Inhibition of transforming activity of the ret/ptc1 oncoprotein by a 2-indolinone derivative

Int J Cancer. 2000 Feb 1;85(3):384-90.


ret-derived oncogenes are frequently and specifically expressed in thyroid tumors. In contrast to the ret receptor, ret oncoproteins are characterized by ligand-independent tyrosine-kinase activity and tyrosine phosphorylation. In this study, novel synthetic arylidene 2-indolinone compounds were evaluated as inhibitors of the ret/ptc1 tyrosine kinase. Four compounds inhibited ret/ptc1 activity in immunokinase assay (IC50 27-42 microM) including one (1,3-dihydro-5,6-dimethoxy-3-[(4-hydroxyphenyl) methylene)-2H-indol-2-one) (Cpd 1) that selectively inhibited the anchorage-independent growth of NIH3T3 transformants expressing the ret/ptc1 gene (NIH3T3ptc1 cells). Following exposure to Cpd 1, the transformed phenotype of NIH3T3ptc1 cells was reverted, within 24 hr, to a normal fibroblast-like morphology in adherent-cell culture. In these cells, the constitutive tyrosine phosphorylation of ret/ptc1, of the transducing adaptor protein shc and of a series of co-immunoprecipitated peptides became much reduced, as demonstrated by immunoprecipitation/Western-blot analyses. Data presented provide additional evidence that ret/ptc1 is directly implicated in malignant transformation, and demonstrate the ability of Cpd 1 to interfere in the signal transduction pathway constitutively activated by the ret/ptc1 oncoprotein. These results confirm the interest of the arylidene 2-indolinone class of tyrosine-kinase inhibitors as tools for the study of ret signaling and the control of cell proliferation in ret- and ret/ptcs-associated diseases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blotting, Western
  • Carcinoma, Squamous Cell / enzymology
  • Carcinoma, Squamous Cell / metabolism*
  • Enzyme Inhibitors / metabolism*
  • Genes, ras*
  • Humans
  • Indoles / metabolism*
  • Kinetics
  • Mice
  • Oncogene Proteins, Fusion / metabolism*
  • Oxindoles
  • Phenotype
  • Precipitin Tests
  • Protein-Tyrosine Kinases / antagonists & inhibitors*
  • Signal Transduction
  • Thyroid Neoplasms / enzymology
  • Thyroid Neoplasms / metabolism*
  • Tumor Cells, Cultured
  • Urinary Bladder Neoplasms / enzymology
  • Urinary Bladder Neoplasms / metabolism*


  • 1,3-dihydro-5,6-dimethoxy-3-((4-hydroxyphenyl)methylene)-2H-indol-2-one
  • Enzyme Inhibitors
  • Indoles
  • Oncogene Proteins, Fusion
  • Oxindoles
  • 2-oxindole
  • Protein-Tyrosine Kinases
  • ret-PTC fusion oncoproteins, human