Annexin V inhibits the 12-O-tetradecanoylphorbol-13-acetate-induced activation of Ras/extracellular signal-regulated kinase (ERK) signaling pathway upstream of Shc in MCF-7 cells

Oncogene. 2000 Jun 8;19(25):2904-12. doi: 10.1038/sj.onc.1203615.


Annexin V is a Ca2+-dependent phospholipid binding protein. Although it has been shown to inhibit protein kinase C (PKC) in cell-free systems, its role in the intact cell is unclear. A stable MCF-7 human breast cancer cell overexpression system was established to investigate the function of annexin V. In these cells, 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced phosphorylation and kinase activity of ERK1/2 were suppressed. Morphological changes induced by TPA were reduced by annexin V overexpression as well as by the pan-PKC inhibitor, bisindolylmaleimide I, and by the mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MEK) inhibitor, PD98059. TPA-induced MEK1/2 and Raf-1 phosphorylation were reduced in these cells. The TPA-enhanced active Ras, and its association with Raf-1, were reduced. TPA treatment of MCF-7 cells caused an increased association of Shc with Grb2. However, this increased association was prevented in the annexin V-overexpressors. p21WAF/CIP1 is responsible for inhibition of cell cycle progression in MCF-7 cells. TPA induced the expression of p21WAF/CIP1 to a greater extent in MCF-7 parent and control plasmid cells than in annexin V overexpressors. PD98059 inhibited this increase, suggesting that TPA upregulation of p21WAF/CIP1 occurs via the MEK pathway, and that annexin V overexpression blunts it. This work shows that annexin V overexpression suppresses the TPA-induced Ras/ERK signaling by inhibiting at/or upstream of Shc, possibly through the inhibition of PKCs. Oncogene (2000).

MeSH terms

  • Annexin A5 / pharmacology*
  • Cyclin-Dependent Kinase Inhibitor p21
  • Cyclins / metabolism
  • Enzyme Inhibitors / pharmacology
  • Humans
  • Mitogen-Activated Protein Kinases / metabolism*
  • Phosphorylation
  • Protein Kinase C / antagonists & inhibitors
  • Signal Transduction / drug effects*
  • Tetradecanoylphorbol Acetate / antagonists & inhibitors*
  • Tetradecanoylphorbol Acetate / pharmacology
  • Tumor Cells, Cultured


  • Annexin A5
  • CDKN1A protein, human
  • Cyclin-Dependent Kinase Inhibitor p21
  • Cyclins
  • Enzyme Inhibitors
  • Protein Kinase C
  • Mitogen-Activated Protein Kinases
  • Tetradecanoylphorbol Acetate