• Tuberculosis and Respiratory Diseases
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• v.56 no.6
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• pp.638-645
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• 2004

Background : Uteroglobin is a protein produced by the normal bronchial epithelium and its expression level is lower in non-small cell lung cancer tissues and cell lines. It mainly functions as an anti-inflammatory, and when it is overexpressed in cancer cells, the neoplastic phenotype is antagonized. cPLA2 and COX-2, which are also associated with inflammation, were reported to be related to cancer. The relationship between cPLA2, COX-2 and uteroglobin is unclear. The relationship between uteroglobin and ERK, which is related to cell growth, is also not unclear. This study investigated the changes in the cPLA2 and COX-2 expression levels and the ERK activities after the overexpression of uteroglobin in non-small cell lung cancer cell lines. Methods : The A549 and NCI-H460 cell lines were infected by adenovirus-null and adenovirusuteroglobin. The cChange in the cPLA2, COX-2 expression level and ERK activity after uteroglobin overexpression was measured by Western blot. The change in MMP activity was measured by zymography. Results : Western blot revealed decreased expression levels of cPLA2, and COX-2, and increased pERK levels in nonsmall cell lung cancer cells after uteroglobin overexpression. Zymography revealed no changes in the MMP-2 activity and lower MMP-9 activity. U0126, which is a specific inhibitor of ERK-activating kinase MEK-1/-2, prevented the decrease in the MMP-9 activity Conclusions : A decrease in cPLA2 expression, COX-2 expression, MMP-9 activity and a increase in ERK activity may be related to the anticancer effects of uteroglobin in nonsmall cell lung cancer cells.

• Environmental Mutagens and Carcinogens
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• v.25 no.2
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• pp.51-59
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• 2005

Overexpression of HSP25 delayed cell growth, increased the level of $p21^{waf}$, reduced the levels of cyclin D1, cylcin A and cdc2, and induced radioresistance in L929 cells. We demonstrated that extracellular regulated kinase (ERK) and MAP kinase/ERK kinase (MEK) expressions as well as their activation (phospho-forms) were inhibited by hsp25 overexpression. To confirm the relationship between ERK1/2 and hsp25-mediated radioresistance, ERK1 or ERK2 cDNA was transiently transfected into the hsp25 overexpressed cells and their radioresistance was examined. HSP25-mediated radioresistance was abolished by overexpression of ERK2, but not by overexpression of ERK1. Alteration of cell cycle distribution and cell cycle related protein expressions (cyclin D, cyclin A and cdc2) by hsp25 overexpression were also recovered by ERK2 cDNA transfection. Increase in Bc1-2 protein by hsp25 gene transfection was also reduced by subsequent ERK2 cDNA-transfection. In addition, HSP25 overexpression reduced reactive oxygen species (ROS) and increased expression of manganese superoxide dismutase (MnSOD) gene. Increased activation of NF-kB (IkB degradation) was also found in hsp25-overexpressed cells. Moreover, transfection of hsp25 antisense gene abrogated all the HSP25-mediated phenomena. To further elucidate the exact relationship between MnSOD induction and NF-kB activation, dominant negative $I-kB\alpha(I-kB\alpha-DN)$ construction was transfected to HSP25 overexpressed cells. $I-kB\alpha-DN$ inhibited HSP25 mediated MnSOD gene expression. In addition, HSP25 mediated radioresistance was blocked by $I-kB\alpha-DN$ transfection. Blockage of MnSOD with antisense oligonucleotides in HSP25 overexpressed cells, prevented apoptosis and returned the ERK1/2 activation to the control level. From the above results, we suggest for the first time that reduced oxidative damage by HSP25 was due to MnSOD-mediated down regulation of ERK1/2.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.12
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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.

• Clinical and Experimental Reproductive Medicine
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• v.33 no.2
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• pp.105-113
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• 2006

Objective: To investigate the role of ERK and $PPAR{\gamma}$ on the $TGF-{\beta}1$ induced human endometrial stromal cell decidualization in vitro. Method: Endometrial stromal cells are cultured under the following condition: DMEM/F12 (10% FBS, 1 nM E2 and 100 nM P4). $TGF-{\beta}1$ (5 ng/ml), Rosiglitazone (50 nM), and PD98059 ($20{\mu}M$) were added according to experimental purposes. Trypan-Blue and hematocytometer were utilized to count cell number. Enzyme-linked immunosorbent assay (ELISA) and western blotting were utilized to detect proteins. Result: $TGF-{\beta}1$ inhibited proliferation of cultured human endometrial stromal cells and induced expression of PGE2 and prolactin. This effect was mediated by Smad and ERK activation. Administration of rosiglitazone, $PPAR{\gamma}$ agonist, prevented $TGF-{\beta}1$ effect on cell proliferation. Furthermore, Rosiglitazone inhibited $TGF-{\beta}1$ induced activation of ERK, consequently reduced PGE2 and prolactin production. Conclusion: $TGF-{\beta}1$ induced decidualization of endometrial stromal cell through Smad and ERK phosphorylation. $PPAR{\gamma}$ acts as a negative regulator of human ndometrial cell decidualization in vitro.

• Journal of Pharmacopuncture
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• v.6 no.2
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• pp.77-90
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• 2003

The purpose of this study was to investigate the effect of Bee Venom on the lipopolysaccharide(LPS), sodium nitroprusside(SNP), hydrogen peroxide($H_2O_2$)-induced expressions of cyclooxygenase-2(COX-2), p38, jun N-terminal Kinase(JNK) and extra-signal response kinase(ERK) in RAW 264.7 cells, a murine macrophage cell line. Method : The expressions of COX-2, p38, JNK and ERK were determined by western blotting with corresponding antibodies. Results : 1. The 0.5, 1 and $5\;{\mu}g/ml$ of bee venom inhibited significantly LPS and SNP-induced expression of COX-2 compared with control, respectively. The 0.5, 1 and $5\;{\mu}g/ml$ of bee venom inhibited insignificantly $H_2O_2$-induced expression of COX-2 compared with control, respectively. 2. The 0.5, 1 and $5\;{\mu}g/ml$ of bee venom inhibited significantly LPS, SNP and $H_2O_2$-induced expression of p38 compared with control, respectively. 3. The 1 and $5\;{\mu}g/ml$ of bee venom inhibited significantly SNP-induced expression of JNK compared with control, respectively. All of bee venom inhibited insignificantly LPS and $H_2O_2$-induced expression of JNK compared with control, respectively. 4. The $5\;{\mu}g/ml$ of bee venom inhibited significantly SNP-induced expression of ERK, the $0.5\;{\mu}g/ml$ of bee venom increased significantly $H_2O_2$-induced expression of ERK compared with control. The 0.5, 1 and $5\;{\mu}g/ml$ of bee venom inhibited insignificantly LPS-induced expression of ERK compared with control, respectively.

• The Korean Journal of Physiology and Pharmacology
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• v.13 no.3
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• pp.161-168
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• 2009

In the peripheral nerves, injury-induced cytokines and growth factors perform critical functions in the activation of both the MEK/ERK and JAK/STAT3 pathways. In this study, we determined that nerve injury-induced ERK activation was temporally correlated with STAT3 phosphorylation at the serine 727 residue. In cultured Schwann cells, we noted that ERK activation is required for the serine phosphorylation of STAT3 by neuropoietic cytokine interleukin-6 (IL-6). Serine phosphorylated STAT3 by IL-6 was transported into Schwann cell nuclei, thereby indicating that ERK may regulate the transcriptional activity of STAT3 via the induction of serine phosphorylation of STAT3. Neuregulin-1 (NRG) also induced the serine phosphorylation of STAT3 in an ERK-dependent fashion. In contrast with the IL-6 response, serine phosphorylated STAT3 induced by NRG was not detected in the nucleus, thus indicating the non-nuclear function of serine phosphorylated STAT3 in response to NRG. Finally, we determined that the inhibition of ERK prevented injury-induced serine phosphorylation of STAT3 in an ex-vivo explants culture of the sciatic nerves. Collectively, the results of this study show that ERK may be an upstream kinase for the serine phosphorylation of STAT3 induced by multiple stimuli in Schwann cells after peripheral nerve injury.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.6
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• pp.2495-2499
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• 2015

Mitogen-activated protein kinase/extracellular signal-regulated kinase kinase kinase 3 (MEKK3) is an important serine/threonine protein kinase and a member of the MAPK family. MEKK3 can effectively activate the MEK/ERK signaling pathway and promote an autocrine growth loop critical for tumor genesis, cell proliferation, terminal differentiation, apoptosis and survival. To explore the relationship between MEKK3 and cell apoptosis, clinicopathology and prognosis, we characterize the expression of MEKK3, pERK and FoxP3 in the renal clear cell carcinoma (RCCC). Protein expression was detected by tissue microarray and immunochemistry in 46 cases of RCCC and 28 control cases. Expression levels of CD3+,CD3+CD4+,CD3+CD8+,CD4+CD25+, CD4+CD25+ FoxP3+ were assessed by flow cytometry and analyzed for their association with pathological factors, correlation and prognosis in RCCC. Expression of MEKK3, pERK and FoxP3 was significantly up-regulated in RCCC as compared to control levels (p<0.01), associated with pathological grade (p<0.05)and clinical stage (p<0.05). CD4+CD25+ Foxp3+ Treg cells were also significantly increased in RCCC patients (p<0.05). Cox multivariate regression analysis showed that MEKK3, pERK expression and patholigical stage were independent prognostic factors in patients with RCCC (p<0.05). MEKK3 can be used as an important marker of early diagnosis and prognostic evaluation in RCCC. It may be associated with imbalance of anti-tumor immunity and overexpression of pERK. Expression of MEKK3 and pERK are significantly increased in RCCC, with protein expression and clinical stage acting as independent prognostic factors.

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.2
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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.

• Molecules and Cells
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• v.25 no.2
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• pp.184-195
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• 2008

We examined the role of c-FLIP in the motility of HeLa cells. A small interfering RNA (siRNA) directed against c-FLIP inhibited the adhesion and motility of the cells without affecting their growth rate. The long form of c-FLIP ($c-FLIP_L$), but not the short form ($c-FLIP_S$), enhanced adhesion and motility. Downregulation of $c-FLIP_L$ with siRNA decreased phosphorylation of FAK and ERK, while overexpression of $c-FLIP_L$ increased their phosphorylation. Overexpression of FAK activated ERK, and enhanced the motility of HeLa cells. FRNK, an inhibitory fragment of FAK, inhibited ERK and decreased motility. Inhibition of ERK also significantly suppressed $c-FLIP_L$-promoted motility. Inhibition of ROCK by Y27632 suppressed the $c-FLIP_L$-promoted motility by reducing phosphorylation of FAK and ERK. Overexpression of $c-FLIP_L$ increased the expression and secretion of MMP-9, and inhibition of MMP-9 by Ilomastat reduced $c-FLIP_L$- promoted cell motility. A caspase-like domain (amino acids 222-376) was found to be necessary for the $c-FLIP_L$-promoted cell motility. We conclude that $c-FLIP_L$ promotes the motility of HeLa cells by activating FAK and ERK, and increasing MMP-9 expression.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.20
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• pp.8539-8548
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• 2014

Mitogen-activated protein kinase (MAPK) is an important signaling pathway in living beings in response to extracellular stimuli. There are 5 main subgroups manipulating by a set of sequential actions: ERK(ERK1/ERK2), c-Jun N(JNK/SAPK), p38 MAPK($p38{\alpha}$, $p38{\beta}$, $p38{\gamma}$ and $p38{\delta}$), and ERK3/ERK4/ERK5. When stimulated, factors of upstream or downstream change, and by interacting with each other, these groups have long been recognized to be related to multiple biologic processes such as cell proliferation, differentiation, death, migration, invasion and inflammation. However, once abnormally activated, cancer may occur. Several components of the MAPK network have already been proposed as targets in cancer therapy, such as p38, JNK, ERK, MEK, RAF, RAS, and DUSP1. Among them, alteration of the RAS-RAF-MEK-ERK-MAPK(RAS-MAPK) pathway has frequently been reported in human cancer as a result of abnormal activation of receptor tyrosine kinases or gain-of-function mutations in genes. The reported roles of MAPK signaling in apoptotic cell death are controversial, so that further in-depth investigations are needed to address these controversies. Based on an extensive analysis of published data, the goal of this review is to provide an overview on recent studies about the mechanism of MAP kinases, and how it generates certain tumors, as well as related treatments.