(-)-Oleocanthal as a Dual c-MET-COX2 Inhibitor for the Control of Lung Cancer.

Lung cancer (LC) represents the topmost mortality-causing cancer in the U.S. LC patients have overall poor survival rate with limited available treatment options. Dysregulation of the mesenchymal epithelial transition factor (c-MET) and cyclooxygenase 2 (COX2) initiates aggressive LC profile in a subset of patients. The Mediterranean extra-virgin olive oil (EVOO)-rich diet already documented to reduce multiple malignancies incidence. (-)-Oleocanthal (OC) is a naturally occurring phenolic secoiridoid exclusively occurring in EVOO and showed documented anti-breast and other cancer activities via targeting c-MET. This study shows the novel ability of OC to suppress LC progression and metastasis through dual targeting of c-MET and COX-2. Western blot analysis and COX enzymatic assay showed significant reduction in the total and activated c-MET levels and inhibition of COX1/2 activity in the lung adenocarcinoma cells A549 and NCI-H322M, in vitro. In addition, OC treatment caused a dose-dependent inhibition of the HGF-induced LC cells migration. Daily oral treatment with 10 mg/kg OC for 8 weeks significantly suppressed the LC A549-Luc progression and prevented metastasis to brain and other organs in a nude mouse tail vein injection model. Further, microarray data of OC-treated lung tumors showed a distinct gene signature that confirmed the dual targeting of c-MET and COX2. Thus, the EVOO-based OC is an effective lead with translational potential for use as a prospective nutraceutical to control LC progression and metastasis.

Discovery and preliminary structure-activity relationship of the marine natural product manzamines as herpes simplex virus type-1 inhibitors.

Herpes simplex virus type-1 (HSV-1) is a member of alpha-herpesviridae family and is known to cause contagious human infections. The marine habitat is a rich source of structurally unique bioactive secondary metabolites. A small library of marine natural product classes 1-10 has been screened to discover a new hit entity active against HSV-1. Manzamine A showed potent activity against HSV-1 via targeting the viral gene ICP0. Manzamine A is a ß-carboline alkaloid isolated from the Indo-Pacific sponge Acanthostrongylophora species. Currently, acyclovir is the drug of choice for HSV-1 infections. Compared with 50 µM acyclovir, manzamine A at 1 µM concentration produced potent repressive effects on viral replication and release of infectious viruses in SIRC cells in recent studies. The potent anti-HSV-1 activity of manzamine A prompted a preliminary structure-activity relationship study by testing targeted manzamines. These included 8-hydroxymanzamine A (11), to test the effect of the C-8 hydroxy substitution at the ß-carboline moiety; manzamine E (12), to assess the importance of substitution at the azacyclooctane ring; and ircinal A (13), to determine whether the ß-carboline ring is required for the activity. Manzamine A was chemically transformed to its salt forms, manzamine A monohydrochloride (14) and manzamine A monotartrate (15), to test whether improving water solubility and hydrophilicity will positively affect the activity. Compounds were tested for activity against HSV-1 using fluorescent microscopy and plaque assay. The results showed the reduced anti-HSV-1 activity of 11, suggesting that C-8 hydroxy substitution might adversely affect the activity. Similarly, manzamines 12 and 13 showed no activity against HSV-1, indicating the preference of the unsubstituted azacylcooctane and ß-carboline rings to the activity. Anti-HSV-1 activity was significantly improved for the manzamine A salts 14 and 15, suggesting that improving the overall water solubility as salt forms can significantly enhance the activity. Manzamines have significant potential for future development as anti-HSV-1 entity.

Subereamolline A as a potent breast cancer migration, invasion and proliferation inhibitor and bioactive dibrominated alkaloids from the Red Sea sponge Pseudoceratina arabica.

A new collection of several Red Sea sponges was investigated for the discovery of potential breast cancer migration inhibitors. Extracts of the Verongid sponges Pseudoceratina arabica and Suberea mollis were selected. Bioassay-directed fractionation of both sponges, using the wound-healing assay, resulted into the isolation of several new and known brominated alkaloids. Active fractions of the sponge Pseudoceratina arabica afforded five new alkaloids, ceratinines A-E (2-6), together with the known alkaloids moloka'iamine (1), hydroxymoloka'iamine (7) and moloka'iakitamide (8). The active fraction of the sponge Suberea mollis afforded the three known alkaloids subereamolline A (9), aerothionin (10) and homoaerothionin (11). Ceratinine B (3) possesses an unprecedented 5,7-dibrominated dihydroindole moiety with an epoxy ring on the side chain of a fully substituted aromatic moiety. Ceratinines D (5) and E (6) possess a terminal formamide moiety at the ethylamine side chain. Subereamolline A (9) potently inhibited the migration and invasion of the highly metastatic human breast cancer cells MDA-MB-231 at the nanomolar doses. Subereamolline A and related brominated alkaloids are novel scaffolds appropriate for further future use for the control of metastatic breast cancer.

Effects of chemically characterized fractions from aerial parts of Echinacea purpurea and E. angustifolia on myelopoiesis in rats.

Echinacea species are used for beneficial effects on immune function, and various prevalent phytochemicals have immunomodulatory effects. Using a commercial E. purpurea (L.) Moench product, we have evaluated the myelopoietic effect on bone marrow of rats treated with various extracts and correlated this with their chemical class composition. Granulocyte/macrophage-colony forming cells (GM-CFCs) from femurs of female Sprague-Dawley rats were assessed at 24 h after 7 daily oral treatments. A 75% ethanolic extract at 50 mg dried weight (derived from 227 mg aerial parts) per kg body weight increased GM-CFCs by 70% but at 100 mg/kg was without effect. Ethanolic extracts from aerial parts of E. angustifolia DC. var. angustifolia and E. purpurea from the USDA North Central Regional Plant Introduction Station increased GM-CFCs by 3- and 2-fold, respectively, at 200 mg/kg (~1400 mg/kg plant material). Extract from another USDA E. angustifolia was inactive. Proton and APT NMR, MS, and TLC indicated alkylamides and caffeic-acid derivatives (CADs) present in ethanolic extracts of both the commercial and USDA-derived material. Cichoric and caftaric acids were prominent in both E. purpurea ethanolic extracts but absent in E. angustifolia. Aqueous extract of the commercial material exhibited polysaccharide and CAD signatures and was without effect on GM-CFCs. A methanol-CHCl3 fraction of commercial source, also inactive, was almost exclusively 1:4 nonanoic: decanoic acids, which were also abundant in commercial ethanolic extract but absent from USDA material. In conclusion, we have demonstrated an ethanolextractable myelostimulatory activity in Echinacea aerial parts that, when obtained from commercial herbal supplements, may be antagonized by medium-chain fatty acids presumably derived from a non-plant additive.

Methods for evaluation of structural and biological properties of antiinvasive natural products.

Prostate cancer is considered the most common cancer form among males in Western countries. Very limited options are available for the treatment of advanced metastatic prostate cancer. More than 50% of today's anticancer drugs are natural products or derived from a natural origin. To discover new entities with potential to treat prostate cancer at androgen-refractory stages, 36 structurally diverse natural products were screened using functional-based assays. The tested compounds were selected broadly from major secondary metabolites of plants, marine invertebrates, and fungi. These diverse entities were prescreened for their antiinvasive ability against prostate cancer cells, PC-3M, using spheroid disaggregation assay. Active representatives including three selected structural classes, a macrolide, a ß-carboline alkaloid, and a phenylmethylene hydantoin (PMH), were then tested for their ability to stabilize junctional complexes and enhance cell-cell adhesion of androgen independent prostate cancer cells. Transepithelial resistance (TER) and paracellular permeability assays were used to elicit the aforementioned properties. These studies led to the emergence of PMHs as a small molecule class from the marine sponge Hemimycale arabica with a unique potential to attenuate CT-stimulated prostate cancer growth, metastasis, paracellular permeability, and enhance TER and cell-cell adhesion of prostate cancer cells. The unique activities of PMHs were validated using several in vitro assays followed by in vivo testing in two mice models. A 3D QSAR was established using SYBYL 8.1-Comparative Molecular Field Analysis (CoMFA) model. This chapter includes the methodology for evaluation of structural and biological properties of new antiinvasive molecules with an exceptional potential to stabilize junctional complexes from diverse natural product sources.

Latrunculin A and its C-17-O-carbamates inhibit prostate tumor cell invasion and HIF-1 activation in breast tumor cells.

The marine-derived macrolides latrunculins A ( 1) and B, from the Red Sea sponge Negombata magnifica, have been found to reversibly bind actin monomers, forming a 1:1 complex with G-actin and disrupting its polymerization. The microfilament protein actin is responsible for several essential functions within the cell such as cytokinesis and cell migration. One of the main binding pharmacophores of 1 to G-actin was identified as the C-17 lactol hydroxyl moiety that binds arginine 210 NH. Latrunculin A-17- O-carbamates 2- 6 were prepared by reaction with the corresponding isocyanates. Latrunculin A ( 1) and carbamates 4- 6 displayed potent anti-invasive activity against the human highly metastatic human prostate cancer PC-3M cells in a Matrigel assay at a concentration range of 50 nM to 1 microM. Latrunculin A ( 1, 500 nM) decreased the disaggregation and cell migration of PC-3M-CT+ spheroids by 3-fold. Carbamates 4 and 5 were 2.5- and 5-fold more active than 1, respectively, in this assay with less actin binding affinity. Latrunculin A ( 1, IC 50 6.7 microM) and its 17- O-[ N-(benzyl)carbamate ( 6, IC 50 29 microM) suppress hypoxia-induced HIF-1 activation in T47D breast tumor cells.

Semisynthetic studies on the manzamine alkaloids.

Chemical transformation studies were conducted on (-)-8-hydroxymanzamine A ( 1), (-)-manzamine F ( 2), manzamine A ( 3), and (+)-8-hydroxymanzamine A ( 4), isolated from Indo-Pacific Acanthostrongylophora sponges. Thirteen new semisynthetic manzamine derivatives, including four Delta (34,35) manzamines ( 5, 6, 8, and 9) and the unprecedented manzamine derivative 17, are reported. The potent in vitro activities of the obtained semisynthetic manzamines against activated brain microglia and the AIDS opportunistic infection pathogen Mycobacterium tuberculosis are presented.