Search for Anti-angiogenic Substances from Natural Sources

A 1, 4-benzoquinone derivative isolated from Ardisia crispa (Thunb.) A. DC. root suppresses angiogenesis via its angiogenic signaling cascades

The root hexane extract of Ardisia crispa (ACRH), which belongs to the Primulaceae family, has been reported to possess anti-inflammatory, chemopreventive, anti-arthritic, and antiangiogenic activities. In this study, we isolated a p-benzoquinone derivative, 2-methoxy-6-undecyl-1,4-benzoquinone (AC2), from ACRH and investigated its potential antiangiogenic activity in human umbilical vein endothelial cells (HUVECs) and zebrafish embryo models. Prior to this study, AC2 was characterized using 1H NMR spectroscopy and MS. AC2 significantly suppressed HUVEC proliferation in a time-independent manner, with an IC50 value of 1.35 ± 0.05, 1.15 ± 0.02, and 1.00 ± 0.01 µg/mL at 24, 48, and 72 h, respectively. AC2 also induced apoptosis in HUVECs and significantly suppressed their migration, invasion, and tube formation in a concentration-dependent manner. Additionally, AC2 significantly attenuated most of the analyzed protein markers, including pro-MMP-2, VEGF-C, VEGF-D, angiopoietin-2, endothelin-1, fibroblast growth factor (FGF)-1, FGF-2, follistatin, heparin-binding epidermal growth factor-like growth factor (HB-EGF), and hepatocyte growth factor (HGF) at all tested concentrations. Furthermore, AC2 significantly inhibited zebrafish embryo intersegmental vessels (ISVs), confirming its antiangiogenic role. In conclusion, AC2 exhibits a potential anti-angiogenic effect by suppressing several proangiogenic and growth factors. Further studies are needed to investigate their effects on other excessive angiogenic diseases.

Inhibitory potency of the nettle lectin on neovascularization: a biomolecule for carbohydrate-mediated targeting of angiogenesis

BACKGROUND

Current angiogenesis inhibitors target cellular vascularization processes, including proliferation, migration, and tube formation. In this study, we investigated the impact of Urtica dioica agglutinin (UDA) on the cellular vascularization process.

METHODS AND RESULTS

Various concentrations of UDA were applied to normal (HUVEC, MCF-10 A, and HDF from humans, and L-929 from mice) and cancer (A431 and U87 from humans, and 4T1 from mice) cell lines at different times. The MTT, cell migration assay, differentiation of endothelial cells, expression of VEGF-A/VEGF-R2, and integrin α2 were evaluated. The MTT results demonstrated that UDA was non-toxic to normal cells while inhibiting the growth of neoplastic cells. The migratory capacity of HUVECs and U87 glioblastoma cells was inhibited by UDA in the wound repair model. This lectin inhibited HUVEC-induced vessel sprouting in the collagen-cytodex matrix. In addition, UDA treatment reduced VEGF-integrin cross-talk in HUVECs, confirming the anti-angiogenic activity of this molecule.

CONCLUSIONS

Based on our findings, UDA may have an effect on cancer cell proliferation and vascularization events while causing minimal toxicity to normal cells via binding glyco-conjugates containing GlcNAc/man oligomers like EGFR. This is a blue clue for the angiogenesis-related therapeutic importance of UDA.

The potential of marine resources for retinal diseases: a systematic review of the molecular mechanisms

We rely on vision more than on any other sense to obtain information about our environment. Hence, the loss or even impairment of vision profoundly affects our quality of life. Diet or food components have already demonstrated beneficial effects on the development of retinal diseases. Recently, there has been a growing interest in resources from marine animals and plants for the prevention of retinal diseases through nutrition. Especially fish intake and omega-3 fatty acids have already led to promising results, including associations with a reduced incidence of retinal diseases. However, the underlying molecular mechanisms are insufficiently explained. The aim of this review was to summarize the known mechanistic effects of marine resources on the pathophysiological processes in retinal diseases. We performed a systematic literature review following the PRISMA guidelines and identified 107 studies investigating marine resources in the context of retinal diseases. Of these, 46 studies described the underlying mechanisms including anti-inflammatory, antioxidant, antiangiogenic/vasoprotective, cytoprotective, metabolic, and retinal function effects, which we critically summarize. We further discuss perspectives on the use of marine resources for human nutrition to prevent retinal diseases with a particular focus on regulatory aspects, health claims, safety, and bioavailability.

Saikosaponin A, a Triterpene Saponin, Suppresses Angiogenesis and Tumor Growth by Blocking VEGFR2-Mediated Signaling Pathway

Saikosaponin A (SSA), a main triterpenoid saponin component from Radix Bupleurum, has been revealed to have a variety of pharmacological activities. However, whether SSA can inhibit angiogenesis, a key step in solid tumor progression, remains unknown. In this study, we demonstrated that SSA could powerfully suppress the proliferation, migration, and tube formation of human umbilical vein endothelial cells. SSA also significantly inhibited angiogenesis in the models of the chick embryo chorioallantoic membrane and Matrigel plugs. Moreover, SSA was found to inhibit tumor growth in both orthotopic 4T1 breast cancer and subcutaneous HCT-15 colorectal tumor by the inhibition of tumor angiogenesis. Western blot assay indicated the antiangiogenic mechanism of SSA in the suppression of the protein phosphorylation of VEGFR2 and the downstream protein kinase including PLCγ1, FAK, Src, and Akt. In summary, SSA can suppress angiogenesis and tumor growth by blocking the VEGFR2-mediated signaling pathway.

Ardisia crispa root hexane fraction suppressed angiogenesis in human umbilical vein endothelial cells (HUVECs) and in vivo zebrafish embryo model

Ardisia crispa Thunb. A. DC. (Primulaceae) has been used extensively as folk-lore medicine in South East Asia including China and Japan to treat various inflammatory related diseases. Ardisia crispa root hexane fraction (ACRH) has been thoroughly studied by our group and it has been shown to exhibit anti-inflammatory, anti-hyperalgesic, anti-arthritic, anti-ulcer, chemoprevention and suppression against inflammation-induced angiogenesis in various animal model. Nevertheless, its effect against human endothelial cells in vitro has not been reported yet. Hence, the aim of the study is to investigate the potential antiangiogenic property of ACRH in human umbilical vein endothelial cells (HUVECs) and zebrafish embryo model. ACRH was separated from the crude ethanolic extract of the plant's root in prior to experimental studies. MTT assay revealed that ACRH exerted a concentration-dependent antiproliferative effect on HUVEC with the IC₅₀ of 2.49 ± 0.04 μg/mL. At higher concentration (10 μg/mL), apoptosis was induced without affecting the cell cycle distribution. Angiogenic properties including migration, invasion and differentiation of HUVECs, evaluated via wound healing, trans-well invasion and tube formation assay respectively, were significantly suppressed by ACRH in a concentration-dependent manner. Noteworthily, significant antiangiogenic effects were observed even at the lowest concentration used (0.1 μg/mL). Expression of proMMP-2, vascular endothelial growth factor (VEGF)-C, VEGF-D, Angiopoietin-2, fibroblast growth factor (FGF)-1, FGF-2, Follistatin, and hepatocyte growth factor (HGF) were significantly reduced in various degrees by ACRH. The ISV formation in zebrafish embryo was significantly suppressed by ACRH at the concentration of 5 μg/mL. These findings revealed the potential of ACRH as antiangiogenic agent by suppressing multiple proangiogenic proteins. Thus, it can be further verified via the transcription of these proteins from their respective DNA, in elucidating their exact pathways.

An Insight Into the Molecular Mechanism of Berberine Towards Multiple Cancer Types Through Systems Pharmacology

Over the past several decades, natural products with poly-pharmacological profiles have demonstrated promise as novel therapeutics for various complex diseases, including cancer. Berberine (PubChem CID: 2353), a soliloquies quaternary alkaloid, has been validated to exert powerful effects in many cancers. However, the underlying molecular mechanism is not yet fully elucidated. In this study, we summarized the molecular effects of berberine against multiple cancers based on current available literatures. Furthermore, a systems pharmacology infrastructure was developed to discover new cancer indications of berberine and explore their molecular mechanisms. Specifically, we incorporated 289 high-quality protein targets of berberine by integrating experimental drug-target interactions (DTIs) extracted from literatures and computationally predicted DTIs inferred by network-based inference approach. Statistical network models were developed for identification of new cancer indications of berberine through integration of DTIs and curated cancer significantly mutated genes (SMGs). High accuracy was yielded for our statistical models. We further discussed three typical cancer indications (hepatocarcinoma, lung adenocarcinoma, and bladder carcinoma) of berberine with new mechanisms of actions (MOAs) based on our systems pharmacology framework. In summary, this study systematically provides a powerful strategy to identify potential anti-cancer effects of berberine with novel mechanisms from a systems pharmacology perspective.

Plant Secondary Metabolites as Anticancer Agents: Successes in Clinical Trials and Therapeutic Application

Cancer is a multistage process resulting in an uncontrolled and abrupt division of cells and is one of the leading causes of mortality. The cases reported and the predictions for the near future are unthinkable. Food and Drug Administration data showed that 40% of the approved molecules are natural compounds or inspired by them, from which, 74% are used in anticancer therapy. In fact, natural products are viewed as more biologically friendly, that is less toxic to normal cells. In this review, the most recent and successful cases of secondary metabolites, including alkaloid, diterpene, triterpene and polyphenolic type compounds, with great anticancer potential are discussed. Focusing on the ones that are in clinical trial development or already used in anticancer therapy, therefore successful cases such as paclitaxel and homoharringtonine (in clinical use), curcumin and ingenol mebutate (in clinical trials) will be addressed. Each compound’s natural source, the most important steps in their discovery, their therapeutic targets, as well as the main structural modifications that can improve anticancer properties will be discussed in order to show the role of plants as a source of effective and safe anticancer drugs.