title: Protein kinase B modulates the sensitivity of human neuroblastoma cells to insulin-like growth factor receptor inhibition.
abstract: The potential of the novel insulin-like growth factor receptor (IGF-IR) inhibitor NVP-AEW541 as an antiproliferative agent in human neuroblastoma was investigated. Proliferation of a panel of neuroblastoma cell lines was inhibited by NVP-AEW541 with IC(50) values ranging from 0.15 to 5 microM. Experiments using an IGF-IR neutralizing antibody confirmed that the IGF-IR was essential to support growth of neuroblastoma cell lines. The expression levels of the IGF-IR in individual neuroblastoma cell lines did not correlate with the sensitivities to NVP-AEW541, while coexpression of the IGF-IR and the insulin receptor (IR) correlated with lower sensitivity to the inhibitor in some cell lines. Intriguingly, high levels of activation of Akt/protein kinase B (PKB) and phosphorylation of the ribosomal S6 protein were observed in neuroblastoma cell lines with decreased sensitivities to NVP-AEW541. Inhibition of Akt/PKB activity restored the sensitivity of neuroblastoma cells to the IGF-IR inhibitor. Transfection of neuroblastoma cells with activated Akt or ribosomal protein S6 kinase (S6K) decreased the sensitivity of the cells to NVP-AEW541. IGF-I-stimulated proliferation of neuroblastoma cell lines was completely blocked by NVP-AEW541, or by a combination of an inhibitor of phosphoinositide 3-kinase and rapamycin. In addition to its antiproliferative effects, NVP-AEW541 sensitized neuroblastoma cells to cisplatin-induced apoptosis. Together, our data demonstrate that NVP-AEW541 in combination with Akt/PKB inhibitors or chemotherapeutic agents may represent a novel approach to target human neuroblastoma cell proliferation.
authors.affiliation: Division of Clinical Chemistry and Biochemistry, University Children's Hospital Zurich, CH-8032 Zurich, Switzerland.
authors.forename: Ana S
authors.initials: AS
authors.lastname: Guerreiro
authors.forename: Danielle
authors.initials: D
authors.lastname: Boller
authors.forename: Tarek
authors.initials: T
authors.lastname: Shalaby
authors.forename: Michael A
authors.initials: MA
authors.lastname: Grotzer
authors.forename: Alexandre
authors.initials: A
authors.lastname: Arcaro
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000494:pharmacology; D006801:Humans; D009447:Neuroblastoma / Q000378:metabolism / Q000473:pathology*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D017526:Receptor, IGF Type 1 / Q000037:antagonists & inhibitors*; D015398:Signal Transduction
chemical_list: D000970:Antineoplastic Agents; D017526:Receptor, IGF Type 1; D051057:Proto-Oncogene Proteins c-akt; D002945:Cisplatin