title: Multivalent benzene polyphosphate derivatives are non-Ca2+-mobilizing Ins(1,4,5)P3receptor antagonists.
abstract: Inositol 1,4,5-trisphosphate [Ins(1,4,5)P31] mobilizes intracellular Ca2+through the Ins(1,4,5)P3receptor [InsP3R]. Although some progress has been made in the design of synthetic InsP3R partial agonists and antagonists, there are still few examples of useful small molecule competitive antagonists. A "multivalent" approach is explored and new dimeric polyphosphorylated aromatic derivatives were designed, synthesized and biologically evaluated. The established weak InsP3R ligand benzene 1,2,4-trisphosphate [Bz(1,2,4)P32] is dimerized through its 5-position in two different ways, first directly as the biphenyl derivative biphenyl 2,2',4,4',5,5'-hexakisphosphate, [BiPh(2,2',4,4',5,5')P68] and with its regioisomeric biphenyl 3,3',4,4',5,5'-hexakisphosphate [BiPh(3,3',4,4',5,5')P611]. Secondly, a linker motif is introduced in a flexible ethylene-bridged dimer (9) with its corresponding 1,2-bisphosphate dimer (10), both loosely analogous to the very weak antagonist 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA7). In permeabilized L15 fibroblasts overexpressing type 1 InsP3R, BiPh(2,2',4,4',5,5')P6(8) inhibits Ins(1,4,5)P3-induced Ca2+release in a apparently competitive fashion [IC50187 nM] and the Bz(1,2,4)P3dimer (9) is only slightly weaker [IC50380 nM]. Compounds were also evaluated against type I Ins(1,4,5)P35-phosphatase. All compounds are resistant to dephosphorylation, with BiPh(2,2',4,4',5,5')P6(8), being the most effective inhibitor of any biphenyl derivative synthesized to date [IC50480 nM] and the Bz(1,2,4)P3ethylene dimer (9) weaker [IC503.55 μM]. BiPh(3,3',4,4',5,5')P6(11) also inhibits 5-phosphatase [IC50730 nM] and exhibits unexpected Ca2+releasing activity [EC50800 nM]. Thus, relocation of only a single mirrored phenyl phosphate group in (11) from that of antagonist (8) does not markedly change enzyme inhibitory activity, but elicits a dramatic switch in Ca2+-releasing activity. Such new agents demonstrate the power of the multivalent approach and may be useful to investigate the chemical biology of signaling through InsP3R and as templates for further design.
authors.affiliation: Wolfson Laboratory of Medicinal Chemistry, Department of Pharmacy and Pharmacology, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Mills
authors.affiliation: Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, Campus Gasthuisberg O/N-1, Herestraat 49, Bus 802, 3000 Leuven, Belgium.
authors.forename: Tomas
authors.initials: T
authors.lastname: Luyten
authors.affiliation: Institut de Recherche Interdisciplinaire (IRIBHM), Université Libre de Bruxelles, Campus Erasme, Brussels, Belgium.
authors.forename: Christophe
authors.initials: C
authors.lastname: Erneux
authors.affiliation: Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, Campus Gasthuisberg O/N-1, Herestraat 49, Bus 802, 3000 Leuven, Belgium.
authors.forename: Jan B
authors.initials: JB
authors.lastname: Parys
authors.affiliation: Wolfson Laboratory of Medicinal Chemistry, Department of Pharmacy and Pharmacology, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
authors.forename: Barry V L
authors.initials: BV
authors.lastname: Potter
keywords: Ins(1,4,5)P3 receptor; antagonist; benzene polyphosphate; biphenyl polyphosphate; competitive inhibition
references.citation: Neuron. 1990 Jul;5(1):11-8
references.pmid: 2164403
references.citation: Eur J Pharmacol. 1993 Feb 15;244(3):203-10
references.pmid: 8384566
references.citation: Pflugers Arch. 1993 Sep;424(5-6):516-22
references.pmid: 8255736
references.citation: Nature. 2012 Jan 29;483(7387):108-12
references.pmid: 22286060
references.citation: J Med Chem. 1994 Apr 1;37(7):907-12
references.pmid: 8151617
references.citation: Chembiochem. 2008 Jul 21;9(11):1757-66
references.pmid: 18574825
references.citation: Mol Pharmacol. 1993 Apr;43(4):499-503
references.pmid: 8386304
references.citation: FASEB J. 2002 Aug;16(10):1145-50
references.pmid: 12153982
references.citation: Cell. 1987 Dec 24;51(6):919-28
references.pmid: 3319190
references.citation: Physiol Rev. 2007 Apr;87(2):593-658
references.pmid: 17429043
references.citation: Cell Calcium. 1999 Feb;25(2):137-42
references.pmid: 10326680
references.citation: J Biol Chem. 1993 Jun 5;268(16):11528-33
references.pmid: 8389355
references.citation: J Biol Chem. 1993 Nov 25;268(33):25206-12
references.pmid: 8227085
references.citation: Biochem Biophys Res Commun. 1986 Jan 14;134(1):351-8
references.pmid: 3004437
references.citation: J Biol Chem. 1994 Mar 11;269(10):7238-42
references.pmid: 8125936
references.citation: Nature. 1992 Jun 18;357(6379):599-602
references.pmid: 1608471
references.citation: FASEB J. 2007 May;21(7):1481-91
references.pmid: 17264160
references.citation: Chem Commun (Camb). 2011 Jan 7;47(1):242-4
references.pmid: 20938532
references.citation: Bioorg Med Chem. 1994 Apr;2(4):253-7
references.pmid: 7922136
references.citation: Nature. 2000 Dec 7;408(6813):735-40
references.pmid: 11130077
references.citation: J Biol Chem. 1995 May 19;270(20):12075-84
references.pmid: 7744856
references.citation: Pflugers Arch. 2003 Mar;445(6):629-42
references.pmid: 12632182
references.citation: Bioconjug Chem. 2004 Mar-Apr;15(2):278-89
references.pmid: 15025523
references.citation: Chembiochem. 2006 Nov;7(11):1696-706
references.pmid: 16964627
references.citation: Mol Pharmacol. 2000 Mar;57(3):595-601
references.pmid: 10692501
references.citation: Eur J Biochem. 1989 May 1;181(2):317-22
references.pmid: 2540972
references.citation: Nat Struct Mol Biol. 2011 Sep 04;18(10):1172-4
references.pmid: 21892169
references.citation: Nat Chem Biol. 2009 Sep;5(9):631-9
references.pmid: 19668195
references.citation: Nature. 2002 Dec 12;420(6916):696-700
references.pmid: 12442173
references.citation: Cell Calcium. 2010 Apr;47(4):297-314
references.pmid: 20189643
references.citation: Am J Physiol Cell Physiol. 2009 Nov;297(5):C1133-45
references.pmid: 19692655
references.citation: J Biol Chem. 2002 Sep 20;277(38):35061-70
references.pmid: 12121980
references.citation: Nature. 1984 Nov 22-28;312(5992):374-6
references.pmid: 6095097
references.citation: Biochem Soc Trans. 2007 Feb;35(Pt 1):109-14
references.pmid: 17233614
references.citation: Biochem J. 1994 May 15;300 ( Pt 1):85-90
references.pmid: 8198557
references.citation: J Biol Chem. 2002 Oct 25;277(43):40290-5
references.pmid: 12183463