Anti-tumor actions of major component 3′-O-acetylhamaudol of Angelica japonica roots through dual actions, anti-angiogenesis and intestinal intraepithelial lymphocyte activation

Structure-Activity Relationship Studies on VEGFR2 Tyrosine Kinase Inhibitors for Identification of Potential Natural Anticancer Compounds

BACKGROUND

Over-expression of Vascular Endothelial Growth Factor Receptors (VEGFRs) leads to the hyperactivation of oncogenes. For inhibition of this hyperactivation, the USA Food Drug Administration (FDA) has approved many drugs that show adverse effects, such as hypertension, hypothyroidism, etc. There is a need to discover potent natural compounds that show minimal side effects. In the present study, we have taken structurally diverse known VEGFR2 inhibitors to develop a Quantitative Structure-Activity Relationship (QSAR) model and used this model to predict the inhibitory activity of natural compounds for VEGFR2.

METHODS

The QSAR model was developed through the forward stepwise Multiple Linear Regression (MLR) method. A developed QSAR model was used to predict the inhibitory activity of natural compounds. Absorption, Distribution, Metabolism, Excretion, and Toxicity (ADMET) assessment and molecular docking studies were performed. The binding stability of the natural compounds with VEGFR2 was elucidated through Molecular Dynamics (MD) simulation.

RESULTS

The developed QSAR model against VEGFR2 showed the regression coefficient of the training dataset (r2) as 0.81 and the external regression coefficient of the test dataset (r2 test) 0.71. Descriptors, viz., electro-topological state of potential hydrogen bonds (maxHBint2, nHBint6), atom types (minssNH), maximum topological distance matrix (SpMAD_Dt), and 2D autocorrelation (ATSC7v), have been identified. Using this model, 14 natural compounds have been selected that have shown inhibitory activity for VEGFR2, of which six natural compounds have been found to possess a strong binding affinity with VEGFR2. In MD simulation, four complexes have shown binding stability up to 50ns.

CONCLUSION

The developed QSAR model has identified 5 conserved activity-inducing physiochemical properties, which have been found to be correlated with the anticancer activity of the nonidentical ligand molecules bound with the VEGFR2 kinase. Lavendustin_A, 3'-O-acetylhamaudol, and arctigenin have been obtained as possible lead natural compounds against the VEGFR2 kinase.

Saposhnikovia divaricata root and its major components ameliorate inflammation and altered gut microbial diversity and compositions in DSS-induced colitis

Background

The root of Saposhnikovia divaricata (Turcz.) Schischk is a well-known traditional medicinal plant, containing various bioactive compounds with anti-inflammatory, antioxidant, and analgesic properties. However, no scientific studies have validated its clinical use as an anti-inflammatory agent against inflammatory bowel disease (IBD). This study aimed to investigate whether the root extract of S. divaricata ameliorates IBD and induces gut microbial alteration, using a RAW 264.7 cell line and a DSS-induced colitis mouse model.

Methods

To investigate the anti-inflammatory effects and alleviation of IBD, using a methanol extract of Saposhnikovia divaricata (Turcz.) Schischk. root (MESD), RAW 264.7, murine macrophages and a dextran sodium sulfate (DSS)-induced colitis mouse model were employed. 16S rRNA gene sequencing was conducted to determine the alterations in the gut microbiota of mice with DSS-induced colitis.

Results

MESD significantly decreased nitric oxide (NO) and inflammatory cytokine levels in lipopolysaccharide (LPS)-induced RAW 264.7 cells in vitro. Oral administration of MESD reduced the expression of inflammatory cytokines in the colons of mice with DSS-induced colitis. Additionally, MESD inhibited the abundance of Clostridium sensu stricto 1 and enhanced the predicted functional pathways, including l-glutamate degradation VIII (to propanoic acid). Seven compounds with anti-inflammatory properties were isolated from the MESD. Among them, 3'-O-acetylhamaudol and 3'-O-angeloylhamaudol exhibited strong anti-inflammatory effects in vitro.

Conclusion

Overall, MESD may be a potential natural product for the treatment of IBD by lowering inflammatory cytokine levels and altering gut microbiota composition.

Structure-activity relationships of natural quinone vegfrecine analogs with potent activity against VEGFR-1 and -2 tyrosine kinases

A series of analogs of vegfrecine, a natural quinone vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitor, was synthesized via oxidative amination of 2,5-dihydroxybenzamide with functionalized arylamine followed by ammonolysis and substitution of the quinone ring. The inhibitory activities of the analogs against the VEGFR-1 and -2 tyrosine kinases were assayed in vitro with the aim to identify a compound suitable to treat cancer and inflammatory diseases. Alterations of the functionality of the phenyl group, substitution of the quinone ring, and oxidative cyclization of the 1-carboxamide-2-aminoquinone moiety to form an isoxazole quinone ring were examined. Introduction of halo- and alkyl-substituents at the 5'-position of the phenyl ring resulted in potent inhibition of the VEGFR-1 and -2 tyrosine kinases. In particular, structural modification at C-5' on the phenyl ring was shown to significantly affect the selectivity of the inhibition between the VEGFR-1 and -2 tyrosine kinases. Compound 8, 5'-methyl-vegfrecine, showed superior selectivity toward the VEGFR-2 tyrosine kinase over the VEGFR-1 tyrosine kinase.

Tyrosine kinase inhibitors and their unique therapeutic potentialities to combat cancer

Cancer is one of the leading causes of death with a mortality rate of 12%. Although significant progress has been achieved in cancer research, the effective treatment of cancer remains the greatest global challenge in medicine. Dysregulation of tyrosine kinases (TK) is one of the characteristics of several types of cancers. Thus, drugs that target and inhibit these enzymes, known as TK inhibitors (TKIs), are considered vital chemotherapeutics to combat various types of cancer. The oral bioavailability of available TKIs and their targeted therapy are their potential benefits. Based on these characteristics, most TKIs are included in first/second-line therapy for the treatment of different cancers. This review aims to shed light on orally-active TKIs (natural and synthetic molecules) and their promising implication in the therapy of numerous types of tumors along with their mechanisms of action. Further, recent progress in the development of synthetic and isolation of natural TKIs is reviewed. A significant growth in research regarding the development of new-generation TKIs is made with time (23 FDA-approved TKIs from 2018) due to their better therapeutic response. Oral bioavailability should be considered as an important parameter while developing of new-generation TKIs; however, drug delivery systems can also be used to address issue of poor bioavailability to a certain extent. Moreover, clinical trials should be designed in consideration of the development of resistance and tumor heterogeneity.

Natural products as important tyrosine kinase inhibitors

As an important source of drugs, natural products play an important role in the discovery and development of new drugs. More than 60% of anti-tumor drugs are closely related to natural products. At the same time, as the main cause of tumors, the abnormal activity of tyrosine kinase has become an important target for clinical treatment. Although, small molecule targeted drugs dominate the cancer treatment. Natural active products are driving the development of new tyrosine kinase inhibitors with their unique mode of action and molecular structure diversity. Obtaining new chemical entities with tyrosine kinase inhibitory activity from natural active products will bring new breakthroughs in the research of anticancer drugs. In this paper, different tyrosine kinases are mainly classified as targets, and natural products and derivatives which have been found to inhibit tyrosine kinase activity have been described. It is hoped that by analyzing the different aspects of the source, structural characteristics, mechanism of action and biological activity of these natural products, we will find new members that can be developed into drugs and promote the development of anti-tumor drugs.

Angelica keiskei, an emerging medicinal herb with various bioactive constituents and biological activities

Angelica keiskei (Miq.) Koidz. (Umbelliferae) has traditionally been used to treat dysuria, dyschezia, and dysgalactia as well as to restore vitality. Recently, the aerial parts of A. keiskei have been consumed as a health food. Various flavonoids, coumarins, phenolics, acetylenes, sesquiterpene, diterpene, and triterpenes were identified as the constituents of A. keiskei. The crude extracts and pure constituents were proven to inhibit tumor growth and ameliorate inflammation, obesity, diabetics, hypertension, and ulcer. The extract also showed anti-thrombotic, anti-oxidative, anti-hyperlipidemic, anti-viral, and anti-bacterial activities. This valuable herb needs to be further studied and developed not only to treat these human diseases but also to improve human health. Currently A. keiskei is commercialized as a health food and additives in health drinks. This article presents a comprehensive review of A. keiskei and its potential place in the improvement of human health.

Sinodielide A exerts thermosensitizing effects and induces apoptosis and G2/M cell cycle arrest in DU145 human prostate cancer cells via the Ras/Raf/MAPK and PI3K/Akt signaling pathways

Sinodielide A (SA) is a naturally occurring guaianolide, which is isolated from the root of Sinodielsia yunnanensis. This root, commonly found in Yunnan province, is used in traditional Chinese medicine as an antipyretic, analgesic and diaphoretic agent. A number of studies have reported that agents isolated from a species of Umbelliferae (Apiaceae) have antitumor activities. We previously reported, using combined treatments with this medicinal herb and hyperthermia at various temperatures, an enhanced cytotoxicity in the human prostate cancer androgen‑independent cell lines, PC3 and DU145, and analyzed the related mechanisms. In the present study, we investigated the effects of treatment with SA prior to hyperthermia on the thermosensitivity of DU145 cells, and the mechanisms related to the induction of apoptosis and G(2)/M cell cycle arrest via the activation of extracellular-regulated kinase (ERK)1/2, c-Jun N-terminal kinase (JNK) mitogen-activated protein kinase (MAPK) signaling pathways, as well as the phosphoinositide 3-kinase (PI3K)/Akt signaling pathways. Cells were exposed to hyperthermia alone (40-44˚C) or hyperthermia in combination with SA. Lethal damage to cells treated with mild hyperthermia (40 or 42˚C) for up to 6 h was slight; however, hyperthermia in combination with SA synergistically enhanced thermosensivity. Lethal damage to cells treated with acute hyperthermia (43 or 44˚C) was more severe, but these effects were also enhanced and were more significant by the combined treatment with SA. The kinetics of apoptosis induction and cell cycle distribution were analyzed by flow cytometry. In addition, the levels of ERK1/2, JNK and Akt were determined by western blot analysis. The incidence of apoptotic cells after treatment with SA (20.0 µM) at 37˚C for 4 h, hyperthermia (44˚C) alone for 30 min, and the combination in sequence were examined. The sub-G1 division (%) in the diagram obtained by flow cytometry was applied to that assay. The percentage of apoptotic cells (10.53±5.02%) was higher at 48 h as compared to 0, 12 and 24 h after treatment. The distribution of DU145 cells in the G2/M cell cycle phase was markedly increased after 24 h of heating at 44˚C and after the combined treatment with heating and SA. The phosphorylation of ERK1/2 was reduced following treatment with heating and SA, while the levels of phosphorylated JNK (p-JNK) were markedly increased immediately after heating at 44˚C and when heating was combined with SA. By contrast, the levels of phosphorylated Akt (p-Akt) were immediately increased only after heating at 44˚C. Thus, we concluded that SA exerts its thermosensitizing effects on DU145 cells by inhibiting the activation of the MAPK/ERK1/2 and PI3K/Akt signaling pathways.

Treatment with Tie2-siRNA in combination with carboplatin suppresses the growth of Ishikawa human endometrial carcinoma cell xenografts in vivo

It is well-known that tumor angiogenesis is important in cancer development, and studies on blocking angiogenesis to treat tumors have become one of the most promising and active fields in anticancer research. The present study investigated the effect of siRNA targeting the tyrosine kinase receptor 2 (Tie2) gene in combination with carboplatin in a mouse model of endometrial carcinoma in an attempt to elucidate the role of Tie2 in the carcinogenesis and progression of endometrial carcinoma via angiogenesis, in order to establish a basis for the development of complementary molecule targeting and chemotherapeutic actions. Ishikawa cells were used to establish a human endometrial carcinoma nude mouse tumor xenograft model. Tie2-siRNA (20 μg/mouse) and/or carboplatin (25.0 mg·kg⁻¹) were administered as the treatment strategy. Real-time PCR and western blotting were used to evaluate the expression levels of Tie2 mRNA and protein and immunohistochemistry was used to assess the vessel density of the tumor tissues. The present data demonstrated that Tie2-siRNA and/or carboplatin were able to suppress the growth of endometrial xenografts in vivo and attenuate the expression of Tie2 mRNA and protein, as assessed by real-time PCR and western blotting. Furthermore, immunohistochemical assessment showed that the vessel density of the tumors decreased with treatment. The present results suggest that treatment with Tie2-siRNA or carboplatin alone was able to inhibit the growth of human endometrial carcinoma nude mouse xenografts markedly and decrease the expression of Tie2. The combination of Tie2-siRNA and carboplatin increased the therapeutic effect of carboplatin which may eliminate the tumor microenvironment, increase the apoptosis of tumor cells, normalize the abnormal tumor vessels and increase the efficiency of chemotherapy for endometrial carcinoma with carboplatin. The synergy of Tie2-siRNA in combination with carboplatin may involve the regulation of other angiogenesis and metastasis pathways.

Systems Biology in a Commercial Quality Study of the Japanese Angelica Radix: Toward an Understanding of Traditional Medicinal Plants

The commercial quality of Japanese Angelica radices — Angelica acutiloba Kitagawa (Yamato-toki) and A. acutiloba Kitagawa var. sugiyama Hikino (Hokkai-toki) — used in Kampo traditional herbal medicines, was studied by use of omics technologies. Complementary and alternative medical providers have observed in their clinical experience that differences in radix commercial quality reflect the differences in pharmacological responses; however, there has been little scientific examination of this phenomenon. The approach of omics, including metabolomics, transcriptomics, genomics, and informatics revealed a distinction between the radix-quality grades based on their metabolites, gene expression in human subjects, and plant genome sequences. Systems biology, constructing a network of omics data used to analyze this complex system, is expected to be a powerful tool for enhancing the study of radix quality and furthering a comprehensive understanding of all medicinal plants.

Chalcones isolated from Angelica keiskei and their inhibition of IL-6 production in TNF-α-stimulated MG-63 cell

Six chalcone compounds, 2',4',4-trihydroxy-3'-[2-hydroxy-7-methyl-3-methylene-6-octaenyl]chalcone (1), 2',4',4-trihydroxy-3'-geranylchalcone (2), 2',4',4-trihydroxy-3'-[6-hydroxy-3,7-dimethyl-2,7-octadienyl]chalcone (3), 2',4-dihydroxy-4'-methoxy-3'-[2-hydroperoxy-3-methyl-3-butenyl]chalcone (4), 2',4-dihydroxy-4'-methoxy-3'-geranylchalcone (5), and 2',4-dihydroxy-4'-methoxy-3'-[3-methyl-3-butenyl]chalcone (6) were isolated from the leaves of Angelica keiskei K (Umbelliferae). The structure of each isolated compound was determined using spectroscopic methods. Among the isolates, compounds 1-3 appeared to have potent inhibitory activity of IL-6 production in TNF-α-stimulated MG-63 cell, while compounds 4-6 did not. The distinct structural difference between compounds 1-3 and 4-6 was the presence of C-4' hydroxyl group in the chalcone moiety. Our results imply that the inhibitory activity of IL-6 production in TNF-α-stimulated MG-63 cell may be affected by the presence of C-4' hydroxyl group in the chalcone moiety.

Effectiveness and safety of bevacizumab for unresectable non-small-cell lung cancer: a meta-analysis

BACKGROUND

Non-small-cell lung cancer (NSCLC) accounts for more than 85% of all cases of lung cancer. The 5-year survival of patients presenting with advanced stage NSCLC is less than 15%, indicating that additional treatment options are needed. Bevacizumab is a recombinant humanized version of the murine anti-human vascular endothelial growth factor (VEGF) monoclonal antibody with a high binding specificity for VEGF.

OBJECTIVE

The aim of this meta-analysis was to evaluate the effectiveness and safety of bevacizumab in patients with unresectable non-small-cell lung cancer (NSCLC) on the basis of evidence-based methodology.

METHODS

The electronic database PubMed was searched to identify randomized, controlled trials (RCTs) of bevacizumab for the treatment of unresectable NSCLC. Other databases such as the Cochrane Library Trials Register, the WHO Trial Registration, the National Cancer Institute, ClinicalTrials.gov, the European Organization for Research and Treatment of Cancer, the Southwest Oncology Group, the Eastern Cooperative Oncology Group, the European Society of Clinical Oncology and the American Society of Clinical Oncology were also searched. The meta-analysis was performed using Reviewer Manager Version 5.0 software provided by the Cochrane Collaboration. Outcome measures were overall survival rates, progression-free survival, tumour response rate, incidence of severe adverse events (SAEs) and treatment-related death.

RESULTS

Four eligible studies that included 2101 patients were found; in these studies, bevacizumab was administered to 1237 patients. Neither high-dose (15 mg/kg) nor low-dose (7.5 mg/kg) bevacizumab increased 1-year overall survival rates compared with patients not treated with bevacizumab. However, high-dose bevacizumab, rather than low-dose, increased 2-year overall survival rate (risk ratio [RR] = 1.24; 95% confidence interval [CI] 1.04, 1.49) and tumour response rate (RR = 1.69; 95% CI 1.21, 2.35) compared with patients not treated with bevacizumab. Progression-free survival was also significantly improved in both the low- (hazard ratio [HR] = 0.76; 95% CI 0.64, 0.90) and high-dose groups (HR = 0.73; 95% CI 0.65, 0.81). There was a clear and significant increase in the rate of treatment-related death in the high-dose group (RR = 2.07; 95% CI 1.19, 3.59) compared with patients not treated with bevacizumab. No significant differences were noted in the rate of treatment-related death in the low-dose group or in the incidences of SAE in the low- or high-dose groups compared with patients not treated with bevacizumab. Neutropenia was easily induced in both the low- and high-dose bevacizumab groups. Patients who received high-dose bevacizumab tended to experience hypertension, neutropenia, haemoptysis, rash and headache more frequently than patients not treated with bevacizumab.

CONCLUSIONS

Low-dose bevacizumab may significantly improve progression-free survival in patients with unresectable NSCLC, whereas high-dose bevacizumab may increase 2-year overall survival rates, prolong progression-free survival and improve tumour response rate but at the cost of higher treatment-related death. Larger well designed RCTs should be carried out in the future to clarify the role of bevacizumab in the treatment of NSCLC.

Eukaryotic expression of extracellular ligand binding domains of murine Tie-2 and its anti-angiogenesis effect in SGC-7901 cell lines

BACKGROUND AND AIMS

Researches about blocking angiogenesis to treat tumor have become one of the most promising and active fields in anticancer research. This study aimed to investigate the eukaryotic expression of extracellular ligand binding domains of murine Tie-2 and its anti-angiogenesis effect.

METHODS

A eukaryotic expression vector pcDNA3.1(+) integrating with a DNA fragment which encode extracellular ligand binding domains of murine Tie-2 was transfected into SGC-7901 gastric cancer cell line. The protein expression was detected by western blot analysis and immunocytochemistry staining. Following the construction of nude mouse tumor xenograft model with and without transfected cells, tumor microvessel density was determined by counting per high power field in the sections stained with an antibody to CD31 to test its inhibition of angiogenesis.

RESULTS

The extracellular ligand binding domains of murine Tie-2 receptor was highly expressed in SGC-7901 gastric cancer cells with plasmid transfection. The mean tumor sizes of groups with and without transfection were 1.27 +/- 0.35 and 1.75 +/- 0.17 cm(3), respectively (P = 0.025). The mean inhibitory rate of tumor was 27.18 +/- 19.93%. The comparison between highest microvessel density of group with transfection (14.00 +/- 3.80) and that of group without transfection (22.30 +/- 5.91) was statistically significant at P = 0.030.

CONCLUSION

The protein of extracellular ligand binding domains of murine Tie-2 can be expressed at high level in the eukaryotic expression system, and the expressed protein may have the anti-angiogenesis effect.

Dihydrofurochromones from Prionosciadium thapsoides

Chemical investigations of Prionosciadium thapsoides roots led to the isolation of the new dihydrofurochromones (S)-(+)-4'-O-angeloyl-5-O-methylvisamminol (1) and (S)-(+)-4'-O-senecioyl-5-O-methylvisamminol (2), together with the known coumarins jatamansin, buchtormin, isopteryxin, isosamidin, psoralen, and bergapten. The structures of 1 and 2 were determined by 1D and 2D NMR experiments, and their absolute configuration was established by chemical correlation with (+)-5-O-methylvisamminol (3), whose structure was secured by single-crystal X-ray diffraction analysis and its absolute configuration was established as S by vibrational circular dichroism spectroscopy in comparison to DFT B3LYP/DGDZVP calculations.