Sesquiterpene lactones specifically inhibit activation of NF-kappa B by preventing the degradation of I kappa B-alpha and I kappa B-beta

Mapping taste and flavour traits to genetic markers in lettuce Lactuca sativa

Lettuce is the most highly consumed raw leafy vegetable crop eaten worldwide, making it nutritionally important in spite of its comparatively low nutrient density in relation to other vegetables. However, the perception of bitterness caused by high levels of sesquiterpenoid lactones and comparatively low levels of sweet tasting sugars limits palatability. To assess variation in nutritional and taste-related metabolites we assessed 104 members of a Lactuca sativa cv. Salinas x L. serriola (accession UC96US23) mapping population. Plants were grown in three distinct environments, and untargeted NMR and HPLC were used as a rapid chemotyping method, from which 63 unique Quantitative Trait Loci (QTL) were identified. We were able to identify putative regulatory candidate genes underlying the QTL for fructose on linkage group 9, which accounted for up to 36 % of our population variation, and which was stable across all three growing environments; and for 15-p-hydroxyyphenylacetyllactucin-8-sulfate on linkage group 5 which has previously been identified for its low bitterness, while retaining anti-herbivory field effects. We also identified a candidate gene for flavonoid 3',5'- hydroxylase underlying a polyphenol QTL on linkage group 5, and two further candidate genes in sugar biosynthesis on linkage groups 2 and 5. Collectively these candidate genes and their associated markers can inform a route for plant breeders to improve the palatability and nutritional value of lettuce in their breeding programmes.

First Discovery of Cholesterol-Lowering Activity of Parthenolide as NPC1L1 Inhibitor

Elevated cholesterol significantly increases the risk of developing atherosclerosis and coronary heart disease. The key to treating hypercholesterolemia is lowering plasma cholesterol levels. There have been no studies on the cholesterol-lowering potential of parthenolide (PTL), a naturally occurring small molecule from Tanacetum parthenium. Here, we first put forth PTL’s cholesterol-lowering ability to inhibit cellular uptake of cholesterol in a dose-dependent manner. Its performance was on par with the positive control drug, ezetimibe. Niemann–Pick C1 Like-1 (NPC1L1) has been identified as a potential therapeutic target for hypercholesterolemia. The interaction of PTL with NPC1L1 could be explained by the results of molecular docking and filipin staining further reinforces this hypothesis. Furthermore, PTL reduced the expression of NPC1L1 in HepG2 cells in a concentration-dependent manner, which suggests that PTL functions as a potential NPC1L1 inhibitor with therapeutic potential for hypercholesterolemia.

NF-κB: A Druggable Target in Acute Myeloid Leukemia

Acute Myeloid Leukemia (AML) is an aggressive hematological malignancy that relies on highly heterogeneous cytogenetic alterations. Although in the last few years new agents have been developed for AML treatment, the overall survival prospects for AML patients are still gloomy and new therapeutic options are still urgently needed. Constitutive NF-κB activation has been reported in around 40% of AML patients, where it sustains AML cell survival and chemoresistance. Given the central role of NF-κB in AML, targeting the NF-κB pathway represents an attractive strategy to treat AML. This review focuses on current knowledge of NF-κB's roles in AML pathogenesis and summarizes the main therapeutic approaches used to treat NF-κB-driven AML.

ACT001 attenuates microglia-mediated neuroinflammation after traumatic brain injury via inhibiting AKT/NFκB/NLRP3 pathway

Background

Microglia-mediated neuroinflammatory response following traumatic brain injury (TBI) is considered as a vital secondary injury factor, which drives trauma-induced neurodegeneration and is lack of efficient treatment. ACT001, a sesquiterpene lactone derivative, is reportedly involved in alleviation of inflammatory response. However, little is known regarding its function in regulating innate immune response of central nervous system (CNS) after TBI. This study aimed to investigate the role and underlying mechanism of ACT001 in TBI.

Methods

Controlled cortical impact (CCI) models were used to establish model of TBI. Cresyl violet staining, evans blue extravasation, neurobehavioral function assessments, immunofluorescence and transmission electron microscopy were used to evaluate therapeutic effects of ACT001 in vivo. Microglial depletion was induced by administering mice with colony stimulating factor 1 receptor (CSF1R) inhibitor, PLX5622. Cell-cell interaction models were established as co-culture system to simulate TBI conditions in vitro. Cytotoxic effect of ACT001 on cell viability was assessed by cell counting kit-8 and activation of microglia cells were induced by Lipopolysaccharides (LPS). Pro-inflammatory cytokines expression was determined by Real-time PCR and nitric oxide production. Apoptotic cells were detected by TUNEL and flow cytometry assays. Tube formation was performed to evaluate cellular angiogenic ability. ELISA and western blot experiments were used to determine proteins expression. Pull-down assay was used to analyze proteins that bound ACT001.

Results

ACT001 relieved the extent of blood-brain barrier integrity damage and alleviated motor function deficits after TBI via reducing trauma-induced activation of microglia cells. Delayed depletion of microglia with PLX5622 hindered therapeutic effect of ACT001. Furthermore, ACT001 alleviated LPS-induced activation in mouse and rat primary microglia cells. Besides, ACT001 was effective in suppressing LPS-induced pro-inflammatory cytokines production in BV2 cells, resulting in reduction of neuronal apoptosis in HT22 cells and improvement of tube formation in bEnd.3 cells. Mechanism by which ACT001 functioned was related to AKT/NFκB/NLRP3 pathway. ACT001 restrained NFκB nuclear translocation in microglia cells through inhibiting AKT phosphorylation, resulting in decrease of NLRP3 inflammasome activation, and finally down-regulated microglial neuroinflammatory response.

Conclusions

Our study indicated that ACT001 played critical role in microglia-mediated neuroinflammatory response and might be a novel potential chemotherapeutic drug for TBI.

Therapeutic Potential of Certain Terpenoids as Anticancer Agents: A Scoping Review

Cancer is a life-threatening disease and is considered to be among the leading causes of death worldwide. Chemoresistance, severe toxicity, relapse and metastasis are the major obstacles in cancer therapy. Therefore, introducing new therapeutic agents for cancer remains a priority to increase the range of effective treatments. Terpenoids, a large group of secondary metabolites, are derived from plant sources and are composed of several isoprene units. The high diversity of terpenoids has drawn attention to their potential anticancer and pharmacological activities. Some terpenoids exhibit an anticancer effect by triggering various stages of cancer progression, for example, suppressing the early stage of tumorigenesis via induction of cell cycle arrest, inhibiting cancer cell differentiation and activating apoptosis. At the late stage of cancer development, certain terpenoids are able to inhibit angiogenesis and metastasis via modulation of different intracellular signaling pathways. Significant progress in the identification of the mechanism of action and signaling pathways through which terpenoids exert their anticancer effects has been highlighted. Hence, in this review, the anticancer activities of twenty-five terpenoids are discussed in detail. In addition, this review provides insights on the current clinical trials and future directions towards the development of certain terpenoids as potential anticancer agents.

From Monographs to Chromatograms: The Antimicrobial Potential of Inula Helenium L. (Elecampane) Naturalised in Ireland

With antimicrobial resistance rising globally, the exploration of alternative sources of candidate molecules is critical to safeguard effective chemotherapeutics worldwide. Plant natural products are accessible, structurally diverse compounds with antimicrobial potential. The pharmacological applications of plants in medicine can be guided by the attestation of traditional use, as demonstrated in this study. In Irish ethnomedical literature, Inula helenium L. (elecampane) is often indicated for respiratory and dermal ailments. This is the first assessment of antimicrobial sesquiterpene lactones from the roots of elecampane, naturalised in Ireland. Traditional hydro-ethanolic extracts were prepared from multi-origin elecampane roots. A novel clean-up strategy facilitated the bioactivity-guided fractionation of a subset of anti-staphylococcal fractions (the compositions of which were investigated using HPLC-DAD, supported by ¹H NMR). The natural products attributing to the antimicrobial activity, observed in vitro, were identified as alantolactone (1), isoalantolactone (2), igalan (3), and an unseparated mixture of dugesialactone (4) and alloalantolactone (5), as major compounds. The findings suggest that the geographical origin of the plant does not influence the anti-bacterial potency nor the chemical composition of traditional elecampane root. Considering the prevalence of staphylococci-associated infections and associated broad spectrum resistance in Irish hospitals, currently, further research is warranted into the usage of the identified compounds as potential candidates in the control of staphylococcal carriage and infection.

Nanoparticle-Mediated Delivery of Micheliolide Analogs to Eliminate Leukemic Stem Cells in the Bone Marrow

Micheliolide (MCL) is a naturally occurring sesquiterpene lactone that selectively targets leukemic stem cells (LSCs), which persist after conventional chemotherapy for myeloid leukemias, leading to disease relapse. To overcome modest MCL cytotoxicity, analogs with ≈two-threefold greater cytotoxicity against LSCs are synthesized via late-stage chemoenzymatic C-H functionalization. To enhance bone marrow delivery, MCL analogs are entrapped within bone-targeted polymeric nanoparticles (NPs). Robust drug loading capacities of up to 20% (mg drug mg-1 NP) are obtained, with release dominated by analog hydrophobicity. NPs loaded with a hydrolytically stable analog are tested in a leukemic mouse model. Median survival improved by 13% and bone marrow LSCs are decreased 34-fold following NPMCL treatments versus controls. Additionally, selective leukemic cell and LSC cytotoxicity of the treatment versus normal hematopoietic cells is observed. Overall, these studies demonstrate that MCL-based antileukemic agents combined with bone-targeted NPs offer a promising strategy for eradicating LSCs.

Identification of NLRP3 as a covalent target of 1,6-O,O-diacetylbritannilactone against neuroinflammation by quantitative thiol reactivity profiling (QTRP)

Neuroinflammation plays a key etiological role in the progressive neuronal damage of neurodegenerative diseases. Our phenotypic-based screening discovered 1,6-O,O-diacetylbritannilactone (OABL, 1) from Inula britannica exhibited the potential anti-neuroinflammatory activity as well as a favorable blood-brain barrier penetration. 1 and its active derivative Br-OABL (2) with insert of Br at the C-14 position both modulated TLR4/NF-kB/MAPK pathways. However, proteome-wide identification of 1 binding proteins remains unclear. Here, we employed an adapted isoTOP-ABPP, quantitative thiol reactivity profiling (QTRP) approach, to identify and quantify thiol reactivity binding proteins in murine microglia BV-2 cells. We screened out 15 proteins co-targeted by 1 and 2, which are involved in cellular response to oxidative stress and negative regulation NF-κB transcription factor in biological processes. In site-specific profiling, NLRP3 was identified as a covalent target of 1 and 2 for the first time, and the Cys⁴⁸³ of NLRP3 NACHT domain was identified as one active-site of NLRP3 cysteine residues that can be covalently modified by the α-methylene-γ-lactone moiety. Furthermore, NLRP3 was validated to be directly binded by 1 and 2 by cellular thermo shift assay (CETSA) and activity-based protein profiling (ABPP), and NLRP3 functions were also verified by small interfering RNA approach. Notably, OABL treatment (i.p., 20 mg/kg/day) for 21 days reduced inflammation in 5XFAD mice brain. Together, we applied the QTRP to uncover the binding proteins of OABL in BV-2 cells, among which NLRP3 was revealed as a new covalent target of 1 and 2 against neuroinflammation.

Germacranolides from Carpesium divaricatum: Some New Data on Cytotoxic and Anti-Inflammatory Activity

Carpesium divaricatum Sieb. & Zucc., a traditional medicinal plant used as an inflammation-relieving remedy, is a rich source of terpenoids. At least 40 germacrane-type sesquiterpene lactones, representatives of four different structural groups, were isolated from the plant. Cytotoxicity against cancer cells in vitro is the most frequently described biological activity of the compounds. However, little is known about the selectivity of the cytotoxic effect. The anti-inflammatory activity of the germacranolides is also poorly documented. The objective of the present study was to assess the cytotoxic activity of selected C. divaricatum germacranolides-derivatives of 4,5,8,9-tetrahydroxy-3-oxo-germacran-6,12-olide towards cancer and normal cell lines (including cells of different p53 status). Moreover, to assess the anti-inflammatory effect of the compounds, the release of four proinflammatory cytokines/chemokines (IL-1β, IL-8, TNF-α and CCL2) by lipopolysaccharide-stimulated human neutrophils was measured by ELISA. The investigated sesquiterpene lactones demonstrated nonselective activity towards prostate cancer (Du145 and PC3) and normal prostate epithelial cells (PNT2) as well as against melanoma cells (A375 and HTB140) and keratinocytes (HaCaT). Cytotoxic activity against osteosarcoma cells was independent of their p53 status. In sub-cytotoxic concentrations (0.5-2.5 µM) the studied compounds significantly decreased cytokine/chemokine release by lipopolysaccharide-stimulated human leukocytes.

1,10-Seco-Eudesmane sesquiterpenoids as a new type of anti-neuroinflammatory agents by suppressing TLR4/NF-κB/MAPK pathways

Dysregulation of neuroinflammation is a key pathological factor in the progressive neuronal damage of neurodegenerative diseases. An in-house natural products library of 1407 compounds were screened against neuroinflammation in lipopolysaccharide (LPS)-activated microglia cells to identify a novel hit 1,6-O,O-diacetylbritannilactone (OABL) with anti-neuroinflammatory activity. Furthermore, a 1,10-seco-eudesmane sesquiterpenoid library containing 33 compounds was constructed by semisynthesis of a major component 1-O-acetylbritannilactone (ABL) from the traditional Chinese medicinal herb Inula Britannica L. Compound 15 was identified as a promising anti-neuroinflammatory agent by nitrite oxide (NO) production screening. 15 could attenuate tumor necrosis factor-α (TNF-α) and prostaglandin E2 (PGE2) productions, and inhibit the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) at a submicromolar level. Mechanistic study revealed that 15 significantly modulated TLR4/NF-kB and p38 MAPK pathways, and upregulated the anti-oxidant response HO-1. Besides, 15 promoted the conversion of the microglia from M1 to M2 phenotype by increasing levels of arginase-1 and IL-10. The structure-activity relationships (SARs) analysis indicated that the α-methylene-γ-lactone motifs, epoxidation of C5=C10 bond and bromination of C14 were important to the activity. Parallel artificial membrane permeation assay (PAMPA) also demonstrated that 15 and OABL can overcome the blood-brain barrier (BBB). In all, compound 15 is a promising anti-neuroinflammatory lead with potent anti-inflammatory effects via the blockage of TLR4/NF-κB/MAPK pathways, favorable BBB penetration property, and low cytotoxicity.

Sesquiterpene lactones; Damsin and neoambrosin suppress cytokine-mediated inflammation in complete Freund's adjuvant rat model via shutting Akt/ERK1/2/STAT3 signaling

ETHNOPHARMACOLOGIAL RELEVANCE

Although Damsissa (Ambrosia maritima) is traditionally used as anti-inflammatory and diuretic, the biological activity and mechanism of action of its major constituents are to be elucidated.

AIM

to decipher the anti-arthritic potential of damsin (DMS) and neoambrosin (NMS) and to unfold their molecular signaling in complete Freund's adjuvant (CFA)-induced arthritis model.

MATERIALS AND METHODS

the right hind paw was inoculated with CFA (0.1 ml) at day 0 and 7 while treatments were started from the 14^th day and continued for 2 weeks. Rats were randomly assigned into 4 groups; normal group (NRML), CFA-induced arthritis group, CFA-induced arthritis treated with DMS and NMS (10 mg/kg/day) as 3^rd and 4^th group; respectively.

RESULTS

Throughout experimental period, treatments ameliorated the increase of paw volume, knee joint diameter and nociception tests as reflected in open field arena. Also, DSM and NMS suppressed phosphorylation of Akt, STAT-3, ERK1/2 which was further mirrored by inactivation of GSK3β and downregulation of MCP-1 together with CCN1 and NF-kβ in hind paw tissue. Concomitantly, inflammation markers; TNF-α, IL-6, -12 were lowered as confirmed microscopically during examination of hind paw tissue.

CONCLUSION

DSM and NMS-induced suppression of NF-kβ subdues clinical features of RA most probably through repression of Akt/ERK1/2/STAT3 pathway. Therefore, DMS and NMS can serve as safe and effective treatment for rheumatoid arthritis, one of the most disabling chronic, inflammatory and painful autoimmune disease.

Implication of Lactucopicrin in Autophagy, Cell Cycle Arrest and Oxidative Stress to Inhibit U87Mg Glioblastoma Cell Growth

In this study, we propose lactucopicrin (LCTP), a natural sesquiterpene lactone from Lactucavirosa, as a molecule able to control the growth of glioblastoma continuous cell line U87Mg. The IC50 of U87Mg against LCTP revealed a strong cytotoxic effect. Daily administration of LCTP showed a dose and time-dependent reduction of GBM cell growth and viability, also confirmed by inhibition of clonogenic potential and mobility of U87Mg cells. LCTP activated autophagy in U87Mg cells and decreased the phosphorylation of proliferative signals pAKT and pERK. LCTP also induced the cell cycle arrest in G2/M phase, confirmed by decrease of CDK2 protein and increase of p53 and p21. LCTP stimulated apoptosis as evidenced by reduction of procaspase 6 and the increase of the cleaved/full-length PARP ratio. The pre-treatment of U87Mg cells with ROS scavenger N-acetylcysteine (NAC), which reversed its cytotoxic effect, showed the involvement of LCTP in oxidative stress. Finally, LCTP strongly enhanced the sensitivity of U87Mg cells to canonical therapy Temozolomide (TMZ) and synergized with this drug. Altogether, the growth inhibition of U87Mg GBM cells induced by LCTP is the result of several synergic mechanisms, which makes LCTP a promising adjuvant therapy for this complex pathology.

Micheliolide Enhances Radiosensitivities of p53-Deficient Non-Small-Cell Lung Cancer via Promoting HIF-1α Degradation

Micheliolide (MCL) has shown promising anti-inflammatory and anti-tumor efficacy. However, whether and how MCL enhances the sensitivity of non-small-cell lung cancer (NSCLC) to radiotherapy are still unknown. In the present paper, we found that MCL exerted a tumor cell killing effect on NSCLC cells in a dose-dependent manner, and MCL strongly sensitized p53-deficient NSCLC cells, but not the cells with wild-type p53 to irradiation (IR). Meanwhile, MCL markedly inhibited the expression of hypoxia-inducible factor-1α (HIF-1α) after IR and hypoxic exposure in H1299 and Calu-1 cells rather than in H460 cells. Consistently, radiation- or hypoxia-induced expression of vascular endothelial growth factor (VEGF) was also significantly inhibited by MCL in H1299 and Calu-1 cells, but not in H460 cells. Therefore, inhibition of the HIF-1α pathway might, at least in part, contribute to the radiosensitizing effect of MCL. Further study showed that MCL could accelerate the degradation of HIF-1α through the ubiquitin-proteosome system. In addition, the transfection of wild-type p53 into p53-null cells (H1299) attenuated the effect of MCL on inhibiting HIF-1α expression. These results suggest MCL effectively sensitizes p53-deficient NSCLC cells to IR in a manner of inhibiting the HIF-1α pathway via promoting HIF-1α degradation, and p53 played a negative role in MCL-induced HIF-1α degradation.

Advances in chemistry and bioactivity of parthenolide

(−)-Parthenolide is a germacrane sesquiterpene lactone, available in ample amounts from the traditional medical plant feverfew (Tanacetum parthenium).

Amphiphilic irinotecan–melampomagnolide B conjugate nanoparticles for cancer chemotherapy

Melampomagnolide B (MMB) is a natural sesquiterpene lactone product structurally related to parthenolide (PTL). Although MMB has been widely used to treat various types of cancers, such as glioma, leukemia and colon cancer, the effective delivery of MMB to cancer cells remains a challenge. An amphiphilic drug–drug conjugate (ADDC) strategy has been proposed and developed as a promising drug self-delivery system for cancer therapy because of its simple preparation, carrier-free nature, and high therapeutic activity. Herein, we present a new ADDC, which is synthesized by linking the hydrophilic anticancer drug irinotecan (Ir) and the hydrophobic anticancer drug MMB through a carbonate bond. The obtained amphiphilic irinotecan–melampomagnolide B conjugate (Ir–C–MMB) can self-assemble in water into stable nanoparticles with an average diameter of around 122.1 nm. After cellular uptake, the carbonate bond between the hydrophilic drug and hydrophobic drug can be cleaved to release free Ir and MMB under acidic conditions, which exhibit a synergistic effect in tumor cells. MTT results reveal that the Ir–C–MMB nanoparticles can effectively inhibit proliferation of cancer cells. The apoptosis data indicate that the apoptosis rate of cells treated with Ir–C–MMB nanoparticles is about 50% within 24 h, which is much higher than that of free Ir or MMB. Our results suggest that this ADDC strategy could be used as a drug delivery platform for MMB and its derivatives, and that it offers effective synergistic therapeutic efficacy.

Ir–C–MMB nanoparticles can be easily fabricated using an ADDC strategy, and used as a MMB drug self-delivery platform for synergistic cancer therapy.

Stereoselective total synthesis of parthenolides indicates target selectivity for tubulin carboxypeptidase activity

The 2-(silyloxymethyl)allylboration of aldehydes was established to enable stereoselective access to α-(exo)-methylene γ-butyrolactones under mild conditions. Acid-labile functionality and chiral carbonyl compounds are tolerated. Excellent asymmetric induction was observed for β,β'-disubstituted α,β-epoxy aldehydes. These findings led to the enantioselective total synthesis of the sesquiterpene natural product (-)-parthenolide, its unnatural (+)-enantiomer, and diastereoisomers. Among all the isomers tested in cell culture, only (-)-parthenolide showed potent inhibition of microtubule detyrosination in living cells, confirming its exquisite selectivity on tubulin carboxypeptidase activity. On the other hand, the anti-inflammatory activity of the parthenolides was weaker and less selective with regard to compound stereochemistry.

Ambrosin, a potent NF-κβ inhibitor, ameliorates lipopolysaccharide induced memory impairment, comparison to curcumin

Despite its poor bioavailability, curcumin is a promising natural polyphenol targeting NF-κβ. NF-κβ is a target for new therapeutics because it plays a pivotal role in the pathophysiology of Alzheimer disease (AD). In contrast, ambrsoin, a sesquiterpene lactone which is a potent NF-κβ inhibitor, is scarcely studied in AD models. The current work aims to assess the efficacy of ambrosin as a possible remedy for AD. In silico studies showed that bioavailability and BBB permeability could be favorable for ambrosin over curcumin. Memory impairment was induced in mice by single intraperitoneal injection of LPS (0.4 mg/kg). Treated groups received curcumin (100 mg/kg) or ambrosin at doses (5 or 10 mg/kg) for 7 days. Mice in treated groups showed a significant improvement in memory functions during Morris water maze and object recognition tests. Curcumin and ambrosin (10 mg/kg) inhibited the upsurge of NF-κβp65 transcript and protein levels. Consequently, downstream pro-inflammatory and nitrosative mediators were inhibited, namely, TNF-α, IL-1β, COX-2 and iNOS. BACE1 was inhibited, thereby reducing amyloid plaques (Aβ) deposition and eventually reducing inflammation and apoptosis of neurons as revealed by immunohistopathological examination. In conclusion, ambrosin can be repurposed as AD remedy after further pharmacokinetic/pharamacodynamic assessments. It could serve as an additional lead drug for AD therapeutics.

Collateral Sensitivity of Parthenolide via NF-κB and HIF-α Inhibition and Epigenetic Changes in Drug-Resistant Cancer Cell Lines

Parthenolide (PT) is a sesquiterpene lactone isolated from Tanacetum parthenium. In this study, PT showed varying cytotoxic effects against different solid tumor cell lines. HCT116 (p53^+/+) colon carcinoma cells and their parental HCT116 knockout p53 (p53^-/-) cell lines showed a resistance degree of 2.36. On the other hand, wild-type U87.MG cells or cells transfected with a deletion-activated EGFR cDNA (U87.MGΔEGFR) exhibited slight sensitivity toward PT. Multidrug-resistant MDA-MB-231-BCRP cells were even more sensitive toward PT than sensitive MDA-MB-231-pcDNA cells with a resistance degree of 0.07 (collateral sensitivity). To the best of our knowledge, hypersensitivity (collateral sensitivity) in MDA-MB-231-BCRP cell line is reported in this study for the first time. We attempted to identify the mechanism of collateral sensitivity. Firstly, we found that PT bound to IKK preventing IκBα degradation and eventually inhibition of the nuclear factor kappa B (NF-κB) pathway. Down-regulation of hypoxia inducing factor 1-alpha (HIF-1α) in MDA-MB-231-BCRP resistant cells may be a second mechanism, since it is a target gene of NF-κB. Moreover, PT also showed epigenetic effect by inhibition of HDAC activity as shown using both molecular docking and HDAC activity assay. Based on COMPARE and hierarchical cluster analyses, we found gene expression profiles that predicted sensitivity or resistance of 47 tumor cell lines toward PT. Interestingly, pathway analyses of gene expression profiles revealed NF-κB and HIF signaling as top networks of these genes, cellular functions and canonical pathways influencing the activity of PT against tumor cells. In conclusion, PT exerted profound cytotoxic activity against various cancer cell lines mainly against BCRP-overexpressing tumor cells, suggesting PT as novel candidate for cancer treatment.

Parvifoline Derivatives as Tubulin Polymerization Inhibitors

A series of functionalized sesquiterpenoids derived from benzocyclooctene, including natural parvifoline (1), isoparvifoline (3), epoxyparvifoline (5), epoxyisoparvifoline (7), 8,12-oxyparfivoline (9), 8,14-oxyparvifoline (11), and the respective benzoyl derivatives 2, 4, 6, 8, 10, and 12, were prepared and tested for their inhibitory effect on the in vitro α,β-tubulin polymerization process. The structural analysis and characterization of the new compounds 5-7 and 9-12 were achieved by 1D and 2D NMR spectroscopy, mass spectrometry, and X-ray diffraction analysis of 6, 7, and 9. Preparation of 9 and 12 involved molecular rearrangements of the epoxide group with transannular 1,5-hydride shifts. At 10 μM compounds 1, 5, and 8 inhibited the polymerization of the α,β-tubulin heterodimer by 24%, 49%, and 90% as compared to colchicine. These compounds were subjected to docking analysis that supported their interactions in a colchicine binding site located in the α-tubulin subunit, in the pocket formed by Phe296, Pro298, Pro307, His309, Tyr312, Lys338, Thr340, Ile341, and Gln342. Competitive inhibition assays with colchicine were also performed for the three compounds, which supported their binding at the colchicine secondary site in α-tubulin. Also, evaluations of their cytotoxicity on MCF7 breast carcinoma, HeLa cervix carcinoma, and HCT 116 colon carcinoma cell lines were carried out and showed that 8 is active against the HeLa and HCT 116 cell lines with IC₅₀ 3.3 ± 0.2 and 5.0 ± 0.5 μM, respectively.

Anti-inflammatory Effects of a Sesquiterpene Lactone Extract from Chicory (Cichorium intybus L.) Roots

A chicory root extract rich in sesquiterpene lactones significantly reduced inflammation in two animal models. In a rat paw edema model, chicory extract at 50 and 100 mg/kg significantly reduced inflammation by 58 and 76%, respectively, 24 h after carrageenan injection. In a mouse collagen induced arthritis model, chicory extract (200 mg/kg) reduced paw edema by 71% while the extract was being administered, and 31% 48 h after extract administration was discontinued. Two possible modes of action were investigated, pro-inflammatory gene expression and nitric oxide production by LPS-elicited macrophages. Chicory root extract down-regulated COX-2, TNF-α, IL1β, and iNOS expression and reduced nitric oxide production in a dose dependant manner. Several compounds were isolated from the chicory extract and tested in vitro to confirm activity. Dihydrolactucopicrin and 8-deoxylactucin showed particularly high nitric oxide inhibitory activity (IC50 = 13 μM for both). Dihydrolactucopicrin also was shown to down-regulate pro-inflammatory gene expression. These data demonstrate that chicory extracts rich in sesquiterpene lactones have potent anti-inflammatory activity with potential therapeutic use.

Cumambrin A prevents OVX-induced osteoporosis via the inhibition of osteoclastogenesis, bone resorption, and RANKL signaling pathways

Being the principal cells responsible for bone resorption and pathologic bone loss, osteoclasts have become the main target for antiresorptive treatment. Cumambrin A is a natural compound isolated from Chrysanthemum indicum L. and belongs to a member of the sesquiterpene lactone family. To date, the therapeutic effect of cumambrin A on osteoporosis and its mechanisms of action are not known. In this study, we found that cumambrin A can significantly inhibit osteoclast formation and bone resorption through the suppression of receptor activator of NF-κB ligand (RANKL)-induced NF-κB and nuclear factor of activated T-cell activity and ERK phosphorylation. Furthermore, cumambrin A inhibits the expression of osteoclast marker genes including cathepsin K, calcitonin receptor, and V-ATPase d2. Using an in vivo ovariectomized mouse model, we showed that cumambrin A protects against estrogen withdrawal-induced bone loss. Collectively, our results reveal that cumambrin A can suppress osteoclast formation, bone resorption, and RANKL-induced signaling pathways, suggesting that cumambrin A is a potential therapeutic agent for the treatment of osteoporosis.-Zhou, L., Liu, Q., Hong, G., Song, F., Zhao, J., Yuan, J., Xu, J., Tan, R. X., Tickner, J., Gu, Q., Xu, J. Cumambrin A prevents OVX-induced osteoporosis via the inhibition of osteoclastogenesis, bone resorption, and RANKL signaling pathways.

Sequential and synchronized hypertonicity-induced activation of Rel-family transcription factors is required for osmoprotection in renal cells

NF-κB and TonEBP belong to the Rel-superfamily of transcription factors. Several specific stimuli, including hypertonicity which is a key factor for renal physiology, are able to activate them. It has been reported that, after hypertonic challenge, NF-κB activity can be modulated by TonEBP, considered as the master regulator of transcriptional activity in the presence of changes in environmental tonicity. In the present work we evaluated whether hypertonicity-induced gene transcription mediated by p65/RelA and TonEBP occurs by an independent action of each transcription factor or by acting together. To do this, we evaluated the expression of their specific target genes and cyclooxygenase-2 (COX-2), a common target of both transcription factors, in the renal epithelial cell line Madin-Darby canine kidney (MDCK) subjected to hypertonic environment. The results herein indicate that hypertonicity activates the Rel-family transcription factors p65/RelA and TonEBP in MDCK cells, and that both are required for hypertonic induction of COX-2 and of their specific target genes. In addition, present data show that p65/RelA modulates TonEBP expression and both colocalize in nuclei of hypertonic cultures of MDCK cells. Thus, a sequential and synchronized action p65/RelA → TonEBP would be necessary for the expression of hypertonicity-induced protective genes.

Chemistry and Biology of Selected Mexican Medicinal Plants

Herbal medicines are an integral element of alternative medical care in Mexico, and the best testimony to their efficacy and cultural value is their persistence in contemporary Mexican marketplaces where the highest percentages of medicinal and aromatic plants are sold. This chapter summarizes current trends in research on medicinal plants in Mexico, with emphasis on work carried out at the authors' laboratories. The most relevant phytochemical and pharmacological profiles of a selected group of plants used widely for treating major national health problems are described.From this contribution, it is evident that in the last five decades a significant amount of research on medicinal plants has been performed by Mexican scientists. Such efforts have led to the publication of many research papers in noted peer-reviewed journals and technical books. The isolation and structural characterization of hundreds of bioactive secondary metabolites have been accomplished, and most importantly, these studies have tended to support the ethnomedical uses of many different species. A multidisciplinary approach for investigating these plants has led to an increased emphasis on areas such as phytopharmacology, phytotoxicology, quality control, regulation, and conservation issues for these valuable resources. The medicinal plants analyzed so far have shown a very broad chemical diversity of their constituents, which have a high potential for exhibiting novel mechanistic effects biologically. The chapter shows also that there is need to conduct additional clinical studies on herbal drugs, in particular because the longstanding traditional evidence for their safety is not always sufficient to assure their rational use. There is also need to move to "omics" approaches for investigating the holistic effect and the influence of groups of phytochemicals on the whole organism. Mexican scientists may be expected to have bright prospects in this regard, which will imbue medicinal plant research with a new dynamism in the future.

Sesquiterpene lactones from Ambrosia arborescens Mill. inhibit pro-inflammatory cytokine expression and modulate NF-κB signaling in human skin cells

BACKGROUND

Ambrosia arborescens has been used in Andean traditional medicine to reduce problems associated with various inflammatory diseases and conditions, although the underlying mechanism is unknown.

HYPOTHESIS/PURPOSE

The sesquiterpene lactones (SLs) coronopilin and damsin, which are major secondary metabolites of A. arborescens, have anti-inflammatory activity by attenuation of IL-6 and MCP-1 expression and inhibition of NF-κB in human dermal fibroblasts (HDFa) and human keratinocytes (HaCaT).

STUDY DESIGN

In order to confirm a high concentration of damsin and coronopilin in the plant material, a quantitative method was developed. The effect of the pure compounds on cytokine and NF-κB expression was examined, as well as their effects on HDFa and HaCaT cell morphology and viability.

METHODS

Coronopilin and damsin were quantified by HPLC-DAD analysis, from EtOAc extracts of the aerial parts of A. arborescens. Cell morphology was investigated by phase-contrast microscopy and cell viability by the MTT assay. IL-6 and MCP-1 cytokine gene expression was assessed by quantitative real-time RT-PCR in LPS stimulated cells. The NF-κB pathway was studied through western blotting of the phosphorylated forms of p65 and p50/p105, as well as the non-phosphorylated IκB. Dexamethasone was used as positive control.

RESULTS

Dry aerial parts contained 12.3  mg/g and 13.4  mg/g of coronopilin and damsin, respectively. Treatment with either compound (1-10 µM) for 24  h attenuated LPS-induced mRNA expression of the pro-inflammatory cytokine IL-6 and the chemokine MCP-1 in HDFa cells. The down-regulation of MCP-1 mRNA induced by coronopilin and damsin was confirmed on the protein level. Damsin reduced phosphorylated p65 and p105 subunits in HDFa cells. Neither coronopilin nor damsin affected HDFa cell morphology and viability within the used concentration range (1-10 µM). Also, in HaCaT cells, treatment with damsin (1-10 µM) for 24  h inhibited the MCP-1 expression, and damsin thereby attenuated cytokine expression both in HDFa and HaCaT cells.

CONCLUSION

We show that coronopilin and damsin from A. arborescens inhibit pro-inflammatory IL-6 and MCP-1 expression in human skin cells via NF-κB inhibition, suggesting that they may be useful for antagonizing inflammatory conditions of the human skin.

Uncovering the pharmacological response of novel sesquiterpene derivatives that differentially alter gene expression and modulate the cell cycle in cancer cells

The present study aimed to assess the pharmacological anticancer profile of three natural and five synthetic sesquiterpenes developed by total chemical synthesis. To this end, their properties at the cellular and molecular level were evaluated in a panel of normal and cancer cell lines. The results obtained by performing cytotoxicity assays and gene expression analysis by reverse transcription-quantitative polymerase chain reaction showed that: i) Among the sesquiterpene derivatives analyzed, VDS58 exhibited a notable anticancer profile within attached (U-87 MG and MCF-7) and suspension (K562 and MEL-745) cancer cell cultures; however, U-87 MG cells were able to recover their proliferation capacity rapidly after 48 h of exposure; ii) gene expression profiling of U-87 MG cells, in contrast to K562 cells, showed a transient induction of cyclin-dependent kinase inhibitor 1A (CDKN1) expression; iii) the expression levels of transforming growth factor β1 (TGFB1) increased after 12 h of exposure of U-87 MG cells to VDS58 and were maintained at this level throughout the treatment period; iv) in K562 cells exposed to VDS58, TGFB1 expression levels were upregulated for 48 h and decrease afterwards; and v) the re-addition of VDS58 in U-87 MG cultures pretreated with VDS58 resulted in a notable increase in the expression of caspases (CASP3 and CASP9), BCL2‑associated agonist of cell death (BAD), cyclin D1, CDK6, CDKN1, MYC proto-oncogene bHLH transcription factor (MYC), TGFB1 and tumor suppressor protein p53. This upregulation persisted only for 24 h for the majority of genes, as afterwards, only the expression of TGFB1 and MYC was maintained at high levels. Through bioinformatic pathway analysis of RNA-Seq data of parental U-87 MG and K562 cells, substantial variation was reported in the expression profiles of the genes involved in the regulation of the cell cycle. This was associated with the differential pharmacological profiles observed in the same cells exposed to VDS58. Overall, the data presented in this study provide novel insights into the molecular mechanisms of action of sesquiterpene derivatives by dysregulating the expression levels of genes associated with the cell cycle of cancer cells.

MMB triazole analogs are potent NF-κB inhibitors and anti-cancer agents against both hematological and solid tumor cells

Triazole derivatives of melampomagnolide B (MMB) have been synthesized via click chemistry methodologies and screened against a panel of 60 human cancer cell lines. Several derivatives showed promising anti-cancer activity, affording growth inhibition (GI₅₀) values in the nanomolar range (GI₅₀ = 0.02-0.99 μM). Lead compound 7h exhibited EC₅₀ values of 400 nM and 700 nM, respectively, against two AML clinical specimens. Compound 7h was significantly more potent than parthenolide as an inhibitor of p65 phosphorylation in both hematological and solid tumor cell lines, indicating its ability to inhibit the NF-κB pathway. In TMD-231 breast cancer cells, treatment with 7h reduced DNA binding activity of NF-κB through inhibition of IKK-β mediated p65 phosphorylation and caused elevation of basal IκBα levels through inhibition of constitutive IκBα turnover and NF-κB activation. Molecular docking and dynamic modeling studies indicated that 7h interacts with the kinase domain of the monomeric IKKβ subunit, leading to inhibition of IKKβ activation, and compromising phosphorylation of downstream targets of the NF-κB pathway; dynamic modeling studies show that this interaction also causes unwinding of the α-helix of the NEMO binding site on IKKβ. Molecular docking studies with 10, a water-soluble analog of 7h, demonstrate that this analog interacts with the dimerization/oligomerization domain of monomeric IKKβ and may inhibit oligomer formation and subsequent autophosphorylation. Sesquiterpene lactones 7h and 10 are considered ideal candidates for potential clinical development.

The BACE1 product sAPPβ induces ER stress and inflammation and impairs insulin signaling

OBJECTIVE

β-secretase/β-site amyloid precursor protein (APP)-cleaving enzyme 1 (BACE1) is a key enzyme involved in Alzheimer's disease that has recently been implicated in insulin-independent glucose uptake in myotubes. However, it is presently unknown whether BACE1 and the product of its activity, soluble APPβ (sAPPβ), contribute to lipid-induced inflammation and insulin resistance in skeletal muscle cells.

MATERIALS/METHODS

Studies were conducted in mouse C2C12 myotubes, skeletal muscle from Bace1^-/-mice and mice treated with sAPPβ and adipose tissue and plasma from obese and type 2 diabetic patients.

RESULTS

We show that BACE1 inhibition or knockdown attenuates palmitate-induced endoplasmic reticulum (ER) stress, inflammation, and insulin resistance and prevents the reduction in Peroxisome Proliferator-Activated Receptor γ Co-activator 1α (PGC-1α) and fatty acid oxidation caused by palmitate in myotubes. The effects of palmitate on ER stress, inflammation, insulin resistance, PGC-1α down-regulation, and fatty acid oxidation were mimicked by soluble APPβ in vitro. BACE1 expression was increased in subcutaneous adipose tissue of obese and type 2 diabetic patients and this was accompanied by a decrease in PGC-1α mRNA levels and by an increase in sAPPβ plasma levels of obese type 2 diabetic patients compared to obese non-diabetic subjects. Acute sAPPβ administration to mice reduced PGC-1α levels and increased inflammation in skeletal muscle and decreased insulin sensitivity.

CONCLUSIONS

Collectively, these findings indicate that the BACE1 product sAPPβ is a key determinant in ER stress, inflammation and insulin resistance in skeletal muscle and gluconeogenesis in liver.

Anticancer activity profiling of parthenolide analogs generated via P450-mediated chemoenzymatic synthesis

The plant-derived sesquiterpene lactone parthenolide (PTL) was recently found to possess promising anticancer activity but elaboration of this natural product scaffold for optimization of its pharmacological properties has proven challenging via available chemical methods. In this work, P450-catalyzed C-H hydroxylation of positions C9 and C14 in PTL was coupled to carbamoylation chemistry to yield a panel of novel carbamate-based PTL analogs ('parthenologs'). These compounds, along with a series of other C9- and C14-functionalized parthenologs obtained via O-H acylation, alkylation, and metal-catalyzed carbene insertion, were profiled for their cytotoxicity against a diverse panel of human cancer cell lines. These studies led to the discovery of several parthenologs with significantly improved anticancer activity (2-14-fold) compared to the parent molecule. Most interestingly, two PTL analogs with high cytotoxicity (LC50∼1-3μM) against T cell leukemia (Jurkat), mantle cell lymphoma (JeKo-1), and adenocarcinoma (HeLa) cells as well as a carbamate derivative with potent activity (LC50=0.6μM) against neuroblastoma cells (SK-N-MC) were obtained. In addition, these analyses resulted in the identification of parthenologs featuring both a broad spectrum and tumor cell-specific anticancer activity profile, thus providing valuable probes for the future investigation of biomolecular targets that can affect cell viability across multiple as well as specific types of human cancers. Altogether, these results highlight the potential of P450-mediated chemoenzymatic C-H functionalization toward tuning and improving the anticancer activity of the natural product parthenolide.

Anti-allergic effects of sesquiterpene lactones from Saussurea costus (Falc.) Lipsch. determined using in vivo and in vitro experiments

ETHNOPHARMACOLOGICAL RELEVANCE

Saussurea costus (Falc.) Lipsch. root has been used in Asian traditional medicine for the treatment of asthma, rheumatism, and other conditions. S. costus extracts were shown to alleviate house dust mite-induced atopic-like dermatitis in Nc/Nga mice; besides, sesquiterpene lactones were isolated from S. costus extracts.

AIMS OF THE STUDY

We aimed to investigate the effects of sesquiterpene lactones (alantolactone, costunolide, and dehydrocostuslactone) in allergic asthma using female Balb/c mice and rat RBL-2H3 mast cells.

MATERIALS AND METHODS

Antigen-induced degranulation was assessed by measuring β-hexosaminidase activity in vitro. In addition, a murine ovalbumin-induced allergic asthma model was used to test the in vivo efficacy of sesquiterpene lactones.

RESULTS

Sesquiterpene lactones inhibited antigen-induced degranulation, wherein dehydrocostuslactone > costunolide > alantolactone in potency. Administration of sesquiterpene lactones decreased the number of immune cells, particularly eosinophils, and reduced the expression and secretion of Th2 cytokines (IL-4 and IL-13) in the bronchoalveolar lavage fluid and lung tissues of mice with ovalbumin-induced allergic asthma. Histological studies showed that sesquiterpene lactones reduced inflammation and mucin production in the lungs. Similar to the in vitro study, dehydrocostuslactone showed the highest potency, followed by costunolide and alantolactone.

CONCLUSION

These findings provide evidence that sesquiterpene lactones might be potential anti-allergic therapeutics.

In Vitro Cytotoxic and Anti-inflammatory Activities of Tanacetum argenteum (Lam.) Willd. subsp. argenteum Extract

Objectives

The objective of this study was to examine the anti-inflammatory and cytotoxic potential of n-hexane, ethyl acetate, and methanolic extracts of Tanacetum argenteum subsp. argenteum.

Materials and Methods

Tanacetum L. is the third largest genus of Asteraceae family and is represented by 60 taxa in Turkish flora. Sesquiterpene lactones and pyrethrins are the main chemical groups of the genus. T. argenteum subsp. argenteum is an endemic taxa that is distributed in the Central and South Anatolia.

Results

In vitro anti-inflammatory activity was assayed using iNOS and NF-κB inhibition tests on RAW264.7 and HeLa cells. The cytotoxic activities were tested against ten cell lines using MTT assays.

Conclusion

As a result, the n-hexane extract was found more active than the positive control parthenolide in iNOS test (IC₅₀: 0.627±0.16 μg/mL) and cytotoxic experiments against PC3 and MPANC-96 cell lines (IC₅₀: 2.85±0.51 μg/mL and 5.35±1.24 μg/mL, respectively).

Hemistepsin A ameliorates acute inflammation in macrophages via inhibition of nuclear factor-κB and activation of nuclear factor erythroid 2-related factor 2

Hemistepsin A (HsA) is a sesquiterpene lactone isolated from Hemistepta lyrata (Bunge) Bunge. We investigated the anti-inflammatory effects of HsA and sought to determine its mechanisms of action in macrophages. HsA pretreatment inhibited nitric oxide production, and reduced the expression of iNOS and COX-2 in Toll-like receptor ligand-stimulated RAW 264.7 cells. Additionally, HsA decreased the secretion of proinflammatory cytokines in lipopolysaccharide (LPS)-stimulated Kupffer cells as well as in RAW 264.7 cells. HsA inhibited phosphorylation of IKKα/β and degradation of IκBα, resulting in decreased nuclear translocation of nuclear factor-κB (NF-κB) and its transcriptional activity. Moreover, HsA phosphorylated nuclear factor erythroid 2-related factor 2 (Nrf2), increased expression levels of antioxidant genes, and attenuated LPS-stimulated H₂O₂ production. Phosphorylation of p38 and c-Jun N-terminal kinase was required for HsA-mediated Nrf2 phosphorylation. In a D-galactosamine/LPS-induced liver injury model, HsA ameliorated D-galactosamine/LPS-induced hepatocyte degeneration and inflammatory cells infiltration. Moreover, immunohistochemical analyses using nitrotyrosine, 4-hydroxynonenal, and cleaved poly (ADP-ribose) polymerase antibodies revealed that HsA protected the liver from oxidative stress. Furthermore, HsA reduced the numbers of proinflammatory cytokine-positive cells in hepatic tissues. Thus, these results suggest HsA may be a promising natural product to manage inflammation-mediated tissue injuries through inhibition of NF-κB and activation of Nrf2.

Parthenolide suppresses hypoxia-inducible factor-1α signaling and hypoxia induced epithelial-mesenchymal transition in colorectal cancer

Activation of hypoxia-inducible factor 1α (HIF‑1α) is frequently observed in solid tumors and it has been associated with various pathophysiological processes, including epithelial‑mesenchymal transition (EMT). Previously, we reported that parthenolide (PT), an inhibitor of nuclear factor-κB (NF-κB), is a promising anticancer agent because it promotes apoptosis of human colorectal cancer (CRC). Here, we investigated a new molecular mechanism by which PT acts on HIF‑1α and hypoxia contributing to EMT by NF‑κB inhibition. Cell viability, DNA binding activity, vascular cell tube formation and cell motility were studied after treatment of PT in hypoxic or normoxic condition. Moreover, effects of PT on hypoxia signaling and hypoxia-induced EMT signaling were investigated. We also examined the inhibitory effect of PT on CRC progression in xenografts. We demonstrated that PT markedly inhibits hypoxia dependent HIF‑1α activity and angiogenesis by preventing NF-κB activation. We also report that PT decreases the level of proteins associated with glucose metabolism, angiogenesis, development and survival that are regulated by HIF‑1α. Furthermore, we verified that PT protects the morphological change from epithelial to mesenchymal state, inhibits matrix metalloproteinase (MMP) enzyme activity and decreases cell motility involved in the -regulation of the hypoxia-induced EMT markers. In addition, PT inhibits growth in CRC xenograft models and regulates NF‑κB, HIF‑1α and EMT specific marker in tissue specimens. Our data demonstrated that PT can inhibit HIF‑1α signaling and hypoxia-induced EMT, suggesting a novel molecular mechanism for HIF‑1α mediated cancer progression and metastasis.

Phytochemicals as potential antidotes for targeting NF-κB in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune destructive arthropathy prevalent among people in the age group of 40-70 years. RA induces severe pain, swelling and stiffness of joints resulting in bone damage. RA leads to reduced life expectancy when left untreated. RA is characterized by synovial hyperplasia, infiltration of inflammatory cells resulting in formation of pannus. Synovial hyperplasia is mediated by proinflammatory cytokines, notably IL-1 and TNF-α. NF-κB is a predominant transcription factor in amplifying the inflammatory response. The translocation of activated NF-κB into the nucleus triggers the transcription of several genes that induce proinflammatory cytokine production. The inhibition of NF-κB translocation aids blocking the activation of proinflammatory cascades. The quest for more effective and side-effect free treatment for RA unveiled phytochemicals as efficacious and promising. Phytochemicals have been a source of therapeutic substances for many ailments from ancient times. Their therapeutic ability helps in developing potent and safe drugs targeting immune inflammatory diseases driven by NF-κB including RA. This review highlights the importance of NF-κB inflammatory cascade in RA so as to elucidate the crucial role of phytochemicals that inhibit the activity of NF-κB.

Succinamide derivatives of melampomagnolide B and their anti-cancer activities

A series of succinamide derivatives of melampomagnolide B have been synthesized by coupling MMB monosuccinate (2) with various heterocyclic amines to afford compounds 3a-3l. MMB monosuccinate was also reacted with terminal diaminoalkanes to afford dimeric succinamido analogs of MMB (4a-4h). These succinamide analogs of MMB were evaluated for their anti-cancer activity against a panel of sixty human cancer cell lines. Analogs 3d-3i and dimers 4f-4g exhibited promising anti-cancer activity with GI50 values ranging from 0.28 to 33.5µM against most of the cell lines in the panel. The dimeric analogs 4f and 4g were identified as lead compounds with GI50 values in the nanomolar range (GI50=280-980nM) against several cell lines in the panel; i.e. leukemia cell lines CCRF-CEM, HL-60(TB), K-562, MOLT-4, RPMI-8226 and SR; and solid tumor cell lines NCI-H522 (non-small cell lung cancer), SW-620 and HCT-116 (colon cancer), LOX IMVI (melanoma), RXF 393 (renal cancer), and MCF7, BT-549 and MDA-MB-468 (breast cancer). Succinamide analogs 3a, 3c-3l and 4b-4h were also evaluated for their apoptotic activity against M9-ENL1 acute myelogenous leukemia cells; compounds 3h-3j and 4g were equipotent with parthenolide, exhibiting LC50 values in the range 4.1-8.1μM. Molecular docking studies indicate that these molecules interact covalently with the highly conserved Cys-46 residue of the N-terminal lobe (1-109) of human IKKβ to inhibit the NFκB transcription factor complex, resulting in down-regulation of anti-apoptotic genes under NFκB control.

Biomedical Properties and Origins of Sesquiterpene Lactones, with a Focus on Dehydroleucodine

Dehydroleucodine, a sesquiterpene lactone, belongs to the terpenoid class of secondary metabolites. Dehydroleucodine and other Artemisia-derived phytochemicals evolved numerous biodefenses that were first co-opted for human pharmacological use by traditional cultures in the Middle East, Asia, Europe and the Americas. Later, these phytochemicals were modified through the use of medicinal chemical techniques to increase their potency. All sesquiterpene lactones contain an α-methylene-γ-lactone group, which confers thiol reactivity, which is responsible, in part, for their therapeutic effects. A wide range of therapeutic uses of sequiterpene lactones has been found, including anti-adipogenic, cytoprotective, anti-microbial, anti-viral, anti-fungal, anti-malarial and, anti-migraine effects. Dehydroleucodine significantly inhibits differentiation of murine preadipocytes and also significantly decreases the accumulation of lipid content by a dramatic down regulation of adipogenic-specific transcriptional factors PPARγ and C-EBPα. Dehydroleucodine also inhibits secretion of matrix metalloprotease-2 (MMP-2), which is a known protease involved in migration and invasion of B16 cells. In addition to these anti-adipogenic and anti-cancer effects, dehydroleucodine effectively neutralizes several bacterial species, including Bacillus cereus, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Helicobacter pylori, methicillin resistant Staphylococcus aueus (MRSA) and S. epidermis (MRSE). The compound also inhibits the growth and secretion of several toxins of Pseudomonas aeruginosa, possesses gastro-protective qualities and possesses anti-parasitic properties against Trypanosoma cruzi, responsible for Chagas disease. Other sesquiterpene lactones, such as parthenolide, costunolide, and helanin, also possess significant therapeutic utility.

Indole carboxylic acid esters of melampomagnolide B are potent anticancer agents against both hematological and solid tumor cells

A series of novel, heteroaryl carboxylic acid conjugates of the sesquiterpene melampomagnolide-B (MMB, 3) has been evaluated as antitumor agents against an NCI panel of 64 human hematopoetic and solid tumor cell lines. The indole-3-acrylic acid conjugate 7j and the indole-3-carboxylic acid conjugate 7k were found to be the most potent analogs in the series. Compounds 7j and 7k exhibited remarkable growth inhibition, with GI₅₀ values in the range 0.03-0.30 μM and 0.04-0.28 μM, respectively, against the cell lines in the leukemia sub-panel, and GI₅₀ values of 0.05-0.40 μM and 0.04-0.61 μM, respectively, against 90% of the solid tumor cell lines in the NCI panel. Compound 7a was particularly effective against the sub-panel of breast cancer cell lines with GI₅₀ values in the range <0.01-0.30 μM. Compounds 7j, 7a and its water soluble analog 7p also exhibited potent anticancer activity against rat 9L-SF gliosarcoma cells in culture. Compound 7j was the most potent compound in the series in the M9-ENL1 AML cell assay with a lethal dose concentration EC₅₀ value of 720 nM, and exhibited the greatest cytotoxicity against a collection of primary AML stem cell specimens, which included a specimen that was unresponsive to PTL, affording EC₅₀ values in the range 0.33-1.0 μM in three out of four specimens. The results from this study provide further evidence that analogs of the sesquiterpene MMB can be designed to afford molecules with significantly improved anticancer activity. Thus, both 7j and 7k are considered potential lead molecules in the search for new anticancer agents that can be used as treatments for both hematopoetic and solid tumors.

Parthenolide promotes apoptotic cell death and inhibits the migration and invasion of SW620 cells

Background/Aims

Parthenolide (PT), a principle component derived from feverfew (Tanacetum parthenium), is a promising anticancer agent and has been shown to promote apoptotic cell death in various cancer cells. In this study, we focused on its functional role in apoptosis, migration, and invasion of human colorectal cancer (CRC) cells.

Methods

SW620 cells were employed as representative human CRC cells. We performed the MTT assay and cell cycle analysis to measure apoptotic cell death. The wound healing, Transwell migration, and Matrigel invasion assays were performed to investigate the effect of PT on cell migration/invasion. Western blotting was used to establish the signaling pathway of apoptosis and cell migration/invasion.

Results

PT exerts antiproliferative effect and induces apoptotic cell death of SW620 cells. In addition, PT prevents cell migration and invasion in a dose-dependent manner. Moreover, PT markedly suppressed migration/invasion-related protein expression, including E-cadherin, β-catenin, vimentin, Snail, cyclooxygenase-2, matrix metalloproteinase-2 (MMP-2), and MMP-9 in SW620 cells. PT also inhibited the expression of antiapoptotic proteins (Bcl-2 and Bcl-xL) and activated apoptosis terminal factor (caspase-3) in a dose-dependent manner.

Conclusions

Our results suggest that PT is a potential novel therapeutic agent for aggressive CRC treatment.

Torilin Inhibits Inflammation by Limiting TAK1-Mediated MAP Kinase and NF-κB Activation

Torilin, a sesquiterpene isolated from the fruits of Torilis japonica, has shown antimicrobial, anticancer, and anti-inflammatory properties. However, data on the mechanism of torilin action against inflammation is limited. This study aimed at determining the anti-inflammatory property of torilin in LPS-induced inflammation using in vitro model of inflammation. We examined torilin's effect on expression levels of inflammatory mediators and cytokines in LPS-stimulated RAW 264.7 macrophages. The involvement of NF-kB and AP-1, MAP kinases, and adaptor proteins were assessed. Torilin strongly inhibited LPS-induced NO release, iNOS, PGE₂, COX-2, NF-α, IL-1β, IL-6, and GM-CSF gene and protein expressions. In addition, MAPKs were also suppressed by torilin pretreatment. Involvement of ERK1/2, P38^MAPK, and JNK1/2 was further confirmed by PD98059, SB203580, and SP600125 mediated suppression of iNOS and COX-2 proteins. Furthermore, torilin attenuated NF-kB and AP-1 translocation, DNA binding, and reporter gene transcription. Interestingly, torilin inhibited TAK1 kinase activation with the subsequent suppression of MAPK-mediated JNK, p38, ERK1/2, and AP-1 (ATF-2 and c-jun) activation and IKK-mediated I-κBα degradation, p65/p50 activation, and translocation. Together, the results revealed the suppression of NF-κB and AP-1 regulated inflammatory mediator and cytokine expressions, suggesting the test compound's potential as a candidate anti-inflammatory agent.

Identification of a melampomagnolide B analog as a potential lead molecule for treatment of acute myelogenous leukemia

A series of carbamate derivatives of the antileukemic sesquiterpene melampomagnolide B (MMB) has been synthesized utilizing a 1,2,4-triazole carbamate conjugate of MMB as an intermediate synthon. Five imidazole- and benzimidazole-carbamate analogs of MMB (8a-8e) were prepared and evaluated for anti-leukemic activity against cultured M9 ENL1 AML cells. All the analogs exhibited improved anti-leukemic activity (EC₅₀=0.90-3.93μM) when compared to parthenolide and the parent sesquiterpene, MMB (EC₅₀=7.0μM and 15.5μM, respectively). The imidazole carbamate analog, 8a (EC₅₀=0.9μM), was 16 times more potent than MMB. The comparative bioavailabilities of 8a and MMB were determined in BALB/c mice following oral dosing of these compounds. It has been demonstrated that the absolute plasma bioavailabilities of MMB and 8a were 6.7±0.8%, and 45.5±2%, respectively. These results indicate that, compared to MMB, the PK parameters for 8a display significantly improved bioavailability and exposure after oral administration. Analog 8a is considered to be a potential clinical candidate for treatment of acute myelogenous leukemia.

In vitro antiviral activity of three enantiomeric sesquiterpene lactones from Senecio species against hepatitis B virus

Three enantiomeric sesquiterpene lactones were isolated under the bioguidance of the suppression of hepatitis B virus (HBV) surface antigen (HBsAg) from Senecio species, a widely distributed Chinese medicinal herb traditionally used for the treatment of hepatitis B, dermatosis and inflammation. The anti-HBV activity of the purified compounds was measured; all of them showed suppressive activity on the expression of HBsAg and HBV e antigen (HBeAg) in the HepG2.2.15 cell line. Realtime quantitative PCR analysis showed that the studied compounds decreased the number of infectious virions released, but did not inhibit the intracellular HBV DNA. The results suggest that enantiomeric sesquiterpene lactones may possess the potential to work synergistically with other antiviral compounds for the treatment of HBV infection.

Combined Parthenolide and Balsalazide Have Enhanced Antitumor Efficacy Through Blockade of NF-κB Activation

Balsalazide is a colon-specific prodrug of 5-aminosalicylate that is associated with a reduced risk of colon cancer in patients with ulcerative colitis. Parthenolide, a strong NF-κB inhibitor, has recently been demonstrated to be a promising therapeutic agent, promoting apoptosis of cancer cells. In the current study, the antitumor effect of balsalazide combined with parthenolide in human colorectal cancer cells and colitis-associated colon cancers (CAC) was investigated. The results demonstrate that the combination of balsalazide and parthenolide markedly suppress proliferation, nuclear translocation of NF-κB, IκB-α phosphorylation, NF-κB DNA binding, and expression of NF-κB targets. Apoptosis via NF-κB signaling was confirmed by detecting expression of caspases, p53 and PARP. Moreover, treatment of a CAC murine model with parthenolide and balsalazide together resulted in significant recovery of body weight and improvement in histologic severity. Administration of parthenolide and balsalazide to CAC mice also suppressed carcinogenesis as demonstrated by uptake of 18F-fluoro-2-deoxy-D-glucose (FDG) using micro-PET/CT scans. These results demonstrate that parthenolide potentiates the efficacy of balsalazide through synergistic inhibition of NF-κB activation and the combination of dual agents prevents colon carcinogenesis from chronic inflammation.

IMPLICATIONS

This study represents the first evidence that combination therapy with balsalazide and parthenolide could be a new regimen for colorectal cancer treatment. Mol Cancer Res; 15(2); 141-51. ©2016 AACR.

Sugar-Modified Poly(propylene imine) Dendrimers Stimulate the NF-κB Pathway in a Myeloid Cell Line

Purpose

Fourth-generation poly(propylene imine) dendrimers fully surface-modified by maltose (dense shell, PPI-m DS) were shown to be biocompatible in cellular models, which is important for their application in drug delivery. We decided to verify also their inherent bioactivity, including immunomodulatory activity, for potential clinical applications. We tested their effects on the THP-1 monocytic cell line model of innate immunity effectors.

Methods

To estimate the cytotoxicity of dendrimers the reasazurin assay was performed. The expression level of NF-κB targets: IGFBP3, TNFAIP3 and TNF was determined by quantitative real-time RT-PCR. Measurement of NF-κB p65 translocation from cytoplasm to nucleus was conducted with a high-content screening platform and binding of NF-κB to a consensus DNA probe was determined by electrophoretic mobility shift assay. The cytokine assay was performed to measure protein concentration of TNFalpha and IL-4.

Results

We found that PPI-m DS did not impact THP-1 viability and growth even at high concentrations (up to 100 μM). They also did not induce expression of genes for important signaling pathways: Jak/STAT, Keap1/Nrf2 and ER stress. However, high concentrations of 4th generation PPI-m DS (25–100 μM), but not their 3rd generation counterparts, induced nuclear translocation of p65 NF-κB protein and its DNA-binding activity, leading to NF-κB-dependent increased expression of mRNA for NF-κB targets: IGFBP3, TNFAIP3 and TNF. However, no increase in pro-inflammatory cytokine secretion was detected.

Conclusion

We conclude that maltose-modified PPI dendrimers of specific size could exert a modest immunomodulatory effect, which may be advantageous in clinical applications (e.g. adjuvant effect in anti-cancer vaccines).

Chemoenzymatic synthesis and antileukemic activity of novel C9- and C14-functionalized parthenolide analogs

Parthenolide is a naturally occurring terpene with promising anticancer properties, particularly in the context of acute myeloid leukemia (AML). Optimization of this natural product has been challenged by limited opportunities for the late-stage functionalization of this molecule without affecting the pharmacologically important α-methylene-γ-lactone moiety. Here, we report the further development and application of a chemoenzymatic strategy to afford a series of new analogs of parthenolide functionalized at the aliphatic positions C9 and C14. Several of these compounds were determined to be able to kill leukemia cells and patient-derived primary AML specimens with improved activity compared to parthenolide, exhibiting LC50 values in the low micromolar range. These studies demonstrate that different O-H functionalization chemistries can be applied to elaborate the parthenolide scaffold and that modifications at the C9 or C14 position can effectively enhance the antileukemic properties of this natural product. The C9-functionalized analogs 22a and 25b were identified as the most interesting compounds in terms of antileukemic potency and selectivity toward AML versus healthy blood cells.