ERK1/2信号通路阻断剂PD98059对慢性高原病患者骨髓有核红细胞中Ras、BRaf、MEK、ERK1/2表达的影响

目的:探讨ERK1/2信号通路阻断剂PD98059对Ras、B型丝/苏氨酸蛋白激酶(BRaf)、丝裂原活化蛋白激酶(MEK)、细胞信号调节激酶1/2(ERK1/2)表达的影响,以期为慢性高原病(chronic mountain sickness,CMS)的基础研究和临床治疗探讨新的途径。方法:选取CMS患者16例,取骨髓液分离单个核细胞,以CD71与CD235a抗体磁珠分选阳性细胞,将细胞分为5组:空白对照组、DMSO溶剂组及PD98059 5、10和20μmol/L组。在低氧条件下培养72 h,应用ELISA法测定培养骨髓有核红细胞上清液中Ras-GTP水平,RT-PCR法测定骨髓有核红细胞中BRaf、MEK、ERK1/2 mRNA的表达,Western blot方法检测骨髓有核红细胞中p-BRaf、p-MEK、pERK1/2蛋白表达。结果:PD98059对各组Ras-GTP的水平无明显影响(P=0.798)。溶剂组与空白对照组相比,BRaf、MEK mRNA的表达水平差异无统计学意义(P=0.826、P=0.298)。与PD98059 20 mol/L比较,其余4组ERK1/2 mRNA的表达水平差异有统计学意义(P=0.001、P=0.002)。溶剂组与空白对照组相比,p-BRaf、p-MEK蛋白的表达差异无统计学意义(P=0.370、P=0.351)。与PD98059 20 mol/L比较,其余4组p-ERK1/2蛋白水平差异有统计学意义(P0.001、P0.007)。结论:PD98059能下调骨髓有核红细胞ERK1/2 mRNA及p-ERK1/2蛋白的表达。Ras/Raf/MEK/ERK 1/2通路是调控CMS骨髓有核红细胞的主要信号传导途径,可能参与了慢性高原病的发病过程。     

蛇六谷石油醚提取物对K562细胞生物学特性的影响及其机制

目的:探讨蛇六谷石油醚提取物(SLG)抑制白血病K562细胞增殖、促进凋亡和诱导分化的作用。方法:SLG处理K562细胞,同时加入ERK信号通路阻滞剂PD98059。采用MTT检测细胞活力,采用流式细胞术检测细胞凋亡率及分化相关抗原表达阳性的细胞比例,采用Western blot检测ERK1/2和p-ERK1/2的蛋白表达水平。结果:SLG 50、100、200 mg/L能够降低K562细胞的增殖活力,其抑制作用呈剂量依赖性(r=0.9997)。SLG能够提高细胞凋亡率及分化相关抗原CD11b、CD14和CD42b表达阳性的细胞比例,同时能够上调p-ERK1/2的表达。PD98059可部分逆转SLG促凋亡和分化的作用。结论:SLG通过ERK信号通路抑制K562细胞增殖、促进凋亡和诱导分化。     

辛伐他汀通过MEK/ERK信号转导通路上调突触素表达

目的研究辛伐他汀(SV)对体外培养大鼠大脑皮层神经元突触素(SYP)的影响及信号转导机制。方法从新生Sprague-Dawley大鼠大脑皮层分离和培养神经元,4 d后分为对照组、SV处理组(2、4、8μmol/L作用48 h)、PD98059处理组和SV+PD98059处理组(先加入10μmol/L阻断剂PD98059作用30 min,再加入10μmol/L SV作用48 h)。应用免疫荧光检测法检测SYP表达,Western blot检测磷酸化丝裂原细胞外激酶(p-MEK)、磷酸化细胞外调节蛋白激酶1(p-ERK1)和磷酸化细胞外调节蛋白激酶2(p-ERK2)水平。结果免疫荧光检测显示,4μmol/L SV可明显增强SYP免疫反应性。Western blot检测显示,8μmol/L SV可显著增高SYP、p-MEK、p-ERK1和p-ERK2水平。应用PD98059可显著降低SV引起的SYP、p-MEK、p-ERK1和p-ERK2水平上调。结论SV可通过激活MEK/ERK信号转导通路上调SYP表达。     

抑制ERK增强白血病和卵巢癌耐药细胞系化疗敏感性

为了研究细胞外调节蛋白激酶(extracelluar regulated protein kinases，ERK)和端粒酶在白血病和卵巢癌细胞耐药中的作用，应用流式细胞术检测细胞凋亡率，应用端粒重复序列扩增法(TRAP)和生物发光分析法去除检测端粒酶活性，应用Weestern blot法检测磷酸化ERK1/2蛋白(ERK1和ERK2)表达水平。结果表明：ERK激酶1(MEK1)特异性抑制剂PD98059能增强HL-60／E6细胞对三尖杉酯碱(HRT)的敏感性，PD98059也能增强COCl／DDP细胞对顺铂(DDP)的敏感性。PD98059与化疗药物HRT和DDP均可以降低细胞内磷酸化ERK表达，抑制端粒酶活性，但PD98059与化疗药物的联合作用明显强于其各自的单独作用。结论：通过阻抑ERK通路，降低磷酸化ERK1/2蛋白表达水平，进而下调端粒酶活性，可以达到增强白血病和卵巢癌耐药细胞对HRT或DDP敏感性的目的。     

肿瘤抑素影响血管瘤内皮细胞凋亡的相关机制分析

目的研究肿瘤抑素对血管瘤内皮细胞的增殖与凋亡过程的调节作用,为临床婴幼儿血管瘤的治疗提供参考。方法血管瘤内皮细胞培养后随机分为5组:对照组、PD98059组、肿瘤抑制素低剂量、中剂量和高剂量组。除对照组给予生理盐水外,其余各组给予PD98059(10μM)处理2 h,肿瘤抑制素低剂量、中剂量和高剂量组分别给予1μM、10μM、100μM的肿瘤抑制素处理2 h。免疫印迹法或荧光定量法分析各组细胞凋亡相关蛋白Caspase3/9、ERK信号通路关键蛋白ERK1/2和MEK及氧化应激蛋白NOX4的表达,DHE染色法分析各组细胞的氧化应激状态。结果与对照组相比,PD98059组血管瘤内皮细胞内ROS水平明显降低、细胞凋亡蛋白Caspase3/9的表达明显升高;同时ERK信号通路关键蛋白的表达明显增强,而肿瘤抑制素低剂量、中剂量和高剂量组作用与PD98059作用一致,且具有剂量依从性。结论肿瘤抑制素通过激活氧化应激状态、ERK信号及抑制细胞凋亡蛋白通过发挥对血管瘤内皮细胞增殖的抑制作用。     

纤维连接蛋白诱导人胚肺成纤维细胞增殖信号转导机制探讨

【目的】探讨纤维连接蛋白（FN）诱导人胚肺成纤维细胞（HFL1）增殖的细胞外信号调节激酶（ERK）信号转导通路。【方法】用四甲基偶氮唑蓝（MTT）法检测各组细胞增殖情况。采用不同浓度FN刺激HFL1并观察不同浓度下细胞ERK信号转导通路阻断剂PD98059对FN诱导HFL1增殖作用的影响;并用蛋白免疫印记法（Western Blot）观察FN浓度为50ng／mL时,PD98059对HFL1中磷酸化细胞外信号调节激酶（p-ERK）表达的影响。[结果]FN对HFL1诱导增殖作用呈剂量依赖性升高趋势,在50ng／mL时作用显著;ERK抑制剂PD98059可抑制FN诱导的HFL1细胞增殖。【结论】FN诱导HFL1的细胞增殖可以通过ERK信号转导途径实现。     

SH2B1沉默对胃癌SGC-7901细胞增殖、凋亡及PI3K/AKT通路的影响

目的研究沉默SH2B1基因表达对胃癌SGC-7901细胞增殖、凋亡及3-磷酸肌醇激酶(PI3K)/蛋白质丝氨酸苏氨酸蛋白激酶(AKT)通路的影响。方法体外培养胃癌SGC-7901细胞,采用SH2B1 siRNA转染SGC-7901细胞作为研究组,采用国际通用的与所有基因均无同源序列的non-target siRNA转染作为阴性对照组(NC组),以未经处理的胃癌SGC-7901细胞作为空白对照组(BC组),48h后收集各组转染成功细胞,采用荧光定量聚合酶链反应(qRT-PCR)检测SH2B1 mRNA表达情况,采用蛋白质印迹法(Western Blot)检测SH2B1蛋白表达情况;采用细胞计数试剂盒(CKK-8)检测细胞增殖情况,采用流式细胞仪检测细胞凋亡,同时检测Ki67、增殖细胞核抗原(PCNA)、Caspase-9、PI3K、AKT、p-AKT蛋白表达情况。结果研究组SGC-7901细胞SH2B1蛋白及mRNA表达量较BC组和NC组明显降低,差异有统计学意义(P<0.05);转染后,siRNA组SGC-7901细胞增殖明显受到抑制、平板克隆形成率较BC组和NC组明显降低,凋亡率明显升高,差异均有统计学意义(P<0.05);与BC和NC组比较,研究组SGC-7901细胞PI3K、p-AKT蛋白、Ki67及PCNA蛋白呈低表达,差异有统计学意义(P<0.05),Caspase-9蛋白呈高表达,AKT蛋白表达差异无统计学意义(P>0.05)。结论沉默SH2B1基因表达可能通过抑制PI3K/ATK信号通路激活,抑制SGC-7901细胞增殖,促进凋亡。     

脑源性神经营养因子通过AKT和ERK1/2信号通路诱导内皮细胞血管生成

本研究探讨脑源性神经营养因子（BDNF）促进血管新生的作用及其参与的信号通路,为抗肿瘤血管生成的研究提供新的实验依据。以人脐静脉内皮细胞为对象,采用Western blot方法检测细胞内磷酸化Akt、ERK1/2蛋白质的表达;采用Transwell小室迁移实验和管腔形成实验评价体外内皮细胞血管新生的能力,MTT法检测内皮细胞增殖活性,FITC-Annexin-Ⅴ/PI双染流式细胞术分析细胞调亡。结果表明：BDNF以时间依赖性的方式激活PI3K/Akt和MEK1/ERK信号通路。应用PI3K激酶抑制剂Ly294002、MEK1激酶抑制剂PD98059可以明显阻断BDNF对PI3K/Akt、MEK1/ERK信号通路的激活。100ng/ml的BDNF体外促内皮细胞血管新生能力与25ng/ml血管内皮生长因子（VEGF）相当,其中BDNF诱导的细胞迁移分别被Ly294002和PD98059阻断,其抑制率分别约为74%和36%;同样,Ly294002、PD98059可部分阻断BDNF诱导的小管形成效应,其阻断率分别约57%和37%;而BDNF的促增殖效应仅被PD98059拮抗,抑制凋亡效应仅受Ly294002影响。结论：BDNF在体外有促血管新生的作用。PI3K/Akt和MEK1/ERK信号通路以不同机制共同调节这一过程,其中PI3K/Akt信号通路起着更为重要的调节作用。     

表皮生长因子受体活化与胰腺癌细胞解离关系的实验研究

目的 明确表皮生长因子受体(EGFR)活化参与胰腺癌细胞解离调节的分子机制.方法 通过免疫荧光法检测仓鼠高转移株(PC-1.0)和低转移株(PC-1)胰腺癌细胞中EGFR、活化(磷酸化)EGFR (p-EGFR)、活化(磷酸化)丝裂原活化蛋白激酶激酶2 (p-MEK1/2)及活化(磷酸化)细胞外信号调节激酶1/2 (p-ERK1/2)的表达变化及其与胰腺癌细胞解离状态变化的关系.结果 胰腺癌细胞解离因子(DF)明显诱导低转移株胰腺癌细胞(PC-1)中EGFR、p-EGFR、p-MEK1/2和p-ERK1/2的表达,同时诱导其细胞克隆解离.相反,AG1478(EGFR活化抑制剂)明显抑制高转移株胰腺癌细胞(PC-1.0)中EGFR、p-EGFR、p-MEK1/2和p-ERK1/2的表达,同时诱导PC-1.0细胞聚集成细胞克隆.结论 表皮生长因子受体活化后激活MEK/ERK信号通路,从而参与胰腺癌细胞解离的调节.     

槲皮素对胃癌细胞SGC-7901上皮间质转化的抑制作用

目的探讨槲皮素对人胃癌细胞SGC-7901上皮间质转化的影响及机制。方法胃癌细胞SGC-7901分为对照组(普通培养液)、LY294002组(培养液+LY294002)、槲皮素组(培养液+槲皮素);采用MTT法检测槲皮素对胃癌细胞SGC-7901增殖的影响,依据细胞生长抑制率计算槲皮素对胃癌细胞SGC-7901的半数抑制浓度(median inhibitory concentration,IC_(50))值,参照IC_(50)值进行后续实验;采用划痕试验检测3组胃癌细胞SGC-7901增殖、迁移能力;采用Western blot法检测胃癌细胞AKT、p-AKT、Snail、Vimentin及E-钙黏附素(E-cadherin)蛋白表达情况;采用荧光定量PCR法检测3组胃癌细胞上皮间质转化相关因子Snail、Vimentin及E-cadherinmRNA的表达情况。结果槲皮素对胃癌细胞SGC-7901有明显的增殖抑制作用,其IC_(50)为(112.9±2.05)μmol/L;LY294002组胃癌细胞迁移距离[(0.16±0.03)mm]、槲皮素组胃癌细胞迁移距离[(0.15±0.02)mm]均低于对照组[(0.44±0.04)mm](P0.05),LY294002组与槲皮素组比较差异无统计学意义(P0.05);Snail、Vimentin、p-AKT蛋白表达水平在LY294002组(0.760±0.003,0.750±0.006,0.71±0.03)、槲皮素组(0.750±0.006,0.690±0.004,0.68±0.02)均明显低于对照组(1,1,1),E-cadherin表达在LY294002组(2.89±0.19)与槲皮素组(3.66±0.18)均高于对照组(1)(P0.05);LY294002组、槲皮素组、对照组AKT蛋白表达水平(1.03±0.02,1.02±0.01,1)比较差异无统计学意义(P0.05);Snail、Vimentin mRNA表达水平在LY294002组(0.72±0.02,0.78±0.03)、槲皮素组(0.71±0.01,0.79±0.03)均明显低于对照组(1,1),E-cadherin mRNA表达水平在LY294002组(2.51±0.08)、槲皮素组(2.77±0.16)均高于对照组(1)(P0.05);LY294002组Snail、Vimentin、E-cadherin mRNA及Snail、Vimentin、E-cadherin、p-AKT蛋白表达水平与槲皮素组比较差异均无统计学意义(P0.05)。结论槲皮素对人胃癌细胞SGC-7901上皮间质转化有抑制作用,其作用机制可能是抑制AKT信号通路。     

Rat parathyroid hormone 1-34 signals through the MEK/ERK pathway to induce cardiac hypertrophy

This study aimed to characterize the role of the mitogen-activated protein kinase (MAPK) kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway in cardiac hypertrophy induced by parathyroid hormone (PTH). Various concentrations of rat PTH1-34 were used to induce hypertrophy in neonatal rat ventricular cardiomyocytes, and the effects were compared with control cells and those treated with PD98059, a selective inhibitor of MEK1. Hypertrophy was assessed in terms of cell diameter, atrial natriuretic peptide (ANP) mRNA expression and protein synthesis; the MEK/ERK pathway was assessed by measuring levels of phosphorylated ERK1/2. Treatment with PTH1-34 at 100 nM for 24 h effectively induced cardiac hypertrophy (increased cell diameter, protein synthesis and ANP mRNA expression) and also increased levels of phosphorylated ERK1/2 compared with normal control cells. Treatment with PTH1-34 plus PD98059 significantly attenuated these changes. These results demonstrate that inhibition of the MEK/ERK pathway blocks PTH1-34-induced cardiac hypertrophy, suggesting that PTH1-34 might signal through the MAPK pathway to induce hypertrophy in cardiomyocytes.     

促分裂原活化蛋白激酶信号阻断剂在TPO促进UT7细胞增殖和分化中的作用

目的探索促分裂原活化蛋白激酶(mitogenactivatedproteinkinase,MAPK)信号阻断剂对巨核细胞生长分化因子(TPO)促进UT7细胞增殖和分化作用,阐明TPO对UT7细胞作用的机制。方法将EGFPpMSCV和MEK1pMSCV质粒转染UT7细胞;转染细胞与TPO共培养,Westernblot法检测UT7细胞MEK1(MAPK/Erkkinase1)磷酸化;观察转染突变(Ser222A)的MEK1和MAPK阻断剂PD98059对UT7细胞增殖的影响;采用流式细胞仪检测转染突变(Ser222A)的MEK1和MAPK阻断剂PD98059对UT7细胞表达CD41的影响。结果①重组逆转录病毒载体MEK1pMSCV和EGFPpMSCV转染UT7细胞,EGFP阳性率为60.73%。②TPO不同的作用时间(1h,3h),实验组磷酸化MEK1均低于对照组(P值均<0.05)。③MAPK阻断剂PD98059和外源突变MEK基因阻断了TPO对UT7细胞的增殖作用,DMSO对照组的细胞增殖率为98.58%,PD98059组的细胞增殖率为39.00%(P<0.05);转染EGFPpMSCV组细胞增殖率为102.12%,转染MEK1pMSCV组细胞增殖率为48.93%(P<0.05)。④MAPK阻断剂PD98059组UT7细胞CD41表达(10.27%)明显低于对照组(36.43%),转染MEK1pMSCV组UT7细胞CD41表达(24.03%)明显低于转染EGFPpMSCV组(40.16%)。结论TPO诱导UT7细胞MEK1磷酸化,TPO作用时间与UT7细胞MEK1的磷酸化有明显的关系,MAPK信号转导通路介导TPO促进UT7细胞     

Mitogen-activated protein/extracellular signal-regulated kinase kinase (MEK) inhibitors restore anoikis sensitivity in human breast cancer cell lines with a constitutively activated extracellular-regulated kinase (ERK) pathway

Anchorage-independent growth is a hallmark of oncogenic transformation. We reported that the mitogen-activated protein/extracellular signal-regulated kinase kinase (MEK) inhibitor U0126 inhibited anchorage-independent growth of Ki-ras-transformed rat fibroblasts by simultaneously blocking both extracellular signal-regulated kinase (ERK) and mammalian target of rapamycin (mTOR)-p70(S6K) pathways. Here, we examined the effects of U0126 on the growth of eight human breast cancer cell lines. U0126 selectively repressed anchorage-independent growth of MDA-MB231 and HBC4 cells, two lines with constitutively activated ERK. Loss of contact with substratum triggers apoptosis in many normal cell types, a phenomenon termed anoikis. U0126 sensitized MDA-MB231 and HBC4 to anoikis, i.e., upon treatment with U0126, cells deprived of anchorage entered apoptosis, whereas adherent cells remained viable. Another MEK inhibitor PD98059 also induced anoikis sensitivity in MDA-MB231 cells but not in HBC4 cells. However, HBC4 cells were sensitized to anoikis when PD98059 was combined with the mTOR inhibitor rapamycin. To study the biochemical basis for induction of anoikis sensitivity, we examined the effects of the MEK inhibitors on ERK and p70(S6K) pathways in anchored versus nonanchored cells. As in Ki-ras-transformed rat fibroblasts, U0126 reduced activation of both ERK and p70(S6K) in MDA-MB231 and HBC4 cells, irrespective of anchorage. PD98059, in anchored cells, was more selective for the ERK pathway and did not significantly block the p70(S6K) pathway. Removal of anchorage substantially sensitized p70(S6K) to PD98059 in MDA-MB231 cells, whereas p70(S6K) in suspended HBC4 cells remained fairly refractory. U0126 was either without effect or less inhibitory on p70(S6K) in MDA-MB453 and SKBR3, two cell lines in which anoikis sensitivity was not induced. Thus, susceptibility of the p70(S6K) pathway to MEK inhibitors appeared to be an important determinant of anoikis sensitivity. The results indicate that concurrent inhibition of MEK-ERK and mTOR-p70(S6K) pathways induces apoptosis in MDA-MB231 and HBC4 cells when cells are deprived of anchorage but not when anchored. Inhibitors of MEK-ERK and mTOR-p70(S6K) pathways may provide a therapeutic strategy to selectively target neoplasms proliferating at ectopic locations, with acceptable effects on normal cells in their proper tissue context.     

The mitogen-activated protein kinase/extracellular signal-regulated kinase kinase inhibitor PD184352 (CI-1040) selectively induces apoptosis in malignant schwannoma cell lines

Type 1 neurofibromatosis (NF1) is a common autosomal dominant disorder that results in neuroectodermal tumors. The NF1 tumor-suppressor gene encodes neurofibromin, which includes a GTPase-activating domain for Ras inactivation. Affinity purification showed N-Ras to be the predominant activated isoform of Ras in two independent neurofibrosarcoma cell lines from NF1 patients (lines ST88-14 and NF90-8). These NF1 cells also demonstrated increased constitutive activity of the extracellular signal-regulated kinases 1 and 2 (ERK1,2) mitogen-activated protein (MAP) kinases compared with a sporadic malignant schwannoma cell line that maintains neurofibromin expression (STS-26T). Thus, MAP kinase kinase (MEK) inhibitors may be a rational approach to NF1 therapy. The MEK inhibitors PD98059 [2'-amino-3'-methoxyflavone], PD184352 (also called CI-1040) [2-(2-chloro-4-iodo-phenylamino)-N-cyclopropylmethoxy-3,4-difluoro-benzamide], and U0126 [1,4-diamino-2,3-dicyano-1,4-bis(2-aminophenylthio)butadiene] all produced concentration-dependent suppression of the proliferation of the three cell lines. Individual MEK inhibitors had similar effects in all three cell lines. However, only the antiproliferative effects of PD184352 correlated closely with the elimination of ERK1,2 MAP kinase activities. PD98059 was primarily cytostatic, whereas U0126 and PD184352 were cytotoxic. Only PD184352 induced apoptosis in all three lines, as indicated by morphology, activation of DEVDase, procaspase-3 cleavage, and the appearance of populations having sub-G(0)/G(1) DNA contents. The differential effects of the MEK inhibitors on cell survival were not dependent on p53 status or effects on the ERK5 pathway. PD184352 was also proapoptotic to primary rat Schwann cells. Hence, although PD184352 effectively killed neurofibrosarcoma cells, its effects on normal Schwann cells may limit its usefulness in the clinic.     

骨髓间充质干细胞增殖与成骨分化中电磁场激活ERK通路的作用

背景:研究表明电磁场可调节骨髓间充质干细胞的增殖和分化,但其具体机制尚不清楚.目的:从ERK信号途径探讨电磁场诱导大鼠骨髓间充质干细胞增殖与分化成骨的作用.方法:取第3代生长良好的大鼠骨髓间充质干细胞,暴磁组给予15 Hz、1 mT的正弦波电磁场刺激,PD98059+暴磁组在电磁场刺激前给予20 μmol/L ERK阻断剂PD98059,PD98059组仅给PD98059不进行电磁场刺激,对照组正常培养.电磁场刺激后,收集各组细胞,Western blot法检测ERK通路的活性,MTT法检测细胞增殖活性,碱性磷酸酶试剂盒检测细胞碱性磷酸酶活性.结果与结论:电磁场刺激后,细胞ERK1/2磷酸化水平、细胞的增殖活性、及碱性磷酸酶活性均明显升高(P < 0.01);PD98059可明显抑制ERK1/2磷酸化水平及细胞增殖活性的升高(P < 0.01),而在一定程度上提高细胞的碱性磷酸酶活性(P < 0.01).说明电磁场刺激可通过激活骨髓间充质干细胞ERK信号通路,并且主要通过该途径促进骨髓间充质干细胞的增殖;而在脉冲电磁场促进骨髓间充质干细胞分化成骨的过程中,激活ERK信号通路所起的作用较小.     

骨髓间充质干细胞增殖与成骨分化中电磁场激活ERK通路的作用

背景：研究表明电磁场可调节骨髓间充质干细胞的增殖和分化,但其具体机制尚不清楚。目的：从ERK信号途径探讨电磁场诱导大鼠骨髓间充质干细胞增殖与分化成骨的作用。方法：取第3代生长良好的大鼠骨髓间充质干细胞,暴磁组给予15Hz、1mT的正弦波电磁场刺激,PD98059＋暴磁组在电磁场刺激前给予20μmol/L ERK阻断剂PD98059,PD98059组仅给PD98059不进行电磁场刺激,对照组正常培养。电磁场刺激后,收集各组细胞,Western blot法检测ERK通路的活性,MTT法检测细胞增殖活性,碱性磷酸酶试剂盒检测细胞碱性磷酸酶活性。结果与结论：电磁场刺激后,细胞ERK1/2磷酸化水平、细胞的增殖活性、及碱性磷酸酶活性均明显升高（P〈0.01）;PD98059可明显抑制ERK1/2磷酸化水平及细胞增殖活性的升高（P〈0.01）,而在一定程度上提高细胞的碱性磷酸酶活性（P〈0.01）。说明电磁场刺激可通过激活骨髓间充质干细胞ERK信号通路,并且主要通过该途径促进骨髓间充质干细胞的增殖;而在脉冲电磁场促进骨髓间充质干细胞分化成骨的过程中,激活ERK信号通路所起的作用较小。     

雷公藤内酯醇对人胃癌细胞SGC7901增殖及表达血管内皮生长因子的影响

目的:研究雷公藤内酯醇(TL)对人胃癌细胞SGC7901增殖及表达血管内皮生长因子(VEGF)的影响。方法:采用增殖抑制试验(MTT法)了解TL对SGC7901细胞的增殖抑制作用,采用逆转录聚合酶链式反应(RT-PCR)了解TL对VEGFmRNA表达的影响,采用免疫组织化学方法了解TL对VEGF蛋白表达的影响。结果:12.5～200ng/mL的TL作用于人胃癌细胞SGC790112～48h,其生长和增殖都受到一定程度的抑制,并且呈剂量和时间依赖性;TL作用于人胃癌细胞SGC790124h,下调VEGFmRNA及VEGF蛋白的表达(P<0.01)。结论:TL可以通过抑制肿瘤细胞VEGF的表达而发挥抗肿瘤作用。     

丁酸钠诱导人骨髓增生异常综合征细胞株SKM-1分化作用中细胞外信号调节激酶通路的改变

本研究探讨细胞外信号调节激酶（ERK）通路在丁酸钠（NaB）诱导人骨髓增生异常综合征细胞株SKM-1分化中的作用,阐明丁酸钠诱导SKM-1细胞分化的分子机制.用Western blot方法检测总ERK和磷酸化ERK的表达水平;将ERK特异性的抑制剂PD98059与丁酸钠联合应用,观察它们对SKM-1细胞生长曲线的影响及分化效应,并用Western blot方法检测P21和组蛋白脱乙酰酶（HDAC）蛋白质的表达水平.结果表明：SKM-1细胞经1mmol/L的丁酸钠作用后,总ERK的表达水平未发生变化,而磷酸化ERK的表达水平下降;丁酸钠及丁酸钠＋PD98059均可以上调P21和HDAC蛋白质的表达水平,且丁酸钠联合PD98059的作用强于丁酸钠单用.结论：ERK通路抑制是丁酸钠诱导SKM-1细胞分化的重要分子机制.