• Molecules and Cells
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• 제45권11호
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• pp.789-791
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• 2022

Targeting fibroblast growth factor receptors (FGFRs) has been slow compared to other targeted cancer therapies for receptor tyrosine kinases, such as epidermal growth factor receptors. The low efficacy and variable response have limited the growth of FGFR inhibitors in clinical use. Nevertheless, recent systematic and genomic approaches have identified the biological conditions for effectively targeting FGFRs and can accelerate the development of targeted drugs. Under clinical and preclinical trials, the inhibitors started fast growing furious races to target FGFRs. Finally, FGFRs will be more actionable and targetable with more precise and effective drugs at the end of the race, passing the finish line.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제28권6호
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• pp.549-558
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• 2006

During distraction osteogenesis, the angiogenic activity is crucial factor in the new bone formation. The aim of this study was to detect the autocrine growth activity in the cellular components of the distracted periosteum with observation of the expression of vascular endothelial growth factor (VEGF) and its receptors following the mandibular distraction osteogenesis. Unilateral mandibular distraction (0.5 mm twice per day for 10 days) was performed in six mongrel dogs. Two animals were sacrificed at 7, 14, and 28 days after completion of distraction, respectively. The distracted lingual periosteum was harvested and processed for immunohistochemical examinations. After then, we observed the expression of VEGF, Flt-1 (VEGFR-1), and Flk-1 (VEGFR-2) in the osteoblasts and immature mesenchymal cells of the distracted periosteum. At 7 days after distraction, the expression of VEGF and its receptors were significantly increased in the cellular components of the distracted periosteum. Up to 14 days following distraction, the increased expressions were maintained in the osteoblastic cells. At 28 days after distraction, the expression of VEGF and its receptors decreased, but VEGF was still expressed weak or moderate in the osteoblastic cells of distracted periosteum. The expression pattern of VEGF and its receptors shown here suggested that VEGF play an important role in the osteogenesis, and these osteoblastic cell-derived VEGF might act as autocrine growth factor during distraction osteogenesis. In the other word, the cellular components in the distracted periosteum, such as osteoblasts and immature mesenchymal cells, might have autocrine growth activity during distraction osteogenesis.

• Journal of Periodontal and Implant Science
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• 제25권3호
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• pp.518-528
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• 1995

The immunohistochemical study has been performed on the distribution of receptors for various growth factors in the newly forming granulation tissues following the guided tissue regeneration procedures. Two specimens from 2 different patients were collected from the newly forming granulation tissues at 2 weeks following GTR procedures using Gore-tex menbrane and rubber dam, respectively. For immunohistochemical localization of each recptor, anti-platelet-derived growth factor $receptor-{\alpha}$, anti-platelet-derived growth factor $receptor-{\beta}$. anti-insulin-like growth factor receptor, anti-basic fibroblast growth factor receptor, anti-transforming growth $factor-{\beta}$ receptor and anti-fibronectin receptor were incubated onto the specimens as primary antibodies. After the reaction, FITC-conjugated second antibodies have been applied. When the total numbers of immunoreactive cells and the true positive cells were counted, there were high variability among receptors tested in the present study. The mean number of immunoreactive cells were highest in the case for anti-IFG-1 receptor. However the number of true positive cells were highest in the case for $TGF-{\beta}$ receptor. The present investigation indicated that the receptor for $TGF-{\beta}$ were stongly expressed in the newly forming granulation tissues following the guided tissue regeneration therapy.

• BMB Reports
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• 제44권3호
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• pp.182-186
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• 2011

Exogenous stimuli such as nerve growth factor (NGF) exert their effects on neurite outgrowth via Trk neurotrophin receptors. TrkA receptors are known to be ubiquitinated via proteasome inhibition in the presence of NGF. However, the effect of proteasome inhibition on neurite outgrowth has not been studied extensively. To clarify these issues, we investigated signaling events in PC12 cells treated with NGF and the proteasome inhibitor MG132. We found that MG132 facilitated NGF-induced neurite outgrowth and potentiated the phosphorylation of the extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) and phosphatidylinositol-3-kinase (PI3K)/AKT pathways and TrkA receptors. MG132 stimulated internalization of surface TrkA receptor and stabilized intracellular TrkA receptor, and the $Ub^{K63}$ chain was found to be essential for stability. These results indicate that the ubiquitin-proteasome system potentiated neurite formation by regulating the stability of TrkA receptors.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제35권5호
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• pp.287-293
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• 2009

Cell survival is the result of a balance between programmed cell death and cellular proliferation. Cell membrane receptors and their associated signal transducing proteins control these processes. Of the numerous receptors and signaling proteins, epidermal growth factor receptor (EGFR) is one of the most important receptors involved in signaling pathways implicated in the proliferation and survival of cancer cells. EGFR is often highly expressed in human tumors including oral squamous cell carcinomas, and there is increasing evidence that high expression of EGFR is correlated with poor clinical outcome of common human cancers. Therefore, we examined the antiproliferative activity of gefitinib, epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI), in head and neck cancer cell lines. SCC-9, KB cells were cultured and growth inhibition activity of gefitinib was measured with MTT assay. To study influence of gefitinib in cell cycle, we performed cell cycle analysis with flow cytometry. Western blot was done to elucidate the expression of EGFR in cell lines and phosphorylation of EGFR and downstream kinase protein, Erk and Akt. Significant growth inhibition was observed in SCC-9 cells in contrast with KB cells. Also, flow cytometric analysis showed G1 phase arrest only in SCC-9 cells. In Western blot analysis for investigation of EGFR expression and downstream molecule phosphorylation, gefitinib suppressed phosphorylation of EGFR and downstream protein kinase Erk, Akt in SCC-9. However, in EGFR positive KB cells, weak expression of active form of Erk and Akt and no inhibitory activity of phosphorylation in Erk and Akt was observed. The antiproliferative activity of gefitinib was not correlated with EGFR expression and some possibility of phosphorylation of Erk and Akt as a predictive factor of gefitinib response was emerged. Further investigations on more reliable predictive factor indicating gefitinib response are awaited to be useful gefitinib treatment in head and neck cancer patients.

• 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.

• Journal of Korean Neurosurgical Society
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• 제29권6호
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• pp.731-737
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• 2000

목 적 : 종양세포의 세포면에서는 성장인자 수용체들이 과발현되고 이들이 성장인자들과 결합함으로서 세포의 성장을 촉진하게 된다. 원발성 악성 뇌종양에 대한 새로운 치료법 중 하나가 면역독소를 사용하는 방법이다. 독소는 대상 세포의 세포면에 있는 수용체를 통해 세포질로 이행되며, 면역독소가 선택적인 항종양작용을 나타내기 위해서는 수용체가 과발현되어야 한다. 강력한 세포독성의 효과가 있음에도 불구하고 면역독소를 환자에 투여하였을 때 종양을 완치시키지는 못하였는데, 면역독소의 효과에 영향을 미치는 여러 인자들에 대한 더 많은 연구가 요구된다. 이러한 연구에 사용되어질 뇌종양세포주들에서 성장인자수용체들의 발현 여부를 알아보기 위해 본 연구를 시행하였다. 대상 및 방법 : 한 개의 수모세포종 세포주(Daoy)와 두 개의 교모세포종 세포주(U373 MG, T98 G)에서, transferrin 수용체, insulin-like growth factor-1 수용체, 그리고 interleukin-4 수용체들의 발현을 flow cytometric analysis를 이용하여 조사하였다. 결 과 : Transferrin 수용체와 interleukin-4 수용체는 Daoy, U373 MG, 그리고 T98 G 모두에서 발현되었다. Insulin-like growth factor-1 수용체는 Daoy와 U373 MG에서는 발현되었지만 T98 G에서는 발현되지 않았다. 결 론 : Transferrin 수용체와 interleukin-4 수용체는 면역독소 치료에 적합한 것으로 보인다. 본 실험의 결과는 상기의 세포주를 사용하여 면역독소와 관련된 실험을 하는데 참고가 되어야하며, 면역독소 치료에 있어서 적절한 면역독소를 선택하는 문제 등 치료 모델을 확립하는데 고려되어야 할 것이다.

• BMB Reports
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• 제43권5호
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• pp.311-318
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• 2010

This review explored the mechanism of breast carcinoma progression by focusing on integrins and receptor tyrosine kinases (or growth factor receptors). While the primary role of integrins was previously thought to be solely as mediators of adhesive interactions between cells and extracellular matrices, it is now believed that integrins also regulate signaling pathways that control cancer cell growth, survival, and invasion. A large body of evidence suggests that the cooperation between integrin and receptor tyrosine kinase signaling regulates certain signaling functions that are important for cancer progression. Recent developments on the crosstalk between integrins and receptor tyrosine kinases, and its implication in mammary tumor progression, are discussed.

• Journal of Microbiology and Biotechnology
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• 제11권4호
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• pp.543-551
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• 2001

The vascular endothelial growth factor (VEGF), or VEGF-A, is intimately involved in both physiological and pathological forms of angiogenesis. VEGF-A is now recognized as the founding member of a family of growth factors that has expanded to include VEGF-B, VEGF-C, VEGF-D, VEGF-E, and placental growth factor (PIGF). This family of cytokines binds differentially to at least three receptor tyrosine kinases, however, the extent to which family members other than VEGF-A contribute to physiological and pathological angiogenesis remains unclear. Issues that are of relevance include uncertainty regarding the consequences of signaling through VEGF - RI in particular, and the ability of some family members to heterodimerize, leading to the possibility ofheterodimeric receptor complexes. Structural characterization is one approach that can be used to address these issues, however, the vast majority of previous structure-function studies have only focused on VEGF-A. While these studies may provide some clues regarding the structural basis of the interaction of other family members with their receptors, studies using the ligands themselves are clearly required if highly specific interactions are to be revealed. With the recent progress toward refolding and purifying substantial' quantities of other VEGF family members, such structural studies are now possible. Here, these ~ssues are addressed with a particular emphasis on VEGF-B and its receptors.

• BMB Reports
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• 제48권6호
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• pp.342-347
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• 2015

The expression of epidermal growth factor receptor (EGFR) is an important diagnostic marker for triple-negative breast cancer (TNBC) cells, which lack three hormonal receptors: estrogen and progesterone receptors as well as epidermal growth factor receptor 2. EGFR transactivation can cause drug resistance in many cancers including TNBC, but the mechanism underlying this phenomenon is poorly defined. Here, we demonstrate that insulin treatment induces EGFR activation by stimulating the interaction of EGFR with insulin-like growth factor receptor 1 (IGF-1R) in the MDA-MB-436 TNBC cell line. These cells express low levels of EGFR, while exhibiting high levels of IGF-1R expression and phosphorylation. Low-EGFRexpressing MDA-MB-436 cells show high sensitivity to insulinstimulated cell growth. Therefore, unexpectedly, insulin stimulation induced EGFR transactivation by regulating its interaction with IGF-1R in low-EGFR-expressing TNBC cells. [BMB Reports 2015; 48(6): 342-347]