Design and synthesis of 3,4-dihydro-2H-benzo[h]chromene derivatives as potential NF-κB inhibitors

Induction of Paraptotic Cell Death in Breast Cancer Cells by a Novel Pyrazolo[3,4-h]quinoline Derivative through ROS Production and Endoplasmic Reticulum Stress

Chemotherapy has been a standard intervention for a variety of cancers to impede tumor growth, mainly by inducing apoptosis. However, development of resistance to this regimen has led to a growing interest and demand for drugs targeting alternative cell death modes, such as paraptosis. Here, we designed and synthesized a novel derivative of a pyrazolo[3,4-h]quinoline scaffold (YRL1091), evaluated its cytotoxic effect, and elucidated the underlying molecular mechanisms of cell death in MDA-MB-231 and MCF-7 breast cancer (BC) cells. We found that YRL1091 induced cytotoxicity in these cells with numerous cytoplasmic vacuoles, one of the distinct characteristics of paraptosis. YRL1091-treated BC cells displayed several other distinguishing features of paraptosis, excluding autophagy or apoptosis. Briefly, YRL1091-induced cell death was associated with upregulation of microtubule-associated protein 1 light chain 3B, downregulation of multifunctional adapter protein Alix, and activation of extracellular signal-regulated kinase 1/2 and c-Jun N-terminal kinase. Furthermore, the production of reactive oxygen species (ROS) and newly synthesized proteins were also observed, subsequently causing ubiquitinated protein accumulation and endoplasmic reticulum (ER) stress. Collectively, these results indicate that YRL1091 induces paraptosis in BC cells through ROS generation and ER stress. Therefore, YRL1091 can serve as a potential candidate for the development of a novel anticancer drug triggering paraptosis, which may provide benefit for the treatment of cancers resistant to conventional chemotherapy.

Discovery of novel aminosaccharide-based sulfonamide derivatives as potential carbonic anhydrase II inhibitors

In this paper, a new class of novel sulfonamides incorporating aminosaccharide tails were designed and synthesized based on the sugar-tail approach. Then, all the novel compounds were evaluated for their inhibitory activities against three carbonic anhydrase (CA, EC 4.2.1.1) isoenzymes (hCA I, hCA II and hCA IX). Interestingly, effective inhibition of these three CA isoforms were observed, especially the glaucoma associated isoform hCA II. It is worth noting that these glycoconjugated sulfonamide derivatives also showed better CA inhibitory effects compared to the initial segment carzenide. Among them, compound 8d was the most effective inhibitor with IC₅₀ of 60 nM against hCA II. Subsequent physicochemical properties studies showed that all compounds have good water solubility and neutral pH values in solutions. And these important physicochemical properties make target compounds acquire obvious advantages in the preparation of topical and nonirritating antiglaucoma drugs. Moreover, the target compounds showed lower corneal cytotoxicity than acetazolamide (AAZ) and good metabolic stability in vitro. In addition, molecular docking studies confirmed the interactions between aminosaccharide fragment and hydrophilic subpocket of hCA II active site were crucial for the enhanced CA inhibitory activity. Taken together, these results suggested 8d would be a promising lead compound for the development of topical antiglaucoma CAIs.

Design, synthesis, and biological evaluation of potent 1,2,3,4-tetrahydroisoquinoline derivatives as anticancer agents targeting NF-κB signaling pathway

The multifunctional transcription factor, nuclear factor-κB (NF-κB), is broadly involved in multiple human diseases, such as cancer and chronic inflammation, through abnormal modulations of the NF-κB signaling cascades. In patients with several types of cancer diseases, NF-κB is excessively activated, which could result in the stimulation of proliferation and/or suppression of apoptosis. Herein, we present a new series of 1,2,3,4-tetrahydroisoquinoline derivatives with good anticancer activities against various human cancer cell lines, which are rationally designed based on our novel NF-κB inhibitors. The SAR studies demonstrated that compound 5d with a methoxy group at the R₃ position exhibits the most anti-proliferative activity with GI₅₀ values, ranging 1.591 to 2.281 μM. Similar to KL-1156, the compound 5d (HSR1304) blocked NF-κB nuclear translocation step in LPS-stimulated MDA-MB-231 cells, probably leading to cytotoxic potency against tumor cells. Together with known potent NF-κB inhibitors containing diverse core heterocyclic moieties, the 1,2,3,4-tetrahydroisoquinoline derivatives can provide structural diversity, enhancing a potential for the development of a novel class of anticancer drugs.

2H/4H-Chromenes-A Versatile Biologically Attractive Scaffold

2H/4H-chromene (2H/4H-ch) is an important class of heterocyclic compounds with versatile biological profiles, a simple structure, and mild adverse effects. Researchers discovered several routes for the synthesis of a variety of 2H/4H-ch analogs that exhibited unusual activities by multiple mechanisms. The direct assessment of activities with the parent 2H/4H-ch derivative enables an orderly analysis of the structure-activity relationship (SAR) among the series. Additionally, 2H/4H-ch have numerous exciting biological activities, such as anticancer, anticonvulsant, antimicrobial, anticholinesterase, antituberculosis, and antidiabetic activities. This review is consequently an endeavor to highlight the diverse synthetic strategies, synthetic mechanism, various biological profiles, and SARs regarding the bioactive heterocycle, 2H/4H-ch. The presented scaffold work compiled in this article will be helpful to the scientific community for designing and developing potent leads of 2H/4H-ch analogs for their promising biological activities.

Synthesis of N-arylindazole-3-carboxamide and N-benzoylindazole derivatives and their evaluation against α-MSH-stimulated melanogenesis

We have designed and synthesized twenty-six N-arylindazole-3-carboxamide (3a-p) and N-benzoylindazole (6a-j) derivatives to discover with excellent inhibition activities of α-MSH-stimulated melanogenesis. In the bio evaluation studies of these compounds, we discovered eighteen compounds, out of twenty-six exhibited more potent inhibition than the positive control arbutin. From the SAR studies, we identified 3k and 6g as lead compounds which displayed almost 5 and 9 times more potent inhibition of α-MSH-stimulated melanogenesis respectively than the reference arbutin. It is also evident the presence of electron withdrawing group at para position (R³) for the compounds (3a-p) and presence of +M group at ortho position (R⁵) for the compounds (6a-j) were crucial for their excellent inhibition activities of α-MSH-stimulated melanogenesis.

Development of 13H-benzo[f]chromeno[4,3-b][1,7]naphthyridines and their salts as potent cytotoxic agents and topoisomerase I/IIα inhibitors

A novel series of 35 angularly fused pentacyclic 13H-benzo[f]chromeno[4,3-b][1,7]naphthyridines and 13H-benzo[f]chromeno[4,3-b][1,7]naphthyridin-5-ium chlorides were designed and synthesized. Their cytotoxic activities were investigated against six human cancer cell lines (NCIH23, HCT15, NUGC-3, ACHN, PC-3, and MDA-MB-231). Among all screened compounds; 28, 30, 34, 35, 46, 48, 52, and 53 compounds exhibited potent cytotoxic activities against all tested human cancer cell lines. Further, these potent lead cytotoxic agents were evaluated against human Topoisomerase I and IIα inhibition. Among them, the compound 48 exhibited dual Topoisomerase I and IIα inhibition especially at 20 μM concentrations the compound 48 exhibited 1.25 times more potent Topoisomerase IIα inhibitory activity (38.3%) than the reference drug etoposide (30.6%). The compound 52 also exhibited excellent (88.4%) topoisomerase I inhibition than the reference drug camptothecin (66.7%) at 100 μM concentrations. Molecular docking studies of the compounds 48 and 52 with topo I discovered that they both intercalated into the DNA single-strand cleavage site where the compound 48 have van der Waals interactions with residues Arg364, Pro431, and Asn722 whilst the compound 52 have with Arg364, Thr718, and Asn722 residues. Both the compounds 48 and 52 have π-π stacking interactions with the stacked DNA bases. The docking studies of the compound 48 with topo IIα explored that it was bound to the topo IIα DNA cleavage site where etoposide was situated. The benzo[f]chromeno[4,3-b][1,7]naphthyridine ring of the compound 48 was stacked between the DNA bases of the cleavage site with π-π stacking interactions and there were no hydrogen bond interactions with topo IIα.

Isolation of intermediates in the synthesis of new 3,4-dihydro-2H-chromeno[2,3-d]pyrimidines

Reaction ofN-alkyl-2-imino-2H-chromene-3-carboxamides with dimethyl acetylenedicarboxylate (DMAD) in the presence of sodium carbonate as catalyst in refluxing ethanol gave new tricyclic products identified as methyl 3-alkyl-2-(2-methoxy-2-oxoethyl)-4-oxo-3,4-dihydro-2H-chromeno[2,3-d]pyrimidine-2-carboxylates. In the absence of sodium carbonate, dimethyl 2-((E)-3-(alkylcarbamoyl)-2H-chromen-2-ylideneamino)fumarates were isolated as intermediates. These intermediates could be successfully converted to the same new tricyclic products by heating in ethanol containing sodium carbonate. All new synthetic compounds were characterized on the basis of their FT-IR,1H and13C NMR spectra, and microanalytical data. To identify the correct stereoisomer of the intermediates, in one case a 2D nuclear Overhauser effect (2D-NOESY) spectrum together with density functional theory (DFT) calculation at the B3LYP/6-311+G(d,p) level of theory was used.

Antioxidant and Neuroprotective Effects of N-((3,4-Dihydro-2H-benzo[h]chromen-2-yl)methyl)-4-methoxyaniline in Primary Cultured Rat Cortical Cells: Involvement of ERK-CREB Signaling

Excitotoxicity and oxidative stress play vital roles in the development of neurodegenerative disorders including Alzheimer's disease (AD). In the present study, we investigated the effect of N-((3,4-dihydro-2H-benzo[h]chromen-2-yl)methyl)-4-methoxyaniline (BL-M) on excitotoxic neuronal cell damage in primary cultured rat cortical cells, and compared to that of memantine, a non-competitive N-methyl-d-aspartate (NMDA) receptor antagonist clinically used to treat AD. We found that BL-M inhibited glutamate- or N-methyl-d-aspartate (NMDA)-induced excitotoxic cell damage. The IC50 value of BL-M against NMDA toxicity was comparable to that of memantine. BL-M potently inhibited intracellular reactive oxygen species generated by glutamate or NMDA. Additionally, it inhibited the formation of 1,1-diphenyl-2-picryl-hydrazyl radicals in vitro and lipid peroxidation in rat brain homogenates. In contrast, memantine showed minimal or negligible antioxidant activity. Western blotting and immunocytochemical analyses showed that BL-M, not memantine, increased the ERK1/2 phosphorylation and subsequent phosphorylation of cAMP response element-binding protein (CREB). The inhibition of NMDA toxicity by BL-M was dramatically reversed by U0126, a well-known MEK inhibitor, suggesting that ERK1/2-mediated CREB phosphorylation is required for the neuroprotective action. Collectively, in this study, we demonstrated the neuroprotective effect of a newly synthesized chromene derivative BL-M and its underlying action mechanism(s). In contrast to memantine, BL-M exhibited marked antioxidant activity. Furthermore, it enhanced the ERK-mediated phosphorylation of CREB, which plays a crucial neuroprotective role. Our findings suggest that BL-M may be beneficial for AD and other neurodegenerative disorders associated with excitotoxicity as well as oxidative stress.

Dual Inhibition of NOX2 and Receptor Tyrosine Kinase by BJ-1301 Enhances Anticancer Therapy Efficacy via Suppression of Autocrine-Stimulatory Factors in Lung Cancer

NADPH oxidase-derived reactive oxygen species (ROS) potentiate receptor tyrosine kinase (RTK) signaling, resulting in enhanced angiogenesis and tumor growth. In this study, we report that BJ-1301, a hybrid of pyridinol and alpha-tocopherol, exerts anticancer effects by dual inhibition of NADPH oxidase and RTK activities in endothelial and lung cancer cells. BJ-1301 suppresses ROS production by blocking translocation of NADPH oxidase cytosolic subunits to the cell membrane, thereby inhibiting activation. The potency of RTK inhibition by BJ-1301 was lower than that of sunitinib (a multi-RTK inhibitor), but the inhibition of downstream signaling pathways (e.g., ROS generation) and subsequent biological changes (e.g., NOX2 induction) by BJ-1301 was superior. Consistently, BJ-1301 inhibited cisplatin-resistant lung cancer cell proliferation more than sunitinib did. In xenograft chick or mouse tumor models, BJ-1301 inhibited lung tumor growth, to an extent greater than that of sunitinib or cisplatin. Treatments with BJ-1301 induced regression of tumor growth, potentially due to downregulation of autocrine-stimulatory ligands for RTKs, such as TGFα and stem cell factor, in tumor tissues. Taken together, the current study demonstrates that BJ-1301 is a promising anticancer drug for the treatment of lung cancer. Mol Cancer Ther; 16(10); 2144-56. ©2017 AACR.

Development of Novel 1,2,3,4-Tetrahydroquinoline Scaffolds as Potent NF-κB Inhibitors and Cytotoxic Agents

1,2,3,4-Tetrahydroquinolines have been identified as the most potent inhibitors of LPS-induced NF-κB transcriptional activity. To discover new molecules of this class with excellent activities, we designed and synthesized a series of novel derivatives of 1,2,3,4-tetrahydroquinolines (4a-g, 5a-h, 6a-h, and 7a-h) and bioevaluated their in vitro activity against human cancer cell lines (NCI-H23, ACHN, MDA-MB-231, PC-3, NUGC-3, and HCT 15). Among all synthesized scaffolds, 6g exhibited the most potent inhibition (53 times that of a reference compound) of LPS-induced NF-κB transcriptional activity and the most potent cytotoxicity against all evaluated human cancer cell lines.

Crystal structure of 1-(8-methoxy-2H-chromen-3-yl)ethanone

In the structure of the title compound, C12H12O3, the dihydropyran ring is fused with the benzene ring. The dihydropyran ring is in a half-chair conformation, with the ring O and methylene C atoms positioned 1.367 (3) and 1.504 (4) Å, respectively, on either side of the mean plane formed by the other four atoms. The methoxy group is coplanar with the benzene ring to which it is connected [Cb—Cb—Om—Cmtorsion angle = −0.2 (4)°; b = benzene and m = methoxy], and similarly the aldehyde is coplanar with respect to the double bond of the dihydropyran ring [Cdh—Cdh—Ca—Oa= −178.1 (3)°; dh = dihydropyran and a = aldehyde]. In the crystal, molecules are linked by weak methyl–methoxy C—H...O hydrogen bonds into supramolecular chains along thea-axis direction.