Ethacrynic acid, a diuretic, functions as an inhibitor of L-type voltage-dependent and store-operated calcium channels, facilitating the relaxation of airway smooth muscle (ASM) cells. It exhibits anti-inflammatory effects, notably reducing retinoid-induced ear edema in mice, and inhibits glutathione S-transferases (GSTs), making it a potent suppressor of the NF-kB signaling pathway. Additionally, ethacrynic acid modulates leukotriene formation. A variant, Ethacrynic acid D5, is distinguished by its deuterium labeling.
Carboxyamidotriazole is a cytostatic inhibitor of non-voltage-operated calcium channels and calcium channel-mediated signaling pathways. It shows anti-inflammatory, anti-tumor, and antiangiogenic effects.
Nafoxidine is a partial estrogen antagonist. It inhibits angiogenesis in some tissues by blocking the effects of VEGF and FGF; paradoxically, it may enhance angiogenesis in uterine tissue. Nafoxidine also induces calciumsignaling, oxidative stress, and p
Protein kinase C (PKC ) is a calcium-independent, phospholipid- and diacylglycerol-dependent serine threonine kinase involved in diverse signaling pathways, including those involved in neuronal signaling, cytoskeletal function, and inflammation.[1] PKC inhibitor peptide is a synthetic peptide corresponding to an amino acid sequence found in the amino terminal C2 domain of most mammalian forms of PKC .[2] It selectively and reversibly inhibits the translocation of PKC to intracellular membranes, blocking activation.[2] PKC inhibitor peptide is commonly used in cells to evaluate the role of PKC in various cellular responses.[3],[4],[5]
Protein tyrosine phosphatases (PTPs) remove phosphate from tyrosine residues of cellular proteins. Reversible phosphorylation catalyzed by the coordinated actions of protein tyrosine kinases and phosphatases is key to the regulation of the signaling events that control cell growth and proliferation, differentiation, and survival or apoptosis, as well as adhesion and motility. RK-682, a bioactive compound originally isolated from the fermentation of Streptomyces sp. 88-682, is an inhibitor of the PTPs. It inhibits the phosphorylation of CD45 and VHR with IC50 values of 54 and 2 μM, respectively, and arrests cell cycle progress at the G1/S transition. It is also reported to inhibit heparanase (IC50 = 17 μM), an endo-β-D-glucuronidase involved in tumor cell invasion and angiogenesis. RK-682 (calcium salt) is a less soluble version of the free acid.
The phospholipases are an extensive family of lipid hydrolases that function in cell signaling, digestion, membrane remodeling, and as venom components. The calcium-independent phospholipases (iPLA2) are a PLA2 subfamily closely associated with the release of arachidonic acid in response to physiologic stimuli. (R)-Bromoenol lactone ((R)-BEL) is an irreversible, chiral, mechanism-based inhibitor of calcium-independent phospholipase γ (iPLA2γ). Unlike (S)-BEL, (R)-BEL does not inhibit iPLA2β except at high doses of 20-30 μM. (R)-BEL inhibits human recombinant iPLA2γ with an IC50 of approximately 0.6 μM.
The group IVA phospholipase A2 (PLA2), known as calcium-dependent cytosolic PLA2 (cPLA2), selectively releases arachidonic acid from membrane phospholipids, playing a central role in initiating the synthesis of prostaglandins and leukotrienes. AX 048 is a potent group IVA cPLA2 inhibitor that demonstrates 50% inhibition of the enzyme at a mole fraction (XI(50)) of 0.022. Pretreatment with AX 048 (ED50 = 1.2 mg kg) dose-dependently reduces thermal hyperalgesia evoked by carrageenan injection of rat hind paw. At concentrations as high as 30 μM, AX 048 does not inhibit COX activity or interfere with central cannabinoid receptor signaling.
Interleukin-2-inducible T cell kinase (ITK) is a non-receptor tyrosine kinase expressed in T cells, NKT cells and mast cells which plays a crucial role in regulating the T cell receptor (TCR), CD28, CD2, chemokine receptor CXCR4, and FcepsilonR-mediated signaling pathways. ITK inhibitors can be used for the treatment of inflammation and immune-mediated disorders. ITK inhibitor (N-[5-[[3-[(4-Acetylpiperazin-1-yl)carbonyl]-4-methyl-6-methoxy-phenyl]thio]thiazol-2-yl]-4-(N-1,2-dimethylpropylaminomethyl)benzamide) is the analogue of BMS-509744, which can potently and selectively inhibit Itk kinase activity. In vitro: BMS-509744 could reduce TCR-induced functions including PLCγ1 tyrosine phosphorylation, calcium mobilization, IL-2 secretion, and T-cell proliferation in vitro in both human and mouse cells [1]. In vivo: BMS-509744 suppressed the production of IL-2 induced by anti-TCR antibody administered to mice. BMS-509744 also significantly diminishes lung inflammation in a mouse model of ovalbumin-induced allergy/asthma [1]. Clinical trial: Up to now, both BMS-509744 and ITK inhibitor is still in the preclinical development stage.
Cyclic ADP-ribose (cADP-ribose) is a calcium mobilizing nucleotide that is biosynthesized from NAD+ by cADP-ribose synthases, including CD38. cADP-Ribose appears to activate calcium channels in intracellular membranes, which in turn activate ryanodine receptors. 8-bromo-cADP-Ribose is a stable, cell-permeable analog that blocks calcium release evoked by cADP-ribose in sea urchin egg homogenates with an IC50 value of 1.7 μM. It is commonly used to investigate intracellular signaling through cADP-ribose in isolated cells and tissues.
TLQP-21 TFA, a VGF-derived peptide endowed of endocrine and extraendocrine properties, is a potent G-protein-coupled receptor complement-3a receptor1 (C3aR1) agonist (EC50: mouse TLQP-21=10.3 μM; human TLQP-21=68.8μM). TLQP-21 TFA activates C3aR1 to induce an increase of intracellular Ca2+. TLQP-21 TFA is used for the research in regulation of nociception and other relevant physiologic functions[1][2]. TLQP-21 TFA is a peptide of 21 amino acids. At a dose of 3 μM TLQP-21 induces up to ~69% of the corresponding contraction promoted by acetylcholine[1][2]. [1]. Elena Bresciani , et al. TLQP-21, A VGF-Derived Peptide Endowed of Endocrine and Extraendocrine Properties: Focus on In Vitro CalciumSignaling. Int J Mol Sci. 2019 Dec 24;21(1):130. [2]. Cheryl Cero, et al. The TLQP-21 Peptide Activates the G-protein-coupled Receptor C3aR1 via a Folding-Upon-Binding Mechanism. ructure. 2014 Dec 2;22(12):1744-1753.