• Biomolecules & Therapeutics
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• 제25권3호
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• pp.321-328
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• 2017

Steroid sulfatase (STS) is an enzyme responsible for the hydrolysis of aryl and alkyl sulfates. STS plays a pivotal role in the regulation of estrogens and androgens that promote the growth of hormone-dependent tumors, such as those of breast or prostate cancer. However, the molecular function of STS in tumor growth is still not clear. To elucidate the role of STS in cancer cell proliferation, we investigated whether STS is able to regulate the integrin signaling pathway. We found that overexpression of STS in HeLa cells increases the protein and mRNA levels of integrin ${\beta}1$ and fibronectin, a ligand of integrin ${\alpha}5{\beta}1$. Dehydroepiandrosterone (DHEA), one of the main metabolites of STS, also increases mRNA and protein expression of integrin ${\beta}1$ and fibronectin. Further, STS expression and DHEA treatment enhanced phosphorylation of focal adhesion kinase (FAK) at the Tyr 925 residue. Moreover, increased phosphorylation of ERK at Thr 202 and Tyr 204 residues by STS indicates that STS activates the MAPK/ERK pathway. In conclusion, these results suggest that STS expression and DHEA treatment may enhance MAPK/ERK signaling through up-regulation of integrin ${\beta}1$ and activation of FAK.

• Molecules and Cells
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• 제41권3호
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• pp.188-197
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• 2018

Benzidine, a known carcinogen, is closely associated with the development of bladder cancer (BC). Epithelial-mesenchymal transition (EMT) is a critical pathophysiological process in BC progression. The underlying molecular mechanisms of mitogen-activated protein kinase (MAPK) pathway, especially extracellular regulated protein kinases 5 (ERK5), in regulating benzidine-induced EMT remains unclarified. Hence, two human bladder cell lines, T24 and EJ, were utilized in our study. Briefly, cell migration was assessed by wound healing assay, and cell invasion was determined by Transwell assay. Quantitative PCR and western blot were utilized to determine both gene expressions as well as protein levels of EMT and MAPK, respectively. Small interfering RNA (siRNA) was transfected to further determine ERK5 function. As a result, the migration and invasion abilities were enhanced, epithelial marker expression was decreased while mesenchymal marker expression was increased in human BC cell lines. Meanwhile, benzidine administration led to activation of ERK5 and activator protein 1 (AP-1) proteins, without effective stimulation of the Jun N-terminal kinase (JNK) or p38 pathways. Moreover, Benzidine-induced EMT and ERK5 activation were completely suppressed by XMD8-92 and siRNAs specific to ERK5. Of note, ERK1/2 was activated in benzidine-treated T24 cells, while benzidine-induced EMT could not be reversed by U0126, an ERK1/2 inhibitor, as indicated by further study. Collectively, our findings revealed that ERK5-mediated EMT was critically involved in benzidine-correlated BC progression, indicating the therapeutic significance of ERK5 in benzidine-related BC.

• 대한본초학회지
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• 제22권2호
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• pp.147-153
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• 2007

Objectives : Sophora flavescens (SF) is widely used in traditional herbal medicine in Korea and is well recognized for its anti-inflammatory effect. However, its effect on Tumornecrosis factor alpha (Tnf) production in BV2 microglial cell is not yet known. Methods : We investigated the effect of SF on the production and expression of Tnf, a well known inflammatory mediator, in lipopolysaccaride (LPS)-activated BV2 microglial cells. Results : The LPS-induced Tnf production was markedly reduced by treatment with SF (50 ${\mu}g/ml$). In reverse transcription polymerase chain reaction (RT-PCR) analysis, SF suppressed the LPS activated expression of Tnf mRNA. In addition, Western blot analysis confirmed that SF suppressed the expression of Tnf. Sophora flavescens also inhibited the LPS-induced phosphylation of extracellular signal-regulated kinases (ERK), which mediate the Tnfproduction signaling pathway whereas LPS-induced phosphylation of p38 mitogen activated protein kinase (p38 MAPK), and c-Jun NH2-terminal kinases (JNK) was not inhibited by SF, which implies that SF suppresses LPS-induced Tnf production via the ERK mediated pathway. Conclusion : Taken together, these findings indicated that SF inhibits LPS-induce Tnf production, and that this inhibitory effect is mediated via the ERK pathway.

• Archives of Pharmacal Research
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• 제26권9호
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• pp.739-746
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• 2003

Ultraviolet B (UVB) is known to induce apoptosis in human melanocytes. Here we show the cytoprotective effect of sphingosine-1-phosphate (S1P) against UVB-induced apoptosis. We also show that UVB-induced apoptosis of melanocytes is mediated by caspase-3 activation and poly(ADP-ribose) polymerase (PARP) cleavage, and that S1P prevents apoptosis by inhibiting this apoptotic pathway. We further investigated three major mitogen-activated protein (MAP) kinases after UVB irradiation. UVB gradually activated c-Jun N-terminal kinase (JNK) and p38 MAP kinase, while extracellular signal-regulated protein kinase (ERK) was inactivated transiently. Blocking of the p38 MAP kinase pathway using SB203580 promoted cell survival and inhibited the activation of caspase-3 and PARP cleavage. These results suggest that p38 MAP kinase activation may play an important role in the UVB-induced apoptosis of human melanocytes. To explain this cytoprotective effect, we next examined whether S1P could inhibit UVB-induced JNK and p38 MAP kinase activation. However, S1P was not found to have any influence on UVB-induced JNK or p38 MAP kinase activation. In contrast, S1P clearly stimulated the phosphorylation of ERK, and the specific inhibition of the ERK pathway using PD98059 abolished the cytoprotective effect of S1P. Based on these results, we conclude that the activation of p38 MAP kinase plays an important role in UVB-induced apoptosis, and that S1P may show its cytoprotective effect through ERK activation in human melanocytes.

• Asian Pacific Journal of Cancer Prevention
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• 제13권12호
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• pp.6155-6157
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• 2012

Background: Mutations in the MAPK (Mitogen Activated Protein Kinase) signaling pathway - EGFR/Ras/RAF/MEK have been associated with the development of several carcinomas. ERK2, a downstream target of the MAPK pathway and a founding member of the MAPK family is activated by cellular signals emanating at the cell membrane. Activated ERK2 translocates into the nucleus to transactivate genes that promote cell proliferation. MKP - a dual specific phosphatase - interacts with activated ERK2 via the common docking (CD) domain of the later to inactivate (dephosphorylate) and effectively terminate further cell proliferation. A constitutively active form of ERK2 carrying a single point mutation - E322K in its CD domain, was earlier reported by our laboratory. In the present study, we investigated the prevalence of this CD domain E322K mutation in 88 well differentiated OSCC tissue samples. Materials and Method: Genomic DNA specimens isolated from 88 oral squamous cell carcinoma tissue samples were amplified with primers flanking the CD domain of the ERK2 gene. Subsequently, PCR amplicons were gel purified and subjected to direct sequencing to screen for mutations. Results: Direct sequencing of eighty eight OSCC samples identified an E322K CD domain mutation in only one (1.1%) OSCC sample. Conclusions: Our result indicates that mutation in the CD domain of ERK2 is rare in OSCC patients, which suggests the role of genetic alterations in other mitogenic genes in the development of carcinoma in the rest of the patients. Nevertheless, the finding is clinically significant, as the relatively rare prevalence of the E322K mutation in OSCC suggests that ERK2, being a common end point signal in the multi-hierarchical mitogen activated signaling pathway may be explored as a viable drug target in the treatment of OSCC.

• 생명과학회지
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• 제21권4호
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• pp.534-541
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• 2011

Retinoic acid (RA)는 Vitamin A의 대사산물로서 토끼 관절 연골세포의 탈분화를 유도하는 물질로 알려져 있다. 그러나 RA가 탈분화를 조절하는 정확한 메커니즘은 잘 알려져 있지 않다. 따라서, Nitric Oxide (NO)가 유도하는 탈분화에 미치는 RA의 분자적 기전에 관한 연구를 수행하였다. 그 결과, RA는 NO가 유도하는 탈분화를 촉진시키는 것을 확인 할 수 있었다. 이와 같은 결과는 Western blot analysis를 통해 연골세포 분화의 표지 단백질인 type II collagen 및 Sox-9의 발현양상을 통해 확인 할 수 있었으며, Alcian blue staining을 통해 연골세포의 기질을 구성하고 있는 단백질인 sulfated proteoglycan의 발현량을 통해서도 확인 할 수 있었다. 또한, RA는 NO 가 유도하는 ERK의 활성을 더욱 증가 시켰다. ERK의 억제자인 PD98059를 사용하여 ERK의 활성을 억제하였을 때 RA가 감소시키는 type II collagen 및 Sox-9의 발현과 sulfated proteoglycan의 생성 양상이 PD98059에 의해 다시 회복되는 것을 확인 할 수 있었다. 이러한 모든 결과를 종합해 볼 때, RA는 NO가 유도하는 탈분화를 ERK 신호전달경로를 통해 조절하는 것을 확인 할 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제26권6호
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• pp.1063-1066
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• 2016

Longan (Dimocarpus longan Lour.) has been used as a traditional oriental medicine and possesses a number of physiological activities. In this study, we used cell-based herbal extract screening to identify longan fruit extract (LFE) as an activator of osteoblast differentiation. LFE up-regulated alkaline phosphatase (ALP) activity, induced mineralization, and activated Runx2 gene expression in MC3T3-E1 cells. Furthermore, treatment of MC3T3-E1 cells with LFE promoted the phosphorylation of extracellular signal-regulated kinase1/2 (Erk1/2); however, abrogation of Erk1/2 activation with PD98059 resulted in down-regulation of the phospho-SMAD1/5/8 and Runx2 levels, which in turn reduced the ALP activity. Our findings suggest that LFE exerts its osteogenic activity through activation of the ERK signaling pathway and may have potential as an herbal therapeutic or a preventive agent for the treatment of osteoporosis.

• BMB Reports
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• 제57권5호
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• pp.250-255
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• 2024

Due to their stem-like characteristics and immunosuppressive properties, Mesenchymal stem cells (MSCs) offer remarkable potential in regenerative medicine. Much effort has been devoted to enhancing the efficacy of MSC therapy by enhancing MSC migration. In this study, we identified deubiquitinase BRCA1-associated protein 1 (BAP1) as an inhibitor of MSC migration. Using deubiquitinase siRNA library screening based on an in vitro wound healing assay, we found that silencing BAP1 significantly augmented MSC migration. Conversely, BAP1 overexpression reduced the migration and invasion capabilities of MSCs. BAP1 depletion in MSCs upregulates ERK phosphorylation, thereby increasing the expression of the migration factor, osteopontin. Further examination revealed that BAP1 interacts with phosphorylated ERK1/2, deubiquitinating their ubiquitins, and thus attenuating the ERK signaling pathway. Overall, our study highlights the critical role of BAP1 in regulating MSC migration through its deubiquitinase activity, and suggests a novel approach to improve the therapeutic potential of MSCs in regenerative medicine.

• Molecules and Cells
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• 제27권3호
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• pp.351-357
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• 2009

Phytoestrogens are the natural compounds isolated from plants, which are structurally similar to animal estrogen, $17{\beta}$-estradiol. Tectoridin, a major isoflavone isolated from the rhizome of Belamcanda chinensis. Tectoridin is known as a phytoestrogen, however, the molecular mechanisms underlying its estrogenic effect are remained unclear. In this study we investigated the estrogenic signaling triggered by tectoridin as compared to a famous phytoestrogen, genistein in MCF-7 human breast cancer cells. Tectoridin scarcely binds to ER ${\alpha}$ as compared to $17{\beta}$-estradiol and genistein. Despite poor binding to ER ${\alpha}$, tectoridin induced potent estrogenic effects, namely recovery of the population of cells in the S-phase after serum starvation, transactivation of the estrogen response element, and induction of MCF-7 cell proliferation. The tectoridin-induced estrogenic effect was severely abrogated by treatment with U0126, a specific MEK1/2 inhibitor. Tectoridin promoted phosphorylation of ERK1/2, but did not affect phosphorylation of ER ${\alpha}$ at $Ser^{118}$. It also increased cellular accumulation of cAMP, a hallmark of GPR30-mediated estrogen signaling. These data imply that tectoridin exerts its estrogenic effect mainly via the GPR30 and ERK-mediated rapid nongenomic estrogen signaling pathway. This property of tectoridin sets it aside from genistein where it exerts the estrogenic effects via both an ER-dependent genomic pathway and a GPR30-dependent nongenomic pathway.

• 동의생리병리학회지
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• 제23권2호
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• pp.416-425
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• 2009

Angiogenesis is important for promoting cardiovascular disease, wound healing, and tissue regeneration. We here investigated the pharmacological effects of Korea red ginseng water extract (KRGE) on angiogenesis and its underlying signal mechanism. This study showed that KRGE increased in vitro proliferation, migration, and tube formation of human umbilical endothelial cells, as well as stimulated in vivo angiogenesis. KRGE-induced angiogenesis was accompanied by phosphorylation of ERK1/2, Akt, and endothelial nitric oxide synthase (eNOS) as well as an increase in NO production. Inhibition of PI3K activity by wortmannin completely inhibited KRGE-induced angiogenesis and phosphorylation of Akt, ERK1/2, and eNOS, indicating that PI3K/Akt activation is an upstream event of KRGE-mediated angiogenic pathway. The MEK inhibitor PD98059 completely blocked KRGE-induced angiogenesis and ERK phosphorylation without affecting Akt and eNOS activation. However, the eNOS inhibitor NMA effectively inhibited tube formation, but partially blocked proliferation and migration as well as ERK phosphorylation without altering Akt and eNOS activation, revealing that eNOS/NO pathway is in part involved in ERK1/2 activation. This study first demonstrated the critical involvement of both ERK1/2 and eNOS activation in KRGE-induced angiogenesis, which lie on downstream of PI3K/Akt. Thus, these results indicate that KRGE requires activation of both the PI3K/Akt-dependent ERK1/2 and eNOS signal pathways and their cross-talk for its full angiogenic activity.