A Novel AMPK Inhibitor Sensitizes Pancreatic Cancer Cells to Ferroptosis Induction.

Cancer cells must develop strategies to adapt to the dynamically changing stresses caused by intrinsic or extrinsic processes, or therapeutic agents. Metabolic adaptability is crucial to mitigate such challenges. Considering metabolism as a central node of adaptability, it is focused on an energy sensor, the AMP-activated protein kinase (AMPK). In a subtype of pancreatic ductal adenocarcinoma (PDAC) elevated AMPK expression and phosphorylation is identified. Using drug repurposing that combined screening experiments and chemoproteomic affinity profiling, it is identified and characterized PF-3758309, initially developed as an inhibitor of PAK4, as an AMPK inhibitor. PF-3758309 shows activity in pre-clinical PDAC models, including primary patient-derived organoids. Genetic loss-of-function experiments showed that AMPK limits the induction of ferroptosis, and consequently, PF-3758309 treatment restores the sensitivity toward ferroptosis inducers. The work established a chemical scaffold for the development of specific AMPK-targeting compounds and deciphered the framework for the development of AMPK inhibitor-based combination therapies tailored for PDAC.

Pharmacological degradation of ATR induces antiproliferative DNA replication stress in leukemic cells.

Mammalian cells replicate ~ 3 × 109 base pairs per cell cycle. One of the key molecules that slows down the cell cycle and prevents excessive DNA damage upon DNA replication stress is the checkpoint kinase ataxia-telangiectasia-and-RAD3-related (ATR). Proteolysis-targeting-chimeras (PROTACs) are an innovative pharmacological invention to molecularly dissect, biologically understand, and therapeutically assess catalytic and non-catalytic functions of enzymes. This work defines the first-in-class ATR PROTAC, Abd110/Ramotac-1. It is derived from the ATR inhibitor VE-821 and recruits the E3 ubiquitin-ligase component cereblon to ATR. Abd110 eliminates ATR rapidly in human leukemic cells. This mechanism provokes DNA replication catastrophe and augments anti-leukemic effects of the clinically used ribonucleotide reductase-2 inhibitor hydroxyurea. Moreover, Abd110 is more effective than VE-821 against human primary leukemic cells but spares normal primary immune cells. CRISPR-Cas9 screens show that ATR is a dependency factor in 116 myeloid and lymphoid leukemia cells. Treatment of wild-type but not of cereblon knockout cells with Abd110 stalls their proliferation which verifies that ATR elimination is the primary mechanism of Abd110. Altogether, our findings demonstrate specific anti-leukemic effects of an ATR PROTAC.

Design, synthesis, and biological characterization of proteolysis targeting chimera (PROTACs) for the ataxia telangiectasia and RAD3-related (ATR) kinase.

The Ataxia telangiectasia and RAD3-related (ATR) kinase is a key regulator of DNA replication stress responses and DNA-damage checkpoints. Several potent and selective ATR inhibitors are reported and four of them are currently in clinical trials in combination with radio- or chemotherapy. Based on the idea of degrading target proteins rather than inhibiting them, we designed, synthesized and biologically characterized a library of ATR-targeted proteolysis targeting chimera (PROTACs). Among the synthesized compounds, the lenalidomide-based PROTAC 42i was the most promising. In pancreatic and cervix cancer cells cancer cells, it reduced ATR to 40 % of the levels in untreated cells. 42i selectively degraded ATR through the proteasome, dependent on the E3 ubiquitin ligase component cereblon, and without affecting the associated kinases ATM and DNA-PKcs. 42i may be a promising candidate for further optimization and biological characterization in various cancer cells.

A Novel Approach for the Availability and Ocular Delivery of Tenoxicam Potassium: Synthesis, Characterization, and In Vivo Application.

Tenoxicam (TX) is a non-steroidal anti-inflammatory agent that can be used to control pain in various ophthalmic lesions like cataracts, refractive surgery, and corneal abrasion. TX has a very slightly aqueous solubility of 0.072 mg/mL resulting in difficulty to be formulated in ophthalmic solutions. This study aims to improve TX solubility by converting it into its potassium salt to achieve a target of 10 mg/mL (1%w/v) concentration of TX in the desired aqueous medium for the formulation of aqueous ophthalmic solutions. The synthesized TX salt was characterized by different evaluation parameters such as solubility studies, 1H NMR, IR, and elemental analyses. Different TX potassium solutions were formulated at concentrations of 0.5% and 1% w/v using different viscosity-imparting agents. The prepared solutions were characterized for their physicochemical properties including visual inspection, pH, rheological, in vitro release, and kinetic behavior. Also, the formulations were biologically evaluated in vivo using male albino rabbits. The obtained results showed the successful synthesis of TX salt, as indicated by IR and NMR, and elemental analysis. The solubility study showed that the solubility of TX was improved hugely to 18 mg/mL (250-fold). In addition, the results showed that the prepared formulations showed acceptable physicochemical properties. The highest release rate was obtained with formula F1, which contains no viscosity-imparting agents. While as, the lowest release rate was obtained in the case of formula F9, composed of Pluronic F127 (12% w/v). The in vivo results showed that TX optimized ophthalmic solutions F8 and F9 inhibited the redness and edema in an extended or sustained manner.

Crystal structure and Hirshfeld surface analysis of ethyl (3E)-5-(4-fluoro-phen-yl)3-{[(4-meth-oxy-phen-yl)formamido]-imino}-7-methyl-2H,3H,5H-[1,3]thia-zolo[3,2-a]pyrimidine-6-carboxyl-ate 0.25-hydrate.

In the title compound, C24H23FN4O4S·0.25H2O, the di-hydro-pyrimidine ring is distinctly non-planar, with the flap C atom deviating by 0.297 (2) Šfrom the least-squares plane. In the crystal, zigzag chains are formed by N-H⋯N hydrogen bonds parallel to [010] and are connected into layers parallel to (100) by O-H⋯O, O-H⋯F, C-H⋯O, C-H⋯F and C-H⋯N hydrogen bonds. Additional C-H⋯O hydrogen bonds connect the layers into a three-dimensional network. A Hirshfeld surface analysis indicates that the most significant contributions to the crystal packing are from H⋯H (42.6%), O⋯H/H⋯O (16.8%) and C⋯H/H⋯C (15.5%) contacts.

Crystal structure and Hirshfeld surface analysis of ethyl (3E)-5-(4-chloro-phen-yl)-3-{[(4-chloro-phen-yl)formamido]-imino}-7-methyl-2H,3H,5H-[1,3]thia-zolo[3,2-a]pyrimidine-6-carboxyl-ate.

In the title mol-ecule, C23H20Cl2N4O3S, the thia-zole ring is planar while the pyrimidine unit fused to it adopts a screw-boat conformation. In the crystal, thick sheets parallel to the bc plane are formed by N-H⋯N, C-H⋯N and C-H⋯O hydrogen bonds together with π-π inter-actions between the formamido carbonyl groups and the thia-zole rings. Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from H⋯H (30.9%), Cl⋯H/H⋯Cl (20.7%), C⋯H/H⋯C (16.8%) and O⋯H/H⋯O (11.4%) inter-actions.

Design and synthesis of pyrimidine-5-carbonitrile hybrids as COX-2 inhibitors: Anti-inflammatory activity, ulcerogenic liability, histopathological and docking studies.

Two new series of 1,3,4-oxadiazole and coumarin derivatives based on pyrimidine-5-carbonitrile scaffold have been synthesized and evaluated for their COX-1/COX-2 inhibitory activity. Compounds 10c, 10e, 10h-j, 14e-f, 14i and 16 were found to be the most potent and selective inhibitors of COX-2 (IC50 0.041-0.081 µM, SI 139.74-321.95). Eight compounds were further investigated for their in vivo anti-inflammatory activity. The most active derivatives 10c, 10j and 14e displayed superior in vivo anti-inflammatory activity (% edema inhibition 39.3-48.3, 1 h; 58.4-60.5, 2 h; 70.8-83.2, 3 h; 78.9-89.5, 4 h) to the reference drug celecoxib (% edema inhibition 38.0, 1 h; 48.8, 2 h; 58.4, 3 h; 65.4, 4 h). These derivatives were also tested for their ulcerogenic liability, compound 10j showed better safety profile with reference to celecoxib while 10c and 14e exhibited mild lesions. Molecular docking studies of 10c, 10j, and 14e in the COX-2 active site revealed similar orientation and binding interactions as selective COX-2 inhibitors with a higher liability to access the selectivity side pocket.

Design, synthesis and anticancer activity of new monastrol analogues bearing 1,3,4-oxadiazole moiety.

A series of dihydropyrimidine (DHPM) derivatives bearing 1,3,4-oxadiazole moiety was designed and synthesized as monastrol analogues. The new compounds were screened for their cytotoxic activity toward 60 cancer cell lines according to NCI (USA) protocol. Seven compounds were further examined against the most sensitive cell lines, leukemia HL-60(TB) and MOLT-4. The most active compounds were 9m against HL-60(TB) (IC50 = 56 nM) and 9n against MOLT-4 (IC50 = 80 nM), more potent than monastrol (IC50 = 147 and 215 nM, respectively). Cell cycle analysis of HL-60(TB) cells treated with 9m and MOLT-4 cells treated with 9n showed cell cycle arrest at G2/M phase and pro-apoptotic activity as indicated by annexin V-FITC staining.