4-{3-[(Pyridin-4-ylmethyl)amino]-[1,2,4]triazolo[4,3-b][1,2,4]triazin-6-yl}phenol: An improved anticancer agent in hepatocellular carcinoma and a selective MDR1/MRP modulator.

Hepatocellular carcinoma is the most common type of primary liver cancer. However, multidrug resistance (MDR) is a major obstacle to the effective chemotherapy of cancer cells. This report documents the rational design, synthesis, and biological evaluation of a novel series of triazolotriazines substituted with CH2NH-linked pyridine for use as dual c-Met/MDR inhibitors. Compound 12g with IC50 of 3.06 µM on HepG2 cells showed more potency than crizotinib (IC50 = 5.15 µM) in the MTT assay. In addition, 12g inhibited c-Met kinase at a low micromolar level (IC50 = 0.052 µM). 12g significantly inhibited P-gp and MRP1/2 efflux pumps in both cancerous HepG2 and BxPC3 cells starting from the lower concentrations of 3 and 0.3 µM, respectively. 12g did not inhibit MDR1 and MRP1/2 in noncancerous H69 cholangiocytes up to the concentration of 30 and 60 µM, respectively. Current results highlighted that cancerous cells were more susceptible to the effect of 12g than normal cells, in which the inhibition occurred only at the highest concentrations, suggesting a further interest in 12g as a selective anticancer agent. Overall, 12g, as a dual c-Met and P-gp/MRP inhibitor, is a promising lead compound for developing a new generation of anticancer agents.

Phenelzine protects against acetaminophen induced apoptosis in HepG2 cells.

Acetaminophen (APAP) overdosing is the most common cause of drug-induced liver failure. Despite extensive study, N-acetylcysteine is currently the only antidote utilized for treatment. The purpose of this study was to evaluate the effect and mechanisms of phenelzine, an FDA-approved antidepressant, on APAP-induced toxicity in HepG2 cells. The human liver hepatocellular cell line HepG2 was used to investigate APAP-induced cytotoxicity. The protective effects of phenelzine were determined by examining the cell viability, combination index calculation, Caspase 3/7 activation, Cytochrome c release, H2O2 levels, NO levels, GSH activity, PERK protein levels, and pathway enrichment analysis. Elevated H2O2 production and decreased glutathione (GSH) levels were indicators of APAP-induced oxidative stress. The combination index of 2.04 indicated that phenelzine had an antagonistic effect on APAP-induced toxicity. When compared to APAP alone, phenelzine treatment considerably reduced caspase 3/7 activation, cytochrome c release, and H2O2 generation. However, phenelzine had minimal effect on NO and GSH levels and did not alleviate ER stress. Pathway enrichment analysis revealed a potential connection between APAP toxicity and phenelzine metabolism. These findings suggested that phenelzine's protective effect against APAP-induced cytotoxicity could be attributed to the drug's capacity to reduce APAP-mediated apoptotic signaling.

Combined effect of fulvestrant and low dose BPA: comparative implications on EMT, apoptosis, and TGF-ß1 signaling in HepG2 cells.

Bisphenol A (BPA) is an endocrine-disrupting chemical utilized in the manufacture of food packaging, dental materials, medical devices, children's toys, and baby products. Numerous studies have indicated the role of BPA in the etiology of many diseases such as diabetes, cardiovascular diseases, obesity, cancer, and chemotherapeutic resistance. However, the effects of BPA- chemotherapeutic combination remain to be investigated in different cell lines. Here, we demonstrate that low dose BPA and fulvestrant (estrogen receptor antagonist) combination synergistically decrease proliferation, promote cell migration and mesenchymal transition, switching from E-cadherin to N-cadherin expression Hepg2 cells. Moreover, we determined that low dose BPA may evoke susceptibility to apoptosis in HepG2 cells. The mechanism underlying these effects has been identified as increased TGF-ß1 signaling. Our results provide an experimental basis for evaluating the potential health risks of low-dose BPA for fulvestrant therapy in hepatocytes.

Hybridization-based design of novel anticholinesterase indanone-carbamates for Alzheimer's disease: Synthesis, biological evaluation, and docking studies.

Inspired by the structures of donepezil and rivastigmine, a novel series of indanone-carbamate hybrids was synthesized using the pharmacophore hybridization-based design strategy, and their biological activities toward acetylcholinesterase (AChE) and butyrylcholinesterase were evaluated. Among the synthesized compounds, 4d and 4b showed the highest AChE inhibitory activities with IC50 values in the micromolar range (compound 4d: IC50 = 3.04 µM; compound 4b: IC50 = 4.64 µM). Moreover, the results of the Aß1-40 aggregation assay revealed that compound 4b is a potent Aß1-40 aggregation inhibitor. The kinetics of AChE enzymatic activity in the presence of 4b was investigated, and the results were indicative of a reversible partial noncompetitive type of inhibition. A molecular docking study was conducted to determine the possible allosteric binding mode of 4b with the enzyme. The allosteric nature of AChE inhibition by these compounds provides the opportunity for the design of subtype-selective enzyme inhibitors. The presented indanone-carbamate scaffold can be structurally modified and optimized through medicinal chemistry-based approaches for designing novel multitargeted anti-Alzheimer agents.

A review: Biologically active 3,4-heterocycle-fused coumarins.

The combination of heterocycles offers a new opportunity to create novel multicyclic compounds having improved biological activity. Coumarins are ubiquitous natural heterocycle widely adopted in the design of various biologically active compounds. Fusing different heterocycles with coumarin ring is one of the interesting approaches to generating novel hybrid molecules having highlighted biological activities. In the efforts to develop heterocyclic-fused coumarins, a wide range of 3,4-heterocycle-fused coumarins have been introduced bearing outstanding biological activity. The effect of heterocycles annulation at 3,4-positions of coumarin ring on the biological activity of the target structures were discussed. This review focuses on the important progress of 3,4-heterocycle-fused coumarins providing better insight for medicinal chemists on the design and preparation of biologically active heterocycle-fused coumarins with a significant therapeutic effect in the future.

Synthesis, molecular docking, and biological evaluation of novel 2-pyrazoline derivatives as multifunctional agents for the treatment of Alzheimer's disease.

A novel series of 2-pyrazoline derivatives were designed, synthesized, and evaluated for cholinesterase (ChE) inhibitory, Aß anti-aggregating and neuroprotective activities. Among these, 3d, 3e, 3g, and 3h were established as the most potent and selective BChE inhibitors (IC50 = 0.5-3.9 µM), while 3f presented dual inhibitory activity against BChE and AChE (IC50 = 6.0 and 6.5 µM, respectively). Kinetic analyses revealed that 3g is a partial noncompetitive inhibitor of BChE (Ki = 2.22 µM), while 3f exerts competitive inhibition on AChE (Ki = 0.63 µM). The active compounds were subsequently screened for further assessments. 3f, 3g and 3h reduced Aß1-42 aggregation levels significantly (72.6, 83.4 and 63.4%, respectively). In addition, 3f demonstrated outstanding neuroprotective effects against Aß1-42-induced and H2O2-induced cell toxicity (95.6 and 93.6%, respectively). Molecular docking studies were performed with 3g and 3f to investigate binding interactions inside the active sites of BChE and AChE. Compounds 3g and 3f might have the multifunctional potential for use against Alzheimer's disease.

3-Aryl Coumarin Derivatives Bearing Aminoalkoxy Moiety as Multi-Target-Directed Ligands against Alzheimer's Disease.

Two series of novel coumarin derivatives, substituted at 3 and 7 positions with aminoalkoxy groups, are synthesized, characterized, and screened. The effect of amine substituents and the length of cross-linker are investigated in acetyl- and butyrylcholinesterase (AChE and BuChE) inhibition. Target compounds show moderate to potent inhibitory activities against AChE and BuChE. 3-(3,4-Dichlorophenyl)-7-[4-(diethylamino)butoxy]-2H-chromen-2-one (4y) is identified as the most potent compound against AChE (IC50 =0.27 µm). Kinetic and molecular modeling studies affirmed that compound 4y works in a mixed-type way and interacts simultaneously with the catalytic active site (CAS) and peripheral anionic site (PAS) of AChE. In addition, compound 4y blocks ß-amyloid (Aß) self-aggregation with a ratio of 44.11 % at 100 µm and significantly protects PC12 cells from H2 O2 -damage in a dose-dependent manner.

Low-dose bisphenol A induces RIPK1-mediated necroptosis in SH-SY5Y cells: Effects on TNF-α and acetylcholinesterase.

Bisphenol A (BPA) is an endocrine disruptor chemical, which is commonly used in everyday products. Adverse effects of its exposure are reported even at picomolar doses. Effects of picomolar and nanomolar concentrations of BPA on cytotoxicity, nitric oxide (NO) levels, acetylcholinesterase (AChE) gene expression and activity, and tumor necrosis factor-α (TNF-α) and caspase-8 levels were determined in SH-SY5Y cells. The current study reveals that low-dose BPA treatment induced cytotoxicity, NO, and caspase-8 levels in SH-SY5Y cells. We also evaluated the mechanism underlying BPA-induced cell death. Ours is the first report that receptor-interacting serine/threonine-protein kinase 1-mediated necroptosis is induced by nanomolar BPA treatment in SH-SY5Y cells. This effect is mediated by altered AChE and decreased TNF-α levels, which result in an apoptosis-necroptosis switch. Moreover, our study reveals that BPA is an activator of AChE.

Novel multi-targeted agents for Alzheimer's disease: Synthesis, biological evaluation, and molecular modeling of novel 2-[4-(4-substitutedpiperazin-1-yl)phenyl]benzimidazoles.

The present study describes the synthesis, pharmacological evaluation (BChE/AChE inhibition, Aß antiaggregation, and neuroprotective effects), and molecular modeling studies of novel 2-[4-(4-substitutedpiperazin-1-yl)phenyl]benzimidazole derivatives. The alkyl-substituted derivatives exhibited selective inhibition on BChE with varying efficiency. Compounds 3b and 3d were found to be the most potent inhibitors of BChE with IC50 values of 5.18 and 5.22µM, respectively. The kinetic studies revealed that 3b is a partial non-competitive BChE inhibitor. Molecular modeling studies also showed that the alkyl-substituted derivatives were able to reach the catalytic anionic site of the BChE. The compounds with an inhibitory effect on BChE were subsequently screened for their Aß antiaggregating and neuroprotective activities. Compounds 3a and 3b exerted a potential neuroprotective effect against H2O2 and Aß-induced cytotoxicity in SH-SY5Y cells. Collectively, 3b was found as the most promising compound for the development of multi-target directed ligands against Alzheimer's disease.

Design, synthesis and in vitro study of 5,6-diaryl-1,2,4-triazine-3-ylthioacetate derivatives as COX-2 and ß-amyloid aggregation inhibitors.

In order to find novel cyclooxygenase (COX)-2 inhibitors for treating inflammatory-based diseases such as Alzheimer's disease (AD), an ethyl carboxylate side chain was added to 5-(4-chlorophenyl)-6-(4-(methylsulfonyl)phenyl)-3-(methylthio)-1,2,4-triazine (lead compound II) to maintain residual inhibition of COX-1 through interacting with Arg120. A preliminary molecular docking study on both the COX-1/COX-2 active sites truly confirmed our hypothesis. Accordingly, a series of ethyl 5,6-diaryl-1,2,4-triazine-3-ylthioacetate derivatives were synthesized and their chemical structures were confirmed by NMR, IR and MS spectra. Further in vitro COX-1/COX-2 evaluations revealed that compound 6c (COX-2 IC50 = 10.1 µM, COX-1 IC50 = 88.8 µM) is the most selective COX-2 inhibitor while maintaining residual inhibition of COX-1. In order to evaluate their potential use against AD, an in vitro evaluation of ß-amyloid fibril formation was performed. The results indicated that the prototype compounds 6 are effective ß-amyloid destabilizing agents while compound 6c could inhibit 94% of the ß-amyloid fibril formation after 48 h. Finally, the in silico assessment results of their blood-brain barrier permeability were satisfactory.

1,2-Diaryl-2-hydroxyiminoethanones as dual COX-1 and ß-amyloid aggregation inhibitors: biological evaluation and in silico study.

To find out new agents for treating inflammatory-involved diseases such as Alzheimer's disease, a series of 1,2-diaryl-2-hydroxyiminoethanones containing vicinal diaryl pharmacophore of COX inhibitors were tested by a set of in vitro, in vivo, and computational studies. The in vivo study of compounds indicated their prominent anti-inflammatory ability at the doses of 10 and 20 mg/kg comparable to celecoxib (10 mg/kg). Further in vitro COX-1/COX-2 evaluations revealed that 4-methoxy derivative 3 had a high selective COX-1 inhibitory activity (COX-1, IC50=0.12 µm, SI>833). To evaluate their potential use against Alzheimer's disease, in vitro evaluation of ß-amyloid fibril formation using Aß(1-40) and Aß(1-42) peptides was performed. The evaluation of their antiaggregation ability gave impressive results and comparable to rifampicin and indomethacin. Conformational study of compound 3 and subsequent docking of its restrained analogs on both active sites of COX-1 and COX-2 could provide a proof of its COX-1 selectivity as well as molecular dynamic simulation could elucidate and give more insight into the amyloid disaggregation mechanisms leading to rational design of inhibitors.