• Bulletin of the Korean Chemical Society
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• 제30권9호
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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.

• 통합자연과학논문집
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• 제10권3호
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• pp.141-147
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• 2017

Vascular endothelial growth factor (VEGF) is an important signaling protein involved in angiogenesis, which is the formation of new blood vessels from pre-existing vessels. Consequently, blocking of the vascular endothelial growth factor receptor (VEGFR-2) by small molecule inhibitors leads to the inhibition of cancer induced angiogenesis. In this study, we performed a two dimensional quantitative structure activity relationship (2D-QSAR) study of 38 N-Phenyl-N'-{4-(4-quinolyloxy) phenyl} urea derivatives as VEGFR-2 inhibitors based on hologram quantitative structure-activity (HQSAR). The model developed showed reasonable $q^2=0.521$ and $r^2=0.932$ values indicating good predictive ability and reliability. The atomic contribution map analysis of most active compound (compound 7) indicates that hydrogen and oxygen atoms in the side chain of ring A and oxygen atom in side chain of ring C contributes positively to the activity of the compounds. The HQSAR model developed and the atomic contribution map can serve as a guideline in designing new compounds for VEGFR-2 inhibition.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제27권2호
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• pp.110-122
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• 2005

Adenoid cystic carcinoma (ACC) of salivary glands has a protracted clinical course with perineural invasion, delayed onset of hematogenous metastasis, and poor responses to classical cytotoxic chemotherapic agents. Most deaths from salivary ACC are caused by lung metastases that are resistant to conventional therapy. Therefore, knowledge of cellular properties and tumor-host interactions that influence the dissemination of metastatic cells is important for the design of more effective therapy of salivary cancer. I determined in vitro expression of epidermal growth factor receptor (EGFR) and its downstream effectors and vascular endothelial growth factor receptor (VEGFR)-2 on a human salivary ACC cell line (ACC2). I also evaluated the expression of EGF and VEGF signaling molecules and metastasis-related proteins on human salivary ACC cells orthotopically growing in nude mice. In Western blot and immunohistochemical analyses, EGFR and VEGFR-2 were presented and phosphorylated in ACC2 cells. In human parotid cancer xenografts in nude mice, EGF and VEGF signaling molecules, IL-8, and MMP-9 were expressed at markedly higher levels than in normal parotid tissues. Moreover, tumor-associated endothelial cells of this orthotopic parotid tumor expressed phosphorylated VEGFR-2 and phosphorylated Akt, which is a cell-survival protein. These data show that those biomarkers can be molecular targets for therapy of salivary ACC, which has a propensity for delayed lung metastasis.

• 한국식품과학회지
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• 제51권2호
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• pp.141-146
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• 2019

본 연구에서는 꽃송이버섯 소수성 추출물(SCF4)의 항혈관신생활성을 혈관내피세포인 HUVECs을 사용하여 확인하였다. 그 결과, SCF4는 세포 독성을 나타내지 않는 $5-25{\mu}g/mL$의 농도에서 VEGF에 의해 유도된 혈관내피세포 증식을 유의적으로 감소시켰을 뿐만 아니라, 혈관내피세포 침윤성과 관 형성 능력을 농도의 존적으로 감소시켜 in vitro 혈관신생을 효과적으로 저해함을 확인하였다. 또한, SCF4는 독성을 나타내지 않고 CAM의 혈관신생을 저해함으로써, in vivo 혈관신생을 효과적으로 저해함을 확인하였다. 마지막으로 SCF4가 혈관신생을 유도하는 주요 신호전달 경로인 VEGFR2, AKT 및 ERK1/2의 전체 단백질 발현 수준의 변화없이 인산화를 저해함을 확인하였다. 따라서, 본 연구는 꽃송이버섯 소수성 추출물이 혈관신생 저해활성을 나타내고 이러한 현상은 VEGFR2 신호전달경로의 억제를 통해 진행됨을 입증하여, 혈관신생 관련 질환 예방 및 치료를 위한 천연물 소재로서의 적용 가능성을 새롭게 제시하였다.

• Clinical and Experimental Pediatrics
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• 제59권1호
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• pp.8-15
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• 2016

Purpose: Nephrogenesis is normally accompanied by a tightly regulated and efficient vascularization. We investigated the effect of angiotensin II inhibition on angiogenesis in the developing rat kidney. Methods: Newborn rat pups were treated with enalapril (30 mg/kg/day) or vehicle (control) for 7 days after birth. Renal histological changes were checked using Hematoxylin & Eosin staining. We also investigated the intrarenal expression of vascular endothelial growth factor (VEGF)-A, VEGF receptor 1 (VEGFR1), VEGFR2, platelet-derived growth factor (PDGF)-B, and PDGF receptor-${\beta}$ with Western blotting and immunohistochemical staining at postnatal day 8. Expression of the endothelial cell marker CD31 was examined to determine glomerular and peritubular capillary density. Results: Enalapril-treated rat kidneys showed disrupted tubules and vessels when compared with the control rat kidneys. In the enalapril-treated group, intrarenal VEGF-A protein expression was significantly higher, whereas VEGFR1 protein expression was lower than that in the control group (P<0.05). The expression of VEGFR2, PDGF-B, and PDGF receptor-${\beta}$ was not different between the 2 groups. The increased capillary CD31 expression on the western blots of enalapril-treated rat kidneys indicated that the total endothelial cell protein level was increased, while the cortical capillary density, assessed using CD31 immunohistochemical staining, was decreased. Conclusion: Impaired VEGF-VEGFR signaling and altered capillary repair may play a role in the deterioration of the kidney vasculature after blocking of angiotensin II during renal development.

• Biomolecules & Therapeutics
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• 제31권4호
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• pp.456-465
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• 2023

Cervical tumors represent a prevalent form of cancer affecting women worldwide; current treatment options involve surgery, radiotherapy, and chemotherapy. Angiogenesis, the process of new blood vessel formation, is a crucial factor in cervical tumor growth. The molecular mechanisms underlying the effects of the liver kinase B1 (LKB1/STK11) tumor suppressor protein on tumor angiogenesis have not been elucidated. Therefore, we investigated the role of LKB1 in cervical tumor angiogenesis both in vitro and in vivo in this study. Our results demonstrated that LKB1 inhibited cervical tumor angiogenesis by suppressing the expression of angiogenesis-related factors such as vascular endothelial growth factor (VEGF) and hypoxia inducible factor-1α. LKB1 directly affected both carcinoma and vascular endothelial cells, resulting in a significant reduction in tumor growth and angiogenesis. Furthermore, LKB1 was found to bind to VEGF receptor 2 (VEGFR-2) and target the VEGFR-2-mediated protein kinase B/mechanistic target of rapamycin signaling pathway in endothelial cells, thereby reducing cervical tumor growth and angiogenesis. Our study provides new insights into the molecular mechanisms underlying the anti-tumor and anti-angiogenic effects of LKB1 in cervical cancer. These findings will help develop new therapeutic strategies for cervical cancer.

• BMB Reports
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• 제51권2호
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• pp.73-78
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• 2018

Vascular endothelial growth factor and its receptor (VEGF-VEGFR) system play a critical role in the regulation of angiogenesis and lymphangiogenesis in vertebrates. Each of the VEGF has specific receptors, which it activates by binding to the extracellular domain of the receptors, and, thus, regulates the angiogenic balance in the early embryonic and adult stages. However, de-regulation of the VEGF-VEGFR implicates directly in various diseases, particularly cancer. Moreover, tumor growth needs a dedicated blood supply to provide oxygen and other essential nutrients. Tumor metastasis requires blood vessels to carry tumors to distant sites, where they can implant and begin the growth of secondary tumors. Thus, investigation of signaling systems related to the human disease, such as VEGF-VEGFR, will facilitate the development of treatments for such illnesses.

• Genomics & Informatics
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• 제19권1호
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• pp.6.1-6.10
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• 2021

Vascular endothelial growth factor (VEGF) is expressed at elevated levels by most cancer cells, which can stimulate vascular endothelial cell growth, survival, proliferation as well as trigger angiogenesis modulated by VEGF and VEGFR (a tyrosine kinase receptor) signaling. The angiogenic effects of the VEGF family are thought to be primarily mediated through the interaction of VEGF with VEGFR-2. Targeting this signaling molecule and its receptor is a novel approach for blocking angiogenesis. In recent years virtual high throughput screening has emerged as a widely accepted powerful technique in the identification of novel and diverse leads. The high resolution X-ray structure of VEGF has paved the way to introduce new small molecular inhibitors by structure-based virtual screening. In this study using different alkaloid molecules as potential novel inhibitors of VEGF, we proposed three alkaloid candidates for inhibiting VEGF and VEGFR mediated angiogenesis. As these three alkaloid compounds exhibited high scoring functions, which also highlights their high binding ability, it is evident that these alkaloids can be taken to further drug development pipelines for use as novel lead compounds to design new and effective drugs against cancer.

• Biomolecules & Therapeutics
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• 제27권5호
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• pp.474-483
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• 2019

Vascular endothelial growth factor (VEGF) plays a pivotal role in pathologic ocular neovascularization and vascular leakage via activation of VEGF receptor 2 (VEGFR2). This study was undertaken to evaluate the therapeutic mechanisms and effects of the tetrapeptide Arg-Leu-Tyr-Glu (RLYE), a VEGFR2 inhibitor, in the development of vascular permeability and choroidal neovascularization (CNV). In cultured human retinal microvascular endothelial cells (HRMECs), treatment with RLYE blocked VEGF-A-induced phosphorylation of VEGFR2, Akt, ERK, and endothelial nitric oxide synthase (eNOS), leading to suppression of VEGF-A-mediated hyper-production of NO. Treatment with RLYE also inhibited VEGF-A-stimulated angiogenic processes (migration, proliferation, and tube formation) and the hyperpermeability of HRMECs, in addition to attenuating VEGF-A-induced angiogenesis and vascular permeability in mice. The anti-vascular permeability activity of RLYE was correlated with enhanced stability and positioning of the junction proteins VE-cadherin, ${\beta}$-catenin, claudin-5, and ZO-1, critical components of the cortical actin ring structure and retinal endothelial barrier, at the boundary between HRMECs stimulated with VEGF-A. Furthermore, intravitreally injected RLYE bound to retinal microvascular endothelium and inhibited laser-induced CNV in mice. These findings suggest that RLYE has potential as a therapeutic drug for the treatment of CNV by preventing VEGFR2-mediated vascular leakage and angiogenesis.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제35권2호
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• pp.66-73
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• 2009

Tumor angiogenesis is a process leading to formation of blood vessels within tumors and is crucial for maintaining a supply of oxygen and nutrients to support tumor growth and metastasis. Vascular endothelial growth factor(VEGF) plays a key role in tumor angiogenesis including induction of endothelial cell proliferation, migration, survival and capillary tube formation. VEGF binds to two distinct receptors on endothelial cells. VEGFR-2 is considered to be the dominant signaling receptor for endothelial cell permeability, proliferation, and differentiation. Bevacizumab(Avastin, Genetech, USA) is a monoclonal antibody against vascular endothelial growth factor. It is used in the treatment of cancer, where it inhibits tumor growth by blocking the formation of new blood vessels. The goal of this study is to identify the anti-tumor effect of Bevacizumab(Avastin) for oral squamous cell carcinoma cell lines. Human squamous cell carcinoma cell line(HN4) was used in this study. We examined the sensitivity of HN4 cell line to Bevacizumab(Avastin) by using in vitro proliferation assays. The results were as follows. 1. In the result of MTT assay according to concentration of Bevacizumab(Avastin), antiproliferative effect for oral squamous cell carcinoma cell lines was observed. 2. The growth curve of cell line showed the gradual growth inhibition of oral squamous cell carcinoma cell lines after exposure of Bevacizumab(Avastin). 3. In the apoptotic index, groups inoculated Bevacizumab(Avastin) were higher than control groups. 4. In condition of serum starvation, VEGFR-2 did not show any detectable autophosphorylation, whereas the addition of VEGF activated the receptor. Suppression of phosphorylated VEGFR-2 and phosphorylated MAPK was observed following treatment with Bevacizumab(Avastin) in a dose-dependent manner. 5. In TEM view, dispersed nuclear membrane, scattered many cytoplasmic vacuoles and localized chromosomal margination after Bevacizumab(Avastin) treatment were observed. These findings suggest that Bevacizumab(Avastin) has the potential to inhibit MAPK pathway in proliferation of oral squamous cell carcinoma cell lines via inhibition of VEGF-dependent tumor growth.