Document text
Principal Investigator: Wei Tong
Organization: CHILDREN'S HOSP OF PHILADELPHIA
Fiscal Year: 2024
Award: $604,938
Funding agency: National Cancer Institute
Summary
The temporal and spatial distribution of signaling proteins is dynamically regulated by post-translational
modifications (PTMs). PTMs such as phosphorylation, ubiquitination, or lipid modification dictate protein activities
and access to substrates, thereby cellular outcomes. The precise control of signaling pathways is critical to
normal hematopoiesis and aberrant signaling leads to malignant transformation of hematopoietic stem and
progenitor cells (HSPCs). This application is based on our novel finding that FLT3 (FMS-like tyrosine kinase 3)
is palmitoylated and disrupting palmitoylation of oncogenic FLT3 mutants changes their subcellular localization,
rewires downstream signaling, and promotes leukemic progression. Internal tandem duplication within FLT3
(FLT3-ITD) is one of the most frequent mutations in acute myeloid leukemia (AML) and correlates with poor
prognosis. While wildtype FLT3 receptor tyrosine kinase is activated at the plasma membrane to transduce
PI3K/AKT and RAS/MAPK signaling, FLT3-ITD resides in the endoplasmic reticulum (ER) and triggers
constitutive STAT5 phosphorylation. Mechanisms underlying this aberrant FLT3-ITD subcellular localization or
its impact on leukemogenesis remain poorly understood. We discovered that FLT3-ITD is S-palmitoylated by the
ZDHHC6 acyltransferase. Disruption of palmitoylation redirects FLT3-ITD to the plasma membrane and rewires
its downstream signaling by activating AKT and ERK pathways in addition to STAT5. Consequently, abrogation
of FLT3-ITD palmitoylation via ZDHHC6 depletion promotes FLT3-ITD surface expression, signaling, and
increased leukemic progression in xenotransplanted mouse models. Furthermore, we demonstrate that FLT3
proteins are palmitoylated in primary human AML cells. Stabilization of FLT3-ITD palmitoylation by
pharmacological inhibition of depalmitoylation synergizes with FLT3 tyrosine kinase inhibitor (TKI) gilteritinib in
abrogating the growth of primary FLT3-ITD+ AML cells. The central goal of this grant is to define the molecular
basis underlying the regulation of oncogenic FLT3 signaling by palmitoylation and explore its physiological and
functional significance in myeloid malignancies. We propose to define roles of ZDHHC6 in FLT3-ITD
palmitoylation in vivo in mouse models of myeloproliferative neoplasm (MPN) and AML. We will also identify
depalmitoylase(s) for FLT3-ITD that modify FLT3-ITD localization, and activity using combinatorial approaches
of targeted and unbiased chemical biology, molecular biology, and genetics. Moreover, we will explore the
therapeutic potential of targeting FLT3-ITD depalmitoylation in primary human FLT3-ITD+ AMLs. We will
investigate if inhibition of FLT3-ITD depalmitoylase enhances responses to TKI using primary human AML cells
as well as patient-derived xenotransplant (PDX) models. These findings provide novel insights into lipid-
dependent compartmentalization of FLT3-ITD signaling and suggest targeting depalmitoylation as a new
therapeutic strategy to treat FLT3-ITD+ leukemias.
Terms: <1-Phosphatidylinositol 3-Kinase><AKT><AML - Acute Myeloid Leukemia><Acute Myeloblastic Leukemia><Acute Myelocytic Leukemia><Acute Myelogenous Leukemia><Acyltransferase><Akt protein><Binding><Biology><Blood Precursor Cell><Breeding><Cell Communication and Signaling><Cell Line><Cell Signaling><Cell membrane><CellLine><Cellular Expansion><Cellular Growth><Chemicals><Collaborations><Cysteine><Cytoplasmic Membrane><DNA Molecular Biology><DNMT3a><Disease><Disorder><EC 2.3><EPH- and ELK-Related Tyrosine Kinase><EPH-and ELK-Related Kinase><Endoplasmic Reticulum><Enzyme Gene><Enzymes><Ephrin Type-A Receptor 8><Ephrin Type-A Receptor 8 Precursor><Equilibrium><Ergastoplasm><Extracellular Signal-Regulated Kinase Gene><FLK2><FLT3><FLT3 gene><FMS-like tyrosine kinase 3><Fms-Related Tyrosine Kinase 3><Generalized Growth><Genetic><Genetic Alteration><Genetic Change><Genetic defect><Goals><Grant><Growth><Half-Cystine><Hematopoiesis><Hematopoietic Cellular Control Mechanisms><Hematopoietic Progenitor Cells><Hematopoietic stem cells><Heterograft><Heterologous Transplantation><Human><Impairment><Intracellular Communication and Signaling><KI mice><Knock-in Mouse><L-Cysteine><Leukemic Cell><Ligands><Lipids><MAP Kinase Gene><MAPK><MGF protein><MGSNF protein><Malignant><Malignant - descriptor><Mediating><Mice><Mice Mammals><Minor><Minority><Mitogen-Activated Protein Kinase Gene><Modeling><Modern Man><Modification><Molecular><Molecular Biology><Molecular Interaction><Murine><Mus><Mutate><Mutation><Myeloid Disease><Myeloid Malignancy><Myeloid Neoplasm><Myeloid Tumor><Myeloproliferative Disorders><Myeloproliferative Tumors><Myeloproliferative disease><Oncogenic><Outcome><PI-3 Kinase><PI-3K/AKT><PI3-Kinase><PI3CG><PI3K/AKT><PI3KGamma><PI3k><PIK3><PIK3CG><PIK3CG gene><PTK Inhibitors><PTK Receptors><Pathway interactions><Patients><Pharmacological Study><Pharmacology Study><Phosphatidylinositol 3-Kinase><Phosphatidylinositol-3-OH Kinase><Phosphoinositide 3-Hydroxykinase><Phosphorylation><Physiologic><Physiological><Plasma Membrane><Post-Translational Modification Protein/Amino Acid Biochemistry><Post-Translational Modifications><Post-Translational Protein Modification><Post-Translational Protein Processing><Posttranslational Modifications><Posttranslational Protein Processing><Prognosis><Proliferating><Protein Kinase B><Protein Modification><Protein Phosphorylation><Protein Tyrosine Kinase><Protein Tyrosine Kinase EEK><Protein Tyrosine Kinase Inhibitors><Proteins><Proteomics><Proto-Oncogene Proteins c-akt><PtdIns 3-Kinase><RAC-PK protein><Receptor Protein-Tyrosine Kinases><Receptor Tyrosine Kinase Gene><Regulation><Relapse><Role><STAT5><STAT5A><STAT5A gene><STAT5a Transcription Factor><STK-1 kinase><STK1><Signal Pathway><Signal Transducer and Activator of Transcription 5A><Signal Transduction><Signal Transduction Systems><Signaling><Signaling Factor Proto-Oncogene><Signaling Pathway Gene><Signaling Protein><Spatial Distribution><Stat5 protein><Stat5a protein><Stat5alpha protein><Stem Cell Tyrosine Kinase 1><Strains Cell Lines><Surface><TK Inhibitors><Therapeutic><Tissue Growth><Transmembrane Receptor Protein Tyrosine Kinase><Type I Phosphatidylinositol Kinase><Type III Phosphoinositide 3-Kinase><Tyrosine Kinase><Tyrosine Kinase Inhibitor><Tyrosine Kinase Linked Receptors><Tyrosine Kinase Receptors><Tyrosine-Protein Kinase Receptor EEK><Tyrosine-Specific Protein Kinase><Tyrosylprotein Kinase><Ubiquitilation><Ubiquitination><Ubiquitinoylation><Work><Xenograft><Xenograft Model><Xenograft procedure><Xenotransplantation><acute granulocytic leukemia><acute granulocytic leukemia cell><acute myeloblastic leukemia cell><acute myelocytic leukemia cell><acute myelogenous leukemia cell><acute myeloid leukemia><acute myeloid leukemia cell><acute nonlymphocytic leukemia cell><balance><balance function><biological signal transduction><blood cell formation><blood cell progenitor><blood progenitor><blood stem cell><blood-forming stem cell><c-akt protein><cell growth><clinical relevance><clinical significance><clinically relevant><clinically significant><combinatorial><cultured cell line><fetal liver kinase-2><fetal liver kinase-3><genetic approach><genetic strategy><genome mutation><hDNA methyltransferase 3a><hematopoietic progenitor><hematopoietic stem progenitor cell><hemopoietic progenitor><hemopoietic stem cell><hydroxyaryl protein kinase><in vivo><in vivo Model><inhibitor><innovate><innovation><innovative><insight><knockin mice><leukemia><leukemogenesis><mammary gland factor><mammary gland-specific nuclear factor><mouse model><murine model><mutant><myeloproliferative neoplasm><new drug target><new drug treatments><new druggable target><new drugs><new pharmacological therapeutic><new pharmacotherapy target><new therapeutic approach><new therapeutic intervention><new therapeutic strategies><new therapeutic target><new therapeutics><new therapy><new therapy approaches><new therapy target><new treatment approach><new treatment strategy><next generation therapeutics><novel><novel drug target><novel drug treatments><novel druggable target><novel drugs><novel pharmaco-therapeutic><novel pharmacological therapeutic><novel pharmacotherapy target><novel therapeutic approach><novel therapeutic intervention><novel therapeutic strategies><novel therapeutic target><novel therapeutics><novel therapy><novel therapy approach><novel therapy target><ontogeny><palmitoylation><pathway><pharmacologic><plasmalemma><proto-oncogene protein RAC><proto-oncogene protein akt><rac protein kinase><related to A and C-protein><response><signal tranducer and activator of transcription 5><social role><synergism><targeted drug therapy><targeted drug treatments><targeted therapeutic><targeted therapeutic agents><targeted therapy><targeted treatment><tyrosyl protein kinase><ubiquination><ubiquitin conjugation><xeno-transplant><xeno-transplantation><xenograft transplant model><xenotransplant model>