• International Journal of Oral Biology
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• v.46 no.2
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• pp.81-84
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• 2021

Salivary glands are exocrine glands that secrete saliva into the oral cavity, and secreted saliva plays essential roles in oral health. Therefore, maintaining the salivary glands in an intact state is required for proper production and secretion of saliva. To investigate a specific signaling pathway that might affect the maintenance of mouse submandibular gland (SMGs), RNA sequencing was performed. In SMGs, downregulated expression patterns of Rho-associated protein kinase (ROCK) signaling pathway-related genes, including Rhoa, Rhob, Rhoc, Rock1, and Rock2, were observed. Gene expression profiling analyses of these genes indicate that the ROCK signaling pathway is a potential signal for SMG maintenance.

• The Korean Journal of Physiology and Pharmacology
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• v.17 no.2
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• pp.139-147
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• 2013

Lysolipids such as LPA, S1P and SPC have diverse biological activities including cell proliferation, differentiation, and migration. We investigated signaling pathways of LPA-induced contraction in feline esophageal smooth muscle cells. We used freshly isolated smooth muscle cells and permeabilized cells from cat esophagus to measure the length of cells. Maximal contraction occurred at $10^{-6}M$ and the response peaked at 30s. To identify LPA receptor subtypes in cells, western blot analysis was performed with antibodies to LPA receptor subtypes. LPA1 and LPA3 receptor were detected at 50 kDa and 44 kDa. LPA-induced contraction was almost completely blocked by LPA receptor (1/3) antagonist KI16425. Pertussis toxin (PTX) inhibited the contraction induced by LPA, suggesting that the contraction is mediated by a PTX-sensitive G protein. Phospholipase C (PLC) inhibitors U73122 and neomycin, and protein kinase C (PKC) inhibitor GF109203X also reduced the contraction. The PKC-mediated contraction may be isozyme-specific since only $PKC{\varepsilon}$ antibody inhibited the contraction. MEK inhibitor PD98059 and JNK inhibitor SP600125 blocked the contraction. However, there is no synergistic effect of PKC and MAPK on the LPA-induced contraction. In addition, RhoA inhibitor C3 exoenzyme and ROCK inhibitor Y27632 significantly, but not completely, reduced the contraction. The present study demonstrated that LPA-induced contraction seems to be mediated by LPA receptors (1/3), coupled to PTX-sensitive G protein, resulting in activation of PLC, PKC-${\varepsilon}$ pathway, which subsequently mediates activation of ERK and JNK. The data also suggest that RhoA/ROCK are involved in the LPA-induced contraction.

• The Korean Journal of Food And Nutrition
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• v.29 no.3
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• pp.341-346
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• 2016

Phagocytosis is a primary and an essential step of host defense, and is triggered by the interaction of particles with specific receptor of macrophages. In this study, we investigated the effect of extracts of Rudbeckia laciniata (RLE) on the phagocytic activity of macrophage, by monitoring the phagocytosis-associated signal transduction. RLE markedly increased phagocytosis of serum-opsonized zymosan particles (SOZ), while phagocytosis of IgG-opsonized zymosan particles (IOZ) or none-opsonized zymosan particles (NOZ) remained unaffected. However, RLE did not affect the binding of opsonized zymosan particles (OZ) with the cell surface of macrophage. This suggests that RLE may regulate SOZ-induced intracellular signaling during phagocytosis of macrophage. To confirm this hypothesis, we investigated whether RLE was involved in the RhoA-mediated signal transduction during phagocytosis of SOZ. Inhibitors of the RhoA-mediated signaling pathway, such as Y-27632 (for ROCK), ML-7 (for MLCK), and Tat-C3 (for RhoA), totally blocked phagocytosis of SOZ enhanced by RLE, as well as phagocytosis of SOZ. Additionally, RhoA activity was markedly increased when cells were treated with RLE, suggesting that RLE could increase the phagocytic activity of macrophage via RhoA-ROCK/MLCK signal pathway. Thus, RLE may be used to develop functional foods for immunity.

• BMB Reports
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• v.51 no.12
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• pp.611-612
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• 2018

$C1q/TNF-{\alpha}-Related$ Protein 1 (CTRP1) has recently been shown to act as a blood pressure regulator, as it induces vasoconstriction. In the aorta, CTRP1 facilitates recruitment of angiotensin II receptor 1 (AT1R) to plasma membrane, through activation of the AKT/AS160 signaling pathway. This leads to activation of the Ras homolog gene family (Rho)/Rho kinase (ROCK) signaling pathway, resulting in vasoconstriction. Accordingly, mice overexpressing Ctrp1 have hypertensive phenotype. Patients with hypertension also display higher circulating CTRP1 levels, compared to healthy individuals, indicating that excessive CTRP1 may affect development of hypertension. Conversely, CTRP1 is regarded as an 'innate blood pressure modulator' because CTRP1 increases blood pressure under dehydration to prevent hypotension. Mice lacking Ctrp1 fail to maintain normotension under dehydration conditions, resulting in hypotension, suggesting that CTRP1 is an essential protein for maintaining blood pressure homeostasis. In conclusion, CTRP1 is a novel, anti-hypotensive vasoconstrictor that increases blood pressure during dehydration-induced hypotension.

• Journal of Applied Biological Chemistry
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• v.65 no.4
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• pp.277-286
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• 2022

Schizophragma hydrangeoides (S. hydrangeoides) is a vine endogenous to Jeju Island and Ulleungdo, where it grows attached to the foothills and rock surfaces. Previous research has mostly focused on the whitening effect of S. hydrangeoides leaf extract. In this study, we investigated S. hydrangeoides leaf extract further, and detected four phytochemicals in the extract: chlorogenic acid, quercetin-3-O-glucosyl-(1-2)-rhamnoside, quercetin-3-O-xylosyl-(1-2)-rhamnoside, and quercitrin. We pretreated human dermal fibroblast (HDFn) cells with previously established concentrations of the four compounds for 1 h before ultraviolet A (UVA) irradiation. Among the four compounds, quercetin-3-O-glucosyl-(1-2)-rhamnoside (Q-3-GR) best inhibited matrix metalloproteinase-1 (MMP-1) levels. Thus, we investigated the protective effects of Q-3-GR on photoaging and its underlying mechanisms. Q-3-GR significantly reduced MMP-1 production and inhibited MMP-1 protein expression in UVA-irradiated HDFn cells. Furthermore, Q-3-GR increased procollagen type I production and protein expression. Q-3-GR exerted its anti-photoaging effects by downregulating the mitogen-activated protein kinase/ activator protein-1 signaling pathway, and upregulating the transforming growth factor-β/Smad signaling pathway. Thus, S. hydrangeoides leaf-derived Q-3-GR is a potential potent cosmetic ingredient for UV-induced skin aging.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.22
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• pp.9593-9597
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• 2014

Ursolic acid, extracted from the traditional Chinese medicine bearberry, can induce apoptosis of gastric cancer cells. However, its pro-apoptotic mechanism still needs further investigation. More and more evidence demonstrates that mitochondrial translocation of cofilin-1 appears necessary for the regulation of apoptosis. Here, we report that ursolic acid (UA) potently induces the apoptosis of gastric cancer SGC-7901 cells. Further mechanistic studies revealed that the ROCK1/PTEN signaling pathway plays a critical role in UA-mediated mitochondrial translocation of cofilin-1 and apoptosis. These findings imply that induction of apoptosis by ursolic acid stems primarily from the activation of ROCK1 and PTEN, resulting in the translocation of cofilin-1 from cytoplasm to mitochondria, release of cytochrome c, activation of caspase-3 and caspase-9, and finally inducing apoptosis of gastric cancer SGC-7901 cells.

• The Korean Journal of Physiology and Pharmacology
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• v.22 no.5
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• pp.503-511
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• 2018

Lysophosphatidic acid (LPA) is known to play a critical role in breast cancer metastasis to bone. In this study, we tried to investigate any role of LPA in the regulation of osteoclastogenic cytokines from breast cancer cells and the possibility of these secretory factors in affecting osteoclastogenesis. Effect of secreted cytokines on osteoclastogenesis was analyzed by treating conditioned media from LPA-stimulated breast cancer cells to differentiating osteoclasts. Result demonstrated that IL-8 and IL-11 expression were upregulated in LPA-treated MDA-MB-231 cells. IL-8 was induced in both MDA-MB-231 and MDA-MB-468, however, IL-11 was induced only in MDA-MB-231, suggesting differential LPARs participation in the expression of these cytokines. Expression of IL-8 but not IL-11 was suppressed by inhibitors of PI3K, NF-kB, ROCK and PKC pathways. In the case of PKC activation, it was observed that $PKC{\delta}$ and $PKC{\mu}$ might regulate LPA-induced expression of IL-11 and IL-8, respectively, by using specific PKC subtype inhibitors. Finally, conditioned Medium from LPA-stimulated breast cancer cells induced osteoclastogenesis. In conclusion, LPA induced the expression of osteolytic cytokines (IL-8 and IL-11) in breast cancer cells by involving different LPA receptors. Enhanced expression of IL-8 by LPA may be via ROCK, PKCu, PI3K, and NFkB signaling pathways, while enhanced expression of IL-11 might involve $PKC{\delta}$ signaling pathway. LPA has the ability to enhance breast cancer cells-mediated osteoclastogenesis by inducing the secretion of cytokines such as IL-8 and IL-11.

• The Korean Journal of Physiology and Pharmacology
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• v.5 no.4
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• pp.287-297
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• 2001

Contraction of smooth muscle is initiated by an increase in cytosolic $Ca^{2+}$ leading to activation of $Ca^{2+}$/ calmodulin-dependnet myosin light chain (MLC) kinase and phosphorylation of MLC. The types of contraction and signaling mechanisms mediating contraction differ depending on the region. The involvement of these different mechanisms varies depending on the source of $Ca^{2+}$ and the kinetic of $Ca^{2+}$ mobilization. $Ca^{2+}$ mobilizing agonists stimulate different phospholipases $(PLC-{\beta},\;PLD\;and\;PLA_2)$ to generate one or more $Ca^{2+}$ mobilizing messengers $(IP_3\;and\;AA),$ and diacylglycerol (DAG), an activator of protein kinase C (PKC). The relative contributions of $PLC-{\beta},\;PLA_2$ and PLD to generate second messengers vary greatly between cells and types of contraction. In smooth muscle cell derived form the circular muscle layer of the intestine, preferential hydrolysis of $PIP_2$ and generation of $IP_3$ and $IP_3-dependent\;Ca^{2+}$ release initiate the contraction. In smooth muscle cells derived from longitudinal muscle layer of the intestine, preferential hydrolysis of PC by PLA2, generation of AA and AA-mediated $Ca^{2+}$ influx, cADP ribose formation and $Ca^{2+}-induced\;Ca^{2+}$ release initiate the contraction. Sustained contraction, however, in both cell types is mediated by $Ca^{2+}-independent$ mechanism involving activation of $PKC-{\varepsilon}$ by DAG derived form PLD. A functional linkage between $G_{13},$ RhoA, ROCK, $PKC-{\varepsilon},$ CPI-17 and MLC phosphorylation in sustained contraction has been implicated. Contraction of normal esophageal circular muscle (ESO) in response to acetylcholine (ACh) is linked to $M_2$ muscarinic receptors activating at least three intracellular phospholipases, i.e. phosphatidylcholine-specific phospholipase C (PC-PLC), phospholipase D (PLD) and the high molecular weight (85 kDa) cytosolic phospholipase $A_2\;(cPLA_2)$ to induce phosphatidylcholine (PC) metabolism, production of diacylglycerol (DAG) and arachidonic acid (AA), resulting in activation of a protein kinase C (PKC)-dependent pathway. In contrast, lower esophageal sphincter (LES) contraction induced by maximally effective doses of ACh is mediated by muscarinic $M_3$ receptors, linked to pertussis toxin-insensitive GTP-binding proteins of the $G_{q/11}$ type. They activate phospholipase C, which hydrolyzes phosphatidylinositol bisphosphate $(PIP_2),$ producing inositol 1, 4, 5-trisphosphate $(IP_3)$ and DAG. $IP_3$ causes release of intracellular $Ca^{2+}$ and formation of a $Ca^{2+}$-calmodulin complex, resulting in activation of myosin light chain kinase and contraction through a calmodulin-dependent pathway.

• Radiation Oncology Journal
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• v.19 no.2
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• pp.153-162
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• 2001

Purpose : The mechanical insights of death of cancer cells by ionizing radiation are not of yet clearly defined. Recent evidences have demonstrated that radiation therapy may induce cell death via activation of signaling pathway for apoptosis in target cells. This study is designed whether ionizing radiation may activate the signaling cascades of apoptosis including caspase family cysteine pretenses, $Bcl_2/Bax$, cytochrome c and Fas/Fas-L in target cells. Materials and Methods : HL-60 cells were irradiated in vitro with 6 MV X-ray at dose ranges from 2 Gy to 32 Gy. The cell viability was tested by M assay and the extent of apoptosis was determined using agarose gel electrophoresis. The activities of caspase proteases were measured by proteolytic cleavages of substrates. Western blot analysis was used to monitor PARP, Caspase-3, Cytochrome-c, Bcl-2, Bax, Fas and Fas-L. Results : Ionizing radiation decreases the viability of HL-60 cells in a time and dose dependent manner. Ionizing radiation-induced death in HL-60 cells is an apoptotic death which is revealed as characteristic ladder-pattern fragmentation of genomic DNA over 16 Gy at 4 hours. ionizing radiation induces the activation of caspase-2, 3, 6, 8 and 9 of HL-60 cells in a time-dependent manner. The activation of caspase-3 pretense is also evidenced by the digestion of poly (ADP-ribose) polymerase and procaspase 3 with 16Gy ionizing irradiation. Anti-apoptotic Bcl2 expression is decreased but apoptotic Bax expression is increased with mitochondrial cytochrome c release in a time- dependent manner. In addiiton, expression of Fas and Fas-L is also increased in a time dependent manner. Conclusion : These data suggest that ionizing radiation-induced apoptosis is mediated by the activation of various signaling pathways including caspase family cysteine proteases, $Bcl_2/Bax$, Fas and Fas-L in a time and dose dependent manner.

• International Journal of Oncology
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• v.54 no.6
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• pp.2117-2126
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• 2019

Transforming growth factor-β1 (TGF-β1) is a multifunctional cytokine that functions as a growth suppressor in normal epithelial cells and early stage tumors, but acts as a tumor promoter during malignant progression. However, the molecular basis underlying the conversion of TGF-β1 function remains largely undefined. X-linked inhibitor of apoptosis-associated factor 1 (XAF1) is a pro-apoptotic tumor suppressor that frequently displays epigenetic inactivation in various types of human malignancies, including colorectal cancer. The present study explored whether the anti-apoptotic effect of TGF-β1 is linked to its regulatory effect on XAF1 induction in human colon cancer cells under stressful conditions. The results revealed that TGF-β1 treatment protected tumor cells from various apoptotic stresses, including 5-fluorouracil, etoposide and γ-irradiation. XAF1 expression was activated at the transcriptional level by these apoptotic stresses and TGF-β1 blocked the stress-mediated activation of the XAF1 promoter. The study also demonstrated that mitogen-activated protein kinase kinase inhibition or extracellular signal-activated kinase (Erk)1/2 depletion induced XAF1 induction, while the activation of K-Ras (G12C) led to its reduction. In addition, TGF-β1 blocked the stress-mediated XAF1 promoter activation and induction of apoptosis. This effect was abrogated if Erk1/2 was depleted, indicating that TGF-β1 represses XAF1 transcription through Erk activation, thereby protecting tumor cells from apoptotic stresses. These findings point to a novel molecular mechanism underlying the tumor-promoting function of TGF-β1, which may be utilized in the development of a novel therapeutic strategy for the treatment of colorectal cancer.