Siekmann, I.-K.* ; Dierck, K.* ; Prall, S.* ; Klokow, M.* ; Strauss, J.* ; Buhs, S.* ; Wrzeszcz, A.* ; Bockmayr, M.* ; Beck, F.* ; Trochimiuk, M.* ; Gottschling, K.* ; Martens, V.* ; Khosh-Naucke, M.* ; Gerull, H.* ; Müller, J.* ; Behrmann, L.* ; Blohm, M.* ; Zahedi, R.P.* ; Jeremias, I. ; Sickmann, A.* ; Nollau, P.* ; Horstmann, M.A.*
Combined inhibition of receptor tyrosine and p21-activated kinases as a therapeutic strategy in childhood ALL.
Blood Adv. 2, 2554-2567 (2018)
Receptor tyrosine kinase (RTK)-dependent signaling has been implicated in the pathogenesis of acute lymphoblastic leukemia (ALL) of childhood. However, the RTK-dependent signaling state and its interpretation with regard to biological behavior are often elusive. To decipher signaling circuits that link RTK activity with biological output in vivo, we established patient-derived xenograft ALL (PDX-ALL) models with dependencies on fms-like tyrosine kinase 3 (FLT3) and platelet-derived growth factor receptor β (PDGFRB), which were interrogated by phosphoproteomics using iTRAQ mass spectrometry. Signaling circuits were determined by receptor type and cellular context with few generic features, among which we identified group I p21-activated kinases (PAKs) as potential therapeutic targets. Growth factor stimulation markedly increased catalytic activities of PAK1 and PAK2. RNA interference (RNAi)-mediated or pharmacological inhibition of PAKs using allosteric or adenosine triphosphate (ATP)-competitive compounds attenuated cell growth and increased apoptosis in vitro. Notably, PAK1- or PAK2-directed RNAi enhanced the antiproliferative effects of the type III RTK and protein kinase C inhibitor midostaurin. Treatment of FLT3- or PDGFRB-dependent ALLs with ATP-competitive PAK inhibitors markedly decreased catalytic activities of both PAK isoforms. In FLT3-driven ALL, this effect was augmented by coadministration of midostaurin resulting in synergistic effects on growth inhibition and apoptosis. Finally, combined treatment of PDX-ALL with the ATP-competitive group I PAK inhibitor FRAX486 and midostaurin in vivo significantly prolonged leukemia progression-free survival compared with midostaurin monotherapy or control. Our study establishes PAKs as potential downstream targets in RTK-dependent ALL of childhood, the inhibition of which might help prevent the selection or acquisition of resistance mutations toward tyrosine kinase inhibitors.
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Article: Journal article
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Scientific Article
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Publication Year
2018
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2018
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2473-9529
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2473-9537
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Volume: 2,
Issue: 19,
Pages: 2554-2567
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American Society of Hematology
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Washington, DC
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Peer reviewed
Institute(s)
Research Unit Apoptosis in Hematopoietic Stem Cells (AHS)
POF-Topic(s)
30204 - Cell Programming and Repair
Research field(s)
Stem Cell and Neuroscience
PSP Element(s)
G-506600-001
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Erfassungsdatum
2018-10-23