title: Synthesis of a norcantharidin-tethered guanosine: Protein phosphatase-1 inhibitors that change alternative splicing.
abstract: Phosphorylation and dephosphorylation of splicing factors play a key role in pre-mRNA splicing events, and cantharidin and norcantharidin analogs inhibit protein phosphatase-1 (PP1) and change alternative pre-mRNA splicing. Targeted inhibitors capable of selectively inhibiting PP-1 could promote exon 7 inclusion in the survival-of-motorneuron-2 gene (SMN2) and shift the proportion of SMN2 protein from a dysfunctional to a functional form. As a prelude to the development of norcantharidin-tethered oligonucleotide inhibitors, the synthesis a norcantharidin-tethered guanosine was developed in which a suitable tether prevented the undesired cyclization of norcantharidin monoamides to imides and possessed a secondary amine terminus suited to the synthesis of oligonucleotides analogs. Application of this methodology led to the synthesis of a diastereomeric mixture of norcantharidin-tethered guanosines, namely bisammonium (1R,2S,3R,4S)- and (1S,2R,3S,4R)-3-((4-(2-(((((2R,3R,4R,5R)-5-(2-amino-6-oxo-1,6-dihydro-9H-purin-9-yl)-2-(hydroxymethyl)-4-methoxytetrahydrofuran-3-yl)oxy)oxidophosphoryl)oxy)ethyl)-phenethyl)(methyl)carbamoyl)-7-oxabicyclo[2.2.1]heptane-2-carboxylate, which showed activity in an assay for SMN2 pre-mRNA splicing.
authors.affiliation: Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky, Lexington, KY 40536-0509, United States; Center for Pharmaceutical Research and Innovation, College of Pharmacy, University of Kentucky, Lexington, KY 40536-0596, United States.
authors.forename: Stefan
authors.initials: S
authors.lastname: Kwiatkowski
authors.affiliation: Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky, Lexington, KY 40536-0509, United States; Center for Pharmaceutical Research and Innovation, College of Pharmacy, University of Kentucky, Lexington, KY 40536-0596, United States.
authors.forename: Vitaliy M
authors.initials: VM
authors.lastname: Sviripa
authors.affiliation: Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky, Lexington, KY 40536-0509, United States.
authors.forename: Zhaiyi
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky, Lexington, KY 40536-0509, United States.
authors.forename: Alison E
authors.initials: AE
authors.lastname: Wendlandt
authors.affiliation: Research Group Nucleic Acid Chemistry, Max Planck Institute for Biophysical Chemistry, D-37077 Göttingen, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Höbartner
authors.affiliation: Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky, Lexington, KY 40536-0509, United States; Center for Pharmaceutical Research and Innovation, College of Pharmacy, University of Kentucky, Lexington, KY 40536-0596, United States; Lucille Parker Markey Cancer Center, University of Kentucky, Lexington, KY 40536-0093, United States. Electronic address: dwatt@uky.edu.
authors.forename: David S
authors.initials: DS
authors.lastname: Watt
authors.affiliation: Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky, Lexington, KY 40536-0509, United States. Electronic address: stefan.stamm@uky.edu.
authors.forename: Stefan
authors.initials: S
authors.lastname: Stamm
mesh_terms: D017398:Alternative Splicing; D000818:Animals; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000737:chemistry*; D004791:Enzyme Inhibitors / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism; D006151:Guanosine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D054645:Protein Phosphatase 1 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D055540:Survival of Motor Neuron 2 Protein / Q000235:genetics / Q000378:metabolism
chemical_list: D019086:Bridged Bicyclo Compounds, Heterocyclic; D004791:Enzyme Inhibitors; D012333:RNA, Messenger; C000597152:SMN2 protein, mouse; D055540:Survival of Motor Neuron 2 Protein; D006151:Guanosine; C069741:norcantharidin; D054645:Protein Phosphatase 1
keywords: Alternative pre-mRNA splicing; Exon 7 inclusion; Norcantharidin analogs; Protein phosphatase-1 (PP1) inhibitors; SMN2 protein