Joseph Schlessinger

High-grade neuroendocrine cervical cancers (NETc) are exceedingly rare, highly aggressive tumors. We analyzed 64 NETc tumor samples by whole-exome sequencing (WES). Human papillomavirus DNA was detected in 65.6% (42/64) of the tumors. Recurrent mutations were identified in PIK3CA, KMT2D/MLL2, K-RAS, ARID1A, NOTCH2, and RPL10. The top mutated genes included RB1, ARID1A, PTEN, KMT2D/MLL2, and WDFY3, a gene not yet implicated in NETc. Somatic CNV analysis identified two copy number gains (3q27.1 and 19q13.12) and five copy number losses (1p36.21/5q31.3/6p22.2/9q21.11/11p15.5). Also, gene fusions affecting the ACLY-CRHR1 and PVT1-MYC genes were identified in one of the eight samples subjected to RNA sequencing. To resolve evolutionary history, multiregion WES in NETc admixed with adenocarcinoma cells was performed (i.e., mixed-NETc). Phylogenetic analysis of …

ZEOWTGPWHLSLOG-UHFFFAOYSA-N Cc1ccc (cc1-c1ccc2c (n [nH] c2c1)-c1cnn (c1) C1CC1) C (= O) Nc1cccc (c1) C (F)(F) F Chemical compound Cc1ccc (cc1-c1ccc2c (n [nH] c2c1)-c1cnn (c1) C1CC1) C (= O) Nc1cccc (c1) C (F)(F) F ZEOWTGPWHLSLOG-UHFFFAOYSA-N 0.000 description 5

YLMAHDNUQAMNNX-UHFFFAOYSA-N imatinib methanesulfonate Chemical group CS (O)(= O)= O. C1CN (C) CCN1CC1= CC= C (C (= O) NC= 2C= C (NC= 3N= C (C= CN= 3) C= 3C= NC= CC= 3) C (C)= CC= 2) C= C1 YLMAHDNUQAMNNX-UHFFFAOYSA-N 0.000 claims description 4

Growth factors and cytokines signal by binding to the extracellular domains of their receptors and drive association and transphosphorylation of the receptor intracellular tyrosine kinase domains, initiating downstream signaling cascades. To enable systematic exploration of how receptor valency and geometry affects signaling outcomes, we designed cyclic homo-oligomers with up to 8 subunits using repeat protein building blocks that can be modularly extended. By incorporating a de novo designed fibroblast growth-factor receptor (FGFR) binding module into these scaffolds, we generated a series of synthetic signaling ligands that exhibit potent valency-and geometry-dependent Ca2+ release and MAPK pathway activation. The high specificity of the designed agonists reveal distinct roles for two FGFR splice variants in driving endothelial and mesenchymal cell fates during early vascular development. The ability to …

While important insights were gained about how FGF21 and other endocrine fibroblast growth factors (FGFs) bind to Klotho proteins, the exact mechanism of Klotho/FGF receptor assembly that drives receptor dimerization and activation has not been elucidated. The prevailing dogma is that Klotho proteins substitute for the loss of heparan sulfate proteoglycan (HSPG) binding to endocrine FGFs by high-affinity binding of endocrine FGF molecules to Klotho receptors. To explore a potential role of HSPG in FGF21 signaling, we have analyzed the dynamic properties of FGF21-induced FGF21–βKlotho–FGFR1c complexes on the surface of living wild-type (WT) or HSPG-deficient Chinese hamster ovary (CHO) cells by employing quantitative single-molecule fluorescence imaging analyses. Moreover, detailed analyses of FGF21 and FGF1 stimulation of cellular signaling pathways activated in WT or in HSPG-deficient …

ObjectivesUterine leiomyosarcoma (uLMS) is a rare, highly aggressive tumor with an estimated 5-year overall survival of 50% for even early-stage disease. Up to 30% of uLMS may harbor a gain of function in the MAP2K4 gene, a member of the MAPK family which plays an important role in tumor cell proliferation, differentiation, and metastasization. We sought to investigate the in vivo activity of a novel MAP2K4 inhibitor, PLX8725, against uLMS harboring MAP2K4 gene amplification.MethodsWhole exome sequencing (WES), RNA-sequencing, and/or whole-genome sequencing were performed on a total of 83 patients from local and TCGA data; two patient-derived xenografts (PDX) had WES data abstracted. Available PDX models (LEY11 and LEY16) were grafted into female CB-17/SCID mice and triaged for treatment with a control vehicle or PLX8725 (50 mg/kg daily). Treatments were given via oral gavage …

The receptor tyrosine kinase KIT and its ligand stem cell factor (SCF) are required for the development of hematopoietic stem cells, germ cells, and other cells. A variety of human cancers, such as acute myeloid leukemia, gastrointestinal stromal tumor, and mast cell leukemia, are driven by somatic gain-of-function KIT mutations. Here, we report cryo electron microscopy (cryo-EM) structural analyses of full-length wild-type and two oncogenic KIT mutants, which show that the overall symmetric arrangement of the extracellular domain of ligand-occupied KIT dimers contains asymmetric D5 homotypic contacts juxtaposing the plasma membrane. Mutational analysis of KIT reveals in D5 region an “Achilles heel” for therapeutic intervention. A ligand-sensitized oncogenic KIT mutant exhibits a more comprehensive and stable D5 asymmetric conformation. A constitutively active ligand-independent oncogenic KIT mutant …

Probe molecules that covalently modify the JAK2 pseudokinase domain (JH2) are reported. Selective targeting of JH2 domains over the kinase (JH1) domains is a necessary feature for ligands intended to evaluate JH2 domains as therapeutic targets. The JH2 domains of three Janus kinases (JAK1, JAK2, and TYK2) possess a cysteine residue in the catalytic loop that does not occur in their JH1 domains. Starting from a non-selective kinase binding molecule, computer-aided design directed attachment of substituents terminating in acrylamide warheads to modify Cys675 of JAK2 JH2. Successful covalent attachment was demonstrated first through observation of enhanced binding with increasing incubation time in fluorescence polarization experiments. Covalent binding also increased selectivity to as much as ca. 30-fold for binding the JAK2 JH2 domain over the JH1 domain after a 20-h incubation. Covalency was …