caa a22 4500 606175709 CHVBK 20210128100744.0 cr unu---uuuuu 210128e20151101xx s 000 0 eng 10.1007/s00018-015-1944-9 doi (NATIONALLICENCE)springer-10.1007/s00018-015-1944-9 PI3 kinase is indispensable for oncogenic transformation by the V560D mutant of c-Kit in a kinase-independent manner [Elektronische Daten] [Oscar Lindblad, Julhash Kazi, Lars Rönnstrand, Jianmin Sun] Oncogenic mutants of c-Kit are often found in mastocytosis, gastrointestinal stromal tumors and acute myeloid leukemia. The activation mechanism of the most commonly occurring mutation, D816V in exon 17 of c-Kit, has been well-studied while other mutations remain fairly uncharacterized in this respect. In this study, we show that the constitutive activity of the exon 11 mutant V560D is weaker than the D816V mutant. Phosphorylation of downstream signaling proteins induced by the ligand for c-Kit, stem cell factor, was stronger in c-Kit/V560D expressing cells than in cells expressing c-kit/D816V. Although cells expressing c-Kit/V560D showed increased ligand-independent proliferation and survival compared to wild-type c-Kit-expressing cells, these biological effects were weaker than in c-Kit/D816V-expressing cells. In contrast to cells expressing wild-type c-Kit, cells expressing c-Kit/V560D were independent of Src family kinases for downstream signaling. However, the independence of Src family kinases was not due to a Src-like kinase activity that c-Kit/D816V displayed. Point mutations that selectively block the association of PI3 kinase with c-Kit/V560D inhibited ligand-independent activation of the receptor, while inhibition of the kinase activity of PI3 kinase with pharmacological inhibitors did not affect the kinase activity of the receptor. This suggests a lipid kinase-independent key role of PI3 kinase in c-Kit/V560D-mediated oncogenic signal transduction. Thus, PI3 kinase is an attractive therapeutic target in malignancies induced by c-Kit mutations independent of its lipid kinase activity. Springer Basel, 2015 Receptor tyrosine kinase nationallicence Ba/F3 nationallicence Cancer nationallicence LY294002 nationallicence GDC0941 nationallicence Signaling nationallicence Lindblad Oscar Division of Translational Cancer Research and Lund Stem Cell Center, Department of Laboratory Medicine, Lund University, Medicon Village 404C3, Scheelevägen 8, 22363, Lund, Sweden aut Kazi Julhash Division of Translational Cancer Research and Lund Stem Cell Center, Department of Laboratory Medicine, Lund University, Medicon Village 404C3, Scheelevägen 8, 22363, Lund, Sweden aut Rönnstrand Lars Division of Translational Cancer Research and Lund Stem Cell Center, Department of Laboratory Medicine, Lund University, Medicon Village 404C3, Scheelevägen 8, 22363, Lund, Sweden aut Sun Jianmin Division of Translational Cancer Research and Lund Stem Cell Center, Department of Laboratory Medicine, Lund University, Medicon Village 404C3, Scheelevägen 8, 22363, Lund, Sweden aut Cellular and Molecular Life Sciences Springer Basel 72/22(2015-11-01), 4399-4407 1420-682X 72:22<4399 2015 72 18 https://doi.org/10.1007/s00018-015-1944-9 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00018-015-1944-9 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Lindblad Oscar Division of Translational Cancer Research and Lund Stem Cell Center, Department of Laboratory Medicine, Lund University, Medicon Village 404C3, Scheelevägen 8, 22363, Lund, Sweden aut NATIONALLICENCE 700 1- Kazi Julhash Division of Translational Cancer Research and Lund Stem Cell Center, Department of Laboratory Medicine, Lund University, Medicon Village 404C3, Scheelevägen 8, 22363, Lund, Sweden aut NATIONALLICENCE 700 1- Rönnstrand Lars Division of Translational Cancer Research and Lund Stem Cell Center, Department of Laboratory Medicine, Lund University, Medicon Village 404C3, Scheelevägen 8, 22363, Lund, Sweden aut NATIONALLICENCE 700 1- Sun Jianmin Division of Translational Cancer Research and Lund Stem Cell Center, Department of Laboratory Medicine, Lund University, Medicon Village 404C3, Scheelevägen 8, 22363, Lund, Sweden aut NATIONALLICENCE 773 0- Cellular and Molecular Life Sciences Springer Basel 72/22(2015-11-01), 4399-4407 1420-682X 72:22<4399 2015 72 18