Expression Levels Of Extracellular Signal-regulated Kinase Research Articles

Anti-calcitonin gene-related peptide antibody attenuates orofacial mechanical and heat hypersensitivities induced by infraorbital nerve injury

Currently, limited information regarding the role of calcitonin gene-related peptide (CGRP) in neuropathic pain is available. Intracerebroventricular administrations of an anti-CGRP antibody were performed in rats with infraorbital nerve ligation. Anti-CGRP antibody administration attenuated mechanical and heat hypersensitivities induced by nerve ligation and decreased the phosphorylated extracellular signal-regulated kinase expression levels in the trigeminal spinal subnucleus caudalis (Vc) following mechanical or heat stimulation. An increased CGRP immunoreactivity in the Vc appeared after nerve ligation. A decreased CGRP immunoreactivity resulted from anti-CGRP antibody administration. Our findings suggest that anti-CGRP antibody administration attenuates the symptoms of trigeminal neuropathic pain by acting on CGRP in the Vc.

Electroacupuncture improves cutaneous allergic reaction by inhibiting degranulation of intrape-ritoneal mast cells, MAPK signaling and inflammatory factor levels in urticaria rats

To observe the effect of electroacupuncture (EA) on degranulation of intraperitoneal mast cells (MCs) and expression of mitogen-activated protein kinase (MAPK) signaling related proteins, tumor necrosis factor-α(TNF-α) and interleukin-6 (IL-6) in urticaria rats, so as to reveal its mechanisms underlying improvement of urticaria. Thirty-two SD rats were randomly divided into control，model，EA and medication groups (n＝8 in each group). The urticaria model was established by using passive cutaneous anaphylaxis (PCA) reaction method. EA (2 Hz /15 Hz, 1 mA) was applied to bilateral "Zusanli"(ST36), "Quchi "(LI11) and "Xuehai"(SP10) for 20 min，once daily for 7 consecutive days before antigen attack. Rats of the medication group were treated by gavage of Loratadine(1 mg•kg－1•d－1)for 7 days. The diameter of cutaneous Evan's blue spots was measured to evaluate the severity of PCA. Intraperitoneal fluid smears were prepared to observe the degranulation state of MCs. The contents of TNF-α and IL-6 in the intraperitoneal fluid were detected by ELISA, and the expression of extracellular signal-regulated kinase (ERK), phosphorylated (p)-ERK, c-Jun N-terminal kinase (JNK), p-JNK, P38MAPK and p-P38MAPK of the acquired intraperitoneal MCs was detected by Western blot. The diameter of cutaneous Evan's blue spot was significantly increased in the model group than that in the control group (P<0.01), and considerably decreased in both EA and medication groups compared with the model group(P<0.01). After modeling，the percentage of degranulated MCs, contents of TNF-α and IL-6, and expression levels of ERK, p-ERK, JNK, p-JNK, P38MAPK and p-P38MAPK were remarkably increased in the mo-del group than those in the control group (P<0.01, P<0.05). After the treatment, the percentage of degranulated MCs, contents of TNF-α and IL-6, and expression levels of p-ERK, JNK, p-JNK and p-P38MAPK were obviously decreased in both EA and medication groups relevant to the model group (P<0.01, P<0.05), while no significant changes were found in the expression of ERK in both EA and medication groups, and P38MAPK in the EA group. Compared with the model and EA groups, expression levels of P38MAPK were down-regulated in the medication group (P<0.05). EA can reduce skin allergic reaction in rats with urticaria, which may be related to its effects in inhibiting the degranulation of intraperitoneal MCs, down-regulating the expression of MAPK signaling-related proteins and the level of pro-inflammatory factors TNF-α and IL-6 in intraperitoneal MCs.

Acetyl-11-keto-β-boswellic acid regulates the repair of rat sciatic nerve injury by promoting the proliferation of Schwann cells

AimsThis study aimed to study the effects of acetyl-11-keto-β-boswellic acid (AKBA) on the regeneration of injured peripheral nerves and the ability of the extracellular signal-regulated kinase (ERK) signaling pathway to regulate the proliferation of Schwann cells and the formation of myelin. Main methodsA sciatic nerve crush injury model rats were randomly divided into the model control, low-, medium-, and high-dose AKBA groups. The repair of myelin damage was observed through Luxol Fast Blue staining and the expression of neurofilament-200 (NF200) protein was detected through immunohistochemical tests. The relative expression levels of ERK, Phosphorylated-ERK (p-ERK), c-Jun N-terminal Kinase (JNK), and Phosphorylated-JNK (p-JNK) proteins were detected in vitro in Schwann cells treated with AKBA. The effect of AKBA on P0 and P75 protein expression in Schwann cells was detected through siRNA-mediated ERK gene knockout. Key findingsAKBA promotes the repair of rat sciatic nerve injury by elevating the phosphorylation of the ERK signaling pathway and by regulating the proliferation and myelination of Schwann cells. SignificanceThis test can provide data support for AKBA to repair sciatic nerve injury, provide a theoretical basis for further revealing AKBA repair mechanism, and provide reference for clinical development of sciatic nerve injury drugs.

Comparative study of the efficacy of pulsed electromagnetic field and low level laser therapy on mitogen-activated protein kinases

Mitogen-Activated Protein Kinases (MAPKs) consist of three major signaling members: extracellular signal-regulated kinase (ERK), p38 and C-JUN N-terminal kinase (JNK). We investigated physiological effects of Pulsed Electromagnetic Field Therapy (PEMFT) and Low Level Laser Therapy (LLLT) on human body, adopting the expression level of mitogen-activated protein kinases as an indicator via assessment of the activation levels of three major families of MAPKS, ERK, p38 and JNK in the peripheral lymphocytes of patients before and after the therapies. Assessment for the expression levels of MAPKs families' were done, in the peripheral lymphocytes of patients recently have appendectomy, using flow cytometric analysis of multiple signaling pathways, pre and post LLLT and PEMFT application (twice daily for 6 successive days) on the appendectomy wound. There were non-significant differences in the expression levels of MAPKs families' pre- therapies application. But there were significant increase in the ERK expression levels post application of LLLT compared to its pre application (p<0.01). Also, there was significant increase in the ERK, p38 and C-Jun N terminal expression level values post application of PEMFT compared to its pre application expression levels (p<0.01 for each). The present study demonstrates that PEMFT has a powerful healing effect more than LLLT as it increase the activation of ERK, P38 and C-Jun-N Terminal while LLLT only increase the activation of ERK. LLLT has more potent pain decreasing effect than PEMFT as it does not activate P38 pathway like PEMFT.

Kai-Xin-San, a traditional Chinese medicine formulation, exerts antidepressive and neuroprotective effects by promoting pCREB upstream pathways.

Kai-Xin-San (KXS) is a traditional Chinese medicine that has been widely used for the treatment of emotion-related disease. However, the underlying mechanism remains largely unknown. The present study aimed to examine whether phospho-cAMP response element-binding protein (pCREB) and upstream components, such as extracellular signal-regulated kinase (ERK), phospho-ERK (pERK), phosphatidylinositol-3-kinase (PI3K), protein kinase B (Akt), glycogen synthase kinase 3β (GSK3β) and pGSK3β are associated with the antidepressive effect of KXS. In total, 24 male Wistar rats were randomly divided into three groups, including control (n=8, no treatment), induced with chronic unpredictable mild stress (CMS) (n=8), and CMS rats treated with KXS at dosage of 370 mg/kg/day orally. Primary hippocampal neuronal cultures were prepared from Wistar rats for cell survival and proliferation assays. In KXS rats, increased protein expression levels of pCREB, BDNF and tyrosine receptor kinase B (TrkB) were observed in the hippocampus and prefrontal cortex, compared with the CMS model group. Furthermore, increased expression levels of ERK, pERK, PI3K, Akt, and GSK3β were also detected in the hippocampus and prefrontal cortex of KXS-treated rats compared with CMS model rats and in primary hippocampal neuronal cells treated with KXS. These results suggest that pCREB and upstream components, including TrkB/ERK/CREB and TrkB/PI3 K/CREB, may contribute to the antidepressive effect induced by KXS. Further studies are required to confirm these findings.

Transcriptional Repression of Mad-Max Complex by Human Umbilical Cord Blood Stem Cells Downregulates Extracellular Signal-Regulated Kinase in Glioblastoma

Previously, we have shown that human umbilical cord blood stem cell (hUCBSC) treatment downregulate cyclin D1 in glioma cells. To study the cell cycle progression and investigate the upstream molecules regulating cyclin D1 expression, we analyzed the involvement of extracellular signal-regulated kinase (ERK) and its functionality after treatment with hUCBSC. We observed downregulation of pERK after hUCBSC treatment at both transcriptional and translational levels. Increased translocation of ERK from cytoplasm to the nucleus was observed in glioma cells, whereas hUCBSC cocultures with glioma cells showed suppressed nuclear translocation. This finding suggests that hUCBSC regulates ERK by suppressing its phosphorylation at phospho-Thr(202)/Tyr(204) retarding pERK nuclear translocation. ERK promoter analysis has shown c-Myc binding sites, indicative of possible transcriptional interactions that regulate cyclin D1 and ERK expression levels. Treatment of U251 and 5310 glioma cells with U0126, a MEK/ERK inhibitor receded pERK and c-Myc levels. In another experiment, U251 and 5310 cells treated with 10074-G5, c-Myc/Max inhibitor displayed reduction in pERK and c-Myc levels suggestive of a positive feedback loop between ERK/c-Myc/Max molecules. In the present study, we show that glioma cells exhibit abundant c-Myc expression and increased c-Myc/Max activity. In contrast, the glioma cells cocultured with hUCBSC demonstrated high Mad1 expression that competitively binds to Max to repress the c-Myc/Max mediated gene transcription. Our studies thus elucidate the potential role of hUCBSC in controlling glioma cell cycle progression and invasion by limiting Max binding to c-Myc, thus regulating the expression of glioma cell cycle and invasion associated molecules such as ERK, integrins via increased levels of Mad1 expression.

Abstract 77: Suppression of ERK1/2 with siRNA restores drug sensitivity in DU145 cells selected for resistance to AG2034

Abstract We examined the involvement of the extracellular signal regulated kinase (ERK) cascade (Ras/Raf/MEK/ERK) in the promotion of tumor cell growth, survival and the maintenance of ATP pools in DU145 prostate cancer cells selected for resistance to 4-[2-(2-amino-4-oxo-4,6,7,8-tetrahydro-3H-pyrimidino[5,4,6][1,4] thiazin-6-yl)-(S)-ethyl]-2,5-thienoylamino-L-glutamic acid (AG2034). The Ras/Raf/MEK/ERK cascade is a subfamily of the MAPK signal transduction pathway and it plays an important role in gene expressions, growth and differentiation of many cell types. The components of this pathway are often altered in tumor cells and conflicting evidence exists regarding its contribution to the development of resistance to several chemotherapeutic drugs. DU145 cells were selected over time for resistance to AG2034 by gradually decreasing hypoxanthine concentrations from 1.7 µM to zero in the continuous presence of 10 nM 5-methyl tetrahydrofolate and 50 nM AG2034. Since the inhibition of glycinamide ribonucleotide formyl-transferase blocks the incorporation of glycine into the purine ring, total cellular ATP was quantified by reverse-phase HPLC and [14C]-Glycine incorporation into ATP was determined by liquid scintillation counting of HPLC-isolated ATP fractions. Total and phosphorylated proteins were determined by western blotting. Quantitative RT-PCR was utilized to characterize mRNA expression levels before and after transient transfection studies with siRNA. The continuous treatment of cells with AG2034 is cytotoxic to parent DU145 cells and inhibits proliferation. However, in the resistance clones, drug presence did not prevent cell growth but rather, markedly reduces the growth rate in comparison to drug-naïve parent cells. While the treatment of parent cells with AG2034 for 24 h depletes total ATP levels, there was no significant difference in total ATP levels between parent cells and resistant clones. Although AG2034 inhibits [14C]-glycine incorporation into ATP in parent cells, this effect is abrogated by drug resistance. Acquired resistance increases ERK expression levels and phosphorylation status. It also increases upstream activators, NRas, BRaf and MEK. In addition, decreasing the expression of ERK by siRNA reduces steady state levels of total and phosphorylated ERK and results in a marked depletion of total ATP levels in resistant clones. In the parent cells however, ERK inhibition resulted in increased ERK phosphorylation but had no effect on total ATP pools. The inhibition of ERK re-sensitizes drug-resistant DU145 cells to AG2034 concomitant with a depletion of cellular ATP pools. These results demonstrate that DU145 cells selected for resistance to AG2034 require the sustenance of ERK1/2 phosphorylation for the maintenance of their ATP pools and suggest that the intrinsic activation of ERK signaling supports growth and survival in these AG2034-resistant clones. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 77.

The Role of Matrine and Mitogen-Ativated Protein Kinase/Extracellular Signal-Regulated Kinase Signal Transduction in the Inhibition of the Proliferation and Migration of Human Umbilical Veins Endothelial Cells Induced by Lung Cancer cells.

Matrine, one of the major alkaloid components of the traditional Chinese medicine Sophora roots, has a wide range of pharmacological effects including anti-inflammatory activities, growth inhibition and induction of cell differentiation and apoptosis. Motigen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) has found to be a crucial signaling pathway in endothelial cells. The aim of this study is to investigate the role of Matrine and MAPK/ERK signal transduction in the inhibition of the proliferation and migration of human umbilical veins endothelial cells (HUVECs) induced by lung cancer cells. HUVECs were cultured with A549CM. Mat or PD98059 (i.e PD), specific inhibitor of MAPK/ERK, was added into the A549CM. The proliferation of the HUVECs was measured by cell counting. The migration of the HUVECs was observed by wound healing assay. The expression levels of ERK and p-ERK protein were detected by Western Blot analysis. On 24 hours after intervention, the A549CM significantly stimulated the proliferation, migration and expression of p-ERK of HUVECs. Compared with the A549CM group, Mat significantly inhibited the proliferation, migration and p-ERK expression of HUVECs induced by A549CM. While PD only decreased the proliferation and p-ERK expression of HUVECs induced by A549CM. PD had no effect in the migration of HUVECs. The results demonstrated that Mat and PD98059 can effectively decrease proliferation and expression of p-ERK of HUVECs induced by A549CM. Furthermore Mat can also inhibit migration of HUVECs induced by A549CM that did not changed by PD98059. These data implied that suppressing MAPK/ERK signal transduction may play the crucial role in resisting lung cacinoma angiogenesis with Mat.

Comparison of Calcium and Silicate Cement and Mineral Trioxide Aggregate Biologic Effects and Bone Markers Expression in MG63 Cells

Bone cell (MG63) biocompatibility and bone marker expression were compared after calcium and silicate base cement (CS) and mineral trioxide aggregate (MTA) treatment. X-ray diffraction was used to identify material surface structure, and tetrazolium bromide colorimetric assay was used to evaluate the cell viability. The relative mitogen activation protein kinase expression was compared with Western blot, and bone marker expression was evaluated with reverse transcriptase polymerization chain reaction. The results showed that CS and MTA are similar chemical structures and biocompatible with MG63 cells. CS and MTA cements showed good MG63 cell proliferation by high phosphor extracellular signal-regulated kinase expression levels. CS and MTA cements showed the evident type I collagen, osteocalcin, alkaline phosphatase, bone sialoprotein, and osteopontin expression. Both MTA and CS cements are biocompatible and appear to have osetoconduction effects on bone cells.

Evaluation of Extracellular Signal Regulated Kinase Expression and Its Relation to Treatment of Hepatocellular Carcinoma

The aim of this study was to evaluate hepatocellular carcinoma (HCC) using a combination of extracellular signal regulated kinase (ERK) and other markers related to hepatocyte growth factor (HGF) in tumor tissue. Using specimens from 30 hepatocellular carcinoma patients operated on in our department from 2002 to 2003, we evaluated expression levels of HGF, c-Met, ERK, and cyclin D1 by Western blot. Expression levels of ERK and cyclin D1 proteins were significantly higher in patients with less well-differentiated type tumors by histologic examination or the presence of intrahepatic metastasis (IM). ERK expression in tumor tissue significantly correlated with both tumor size (p=0.0017, R(2)=0.355) and serum levels of HGF (p=0.0247, R(2)=0.218). Nontumor tissue level of cyclin D1 was significantly higher in patients with poor liver function (p=0.047). In patients with higher expression of ERK in tumor tissue compared with nontumor tissue, the histologic finding was more progressed; but a similar tendency was not observed for cyclin D1. In patients with overexpression of HGF and c-Met, the expression level of ERK was significantly higher, but cyclin D1 expression was not. The detected level of cyclin D1 was significantly higher in patients with overexpressed ERK in tumor tissue. Values of ERK and c-Met were correlated, and IM presence was detected more frequently in patients with high expression of ERK and c-Met protein. Even after complete removal of visible IM tumor, recurrence tumors were detected within 6 months in 7 patients with high expressions of both ERK and c-Met protein. Combination study of tumor expression of ERK might be useful to estimate the properties of hepatocellular carcinoma, especially for the presence of IM.

ACTIVATION OF EXTRACELLULAR SIGNAL-REGULATED KINASE IN HUMAN PROSTATE CANCER

To investigate the level of expression, activation state, and functional significance of extracellular signal regulated kinase (ERK) in prostate cancer. Human prostate tissue samples (n = 22) were obtained from patients undergoing radical prostatectomy for localized adenocarcinoma of the prostate (n = 16, age range 44 to 72 years) or normal prostate specimens (n = 6, age ranges 19 to 47 years) obtained from rapid autopsy. Immunoblots, in vitro kinase assays, and immunohistochemistry were used to determine the expression and activation state of ERK in human prostate cancer. Immunoblot and in vitro kinase assays demonstrated a 15-fold increase in ERK activation in prostate cancer specimens compared with normal human prostate tissue; however, ERK expression levels were only 1.3-fold higher in cancer. Immunohistochemical analysis demonstrated similar expression of ERK in cancer and normal tissues; however, phosphorylated ERK demonstrated greater intensity in the cancer specimens. Experiments conducted on a prostate cancer cell line demonstrated that EGF induced activation of ERK and cellular proliferation was partially inhibited by PD98059, a chemical inhibitor of the immediate upstream signaling component responsible of activation of ERK. Collectively, these data demonstrate a dramatic increase in ERK activation in prostate cancer compared with normal prostate tissue and suggest that inhibitors designed to target this signal transduction cascade might have therapeutic benefit in the treatment of prostate cancer.