• The Korean Journal of Physiology and Pharmacology
• /
• 제17권2호
• /
• pp.157-162
• /
• 2013

Insulin-like growth factor binding proteins (IGFBPs) are important components of insulin growth factor (IGF) signaling pathways. One of the binding proteins, IGFBP-5, enhances the actions of IGF-1, which include the enhanced proliferation of smooth muscle cells. In the present study, we examined the expression and the biological effects of IGFBP-5 in vascular smooth muscle cells (VSMCs) from spontaneously hypertensive rats (SHR) and Wistar Kyoto rats (WKY). The levels of IGFBP-5 mRNA and protein were found to be higher in the VSMC from SHR than in those from WKY. Treatment with recombinant IGFBP-5-stimulated VSMC proliferation in WKY to the levels observed in SHR. In the VSMCs of WKY, incubation with angiotensin (Ang) II or IGF-1 dose dependently increased IGFBP-5 protein levels. Transfection with IGFBP-5 siRNA reduced VSMC proliferation in SHR to the levels exhibited in WKY. In addition, recombinant IGFBP-5 significantly up-regulated ERK1/2 phosphorylation in the VSMCs of WKY as much as those of SHR. Concurrent treatment with the MEK1/2 inhibitors, PD98059 or U0126 completely inhibited recombinant IGFBP-5-induced VSMC proliferation in WKY, while concurrent treatment with the phosphatidylinositol-3 kinase inhibitor, LY294002, had no effect. Furthermore, knockdown with IGFBP-5 siRNA inhibited ERK1/2 phosphorylation in VSMC of SHR. These results suggest that IGFBP-5 plays a role in the regulation of VSMC proliferation via ERK1/2 MAPK signaling in hypertensive rats.

• BMB Reports
• /
• 제36권5호
• /
• pp.468-474
• /
• 2003

The molecular mechanism of hypoxia-induced apoptosis has not been clearly elucidated. In this study, we investigated the involvement of extracellular signal-regulated protein kinase (ERK 1/2) in hypoxia-induced apoptosis using cobalt chloride in HeLa human cervical cancer cells. The cobalt chloride was used for the induction of hypoxia, and its $IC_{50}$ was $471.4\;{\mu}M$. We demonstrated the DNA fragmentation after incubation with concentrations more than $50\;{\mu}M$ cobalt chloride for 24 h, and also evidenced the morphological changes of the cells undergoing apoptosis with electron microscopy. Next, we examined the signaling pathway of cobalt chloride-induced apoptosis in HeLa cells. ERK1/2 activation occurred 6 and 9 h after treatment with $600\;{\mu}M$ cobalt chloride. Meanwhile, the pretreatment of the MEK 1 inhibitor (PD98059) completely blocked the cobalt chloride-induced ERK 1/2 activation. At the same time, the activated ERK 1/2 translocated into the nucleus and phosphorylated its transcriptional factor, c-Jun. In addition, the pretreatment of PD98059 inhibited the cobalt chloride-induced DNA fragmentation and apoptotic cell death. These results suggest that cobalt chloride is able to induce apoptotic activity in HeLa cells, and its apoptotic mechanism may be associated with signal transduction via ERK 1/2.

• Asian Pacific Journal of Cancer Prevention
• /
• 제15권5호
• /
• pp.2369-2374
• /
• 2014

Background and Aim: Selumetinib is a promising and interesting targeted therapy agent as it may reverse radioiodine uptake in patients with radioiodine-refractory differentiated thyroid cancer. We conduct this metaanalysis to compare the efficacy and safety of selumetinib with current therapies in patients with advanced cancer. Methods: An electronic search was conducted using PubMed/ Medicine, EMBASE and Cochrane library databases. Statistical analyses were carried out using either random-effects or fixed-effects models according to the heterogeneity of eligible studies. Results: Six eligible trials involved 601 patients were identified. Compared with current therapies, treatment schedules with selumetinib did not improve progression free survival (hazard ratio, 0.91; 95%CI 0.70-1.17, P= 0.448), but did identify better clinical benefits (odds ratio, 1.24; 95%CI 0.69-2.24, P = 0.472) and less disease progression (hazard ratio, 0.72; 95%CI 0.51-1.00, P = 0.052) though its impact was not statistically significant. Sub-group analysis resulted in significantly improved progression free survival (hazard ratio, 0.61; 95%CI 0.49-0.57, P = 0.00), clinical benefits (odds ratio, 3.04; 95%CI 1.60-5.77, P = 0.001) and reduced disease progression (hazard ratio, 0.35; 95%CI 0.18-0.67, P = 0.001) in patients administrated selumetinib. Dermatitis acneiform (risk ratio, 9.775; 95%CI 3.143-30.395, P = 0.00) and peripheral edema (risk ratio, 2.371; 95%CI 1.690-3.327, P = 0.00) are the most frequently observed adverse effects associated with selumetinib. Conclusions: Compared with current chemotherapy, selumetinib has modest clinical activity as monotherapy in patients with advanced cancer, but combinations of selumetinib with cytotoxic agents in patients with BRAF or KRAS mutations hold great promise for cancer treatment. Dermatitis acneiform and peripheral edema are the most frequently observed adverse effects in patients with selumetinib.

• 한국발생생물학회지:발생과생식
• /
• 제6권1호
• /
• pp.1-6
• /
• 2002

세포외기질(exrtracellular matrix, ECM)에 의한 생쥐 초기 배아의 발생 조절 현상의 기작 규명을 위한 연구의 일환으로 Engelbreth-Holm-Swarm(EHS) mouse sarcoma의 세포외기질로부터 추출한 ECM 복합체인 Matrigel의 성장인자 제거형(GFR-Matrigel)을 생쥐 포배에 처리한 후 mitogen activated protein kinase (MAPK, ERK1/2) 활성 의 변화를 조사하였다. Matrigel 처리 후 10분 이내에 배아의 MAPK 활성이 유의하게 증가하였고, 60분 후에도 유의하게 높은 활성을 유지하였다. 한편 MAPK cascade의 저해제인 PD098059를 전처리한 경우 Matrigel에 의한 MAPK 활성의 증가가 관찰되지 않았다. Matrigel 배양액 내에서 12시간 동안 배양한 포배의 MAPK 활성은 대조군과는 현격한 차이를 보였다. 이러한 결과로부터 ECM에 의한 생쥐초기 배아의 발생 촉진효과 발현기작에는 하위 신호전달 과정의 MAPK 활성화 과정이 관여하는 것으로 사료된다.

• Molecules and Cells
• /
• 제39권10호
• /
• pp.742-749
• /
• 2016

The cancer chemo-preventive effects of equol have been demonstrated for a wide variety of experimental tumours. In a previous study, we found that equol inhibited proliferation and induced apoptotic death of human gastric cancer MGC-803 cells. However, the mechanisms underlying equol-mediated apoptosis have not been well understood. In the present study, the dual AO (acridine orange)/EB (ethidium bromide) fluorescent assay, the comet assay, MTS, western blotting and flow cytometric assays were performed to further investigate the pro-apoptotic effect of equol and its associated mechanisms in MGC-803 cells. The results demonstrated that equol induced an apoptotic nuclear morphology revealed by AO/EB staining, the presence of a comet tail, the cleavage of caspase-3 and PARP and the depletion of cIAP1, indicating its pro-apoptotic effect. In addition, equol-induced apoptosis involves the mitochondria-dependent cell-death pathway, evidenced by the depolarization of the mitochondrial membrane potential, the cleavage of caspase-9 and the depletion of Bcl-xL and full-length Bid. Moreover, treating MGC-803 cells with equol induced the sustained activation of extracellular signal-regulated kinase (ERK), and inhibiting ERK by U0126, a MEK/ERK pathway inhibitor, significantly attenuated the equol-induced cell apoptosis. These results suggest that equol induces mitochondria-dependent apoptosis in human gastric cancer MGC-803 cells via the sustained activation of the ERK1/2 pathway. Therefore, equol may be a novel candidate for the chemoprevention and therapy of gastric cancer.

• Clinical and Experimental Reproductive Medicine
• /
• 제30권1호
• /
• pp.5-14
• /
• 2003

Objective: Present study was aimed to verify the effect of granulocyte macrophage-colony stimulating factor (GM-CSF) in the preimplantation development of mouse embryos and the involvement of the mitogen activated protein kiase (MAPK) in the GM-CSF signaling. Methods: Two-cell embryos were cultured for 96 h in the presence or absence of GM-CSF (0, 0.4, 2, 10 ng/ml) and PD98059, a MEK inhibitor (10 ${\mu}M$). Morphological development, cell number per blastocyst, and apoptotic nuclei, were eamined. MAPK activity of embryonic immunoprecipitate by MAPK (ERK1/2) antibody was measured by in vitro phosphorylation of myelin basic protein. Results: At post hCG 122 h the embryonic development among the experimental groups was significantly different (p=0.018). The rate of blastocyst development and cell number per embryo were the highest in 2 ng/ml GM-CSF treatment group. The percent of apoptotic cells of the GM-CSF-treated embryos was the lowest among the group. In blastocysts, GM-CSF treatment transiently increased MAPK activity. PD098059 attenuated the effect of GM-CSF on the morphological development, increase in cell number per blastocyst, down regulation of apoptosis, and upregulation of MAPK activity, suggesting that activation of MAPK cascade possibly mediated the embryotropic effect of GM-CSF. Conclusion: This result suggested that GM-CSF potentiated the development of preimplantation mouse embryos by activation of MAPK.

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

• 한국발생생물학회지:발생과생식
• /
• 제22권2호
• /
• pp.133-142
• /
• 2018

Patients with type II diabetes mellitus are more susceptible to colorectal cancer (CRC) incidence than non-diabetics. The anti-diabetic drug metformin is most commonly prescribed for the treatment of this disease and has recently shown antitumor effect in preclinical studies. The aberrant mutational activation in the components of RAS/RAF/MEK/ERK and PI3K/AKT/mTOR signaling pathway is very frequently observed in CRC. We previously reported that metformin inhibits the phosphorylation of ERK and BEZ235, a dual inhibitor of PI3K and mTOR, has anti-tumor activity against HCT15 CRC cells harboring mutations of KRAS and PIK3CA. Therefore, we hypothesized that simultaneous inhibition of two pathways by combining metformin with BEZ235 could be more effective in the suppression of proliferation than single agent treatment in HCT15 CRC cells. Here, we investigated the combinatory effect of metformin and BEZ235 on the cell survival in HCT15 CRC cells. Our study shows that both of the two signaling pathways can be blocked by this combinational strategy: metformin suppressed both pathways by inhibiting the phosphorylation of ERK, 4E-BP1 and S6, and BEZ235 suppressed PI3K/AKT/mTOR pathway by reducing the phosphorylation of 4E-BP1 and S6. This combination treatment synergistically reduced cell viability. The combination index (CI) values ranged from 0.44 to 0.88, indicating synergism for the combination. These results offer a preclinical rationale for the potential therapeutic option for the treatment of CRC.

• Tuberculosis and Respiratory Diseases
• /
• 제56권6호
• /
• pp.638-645
• /
• 2004

연구배경 : Uteroglobin은 정상 폐상피세포에서 발현되는 단백질로 비소세포암 조직이나 세포주에서는 발현이 저하되어있다. 항염증작용을 하며 암세포에 과발현 시키면 암의 형질이 소실됨이 밝혀지고 있다. 역시 염증작용과 관련이 있는 cPLA2와 COX-2도 암과의 관련성이 밝혀지고 있고, 암억제나 MMP의 억제 등의 공통점을 가지고 있으나 이들의 관련성에 대해서는 밝혀진 바가 없다. 또한, COX-2의 암과의 관련성을 설명하는 기전으로 ERK 활성화의 관련 가능성이 있으나, uteroglobin과 ERK의 관련성도 아직 밝혀지지 않고 있다. 비소세포폐암 세포주에 uteroglobin을 과발현시킨 후, cPLA2와 COX-2의 발현, 그리고 MMP-2, MMP-9, ERK의 활성화가 어떻게 변화하는지에 대해 실험하였다. 방 법 : 폐선암세포주인 A549와 NCI-H460 세포주에 adenovirus-uteroglobin, adenovirus-null을 각각 20,100,200 moi로 transduction 시킨 뒤, 48시간 배양한 후에 단백질을 추출하였다. Uteroglobin의 발현을 확인한 후, cPLA2, COX-2, pERK, total ERK에 대해 Western blot을 시행하였고, 배양액으로 zymography를 시행하였다. 결 과 : A549 세포주와 NCI-H460 세포주에서 uteroglobin의 발현을 확인한 세포주에서 cPLA2와 COX-2의 발현이 감소함을 Western blot으로 확인하였고, pERK가 증가함을 Western blot으로 보았고, ERK의 활성화가 증가함을 확인하였다. MMP-9은 활성이 저하되었고, MMP-2는 변화가 없었다. MEK inhibitor인 U0126을 이용하여 ERK의 활성화를 저해시킨 후, uteroglobin의 발현에는 영향이 없었고, MMP-9의 활성저하효과가 소실되었다. 결 론 : 폐암세포주에서 uteroglobin의 항암작용기전에 cPLA2 와 COX-2의 발현의 감소와 ERK의 활성화가 기여할 것으로 사료된다.

• Molecules and Cells
• /
• 제40권7호
• /
• pp.457-465
• /
• 2017

Streptozotocin (STZ)-induced murine models of type 1 diabetes have been used to examine ER stress during pancreatic ${\beta}$-cell apoptosis, as this ER stress plays important roles in the pathogenesis and development of the disease. However, the mechanisms linking type 1 diabetes to the ER stress-modulating anti-diabetic signaling pathway remain to be addressed, though it was recently established that ERK5 (Extracellular-signal-regulated kinase 5) contributes to the pathogeneses of diabetic complications. This study was undertaken to explore the mechanism whereby ERK5 inhibition instigates pancreatic ${\beta}$-cell apoptosis via an ER stress-dependent signaling pathway. STZ-induced diabetic WT and CHOP deficient mice were i.p. injected every 2 days for 6 days under BIX02189 (a specific ERK5 inhibitor) treatment in order to evaluate the role of ERK5. Hyperglycemia was exacerbated by co-treating C57BL/6J mice with STZ and BIX02189 as compared with mice administered with STZ alone. In addition, immunoblotting data revealed that ERK5 inhibition activated the unfolded protein response pathway accompanying apoptotic events, such as, PARP-1 and caspase-3 cleavage. Interestingly, ERK5 inhibition-induced exacerbation of pancreatic ${\beta}$-cell apoptosis was inhibited in CHOP deficient mice. Moreover, transduction of adenovirus encoding an active mutant form of $MEK5{\alpha}$, an upstream kinase of ERK5, inhibited STZ-induced unfolded protein responses and ${\beta}$-cell apoptosis. These results suggest that ERK5 protects against STZ-induced pancreatic ${\beta}$-cell apoptosis and hyperglycemia by interrupting the ER stress-mediated apoptotic pathway.