Inhibition of fos-jun-DNA complex formation by dihydroguaiaretic acid and in vitro cytotoxic effects on cancer cells

Cytotoxicity Activity of Some meso-Dihydroguaiaretic Acid Derivatives and Mode of Action of the Most Active Compound

The aim of this study was to screen sixteen meso-1 semi-synthetic derivatives bearing ether, esther, carbamate, phosphate or aminoether functional groups against five cancer cell lines: MCF-7 (breast), A549 (lung), HepG2 (liver), HeLa (cervix), and DU145 (prostate) at 25 μM using the MTT assay. Results from the screening showed that two derivatives had the lowest percentage of cell viability at 25 μM, the aminoether derivative meso-11 and the esther derivative meso-20 against A549 (44.15±0.78 %) and MCF-7 (41.60±0.92 %), respectively. Then, it was determined the IC50 value of each compound against their most sensitive cancer cell line. Results showed that aminoether derivative meso-11 showed potent cytotoxicity against A549 (IC50 =17.11±2.11 μM), whereas it resulted more cytotoxic against the LL-47 lung normal cell line (IC50 =9.49±1.19 μM) having a Selective Index (SI) of 0.55. On the other hand, the esther derivative meso-20 exhibited potent activity against MCF-7 (IC50 =18.20±1.98 μM), whereas it displayed moderate cytotoxicity against the MCF-10 breast normal cell line (IC50 =41.22±2.17 μM) with a SI of 2.2. Finally, studies on the mechanism of action of meso-20 indicated disruption of MCF-7 plasma membrane in vitro and the AMPK activation in silico.

Understanding apoptotic induction by Sargentodoxa cuneata-Patrinia villosa herb pair via PI3K/AKT/mTOR signalling in colorectal cancer cells using network pharmacology and cellular studies

ETHNOPHARMACOLOGICAL RELEVANCE

Sargentodoxa cuneata (Sargentodoxa cuneata (Oliv.) Rehder & E.H.Wilson, DXT)-Patrinia villosa(Patrinia villosa (Thunb.) Dufr, BJC) constitutes a commonly employed herb pair in Chinese medicine for colorectal cancer (CRC) treatment. Modern pharmacological investigations have revealed the anticancer activities of both Sargentodoxa cuneata and Patrinia villosa. Nevertheless, comprehensive studies are required to discern the specific antitumor active ingredients and mechanism of action when these two herbs are used in combination.

AIM OF THE STUDY

Through the integration of network pharmacology, molecular docking techniques, experimental assays, and bioinformatics analysis, our study aims to forecast the active ingredients, potential targets, and molecular mechanisms underlying the therapeutic efficacy of this herb pair against CRC.

MATERIALS AND METHODS

Plant names (1, Sargentodoxa cuneata (Oliv.) Rehder & E.H.Wilson; 2, Patrinia villosa (Thunb.) Dufr.) have been verified through WorldFloraOnline (www.worldFloraonline.org) and MPNs (http://mpns.kew.org). The Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP) were utilized for screening the active ingredients of the herb pair. The PharmMapper database was employed to predict the target proteins for each active ingredient. CRC-related targets were obtained from the Genecards database, Online Mendelian Inheritance in Man (OMIM) database, Disease Gene Network (DisGeNET) database, and Therapeutic Target Database (TTD). Common targets were identified by intersecting the target proteins of all active ingredients with CRC-related targets. Protein-protein interactions (PPI) for the common target proteins were constructed using the String database and Cytoscape 3.9.1 software. Network topology analysis facilitated the identification of core targets. These core targets were subjected to enrichment analysis of Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) using the Metascape database. Molecular docking was performed using Discovery Studio 2019 to investigate the interactions between the active ingredients and core target proteins. The core targets were validated through bioinformatics analysis using GEPIA, HPA, and the cBioPortal database. Finally, a series of experiments were conducted to further validate the results in vitro.

RESULT

A total of 15 active ingredients and 255 herb targets were identified, resulting in 66 common targets in conjunction with 6113 disease targets. The PPI analysis highlighted AKT1, EGFR, CASP3, SRC, and ESR1 as core targets. KEGG enrichment analysis indicated significant enrichment in the PI3K-AKT signaling pathway, a pathway associated with cancer. Molecular docking experiments confirmed favorable interactions between dihydroguaiaretic acid and the core target proteins (AKT1, EGFR, CASP3, and ESR1). Bioinformatics analysis revealed differential expression of EGFR and CASP3 in normal and CRC tissues. Cellular experiments further verified that dihydroguaiaretic acid induces apoptosis in colorectal cancer cells through the PI3K-AKT signaling pathway.

CONCLUSION

Our network pharmacology study has elucidated that the Sargentodoxa cuneata-Patrinia villosa herb pair exerts the negative regulation of the PI3K/AKT/mTOR signaling pathway, ultimately leading to the induction of apoptosis in colorectal cancer cells. This research has predicted and validated the active ingredients, potential targets, and molecular mechanisms of Sargentodoxa cuneata-Patrinia villosa in the treatment of CRC, providing scientific evidence for the use of traditional Chinese medicine in managing CRC.

Plant Secondary Metabolites against Skin Photodamage: Mexican Plants, a Potential Source of UV-Radiation Protectant Molecules

Human skin works as a barrier against the adverse effects of environmental agents, including ultraviolet radiation (UVR). Exposure to UVR is associated with a variety of harmful effects on the skin, and it is one of the most common health concerns. Solar UVR constitutes the major etiological factor in the development of cutaneous malignancy. However, more than 90% of skin cancer cases could be avoided with appropriate preventive measures such as regular sunscreen use. Plants, constantly irradiated by sunlight, are able to synthesize specialized molecules to fight against UVR damage. Phenolic compounds, alkaloids and carotenoids constitute the major plant secondary metabolism compounds with relevant UVR protection activities. Hence, plants are an important source of molecules used to avoid UVR damage, reduce photoaging and prevent skin cancers and related illnesses. Due to its significance, we reviewed the main plant secondary metabolites related to UVR protection and its reported mechanisms. In addition, we summarized the research in Mexican plants related to UV protection. We presented the most studied Mexican plants and the photoprotective molecules found in them. Additionally, we analyzed the studies conducted to elucidate the mechanism of photoprotection of those molecules and their potential use as ingredients in sunscreen formulas.

Drugging the 'undruggable'. Therapeutic targeting of protein-DNA interactions with the use of computer-aided drug discovery methods

Transcription factors (TFs) act as major oncodrivers in many cancers and are frequently regarded as high-value therapeutic targets. The functionality of TFs relies on direct protein-DNA interactions, which are notoriously difficult to target with small molecules. However, this prior view of the 'undruggability' of protein-DNA interfaces has shifted substantially in recent years, in part because of significant advances in computer-aided drug discovery (CADD). In this review, we highlight recent examples of successful CADD campaigns resulting in drug candidates that directly interfere with protein-DNA interactions of several key cancer TFs, including androgen receptor (AR), ETS-related gene (ERG), MYC, thymocyte selection-associated high mobility group box protein (TOX), topoisomerase II (TOP2), and signal transducer and activator of transcription 3 (STAT3). Importantly, these findings open novel and compelling avenues for therapeutic targeting of over 1600 human TFs implicated in many conditions including and beyond cancer.

Evaluation of Antioxidant and Anti-α-glucosidase Activities of Various Solvent Extracts and Major Bioactive Components from the Seeds of Myristica fragrans

Myristica fragrans is a well-known species for flavoring many food products and for formulation of perfume and medicated balm. It is also used to treat indigestion, stomach ulcers, liver disorders, and, as emmenagogue, diaphoretic, diuretic, nervine, and aphrodisiac. We examined antioxidant properties and bioactive compounds in various solvent extracts from the seeds of M. fragrans. Methanol, ethanol, and acetone extracts exhibited relatively strong antioxidant activities by 2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), superoxide radical, and hydroxyl radical scavenging tests. Furthermore, methanol extracts also displayed significant anti-α-glucosidase activity. Examined and compared to the various solvent extracts for their chemical compositions using HPLC analysis, we isolated the ten higher content compounds and analyzed antioxidant and anti-α-glucosidase activities. Among the isolates, dehydrodiisoeugenol, malabaricone B and malabaricone C were main antioxidant components in seeds of M. fragrans. Malabaricone C exhibited stronger antioxidant capacities than others based on lower half inhibitory concentration (IC₅₀) values in DPPH and ABTS radical scavenging assays, and it also showed significant inhibition of α-glucosidase. These results shown that methanol was found to be the most efficient solvent for extracting the active components from the seeds of M. fragrans, and this material is a potential good source of natural antioxidant and α-glucosidase inhibitor.

Virtual screening by 2-D fingerprints, shape and docking for discovering new chemotypes of activator protein-1 inhibitors

Activator protein-1 Fos/Jun proteins bind to cognate DNA and regulate gene expression. Small-molecule inhibitors targeting activator protein-1 DNA binding have been developed in the past decades for therapeutic applications. Recent structural and in silico studies suggest a putative inhibitor binding pocket on the activator protein-1 structure, and computational modeling suggests a consensus binding mode of three classes of known small-molecule inhibitors. Here, virtual screening of two-dimensional fingerprints, shape, and docking was performed in search of novel chemotypes of activator protein-1 inhibitors. A standard score (Z₃-score) coalescing top-ranked ligands from the three methods was used and the top-scoring ligands were clustered by similarity. A representative ligand from each large cluster was evaluated using metadynamics simulations and molecular mechanics calculations. Representative hits showed diverse chemotypes and their modeled binding pose on activator protein-1 reproduced key interactions with binding site residues.Communicated by Ramaswamy H. Sarma.

Molecular modeling of non-covalent binding of Ligustrum lucidum secoiridoid glucosides to AP-1/matrix metalloproteinase pathway components

Ligustrum lucidum secoiridoid glucosides have been demonstrated to treat various types of diseases such as inflammation, pain, hepatotoxicity and hyperlipidermic as well as tonic for liver and kidney. Matrix metalloproteinases (MMPs) play a key role upon the pathology of photoaging. The present computational study showed that among the six secoiridoid glucosides (ligustroside, lucidumoside A, lucidumoside C, neonuezhenide, oleoside dimethylester, and oleuropein), ligustroside and lucidumoside A competitively inhibit all MMP-1, MMP-3, and MMP-9 activities in the docking models. The molecular docking analysis revealed a network of interactions between MMP-1, MMP-3, and MMP-9 and the ligands; ligustroside and lucidumoside A, and oxygen-containing and hydrophobic functional groups appear to be responsible for these enhanced interactions. The effect of ligustroside and lucidumoside A on the transcription factor AP-1 action was also investigated using molecular docking and dynamics simulations. The experiments suggested that inhibition of an AP-1-DNA complex formation could be on account of the direct interference of AP-1 binding onto the DNA binding sequence by ligustroside and lucidumoside A. The results suggest that both compounds have the highest potential for application as an anti-aging agent with the MMP inhibitory and anti-transcriptional activities.

Targeting c-FOS and DUSP1 abrogates intrinsic resistance to tyrosine-kinase inhibitor therapy in BCR-ABL-induced leukemia

Tyrosine kinase inhibitor (TKI) therapy for human cancers is not curative, with relapse due to the continuing presence of tumor cells, referred to as minimal residual disease (MRD) cells. MRD stem or progenitor cells survival in the absence of oncogenic kinase signaling, a phenomenon referred to as intrinsic resistance, depends on diverse growth factors. Here, we report that oncogenic kinase and growth factor signaling converge to induce the expression of the signaling proteins c-Fos and Dusp1. Genetic deletion of c-Fos and Dusp1 suppressed tumor growth in a BCR-ABL-induced mouse model of chronic myeloid leukemia (CML). Pharmacological inhibition of c-Fos, Dusp1 and BCR-ABL eradicated MRD in multiple in vivo models, as well as in primary CML patient xenotransplanted mice. Growth factor signaling also conferred TKI resistance and induced c-FOS and DUSP1 expression in tumor cells modeling other types of kinase-driven leukemias. Our data demonstrate that c-Fos and Dusp1 expression levels determine the threshold of TKI efficacy, such that growth factor-induced expression of c-Fos and Dusp1 confers intrinsic resistance to TKI therapy in a wide-ranging set of leukemias, and may represent a unifying Achilles heel of kinase-driven cancers.

Myristica fragrans Suppresses Tumor Growth and Metabolism by Inhibiting Lactate Dehydrogenase A

Most cancer cells predominantly produce ATP by maintaining a high rate of lactate fermentation, rather than by maintaining a comparatively low rate of tricarboxylic acid cycle, i.e., Warburg's effect. In the pathway, the pyruvate produced by glycolysis is converted to lactic acid by lactate dehydrogenase (LDH). Here, we demonstrated that water extracts from the seeds of Myristica fragrans Houtt. (MF) inhibit the in vitro enzymatic activity of LDH. MF effectively suppressed cell growth and the overall Warburg effect in HT29 human colon cancer cells. Although the expression of LDH-A was not changed by MF, both lactate production and LDH activity were decreased in MF-treated cells under both normoxic and hypoxic conditions. In addition, intracellular ATP levels were also decreased by MF treatment, and the uptake of glucose was also reduced by MF treatment. Furthermore, the experiment on tumor growth in the in vivo mice model revealed that MF effectively reduced the growth of allotransplanted Lewis lung carcinoma cells. Taken together, these results suggest that MF effectively inhibits cancer growth and metabolism by inhibiting the activity of LDH, a major enzyme responsible for regulating cancer metabolism. These results implicate MF as a potential candidate for development into a novel drug against cancer through inhibition of LDH activity.

Response to angiotensin blockade with irbesartan in a patient with metastatic colorectal cancer

BACKGROUND

A patient suffering from metastatic colorectal cancer, treatment-related toxicity and resistance to standard chemotherapy and radiation was assessed as part of a personalized oncogenomics initiative to derive potential alternative therapeutic strategies.

PATIENTS AND METHODS

Whole-genome and transcriptome sequencing was used to interrogate a metastatic tumor refractory to standard treatments of a patient with mismatch repair-deficient metastatic colorectal cancer.

RESULTS

Integrative genomic analysis indicated overexpression of the AP-1 transcriptional complex suggesting experimental therapeutic rationales, including blockade of the renin-angiotensin system. This led to the repurposing of the angiotensin II receptor antagonist, irbesartan, as an anticancer therapy, resulting in the patient experiencing a dramatic and durable response.

CONCLUSIONS

This case highlights the utility of comprehensive integrative genomic profiling and bioinformatics analysis to provide hypothetical rationales for personalized treatment options.

Polyphenol Compound as a Transcription Factor Inhibitor

A target-based approach has been used to develop novel drugs in many therapeutic fields. In the final stage of intracellular signaling, transcription factor–DNA interactions are central to most biological processes and therefore represent a large and important class of targets for human therapeutics. Thus, we focused on the idea that the disruption of protein dimers and cognate DNA complexes could impair the transcriptional activation and cell transformation regulated by these proteins. Historically, natural products have been regarded as providing the primary leading compounds capable of modulating protein–protein or protein-DNA interactions. Although their mechanism of action is not fully defined, polyphenols including flavonoids were found to act mostly as site-directed small molecule inhibitors on signaling. There are many reports in the literature of screening initiatives suggesting improved drugs that can modulate the transcription factor interactions responsible for disease. In this review, we focus on polyphenol compound inhibitors against dimeric forms of transcription factor components of intracellular signaling pathways (for instance, c-jun/c-fos (Activator Protein-1; AP-1), c-myc/max, Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and β-catenin/T cell factor (Tcf)).

Small molecule inhibitors targeting activator protein 1 (AP-1)

Activator protein 1 (AP-1) is a pivotal transcription factor that regulates a wide range of cellular processes including proliferation, apoptosis, differentiation, survival, cell migration, and transformation. Accumulating evidence supports that AP-1 plays an important role in several severe disorders including cancer, fibrosis, and organ injury, as well as inflammatory disorders such as asthma, psoriasis, and rheumatoid arthritis. AP-1 has emerged as an actively pursued drug discovery target over the past decade. Excitingly, a selective AP-1 inhibitor T-5224 (51) has been investigated in phase II human clinical trials. Nevertheless, no effective AP-1 inhibitors have yet been approved for clinical use. Despite significant advances achieved in understanding AP-1 biology and function, as well as the identification of small molecules modulating AP-1 associated signaling pathways, medicinal chemistry efforts remain an urgent need to yield selective and efficacious AP-1 inhibitors as a viable therapeutic strategy for human diseases.

In Silico Inhibition Studies of Jun-Fos-DNA Complex Formation by Curcumin Derivatives

Activator protein-1 (AP1) is a transcription factor that consists of the Jun and Fos family proteins. It regulates gene expression in response to a variety of stimuli and controls cellular processes including proliferation, transformation, inflammation, and innate immune responses. AP1 binds specifically to 12-O-tetradecanoylphorbol-13-acetate (TPA) responsive element 5′-TGAG/CTCA-3′ (AP1 site). It has been found constitutively active in breast, ovarian, cervical, and lung cancers. Numerous studies have shown that inhibition of AP1 could be a promising strategy for cancer therapeutic applications. The present in silico study provides insights into the inhibition of Jun-Fos-DNA complex formation by curcumin derivatives. These derivatives interact with the amino acid residues like Arg155 and Arg158 which play a key role in binding of Jun-Fos complex to DNA (AP1 site). Ala151, Ala275, Leu283, and Ile286 were the residues present at binding site which could contribute to hydrophobic contacts with inhibitor molecules. Curcumin sulphate was predicted to be the most potent inhibitor amongst all the natural curcumin derivatives docked.

Small molecule screening identifies regulators of the transcription factor ΔFosB

ΔFosB protein accumulates in the striatum in response to chronic administration of drugs of abuse, L-DOPA, or stress, triggering long lasting neural and behavioral changes that underlie aspects of drug addiction, abnormal involuntary movements (dyskinesia), and depression. ΔFosB binds AP-1 DNA consensus sequences found in promoters of many genes and can both repress or activate gene transcription. In the striatum, ΔFosB is thought to dimerize with JunD to form a functional transcription factor, though strikingly JunD does not accumulate in parallel. One explanation is that ΔFosB can recruit different partners, including itself, depending on the neuron type in which it is induced and the chronic stimulus, generating protein complexes with different effects on gene transcription. To develop chemical probes to study ΔFosB, a high-throughput screen was carried out to identify small molecules that modulate ΔFosB function. Two compounds with low micromolar activity, termed C2 and C6, disrupt the binding of ΔFosB to DNA via different mechanisms, and in in vitro assays stimulate ΔFosB-mediated transcription. In cocaine-treated mice, C2 significantly elevates mRNA levels of the AMPA glutamate receptor GluR2 subunit with specificity, a known target gene of ΔFosB that plays a role in drug addiction and endogenous resilience mechanisms. C2 and C6 show different activities against ΔFosB homodimers compared to ΔFosB/JunD heterodimers, suggesting that these compounds can be used as probes to study the contribution of different ΔFosB-containing complexes on the regulation of gene transcription in biological systems and to assess the utility of ΔFosB as a therapeutic target.

Small-molecule inhibitors of the AAA+ ATPase motor cytoplasmic dynein

The conversion of chemical energy into mechanical force by AAA+ (ATPases associated with diverse cellular activities) ATPases is integral to cellular processes, including DNA replication, protein unfolding, cargo transport, and membrane fusion¹. The AAA+ ATPase motor cytoplasmic dynein regulates ciliary trafficking², mitotic spindle formation³, and organelle transport⁴, and dissecting its precise functions has been challenging due to its rapid timescale of action and the lack of cell-permeable, chemical modulators. Here we describe the discovery of ciliobrevins, the first specific small-molecule antagonists of cytoplasmic dynein. Ciliobrevins perturb protein trafficking within the primary cilium, leading to their malformation and Hedgehog signaling blockade. Ciliobrevins also prevent spindle pole focusing, kinetochore-microtubule attachment, melanosome aggregation, and peroxisome motility in cultured cells. We further demonstrate the ability of ciliobrevins to block dynein-dependent microtubule gliding and ATPase activity in vitro. Ciliobrevins therefore will be useful reagents for studying cellular processes that require this microtubule motor and may guide the development of additional AAA+ ATPase superfamily inhibitors.

The effects of a synthetic curcuminoid analogue, 2,6-bis-(4-hydroxyl-3-methoxybenzylidine)cyclohexanone on proinflammatory signaling pathways and CLP-induced lethal sepsis in mice

We previously showed that 2,6-bis-(4-hydroxyl-3-methoxybenzylidine)cyclohexanone (BHMC), suppressed the synthesis of various proinflammatory mediators. In this study we explain the mechanism of action of BHMC in lipopolysaccharide (LPS)-induced U937 monocytes and further show that BHMC prevents lethality of CLP-induced sepsis. BHMC showed dose-dependent inhibitory effects on p38, JNK and ERK 1/2 activity as determined by inhibition of phosphorylation of downstream transcription factors ATF-2, c-Jun and Elk-1 respectively. Inhibition of these transcription factors subsequently caused total abolishment of AP-1-DNA binding. BHMC inhibited p65 NF-κB nuclear translocation and DNA binding of p65 NF-κB only at the highest concentration used (12.5μM) but failed to alter phosphorylation of JNK, ERK1/2 and STAT-1. Since the inhibition of p38 activity was more pronounced we evaluated the possibility that BHMC may bind to p38. Molecular docking experiments confirmed that BHMC fits well in the highly conserved hydrophobic pocket of p38 MAP kinase. We also show that BHMC was able to improve survival from lethal sepsis in a murine caecal-ligation and puncture (CLP) model.

Nordihydroguaiaretic acid is a potentin vitroscavenger of peroxynitrite, singlet oxygen, hydroxyl radical, superoxide anion and hypochlorous acid and preventsin vivoozone-induced tyrosine nitration in lungs

The antioxidant nordihydroguaiaretic acid (NDGA) has recently become well known as a putative anticancer drug. In this paper, it was evaluated the in vitro peroxynitrite (ONOO(-)), singlet oxygen ((1)O(2)), hydroxyl radical (OH(v)), hydrogen peroxide (H(2)O(2)), superoxide anion and hypochlorous acid (HOCl) scavenging capacity of NDGA. It was found that NDGA scavenges: (a) ONOO(-) (IC(50) = 4 +/- 0.94 microM) as efficiently as uric acid; (b) (1)O(2) (IC(50) = 151 +/- 20 microM) more efficiently than dimethyl thiourea, lipoic acid, N-acetyl-cysteine and glutathione; (c) OH(v) (IC(50) = 0.15 +/- 0.02 microM) more efficiently than dimethyl thiourea, uric acid, trolox, dimethyl sulfoxide and mannitol, (d) (IC(50) = 15 +/- 1 microM) more efficiently than N-acetyl-cysteine, glutathione, tempol and deferoxamine and (e) HOCl (IC(50) = 622 +/- 42 microM) as efficiently as lipoic acid and N-acetyl-cysteine. NDGA was unable to scavenge H(2)O(2). In an in vivo study in rats, NDGA was able to prevent ozone-induced tyrosine nitration in lungs. It is concluded that NDGA is a potent in vitro scavenger of ONOO(-), (1)O(2), OH(v), and HOCl and is able to prevent lung tyrosine nitration in vivo.

In vitro screening for the tumoricidal properties of international medicinal herbs

There is growing use of anticancer complementary and alternative medicines (CAMs) worldwide. The purpose of the current study is to assess a sizeable variety of natural and plant sources of diverse origin, to ascertain prospective research directives for cancer treatment and potential new chemotherapy drug sources. In this study, 374 natural extracts (10 microg/mL-5 mg/mL) were evaluated for dose-dependent tumoricidal effects using immortal neuroblastoma of spontaneous malignant origin. The findings indicate no pattern of tumoricidal effects by diverse plants with similar families/genus under the classes Pinopsida, Equisetopsida, Lycopodiosida, Filicosida, Liliopsida Monocotyledons or Magnoliopsida Dicotyledons. The results indicate that many of the most commonly used CAMs exhibited relatively weak tumoricidal effects including cats claw, astragalus, ginseng, echinacea, mistletoe, milk thistle, slippery elm, cayenne, chamomile, don quai, meadowsweet, motherwort and shepherd's purse. The data demonstrate that the most potent plant extracts were randomly dispersed within the plantae kingdom (LC(50) = 31-490 microg/mL) in order of the lowest LC(50) Dioscorea villosa (Dioscoreaceae) > Sanguinaria canadensis (Papaveraceae) > Dipsacus asper (Dipsacaceae) > Populus balsamifera (Salicaceae) > Boswellia carteri (Burseraceae) > Cyamopsis psoralioides (Fabaceae) > Rhamnus cathartica (Rhamnaceae) > Larrea tridentate (Zygophyllaceae) > Dichroa febrifuga (Hydrangeaceae) > Batschia canescens (Boraginaceae) > Kochia scoparia (Chenopodiaceae) > Solanum xanthocarpum (Solanaceae) > Opoponax chironium (Umbelliferae) > Caulophyllum thalictroides (Berberidaceae) > Dryopteris crassirhizoma (Dryopteridaceae) > Garcinia cambogia (Clusiaceae) > Vitex agnus-castus (Verbenaceae) > Calamus draco (Arecaceae). These findings show tumoricidal effect by extracts of wild yam root, bloodroot, teasel root, bakuchi seed, dichroa root, kanta kari, garcinia fruit, mace, dragons blood and the biblically referenced herbs: balm of gilead bud, frankincense and myrrh gum.

Tumor necrosis factor-related weak inducer of apoptosis augments matrix metalloproteinase 9 (MMP-9) production in skeletal muscle through the activation of nuclear factor-kappaB-inducing kinase and p38 mitogen-activated protein kinase: a potential role of MMP-9 in myopathy

Destruction of skeletal muscle extracellular matrix is an important pathological consequence of many diseases involving muscle wasting. However, the underlying mechanisms leading to extracellular matrix breakdown in skeletal muscle tissues remain unknown. Using a microarray approach, we investigated the effect of tumor necrosis factor-related weak inducer of apoptosis (TWEAK), a recently identified muscle-wasting cytokine, on the expression of extracellular proteases in skeletal muscle. Among several other matrix metalloproteinases (MMPs), we found that the expression of MMP-9, a type IV collagenase, was drastically increased in myotubes in response to TWEAK. The level of MMP-9 was also higher in myofibers of TWEAK transgenic mice. TWEAK increased the activation of both classical and alternative nuclear factor-kappaB (NF-kappaB) signaling pathways. Inhibition of NF-kappaB activity blocked the TWEAK-induced production of MMP-9 in myotubes. TWEAK also increased the activation of AP-1, and its inhibition attenuated the TWEAK-induced MMP-9 production. Overexpression of a kinase-dead mutant of NF-kappaB-inducing kinase or IkappaB kinase-beta but not IkappaB kinase-alpha significantly inhibited the TWEAK-induced activation of MMP-9 promoter. The activation of MMP-9 also involved upstream recruitment of TRAF2 and cIAP2 proteins. TWEAK increased the activity of ERK1/2, JNK1, and p38 MAPK. However, the inhibition of only p38 MAPK blocked the TWEAK-induced expression of MMP-9 in myotubes. Furthermore the loss of body and skeletal muscle weights, inflammation, fiber necrosis, and degradation of basement membrane around muscle fibers were significantly attenuated in Mmp9 knock-out mice on chronic administration of TWEAK protein. The study unveils a novel mechanism of skeletal muscle tissue destruction in pathological conditions.

Long-range enhancer associated with chromatin looping allows AP-1 regulation of the peptidylarginine deiminase 3 gene in differentiated keratinocyte

Transcription control at a distance is a critical mechanism, particularly for contiguous genes. The peptidylarginine deiminases (PADs) catalyse the conversion of protein-bound arginine into citrulline (deimination), a critical reaction in the pathophysiology of multiple sclerosis, Alzheimer's disease and rheumatoid arthritis, and in the metabolism of the major epidermal barrier protein filaggrin, a strong predisposing factor for atopic dermatitis. PADs are encoded by 5 clustered PADI genes (1p35-6). Unclear are the mechanisms controlling the expression of the gene PADI3 encoding the PAD3 isoform, a strong candidate for the deimination of filaggrin in the terminally differentiating epidermal keratinocyte. We describe the first PAD Intergenic Enhancer (PIE), an evolutionary conserved non coding segment located 86-kb from the PADI3 promoter. PIE is a strong enhancer of the PADI3 promoter in Ca2+-differentiated epidermal keratinocytes, and requires bound AP-1 factors, namely c-Jun and c-Fos. As compared to proliferative keratinocytes, calcium stimulation specifically associates with increased local DNase I hypersensitivity around PIE, and increased physical proximity of PIE and PADI3 as assessed by Chromosome Conformation Capture. The specific AP-1 inhibitor nordihydroguaiaretic acid suppresses the calcium-induced increase of PADI3 mRNA levels in keratinocytes. Our findings pave the way to the exploration of deimination control during tumorigenesis and wound healing, two conditions for which AP-1 factors are critical, and disclose that long-range transcription control has a role in the regulation of the gene PADI3. Since invalidation of distant regulators causes a variety of human diseases, PIE results to be a plausible candidate in association studies on deimination-related disorders or atopic disease.

Isolation and antifungal activity of lignans from Myristica fragrans against various plant pathogenic fungi

BACKGROUND

In a search for plant extracts with potent in vivo antifungal activity against various plant diseases, we found that treatment with a methanol extract of Myristica fragrans Houttyn (nutmeg) seeds reduced the development of various plant diseases. The objectives of the present study were to isolate and determine antifungal substances from My. fragrans and to evaluate their antifungal activities.

RESULTS

Three antifungal lignans were isolated from the methanol extract of My. fragrans seeds and identified as erythro-austrobailignan-6 (EA6), meso-dihydroguaiaretic acid (MDA) and nectandrin-B (NB). In vitro antimicrobial activity of the three lignans varied according to compound and target species. Alternaria alternata, Colletotrichum coccodes, C. gloeosporioides, Magnaporthe grisea, Agrobacterium tumefaciens, Acidovorax konjaci and Burkholderia glumae were relatively sensitive to the three lignans. In vivo, all three compounds effectively suppressed the development of rice blast and wheat leaf rust. In addition, EA6 and NB were highly active against the development of barley powdery mildew and tomato late blight, respectively. Both MDA and NB also moderately inhibited the development of rice sheath blight.

CONCLUSION

This is the first study to demonstrate the in vitro and in vivo antifungal activities of the three lignans from My. fragrans against plant pathogenic fungi.

Curcumin effects on inflammation and performance recovery following eccentric exercise-induced muscle damage

Downhill running is associated with fiber damage, inflammation, delayed-onset muscle soreness, and various functional deficits. Curcumin, a constituent of the Indian spice turmeric has been investigated for its anti-inflammatory activity and may offset some of the damage and functional deficits associated with downhill running. This study examined the effects of curcumin on inflammation and recovery of running performance following downhill running in mice. Male mice were assigned to downhill placebo (Down-Plac), downhill curcumin (Down-Cur), uphill placebo (Up-Plac), or uphill curcumin (Up-Cur) groups and run on a treadmill at 22 m/min at −14% or +14% grade, for 150 min. At 48 h or 72 h after the up/downhill run, mice ( experiment 1) underwent a treadmill performance run to fatigue. Another subset of mice was placed in voluntary activity wheel cages following the up/downhill run ( experiment 2) and their voluntary activity (distance, time and peak speed) was recorded. Additional mice ( experiment 3) were killed at 24 h and 48 h following the up/downhill run, and the soleus muscle was harvested for analysis of inflammatory cytokines (IL-1β, IL-6, and TNF-α), and plasma was collected for creatine kinase analysis. Downhill running decreased both treadmill run time to fatigue (48 h and 72 h) and voluntary activity (24 h) ( P < 0.05), and curcumin feedings offset these effects on running performance. Downhill running was also associated with an increase in inflammatory cytokines (24 h and 48 h) and creatine kinase (24 h) ( P < 0.05) that were blunted by curcumin feedings. These results support the hypothesis that curcumin can reduce inflammation and offset some of the performance deficits associated with eccentric exercise-induced muscle damage.

Interleukin-4 inhibition of interleukin-1-induced expression of matrix metalloproteinase-3 (MMP-3) is independent of lipoxygenase and PPARgamma activation in human gingival fibroblasts

Background

Interleukin 4 (IL-4) has been shown to suppress interleukin-1 (IL-1) induced expression of matrix metalloproteinase-3 (MMP-3) in human synovial and gingival fibroblasts, but the mechanism of suppression has not been determined. Activators of peroxisome proliferator-activated receptor-γ (PPARγ) have been shown to inhibit cytokine induced expression of MMPs in other cell types, and IL-4 has been shown to activate PPARγ by stimulating production of ligands through the lipoxygenase pathway. It has been suggested that PPARγ may inhibit expression of MMPs by competing with transcription factor AP-1 for binding to a putative composite binding element in the promoters. The objective of this study was to determine whether the suppressive effects of IL-4 on the IL-1 induced expression of MMP-3 involve activation of lipoxygenase and/or PPARγ.

Results

Western blotting revealed the presence of PPARγ in nuclear extract of HGF. IL-1 induced binding of nuclear extract to the putative composite PPRE/AP-1 site was diminished in the presence of pioglitazone, but there was no evidence of any change in the composition of the retarded complexes, and no evidence of PPARγ binding to this site. Nordihydroguaiaretic acid (NDGA), a non-selective lipoxygenase inhibitor, and MK886, a specific inhibitor of 5-lipoxygenase, induced MMP-3 expression synergistically with IL-1. However IL-4 was still able to inhibit MMP-3 expression in the presence of NDGA or MK886 and IL-1. Activation of PPARγ with pioglitazone not only failed to inhibit IL-1 induced expression of MMP-3 mRNA, but rather super-induced MMP-3 in the presence of IL-1. PPARγ antagonist GW9662 failed to abolish the suppressive effects of IL-4. Another PPARγ activator, 15-deoxy-Delta12,14prostaglandin J2 (15dPGJ2), also super-induced MMP-3 mRNA, and this was due at least in part to increased transcription.

Conclusion

IL-4 suppression of IL-1-induced MMP-3 expression in HGF is independent of lipoxygenase activity and activation of PPARγ. Super-induction of MMP-3 by pioglitazone may have important implications for patients using pioglitazone to treat type II diabetes in the presence of chronic inflammation.

A high-throughput cell-based assay to identify specific inhibitors of transcription factor AP-1

The oncogenic transcription factor AP-1 (activator protein-1) is required for tumor promotion and progression. Identification of novel and specific AP-1 inhibitors would be beneficial for cancer prevention and therapy. The authors have developed a high-throughput assay to screen synthetic and natural product libraries for noncytotoxic inhibitors of mitogen-activated AP-1 activity. The cell-based high-throughput screen is conducted in a 384-well format using a fluorescent resonance energy transfer (FRET) substrate to quantify the activity of a beta-lactamase reporter under the control of an AP-1-dependent promoter. The ratiometric FRET readout makes this assay extremely robust and reproducible, particularly for use with natural product extracts. To eliminate false positives due to cell killing, a cytotoxicity assay was incorporated. The AP-1 beta-lactamase reporter was validated with inhibitors of kinases located upstream of AP-1 and with known natural product inhibitors of AP-1 (nordihydroguaiaretic acid and curcumin). The assay was able to identify other known AP-1 inhibitors and protein kinase C modulators, as well as a number of chemically diverse compounds with unknown mechanisms of action from natural products libraries. Application to natural product extracts identified hits from a range of taxonomic groups. Screening of synthetic compounds and natural products should identify novel AP-1 inhibitors that may be useful in the prevention and treatment of cancers.

Anticariogenic activity of macelignan isolated from Myristica fragrans (nutmeg) against Streptococcus mutans

The occurrence of dental caries is mainly associated with oral pathogens, especially cariogenic Streptococcus mutans. Preliminary antibacterial screening revealed that the extract of Myristica fragrans, widely cultivated for the spice and flavor of foods, possessed strong inhibitory activity against S. mutans. The anticariogenic compound was successfully isolated from the methanol extract of M. fragrans by repeated silica gel chromatography, and its structure was identified as macelignan by instrumental analysis using 1D-NMR, 2D-NMR and EI-MS. The minimum inhibitory concentration (MIC) of macelignan against S. mutans was 3.9 microg/ml, which was much lower than those of other natural anticariogenic agents such as 15.6 microg/ml of sanguinarine, 250 microg/ml of eucalyptol, 500 microg/ml of menthol and thymol, and 1000 microg/ml of methyl salicylate. Macelignan also possessed preferential activity against other oral microorganisms such as Streptococcus sobrinus, Streptococcus salivarius, Streptococcus sanguis, Lactobacillus acidophilus and Lactobacillus casei in the MIC range of 2-31.3 microg/ml. In particular, the bactericidal test showed that macelignan, at a concentration of 20 microg/ml, completely inactivated S. mutans in 1 min. The specific activity and fast-effectiveness of macelignan against oral bacteria strongly suggest that it could be employed as a natural antibacterial agent in functional foods or oral care products.

Discovery of nonpeptidic small-molecule AP-1 inhibitors: lead hopping based on a three-dimensional pharmacophore model

We designed and synthesized small-molecule activator protein-1 (AP-1) inhibitors based on a three-dimensional (3D) pharmacophore model that we had previously derived from a cyclic decapeptide exhibiting AP-1 inhibitory activity. New AP-1 inhibitors with a 1-thia-4-azaspiro[4.5]decane or a benzophenone scaffold, which inhibit the DNA-binding and transactivation activities of AP-1, were discovered using a "lead hopping" procedure. An additional investigation of the benzophenone analogues confirmed the reliability of the pharmacophore model, its utility to discover AP-1 inhibitors, and the potency of the benzophenone derivatives as a lead series.

Multiple biological activities of curcumin: a short review

Turmeric (Curcuma longa rhizomes), commonly used as a spice is well documented for its medicinal properties in Indian and Chinese systems of medicine. It has been widely used for the treatment of several diseases. Epidemiological observations, though inconclusive, are suggestive that turmeric consumption may reduce the risk of some form of cancers and render other protective biological effects in humans. These biological effects of turmeric have been attributed to its constituent curcumin that has been widely studied for its anti-inflammatory, anti-angiogenic, anti-oxidant, wound healing and anti-cancer effects. As a result of extensive epidemiological, clinical, and animal studies several molecular mechanisms are emerging that elucidate multiple biological effects of curcumin. This review summarizes the most interesting in vitro and in vivo studies on the biological effects of curcumin.

Honokiol inhibits TNF-α-stimulated NF-κB activation and NF-κB-regulated gene expression through suppression of IKK activation

Honokiol, a small molecular weight lignan originally isolated from Magnolia officinalis, shows anti-angiogenic, anti-invasive and anti-proliferative activities in a variety of cancers. In this study, we investigated whether honokiol affects the transcription factor nuclear factor-kappa B (NF-kappaB) which controls a large number of genes involved in angiogenesis, metastasis and cell survival. We observed that the tumor necrosis factor-alpha (TNF-alpha)-induced NF-kappaB activation was blocked by honokiol in four different cancer cell lines as evidenced by EMSA. Honokiol did not directly affect the NF-kappaB-DNA binding. Immunoblot experiments demonstrated that honokiol inhibited the TNF-alpha-stimulated phosphorylation and degradation of the cytosolic NF-kappaB inhibitor IkappaBalpha. Furthermore, honokiol suppressed the intrinsic and TNF-alpha-stimulated upstream IkappaB kinases (IKKs) activities measured by a non-radioactive kinase assay using immunoprecipitated IKKs, suggesting a critical role of honokiol in abrogating the phosphorylation and degradation of IkappaBalpha. In a HeLa cell NF-kappaB-dependent luciferase reporter system, honokiol suppressed luciferase expression stimulated by TNF-alpha and by the transient transfection and expression of NIK (NF-kappaB-inducing kinase), wild type IKKbeta, constitutively active IKKalpha and IKKbeta, or the p65 subunit. Honokiol was also found to inhibit the nuclear translocation and phosphorylation of p65 subunit of NF-kappaB. RT-PCR results showed that honokiol suppressed NF-kappaB-regulated inflammatory and carcinogenic gene products including MMP-9, TNF-alpha, IL-8, ICAM-1 and MCP-1. In line with the observation that NF-kappaB activation may up-regulate anti-apoptotic genes, it was shown that honokiol enhanced TNF-alpha-induced apoptotic cell death. In summary, our results demonstrate that honokiol suppresses NF-kappaB activation and NF-kappaB-regulated gene expression through the inhibition of IKKs, which provides a possible mechanism for its anti-tumor actions.

Modulation of differentiation-related gene 1 expression by cell cycle blocker mimosine, revealed by proteomic analysis

L-mimosine, a plant amino acid, can reversibly block mammalian cells at late G1 phase and has been found to affect translation of mRNAs of the cyclin-dependent kinase inhibitor p27, eIF3a (eIF3 p170), and ribonucleotide reductase M2. The effect of mimosine on the expression of these genes may be essential for the G1 phase arrest. To determine additional genes that may be early respondents to the mimosine treatment, we performed two-dimensional gel electrophoretic analysis of [35S]methionine-labeled cell lysates followed by identification of the altered protein spots by LC-tandem mass spectrometry. In this study, the synthesis of two protein spots (MIP42 and MIP17) was found to be enhanced by mimosine, whereas the formation of another protein spot (MSP17) was severely blocked following mimosine treatment. These protein spots, MIP42, MIP17, and MSP17, were identified to be differentiation-related gene 1 (Drg-1; also called RTP, cap43, rit42, Ndrg-1, and PROXY-1), deoxyhypusine-containing eIF5A intermediate, and mature hypusine-containing eIF5A, respectively. The effect of mimosine on eIF5A maturation was due to inhibition of deoxyhypusine hydroxylase, the enzyme catalyzing the final step of hypusine biosynthesis in eIF5A. The mimosine-induced expression of Drg-1 was mainly attributable to increased transcription likely by the c-Jun/AP-1 transcription factor. Because induction of Drg-1 is an early event after mimosine treatment and is observed before a notable reduction in the steady-state level of mature eIF5A, eIF5A does not appear to be involved in the modulation of Drg-1 expression.

Inhibition of AP-1 transcription activator induces myc-dependent apoptosis in HL60 cells

Transcriptional activation of AP-1 is intricately involved in cell proliferation and transformation. The natural product, nordihydroguaiaretic acid (NDGA) shows an inhibitory effect on the binding of jun/AP-1 protein to the AP-1 site in 12-O-tetradecanoylphorbol-13-acetate (TPA)-stimulated HL60 cells. The NDGA inhibits the auto-regulated de novo synthesis of c-jun mRNA in TPA-stimulated HL60 cells. Our data also determine that this compound induces proliferation inhibition and apoptosis in human leukemia HL60 cells. To obtain information on the functional role of the AP-1 inhibition by NDGA in apoptosis signaling, the effects of pharmacological inhibition of AP-1 binding on c-myc, p53, and bax protein level were determined. Our results indicate that treatment of cells with NDGA enhances c-myc, p53, and bax protein levels. To rule out the possibility that NDGA will induce apoptosis because of the effects on proteins other than AP-1, we investigated the effect of another AP-1 inhibitor, SP600125, which is specific to Jun-N-terminal kinase. SP600125 decreased not only the phosphorylation level of jun protein but also AP-1/DNA binding activity. Also, apoptosis was observed to be induced by SP600125, concomitant with the increase in c-myc, p53, and bax protein level. In addition, apoptosis induced by both AP-1 inhibitors was accompanied by the activation of a downstream apoptotic cascade such as caspase 9, caspase 3, and poly[ADP-ribose]polymerase (PARP). When the cells were treated with NDGA or SP600125 in the presence of antisense c-myc oligonucleotides, apoptosis was not observed and an increase of c-myc, p53, and bax proteins was not manifested. All these results show that the inhibition of the transcription factor AP-1 action is related with either the drug-induced apoptosis or the drug toxicity of the HL60 cells. The apoptosis induced by AP-1 inhibition may be dependent on c-myc protein levels suggesting that the c-myc protein induces apoptosis at a low level of AP-1 binding activity. Altogether, our findings suggest that the presence of the AP-1 signal acts as a survival factor that determines the outcome of myc-induced proliferation or apoptosis.

Development of a high-throughput plate-based chemiluminescent transcription factor assay

Transcription factors are DNA-binding proteins that regulate the expression of specific genes by controlling transcription initiation. Two families of transcription factors, NFkappaB and AP-1, play pivotal roles in controlling important cellular processes ranging from normal cell growth and differentiation to apoptosis and cancer. Identifying changes in the DNA-binding activity of these factors is essential to understanding the regulation of these processes. We have developed a high-throughput DNA-based ELISA capable of monitoring activated levels of NFkappaB (p50 and p65) and AP-1 (c-Jun and c-Fos). This chemiluminescent assay utilizes a 96-well plate format, eliminating the throughput challenges imposed by traditional gel shift assays and exceeding the sensitivity and dynamic range of standard colorimetric detection systems. The sensitivity of this assay enables distinction between subtle as well as dramatic differences in the DNA-binding activity of these factors that result from the treatment of cells with various inhibitors or activating agents.

Synthetic curcumin analogs inhibit activator protein-1 transcription and tumor-induced angiogenesis

In a previous study, we observed that some synthetic curcumin analogs inhibited complex formations between Fos-Jun heterodimer and activator protein-1 (AP-1) DNA. These curcumin analogs have been observed to repress the AP-1 transcription in AP-1-transfected cells and they also inhibited the increased expression of Jun/AP-1 protein by 12-O-tetradecanoylphorbol-13-acetate (TPA) in the same cells. After the AP-1 inhibition by curcumin analogs in TPA-treated HT-1080 human fibrosarcoma cells, a decrease in mRNA expression of c-jun and MMP3 (stromelysin-1) has been observed. We also observed that curcumin analogs down-regulated the expression of MMP-9 (gelatinase-B), correlating with cellular invasion and migration in conditions such as tumor invasion and metastasis, through the electrophoretic mobility shift assay and gelatin zymography methods. Curcumin analogs showed an inhibitory effect on angiogenesis by various test methods including chicken chorioallantoic membrane assay, wound migration assay, invasion assay, and tube formation assay. Through the reverse transcriptase-polymerase chain reaction experiment, we confirmed that curcumin analogs down-regulated the expression of angiogenesis-associated genes, VEGF and MMP-9.

Expression of angiogenic factors vascular endothelial growth factor and interleukin-8/CXCL8 is highly responsive to ambient glutamine availability: role of nuclear factor-kappaB and activating protein-1

Vascular endothelial growth factor (VEGF) and interleukin-8/CXCL8 (IL-8) are prominent pro-angiogenic and pro-metastatic proteins that represent negative prognostic factors in many types of cancer. Hypoxia is thought to be the primary environmental cause of VEGF and IL-8 expression in solid tumors. We hypothesized that a lack of nutrients other than oxygen could stimulate the expression of these factors and previously demonstrated that expression of VEGF and IL-8 is responsive to amino acid deprivation. In the present study, we examined the effect of glutamine availability on the expression of these factors as well as the role of transcription factors NFkappaB and activating protein-1 (AP-1) in the response of TSE human breast carcinoma cells to glutamine deprivation. VEGF and IL-8 secretion and mRNA levels were dramatically induced by glutamine deprivation. mRNA stabilization contributed to this response. Glutamine deprivation increased NFkappaB (p65/p50) and AP-1 (Fra-1/c-Jun+JunD) DNA-binding activities. Blocking NFkappaB and AP-1 activation with curcumin as well as expression of dominant inhibitors, inhibitor of nuclear factor-kappaB (IkappaB) super repressor (IkappaBM), and a mutant form of c-Fos (A-Fos) demonstrated that the activation of NFkappaB and AP-1 transcription factors was necessary for the induction of IL-8 expression but dispensable for the induction of VEGF expression. A macro-array containing 111 NFkappaB target genes identified a total of 17 that were up-regulated 2-fold or more in response to glutamine deprivation. These included growth regulated oncogene alpha (GROalpha/GRO1/CXCL1), another neutrophil chemoattractant implicated in tumor angiogenesis and metastasis.

Design, synthesis, and biological evaluation of new cyclic disulfide decapeptides that inhibit the binding of AP-1 to DNA

The transcription factor activator protein-1 (AP-1) is an attractive target for the treatment of immunoinflammatory diseases, such as rheumatoid arthritis. Using the three-dimensional (3D) X-ray crystallographic structure of the DNA-bound basic region leucine zipper (bZIP) domains of AP-1, new cyclic disulfide decapeptides were designed and synthesized that demonstrated AP-1 inhibitory activities. The most potent inhibition was exhibited by Ac-c[Cys-Gly-Gln-Leu-Asp-Leu-Ala-Asp-Gly-Cys]-NH2 (peptide 2) (IC50 = 8 microM), which was largely due to the side chains of residues 3-6 and 8 of the peptide, as shown by an alanine scan. To provide structural information about the biologically active conformation of peptide 2, the structures of peptide 2 derived from molecular dynamics simulation of the bZIP-peptide 2 complex with explicit water molecules were superimposed on the solution structures derived from NMR measurements of peptide 2 in water. These showed a strong structural similarity in the backbones of residues 3-7 and enabled the construction of a 3D pharmacophore model of AP-1 binding compounds, based on the chemical and structural features of the amino acid side chains of residues 3-7 in peptide 2.

Increase by FK960, a novel cognitive enhancer, in glial cell line-derived neurotrophic factor production in cultured rat astrocytes

We examined the effect of N-(4-acetyl-1-piperazinyl)-p-fluorobenzamide monohydrate (FK960), a novel anti-dementia drug, on neurotrophic factor production in cultured rat astrocytes. FK960 (100nM) increased mRNA and protein levels of glial cell line-derived neurotrophic factor (GDNF). FK960 did not affect mRNA levels of neurotrophic factors other than GDNF. The effect of FK960 was not affected by antagonists of dopamine and alpha7-nicotinic acetylcholine receptors. FK960 stimulated phosphorylation of mitogen-activated protein/extracellular signal-regulated kinase (ERK) without any effect on phosphoryolation of p38 and c-Jun N-terminal kinase. FK960 increased the levels of c-Fos and phosphorylation of cAMP responsive element binding protein (CREB). The effect of FK960 on c-Fos was inhibited by PD98059 (10microM), an ERK kinase inhibitor, and cycloheximide (1microg/ml), a transcription inhibitor, and the effect of FK960 on CREB phosphorylation was blocked by PD98059. The effect of FK960 on GDNF mRNA expression was attenuated by PD98059, curcumin (10microM), an activator protein-1 inhibitor, cycloheximide and actinomycin D (10microg/ml). These results suggest that FK960 stimulates GDNF production in c-Fos- and CREB-dependent mechanisms in cultured astrocytes and that ERK signal is responsible for both c-Fos expression and CREB phosphorylation in the cascades.

Determination of binding constant of transcription factor myc-max/max-max and E-box DNA: the effect of inhibitors on the binding

The truncated myc and max proteins, only containing basic regions and helix-loop-helix/zipper (b/HLH/Zip) regions were over-expressed in E. coli and used for the determination of the binding constant and of the inhibitory mechanism on myc-max (or max-max)-DNA complex formation. The association kinetic constants (k(1) and k(-1)) of truncated max-max or myc-max dimer and DNA were determined as k(1)=(1.7+/-0.6)x10(5) M(-1) s(-1), k(-1)=(3.4+/-1.2)x10(-2) s(-1) for max-max and DNA or k(1)=(2.1+/-0.7)x10(5) M(-1) s(-1), k(-1)=(3.2+/-1.4)x10(-2) s(-1) for myc-max and DNA. The equilibrium binding constant (K(1)) was determined using these kinetic parameters [K(XXD)=(7.8+/-2.6)x10(6) M(-1) for max-max and DNA or K(XYD)=(6.9+/-2.2)x10(6) M(-1) for myc-max and DNA]. The binding constants of myc-max or max-max dimer formation were K(XX)=(2.6+/-0.9)x10(5) M(-1) or K(XY)=(1.3+/-0.4)x10(4) M(-1), respectively. When truncated proteins were used, the max-max dimer formation was easier than the myc-max dimer formation, contrary to the physiologically determined case. This leads us to deduce that domains other than b/HLH/Zip are very important for the transcriptional regulatory activity in physiological conditions. The truncated myc and max proteins, which were expressed in E. coli and contained only b/HLH/Zip regions were also used for the screening of inhibitors of myc-max-DNA complex formation. A synthesized curcuminoid, 1,7-bis(4-methyl-3-nitrophenyl)-1,6-heptadiene-3,5-dione (curcuminoid 004), showed the most potent inhibition out of the synthesized curcuminoids, in competition with DNA. The dissociation constant of max-max dimer and the inhibitor was 9 microM, when investigated using in vitro expressed b/HLH/Zip dimer proteins. The curcuminoid 004 showed an inhibitory effect on the binding of myc-max protein to the E-box element in SNU16 cells, and suppressed the expression of myc target genes including ornithine decarboxylase (ODC), cdc25a and c-myc in myc over-expressed human stomach cancer cell line SNU16.

Rasagenthi lehyam (RL) a novel complementary and alternative medicine for prostate cancer

PURPOSE

The use of complementary and alternative medicine (CAM) in cancer has been increasing. The therapeutic modalities which originated from India, viz., Ayurveda and Siddha, have phytotherapy as their fundamental basis and, therefore, produce few side effects. They are among the most ancient medicinal systems and are still being practiced in India and elsewhere, to cure cancer and other diseases. Many Siddha practitioners in the southern parts of India prescribe rasagenthi lehyam (RL) as a drug for cancer. RL contains 38 different botanicals, many of which have been shown to possess therapeutic efficacy, and 8 inorganic compounds, all prepared into a paste in a palm sugar and hen's egg base. The efficacy of RL in killing prostate cancer cells in vitro was investigated in this study to determine whether RL could be recommended as a CAM for prostate cancer.

METHODS

In order to scientifically validate the anticancer activity of RL on prostate cancer, a methanolic extract of RL was serially extracted with four organic solvents, and the extracts were tested for clonogenic inhibition and induction of apoptosis in PC-3 prostate cancer cells, with and without irradiation. n-Hexane, ethyl acetate and chloroform extracts of RL effectively killed PC-3 cells.

RESULTS

The IC(50) values of n-hexane, ethyl acetate and chloroform extracts of RL were 3.84 microg/ml, 3.68 microg/ml and 75 ng/ml, respectively. All three extracts induced apoptosis in PC-3 cells. Further, all the three extracts when combined with radiation, caused enhanced effect on killing of PC-3 cells. Among the three extracts, the chloroform extract showed the most significant radiation-sensitizing effect.

CONCLUSION

RL, either in its original formulation prepared under strict quality control or its chloroform extract, could potentially be an alternative medicine for prostate cancer, and also a sensitizing agent in the context of radiation therapy for prostate cancer, as a complementary medicine. A more directed study could lead to the identification of the active principle(s) in the chloroform extract of RL for use in prostate cancer therapy.

Estrogenic activity of an antioxidant, nordihydroguaiaretic acid (NDGA)

Nordihydroguaiaretic acid (NDGA), an antioxidant which has been used to preserve oils and foods, has recently become well known as a putative anticancer agent. Although NDGA is a member of the lignan family, its hormonal activities have not been well investigated. Here we show that NDGA has in vitro estrogenic activity in the ERE-luc reporter system using NIH3T3 cells, and in the estrogen-responsive cell growth assay in a pituitary cell line, MtT/E-2. Uterotropic assay in rats indicated that NDGA has estrogenic activity in vivo as well, albeit weak. Interestingly it preferentially induced ERalpha mediated ERE-luc activity, although it showed similar binding affinity to both ERalpha and ERbeta. With ERbeta, on the other hand, NDGA showed only weak agonistic action, and antagonized the estrogenic action of 17beta-estradiol when the two were coadministered. These data suggest that NDGA is an estrogenic agonist for ERalpha : ERE transcription and a mixed agonist/antagonist for ERbeta mediated ERE transactivation.

Oestrogen receptor beta (ERbeta) is abundantly expressed in normal colonic mucosa, but declines in colon adenocarcinoma paralleling the tumour's dedifferentiation

Oestrogen Receptor beta (ERbeta) may protect against prostate and mammary cell proliferation and malignant transformation. Epidemiological studies indicate that oestrogens may reduce colon cancer risk. Since ERalpha is minimally expressed in normal and malignant colon, the aim of this study was to investigate the expression of ERbeta in both normal colonic wall and colon cancer. ERbeta expression was evaluated by immunohistochemistry in 90 cases of colon adenocarcinoma and nearby (>30-cm away) normal colonic wall, using a monoclonal antibody. Moderate or strong nuclear immunostaining was detected in superficial and crypt epithelium, endothelial cells, vascular smooth muscle cells, lymphocytes, enteric neurons and smooth muscular cells of the normal colonic wall. Superficial epithelial cells in normal colon demonstrated a significantly higher ERbeta expression than colon adenocarcinoma cells in both genders. The decline in ERbeta expression paralleled the loss of differentiation of malignant colon cells, regardless of the tumour's localisation. These findings suggest a protective role for ERbeta against colon carcinogenesis.

Differential regulation of cytokines and transcription factors in liver by curcumin following hemorrhage/resuscitation

Inflammatory cytokines interleukin 1 (IL-1), IL-2, IL-6, and tumor necrosis factor-alpha (TNF-alpha) have been recognized as important mediators of pathophysiological and immunological events associated with shock. These inflammatory events after hemorrhage and resuscitation are characterized by the activation of transcription regulators such as nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1). Curcumin, an anti-inflammatory remedy used in Indian medicine, is known to suppress NF-kappaB and AP-1 activation and also to reduce ischemia-reperfusion injuries in animal models. Therefore, the aim of this study was to determine whether administration of curcumin before hemorrhagic shock has any salutary effects on cytokines and the redox-sensitive transcription factors NF-kappaB and AP-1. mRNA levels of IL-1alpha, IL-1beta, IL-2, IL-6, IL-10, and TNF-alpha were determined by reverse transcriptase-polymerase chain reaction in rat livers collected at 2 and 24 h after hemorrhage/resuscitation. The effect of curcumin on the activation of NF-kappaB and AP-1 was determined by electrophoretic mobility shift assays. Significant increases in the levels of liver cytokines IL-1alpha, IL-1beta, IL-2, IL-6, and IL-10 were observed in the 2-h posthemorrhage/resuscitation group compared with sham animals. In contrast, oral administration of curcumin for 7 days followed by hemorrhage/resuscitation regimen resulted in significant restoration of these cytokines to depleted levels, and, in fact, IL-1beta levels were lower than sham levels. Also, the 24-h postresuscitation group showed similar patterns with some exceptions. NF-kappaB and AP-1 were differentially activated at 2 and 24 h posthemorrhage and were inhibited by curcumin pretreatment. Serum aspartate transaminase estimates indicate decreased liver injury in curcumin-pretreated hemorrhage animals. These results suggest that protection against hemorrhage/resuscitation injury by curcumin pretreatment may result from the inactivation of transcription factors involved and regulation of cytokines to beneficial levels.

Unsaturated fatty acids bind Myc-Max transcription factor and inhibit Myc-Max-DNA complex formation

Oncoprotein Myc, hetero-dimerized with Max through a b/HLH/Zip region, is a transcription factor that governs important cellular processes such as cell cycle entry, proliferation and differentiation. We found that linoleic acid, isolated from Pollen Typhae, and other unsaturated fatty acids have strong inhibitory effects on the binding of Myc-Max heterodimer to an E-box DNA site (CA(C/T)GTG). The interaction of a fatty acid with a protein dimer, not with DNA, is assumed to block the entire Myc-Max-DNA complex formation. Unsaturated fatty acids also showed cytotoxicity against a SNU16 human stomach cancer cell line and conjugated linoleic acid suppressed mRNA expression of several myc-target genes; ornithine decarboxylase, p53, cdc25a in the SNU16 cells.

New and known symmetrical curcumin derivatives inhibit the formation of Fos-Jun-DNA complex

We previously reported that curcumin, the yellow pigment of turmeric, inhibited the formation of the Fos-Jun-DNA complex. Thus, we have synthesized 12 symmetrical curcuminoids. We used a slightly modified version of Pabon's method to search for an inhibitor more potent than curcumin. Of the synthesized curcuminoids, BJC005, CHC011, and CHC007 exhibited a remarkably high inhibitory activity. Their IC(50) values are 5.4 microM, 0.30 mM, and 0.38 mM, respectively. These IC(50) data indicated that BJC005 is nearly 90 times more effective than curcumin. The BJC005 has shown a more powerful profile than momordin, which, until now, has been reported as a potent Fos-Jun inhibitor. Also BJC005 and CHC007 have not been synthesized before. We report for the first time that the novel BJC005 and CHC007 exhibit highly inhibitory activity against transcription activity.

Design, synthesis, and biological evaluation of a cephalosporin-monohydroguaiaretic acid prodrug activated by a monoclonal antibody-beta-lactamase conjugate

A novel cephalosporin derivative of monohydroguaiaretic acid (cephem-M(3)N, 7) was synthesized and found to possess anticancer activity against human leukemia (K562), breast carcinoma (MCF7), human lung cancer (A549), human colon cancer (Colo205) and pancreatic cancer cells (Capan2 and MiaPaCa2). A tumor targeting fusion protein (dsFv3-beta-lactamase) was also used in conjunction with cephem-based M(3)N 7 and its potency toward K562, MCF7, A549, Colo205, Capan2, and MiaPaCa2 was found to approach that of the free M(3)N (4). In the presence of dsFv3-beta-lactamase, tumor cells were found to be much more susceptible to conjugate 7 than normal human embryonic lung (HEL) cells and normal fibroblasts (Hef522). These notions provide a new approach to the use of nordihydroguaiaretic acid (NDGA) and its derivatives for antitumor therapy.