title: The PI3-kinase isoform p110δ is essential for cell transformation induced by the D816V mutant of c-Kit in a lipid-kinase-independent manner.
abstract: PI3-kinase has a crucial role in transformation mediated by the oncogenic c-Kit mutant D816V. In this study, we demonstrate that the c-Kit/D816V-mediated cell survival is dependent on an intact direct binding of PI3-kinase to c-Kit. However, mutation of this binding site had little effect on the PI3-kinase activity in the cells, suggesting that c-Kit/D816V-mediated cell survival is dependent on PI3-kinase but not its kinase activity. Furthermore, inhibition of the lipid kinase activity of PI3-kinase led only to a slight inhibition of cell survival. Knockdown of the predominant PI3-kinase isoform p110δ in c-Kit/D816V-expressing Ba/F3 cells led to reduced cell transformation both in vitro and in vivo without affecting the overall PI3-kinase activity. This suggests that p110δ has a lipid-kinase-independent role in c-Kit/D816V-mediated cell transformation. We furthermore demonstrate that p110δ is phosphorylated at residues Y524 and S1039 and that phosphorylation requires an intact binding site for PI3-kinase in c-Kit/D816V. Overexpression of p110δ carrying the Y523F and S1038A mutations significantly reduced c-Kit/D816V-mediated cell survival and proliferation. Taken together, our results demonstrate an important lipid-kinase-independent role of p110δ in c-Kit/D816V-mediated cell transformation. This furthermore suggests that p110δ could be a potential diagnostic factor and selective therapeutic target for c-Kit/D816V-expressing malignancies.
authors.affiliation: Experimental Clinical Chemistry, Department of Laboratory Medicine, Lund University, Skåne University Hospital, Malmö, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Sun
authors.affiliation: Center for Molecular Pathology, Department of Laboratory Medicine, CREATE Health, Lund University, Skåne University Hospital, Malmö, Sweden.
authors.forename: S
authors.initials: S
authors.lastname: Mohlin
authors.affiliation: Novo Nordisk Foundation Center for Protein Research, Department of Proteomics, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark.
authors.forename: A
authors.initials: A
authors.lastname: Lundby
authors.affiliation: Experimental Clinical Chemistry, Department of Laboratory Medicine, Lund University, Skåne University Hospital, Malmö, Sweden.
authors.forename: J U
authors.initials: JU
authors.lastname: Kazi
authors.affiliation: Ludwig Institute for Cancer Research, Uppsala, Sweden.
authors.forename: U
authors.initials: U
authors.lastname: Hellman
authors.affiliation: Center for Molecular Pathology, Department of Laboratory Medicine, CREATE Health, Lund University, Skåne University Hospital, Malmö, Sweden.
authors.forename: S
authors.initials: S
authors.lastname: Påhlman
authors.affiliation: Novo Nordisk Foundation Center for Protein Research, Department of Proteomics, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark.
authors.forename: J V
authors.initials: JV
authors.lastname: Olsen
authors.affiliation: Experimental Clinical Chemistry, Department of Laboratory Medicine, Lund University, Skåne University Hospital, Malmö, Sweden.
authors.forename: L
authors.identifier: 0000000207195336
authors.initials: L
authors.lastname: Rönnstrand
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001665:Binding Sites / Q000235:genetics; D015153:Blotting, Western; D019556:COS Cells; D002460:Cell Line; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002470:Cell Survival / Q000235:genetics; D002471:Cell Transformation, Neoplastic / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D002522:Chlorocebus aethiops; D002867:Chromones / Q000494:pharmacology; D058543:Class Ia Phosphatidylinositol 3-Kinase / Q000235:genetics* / Q000378:metabolism; D005260:Female; D008815:Mice, Inbred Strains; D008819:Mice, Nude; D009025:Morpholines / Q000494:pharmacology; D020125:Mutation, Missense; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics* / Q000378:metabolism; D011799:Quinazolines / Q000494:pharmacology; D034622:RNA Interference; D012694:Serine / Q000235:genetics / Q000378:metabolism; D014443:Tyrosine / Q000235:genetics / Q000378:metabolism
chemical_list: D002867:Chromones; C477872:IC 87114; D009025:Morpholines; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011799:Quinazolines; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D014443:Tyrosine; D012694:Serine; D058543:Class Ia Phosphatidylinositol 3-Kinase; D019009:Proto-Oncogene Proteins c-kit; D000225:Adenine