Dauricine inhibits insulin-like growth factor-Ⅰ-induced hypoxia inducible factor la protein accumulation and vascular endothelial growth factor expression in human breast cancer cells

Aim： To investigate the effects of dauricine （Dau） on insulin-like growth factor-Ⅰ （IGF-Ⅰ）-induced hypoxia inducible factor 1α （HIF-1α） and vascular endothelial growth factor （VEGF） expression in human breast cancer cells （MCF-7）. Methods： Serum-starved MCF-7 cells were pretreated for 1 h with different concentrations of Dau, followed by incubation with IGF-Ⅰ for 6 h. HIF-1α and VEGF protein expression levels were analyzed by Western blotting and ELISA, respectively. HIF-1α and VEGF mRNA levels were determined by real-time PCR. In vitro angiogenesis was observed via the human umbilical vein endothelial cell （HUVEC） tube formation assay. An in vitro invasion assay on HUVECs was performed. Results： Dau significantly inhibited IGF-Ⅰ-induced HIF-1α protein expression but had no effect on HIF-1α mRNA expression. However, Dau remarkably suppressed VEGF expression at both protein and mRNA levels in response to IGF-Ⅰ. Mechanistically, Dau suppressed IGF-Ⅰ-induced HIF-1α and VEGF protein expression mainly by blocking the activation of PI-3K/AKT/mTOR signaling pathway. In addition, Dau reduced IGF-Ⅰ-induced HIF-1α protein accumulation by inhibiting its synthesis as well as by promoting its degradation. Functionally, Dau inhibited angiogenesis in vitro. Moreover, Dau had a direct effect on IGF-Ⅰ-induced invasion of HUVECs. Conclusion： Dau inhibits human breast cancer angiogenesis expression, which may provide a novel potential mechanism for by suppressing HIF-1α protein accumulation and VEGF the anticancer activities of Dau in human breast cancer.     

Bp5250 inhibits vascular endothelial growth factor-induced angiogenesis and HIF-1α expression on endothelial cells

Angiogenesis plays a critical role in many physiological and pathological phenomena. A number of anti-angiogenesis drugs have been used in the clinical treatment of diseases such as malignant tumors and macular degeneration. Vascular endothelial growth factor (VEGF), the major pro-angiogenesis factor, is known to stimulate various steps of endothelial angiogenic activity, such as proliferation, migration, and differentiation into vessel-like tubes. In this study, we tested the effects of bp5250 on the angiogenesis of human umbilical endothelial cells (HUVECs). Bp5250 suppressed VEGF-induced endothelial cell proliferation by triggering apoptosis, and reduced endothelial cell migration toward VEGF. Bp5250 also decreased VEGF-stimulated tube formation and rat aortic ring sprouting on Matrigel in a concentration-dependent manner. In the VEGF-activated signaling pathways, bp5250 decreased the phosphorylation of ERK, p38, PI3K-AKT, Src, and FAK and also reduced the activation of the cytoskeleton-associated Rho family, all in a concentration-dependent manner. Bp5250 also attenuated the hypoxia-inducible factor-1α (HIF-1α) and VEGF-stimulated mRNA expression of HUVECs under the hypoxic condition. In vivo, angiogenesis was restrained by a daily intraperitoneal administration of bp5250 in a dose-dependent manner (1–3 mg/kg/d) in the Matrigel plug implantation assay. These results indicate that bp5250 is a potential candidate for developing anti-angiogenic agents.     

Molecular biomarkers of cantharidin-induced cardiotoxicity in Sprague-Dawley rats: Troponin T,vascular endothelial growth factor and hypoxia inducible factor-1α

Early diagnosis of cantharidin-induced myocardial injury is the key to reduce the fatality rate in clinical practice. The purpose of the present study was to explore biomarkers that can be used for the prediction and diagnosis of cantharidin-induced myocardial injury. Of 65 male Sprague-Dawley rats weighing 200-230 g, 25 rats were divided into five groups according to the administration dose of cantharidin (0, 1.34, 2.67, 4 and 5.34 mg/kg; n = 5 per group) and the other 40 rats were treated with 2.67 mg/kg cantharidin and divided into nine groups according to the administration time (0, 1, 2, 4, 6, 8, 12, 24, 48 and 72 hours; n = 4 per group). Pathological changes of hypoxia, necrosis and inflammation were confirmed in heart samples that were exposed to cantharidin by hematoxylin-eosin staining and overall scores of pathological changes among heart samples in cantharidin exposure groups showed an increasing trend compared with in the control group. Coexpression of vascular endothelial growth factor (VEGF), hypoxia inducible factor-1α (HIF-1α) and caspase9 was shown in the myocardium by immunofluorescence staining. Western blotting results showed that expression of VEGF, HIF-1α and caspase9 in cantharidin-treated rat hearts showed an increasing trend compared with in the control group. Results of enzyme-linked immunosorbent assay suggested that plasma levels of troponin T (TN-T), VEGF and HIF-1α were elevated at different intervals after cantharidin administration, and VEGF and HIF-1α had a significant linear relationship with TN-T that was verified by multiple linear regression analysis. Preliminary results serve to illustrate that TN-T, VEGF and HIF-1α might be valuable molecular markers in cantharidin-induced myocardial injury and that diagnostic accuracy needs to be studied further.     

TNF-α induces CXCL1 chemokine expression and release in human vascular endothelial cells in vitro via two distinct signaling pathways

Aim： Chemokines usually direct the movement of circulating leukocytes to sites of inflammation or injury. CXCL1/GRO-a has been shown to be upregulated in atherosclerotic lesions and various cancers. The aim of this study was to investigate the mechanisms underlying the TNF-α-induced release of CXCL1 from human vascular endothelial cells in vitro. Methods： Human umbilical vein endothelial cells （HUVECs） were treated with different proinflam-matory mediators and growth factors. CXCL1 expression and secretion were determined using RT-PCR and ELISA, respectively. TNF-a-induced cell signaling was assayed with Western blotting. Cell viability/growth was determined using MTTassay. Monocyte migration was measured with transwell migration assay. Results： Among the 17 mediators and growth factors tested, TNF-α, LPS and thrombin induced marked increase in CXCL1 release from HUVEC cells. TNF-α （2, 5 ng/mL） induced CXCL1 release and mRNA expression in the cells in concentration- and time-dependent manners. TNF-α （5 ng/mL） caused activation of JNK, p38 MAPK, PI3K and Akt, whereas pretreatment with JNK inhibitor （SP600125）, p38 MAPK inhibitor （SB202190） or PI-3K inhibitor （LY294002） significantly suppressed TNF-a-induced CXCL1 release from the cells. But only SP600125 significantly reduced TNF-a-induced CXCL1 mRNA expression in the cells. Moreover, dexamethasone （up to 500 nmol/L） failed to affect TNF-a-induced CXCL1 release from the cells. In functional studies, recombinant CXCL1 enhanced HUVEC proliferation, and both recombinant CXCL1 and TNF-a-induced CXCL1 from HUVECs attracted human monocyte migration. Conclusion： TNF-a stimulates CXCL1 release from human ECs through JNK-mediated CXCL1 mRNA expression and p38 MAPK- and PI-3K-mediated CXCL1 secretory processes.     

Prostaglandin E₂ regulates cellular migration via induction of vascular endothelial growth factor receptor-1 in HCA-7 human colon cancer cells

An important event in the development of tumors is angiogenesis, or the formation of new blood vessels. Angiogenesis is also known to be involved in tumor cell metastasis and is dependent upon the activity of the vascular endothelial growth factor (VEGF) signaling pathway. Studies of mice in which the EP3 prostanoid receptors have been genetically deleted have shown a role for these receptors in cancer growth and angiogenesis. In the present study, human colon cancer HCA-7 cells were used as a model system to understand the potential role of EP3 receptors in tumor cell migration. We now show that stimulation of HCA-7 cells with PGE? enhanced the up-regulation of VEGF receptor-1 (VEGFR-1) expression by a mechanism involving EP3 receptor-mediated activation of phosphatidylinositol 3-kinase and the extracellular signal-regulated kinases. Moreover, the PGE? stimulated increase in VEGFR-1 expression was accompanied by an increase in the cellular migration of HCA-7 cells. Given the known involvement of VEGFR-1 in cellular migration, our results suggest that EP3 receptors may contribute to tumor cell metastasis by increasing cellular migration through the up-regulation of VEGFR-1 signaling.     

Interaction of vascular endothelial cells with leukocytes, platelets and cancer cells in inflammation, thrombosis and cancer growth and metastasis

Adhesion and migration of mammalian cells are of crucial importance in a number of biological events, such as fertilization, embryogenesis, pattern, tissue and organ formation, and in a variety of physiological and pathological processes, including lymphocyte trafficking, leukocyte recruitment, hemostasis, wound healing, tumor angiogenesis and cancer metastasis. All these     

Deguelin inhibits expression of IκBα protein in Raji and U937 cells

AIM: To determine whether deguelin can regulate the expression of nuclear factor kappa B (NF-kappaB) binding protein (IkappaBalpha) in U937 human leukemia cells and Raji human B lymphoma cells. METHODS: The localization of IkappaBalpha protein was investigated by using an immunofluorescence method. The expression of IkappaBalpha and NF-kappaB /p65 proteins in Raji and U937 cells were investigated by using Western blotting. Apoptosis was detected through annexin V/PI double-labeled cytometry. RESULTS: IkappaBalpha localized in the cytoplasm in untreated and deguelin-treated cells. After treatment with tumor necrosis factor alpha (TNF-alpha) or deguelin plus TNF-alpha for 15 min, there was a substantial reduction in the amount of IkappaBalpha protein. The expression of IkappaBalpha was downregulated by deguelin in Raji and U937 cells. Deguelin induced apoptosis in U937 cells. CONCLUSION: Deguelin inhibited the expression of IkappaBalpha protein in U937 and Raji cells. The anti-proliferative activity of deguelin is related to the signal pathway of NF-kappaB.     

Arsenic modulates heme oxygenase-1, interleukin-6, and vascular endothelial growth factor expression in endothelial cells: roles of ROS, NF-κB, and MAPK pathways

Chronic arsenic exposure has been linked to an increased risk of vascular diseases. To clarify the molecular mechanisms through which arsenic causes injuries to blood vessels, we analyzed the effects of arsenic trioxide on the cytotoxicity, intracellular reactive oxygen species (ROS), the expression of related genes, and signaling pathways involved in the SVEC4-10 mouse endothelial cells. Arsenic dose-dependently caused SVEC4-10 cell death, which is completely inhibited by α-lipoic acid (LA), a thioreductant, but partially ameliorated by Tiron, a potent superoxide scavenger. The mRNA levels of heme oxygenase-1 (HO-1), interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), and vascular endothelial growth factor (VEGF) were significantly increased by arsenic. The up-regulation of these can be blocked by LA instead of Tiron, suggesting ROS is not important in their increase. HO-1 competitive inhibitor zinc protoporphyrin improved the cytotoxicity of arsenic in an inverted-U dose-response curve, indicating the biphasic hormetic effect of HO-1. HO-1 siRNA decreased VEGF expression in response to arsenic. Arsenic exposure also enhanced NF-E2-related factor 2 (Nrf2) expression and increased activation of nuclear factor-κB (NF-κB). NF-κB inhibitor Bay 11-7082 reduced arsenic-mediated expression of HO-1 and IL-6. Selective blocking of the MAPK pathways with p38 inhibitor SB203580 significantly decreased arsenic-induced HO-1 and VEGF expression, while JNKs inhibitor SP600125 increased IL-6 expression. These results suggest that in arsenic-treated SVEC4-10 cells, HO-1 expression is mediated through Nrf2-, NF-κB-, and p38 MAPK-dependent signaling pathways and serves as an upstream regulator of VEGF. IL-6 expression is regulated by NF-κB and JNKs. In conclusion, oxidative stress may be associated with arsenic-induced cytotoxicity and endothelial gene up-regulation, but signaling transduction dominates the direct effects of ROS.     

Naringin inhibits growth potential of human triple-negative breast cancer cells by targeting β-catenin signaling pathway

Triple-negative (ER-/PR-/HER2-) breast cancer (TNBC) is a severe clinical problem because of its relatively poorer prognosis, aggressive behavior and lack of targeted therapies. Naringin, a major flavonoid extracted from citrus fruits, has been reported to exert promising anticancer activities. However, the detailed antitumor mechanism of naringin still remains enigmatic. In this study, TNBC cell lines-based in vitro and in vivo models were used to explore the anticancer effect and mechanism of naringin. Our data demonstrated that naringin inhibited cell proliferation, and promoted cell apoptosis and G1 cycle arrest, accompanied by increased p21 and decreased survivin. Meanwhile, β-catenin signaling pathway was found to be suppressed by naringin. In contrast, over-expressing β-catenin by adenoviral vector system in TNBC cells reversed the antitumor activity of naringin, and regulated p21 and survivin. Correspondingly, the antitumor potential of naringin was also observed in naringin-treated MDA-MB-231 xenograft mice, while immunohistochemical analysis of tumors from naringin-treated mice showed higher expression of p21 and lower expression of survivin and active β-catenin. Taken together, these results indicate that naringin could inhibit growth potential of TNBC cells by modulating β-catenin pathway, which suggests naringin might be used as a potential supplement for the prevention and treatment of breast cancer.     

PGC-1α ameliorates AngiotensinII-induced eNOS dysfunction in human aortic endothelial cells

Increasing evidences support that PGC-1α participates in regulating endothelial homeostasis, in part by mediating endothelial nitric oxide (NO) synthase (eNOS) activity and NO production. However, the molecular mechanisms by which PGC-1α regulates eNOS activity are not completely understood. In the present study, we investigated the effects of PGC-1α on eNOS dysfunction and further explore the underlying mechanisms. The results showed that PGC-1α expression was downregulated after AngiotensinII (AngII) treatment and paralleled with the decreased NO generation in human aortic endothelial cells. Overexpression of PGC-1α with adenovirus or pharmacological agonist ameliorated AngII-induced the decrease of NO generation, evidenced by the restoration of cGMP and nitrite concentration. Rather than affecting eNOS expression and uncoupling, PGC-1α inhibited AngII-induced decrease of eNOS serine 1177 phosphorylation through activation of PI3K/Akt signaling. In addition, PGC-1α overexpression suppressed AngII-induced the increase of PP2A-A/eNOS interaction and PP2A phosphatase activity, with a concomitant decrease in PP2A phosphorylation, leading to eNOS serine 1177 phosphorylation. However, pharmacological inhibition of PI3K/Akt signaling blunted the observed effect of PGC-1α on PP2A activity. Taken together, our findings suggest that PGC-1α overexpression improves AngII-induced eNOS dysfunction and that improved eNOS dysfunction is associated with activated PI3K/Akt pathway, impaired PP2A activity and reduced PP2A-A/eNOS association. These date indicate that forced PGC-1α expression may be a novel therapeutic approach for endothelial dysfunction.     

A positive circuit of VEGF increases Glut-1 expression by increasing HIF-1α gene expression in human retinal endothelial cells

Treatment of human retinal microvascular endothelial cells (HRMECs) with vascular endothelial growth factor 165 (VEGF₁₆₅) increased hypoxia-inducible factor 1α (HIF-1α), VEGF, and glucose transporter 1 (Glut-1) mRNA expression and Glut-1 protein localization to the membrane. In contrast, treatment of human retinal pigment epithelium cells with VEGF₁₆₅ did not induce HIF-1α, VEGF, and Glut-1 gene expression. Microvascular endothelial cells are surrounded by astrocytic end feet in the retina. Astrocyte-derived A-kinase anchor protein 12 overexpression during hypoxia downregulated VEGF secretion, and this conditioned medium reduced VEGF and Glut-1 expression in HRMECs, suggesting that communications between astrocytes and endothelial cells may be the determinants of the blood vessel network. In HRMECs, HIF-1α small interfering RNA transfection blocked the VEGF₁₆₅-mediated increase in VEGF and Glut-1 gene expression. Inhibition of protein kinase C (PKC) with inhibitor GF109203X or with a small interfering RNA targeting PKCζ attenuated the VEGF₁₆₅-induced Glut-1 protein expression and VEGF and Glut-1 mRNA expression. In addition, results of an immunoprecipitation assay imply an interaction between VEGF receptor 2 (VEGFR2) and PKCζ in HRMECs. Therefore, VEGF secretion by hypoxic astrocytes may upregulate HIF-1α gene expression, inducing VEGF and Glut-1 expression via the VEGFR2–PKCζ axis in HRMECs.     

Acanthoic acid inhibits LPS-induced inflammatory response by activating LXRα in human umbilical vein endothelial cells

Acanthoic acid, a pimaradiene diterpene isolated from Acanthopanax koreanum, has been reported to have anti-inflammatory activities. However, the effect of acanthoic acid on vascular inflammation has not been investigated. The aim of this study was to investigate the anti-inflammatory effects of acanthoic acid on lipopolysaccharide (LPS)-induced inflammatory response in human umbilical vein endothelial cells (HUVECs). The production of cytokines TNF-α and IL-8 was detected by ELISA. The expression of VCAM-1, ICAM-1, E-selectin, NF-κB and LXRα were detected by Western blotting. Adhesion of monocytes to HUVECs was detected by monocytic cell adhesion assay. The results showed that acanthoic acid dose-dependently inhibited LPS-induced TNF-α and IL-8 production. Acanthoic acid also inhibited TNF-α-induced IL-8 and IL-6 production. LPS-induced endothelial cell adhesion molecules, VCAM-1 and ICAM-1 were also inhibited by acanthoic acid. Acanthoic acid inhibited LPS-induced NF-κB activation. Furthermore, acanthoic acid dose-dependently up-regulated the expression of LXRα. In addition, our results showed that the anti-inflammatory effect of acanthoic acid was attenuated by transfection with LXRα siRNA. In conclusion, the anti-inflammatory effect of acanthoic acid is due to its ability to activate LXRα. Acanthoic acid may be a therapeutic agent for inflammatory cardiovascular disease.     

Astragalus polysaccharides suppress ICAM-1 and VCAM-1 expression in TNF-α-treated human vascular endothelial cells by blocking NF-κB activation

Aim:

To investigate the effects Astragalus polysaccharides (APS) on tumor necrosis factor (TNF)-α-induced inflammatory reactions in human umbilical vein endothelial cells (HUVECs) and to elucidate the underlying mechanisms.

Methods:

HUVECs were treated with TNF-α for 24 h. The amounts of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were determined with Western blotting. HUVEC viability and apoptosis were detected using cell viability assay and Hoechst staining, respectively. Reactive oxygen species (ROS) production was measured by DHE staining. Monocyte and HUVEC adhesion assay was used to detect endothelial cell adhesive function. NF-κB activation was detected with immunofluorescence.

Results:

TNF-α (1-80 ng/mL) caused dose- and time-dependent increases of ICAM-1 and VCAM-1 expression in HUVECs, accompanied by significant augmentation of IκB phosphorylation and NF-κB translocation into the nuclei. Pretreatment with APS (10 and 50 μg/mL) significantly attenuated TNFα-induced upregulation of ICAM-1 VCAM-1 and NF-κB translocation. Moreover, APS significantly reduced apoptosis, ROS generation and adhesion function damage in TNF-α-treated HUVECs.

Conclusion:

APS suppresses TNFα-induced adhesion molecule expression by blocking NF-κB signaling and inhibiting ROS generation in HUVECs. The results suggest that APS may be used to treat and prevent endothelial cell injury-related diseases.     

α-Hederin inhibits growth of lung cancer A549 cells in vitro and in vivo by decreasing c-Myc and HIF-1α dependent glycolysis

OBJECTIVE α-Hederin is an effective component of the traditional Chinese medicine Pulsatilla chinensis,which has been reported to exert many pharmacological activities. However, the effect of α-hederin on metabolism is still unclear. This study aimed to illuminate the role of α-hederin in glucose metabolism in lung cancer cells and investigate the molecular mechanism of α-hederin. METHODS CCK8 and colony formation assays were employed to assess the anti-proliferative effects induced by α-hederin. Glucose uptake, ATP generation, and reduced lactate production were measured using kits, and an A549 tumor xenograft mouse model of lung cancer was used to assess the in vivo antitumor effect of α-hederin(5, 10 mg·kg~(-1)). Glycolytic-related key enzymes were detected by Western blotting and immunohistochemical staining. RESULTS Cell proliferation was significantly inhibited by α-hederin in a dose-dependent manner and that α-hederin inhibited glucose uptake and ATP generation and reduced lactate production. Furthermore, α-hederin remarkably inhibited hexokinase 2(HK2), glucose transporters 1(GLUT1), pyruvate kinase M2(PKM2), lactate dehydrogenase A(LDHA), monocarboxylate transporter(MCT4), c-Myc, and hypoxia inducible factor-1α(HIF-1α) protein expression. Using inhibitors, we proved that α-hederin inhibits glycolysis by inhibiting glycolytic regulators. Moreover, a tumor xenograft mouse model of lung cancer further confirmed that α-hederin inhibits lung cancer growth via inhibiting glycolysisin vivo. CONCLUSION α-Hederin inhibits the growth of non-small cell lung cancer A549 cells by inhibiting glycolysis.The mechanism of glycolysis inhibition includes α-hederin inhibiting the expression of the glycolytic regulatory factors HIF-1α and c-Myc.     

Paeonol protects rat vascular endothelial cells from ox-LDL-induced injury in vitro via downregulating microRNA-21 expression and TNF-α release

Aim： Paeonol （2＇-hydroxy-4＇-methoxyacetophenone） from Cortex moutan root is a potential therapeutic agent for atherosclerosis. This study sought to investigate the mechanisms underlying anti-inflammatory effects of paeonol in rat vascular endothelial cells （VECs） in vitro.
Methods： VECs were isolated from rat thoracic aortas. The cells were pretreated with paeonol for 24 h, and then stimulated with ox-LDL for another 24 h. The expression of microRNA-21 （miR-21） and PTEN in VECs was analyzed using qRT-PCR. The expression of PTEN protein was detected by Western blotting. TNF-α release by VECs was measured by ELISA.

Results： Ox-LDL treatment inhibited VEC growth in dose- and time-dependent manners （the value of IC50 was about 20 mg/L at 24 h）. Furthermore, ox-LDL （20 mg/L） significantly increased miR-21 expression and inhibited the expression of PTEN, one of downstream target genes of miR-21 in VECs. In addition, ox-LDL （20 mg/L） significantly increased the release of TNF-α from VECs. Pretreatment with paeonol increased the survival rate of ox-LDL-treated VECs in dose- and time-dependent manners. Moreover, paeonol （120 μmol/L） prevented ox-LDL-induced increases in miR-21 expression and TNF-α release, and ox-LDL-induced inhibition in PTEN expression. A dual-luciferase reporter assay showed that miR-21 bound directly to PTEN＇s 3＇-UTR, thus inhibiting PTEN expression. In ox-LDL treated VECs, transfection with a miR-21 mimic significantly increased miR-21 expression and inhibited PTEN expression, and attenuated the protective effects of paeonol pretreatment, whereas transfection with an miR-21 inhibitor significantly decreased miR-21 expression and increased PTEN expression, thus enhanced the protective effects of paeonol pretreatment.

Conclusion： miR-21 is an important target of paeonol for its protective effects against ox-LDL-induced VEC injury, which may play critical roles in development of atherosclerosis.