title: DYRK1B blocks canonical and promotes non-canonical Hedgehog signaling through activation of the mTOR/AKT pathway.
abstract: Hedgehog (Hh) signaling plays important roles in embryonic development and in tumor formation. Apart from the well-established stimulation of the GLI family of transcription factors, Hh ligands promote the phosphorylation and activation of mTOR and AKT kinases, yet the molecular mechanism underlying these processes are unknown. Here, we identify the DYRK1B kinase as a mediator between Hh signaling and mTOR/AKT activation. In fibroblasts, Hh signaling induces DYRK1B protein expression, resulting in activation of the mTOR/AKT kinase signaling arm. Furthermore, DYRK1B exerts positive and negative feedback regulation on the Hh pathway itself: It negatively interferes with SMO-elicited canonical Hh signaling, while at the same time it provides positive feed-forward functions by promoting AKT-mediated GLI stability. Due to the fact that the mTOR/AKT pathway is itself subject to strong negative feedback regulation, pharmacological inhibition of DYRK1B results in initial upregulation followed by downregulation of AKT phosphorylation and GLI stabilization. Addressing this issue therapeutically, we show that a pharmacological approach combining a DYRK1B antagonist with an mTOR/AKT inhibitor results in strong GLI1 targeting and in pronounced cytotoxicity in human pancreatic and ovarian cancer cells.
authors.affiliation: Philipps University Marburg, Institute of Molecular Biology and Tumor Research (IMT), Center for Tumor- and Immunobiology, 35043 Marburg, Germany.
authors.forename: Rajeev
authors.initials: R
authors.lastname: Singh
authors.affiliation: Philipps University Marburg, Institute of Molecular Biology and Tumor Research (IMT), Center for Tumor- and Immunobiology, 35043 Marburg, Germany.
authors.forename: Pavan Kumar
authors.initials: PK
authors.lastname: Dhanyamraju
authors.affiliation: Philipps University Marburg, Institute of Molecular Biology and Tumor Research (IMT), Center for Tumor- and Immunobiology, 35043 Marburg, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Lauth
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D053823:Hedgehog Proteins / Q000378:metabolism*; D006801:Humans; D051379:Mice; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D055550:Protein Stability; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D015398:Signal Transduction; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism*; D000071676:Zinc Finger Protein GLI1 / Q000378:metabolism; D000097603:Dyrk Kinases
chemical_list: D053823:Hedgehog Proteins; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D011505:Protein-Tyrosine Kinases; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases; D000071676:Zinc Finger Protein GLI1; D000097603:Dyrk Kinases
keywords: AKT; DYRK1B; GLI1; MIRK; hedgehog