Effects of brucine on vascular endothelial growth factor expression and microvessel density in a nude mouse model of bone metastasis due to breast cancer

Phytochemicals Showing Antiangiogenic Effect in Pre-clinical Models and their Potential as an Alternative to Existing Therapeutics

Angiogenesis, the formation of new blood vessels from a pre-existing vascular network, is an important hallmark of several pathological conditions, such as tumor growth and metastasis, proliferative retinopathies, including proliferative diabetic retinopathy and retinopathy of prematurity, age-related macular degeneration, rheumatoid arthritis, psoriasis, and endometriosis. Putting a halt to pathology-driven angiogenesis is considered an important therapeutic strategy to slow down or reduce the severity of pathological disorders. Considering the attrition rate of synthetic antiangiogenic compounds from the lab to reaching the market due to severe side effects, several compounds of natural origin are being explored for their antiangiogenic properties. Employing pre-clinical models for the evaluation of novel antiangiogenic compounds is a promising strategy for rapid screening of antiangiogenic compounds. These studies use a spectrum of angiogenic model systems that include HUVEC two-dimensional culture, nude mice, chick chorioallantoic membrane, transgenic zebrafish, and dorsal aorta from rats and chicks, depending upon available resources. The present article emphasizes the antiangiogenic activity of the phytochemicals shown to exhibit antiangiogenic behavior in these well-defined existing angiogenic models and highlights key molecular targets. Different models help to get a quick understanding of the efficacy and therapeutics mechanism of emerging lead molecules. The inherent variability in assays and corresponding different phytochemicals tested in each study prevent their immediate utilization in clinical studies. This review will discuss phytochemicals discovered using suitable preclinical antiangiogenic models, along with a special mention of leads that have entered clinical evaluation.

Chemical constituents, pharmacological action, antitumor application, and toxicity of Strychnine Semen from Strychnons pierriana A.W.Hill.: A review

ETHNOPHARMACOLOGICAL RELEVANCE

The dried and mature seeds of Strychnons pierriana A.W.Hill. have been called Strychnine Semen(S. Semen). It have been used in traditional Chinese medicine for nearly 400 years. In recent decades, scholars at home and abroad have widely used S. Semen in the treatment of tumor diseases, showing good anti-tumor effects. In this paper, the modern research achievements of S. Semen are reviewed, including traditional uses, phytochemistry, pharmacology, and toxicology.

AIM OF THE STUDY

In recent years, the research on S. Semen has increased gradually, especially the research on its anti-tumor. This paper not only reviewed the traditional uses, chemical constituents and pharmacological activities of S. Semen, but also comprehensively listed the mechanisms of Strychnos in the treatment of different tumors, providing a review for further research and development of Strychnos resources.

MATERIALS AND METHODS

A systematic review of the literature on Fuzi was performed using several resources, namely classic books on Chinese herbal medicine and various scientific databases, such as PubMed, the Web of Science, and the China Knowledge Resource Integrated databases.

RESULTS

The main constituents of S. Semen include alkaloids, terpenoids, steroids, and their glycosides. Modern studies have proved that S. Semen has a wide range of pharmacological effects, including anti-inflammatory and analgesic, anti-thrombotic, myocardial cell protection, immune regulation, nerve excitation, and anti-tumor effects. Among them, the anti-tumor effect has been the focus of research in recent years. S. Semen have a certain therapeutic effect on many kinds of tumors, such as liver cancer, colon cancer, and stomach cancer in the digestive system, breast, cervical, and ovarian cancer in the reproductive system, myeloma and leukemia in the blood system, and those in the nervous system and the immune system.

CONCLUSION

Strychnine has an inhibitory effect on a variety of tumors. However, modern studies of strychnine are incomplete, and more in-depth studies are needed on its stronger bioactive constituents and potential pharmacological effects. The antitumor effect of Strychnine is worth further exploration.

Network toxicology and molecular docking analyses on strychnine indicate CHRM1 is a potential neurotoxic target

Background

Improper use of strychnine can cause death. The aim of this study was to identify and evaluate toxic mechanisms of action associated with active compounds in strychnine using a network toxicology approach, and explore potential pathogenic targets.

Methods

In the present study, strychnine target and central nervous system-related gene set were established using the Traditional Chinese Medicine Systems Pharmacology (TCMSP) database and four disease gene databases (Genecards, OMIM, PharmGkb, TTD). An “ingredient-target” interactive active network map was constructed using Cytoscape software (version 3.8.0). Functional enrichment analysis was performed based on the hub genes. A protein-protein interaction network was constructed using STRING database. The pharmacokinetics (ADMET) properties of strychnine were evaluated using SwissADME tool. Molecular docking was performed using Autodock Vina to explore the interactions between the active compounds and the target protein.

Results

Five strychnine toxicity-related components and a gene set of 40 genes were obtained. GO and KEGG analyses showed that Strychnine acts on the central nervous system through G protein-coupled receptor signaling pathway. Analysis of “ADMET” related parameters showed a high gastrointestinal tract absorption of (S)-stylopine and isobrucine and the compounds could cross the blood brain barrier. CHRM1 was selected as a key gene in strychnine toxicity. Molecular docking results showed that the co-crystalized ligands did not form hydrogen bond with CHRM1. (S)-stylopine had the highest binding affinity (binding energy = − 8.5 kcal/mol) compared with the other two compounds.

Conclusion

Network toxicology and molecular docking reveal the toxicity mechanisms of strychnine active compounds. The findings showed that CHRM1 is a potential neurotoxic target. (S)-stylopine showed stronger neurotoxic effect compared with the other ligands.

Shifts in Fecal Metabolite Profiles Associated With Ramadan Fasting Among Chinese and Pakistani Individuals

The human gut microbiota has been proposed to serve as a multifunctional organ in host metabolism, contributing effects to nutrient acquisition, immune response, and digestive health. Fasting during Ramadan may alter the composition of gut microbiota through changes in dietary behavior, which ultimately affects the contents of various metabolites in the gut. Here, we used liquid chromatography–mass spectrometry-based metabolomics to investigate the composition of fecal metabolites in Chinese and Pakistani individuals before and after Ramadan fasting. Principal component analysis showed distinct separation of metabolite profiles among ethnic groups as well as between pre- and post-fasting samples. After Ramadan fasting, the Chinese and Pakistani groups showed significant differences in their respective contents of various fecal metabolites. In particular, L-histidine, lycofawcine, and cordycepin concentrations were higher after Ramadan fasting in the Chinese group, while brucine was enriched in the Pakistani group. The KEGG analysis suggested that metabolites related to purine metabolism, 2-oxocarboxylic acid metabolism, and lysine degradation were significantly enriched in the total subject population pre-fasting vs. post-fasting comparisons. Several bacterial taxa were significantly correlated with specific metabolites unique to each ethnic group, suggesting that changes in fecal metabolite profiles related to Ramadan fasting may be influenced by associated shifts in gut microbiota. The fasting-related differences in fecal metabolite profile, together with these group-specific correlations between taxa and metabolites, support our previous findings that ethnic differences in dietary composition also drive variation in gut microbial composition and diversity. This landscape view of interconnected dietary behaviors, microbiota, and metabolites contributes to the future development of personalized, diet-based therapeutic strategies for gut-related disorders.

Strychnine and its mono- and dimeric analogues: a pharmaco-chemical perspective

Covering: up to November 2021Since its isolation in 1818, strychnine has attracted the attention of a plethora of chemists and pharmacologists who have established its structure, developed total syntheses, and examined its complex pharmacology. While numerous reviews on structure elucidation and total synthesis of strychnine are available, reports on structure-activity relationships (SARs) of this fascinating alkaloid are rare. In this review, we present and discuss structures, synthetic approaches, metabolic transformations, and the diverse pharmacological actions of strychnine and its mono- and dimeric analogues. Particular attention is given to its SARs at glycine receptors (GlyRs) in light of recently published high-resolution structures of strychnine-GlyR complexes. Other pharmacological actions of strychnine and its derivatives, such as their antagonistic properties at nicotinic acetylcholine receptors (nAChRs), allosteric modulation of muscarinic acetylcholine receptors as well as anti-cancer and anti-plasmodial effects are also critically reviewed, and possible future developments in the field are discussed.

Brucine-loaded transliposomes nanogel for topical delivery in skin cancer: statistical optimization, in vitro and dermatokinetic evaluation

The aim of the present study was to develop, optimize brucine-loaded transliposomes (BRC-TL) formulation for dermal delivery of brucine for skin cancer. The BRC-TL formulations were evaluated for vesicle size, entrapment efficiency, and in vitro drug release. The optimized formulation was further evaluated for skin penetration by confocal laser microscopy and dermatokinetic study. The optimized BRC-TL formulation presented sealed lamellar shaped vesicles, with vesicles size, polydispersity index, entrapment efficiency, and in vitro drug release of 136.20 ± 2.87 nm, 0.354 ± 0.02, 86.01 ± 1.27%, and 83.09 ± 2.07%, respectively. Ex vivo permeation study showed that, developed BRC-TL formulation had a 2.4-fold increment in permeation as compared to BRC suspension. Texture analysis showed that the BRC-TL gel presented firmness of 158.91 g, consistency of 615.03 g/s, cohesiveness of  - 115.26 g and a viscosity index of  - 472.05 g/s. The confocal images of rat skin clearly showed the deeper penetration of rhodamine B-loaded TL formulation as compared to the Rhodamine B-hydro alcoholic solution. The optimized BRC-TL formulation demonstrated significantly higher cytotoxicity than placebo liposome and BRC suspension (P < 0.05). Further, the BRC-TL nanogel treated rat skin showed a substantial increase in C_{Skin max} and AUC_0-8 in comparison to rat skin treated with BRC conventional gel (P < 0.05). The data revealed that the developed TLs formulation could be a promising drug nanocarrier for brucine dermal delivery in the treatment of skin cancer.

Brucine: A Review of Phytochemistry, Pharmacology, and Toxicology

Brucine, a weak alkaline indole alkaloid, is one of the main bioactive and toxic constituents of Nux-vomica. Modern pharmacology studies and clinical practice demonstrate that brucine possesses wide pharmacological activities, such as anti-tumor, anti-inflammatory, analgesic, and the effects on cardiovascular system and nervous system, etc. However, its central nervous system toxicity severely limits its clinical application. Herein, the physicochemical properties, pharmacological activities, and toxicity of brucine were reviewed, and the novel strategies to address the toxicity issues were discussed, aiming to bring new insights into further research and application of this active component.

Anti-Angiogenic Effects of Phytochemicals on miRNA Regulating Breast Cancer Progression

Several phytochemicals have been identified for their role in modifying miRNA regulating tumor progression. miRNAs modulate the expression of several oncogenes and tumor suppressor genes including the genes that regulate tumor angiogenesis. Hypoxia inducible factor-1 alpha (HIF-1α) signaling is a central axis that activates oncogenic signaling and acts as a metabolic switch in endothelial cell (EC) driven tumor angiogenesis. Tumor angiogenesis driven by metabolic reprogramming of EC is crucial for tumor progression and metastasis in many different cancers, including breast cancers, and has been linked to aberrant miRNA expression profiles. In the current article, we identify different miRNAs that regulate tumor angiogenesis in the context of oncogenic signaling and metabolic reprogramming in ECs and review how selected phytochemicals could modulate miRNA levels to induce an anti-angiogenic action in breast cancer. Studies involving genistein, epigallocatechin gallate (EGCG) and resveratrol demonstrate the regulation of miRNA-21, miRNA-221/222 and miRNA-27, which are prognostic markers in triple negative breast cancers (TNBCs). Modulating the metabolic pathway is a novel strategy for controlling tumor angiogenesis and tumor growth. Cardamonin, curcumin and resveratrol exhibit their anti-angiogenic property by targeting the miRNAs that regulate EC metabolism. Here we suggest that using phytochemicals to target miRNAs, which in turn suppresses tumor angiogenesis, should have the potential to inhibit tumor growth, progression, invasion and metastasis and may be developed into an effective therapeutic strategy for the treatment of many different cancers where tumor angiogenesis plays a significant role in tumor growth and progression.

Antiangiogenic Effect of Alkaloids

Alkaloids are among the natural phytochemicals contained in functional foods and nutraceuticals and have been suggested for the prevention and/or management of oxidative stress and inflammation-mediated diseases. In this review, we aimed to describe the effects of alkaloids in angiogenesis, the process playing a crucial role in tumor growth and invasion, whereby new vessels form. Antiangiogenic compounds including herbal ingredients, nonherbal alkaloids, and microRNAs can be used for the control and treatment of cancers. Several lines of evidence indicate that alkaloid-rich plants have several interesting features that effectively inhibit angiogenesis. In this review, we present valuable data on commonly used alkaloid substances as potential angiogenic inhibitors. Different herbal and nonherbal ingredients, introduced as antiangiogenesis agents, and their role in angiogenesis-dependent diseases are reviewed. Studies indicate that angiogenesis suppression is exerted through several mechanisms; however, further investigations are required to elucidate their precise molecular and cellular mechanisms, as well as potential side effects.

Brucine Suppresses Vasculogenic Mimicry in Human Triple-Negative Breast Cancer Cell Line MDA-MB-231

Vasculogenic mimicry (VM) with the pattern of endothelial independent tubular structure formation lined by aggressive tumor cells mimics regular tumor blood vessels to ensure robust blood supply and correlates with the proliferation, invasion, metastasis, and poor prognosis of malignant tumors, which was demonstrated to be a major obstacle for resistance to antiangiogenesis therapy. Therefore, it is urgent to discover methods to abrogate the VM formation of tumors, which possesses important practical significance for improving tumor therapy. Brucine is a traditional medicinal herb extracted from seeds of Strychnos nux-vomica L. (Loganiaceae) exhibiting antitumor activity in a variety of cancer models. In the present study, the effect of brucine on vasculogenic mimicry and the related mechanism are to be investigated. We demonstrated that, in a triple-negative breast cancer cell line MDA-MB-231, brucine induced a dose-dependent inhibitory effect on cell proliferation along with apoptosis induction at higher concentrations. The further study showed that brucine inhibited cell migration and invasion with a dose-dependent manner. Our results for the first time indicated that brucine could disrupt F-actin cytoskeleton and microtubule structure, thereby impairing hallmarks of aggressive tumors, like migration, invasion, and holding a possibility of suppressing vasculogenic mimicry. Hence, the inhibitory effect of brucine on vasculogenic mimicry was further verified. The results illustrated that brucine significantly suppressed vasculogenic mimicry tube formation with a dose-dependent effect indicated by the change of the number of tubules, intersections, and mean length of tubules. The in-depth molecular mechanism of vasculogenic mimicry suppression induced by brucine was finally suggested. It was demonstrated that brucine inhibited vasculogenic mimicry which might be through the downregulation of erythropoietin-producing hepatocellular carcinoma-A2 and matrix metalloproteinase-2 and metalloproteinase-9.

Biochemical studies evaluating the chemopreventive potential of brucine in chemically induced mammary carcinogenesis of rats

The present study was aimed to investigate the dose dependent chemopreventive activity of brucine against 7, 12-dimethylbenz (a) anthracene induced mammary gland tumorigenesis in rats. The mammary tumor was induced by a single dose of DMBA (25 mg/rat) injected subcutaneously near the mammary gland. We observed reduced body weight and increase in tumor incidence, the total number of tumors, and tumor volume in DMBA alone injected rats and also observed decreased antioxidant status (SOD, CAT, GPX, and GSH) and increased lipid peroxidation (TBARS and LOOH) in plasma and mammary tissues. Increased levels of CYP450, Cyt-b5 and decreased levels of phase II (GST and GR) biotransformation enzymes were noticed in the liver and mammary tissues. Further, increased levels of lipid profile (TC, TG, PL, and FFA) and lipoprotein (LDL and VLDL) were noticed. Whereas, decrease in the levels of HDL in plasma and decreased levels of PL and FFA in mammary tissues were observed. Oral administration of brucine in different doses (2, 4 and 8 mg/kg bw) inhibited the tumor incidence and restored the levels of biochemical markers near to normal in dose responsive manner. Biochemical findings are supported by histopathological studies. The results suggest that brucine at a dose of 8 mg/kg bw shows more significant chemopreventive activity in DMBA-induced mammary carcinogenesis.

Effects of Brucine on the OPG/RANKL/RANK Signaling Pathway in MDA-MB-231 and MC3T3-E1 Cell Coculture System

The present study examined the effects of brucine on the OPG/RANKL/RANK signaling pathway for exploring the mechanism of brucine suppression of bone metastasis in breast cancer. MDA-MB-231 breast cancer cells and mouse osteoblast MC3T3-E1 cells were cocultured to mimic the breast cancer bone metastasis microenvironment in vitro. qRT-PCR and Western blotting were used to detect the expressions of OPG and RANKL at the mRNA and protein levels, respectively, in brucine-treated cultures and they were compared to those in untreated cultures. We aimed to understand the effect of brucine on the entire OPG/RANKL/RANK signaling pathway after analyzing these effects. Results showed that brucine treatment significantly increased both the OPG mRNA/RANKL mRNA expression ratio and the OPG protein/RANKL protein ratio in cocultures compared to those in untreated cocultures (P < 0.01). Brucine, therefore, plays a regulatory role in the OPG/RANKL/RANK signaling pathway, suggesting that it can indirectly control osteoclasts by regulating the expression and secretion of OPG and RANKL in osteoblast cells, thereby inhibiting the differentiation and bone resorption function of osteoclasts.

Brucine suppresses breast cancer metastasis via inhibiting epithelial mesenchymal transition and matrix metalloproteinases expressions

OBJECTIVE

To examine the effect of brucine on the migration, invasion, adhesion and expressions of epithelial-to-mesenchymal transition (EMT) markers and matrix metalloproteinases (MMPs) in the highly metastatic breast cancer cell lines MDA-MB-231 and Hs578-T.

METHODS

MDA-MB-231 and Hs578-T cells were divided to 4 groups: the control group (0.1% DMSO), and 25, 50 and 100 μmol/L brucine groups. The cell viability was determined using a CellTiter-Glo® luminescent cell viability. The scratch wound healing assay and tanswell migration assay were used to determine the migration ability of these cells treated by different concentrations of brucine. The proliferation rate, invasive potential and adhesive ability were respectively performed by colony formation assay, transwell invasion assay and adhension assay. The protein and mRNA expressions of EMT biomarkers, MMP-2 and MMP-9 were investigated by real-time reverse transcription polymerase chain reaction and Western blot.

RESULTS

Compared with the control group, brucine had little effect on cell viability or proliferation (P>0.05), but led to a dose-dependent decrease on migration, invasion, adhension of MDA-MB-231 and Hs578-T cells (P<0.01). Furthermore, brucine increased the protein and mRNA levels of EMT markers such as E-cadherin and β-catenin in MDA-MB-231 and Hs578-T cells, and decreased the protein and mRNA levels of mesenychmal markers such as vimentin and fibronectin, as well as the expressions of MMP-2 and MMP-9 (all P<0.01).

CONCLUSION

Brucine inhibited triple negative breast cancer cells metastasis potentially through EMT reversion and MMP-2 and MMP-9 inhibition.

Lipid composition has significant effect on targeted drug delivery properties of NGR-modified liposomes

The Asn-Gly-Arg (NGR) motif has previously been demonstrated to specifically bind to CD13, which is selectively overexpressed in tumor vasculature and some tumor cells (e.g. HT1080). It was reported that NGR-modified stealth liposomes (NGR-SL) could be prepared with different lipid composition, such as 1,2-dipalmitoyl-sn-glycero-phosphatidylcholine (DPPC), hydrogenated soy posphatidylcholine (HSPC) and soy posphatidylcholine (SPC). In the present study, NGR-modified liposomes were prepared with DPPC, HSPC, SPC or the mixture of HSPC and SPC. The resultant liposomes with different lipid composition were compared in terms of cell uptake, antitumor efficacy and targeted drug delivery efficiency using HT1080 tumor model. It was found that NGR-SL composed of the mixture of HSPC and SPC was able to improve targeted drug delivery efficiency to tumor producing the most significant antitumor activity. Collectively, the NGR-modified liposomes composed of the mixture of HSPC and SPC are promising carriers for the treatment of tumor. Besides NGR ligand, lipid composition could also significantly affect the targeted delivery efficiency to the tumor.

Brucine suppresses colon cancer cells growth via mediating KDR signalling pathway

Angiogenesis plays an important role in colon cancer development. This study aimed to demonstrate the effect of brucine on tumour angiogenesis and its mechanism of action. The anti-angiogenic effect was evaluated on the chicken chorioallantoic membrane (CAM) model and tube formation. The mechanism was demonstrated through detecting mRNA and protein expressions of VEGFR2 (KDR), PKCα, PLCγ and Raf1 by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot (WB), as well as expressions of VEGF and PKCβ and mTOR by ELISA and WB. The results showed that brucine significantly reduced angiogenesis of CAM and tube formation, inhibited the VEGF secretion and mTOR expression in LoVo cell and down-regulated the mRNA and phosphorylation protein expressions of KDR, PKCα, PLCγ and Raf1. In addition, the effects of brucine on KDR kinase activity, viability of LoVo cell and gene knockdown cell were detected with the Lance™ assay, WST-1 assay and instantaneous siRNA. Compared to that of normal LoVo cells, the inhibition on proliferation of knockdown cells by brucine decreased significantly. These results suggest that brucine could inhibit angiogenesis and be a useful therapeutic candidate for colon cancer intervention.

Jiedu Xiaozheng Yin, a Chinese herbal formula, inhibits tumor angiogenesis via downregulation of VEGF-A and VEGFR-2 expression in vivo and in vitro

Angiogenesis is crucial for cancer growth and metastasis and inhibition of angiogenesis has been recognized to be a promising strategy for the treatment of cancer. Traditional Chinese medicine (TCM) has been used for thousands of years to treat cancer. Jiedu Xiaozheng Yin (JXY), a polyherbal formula of TCM, has been used to treat various tumors in China. However, the mechanism of its anticancer activity has yet to be fully elucidated. Using human umbilical vein endothelial cells (HUVECs), chick chorioallantoic membrane (CAM) and a hepatoma mouse xenograft model, we investigated the underlying molecular mechanisms of ethanol extract of Jiedu Xiaozheng Yin (EE-JXY). EE-JXY treatment significantly inhibited tumor cell growth both in vitro and in the mouse xenograft model (P<0.05). Moreover, EE-JXY reduced tube formation of HUVECs and angiogenesis in the CAM (P<0.01) and microvessel density (MVD) of tumor in vivo (P<0.05). Further studies showed that EE-JXY was able to suppress the expression of vascular endothelial growth factor A (VEGF-A) and vascular endothelial growth factor receptor 2 (VEGFR-2) in both HepG2 cells and HUVECs (P<0.01) and in tumor (P<0.01). Thus, JXY suppressed tumor growth at least by inhibiting angiogenesis.