Isoliquiritin promote angiogenesis by recruiting macrophages to improve the healing of zebrafish wounds.

Licorice is a widely used herbal medicine for the treatment of various diseases in southern Europe and parts of Asia. It has been reported that the isoliquiritin (ISL) from Glycyrrhiza root has the activity of promoting angiogenesis. The purpose of this study was to investigate the effect of ISL on the wound healing activity of zebrafish and its mechanism. 6-month-old zebrafish were injured in the skin (2 mm in diameter) and then treated with ISL. By measuring wound size and by histological examination, we found that ISL improved wound healing. In addition, 4-day-old zebrafish embryos of double transgenic line [Tg(fli-1:EGFP)]/[Tg(mpeg:mCherry)] were suffered from tissue traumas and then treated with ISL. Through fluorescent microscopy, we found that ISL promoted macrophage recruitment and angiogenesis in the wound area. Through qPCR analysis, we found that ISL up-regulated the expression of genes related to inflammation and angiogenesis in zebrafish embryos. These results showed that ISL could promote inflammatory response and angiogenesis, which played key roles in promoting wound healing. Therefore, ISL can be used as a promising candidate to promote wound healing.

A systematical comparison of anti-angiogenesis and anti-cancer efficacy of ramucirumab, apatinib, regorafenib and cabozantinib in zebrafish model.

AIMS: Gastric cancer (GC) is one of the most common malignant tumors in the world. Anti-angiogenic therapy is a useful strategy for the treatment of advanced GC. This study was aimed to systemically compare the anti-angiogenesis, anti-cancer efficacy, as well as the safety of four known anti-angiogenic drugs, namely ramucirumab, apatinib, regorafenib and cabozantinib. MAIN METHODS: Anti-angiogenic effect was evaluated for the intersegmental vessels (ISVs) and subintestinal veins (SIVs) formation in the Tg (fli-1: EGFP) zebrafish embryos. Anti-cancer efficacy was tested for the in vivo cell proliferation in cell line derived tumor xenograft (CDX) model based on Tg (fli-1: EGFP) zebrafish embryos. KEY FINDINGS: All four drugs exhibited anti-angiogenic abilities and tumor inhibition effects in fli-1: EGFP transgenic zebrafish. Using zebrafish xenografted model, we found that effectiveness of ramucirumab in anti-GC-proliferation is better than apatinib, regorafenib and cabozantinib. The combination of anti-angiogenic drugs and cisplatin showed no significant benefit in tumors. Meanwhile, toxicity assay showed that all tested anti-angiogenic drugs could cause cardiovascular-related side effects. The therapeutic index (LD50/ED50) of cabozantinib is higher than apatinib and regorafenib, suggesting a potential as an anti-GC drug. SIGNIFICANCE: The comparison of GC-related anti-angiogenic drugs was first reported. It was found that cabozantinib had a potential as an anti-GC drug. Zebrafish model was an ideal animal model for the research of anti-angiogenic behaviors.

Cancer-associated fibroblast regulate proliferation and migration of prostate cancer cells through TGF-ß signaling pathway.

AIMS: Prostate cancer (PCa) incidence rates are rising in China currently. Cancer-associated fibroblasts (CAFs), as a major component of tumor microenvironment, are crucial for tumor progression. This study was aimed to explore the promotion effect of patient-derived CAFs on the proliferation and migration of prostate cancer cells. MAIN METHODS: CAFs were isolated from tumor tissues of PCa patients. The promotion effect of CAFs on the proliferation and migration of PC-3 and LNCaP cells were evaluated in vitro and in vivo. The concentration of TGF-ß1 was measured by Luminex assay. The blocking activity of LY2109761 on the promotion effect of CAFs was also evaluated. KEY FINDINGS: CAFs could significantly promote the proliferation and migration of PC-3 and LNCaP cells both in vitro and in vivo. TGF-ß1 was identified as a highly increased factor in CAFs-CM compared with the normal culture medium of these two cancer cell lines. TGF-ß receptor inhibitor LY2109761 could suppress the CAFs-induced cellular proliferation and migration of PC-3 cells but not LNCaP cells. SIGNIFICANCE: Our study suggested a crucial role for CAFs and TGF-ß signaling in the progression of PCa. Zebrafish xenograft model was an ideal animal model for the study of CAFs and cancer cell interaction.

Pro-angiogenic activity of isoliquiritin on HUVECs in vitro and zebrafish in vivo through Raf/MEK signaling pathway.

AIMS: Liquorice is a widely used herbal medicine for treating various diseases native to southern Europe and parts of Asia. Isoliquiritin (ISL), a licorice root-derived flavonoid, has been reported to exhibit antioxidant, anti-inflammatory, anti-genotoxic activity and anti-depression activities. This study was aimed to explore the pro-angiogenic activity of ISL and explicate the underlying mechanism. MAIN METHODS: In vitro, ISL-treated human umbilical vein endothelial cells (HUVECs) were analyzed for cell viability, cell migration and tube formation. In vivo, pro-angiogenic effects were evaluated for the intersegmental vessels (ISVs) formation in transgenic zebrafish embryos [Tg(fli-1: EGFP)]. Furthermore, a blocking assay with eight pathways-specific kinase inhibitors were also used to determine the potential pro-angiogenic mechanism of ISL. KEY FINDINGS: ISL counteracted tyrosine kinase inhibitor II (VRI)-induced endothelial cell apoptosis and promoted cell migration and tube formation in HUVECs. ISL markedly rescued ISVs loss induced by VRI in zebrafish embryos, probably by activating vascular endothelial growth factor receptor-2 (VEGFR-2), phosphoinositide 3-kinase (PI3K), Raf and mitogen-activated protein kinase (MEK)-dependent signaling pathways. SIGNIFICANCE: Our study first discovered and confirmed the pro-angiogenic activity of ISL both in HUVECs and zebrafish. Thus, ISL could be developed as a potential therapeutic agent by the role of pro-angiogenic activity for the treatment of cardiovascular diseases, cerebrovascular diseases and other vascular diseases.

Developmental toxicity of 2,4-dichlorophenoxyacetic acid in zebrafish embryos.

2,4-Dichlorophenoxyacetic acid (2,4-D) is widely used in agriculture as herbicide/pesticide, plant growth regulator and fruit preservative agent. It progressively accumulates in the environment including surface water, air and soil. It could be detected in human food and urine, which poses great risk to the living organisms. In the present study, we investigated the developmental toxicity of 2,4-D on zebrafish (Danio rerio) embryo. 2,4-D exposure significantly decreased both the survival rate (LC50 = 46.71 mg/L) and hatching rate (IC50 = 46.26 mg/L) of zebrafish embryos. The most common developmental defect in 2,4-D treated embryos was pericardial edema. 2,4-D (25 mg/L) upregulated marker genes of cardiac development (vmhc, amhc, hand2, vegf, and gata1) and downregulated marker genes of oxidative stress (cat and gpx1a). Whole mount in situ hybridization confirmed the vmhc and amhc upregulation by 2,4-D treatment. LC/MS/MS showed that the bioaccumulation of 2,4-D in zebrafish embryos were increased in a time-dependent manner after 25 mg/L of 2,4-D treatment. Taken together, our study investigated the toxic effects of 2,4-D on zebrafish embryonic development and its potential molecular mechanisms, gave evidence for the full understanding of 2,4-D toxicity on living organisms and shed light on its environmental impact.

Mycophenolic Acid-Induced Developmental Defects in Zebrafish Embryos.

With the increasing use of mycophenolic acid (MPA) in solid organ transplantation, some clinical studies indicate that it is also a human teratogen. However, it is unknown by which mechanism MPA acts as a teratogen. Mycophenolic acid was a selective blocker of de novo purine synthesis, and its immunosuppressive effect is mediated by the inhibition of inosine monophosphate dehydrogenase, which could be a target for MPA-induced toxicity as well. The aim of our study was to examine the direct influence of MPA exposure on zebrafish (Danio rerio) embryos. Morphological defects including tail curvature and severe pericardial edema in zebrafish embryos caused by MPA (3.7-11.1 µmol/L) were found in a dose-dependent manner. The teratogenic index (25% lethal concentration value (LC25)/no observed adverse effect level ratio) was 16, which indicated MPA as a teratogen. Quantitative polymerase chain reaction analysis revealed that the expression level of impdh1b and impdh2 was significantly reduced by MPA treatment at 8 µmol/L (equals to LC25 level). All the toxic effects could be partially reversed by the addition of 33.3 µmol/L guanosine. Our results indicated that MPA impairs the development of zebrafish embryos via inhibition of impdh activity, which subsequently caused a guanosine nucleotide depletion in vivo.

Gambogic acid causes fin developmental defect in zebrafish embryo partially via retinoic acid signaling.

Gambogic acid (GA), the major active ingredient of gamboge, has been approved by the Chinese Food and Drug Administration for clinical trials in cancer patients due to its strong anticancer activity. However, our previous research showed that GA was teratogenic against zebrafish fin development. To explore the teratogenicity and the underlying mechanisms, zebrafish (Danio rerio) embryos were used. The morphological observations revealed that GA caused fin defects in zebrafish embryos in a concentration-dependent manner. The critical exposure time of GA to reveal teratogenicity was before 8 hpf (hours post fertilization). LC/MS/MS analysis revealed that a maximum bioconcentration of GA was occurred at 4 hpf. Q-PCR data showed that GA treatment resulted in significant inactivation of RA signaling which could be partially rescued by the exogenous supply of RA. These results indicate the potential teratogenicity of GA and provide evidence for a caution in its future clinic use.

Anti-angiogenic effect of auranofin on HUVECs in vitro and zebrafish in vivo.

Angiogenesis plays an essential role in many physiological and pathological processes. Auranofin (Ridaura®), an important gold(I) complex, is used to treat rheumatoid arthritis. However, the effect of auranofin on blood vessel formation is still unclear. In this study, we investigated the anti-angiogenic activity of auranofin on human umbilical vein endothelial cells (HUVEC) in vitro and zebrafish in vivo. Our results showed that auranofin could inhibit the proliferation, migration and tube formation of HUVECs and disrupted the formation of intersegmental vessels and the subintestinal vessels of zebrafish embryos. Auranofin inhibited the phosphorylation of vascular endothelial growth factor 2 (p-VEGFR2) on HUVECs and suppressed the vascular endothelial growth factor (VEGF) signaling pathway (vegfa, flt-1, kdr) but not thioredoxin reductase (TrxR) on zebrafish. Our study suggested that auranofin might serve as a potential anti-angiogenic compound candidate.

Toxicity assessment of 7 anticancer compounds in zebrafish.

Toxicity is one of the major reasons for failure in drug development. Zebrafish, as an ideal vertebrate model, could also be used to evaluate drug toxicity. In this study, we aimed to show the predictability and highlight novel findings of toxicity in zebrafish model. Seven anticancer compounds, including triptolide (TP), gambogic acid (GA), mycophenolic acid (MPA), curcumin, auranofin, thalidomide, and taxol, were assessed in zebrafish for their toxicity. Three compounds (GA, TP, and taxol) showed highest acute lethality, with 50% lethal concentration ≈ 1 µmol/L. Missing tails, severe pericardial edema, and enlarged yolk sacs were observed in MPA-treated embryos. The development of pectoral fins was severely disturbed in thalidomide-, GA-, and TP-treated embryos. Bradycardia was observed in MPA- and thalidomide-treated groups. Our findings suggested that the zebrafish are a good model for toxicity assessment of anticancer compounds.

Antiangiogenic effects and mechanisms of trans-ethyl p-methoxycinnamate from Kaempferia galanga L.

Kaempferia galanga L. (Zingiberaceae) is an aromatic herb and a popular spice used as a condiment in Asian cuisine. The ethanol extract of the dried plant and its successive four subfractions were investigated on zebrafish model by quantitative endogenous alkaline phosphatase assay. Both n-hexane and ethyl acetate fractions had antiangiogenic activity, and two major active components (trans-ethyl p-methoxycinnamate and kaempferol) showed potent antiangiogenic effects on wild-type zebrafish. Because of its much stronger effect and no antiangiogenic activity reported, trans-ethyl p-methoxycinnamate was further investigated for its action mechanism. It dose dependently inhibited vessel formation on both wild- and Tg(fli1a:EGFP)y1-type zebrafish embryos. The semiquantitative reverse transcription polymerase chain reaction assay suggested that trans-ethyl p-methoxycinnamate affects multiple molecular targets related to angiogenesis. In vitro, it specifically inhibited the migration and tube formation of human umbilical vein endothelial cells. In vivo, it could block bFGF-induced vessel formation on Matrigel plug assay.

Anti-angiogenic effects and mechanisms of zerumin A from Alpinia caerulea.

Alpinia caerulea (R.Br.) Bentham, a perennial herb growing in tropical and subtropical Australia, is used as a flavouring spice and a ginger substitute. Its fruit has been used as indigenous food among the aboriginal Australians; 95% ethanol extracts of the dried fruits, leaves, rhizomes and roots of this plant were investigated in a zebrafish model by quantitative endogenous alkaline phosphatase assay. Only the fruit extract showed potential anti-angiogenic effect, inhibiting vessel formation by 25% at 20µg/ml. Two diterpenoids were isolated and identified as zerumin A and (E)-8(17),12-labdadiene-15,16-dial. Zerumin A, which had mainly accumulated in the fruits and bearing a carboxylic group, could dose-dependently inhibit vessel formation, in both wild-type and Tg(fli1a:EGFP)y1 zebrafish embryos. The semi-quantitative reverse transcription polymerase chain reaction assay on wild type zebrafish embryos suggested that zerumin A affected multiple molecular targets related to angiogenesis. Further investigation, by human umbilical vein endothelial cell assays, revealed that zerumin A specifically inhibited the proliferation and migration steps, to prevent angiogenesis progress.

A high-sensitivity UPLC-MS/MS method for simultaneous determination and confirmation of triptolide in zebrafish embryos.

A high-sensitivity ultra-performance liquid-chromatography (UPLC) coupled with tandem mass spectrometric method was developed for simultaneous quantification and confirmation of triptolide in both zebrafish embryos and the aqueous-exposure solution on a tandem quadrupole mass spectrometer (TQ-MS). This was achieved by performing quantification using the multiple reaction monitoring (MRM) acquisition with simultaneous characterization of the MRM peak using product ion confirmation (PIC) acquisition as it elutes from the chromatographic system. Separation was achieved on a 1.7 µm C(18) UPLC column using 0.1% formic acid water-acetonitrile mobile phase with a cycle time of 6 min. The linear range of 0.115-360 ng/mL, and lower limits of detection of 0.02 ng/mL and quantification of 0.064 ng/mL were established. This method was successfully applied to determine the time course of triptolide absorption by zebrafish embryos and the amount of triptolide remaining in the culture medium after administration of two triptolide dosages at three time points. This coupled MRM with PIC approach could provide both qualitative and quantitative results without the need for repetitive analyses. This resulted in the reduction of further confirmative experiments and analytical time, and ultimately increased laboratory productivity.

Anti-angiogenic effect and mechanism of rhein from Rhizoma Rhei.

PURPOSE: Rhein is a major bioactive component in rhubarb (Dahuang), a famous traditional Chinese medicine derived from the rhizome of Rheum palmatum and related species. It was reported to have antitumor and anti-inflammatory properties. Our previous studies found rhein displaying potent anti-angiogenic activities in a zebrafish embryo model. Its action mechanisms need further elucidation. METHODS: The inhibition effect of vessel formation was checked by microscopic imaging on Tg(fli1a:EGFP)y1 zebrafish embryos. Then the action mechanism of rhein was investigated by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) on wild type zebrafish embryos and further tested on human umbilical vein endothelial cells. RESULTS: At 20µM, rhein could almost completely block intersegmental blood vessels formation at both 48 and 72hpf, and completely inhibit subintestinal vessel plexus formation at 72hpf. Rhein affected multiple molecular targets related to angiogenesis, particularly angpt2 and tie2, and also inhibited endothelial cell migration. CONCLUSION: Rhein could inhibit angiogenesis, which may play a role in antitumor and anti-inflammatory actions.

Anti-angiogenic effects of the fruit of Alpinia oxyphylla.

AIM OF STUDY: The fruit of Alpinia oxyphylla, an herb commonly used in East Asian medicine, is variously used for the treatment of cancer and inflammatory conditions, which may possibly be mediated through anti-angiogenesis. This study aims to check for anti-angiogenic functions in the herb. MATERIALS AND METHODS: The 95% ethanol extract and four subsequent fractions (n-hexane, ethyl acetate, n-butanol and aqueous fractions) of the fruit of A. oxyphylla were tested on zebrafish model by quantitative endogenous alkaline phosphatase assay; then the active fractions were further tested on wild type and Tg(fli1a:EGFP)y1 zebrafish embryos and human umbilical vein endothelial cells and tumor cell lines for the anti-angiogenic effects. RESULTS: The n-hexane and ethyl acetate fractions showed anti-angiogenic potentials in both in vivo and in vitro models. CONCLUSIONS: The use of A. oxyphylla for cancer and inflammation diseases may be partly due to its effects against vessel formation.

Anti-angiogenic effects of rhubarb and its anthraquinone derivatives.

ETHNOPHARMACOLOGICAL RELEVANCE: Rhubarb root (Dahuang) is often included as an ingredient in traditional Chinese compound prescriptions for the treatment of inflammatory diseases. This application may possibly be mediated through anti-angiogensis and thus would shed light on its potential value in cancer therapy. AIM OF THE STUDY: To elucidate the anti-angiogenic properties of rhubarb root, we tested the inhibitory effects of different fractions and a series of anthraquinone derivatives against vessel formation in zebrafish embryos. MATERIALS AND METHODS: The 95% ethanol extract and four subsequent fractions (n-hexane, ethyl acetate, n-butanol and aqueous fractions) of rhubarb root and five anthraquinone derivatives were investigated on zebrafish model by quantitative endogenous alkaline phosphatase assay and staining assay. RESULTS: Ethyl acetate fraction showed the strongest inhibition of vessel formation by 52%. Three anthraquinones (aloe-emodin, emodin and rhein) displayed potent anti-angiogenic activities. CONCLUSIONS: The angiogenic properties of rhubarb root may partly account for its use in inflammatory diseases. The anthraquinones with acidic or polar, hydrophilic substitution at C-6 or C-3 positions played a substantial role in inhibiting angiogenesis. The value of the zebrafish angiogenic model is further supported.