Toluhydroquinone, the secondary metabolite of marine algae symbiotic microorganism, inhibits angiogenesis in HUVECs

In vitro and in vivo antimicrobial activity of the fungal metabolite toluquinol against phytopathogenic bacteria

Introduction

Bacterial plant diseases cause tremendous economic losses worldwide. However, a few effective and sustainable control methods are currently available. To discover novel and effective management approaches, we screened marine fungi for their antibacterial activity against phytopathogenic bacteria in vitro and in vivo.

Methods

We screened the culture broth of 55 fungal strains isolated from various marine sources (seawater, algae, and sediment) for their in vitro antibacterial activity using the broth microdilution method. Then, only the fungal strain (designated UL-Ce9) with higher antibacterial activity in vitro was tested in an in vivo experiment against tomato bacterial wilt. The active compounds of UL-Ce9 were extracted using ethyl acetate, purified by a series of chromatography, and the structure was elucidated by nuclear magnetic resonance spectroscopy. Pesticide formulations of toluquinol were prepared as soluble concentrates and wettable powder. The disease control efficacy of toluquinol formulations was evaluated against blight of rice and the bacterial wilt of tomato.

Results and discussion

The culture broth of UL-Ce9 showed high antibacterial activity against Agrobacterium tumefaciens, Ralstonia solanacearum, and Xanthomonas arboricola pv. pruni in vitro, and we selected UL-Ce9 for the in vivo test. The UL-Ce9 culture broth completely suppressed the bacterial wilt of tomato at a dilution of 1:5. The phylogenetic analysis identified UL-Ce9 as Penicillium griseofulvum, and the antibacterial metabolites were revealed as patulin, gentisyl alcohol, and toluquinol, all of which were associated with the biosynthetic pathway of the mycotoxin patulin. Patulin exhibited the highest antibacterial activity against 16 phytopathogenic bacteria in vitro, followed by toluquinol and gentisyl alcohol. As patulin is toxic, we selected toluquinol to investigate its potential use as a pesticide against bacterial plant diseases. Compared with the chemicals currently being applied in agriculture (streptomycin and oxytetracycline), toluquinol formulations exhibited similar and higher control efficacies against bacterial leaf blight of rice and bacterial wilt of tomato, respectively. To the best of our knowledge, this is the first report of the antibacterial activity of toluquinol against phytopathogenic bacteria. Our results suggest that toluquinol is a potential candidate for the development of novel and effective pesticides for the management of bacterial plant diseases.

Efficacy of marine biomolecules on angiogenesis by targeting hypoxia inducible factor/vascular endothelial growth factor signaling in zebrafish model

Marine resources are notably explored for their unique biomolecules that have been designed to be drug targets for their immense potential against various pathologies. These biomolecules are mostly secondary metabolites from different species that include sponges, tunicates, echinoderms, ascidians, algae, and marine symbionts. Among the various biological activities of the marine biomolecules, antiangiogenic property has gained much significance in alternate therapy for treatment against cancer. Hypoxia inducible factor (HIF) and vascular endothelial growth factor (VEGF) are the prime signaling pathways related to angiogenesis that are exclusively designated as markers for critical selection of novel inhibitors. This is mainly due to their importance in tumor induction and regulatory control over other interlinked pathways involved in cancer. Small molecular drug screening using the zebrafish model has been an advantage in cancer research in recent times. This review addresses the importance of marine biomolecules and their antiangiogenic efficacy by targeting HIF/VEGF pathways experimented in the zebrafish model in the last decade. Thus, it would provide more clear insights into the role of biomolecules in alternative cancer therapy.

Sphingosine-1-phosphate promotes PDGF-dependent endothelial progenitor cell angiogenesis in human chondrosarcoma cells

The malignant bone tumors that are categorized as chondrosarcomas display a high potential for metastasis in late-stage disease. Higher-grade chondrosarcomas contain higher levels of expression of platelet-derived growth factor (PDGF) and its receptor. The phosphorylation of sphingosine by sphingosine kinase enzymes SphK1 and SphK2 generates sphingosine-1-phosphate (S1P), which inhibits human chondrosarcoma cell migration, while SphK1 overexpression suppresses lung metastasis of chondrosarcoma. We sought to determine whether S1P mediates levels of PDGF-A expression and angiogenesis in chondrosarcoma. Surprisingly, our investigations found that treatment of chondrosarcoma cells with S1P and transfecting them with SphK1 cDNA increased PDGF-A expression and induced angiogenesis of endothelial progenitor cells (EPCs). Ras, Raf, MEK, ERK and AP-1 inhibitors and their small interfering RNAs (siRNAs) inhibited S1P-induced PDGF-A expression and EPC angiogenesis. Our results indicate that S1P promotes the expression of PDGF-A in chondrosarcoma via the Ras/Raf/MEK/ERK/AP-1 signaling cascade and stimulates EPC angiogenesis.

Isolation and screening of proangiogenic and antiangiogenic metabolites producing rare actinobacteria from soil

AIMS

Angiogenesis is a physiological process that has important impacts on the pathology and healing of various diseases, and its induction or inhibition by bioactive actinobacterial metabolites can help the treatment of some diseases. In this study, the effects of actinobacterial extract in the process of angiogenesis have been explored.

METHODS AND RESULTS

In this research, proangiogenic and antiangiogenic metabolites producing actinobacteria were isolated from soil samples and their fermentation broth were extracted and after evaluation of their toxicity by MTT assay, antiangiogenic and proangiogenic activities were screened against human umbilical vein endothelial cells (HUVECs) by in vitro tube formation and migration assay. Isolated strains were identified through molecular techniques. The results showed that Nocardiopsis arvandica UTMC 103 and Nonomuraea sp. UTMC 2180 extracts had a high potential of anti-angiogenic activity on HUVECs.

CONCLUSIONS

For the first time proangiogenic potency of a rare actinobacterium, Kribbella sp. UTMC 522, was reported, and N. arvandica UTMC 103 and Nonomuraea sp. UTMC 2180 extracts inhibits the proliferation, migration and angiogenesis activity of HUVECs with reasonable potency.

SIGNIFICANCE AND IMPACT OF THE STUDY

Metabolites of the introduced rare actinobacteria are potent proangiogenic and angiogenic inhibitors. Identification of angiogenic-antiangiogenic mechanisms and purification of the extracts would be useful in therapeutic angiogenesis.

Investigation of the anti-angiogenesis effects induced by deoxypodophyllotoxin-5-FU conjugate C069 against HUVE cells

We have found that the deoxypodophyllotoxin-5-fluorouracil conjugate, 4'-O-demethyl-4-deoxyppodophyllotoxin-4'-yl 4-((6-(2-(5-fluorouracil-yl)acetamido) hexyl)amino)-4-oxobutanoate (C069), possessed superior cytotoxicities and less toxicity compared with etoposide. In this paper, the anti-angiogenic and vascular disrupting activities of C069 were examined with several in vitro and in vivo models. First, we demonstrated that C069 significantly inhibited the proliferation, migration, tube formation and disrupted the formed tube-like structures of HUVE cells, and inhibited angiogenesis in chicken chorioallantoic membrane assay. Furthermore, we found that C069 inhibited tube formation of HUVE cells by down-regulating the MMP-2, MMP-9, and phosphorylation of Akt and β-catenin. These results provided the initial evidence that C069 exerts potent anti-angiogenic and vascular disrupting effects.

The novel model peptide, αAL14, regulates angiogenesis by inhibiting VEGFR 2-mediated signaling in HUVECs

Inhibition of angiogenesis has been focused on as a strategy for treating several diseases including cancer. In this study, a novel model peptide αAL14 was synthesized and used to identify its inhibitory effects on angiogenesis. The anti-angiogenic effects of αAL14 were investigated using vascular endothelial cells, HUVECs. αAL14 inhibited critical angiogenic processes including tubule formation, cell migration and cell invasion with no influence on cell proliferation in HUVECs. Activity of VEGFR2 was inhibited by αAL14 treatment in HUVECs. Additionally, activities of major subsequent downstream factors of VEGFR2 such as ERK, FAK and Akt were decreased. αAL14 affected expression of Rac1, Cdc42, Arp2 and WAVE2 which are involved in formation of lamellipodia. Moreover, αAL14 reduced NF-κB that can promote expression of several genes relating to cell invasion such as MMP2 and MMP9. Therefore, the results suggest that αAL14 has a potential to be developed as anti-angiogenic drug for treating diseases driven by abnormal angiogenesis.

Desmethylanhydroicaritin isolated from Sophora flavescens, shows antitumor activities in U87MG cells via inhibiting the proliferation, migration and invasion

This study is the first report of the antitumor activities of desmethylanhydroicaritin (DMAI) isolated from Sophora flavescens on U87MG cells. Human glioblastoma is one of the most aggressive malignant type of brain tumors and highly diffuses to around normal brain tissues. DMAI showed anti-proliferation effects on U87MG cells at the concentration of 30μM, however did not affect to HEK-293 cells. DMAI induced anti-proliferation effects via ERK/MAPK, PI3K/Akt/mTOR signal pathway and G2/M phase cell cycle arrest. DMAI led to morphological change and inhibition of filapodia formation through regulation of Rac 1 and Cdc 42. In addition, migration and invasion of U87MG cells were inhibited by DMAI via down-regulation of matrix metalloproteinase (MMP) -2 and MMP -9 expressions and activities. Our results suggest that DMAI has a potential as a therapeutic agent against glioblastoma cells.

Toluhydroquinone from A spergillus sp. suppress inflammatory mediators via nuclear factor-κB and mitogen-activated protein kinases pathways in lipopolysaccharide-induced RAW264.7 cells

Objectives

The purpose of this study is to investigate anti-inflammatory effects of toluhydroquinone in lipopolysaccharide (LPS)-stimulated RAW264.7 cells.

Methods

Toluhydroquinone was purified from a fungal strain, Aspergillus sp. We investigated that levels of nitric oxide (NO) using Griess reagent, production of prostaglandin E2 (PGE2) and pro-inflammatory cytokines using ELISA assay. We conducted Western blot analysis to investigate regulatory effects of toluhydroquinone on expression of inducible nitric oxide synthase (iNOS), cyclooxyganse-2 (COX-2), nuclear factor-κB (NF-κB), Akt and mitogen-activated protein kinases (MAPKs) in LPS-stimulated RAW264.7 cells. The translocation of NF-κB was detected by immunofluorescence staining.

Key findings

Toluhydroquinone inhibited production of NO and PGE2 via suppressing protein expression of iNOS and COX-2, respectively. Secretion and expression of inflammatory cytokines were down-regulated by toluhydroquinone as well. Toluhydroquinone reduced phosphorylation of Akt, NF-κB and MAPKs. Moreover, toluhydroquinone inhibited translocation of NF-κB from the cytosol into the nucleus.

Conclusions

We revealed that inhibitory effects of toluhydroquinone on expression of inflammatory mediators are induced through inactivation of Akt, NF-κB and MAPKs. Thus, our results suggest that toluhydroquinone may be used for a potential anti-inflammatory reagent.