Physiologically relevant curcuminoids inhibit angiogenesis via VEGFR2 in human aortic endothelial cells.

Angiogenesis is a complex process encompassing endothelial cell proliferation, migration, and tube formation. While numerous studies describe that curcumin exerts antitumor properties (e.g., targeting angiogenesis), information regarding other dietary curcuminoids such as demethoxycurcumin (DMC) and bisdemethoxycurcumin (BisDMC) is scant. In this study, we evaluated the antiangiogenic activities of these three curcuminoids at physiological concentrations (0.1-5 µM) on endothelial cell migration and tubulogenesis and the underlying associated mechanisms on human aortic endothelial cells (HAECs). Results showed that the individual compounds and a representative mixture inhibited the tubulogenic and migration capacity of endothelial cells dose-dependently, while sparing cell viability. Notably, DMC and BisDMC at 0.1 and 1 µM showed higher capacity than curcumin inhibiting tubulogenesis. These compounds also reduced phosphorylation of the VEGFR2 and the downstream ERK and Akt pathways in VEGF165-stimulated cells. In silico analysis showed that curcuminoids could bind the VEGFR2 antagonizing the VEGF-mediated angiogenesis. These findings suggest that physiologically concentrations of curcuminoids might counteract pro-angiogenic stimuli relevant to tumorigenic processes.

Apatinib Inhibits Angiogenesis in Intrahepatic Cholangiocarcinoma by Regulating the Vascular Endothelial Growth Factor Receptor-2/Signal Transducer and Activator of Transcription Factor 3/Hypoxia Inducible Factor 1 Subunit Alpha Signaling Axis.

INTRODUCTION: Intrahepatic cholangiocarcinoma (ICC), which is difficult to diagnose and is usually fatal due to its late clinical presentation and a lack of effective treatment, has risen over the past decades but without much improvement in prognosis. OBJECTIVE: The study aimed to investigate the role of apatinib that targets vascular endothelial growth factor receptor-2 (VEGFR2) in ICC. METHODS: MTT assays, cell scratch assays, and tube formation assays were used to assess the effect of apatinib on human ICC cell line (HuCCT-1) and RBE cells proliferation, migration, and angiogenic capacity, respectively. Expression of vascular endothelial growth factor (VEGF), VEGFR2, signal transducer and activator of transcription factor 3 (STAT3), pSTAT3, and hypoxia inducible factor 1 subunit alpha (HIF-1α) pathway proteins was assessed using Western blotting and mRNA expression analysis in HuCCT-1 was performed using RT-qPCR assays. The pcDNA 3.1(-)-VEGFR2 and pcDNA 3.1(-)-HIF-1α were transfected into HuCCT-1 and RBE cells using Lipofectamine 2,000 to obtain overexpressed HuCCT-1 and RBE cells. RESULTS: We found that apatinib-inhibited proliferation, migration, and angiogenesis of HuCCT-1 and RBE cells in vitro in a dose-dependent manner. We also proved that apatinib effectively inhibits angiogenesis in tumor cells by blocking the expression of VEGF and VEGFR2 in these cells. In addition, we demonstrated that apatinib regulates the expression of STAT3 phosphorylation by inhibiting VEGFR2. Finally, we showed that apatinib regulates ICC angiogenesis and HIF-1α/VEGF expression via STAT3. CONCLUSIONS: Based on the above findings, we conclude that apatinib inhibits HuCCT-1 and RBE cell proliferation, migration, and tumor angiogenesis by inhibiting the VEGFR2/STAT3/HIF-1α axis signaling pathway. Apatinib can be a promising drug for ICC-targeted molecular therapy.

CircCCT3 Acts as a Sponge of miR-613 to Promote Tumor Growth of Pancreatic Cancer Through Regulating VEGFA/VEGFR2 Signaling.

BACKGROUND: Circular RNAs (CircRNAs) have been recently implicated in the progression of pancreatic cancer (PC). AIMS: To investigate the involvement of CircCCT3 in PC and studying its interactions and functioning during the progression of PC in vitro and in vivo, using methods of molecular biology and bioinformatics. STUDY DESIGN: Experimental study. METHODS: The expressions of CircCCT3 and miR-613 in pancreatic carcinoma tissues and cell lines were evaluated by quantitative real-time polymerase chain reaction (PCR). The relationship between clinical pathologic features as well as the survival rate and CircCCT3 expression was analyzed with chi-square test and the Kaplan-Meier method. CCK-8, wound healing, transwell assays, and the fluorescein isothiocyanate- AnnexinV/propidium iodide (FITC-AnnexinV/PI) assay were used to assess cell proliferation, migration, invasion, and apoptosis after CircCCT3 overexpression or downregulation. The Dual- Luciferase reporter assay, RNA immunoprecipitation (RIP), RNA pull-down and fluorescence in situ hybridization (FISH) assays were performed to validate the potential interaction of CircCCT3, miR-613, and vascular endothelial growth factor (VEGFA). The nude mouse xenograft tumor assay was used to detect CircCCT3 effects on pancreatic tumorigenesis in vivo. Western blotting analysis was performed to examine the VEGFA and the vascular endothelial growth factor receptor 2 (VEGFR2) protein expressions following. RESULTS: CircCCT3 expression was significantly increased in PC tissues (3.41 ± 0.57 vs. 1.00 ± 0.10, P < .01) and cell lines (Patu8988 2.57 ± 0.20; SW1990 2.88 ± 0.10; BxPC-3 2.45 ± 0.20; Panc02 2.99 ± 0.10 vs. H6c7 1.00 ± 0.10; all P < .001). CircCCT3 expression was negatively correlated with miR-613 expression. PC patients with high CircCCT3 expression exhibited significantly poorer overall survival rate than those patients with low CircCCT3 expression (P = .013). Moreover, it was found that CircCCT3 promoted cell proliferation, migration, and invasion, and inhibited cell apoptosis in PC cells. The CircCCT3 acted as a sponge for the miR-613 to facilitate VEGFA and VEGFR2 expression. si-CirCCT3 also inhibited tumor growth of PC in nude mice. si-CircCCT3 reduced VEGFA and VEGFR2 expression, whereas overexpression of CircCCT3 increased VEGFA and VEGFR2 expression. CONCLUSION: Increased CircCCT3 suggests a poor prognosis for PC patients and promotes the migration and invasion through targeting VEGFA/VEGFR2 signaling. CircCCT3 may serve as a potential and promising therapeutic target for PC treatment.

Anti­angiogenic effect of mountain ginseng in vitro and in vivo: Comparison with farm­cultivated ginseng.

Mountain ginseng (Panax ginseng) has been used for cancer patient therapy in Northeast Asia. Although it is well known that cancer cells are able to induce angiogenesis, the effect of mountain ginseng on angiogenesis is still unknown. In the present study, we investigated whether ethanolic extract of mountain ginseng (MGE) could inhibit angiogenesis in in vitro and in vivo models. In comparison with farm­cultivated ginseng extract (FGE), MGE more strongly inhibited cell migration and formation of capillary­like network within non­cytotoxic ranges in SVEC4­10 cells. In addition, MGE dose­dependently suppressed Transwell cell migration of the cells. Moreover, MGE reduced the phosphorylation and expression of VEGF­R2 as well as the phosphorylation of FAK, Src, Akt and ERK, the intermediate proteins in the VEGF­R2 signaling cascade, in the cells. As expected, MGE dramatically decreased hemoglobin content in Matrigel plugs in mice. In conclusion, MGE possesses stronger anti­angiogenic properties than FGE in vascular endothelial cells. Such effect of MGE is correlated with inhibition of activation of the VEGF­R2 signaling pathway. Therefore, the novel features of MGE may be helpful for understanding its anticancer mechanism for the treatment of cancer patients.

Design, synthesis, molecular docking and anticancer evaluations of 5-benzylidenethiazolidine-2,4-dione derivatives targeting VEGFR-2 enzyme.

Novel series of 5-benzylidenethiazolidine-2,4-dione derivatives 4a-c-8a-f were designed, synthesized and evaluated for anticancer activity against HepG2, HCT-116 and MCF-7 cell lines. MCF-7 was the most sensitive cell line to the influence of the new derivatives. In particular, compound 8f was found to be the most potent derivative overall the tested compounds against the three HepG2, HCT116 and MCF-7 cancer cell lines with IC50 = 11.19 ± 0.8, 8.99 ± 0.7 and 7.10 ± 0.4 µM respectively. Compound 8f exhibited lower activity than sorafenib, (IC50 = 9.18 ± 0.6, 8.37 ± 0.7 and 5.10 ± 0.4 µM respectively), against HepG2 and HCT116 but exhibited nearly the same activity against MCF-7 cancer cell lines respectively. Also, this compound displayed lower activity than doxorubicin, (IC50 = 7.94 ± 0.6, 8.07 ± 0.8 and 6.75 ± 0.4 µM respectively), against HepG2 and HCT116 but nearly the same activity against MCF-7cell lines respectively. The most active derivatives 6c,d,f,g and 8a-f were evaluated for their inhibitory activities against VEGFR-2. The elongation of the structures to have distal moieties enhanced anticancer and VEGFR-2 inhibitory activities as in compounds 8a-f. Among them, compounds 8f was found to be the most potent derivative that inhibited VEGFR-2 at IC50 value of 0.22 ± 0.02 µM, which is nearly the half as that of sorafenib IC50 value (0.10 ± 0.02 µM). Furthermore, molecular design was performed to investigate their binding mode and affinities towards VEGFR-2 receptor. The data obtained from docking studies were highly correlated with that obtained from the biological screening.

Impact of deltamethrin selection on kdr mutations and insecticide detoxifying enzymes in Aedes aegypti from Mexico.

BACKGROUND: Insecticide resistance is a serious problem for vector control programmes worldwide. Resistance is commonly attributed to mutations at the insecticide's target site or increased activity of detoxification enzymes. METHODS: We determined the knockdown concentration (KC50) and lethal concentration (LC50) of deltamethrin in six natural populations of adult Aedes aegypti from southeastern Mexico. These populations were then selected over five generations using the LC50 from the preceding generation that underwent selection, and the heritability of deltamethrin resistance was quantified. For each generation, we also determined the frequency of the kdr alleles L410, I1016 and C1534, and the levels of activity of three enzyme families (α- and ß-esterases, mixed-function oxidases and glutathione S-transferases (GST)) associated with insecticide detoxification. RESULTS: There was an increase in KC50 and LC50 values in the subsequent generations of selection with deltamethrin (FS5vs FS0). According to the resistance ratios (RRs), we detected increases in LC50 ranging from 1.5 to 5.6 times the values of the parental generation and in KC50 ranging from 1.3-3.8 times the values of the parental generation. Triple homozygous mutant individuals (tri-locus, LL/II/CC) were present in the parental generations and increased in frequency after selection. The frequency of L410 increased from 1.18-fold to 2.63-fold after selection with deltamethrin (FS5vs FS0) in the populations analyzed; for I1016 an increase between 1.19-fold to 2.79-fold was observed, and C1534 was fixed in all populations after deltamethrin selection. Enzymatic activity varied significantly over the generations of selection. However, only α- esterase activity remained elevated in multiple populations after five generations of deltamethrin selection. We observed an increase in the mean activity levels of GSTs in two of the six populations analyzed. CONCLUSIONS: The high levels of resistance and their association with high frequencies of kdr mutations (V410L, V1016I and F1534C) obtained through artificial selection, suggest an important role of these mutations in conferring resistance to deltamethrin. We highlight the need to implement strategies that involve the monitoring of kdr frequencies in insecticide resistance monitoring and management programmes.

Apatinib Combined With Radiotherapy Enhances Antitumor Effects in an In Vivo Nasopharyngeal Carcinoma Model.

Vascular endothelial growth factor (VEGF) and its receptor (VEGFR) are highly expressed in nasopharyngeal carcinoma; therefore, blocking the binding of VEGF and VEGFR may be a potential way to treat nasopharyngeal carcinoma. Apatinib inhibits tumor angiogenesis. Previous studies have suggested that treatment with apatinib has an antitumor effect on nasopharyngeal carcinoma. This study will investigate the effect of apatinib combined with radiotherapy. In this study, nude mice injected with CNE-2 nasopharyngeal carcinoma cells were randomly divided into 6 groups. Therapeutic effects were assessed by evaluating tumor inhibition rate, phosphorylation of VEGFR-2, CD31, partial oxygen pressure, and tumor metabolism. We found that the tumor inhibition of mice in the treated groups was better compared to that of the control group. In mice treated with apatinib alone, angiogenesis was prevented, and the tumor tissue partial oxygen pressure was reduced, thereby achieving an antitumor effect. Moreover, the tumor inhibitory effect of combined treatment was stronger than treatment with either apatinib or radiotherapy alone. Compared with monotherapy treatment, combined treatment better resisted angiogenesis. Apatinib combined with radiotherapy to treat nasopharyngeal carcinoma has synergistic effects, which may be related to enhanced antiangiogenesis.

Bisphenol S Induces Ectopic Angiogenesis in Embryos via VEGFR2 Signaling, Leading to Lipid Deposition in Blood Vessels of Larval Zebrafish.

Bisphenol S (BPS), used as a bisphenol A substitute, has been detected in various environments. However, the safety of BPS is still unclear. Here, zebrafish embryos were exposed to BPS (0, 1, 10, and 100 µg/L) for 24, 48, 72, 96 h, and 15 days. BPS induced ectopic sprouting of budding blood vessels in embryos, but the blood flow velocity within these lesions was unchanged at 48 h. At 72 h postfertilization (hpf), by observing the subintestinal venous plexus responsible for yolk absorption, we found that VEGFR2 transduced an angiogenic signal and that the subsequent reduction in blood flow velocity inhibited yolk absorption. At 96 hpf, yolk consumption was still delayed because of the disturbed transportation route, resulting in transient extensive lipid retention in the blood vessels. After feeding, obvious atherogenic lipids were discovered in the blood vessels, especially in bends, bifurcations, and stenoses. This dynamic visualization of the pathogenesis demonstrates a plausible mechanistic link between BPS exposure-induced embryonic vessel overgrowth and an increased atherosclerosis risk.

Molecular dynamics simulation and 3D-pharmacophore analysis of new quinoline-based analogues with dual potential against EGFR and VEGFR-2.

Epidermal growth factor and vascular endothelial growth factor-2 are important targets of tyrosine kinase for the treatment of various cancerous diseases. Combination of inhibition of both targets to produce synergy in the signal pathway is a critical approach to identify novel tyrosine kinase inhibitors. In this study, a series of new compounds derived from the 4-aminoquinoline as dual inhibitors were synthesized. The obtained results of cytotoxicity assay against human carcinoma cell lines indicated 0.8 µM for 4c against A549 showing its high efficiency in comparison to erlotinib. Pharmacophore modeling as a structure-based method was investigated on dual inhibitors and 4c which was compared with co-crystallized in the active site of EGFR and VEGFR-2. They have shown the same binding orientation as vandetanib, erlotinib and sorafenib. Molecular dynamics simulation results approved that Met769, Lys721, Asp1046, and Lys868 are key residues in two binding sites for dual activity. Ala1050 and Pro968 were identified as new amino acid interaction sites for dual inhibition. 4c showed more favorable stability than vandetanib in VEGFR-2 receptor for a 50 ns dynamic simulation. The high correlation between essential pharmacophoric features of designed compounds and lead inhibitors interactions provided a deeper insight into the structural basis of 4-aminoquinoline inhibition.

Design, synthesis and biological evaluation of some new 1,3,4-thiadiazine-thiourea derivatives as potential antitumor agents against non-small cell lung cancer cells.

New 1,3,4-thiadiazine-thiourea derivatives have been synthesized. All the synthesized compounds were examined for in vitro cytotoxic activity against Non-Small Cell Lung Cancer (NSCLC) cell line A549, using MTT bioassay. Compounds 5d, 5i, 5j showed the highest cytotoxic activity with IC50 values of 0.27 ±â€¯0.01, 0.30 ±â€¯0.02, and 0.32 ±â€¯0.012 µM respectively with sorafenib as reference (IC50 3.85 ±â€¯0.27 µM). These compounds were chosen for further investigations against various biological targets known to play roles in NSCLC specifically: vascular endothelial growth factor receptor 2 (VEGFR2), B-RAF and matrix metalloproteinase 9 (MMP9). Encouraging results were exhibited by the three compounds against the selected targets. Compound 5j was specially promising as it exhibited inhibitory activity of VEGFR2 close to sorafenib (IC50 0.11 ±â€¯0.01 µM), most potent B-RAF activity inhibition (IC50 0.178 ±â€¯0.004 µM) and MMP9 inhibition (IC50 0.08 ±â€¯0.004 µM). Moreover, cell cycle analysis of A549 cells treated with 5j exhibited cell cycle arrest at G2-M phase and pro-apoptotic activity as indicated by Annexin V-FITC staining. Also, it reflected antinvasive and antimigration properties to A549 cells. Additionally, docking study of 5j on VEGFR2, B-RAF and MMP9 revealed that it binds to the target enzymes in a similar way as the co-crystallized ligand. The three compounds exhibited significantly high selectivity to A549 cancer cells against the normal human fetal lung fibroblast cell line WI-38 with higher selectivity index compared to sorafenib (5d IC50 136.76 ±â€¯2.38 µM, SI = 506.52; 5i IC50 89.20 ±â€¯2.11 µM, SI = 297.33; 5j IC50 79.60 ±â€¯3.8 µM, SI = 248.75; sorafenib IC50 30.32 ±â€¯2.41 µM, SI = 7.88). In conclusion, compounds 5d, 5i and 5j, specially 5j are promising anticancer agents targeting important pathways in NSCLC and warrant further preclinical and clinical trials.

Propofol attenuated TNF-α-modulated occludin expression by inhibiting Hif-1α/ VEGF/ VEGFR-2/ ERK signaling pathway in hCMEC/D3 cells.

BACKGROUND: The levels of tight junction proteins (TJs), especially occludin, correlate with blood-brain barrier (BBB) disruption caused by inflammation in central nervous system (CNS). It has been reported that propofol, the most commonly used anesthetic, could inhibit inflammation response in CNS. In this study, we investigated the effects of tumor necrosis factor-α (TNF-α) and propofol on occludin expression in human cerebral microvascular endothelial cell line, D3 clone (hCMEC/D3 cells), and explored the underlying mechanisms. METHODS: The hCMEC/D3 cells were treated with propofol, followed by TNF-α. The expression and phosphorylation of Hif-1α, VEGF, VEGFR-2, ERK, p38MAPK and occludin were measured by Western blot analysis. The cell viability of hCMEC/D3 cells was measured by cell counting kit-8. RESULTS: TNF-α (10 ng/ml, 4 h) significantly decreased the expression of occludin, which was attenuated by propofol (25 µM). TNF-α induced Hif-1α/VEGF/VEGFR-2/ERK signaling pathway, while propofol could inhibit it. TNF-α induced the phosphorylation of p38MAPK, while propofol had no effect on it. In addition, the inhibitors of Hif-1α, VEGFR-2, and ERK could reduce the effect of TNF-α on occludin expression. CONCLUSION: TNF-α could decrease the expression of occludin via activating Hif-1α/ VEGF/ VEGFR-2/ ERK signaling pathway, which was attenuated by propofol.

Is the effect of melatonin on vascular endothelial growth factor receptor-2 associated with angiogenesis in the rat ovary?

OBJECTIVES: Vascular endothelial growth factor (VEGF) and its receptors play important roles in angiogenesis. Melatonin plays an important role in gonadal development; thus, its effect on the reproductive system is evident. We investigated the influence of melatonin on the expression of VEGF, vascular endothelial growth factor receptor-1 (VEGFR1) and vascular endothelial growth factor receptor-2 (VEGFR2), as well as on changes in oxidative stress markers and follicle numbers in rat ovaries. METHODS: For this purpose, 45 Wistar rats were separated into the following groups: Group 1, control; Group 2, vehicle; and Group 3, melatonin. Rats in Group 3 were treated with melatonin at 50 mg/kg/day for 30 days. The effects of melatonin on the expression of VEGF, VEGFR1 and VEGFR2 were established by immunohistochemistry analysis. The effects of melatonin on antioxidant enzyme activities were demonstrated by spectrophotometric analysis. RESULTS: Based on immunohistochemistry analysis, VEGFR2 was predominantly localized to theca cells in the ovary. Our data indicate that melatonin treatment can significantly increase VEGF and VEGFR1 expression in the ovary ( p <0.05). Additionally, the number of degenerated follicles significantly decreased with melatonin treatment ( p <0.05). Melatonin administration also led to significant increases in antioxidant enzyme levels in the ovary. CONCLUSION: Melatonin treatment exerts protective effects on follicles against increased lipid peroxidation through modulating tissue antioxidant enzyme levels. These effects may be related to angiogenesis and antioxidant activities.

Roxadustat promotes angiogenesis through HIF-1α/VEGF/VEGFR2 signaling and accelerates cutaneous wound healing in diabetic rats.

Diabetic foot ulcers are a major health-care burden worldwide. One primary cause of the delayed wound healing in diabetic patients is impaired function of the hypoxia-inducible factor-1α/vascular endothelial growth factor (HIF-1α/VEGF) axis, which results in compromised neovascularization in response to hypoxia. In the present study, we aimed to investigate the effect of roxadustat, a novel HIF prolyl-4-hydroxylase inhibitor, on angiogenesis and its therapeutic effect on cutaneous wound healing in diabetic rats. In vitro, we found that roxadustat could promote the angiogenic activity of human umbilical vein endothelial cells, accompanied by up-regulation of HIF-1α/VEGF/VEGFR2 signaling. Next, we demonstrated that Ki8751, a VEGFR2-specific inhibitor, could inhibit the increased angiogenic activity of human umbilical vein endothelial cells induced by roxadustat. In vivo, we performed a Matrigel plug assay and demonstrated that roxadustat induced vascularization of the Matrigel plugs, and this effect could be partially inhibited by Ki8751. Finally, we utilized a streptozotocin-induced diabetic rat model and found that roxadustat could accelerate cutaneous wound healing and promote angiogenesis in the wound sites. In conclusion, roxadustat promotes angiogenesis via activation of the HIF-1α/VEGF/VEGFR2 pathway and exhibits therapeutic effects on diabetic wound healing by increasing angiogenesis. Our findings suggest that roxadustat can be a promising strategy to promote diabetic cutaneous wound healing.

Design and Synthesis of 1,2-Bis(hydroxymethyl)pyrrolo[2,1- a]phthalazine Hybrids as Potent Anticancer Agents that Inhibit Angiogenesis and Induce DNA Interstrand Cross-links.

Hybrid molecules are composed of two pharmacophores with different biological activities. Here, we conjugated phthalazine moieties (antiangiogenetic pharmacophore) and bis(hydroxymethyl)pyrrole moieties (DNA cross-linking agent) to form a series of bis(hydroxymethyl)pyrrolo[2,1- a]phthalazine hybrids. These conjugates were cytotoxic to a variety of cancer cell lines by inducing DNA damage, arresting cell cycle progression at the G2/M phase, triggering apoptosis, and inhibiting vascular endothelial growth factor receptor 2 (VEGFR-2) in endothelial cells. Among them, compound 29d encapsulated in a liposomal formulation (e.g., 29dL) significantly suppressed the growth of small-cell lung cancer cell (H526) xenografts in mice. Based on immunohistochemical staining, the tumor xenografts in mice treated with 29dL showed time-dependent decreases in the intensity of CD31, a marker of blood vessels, whereas the intensity of γ-H2AX, a marker of DNA damage, increased. The present data revealed that the conjugation of antiangiogenic and DNA-damaging agents can generate potential hybrid agents for cancer treatment.

Role of Neuronal VEGF Signaling in the Prefrontal Cortex in the Rapid Antidepressant Effects of Ketamine.

OBJECTIVE: The N-methyl-d-aspartate receptor antagonist ketamine produces rapid and sustained antidepressant actions even in patients with treatment-resistant depression. Vascular endothelial growth factor (VEGF) has been implicated in the effects of conventional monoamine-based antidepressants, but the role of VEGF in the rapid antidepressant actions of ketamine remains unclear. The authors examined whether neuronal VEGF signaling in the medial prefrontal cortex (mPFC) mediates the rapid antidepressant actions of ketamine. METHODS: The authors used a combination of approaches, including conditional, neuron-specific knockout of VEGF or its receptor, Flk-1; antibody neutralization; viral-mediated knockdown of Flk-1; and pharmacological inhibitors. Further in vitro and in vivo experiments were performed to examine whether neuronal VEGF signaling was required for the neurotrophic and synaptogenic actions of ketamine that underlie its behavioral actions. RESULTS: The behavioral actions of systemic ketamine are blocked by forebrain excitatory neuron-specific deletion of either VEGF or Flk-1 or by intra-mPFC infusion of a VEGF neutralizing antibody. Moreover, intra-mPFC infusions of VEGF are sufficient to produce rapid ketamine-like behavioral actions, and these effects are blocked by neuron-specific Flk-1 deletion. The results also show that local knockdown of Flk-1 in mPFC excitatory neurons in adulthood blocks the behavioral effects of systemic ketamine. Moreover, inhibition of neuronal VEGF signaling blocks the neurotrophic and synaptogenic effects of ketamine. CONCLUSIONS: Together, these findings indicate that neuronal VEGF-Flk-1 signaling in the mPFC plays an essential role in the antidepressant actions of ketamine.

Is the effect of melatonin on vascular endothelial growth factor receptor-2 associated with angiogenesis in the rat ovary?

OBJECTIVES Vascular endothelial growth factor (VEGF) and its receptors play important roles in angiogenesis. Melatonin plays an important role in gonadal development; thus, its effect on the reproductive system is evident. We investigated the influence of melatonin on the expression of VEGF, vascular endothelial growth factor receptor-1 (VEGFR1) and vascular endothelial growth factor receptor-2 (VEGFR2), as well as on changes in oxidative stress markers and follicle numbers in rat ovaries. METHODS For this purpose, 45 Wistar rats were separated into the following groups: Group 1, control; Group 2, vehicle; and Group 3, melatonin. Rats in Group 3 were treated with melatonin at 50 mg/kg/day for 30 days. The effects of melatonin on the expression of VEGF, VEGFR1 and VEGFR2 were established by immunohistochemistry analysis. The effects of melatonin on antioxidant enzyme activities were demonstrated by spectrophotometric analysis. RESULTS Based on immunohistochemistry analysis, VEGFR2 was predominantly localized to theca cells in the ovary. Our data indicate that melatonin treatment can significantly increase VEGF and VEGFR1 expression in the ovary ( p <0.05). Additionally, the number of degenerated follicles significantly decreased with melatonin treatment ( p <0.05). Melatonin administration also led to significant increases in antioxidant enzyme levels in the ovary. CONCLUSION Melatonin treatment exerts protective effects on follicles against increased lipid peroxidation through modulating tissue antioxidant enzyme levels. These effects may be related to angiogenesis and antioxidant activities.

Expresión de VEGF-A y VEGFR2 en Miocardio de Pollos Tratados con Ácido Acetilsalicílico (AAS) / VEGF-A and VEGFR2 Expression in Chicken Myocardium Treated with Acetylsalicylic Acid (AAS)

RESUMEN: Los niveles de VEGF y su unión a sus receptores son etapas claves en la regulación de la angiogénesis. El ácido acetilsalicílico (AAS), ampliamente utilizado en tratamiento post infarto al miocardio ha mostrado poseer un efecto antiangiogénico en modelos tumorales. Este efecto potencialmente contraproducente requiere ser estudiado en miocardio. El objetivo del presente trabajo es cuantificar el efecto de AAS y de ácido salicílico (AS) sobre la vascularización en membrana alantocoriónica (MAC) y sobre los niveles de VEGF-A y VEGFR2 en miocardio de embriones de pollo. Para ello, treinta fetos de pollo White Leghorn fueron instilados a los 10 días de gestación con 60 µL de DMSO 0,1 % (control) o conteniendo además 0,3 µmol de AAS o AS. A las 48 horas se realizó procesamiento histológico de MAC para recuento de vasos sanguíneos y de tejido cardíaco para cuantificar VEGF-A y VEGFR2 por inmunohistoquímica. La inmunorreactividad fue cuantificada mediante Image J. Tanto AAS como AS disminuyeron la densidad microvascular de MAC. En miocardio, AAS aunque no AS, disminuyó la concentración de VEGFR2. No hubo efecto sobre VEGF-A. En nuestro modelo experimental, fetos de pollo a los 10 días de gestación también se observó el efecto inhibidor de AAS sobre la angiogénesis en MAC. La disminución de VEGFR2 en cardiomiocitos sugiere que AAS también afecta la angiogénesis en miocardio sano, modificando la disponibilidad del receptor a VEGF. Estos hallazgos nos permiten postular que AAS podría interferir con la regeneración de tejido, en situaciones como post infarto al miocardio.

SUMMARY: The VEGF levels and its binding to its receptors are key stages in the regulation of angiogenesis. Acetylsalicylic acid (ASA), widely used in post-myocardial infarction treatment, has been shown to have an anti-angiogenic effect in tumor models. This potentially counterproductive effect requires to be studied in myocardium. The aim of this study is to quantify the effect of ASA and salicylic acid (SA) on the vascularization in chick allantochorionic membrane (CAM) and on the levels of VEGF-A and VEGFR2 in myocardium of chicken embryos. Thirty White Leghorn chicken fetuses were instilled at 10 days of gestation with 60 mL of 0.1 % DMSO (control) or also containing 0.3 mmol of ASA or SA. After 48 hours, CAM histological processing was performed to count blood vessels and heart tissue to quantify VEGFA and VEGFR2 by immunohistochemistry. Immunoreactivity was quantified by Image J. Both ASA and SA decreased CAM microvascular density. In myocardium, AAS, although not SA, decreased the concentration of VEGFR2. There was no effect on VEGF-A. In our experimental model, chicken fetuses at 10 days of gestation, the inhibitory effect of ASA on angiogenesis in CAM were also observed. The decrease in VEGFR2 in cardiomyocytes suggests that ASA also affects angiogenesis in healthy myocardium, modifying the availability of the receptor to VEGF. These findings allow us to postulate that ASA could interfere with tissue regeneration, when it is required, as post myocardial infarction.

Aspirin Affects Tumor Angiogenesis and Sensitizes Human Glioblastoma Endothelial Cells to Temozolomide, Bevacizumab, and Sunitinib, Impairing Vascular Endothelial Growth Factor-Related Signaling.

BACKGROUND: Glioblastoma (GBM) is the most common and fatal human brain tumor, with the worst prognosis. The aberrant microenvironment, enhanced by the activation of proangiogenic mediators such as hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF), and their downstream effectors, sustain GBM malignancy. Proangiogenic signaling represents an attractive chemotherapeutic target. Recent evidence suggests a therapeutic benefit from aspirin (acetylsalicylic acid, or ASA) intake in reducing risk and cancer progression. METHODS: In the present study, human primary GBM-endothelial cells (ECs) were used to ascertain whether ASA could inhibit angiogenesis and improve cell sensitivity to drugs. The impact of ASA was observed by measuring cell viability, tube-like structure formation, migration, VEGF production, and proliferative, proangiogenic, and apoptotic modulators expression, such as HIF-1α/VEGF/vascular endothelial growth factor receptor/(VEGFR)-1/VEGFR-2, Ras/mitogen-activated protein kinase kinase/extracellular signal-regulated kinase, phosphoinositide 3-kinase/AKT signaling axis, and Bcl-2-associated X protein/B-cell lymphoma 2 (BCL-2) ratio. Furthermore, we evaluated the effect of ASA alone or in combination with temozolomide (TMZ), bevacizumab (BEV), and sunitinib (SUN). RESULTS: Our data reported that ASA affected GBM-EC viability, tube-like structure formation, cell migration, and VEGF releasing in a dose-dependent manner and that combined treatments with TMZ, BEV, and SUN synergized to counteract proangiogenic cell ability. mRNA expression analysis displayed a marked effect of ASA in reducing VEGF, VEGFR-1, HIF-1α, RAS, mitogen-activated protein kinase kinase, AKT, and BCL-2, as well a combined anticancer effect of ASA together with TMZ, BEV, and SUN. Levels of HIF-1α, VEGFR-2, Bcl-2-associated X protein, and BCL-2 protein expression confirmed a positive trend. CONCLUSIONS: ASA and antiangiogenic therapies showed synergetic anticancer efficacy in human primary GBM-ECs. Thus, the combination of conventional chemotherapy with ASA may offer a new strategy to counteract tumor malignancy.

Pioglitazone Induces Cardiomyocyte Apoptosis and Inhibits Cardiomyocyte Hypertrophy Via VEGFR-2 Signaling Pathway / Pioglitazona Induz Apoptose e Inibe Hipertrofia de Cardiomiócitos pela Via de Sinalização do VEGFR-2

Abstract Background: Pioglitazone has been widely used as an insulin-sensitizing agent for improving glycemic control in patients with type 2 diabetes mellitus. However, cardiovascular risk and protective effects of pioglitazone remain controversial. Objectives: In this study, we investigated whether pioglitazone affects cardiomyocyte apoptosis and hypertrophy by regulating the VEGFR-2 signaling pathway. Methods: Cardiomyocytes were enzymatically isolated from 1- to 3-day-old Sprague-Dawley rat ventricles. Effects of pioglitazone and the VEGFR-2-selective inhibitor apatinib on cardiomyocyte apoptotic rate was determined using flow cytometry, and hypertrophy was evaluated using [3H]-leucine incorporation. The protein expressions of unphosphorylated and phosphorylated VEGFR-2, Akt, P53, and mTOR were determined by Western-Blotting. Analysis of variance (ANOVA) was used to assess the differences between groups. Results: Pioglitazone and VEGFR-2-selective inhibitor apatinib reduced rat cardiomyocyte viability and cardiomyocyte hypertrophy induced by angiotensin II in vitro. Furthermore, in the same in vitro model, pioglitazone and apatinib significantly increased the expression of Bax and phosphorylated P53 and decreased the expression of phosphorylated VEGFR-2, Akt, and mTOR, which promote cardiomyocyte hypertrophy. Conclusions: These findings indicate that pioglitazone induces cardiomyocyte apoptosis and inhibits cardiomyocyte hypertrophy by modulating the VEGFR-2 signaling pathway.

Resumo Fundamento: A pioglitazona tem sido amplamente utilizada como droga sensibilizadora da insulina para melhorar o controle glicêmico em pacientes com diabetes mellitus tipo 2. No entanto, o risco cardiovascular bem como os efeitos protetores da pioglitazona ainda são controversos. Objetivos: Neste estudo, investigamos se os efeitos da pioglitazona sobre a apoptose e a hipertrofia de cardiomiócitos ocorrem via regulação da via de sinalização do VEGFR-2. Métodos: os cardiomiócitos foram isolados enzimaticamente dos ventrículos de ratos Sprague-Dawley de 1-3 anos de vida. Os efeitos da pioglitazona e do inibidor seletivo de VEGFR-2 apatinib sobre a taxa de apoptose dos cardiomiócitos foram avaliados por citometria de fluxo, e a hipertrofia avaliada por incorporação de leucina-[3H]. As expressões de VEGFR-2, Akt, P53, e mTOR fosforiladas e não fosforiladas foram determinadas por Western Blotting. Análise de variância (ANOVA) foi usada para avaliar diferenças entre os grupos. Resultados: a pioglitazona e o apatinib reduziram a viabilidade e a hipertrofia de cardiomiócitos induzida por angiotensina II in vitro. Além disso, no mesmo modelo in vitro, a pioglitazona e o apatinib aumentaram significativamente a expressão de Bax e P53 fosforilada, e diminuiu a expressão de VEGFR-2, Akt, e mTOR, que promove hipertrofia de cardiomiócitos. Conclusões: Esses resultados indicam que a pioglitazona induz a apoptose e inibe a hipertrofia de cardiomiócitos pela modulação da via de sinalização de VEGFR-2.