects; D051357:Cyclin-Dependent Kinase 2; D051358:Cyclin-Dependent Kinase 4; D051361:Cyclin-Dependent Kinase 6; D050763:Cyclin-Dependent Kinase Inhibitor p18; D018844:Cyclin-Dependent Kinases / Q000378:metabolism*; D004791:Enzyme Inhibitors; D016193:G1 Phase / Q000187:drug effects / Q000502:physiology; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000235:genetics / Q000473:pathology*; D008840:Microfilament Proteins / Q000378:metabolism; D009124:Muscle Proteins; D009363:Neoplasm Proteins / Q000378:metabolism*; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins; D014212:Tretinoin / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism; D025521:Tumor Suppressor Proteins
chemical_list: D000970:Antineoplastic Agents; C493971:CDKN2C protein, human; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D050763:Cyclin-Dependent Kinase Inhibitor p18; D004791:Enzyme Inhibitors; D008840:Microfilament Proteins; D009124:Muscle Proteins; D009363:Neoplasm Proteins; D011518:Proto-Oncogene Proteins; C058992:Tagln protein, mouse; D025521:Tumor Suppressor Proteins; D014212:Tretinoin; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases; C495894:CDK2 protein, human; C495900:CDK4 protein, human; C495911:CDK6 protein, human; D051357:Cyclin-Dependent Kinase 2; D051358:Cyclin-Dependent Kinase 4; D051361:Cyclin-Dependent Kinase 6; D018844:Cyclin-Dependent Kinases