• BMB Reports
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• v.51 no.2
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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.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.35 no.2
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• pp.55-65
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• 2009

Purpose: We determined the therapeutic effects of blockade of epidermal growth factor(EGF) and vascular endothelial growth factor(VEGF) receptor tyrosine kinases on the growth of oral squamous cell carcinoma(OSCC) xenografted in athymic nude mice. Experimental Design: We investigated the in vivo antitumor effects of a tyrosine kinase inhibitor for EGFR and VEGFR-2, AEE788 in a mouth floor(orthotopic) tumor model. Nude mice with orthotopic tumors were randomized to receive AEE788, paclitaxel, a combination of AEE788 and paclitaxel, or control. Antitumor mechanisms of AEE788 were determined by immunohistochemical/immunofluorescent and apoptosis assays. Results: Tumors of mice treated with AEE788 demonstrated down-regulation of phosphorylated EGFR, phosphorylated VEGFR and their downstream mediators(pMAPK and pAkt), decreased proliferative index, decreased microvessel density(MVD). As a result, growth of the primary tumor and nodal metastatic potentials were inhibited by AEE788. Conclusion: These data show that EGFR and VEGFR can be molecular targets for the treatment of OSCC.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.36 no.3
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• pp.85-93
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• 2014

Purpose: Nodal metastasis is the main prognostic factor in the patients with oral squamous cell carcinoma (OSCC). We investigated the association between tumor-associated lymphatics and OSCC characteristics. Methods: Thirty-four specimens were used for the immunohistochemical staining with the antibody for vascular endothelial growth factor (VEGF)-C, VEGF-D, VEGF receptor (VEGFR)-3, phosphorylated VEGFR-3, D2-40, and matrix metallproteinases (MMPs). We observed the distribution of the lymphangiogenic factors and quantified the degree of expression. We determined lymphatic vessel density (LVD) and lymphatic vessel dilatation with D2-40 immunostaining. We assessed the association of LVD or lymphatic vessel dilatation with tumor progression or tumor differentiation. Results: OSCC cells expressed lymphangiogenic ligands. Lymphangiogenic receptor, VEGFR-3, was expressed and activated in some tumor cells as well as in tumor-associated endothelial cells. LVD was not associated with tumor size or nodal status, but lymphatic vessel dilatation was higher in tumors with nodal metastasis, and also higher in poorly differentiated tumors. In stromal area of OSCC, MMP-1 and MMP-10 were up-regulated and the basement membrane of tumor-associated endothelial cells was destroyed by these collagenases. Conclusion: In the primary tumors with nodal metastasis, especially in poorly differentiated OSCC, tumor cells invaded the dilated lymphatic vessels via ruptured sites. MMP-1 and MMP-10 are important in the lysis of the glycocalyx inside the tumor-associated lymphatic endothelial cells.

• International Journal of Oncology
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• v.54 no.2
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• pp.753-763
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• 2019

The mutation of isocitrate dehydrogenase (IDH)1 (R132H) and IDH2 (R172K) and the induction of hypoxia in various solid tumors results in alterations in metabolic profiles, including the production of the d- or l-forms of 2-hydroxyglutarate (2HG) from α-ketoglutarate in aerobic metabolism in the tricarboxylic acid (TCA) cycle. However, it is unclear whether the oncometabolite d-2HG increases angiogenesis in endothelial cells. Therefore, in this study, we analyzed the levels of various metabolites, including d-2HG, under hypoxic conditions and in IDH2R172K mutant breast cancer cells by mass spectrometry. We then further evaluated the effects of this metabolite on angiogenesis in breast cancer cells. The results revealed that treatment with d-2HG increased the levels of secreted vascular endothelial growth factor (VEGF) in cancer cells and enhanced endothelial cell proliferation in a concentration-dependent manner. Wound healing and cell migration (examined by Transwell assay) were significantly increased by d-2HG to a level similar to that induced by VEGF. Tube formation was significantly stimulated by d-2HG, and chick chorioallantoic membrane angiogenesis was also enhanced by d-2HG. d-2HG activated VEGF receptor (VEGFR)2 and VEGFR2 downstream signaling, extracellular signal-regulated kinase 1/2, focal adhesion kinase, AKT and matrix metalloproteinase (MMP)2. Taken together, the findings of this study suggested that d-2HG induced angiogenic activity via VEGFR2 signaling and increased MMP2 activity.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.3
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• pp.217-224
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• 2008

Angiogenesis plays an important role in bone development and postnatal bone fracture repair. Vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptors (VEGFRs) have been thought to be primarily involved in promoting angiogenesis. It is well known that VEGF and its receptors have been reported to play an important role in the regulation of the interaction between angiogenesis and osteogenesis during bone repair processes. Dexamethasone, a potent synthetic glucocorticoid, promotes phenotype markers of osteoblast differentiation, such as ALP and osteocalcin. It stimulates in vitro osteogenesis of human bone marrow osteogenic stromal cells. Dexamethasone has been reported to suppress VEGF gene expression in some cells. However, our previous study demonstrated VEGF quantification increased in a time-dependent manner in periosteal-derived osteogenesis under dexamethasone. So, the purpose of this study was to examine the angiogenic phenotypes in cultured human periosteal-derived cells under high-dose dexamethasone. Periosteal-derived cells were cultured using a technique previously described. After passage 3, the periosteal-derived cells were further cultured for 28 days in an osteogenic inductive culture medium containing ascorbic acid, ${\beta}$-glycerophosphate and high-dose dexamethasone, We evaluated the expression of VEGF isoforms, VEGFR-1, VEGFR-2, and neuropilin-1, ALL VEGF isoforms ($VEGF_{121},\;VEGF_{165},\;VEGF_{189}$, and $VEGF_{206}$) expression was observed by RT-PCR analysis. VEGFR-1, VEGFR-2 and neuropilin-1 expression increased up to day 14, particularly during the early stage of mineralization. Our results suggest the involvement of direct VEGFs/VEGFRs system on periosteal-derived cells during early mineralization phase under high-dose of dexamethasone. These also suggest that VEGF might act as an autocrine growth molecule during osteoblastic differentiation of cultured human periosteal-derived cells.

• Bulletin of the Korean Chemical Society
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• v.27 no.9
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• pp.1285-1286
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• 2006

• Oncology Reports
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• v.43 no.2
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• pp.625-634
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• 2020

While exploring new angiogenesis inhibitors from microbial metabolites, we recently isolated ahpatinins C, E, and G from a soil-derived Streptomyces sp. 15JA150. Ahpatinins C, E and G are known to have pepsin and renin inhibitory activities; however, their antiangiogenic activities and underlying molecular mechanisms have not been fully elucidated. In the present study, the antiangiogenic properties of ahpatinins C, E and G were investigated. The results revealed that the natural compounds significantly inhibited the vascular endothelial growth factor (VEGF)-induced proliferation, invasion, adhesion, and tube formation of human umbilical vein endothelial cells (HUVECs) without exhibiting any cytotoxicity. It was also revealed that ahpatinin E effectively suppressed the neovascularization of the chorioallantoic membranes in growing chick embryos. Notably, ahpatinins C, E, and G led to the downregulation of VEGF-induced activation of VEGF receptor 2 (VEGFR2) and its downstream signaling mediators, including AKT, ERK1/2, JNK, p38, and NF-κB, in HUVECs. Moreover, they reduced the expression of matrix metalloproteinase (MMP)-2 and MMP-9 in the HUVECs following stimulation with VEGF. Furthermore, ahpatinins C, E, and G reduced the tumor cell-induced invasion and tube forming abilities of HUVECs, as well as the expression of VEGF, by suppressing hypoxia-inducible factor-1α (HIF-1α) activity in U87MG glioblastoma cells. Collectively, the present findings indicated that ahpatinins C, E, and G may be used in anticancer therapy by targeting tumor angiogenesis through the inhibition of both VEGFR2 and HIF-1α pathways.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.7
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• pp.3053-3060
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• 2016

Gastric cancer is generally associated with poor survival rates and accounts for a remarkable proportion of global cancer mortality. The prevalence of gastric carcinoma varies in different regions of world and across teh various ethnic groups. On the basis of pathological assessment, gastric cancer can be categorized as intestinal and diffuse carcinomas. The etiology is diverse, including chemical carcinogen exposure, and high salt intake Helicobacter pylori also plays a vital role in the pathogenesis of certain gastric carcinomas. The development of gastric cancer involves various alterations in mRNAs, genes (GOLPH3, MTA2) and proteins (Coronins). miRNAs, Hsa-mir-135b, MiR-21, miR-106b, miR-17, miR-18a, MiR-21, miR-106b, miR-17, miR-18a and MiRNA-375, miRNA-195-5p are the latest diagnostic biomarkers which can facilitate the early diagnosis of gastric carcinomas. Recent development in the treatment strategies for gastric carcinoma include the introduction of monoclonal antibodies, TKI inhibitors, inhibitors of PDGFR ${\beta}$, VEGFR-1, VEGFR-2, Anti-EGFR and anti-HER2 agents which can be applied along with conventional therapies.

• Korean Journal of Clinical Laboratory Science
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• v.50 no.4
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• pp.457-461
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• 2018

Corpus luteum (CL) is a transient endocrinal tissue that undergoes repeated formation and regression during the estrous cycle. In this study, we hypothesized that the functional and structural mechanism of angiogenesis is similar between CL and tumor formation. First, we measured mRNA and protein expression of angiogenic receptors (vascular endothelial growth factor receptor-2, VEGFR2; Tie 2) in the early, middle, and late phase CL tissues during the estrous cycle. Ral-interacting protein of 76 kDa (RLIP76) and H-ras mRNA and protein were also expressed in the CL tissues. VEGFR2 and Tie 2 mRNA and protein were expressed in the early and middle phase CLs and decreased in the late phase. H-ras mRNA and protein were expressed in the early and middle phase CLs, but not in the late phase. RLIP76 mRNA was expressed in all phase CLs, and the protein expression was highest in early phase CLs. We suggest that RLIP76 and H-ras, an oncogenic gene, regulate the function of the CL during the estrous cycle, and the proteins will play an important role in the angiogenic mechanism of the CL.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.35 no.2
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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.