Evaluation of [3-(1-methyl-1H-indol-3-yl-methylene)-2-oxo-2, 3-dihydro-1H-indole-5-sulfonamide] (OXSI-2), as a Syk-selective inhibitor in platelets.
In the present study, we characterized OXSI-2 [3-(1-Methyl-1H-indol-3-yl-methylene)-2-oxo-2, 3-dihydro-1H-indole-5-sulfonamide], a putative inhibitor of Syk, and determined its specificity and selectivity in platelets. We found that OXSI-2 completely abolished convulxin-induced platelet functional responses. In order to determine whether OXSI-2 inhibited Src family kinase-mediated platelet responses, we evaluated its effect on Src family kinase (SFK)-mediated signaling events in platelets, viz. Lyn-mediated phosphorylation of Y352 on Syk, LAT-Y191 phosphorylation by Syk, and protease-activated receptor (PAR)-mediated phosphorylation of ERK. In the present work, we report that convulxin mediated Syk tyrosine 352 phosphorylation is not inhibited by OXSI-2, whereas piceatannol and PP2 abolished it. Syk-mediated Y191 LAT phosphorylation is abolished by all the three inhibitors. AYPGKF-induced phosphorylation of ERK was marginally inhibited by OXSI-2, whereas treatment with PP2 and piceatannol completely abolished it. However, PAR-mediated thromboxane generation (an event mediated by ERK) was potentiated by OXSI-2 whereas PP2 and piceatannol brought thromboxane to basal levels. Protein kinase C (PKC) inhibitors are known to potentiate PAR-mediated thromboxane generation in platelets. In contrast, OXSI-2, unlike PKC inhibitors, did not inhibit secretion. Therefore, we conclude that OXSI-2 is not a Syk-selective inhibitor in platelets because of its unexplained non-specific effects.
Bhavaraju
Kamala
K
Department of Physiology, Temple University, School of Medicine, Philadelphia, PA, USA.
Kim
Soochong
S
Daniel
James L
JL
Kunapuli
Satya P
SP
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D001792:Blood Platelets / Q000187:drug effects* / Q000201:enzymology; D015153:Blotting, Western; D003435:Crotalid Venoms / Q000494:pharmacology; D003594:Cytoplasmic Granules / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006801:Humans; D007211:Indoles / Q000737:chemistry / Q000494:pharmacology*; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D037181:Lectins, C-Type; D008301:Maleimides / Q000494:pharmacology; D008565:Membrane Proteins / Q000378:metabolism; D009842:Oligopeptides / Q000494:pharmacology; D051966:Phospholipase C gamma / Q000037:antagonists & inhibitors / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D010979:Platelet Function Tests; D011494:Protein Kinases / Q000494:pharmacology; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D013267:Stilbenes / Q000494:pharmacology; D013449:Sulfonamides / Q000737:chemistry / Q000494:pharmacology*; D000072377:Syk Kinase; D013931:Thromboxanes / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism; D019061:src-Family Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism
C529168:3-(1-methyl-1H-indol-3-ylmethylene)-2-oxo-2,3-dihydro-1H-indole-5-sulfonamide; D048868:Adaptor Proteins, Signal Transducing; D003435:Crotalid Venoms; D004791:Enzyme Inhibitors; D007211:Indoles; D047908:Intracellular Signaling Peptides and Proteins; C110810:LAT protein, human; D037181:Lectins, C-Type; D008301:Maleimides; D008565:Membrane Proteins; D009842:Oligopeptides; D013267:Stilbenes; D013449:Sulfonamides; D013931:Thromboxanes; C455901:alanyl-tyrosyl-prolyl-glycyl-lysyl-phenylalanine; C028890:convulxin; D014443:Tyrosine; C041525:3,3',4,5'-tetrahydroxystilbene; D011494:Protein Kinases; D011505:Protein-Tyrosine Kinases; C000606896:SYK protein, human; D000072377:Syk Kinase; D019061:src-Family Kinases; D048049:Extracellular Signal-Regulated MAP Kinases; D051966:Phospholipase C gamma; C070515:bisindolylmaleimide I