AKT activation and response to interferon-beta in human cancer cells

Cancer Biol Ther. 2005 Jul;4(7):709-15. doi: 10.4161/cbt.4.7.1767. Epub 2005 Jul 28.

Abstract

Significant growth inhibition and induction of apoptosis by IFN-beta in cancer cells including colorectal cancer cells have been observed. We and others have previously reported the Stat 1 induction of TRAIL is a crucial step in the IFN-beta induced apoptosis pathway. However, when evaluating the sensitivity of a panel of colorectal cancer cell lines, we found no clear correlation between activation of the Jak/Stat signaling pathway and response to interferon. In the present study, we have evaluated the interaction of the PI3k/Akt pathway and IFN-beta induced apoptosis in human colorectal cancer cells. The results demonstrate a correlation between Akt activity, phosphorylation of Bad and resistance to interferon-induced apoptosis in these cells. The association of activation of Akt, phosphorylation of Bad and resistance to IFN-beta-induced apoptosis was further supported by the observation that disruption of the pathway in a more resistant cell line led to sensitization, and expression of an activated Akt in a more sensitive cell line led to increased resistance. Taken together, this data indicates that the PI3/Akt kinase pathway may be an important contributor to IFN-beta sensitivity and resistance in colorectal cancer cells. This data demonstrates a potential pathway by which cells may develop resistance to IFN, and further elucidation of this process may allow us to better target IFN therapy.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Apoptosis / drug effects
  • Colorectal Neoplasms / drug therapy*
  • Colorectal Neoplasms / metabolism
  • Colorectal Neoplasms / pathology
  • Drug Resistance, Neoplasm*
  • Enzyme Activation / drug effects*
  • Humans
  • Interferon Type I / pharmacology*
  • Luciferases
  • Phosphatidylinositol 3-Kinases / metabolism
  • Phosphorylation / drug effects
  • Proto-Oncogene Proteins c-akt / genetics
  • Proto-Oncogene Proteins c-akt / metabolism*
  • Recombinant Proteins
  • Tumor Cells, Cultured
  • bcl-Associated Death Protein / metabolism

Substances

  • Interferon Type I
  • Recombinant Proteins
  • bcl-Associated Death Protein
  • Luciferases
  • Phosphatidylinositol 3-Kinases
  • Proto-Oncogene Proteins c-akt