• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.93.3-94
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• 2003

The signaling components of high affinity IgE receptor (Fc RI) were searched by yeast-hybrid screening of the cDNA library constructed from RBL-2H3 cells. The cytoplasmic part of the Fc RI- chain was found to specifically interact with PLC 2, and further comparatives studies were conducted focusing on the differential regulation of two PLC- isoforms through Fc RI. The inhibitors of Src, Syk, and protein kinase C similarly affected the tyrosine phosporylations of PLC 1 and PLC 2 but the inhibitors of PI3-kinase and p42/44 ERK effectively inhibited the activation of PLC 1 but not PLC 2. (omitted)

• IMMUNE NETWORK
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• 제21권2호
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• pp.16.1-16.8
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• 2021

Patients with severe coronavirus disease 2019 (COVID-19) demonstrate dysregulated immune responses including exacerbated neutrophil functions. Massive neutrophil infiltrations accompanying neutrophil extracellular trap (NET) formations are also observed in patients with severe COVID-19. However, the mechanism underlying severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-induced NET formation has not yet been elucidated. Here we show that 2 viral proteins encoded by SARS-CoV-2, the nucleocapsid protein and the whole spike protein, induce NET formation from neutrophils. NET formation was ROSindependent and was completely inhibited by the spleen tyrosine kinase inhibition. The inhibition of p38 MAPK, protein kinase C, and JNK signaling pathways also inhibited viral protein-induced NET formation. Our findings demonstrate one method by which SARSCoV-2 evades innate immunity and provide a potential target for therapeutics to treat patients with severe COVID-19.

• The Korean Journal of Physiology and Pharmacology
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• 제4권6호
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• pp.507-513
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• 2000

ErbB3/HER3 is a cell surface receptor which belongs to the ErbB/HER subfamily of receptor protein tyrosine kinases. When expressed in NIH/3T3 cells, ErbB3 can form heterodimeric coreceptor with endogenous ErbB2. Among known intracellular effectors of the ErbB2/ErbB3 are mitogen-activated protein kinase (MAPK) and phosphoinositide (PI) 3-kinase. In the present study, we studied relative contributions of above two distinct signaling pathways to the heregulin-induced mitogenic response via activated ErbB3. For this, clonal NIH-3T3 cell lines expressing wild-type ErbB3 and ErbB3 mutants were stimulated with $heregulin{\beta}_1$. While cyclin D1 level was markedly high and further increased by treatment of heregulin in cells expressing wild-type ErbB3, the elimination of either Shc binding or PI 3-kinase binding lowered both levels. This result was supported by the reduction of cyclin $D_1$ expression by preteatment with MAPK kinase inhibitor or PI 3-kinase inhibitor before stimulation with heregulin. In accordance with the cyclin $D_1$ expression, elimination of either Shc binding or PI 3-kinase binding reduced the heregulin-induced DNA synthesis and cell growth rate. Our results obtained by the comparison of wild-type and ErbB3 mutants indicate that the full induction of the cell cycle progression through $G_1/S$ phase by ErbB3 activation is dependent on both Shc/MAPK and PI 3-kinase signal transduction pathways.

• The Journal of Korean Physical Therapy
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• 제20권3호
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• pp.53-59
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• 2008

Purpose: The non-receptor-type protein tyrosine kinase Syk (636 amino acids, 72 kDa) is ubiquitously expressed in hematopoietic stem cells and has been widely studied as a regulator and effector of B cell receptor signaling that occurs in processes such as differentiation, proliferation and apoptosis. However, the mechanism relating Syk and p38 mitogen-activated protein kinases (p38MAPK) by endothelin-1 (ET-1, 21 amino acids) stimulation in muscle cells, especially in the volume-dependent hypertensive state, remains unclear. Methods: In this study, we investigated the relationship between Syk and p38MAPK for isometric contraction and enzymatic activity by ET-1 from rat aortic smooth muscle cells and aldosterone-analogue deoxycorticosterone acetate (DOCA) hypertensive state rats (ADHR). Results: The systolic blood pressure was significantly increased in ADHR than in a control group of animals. ET-1 induced isometric contraction and phosphorylation of p38MAPK, which was increased in muscle strips from ADHR. Increased vasoconstriction and phosphorylation of p38MAPK induced by treatment with 30 nM ET-1 were inhibited by the use of 10${\mu}M$ SB203580, an inhibitor of p38MAPK from ADHR. Furthermore, ET-1 induced isometric contraction and phosphorylation of Syk and p38MAPK, which were increased in the aortic smooth muscle cells. Increased tension and phosphorylation of Syk and p38MAPK induced by ET-1 were inhibited by SB203580 from rat aortic smooth muscle cells. Conclusion: These results, suggest that the Syk activity affects ET-1-induced contraction through p38MAPK in smooth muscle cells and that the same pathway directly or indirectly is associated with volume dependent hypertension. The findings suggest the need to develop cardiovascular disease-specialized physical therapy.

• BMB Reports
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• 제36권3호
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• pp.288-293
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• 2003

Low molecular weight phosphotyrosine protein phosphatase (LMW-PTP) has been implicated in modulating the EphB1-mediated signaling pathway. In this study, we demonstrated that the EphA8 receptor phosphorylates LMW-PTP in vitro. In addition, we discovered that mixing these two proteins leads to EphA8 dephosphorylation in the absence of phosphatase inhibitors. Finally, we demonstrated that LMW-PTP, modified by the EphA8 autokinase activity, possesses enhanced catalytic activity in vitro. These results suggest that LMW-PTP may also participate in a feedback-control mechanism of the EphA8 receptor autokinase activity in vivo.

• Archives of Pharmacal Research
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• 제21권5호
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• pp.487-495
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• 1998

Gorwth factors such as TGF-beta, PDGF and FGF are thought to play important roles in wound healing. However, thier biological activity and signal transduction during wound repair remain poorly understood. Growth factors are often ligands for receptor tyrosine kinase and receptor serine/threonine kinases. With recent advances in signal transduction by receptor kinases, we are beginning to understand the underlying mechanism of how growth factors may regulate cutaneous wound repair. In this paper, we will describe the pharmacological effects of growth factors on wound healing, and dscuss the potential underlying signaing mechanisms. thus, we hope to provide the basis for designing more specific therapeutics for wound healing in the near future.

• 셀메드
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• 제3권2호
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• pp.10.1-10.8
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• 2013

Cancer is one of the major dreaded diseases causing high mortality. Lung cancer is second in position of all cancer related deaths and mainly divided into two morphologic sub-types: small-cell lung cancer and non-small cell lung cancer (NSCLC). NSCLC is an aggressive neoplasm which hardly responds to any conventional chemotherapy. Epidermal growth factor receptor (EGFR) belongs to the ErbB family of receptor tyrosine kinase that is mainly over-expressed in NSCLC. EGFR is mainly involved in the pathogenesis and progression of different carcinoma. In vivo and in vitro studies suggest that EGFR and EGF like peptides are often over-expressed in human NSCLC and these proteins are able to induce cell transformation. The conventional therapies mostly inhibit the EGFR activity and expression level in human NSCLC with the use of some EGFR-inhibitors like HKI-272, EKB569, CL-387785 etc. and some synthetic chemotherapeutic drugs like erlotinib, gefitinib, plumbagin, docetaxel, cisplatin etc., alone or in combination of two or more drugs. These therapies selectively act by competitive inhibition of the binding of adenosine triphosphate to the tyrosine kinase domain of the EGFR, resulting in inhibition of the EGFR signaling pathway. But these chemotherapeutic drugs have some cytotoxic activities to the normal cells and have some adverse side-effects. Recent studies on some traditional alternative therapies including some herbal and plant extracts, active ingredients like curcumin, different homeopathic drugs, etc. can target EGFR-signalling in NSCLC with less toxic side-effects are being currently developed.

• Tuberculosis and Respiratory Diseases
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• 제74권3호
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• pp.129-133
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• 2013

The presence of epidermal growth factor receptor (EGFR ) mutation is a prognostic and predictive marker for EGFR-tyrosine kinase inhibitor (TKI) therapy. However, inevitably, relapse occurs due to the development of acquired resistance, such as T790M mutation. We report a case of repeated responses to EGFR-TKIs in a never-smoked woman with adenocarcinoma. After six cycles of gemcitabine and cisplatin, the patient was treated by gefitinib for 4 months until progression. Following the six cycles of third-line pemetrexed, gefitinib retreatment was initiated and continued with a partial response for 6 months. After progression, she was recruited for an irreversible EGFR inhibitor trial, and the time to progression was 11 months. Although EGFR direct sequencing on the initial diagnostic specimen revealed a wild-type, we performed a rebiopsy from the progressed subcarinal node at the end of the trial. The result of peptide nucleic acid clamping showed L858R/L861Q.

• Asian Pacific Journal of Cancer Prevention
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• 제15권7호
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• pp.3185-3189
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• 2014

Background: Breast cancer evolution and tumor progression are controlled by complex interactions between steroid receptors and growth factor receptor signaling. Aberrant growth factor receptor signaling can augment or suppress estrogen receptor function in hormone-dependent breast cancer cells. Thus, we aimed to investigate antitumor effects of sorafenib and lapatinib alone and in combination on MCF-7 breast cancer cells. Materials and Methods: Cytotoxicity of the sorafenib and lapatinib was tested in MCF-7 cells by XTT assays. 50, 25, 12.5 and $6.25{\mu}M$ concentrations of sorafenib and 200, 100, 50 and $25{\mu}M$ concentrations of lapatinib were administered alone and in combination. Results were evaluated as absorbance at 450nM and $IC_{50}$ values are calculated according to the absorbance data Results: Both sorafenib and lapatinib showed concentration dependent cytotoxic effects on MCF-7 cells. Sorafenib exerted cytotoxic effects with an $IC_{50}$ value of $32.0{\mu}M$; in contrast with lapatinib the $IC_{50}$ was $136.6{\mu}M$. When sorafenib and lapatinib combined, lapatinib increased cytotoxic effects of sorafenib at its ineffective concentrations. Also at the concentrations where both drugs had cytotoxic effects, combination show strong anticancer effects and killed approximately 70 percent of breast cancer cells. Conclusions: Combinations of tyrosine kinase inhibitors and cytotoxic agents or molecular targeted therapy has been successful for many types of cancer. The present study shows that both sorafenib and lapatinib alone are effective in the treatment of breast cancer. Also a combination of these two agents may be a promising therapeutic option in treatment of breast cancer.

• BMB Reports
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• 제54권12호
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• pp.626-631
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• 2021

Janus kinase 2 (JAK2), a non-receptor tyrosine kinase, is a critical component of cytokine and growth factor signaling pathways regulating hematopoietic cell proliferation. JAK2 mutations are associated with multiple myeloproliferative neoplasms. Although physiological and pathological functions of JAK2 in hematopoietic tissues are well-known, such functions of JAK2 in the nervous system are not well studied yet. The present study demonstrated that JAK2 could negatively regulate neuronal differentiation of mouse embryonic stem cells (ESCs). Depletion of JAK2 stimulated neuronal differentiation of mouse ESCs and activated glycogen synthase kinase 3β, Fyn, and cyclin-dependent kinase 5. Knockdown of JAK2 resulted in accumulation of GTP-bound Rac1, a Rho GTPase implicated in the regulation of cytoskeletal dynamics. These findings suggest that JAK2 might negatively regulate neuronal differentiation by suppressing the GSK-3β/Fyn/CDK5 signaling pathway responsible for morphological maturation.