Deguelin--an inhibitor to tumor lymphangiogenesis and lymphatic metastasis by downregulation of vascular endothelial cell growth factor-D in lung tumor model

Deguelin Restores Paclitaxel Sensitivity in Paclitaxel-Resistant Ovarian Cancer Cells via Inhibition of the EGFR Signaling Pathway

Background

Ovarian cancer is one of women's malignancies with the highest mortality among gynecological cancers. Paclitaxel is used in first-line ovarian cancer chemotherapy. Research on paclitaxel-resistant ovarian cancer holds significant clinical importance.

Methods

Cell viability and flow cytometric assays were conducted at different time and concentration points of deguelin and paclitaxel treatment. Immunoblotting was performed to assess the activation status of key signaling molecules important for cell survival and proliferation following treatment with deguelin and paclitaxel. The fluo-3 acetoxymethyl assay for P-glycoprotein transport activity assay and cell viability assay in the presence of N-acetyl-L-cysteine were also conducted.

Results

Cell viability and flow cytometric assays demonstrated that deguelin resensitized paclitaxel in a dose- and time-dependent manner. Cotreatment with deguelin and paclitaxel inhibited EGFR and its downstream signaling molecules, including AKT, ERK, STAT3, and p38 MAPK, in SKOV3-TR cells. Interestingly, cotreatment with deguelin and paclitaxel suppressed the expression level of EGFR via the lysosomal degradation pathway. Cotreatment did not affect the expression and function of P-glycoprotein. N-acetyl-L-cysteine failed to restore cell cytotoxicity when used in combination with deguelin and paclitaxel in SKOV3-TR cells. The expression of BCL-2, MCL-1, and the phosphorylation of the S155 residue of BAD were downregulated. Moreover, inhibition of paclitaxel resistance by deguelin was also observed in HeyA8-MDR cells.

Conclusion

Our research showed that deguelin effectively suppresses paclitaxel resistance in SKOV3-TR ovarian cancer cells by downregulating the EGFR and its downstream signaling pathway and modulating the BCL-2 family proteins. Furthermore, deguelin exhibits inhibitory effects on paclitaxel resistance in HeyA8-MDR ovarian cancer cells, suggesting a potential mechanism for paclitaxel resensitization that may not be cell-specific. These findings suggest that deguelin holds promise as an anticancer therapeutic agent for overcoming chemoresistance in ovarian cancer.

Modulation of hypoxia-inducible factor-1 signaling pathways in cancer angiogenesis, invasion, and metastasis by natural compounds: a comprehensive and critical review

Tumor cells employ multiple signaling mediators to escape the hypoxic condition and trigger angiogenesis and metastasis. As a critical orchestrate of tumorigenic conditions, hypoxia-inducible factor-1 (HIF-1) is responsible for stimulating several target genes and dysregulated pathways in tumor invasion and migration. Therefore, targeting HIF-1 pathway and cross-talked mediators seems to be a novel strategy in cancer prevention and treatment. In recent decades, tremendous efforts have been made to develop multi-targeted therapies to modulate several dysregulated pathways in cancer angiogenesis, invasion, and metastasis. In this line, natural compounds have shown a bright future in combating angiogenic and metastatic conditions. Among the natural secondary metabolites, we have evaluated the critical potential of phenolic compounds, terpenes/terpenoids, alkaloids, sulfur compounds, marine- and microbe-derived agents in the attenuation of HIF-1, and interconnected pathways in fighting tumor-associated angiogenesis and invasion. This is the first comprehensive review on natural constituents as potential regulators of HIF-1 and interconnected pathways against cancer angiogenesis and metastasis. This review aims to reshape the previous strategies in cancer prevention and treatment.

Pharmacological basis and new insights of deguelin concerning its anticancer effects

Deguelin is a rotenoid of the flavonoid family, which can be extracted from Lonchocarpus, Derris, or Tephrosia. It possesses the inhibition of cancer cell proliferation by inducing apoptosis through regulating the phosphoinositide 3-kinase/protein kinase B (PI3K/Akt) signaling pathway, the NF-κB signaling pathway, the Wnt signaling pathway, the adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) signaling pathway and epidermal growth factor receptor (EGFR) signaling, activating the p38 mitogen-activated protein kinase (MAPK) pathway, repression of Bmi1, targeting cyclooxygenase-2 (COX-2), targeting galectin-1, promotion of glycogen synthase kinase-3β (GSK3β)/FBW7-mediated Mcl-1 destabilization and targeting mitochondria via down-regulating Hexokinases II-mediated glycolysis, PUMA-mediation, which are some crucial molecules which modulate closely cancer cell growth and metastasis. Deguelin inhibits tumor cell propagation and malignant transformation through targeting angiogenesis, targeting lymphangiogenesis, targeting focal adhesion kinase (FAK), inhibiting the CtsZ/FAK signaling pathway, targeting epithelial-mesenchymal transition (EMT), the NF-κB signaling pathway, regulating NIMA-related kinase 2 (NEK2). In addition, deguelin possesses other biological activities, such as targeting cell cycle arrest, modulation of autophagy, inhibition of hedgehog pathway, inducing differentiation of mutated NPM1 acute myeloid leukemia etc. Therefore, deguelin is a promising chemopreventive agent for cancer therapy.

Lymphatic metastasis-related TBL1XR1 enhances stemness and metastasis in gastric cancer stem-like cells by activating ERK1/2-SOX2 signaling

The poor prognosis of gastric cancer (GC) results largely from metastasis and chemotherapy resistance. Toward novel therapeutic strategies that target or evade these phenomena, we evaluated the function of the transcriptional regulator transducin (β)-like 1 X-linked receptor 1 (TBL1XR1) in GC cells, including stem-like cells. In this study, the correlation of expression of TBL1XR1 and clinical features and GC patients' outcomes was evaluated. Knockdown or exogenous expression of TBL1XR1 was combined with in vitro (2D and 3D cultures) and in vivo (mouse lung and lymphatic metastasis models) assays to evaluate the function of TBL1XR1. TBL1XR1's downstream signaling was delineated by phospho-kinase array and knockdown of candidate mediators. Analysis of clinical data showed that TBL1XR1 overexpression was correlated with worse prognosis. Functional assays showed that TBL1XR1 promoted stemness, epithelial-mesenchymal transition (EMT), and lung and lymphatic metastasis in GC cells. TBL1XR1 activated ERK1/2-Sox2 signaling and was dependent on signaling via PI3K/AKT, in GC stem-like cells distinguished by CD44 expression. Moreover, inhibition of these signaling proteins reversed chemoresistance in in vitro and in vivo models. Taken together, our results indicate that TBL1XR1 promotes stemness and metastasis in GC, making it a potential prognostic indicator. The PI3K/AKT-TBL1XR1-ERK1/2-Sox2 axis may represent a target for the treatment of GC.

Enantioselective dearomative [3 + 2] annulation of 3-hydroxy chromanones with azonaphthalenes

Enantioselective dearomative [3 + 2] annulation of 3-hydroxy chromanones with azonaphthalenes provided a large variety of chromanone fused indolines in moderate to good yields with generally good enantioselectivities.

Potential lymphangiogenesis therapies: Learning from current antiangiogenesis therapies-A review

In recent years, lymphangiogenesis, the process of lymphatic vessel formation from existing lymph vessels, has been demonstrated to have a significant role in diverse pathologies, including cancer metastasis, organ graft rejection, and lymphedema. Our understanding of the mechanisms of lymphangiogenesis has advanced on the heels of studies demonstrating vascular endothelial growth factor C as a central pro-lymphangiogenic regulator and others identifying multiple lymphatic endothelial biomarkers. Despite these breakthroughs and a growing appreciation of the signaling events that govern the lymphangiogenic process, there are no FDA-approved drugs that target lymphangiogenesis. In this review, we reflect on the lessons available from the development of antiangiogenic therapies (26 FDA-approved drugs to date), review current lymphangiogenesis research including nanotechnology in therapeutic drug delivery and imaging, and discuss molecules in the lymphangiogenic pathway that are promising therapeutic targets.

Deguelin exerts anticancer activity of human gastric cancer MGC-803 and MKN-45 cells in vitro

During the pathogenesis of gastric cancer, Akt signaling is considered as a pivotal inducer of gastric cancer development. Here we report the identification of anticancer activities of deguelin, a natural agent that inhibits Akt signaling. When applied to MGC-803 and MKN-45 cells, deguelin suppressed the proliferation and arrested cell cycle by p21-mediated inhibition of cyclin E. We further present in vitro evidence that deguelin promoted apoptosis of cancer cells by decreasing the phospho-Akt signaling and affecting expression of the apoptosis-associated genes Bax and Bcl-2. Additionally, deguelin was found to suppress the migration and invasion of gastric cancer cells. Taken together, these results indicated that deguelin exerted anticancer activity of human gastric cancer MGC-803 and MKN-45 cells in vitro.

#2714, a novel active inhibitor with potent G2/M phase arrest and antitumor efficacy in preclinical models

Arresting cell cycle has been one of the most common approaches worldwide in cancer therapy. Specifically, arresting cells in the G2/M phase is a promising therapeutic approach in the battle against lung cancer. In the present study, we demonstrated the anticancer activities and possible mechanism of compound #2714, which can prompt G2/M phase arrest followed by cell apoptosis induction in Lewis lung carcinoma LL/2 cells. In vitro, #2714 significantly inhibited LL/2 cell viability in a concentration- and time-dependent manner while exhibiting few toxicities on non-cancer cells. The mechanism study showed that cell proliferation inhibition due to the treatment with #2714 correlated with G2/M phase arrest and was followed by LL/2 cell apoptosis. The characterized changes were associated with the downregulation of phosphorylated cell division cycle 25C (Cdc25C) and upregulation of p53. Apoptosis-associated activation of cleaved caspase-3 was also detected. Moreover, #2714 strongly attenuated LL/2 cell proliferation by disrupting the phosphorylation of p44/42 mitogen-activated protein kinase (MAPK). In vivo, intraperitoneal administration of #2714 (25–100 mg/kg/day) to mice bearing established tumors in xenograft models significantly prevented LL/2 tumor growth (58.1%) without detectable toxicity. Compound #2714 significantly increased apoptosis in LL/2 lung cancer cells in mice models, as observed via terminal deoxynucleotidyl transferase (TdT) dUTP nick-end labeling (TUNEL) assay, and the data from an immunohistochemical analysis showed that #2714 remarkably inhibited the proliferation and angiogenesis of lung cancer in vivo. Taken together, our data suggest that #2714 has a high potential anti-lung cancer efficacy with a pathway-specific mechanism of G2/M phase arrest and subsequent apoptosis induction both in vitro and in vivo; its potential to be an anticancer candidate warrants further investigation.

Deguelin suppresses angiogenesis in human hepatocellular carcinoma by targeting HGF-c-Met pathway

Angiogenesis plays a crucial role in the development of human hepatocellular carcinoma (HCC). In the present study, we found a natural compound, deguelin, has a profound anti-angiogenesis effect on HCC. Deguelin suppressed vascular endothelial growth factor (VEGF)-induced human umbilical vascular endothelial cells (HUVECs) proliferation, migration, invasion, and capillary-like tube formation in vitro and reduced tumor angiogenesis in vivo. We discovered that VEGF receptor-mediated signal transduction cascades in HUVECs were inhibited by deguelin. Deguelin decreased the autocrine of VEGF in HCC cells in a time- and dose-dependent manner. Additionally, deguelin suppressed HGF-induced activation of the c-Met signaling pathway. Knocking down c-Met or inhibition of c-Met activation impaired HGF-mediated VEGF production. Importantly, we produced patient-derived hepatocellular carcinoma xenografts to evaluate the therapeutic effect of deguelin in vivo. Taken together, these results indicate that deguelin could inhibit HCC through suppression of angiogenesis on vascular endothelial cells and reduction of proangiogenic factors in cancer cells.

Synaptonemal complex protein 3 is associated with lymphangiogenesis in non-small cell lung cancer patients with lymph node metastasis

Background

The interaction of vascular endothelial growth factor-C (VEGF-C)/VEGF-D/VEGF receptor-3 is considered to be a major driver of lymphangiogenesis, however the mechanism of this process remains unclear. We aimed to investigate the possible lymphangiogenic significance of synaptonemal complex protein 3 (SCP3) in non-small cell lung cancer (NSCLC).

Methods

The expression of SCP3, VEGF-C, and VEGF-D were measured and examined a correlation between SCP3 and VEGF-C or VEGF-D in various human lung cancer cell lines. Subsequently, we assessed SCP3, VEGF-A, VEGF-B, VEGF-C, and VEGF-D expression in archival tumor tissues from 89 NSCLC patients with lymph node (LN) metastasis by combined immunohistochemistry with quantitative digital image analysis.

Results

Positive correlations between SCP3 and VEGF-C expression (R² = 0.743) and VEGF-D expression (R² = 0.932) were detected in various human lung cancer cell lines. The high expression of SCP3, VEGF-A, VEGF-B, VEGF-C, and VEGF-D were detected in 24 (27.0%), 22 (24.7%), 27 (30.3%), 27 (30.3%), and 24 cases (27.0%), respectively. Notably, SCP3 positively correlated with VEGF-C and VEGF-D expression (for both, P < 0.001) and negatively correlated with VEGF-A and VEGF-B expression (P = 0.029 and P = 0.026, respectively). In multivariate analysis of patients with LN metastasis, SCP3 expression predicted worse overall survival (hazard ratio = 1.86, P = 0.008).

Conclusions

SCP3 is associated with lymphangiogenesis and provides insight into the SCP3-VEGF-C/VEGF-D axis based cancer therapy strategy.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-017-1241-5) contains supplementary material, which is available to authorized users.

Deguelin Attenuates Allergic Airway Inflammation via Inhibition of NF-κb Pathway in Mice

Asthma is a chronic respiratory disease characterized by airway inflammation and remodeling, resulting in a substantial economic burden on both patients and society. Deguelin, a constituent of the Leguminosae family, exhibits anti-proliferative and anti-inflammatory activities in cancer mice models via inhibiting phosphatidylinositol 3-kinases and the NF-κB pathway. We demonstrated that deguelin effectively reduced OVA-induced inflammatory cell recruitment, decreased lung tissue inflammation and mucus production, suppressed airway hyperresponsiveness, and inhibited serum immunoglobulin and Th2 cytokine levels in a dose-dependent manner in asthmatic mice. In addition, we found that deguelin reduced inflammatory gene expressions both in vivo and in vitro, which were closely associated with activation of the NF-κB signaling pathway. Thus, we further explored the underlying mechanisms of deguelin in normal human bronchial epithelial cells (BEAS-2B). Our results suggested that deguelin inhibited NF-κB binding activity by enhancing the ability of IκBα to maintain NF-κB in an inactive form in the cytoplasm and preventing the TNF-α induced translocation of p65 to the nucleus. In conclusion, our research indicates that deguelin attenuates allergic airway inflammation via inhibition of NF-κB pathway in mice model and may act as a potential therapeutic agent for patients with allergic airway inflammation.

Deguelin inhibits proliferation and migration of human pancreatic cancer cells in vitro targeting hedgehog pathway

Pancreatic cancer (PC) is a highly lethal malignancy with few effective therapies. Deguelin, a natural compound of the flavonoid family of products, has been reported to have an inhibitory effect on various cancers. In the present study, we investigated whether deguelin had antitumor efficacy in PC. Deguelin treatment was observed to inhibit growth and induce apoptosis in two PC cell lines (Bxpc-3 and Panc-1). In addition, it inhibited migration and invasion in these two cell lines. The activation of the hedgehog (Hh) signaling pathway, as well as matrix metalloproteinases (MMP)-2 and MMP-9, was suppressed by deguelin. These results suggest that deguelin may be a potential chemotherapeutic agent for PC, possibly through the suppression of the Hh signaling pathway.

Modulation of signal transduction pathways by natural compounds in cancer

Cancer is generally regarded as the result of abnormal growth of cells. According to World Health Organization, cancer is the leading cause of mortality worldwide. Mother nature provides a large source of bioactive compounds with excellent therapeutic efficacy. Numerous phytochemicals from nature have been investigated for anticancer properties. In this review article, we discuss several natural compounds, which have shown anti-cancer activity. Natural compounds induce cell cycle arrest, activate intrinsic and extrinsic apoptosis pathways, generate Reactive Oxygen Species (ROS), and down-regulate activated signaling pathways, resulting in inhibition of cell proliferation, progression and metastasis of cancer. Several preclinical studies have suggested that natural compounds can also increase the sensitivity of resistant cancers to available chemotherapy agents. Furthermore, combining FDA approved anti-cancer drugs with natural compounds results in improved efficacy. On the basis of these exciting outcomes of natural compounds against several cancer types, several agents have already advanced to clinical trials. In conclusion, preclinical results and clinical outcomes against cancer suggest promising anticancer efficacy of agents from natural sources.

Novel application assigned to toluquinol: inhibition of lymphangiogenesis by interfering with VEGF-C/VEGFR-3 signalling pathway

BACKGROUND AND PURPOSE

Lymphangiogenesis is an important biological process associated with the pathogenesis of several diseases, including metastatic dissemination, graft rejection, lymphoedema and other inflammatory disorders. The development of new drugs that block lymphangiogenesis has become a promising therapeutic strategy. In this study, we investigated the ability of toluquinol, a 2-methyl-hydroquinone isolated from the culture broth of the marine fungus Penicillium sp. HL-85-ALS5-R004, to inhibit lymphangiogenesis in vitro, ex vivo and in vivo.

EXPERIMENTAL APPROACH

We used human lymphatic endothelial cells (LECs) to analyse the effect of toluquinol in 2D and 3D in vitro cultures and in the ex vivo mouse lymphatic ring assay. For in vivo approaches, the transgenic Fli1:eGFPy1 zebrafish, mouse ear sponges and cornea models were used. Western blotting and apoptosis analyses were carried out to search for drug targets.

KEY RESULTS

Toluquinol inhibited LEC proliferation, migration, tubulogenesis and sprouting of new lymphatic vessels. Furthermore, toluquinol induced apoptosis of LECs after 14 h of treatment in vitro, blocked the development of the thoracic duct in zebrafish and reduced the VEGF-C-induced lymphatic vessel formation and corneal neovascularization in mice. Mechanistically, we demonstrated that this drug attenuates VEGF-C-induced VEGFR-3 phosphorylation in a dose-dependent manner and suppresses the phosphorylation of Akt and ERK1/2.

CONCLUSIONS AND IMPLICATIONS

Based on these findings, we propose toluquinol as a new candidate with pharmacological potential for the treatment of lymphangiogenesis-related pathologies. Notably, its ability to suppress corneal neovascularization paves the way for applications in vascular ocular pathologies.

Deguelin-induced blockade of PI3K/protein kinase B/MAP kinase signaling in zebrafish and breast cancer cell lines is mediated by down-regulation of fibroblast growth factor receptor 4 activity

Deguelin, a natural component derived from leguminous plants, has been used as pesticide in some regions. Accumulating evidence show that deguelin has promising chemopreventive and therapeutic activities against cancer cells. This study shows that low concentrations of deguelin can lead to significant delay in zebrafish embryonic development through growth inhibition and induction of apoptosis. Furthermore, we identified fibroblast growth factor receptor 4 (FGFR4) as the putative target of deguelin. The candidate was initially identified by a microarray approach and then validated through in vitro experiments using hormone‐responsive (MCF‐7) and nonresponsive (MDA‐MB‐231) human breast cancer cell lines. The results show that deguelin suppressed cell proliferation and induced apoptosis in both cancer cell lines, but not in Hs 578Bst cells, by blocking PI3K/AKT and mitogen‐activated protein kinases (MAPK) signaling. The FGFR4 mRNA and protein level also diminished in a dose‐dependent manner. Interestingly, we found that forced FGFR4 overexpression attenuated deguelin‐induced proliferative suppression and apoptotic cell death in both zebrafish and MCF‐7 cell lines, p‐AKT and p‐ERK levels were restored upon FGFR4 overexpression. Taken together, our results strongly suggest that deguelin inhibition of PI3K/AKT and MAPK signaling in zebrafish and breast cancer cell lines is partially mediated through down‐regulation of FGFR4 activity.

A potential small-molecule synthetic antilymphangiogenic agent norcantharidin inhibits tumor growth and lymphangiogenesis of human colonic adenocarcinomas through blocking VEGF-A,-C,-D/VEGFR-2,-3 "multi-points priming" mechanisms in vitro and in vivo

Background

Tumor lymphangiogenesis plays an important role in promoting growth and metastasis of tumors, but no antilymphangiogenic agent is used clinically. Based on the effect of norcantharidin (NCTD) on lymphangiogenesis of human lymphatic endothelial cells (LECs), we firstly investigated the antilymphangiogenic activity of NCTD as a tumor lymphangiogenic inhibitor for human colonic adenocarcinomas (HCACs).

Methods

In vivo and in vitro experiments to determine the effects of NCTD on tumor growth and lymphangiogenesis of the in-situ colonic xenografts in nude mice, and lymphatic tube formation of the three-dimensional (3-D) of the co-culture system of HCAC HT-29 cells and LECs were done. Proliferation, apoptosis, migration, invasion, Ki-67, Bcl-2 and cell cycle of LECs and the co-culture system in vitro were respectively determined. Streparidin-peroxidase staining, SABC, western blotting and RT-PCR were respectively used to examine the expression of LYVE-1, D2-40, CK20 (including their LMVD), and VEGF-A, VEGF-C, VEGF-D, VEGFR-2 and VEGFR-3 in vitro and in vivo.

Results

NCTD inhibited tumor growth and lymphangiogenesis of the in-situ colonic xenografts in vivo, and these observations were confirmed by facts that lymphatic tube formation, proliferation, apoptosis, migration, invasion, S-phase cell cycle, and Ki-67 and Bcl-2 expression in vitro, and LYVE-1, D2-40, CK20 expression and their LMVD in vitro and in vivo were inhibited and affected. Furthermore, the expression of VEGF-A, VEGF-C, VEGF-D, VEGFR-2 and VEGFR-3 at protein/mRNA levels in the process of lymphatic tube formation in vitro and tumor lymphangiogenesis in vivo was downregulated; NCTD in combination with mF4-31C1 or Sorafenib enhanced these effects.

Conclusions

NCTD inhibits tumor growth and lymphangiogenesis of HCACs through “multi-points priming” mechanisms i.e. affecting related malignant phenotypes, inhibiting Ki-67 and Bcl-2 expression, inducing S-phase cell cycle arrest, and directly or indirectly downregulating VEGF-A,-C,-D/VEGFR-2,-3 signaling pathways. The present finding strongly suggests that NCTD could serve as a potential antilymphangiogenic agent for tumor lymphangiogenesis and is of importance to explore NCTD is used for antitumor metastatic comprehensive therapy for HCACs.

A small molecular agent YL529 inhibits VEGF-D-induced lymphangiogenesis and metastasis in preclinical tumor models in addition to its known antitumor activities

Background

The lymph node metastasis is a key early step of the tumor metastatic process. VEGFD-mediated tumor lymphangiogenesis plays a key role, since down-regulation of p-VEGFR-3 could block the lymph node metastasis. YL529 has been reported to possess potent anti-angiogenesis and antitumor activities; however, its roles in tumor-associated lymphangiogenesis and lymphatic metastasis remain unclear.

Method

We investigated the effect of YL529 on tumor-associated lymphangiogenesis and lymph node metastasis using in vitro lymph node metastasis models and in vivo subcutaneous tumor models in C57 BL/6 mice.

Result

We found that YL529 inhibited VEGF-D-induced survival, proliferation and tube-formation of Human Lymphatic Endothelial Cells. Furthermore, in established in vitro and in vivo lymph node metastasis models using VEGF-D-LL/2 cells, YL529 significantly inhibited the tumor-associated lymphangiogenesis and metastasis. At molecular level, YL529 down-regulated p-VEGFR-3, p-JNK and Bax while up-regulated Bcl-2.

Conclusion

YL529 provided the therapeutic benefits by both direct effects on tumor cells and inhibiting lymphangiogenesis and metastasis via the VEGFR-3 signaling pathway, which may have significant direct clinical implications.

Suppressive function of low-dose deguelin on the invasion of oral cancer cells by downregulating tumor necrosis factor alpha-induced nuclear factor-kappa B signaling

BACKGROUND

Deguelin has both antiproliferation and antimetastasis activities. However, high-dose deguelin elicits many undesired side effects. The purpose of this study was to investigate whether the low-dose deguelin can prevent the metastasis of oral cancer.

METHODS

The dose effects of deguelin on metastasis of oral cancer cells were analyzed by in vitro invasion assay and an orthotropic xenograft mouse model. The involvement of tumor necrosis factor alpha (TNF-α)-induced nuclear factor-kappa B (NF-κB) signaling was examined by Western blot and reporter assay.

RESULTS

Low-dose deguelin, which has minimal cytotoxicity, significantly inhibited the invasion and migration of oral cancer cells. These inhibitory effects of low-dose deguelin were mediated by suppressing TNF-α-induced activation of IκB kinase leading to the inhibition of IκB phosphorylation, NF-κB transcriptional activity, and matrix metalloproteinase-2 (MMP2) expression. The low-dose deguelin treatment significantly inhibited tumor growth and invasion without systemic toxicity.

CONCLUSION

The low-dose deguelin suppressed the invasion and migration of oral cancer by downregulating TNF-α-induced NF-κB signaling. © 2015 Wiley Periodicals, Inc. Head Neck 38: E524-E534, 2016.

In vitro and in vivo anti-angiogenic activity of girinimbine isolated from Murraya koenigii

Girinimbine is a carbazole alkaloid isolated from the stem bark and root of Murraya koenigii. Here we report that girinimbine is an inhibitor of angiogenic activity both in vitro and in vivo. MTT results showed that girinimbine inhibited proliferation of human umbilical vein endothelial cells, while results from endothelial cell invasion, migration, tube formation, and wound healing assays demonstrated significant time- and dose-dependent inhibition by girinimbine. A proteome profiler array done on girinimbine-treated human umbilical vein endothelial cells showed that girinimbine had mediated regulation of pro-angiogenic and anti-angiogenic proteins. The anti-angiogenic potential of girinimbine was also evidenced in vivo in the zebrafish embryo model wherein girinimbine inhibited neo vessel formation in zebrafish embryos following 24 hours of exposure. Together, these results showed that girinimbine could effectively suppress angiogenesis, suggestive of its therapeutic potential as a novel angiogenesis inhibitor.

Millettia pachycarpa exhibits anti-inflammatory activity through the suppression of LPS-induced NO/iNOS expression

The present study was designed to investigate the in vitro and in vivo anti-inflammatory activity of flavonoids isolated from Millettia pachycarpa Benth. The seeds of M. pachycarpa Benth were extracted with ethanol and subjected to chromatographic separation for the isolation of bioactive compounds. Their structures were elucidated by spectroscopic methods. The anti-inflammatory activity of the compounds was investigated by evaluating the inhibition ability of NO production, iNOS activity and iNOS protein expression induced by LPS-stimulated RAW264.7 macrophages in vitro and the carrageenan-induced hind paw edema model in vivo. Molecular docking simulation was also employed to obtain the binding parameters in the binding pocket of iNOS. Thirteen compounds (1-13) were isolated from Chinese herbal medicine M. pachycarpa Benth. Among them, 4-hydroxylonchocarpin (6) and deguelin (7) exhibited remarkable inhibitory rates of 66.5% and 57.7%, respectively, compared with that of 52.5% of indomethacin in LPS-induced macrophages cells. 4-hydroxylonchocarpin (6) with low toxicity (IC50 > 100 μm) exhibited better inhibitory effects to positive control of 1400W on iNOS activity at the concentration of 10 μm. Western blot assay revealed that 4-hydroxylonchocarpin (6) inhibited iNOS protein expression in RAW264.7 cells and molecular docking simulation showed that 4-hydroxylonchocarpin (6) fit well into the binding pocket of iNOS. In the carrageenan-induced paw edema model, our data revealed that the anti-inflammatory potential of 4-hydroxylonchocarpin (6) at 10 mg/kg showed comparable inhibitory ability to indomethacin at 5 h while a higher concentration of 4-hydroxylonchocarpin (6) at 50 mg/kg showed higher inhibitory activity than indomethacin, which was further confirmed by plasma levels of nitrite. The overall results suggest that 4-hydroxylonchocarpin (6) might be used as a potential therapeutic agent for inflammation-associated disorders.

Separation of flavonoids from Millettia griffithii with high-performance counter-current chromatography guided by anti-inflammatory activity

Millettia griffithii is a unique Chinese plant located in the southern part of Yunnan Province. Up to now, there is no report about its phytochemical or related bioactivity research. In our previous study, the n-hexane crude extract of Millettia griffithii revealed significant anti-inflammatory activity at 100 μg/mL, inspiring us to explore the anti-inflammatory constituents. Four fractions (I, II, III, and A) were fractionated from n-hexane crude extract by high-performance counter-current chromatography with solvent system composed of n-hexane/ethyl acetate/methanol/water (8:9:8:9, v/v) and then were investigated for the potent anti-inflammatory activity. Fraction A, with the most potent inhibitory activity was further separated to give another four fractions (IV, V, VI, and B) with solvent system composed of n-hexane/ethyl acetate/methanol/water (8:4:8:4, v/v). Compound V and fraction B exhibited remarkable anti-inflammatory activity with nitric oxide inhibitory rate of 80 and 65%, which was worth further fractionation. Then, three fractions (VII, VIII, and IX) were separated from fraction B with a solvent system composed of n-hexane/ethyl acetate/methanol/water (8:1:8:1, v/v), with compound VIII demonstrating the most potent inhibitory activity (80%). Finally, the IC50 values of compound V and VIII were tested as 38.2 and 14.9 μM. The structures were identified by electrospray ionization mass spectrometry and(1)H and (13)C NMR spectroscopy.

In vitro and in vivo antiangiogenic activity of caged polyprenylated xanthones isolated from Garcinia hanburyi Hook. f

Eleven known caged polyprenylated xanthones 1–11 were isolated from the resin of Garcinia hanburyi Hook. f., and their structures were identified by their MS, NMR and UV spectra. These xanthones showed significant cytotoxicities against four human cancer cell lines (HeLa, A549, HCT-116, and HepG-2) and strong inhibition against the proliferation of the HUVEC cell line in vitro by the MTT method. Furthermore, in an in vivo zebrafish model, xanthones 3 (morellic acid), 7 (gambogenin) and 9 (isogambogenic acid) showed comparable antiangiogenic activities with less toxicities than xanthone 1 (gambogic acid), as evaluated by death and heart rates of treated zebrafish. Xanthone 7 exhibited antiangiogenic activity with no toxicity at concentrations ranging from 8 µM to 16 µM. Meanwhile, xanthones 1, 3, 7 and 9 strongly inhibited the migration of HUVEC at a low concentration of 0.5 µM in HUVEC cell migration assay in vitro. Taken together, these findings strongly suggest that xanthone 7 might be a novel angiogenesis inhibitor.

Efficacy and mechanism of action of Deguelin in suppressing metastasis of 4T1 cells

Cancer related deaths in breast cancer patients are due to metastasis of the disease. Murine 4T1 cells (Murine mammary cancer cell line developed from 6-thioguanine resistant tumor) provide an excellent research tool for metastasis related studies because these cells are highly aggressive and readily metastasize to the lungs. In this study we determined the effect of Deguelin on in vivo/vitro growth and metastasis of 4T1 cells. Deguelin inhibited the in vitro growth of 4T1 cells in a time and dose dependent manner accompanied with reduced nuclear PCNA immunostaining. In cells treated with Deguelin, reduced expression of nuclear c-Met, and its downstream targets such p-ERK and p-AKT was observed. Deguelin reduced the cell migration in 4T1 cells as determined by scratch wound assay. Combined treatment with Deguelin + ERK or PI3K/AKT inhibitor had no additional effect on cell migration. These results indicated that the action of Deguelin on cell migration may be mediated by AKT and ERK mediated signaling pathways. In vivo, Deguelin treatment significantly inhibited growth of 4T1 cells. Deguelin also reduced the occurrence of metastatic lung lesions by 33 % when cells were injected intravenously into Balb/c female mice. There was no difference in the body weight, nor was there a difference in liver and spleen weights between vehicle treated-control and Deguelin-treated animals, which indicated that Deguelin was nontoxic at the dose used in the present study. These results provide rationale for developing Deguelin as a chemotherapeutic agent for triple negative breast cancer patients.

A Concise Enantioselective Synthesis and Cytotoxic Evaluation of the Anticancer Rotenoid Deguelin Enabled by a Tandem Knoevenagel/Conjugate Addition/Decarboxylation Sequence

(-)-Deguelin is a rotenoid natural product that possesses significant potential as a chemopreventive and chemotherapeutic agent. While several racemic syntheses of deguelin have been reported, a formal evaluation of the anticancer activity of both the natural and unnatural enantiomers remains lacking. We describe herein the successful application of a flexible and selective thiourea-catalyzed cyclization strategy toward the enantioselective total synthesis of deguelin, which allows access to either stereoisomer for biological studies. The synthesis was completed in six steps (longest linear) with no protecting groups. The evaluation of both enantiomers of the natural product demonstrated potent inhibition of several cancer cell lines by these compounds, but interestingly showed that the unnatural (+)-deguelin preferentially inhibited the growth of MCF-7 breast cancer and HepG2 liver carcinoma cells when compared to the natural product.

Suppression of lymphangiogenesis in human lymphatic endothelial cells by simultaneously blocking VEGF-C and VEGF-D/VEGFR-3 with norcantharidin

Lymph node metastasis of tumors is a crucial early step in the metastatic process. Tumor lymphangiogenesis plays an important role in promoting tumor metastasis to regional lymph nodes. Norcantharidin (NCTD) has been reported to possess potent anti-angiogenesis and antitumor properties in several cell lines and xenograft tumor models. However, its role in tumor-associated lymphangiogenesis and lymphatic metastasis remains unclear. Here, we investigated the effect of NCTD on proliferation, apoptosis, migration, invasion and the lymphatic tube formation, lymphangiogenesis, of human lymphatic endothelial cells (HLECs) in vitro by MTT, proliferation assay, Hoechst staining and flow cytometry, scraping line method, Matrigel invasion assay, inverted or fluorescence microscope and transmission electron microscope. Moreover, the underlying mechanisms, such as VEGF-C, VEGF-D, VEGFR-3 at protein and mRNA levels in lymphangiogenesis using 3-dimensional (3-D) culture of HLECs were measured by immunohistochemistry, western blotting and real-time polymerase chain reaction (RT-PCR). It was shown that NCTD inhibited proliferation, migration, invasion and lymphatic tube formation (forming-lymphatic and/or formed-lymphatic) of HLECs, induced HLEC apoptosis (all P<0.01) significantly, in a dose- and time-dependent manner (IC50 6.8 µg/ml); and downregulated the expression of VEGF-C, VEGF-D and VEGFR-3 at protein or/and mRNA levels (P<0.01) in HLEC lymphatic tube formation. Thus, we identified for the first time that NCTD inhibited HLEC lymphangiogenesis by simultaneously blocking VEGF-C and VEGF-D/VEGFR-3 in vitro. The present findings may be of importance to explore the therapeutical target or strategy of NCTD for tumor lymphangiogenesis and lymphatic metastasis.

Role of Akt-mediated VEGF signaling pathway in lymphangiogenesis in gastric cancer

Tumor lymphangiogenesis plays a vital role in lymphatic metastasis of solid tumors and is an important index for evaluation of prognosis. However, due to the lack of understanding of lymphatic endothelium-specific factors and the limitation of detection techniques, the specific mechanisms of lymphatic metastasis and molecule pathways involved in tumor lymphangiogenesis are not well understood. Akt signal pathway is an important transduction pathway that is closely related with the occurrence, proliferation, anti-apoptosis and metastasis of tumors. It has been found that Akt signaling has a close relationship with VEGF signal pathway and mediates lymphatic metastasis or tumor lymphangiogenesis. This article will summarize the role of Akt-mediated VEGF signaling pathway in lymphangiogenesis in gastric cancer.

LyP-1-conjugated doxorubicin-loaded liposomes suppress lymphatic metastasis by inhibiting lymph node metastases and destroying tumor lymphatics

Lymphatic metastasis can be greatly promoted by metastases growth and lymphangiogenesis in lymph nodes (LNs). LyP-1, a cyclic peptide, is able to specifically bind with tumor cells and tumor lymphatics in metastatic LNs. This work aimed to use LyP-1-conjugated liposomes (L-LS) loaded with doxorubicin (DOX) (L-LS/DOX) to suppress lymphatic metastasis by inhibiting both metastases and tumor lymphatics in LNs. L-LS were prepared and exhibited sizes around 90 nm and spherical morphology as characterized by transmission electron microscopy. The in vitro cellular studies showed that LyP-1 modification obviously increased liposome uptake by MDA-MB-435 tumor cells and enhanced the cytotoxicity of liposomal DOX. A popliteal and iliac LN metastases model was successfully established by subcutaneous inoculation of tumor cells to nude mice. The immunofluorescence staining analysis indicated that LyP-1 modification enabled specific binding of liposome with tumor lymphatics and enhanced the destroying effect of liposomal DOX on tumor lymphatics. The in vivo fluorescence imaging and pharmacodynamic studies showed that LyP-1 modification increased liposome uptake by metastatic LNs and that L-LS/DOX significantly decreased metastatic LN growth and LN metastasis rate. These results suggested that L-LS/DOX were an effective delivery system for suppressing lymphatic metastasis by simultaneously inhibiting LN metastases and tumor lymphatics.