Furo[3′,2′:3,4]naphtho[1,2-d]imidazole derivatives as potential inhibitors of inflammatory factors in sepsis

Cyclocondensation of 2-(α-Diazoacyl)-2H-azirines with Amidines in Diazo Synthesis of Functionalized Naphtho[1,2-d]imidazoles

A diazo approach toward functionalized naphtho[1,2-d]imidazole derivatives has been developed. It involved a new reaction of arylamidines with 2-(α-diazoacyl)-2H-azirines giving 5-aryl-4-(α-diazoacyl)-1H-imidazoles under mild conditions in good yields. The mechanism of annulation of azirines with amidines is discussed based on DFT calculations. The reaction proceeds in an unusual manner by cleavage of the azirine C-C bond, allowing for the transfer of the aryl substituent from the arylamidine to the proper position of the key intermediate of naphtho[1,2-d]imidazole synthesis. Under thermolysis conditions, 5-aryl-4-(α-diazoacyl)-1H-imidazoles undergo Wolff rearrangement followed by the selective 6π-cyclization of transient ketene to form 3H-naphtho[1,2-d]imidazoles bearing various substituents in the positions 2,3,4,5,7,8,9. Additionally, variation of the substituents at position 5 of naphtho[1,2-d]imidazoles is possible through the formation of triflates and subsequent cross-coupling reactions. One more heterocyclic pharmacophoric skeleton, 3H-furo[3',2':3,4]naphtho[1,2-d]imidazole, was easily constructed from methyl 5-hydroxy-3H-naphtho[1,2-d]imidazole-4-carboxylates in a one-pot mode using O-alkylation with phenacyl bromides followed by base-induced intramolecular acyl substitution at room temperature with high yields.

One-pot domino syntheses of 3-alkyl-3-N-substituted aminobenzofuran-2(3H)-ones based on alkali-promoted Michael addition and lactonization

In this paper, a novel cascade reaction of caesium carbonate-promoted Michael addition and lactonization for the one-pot synthesis of 3-alkyl-3-N-substituted aminobenzofuran-2(3H)-one derivatives has been established based on the screening of the alkaline reagents and optimization of reaction conditions, in which the N-substituted (ortho-hydroxy)aryl glycine esters were used as the Michael donors to react with different α, β-unsaturated carbonyl compounds. In the case of using the asymmetric starting material, the epimers could be successfully separated by conventional chromatography. In addition, plausible mechanisms were suggested and the absolute configuration of the epimer was analysed. All the chemical structures of unreported benzofuran-2(3H)-one derivatives were characterized by 1H nuclear magnetic resonance (NMR), 13C NMR, IR and high-resolution mass spectrometry (HRMS).

Crystal structure of S-2-(1-(5-methylpyridin-2-ylamino)octyl)-3-hydroxynaphthalene-1,4-dione, C24H28N2O3

[C24H28N2O3], monoclinic, P121/n, a = 12.8878(5) Å, b = 27.5641(11) Å, c = 13.0517(6) Å, β = 111.908(2)∘, V = 4301.7(3) Å3, Z = 4, Rgt (F) = 0.0576, wRref (F 2) = 0.1749, T = 296(2) K.

An Easy Access to Furan-Fused Polyheterocyclic Systems

Nitrostilbenes characterized by two different or differently substituted aryl moieties can be obtained from the initial ring-opening of 3-nitrobenzo[b]thiophene with amines. Such versatile building blocks couple the well-recognized double electrophilic reactivity of the nitrovinyl moiety (addition to the double bond, followed by, e.g., intramolecular replacement of the nitro group) with the possibility to exploit a conjugated system of double bonds within an electrocyclization process. Herein, nitrostilbenes are reacted with different aromatic enols provided by a double (carbon and oxygen) nucleophilicity, leading to novel, interesting naphthodihydrofurans. From these, as a viable application, aromatization and electrocyclization lead in turn to valuable polycondensed, fully aromatic O-heterocycles.

2-Benzyllawsone protects against polymicrobial sepsis and vascular hyporeactivity in swiss albino mice

BACKGROUND

Novel naphthoquinone, 2-benzyllawsone (LT-9) was evaluated against vascular hyporeactivity and sepsis in cecal ligation and puncture (CLP) model in mice in view of its preliminary antibacterial and anti-inflammatory properties and to explore whether pretreatment with the molecule could restore vascular tone and contractile response to norepinephrine.

METHODS

Evaluation of LT-9 against vascular hyporeactivity, hypotension, and sepsis-related inflammation and infection was carried out in the CLP model in Swiss albino mice and aortic smooth muscle cells in vitro.

RESULTS

LT-9 showed potent reversal of the vascular hyporeactivity in CLP mice aorta. The increased contraction response to norepinephrine in CLP mouse aorta by LT-9 was mediated by opening of L-type voltage-dependent calcium channels (VDCC) verified by ex vivo experiment where LT-9 enhanced contraction response to CaCl₂ in the aorta while abolishing the contraction response of known VDCC opener Bay K8644. LT-9 in aortic smooth muscle cells showed Fluo-4 mediated increase in calcium fluorescence. Oral administration of LT-9 at 50 and 100 mg kg^-1 day^-1 for 15 days significantly enhanced the mean survival time, improved hemodynamic and Electrocardiogram (ECG) profile, and aortic tissue reactivity in CLP mice. Further, LT-9 significantly reversed the perturbation of the expression profile of inflammatory cytokines, reduced the splenic microbial load, and was well tolerated in oral toxicity.

CONCLUSIONS

LT-9 showed potent biological activity against sepsis and was found to be well tolerated in the toxicity study in Swiss albino mice and showed promise for the benzyllawsone class of molecules against sepsis for the development of novel pharmacophore.

Synthetic Naphthofuranquinone Derivatives Are Effective in Eliminating Drug-Resistant Candida albicans in Hyphal, Biofilm, and Intracellular Forms: An Application for Skin-Infection Treatment

Candida albicans is the most common cause of fungal infection. The emergence of drug resistance leads to the need for novel antifungal agents. We aimed to design naphthofuranquinone analogs to treat drug-resistant C. albicans for topical application on cutaneous candidiasis. The time-killing response, agar diffusion, and live/dead assay of the antifungal activity were estimated against 5-fluorocytosine (5-FC)- or fluconazole-resistant strains. A total of 14 naphthofuranquinones were compared for their antifungal potency. The lead compounds with hydroxyimino (TCH-1140) or O-acetyl oxime (TCH-1142) moieties were the most active agents identified, showing a minimum inhibitory concentration (MIC) of 1.5 and 1.2 μM, respectively. Both compounds were superior to 5-FC and fluconazole for killing planktonic fungi. Naphthofuranquinones efficiently diminished the microbes inside and outside the biofilm. TCH-1140 and TCH-1142 were delivered into C. albicans-infected keratinocytes to eradicate intracellular fungi. The compounds did not reduce the C. albicans burden inside the macrophages, but the naphthofuranquinones promoted the transition of fungi from the virulent hypha form to the yeast form. In the in vivo skin mycosis mouse model, topically applied 5-FC and TCH-1140 reduced the C. albicans load from 1.5 × 10⁶ to 5.4 × 10⁵ and 1.4 × 10⁵ CFU, respectively. The infected abscess diameter was significantly decreased by TCH-1140 (3-4 mm) as compared to the control (8 mm). The disintegrated skin-barrier function induced by the fungi was recovered to the baseline by the compound. The data support the potential of TCH-1140 as a topical agent for treating drug-resistant C. albicans infection without causing skin irritation.

Inducible nitric oxide synthase inhibitors: A comprehensive update

Inducible nitric oxide synthase (iNOS), which is expressed in response to bacterial/proinflammatory stimuli, generates nitric oxide (NO) that provides cytoprotection. Overexpression of iNOS increases the levels of NO, and this increased NO level is implicated in pathophysiology of complex multifactorial diseases like Parkinson's disease, Alzheimer's disease, multiple sclerosis, rheumatoid arthritis, and inflammatory bowel disease. Selective inhibition of iNOS is an effective approach in treatment of such complex diseases. l-Arginine, being a substrate for iNOS, is the natural lead to develop iNOS inhibitors. More than 200 research reports on development of nitric oxide synthase inhibitors by different research groups across the globe have appeared in literature so far. The first review on iNOS, in 2002, discussed the iNOS inhibitors under two classes that is, amino acid and non-amino acid derivatives. Other review articles discussing specific chemical classes of iNOS inhibitors also appeared during last decade. In the present review, all reports on both natural and synthetic iNOS inhibitors, published 2002 onwards, are studied, classified, and discussed to provide comprehensive information on iNOS inhibitors. The synthetic inhibitors are broadly classified into two categories that is, arginine and non-arginine analogs. The latter are further classified into amidines, five- or six-membered heterocyclics, fused cyclics, steroidal type, and chalcones analogs. Structures of the most/significantly potent compounds from each report are provided to know the functional groups important for incurring iNOS inhibitory activity and selectivity. This review is aimed to provide a comprehensive view to the medicinal chemists for rational designing of novel and potent iNOS inhibitors.

Liposomal Avicequinone-B formulations: Aqueous solubility, physicochemical properties and apoptotic effects on cutaneous squamous cell carcinoma cells

BACKGROUND

Avicequinone-B (Naphtho[2,3-b]furan-4,9-dione) is a furanonaphthoquinone derivative. It is a hydrophobic compound with poor aqueous solubility, which may restrict its potential pharmaceutical and biomedical applications.

PURPOSE

We synthesized different liposomal formulations of Avicequinone-B, and measured their particle size, aqueous solubility, and physicochemical properties. In addition, we investigated the anticancer activity of liposomal Avicequinone-B in human cutaneous squamous cell carcinoma (SCC) cells.

METHODS

Liposomal Avicequinone-B formulations were synthesized using the thin-film hydration method. Drug yield, encapsulation efficiency and aqueous solubility were determined by high performance liquid chromatography. Particle size and polydispersity index were measured by submicron particle size analyzer, and ultrastructural morphology was visualized by transmission electron microscopy. Thermal transitions were determined by differential scanning calorimetry. Anti-skin cancer activity was determined in HSC-1 cells (human cutaneous SCC cell line) using the MTS cytotoxicity assay, apoptosis was assessed by caspase-3/7 activity assay, mitochondrial membrane potential was determined by JC-10 assay, and signal transduction pathways were evaluated by Western blot analysis.

RESULTS

Liposomal Avicequinone-B formulations showed adequate yield and high encapsulation efficiency. These liposomal formulations produced small, uniformly sized nanoparticles, and greatly increased the aqueous solubility of Avicequinone-B. Differential scanning calorimetry showed loss of thermal phase transitions. In addition, liposomal Avicequinone-B showed significant cytotoxic effect on HSC-1 cells, through reduction of mitochondrial membrane potential, increased cytosolic cytochrome-c level, increased cleaved caspase 8 level, and induction of apoptosis. This was mediated through activation of ERK, p38 and JNK signaling pathways.

CONCLUSION

Liposomal Avicequinone-B demonstrated improved aqueous solubility and physicochemical characteristics, and induced apoptosis in cutaneous SCC cells. Therefore, liposomal Avicequinone-B may have potential uses as a topical anti-skin cancer drug formulation in the future.

Discovery of 2-Substituted 3-Arylquinoline Derivatives as Potential Anti-Inflammatory Agents Through Inhibition of LPS-Induced Inflammatory Responses in Macrophages

We describe herein the preparation of certain 2-substituted 3-arylquinoline derivatives and the evaluation of their anti-inflammatory effects in LPS-activated murine J774A.1 macrophage cells. Among these newly synthesized 2-substituted 3-arylquinoline derivatives, 2-(4-methoxy- benzoyl)-3-(3,4,5-trimethoxyphenyl)quinoline (18a) and 2-(4-fluorobenzoyl)-3-(3,4,5-trimethoxy- phenyl)quinoline (18b) are two of the most active compounds which can inhibit the production of NO at non-cytotoxic concentrations. Our results have also indicated that compounds 18a and 18b significantly decrease the secretion of pro-inflammatory cytokines (TNF-á and IL-6), inhibit the expression of iNOS, suppress the phosphorylation of MAPKs, and attenuate the activity of NF-êB by LPS-activated macrophages. Through molecular docking analysis, we found that 18b could fit into the middle of the TNF-á dimer and form hydrophobic interactions with Leu55, Leu57 chain A and B, Tyr59, Val123 chain B and D, Ile 155. These results suggest that both 18a and 18b are potential lead compounds in inhibiting LPS-induced inflammatory responses. Further structural optimization to discover novel anti-inflammatory agents is ongoing.

Phytochemical naphtho[1,2-b] furan-4,5‑dione induced topoisomerase II-mediated DNA damage response in human non-small-cell lung cancer

BACKGROUND

Phytochemical naphtho[1,2-b] furan-4,5‑dione (NFD) presenting in Avicennia marina exert anti-cancer effects, but little is known regarding about DNA damage-mediated apoptosis in non-small-cell lung carcinoma (NSCLC).

PURPOSE

To examine whether NFD-induced apoptosis of NSCLC cells is correlated with the induction of DNA damage, and to investigate its underlying mechanism.

STUDY DESIGN

The anti-proliferative effects of NFD were assessed by MTS Assay Kit FACS assay, and in vivo nude mice xenograft assay. The DNA damage related proteins, the Bcl-2 family and pro-apoptotic factors were examined by immunofluorescence assay, q-PCR, and western blotting. The activity of NF-κB p65 in nuclear extracts was detected using a colorimetric DNA-binding ELISA assay. The inhibitory activity of topoisomerase II (TOPO II) was evaluated by molecular docking and TOPO II catalytic assay.

RESULTS

NFD exerted selective cytotoxicity against NSCLC H1299, H1437 and A549 cells rather than normal lung-embryonated cells MRC-5. Remarkably, we found that NFD activated the hull marker and modulator of DNA damage repairs such as γ-H2AX, ATM, ATR, CHK1, and CHK2 probably caused by the accumulation of intracellular reactive oxygen species (ROS) and inhibition of TOPO II activity. Furthermore, the suppression of transcription factor NF-κB by NFD resulted in significantly decreased levels of pro-survival proteins including Bcl-2 family Bcl-2, Bcl-xL and Mcl-1 and the endogenous inhibitors of apoptosis XIAP and survivin in H1299 cells. Moreover, the nude mice xenograft assay further validated the suppression of H1299 growth by NFD, which is the first report for evaluating the anti-cancer effect of NFD in vivo.

CONCLUSION

These findings provide a novel mechanism indicating the inhibition of TOPO II activity and NF-κB signaling by NFD, leading to DNA damage and apoptosis of NSCLC tumor cells.

A ZnI2-catalyzed regioselective cascade 1,4-conjugate addition/5-exo-dig annulation pathway for one-pot access to heterobiaryl frameworks

Facile access to π-extended heterobiaryl compounds via a non-cross-coupling strategy has been achieved.

Synthesis and Biological Evaluation of Thalidomide Derivatives as Potential Anti-Psoriasis Agents

Several thalidomide derivatives were synthesized and evaluated for their anti-inflammatory activity. Introduction of the benzyl group to the parent thalidomide is unfavorable in which 2-(1-benzyl-2,6-dioxopiperidin-3-yl)isoindoline-1,3-dione (4a) was inactivated. However, the inhibitory activities on TNF-α and IL-6 expression in HaCaT cells were improved by the substitution of a chloro- or methoxy- group at the phenyl position of 4a. The IL-6 inhibitory activity decreased in an order of 5c (69.44%) > 4c (48.73%) > 6c (3.19%) indicating the 3-substituted derivative is more active than the 4-substituted counterpart, which in turn is more active than the 2-substituted counterpart. Among them, 2-[1-(3-chlorobenzyl)-2,6-dioxopiperidin-3-yl]isoindoline-1,3-dione (5c) was found to inhibit TNF-α and IL-6 expression in HaCaT cells with a higher potency than thalidomide and no significant cell cytotoxicity was detected at 10 μM. In psoriasis, Compound 5c reduced IL-6, IL-8, IL-1β and IL-24 in imiquimod-stimulated models. Our results indicated that compound 5c is a potential lead of novel anti-psoriasis agents. Structural optimization of compound 5c and its in vivo assay are ongoing.

Organocatalytic Aza-Friedel-Crafts/Lactonization Domino Reaction of Naphthols and Phenols with 2-Acetamidoacrylate to Naphtho- and Benzofuranones Bearing a Quaternary Center at the C3 Position

N-Acetyl ketimine generated from methyl 2-acetamidoacrylate was explored to develop an unprecedented domino aza-Friedel-Crafts/lactonization reaction with naphthols and phenols (including 5-hydroxyindoles). This novel method requires a catalyst loading of only 5 mol % of a phosphoric acid catalyst and provides a new series of 3-NHAc-naphtho- and benzofuranone derivatives bearing tetra-substituted stereogenic centers in moderate-to-good yields. The enantioselective variant using BINOL-derived phosphoric acids was also explored with 1-naphthol, providing the desired product with moderate enantioselectivities (up to 99:1 following recrystallization).

Napabucasin and Related Heterocycle-Fused Naphthoquinones as STAT3 Inhibitors with Antiproliferative Activity against Cancer Cells

Napabucasin (6) and its angularly anellated isomer (7), for which the synthesis is described, together with related plant-derived naphthoquinones, were evaluated in vitro against human breast cancer (MDA-MB-231) and chronic myelogenous leukemia (K562) cells. As observed for β-lapachone (3), the active naphthoquinones all induced apoptosis in a cell-cycle-independent fashion. In contrast to the pyran-fused β-lapachone (3), however, the most potent furan-fused naphthoquinones were able to redox cycle and generate superoxide in cell-based assays, which was independent of NAD(P)H:quinone oxido-reductase 1. In a homogeneous time-resolved fluorescence (HTRF) assays with MDA-MB-231 cells, both napabucasin (6) and isonapabucasin (7) were identified as targeting STAT3 phosphorylation. In addition, drug affinity responsive target stability assays were performed to validate a direct interaction of the naphthoquinones with STAT3. Isonapabucasin (7) turned out to be twice as potent against STAT3 as napabucasin (6) in the HTRF assay, with an EC₅₀ in the submicromolar range, which was in excellent agreement with the potency of both agents to inhibit the growth of MDA-MB-231 cells. Moreover, molecular docking experiments predicted different binding modes to the STAT3 SH2 domain for the linearly anellated napabucasin (6) and its angularly anellated isomer (7).

Discovery of Pyrazolo[4,3-c]quinolines Derivatives as Potential Anti-Inflammatory Agents through Inhibiting of NO Production

The synthesis and anti-inflammatory effects of certain pyrazolo[4,3-c]quinoline derivatives 2a–2r are described. The anti-inflammatory activities of these derivatives were evaluated by means of inhibiting nitric oxide (NO) production in lipopolysaccharide (LPS)-induced RAW 264.7 cells. Among them, 3-amino-4-(4-hydroxyphenylamino)-1H-pyrazolo[4,3-c]-quinoline (2i) and 4-(3-amino-1H-pyrazolo[4,3-c]quinolin-4-ylamino)benzoic acid (2m) exhibited significant inhibition of LPS-stimulated NO production with a potency approximately equal to that of the positive control, 1400 W. Important structure features were analyzed by quantitative structure–activity relationship (QSAR) analysis to give better insights into the structure determinants for predicting the inhibitory effects on the accumulation of nitric oxide for RAW 264.7 cells in response to LPS. In addition, our results indicated that their anti-inflammatory effects involve the inhibition of inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2) protein expression. Further studies on the structural optimization are ongoing.

An efficient synthesis of naphtho[2,1-b]furan-2(1H)-ones catalysed by Nafion-H supported on silica-coated super paramagnetic iron oxide nanoparticles

A one-pot procedure is descibed for the synthesis of naphtho[2,1- b]furan-2(1 H)-ones via a multicomponent reaction of aryl aldehydes, hippuric acid, acetic anhydride and β-naphthol in the presence of Nafion-H supported on silica-coated superparamagnetic iron oxide nanoparticles under microwave irradiation. The catalyst can be recovered easily and reused several times without significant loss of catalytic activity.

Discovery of Indeno[1,2-c]quinoline Derivatives as Potent Dual Antituberculosis and Anti-Inflammatory Agents

A series of indeno[1,2-c]quinoline derivatives were designed, synthesized and evaluated for their anti-tuberculosis (anti-TB) and anti-inflammatory activities. The minimum inhibitory concentration (MIC) of the newly synthesized compound was tested against Mycobacterium tuberculosis H₃₇R_V. Among the tested compounds, (E)-N′-[6-(4-hydroxypiperidin-1-yl)-11H-indeno[1,2-c]quinolin-11-ylidene]isonicotino-hydrazide (12), exhibited significant activities against the growth of M. tuberculosis (MIC values of 0.96 μg/mL) with a potency approximately equal to that of isoniazid (INH), an anti-TB drug. Important structure features were analyzed by quantitative structure–activity relationship (QSAR) analysis to give better insights into the structure determinants for predicting the anti-TB activity. The anti-inflammatory activity was induced by superoxide anion generation and neutrophil elastase (NE) release using the formyl-l-methionyl-l-leucyl-l-phenylalanine (fMLF)-activated human neutrophils method. Results indicated that compound 12 demonstrated a potent dual inhibitory effect on NE release and superoxide anion generation with IC₅₀ values of 1.76 and 1.72 μM, respectively. Our results indicated that compound 12 is a potential lead compound for the discovery of dual anti-TB and anti-inflammatory drug candidates. In addition, 6-[3-(hydroxymethyl)piperidin-1-yl]-9-methoxy-11H-indeno[1,2-c]quinolin-11-one (4g) showed a potent dual inhibitory effect on NE release and superoxide anion generation with IC₅₀ values of 0.46 and 0.68 μM, respectively, and is a potential lead compound for the discovery of anti-inflammatory drug candidates.

The deep eutectic melt of sorbitol and metformin hydrochloride: synthesis of 3-substituted 2-aminonaphtho[2,3-b]furan-4,9-diones and their photophysical properties

The low-melting deep-eutectic mixture of sorbitol and metformin HCl was successfully employed as a recyclable solvent for promoting the synthesis of benzofuroquinone dyes.

A Novel pseudo-Four-Component Domino Reaction for the Synthesis of Naphtho[2,1-b]furan-2(1H)-ones Using a Nanocatalyst

In this article, an original one-pot method is utilized to synthesize a variety of derivatives of naphtho[2,1-b]furan-2(1H)-one via a pseudo-four-component domino reaction of aryl aldehydes, acetic anhydride, hippuric acids, and 2-naphthols catalyzed by HSW@SPIONs. This reaction illustrates an array of attractive features including, with particular interest in this report, a convenient and unique process of creating and utilizing a powerful recyclable nanocatalyst.

Discovery of benzo[f]indole-4,9-dione derivatives as new types of anti-inflammatory agents

Certain benzo[f]indole-4,9-dione derivatives were synthesized and evaluated for their inhibitory effects on superoxide anion generation and neutrophil elastase (NE) release in formyl-l-methionyl-l-leucyl-l-phenylalanine (fMLF)-activated human neutrophils. Results indicated that (Z)-1-benzyl-4-(hydroxyimino)-1H-benzo[f]indol-9(4H)-one (10) showed a potent dual inhibitory effect on NE release and superoxide anion generation with IC50 value of 2.78 and 2.74 μM respectively. The action mechanisms of 10 in human neutrophils were further investigated. Our results showed that compound 10 did not alter fMLF-induced phosphorylation of Src (Src family Y416). Notably, phosphorylation of Akt (S473) and mobilization of [Ca2+]i caused by fMLF was inhibited by compound 10. Further structural optimization of 10 is ongoing.

Four-component reaction between naphthols, substituted β-nitrostyrenes, substituted benzaldehydes and ammonium acetate in water–PEG-400: an approach to construct polysubstituted naphthofuranamines

The diversity-oriented synthesis of naphtho[b]furans via a four-component reaction between naphthanols, substituted β-nitrostyrenes, substituted benzaldehydes and ammonium acetate has been developed.

Natural inhibitors of PI3K/AKT signaling in breast cancer: emphasis on newly-discovered molecular mechanisms of action

Epidermal growth factor receptor (EGFR) plays a critical role in the initiation and progression of a variety of human cancers, including breast cancer. An important signaling pathway downstream of EGFR is the PI3K/AKt pathway, which regulates cellular processes as diverse as cell growth, survival, proliferation and migration. Deregulated activity of this pathway may lead to uncontrolled cell growth, survival, migration and invasion, contributing to tumor formation. In this review, we evaluate natural compounds that, in vitro (breast cancer cell lines) and/or in vivo (animal model, clinical) studies, suppress breast cancer cells or tumors mainly by suppressing the PI3K/AKT signaling pathway. The effect of these compounds on cell cycle arrest, inhibition of cell migration and invasion, tumor angiogenesis and metastasis in breast cancer are discussed.

Furano-1,2-Naphthoquinone Inhibits Src and PI3K/Akt Signaling Pathways in Ca9-22 Human Oral Squamous Carcinoma Cells

Furano-1,2-naphthoquinone (FNQ), a biologically active component ofAvicennia marina, has been demonstrated to display anticancer activity. FNQ exerted cytotoxicity with the G2/M cell cycle arrest and apoptosis in Ca9-22 cells. FNQ-induced G2/M arrest was correlated with a marked decrease in the expression levels of cyclin A and cyclin B, and their activating partner cyclin-dependent kinases (CDK) 1 and 2 with concomitant induction of p27. FNQ-induced apoptosis was accompanied by Bax and Bad upregulation, and the downregulation of Bcl-2, Bcl-XL, Mcl-1, and X-linked inhibitor of apoptosis (XIAP), resulting in cytochrome C release and sequential activation of caspase-9 and caspase-3. Mechanistic studies showed that FNQ suppressed Src phosphorylation, PI3K, and Akt activation in Ca9-22 cells. Moreover, the Src inhibitor PP2 reduced the phosphorylation of Src and activation of PI3K/Akt, which was comparable with FNQ treatment. The combined treatment of FNQ with PP2 enhanced the cell cycle arrest and apoptosis and also led to the downregulation of Bcl-XL, Mcl-1, XIAP, cyclin A, cyclin B, CDK1, and CDK2 and upregulation of p27, Bax, and Bad. These findings suggest that FNQ-mediated cytotoxicity of Ca9-22 cells is related with the G2/M cell cycle arrest and apoptosis via inactivation of Src and PI3K/Akt-mediated signaling pathways.

The signaling mechanisms mediating the inhibitory effect of TCH-1116 on formyl peptide-stimulated superoxide anion generation in neutrophils

In fMLP (formyl-Met-Leu-Phe)-stimulated rat neutrophils, a mixture of regioisomers benzo[a]furo[2,3-c]phenazine-10-carboxylic acid and benzo[a]furo[2,3-c]phenazine-11-carboxylic acid (TCH-1116) inhibited O(2)(-) (superoxide anion) generation, which was not mediated by scavenging the generated O(2)(-) or by a cytotoxic effect on neutrophils. TCH-1116 had no effect on the arachidonic acid-induced NADPH oxidase activation in a cell-free system, whereas it effectively attenuated the phosphorylation of Ser residues in p47(phox) and the association between p47(phox) and p22(phox) in fMLP-stimulated neutrophils. The interaction of p47(phox) with PKC (protein kinase C) isoforms (α, βI, βII, δ and ζ) was attenuated by TCH-1116, whereas TCH-1116 did not affect the PKC isoforms membrane translocation, phosphorylation (Ser660) and kinase activity. TCH-1116 effectively attenuated the association between PKB/Akt (protein kinase B) and p47(phox), Akt phosphorylation (Thr308/Ser473) and kinase activities of Akt and human recombinant PDK (3-phosphoinositide-dependent kinase) 1, whereas it had no effect on recruitment of Akt, phospho-PDK1 (Ser241) and p110γ to membrane. Moreover, the interaction of p21-activated kinase (PAK) 1 with p47(phox) and the phosphorylation of PAK1 (Thr423 but not Ser144) were inhibited by TCH-1116, but without affecting the membrane recruitment of PAK1. The cellular cyclic AMP level was not changed by TCH-1116. Taken together, these results suggest that TCH-1116 inhibits fMLP-stimulated O(2)(-) generation in rat neutrophils through the blockade of PKC, Akt and PAK signaling pathways.

Synthesis of modified steroids as a novel class of non-ulcerogenic, anti-inflammatory and anti-nociceptive agents

The identification of compounds able to treat both pain and inflammation with limited side effects is one of the prominent goals in biomedical research. This study aimed at the synthesis of new modified steroids with structures justifying non-ulcerogenic, anti-inflammatory and anti-nociceptive activities. The steroid derivatives were synthesized via straightforward and efficient methods and their structures were established based on the analytical and spectral data. The in vivo anti-inflammatory, anti-nociceptive and anti-ulcerogenic activities of some of these compounds were studied. The newly synthesized compounds 8b, 19b, 24 and 31a showed anti-inflammatory, anti-nociceptive and anti-ulcerogenic activity with various intensities. Oedema was significantly reduced by either dose 25 or 50 mg/kg of all tested compounds at 3 and 4 h post-carrageenan. Compound 19b was the most effective in alleviating thermal pain. The analgesic activity of either dose of the compounds 8b, 24, 31a as well as the high dose 19b was significantly higher than that for indomethacin (IND). Gastric mucosal lesions caused in the rats by the administration of 96% EtOH and IND were inhibited by all tested compounds administered at (50 mg/kg) dose in the study.

Furano-1,2-naphthoquinone inhibits EGFR signaling associated with G2/M cell cycle arrest and apoptosis in A549 cells

Furano-1,2-naphthoquinone (FNQ), prepared from 2-hydroxy-1,4-naphthoquinone and chloroacetaldehyde in an efficient one-pot reaction, exhibits an anti-carcinogenic effect. FNQ exerted anti-proliferative activity with the G(2)/M cell cycle arrest and apoptosis in A549 cells. FNQ-induced G(2)/M arrest was correlated with a marked decrease in the expression levels of cyclin A and cyclin B, and their activating partner cyclin-dependent kinases (Cdk) 1 and 2 with concomitant induction of p53, p21, and p27. FNQ-induced apoptosis was accompanied with Bax up-regulation and the down-regulation of Bcl-2, X-linked inhibitor of apoptosis (XIAP), and survivin, resulting in cytochrome c release and sequential activation of caspase-9 and caspase-3. Western blot analysis revealed that FNQ suppressed EGFR phosphorylation and JAK2, STAT3, and STAT5 activation, but increased in activation of p38 MAPK and c-Jun NH2-terminal kinase (JNK) stress signal. The combined treatment of FNQ with AG1478 (a specific EGFR inhibitor) significantly enhanced the G(2)/M arrest and apoptosis, and also led to up-regulation in Bax, p53, p21, p27, release of mitochondrial cytochrome c, and down-regulation of Bcl-2, XIAP, survivin, cyclin A, cyclin B, Cdk1, and Cdk2 in A549 cells. These findings suggest that FNQ-mediated cytotoxicity of A549 cell related with the G(2)/M cell cycle arrest and apoptosis via inactivation of EGFR-mediated signaling pathway.

Naphtho[1,2-b]furan-4,5-dione induces apoptosis of oral squamous cell carcinoma: involvement of EGF receptor/PI3K/Akt signaling pathway

Naphtho[1,2-b]furan-4,5-dione (NFD), prepared from 2-hydroxy-1,4-naphthoquinone and chloroacetaldehyde in an efficient one-pot reaction, exerts an anti-tumor effect. This study was performed to elucidate whether the epidermal growth factor (EGF) receptor and phosphatidylinositol-3-kinase (PI3K) signaling pathways are involved in NFD-induced apoptosis of oral squamous cell carcinoma (OSCC). Immunoblot showed that NFD suppressed the phosphorylation of EGF receptor and activation of PI3K/Akt, downstream molecules of EGF receptor signaling pathway, in Ca9-22 cells. The levels of downstream targets of Akt, including phospho-glycogen synthase kinase-3beta (p-GSK-3beta), GSK-3beta, forkhead transcription factor (FKHR), and cyclin D1, were also reduced after NFD treatment. Moreover, inactivation of nuclear factor-kappaB (NF kappaB), modulation of I kappa K beta and I kappaB alpha, up-regulation of Bad, and down-regulation of anti-apoptotic proteins including phospho-Bad, Bcl-X(L), myeloid cell leukemia-1(Mcl-1), and XIAP were found in NFD-treated cells. In addition, NFD treatment disrupted mitochondrial membrane potential (Delta Psi m), resulted in release of cytochrome c, and activation of both caspases-9 and caspase-3. Taken together, these results indicate that NFD induces apoptosis in Ca9-22 cells via inactivation of the EGF receptor-mediated survival pathway.

Naphtho[1,2-b]furan-4,5-dione disrupts Janus kinase-2 and induces apoptosis in breast cancer MDA-MB-231 cells

Naphtho[1,2-b]furan-4,5-dione (NFD), prepared from 2-hydroxy-1,4-naphthoquinone and chloroacetaldehyde in an efficient one-pot reaction, exhibits an anti-carcinogenic effect. NFD-induced apoptosis in MDA-MB-231 cells, as indicated by the accumulation of sub-G1 population, externalization of phosphatidylserine, loss of mitochondrial membrane potential (DeltaPsim) with subsequent release of cytochrome c, and activation of both capase-9 and caspase-3. This correlated with up-regulation in Bax and Bad, and down-regulation of various anti-apoptotic proteins, including Bcl-2, Bcl-X(L), Mcl-1, and survivin in NFD-treated cells. In the analysis of signal transduction pathway, NFD suppressed the phosphorylation of JAK2 in MDA-MB-231 cells without altering the expression of JAK2 protein. Activation of STAT3, Src, and PI3K/Akt were also inhibited by NFD. Moreover, the JAK2 inhibitor AG490 blocked JAK2, STAT3, Src, PI3K, and Akt activation, whereas both Src inhibitor PP2 and PI3K inhibitor wortmannin did not affect JAK2 activation. This suggests that STAT3, Src, and PI3K/Akt are downstream molecules of the JAK2 signaling pathway. AG490 treatment also mimics the cytotoxic effects of NFD. Taken together, these results indicate that NFD disrupts JAK2 pathway and induces apoptosis in MDA-MB-231 cells.

Naphtho[1,2-b]furan-4,5-dione inactivates EGFR and PI3K/Akt signaling pathways in human lung adenocarcinoma A549 cells

AIMS

Naphtho[1,2-b]furan-4,5-dione (NFD), prepared from 2-hydroxy-1,4-naphthoquinone and chloroacetaldehyde in an efficient one-pot reaction, exhibits an anti-carcinogenic effect. This study was performed to elucidate whether EGFR and PI3K signaling pathways are involved in NFD-induced apoptosis of human lung adenocarcinoma A549 cells.

MAIN METHODS

The effect of NFD on cell viability and apoptosis was measured by the MTT assay and flow cytometry. The phosphorylation levels of EGFR and its regulatory molecules by NFD treatment were studied by immunoblots.

KEY FINDINGS

Immunoblot showed that NFD inhibited EGFR phosphorylation and the activation of PI3K/Akt, downstream molecules of EGFR pathway, in A549 cells. The levels of downstream targets of Akt, including phospho-glycogen synthase kinase-3beta (p-GSK-3beta), GSK-3beta, forkhead transcription factor (FKHR), and cyclin D1, were also reduced after NFD treatment. Moreover, inactivation of nuclear factor-kappaB (NFkappaB), modulation of IkappaKalpha/beta and IkappaBalpha, up-regulation of Bad and Bax, and down-regulation of anti-apoptotic proteins including phospho-Bad, Bcl-2, survivin, and XIAP were also found in NFD-treated cells. In addition, NFD treatment disrupted mitochondrial membrane potential (DeltaPsim) and resulted in release of mitochondrial cytochrome c and activation of both caspases-9 and caspase-3.

SIGNIFICANCE

These findings indicate that EGFR and PI3K/Akt signaling pathways play important roles in NFD-induced apoptosis of A549 cells.