Delta MEKK3:ER* activation induces a p38 alpha/beta 2-dependent cell cycle arrest at the G2 checkpoint

Oncogene. 2002 Nov 21;21(53):8089-104. doi: 10.1038/sj.onc.1206000.

Abstract

Whilst many studies have examined the role of the MAP Kinases in regulating the G1-->S transition, much less is known about the function of these pathways in regulating other cell cycle transitions. Stimulation of the conditional mutant Delta MEKK3:ER* in asynchronous hamster (CCl39) and rat (Rat-1) fibroblasts resulted in the strong activation of endogenous JNK and p38 but only a weak activation of ERK. Activation of Delta MEKK3:ER* inhibited cell proliferation through a combination of an initial G1 and G2 cell cycle arrest, followed by a delayed onset of apoptosis. When cells were synchronized in S phase with aphidicolin and then released, activation of Delta MEKK3:ER* resulted in the up-regulation of p21(CIP1) and a pronounced inhibition of cyclin A/CDK2 and cyclin B1/CDK1 kinase activity. Analysis of mitotic figures indicated that cells failed to enter mitosis, arresting late in G2. Delta MEKK3:ER*-mediated CDK inhibition and G2 arrest did not absolutely require p21(CIP1), since both events were observed in Rat-1 cells in which p21(CIP1) is transcriptionally silenced due to promoter methylation. Rather, CDK inhibition was associated with a down-regulation of cyclin A and B1 expression. Finally, application of the p38 inhibitor SB203580 partially restored cyclin B associated kinase activity and allowed cells to proceed through mitosis into the next G1 phase, suggesting that activation of the p38 alpha/beta 2 pathway can promote a G2 cell cycle arrest.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Aphidicolin / pharmacology
  • Apoptosis / physiology
  • CDC2 Protein Kinase / antagonists & inhibitors
  • CDC2-CDC28 Kinases*
  • Cells, Cultured / cytology
  • Cricetinae
  • Cyclin A / antagonists & inhibitors
  • Cyclin B / antagonists & inhibitors
  • Cyclin B1
  • Cyclin-Dependent Kinase 2
  • Cyclin-Dependent Kinase Inhibitor p21
  • Cyclin-Dependent Kinases / antagonists & inhibitors
  • Cyclins / biosynthesis
  • Cyclins / deficiency
  • Cyclins / genetics
  • DNA Methylation
  • Enzyme Activation
  • Enzyme Inhibitors / pharmacology
  • Fibroblasts / cytology*
  • G1 Phase / physiology
  • G2 Phase / physiology*
  • Gene Silencing
  • Genes, Synthetic
  • Humans
  • Imidazoles / pharmacology
  • JNK Mitogen-Activated Protein Kinases
  • MAP Kinase Kinase Kinase 3
  • MAP Kinase Kinase Kinases / chemistry
  • MAP Kinase Kinase Kinases / genetics
  • MAP Kinase Kinase Kinases / physiology*
  • Mitogen-Activated Protein Kinase 11
  • Mitogen-Activated Protein Kinase 3
  • Mitogen-Activated Protein Kinases / antagonists & inhibitors
  • Mitogen-Activated Protein Kinases / metabolism
  • Mitogen-Activated Protein Kinases / physiology*
  • Protein-Serine-Threonine Kinases / antagonists & inhibitors
  • Pyridines / pharmacology
  • Rats
  • Receptors, Estrogen / drug effects
  • Receptors, Estrogen / genetics
  • Recombinant Fusion Proteins / physiology
  • Sequence Deletion
  • Tamoxifen / analogs & derivatives*
  • Tamoxifen / pharmacology
  • p38 Mitogen-Activated Protein Kinases

Substances

  • CCNB1 protein, human
  • CDKN1A protein, human
  • Ccnb1 protein, rat
  • Cdkn1a protein, rat
  • Cyclin A
  • Cyclin B
  • Cyclin B1
  • Cyclin-Dependent Kinase Inhibitor p21
  • Cyclins
  • Enzyme Inhibitors
  • Imidazoles
  • Pyridines
  • Receptors, Estrogen
  • Recombinant Fusion Proteins
  • Tamoxifen
  • afimoxifene
  • Aphidicolin
  • Protein-Serine-Threonine Kinases
  • CDC2 Protein Kinase
  • CDC2-CDC28 Kinases
  • CDK2 protein, human
  • Cdk2 protein, rat
  • Cyclin-Dependent Kinase 2
  • Cyclin-Dependent Kinases
  • JNK Mitogen-Activated Protein Kinases
  • Mitogen-Activated Protein Kinase 11
  • Mitogen-Activated Protein Kinase 3
  • Mitogen-Activated Protein Kinases
  • p38 Mitogen-Activated Protein Kinases
  • MAP Kinase Kinase Kinase 3
  • MAP Kinase Kinase Kinases
  • MAP3K3 protein, human
  • SB 203580