pt 100

Talabostat (PT100, Val-boroPro) is a potent, nonselective and orally available dipeptidyl peptidase IV (DPP-IV) inhibitor with a Ki of 0.18 nM. Talabostat is a nonselective DPP-IV inhibitor, inhibiting DPP8/9, FAP, DPP2 and some other DASH family enzymes essentially as potently as it inhibits DPP-IV[1]. Talabostat stimulates the immune system by triggering a proinflammatory form of cell death in monocytes and macrophages known as pyroptosis. The inhibition of two serine proteases, DPP8 and DPP9, activates the proprotein form of caspase-1 independent of the inflammasome adaptor ASC[2]. Talabostat competitively inhibits the dipeptidyl peptidase (DPP) activity of FAP and CD26/DPP-IV, and there is a high-affinity interaction with the catalytic site due to the formation of a complex between Ser630/624 and the boron of talabostat[3]. Talabostat can stimulate immune responses against tumors involving both the innate and adaptive branches of the immune system. In WEHI 164 fibrosarcoma and EL4 and A20/2J lymphoma models, PT-100 causes regression and rejection of tumors. The antitumor effect appears to involve tumor-specific CTL and protective immunological memory. Talabostat treatment of WEHI 164-inoculated mice increases mRNA expression of cytokines and chemokines known to promote T-cell priming and chemoattraction of T cells and innate effector cells[3]. Talabostat treated mice show significant less fibrosis and FAP expression is reduced. Upon PT100 treatment, significant differences in the MMP-12, MIP-1α, and MCP-3 mRNA expression levels in the lungs are also observed. Treatment with PT100 in this murine model of pulmonary fibrosis has an anti-fibro-proliferative effect and increases macrophage activation[4]. [1]. Connolly BA, et al. Dipeptide boronic acid inhibitors of dipeptidyl peptidase IV: determinants of potencyand in vivo efficacy and safety. J Med Chem. 2008 Oct 9;51(19):6005-13. [2]. Okondo MC, et al. DPP8 and DPP9 inhibition induces pro-caspase-1-dependent monocyte and macrophage pyroptosis. Nat Chem Biol. 2017 Jan;13(1):46-53. [3]. Adams S, et al. PT-100, a small molecule dipeptidyl peptidase inhibitor, has potent antitumor effects and augments antibody-mediated cytotoxicity via a novel immune mechanism. Cancer Res. 2004 Aug 1;64(15):5471-80. [4]. Egger C, et al. Effects of the fibroblast activation protein inhibitor, PT100, in a murine model of pulmonary fibrosis. Eur J Pharmacol. 2017 Aug 15;809:64-72.

Talabostat mesylate (PT100) is an orally active, selective inhibitor of dipeptidyl peptidases IV (DPP4, IC50: 0.18 nM), including tumor-associated fibroblast activation protein. This agent may also stimulate the production of colony stimulating factors, such as granulocyte colony-stimulating factor (G-CSF), resulting in the stimulation of hematopoiesis.

PAR2 (1-6) amide is a synthetic peptide agonist of proteinase-activated receptor 2 (PAR2) that corresponds to residues 1-6 of the amino terminal tethered ligand sequence of human PAR2 and residues 37-42 of the full-length sequence.1It binds to NCTC 2544 cells expressing human PAR2 (Ki= 9.64 μM in a radioligand binding assay) and induces calcium mobilization in the same cells (EC50= 0.075 μM).2PAR2 (1-6) amide (100 μM) reduces colony formation of A549 lung cancer cells.1It induces superoxide production and degranulation in isolated human eosinophils when used at a concentration of 500 μM.3PAR2 (1-6) amide (5 μmol/kg) induces tear secretion in rats when used in combination with amastatin .4 1.Bohm, S.K., Kong, W., Bromme, D., et al.Molecular cloning, expression and potential functions of the human proteinase-activated receptor-2Biochem. J.314(Pt 3)1009-1016(1996) 2.Kanke, T., Ishiwata, H., Kabeya, M., et al.Binding of a highly potent protease-activated receptor-2 (PAR2) activating peptide, [3H]2-furoyl-LIGRL-NH2, to human PAR2Br. J. Pharmacol.145(2)255-263(2005) 3.Miike, S., McWilliam, A.S., and Kita, H.Trypsin induces activation and inflammatory mediator release from human eosinophils through protease-activated receptor-2J. Immunol.167(11)6615-6622(2001) 4.Nishikawa, H., Kawai, K., Tanaka, M., et al.Protease-activated receptor-2 (PAR-2)-related peptides induce tear secretion in rats: Involvement of PAR-2 and non-PAR-2 mechanismsJ. Pharmacol. Exp. Ther.312(2)324-331(2005)

Guanosine 5’-diphosphate (GDP) is a purine nucleotide and biosynthetic precursor of guanosine 5’-triphosphate .1It has been used to study the conformations of GTPases.2GDP (100 μM) activates sulfonylurea receptor 2B (SUR2B) linked to the inward-rectifier potassium channel 6.1 (Kir6.1) in HEK293T cells in a patch-clamp assay.3 1.Berg, J.M., Tymoczko, J.L., and Stryer, L.Biochemistry(2002) 2.Vetter, I.R., and Wittinghofer, A.The guanine nucleotide-binding switch in three dimensionsScience294(5545)1299-1304(2001) 3.Yamada, M., Isomoto, S., Matsumoto, S., et al.Sulphonylurea receptor 2B and Kir6.1 form a sulphonylurea-sensitive but ATP-insensitive K+ channelJ. Physiol.499(Pt 3)715-720(1997)

Palmitoylcholine is an acyl choline.1It inhibits protein kinase C activity when used at a concentration of 100 μM.2Palmitoylcholine induces hemolysis in rat erythrocytes.3Plasma levels of palmitoylcholine are decreased in female patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).1 1.Germain, A., Barupal, D.K., Levine, S.M., et al.Comprehensive circulatory metabolomics in ME/CFS reveals disrupted metabolism of acyl lipids and steroidsMetabolites10(1)34(2020) 2.Nakadate, T., and Blumberg, P.M.Modulation by palmitoylcarnitine of protein kinase C activationCancer Res.47(24 Pt 1)6537-6542(1987) 3.Cho, K.S., and Proulx, P.Interactions of acyl carnitines and other lysins with erythrocytes and reconstituted erythrocyte lipoproteinsBiochim. Biophys. Acta318(1)50-60(1973)

PAR2 (1-6) is a synthetic peptide agonist of proteinase-activated receptor 2 (PAR2) that corresponds to residues 1-6 of the amino terminal tethered ligand sequence of mouse and rat PAR2. It also corresponds to residues 39-44 and 37-42 of the mouse and rat full-length sequences, respectively. PAR2 (1-6) induces relaxation in precontracted rat arteries in a concentration-dependent manner, an effect that can be reduced by the nitric oxide synthase inhibitor L-NNA . It inhibits keratinocyte growth in the presence and absence of growth factors. PAR2 (1-6) inhibits LPS-induced pulmonary neutrophil influx and increases in matrix metalloproteinase-2 (MMP-2) activity in mice.