Development of Novel Isoindolone-Based Compounds against Trypanosoma brucei rhodesiense.

This study identified the isoindolone ring as a scaffold for novel agents against Trypanosoma brucei rhodesiense and explored the structure-activity relationships of various aromatic ring substitutions. The compounds were evaluated in an integrated in vitro screen. Eight compounds exhibited selective activity against T. b. rhodesiense (IC50 <2.2 µm) with no detectable side activity against T. cruzi and Leishmania infantum. Compound 20 showed low nanomolar potency against T. b. rhodesiense (IC50 =40 nm) and no toxicity against MRC-5 and PMM cell lines and may be regarded as a new lead template for agents against T. b. rhodesiense. The isoindolone-based compounds have the potential to progress into lead optimization in view of their highly selective in vitro potency, absence of cytotoxicity and acceptable metabolic stability. However, the solubility of the compounds represents a limiting factor that should be addressed to improve the physicochemical properties that are required to proceed further in the development of in vivo-active derivatives.

Synthesis and Bioactivities of Marine Pyran-Isoindolone Derivatives as Potential Antithrombotic Agents.

2,5-Bis-[8-(4,8-dimethyl-nona-3,7-dienyl)-5,7-dihydroxy-8-methyl-3-keto-1,2,7,8-teraahydro-6H-pyran[a]isoindol-2-yl]-pentanoic acid (FGFC1) is a marine pyran-isoindolone derivative isolated from a rare marine microorganism Stachybotrys longispora FG216, which showed moderate antithrombotic(fibrinolytic) activity. To further enhance its antithrombotic effect, a series of new FGFC1 derivatives (F1-F7) were synthesized via chemical modification at C-2 and C-2' phenol groups moieties and C-1″ carboxyl group. Their fibrinolytic activities in vitro were evaluated. Among the derivatives, F1-F4 and F6 showed significant fibrinolytic activities with EC50 of 59.7, 87.1, 66.6, 82.8, and 42.3 µM, respectively, via enhancement of urokinase activity. Notably, derivative F6 presented the most remarkable fibrinolytic activity (2.72-fold than that of FGFC1). Furthermore, the cytotoxicity of derivative F6 was tested as well as expression of Fas/Apo-1 and IL-1 on HeLa cells. The results showed that, compared to FGFC1, derivative F6 possessed moderate cytotoxicity and apoptotic effect on HeLa cells (statistical significance p > 0.1), making F6 a potential antithrombotic agent towards clinical application.

Vasorelaxant effects of benzodiazepines, non-benzodiazepine sedative-hypnotics, and tandospirone on isolated rat arteries.

Benzodiazepines (BDZs) and non-BDZ sedative-hypnotics are effective for the management of chronic insomnia; however, they are associated with adverse effects such as headache, dizziness, and palpitations. Furthermore, long-term use of these medications is associated with decreased blood pressure (BP) or depressed baroreflex function. Therefore, here, we assessed whether BDZs and non-BDZs cause vasorelaxation directly. Vasorelaxation in response to 22 BDZs, 2 non-BDZs, and tandospirone was determined by myograph methods using isolated Wistar rat thoracic aortas. All the drugs relaxed phenylephrine-contracted rat aortas in a concentration-dependent manner. Zolpidem and tandospirone caused over 80% relaxation at a concentration of 10 µM; diazepam, estazolam, etizolam, and tofisopam caused 60-70% relaxation; whereas 18 other BDZs (alprazolam, bromazepam, brotizolam, chlordiazepoxide, clobazam, clonazepam, clorazepate, ethyl loflazepate, flunitrazepam, flurazepam, lorazepam, lormetazepam, midazolam, nimetazepam, nitrazepam, oxazepam, temazepam, and triazolam) and zaleplon caused less than 50% relaxation. The relaxation was partially but significantly inhibited to the same extent by a nitric oxide (NO) synthase antagonist and after endothelium removal. Binding assay of gamma-aminobutyric acid type A receptors was performed using [3H]flunitrazepam. No correlation was observed between vasorelaxation at a concentration of 10 µM and the binding affinities for 23 drugs. The study demonstrated that zaleplon, zolpidem, tandospirone, and many BDZs cause vasorelaxation to different extents via endothelial NO-dependent and endothelium-independent pathways. In conclusion, the direct vasodilatory effects of these drugs may be involved in the mechanisms underlying their adverse effects. Additionally, the decreased BP observed in persons who take BDZs or non-BDZs may be partly due to direct vasodilation.

Phase 1 study of the HSP90 inhibitor onalespib in combination with AT7519, a pan-CDK inhibitor, in patients with advanced solid tumors.

PURPOSE: We conducted a phase 1 trial of the HSP90 inhibitor onalespib in combination with the CDK inhibitor AT7519, in patients with advanced solid tumors to determine the safety profile and maximally tolerated dose, pharmacokinetics, preliminary antitumor activity, and to assess the pharmacodynamic (PD) effects on HSP70 expression in patient-derived PBMCs and plasma. METHODS: This study followed a 3 + 3 trial design with 1 week of intravenous (IV) onalespib alone, followed by onalespib/AT7519 (IV) on days 1, 4, 8, and 11 of a 21-days cycle. PK and PD samples were collected at baseline, after onalespib alone, and following combination therapy. RESULTS: Twenty-eight patients were treated with the demonstration of downstream target engagement of HSP70 expression in plasma and PBMCs. The maximally tolerated dose was onalespib 80 mg/m2 IV + AT7519 21 mg/m2 IV. Most common drug-related adverse events included Grade 1/2 diarrhea (79%), fatigue (54%), mucositis (57%), nausea (46%), and vomiting (50%). Partial responses were seen in a palate adenocarcinoma and Sertoli-Leydig tumor; a colorectal and an endometrial cancer patient both remained on study for ten cycles with stable disease as the best response. There were no clinically relevant PK interactions for either drug. CONCLUSIONS: Combined onalespib and AT7519 is tolerable, though below monotherapy RP2D. Promising preliminary clinical activity was seen. Further benefit may be seen with the incorporation of molecular signature pre-selection. Further biomarker development will require the assessment of the on-target impact on relevant client proteins in tumor tissue.

Design and Synthesis of γ- and δ-Lactam M1 Positive Allosteric Modulators (PAMs): Convulsion and Cholinergic Toxicity of an M1-Selective PAM with Weak Agonist Activity.

Recent data demonstrated that activation of the muscarinic M1 receptor by a subtype-selective positive allosteric modulator (PAM) contributes to the gastrointestinal (GI) and cardiovascular (CV) cholinergic adverse events (AEs) previously attributed to M2 and M3 activation. These studies were conducted using PAMs that also exhibited allosteric agonist activity, leaving open the possibility that direct activation by allosteric agonism, rather than allosteric modulation, could be responsible for the adverse effects. This article describes the design and synthesis of lactam-derived M1 PAMs that address this hypothesis. The lead molecule from this series, compound 1 (PF-06827443), is a potent, low-clearance, orally bioavailable, and CNS-penetrant M1-selective PAM with minimal agonist activity. Compound 1 was tested in dose escalation studies in rats and dogs and was found to induce cholinergic AEs and convulsion at therapeutic indices similar to previous compounds with more agonist activity. These findings provide preliminary evidence that positive allosteric modulation of M1 is sufficient to elicit cholinergic AEs.

Embryonic vascular disruption adverse outcomes: Linking high throughput signaling signatures with functional consequences.

Embryonic vascular disruption is an important adverse outcome pathway (AOP) as chemical disruption of cardiovascular development induces broad prenatal defects. High throughput screening (HTS) assays aid AOP development although linking in vitro data to in vivo apical endpoints remains challenging. This study evaluated two anti-angiogenic agents, 5HPP-33 and TNP-470, across the ToxCastDB HTS assay platform and anchored the results to complex in vitro functional assays: the rat aortic explant assay (AEA), rat whole embryo culture (WEC), and the zebrafish embryotoxicity (ZET) assay. Both were identified as putative vascular disruptive compounds (pVDCs) in ToxCastDB and disrupted angiogenesis and embryogenesis in the functional assays. Differences were observed in potency and adverse effects: 5HPP-33 was embryolethal (WEC and ZET); TNP-470 produced caudal defects at lower concentrations. This study demonstrates how a tiered approach using HTS signatures and complex functional in vitro assays might be used to prioritize further in vivo developmental toxicity testing.

Synthesis, Antimicrobial, Antiquorum-Sensing, and Cytotoxic Activities of New Series of Isoindoline-1,3-dione, Pyrazolo[5,1-a]isoindole, and Pyridine Derivatives.

New series of isoindoline-1,3-diones 2-9, pyrazolo[5,1-a]isoindoles 10-14, and pyridines 16-18 were synthesized. Twenty of the synthesized compounds were screened for their antibacterial activity against S. aureus, B. cereus, and E. coli. Compound 5 was proved to be the most active member in this study, showing the highest antibacterial activity against the three selected microorganisms. The antifungal activity of these compounds was also tested against C. albicans and A. flavus 3375. Compounds 4, 5, 8, and 17a exhibited the best antifungal activity against A. flavus 3375. The same compounds were examined for their antiquorum-sensing activity against Ch. violacium ATCC 12472, whereas compound 5 displayed strong antiquorum-sensing activity. The in vitro cytotoxicity testing of compounds 4-9 and 17a against human normal lung fibroblast (W138) cell line revealed that compounds 4, 5, and 8 are the least cytotoxic analogs in this study. In vivo acute toxicity testing of compounds 4, 5, and 8 was performed. The DNA-binding affinity of compounds 4-9 and 17a was also tested and the obtained results showed that all tested compounds have moderate DNA-binding affinity.

Synthesis, in vitro protoporphyrinogen oxidase inhibition, and herbicidal activity of N-(benzothiazol-5-yl)hexahydro-1H-isoindole-1,3-diones and N-(benzothiazol-5-yl)hexahydro-1H-isoindol-1-ones.

Protoporphyrinogen oxidase (EC 1.3.3.4) is one of the most significant targets for a large family of herbicides. As part of our continuous efforts to search for novel protoporphyrinogen oxidase-inhibiting herbicides, N-(benzothiazol-5-yl)tetrahydroisoindole-1,3-dione was selected as a lead compound for structural optimization, leading to the syntheses of a series of novel N-(benzothiazol-5-yl)hexahydro-1H-isoindole-1,3-diones (1a-o) and N-(benzothiazol-5-yl)hexahydro-1H-isoindol-1-ones (2a-i). These newly prepared compounds were characterized by elemental analyses, (1) H NMR, and ESI-MS, and the structures of 1h and 2h were further confirmed by X-ray diffraction analyses. The bioassays indicated that some compounds displayed comparable or higher protoporphyrinogen oxidase inhibition activities in comparison with the commercial control. Very promising, compound 2a, ethyl 2-((6-fluoro-5-(4,5,6,7-tetrahydro-1-oxo-1H-isoindol-2(3H)-yl)benzo[d]thiazol-2-yl)-sulfanyl)acetate, was recognized as the most potent candidate with K(i) value of 0.0091 µm. Further greenhouse screening results demonstrated that some compounds exhibited good herbicidal activity against Chenopodium album at the dosage of 150 g/ha.

Antimalarial activity of imidazo[2,1-a]isoindol-5-ol derivatives and related compounds.

The synthesis of several series of imidazo[2,1-a]isoindol-5-ol derivatives and the results of their evaluation against Plasmodium falciparum are presented and discussed. The effects of electron-withdrawing or-donating substituents on different parts of the molecule, as well as those produced by the incorporation of an additional fused ring, were analyzed. Several compounds showed significant antimalarial activity in vitro with IC(50) values as low as 60 nM and a certain efficacy in vivo by reducing parasitemia in Plasmodium berghei mouse models.

Design of novel melatonin analogs for the reduction of intraocular pressure in normotensive rabbits.

Melatonin, the MT(2) melatonin receptor agonist IIK7 [N-butanoyl-2-(2-methoxy-6H-isoindolo[2,1-a]indol-11-yl)ethanamine], and the putative MT(3) melatonin receptor agonist 5-MCA-NAT [5-methoxycarbonylamino-N-acetyltryptamine] have previously been shown to reduce intraocular pressure (IOP) in ocular normotensive rabbits. To gain a better understanding of the structure-activity relationship of compounds that activate MT(2) and MT(3) receptors mediating reductions in IOP, novel melatonin analogs with rationally varied substitutions were synthesized and tested for their effects on IOP in ocular normotensive rabbits (n = 160). All synthesized melatonin analogs reduced IOP. The best-effect lowering IOP was obtained with the analogs INS48848 [methyl-1-methylene-2,3,4,9-tetrahydro-1H-carbazol-6-ylcarbamate], INS48862 [methyl-2-bromo-3-(2-ethanamidoethyl)-1H-indol-5-ylcarbamate], and INS48852 [(E)-N-(2-(5-methoxy-1H-indol-3-yl)ethyl)-3-phenylprop-2-enamide]. These compounds produced dose-dependent decreases in IOP that were maximal at 0.1 mM (total dose of 0.259 µg for INS48848, 0.354 µg for INS48862, and 0.320 µg for INS48852) and 1 mM (total dose of 2.59 µg for INS48848, 3.54 µg for INS48862, and 3.20 µg for INS48852), with maximal reductions of 36.0 ± 4.0, 24.0 ± 1.5, and 30.0 ± 1.5% for INS48848, INS48862, and INS48852, respectively. Studies using melatonin receptor antagonists (luzindole, prazosin, and DH97 [N-pentanoyl-2-benzyltryptamine]) indicated that INS48862 and INS48852 activate preferentially a MT(2) melatonin receptor and suggest that INS48848 may act mainly via a MT(3) receptor. The most effective compounds were also well tolerated in a battery of standard ocular surface irritation studies. The implication of these findings to the design of novel drugs to treat ocular hypertension is discussed.

Synthesis, cytotoxicity and pro-apoptosis of novel benzoisoindolin hydrazones as anticancer agents.

A series of benzoisoindolin hydrazones as analogues of natural lignan diphyllin were synthesized and the structures of these compounds were established by (1)H-NMR, (13)C-NMR, Mass and high resolution (HR)-MS. The compounds were evaluated for in vitro cytotoxicity against KB, A549 and HCT-116 cancer cell lines by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Compound 4 possessed the highest growth inhibitory effect. Significant apoptosis of HCT-116 cells treated with compound 4 was observed by Hoechst33342-propidium iodide (PI) and acridine orange (AO)-ethidium bromide (EB) staining assay. Western blot analysis disclosed that compound 4 induced apoptosis via the mitochondrial pathway accompanied by an increased expression of Bax and a decreased expression of Bcl-2.

Effect of binary combination of deltamethrin+MGK-264 on the levels of phospholipid and lipid peroxidation in the snail Lymnaea acuminata.

Effect of sublethal treatment of (40% and 60% of 48 h LC50) of deltamethrin+MGK on phospholipid level and rate of lipid peroxidation in nervous and foot tissue of Lymnaea acuminata were studied. Maximum reduction in phospholipid (24.10%) level and increase in rate of lipid peroxidation (586.8%) were observed in foot tissue of snail exposed to 60% of 48 h LC50 of deltamethrin+MGK 264 for 96 h. Alterations in the levels of phospholipids and rate of lipid peroxidation were time and concentration dependent. Use of MGK-264 with deltamethrin increases the toxicity of deltamethrin and their action on membrane phospholipids and rate of lipid peroxidation.

Novel water-soluble sedative-hypnotic agents: isoindolin-1-one derivatives.

We developed new intravenous sedative-hypnotic compounds with the isoindolin-1-one skeleton focusing on the water-soluble property and in vivo safety. We synthesized approximately 170 derivatives and evaluated their hypnotic effects by intravenous administration of the compounds to mice. A series of the 2-phenyl-3-[2-(4-methyl-1-piperazinyl)-2-oxoethyl]isoindolin-1-one analogs, 3(-), 5(-), 27(-), and 47(-) [JM-1232(-)], showed potent sedative-hypnotic activity with good water solubility and a wide safety margin. The hypnotic doses (HD50s) of these 4 compounds when administered to mice were 2.35, 1.90, 2.17, and 3.12 mg/kg, respectively, and the lethal doses (LD50s) were 88.67, 64.69, >120, and >120 mg/kg, respectively. The therapeutic indexes (LD50/HD50) were 37.73, 34.05, >55.30, and >38.46, respectively. Among these compound, 47(-) [JM-1232(-)] is being considered as the most potential candidate for clinical trials in humans.