• Proceedings of the PSK Conference
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• 2003.04a
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• pp.107-108
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• 2003

The epidermal growth factor (EGF) is an important signaling ligand for the mitogenesis of many cells. The EGF receptors use signaling molecule multicomplexes and dynamic protein networks for the transmission and amplification of the signals as well as for the regulation of the cellular responses. EGF signaling has been reported to be enhanced in various tumors by the overexpressed EGF receptor and/or the mediators such as phospholipase C-$\gamma$1(PLC$\gamma$1). (omitted)

• Maxillofacial Plastic and Reconstructive Surgery
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• v.28 no.6
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• pp.499-510
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• 2006

Malignant tumors of the human salivary glands may arise from major or minor salivary glands. Adenoid cystic carcinoma (ACC) is the second most common malignant neoplasm in the salivary glands. ACC is occasionally highly aggressive tumor that readily invades adjacent tissues and metastasize to distant organs at early stages of the disease. Although ACC tends to grow slowly, treatment outcome may be poor due to wide local infiltration, perineural or intraneural spread and a propensity for hematogenous metastasis. Therefore, knowledge of cellular and molecular characteristics that influence the growth, survival and metastasis of tumor cells, is important for new treatment strategies of salivary ACC. I determined expressions of epiderma growth factor (EGF)-signaling molecules using surgical specimens of human ACCs. Protein expressions of EGF, transforming growth $factor(TGF)-{\alpha}$, EGF receptor (EGFR), phosphorylated EGFR (pEGFR), and human EGF receptor (HER)-2 were assessed in 18 cases of salivary ACC by immunohistochemical staining. Adjacent normal salivary tissues and mucosal tissues, uninvolved by the malignant tumor, served as internal controls. Most of the tumors, especially ACC with a tubulocribriform pattern, were positive for EGF signaling molecules. The overall percentages of the 18 specimens expressing EGF, $TGF-{\alpha}$, EGFR, pEGFR, and HER2 were 50, 89, 61, 61 and 83% respectively. Moreover, tumor-associated endothelial cells and infiltrating immune-related cells in the stroma of ACC, also expressed these biomarkers. Taken together, EGF-signaling molecules are actively expressed in salivary ACC. Therefore, we suggest that these biomarkers can be molecular targets for new treatment strategies of salivary tumors.

• Toxicological Research
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• v.24 no.1
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• pp.1-9
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• 2008

Ptdlns(4,5)$P_2$ is a key cellular phosphoinositide that localizes in separate and distinctive pools in subcellular membrane and vesicular compartments. In membranes, Ptdlns(4,5)$P_2$ acts as a precursor to second messengers and is itself a main signaling and targeting molecule. Specific subcellular localization of type I PIP kinases directed by interacting with specific targeting module differentiates Ptdlns(4,5)$P_2$ production in a spatial and temporal manner. Several lines of evidences support the idea that Ptdlns(4,5)$P_2$ is generated in very specific pools in a spatial and temporal manner or by feeding Ptdlns(4,5)$P_2$ directly to effectors. In this concept, the interaction of PIPKI isoforms with a specific targeting module to allow precise subcellular targeting modulates highly specific Ptdlns(4,5)$P_2$ synthesis and channeling overall effectors. For instance, localization of PIPKI${\gamma}$661 to focal adhesions by an interaction with talin results in spatial and temporal production of Ptdlns(4,5)$P_2$, which regulates EGF-stimulated directional cell migration. In addition, Type $I{\gamma}$ PIPK is targeted to E-cadherin in cell adherence junction and plays a role in controlling dynamics of cell adherence junction and endocytosis of E-cadherin. Characterizing how PIP kinase isoforms are regulated by interactions with their targeting modules, as well as the mechanisms by which their product, Ptdlns(4,5)$P_2$, exerts its effects on cellular signaling processes, is crucial to understand the harmonized control of numerous cellular signaling pathways. Thus, in this review the roles of the Ptdlns(4)P(5) kinases and Ptdlns(4,5)$P_2$ were described and critically reviewed in terms of regulation of the E-cadherin trafficking, cell migration, and formation of cell adherence junction which is indispensable and is tightly controlled in epithelial-to-mesenchymal transition process.

• Molecules and Cells
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• v.45 no.8
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• pp.537-549
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• 2022

Preproenkephalin (PPE) is a precursor molecule for multiple endogenous opioid peptides Leu-enkephalin (ENK) and Met-ENK, which are involved in a wide variety of modulatory functions in the nervous system. Despite the functional importance of ENK in the brain, the effect of brain-derived factor(s) on PPE expression is unknown. We report the dual effect of neural epidermal growth factor (EGF)-like-like 2 (NELL2) on PPE gene expression. In cultured NIH3T3 cells, transfection of NELL2 expression vectors induced an inhibition of PPE transcription intracellularly, in parallel with downregulation of protein kinase C signaling pathways and extracellular signal-regulated kinase. Interestingly, these phenomena were reversed when synthetic NELL2 was administered extracellularly. The in vivo disruption of NELL2 synthesis resulted in an increase in PPE mRNA level in the rat brain, suggesting that the inhibitory action of intracellular NELL2 predominates the activation effect of extracellular NELL2 on PPE gene expression in the brain. Biochemical and molecular studies with mutant NELL2 structures further demonstrated the critical role of EGF-like repeat domains in NELL2 for regulation of PPE transcription. These are the first results to reveal the spatio-specific role of NELL2 in the homeostatic regulation of PPE gene expression.