title: Wortmannin inhibits IGF-dependent differentiation in the mouse myogenic cell line C2.
abstract: Evidence has accumulated that suggests that insulin-like growth factors (IGFs) exert a positive influence on myoblast differentiation. We have undertaken to study the signalling events required for differentiation resulting from type-1 IGF receptor stimulation in C2 myoblasts, where autocrine production of IGF-II was abolished by means of antisense RNA. Exposure of the cells to IGFs leads to a rapid and sustained activation of phosphatidyl-inositol 3-kinase followed by the expression of Myod, myogenin and differentiation. The fungal metabolite, wortmannin, inhibits both PI 3-kinase and muscle differentiation with an IC 50 in the nanomolar range. IGFs are also known to cause a rapid activation of MAP kinase. However, the synthetic inhibitor of MEK, PD098059, which prevents MAP kinase activation, does not affect myoblast differentiation. These results provide evidence that PI 3-kinase, but not MAP kinase, is required for insulin-like growth factor receptor-dependent differentiation of muscle cells.
authors.affiliation: Laboratoire de développement cellulaire, Ura CNRS 1947, Institut Pasteur, Paris, France.
authors.forename: C
authors.initials: C
authors.lastname: Pinset
authors.forename: A
authors.initials: A
authors.lastname: Garcia
authors.forename: S
authors.initials: S
authors.lastname: Rousse
authors.forename: C
authors.initials: C
authors.lastname: Dubois
authors.forename: D
authors.initials: D
authors.lastname: Montarras
mesh_terms: D000730:Androstadienes / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D005419:Flavonoids / Q000494:pharmacology; D051379:Mice; D009132:Muscles / Q000166:cytology* / Q000201:enzymology; D013002:Somatomedins / Q000494:pharmacology*; D000077191:Wortmannin
chemical_list: D000730:Androstadienes; D004791:Enzyme Inhibitors; D005419:Flavonoids; D013002:Somatomedins; D017871:Calcium-Calmodulin-Dependent Protein Kinases; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D000077191:Wortmannin