Vascular Endothelial Growth Factor Receptor 2 Expression Research Articles

The in vitro effect of VEGF receptor inhibition on primary alveolar osteoblast nodule formation.

Vascular endothelial growth factor (VEGF) is a master regulator and is required for the effective coupling of angiogenesis and osteogenesis supporting both skeletal development and postnatal bone repair. A direct role for VEGF in intramembranous-derived osteoblast growth and differentiation is not clear. We investigated the expression of primary alveolar osteoblast VEGF receptors and the subsequent effects on mineralization and nodule formation in vitro following VEGFR inhibition. Primary human alveolar osteoblasts (HAOBs) were cultured in the presence of VEGF receptor inhibitors, exogenous VEGF or the bisphosphonate, zoledronic acid. VEGF, VEGFR1 and VEGFR2 mRNA expression and nodule formation following 21days of culture. VEGFR1 protein expression was examined using immunofluorescence after 48h. The HAOBs expressed high levels of VEGF and VEGFR1 protein but VEGFR2 was not detected. The VEGFR1/2 inhibitors, ZM306416 and KRN633, lead to a dose-dependent decrease in mineralization. Treatment with zoledronic acid showed no difference in HAOB VEGF receptor expression. VEGF/VEGFR1 pathway appears to be important for intramembranous-derived osteoblast differentiation and maturation in vitro.

Antitumor effect of VEGFR2-targeted microbubble destruction with gemcitabine using an endoscopic ultrasound probe: In vivo mouse pancreatic ductal adenocarcinoma model

BackgroundUltrasound-targeted microbubble destruction (UTMD) induces cellular inflow of drugs at low intensity, while high intensity eradicates tumor vessels. Since vascular endothelial growth factor receptor 2 (VEGFR2) is highly expressed in pancreatic ductal adenocarcinoma (PDAC), VEGFR2-targeted microbubble (MB) might additionally increase the tissue specificity of drugs and thus improve antitumor effects. In addition, fixing the dual pulse intensity could maximize MB properties. This study evaluated the one-off (experiment 1) and cumulative (experiment 2) treatment effect of UTMD by regulating the dual pulse output applied to PDAC using VEGFR2-targeted MB. MethodsC57BL/6 mice inoculated with Pan-02 cells were allocated to five groups: VEGFR2-targeted MB+ gemcitabine (GEM), VEGFR2-targeted MB, non-targeted MB+GEM, GEM, and control groups. After injection of GEM or GEM and either VEGFR2-targeted or non-targeted MB, UTMD was applied for several minutes at low intensity followed by high intensity application. In experiment 1, mice were treated by the protocol described above and then euthanized immediately or at the tumor diameter doubling time (TDT). In experiment 2, the same protocol was repeated weekly and mice were euthanized at TDT regardless of protocol completion. Histological analysis by CD31 and VEGFR2 staining provided microvascular density (MVD) and VEGFR2 expression along vessels (VEGFR2v) or intra/peripheral cells (VEGFR2c). ResultsIn experiment 1, TDT was significantly longer in the VEGFR2-targeted MB+GEM group compared to the non-targeted MB+GEM, GEM, and control groups, while the VEGFR2-targeted MB group showed no statistical significance. MVD and VEGFR2v in the immediate euthanasia was significantly lower in the VEGFR2-targeted MB+GEM and VEGFR2-targeted MB groups than other conditions. In experiment 2, the VEGFR2-targeted MB+GEM group produced significantly longer TDT than the GEM or control groups, whereas the VEGFR2-targeted MB group showed no significant difference. Histology revealed significantly reduced VEGFR2v and VEGFR2c in the VEGFR2-targeted and non-targeted MB+GEM groups, while only VEGFR2v was significantly less in the VEGFR2-targeted MB group. ConclusionsUTMD-mediated GEM therapy with the dual pulse application using VEGFR2-targeted MB substantially suppresses PDCA growth.

核蛋白14对黑素瘤新生血管形成的影响及机制研究

Objective To evaluate the effect of nucleolar protein 14 (NOP14) on angiogenesis in melanoma. Methods Melanoma tissues were collected from 40 patients with pathologically diagnosed melanoma in Guangzhou First People′s Hospital from January 2016 to December 2018, and immunohistochemical study was conducted to determine the expression of NOP14 and CD31 (expressed as microvessel density [MVD]) . Melanoma cell lines A375 and SK-MEL-1 were both divided into 4 groups: empty vector group transfected with the empty vector, NOP14 group transfected with a NOP14-overexpressing vector, siNOP14 group transfected with the siRNA targeting NOP14, and siNC group transfected with a negative control siRNA. Fluorescence-based quantitative PCR and Western blot analysis were performed to determine the mRNA and protein expression of NOP14 respectively, and Western blot analysis and enzyme-linked immunosorbent assay (ELISA) to measure the expression of vascular endothelial growth factor (VEGF) and VEGF receptor (VEGFR) in cells and their culture media. Co-culture models of human umbilical vein endothelial cells (HUVECs) and A375/SK-MEL-1 cells in the above groups were established in Transwell chambers, and cell counting kit-8 (CCK8) assay, Transwell migration and invasion assays and Matrigel-based vasculogenic mimicry assay were performed to evaluate the cellular proliferative, migratory, invasive activity and tube formation capacity respectively. A linear regression model was used to analyze the relationship between NOP14 expression and MVD in melanoma tissues, multi-way analysis of variance to analyze the difference in cellular proliferative activity, and independent-sample t test to compare other experimental indices between 2 groups. Results The expression of CD31 (MVD) was 44 ± 13 in the group with high NOP14 expression (n = 20) , 58 ± 16 in that with moderate NOP14 expression (n = 17) , and 62 ± 11 in that with low NOP14 expression (n = 3) . The NOP14 expression was negatively correlated with MVD (r = - 0.525, P = 0.017) . Compared with the empty vector group, the expression of VEGF and VEGFR in A375 and SK-MEL-1 cells and their culture media significantly decreased in the NOP14 group (all P < 0.05) . Compared with the siNC group, the expression of VEGF and VEGFR in the A375 and SK-MEL-1 cells and their culture media significantly increased in the siNOP14 group (all P < 0.05) . In the co-culture models of A375 cells and HUVECs, the NOP14 group showed significantly decreased proliferative activity of HUVECs (F = 131.85, P < 0.05) , and numbers of migratory cells (22 ± 5 vs. 63 ± 8, t = 7.07, P = 0.002) , invasive cells (14 ± 5 vs. 45 ± 10, t = 4.94, P = 0.008) and branch points (8 ± 2 vs. 14 ± 3, t = 5.06, P < 0.001) compared with the empty vector group; compared with the siNC group, the siNOP14 group showed significantly increased proliferative activity of HUVECs (F = 79.92, P < 0.01) , and numbers of migratory cells (152 ± 30 vs. 59 ± 4, t = 5.36, P = 0.006) , invasive cells (134 ± 21 vs. 50 ± 8, t = 6.40, P < 0.001) and branch points (27 ± 3 vs. 15 ± 4, t = 6.10, P < 0.001) . In the co-culture models of SK-MEL-1 cells and HUVECs, the 4 groups showed the same trend of changes in the cellular proliferative, migratory, invasive activity and tube formation capacity of HUVECs as the above groups in the co-culture models of A375 cells and HUVECs. Conclusion The NOP14 expression is negatively correlated with MVD in melanoma tissues, and NOP14 can inhibit angiogenesis in melanoma. Key words: Nevi and melanomas; Melanoma, experimental; Nuclear proteins; Angiogenesis inhibitors; Cell proliferation; Cell movement; Nucleolar protein 14

Apatinib Inhibits Cell Proliferation and Induces Autophagy in Human Papillary Thyroid Carcinoma via the PI3K/Akt/mTOR Signaling Pathway

Background: Patients with metastatic radioiodine-refractory papillary thyroid carcinoma (PTC) have limited treatment options and a poor prognosis. There is an urgent need to develop new drugs targeting PTC for clinical application. Apatinib, a novel small-molecule tyrosine kinase inhibitor (TKI), is highly selective for vascular endothelial growth factor receptor-2 (VEGFR2) and exhibits antitumor effects in a variety of solid tumors. Although apatinib has been shown to be safe and efficacious in radioiodine-refractory differentiated thyroid cancer, the mechanism underlying its antitumor effect is unclear. In this report, we explored the effects of apatinib on PTC in vitro and in vivo.Methods: VEGFR2 expression levels were evaluated by immunohistochemistry (IHC), qPCR, and western blotting (WB). The effects of apatinib on cell viability, colony formation, and migration in the Transwell assay were assessed in vitro, and its effect on tumor growth rate was assessed in vivo. In addition, the levels of proteins in signaling pathways were determined by WB. Finally, the autophagy level was assessed by WB, immunofluorescence (IF), and transmission electron microscopy.Results: We found that high VEGFR2 expression is associated with tumor size, T stage, and lymph node metastasis in patients with PTC and that apatinib inhibits PTC cell growth, promotes apoptosis, and induces cell cycle arrest through the PI3K/Akt/mTOR signaling pathway. Moreover, apatinib induces autophagy, and pharmacological inhibition of autophagy or small interfering RNA (siRNA)-mediated targeting of autophagy-associated gene 5 (ATG5) can further increase PTC cell apoptosis.Conclusion: Our data suggest that apatinib can induce apoptosis and autophagy via the PI3K/Akt/mTOR signaling pathway for the treatment of PTC and that autophagy is a potential novel target for future therapy in resistant PTC.

Anti-angiogenic effect of a chemically sulfated polysaccharide from Phellinus ribis by inhibiting VEGF/VEGFR pathway

Previous studies have demonstrated that the sulfated polysaccharide named PRP-S16 could inhibit the proliferation, migration, and tube formation of endothelial cells in vitro. Here, its anti-angiogenic effect and mechanism in vivo were investigated by Lewis lung carcinoma (LLC) mice model. PRP-S16 significantly reduced the microvessel density (MVD) of tumor, exhibiting a high tumor growth inhibitory effect in LLC mice. All designed assays including quantitative real-time PCR, immunohistochemistry, enzyme-linked immunosorbent assay and western blotting showed that PRP-S16 reduced the mRNA and the protein expression of vascular endothelial growth factor (VEGF) and VEGF receptor-2 (VEGFR-2) in serum or tumor tissue of mice. Western blotting also detected decreased phosphorylated (p)-VEGFR-1, p-VEGFR-2, hypoxia-inducible factor-1α (HIF-1α), protein kinase B (Akt), and matrix metalloproteinases-9 (MMP-9). PRP-S16 had no adverse effects on angiogenesis in non-target organs. These findings suggested that the mechanism of anti-angiogenesis of PRP-S16 in vivo was due to inhibition of VEGF/VEGFR signaling pathway and it might be a promising candidate for tumor by anti-angiogenic therapy.

Androgens Stimulate EPC-Mediated Neovascularization and Are Associated with Increased Coronary Collateralization.

Endothelial progenitor cells (EPCs) play a key role in neovascularization and have been linked to improved cardiovascular outcomes. Although there is a well-established inverse relationship between androgen levels and cardiovascular mortality in men, the role of androgens in EPC function is not fully understood. In this study, we investigated the effects of androgens on 2 subpopulations of EPCs, early EPCs (EEPCs) and late outgrowth EPCs (OECs), and their relationships with coronary collateralization. Early EPCs and OECs were isolated from the peripheral blood of young healthy men and treated with dihydrotestosterone (DHT) with or without androgen receptor (AR) antagonist, hydroxyflutamide, in vitro. Dihydrotestosterone treatment enhanced AR-mediated proliferation, migration, and tubulogenesis of EEPCs and OECs in a dose-dependent manner. Furthermore, DHT augmented EPC sensitivity to extracellular stimulation by vascular endothelial growth factor (VEGF) via increased surface VEGF receptor expression and AKT activation. In vivo, xenotransplantation of DHT pretreated human EPCs augmented blood flow recovery and angiogenesis in BALB/c nude male mice, compared to mice receiving untreated EPCs, following hindlimb ischemia. In particular, DHT pretreated human OECs exhibited higher reparative potential than EEPCs in augmenting postischemic blood flow recovery in mice. Furthermore, whole blood was collected from the coronary sinus of men with single vessel coronary artery disease (CAD) who underwent elective percutaneous intervention (n = 23). Coronary collateralization was assessed using the collateral flow index. Serum testosterone and EPC levels were measured. In men with CAD, circulating testosterone was positively associated with the extent of coronary collateralization and the levels of OECs. In conclusion, androgens enhance EPC function and promote neovascularization after ischemia in mice and are associated with coronary collateralization in men.

Regorafenib sensitizes human breast cancer cells to radiation by inhibiting multiple kinases and inducing DNA damage

Purpose Triple-negative breast cancer (TNBC) is the most challenging and aggressive subtype of breast cancer with limited treatment options because of tumor heterogeneity, lack of druggable targets and therapy resistance. TNBCs are characterized by overexpression of growth factor receptors such as epidermal growth factor receptor (EGFR), vascular endothelial growth factor receptor (VEGFR), and platelet derived growth factor receptor (PDGFR) making them promising therapeutic targets. Regorafenib is an FDA approved oral multi-kinase inhibitor that blocks the activity of multiple protein kinases including those involved in the regulation of tumor angiogenesis [VEGFR1-3, TIE2], tumor microenvironment [PDGFR-β, FGFR] and oncogenesis (KIT, RET, RAF-1, BRAF). In the current study, we examined the radiosensitizing effects of Regorafenib on TNBC cell lines and explored the mechanism by which Regorafenib enhances radiosensitivity. Methods MDA-MB-231 and SUM159PT (human TNBC cell lines) and MCF 10a (human mammary epithelial cell line) were treated with Regorafenib, ionizing radiation or a combination of both. Following treatment with Regorafenib and radiation we conducted clonogenic assay to determine radiosensitivity, immunoblot analysis to assess the effect on key signaling targets, tube formation to evaluate effect on angiogenesis and comet assay as well as western blot for γH2AX to assess DNA damage response (DDR). Results Regorafenib reduced cell proliferation and enhanced radiosensitivity of MDA-MB-231 and SUM159PT cell lines but had no effect on the MCF 10a cells. Clonogenic survival assays showed that the surviving fraction at 2 Gy for both MDA-MB-231 and SUM159PT was reduced from 66.4 ± 8.9 and 88.2 ± 1.7 in controls to 38.1 ± 4.9 and 75.1 ± 1.1 following a 24 hr pretreatment with 10 μM and 5 μM Regorafenib, respectively. A marked reduction in the expression of VEGFR, PDGFR, EGFR and the downstream target, ERK, was observed with Regorafenib treatment alone or in combination with radiation. We also observed a significant inhibition of VEGF-A production in the TNBC cell lines following treatment with Regorafenib. Further, the addition of conditioned medium from Regorafenib-treated tumor cells onto human umbilical vein endothelial cells (HUVEC) suppressed tube formation, indicating an inhibition of tumor angiogenesis. Regorafenib also decreased migration of TNBC cells and suppressed radiation-induced DNA damage repair in a time-dependent manner. Conclusions Our findings demonstrate that Regorafenib enhanced radiosensitivity of breast cancer cells by inhibiting the expression of multiple receptor tyrosine kinases, VEGF-mediated angiogenesis and DNA damage response in TNBC. Therefore, combining Regorafenib with radiation and antiangiogenic agents will be beneficial and effective in controlling TNBC.

Skeletal restoration by phosphodiesterase 5 inhibitors in osteopenic mice: Evidence of osteoanabolic and osteoangiogenic effects of the drugs.

Phosphodiesterases (PDEs) hydrolyze cyclic nucleotides and thereby regulate diverse cellular functions. The reports on the skeletal effects of PDE inhibitors are conflicting. Here, we screened 17 clinically used non-xanthine PDE inhibitors (selective and non-selective) using mouse calvarial osteoblasts (MCO) where the readout was osteoblast differentiation. From this screen, we identified sildenafil and vardenafil (both PDE5 inhibitors) having the least osteogenic EC50. Both drugs significantly increased vascular endothelial growth factor (VEGF) and VEGF receptor 2 (VEGFR2) expressions in MCO and the nitric oxide synthase inhibitor L-NAME completely blocked VEGF expression induced by these drugs. Sunitinib, a tyrosine receptor kinase inhibitor that also blocks VEGFR2 blocked sildenafil-/vardenafil-induced osteoblast differentiation. At half of their human equivalent doses, i.e. 6.0mg/kg sildenafil and 2.5mg/kg vardenafil, the maximum bone marrow level of sildenafil was 32% and vardenafil was 21% of their blood levels. At these doses, both drugs enhanced bone regeneration at the femur osteotomy site and completely restored bone mass, microarchitecture, and strength in OVX mice. Furthermore, both drugs increased surface referent bone formation and serum bone formation marker (P1NP) without affecting the resorption marker (CTX-1). Both drugs increased the expression of VEGF and VEGFR2 in bones and osteoblasts and increased skeletal vascularity. Sunitinib completely blocked the bone restorative and vascular effects of sildenafil and vardenafil in OVX mice. Taken together, our study suggested that sildenafil and vardenafil at half of their adult human doses completely reversed osteopenia in OVX mice by an osteogenic mechanism that was associated with enhanced skeletal vascularity.

Curcumin stimulates angiogenesis through VEGF and expression of HLA‐G in first‐trimester human placental trophoblasts

Curcumin has a protective role in placental diseases like preeclampsia and preterm birth. Very little is known about its functional effects on growth, angiogenesis, and epigenetic activities of human first trimester placenta. HTR8/SVneo trophoblasts cells were used as model for human first trimester placenta. Effects of curcumin (≥80%) in these cells were investigated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), radioactive thymidine uptake, quantitative real-time polymerase chain reaction (qRT-PCR), promoter DNA methylation, qRT-PCR array, tube formation, wound healing, and immunoblot assays. PC3 (prostate cancer), JEG-3 (trophoblast), and HMEC-1 (endothelial) cells were used as control in various experiments. Unlike in PC3 cells, curcumin stimulated growth, proliferation, and viability in HTR8/SVneo cells. Curcumin increased tube formation, and messenger RNA (mRNA) expression of angiogenic factors such as vascular endothelial growth factor A (VEGFA) and protein expression of proangiogenic factor VEGF receptor-2 and fatty acid-binding protein-4 (FABP4) in these cells. Curcumin-stimulated tube formation was associated with an increased expression of VEGFR2 and FABP4. The stimulatory effects of curcumin were inhibited by VEGFR2 (SU5416) and FABP4 (BMS309403) inhibitors. Curcumin also significantly increased both mRNA and protein expression of HLA-G in HTR8/SVneo cells. Curcumin increased mRNA expression of DNMT3A and NOTCH signaling system whereas down-regulated mRNA expression of HSD11β2. Curcumin enhanced hypomethylation of gene promoters against oxidative stress and DNA damage pathway mediators. Curcumin promotes cell growth, migration, and thus angiogenic potential of these cells. Increased expression of HLA-G by curcumin, hitherto unknown, is a novel finding since HLA-G not only favors the immune environment for invasive trophoblasts but also positively modulates angiogenesis.

Comparative single-cell RNA sequencing (scRNA-seq) reveals liver metastasis–specific targets in a patient with small intestinal neuroendocrine cancer

Genomic analysis of a patient's tumor is the cornerstone of precision oncology, but it does not address whether metastases should be treated differently. Here we tested whether comparative single-cell RNA sequencing (scRNA-seq) of a primary small intestinal neuroendocrine tumor to a matched liver metastasis could guide the treatment of a patient's metastatic disease. Following surgery, the patient was put on maintenance treatment with a somatostatin analog. However, the scRNA-seq analysis revealed that the neuroendocrine epithelial cells in the liver metastasis were less differentiated and expressed relatively little SSTR2, the predominant somatostatin receptor. There were also differences in the tumor microenvironments. RNA expression of vascular endothelial growth factors was higher in the primary tumor cells, reflected by an increased number of endothelial cells. Interestingly, vascular expression of the major VEGF receptors was considerably higher in the liver metastasis, indicating that the metastatic vasculature may be primed for expansion and susceptible to treatment with angiogenesis inhibitors. The patient eventually progressed on Sandostatin, and although consideration was given to adding an angiogenesis inhibitor to her regimen, her disease progression involved non-liver metastases that had not been characterized. Although in this specific case comparative scRNA-seq did not alter treatment, its potential to help guide therapy of metastatic disease was clearly demonstrated.

VEGFR1-Targeted Contrast-Enhanced Ultrasound Imaging Quantification of Vasculogenic Mimicry Microcirculation in a Mouse Model of Choroidal Melanoma.

PurposeInvestigate the involvement of vascular endothelial growth factor receptor 1 (VEGFR1) in vasculogenic mimicry (VM) formation in ocular melanoma, as well as whether or not VEGFR1-targeted contrast-enhanced ultrasound (CEUS) can evaluate and quantify VM perfusion and function in the ocular melanoma model.MethodsThe expression of VEGFR1 was examined using immunofluorescence, western blot, and quantitative polymerase chain reaction. VM networks were analyzed with tube formation and periodic acid Schiff staining. Targeted microbubbles (MBs) were constructed and used for targeted CEUS imaging in vivo. Comparisons were made in perfusion parameters of tumors between targeted and non-targeted CEUS imaging.ResultsVEGFR1 was highly expressed, and knockdown of VEGFR1 significantly decreased VM protein expression and disrupted VM formation in MUM-2B melanoma. VEGFR1-targeted MBs specifically bind to MUM-2B cell surfaces. CEUS with VEGFR1-targeted MBs showed significant imaging enhancement throughout the entire perfusion phase compared with CEUS with IgG MBs. VEGFR1-targeted imaging was able to detect a decrease in maximum intensity and mean transit time in VEGFR1 knockdown melanoma compared with control melanoma. The pathological VM patterns were consistent with VEGFR1-targeted CEUS findings.ConclusionsVEGFR1 was responsible for VM network formation and was required for efficient choroidal melanoma tumor growth. This study shows that VEGFR1-targeted CEUS can track VM levels in animal models of ocular melanoma at morphological levels in vivo. This experiment is noninvasive and reproducible and indicates the possibility of real-time in vivo imaging technology for VM evaluation.Translational RelevanceBased on our study results, VEGFR1 could prove to be a promising treatment that targets VM formation in choroidal melanoma. Our findings also suggest the potential use of VEGFR1-targeted CEUS for quantitative monitoring of VM processes at the molecular level in the future.

Effects of low versus standard pressure pneumoperitoneum on renal syndecan-1 shedding and VEGF receptor-2 expression in living-donor nephrectomy: a randomized controlled study

BackgroundLaparoscopic nephrectomy is a preferred technique for living kidney donation. However, positive-pressure pneumoperitoneum may have an unfavorable effect on the remaining kidney and other distant organs due to inflamed vascular endothelium and renal tubular cell injury in response to increased systemic inflammation. Early detection of vascular endothelial and renal tubular response is needed to prevent further kidney injury due to increased intraabdominal pressure induced by pneumoperitoneum. Transperitoneal laparoscopic living donor nephrectomy represented a human model of mild increasing intraabdominal pressure. This study aimed to assess the effect of increased intraabdominal pressure on vascular endothelium and renal tubular cells by comparing the effects of low and standard pressure pneumoperitoneum on vascular endothelial growth factor receptor-2 (VEGFR-2) expression and the shedding of syndecan-1 as the early markers to a systemic inflammation.MethodsWe conducted a prospective randomized study on 44 patients undergoing laparoscopic donor nephrectomy. Subjects were assigned to standard (12 mmHg) or low pressure (8 mmHg) groups. Baseline, intraoperative, and postoperative plasma interleukin-6, syndecan-1, and sVEGFR-2 were quantified by ELISA. Syndecan-1 and VEGFR-2 expression were assessed immunohistochemically in renal cortex tissue. Renal tubule and peritubular capillary ultrastructures were examined using electron microscopy. Perioperative hemodynamic changes, end-tidal CO2, serum creatinine, blood urea nitrogen, and urinary KIM-1 were recorded.ResultsThe low pressure group showed lower intra- and postoperative heart rate, intraoperative plasma IL-6, sVEGFR-2 levels and plasma syndecan-1 than standard pressure group. Proximal tubule syndecan-1 expression was higher in the low pressure group. Proximal-distal tubules and peritubular capillary endothelium VEGFR-2 expression were lower in low pressure group. The low pressure group showed renal tubule and peritubular capillary ultrastructure with intact cell membranes, clear cell boundaries, and intact brush borders, while standard pressure group showed swollen nuclei, tenuous cell membrane, distant boundaries, vacuolizations, and detached brush borders.ConclusionThe low pressure pneumoperitoneum attenuated the inflammatory response and resulted in reduction of syndecan-1 shedding and VEGFR-2 expression as the renal tubular and vascular endothelial proinflammatory markers to injury due to a systemic inflammation in laparoscopic nephrectomy.Trial registrationClinicalTrials.gov NCT:03219398, prospectively registered on July 17th, 2017.

Vascular Abnormalities and the Role of Vascular Endothelial Growth Factor in the Epileptic Brain.

Epilepsy is a chronic neurological disorder generally defined to be caused by excessive neuronal activity. Thus, excessive neuronal activity is the main target of the currently used antiepileptic drugs (AEDs). However, as many as 30% of epileptic patients show drug resistance to currently available AEDs, which suggests that epilepsy should be attributed not only to neuronal cells but also to other brain cells, such as glial cells and vascular cells. Astrocytes, pericytes, and endothelial cells in particular comprise the blood–brain barrier (BBB), which tightly regulates the exchange of substances between the brain parenchyma and the circulating blood. It has been proposed that BBB dysfunction, especially barrier leakage, exacerbates epileptic progression, and conversely, that epileptic seizures induce barrier leakage. Furthermore, several studies have shown that BBB dysfunction is one of the main causes of drug resistance in epilepsy. To better understand the mechanisms that link BBB dysfunction and intractable epilepsy to gain insights for the future development of treatments, we review and discuss the relationships between epilepsy and brain vascular abnormalities, mainly by focusing on vascular malformation, BBB dysfunction, and excessive angiogenesis. Because these abnormalities have been reported to be caused by vascular endothelial growth factor (VEGF) in the ischemic brain, we discuss the possible role of VEGF in vascular abnormalities in the epileptic brain, in which the upregulation of VEGF levels has been reported. Both glial cells and endothelial cells express VEGF receptors (VEGFRs); thus, these cells are likely affected by increases in VEGF during seizures, which in turn could cause vascular abnormalities. In this review, we review the possible role of VEGF in epilepsy and discuss the mechanisms that link vascular abnormalities and intractable epilepsy.

Detection of Mice Colorectal Tumors by Endoluminal Ultrasound Biomicroscopic Images and Quantification of Image Augmented Gray Values Following Injection of VEGFR-2 Targeted Contrast Agent

Ultrasound biomicroscopy (UBM) is a noninvasive imaging technique that can be applied in detecting colonic tumors and, once associated with an ultrasound contrast agent (UCA), can identify the molecular expression of cancer-related biomarkers, such as the vascular endothelial growth factor receptor 2 (VEGFR-2). The present work aimed to detect colonic tumors and quantify augmented gray values of endoluminal UBM (eUBM) images from colonic tumors following the injection of VEGFR-2 targeted UCA (VEGFR2-UCA) into a mouse model of colorectal cancer. A 40 MHz miniprobe catheter inserted through the biopsy channel of a pediatric flexible bronchofiberscope was used to obtain colonoscopic and B-mode eUBM images simultaneously. Seventeen tumor-bearing mice had their colons inspected and six of them were subjected to a VEGFR2-UCA injection to predict VEGFR-2 expression. All animals developed distal colon tumors and eUBM was able to detect all of them and also to characterize the tumors, with 71.4% being in situ lesions and 28.6% being tumors invading the mucosa + muscularis mucosae + submucosa layers, as confirmed by histopathology. After VEGFR2-UCA injection, gray values from the eUBM tumoral images increased significantly (p < 0.01). Tumor sites with increased eUBM image gray values corresponded to areas with increased VEGFR-2 expression, as confirmed by immunohistochemistry. The results confirm eUBM as a powerful noninvasive and real-time tool for detecting colon tumor and its invasiveness and once associated with VEGFR2-UCA may become a tool for the detection of VEGFR-2 expression in colonic tumors.

Expression of VEGFR-2 and Meis1 in the early stage of kidney cancers and its clinical significance.

To evaluate the expression of myeloid ecotropic viral integration site 1 (Meis1) and vascular endothelial growth factor receptor 2 (VEGFR-2) in early-stage kidney cancers and the clinical significance. The cancer tissues and the matched adjacent normal tissues in patients with kidney cancer, who received surgical treatment from April 2005 to September 2018 in the Haikou Hospital Affiliated to Xiangya School of Medicine, Central South University, were collected. The samples included 80 pairs of paraffin specimen, 15 pairs of fresh cancer and the matched adjacent normal tissues from these patients. Real-time PCR and immunohistochemical method were used to detect the expression levels of Meis1 and VEGFR-2 mRNA and protein in kidney tissues and adjacent normal tissues, and the correlation of clinical pathology parameters and the prognosis were analyzed in the patients. The expression levels of Meis1 and VEGFR-2 mRNA and protein in the renal carcinoma tissues were lower than those in the matched adjacent normal tissues (both P<0.01), and the expression levels of Meis1 were positively correlated with that of VEGFR-2 (r=0.681, P<0.01). The analysis of relevant clinical-pathological parameters in the patients showed that: the expression positive rate of Meis1 was significantly related with the pathological type of renal cancer (P<0.01), while the positive rate of Meis1 and VEGFR-2 expression was not related with the gender, age, T stage of patients (all P>0.05), but it was significantly related with the prognosis in the patients (P<0.05). Cox regression analysis showed that: Meis1 was an independent factor for the prognosis of patients (P<0.05). The mRNA and protein expression levels of Meis1 and VEGFR-2 in the early-stage kidney cancer tissues are significantly decreased compared with those in the adjacent normal tissues. Meis1 may be served as a tumor suppressor to affect the occurrence and development of kidney cancer. Therefore, Meis1 may be used as a biomarker to predict the prognosis of patients with kidney cancer.

TIPE regulates VEGFR2 expression and promotes angiogenesis in colorectal cancer.

Background: Metastasis is the leading cause of death in colorectal cancer (CRC) patients. It is regulated mainly by tumor cell angiogenesis, and angiogenesis is caused by the binding of vascular endothelial growth factor (VEGF) to vascular endothelial growth factor receptor 2 (VEGFR2). Tumor necrosis factor-α-induced protein 8 (TNFAIP8, hereto after TIPE) plays an important role in tumorigenesis, development, and prognosis. However, the relationship between TIPE and VEGFR2 in CRC angiogenesis and the mechanism of action remain unknown.Method: In this study, we used quantitative real-time PCR, Western blotting and immunohistochemistry to detect TIPE and VEGFR2 expression in 55 specimens from CRC patients. We also used HCT116 CRC cells and human umbilical vein endothelial cells (HUVECs) for in vitro experiments by stably transducing shTIPE and shRNA control lentivirus into HCT116 cells, detecting VEGFR2 expression after TIPE knockdown and repurposing the culture supernatant as conditioned medium to stimulate angiogenesis of HUVECs. In vivo experiments with chicken chorioallantoic membranes (CAMs) and a nude mouse matrix subcutaneous tumor model were performed to validate the effects of TIPE on angiogenesis. Additionally, we analyzed the expression and phosphorylation levels of PDK1 and blocked PDK1 expression using inhibitors to determine whether TIPE-induced changes in VEGFR2-mediated angiogenesis acted via the PI3K-Akt pathway.Results: We found that TIPE and VEGFR2 are highly expressed in CRC and act as oncogenes. TIPE knockdown also downregulated VEGFR2 expression, which resulted in simultaneous inhibition of cell proliferation, cell migration and angiogenesis. Then, in vivo experiments further demonstrated that TIPE promotes angiogenesis in CRC. Finally, we found that TIPE promotes VEGFR2-mediated angiogenesis by upregulating PDK1 expression and phosphorylation and that blocking PDK1 expression can inhibit this process.Conclusion: TIPE promotes angiogenesis in CRC by regulating the expression of VEGFR2, which may be a target for antiangiogenic cancer therapy.

Role of NDEL1 and VEGF/VEGFR-2 in Mouse Hippocampus After Status Epilepticus.

Nuclear-distribution element-like 1 (NDEL1) is associated with the proliferation and migration of neurons. Vascular endothelial growth factor (VEGF) in combination with VEGF receptor-2 (VEGFR-2) regulates the proliferation and migration of neurons. This study was performed to explore undefined alterations in the expression levels of NDEL1 and VEGF/VEGFR-2 within the hippocampus after status epilepticus (SE). Following the creation of pilocarpine-induced epilepsy models using adolescent male C57BL/6 mice, Western blotting and reverse transcription quantitative polymerase chain reaction were applied to assess the levels of NDEL1, VEGF, and VEGFR-2 expression in whole hippocampi at 1, 2, 3, and 4 weeks post-SE, respectively. Immunofluorescent labeling was also employed to detect the colocalization of NDEL1 and VEGF in the hippocampus. Our results indicated that NDEL1 and VEGF have similar patterns of upregulation throughout the hippocampus. Upregulation of VEGFR-2 occurred only in the early stages, and the expression decreased shortly afterward. NDEL1 and VEGF were coexpressed in the cornu ammonis 3 pyramidal cell, granular, and polymorph layers of the dentate gyrus in the hippocampus. This study revealed that NDEL1, VEGF, and VEGFR-2 may work together and are involved in the pathophysiology in the hippocampus after SE.

Cordyceps militaris fraction inhibits angiogenesis of hepatocellular carcinoma in vitro and in vivo

Background: Cordyceps militaris fraction (CMF) was found to inhibit the proliferation of chronic myeloid leukemia K562 cells, oral squamous carcinoma KB cells, and the metastasis of lung cancer cells. This study focuses on the activity of CMF against angiogenesis of hepatocellular carcinoma (HCC). Objectives: The objective of the study is to research the antiangiogenic activity of CMF in HCC cells and the underlying mechanism in vitro and in vivo. Materials and Methods: Transwell migration and invasion assays were used to measure the effects of CMF on migration and invasion of SMMC-7721 cells and human umbilical vein endothelial cells (HUVECs). Tube formation and rat aortic ring assays were used to assess the antiangiogenic potential of CMF. The antiangiogenic mechanism was detected by immunofluorescence and western blot analysis. The nude mice xenografted with SMMC-7721 cells were used to study the antiangiogenic activity of CMF and its underlying mechanism in vivo. Immunohistochemistry analysis was used to evaluate the effect of CMF on the expression of CD31, and western blot analysis was also performed to detect the expression of vascular endothelial growth factor (VEGF) and other related proteins in tumor tissues. Results: CMF inhibited the migration and invasion of SMMC-7721 cells and HUVECs and suppressed VEGF-induced tube formation of HUVECs and the formation of aortic ring capillaries of rats in a concentration-dependent manner. CMF attenuated the phosphorylation of VEGF receptor 2 (VEGFR2), Akt, and ERK in SMMC-7721 cells and HUVECs. CMF significantly inhibited tumor growth in nude mice xenografted with SMMC-7721 cells. CMF reduced the expression level of CD31, western blot analysis indicated that CMF downregulated the expression of VEGFR2 and attenuated the phosphorylation of Akt and ERK in the tumor tissues, which was consistent with the results obtained from in vitro study. Conclusion: CMF can inhibit the angiogenesis of HCC and the mechanism is associated with suppression of the VEGF/VEGFR2 signaling pathway.

EXPRESS: Gremlin1 blocks vascular endothelial growth factor signalling in the pulmonary microvascular endothelium.

The bone morphogenetic protein (BMP) antagonist gremlin 1 plays a central role in the pathogenesis of hypoxic pulmonary hypertension (HPH). Recently, non‐canonical functions of gremlin 1 have been identified, including specific binding to the vascular endothelial growth factor receptor‐2 (VEGFR2). We tested the hypothesis that gremlin 1 modulates VEGFR2 signaling in the pulmonary microvascular endothelium.We examined the effect of gremlin 1 haploinsufficiency on the expression of VEGF responsive genes and proteins in the hypoxic (10% O2) murine lung in vivo. Using human microvascular endothelial cells in vitro we examined the effect of gremlin 1 on VEGF signaling.Gremlin 1 haploinsufficiency (Grem1+/–) attenuated the hypoxia‐induced increase in gremlin 1 observed in the wild‐type mouse lung. Reduced gremlin 1 expression in hypoxic Grem1+/– mice restored VEGFR2 expression and endothelial nitric oxide synthase (eNOS) expression and activity to normoxic values. Recombinant monomeric gremlin 1 inhibited VEGFA‐induced VEGFR2 activation, downstream signaling, and VEGF‐induced increases in Bcl‐2, cell number, and the anti‐apoptotic effect of VEGFA in vitro.These results show that the monomeric form of gremlin 1 acts as an antagonist of VEGFR2 activation in the pulmonary microvascular endothelium. Given the previous demonstration that inhibition of VEGFR2 causes marked worsening of HPH, our results suggest that increased gremlin 1 in the hypoxic lung, in addition to blocking BMP receptor type‐2 (BMPR2) signaling, contributes importantly to the development of PH by a non‐canonical VEGFR2 blocking activity.

Microvessel density and vascular endothelial growth factor receptors in breast carcinoma under the influence of rapamycin and platelet factor 4

Vascular endothelial growth factor receptors (VEGFRs) are major endothelial growth factor receptors that influence the growth of a tumor. Microvessel density. MVD) is the quantification method of various aspects of tumor vasculature that indicates angiogenic activity. This study aims to analyze the correlation between MVD to the expression of VEGFRs on breast cancer tissue. A total of 60 N-methyl-N-nitrosourea (MNU)-induced breast carcinomas in rats were suppressed by using antiangiogenic drugs. The rats were then sacrificed, and the tumor was fixed in 10% formalin, paraffin embedded, and immunohistochemistry stained using VEGFRs and CD34. One-way ANOVA test showed a significant difference in all markers that have been used (P < 0.05) on MNU-breast tumor treated with rapamycin (M= 90.1664, SD= 7.4487), PF4 (M= 93.7946, SD= 7.1303) and rapamycin + PF4 (M= 93.6990, SD= 1.8432). We obtained a significant reduction of MVD count on breast carcinoma for rapamycin group (M= 25.6786, SD= 9.7075) and rapamycin + PF4 group (M= 30.5250, SD= 13.6928) while PF4 group (M=47.7985, SD=4.8892) showed slightly increase compared to control (M= 45.1875, SD= 4.4786). There was a moderately strong, positive correlation between angiogenic markers; Flt-1 (r= 0.544, n=60, P < 0.005) and Flt-4 (r= 0.555, n= 60, P < 0.005) while Flk-1 (r= 0.797, n= 60, P < 0.005) showed a strong, positive correlation with MVD. MVD was strongly correlated to the VEGFRs expression on breast carcinoma.