Transcriptional and ERK1/2-dependent synergistic upregulation of p21(cip1/waf1) associated with steel factor synergy in MO7e.
Steel factor (SLF) plus GM-CSF induces proliferative synergy in myeloid progenitors and factor-dependent cell line MO7e. We previously reported that the protein level of cyclin-dependent kinase inhibitor p21(cip1/waf1) (p21) increased synergistically when MO7e cells were stimulated with SLF plus GM-CSF and that p21 induction was required for SLF synergistic responses. Here we show that this p21 induction is regulated at the transcriptional level. Based on use of a multiprobe RNase protection assay, the synergistic increase of p21 mRNA was unique among many cell cycle regulators. While STAT5A and 5B were activated after stimulation with GM-CSF alone or SLF plus GM-CSF, there was no difference in activation between the groups. p44/42 MAP kinase (ERK1/2) was synergistically activated by SLF plus GM-CSF, but SAPK/JNK and p38 MAP kinase were not. Synergistic induction of p21 was significantly decreased with a MEK1 inhibitor, suggesting that the ERK1/2 pathway is involved in the synergistic increase of p21 after GM-CSF plus SLF stimulation.
Lee
Y
Y
Department of Microbiology/Immunology, University of Indiana School of Medicine, Indianapolis, Indiana 46202, USA.
Mantel
C
C
Anzai
N
N
Braun
S E
SE
Broxmeyer
H E
HE
D002453:Cell Cycle; D002460:Cell Line; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D004357:Drug Synergism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000008:administration & dosage; D006410:Hematopoiesis / Q000187:drug effects; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D048369:MAP Kinase Kinase 1; D008894:Milk Proteins; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D050799:STAT5 Transcription Factor; D019089:Stem Cell Factor / Q000008:administration & dosage / Q000494:pharmacology*; D015534:Trans-Activators / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects; D025521:Tumor Suppressor Proteins; D015854:Up-Regulation / Q000187:drug effects
C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D005419:Flavonoids; D008894:Milk Proteins; D012333:RNA, Messenger; D050799:STAT5 Transcription Factor; C494092:STAT5A protein, human; D019089:Stem Cell Factor; D015534:Trans-Activators; D025521:Tumor Suppressor Proteins; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D017346:Protein Serine-Threonine Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048369:MAP Kinase Kinase 1; C482125:MAP2K1 protein, human; D020929:Mitogen-Activated Protein Kinase Kinases; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one