title: AKT activation and response to interferon-beta in human cancer cells.
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.
authors.affiliation: Department of Surgery, Division of Surgical Oncology, The University of Pennsylvania Medical Center, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Hanqin
authors.initials: H
authors.lastname: Lei
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Furlong
authors.forename: Jin Hee
authors.initials: JH
authors.lastname: Ra
authors.forename: Daniel
authors.initials: D
authors.lastname: Mullins
authors.forename: Robert
authors.initials: R
authors.lastname: Cantor
authors.forename: Douglas L
authors.initials: DL
authors.lastname: Fraker
authors.forename: Francis R
authors.initials: FR
authors.lastname: Spitz
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D019008:Drug Resistance, Neoplasm; D004789:Enzyme Activation / Q000187:drug effects*; D006801:Humans; D007370:Interferon Type I / Q000494:pharmacology*; D008156:Luciferases; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins; D014407:Tumor Cells, Cultured; D051025:bcl-Associated Death Protein / Q000378:metabolism
chemical_list: D007370:Interferon Type I; D011994:Recombinant Proteins; D051025:bcl-Associated Death Protein; D008156:Luciferases; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt