The anti-inflammatory sesquiterpene lactone helenalin inhibits the transcription factor NF-kappaB by directly targeting p65

Critical role of the death receptor pathway in the antitumoral effects induced by hispanolone derivatives

Labdane diterpenoids have a broad spectrum of biological activities including antibacterial, antiviral and anti-inflammatory properties. However, little is known about their possible role in the apoptotic cell death machinery. Here, we report that hispanolone derivatives, a group of labdane diterpenoids, induce apoptosis in different tumor cell lines by activating caspase-8 with subsequent participation of mitochondrial signaling. Activation of caspase-8 by hispanolone derivatives was followed by a decrease in mitochondrial membrane potential, the release of apoptotic factors from mitochondria to the cytosol, and activation of caspases-9 and 3. Hispanolone derivatives also led to a time-dependent cleavage of Bid. Inhibition of caspase-8 abrogated these processes, suggesting that the death receptor pathway has a critical role in the apoptotic events induced by hispanolone derivatives. In addition, silencing death receptors with small interfering RNA s or pretreating cells with neutralizing antibodies to Fas ligand, tumor necrosis factor receptor 1 (TNF-R1), and TNF-α receptor 2 (TRAIL) inhibited diterpenoid-induced apoptosis, revealing it to be dependent on these death receptors. Interestingly, hispanolone derivatives had no effect on non-tumor cells. Consistently, in vivo bioluminescence imaging corroborates this antineoplasic effect, as hispanolone derivatives significantly decrease cancer growth in tumor xenograft assays. These data demostrate the antitumoral effects of hispanolone derivatives and provide relevant preclinical validation for the use of these compounds as potent therapeutic agents in cancer treatment.

Santonin-related compound 2 inhibits the nuclear translocation of NF-κB subunit p65 by targeting cysteine 38 in TNF-α-induced NF-κB signaling pathway

(11S)-2α-Bromo-3-oxoeudesmano-12,6α-lactone, designated santonin-related compound 2 (SRC2), only weakly affected IκBα degradation after tumor necrosis factor-α (TNF-α) stimulation, but strongly blocked the nuclear translocation of nuclear factor κB (NF-κB) subunit p65. Replacement of Cys-38 of p65 with serine abolished the inhibitory effect of SRC2 on this TNF-α-induced nuclear translocation. These results indicate that SRC2 inhibits the nuclear translocation of p65 by targeting Cys-38.

Artesunate Exerts a Direct Effect on Endothelial Cell Activation and NF-κB Translocation in a Mechanism Independent of Plasmodium Killing

Artemisinin and its derivates are an important class of antimalarial drug and are described to possess immunomodulatory activities. Few studies have addressed the effect of artesunate in the murine malaria model or its effect on host immune response during malaria infection. Herein, we study the effect of artesunate treatment and describe an auxiliary mechanism of artesunate in modulating the inflammatory response during experimental malaria infection in mice. Treatment with artesunate did not reduce significantly the parasitemia within 12 h, however, reduced BBB breakdown and TNF-α mRNA expression in the brain tissue of artesunate-treated mice. Conversely, mefloquine treatment was not able to alter clinical features. Notably, artesunate pretreatment failed to modulate the expression of LFA-1 in splenocytes stimulated with parasitized red blood cells (pRBCs) in vitro; however, it abrogated the expression of ICAM-1 in pRBC-stimulated endothelial cells. Accordingly, a cytoadherence in vitro assay demonstrated that pRBCs did not adhere to artesunate-treated vascular endothelial cells. In addition, NF-κB nuclear translocation in endothelial cells stimulated with pRBCs was impaired by artesunate treatment. Our results suggest that artesunate is able to exert a protective effect against the P. berghei-induced inflammatory response by inhibiting NF-κB nuclear translocation and the subsequent expression of ICAM-1.

Parthenolide suppresses tumor growth in a xenograft model of colorectal cancer cells by inducing mitochondrial dysfunction and apoptosis

Parthenolide (PT), a principal active component in medicinal plants, has been used conventionally to treat migraine and inflammation. This component has recently been reported to induce apoptosis in cancer cells, through mitochondrial dysfunction. In the present study, we investigated PT-mediated cell death signaling pathway by focusing on the involvement of Bcl-2 family members in human colorectal cancer cells. We also investigated the inhibitory effect of PT on tumor growth in xenografts. Using the human colorectal cancer cell lines HT-29, SW620 and LS174T, we demonstrated that treatment of these cancer cells with PT induces apoptosis using MTT, Annexin V assay and Hoechst 33258 staining. Apoptosis through the mitochondrial pathway was confirmed by detecting regulation of Bcl-2 family members, cytochrome c release and caspase activation. Moreover, intraperitoneal injection of PT showed significant inhibition of tumor growth, angiogenesis in the xenograft model. These results demonstrate that PT exhibits anti-cancer activity in human colorectal cancer in vitro and in vivo. These findings may also provide a novel approach for the treatment of colorectal cancer.

Alantolactone induces apoptosis in glioblastoma cells via GSH depletion, ROS generation, and mitochondrial dysfunction

Glioblastoma multiforme (GBM) is the most malignant and aggressive primary brain tumor in adults. Despite concerted efforts to improve current therapies, the prognosis of glioblastoma remains very poor. Alantolactone, a sesquiterpene lactone compound, has been reported to exhibit antifungal, antibacteria, antihelminthic, and anticancer properties. In this study, we found that alantolactone effectively inhibits growth and triggers apoptosis in glioblastoma cells in a time- and dose-dependent manner. The alantolactone-induced apoptosis was found to be associated with glutathione (GSH) depletion, reactive oxygen species (ROS) generation, mitochondrial transmembrane potential dissipation, cardiolipin oxidation, upregulation of p53 and Bax, downregulation of Bcl-2, cytochrome c release, activation of caspases (caspase 9 and 3), and cleavage of poly (ADP-ribose) polymerase. This alantolactone-induced apoptosis and GSH depletion were effectively inhibited or abrogated by a thiol antioxidant, N-acetyl-L-cysteine, whereas other antioxidant (polyethylene glycol (PEG)-catalase and PEG-superoxide-dismutase) did not prevent apoptosis and GSH depletion. Alantolactone treatment inhibited the translocation of NF-κB into nucleus; however, NF-κB inhibitor, SN50 failed to potentiate alantolactone-induced apoptosis indicating that alantolactone induces NF-κB-independent apoptosis in glioma cells. These findings suggest that the sensitivity of tumor cells to alantolactone appears to results from GSH depletion and ROS production. Furthermore, our in vivo toxicity study demonstrated that alantolactone did not induce significant hepatotoxicity and nephrotoxicity in mice. Therefore, alantolactone may become a potential lead compound for future development of antiglioma therapy.

NF-κB p65 repression by the sesquiterpene lactone, Helenalin, contributes to the induction of autophagy cell death

Background

Numerous studies have demonstrated that autophagy plays a vital role in maintaining cellular homeostasis. Interestingly, several anticancer agents were found to exert their anticancer effects by triggering autophagy. Emerging data suggest that autophagy represents a novel mechanism that can be exploited for therapeutic benefit. Pharmacologically active natural compounds such as those from marine, terrestrial plants and animals represent a promising resource for novel anticancer drugs. There are several prominent examples from the past proving the success of natural products and derivatives exhibiting anticancer activity. Helenalin, a sesquiterpene lactone has been demonstrated to have potent anti-inflammatory and antitumor activity. Albeit previous studies demonstrating helenalin’s multi modal action on cellular proliferative and apoptosis, the mechanisms underlying its action are largely unexplained.

Methods

To deduce the mechanistic action of helenalin, cancer cells were treated with the drug at various concentrations and time intervals. Using western blot, FACS analysis, overexpression and knockdown studies, cellular signaling pathways were interrogated focusing on apoptosis and autophagy markers.

Results

We show here that helenalin induces sub-G1 arrest, apoptosis, caspase cleavage and increases the levels of the autophagic markers. Suppression of caspase cleavage by the pan caspase inhibitor, Z-VAD-fmk, suppressed induction of LC3-B and Atg12 and reduced autophagic cell death, indicating caspase activity was essential for autophagic cell death induced by helenalin. Additionally, helenalin suppressed NF-κB p65 expression in a dose and time dependent manner. Exogenous overexpression of p65 was accompanied by reduced levels of cell death whereas siRNA mediated suppression led to augmented levels of caspase cleavage, autophagic cell death markers and increased cell death.

Conclusions

Taken together, these results show that helenalin mediated autophagic cell death entails inhibition of NF-κB p65, thus providing a promising approach for the treatment of cancers with aberrant activation of the NF-κB pathway.

Anti-inflammatory sesquiterpene lactones from Lychnophora trichocarpha Spreng. (Brazilian Arnica)

The aerial parts of Lychnophora trichocarpha Spreng. (Asteraceae) are used macerated in water or ethanol to treat inflammation, pain, rheumatism, contusions, bruises and insect bites in Brazilian traditional medicine. In this study, anti-inflammatory activity of ethanol extract from aerial parts of L. trichocarpha and its ethyl acetate fraction was investigated. Sesquiterpene lactones, lychnopholide (Lyc) and eremantholide C (EreC), isolated of ethyl acetate fraction, were also assayed for in vitro and in vivo anti-inflammatory activity. Topical treatment with ointments containing ethanol extract, its ethyl acetate fraction and sesquiterpene lactones significantly reduced carrageenan-induced mice paw oedema. In vitro assays demonstrated that Lyc inhibited interferon -γ/lipopolysaccharide -stimulated nitric oxide (NO) production in J774A.1 macrophages and increased production of IL-10 anti-inflammatory cytokine. The reduction of tumor necrosis factor-α (TNF-α) production by EreC was accompanied by an increased production of IL-10 in a concentration-dependent manner in J774A.1 macrophages. The anti-inflammatory effect of Lyc seems to involve the inhibition of production of NO and increased production of IL-10. The mechanism of the effect of EreC on the reduction of carrageenan-induced paw oedema may be attributed to inhibition of production of TNF-α and stimulation of IL-10 production. The results corroborate the use of ethanol extract from Lychnophora trichocarpha in folk medicine for anti-inflammatory action and indicate that the topical route is suitable for use.

Rel A/p65 is required for cytokine-induced myotube atrophy

Muscle atrophy can be triggered by systemic illnesses that are associated with elevated proinflammatory/catabolic cytokines, which, in turn, are thought to contribute to muscle wasting. In this study, we found that the prototypical NF-κB transcription factor, Rel A (p65), is required for NF-κB activation in C2C12 and L6 myotubes due to treatment with exogenous TNF-α, IL-1α, IL-1β, TNF-related weak inducer of apoptosis, but not IL-6. All five cytokines induced atrophy in C2C12 myotubes, and inhibition of p65 reversed atrophy due to TNF-α, IL-1α, IL-1β, TNF-related weak inducer of apoptosis, but not IL-6 treatment. p65 was also required for TNF-α-induced increase in atrophy and inflammatory gene expression. TNF-α- and IL-1β-treated myotubes increased IL-6 protein expression, but use of an IL-6 blocking antibody showed that the IL-6 production did not contribute to atrophy. These data show that p65 is a required transcription factor mediating the catabolic effects of four different cytokines in cultured myotubes, but IL-6 works by a different mechanism.

Chemical Composition of Essential Oils from a Multiple Shoot Culture of Telekia speciosa and Different Plant Organs

The composition of essential oil from Telekia speciosa leaves, flowers, roots, stems and in vitro regenerated shoots was studied by GC-MS-FID leading to the determination of 112 compounds. The qualitative composition of the essential oil from the examined plant material was similar, whereas quantities of individual components of the oils varied widely depending on the kind of plant material. The most striking differences were observed between the oils produced by aerial and underground parts of the intact plant, as well as between oils produced by in vitro grown shoots and leaves of the intact plant. The main volatiles of leaf essential oil were: ( E, E)-farnesol (21.2%) and ( E)-nerolidol (17.9%), while isoalantolactone was the predominant component of the root (62.3%) and flower oils (23.0%). Numerous thymol derivatives were also found, among them 10-isobutyryloxy-8,9-epoxythymol isobutyrate, which was one of the main components found in the flower oil (20.5%) and that from the in vitro cultures (20.2%).

Isoalantolactone induces reactive oxygen species mediated apoptosis in pancreatic carcinoma PANC-1 cells

Isoalantolactone, a sesquiterpene lactone compound possesses antifungal, antibacteria, antihelminthic and antiproliferative activities. In the present study, we found that isoalantolactone inhibits growth and induces apoptosis in pancreatic cancer cells. Further mechanistic studies revealed that induction of apoptosis is associated with increased generation of reactive oxygen species, cardiolipin oxidation, reduced mitochondrial membrane potential, release of cytochrome c and cell cycle arrest at S phase. N-Acetyl Cysteine (NAC), a specific ROS inhibitor restored cell viability and completely blocked isoalantolactone-mediated apoptosis in PANC-1 cells indicating that ROS are involved in isoalantolactone-mediated apoptosis. Western blot study showed that isoalantolactone increased the expression of phosphorylated p38 MAPK, Bax, and cleaved caspase-3 and decreased the expression of Bcl-2 in a dose-dependent manner. No change in expression of phosphorylated p38 MAPK and Bax was found when cells were treated with isoalantolactone in the presence of NAC, indicating that activation of these proteins is directly dependent on ROS generation. The present study provides evidence for the first time that isoalantolactone induces ROS-dependent apoptosis through intrinsic pathway. Furthermore, our in vivo toxicity study demonstrated that isoalantolactone did not induce any acute or chronic toxicity in liver and kidneys of CD1 mice at dose of 100 mg/kg body weight. Therefore, isoalantolactone may be a safe chemotherapeutic candidate for the treatment of human pancreatic carcinoma.

PI3-K/Akt/JNK/NF-κB is essential for MMP-9 expression and outgrowth in human limbal epithelial cells on intact amniotic membrane

Matrix metalloproteinase-9 (MMP-9) plays an important role in the outgrowth of expanded human limbal epithelial cells on intact amniotic membranes (AM). The mechanisms of MMP-9 expression and cell outgrowth remain unknown. Here, we demonstrated that MMP-9 is preferentially expressed at the leading edge of limbal epithelial outgrowth. Treatment with the inhibitors of PI3-K (LY294002), Akt (SH-5), MEK1/2 (U0126), and JNK1/2 (SP600125) attenuated the outgrowth area, indicating that PI3-K/Akt, p42/p44 MAPK, and JNK1/2 are involved in the outgrowth of intact AM-expanded limbal epithelial cells. However, MMP-9 expression at both transcriptional and translational levels was attenuated by treatment with SP600125, LY294002, or SH-5, not by U0126 and SB202190, suggesting that JNK1/2 and PI3-K/Akt participate in MMP-9 expression. Moreover, NF-κB phosphorylation and nuclear translocation was especially noted at the leading edge, which was attenuated by treatment with SP600125 or LY294002. Helenalin, a selective NF-κB inhibitor, reduced both the limbal epithelial outgrowth and MMP-9 expression. Finally, the data reveal that PI3-K/Akt is an upstream component of the JNK1/2 pathway in MMP-9 expression. Thus, both MAPKs and PI3-K/Akt are required for limbal epithelial outgrowth on intact AM, only the PI3-K/Akt/JNK is essential for MMP-9 expression mediated through activation of transcriptional factor NF-κB in this model.

Mechanisms involved in enhancement of the expression and function of aggrecanases by hyaluronan oligosaccharides

OBJECTIVE

Small hyaluronan (HA) oligosaccharides serve as competitive receptor antagonists to displace HA from the cell surface and induce cell signaling events. In articular chondrocytes, this cell signaling is mediated by the HA receptor CD44 and induces stimulation of genes involved in matrix degradation, such as matrix metalloproteinases (MMPs) as well as matrix repair genes including type II collagen, aggrecan, and HA synthase 2. The objective of this study was to determine changes in the expression and function of aggrecanases after disruption of chondrocyte CD44-HA interactions.

METHODS

Bovine articular chondrocytes or bovine cartilage tissue was pretreated with a variety of inhibitors of major signaling pathways prior to the addition of HA oligosaccharides. Changes in aggrecanase were monitored by real-time reverse transcription-polymerase chain reaction and Western blot analyses of ADAMTS-4, ADAMTS-5, and aggrecan proteolytic fragments. To test the interactions between ADAMTS-4 and membrane type 4 MMP (MT4-MMP), protein lysates purified from stimulated chondrocytes were subjected to coimmunoprecipitation.

RESULTS

Disruption of chondrocyte CD44-HA interactions with HA oligosaccharides induced the transcription of ADAMTS-4 and ADAMTS-5 in a time- and dose-dependent manner. The association of glycosyl phosphatidylinositol-anchored MT4-MMP with ADAMTS-4 was also induced in articular chondrocytes by HA oligosaccharides. Inhibition of the NF-κB pathway blocked HA oligosaccharide-mediated stimulation of aggrecanases.

CONCLUSION

Disruptive changes in chondrocyte-matrix interactions by HA oligosaccharides induce matrix degradation and elevate aggrecanases via the activation of the NF-κB signaling pathway.

VCAM-1 promotes osteolytic expansion of indolent bone micrometastasis of breast cancer by engaging α4β1-positive osteoclast progenitors

Breast cancer patients often develop locoregional or distant recurrence years after mastectomy. Understanding the mechanism of metastatic recurrence after dormancy is crucial for improving the cure rate for breast cancer. Here, we characterize a bone metastasis dormancy model to show that aberrant expression of vascular cell adhesion molecule 1 (VCAM-1), in part dependent on the activity of the NF-κB pathway, promotes the transition from indolent micrometastasis to overt metastasis. By interacting with the cognate receptor integrin α4β1, VCAM-1 recruits monocytic osteoclast progenitors and elevates local osteoclast activity. Antibodies against VCAM-1 and integrin α4 effectively inhibit bone metastasis progression and preserve bone structure. These findings establish VCAM-1 as a promising target for the prevention and inhibition of metastatic recurrence in bone.

VCAM-1 promotes osteolytic expansion of indolent bone micrometastasis of breast cancer by engaging α4β1-positive osteoclast progenitors

Breast cancer patients often develop locoregional or distant recurrence years after mastectomy. Understanding the mechanism of metastatic recurrence after dormancy is crucial for improving the cure rate for breast cancer. Here, we characterize a bone metastasis dormancy model to show that aberrant expression of vascular cell adhesion molecule 1 (VCAM-1), in part dependent on the activity of the NF-κB pathway, promotes the transition from indolent micrometastasis to overt metastasis. By interacting with the cognate receptor integrin α4β1, VCAM-1 recruits monocytic osteoclast progenitors and elevates local osteoclast activity. Antibodies against VCAM-1 and integrin α4 effectively inhibit bone metastasis progression and preserve bone structure. These findings establish VCAM-1 as a promising target for the prevention and inhibition of metastatic recurrence in bone.

AN AB INITIO STUDY ON THE STRUCTURE–CYTOTOXICITY RELATIONSHIP OF TERPENOID LACTONES BASED ON THE MICHAEL REACTION BETWEEN THEIR PHARMACOPHORES AND L-CYSTEINE-METHYLESTER-1

The cytotoxic effects of terpenoid lactones are attributed to the alkylation of biological nucleophiles, especially sulfhydryl groups in proteins, by the α,β-unsaturated carbonyl moiety of lactones through Michael reaction. Therefore, the cytotoxicity could be reflected by the reactivity of the pharmacophores. In this work, the Michael reaction between 12 α,β-unsaturated-carbonyl-containing small species, i.e. 10 analogues of the alpha methylene gamma butyrolactone moiety of andrographolide, one cyclopentenone, and one methylene–pentanolide, and L-cysteine-methylester-1 were investigated by ab initio methods to mimic the alkylation of proteins by terpenoid lactones. The trend in the calculated reaction free energies of the small species is qualitatively in accordance with the reported cytotoxicity of corresponding terpenoid lactones.

Inhibition of Myb-dependent gene expression by the sesquiterpene lactone mexicanin-I

The c-myb proto-oncogene encodes a transcription factor that is highly expressed in the progenitor cells of the hematopoietic system, where it regulates the expression of genes important for lineage determination, cell proliferation and differentiation. There is strong evidence that deregulation of c-myb expression is involved in the development of human tumors, particularly of certain types of leukemia, and breast and colon cancer. The c-Myb protein is therefore an interesting therapeutic target. Here, we have investigated the potential of natural sesquiterpene lactones (STLs), a class of compounds that are active constituents of a variety of medicinal plants, to suppress Myb-dependent gene expression. We have developed a test system that allows screening of compounds for their ability to interfere with the activation of Myb target genes. Using this assay system, we have identified the STL mexicanin-I as the first cell-permeable, low-molecular-weight inhibitor of Myb-induced gene expression.

Pseudoguaianolides and guaianolides from Inula hupehensis as potential anti-inflammatory agents

Eight new pseudoguaianolides (1-8), two new guaianolides (9 and 10), and 14 known sesquiterpenes were isolated from the aerial parts of Inula hupehensis. The structures were elucidated using spectroscopic methods and circular dichroism analysis. All compounds were tested for inhibitory activities against LPS-induced nitric oxide production in RAW264.7 macrophages. Compounds 13 and 22 were found to inhibit nitric oxide production potently, with IC50 values of 0.9 and 0.6 μM, respectively. Preliminary structure-activity relationships for these compounds are proposed.

The effect of dehydroleucodine in adipocyte differentiation

Dehydroleucodine (DhL) is a sesquiterpene lactone of the guaianolide group with gastric cytoprotective activity. Recent studies have also demonstrated that DhL inhibits the proliferation of vascular smooth muscle cells. In this study we examined the effect of DhL in the differentiation of 3T3-L1 preadipocytes. The addition of DhL significantly inhibited the differentiation of 3T3-L1 preadipocytes along with a significant decrease in the accumulation of lipid content by a dramatic downregulation of the expression of adipogenic-specific transcriptional factors PPARγ and C-EBPα. However, phosphorylation of AMPKα, Erk1/2 and Akt1 was not inhibited by DhL treatment. Interestingly, we also found that 11,13-dihydrodehydroleucodine, a derivative of DhL with inactivated α-methylene-γ-lactone function, also inhibited the differentiation of 3T3-L1 preadipocytes. Taken together, these data suggest that DhL has an important inhibitory effect in cellular pathways regulating adipocyte differentiation by modulating the PPARγ expression, which is known to play a pivotal role during adipogenesis.

Combinatorial effect of non-steroidal anti-inflammatory drugs and NF-κB inhibitors in ovarian cancer therapy

Several epidemiological studies have correlated the use of non-steroidal anti-inflammatory drugs (NSAID) with reduced risk of ovarian cancer, the most lethal gynecological cancer, diagnosed usually in late stages of the disease. We have previously established that the pro-apoptotic cytokine melanoma differentiation associated gene-7/Interleukin-24 (mda-7/IL-24) is a crucial mediator of NSAID-induced apoptosis in prostate, breast, renal and stomach cancer cells. In this report we evaluated various structurally different NSAIDs for their efficacies to induce apoptosis and mda-7/IL-24 expression in ovarian cancer cells. While several NSAIDs induced apoptosis, Sulindac Sulfide and Diclofenac most potently induced apoptosis and reduced tumor growth. A combination of these agents results in a synergistic effect. Furthermore, mda-7/IL-24 induction by NSAIDs is essential for programmed cell death, since inhibition of mda-7/IL-24 by small interfering RNA abrogates apoptosis. mda-7/IL-24 activation leads to upregulation of growth arrest and DNA damage inducible (GADD) 45 α and γ and JNK activation. The NF-κB family of transcription factors has been implicated in ovarian cancer development. We previously established NF-κB/IκB signaling as an essential step for cell survival in cancer cells and hypothesized that targeting NF-κB could potentiate NSAID-mediated apoptosis induction in ovarian cancer cells. Indeed, combining NSAID treatment with NF-κB inhibitors led to enhanced apoptosis induction. Our results indicate that inhibition of NF-κB in combination with activation of mda-7/IL-24 expression may lead to a new combinatorial therapy for ovarian cancer.

Reconstitution of the costunolide biosynthetic pathway in yeast and Nicotiana benthamiana

The sesquiterpene costunolide has a broad range of biological activities and is the parent compound for many other biologically active sesquiterpenes such as parthenolide. Two enzymes of the pathway leading to costunolide have been previously characterized: germacrene A synthase (GAS) and germacrene A oxidase (GAO), which together catalyse the biosynthesis of germacra-1(10),4,11(13)-trien-12-oic acid. However, the gene responsible for the last step toward costunolide has not been characterized until now. Here we show that chicory costunolide synthase (CiCOS), CYP71BL3, can catalyse the oxidation of germacra-1(10),4,11(13)-trien-12-oic acid to yield costunolide. Co-expression of feverfew GAS (TpGAS), chicory GAO (CiGAO), and chicory COS (CiCOS) in yeast resulted in the biosynthesis of costunolide. The catalytic activity of TpGAS, CiGAO and CiCOS was also verified in planta by transient expression in Nicotiana benthamiana. Mitochondrial targeting of TpGAS resulted in a significant increase in the production of germacrene A compared with the native cytosolic targeting. When the N. benthamiana leaves were co-infiltrated with TpGAS and CiGAO, germacrene A almost completely disappeared as a result of the presence of CiGAO. Transient expression of TpGAS, CiGAO and CiCOS in N. benthamiana leaves resulted in costunolide production of up to 60 ng.g(-1) FW. In addition, two new compounds were formed that were identified as costunolide-glutathione and costunolide-cysteine conjugates.

Direct Rel/NF-κB inhibitors: structural basis for mechanism of action

The Rel/NF-κB transcription factors have emerged as novel therapeutic targets for a variety of human diseases and pathological conditions, including inflammation, autoimmune diseases, cancer, ischemic injury, osteoporosis, transplant rejection and neurodegeneration. Several US FDA-approved drugs may, in part, attribute their therapeutic effects to the inhibition of the Rel/NF-κB pathway. Strategies for blocking the Rel/NF-κB signaling pathway have inspired the pharmaceutical industry to develop inhibitors for I-κB kinase, however, this article focuses instead on identifying natural compounds that directly target and inhibit DNA binding and transcription activity of Rel/NF-κB. These include compounds containing a quinone core, an α,β unsaturated carbonyl and a benzene diamine. By investigating the mechanisms of action of existing natural inhibitors, novel strategies and synthetic approaches can be devised that will facilitate the development of novel and selective Rel/NF-κB inhibitors with better safety profiles.

Natural and synthetic α,β-unsaturated carbonyls for NF-κB inhibition

BACKGROUND

The nuclear transcription factor NF-κB has gained considerable importance due to its major involvement in inflammation and constitutive activity in malignant cells. It is induced by a variety of stimuli and controls the expression of several proteins involved in biological processes. Numerous natural products and synthesized organic molecules have been reported to inhibit NF-κB and have played an integral role in identifying implicated pathways. Prominent among them are the sesquiterpene lactones, polyphenolic enones and other α,β-unsaturated carbonyl-containing molecules, particularly α-methylene-γ-butyrolactones.

DISCUSSION

This mini-review provides an introductory overview of some of the associated pathways involving NF-κB in cancer and discusses the structures and mode of action of natural α,β-unsaturated carbonyl-containing inhibitors and their synthetic counterparts. A review of the recent methods for the synthesis of α-alkylidene-γ-butyrolactones is also provided, with the aim of arousing the interest of synthetic chemists for the design and development of novel NF-κB inhibitors.

CONCLUSIONS

Modulating damaging effects without harming the inflammatory and immune responses are crucial parameters for developing NF-κB inhibitors. Examination of novel α,β-unsaturated carbonyls and the further discovery of simple methods to prepare such molecules should lead to the identification of site-specific inhibitors.

Helenalin bypasses Bcl-2-mediated cell death resistance by inhibiting NF-κB and promoting reactive oxygen species generation

Evasion of cell death by overexpression of anti-apoptotic proteins, such as Bcl-2, is commonly observed in cancer cells leading to a lack of response to chemotherapy. Hence, there is a need to find new chemotherapeutic agents that are able to overcome chemoresistance mediated by Bcl-2 and to understand their mechanisms of action. Helenalin, a sesquiterpene lactone (STL), induces cell death and abrogates clonal survival in a highly apoptosis-resistant Bcl-2 overexpressing Jurkat cell line as well as in two other Bcl-2 overexpressing solid tumor cell lines (mammary MCF-7; pancreatic L6.3pl). This effect is not achieved by directly affecting the mitochondria-protective function of Bcl-2 in the intrinsic pathway of apoptosis since Bcl-2 overexpressing Jurkat cells do not show cytochrome c release and dissipation of mitochondrial membrane potential upon helenalin treatment. Moreover, helenalin induces an atypical form of cell death with necrotic features in Bcl-2 overexpressing cells, neither activating classical mediators of apoptosis (caspases, AIF, Omi/HtrA2, Apaf/apoptosome) nor ER-stress mediators (BiP/GRP78 and CHOP/GADD153), nor autophagy pathways (LC3 conversion). In contrast, helenalin was found to inhibit NF-κB activation that was considerably increased in Bcl-2 overexpressing Jurkat cells and promotes cell survival. Moreover, we identified reactive oxygen species (ROS) and free intracellular iron as mediators of helenalin-induced cell death whereas activation of JNK and abrogation of Akt activity did not contribute to helenalin-elicited cell death. Our results highlight the NF-κB inhibitor helenalin as a promising chemotherapeutic agent to overcome Bcl-2-induced cell death resistance.

Anti-inflammatory activity of Lychnophora passerina, Asteraceae (Brazilian "Arnica")

ETHNOPHARMACOLOGICAL RELEVANCE

Lychnophora passerina (Asteraceae), popularly known as "arnica," is used to treat inflammation, pain, rheumatism, contusions, bruises and insect bites in Brazilian traditional medicine.

MATERIALS AND METHODS

The anti-inflammatory activity of crude ethanolic extract of aerial parts of L. passerina and its ethyl acetate and methanolic fractions had their abilities to modulate the production of NO, TNF-α and IL-10 inflammatory mediators in LPS/IFN-γ-stimulated J774.A1 macrophages evaluated. Moreover, the crude ethanolic extract and derived fractions were also in vivo assayed by carrageenan-induced paw oedema in mice.

RESULTS

In vitro assays showed remarkable anti-inflammatory activity of L. passerina crude ethanolic extract (EE) and its ethyl acetate (A) and methanolic (M) fractions, through the inhibition of production of NO and TNF-α inflammatory mediators and induction of production of IL-10 anti-inflammatory cytokine. In vivo assays showed anti-inflammatory activity for EE 10% ointment, similar to the standard drug diclofenac gel. The A and M fraction ointments 20% presented anti-inflammatory activity.

CONCLUSION

The results obtained showed that possible anti-inflammatory effects of EE and its A and M fractions may be attributed to inhibition pro-inflammatory cytokines production, TNF-α and NO and to increased IL-10 production. EE, A and M ointments showed topical in vivo anti-inflammatory activity. The in vivo anti-inflammatory activity of EE of L. passerina may be related to synergistic effects of different substances in the crude extract. Therefore, traditional use of aerial parts of L. passerina in the inflammatory conditions could be beneficial to treat topical inflammatory conditions, as evidenced by the present study.

Traumeel - an emerging option to nonsteroidal anti-inflammatory drugs in the management of acute musculoskeletal injuries

Musculoskeletal injuries are on the rise. First-line management of such injuries usually employs the RICE (rest, ice, compression, and elevation) approach to limit excessive inflammation. Nonsteroidal anti-inflammatory drugs (NSAIDs) are also commonly used to limit inflammation and to control pain. Traumeel^®, a preparation with bioregulatory effects is also used to treat the symptoms associated with acute musculoskeletal injuries, including pain and swelling. Traumeel is a fixed combination of biological and mineral extracts, which aims to apply stimuli to multiple targets to restore normal functioning of regulatory mechanisms. This paper presents the accumulating evidence of Traumeel’s action on the inflammatory process, and of its efficacy and tolerability in randomized trials, as well as observational and surveillance studies for the treatment of musculoskeletal injuries. Traumeel has shown comparable effectiveness to NSAIDs in terms of reducing symptoms of inflammation, accelerating recovery, and improving mobility, with a favorable safety profile. While continued research and development is ongoing to broaden the clinical evidence of Traumeel in acute musculoskeletal injury and to further establish its benefits, current information suggests that Traumeel may be considered as an anti-inflammatory agent that is at least as effective and appears to be better tolerated than NSAIDs.

Synthesis and biological evaluation of novel irreversible serine protease inhibitors using amino acid based sulfonyl fluorides as an electrophilic trap

We have designed and synthesized novel irreversible serine protease inhibitors containing aliphatic sulfonyl fluorides as an electrophilic trap. These substituted taurine sulfonyl fluorides derived from taurine or protected amino acids were conveniently synthesized from β-aminoethanesulfonyl chlorides using KF/18-crown-6 or from β-aminoethanesulfonates using DAST. Their potency of irreversible inhibition of serine proteases is described in different enzyme assays using chymotrypsin leading to binding affinities up to 22 μM.

SPLUNC1 regulation in airway epithelial cells: role of Toll-like receptor 2 signaling

Background

Respiratory infections including Mycoplasma pneumoniae (Mp) contribute to various chronic lung diseases. We have shown that mouse short palate, lung, and nasal epithelium clone 1 (SPLUNC1) protein was able to inhibit Mp growth. Further, airway epithelial cells increased SPLUNC1 expression upon Mp infection. However, the mechanisms underlying SPLUNC1 regulation remain unknown. In the current study, we investigated if SPLUNC1 production following Mp infection is regulated through Toll-like receptor 2 (TLR2) signaling.

Methods

Airway epithelial cell cultures were utilized to reveal the contribution of TLR2 signaling including NF-κB to SPLUNC1 production upon bacterial infection and TLR2 agonist stimulation.

Results

Mp and TLR2 agonist Pam3CSK4 increased SPLUNC1 expression in tracheal epithelial cells from wild type, but not TLR2^-/- BALB/c mice. RNA interference (short-hairpin RNA) of TLR2 in normal human bronchial epithelial cells under air-liquid interface cultures significantly reduced SPLUNC1 levels in Mp-infected or Pam3CSK4-treated cells. Inhibition and activation of NF-κB pathway decreased and increased SPLUNC1 production in airway epithelial cells, respectively.

Conclusions

Our data for the first time suggest that airway epithelial TLR2 signaling is pivotal in mycoplasma-induced SPLUNC1 production, thus improving our understanding of the aberrant SPLUNC1 expression in airways of patients suffering from chronic lung diseases with bacterial infections.

Increased Survivorship and Altered Cytokine Profile from Treatment of Influenza A H1N1-Infected Mice with Ekybion: A Drug Complex of Natural Extracts and Inorganic Compounds

Ekybion is a drug complex of 16 natural extracts and inorganic compounds designed to treat a variety of respiratory pathogens of bacterial and viral origin. It is licensed throughout Europe for the treatment of respiratory tract infections from equine parainfluenza type 3 and equine herpes virus type 1 in equine stables. The purpose of this paper was to test the efficacy of Ekybion on a well-developed animal model of influenza A infection and determine a mode of action. Experiments were performed with Balb/c mice infected with a lethal dose of influenza A/PR/8/34 H1N1 virus and treated with nebulized Ekybion every 8 h in a time-dependant or dose-dependant fashion. These experiments showed that mice treated prior to infection with Ekybion had a higher survival rates (~46%) compared with untreated animals (~0%). Paradoxically, these mice showed no significant difference in lung virus titer or weight loss. There was, however, a decrease in the level of GM-CSF, IL-6, and G-CSF cytokines in the lungs of Ekybion-treated, infected mice. It is possible that decreases in proinflammatory cytokines may have contributed to increased survivorship in Ekybion-treated influenza-infected mice.

Botanicals in dermatology: an evidence-based review

Botanical extracts and single compounds are increasingly used in cosmetics but also in over-the-counter drugs and food supplements. The focus of the present review is on controlled clinical trials with botanicals in the treatment of acne, inflammatory skin diseases, skin infections, UV-induced skin damage, skin cancer, alopecia, vitiligo, and wounds. Studies with botanical cosmetics and drugs are discussed, as well as studies with botanical food supplements. Experimental research on botanicals was considered to a limited extent when it seemed promising for clinical use in the near future. In acne therapy, Mahonia, tea tree oil, and Saccharomyces may have the potential to become standard treatments. Mahonia, Hypericum, Glycyrrhiza and some traditional Chinese medicines appear promising for atopic dermatitis. Some plant-derived substances like dithranol and methoxsalen (8-methoxypsoralen) [in combination with UVA] are already accepted as standard treatments in psoriasis; Mahonia and Capsicum (capsaicin) are the next candidates suggested by present evidence. Oral administration and topical application of antioxidant plant extracts (green and black tea, carotenoids, coffee, and many flavonoids from fruits and vegetables) can protect skin from UV-induced erythema, early aging, and irradiation-induced cancer. Hair loss and vitiligo are also traditional fields of application for botanicals. According to the number and quality of clinical trials with botanicals, the best evidence exists for the treatment of inflammatory skin diseases, i.e. atopic dermatitis and psoriasis. However, many more controlled clinical studies are needed to determine the efficacy and risks of plant-derived products in dermatology. Safety aspects, especially related to sensitization and photodermatitis, have to be taken into account. Therefore, clinicians should not only be informed of the beneficial effects but also the specific adverse effects of botanicals used for dermatologic disorders and cosmetic purposes.

Betulinic acid isolated from Bacopa monniera (L.) Wettst suppresses lipopolysaccharide stimulated interleukin-6 production through modulation of nuclear factor-kappaB in peripheral blood mononuclear cells

The purpose of this study was to investigate the anti-inflammatory function and mechanism(s) of action of an active component-betulinic acid isolated from Bacopa monniera. Betulinic acid, a pentacyclic triterpenoid markedly suppressed lipopolysaccharide (LPS) induced IL-6 production in blood mononuclear cells both in vivo and in vitro. Betulinic acid also prevented LPS induced nuclear translocation of p65 NF-kappaB in hPBMCs. LPS induced nuclear translocation of NF-kappaB and IL-6 production was also abolished by p38 and ERK MAPK inhibitors PD98059 and SB203580. Addition of each of these inhibitors to cell cultures along with betulinic acid caused significant downregulation of IL-6 production and inhibition of p65 NF-kappaB nuclear translocation. The inhibitory effect of both betulinic acid and the inhibitors was higher than that of cells treated with inhibitors alone. These results suggest that betulinic acid inhibited IL-6 production by preventing p65 NF-kappaB nuclear translocation and there is a possibility that this prevention of p65 nuclear translocation may involve p38 and ERK MAPKs as cross talks occur between MAPK and NF-kappaB pathways. This study provides an insight into the probable mechanism(s) underlying the anti-inflammatory and therapeutic properties of betulinic acid.

Interleukin-1beta induces ICAM-1 expression enhancing leukocyte adhesion in human rheumatoid arthritis synovial fibroblasts: involvement of ERK, JNK, AP-1, and NF-kappaB

Interleukin-1beta (IL-1beta) has been shown to induce the expression of adhesion molecules on various cell types and contributes to inflammatory responses. However, the molecular mechanisms by which IL-1beta induced intercellular adhesion molecule (ICAM)-1 expression remain unclear in human rheumatoid arthritis synovial fibroblasts (RASFs). Here, we demonstrated that IL-1beta induces ICAM-1 gene expression via the de novo protein synthesis through transcription and translation, which is attenuated by pretreatment with actinomycin D and cycloheximide, respectively. IL-1beta-induced ICAM-1 expression, extracellular signal-regulated kinase (ERK) and c-Jun-N-terminal kinase (JNK) phosphorylation, AP-1 activation, and nuclear factor-kappaB (NF-kappaB) p65 translocation were attenuated by the inhibitors of MEK1/2 (U0126), JNK (SP600125), AP-1 (tanshinone IIA), and NF-kappaB (helenalin) or transfection with respective short hairpin RNA plasmids. Moreover, IL-1beta-stimulated NF-kappaB p65 translocation was blocked by helenalin, but not by U0126 or SP600125, revealing that MAPKs and NF-kappaB pathways were independent on these responses. IL-1beta-stimulated AP-1 activation was blocked by U0126 or SP600125, revealing that ERK and JNK linked to AP-1 on these responses. IL-1beta-stimulated ICAM-1 gene expression was attenuated by pretreatment with U0126, SP600125, tanshinone IIA, or helenalin, revealed by ICAM-1 promoter assay and real-time RT-PCR analysis. Finally, up-regulation of ICAM-1 enhanced the adhesion of leukocytes to RASFs exposed to IL-1beta. These results suggest that in human RASFs, activation of ERK, JNK, AP-1, and NF-kappaB are essential for IL-1beta-induced ICAM-1 expression and leukocyte adhesion.

The biochemical basis for the anti-inflammatory and cytoprotective actions of ethyl pyruvate and related compounds

Pyruvate is an important metabolic intermediate, and also is an effective scavenger of hydrogen peroxide and other reactive oxygen species (ROS). Pharmacological administration of pyruvate has been shown to improve organ function in animal models of oxidant-mediated cellular injury. However, pyruvate is relatively unstable in aqueous solutions, which could limit the therapeutic potential of this compound. Ethyl pyruvate (EP), a simple derivative of pyruvic acid, is also an ROS scavenger, but seems to exert pharmacological effects, such as suppression of inflammation, which are at least quantitatively different and in some instances are qualitatively distinct from those exerted by pyruvate anion. Treatment with EP has been shown to improve survival and/or ameliorate organ dysfunction in a wide variety of pre-clinical models of acute illnesses, such as severe sepsis, acute pancreatitis and stroke. Using other animal models, some studies have demonstrated that more prolonged treatment with EP can ameliorate inflammatory bowel disease or slow the rate of growth of malignant tumors. In a clinical trial of patients undergoing cardiac surgery, treatment with EP was shown to be safe, but it failed to improve outcome. The true therapeutic potential of EP and related compounds remains to be elucidated. In this review, some of the biochemical mechanisms, which might be responsible for the pharmacological effects of EP, are discussed.

Involvement of MAPKs and NF-kappaB in tumor necrosis factor alpha-induced vascular cell adhesion molecule 1 expression in human rheumatoid arthritis synovial fibroblasts

OBJECTIVE

To investigate the roles of MAPKs and NF-kappaB in tumor necrosis factor alpha (TNFalpha)-induced expression of vascular cell adhesion molecule 1 (VCAM-1) in human rheumatoid arthritis synovial fibroblasts (RASFs).

METHODS

Human RASFs were isolated from synovial tissue obtained from patients with RA who underwent knee or hip surgery. The involvement of MAPKs and NF-kappaB in TNFalpha-induced VCAM-1 expression was investigated using pharmacologic inhibitors and transfection with short hairpin RNA (shRNA) and measured using Western blot, reverse transcriptase-polymerase chain reaction, and gene promoter assay. NF-kappaB translocation was determined by Western blot and immunofluorescence staining. The functional activity of VCAM-1 was evaluated by lymphocyte adhesion assay.

RESULTS

TNFalpha-induced VCAM-1 expression, phosphorylation of p42/p44 MAPK, p38 MAPK, and JNK, and translocation of NF-kappaB were attenuated by the inhibitors of MEK-1/2 (U0126), p38 (SB202190), JNK (SP600125), and NF-kappaB (helenalin) or by transfection with their respective shRNA. TNFalpha-stimulated translocation of NF-kappaB into the nucleus and NF-kappaB promoter activity were blocked by Bay11-7082, but not by U0126, SB202190, or SP600125. VCAM-1 promoter activity was enhanced by TNFalpha in RASFs transfected with VCAM-1-Luc, and this promoter activity was inhibited by Bay11-7082, U0126, SB202190, and SP600125. Moreover, up-regulation of VCAM-1 increased the adhesion of lymphocytes to the RASF monolayer, and this adhesion was attenuated by pretreatment with helenalin, U0126, SP600125, or SB202190 prior to exposure to TNFalpha or by anti-VCAM-1 antibody before the addition of lymphocytes.

CONCLUSION

In RASFs, TNFalpha-induced VCAM-1 expression is mediated through activation of the p42/p44 MAPK, p38 MAPK, JNK, and NF-kappaB pathways. These results provide new insights into the mechanisms underlying cytokine-initiated joint inflammation in RA and may inspire new targeted therapeutic approaches.

Sesquiterpene lactones from Anthemis melanolepis and their antibacterial and cytotoxic activities. Prediction of their pharmacokinetic profile

Nine sesquiterpene lactones, anthemin A (1), 1alpha-hydroxydeacetylirinol-4alpha,5beta-epoxide (2), anthemin C (3), tatridin A (4), 1-epi-tatridin B (5), anthemin B (6), 6-deacetyl-beta-cyclopyrethrosin (7), elegalactone A (8), and 1beta,4alpha,6alpha-trihydroxyeudesm-11-en-8alpha-12-olide (9), were isolated from the aerial parts of A. melanolepis in addition to eight known flavonoids and three phenolic acids. Compounds 1, 3, and 6 are new natural products. The structures of the compounds were deduced by spectroscopic methods. The in vitro antimicrobial potential of the isolated sesquiterpene lactones against four Gram-positive and five Gram-negative bacteria and one fungus was evaluated using the microdilution method, and their in vitro cytotoxic activity was determined against a panel of human tumor cell lines. Furthermore, the pharmacokinetic profile of the sesquiterpene lactones was investigated using computational methods.

Surface plasmon resonance analysis of nuclear factor-kappaB protein interactions with the sesquiterpene lactone helenalin

Sesquiterpene lactones such as helenalin have generally been considered as highly promising compounds for the treatment of inflammatory disorders. Although sesquiterpene lactones are known to inhibit signaling through transcription factor nuclear factor-kappaB (NF-kappaB), the nature of their molecular targets remains controversial. To characterize the interactions of helenalin with putative target proteins, a surface plasmon resonance-based method was developed and validated to analyze the interactions of helenalin with the NF-kappaB protein p65/RelA, with recombinant IkappaB kinases (IKKs) alpha and beta, and with the intracellular antioxidant glutathione, all immobilized on sensor chips. At pH 7.4, helenalin is interacting with RelA (K(D)=4.8microM), yet it failed to bind either IKKalpha or IKKbeta. When DNA with NF-kappaB binding sites was immobilized on sensor chips, the binding of RelA was inhibited by helenalin with an IC(50) of 5.0microM. At pH 8.0, helenalin was also able to interact with reduced, but not oxidized, glutathione with a K(D) of 24microM, but no significant interaction was observed at pH 7.4. Thus, with this optimized method, we showed that the sesquiterpene lactone helenalin interacts with the NF-kappaB protein RelA but not with IKKalpha or IKKbeta. Moreover, at physiological pH, helenalin does not interact with glutathione to any significant extent.

Suppression of the NF-kB signalling pathway by ergolide, sesquiterpene lactone, in HeLa cells

We have previously reported that ergolide, a sesquiterpene lactone isolated from Inula britannica, suppresses inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression by inhibiting nuclear factor-kB (NF-kB) in RAW 264.7 macrophages. In this study, we show that ergolide suppresses the DNA binding activity of NF-kB and nuclear translocation of NF-kB p65 subunit, leading to the inhibition of NF-kB-dependent gene transcription in 12-O-tetradecanoylphorbol 13-acetate (TPA)-stimulated HeLa cells. We also show that ergolide decreases the degradation and phosphorylation of IkB, an inhibitory protein of NF-kB, and this effect is accompanied by a simultaneous reduction of IkB kinase (IKK) activity. However, ergolide does not inhibit in-vitro IKK activity directly, suggesting the possible involvement of upstream IKK kinases in the regulation of NF-kB activation. Furthermore, ergolide-mediated protein kinase Cα (PKCα) inhibition is involved in reduction of NF-kB inhibition, as demonstrated by the observation that dominant negative PKCα, but not p44/42 MAPK and p38 MAPK, inhibits TPA-stimulated reporter gene expression. Taken together, our results suggest that ergolide suppresses NF-kB activation through the inhibition of PKCα-IKK activity, providing insight for PKCα as a molecular target for anti-inflammatory drugs.

Expression profiling identifies epoxy anthraquinone derivative as a DNA topoisomerase inhibitor

To discover novel drugs for neuroblastoma treatment, we have previously screened a panel of drugs and identified 30 active agents against neuroblastoma cells. Here we performed microarray gene expression analysis to monitor the impact of these agents on a neuroblastoma cell line and used the connectivity map (cMAP) to explore putative mechanism of action of unknown drugs. We first compared the expression profiles of 10 compounds shared in both our dataset and cMAP database and observed the high connectivity scores for 7 of 10 matched drugs regardless of the differences of cell lines utilized. The screen of cMAP for uncharacterized drugs indicated the signature of Epoxy anthraquinone derivative (EAD) matched the profiles of multiple known DNA targeted agents (topoisomerase I/II inhibitors, DNA intercalators, and DNA alkylation agents) as predicted by its structure. Similar result was obtained by querying against our internal NB-cMAP (http://pob.abcc.ncifcrf.gov/cgi-bin/cMAP), a database containing the profiles of 30 active drugs. These results suggest that Epoxy anthraquinone derivative may inhibit neuroblastoma cells by targeting DNA replication inhibition. Experimental data also demonstrate that Epoxy anthraquinone derivative indeed induces DNA double-strand breaks through DNA alkylation and inhibition of topoisomerase activity. Our study indicates that Epoxy anthraquinone derivative may be a novel DNA topoisomerase inhibitor that can be potentially used for treatment of neuroblastoma or other cancer patients.