Activation of pro-apoptotic p38-MAPK pathway in the prostate cancer cell line M12 expressing a truncated IGF-IR

Horm Metab Res. Nov-Dec 2003;35(11-12):751-7. doi: 10.1055/s-2004-814160.


The type I insulin-like growth factor receptor (IGF-IR) plays a critical role in signaling survival and proliferation in many cell types. Activation of IGF-IR by its ligands promotes cell proliferation via mitogen-activated protein kinase (MAPK) cascade and cell survival via phosphoinositide 3-kinase (PI3K) cascade. The IGF-IR emerges as a powerful growth factor for many tumor cells. A truncated IGF-IR 486/STOP, described as a dominant negative IGF-IR mutant, was shown to induce apoptosis and inhibit tumor growth in vivo while endogenous IGF-IR was activated. To investigate the mechanism(s) of the action of 486/STOP, we have introduced 486/STOP into the prostate tumor model cell line M12 and its derivative M12lisn that expresses high levels of wild type IGF-IR. We have found that 486/STOP induces apoptosis in M12 and M12lisn cells in culture and that 486/STOP acts through activation of the pro-apoptotic p38-MAPK without interfering with wild type IGF-IR activation. In addition, our results have indicated that 486/STOP induced activation of p38-MAPK increases through activation of endogenous IGF-IR. These data suggest that activation of the IGF-IR by 486/STOP can selectively enhance the previously reported IGF-IR pro-apoptotic signaling pathways.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Apoptosis
  • Cell Division
  • Cell Line, Tumor
  • Cell Survival
  • Enzyme Activation
  • Humans
  • Male
  • Mitogen-Activated Protein Kinases / metabolism*
  • Prostatic Neoplasms / pathology*
  • Prostatic Neoplasms / physiopathology*
  • Receptor, IGF Type 1 / genetics
  • Receptor, IGF Type 1 / physiology*
  • Sequence Deletion
  • p38 Mitogen-Activated Protein Kinases


  • Receptor, IGF Type 1
  • Mitogen-Activated Protein Kinases
  • p38 Mitogen-Activated Protein Kinases