PD98059 抑制aFGF诱导的人膀胱癌细胞株EJ细胞增殖

目的探讨细胞外信号调节激酶(ERK)激酶MEK抑制剂PD98059对酸性成纤维细胞生长因子(aFGF)诱导的人膀胱癌细胞株EJ细胞增殖的抑制作用。方法以不同浓度的aFGF和PD98059作用EJ细胞,通过细胞计数法、MTT比色法观察PD98059对细胞增殖的抑制作用;流式细胞仪测定细胞各周期细胞百分数的变化;利用[γ3-2P]ATP掺入外源性底物的方法,液体闪烁测定ERK活性的变化。结果aFGF使EJ细胞株增殖比明显增加,而PD98059使EJ细胞株增殖比明显下降,在一定浓度范围内,其程度均随浓度增高而增强。EJ细胞受到aFGF刺激后,由G0+G1期进入S和G2+M期的细胞明显增多,在PD98059的作用下,由G0+G1期进入S和G2+M期的细胞明显减少,并在一定浓度范围内成剂量依赖性,与对照组比较差异显著(P<0.05);随着aFGF浓度的增加,EJ细胞ERK活性增高,PD98059抑制细胞内ERK活性,与PD98059浓度呈剂量依赖效应。结论PD98059对aFGF引起的EJ细胞增殖具有抑制作用,aFGF可能通过激活Ras-Raf-ERK信号转导途径来调控EJ细胞增殖,PD98059可有效阻滞此传导途径。     

AM及其抑制剂对人卵巢癌细胞株(CAOV3)PKB活性的影响

目的探讨肾上腺髓质素(Adrenom edullin,AM)及AM受体阻断剂(AM22-52)对人卵巢癌细胞株CAOV3蛋白激酶B(PKB)活性的影响。方法以不同浓度的AM和AM22-52诱导CAOV3细胞,利用Western印迹方法,测定PKB活性的变化。结果AM和AM受体阻断剂AM22-52对t-PKB(total-PKB)的表达量均无明显影响;随着AM浓度(1×10-9～1×10-6mol/L)的增加,CAOV3细胞p-PKB活性随之升高,呈剂量依赖关系;AM受体阻断剂AM22-52(1×10-9～1×10-6mol/L)抑制CAOV3细胞内p-PKB活性,也呈剂量依赖效应。结论AM激活CAOV3细胞内的PKB信号通路,AM22-52可有效阻滞此传导途径,为卵巢癌的生物治疗提供新的思路。     

藏红花素对人脐静脉内皮细胞增殖及细胞外调节蛋白激酶信号通路的影响

目的观察藏红花素(crocin)对人脐静脉内皮细胞(HUVECs)体外增殖、细胞外调节蛋白激酶(ERK)1/2表达及活性的影响。方法用藏红花素及MAPK/ERK激酶(MEK)抑制剂PD98059分别处理HUVECs,Ed U细胞增殖法检测细胞体外增殖活力,Western blotting法检测crocin对磷酸化细胞外调节蛋白激酶1/2(ERK1/2)和总ERK1/2表达的影响,激光扫描共焦显微镜检测细胞内Ca~(2+)浓度。结果在1μmol/L和10μmol/L浓度水平,藏红花素可明显促进细胞的增殖能力,提高磷酸化ERK1/2和总ERK1/2蛋白的表达水平,并增加细胞内Ca~(2+)浓度;给予MEK抑制剂PD98059后,细胞的增殖能力下降,磷酸化ERK1/2和总ERK1/2的表达减弱,细胞内Ca~(2+)浓度降低。结论藏红花素通过活化ERK1/2信号途径,提高细胞内Ca~(2+)浓度,促进人脐静脉内皮细胞的体外增殖能力。     

bFGF对卵巢癌CAOV3细胞Bcl-2、Bcl-xl、Bax、Bad表达的影响

目的研究bFGF调控卵巢癌CAOV3凋亡的信号通路及对Bcl-2、Bcl-xl、Bax、Bad表达的影响。方法无血清饥饿诱导细胞凋亡。分为饥饿对照、bFGF、bFGF PD98059、bFGF Wortmannin组。流式细胞术、DNA Ladder检测细胞凋亡;Western印迹法检测ERK、PKB、Bad活性以及Bcl-2、Bax表达,RT- PCR检测Bcl-2、Bcl-xl mRNA变化。结果bFGF促进p-ERK、p-PKB、p-Bad、Bcl-2表达,抑制Bax表达及饥饿诱导的细胞凋亡。激酶抑制剂PD98059可抑制bFGF对ERK、Bcl-2、Bax的调节作用,Wortmannin可抑制bFGF对PKB、Bad、Bax的调控作用,二者均可阻断bFGF对凋亡的抑制作用。bFGF对Bcl-xl表达无影响。结论bFGF可能通过激活MEK/ERK、P13K/PKB信号途径通路调节Bcl-2、Bax、Bad表达,抑制饥饿诱导的卵巢癌CAOV3细胞凋亡。     

PKC和ERK在大鼠心肌缺氧预处理延迟保护机制中的作用

目的:探讨蛋白激酶C(PKC)和细胞外信号调节激酶(ERK)在大鼠缺氧预处理(APC)延迟保护机制中的作用及二者之间的相互关系。方法:建立培养乳鼠心肌细胞缺氧/复氧(A/R)损伤和APC延迟心肌保护模型,用PKC兴奋剂(PMA)模拟预处理延迟保护模型,分别应用PKC和ERK抑制剂干预模型,并在各组相当于预处理后10min取材检测ERK活性。以实验终点检测培养基中乳酸脱氢酶(LDH)活性、细胞存活率、心肌细胞超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量作为心肌细胞损伤的指标。结果:预处理组心肌细胞存活率和SOD含量均显著高于A/R组(P＜0.05),培养液内LDH漏出和心肌细胞内MDA含量显著低于A/R组(P＜0.05),ERK活性显著高于A/R组(P＜0.05),应用PMA激活PKC可以模拟预处理的保护作用;ERK阻滞剂PD98059消除了缺氧和PMA的预处理保护作用,并抑制了预处理后的ERK活性的升高;PKC抑制剂多粘菌素B对APC引起的ERK激活及延迟保护作用无明显影响,但可抑制PMA诱导的保护现象。结论:ERK活化可能是APC延迟保护机制中的必须信号转导途径;PKC活化可以通过激活ERK启动缺氧预处理的延迟保护机制。     

p38MAPK参与千金藤素诱导的心肌细胞凋亡

目的: 探讨千金藤素(CEP)致Sprague-Dawley(SD)乳大鼠心肌细胞的凋亡作用及其信号途径。方法: 应用MTT法检测千金藤素对心肌细胞活性的抑制作用;利用Hoechst 33342染色及Western blotting方法检测凋亡相关信号分子caspase-3,观察CEP致心肌细胞凋亡的作用;采用Western blotting法观测 CEP对有丝分裂原活化蛋白激酶(MAPKs)家族3个主要信号分子c-Jun氨基端激酶(JNK)、细胞外信号调节激酶(ERK)、p38 MAPK磷酸化水平的影响,并利用ERK和p38 MAPK的特异性抑制剂,分别验证两种分子所介导的信号通路在CEP致心肌细胞凋亡中的作用。结果: (1)CEP能够剂量依赖和时间依赖地抑制心肌细胞的活性。(2)CEP作用于心肌细胞,出现细胞核碎裂现象和caspase-3激活。(3)CEP作用下p38 MAPK和ERK磷酸化水平显著增强,JNK的磷酸化状态未发生显著改变。(4)p38 MAPK磷酸化抑制剂SB203580显著减轻CEP对心肌细胞活性的抑制作用;ERK磷酸化抑制剂PD98059不能影响CEP对心肌细胞活性的抑制作用。结论: p38 MAPK参与CEP致心肌细胞凋亡作用。     

碱性成纤维细胞生长因子经ERK信号通路抑制卵巢癌CAOV3细胞凋亡

目的:研究卵巢癌CAOV3细胞中碱性成纤维细胞生长因子(bFGF)经MEK/ERK1/2信号转导通路对CREB、Bcl-2表达以及对细胞凋亡的影响作用。方法:无血清饥饿诱导细胞凋亡。分为对照组、bFGF组、bFGF PD98059组。Annexin-EGFP/PI荧光双染法检测细胞凋亡。Western印迹法检测ERK1/2、CREB以及Bcl-2蛋白表达。RT-PCR法检测Bcl-2的mRNA表达。结果:bFGF可抑制无血清饥饿诱导的细胞凋亡;时效依赖性地诱导ERK1/2活性增高、刺激CREB磷酸化、促进Bcl-2的mRNA及蛋白表达增加。bFGF作用CAOV3细胞15 min时ERK1/2活性达高峰;45 min时CREB磷酸化达峰值;Bcl-2的mREN表达高峰为6h,8h时蛋白表达最高。MEK1抑制剂PD98059可抑制bFGF的上述作用。结论:bFGF可能通过激活MEK/ERK1/2/CREB/Bcl-2信号转导途径抑制卵巢癌CAOV3细胞凋亡。     

降钙素基因相关肽通过ERK1/2信号通路对角质形成细胞增殖的影响

目的： 研究降钙素基因相关肽（CGRP）对角质形成细胞增殖活性的影响，并探讨其可能涉及的信号转导通路。方法： ①胸腺嘧啶掺入法（［3H］-TdR）观察CGRP诱导的角质形成细胞株HaCaT细胞增殖，及CGRP受体拮抗剂CGRP8-37、细胞外信号调节激酶ERK1/2特异性抑制剂PD98059对CGRP诱导的增殖活性的影响；②免疫印迹技术观察CGRP诱导后ERK1/2的磷酸化，及CGRP8-37、PD98059对ERK1/2磷酸化的影响。结果： ①CGRP在一定范围内可剂量依赖性地诱导HaCaT细胞增殖，该作用可被CGRP8-37和 PD98059阻断；②CGRP可时间依赖性地诱导HaCaT细胞ERK1/2的磷酸化，CGRP8-37和PD98059可减弱其作用。结论： CGRP可诱导HaCaT细胞增殖，CGRP受体及其相关的ERK1/2信号通路参与其调控机制。     

转化生长因子β1促进骨髓间充质干细胞Snail表达的信号转导通路

目的 探讨细胞外信号调节激酶1/2(ERK1/2)和磷脂酰肌醇3-激酶(PI3K)-Akt信号转导通路在转化生长因子β1(TGF-β1)引起骨髓间充质干细胞(BMSCs)Snail表达改变中的调控作用. 方法 采用密度梯度离心结合贴壁法分离、培养大鼠BMSCs,用免疫荧光法对培养第3代的细胞进行鉴定.应用Western blotting检测TGF-β1对p-ERK1/2及p-Akt表达的影响,以不同浓度ERK特异性抑制剂(PD98059)或PI3K通路特异性抑制剂(Wortmannin)干预后检测BMSCs ERK、Akt磷酸化水平变化,确定PD98059和Wortmannin分别抑制Snail诱导的BMSCs ERK和Akt磷酸化的有效浓度,进而用RT-PCR、Western blotting技术证实TGF-β1诱导骨髓间充质干细胞Snail mRNA及蛋白表达的影响. 结果 密度梯度离心结合贴壁法能有效分离、纯化大鼠BMSCs,免疫荧光检测显示,培养的细胞CD29、CD44表达阳性,而CD34、CD45表达阴性;Western blotting分析显示,TGF-β1作用6h后BMSCs p-Akt和p-ERK水平较对照组明显增高;Wortmannin和PD98059可分别以剂量依赖性抑制BMSCs p-Akt和p-ERK水平;可有效抑制TGF-β1诱导的BMSCs ERK及Akt的磷酸化,PD98059和Wortmannin相应浓度分别为30 μmol/L和40 nmol/L.PD98059(30 μmol/L)、Wortmannin(40 nmol/L)明显抑制了TGF-β1诱导的Snail mRNA及蛋白水平,而两者联合应用对骨髓间充质干细胞Snail mRNA及蛋白表达的抑制作用具有协同作用,与对照组相比,差异有统计学意义(P<0.05). 结论 TGF-β1能促进BMSCs的Snail的转录及蛋白的表达,且ERK1/2及PI3K转导通路的激活在此过程中具有调控作用.     

细胞外调节蛋白激酶信号通路参与机械牵张诱导肺泡上皮细胞高迁移率族蛋白B1的表达调控

目的 探讨细胞外调节蛋白激酶（ERK）信号通路在机械牵张诱导肺泡上皮细胞（A549）表达高迁移率族蛋白B1（HMGB1）中的作用。 方法 肺泡上皮细胞A549分为A、B、C 3组,A组为对照组;B组A549细胞施加14%牵张应变,牵张时间为4 h;C组细胞的牵张模式与B组相同,只是于施加牵张前用ERK的特异性抑制剂PD98059预处理A549细胞2h。分别用免疫细胞化学染色和RT-PCR检测细胞HMGB1蛋白和mRNA的表达,用Western blotting检测ERK激酶的活性。 结果 A549细胞施加14 %牵张应变后,HMGB1蛋白和mRNA表达明显增加,ERK激酶活性明显增高（P＜0.05）;该诱导激活作用可被PD98059阻断。 结论 机械牵张通过ERK信号通路,调节A549细胞的HMGB1基因和蛋白表达。     

SASH1通过MAP2K2和MAP4K4与ERK信号通路交互作用

目的 探讨新候选抑癌基因SASH1与细胞外调节蛋白激酶(ERK)信号通路的两个关键分子MAP2K2和MAP4K4的蛋白-蛋白相互作用关系.方法 用Xho Ⅰ和HpaⅠ构建SBP-Flag-SASH1-pBABE-puro反转录病毒载体,转染HEK-293T细胞,通过嘌呤霉素筛选出稳定表达外源性SASH1基因的细胞系.Western blot检测外源性Flag-SASH1蛋白表达,利用pull-down实验、质谱技术、免疫沉淀鉴定和分析与SASH1结合的并可能调节细胞增殖、转移和凋亡等的关键蛋白.用SASH1-siRNA1和SASH1-siRNA2分别转染MDA-MB-231细胞系,以空白组和Negative-siRNA组为对照.72 h后Western blot检测SASH1的干扰效果和P-ERK1/2水平.结果 成功构建稳定表达SBP-Flag-SASH1-pBABE-puro重组质粒的HEK-293T细胞系,SASH1与MAP2K2和MAP4K4结合并发生相互作用.SASH1-siRNA有效抑制MDA-MB-231细胞SASH1蛋白表达(P＜0.05),且P-ERK1/2在SASH1抑制组表达增加.结论 MAP2K2和MAP4K4是SASH1的重要的候选结合蛋白,SASH1可能通过与其直接或间接结合串话ERK信号传导通路,进而调节细胞增殖和迁移等细胞生物学功能.     

The mitogen-activated/extracellular signal-regulated kinase kinase 1/2 inhibitor U0126 induces glial fibrillary acidic protein expression and reduces the proliferation and migration of C6 glioma cells

The extracellular signal-regulated kinase (ERK) signaling pathway has been implicated in diverse cellular functions. ERK and its activating kinase, mitogen-activated/extracellular signal-regulated kinase kinase (MEK), are downstream of cell surface receptors known to be up-regulated in many malignant gliomas. We sought to investigate the role of ERK in glioma cell migration, proliferation and differentiation using the rat-derived C6 glioma cell line and the MEK inhibitor, U0126. Treatment of C6 cells with U0126 caused a significant concentration-dependent reduction in cell proliferation and migration and also induced expression of glial fibrillary acidic protein, a marker of astrocytic differentiation. These results suggest that the ERK pathway regulates glioma cell proliferation, migration and differentiation.     

KinMutBase: a registry of disease-causing mutations in protein kinase domains

A large number of disease-causing mutations have been identified from several protein kinases. KinMutBase is a comprehensive knowledge base for human disease-related mutations in protein kinase domains (http://bioinf.uta.fi/KinMutBase/). The latest version contains 582 different mutations for 1,790 cases in 1,322 families. KinMutBase entries are described on the DNA, mRNA, and protein level. Numbers for affected patients and families are also provided. KinMutBase has extensive amount of links and cross-references to literature, other databases, and information sources. There are numerous interactive pages about sequences, structures, mutation statistics, and diseases. Detailed statistical study was done on frequencies of different types of mutations both on the DNA and protein level in serine/threonine kinase (PSK) and tyrosine kinase (PTK). Three-dimensional structures indicate clustering of disease-related mutations mainly to conserved subdomains, and substrate and coligand binding amino acids, although mutations appear throughout the sequences. CpG containing codons, especially for arginine, constitute the majority of mutational hotspots. There are certain clear differences in mutation patterns and types between PSKs and PTKs.     

Evaluation of Signal Transduction Pathways in Chemoattractant-Induced Human Monocyte Chemotaxis

The intracellular signaling pathways involved in human monocyte chemotaxis toward a variety of chemoattractant molecules were evaluated using selected pharmacological agents. Neither phosphatidylinositol-3-kinase (PI3K) or extracellular signal-regulated kinase (ERK) activity were required for monocyte migration toward monocyte chemoattractant protein-1 (MCP-1), RANTES (Regulated on Activation, Normal T cell Expressed and Secreted), macrophage inflammatory protein-1 (MIP-1) or formyl-Met-Leu-Phe (fMLP), since pretreatment with wortmannin or LY294002, or with PD098059, had no effect on the chemotactic response. Addition of forskolin and IBMX significantly attenuated chemotaxis to each of these chemoattractants and was reversed by co-treatment with Rp-cAMP, a competitive inhibitor of cAMP-dependent protein kinase A. Incubation with the protein kinase C (PKC) inhibitor GF109203X-HCl (GF109) did not affect monocyte migration, but pretreatment of monocytes with PMA significantly impaired the response to each of these chemotactic agents. Inhibition by PMA was reversed by co-treatment with GF109, implying that heterologous PKC activation is capable of desensitizing chemokine and fMLP-induced monocyte chemotaxis. These results help to define the signalling pathways involved in human monocyte chemotaxis and suggest pharmacological approaches to evaluating the cross-desensitization of chemoattractant-induced leukocyte migration.     

Detection of antagonistic cellular regulatory functions by the gene-gene interference method in yeast

It was previously assumed that a new genetic method in yeast, termed gene-gene interference, leads to the selection of genes that antagonize, and/or are antagonized by, the particular reference gene used for their selection (Daniel 1993). In this paper two pieces of evidence are advanced in favour of this view. Firstly, the reconstitution of a system of known antagonistic genes was shown to be detectable by the gene-gene interference method. Secondly, sinceART1, a new gene selected in reference to the protein kinase A gene, has been shown to contain in its deduced polypeptide a putative site for phosphorylation by protein kinase A, a mutagenesis study directed toward this putative site has been performed. Two phenotypes-in vivo filamenting activity and gene-gene interference relative to the protein kinase A gene-were tested with the various mutations thus obtained and found to be consistent with the hypothesis that, under physiological conditions, phosphorylation by protein kinase A exerts an inhibitory effect on Art1 activity. The relevance of these findings on the mechanisms and potential applications of the gene-gene interference phenomenon is discussed.     

蛋白激酶C-δ的研究进展

PKC-δ是PKC家族的一种亚型。目前,PKC-δ的结构及其激活与转位机制尚不明了。PKC-δ在细胞的生长、分化及凋亡、肿瘤进展中有非常重要的作用,并与肿瘤耐药性密切相关。     

Curcumin attenuates ethanol-induced toxicity in HT22 hippocampal cells by activating mitogen-activated protein kinase phosphatase-1

Ethanol causes neurotoxicity through formation of reactive oxygen species and activation of mitogen-activated protein kinase (MAPK) pathways. MAPK phosphatase-1 (MKP-1) is one of the phosphatases responsible for dephosphorylation/deactivation of MAPKs. In this report, we examined the potential involvement of MKP-1 in cytoprotective effects of the well-known antioxidant curcumin. In HT22 hippocampal cells, ethanol caused cell death and activation of p38 MAPK and other two kinases. Blockage of p38 MAPK by its inhibitor protected HT22 cells against ethanol-induced toxicity. Curcumin attenuated ethanol-induced cell death, inhibited activation of p38 MAPK, and activated MKP-1. In HT22 cells transiently transfected with small interfering RNA against MKP-1, curcumin failed to inhibit ethanol-induced activation of p38 MAPK and to protect HT22 cells from ethanol-induced toxicity. Our results suggest that curcumin can attenuate ethanol-induced neurotoxicity by activating MKP-1 which acts as the negative regulator of p38 MAPK. This novel pathway may contribute to and explain at least one of the cytoprotective actions of curcumin.