title: Tyrphostin AG 1024 modulates radiosensitivity in human breast cancer cells.
abstract: Insulin-like growth factor-1 (IGF-1) plays an important growth-promoting effect by activating the PI3K/Akt signalling pathway, inhibiting apoptotic pathways and mediating mitogenic actions. Tyrphostin AG 1024, one selective inhibitor of IGF-1R, was used to evaluate effects on proliferation, radiosensitivity, and radiation-induced cell apoptosis in a human breast cancer cell line MCF-7. Exposure to Tyrphostin AG 1024 inhibited proliferation and induced apoptosis in a time-dependent manner, and the degree of growth inhibition for IC20 plus irradiation (4 Gy) was up to 50% compared to the control. Examination of Tyrphostin AG 1024 effects on radiation response demonstrated a marked enhancement in radiosensitivity and amplification of radiation-induced apoptosis. Western blot analysis indicated that Tyrphostin AG 1024-induced apoptosis was associated with a downregulation of expression of phospho-Akt1, increased expression of Bax, p53 and p21, and a decreased expression of bcl-2 expression, especially when combined with irradiation. To our knowledge, this is the first report showing that an IGF-1 inhibitor was able to markedly increase the response of tumour cells to ionizing radiation. These results suggest that Tyrphostin AG 1024 could be used as a potential therapeutic agent in combination with irradiation.
authors.affiliation: Laboratoire UPRES EA No 27-10 Radiosensibilité-Radiocarcinogénèse Humaine and Unité METSI, Institut Gustave-Roussy, 94805 Villejuif Cédex, France.
authors.forename: B
authors.initials: B
authors.lastname: Wen
authors.forename: E
authors.initials: E
authors.lastname: Deutsch
authors.forename: E
authors.initials: E
authors.lastname: Marangoni
authors.forename: V
authors.initials: V
authors.lastname: Frascona
authors.forename: L
authors.initials: L
authors.lastname: Maggiorella
authors.forename: B
authors.initials: B
authors.lastname: Abdulkarim
authors.forename: N
authors.initials: N
authors.lastname: Chavaudra
authors.forename: J
authors.initials: J
authors.lastname: Bourhis
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology*; D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D001943:Breast Neoplasms / Q000473:pathology*; D002455:Cell Division / Q000187:drug effects; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000096:biosynthesis / Q000235:genetics; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects / Q000528:radiation effects; D019254:Genes, bcl-2; D016158:Genes, p53; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000502:physiology*; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000235:genetics; D010766:Phosphorylation / Q000187:drug effects; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis / Q000235:genetics; D051057:Proto-Oncogene Proteins c-akt; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis; D011836:Radiation Tolerance / Q000187:drug effects; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology*; D020794:Receptor Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D017526:Receptor, IGF Type 1 / Q000037:antagonists & inhibitors*; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D014410:Tumor Stem Cell Assay; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis; D020032:Tyrphostins / Q000494:pharmacology*; D051028:bcl-2-Associated X Protein
chemical_list: C494826:BAX protein, human; C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004791:Enzyme Inhibitors; D009363:Neoplasm Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D011838:Radiation-Sensitizing Agents; D016159:Tumor Suppressor Protein p53; D020032:Tyrphostins; D051028:bcl-2-Associated X Protein; C447031:tyrphostin AG 1024; D007334:Insulin-Like Growth Factor I; D020794:Receptor Protein-Tyrosine Kinases; D017526:Receptor, IGF Type 1; C494918:AKT1 protein, human; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt