• BMB Reports
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• v.39 no.5
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• pp.469-478
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• 2006

Vascular endothelial growth factor (VEGF)-A, a major regulator for angiogenesis, binds and activates two tyrosine kinase receptors, VEGFR1 (Flt-1) and VEGFR2 (KDR/Flk-1). These receptors regulate physiological as well as pathological angiogenesis. VEGFR2 has strong tyrosine kinase activity, and transduces the major signals for angiogenesis. However, unlike other representative tyrosine kinase receptors which use the Ras pathway, VEGFR2 mostly uses the Phospholipase-$C{\gamma}$-Protein kinase-C pathway to activate MAP-kinase and DNA synthesis. VEGFR2 is a direct signal transducer for pathological angiogenesis including cancer and diabetic retinopathy, thus, VEGFR2 itself and the signaling appear to be critical targets for the suppression of these diseases. VEGFR1 plays dual role, a negative role in angiogenesis in the embryo most likely by trapping VEGF-A, and a positive role in adulthood in a tyrosine kinase-dependent manner. VEGFR1 is expressed not only in endothelial cells but also in macrophage-lineage cells, and promotes tumor growth, metastasis, and inflammation. Furthermore, a soluble form of VEGFR1 was found to be present at abnormally high levels in the serum of preeclampsia patients, and induces proteinurea and renal dysfunction. Therefore, VEGFR1 is also an important target in the treatment of human diseases. Recently, the VEGFR2-specific ligand VEGF-E (Orf-VEGF) was extensively characterized. Interestingly, the activation of VEGFR2 via VEGF-E in vivo results in a strong angiogenic response in mice with minor side effects such as inflammation compared with VEGF-A, suggesting VEGF-E to be a novel material for pro-angiogenic therapy.

• Korean Journal of Biological Psychiatry
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• v.14 no.4
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• pp.232-240
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• 2007

Objectives : Vascular endothelial growth factor(VEGF), one of potent cytokines, and its receptors were related with various biological functions and pathological conditions. The purpose of this study was to investigate the changes of serum level of free VEGF, soluble VEGFR-1, and soluble VEGFR-2 after treatment with atypical antipsychotic drug in schizophrenia. Method : The schizophrenic patients were diagnosed with DSM-IV and were prospectively followed up for 4 and 8 weeks. Thirteen schizophrenic patients were evaluated their clinical assessment with serum levels of free VEGF, sVEGFR-1, sVEGFR-2, and positive and negative symptom scale(PANSS) at baseline, 4 weeks, and 8 weeks after treatment with atypical antipsychotic drug. Thirteen normal control subjects were recruited and matched with the patient group by age and sex. Result : The serum level of free VEGF($295.2{\pm}43.7$pg/ml)and sVEGFR-2($8259{\pm}336.7$) at baseline(before treatment) in schizophrenic patients were not significantly different, compared with the control group($199.0{\pm}28.8$ and $8481{\pm}371.9$) respectively. However, the serum level of sVEGFR-1($86.2{\pm}10.3$, p<0.05) was significantly increased in the schizophrenic patients compared with the control group($59.0{\pm}6.4$). After treatment with antipsychotic drug, the serum levels of free VEGF at 4 weeks($338.9{\pm}56.5$) and 8 weeks($309.5{\pm}58.7$) were not significantly, different compared with baseline. But the serum levels of sVEGFR-1 was significantly decreased at 8 weeks ($57.3{\pm}6.3$, p<0.05) after antipsychotic drug treatment. The serum levels of sVEGFR-2 were decreased at 4 weeks ($7761{\pm}403.0$, p<0.05) and 8 weeks($7435{\pm}333.5$, p<0.05) compared with baseline. Conclusion : The decreased serum level of sVEGFR-1 and sVEGFR-2 might be affected by dopaminergic system which was influenced by antipsychotic drug.

• Journal of Life Science
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• v.34 no.2
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• pp.128-137
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• 2024

This review discusses the pivotal role of vascular endothelial growth factors (VEGF) in angiogenesis and lymphangiogenesis, vital processes influencing vascular permeability, endothelial cell recruitment, and the maintenance of tumor-associated blood and lymphatic vessels. VEGF exerts its effects through tyrosine-kinase receptors, VEGFR-1, VEGFR-2, and VEGFR-3. This VEGF-VEGFR system is central not only to cancer but also to diseases arising from abnormal blood vessel and lymphatic vessel formation. In the context of cancer, VEGF and its receptors are essential for the development of tumor-associated vessels, making them attractive targets for therapeutic intervention. Various approaches, such as anti-VEGF antibodies, receptor antagonists, and VEGF receptor function inhibitors, are being explored to interfere with tumor growth. However, the clinical efficacy of anti-angiogenic agents remains uncertain and necessitates further refinement. The article also highlights the physiological role of VEGFs, emphasizing their involvement in endothelial cell functions, survival, and vascular permeability. The identification of five distinct VEGFs in humans (VEGF-A, VEGF-B, VEGF-C, VEGF-D, and PLGF) is discussed, along with the classification of VEGFRs as typical receptor tyrosine kinases with distinct signaling systems. The family includes VEGFR-1 and VEGFR-2, crucial in tumor biology and angiogenesis, and VEGFR-3, specifically involved in lymphangiogenesis. Overall, this review has provided a comprehensive overview of VEGF and VEGFR, detailing their roles in various diseases, including cancer. This is expected to further facilitate the utilization of VEGF and VEGFR as therapeutic targets.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.4
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• pp.2217-2221
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• 2016

Vascular endothelial growth factor 2 (VEGFR2) was initially identified as a receptor of VEGF on endothelial cells with a role in regulating angiogenesis during organism development and tumorigenesis. Previously, in cancer tissue, VEGFR2 has been reported to be expressed in endothelial cells. In our research, we found that VEGFR2 was expressed not only in endothelial cells but also cancer cells in head and neck squamous cell carcinomas (HNSCCs). Knockdown of VEGFR2 in Hep2 cells could arrest the cell cycle in G0/G1, leading to a decrease in proliferation. We also present evidence that MAPK/ERK signal pathways and expression of CDK1 downstream of VEGFR2 might regulate proliferation and cell cycle arrest. Furthermore, we discovered that down-regulate VEGRF2 in Hep2 cells could significantly affect the invasion ability. Taken together, our data suggest that VEGFR2 might regulate proliferation and invasion in HNSCC cancer cells in vivo.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.1
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• pp.1-9
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• 2011

Purpose: Tumor associated angiogenesis and/or lymphangiogenesis are known to be linked by VEGFR signaling pathways. These processes are regulated by several growth factors including VEGFR-2, VEGFR-3. E7080 is an orally active inhibitor of multiple tyrosine kinases including VEGFR-2, 3. Therefore, it was proposed that E7080 may inhibit angiogenesis and lymphangiogenesis. The aim of this study was to determine the effect of E7080 in a nude mouse model of OSCC. Methods: KB cells were xenografted into the submucosal tissue of the mouth floor of athymic mice. Seven days after the xenograft, the mice were randomized into 2 groups. E7080 were administered orally to the experimental group once per day. The mice were sacrificed 3 weeks after the treatment. The tumors were examined histopathologically. Immunohistochemical assays with anti- VEGF-C, VEGFR-2, VEGFR-3, phosphorylated VEGFR-2/3 (pVEGFR-2/3), and D2-40 antibodies were then performed. Results: The transplantation of human OSCC tumor cells into the mouth floor resulted in the formation of orthotopic tumors. The experimental (E7080 treatment) group showed a slowly increased tumor volume. Moreover, immunohistochemical staining demonstrated higher levels of VEGF-C, VEGFR-2, VEGFR-3, pVEGFR-2/3 and D2-40 expression in the control group than in the experimental group. Conclusion: These results suggest that E7080 may provide therapeutic benefits in OSCC.

• BMB Reports
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• v.57 no.5
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• pp.244-249
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• 2024

Many types of cancer are associated with excessive angiogenesis. Anti-angiogenic treatment is an effective strategy for treating solid cancers. This study aimed to demonstrate the inhibitory effects of (E)-2-methoxy-4-(3-(4-methoxyphenyl) prop-1-en-1-yl) phenol (MMPP) in VEGFA-induced angiogenesis. The results indicated that MMPP effectively suppressed various angiogenic processes, such as cell migration, invasion, tube formation, and sprouting of new vessels in human umbilical vein endothelial cells (HUVECs) and mouse aortic ring. The inhibitory mechanism of MMPP on angiogenesis involves targeting VEGFR2. MMPP showed high binding affinity for the VEGFR2 ATP-binding domain. Additionally, MMPP improved VEGFR2 thermal stability and inhibited VEGFR2 kinase activity, suppressing the downstream VEGFR2/AKT/ERK pathway. MMPP attenuated the activation and nuclear translocation of NF-κB, and it downregulated NF-κB target genes such as VEGFA, VEGFR2, MMP2, and MMP9. Furthermore, conditioned medium from MMPP-treated breast cancer cells effectively inhibited angiogenesis in endothelial cells. These results suggested that MMPP had great promise as a novel VEGFR2 inhibitor with potent anti-angiogenic properties for cancer treatment via VEGFR2/AKT/ERK/NF-κB signaling pathway.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.1
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• pp.11-19
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• 2007

This study was to evaluate the expression of vascular endothelial growth factor receptors (VEGFRs) in tumor and stromal cells of tougue squamous cell carcinoma (SCC). We also wanted to characterize the differences, from the angiogenic aspect, between cancer-associated stromal cells and non-malignant stromal cells. Paraffin-embedded tumor specimens from eleven patients with tongue SCCs were studied. Immunohistochemical staining for VEGFR-1,-2, and -3 was performed on the tumor cells, stromal fibroblasts and tumor-associated macrophages of the specimens. The expression of all 3 receptors was detected in the tumor cells themselves of the biopsy specimens. All 3 receptors were also expressed on stromal cells, except that VEGFR-2 was not expressed in stromal fibroblasts. In radical excision specimens, the staining intensity for VEGFR-1, -2 in the tumor cells and VEGFR-1,-3 in the tumor-associated macrophages was significantly lower than that in the biopsy specimens (P < 0.05). By using the general marker of fibroblast and macrophage, 5B5 and CD68, respectively, we performed double immunofluorescence staining for 5B5 and each VEGFR in the stromal fibroblasts and for CD68 and each VEGFR in the tumor-associated macrophages of the radical excision specimens. We used 4 cases of fibroma and 4 cases of chronic inflammation tissue as the controls. It was found that only each marker was expressed in the control group, however, 5B5/VEGFR-1 and 5B5/VEGFR-3 in the stromal fibroblasts, and CD68/VEGFR-1 and CD68/VEGFR-3 in the tumor-associated macrophages were double stained in the radical excision specimens. Although our study used small number of specimens, the results of our study showed that in tongue SCC, in association with the angiogenesis, the stromal cells showed the activated phenotype and this was different from the nonmalignant stromal cells.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.1
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• pp.1-8
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• 2010

Background and Purpose: Vascular endothelial growth factor (VEGF)-C and VEGF receptor (VEGFR)-3 are involved in tumor lymphangiogenesis. Oral mucosal squamous cell carcinoma (OMSCC) preferentially metastasizes to cervical lymph nodes, so we investigated the expression and distribution of VEGFR-3 signaling proteins in OMSCC. Materials and Methods: Tissue samples of 18 OMSCC, 10 oral mucosal leukoplakia, and 3 normal oral mucosa were evaluated for expression of VEGF-C, VEGF-D, and VEGFR-3 by immunohistochemical staining. The presence of lymphatic vessels was determined using D2-40 staining, by which we also measured lymphatic vessel density (LVD). Results: 72% (13/18) and 56% (10/18) of tissue samples showed VEGF-C and VEGF-D immunopositivity in tumor cells and tumor-associated endothelial cells. VEGFR-3 was also expressed in most of OMSCC, which was up-regulated when compared with normal mucosa or with leukoplakia. Furthermore, LVD was higher in OMSCC than in leukoplakia. Conclusion: Taken together, our results suggest that autocrine activation of lymphatic endothelial cell via VEGFR-3 by VEGF-C and/or VEGF-D could be involved in progression of OMSCC. Therefore, VEGF-C/VEGFR-3 signaling pathway can be a molecular target for anti-metastatic therapy in OMSCC.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.4
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• pp.2443-2446
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• 2013

Published data have shown that the levels of vascular endothelial growth factor (VEGF) and soluble VEGF receptor-1 (sVEGFR-1) in plasma and pleural effusion might be usefulness for lung cancer diagnosis. Here, we performed a prospective study to investigate the utility of VEGF and sVEGFR-1 in bronchoalveolar lavage fluid (BALF) for differential diagnosis of primary lung cancer. A total of 56 patients with solitary pulmonary massed by chest radiograph or CT screening were enrolled in this study. BALF and plasma samples were obtained from all patients and analyzed for VEGF and sVEGFR-1 using a commercially available sandwich ELISA kit. The results showed that the levels of VEGF in BALF were significantly higher in patients with a malignant pulmonary mass compared with patients with a benign mass (P < 0.001). However, no significant difference of sVEGFR-1 in BALF was found between malignant and non-malignant groups (P = 0.43). With a cut-off value of 214 pg/ml, VEGF showed a sensitivity and specificity of 81.8% and 84.2%, respectively, in predicting the malignant nature of a solitary pulmonary mass. Our study suggests that VEGF is significantly increased in BALF among patients with lung cancer than in benign diseases. Measurement of VEGF in BALF might be helpful for differential diagnosis of primary lung cancer.

• Bulletin of the Korean Chemical Society
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• v.30 no.9
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• pp.2083-2086
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• 2009

Human vascular endothelial growth factor receptor 2 (hVEGFR2) is an important signaling protein involved in angiogenesis and attractive drug target in cancer therapy. It has been reported that flavonols, a class of flavonoids, have anti-angiogenic activity in various cancer cell lines. We performed receptor-oriented pharmacophore based in silico screening for identification of hVEGFR2 inhibitors from flavonol database. By comparing with three X-ray complex structures of hVEGFR2 and its inhibitors, we evaluated the specific interactions between inhibitors and receptors and determined a single pharmacophore map. This map consisted of four features, a hydrogen bonding acceptor (HBA) on Cys917, two hydrogen bonding donors on Glu917 (HBD1) and Glu883 (HBD2), and one hydrophobic interaction (Lipo) with Val846, Ala864, Val897, Val914 and Phe1045 of hVEGFR2. Using this map, we searched a flavonol database including 9 typical flavonols and proposed that five flavonols, kaempferol, quercetin, fisetin, morin, and rhamnetin can be potent inhibitors of hVEGFR2. 3-OH of C-ring and 4’-OH of B-ring of flavonols are the essential features for hVEGFR2 inhibition. This study will be helpful for understanding the mechanism of inhibition of hVEGFR2 by natural products.