Mitochondrial release of cytochrome c triggers apoptosis via the assembly of a multimeric complex including caspase-9, Apaf-1, and other components, sometimes called the apoptosome. Library screens have identified smallmolecules that activate the apoptosome by binding to one or more of its components. CAY10443 is one such molecule. In a cell free, multi-component assay, it activated caspase-3 with an EC50 of 5 μM. These apoptotic activators represent therapeutic lead compounds for the development of antitumor drugs.
Alaproclate is a selective serotonin reuptake inhibitor (SSRI).1,2 It inhibits depletion of serotonin (5-HT) induced by 4-methyl-α-ethyl-m-tyramine in rat cerebral cortex, hippocampus, hypothalamus, and striatum (EC50s = 18, 4, 8, and 12 mg kg, respectively).1 Alaproclate inhibits NMDA-evoked currents and depolarization-induced voltage-dependent potassium currents in rat hippocampal neurons (IC50s = 1.1 and 6.9 μM, respectively) and does not inhibit GABA-evoked currents when used at concentrations up to 100 μM.2 It increases sirtuin 1 (SIRT1) levels in N2a murine neuroblastoma cells expressing apolipoprotein E4 (ApoE4; IC50 = 2.3 μM) and in the hippocampus in the FXFAD-ApoE4 transgenic mouse model of Alzheimer's disease when administered at a dose of 20 mg kg twice daily.3 Alaproclate (40 mg kg) decreases immobility time in the forced swim test in rats, indicating antidepressant-like activity.4References1. Michael, G.B., Eidam, C., Kadlec, K., et al. Increased MICs of gamithromycin and tildipirosin in the presence of the genes erm(42) and msr(E)-mph(E) for bovine Pasteurella multocida and Mannheimia haemolytica. Journal of Antimicrobial Chemotherapy 67(6), 1555-1557 (2012).2. Svensson, B.E., Werkman, T.R., and Rogawski, M.A. Alaproclate effects on voltage-dependent K+ channels and NMDA receptors: Studies in cultured rat hippocampal neurons and fibroblast cells transformed with Kv1.2 K+ channel cDNA. Neuropharmacology 33(6), 795-804 (1994).3. Campagna, J., Soilman, P., Jagodzinska, B., et al. A smallmolecule ApoE4-targeted therapeutic candidate that normalizes sirtuin 1 levels and improves cognition in an Alzheimer's disease mouse model. Sci. Rep. 8(1), 17574 (2018).4. Danysz, W.P., A., Kostowski, W., Malatynska, E., et al. Comparison of desipramine, amitriptyline, zimeldine and alaproclate in six animal models used to investigate antidepressant drugs. Pharmacol. Toxicol. 62(1), 42-50 (1988). Alaproclate is a selective serotonin reuptake inhibitor (SSRI).1,2 It inhibits depletion of serotonin (5-HT) induced by 4-methyl-α-ethyl-m-tyramine in rat cerebral cortex, hippocampus, hypothalamus, and striatum (EC50s = 18, 4, 8, and 12 mg kg, respectively).1 Alaproclate inhibits NMDA-evoked currents and depolarization-induced voltage-dependent potassium currents in rat hippocampal neurons (IC50s = 1.1 and 6.9 μM, respectively) and does not inhibit GABA-evoked currents when used at concentrations up to 100 μM.2 It increases sirtuin 1 (SIRT1) levels in N2a murine neuroblastoma cells expressing apolipoprotein E4 (ApoE4; IC50 = 2.3 μM) and in the hippocampus in the FXFAD-ApoE4 transgenic mouse model of Alzheimer's disease when administered at a dose of 20 mg kg twice daily.3 Alaproclate (40 mg kg) decreases immobility time in the forced swim test in rats, indicating antidepressant-like activity.4 References1. Michael, G.B., Eidam, C., Kadlec, K., et al. Increased MICs of gamithromycin and tildipirosin in the presence of the genes erm(42) and msr(E)-mph(E) for bovine Pasteurella multocida and Mannheimia haemolytica. Journal of Antimicrobial Chemotherapy 67(6), 1555-1557 (2012).2. Svensson, B.E., Werkman, T.R., and Rogawski, M.A. Alaproclate effects on voltage-dependent K+ channels and NMDA receptors: Studies in cultured rat hippocampal neurons and fibroblast cells transformed with Kv1.2 K+ channel cDNA. Neuropharmacology 33(6), 795-804 (1994).3. Campagna, J., Soilman, P., Jagodzinska, B., et al. A smallmolecule ApoE4-targeted therapeutic candidate that normalizes sirtuin 1 levels and improves cognition in an Alzheimer's disease mouse model. Sci. Rep. 8(1), 17574 (2018).4. Danysz, W.P., A., Kostowski, W., Malatynska, E., et al. Comparison of desipramine, amitriptyline, zimeldine and alaproclate in six animal models used to investigate antidepressant drugs. Pharmacol. Toxicol. 62(1), 42-50 (1988).
Purfalcamine is an orally active, selective Plasmodium falciparum calcium-dependent protein kinase 1 (PfCDPK1) inhibitor with an IC50 of 17 nM and an EC50 of 230 nM. Purfalcamine has antimalarial activity and causes malaria parasites developmental arrest at the schizont stage[1][2]. Purfalcamine has low activity against Toxoplasma gondii calcium-dependent protein kinase 3 (TgCDPK3)[1]. Purfalcamine (225, 450 nM) has no effect on the parasitemia in the first 32 hours. After about 40 hours, parasite level remains stable and then begins dropping[1]. Purfalcamine inhibits proliferation with EC50s of 171-259 nM for P. falciparum strains (3D7, Dd2, FCB, HB3 and W2), which indicates effectiveness against drug-resistant parasites[1]. Given that the EC50 value for P. falciparum (3D7) is 230 nM, Purfalcamine shows a therapeutic window ranging from 23-fold to 36-fold (EC50s for CHO=12.33 μM, HEp2=7.235 μM, HeLa=7.029 μM and Huh7=5.476 μM)[1]. Purfalcamine (10 mg kg; oral gavage; BID; for 6 days) demonstrates a delay in the onset of parasitemia in treated mice[1]. Purfalcamine (20 mg kg; orally gavage) exhibits a Cmax of 2.6 μM with a half-life of 3.1 hours[1]. Animal Model: Male BALB c mice, 7 weeks of age with the malaria parasite[1] [1]. Nobutaka Kato, et al. Gene expression signatures and small-molecule compounds link a protein kinase to Plasmodium falciparum motility. Nat Chem Biol. 2008 Jun;4(6):347-56. [2]. Rajshekhar Y Gaji, et al. Expression of the essential Kinase PfCDPK1 from Plasmodium falciparum in Toxoplasma gondii facilitates the discovery of novel antimalarial drugs. Antimicrob Agents Chemother. 2014 May;58(5):2598-607.
AEG40826 (HGS1029) is the hydrochloride salt of a small-molecule inhibitor of IAP (Inhibitor of Apoptosis Protein) family proteins with potential antineoplastic activity. IAP inhibitor HGS1029 selectively inhibits the biological activity of IAP proteins, which may restore apoptotic signaling pathways; this agent may work synergistically with cytotoxic drugs to overcome tumor cell resistance to apoptosis. IAPs are overexpressed by many cancer cell types, suppressing apoptosis by binding and inhibiting active caspases-3, -7 and -9 via their BIR (baculoviral lAP repeat) domains.
Tazemetostat HCl is a potent, selective, and orally bioavailable small-molecule inhibitor of EZH2 enzymatic activity. EPZ-6438 induces apoptosis and differentiation specifically in SMARCB1-deleted MRT cells. Treatment of xenograft-bearing mice with EPZ-6438 leads to dose-dependent regression of MRTs with correlative diminution of intratumoral trimethylation levels of lysine 27 on histone H3, and prevention of tumor regrowth after dosing cessation. These data demonstrate the dependency of SMARCB1 mutant MRTs on EZH2 enzymatic activity and portend the utility of EZH2-targeted drugs for the treatment of these genetically defined cancers.