• Journal of Pharmacopuncture
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• v.16 no.2
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• pp.55-61
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• 2013

Objective: Ulmi Pumilae Cortex (UPC) is a deciduous tree with uneven pinnate leaves and is classified as a subfamily of Ulmuceae and contains many pharmacologically active constituents. The aim of this study was to investigate the effects of UPC on the growth and survival of AGS cells, the most common human gastric adenocarcinoma cell lines. Methods: The AGS cells were treated with varying concentrations of UPC. Analyses of the sub G1, caspase-3 activity, and mitochondrial depolarization were conducted to determine whether AGS cell death occured by apoptosis. Furthermore, to identify the role of the transient receptor potential melastatin (TRPM) 7 channels in AGS cell growth and survival, we used human embryonic kidney (HEK) 293 cells overexpressed with TRPM7 channels. Results: The addition of UPC to a culture medium inhibited AGS cell growth and survival. Experimental results showed that the sub G1, caspase-3 activity, and mitochondrial depolarization were increased. Furthermore, TRPM7 channel overexpression in HEK 293 cells exacerbated UPC-induced cell death. Conclusion: These findings indicate that UPC inhibits the growth and survival of gastric cancer cells due to a blockade of the TRPM7 channel activity. Therefore, UPC is a potential drug for treatment of gastric cancer, and TRPM7 channels may play an important role in survival in cases of gastric cancer.

• Biomolecules & Therapeutics
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• v.23 no.6
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• pp.539-548
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• 2015

Prostaglandin $E_2$ ($PGE_2$), a major product of cyclooxygenase, binds to four different prostaglandin $E_2$ receptors (EP1, EP2, EP3, and EP4) which are G-protein coupled transmembrane receptors (GPCRs). Although GPCRs including EP receptors have been shown to be associated with their specific G proteins, recent evidences suggest that GPCRs can regulate MAPK signaling via non-G protein coupled pathways including Src. EP2 is differentially expressed in various tissues and the expression of EP2 is induced by extracellular stimuli. We hypothesized that an increased level of EP2 expression may affect MAPK signaling. The overexpression of EP2 in HEK 293 cells resulted in significant increase in intracellular cAMP levels response to treatment with butaprost, a specific EP2 agonist, while overexpression of EP2 alone did not increase intracellular cAMP levels. However, EP2 overexpression in the absence of $PGE_2$ induced an increase in the level of p38 phosphorylation as well as the kinase activity of p38, suggesting that up-regulation of EP2 may promote p38 activation via non-G protein coupled pathway. Inhibition of Src completely blocked EP2-induced p38 phosphorylation and overexpression of Src increased the level of p38 phosphorylation, indicating that Src is upstream kinase for EP2-induced p38 phosphorylation. EP2 overexpression also increased the Src activity and EP2 protein was co-immunoprecipitated with Src. Furthermore, sequential co-immunoprecipitation studies showed that EP2, Src, and ${\beta}$-arrestin can form a complex. Our study found a novel pathway in which EP2 is associated with Src, regulating p38 pathway.

• Journal of Pharmacopuncture
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• v.16 no.3
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• pp.39-45
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• 2013

Objectives: Buxus Microphylla var. Koreana Nakai Extract (BMKNE) is used as a folk remedy for malaria and veneral disease. In the present study, we investigated the effects of BMKNE in the growth and the survival of AGS cells, the most common human gastric adenocarcinoma cell lines. Methods: The AGS cells were treated with varying concentrations of BMKNE. Analyses of the sub G1 peak, the caspase-3 and -9 activities, and the mitochondrial depolarization were conducted to determine whether AGS cell death occured by apoptosis. Also, to identify the role of transient receptor potential melastatin (TRPM) 7 channels in AGS cell growth and survival, we used human embryonic kidney (HEK) 293 cells overexpressed with TRPM7 channels. Results: Experimental results showed that the sub G1 peak, the caspase-3 and -9 activities, and the mitochondrial depolarization were increased. Therefore, BMKNE was found to induce the apoptosis of these cells, and this apoptosis was inhibited by SB203580 (a p38 mitogen-activated protein kinase (MAPK) inhibitor), and by a c-jun NH2-terminal kinase (JNK) II inhibitor. Furthermore, BMKNE inhibited TRPM7 currents and TRPM7 channel over-expressions in HEK 293 cells, exacerbating BMKNE-induced cell death. Conclusions: These findings indicate that BMKNE inhibits the growth and the survival of gastric cancer cells due to a blockade of the TRPM7 channel's activity and MAPK signaling. Therefore, BMKNE is a potential drug for treatment of gastric cancer, and both the TRPM7 channel and MAPK signaling may play an important role in survival in gastric cancer cells.

• The Korean Journal of Physiology and Pharmacology
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• v.17 no.1
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• pp.65-71
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• 2013

The transient receptor potential melastatin type 7 (TRPM7) channel is a widely expressed non-selective cation channel with fusion to the C-terminal alpha kinase domain and regarded as a key regulator of whole body $Mg^{2+}$ homeostasis in mammals. However, the roles of TRPM7 during osteoclastogenesis in RAW264.7 cells and bone marrow-derived monocyte/macrophage precursor cells (BMMs) are not clear. In the present study, we investigate the roles of TRPM7 in osteoclastogenesis using methods of small interfering RNA (siRNA), RT-PCR, patch-clamp, and calcium imaging. RANKL (receptor activator of NF-${\kappa}B$ ligand) stimulation did not affect the TRPM7 expression and TRPM7-mediated current was activated in HEK293, RAW264.7, and BMM cells by the regulation of $Mg^{2+}$. Knock-down of TRPM7 by siTRPM7 reduced intracellular $Ca^{2+}$ concentration ($[Ca^{2+}]_i$) increases by 0 mM $[Mg^{2+}]_e$ in HEK293 cells and inhibited the generation of RANKL-induced $Ca^{2+}$ oscillations in RAW264.7 cells. Finally, knock-down of TRPM7 suppressed RANKL-mediated osteoclastogenesis such as activation and translocation of NFATc1, formation of multinucleated cells, and the bone resorptive activity, sequentially. These results suggest that TRPM7 plays an essential role in the RANKL-induced $[Ca^{2+}]_i$ oscillations that triggers the late stages of osteoclastogenesis.

• Journal of Pharmacopuncture
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• v.15 no.3
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• pp.31-38
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• 2012

Sophorae Radix (SR) plays a role in a number of physiologic and pharmacologic functions in many organs. Objective: The aim of this study was to clarify the potential role for transient receptor potential melastatin 7 (TRPM7) channels in SR-inhibited growth and survival of AGS and MCF-7 cells, the most common human gastric and breast adenocarcinoma cell lines. Methods: The AGS and the MCF-7 cells were treated with varying concentrations of SR. Analyses of the caspase-3 and - 9 activity, the mitochondrial depolarization and the poly (ADPribose) polymerase (PARP) cleavage were conducted to determine if AGS and MCF-7 cell death occured by apoptosis. TRPM7 channel blockers ($Gd^{3+}$ or 2-APB) and small interfering RNA (siRNA) were used in this study to confirm the role of TRPM7 channels. Furthermore, TRPM7 channels were overexpressed in human embryonic kidney (HEK) 293 cells to identify the role of TRPM7 channels in AGS and MCF-7 cell growth and survival. Results: The addition of SR to a culture medium inhibited AGS and MCF-7 cell growth and survival. Experimental results showed that the caspase-3 and -9 activity, the mitochondrial depolarization, and the degree of PARP cleavage was increased. TRPM7 channel blockade, either by $Gd^{3+}$ or 2-APB or by suppressing TRPM7 expression with small interfering RNA, blocked the SR-induced inhibition of cell growth and survival. Furthermore, TRPM7 channel overexpression in HEK 293 cells exacerbated SR-induced cell death. Conclusions: These findings indicate that SR inhibits the growth and survival of gastric and breast cancer cells due to a blockade of the TRPM7 channel activity. Therefore, TRPM7 channels may play an important role in the survival of patients with gastric and breast cancer.

• The Journal of Korean Medicine
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• v.32 no.3
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• pp.35-43
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• 2011

Objectives: This study was performed to screen target-specific inhibitors of ${\beta}$-catenin/TCF signaling whose functional activation plays an important role in early events in carcinogenesis. Methods: To investigate the activation or suppression of ${\beta}$-catenin/TCF transcription, we established a transiently transfected cell line with a constitutively active ${\beta}$-catenin mutant gene whose product is not degraded. This cell line was also co-transfected with luciferase reporter gene constructs containing either an optimized (TOPflash) or mutant (FOPflash) TCF-binding element. We investigated cytotoxic effects using a 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium salt (MTS) assay. To find effective inhibitors of ${\beta}$-catenin/TCF signaling from medicinal herbs, the crude extracts of 99 types of medicinal herbs were screened using a luciferase assay system in HEK-293 and SH-SY5y cells. Results: At a concentration of $50{\mu}g$/ml, extracts of Angelica koreanae radix, Cannabis sativa semen, Ephedrae intermedia Schrenk radix, and Vitis rotundifolia fruit showed the following inhibitory effects on ${\beta}$-catenin/TCF signaling: $40{\pm}5.6%$, $23{\pm}6.1%$, $8{\pm}5.1%$, and $22{\pm}9.8%$ in ${\beta}$-catenin-activated HEK-293 cells and $9{\pm}4.7%$, $39{\pm}8.1%$, $39{\pm}6.4%$, and $42{\pm}10.1%$ in ${\beta}$-catenin-activated SH-SY5y cells, respectively. Crude extracts of E. radix were isolated by silica gel column chromatography, and two non-polar fractions of these extracts showed inhibitory effects on ${\beta}$-catenin/TCF signaling. Conclusions: In this study, we established a transiently transfected cell line as a screening system and found that various medicinal herb extracts had inhibitory effects on ${\beta}$signaling.

• Korean Journal of Plant Resources
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• v.29 no.5
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• pp.620-624
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• 2016

The Wnt/β-catenin signaling pathway is mandatory in adipogenesis. In this study, we investigated the applicability of functional materials for the treatment of obesity by examining Wnt/β-catenin pathway reporter activity related to adipocyte differentiation inhibiting with korean native plant extracts. The luciferase activity of HEK 293-TOP cells increased the reporter activity approximately 152% and 130% by treatment with Sanguisorba officinalis and Thuja orientalis, respectively. Ricinus communis were represented about 90% higher activity, two samples(Rosa rugosa and Sophorae Flos) showed 80% higher activity than the control. Three samples of plant extracts (Zanthoxylum piperitum, Pueraria thunbergiana, Solanum nigrum) were about 70% higher activity compared with the non-treated control. Cytotoxicity of plant extracts was not detected in the rat neural stem cells. These results suggest that the selected eight plant extracts are safe compounds. Our findings indicate that Wnt/β-catenin pathway reporter activity could be used for high throughput screening system. In addition, the plant extracts selected as candidates for adipocyte differentiation inhibiting may be potential therapeutic agents for obesity, it will be exploring the possibility of developing an anti-obesity materials through further experiments with selected plant extracts.

• BMB Reports
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• v.44 no.5
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• pp.352-357
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• 2011

The effect of human MutY homolog (hMYH) on the activation of checkpoint proteins in response to hydroxyurea (HU) and ultraviolet (UV) treatment was investigated in hMYH-disrupted HEK293 cells. hMYH-disrupted cells decreased the phosphorylation of Chk1 upon HU or UV treatment and increased the phosphorylation of Cdk2 and the amount of Cdc25A, but not Cdc25C. In siMYH-transfected cells, the increased rate of phosphorylated Chk1 upon HU or UV treatment was lower than that in siGFP-transfected cells, meaning that hMYH was involved in the activation mechanism of Chk1 upon DNA damage. The phosphorylation of ataxia telangiectasia and Rad3-related protein (ATR) upon HU or UV treatment was decreased in hMYH-disrupted HEK293 and HaCaT cells. Co-immunoprecipitation experiments showed that hMYH was immunoprecipitated by anti-ATR. These results suggest that hMYH may interact with ATR and function as a mediator of Chk1 phosphorylation in response to DNA damage.

• Nutrition Research and Practice
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• v.8 no.4
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• pp.377-385
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• 2014

BACKGROUND/OBJECTIVES: Abundant consumption of seaweeds in the diet is epidemiologically linked to the reduction in risk of developing cancer. In larger cases, however, identification of particular seaweeds that are accountable for these effects is still lacking, hindering the recognition of competent dietary-based chemo preventive approaches. The aim of this research was to establish the antiproliferative potency and angiosuppressive mode of action of Stoechospermum marginatum seaweed methanolic extract using various experimental models. MATERIALS/METHODS: Among the 15 seaweeds screened for antiproliferative activity against Ehrlich ascites tumor (EAT) cell line, Stoechospermum marginatum extract (SME) was found to be the most promising. Therefore, it was further investigated for its anti-proliferative activity in-vitro against choriocarcinoma (BeWo) and non-transformed Human embryonic kidney (HEK 293) cells, and for its anti-migratory/tube formation activity against HUVEC cells in-vitro. Subsequently, the angiosuppressive activity of S. marginatum was established by inhibition of angiogenesis in in-vivo (peritoneal angiogenesis and chorioallantoic membrane assay) and ex-vivo (rat cornea assay) models. RESULTS: Most brown seaweed extracts inhibited the proliferation of EAT cells, while green and red seaweed extracts were much less effective. According to the results, SME selectively inhibited proliferation of BeWo cells in-vitro in a dose-dependent manner, but had a lesser effect on HEK 293 cells. SME also suppressed the migration and tube formation of HUVEC cells in-vitro. In addition, SME was able to suppress VEGF-induced angiogenesis in the chorio allantoic membrane, rat cornea, and tumor induced angiogenesis in the peritoneum of EAT bearing mice. A decrease in the microvessel density count and CD31 antigen staining of treated mice peritoneum provided further evidence of its angiosuppressive activity. CONCLUSIONS: Altogether, the data underline that VEGF mediated angiogenesis is the target for the angiosuppressive action of SME and could potentially be useful in cancer prevention or treatment involving stimulated angiogenesis.

• BMB Reports
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• v.41 no.10
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• pp.716-721
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• 2008

To explore the effects of deregulated expression of the EBNA1 binding protein 2 (EBP2) on cell growth, we generated human HEK293 stable clones constitutively expressing an EBP2-EGFP fusion protein. We found both RNA and protein levels of cyclin E1, a dominant oncoprotein, were elevated in the EBP2- EGFP stable clones. These findings were confirmed by flow cytometry bivariate analysis of cyclin expression versus DNA content. Moreover, the increase in p21 expression and the specific phosphorylation at Ser1981 of ATM and Ser15 of p53 were also observed in these stable clones, and these observations may explain the failure to observe an increase in Cdk2 kinase activity. In addition, after one year of passage culture, the EBP2-EGFP stable clones tended to lose 4 to 5 chromosomes per cell when compared to that of control cells. All of these findings provide a possible link between deregulated expression of EBP2 and tumor development.