应力缺失致骨质疏松大鼠成骨细胞细胞信号外调节激酶表达及通络生骨胶囊的影响

背景:长期卧床患者和航天员应力缺失导致骨质疏松现象的发生,通络生骨胶囊具有促进骨生成的作用,可能干预应力缺失状态下骨质疏松的发生。目的:观察应力缺失型骨质疏松动物细胞信号外调节激酶的变化以及通络生骨胶囊对其改善作用。方法:SD大鼠40只随机分为对照组、模型组、药物高、药物低剂量组,除正常组外以鼠尾悬吊法制备动物应力缺失模型,药物高、低剂量组将通络生骨胶囊按0.6,1.2g/kg剂量灌胃,1次/d,21d后,取腿骨,观察骨形态变化及成骨细胞细胞信号外调节激酶的表达水平。结果与结论:应力缺失导致骨质疏松,对细胞信号外调节激酶总量无显著影响,但显著降低其磷酸化蛋白表达;通络生骨胶囊可显著改善应力造成的骨质疏松状态,但药物高剂量组对磷酸化的细胞信号外调节激酶的表达影响不显著,药物低剂量组则还降低其表达。说明应力缺失通过降低细胞信号外调节激酶磷酸化水平导致骨质疏松,通络生骨胶囊不是通过影响细胞信号外调节激酶通路改善应力缺失导致的骨质疏松的。

TGF-β1对皮肤成纤维细胞的p-ERK表达的影响

目的探讨TGF-β1刺激后对皮肤成纤维细胞中磷酸化ERK表达的影响及相互关系。方法以原代培养人正常皮肤成纤维细胞为研究对象。细胞分2组:浓度组:10 ng/ml、5 ng/ml、1.0 ng/ml、0 ng/ml。时间组:给予10 ng/ml的TGF-β1刺激不同时间,分别在0、15、30、60、120 min的时间点提取蛋白。采用Western blotting法检测成纤维细胞中磷酸化ERK蛋白的表达变化。结果浓度组及时间组p-ERK蛋白表达与对照组相比均有差异(P<0.05),随着TGF-β1剂量增加和作用时间延长,其磷酸化ERK蛋白表达水平逐渐增强,在TGF-β1 5 ng/ml时p-ERK水平达作用最强,在作用60 min时p-ERK达高峰。结论随着TGF-β1浓度增加及作用时间延长,大剂量TGF-β1时可上调体外培养成纤维细胞内的ERK信号蛋白活性。TGF-β1诱导的成纤维细胞的p-ERK水平增高可能是依赖ERK通路激活的,但ERK通路与TGF-β/Smad通路存在交互作用的机制,目前还无定论。

N-methyl-D-aspartate receptors mediate diphosphorylation of extracellular signal-regulated kinases through Src family tyrosine kinases and Ca^2＋/calmodulin-dependent protein kinase Ⅱ in rat hippocampus after cerebral ischemia

Objective： Extracellular signal-regulated kinases （ERKs） can be activated by calcium signals. In this study, we investigated whether calcium-dependent kinases were involved in ERKs cascade activation after global cerebral ischemia. Methods Cerebral ischemia was induced by four-vessel occlusion, and the calcium-dependent proteins were detected by immunoblot. Results Lethal-simulated ischemia significantly resulted in ERKs activation in N-methyl-D-aspartate （NMDA） receptor-dependent manner, accompanying with differential upregulation of Src kinase and Ca^2＋/calmodulin-dependent protein kinase Ⅱ （CaMKⅡ） activities. With the inhibition of Src family tyrosine kinases or CaMKⅡ by administration of PP2 or KN62, the phosphorylation of ERKs was impaired dramatically during post-ischemia recovery. However, ischemic challenge also repressed ERKs activity when Src kinase was excessively activated. Conclusions Src family tyrosine kinases and CaMKⅡ might be involved in the activation of ERKs mediated by NMDA receptor in response to acute ischemic stimuli in vivo, but the intense activation of Src kinase resulted from ischemia may play a reverse role in the ERKs cascade.

Involvement of MAPK/ERK kinase-ERK pathway in exogenous bFGF-induced Egr-1 binding activity enhancement in anoxia-reoxygenation injured astrocytes

Objective Intravenous administration of basic fibroblast growth factor （bFGF） is effective to reduce the volume of cerebral infract due to ischemia. This study was designed to investigate the molecular mechanism, especially the signal transduction pathways, involved in this protective role of bFGF. Methods Anoxia-reoxygenation treated atrocytes were used to study the role of mitogen-activated protein kinase/extracellular signal-regulated kinase kinase （MAPK/ERK kinase, MEK）-ERK signaling pathway after exogenous bFGF administration by Western blot. Electrophoretic mobile shift assay was used to detect the binding activity of early growth response factor-1 （Egr-1）, an important transcription factor for endogenous bFGF. Results bFGF could protect some signal transduction proteins from the oxygen-derived free radicals induced degradation. ERK1/2 was activated and involved in Egr-1 binding activity enhancement induced by exogenous bFGF. Conclusion MEK-ERK MAPK cascade may be an important signal transduction pathway contributed to bFGF induced enhancement of Egr-1 binding activity in anoxia-reoxygenation injured astrocytes.

Components of the mitogen-activated protein kinase cascade are activated in hepatic cells by Echinococcus multilocularis metacestode

AIM： To explore the effect of Echinococcusmultilocularis on the activation of mitogen-activated protein kinase （MAPK） signaling pathways and on livercell proliferation.METHODS： Changes in the phosphorylation of MAPKs and proliferating cell nuclear antigen （PCNA）expression were measured in the liver of patients withalveolar echinococcosis （AE）. MAPKs, MEK1/2 [MAPK/extracellular signal-regulated protein kinase （ERK）kinase] and ribosomal S6 kinase （RSK） phosphorylationwere detected in primary cultures of rat hepatocytesin contact in vitro with （1） E. multilocu/aris vesicle fluid（EmF）, （2）E. multilocularis-conditioned medium （EmCM）.RESULTS： In the liver of AE patients, ERK 1/2 andp38 MAPK were activated and PCNA expression wasincreased, especially in the vicinity of the metacestode.Upon exposure to EmF, p38, c-Jun N-terminal kinase（JNK） and ERK1/2 were also activated in hepatocytesin vitro, as well as MEK1/2 and RSK, in the absenceof any toxic effect. Upon exposure to EmCM, only JNKwas up-regulated.CONCLUSION： Previous studies have demonstratedan influence of the host on the MAPK cascade inE. multilocularis. Our data suggest that the reverse,i.e. parasite-derived signals efficiently acting onMAPK signaling pathways in host liver ceils, is actuallyoperating.

Astragalus mongholicus polysaccharide inhibits lipopolysaccharide-induced production of TNF-α and interleukin-8

AIM： To explore the effect of Astraga/us mongholicus polysaccharide （APS） on gene expression and mitogenactivated protein kinase （MAPK） transcriptional activity in intestinal epithelial cells （IEC）. METHODS： IEC were divided into control group, lipopolysaccharide （LPS） group, LPS＋ 50 μg/mL APS group, LPS＋ 100 μg/mL APS group, LPS＋ 200 μg/mL APS group, and LPS＋ 500 μg/mL APS group. Levels of mRNAs in LPS-induced inflammatory factors, tumor necrosis factor （TNF）-α and interleukin （IL）-8, were measured by reverse transcription-polymerase chain reaction. MAPK protein level was measured by Western blotting. RESULTS： The levels of TNF-α and IL-8 mRNAs were significantly higher in IEC with LPS-induced damage than in control cells. APS significantly abrogated the LPS-induced expression of the TNF-α and IL-8 genes. APS did not block the activation of extracellular signal- regulated kinase or c Jun amino-terminal kinase, but inhibited the activation of p38, suggesting that APS inhibits LPS-induced production of TNF-α and IL-8 mRNAs, possibly by suppressing the p38 signaling pathway.CONCLUSION： APS-modulated bacterial productmediated p38 signaling represents an attractive strategy for prevention and treatment of intestinal inflammation.

Down-regulation of extracellular signal-regulated kinase 1/2 activity in P-glycoprotein-mediated multidrug resistant hepatocellular carcinoma cells

AIM： To study the expression and phosphorylation of extracellular signal-regulated kinase （ERK） i and ERK2 in multidrug resistant （MDR） hepatocellular carcinoma （HCC） cells.METHODS： MDR HCC cell lines, HepG2/adriamycin （ADM） and SMMC7721/ADM, were developed by exposing parental cells to stepwise increasing concentrations of ADM. MTT assay was used to determine drug sensitivity. Flow cytometry was employed to analyze cell cycle distribution and measure cell P-glycoprotein （P-gp） and multidrug resistant protein 1 （MRP1） expression levels. ERK1 and ERK2 mRNA expression lev-ls were measured by quantitative real-time PCR （QRTPCR）. Expression and phosphorylation of ERK1 and ERK2 were analyzed by Western blot.RESULTS： MTT assay showed that HepG2/ADM andSMMC7721/ADM were resistant not only to ADM, but also to multiple anticancer drugs. The P-gp expression was over 10-fold higher in HepG2/ADM cells than in HepG2 cells （8.92% ±0.22% vs 0.88% ± 0.05%, P 〈 0.001） and over 4-fold higher in SMMC7721/ADM cells than in SMMC7721 cells （7.37% ± 0.26% vs 1.74% ± 0.25%, P 〈 0.001）. However, the MRP1 expression was not significantly higher in HepG2/ADM and SMMC7721/ADM cells than in parental cells. In addition, the percentage of MDR HepG2/ADM and SMMC7721/ADM cells was significantly decreased in the G0/G1 phase and increased in the the S phase or G2/M phase. QRT-PCR analysis demonstrated that the ERK1 and ERK2 mRNA expression increased apparently in HepG2/ADM cells and decreased significantly in SMMC7721/ADM cells. Compared with the expression of parental cells, ERK1 and ERK2 protein expressions were markedly decreased in SMMC7721/ADM cells. However, ERK2 protein expression was markedly increased while ERK1 protein expression had no significant change in HepG2/ADM cells. Phosphorylation of ERK1 and ERK2 was markedly decreased in both HepG2/ADM and SMMC7721/ADM MDR cells.CONCLUSION： ERK1 and ERK2 activities are downregulated in P-gp-mediated MDR HCC cells. ERK1 or ERK2 might be a potential drug target for circumventing MDR HCC cells,

Suppression of esophageal cancer cell growth using curcumin,(-)-epigallocatechin-3-gallate and lovastatin

AIM:To determine the effects of curcumin,(-)-epigallocatechin-3-gallate (EGCG),lovastatin,and their combinations on inhibition of esophageal cancer.METHODS:Esophageal cancer TE-8 and SKGT-4 cell lines were subjected to cell viability methyl thiazolyl tetrazolium and tumor cell invasion assays in vitro and tumor formation and growth in nude mouse xenografts with or without curcumin,EGCG and lovastatin treatment.Gene expression was detected using immunohistochemistry and Western blotting in tumor cell lines,tumor xenografts and human esophageal cancer tissues,respectively.RESULTS:These drugs individually or in combinations significantly reduced the viability and invasion capacity of esophageal cancer cells in vitro.Molecularly,these three agents reduced the expression of phosphorylated extracellular-signal-regulated kinases (Erk1/2),c-Jun and cyclooxygenase-2 (COX-2),but activated caspase 3 in esophageal cancer cells.The nude mouse xenograft assay showed that EGCG and the combinations of curcumin,EGCG and lovastatin suppressed esophageal cancer cell growth and reduced the expression of Ki67,phosphorylated Erk1/2 and COX-2.The expression of phosphorylated Erk1/2 and COX-2 in esophageal cancer tissue specimens was also analyzed using immunohistochemistry.The data demonstrated that 77 of 156 (49.4%) tumors expressed phosphorylated Erk1/2 and that 121 of 156 (77.6%) esophageal cancers expressed COX-2 protein.In particular,phosphorylated Erk1/2 was expressed in 23 of 50 (46%) cases of esophageal squamous cell carcinoma (SCC) and in 54 of 106 (50.9%) cases of adenocarcinoma,while COX-2 was expressed in 39 of 50 (78%) esophageal SCC and in 82 of 106 (77.4%) esophageal adenocarcinoma.CONCLUSION:The combinations of curcumin,EGCG and lovastatin were able to suppress esophageal cancer cell growth in vitro and in nude mouse xenografts,these drugs also inhibited phosphorylated Erk1/2,c-Jun and COX-2 expression.

MUC5AC/β-catenin expression and KRAS gene alteration in laterally spreading colorectal tumors

AIM： To clarify differences in mucin phenotype, prolif- erative activity and oncogenetic alteration among sub- types of colorectal laterally spreading tumor （LST）. METHODS： LSTs, defined as superficial elevated lesions greater than 10 mm in diameter with a low vertical axis, were macroscopically classified into two subtypes： （1） a granular type （Gr-LST） composed of superficially spread- ing aggregates of nodules forming a fiat-based lesion with a granulonodular and uneven surface; and （2） a non-granular type （NGr-LST） with a flat smooth surface and an absence of granulonodular formation. A total of 69 LSTs, comprising 36 Gr-LSTs and 33 NGr-LSTs, were immunohistochemically stained with MUC2, MUC5AC, MUC6, CD10 （markers of gastrointestinal cell lineage）, p53, 13-catenin and Ki-67 antibodies, and examined for alteration in exon 1 of v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog （KRAS） and exon 15 of v-raf murine sarcoma viral oncogene homologue B1 （BRAF） by poly- merase chain reaction followed by direct sequencing. RESULTS： Histologically, 15 Gr-LST samples were ad- enomas with low-grade dysplasia （LGD）, 12 were high- grade dysplasia （HGD） and 9 were adenocarcinomas invading the submucosa （INV）, while 12 NGr-LSTs demonstrated LGD, 14 HGD and 7 INV. In the proximal colon, MUC5AC expression was significantly higher in the Gr-type than the NGr-type. MUC6 was expressed only in NGr-LST. MUC2 or CD10 did not differ. P53 ex- pression demonstrated a significant stepwise increment in progression through LGD-HGD-INV with both types of LST. Nuclear β-catenin expression was significantly higher in the NGr-type. Ki-67 expression was signifi- cantly higher in the Gr-type in the lower one third zone of the tumor. In proximal, but not distal colon tumors, the incidence of KRAS provided mutation was signifi- cantly higher in the Gr-type harboring a specific muta- tional pattern （G12V）. BRAF mutations （V600E） were detected only in two Gr-LSTs. CONCLUSION： The two subtypes of LST, especially in the proximal colon, have differing phenotypes of gastrointestinal cell lineage, proliferation and activa- tion of Wnt/β-catenin or RAS/RAF/extracellular signal- regulated kinase signaling.

Baicalin inhibits PDGF-BB-stimulated vascular smooth muscle cell proliferation through suppressing PDGFRβ-ERK signaling and increase in p27 accumulation and prevents injury-induced neointimal hyperplasia

The increased proliferation and migration of vascular smooth muscle cells （VSMCs） are key events in the development of atherosclerotic lesions. Baicalin, an herb-derived flavonoid compound, has been previously shown to induce apoptosis and growth inhibition in cancer cells through multiple pathways. However, the potential role of baicalin in regulation of VSMC proliferation and prevention of cardiovascular diseases remains unexplored. In this study, we show that pretreatment with baicalin has a dose-dependent inhibitory effect on PDGF-BB-stimulated VSMC pro- liferation, accompanied with the reduction of proliferating cell nuclear antigen （PCNA） expression. We also show that baicalin-induced growth inhibition is associated with a decrease in cyclin E-CDK2 activation and increase in p27 level in PDGF-stimulated VSMCs, which appears to be at least partly mediated by blockade of PDGF recep- tor [~ （PDGFR~）-extracellular signal-regulated kinase 1/2 （ERK1/2） signaling. In addition, baicalin was also found to inhibit adhesion molecule expression and cell migration induced by PDGF-BB in VSMCs. Furthermore, using an animal carotid arterial balloon-injury model, we found that baicalin significantly inhibited neointimal hyperplasia. Taken together, our results reveal a novel function of baicalin in inducing growth arrest of PDGF-stimulated VSMCs and suppressing neointimal hyperplasia after balloon injury, and suggest that the underlying mechanism involves the inhibition of cyclin E-CDK2 activation and the increase in p27 accumulation via blockade of the PDGFR^-ERK1/2 signaling cascade.

Sorafenib inhibits growth and metastasis of hepatocellular carcinoma by blocking STAT3

AIM: To investigate the inhibitory role and the underlying mechanisms of sorafenib on signal transducer and activator of transcription 3 (STAT3) activity in hepatocellular carcinoma (HCC).METHODS: Human and rat HCC cell lines were treated with sorafenib. Proliferation and STAT3 dephosphorylation were assessed. Potential molecular mechanisms of STAT3 pathway inhibition by sorafenib were evaluated. In vivo antitumor action and STAT3 inhibition were investigated in an immunocompetent orthotopic rat HCC model.RESULTS: Sorafenib decreased STAT3 phosphorylationat the tyrosine and serine residues (Y705 and S727), but did not affect Janus kinase 2 (JAK2) and phosphatase shatterproof 2 (SHP2), which is associated with growth inhibition in HCC cells. Dephosphorylation of S727 was associated with attenuated extracellular signal-regulated kinase (ERK) phosphorylation, similar to the effects of a mitogen-activated protein kinase (MEK) inhibitor U0126, suggesting that sorafenib induced S727 dephosphorylation by inhibiting MEK/ERK signaling. Meanwhile, sorafenib could also inhibit Akt phosphorylation, and both the phosphatidylinositol-3-kinase (PI3K) inhibitor LY294002 and Akt knockdown resulted in Y705 dephosphorylation, indicating that Y705 dephosphorylation by sorafenib was mediated by inhibiting the PI3K/Akt pathway. Finally, in the rat HCC model, sorafenib signifi cantly inhibited STAT3 activity, reducing tumor growth and metastasis.CONCLUSION: Sorafenib inhibits growth and metastasis of HCC in part by blocking the MEK/ERK/STAT3 and PI3K/Akt/STAT3 signaling pathways, but independent of JAK2 and SHP2 activation.

Insulin-like growth factor binding protein-5 influences pancreatic cancer cell growth

AIM： To investigate the functional significance of insulin-like growth factor binding protein-5 （IGFBP-5） overexpression in pancreatic cancer （PaC）.METHODS： The effects of IGFBP-5 on cell growth were assessed by stable transfection of BxPC-3 and PANC-1 cell lines and measuring cell number and DNA synthesis. Alterations in the cell cycle were assessed by flow cytometry and immunoblot analyses. Changes in cell survival and signal transduction were evaluated after mitogen and phosphatidylinositol activated protein kinase 3-kinase （PI3K） inhibitor treatment.RESULTS： After serum deprivation, IGFBP-5 expression increased both cell number and DNA synthesis in BxPC-3 cells, but reduced cell number in PANC-1 cells. Consistent with this observation, cell cycle analysis of IGFBP-5-expressing cells revealed accelerated cell cycle progression in BxPC-3 and G2/M arrest of PANC-1 cells. Signal transduction analysis revealed that Akt activation was increased in BxPC-3, but reduced in PANC-1 cells that express IGFBP-5. Inhibition of PI3K with LY294002 suppressed extracellular signal-regulated kinase-1 and -2 （ERK1/2） activation in BxPC-3, but enhanced ERK1/2 activation in PANC-1 cells that express IGFBP-5. When MEK1/2 was blocked, Akt activation remained elevated in IGFBP-5 expressing PaC cells; however, inhibition of PI3K or MEK1/2 abrogated IGFBP-5-mediated cell survival.CONCLUSION： These results indicate that IGFBP-5 expression affects the cell cycle and survival signal pathways and thus it may be an important mediator of PaC cell growth.

Differential expression of Bcl-2 and Bax during gastric ischemia-reperfusion of rats

AIM: To investigate expression of Bcl-2 and Bax in gastric ischemia-reperfusion (GI-R) and involvement of extracellular signal-regulated kinase (ERK) 1/2 activation. METHODS: The GI-R model was established by ligature of the celiac artery for 30 min and reperfusion in SpragueDawley rats. Rats were assigned to groups in accordance with their evaluation period: control, 0, 0.5, 1, 3, 6, 24, 48, and 72 h. Expression and distribution of Bcl-2 and Bax proteins were analyzed by immunohistochemistry and western blotting in gastric tissue samples after sacrifice. RESULTS: Compared with controls, the percentage of positive cells and protein levels of Bcl-2 decreased inthe early phases of reperfusion, reached its minimum at 1 h (P < 0.05); it then increased, reaching its peak at 24 h of reperfusion (P < 0.05). The pattern of Bax expression was opposite to that of Bcl-2. Bax expression increased after reperfusion, with its peak at 1 h of reperfusion (P < 0.05), and then it decreased gradually to a minimum at 24 h after reperfusion (P < 0.05). On the other hand, inhibition of activation of ERK1/2 induced by PD98059, a specific upstream MEK inhibitor, had significant effects on Bcl-2 and Bax in GI-R. Compared with GI-R treatment only at 3 h of reperfusion, PD98059 reduced the number of Bcl-2 positive cells (0.58% of R3h group, P < 0.05) and Bcl-2 protein level (74% of R3h group, P < 0.05) but increased the number of Bax-positive cells (1.33-fold vs R3h group, P < 0.05) and Bax protein level (1.35-fold of R3h group, P < 0.05). CONCLUSION: These results indicated that the Bcl-2 and Bax played a pivotal role in the gastric mucosal I-R injury and repair by activation of ERK1/2.

Down-regulation of HIV-1 Infection by Inhibition of the MAPK Signaling Pathway

The human immunodeficiency virus type 1 （HIV-1） can interact with and exploit the host cellular machinery to replicate and propagate itself. Numerous studies have shown that the Mitogen-activated protein kinase （MAPK） signal pathway can positively regulate the replication of HIV-1, but exactly how each MAPK pathway affects HIV-1 infection and replication is not understood. In this study, we used the Extracellular signal-regulated kinase （ERK） pathway inhibitor, PD98059, the Jun N-terminal kinase （JNK） pathway inhibitor, SP600125, and the p38 pathway inhibitor, SB203580, to investigate the roles of these pathways in HIV-1 replication. We found that application of PD98059 results in a strong VSV-G pseudotyped HIV-1NL4-3 luciferase reporter virus and HIV-1NL4-3 virus inhibition activity. In addition, SB203580 and SP600125 also elicited marked VSV-G pseudotyped HIV-INL4-3 luciferase reporter virus inhibition activity but no HIV-1NL4-3 virus inhibition activity. We also found that SB203580 and SP600125 can enhance the HIV-1 inhibition activity of PD98059 when cells were treated with all three MAPK pathway inhibitors in combination. Finally, we show that HIV-1 virus inhibition activity of the MAPK pathway inhibitors was the result of the negative regulation of HIV-1 LTR promoter activity.

Regulation of Hepatitis C Virus Replication and Gene Expression by the MAPK-ERK Pathway

The mitogen activated protein kinases-extracellular signal regulated kinases （MAPK-ERK） pathway is involved in regulation of multiple cellular processes including the cell cycle. In the present study using a Huh7 cell line Conl with an HCV replicon, we have shown that the MAPK-ERK pathway plays a significant role in the modulation of HCV replication and protein expression and might influence IFN-a signalling. Epithelial growth factor （EGF） was able to stimulate ERK activation and decreased HCV RNA load while a MAPK-ERK pathway inhibitor U0126 led to an elevated HCV RNA load and higher NS5A protein amounts in Conl cells. It could be further demonstrated that the inhibition of the MAPK-ERK pathway facilitated the translation directed by the HCV internal ribosome entry site. Consistently, a U0126 treatment enhanced activity of the HCV reporter replicon in transient transfeetion assays. Thus, the MAPK-ERK pathway plays an important role in the regulation of HCV gene expression and replication. In addition, cyclin-dependent kinases （CDKs） downstream of ERK may also be involved in the modulation of HCV replication since roscovitine, an inhibitor of CDKs had a similar effect to that of U0126. Modulation of the cell cycle progression by cell cycle inhibitor or RNAi resulted consistently in changes of HCV RNA levels. Further, the replication of HCV replicon in Conl cells was inhibited by IFN-~z. The inhibitory effect of IFN-CZ could be partly reversed by pre-incubation of Con-1 cells with inhibitors of the MAPK-ERK pathway and CDKs. It could be shown that the MAPK-ERK inhibitors are able to partially modulate the expression of interferon-stimulated genes.

Study on the Expression and Significance of TGF-β1, p-ERK1/2and K-ras in Colorectal Cancer Using Tissue Microarray Technique

OBJECTIVE This study aimed to explore the expression and significance of transforming growth factor β1（TGF-β1）,extracellular signal-regulated kinases 1/2 （ERK1/2）, and K-ras in colorectal cancer （CRC） using tissue microarray technology.METHODS The expressions of TGF-β1, ERK1/2, and K-ras in colon cancer cells taken from the specimens of 92 CRC patients （stage Ⅰ： 16 cases, stage Ⅱ： 28 cases, stage Ⅲ： 24 cases, and stage Ⅳ：24 cases） were analyzed using tissue microarray technology and immunohistochemistry, and compared with those of 20 normal colon tissue samples.RESULTS High immunoreactive scores （IRS） of TGF-β1,p-ERK1/2, and K-ras protein in CRC were obtained, which were 66.3% （61/92）, 59.8% （55/92）, and 48.9% （45/92）, respectively, and those in normal epithelial cells of colon were 10% （2/20）, 20% （4/20）, and 30% （6/20）, respectively （P 〈 0.05）. The expressions of TGF-β1 and ERK1/2 in CRC at stage Ⅰwere 37.5% and 31.3%,respectively, and those in CRC at stage Ⅳ were 83.3% and79.3%, respectively, with statistically significant differences. No significant relationship was found between K-ras expression and tumor stages （P〉0.05）.CONCLUSION High level expressions of TGF-β1 and ERK1/2 are closely related to the clinical stages of colon cancer and crosstalk may exist between the 2 signal pathways.

Activation of extracellular signal-regulated kinase in the anterior cingulate cortex contributes to the induction of long-term potentiation in rats

Objective To explore the role of the extracellular signal-regulated kinase （ERK）/cAMP response element binding protein （CREB） pathway in the induction of long-term potentiation （LTP） in the anterior cingulate cortex （ACC） that may be implicated in pain-related negative emotion. Methods LTP of field potential was recorded in ACC slice and the expressions of phospho-ERK （pERK） and phospho-CREB （pCREB） were examined using immunohistochemistry method. Results LTP could be induced stably in ACC slice by high frequency stimulation （2-train, 100 Hz, 1 s）, while APv （an antagonist of NMDA receptor） could block the induction of LTP in the ACC, indicating that LTP in this experiment was NMDA receptor-dependent. Bath application of PD98059 （50 μmol/L）, a selective MEK inhibitor, at 30 min before tetanic stimulation could completely block the induction of LTP. Moreover, the protein level of pERK in the ACC was transiently increased after LTP induction, starting at 5 rain and returning to basal at 1 h after tetanic stimulation. The protein level of pCREB was also increased after LTP induction. The up-regulation in pERK and pCREB expressions could be blocked by pretreatment of PD98059. Double immunostaining showed that after LTP induction, most pERK was co-localized with pCREB. Conclusion NMDA receptor and ERK-CREB pathway are necessary for the induction of LTP in rat ACC and may play important roles in pain emotion.

Endostatin inhibits fibrosis by modulating the PDGFR/ERK signal pathway:an in vitro study

Accumulating evidence indicates that endostatin inhibits fibrosis. However, the mechanism is yet to be clarified. The aim of this study is to evaluate the effect of endostatin on platelet-derived growth factor-BB （PDGF-BB）- or transforming growth factor β1 （TGF-β1）-induced fibrosis in cultured human skin fibroblasts, and to further examine the molecular mechanisms involved. Human dermal flbroblasts were cultured in Dulbecco＇s modified Eagle＇s medium （DMEM） and serum-starved for 48 h before treatment. Cells were grouped as follows： ＂PDGF-BB＂, ＂PDGF-BB＋ endostatin＂, ＂TGF-β1＂, ＂TGF-β1＋endostatin＂, ＂endostatin＂, and ＂blank control＂. The fibroblasts were stimulated with either TGF-β1 or PDGF-BB for 72 h in order to set up the fibrosis model in vitro. The cells were co-cultured with either TGF-β1 or PDGF-BB and endostatin and were used to check the inhibiting effect of endostatin. A blank control group and an endostatin group were used as negative control groups. The biomarkers of fibrosis, including the expression of collagen I, hydrroxyproline, and α-smooth muscle actin （a-SMA）, were evaluated using an enzyme-linked immune- sorbent assay （ELISA） and Western blot. The expression of phosphorylated PDGF receptor β （p-PDGFRβ）, PDGFRβ, phosphorylated extracellular signal-regulated kinase （p-ERK）, and ERK was detected using Western blot and im- munofiuorescent staining was used to explore the mechanisms. Both PDGF-BB and TGF-β1 significantly up-regulated the expression of collagen I, hydroxyproline, and a-SMA. Endostatin significantly attenuated both the PDGF-BB- and TGF-β1-induced over-expression of collagen I, hydroxyproline, and a-SMA. PDGF-BB and TGF-β1 both promoted the expression of PDGFR, ERK, and p-ERK. Endostatin inhibited the expression of PDGFR and p-ERK but did not affect the expression of total ERK. Endostatin inhibited hypertrophic scar by modulating the PDGFRI3/ERK pathway. En- dostatin could be a promising multi-target drug in future fibrosis therapy.

Effects of moxibustion pretreatment on extracellular signal-regulated kinase signaling transduction pathway in the gastric tissues of rats with gastric mucosal damage

Objective： To observe the effects of moxibustion pretreatment on the protein expressions of epidermal growth factor receptor （EGFR）, phosphorylation extracellular signal-regulated kinase I/2 （p-ERKI/2） and activated protein-1 （AP-2）, the key factors of extracellular signal-regulated kinase signaling transduction pathway in gastric tissue of rats with stress-induced gastric mucosal damage, and to discuss the mechanisms of moxibustion therapy in promoting the restoration of damaged gastric mucosa. Methods： Thirty Sprague-Dawley （SD） rats were randomly divided into a normal group, a model group, and a moxibustion group using the random digits table, 10 in each group. Except the rats in the normal group, rats in the other two groups were used to make stress-induced gastric mucosal damage model using restraint and cold stress. Before modeling, rats in the moxibustion group were alternately treated with moxibustion a/t Zusanli （ST 36） and Zhongwan （CV 12）, or Pishu （BL 20） and Weishu （BL 22）, once a day, for a total of 8 d. Histolo^cal changes of gastric mucosa were observed under the light microscopy, the expression of gastric tissue p-ERKI/2 was detected by immunohistochemistry assay, and the protein levels of EGFR and AP-I were measured by Western blots. Results： Compared with rats in the normal group, gastric mucosal damage was more serious, and protein expressions of gastric tissue EGFR, p-ERK1/2 and AP-1 increased in the model group （P〈0.01, P〈O.05, P〈0.05）. Compared with rats in the model group, gastric mucosal damage was milder, and protein expressions of gastric tissue EGFR, p-ERK1/2 and AP-1 increased in the moxibustion group （all P〈0.01）. Conclusion： Moxibustion at Zusanli （ST 36）, Zhongwan （CV 12）, Pishu （BL 20） and Weishu （BL 21） could increase EGFR, p-ERK1/2 and AP-1 expression levels in gastric tissue of stress-induced gastric mucosal damage rats, maintain the information transfer function of ERK signaling transduction pathway, and promote restoration of gastric mucosal damage.

Busuishengxue ranules mediate their effects upon non-severe aplastic anemia via mitogen-activated protein kinase/extracellular signal-regulated kinase pathway

OBJECTIVE:To observe the clinical efficacy of Busuishengxue granules on non-severe aplastic anemia(NSAA)and investigate its effect on the mitogen-activated protein kinase/extracellular signal-regulated kinase(MAPK/ERK)pathway.METHODS:Sixty NSAA patients were divided equally into two groups.Subjects in the experimental group were treated with Busuishengxue granules,and the control group with Zaizaoshengxue tablets.The treatment course was 6 months and cu-rative efficacy was compared between the two groups as well as with 10 healthy individuals.Flow cytometry(FCM)was used to detect the intracellular concentration of Ca2+([Ca2+]i).Western blotting was employed to detect the expression of enzymes in the MAPK/ERK pathway.RESULTS:The efficacy of Busuishengxue granules was significantly better than that of Zaizaoshengxue tablets(P<0.05).Before treatment,expression of JNK,phospho-ERK 1/2 and p-JNK was higher,and[Ca2+]i higher,than that of the control group(P<0.05).After treatment with Busuishengxue granules,expression of all enzymes related to signal transduction pathways in the blood cells of NSSA patients were altered to different degrees.CONCLUSION:Busuishengxue granules had a better effect with regard to improving symptom scores,increasing the number of blood leukocytes,and increasing hemoglobin levels than Zaizaoshengxue tablets,and they differed slightly in terms of increasing the number of platelets.