Benzofuran and Benzo[b]thiophene-2-carboxamide Derivatives as Modulators of Amyloid Beta (Aß42) Aggregation.

A group of N-phenylbenzofuran-2-carboxamide and N-phenylbenzo[b]thiophene-2-carboxamide derivatives were designed and synthesized as a novel class of Aß42 aggregation modulators. In the thioflavin-T based fluorescence aggregation kinetics study, compounds 4a, 4b, 5a and 5b possessing a methoxyphenol pharmacophore were able to demonstrate concentration dependent inhibition of Aß42 aggregation with maximum inhibition of 54% observed for compound 4b. In contrast, incorporation of a 4-methoxyphenyl ring in compounds 4d and 5d led to a significant increase in Aß42 fibrillogenesis demonstrating their ability to accelerate Aß42 aggregation. Compound 4d exhibited 2.7-fold increase in Aß42 fibrillogenesis when tested at the maximum concentration of 25 µM. These results were further confirmed by electron microscopy studies which demonstrates the ability of compounds 4a, 4b, 4d, 5a, 5b and 5d to modulate Aß42 fibrillogenesis. Compounds 5a and 5b provided significant neuroprotection to mouse hippocampal neuronal HT22 cells against Aß42-induced cytotoxicity. Molecular docking studies suggest that the orientation of the bicyclic aromatic rings (either benzofuran or benzo[b]thiophene) plays a major role in moderating their ability to either inhibit or accelerate Aß42 aggregation. Our findings support the application of these novel derivatives as pharmacological tools to study the mechanisms of Aß42 aggregation.

Glutamine Metabolism Mediates Sensitivity to Respiratory Complex II Inhibition in Acute Myeloid Leukemia.

Acute myeloid leukemia (AML) is a hematologic malignancy metabolically dependent on oxidative phosphorylation and mitochondrial electron transport chain (ETC) activity. AML cells are distinct from their normal hematopoietic counterparts by this metabolic reprogramming, which presents targets for new selective therapies. Here, metabolic changes in AML cells after ETC impairment are investigated. Genetic knockdown of the ETC complex II (CII) chaperone protein SDHAF1 (succinate dehydrogenase assembly factor 1) suppressed CII activity and delayed AML cell growth in vitro and in vivo. As a result, a novel small molecule that directly binds to the ubiquinone binding site of CII and inhibits its activity was identified. Pharmacologic inhibition of CII induced selective death of AML cells while sparing normal hematopoietic progenitors. Through stable isotope tracing, results show that genetic or pharmacologic inhibition of CII truncates the tricarboxylic acid cycle (TCA) and leads to anaplerotic glutamine metabolism to reestablish the truncated cycle. The inhibition of CII showed divergent fates, as AML cells lacked the metabolic plasticity to adequately utilize glutamine metabolism, resulting in preferential depletion of key TCA metabolites and death; normal cells were unaffected. These findings provide insight into the metabolic mechanisms that underlie AML's selective inhibition of CII. IMPLICATIONS: This work highlights the effects of direct CII inhibition in mediating selective AML cell death and provides insights into glutamine anaplerosis as a metabolic adaptation that can be therapeutically targeted.

The effects of heat and freeze-thaw cycling on naloxone stability.

PURPOSE: The availability of take home naloxone (THN) was increased for Canadians in 2016, including access to kits via pharmacies. Unlike typical over-the-counter (OTC) and prescription drugs, THN kits may be stored in non-standard conditions, including in vehicles, backpacks, and out of doors. To evaluate whether these non-standard storage conditions affect stability, we investigated the impact of heat and freeze-thaw cycling on naloxone hydrochloride stability. METHODS: To assess the effect of heat, naloxone hydrochloride ampoules were exposed to 80 °C in a temperature-controlled oven for 8 h followed by 16 h at room temperature. To assess the effect of freeze-thaw cycles, naloxone hydrochloride ampoules were exposed to - 20 °C for 16 h followed by 8 h at 4 °C. The impact of these conditions on naloxone hydrochloride stability was evaluated each day for 1 week and after 2 and 4 weeks. The concentration of remaining naloxone hydrochloride was quantified using high-performance liquid chromatography (HPLC). Naloxone hydrochloride ampoules stored at room temperature served as the experimental control. RESULTS: Naloxone hydrochloride ampoules exhibit no changes in drug concentration following exposure to heat or freeze-thaw cycles for up to 28 days compared to ampoules maintained at room temperature (as indicated in the product monograph). CONCLUSIONS: Naloxone hydrochloride remains chemically stable following exposure to heat or freeze-thaw cycles after 28 days. If THN kits are stored in non-standard conditions (for up to 28 days) the active naloxone is likely to remain stable. Despite this, pharmacists should continue to emphasize the importance of appropriate storage of THN kits to ensure optimal efficacy should naloxone administration be required in an emergency situation.