Activated Ki-Ras suppresses 12-O-tetradecanoylphorbol-13-acetate-induced activation of the c-Jun NH2-terminal kinase pathway in human colon cancer cells

Cancer Res. 1999 May 15;59(10):2445-50.

Abstract

Although the frequency of activated Ki-ras genes is high in human colorectal tumors, much less is known of activated Ki-ras-mediated signaling pathways. Using gene targeting, we examined HCT116 cells that contain the Gly-13-->Asp mutation of Ki-ras and activated Ki-ras-disrupted clones derived from HCT116. 12-O-Tetradecanoylphorbol-13-acetate (TPA) induced immediate early genes, such as c-Jun, c-Fos, and Egr-1 in activated Ki-ras-disrupted clones, whereas c-Jun induction was rare in HCT116. TPA induced both phosphorylation of stress-activated protein kinase kinase 1 (SEK1) and c-Jun NH2-terminal kinase (JNK) in the activated Ki-ras-disrupted clones but not in HCT116. On the other hand, TPA-induced mitogen-activated protein kinase kinase 1/2 (MEK1/2)-extracellular signal-regulated kinase (ERK) activation was equally induced between HCT116 and the Ki-ras-disrupted clones. Furthermore, TPA-induced SEK1-JNK activation was observed in a DLD-1-derived activated Ki-ras-disrupted clone but not in DLD-1. The TPA-induced SEK1-JNK activation in these disrupted clones was completely inhibited by the protein kinase C (PKC) inhibitor, GF109203X (1 microM), but not by another PKC inhibitor, H7 (50 microM), whereas TPA-induced MEK1/2-ERK activation was partially and completely inhibited by GF109203X (1 microM) and H7 (50 microM), respectively. A phosphoinositol 3-kinase inhibitor, LY294002, did not inhibit the TPA-induced SEK1-JNK activation. Taken together, these results suggest that activated Ki-Ras-mediated signals are involved in the SEK1-JNK pathway through a PKC isotype that is distinct from that involved in MEK1/2-ERK activation in human colon cancer cells and independent of phosphoinositol 3-kinase activation, and the imbalance between ERK and JNK activity caused by activated Ki-Ras may play critical roles in human colorectal tumorigenesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles
  • Amino Acid Substitution
  • Calcium-Calmodulin-Dependent Protein Kinases / metabolism*
  • Chromones / pharmacology
  • Colonic Neoplasms / genetics
  • Colonic Neoplasms / metabolism
  • Colonic Neoplasms / pathology*
  • Culture Media, Serum-Free / pharmacology
  • Depression, Chemical
  • Enzyme Activation / drug effects
  • Enzyme Inhibitors / pharmacology
  • Gene Expression Regulation, Neoplastic*
  • Genes, Immediate-Early
  • Genes, ras*
  • Humans
  • Indoles / pharmacology
  • Isoenzymes / antagonists & inhibitors
  • Isoenzymes / physiology
  • JNK Mitogen-Activated Protein Kinases
  • MAP Kinase Kinase 1
  • MAP Kinase Kinase 2
  • MAP Kinase Kinase 4*
  • MAP Kinase Kinase Kinase 1*
  • Maleimides / pharmacology
  • Mitogen-Activated Protein Kinase 3
  • Mitogen-Activated Protein Kinase Kinases*
  • Mitogen-Activated Protein Kinases*
  • Morpholines / pharmacology
  • Mutation, Missense
  • Neoplasm Proteins / metabolism*
  • Phosphatidylinositol 3-Kinases / physiology
  • Phosphoinositide-3 Kinase Inhibitors
  • Phosphorylation
  • Protein Isoforms / physiology
  • Protein Kinase C / antagonists & inhibitors
  • Protein Kinase C / physiology
  • Protein Kinases / metabolism*
  • Protein Processing, Post-Translational
  • Protein Serine-Threonine Kinases / metabolism
  • Protein-Tyrosine Kinases / metabolism
  • Proto-Oncogene Proteins p21(ras) / genetics
  • Proto-Oncogene Proteins p21(ras) / physiology*
  • Signal Transduction / drug effects*
  • Tetradecanoylphorbol Acetate / pharmacology*
  • Tumor Cells, Cultured

Substances

  • Chromones
  • Culture Media, Serum-Free
  • Enzyme Inhibitors
  • Indoles
  • Isoenzymes
  • Maleimides
  • Morpholines
  • Neoplasm Proteins
  • Phosphoinositide-3 Kinase Inhibitors
  • Protein Isoforms
  • 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
  • Protein Kinases
  • MAP2K2 protein, human
  • Protein-Tyrosine Kinases
  • Protein Serine-Threonine Kinases
  • Protein Kinase C
  • Calcium-Calmodulin-Dependent Protein Kinases
  • JNK Mitogen-Activated Protein Kinases
  • Mitogen-Activated Protein Kinase 3
  • Mitogen-Activated Protein Kinases
  • MAP Kinase Kinase Kinase 1
  • MAP3K1 protein, human
  • MAP Kinase Kinase 1
  • MAP Kinase Kinase 2
  • MAP Kinase Kinase 4
  • MAP2K1 protein, human
  • MAP2K4 protein, human
  • Mitogen-Activated Protein Kinase Kinases
  • HRAS protein, human
  • Proto-Oncogene Proteins p21(ras)
  • bisindolylmaleimide I
  • Tetradecanoylphorbol Acetate