Gefitinib-sensitizing EGFR mutations in lung cancer activate anti-apoptotic pathways.
Gefitinib (Iressa, Astra Zeneca Pharmaceuticals) is a tyrosine kinase inhibitor that targets the epidermal growth factor receptor (EGFR) and induces dramatic clinical responses in nonsmall cell lung cancers (NSCLCs) with activating mutations within the EGFR kinase domain. We report that these mutant EGFRs selectively activate Akt and signal transduction and activator of transcription (STAT) signaling pathways, which promote cell survival, but have no effect on extracellular signal-regulated kinase signaling, which induces proliferation. NSCLC cells expressing mutant EGFRs underwent extensive apoptosis after small interfering RNA-mediated knockdown of the mutant EGFR or treatment with pharmacological inhibitors of Akt and STAT signaling and were relatively resistant to apoptosis induced by conventional chemotherapeutic drugs. Thus, mutant EGFRs selectively transduce survival signals on which NSCLCs become dependent; inhibition of those signals by gefitinib may contribute to the drug's efficacy.
Center for Molecular Therapeutics, Massachusetts General Hospital Cancer Center and Harvard Medical School, Building 149, 13th Street, Charlestown, MA 02129, USA.
Raffaella
R
Sordella
Daphne W
DW
Bell
Daniel A
DA
Haber
Jeffrey
J
Settleman
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology; D020134:Catalytic Domain; D002460:Cell Line; D045744:Cell Line, Tumor; D002470:Cell Survival; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D004789:Enzyme Activation; D066246:ErbB Receptors / Q000235:genetics* / Q000378:metabolism*; D000077156:Gefitinib; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology; D051379:Mice; D008894:Milk Proteins; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009154:Mutation; D020125:Mutation, Missense; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D011799:Quinazolines / Q000494:pharmacology*; D034741:RNA, Small Interfering; D050799:STAT5 Transcription Factor; D017384:Sequence Deletion; D015398:Signal Transduction; D015534:Trans-Activators / Q000037:antagonists & inhibitors / Q000378:metabolism; D014162:Transfection; D014443:Tyrosine / Q000378:metabolism
D000970:Antineoplastic Agents; D004268:DNA-Binding Proteins; D008894:Milk Proteins; D011518:Proto-Oncogene Proteins; D011799:Quinazolines; D034741:RNA, Small Interfering; D050799:STAT5 Transcription Factor; D015534:Trans-Activators; D014443:Tyrosine; D066246:ErbB Receptors; C494918:AKT1 protein, human; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D020928:Mitogen-Activated Protein Kinases; D000077156:Gefitinib