Marine algae: A treasure trove of bioactive anti-inflammatory compounds.

This comprehensive review examines the diverse classes of pharmacologically active compounds found in marine algae and their promising anti-inflammatory effects. The review covers various classes of anti-inflammatory compounds sourced from marine algae, including phenolic compounds, flavonoids, terpenoids, caretenoids, alkaloids, phlorotannins, bromophenols, amino acids, peptides, proteins, polysaccharides, and fatty acids. The anti-inflammatory activities of marine algae-derived compounds have been extensively investigated using in vitro and in vivo models, demonstrating their ability to inhibit pro-inflammatory mediators, such as cytokines, chemokines, and enzymes involved in inflammation. Moreover, marine algae-derived compounds have exhibited immunomodulatory properties, regulating immune cell functions and attenuating inflammatory responses. Specific examples of compounds with notable anti-inflammatory activities are highlighted. This review provides valuable insights for researchers in the field of marine anti-inflammatory pharmacology and emphasizes the need for further research to harness the pharmacological benefits of marine algae-derived compounds for the development of effective and safe therapeutic agents.

Antioxidant and anti-Alzheimer activities of Clivia miniata (Lindl) roots, bulbs, and aerial parts: In-vitro and in-silico studies.

Clivia miniata (Lindl) is a member of the family Amaryllidaceae known for its chemically diverse alkaloids with a wide range of biological activities. Many reports revealed a direct role of oxidative stress in the early stage of Alzheimer's disease (AD). Meanwhile, ß-site amyloid precursor protein cleavage enzyme 1 (BACE-1) is a molecular target for the treatment of AD. We aimed to investigate C. miniata root, bulb, and aerial part chemical profiling, antioxidant, BACE-1, and AChE enzyme inhibitory activities. Results showed that the total root had the most potent radical scavenging activity as compared to the total bulb and aerial part, respectively. Ethanol root extract had the most potent BACE-1 inhibitory activity (IC50 = 0.02 ± 0.001 µg/mL) as compared to the bulb and aerial part (IC50 = 0.93 ± 0.13, 1.80 ± 0.24 µg/mL), respectively. Moreover, the total root extract mitigated AChE enzyme activity more than total bulb and aerial fractions with IC50 values of (0.06 ± 0.02, 0.58 ± 0.3, and 1.89 ± 0.42 µg/mL, respectively. Bioassay-guided acid-base fractionation confirmed superior BACE-1 inhibitory activity of the root fractions particularly, methylene chloride and ethyl acetate fractions with (IC50 values of 0.21 ± 0.60 and 0.01 ± 0.001 µg/mL), respectively. UPLC-MS analysis of ethyl acetate and methylene chloride fractions of C. miniata root led to the identification of eight phenolics and thirteen alkaloids, respectively. Molecular docking studies against BACE-1 protein revealed that lycorine di-hexoside, miniatine, and cliviaaline were the most promising hits. Further investigation of anti-AD potential of the aforementioned small molecules is required.

ESI-LC-MS/MS based comparative multivariate metabolomic and biological profiling with dynamic molecular docking of Gmelina arborea Roxb different organs.

A comprehensive study of leaves, flowers, fruits, bark, and seeds' extracts of Gmelina arborea Roxb was performed for first time to investigate their anti-inflammatory, anti-Alzheimer, and antidiabetic activities. A thorough comparative phytochemical investigation of the five organs was performed using Tandem ESI-LC-MS. The biological investigation, further aided by multivariate data analysis and molecular docking proved the highly significant potential of using G.arborea organs' extracts as medicinal agents. Chemometric analysis of the obtained data revealed 4 distinct clusters among different samples of the 5 G.arborea (GA)organs and also confirmed that each organ was chemically distinct from the others, except for fruits and seeds which were closely correlated. Compounds anticipated to be responsible for activity were identified by LC-MS/MS. To clarify the differential chemical biomarkers of G. arborea organs, an orthogonal partial least squares discriminant analysis (OPLS-DA) was constructed. Bark exhibited it's in vitro anti-inflammatory activity through down regulation of COX-1 pro-inflammatory markers while fruits and leaves affected mainly DPP4 the marker for diabetes, and flowers were the most potent against Alzheimer maker acetylcholine (ACE) esterase. The metabolomic profiling of the 5 extracts lead to the identification of 27 compounds in negative ion mode and the differences in chemical composition were correlated to difference in activity. Iridoid glycosides were the major class of identified compounds. Molecular docking proved the different affinities of our metabolite towards different targets. Gmelina arborea Roxb. is a very important plant both economically and medicinally.

Comparative anti-herpes simplex virus type 1 and chemical profiling of Thymus capitatus and Artemisia herba-alba collected from North Africa.

Herpes simplex virus (HSV) can infect millions of people worldwide causing mild to life-threating infections. The current study demonstrates the first comparative anti-HSV type 1 activity and phytochemical investigation of Artemisia herba-alba and Thymus capitatus collected from Egypt and Libya. Liquid chromatography/mass spectrometry (LC/MS) analysis allowed the identification of 56 and 38 compounds in the Egyptian and Libyan Artemisia herba-alba ethanolic extracts, respectively, in addition to 46 and 50 compounds in the Egyptian and Libyan Thymus capitatus ethanolic extracts, respectively. Gas chromatography/mass spectrometry (GC/MS) analysis of their corresponding essential oils revealed the presence of 15, 17, 17 and 8 compounds in Egyptian and Libyan Artemisia herba-alba and Thymus capitatus, respectively. The major chemical classes of the identified compounds were phenolic acids, flavonoids and oxygenated monoterpenes. Evaluation of the anti-HSV1 activities of the studied extracts showed that the Egyptian Thymus capitatus ethanolic extracts were the most potent extract with more than 200-fold reduction in the viral PFU.

Comprehensive metabolomics unveil the discriminatory metabolites of some Mediterranean Sea marine algae in relation to their cytotoxic activities.

Marine algae have served as a treasure trove of structurally variable and biologically active metabolites. The present study emphasizes on UPLC-MS metabolites fingerprinting for the first systematic broad scale metabolites characterization of three different phyla of marine seaweeds; Ulva fasciata, Pterocladia capillacea and Sargassum hornschuchii along with Spirulina platensis harvested from the Mediterranean Sea. A total of 85 metabolites belonging to various classes including mostly fatty acids and their derivatives, terpenoids, amino acids and dipeptides with considerable amounts of polyphenolic compounds. OPLS-DA model offered a better overview of phylum-based discrimination rapidly uncovering the compositional heterogeneity in metabolite profiles of algae extracts. An OPLS model was constructed using the cytotoxic activities against PC3 and MDA-MB-231 tumor cells to succinctly screen cytotoxic discriminatory metabolites among the tested algae species. The coefficient plot revealed that unsaturated fatty acids as stearidonic acid and linolenic acid, terpenoids namely as rosmanol, campestanol, dipeptides primarily glutamylglycine, glycyltyrosine along with polyphenolic compounds being abundantly present in S. platensis and U. fasciata samples with relatively marked cytotoxic potential might be the significant contributors synergistically meditating their anti-proliferative activity against PC3 and MDA-MB-231 tumor cells. Such results serve as baseline for understanding the chemistry of these species and performing strict correlation between metabolite and activity where a lack of information in this regard is observed.

Integrated in silico - in vitro strategy for the discovery of potential xanthine oxidase inhibitors from Egyptian propolis and their synergistic effect with allopurinol and febuxostat.

Xanthine oxidase (XO) has been well-recognized as a validated target for the treatment of hyperuricemia and gout. Currently, there are two drugs in clinical use that shut down XO overactivity, allopurinol and febuxostat; however, detrimental side effects restrict their applications. Propolis is a unique natural adhesive biomass of structurally variable and biologically active metabolites that exert remarkable health benefits. Moreover, combination drug therapy has become a promising pharmacotherapeutic strategy directed for reformulating existing drugs into new combination entities with potentiating therapeutic impacts. In this study, computer-aided molecular docking and MD simulations accompanied by biochemical testing were used for mining novel pharmacologically active chemical entities from Egyptian propolis to combat hyperuricemia. Further, with a view to decrease the potential toxicity of synthetic drugs and enhance efficacy, propolis hits were subjected to combination analysis with each of allopurinol and febuxostat. More specifically, Glide docking was utilized for a structure-based virtual screening of in-house datasets comprising various Egyptian propolis metabolites. Rosmarinic acid, luteolin, techtochrysin and isoferulic acid were the most promising virtual hits. In vitro XO inhibitory assays demonstrated the ability of these hits to significantly inhibit XO in a dose-dependent manner. Molecular docking and MD simulations revealed a cooperative binding mode between the discovered hits and standard XO inhibitors within the active site. Subsequently, the most promising hits were tested in a fixed-ratio combination setting with allopurinol and febuxostat separately to assess their combined effects on XO catalytic inhibition. The binary combination of each techtochrysin and rosmarinic acid with febuxostat displayed maximal synergy at lower effect levels. In contrast, individually, techtochrysin and rosmarinic acid with allopurinol cooperated synergistically at high dose levels. Taken together, the suggested strategy seems imperative to ensure a steady supply of new therapeutic options sourced from Egyptian propolis to regress the development of hyperuricemia.

Pseurotin A as a novel suppressor of hormone dependent breast cancer progression and recurrence by inhibiting PCSK9 secretion and interaction with LDL receptor.

Hypercholesterolemia has been documented to drive hormone-dependent breast cancer (BC) progression and resistance to hormonal therapy. Proprotein convertase subtilisin/kexin type-9 (PCSK9) regulates cholesterol metabolism through binding to LDL receptor (LDLR) and targeting the receptor for lysosomal degradation. Inhibition of PCSK9 is an established strategy to treat hypercholesterolemia. Pseurotin A (PS) is a unique spiro-heterocyclic γ-lactam alkaloid isolated from the fungus Aspergillus fumigatus. Preliminary studies indicated that PS lowered PCSK9 secretion in cultured HepG2 hepatocellular carcinoma cells, with an IC50 value of 1.20 µM. Docking studies suggested the ability of PS to bind at the PCSK9 narrow interface pocket that accommodates LDLR. Surface plasmon resonance (SPR) showed PS ability to inhibit the PCSK9-LDLR interaction at a concentration range of 10-150 µM. PS showed in vitro dose-dependent reduction of PCSK9, along with increased LDLR levels in hormone-dependent BT-474 and T47D breast cancer (BC) cell lines. In vivo, daily oral 10 mg/kg PS suppressed the progression of the hormone-dependent BT-474 BC cells in orthotopic nude mouse xenograft model. Immunohistochemistry (IHC) investigation of BT-474 breast tumor tissue proved the PS ability to reduce PCSK9 expression. PS also effectively suppressed BT-474 BC cells locoregional recurrence after primary tumor surgical excision. Western blot analysis showed decreased PCSK9 expression in liver tissues of PS-treated mice compared to vehicle-treated control group. PS treatment significantly reduced PCSK9 expression and normalized LDLR levels in collected primary and recurrent breast tumors at the study end. PS-treated mice showed reduced plasma cholesterol and 17ß-estradiol levels. Inhibition of tumor recurrence was associated with significant reductions in plasma level of the human BC recurrence marker CA 15-3 in treated mice at the study end. Histopathological examination of various PS-treated mice organs indicated lack of metastatic tumor cells and any pathological changes. The results of this study provide the first evidence for the suppression of the hormone-dependent breast tumor progression and recurrence by targeting the PCSK9-LDLR axis. PS is a novel first-in-class PCSK9-targeting lead appropriate for the use to control hormone-dependent BC progression and recurrence.

(-)-Oleocanthal Combined with Lapatinib Treatment Synergized against HER-2 Positive Breast Cancer In Vitro and In Vivo.

Dysregulation of epidermal growth factor receptor (EGFR)/human epidermal growth factor-2 (HER2) family is a hallmark of aggressive breast cancer. Small-molecule tyrosine kinase inhibitors are among the most effective cancer targeted treatments. (-)-Oleocanthal (OC) is a naturally occurring phenolic secoiridoid lead from extra-virgin olive oil with documented anti-cancer activities via targeting mesenchymal epithelial transition factor (c-Met). Dysregulation of c-Met promotes aggressiveness to breast cancer-targeted therapies. Lapatinib (LP) is an FDA-approved dual EGFR/HER2 inhibitor for HER2-amplified breast cancer. HER2-Positive tumor cells can escape targeted therapies like LP effects by overexpressing c-Met. Combined OC-LP treatment is hypothesized to be mechanistically synergistic against HER2-overexpressing breast cancer. Combined sub-effective treatments of OC-LP resulted in synergistic anti-proliferative effects against the HER2-positive BT-474 and SK-BR-3 breast cancer cell lines, compared to OC or LP monotherapy. Antibody array and Western blot analysis showed that combined OC-LP treatment significantly inhibited EGFR, HER2, and c-Met receptor activation, as well as multiple downstream signaling proteins, compared to individual OC or LP treatment. OC-LP Combination significantly inhibited invasion and migration of breast cancer cells through reduced activation of focal adhesion kinase (FAK) and paxillin. Combined treatment of OC-10 mg/kg with LP-12.5 mg/kg suppressed more than 90% of BT-474 tumor cells growth in a nude mouse xenograft model, compared to individual OC or LP treatment. Activated c-Met, EGFR, HER2, and protein kinase B (AKT) were significantly suppressed in combination-treated mice tumors, compared to OC or LP monotherapy. This study reveals the OC future potential as combination therapy to sensitize HER2-overexpressing breast cancers and significantly reduce required doses of targeted HER family therapeutics.

131 -Oxophorbine protopheophorbide A from Ziziphus lotus as a novel mesenchymal-epithelial transition factor receptor inhibitory lead for the control of breast tumor growth in vitro and in vivo.

The failure of chemotherapy especially in triple negative breast cancer (TNBC) patients has been correlated with the overexpression of the mesenchymal-epithelial transition factor (c-Met) receptor. Thus, the hepatocyte growth factor (HGF)/c-Met signaling axis has gained considerable attention as a valid molecular target for breast cancer therapy. This study reports for the first time the discovery of the 131 -oxophorbines pheophorbide A and protopheophorbide A along with chlorophyllide A from Ziziphus lotus, an edible typical Tunisian plant, as the potent antiproliferative compounds against the human breast cancer cells MDA-MB-231 and MCF-7. Compared to other compounds, protopheophorbide A exerted the highest light-independent antiproliferative effect against the metastatic TNBC MDA-MB-231 cells (IC50 = 6.5 µM). In silico, this compound targeted the kinase domain of multiple c-Met crystal structures. It potently inhibited the kinase domain phosphorylation of wild and mutant c-Met in Z-LYTE kinase assay. Protopheophorbide A inhibited HGF-induced downstream c-Met-dependent cell proliferation, survival, adhesion and migration through RAF/MEK/ERK and PI3K/PTEN/AKT signaling pathways modulation, ROS generation and activation of JNK and p38 pathways. Interestingly, this compound impaired the ability of the MDA-MB-231 cells to adhere at different extracellular matrix proteins by reducing the HGF-induced expression of integrins αv, ß3, α2, and ß1. Moreover, protopheophorbide A exhibited anti-migratory properties (IC50 = 2.2 µM) through impacting the expression levels of E-cadherin, vimentin, ß-catenin, FAK, Brk, Rac, and Src proteins. Importantly, treatment with protopheophorbide A significantly inhibited the MDA-MB-231 tumor growth in vivo. Our results suggest that protopheophorbide A could be a novel c-Met inhibitory lead with promise to control c-Met/HGF-dependent breast malignancies.

Rutin as A Novel c-Met Inhibitory Lead for The Control of Triple Negative Breast Malignancies.

Triple negative breast cancer (TNBC) has high metastatic and mortality potential and lacks effective and selective therapeutic options. Aberrant dysregulation of the receptor tyrosine kinase c-Met promotes TNBC progression, motility and survival and therefore considered a valid therapeutic target. Among various identified anticancer agents, plant polyphenols (PPs) including flavonoids, have been shown to be safe and proven for their antitumor activity through modulating diverse macromolecular targets. This study reports the bioassay-guided identification of the common flavonol glycoside rutin as breast cancer cell proliferation, migration and invasion inhibitor. The cell free Z'-LYTE kinase assay, Western blot and in silico docking experiments uncovered, for the first time, c-Met kinase as a potential mechanistic target for rutin-mediated anticancer effects on TNBC cell lines. Likewise, the intraperitoneal injection of rutin at 30 mg/kg, 3X/week, significantly reduced the growth of the TNBC MDA-MB-231/GFP orthotopic xenograft in nude mouse model. These results clearly designate the functional dietary flavonoid rutin as a potential lead for the prevention and control of c-Met-dependent breast malignancies.

Acylated Iridoids and Rhamnopyranoses from Premna odorata (Lamiaceae) as Novel Mesenchymal-Epithelial Transition Factor Receptor Inhibitors for the Control of Breast Cancer.

Phytochemical investigation of Premna odorata Blanco, Lamiaceae, leaves afforded three new acylated iridoid glycosides 1-3 and two new acylated rhamnopyranoses 9 and 10, in addition to ten known compounds. The structures of the new compounds were confirmed using extensive 1D and 2D NMR analysis. Molecular modeling study suggested the potential of the acylated rhamnopyranoses to bind at the c-Met kinase domain. Cell-free Z'-LYTE™ assay testing revealed the good c-Met phosphorylation inhibitory activity of 9, followed by 8, and 10, with IC50 values of 2.5, 6.9, and 12.7 µM, respectively. The (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cell proliferation assay testing against the human c-Met expressing highly invasive MDA-MB-231 suggested compound 9 as the most active with IC50 value of 13.3 µM. Testing of compound 9 against multiple phenotypic breast cancer cell lines including MCF-7, BT-474 cells, and MDA-MB-468 proved enhanced activity against the highly c-Met expressing triple-negative breast cancer cell lines. Acylated rhamnopyranoses are potential novel c-Met inhibitors appropriate for future optimizations to control c-Met-dependent breast malignancies. Copyright © 2017 John Wiley & Sons, Ltd.

The tobacco cembranoid (1S,2E,4S,7E,11E)-2,7,11-cembratriene-4,6-diol as a novel angiogenesis inhibitory lead for the control of breast malignancies.

(1S,2E,4S,6R,7E,11E)-2,7,11-cembratriene-4,6-diol (1) and its 4-epi-analog (2) are diterpene precursors of the key flavor components in most Nicotiana (tobacco) species that purposely degraded during commercial tobacco fermentation. Angiogenesis, recruitment of new blood vessels, is important for tumor growth, survival and metastasis that can be targeted to control cancer. This study shows evidences and potential of the cembranoid 1 as a potent angiogenesis modulator through targeting VEGFR2. In silico study suggested favorable docking scores and binding affinity of 1 at the ATP binding pocket of VEGFR2. The binding mode of 1 was parallel to the standard FDA-approved antiangiogenic drug sunitinib (4). In vitro, cembranoid 1 significantly reduced the activated VEGFR2 levels in multiple breast cancer cell lines. Intraperitoneal 40mg/kg, 3X/week treatment of 1 significantly reduced the MDA-MB-231 cells breast tumor size in mice. Immunohistochemistry and Western blotting analysis of the treated mice tumors showed significant downregulation of the vasculogenesis marker CD31 and suppressed activated VEGFR2-paxillin-FAK pathway. Matrigel study in Swiss albino mice showed similar trend. The tobacco cembranoid 1 is a potential antiangiogenic lead useful for future use to control breast malignancies.

The olive oil phenolic (-)-oleocanthal modulates estrogen receptor expression in luminal breast cancer in vitro and in vivo and synergizes with tamoxifen treatment.

Luminal breast cancer represents a therapeutic challenge in terms of aggressive disease and emerging resistance to targeted therapy. (-)-Oleocanthal has demonstrated anticancer activity in multiple human cancers. The goal of this study was to explore the effect of (-)-oleocanthal treatment on growth of luminal breast cancer cells and to examine the effect of combination of (-)-oleocanthal with tamoxifen. Results showed that (-)-oleocanthal inhibited growth of BT-474, MCF-7, and T-47D human breast cancer cells in mitogen-free media with IC50 values of 32.7, 24.07, and 80.93µM, respectively. Similarly, (-)-oleocanthal suppressed growth of BT-474, MCF-7, and T-47D cells in 17ß-estradiol-supplemented media with IC50 values of 22.28, 20.77, and 83.91µM, respectively. Combined (-)-oleocanthal and tamoxifen treatments resulted in a synergistic growth inhibition of BT-474, MCF-7, and T-47D cells with combination index values of 0.65, 0.61, and 0.53 for each cell line, respectively. In-silico docking studies indicated high degree of overlapping for the binding of (-)-oleocanthal and 17ß-estradiol to estrogen receptors, while (-)-oleocanthal and tamoxifen have distinguished binding modes. Treatment with 5mg/kg or 10mg/kg (-)-oleocanthal resulted in 97% inhibition of tumor growth in orthotopic athymic mice bearing BT-474 tumor xenografts compared to vehicle-treated animals. (-)-Oleocanthal treatment reduced total levels of estrogen receptors in BT-474 cells both in vitro and in vivo. Collectively, (-)-oleocanthal showed a potential beneficial effect in suppressing growth of hormone-dependent breast cancer and improving sensitivity to tamoxifen treatment. These findings provide rational for evaluating the effect of (-)-oleocanthal in combination with endocrine treatments in luminal breast cancer.

The marine-derived pachycladin diterpenoids as novel inhibitors of wild-type and mutant EGFR.

Epidermal growth factor receptor (EGFR) is a key player in proliferation and metastasis of various cancers. Discovery of novel EGFR inhibitors is still an urgent clinical oncology unmet need. Pachycladins are eunicellin-based diterpenoids isolated from the soft coral Cladiella pachycladous species. This study evaluated the anticancer activity of pachycladins A-E against diverse breast and cervical cancer cells. Pachycladin A (1) potently inhibited the proliferation of multiple cancer cell lines, without being cytotoxic to non-cancerous cells. The antiproliferative activity of 1 is mediated through cytostatic mechanisms rather than inducing apoptosis, as evidenced by lack of TUNEL response. Additionally, 1 arrested cell cycle in either G1 or G2/M phase, according to the cancer type, which induced caspase-dependent and independent apoptosis only after prolonged treatment. Meanwhile, 1 potently decreased microvessel formation and endothelial cell migration, suggesting its potential antiangiogenic activity. Different kinase profiling platforms revealed the exquisite potency and selectivity of 1 towards EGFR, even compared to other members of the EGFR family. In cancer cells, the antiproliferative activity of 1 was associated with suppression of EGFR activation and its downstream effectors. Interestingly, 1 significantly inhibited the drug-resistant T790M EGFR mutant, which is believed to be an attractive feature of EGFR inhibitors. Docking studies characterized the structural determinants required for efficient wild and mutant EGFR inhibition. Overlay studies of 1 with known EGFR inhibitors provided future guidance to chemically improve its binding affinity. Together, the anticancer activity of 1 is mediated by direct effects on tumor growth and angiogenesis, selectively via deactivating EGFR signaling, providing an excellent scaffold to control EGF-dependent cancers.

(1S,2E,4S,7E,11E)-2,7,11-Cembratriene-4,6-diol semisynthetic analogs as novel c-Met inhibitors for the control of c-Met-dependent breast malignancies.

(1S,2E,4S,6R,7E,11E)-2,7,11-Cembratriene-4,6-diol (1) and its 4-epi-analog (2) are the cembranoid precursors to several key flavor ingredients in most Nicotiana (tobacco) species. Nearly 40-60% of 1 and 2 are purposely degraded during the commercial tobacco fermentation. However, 1 and 2 display promising bioactivities, including anticancer. Breast cancer is the most diagnosed cancer in women and ranked second female disease killer. The receptor tyrosine kinase c-Met correlates with aggressiveness of certain breast cancer phenotypes and thus considered a valid therapeutic target. This study reports the discovery and optimization of the tobacco-based cembranoid 1 as a novel c-Met inhibitory scaffold using combined structure- and ligand-based approaches. 1 displayed antiproliferative, anti-migratory and anti-invasive effects against the c-Met overexpressing MDA-MB-231 breast cancer cells at moderate µM concentrations. The Z'-LYTE kinase platform and Western blot analysis identified c-Met as a potential macromolecular target. Rationally designed carbamate analogs were proposed to probe additional targeted c-Met interactions and improve the cellular potency. The 6-phenyl carbamate 3 showed enhanced c-Met inhibitory activity. Structure-activity relationships of different substituents on the 3's phenyl moiety were studied. The most active analog 20 showed potent in vitro anticancer activity against the MDA-MB-231 breast cancer cells at low µM concentrations, with minimal toxicity on the non-tumorigenic MCF-10A mammary epithelial cells. Cembranoid 20 potently inhibited the c-Met catalytic activity in Z'-LYTE kinase assay and various cellular c-Met-driven signaling pathways. Furthermore, 20 displayed a robust antitumor activity in a breast cancer xenograft athymic mouse model and thus promoted to the lead rank. Cembranoids are novel c-Met inhibitors appropriate for future use to control c-Met dependent malignancies.

Novel c-Met inhibitory olive secoiridoid semisynthetic analogs for the control of invasive breast cancer.

Dysregulated receptor tyrosine kinase c-Met and its ligand HGF is valid and attractive molecular target for therapeutic blockade in cancer. Inspired by the chemical structure of the naturally occurring olive secoiridoid (-)-oleocanthal (1) and its documented anticancer activity against c-Met-dependent malignancies, a previous study reported tyrosol sinapate (4) as a c-Met inhibitor hit. This study reports additional semisynthetic optimization and SAR of 4 to improve its selective activity against c-Met-dependent breast cancer by increasing its capacity to inhibit c-Met phosphorylation. Forty-three compounds (5-47) were synthesized, among which the novel analog homovanillyl sinapate (HVS-16) was distinguished for its remarkable activity. HVS-16 substantially impaired c-Met-mediated proliferation, migration, and invasion across human breast cancer cell lines in two- and three-dimensional culture systems, while similar treatment doses were found to have effect neither on the non-tumorigenic human mammary epithelial cell growth nor on the c-Met independent breast cancer cell viability. HVS-16 showed a dose-dependent inhibition of ligand-mediated c-Met activation in human breast cancer cells. Docking studies revealed that HVS-16 fits very well inside c-Met crystal structures, satisfying critical interactions at the ATP binding site. This study identified important structural pharmacophoric features in HVS-16 and correlated its postulated binding pose with c-Met kinase assay data that would guide future olive secoiridoid bioisostere lead design. Results presented herein suggest HVS-16 as a promising c-Met inhibitor validated hit with potential to control invasive breast malignancies with aberrant c-Met activity.

The oleocanthal-based homovanillyl sinapate as a novel c-Met inhibitor.

The hepatocyte growth factor (HGF)/mesenchymal-epithelial transition factor (c-Met) signaling axis has gained considerable attention as an attractive molecular target for therapeutic blockade of cancer. Inspired by the chemical structure of S (-)-oleocanthal, a natural secoiridoid from extra-virgin olive oil with documented anticancer activity against c-Met-dependent malignancies, the research presented herein reports on the discovery of the novel olive-derived homovanillyl sinapate (HVS) as a promising c-Met inhibitor. HVS was distinguished for its remarkable potency against wild-type c-Met and its oncogenic variant in cell-free assays and confirmed by in silico docking studies. Furthermore, HVS substantially impaired the c-Met-mediated growth across a broad spectrum of breast cancer cells, while similar treatment doses had no effect on the non-tumorigenic mammary epithelial cell growth. In addition, HVS caused a dose-dependent inhibition of HGF-induced, but not epidermal growth factor (EGF)-induced, cell scattering in addition to HGF-mediated migration, invasion, and 3-dimensional (3D) proliferation of tumor cell spheroids. HVS treatment effects were mediated via inhibition of ligand-mediated c-Met activation and its downstream mitogenic signaling and blocking molecular mediators involved in cellular motility across different cellular contexts. An interesting feature of HVS is its good selectivity for c-Met and Abelson murine leukemia viral oncogene homolog 1 (ABL1) when profiled against a panel of kinases. Docking studies revealed interactions likely to impart high dual affinity for both ABL1 and c-Met kinases. HVS markedly reduced tumor growth, showed excellent pharmacodynamics, and suppressed cell proliferation and microvessel density in an orthotopic model of triple negative breast cancer. Collectively, the present findings suggested that the oleocanthal-based HVS is a promising c-Met inhibitor lead entity with excellent therapeutic potential to control malignancies with aberrant c-Met activity.

Norstictic Acid Inhibits Breast Cancer Cell Proliferation, Migration, Invasion, and In Vivo Invasive Growth Through Targeting C-Met.

Breast cancer is a major health problem affecting the female population worldwide. The triple-negative breast cancers (TNBCs) are characterized by malignant phenotypes, worse patient outcomes, poorest prognosis, and highest mortality rates. The proto-oncogenic receptor tyrosine kinase c-Met is usually dysregulated in TNBCs, contributing to their oncogenesis, tumor progression, and aggressive cellular invasiveness that is strongly linked to tumor metastasis. Therefore, c-Met is proposed as a promising candidate target for the control of TNBCs. Lichens-derived metabolites are characterized by their structural diversity, complexity, and novelty. The chemical space of lichen-derived metabolites has been extensively investigated, albeit their biological space is still not fully explored. The anticancer-guided fractionation of Usnea strigosa (Ach.) lichen extract led to the identification of the depsidone-derived norstictic acid as a novel bioactive hit against breast cancer cell lines. Norstictic acid significantly suppressed the TNBC MDA-MB-231 cell proliferation, migration, and invasion, with minimal toxicity to non-tumorigenic MCF-10A mammary epithelial cells. Molecular modeling, Z'-LYTE biochemical kinase assay and Western blot analysis identified c-Met as a potential macromolecular target. Norstictic acid treatment significantly suppressed MDA-MB-231/GFP tumor growth of a breast cancer xenograft model in athymic nude mice. Lichen-derived natural products are promising resources to discover novel c-Met inhibitors useful to control TNBCs.

The indole alkaloid meleagrin, from the olive tree endophytic fungus Penicillium chrysogenum, as a novel lead for the control of c-Met-dependent breast cancer proliferation, migration and invasion.

Fungi of the genus Penicillium produce unique and chemically diverse biologically active secondary metabolites, including indole alkaloids. The role of dysregulated hepatocyte growth factor (HGF) and its receptor, c-Met, in the development and progression of breast carcinoma is documented. The goal of this work is to explore the chemistry and bioactivity of the secondary metabolites of the endophytic Penicillium chrysogenum cultured from the leaf of the olive tree Olea europea, collected in its natural habitat in Egypt. This fungal extract showed good inhibitory activities against the proliferation and migration of several human breast cancer lines. The CH2Cl2 extract of P. chrysogenum mycelia was subjected to bioguided chromatographic separation to afford three known indole alkaloids; meleagrin (1), roquefortine C (2) and DHTD (3). Meleagrin inhibited the growth of the human breast cancer cell lines MDA-MB-231, MDA-468, BT-474, SK BR-3, MCF7 and MCF7-dox, while similar treatment doses were found to have no effect on the growth and viability of the non-tumorigenic human mammary epithelial cells MCF10A. Meleagrin also showed excellent ATP competitive c-Met inhibitory activity in Z-Lyte assay, which was further confirmed via molecular docking studies and Western blot analysis. In addition, meleagrin treatment caused a dose-dependent inhibition of HGF-induced cell migration, and invasion of breast cancer cell lines. Meleagrin treatment potently suppressed the invasive triple negative breast tumor cell growth in an orthotopic athymic nude mice model, promoting this unique natural product from hit to a lead rank. The indole alkaloid meleagrin is a novel lead c-Met inhibitory entity useful for the control of c-Met-dependent metastatic and invasive breast malignancies.

Isothiocyanatostilbenes as novel c-Met inhibitors.

The hepatocyte growth factor receptor (HGFR or c-Met) is a driver of multiple cancer subtypes. While there are several c-Met inhibitors in development, few have been approved for clinical use, warranting the need for continued research and development of c-Met targeting therapeutic modalities. The research presented here demonstrates a particular class of compounds known as isothiocyanatostilbenes can act as c-Met inhibitors in multiple cancer cell lines. Specifically, we found that 4,4'-Diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS) and 4,4'-Diisothiocyanatodihydrostilbene-2,2'-disulfonic acid (H2DIDS) had c-Met inhibitory effective doses in the low micromolar range while 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic acid (SITS) and 4,4'-dinitrostilbene-2, 2'-disulfonic acid (DNDS) exhibited IC50s 100 to 1000 fold higher. These compounds displayed much greater selectivity for inhibiting c-Met activation compared to similar receptor tyrosine kinases. In addition, DIDS and H2DIDS reduced hepatocyte growth factor (HGF)-induced, but not epidermal growth factor (EGF)-induced, cell scattering, wound healing, and 3-dimensional (3D) proliferation of tumor cell spheroids. In-cell and cell-free assays suggested that DIDS and H2DIDS can inhibit and reverse c-Met phosphorylation, similar to SU11274. Additional data demonstrated that DIDS is tolerable in vivo. These data provide preliminary support for future studies examining DIDS, H2DIDS, and derivatives as potential c-Met therapeutics.