title: Autocrine insulin-like growth factor-I signaling promotes growth and survival of human acute myeloid leukemia cells via the phosphoinositide 3-kinase/Akt pathway.
abstract: Insulin-like growth factor (IGF) signaling plays an important role in various human cancers. Therefore, the role of insulin-like growth factor I (IGF-I) signaling in growth and survival of acute myeloid leukemia (AML) cells was investigated. Expression of the IGF-I receptor (IGF-IR) and its ligand IGF-I were detected in a panel of human AML blasts and cell lines. IGF-I and insulin promoted the growth of human AML blasts in vitro and activated the phosphoinositide 3-kinase (PI3K)/Akt and the extracellular signal-regulated kinase (Erk) pathways. IGF-I-stimulated growth of AML blasts was blocked by an inhibitor of the PI3K/Akt pathway. Moreover, downregulation of the class Ia PI3K isoforms p110beta and p110delta by RNA interference impaired IGF-I-stimulated Akt activation, cell growth and survival in AML cells. Proliferation of a panel of AML cell lines and blasts isolated from patients with AML was inhibited by the IGF-IR kinase inhibitor NVP-AEW541 or by an IGF-IR neutralizing antibody. In addition to its antiproliferative effects, NVP-AEW541 sensitized primary AML blasts and cell lines to etoposide-induced apoptosis. Together, our data describe a novel role for autocrine IGF-I signaling in the growth and survival of primary AML cells. IGF-IR inhibitors in combination with chemotherapeutic agents may represent a novel approach to target human AML.
authors.affiliation: Division of Clinical Chemistry and Biochemistry, University Children's Hospital Zurich, Zurich, Switzerland.
authors.forename: K T
authors.initials: KT
authors.lastname: Doepfner
authors.forename: O
authors.initials: O
authors.lastname: Spertini
authors.forename: A
authors.initials: A
authors.lastname: Arcaro
mesh_terms: D000208:Acute Disease; D000906:Antibodies / Q000494:pharmacology; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D019898:Autocrine Communication; D002455:Cell Division / Q000502:physiology; D045744:Cell Line, Tumor; D003561:Cytarabine / Q000494:pharmacology; D015536:Down-Regulation; D005047:Etoposide / Q000494:pharmacology; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D007951:Leukemia, Myeloid / Q000378:metabolism / Q000473:pathology*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D017526:Receptor, IGF Type 1 / Q000276:immunology / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D000906:Antibodies; D000964:Antimetabolites, Antineoplastic; D000972:Antineoplastic Agents, Phytogenic; D003561:Cytarabine; D007334:Insulin-Like Growth Factor I; D005047:Etoposide; D019869:Phosphatidylinositol 3-Kinases; D017526:Receptor, IGF Type 1; D051057:Proto-Oncogene Proteins c-akt