吴茱萸碱诱导A375-S2细胞死亡过程中对ERK激酶的调控

目的:对比吴茱萸碱与化疗药物对A375-S2细胞的细胞毒活性,并且研究PKC及ERK激酶在吴茱萸碱诱导A375-S2细胞死亡中的作用。 方法: MTT法,Western印迹法。 结果:虽吴茱萸碱对A375-S2细胞毒作用比化疗药物放线菌素D、顺铂和5-氟尿嘧啶弱,但对药物撤除后细胞继续增殖能力的影响远胜于3种化疗药物。低浓度(10 μg/L) 佛波酯 (PMA) 引起的PKC的激活可部分抑制吴茱萸碱引起的细胞死亡,PKC及ERK抑制剂可逆转这种作用,而且吴茱萸碱减少了ERK蛋白表达,并降低了ERK的磷酸化水平。结论: 吴茱萸碱对A375-S2细胞的细胞毒作用即使在药物撤除后仍对细胞继续增殖能力产生抑制作用。吴茱萸碱可通过减少ERK及磷酸化ERK的蛋白表达而阻断ERK激酶对细胞的保护作用。     

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。     

干扰Arf6抑制人前列腺癌细胞系DU145增殖、迁移及侵袭

目的观察干扰二磷酸腺苷核糖基化因子6(Arf6)对人前列腺癌细胞系DU145增殖、迁移及侵袭的影响,并初步探讨其调控机制。方法脂质体转染法将靶向Arf6的特异性siRNA序列、无效序列转染至DU145细胞,分别设为干扰组和NC组,不做处理为空白组。蛋白免疫印迹(Western blot)检测siRNA干扰效率;MTT法检测细胞增殖;划痕试验及Transwell试验检测细胞迁移及侵袭;实时荧光定量聚合酶链反应(RT-qPCR)及Western blot检测Arf6、丝裂原活化的细胞外信号调节激酶(MEK)、细胞外信号调节激酶(ERK)、Ras相关C3肉毒素底物1(Rac1)mRNA及蛋白表达、磷酸化MEK(pMEK)、pERK蛋白表达。结果靶向Arf6的特异性siRNA序列干扰活性为62.67%±4.38%。干扰组不同时刻细胞增殖均显著低于空白组和NC组(P0.05);干扰组细胞迁移率、穿膜细胞数均显著低于空白组及NC组(P0.05);干扰组Arf6、Rac1 mRNA及蛋白相对表达量、pMEK/MEK、pERK/ERK蛋白比值显著低于空白组及NC组(P0.05)。结论干扰Arf6可抑制人前列腺癌细胞系DU145增殖、迁移及侵袭能力,可能与下调pMEK、pERK、Rac1蛋白表达,抑制MEK/ERK信号通路有关。     

GCS通过MEK/ERK通路调控白血病多药耐药细胞凋亡相关基因bcl-2的表达

目的:探讨葡萄糖神经酰胺合成酶(GCS)是否通过MEK/ERK信号通路调控凋亡相关基因bcl-2的表达,从而诱导人白血病K562/A02细胞多药耐药。方法:用小干扰RNA(siRNA)靶向干扰K562/A02细胞中GCS的表达,real-time PCR、Western blotting检测Bcl-2、磷酸化及总ERK水平;用MEK特异性化学抑制剂U0126抑制MEK/ERK信号通路的活化,real-time PCR与Western blotting技术分别检测Bcl-2 mRNA与蛋白水平;CCK-8试剂盒检测细胞存活情况。结果:与阴性对照组比较,GCS siRNA明显抑制K562/A02细胞GCS和Bcl-2的表达,并抑制MEK/ERK信号通路的活化;U0126使Bcl-2 mRNA及蛋白水平呈浓度依赖性下降,并使K562/A02细胞ADM敏感性增加。结论:GCS通过MEK/ERK信号通路调控K562/A02细胞株中凋亡相关基因bcl-2的表达,从而诱导白血病细胞多药耐药。     

过表达Raf激酶抑制蛋白(RKIP)抑制人肝星状细胞增殖

目的研究Raf激酶抑制蛋白(RKIP)对LX-2人肝星状细胞增殖的影响。方法用重组质粒pc DNA3.1-RKIP转染LX-2细胞,G418筛选并培养稳定转染的细胞。MTT法和集落形成试验检测过表达RKIP对LX-2细胞增殖、集落生成的影响;Western blot法检测RKIP、α平滑肌肌动蛋白(α-SMA)、1型胶原蛋白(Col1)、基质金属蛋白酶1(MMP-1)、MMP-2及胞外信号调节激酶/丝裂原激活蛋白激酶(ERK/MAPK)信号通路相关蛋白的表达水平。结果与对照细胞相比,过表达RKIP明显抑制LX-2细胞增殖和集落形成,下调Col1、α-SMA、MMP-1和MMP-2蛋白表达,降低ERK/MAPK磷酸化水平。结论过表达RKIP抑制LX-2细胞的增殖,其机制与抑制ERK/MAPK信号通路有关。     

GDF15表达下调促进人胶质母细胞瘤细胞系U87MG增殖

目的探讨生长分化因子15(GDF15)表达下调对人胶质母细胞瘤U87MG细胞系增殖的影响。方法选取稳定下调GDF15的人胶质母细胞瘤U87MG细胞作为shGDF15组,以scramble细胞作为对照组。Western blot检测GDF15蛋白表达;增殖曲线和BrdU掺入实验检测细胞增殖;Western blot检测ERK1/2和p-ERK1/2蛋白表达;CCK-8实验检测细胞增殖。结果与scramble组相比较,shGDF15组细胞增殖明显加快(P0.05);细胞周期S期DNA合成增加(P0.01);ERK通路激活水平明显增加(P0.05);对化疗药物VM-26的耐受性明显增强(P0.05),并且ERK通路抑制剂可降低GDF15表达下调促进细胞增殖作用。结论GDF15可通过下调ERK通路抑制人胶质母细胞瘤U87MG细胞S期DNA合成及细胞增殖,可作为提高胶质瘤临床化疗敏感性的潜在靶点。     

乳腺癌细胞过表达HER2/neu时经PI3K和Ras/Raf/MEK/ERK信号通路下调野生型p53蛋白含量

目的 研究HER2/neu基因过表达对乳腺癌细胞野生型p53蛋白含量的影响并探讨其分子机制。方法 脂质体介导的HER2/neu基因转染MCF7细胞,G418筛选阳性克隆。Western印迹法鉴定HER2/neu蛋白表达,并同时检测p53及信号转导分子Akt,p-Akt,p-Raf,p-MEK,p-ERK蛋白含量,以及P13K信号通路抑制剂LY294002和MEK抑制剂U0126处理对p53蛋白含量的影响。逆转录-聚合酶链反应(RT-PCR)检测p53 mRNA水平。结果 成功建立稳定过表达HER2/neu的MCF7细胞(MCF7-neu3),其HER2/neu蛋白表达量是对照组MCF7细胞的13倍。MCF7-neu3中p-Akt,p-Raf,p-MEK,P-ERK蛋白含量分别较MCF7细胞升高了2.5倍、2倍、1.6倍和1.6倍(P<0.01),p53蛋白含量仅为对照组细胞的40％(P<0.01),但p53mRNA表达无明显差异。在经PI3K信号通路抑制剂LY294002及MEK抑制剂U0126处理24 h后,MCF7-neu3细胞p53蛋白含量分别上升了1.7和1.5倍(P<0.01),在LY294002和U0126处理48 h后,p53蛋白含量分别升高了4.7倍和5.3倍(P<0.01)。LY294002和U0126处理对MDA-MB-453细胞突变型p53蛋白含量不产生影响。结论 乳腺癌细胞中HER2/neu基因的过表达能够通过激活P13K和Ras/Raf/MEK/ERK通路导致野生型p53蛋白含量减少,可能是HER2/neu过表达乳腺癌患者预后不良及对治疗产生抗性的分子机制。     

布托啡诺调控PBX3基因抑制乳腺癌细胞系MCF7增殖、迁移和侵袭

目的探讨布托啡诺(butorphanol)对乳腺癌细胞增殖、迁移和侵袭的影响以及相关的分子机制。方法用MTT法检测不同浓度布托啡诺对人乳腺癌细胞系MCF7的抑制作用;用Transwell迁移及侵袭实验检测不同浓度布托啡诺对人乳腺癌MCF7细胞迁移及侵袭的影响;RT-qCR与Western blot法分别检测乳腺癌细胞系、正常乳腺上皮细胞以及布托啡诺对MCF7细胞中PBX3 mRNA及蛋白表达的影响;观察转染si-PBX3或si-con后,MCF7细胞增殖、迁移及侵袭能力的变化;PBX3过表达验证布托啡诺对乳腺癌增殖、迁移及侵袭的作用机制。Western blot检测cyclin D1和MMP-2蛋白表达。结果PBX3在乳腺癌细胞系中的表达上调,沉默PBX3表达可明显抑制MCF7细胞增殖、迁移及侵袭,同时抑制cyclin D1和MMP-2的表达;不同浓度的布托啡诺干预能显著抑制MCF7细胞增殖、迁移及侵袭且具有浓度依赖性,还可抑制PBX3、cyclin D1和MMP-2的表达;过表达PBX3可逆转布托啡诺对乳腺癌细胞增殖、迁移及侵袭的抑制作用。结论布托啡诺可通过抑制PBX3降低乳腺癌细胞增殖、迁移及侵袭能力。     

ERK1/2信号通路参与瘦素促人γδT细胞增殖调控

为探讨ERK1/2信号通路在瘦素促进人γδT细胞增殖中的作用机制。我们用MTT法观察不同浓度瘦素促γδT细胞的增殖效应,以及用ERK1/2特异性抑制剂PD98059阻断ERK1/2信号通路对瘦素促细胞增殖效应的影响,Western blot法检测瘦素干预对ERK1/2、P-ERK1/2蛋白表达水平的影响。结果显示,瘦素在一定浓度范围内促进人γδT细胞增殖。瘦素可使ERK1/2信号通路中的靶蛋白发生磷酸化激活,用PD98059阻断ERK1/2信号通路可显著抑制瘦素促细胞的增殖效应,亦可抑制瘦素对γδT细胞ERK1/2蛋白磷酸化。因此,我们认为瘦素促人γδT细胞增殖效应可能与激活ERK1/2信号通路有关。     

ERK1/2MAPK通路在Eca109细胞体外增殖和迁移中的作用及其机制

目的观察ERK1/2 MAPK通路在食管鳞状细胞癌(ESCC)Eca109细胞系增殖和迁移中的作用并探讨其作用机制。方法使用MAPK(ERK1/2)抑制剂U0126处理Eca109细胞;细胞计数检测细胞增殖;倒置显微镜下观察细胞形态;实时荧光定量PCR(qRT-PCR)检测ERK1/2 mRNA;Western blot检测总ERK1/2(t-ERK1/2)和磷酸化ERK1/2(p-ERK1/2);MTT和细胞划痕实验检测细胞增殖和迁移能力;qRT-PCR检测MicroRNA-21(miR-21)。结果20μmol/L浓度的U0126可抑制Eca109细胞生长(P<0.05),破坏细胞正常形态,ERK1/2 MAPK通路的活化在蛋白质水平被抑制(P<0.05),Eca109细胞增殖和迁移明显减弱(P<0.05),显著下调miR-21的表达(P<0.05)。结论ERK1/2 MAPK信号通路抑制可减弱Eca109细胞增殖和迁移,其可能的作用机制之一与其抑制miR-21表达有关。     

ERK signalling in metastatic human MDA-MB-231 breast carcinoma cells is adapted to obtain high urokinase expression and rapid cell proliferation

Increased urokinase plasminogen activator (u-PA) production is associated with tumor invasion and metastasis in several malignancies, including breast cancer. The mechanisms underlying constitutive u-PA expression are not well understood. We examined the relationship between the signal strength of the ERK pathway and the level of u-PA expression in the metastatic human breast cancer cell line MDA-MB-231. Treatment with the MEK1 inhibitor PD98059 resulted in decreased ERK1/2 phosphorylation and decreased u-PA mRNA and protein expression. Inhibition of ERK1/2 activity also led to decreased cell proliferation and to decreased cyclin D1 expression. Less than 5% of total ERK1/2 was phosphorylated in exponentially growing MDA-MB-231 cells, and ERK1/2 activity could be stimulated by okadaic acid. Okadaic acid did not stimulate u-PA expression, but induced strong expression of the cdk-inhibitor p21Cip1. These findings suggest that ERK1/2 signaling is tuned to a level which results in high u-PA expression and rapid cell proliferation. This revised version was published online in July 2006 with corrections to the Cover Date.     

Elevated NRD1 metalloprotease expression plays a role in breast cancer growth and proliferation

Understanding the molecular etiology of cancer and increasing the number of drugs and their targets are critical to cancer management. In our attempt to unravel novel breast‐cancer associated proteins, we previously conducted protein expression profiling of the MCF10AT model, which comprises a series of isogenic cell lines that mimic different stages of breast cancer progression. NRD1 expression was found to increase during breast cancer progression. Here, we attempted to confirm the relevance of NRD1 in clinical breast cancer and understand the functional role and mechanism of NRD1 in breast cancer cells. Immunohistochemistry data show that NRD1 expression was elevated in ductal carcinoma in situ and invasive ductal carcinomas compared with normal tissues in 30% of the 26 matched cases studied. Examination of NRD1 expression in tissue microarray comprising >100 carcinomas and subsequent correlation with clinical data revealed that NRD1 expression was significantly associated with tumor size, grade, and nodal status (P < 0.05). Silencing of NRD1 reduced MCF10CA1h and MDA‐MD‐231 breast‐cancer‐cell proliferation and growth. Probing the oncogenic EGF signaling pathways revealed that NRD1 knock down did not affect overall downstream tyrosine phosphorylation cascades including AKT and MAPK activation. Instead, silencing of NRD1 resulted in a reduction of overall cyclin D1 expression, a reduction of EGF‐induced increase in cyclin D1 expression and an increase in apoptotic cell population compared with control cells. © 2011 Wiley‐Liss, Inc.     

Effects of trichostatin A, a histone deacetylase inhibitor, on the regulation of apoptosis in H-ras-transformed breast epithelial cells

This study examined the mechanism for the anti-cancer effects of histone deacetylase (HDAC) inhibitor trichostatin A (TsA) in H-ras-transformed human breast epithelial (MCF10A-ras) cells. The effects of TsA on anti-cancer effects of MCF10A-ras cells were determined by measuring the level of cell cycle regulator expression and apoptotic cell death using Western blotting and flow cytometry analysis, respectively. TsA induced morphological changes, apoptotic cell death and modulation of the cell cycle regulatory proteins in the MCF10A-ras cells. TsA increased the levels of acetylated histone H3 and H4 in MCF10A-ras cells. In addition, TsA markedly down-regulated the expression of cyclin D1 and CDK4, up-regulated the expression of p21WAF1 and p53 and induced cell cycle arrest at the G1 phase in MCF10A-ras cells. The levels of hyperphosphorylation of the Rb protein were lower in MCF10A-ras cells after the TsA treatment. Furthermore, the up-regulation of p53 promoted Bax expression, which led to the activation of pro-caspase-3 and eventually to apoptosis in MCF10A-ras cells. TsA significantly increased the levels of ERK1/2 phosphorylation in MCF10A-ras cells. Overall, the TsA-activated ERK pathway plays an important role in cell cycle arrest and apoptosis through the ERK-dependent induction of p21 in Ras-related human cancer cells.     

Effects of apicidin, a histone deacetylase inhibitor, on the regulation of apoptosis in H-ras-transformed breast epithelial cells

The cellular susceptibility of cancer cells to histone deacetylase (HDAC) inhibitors is increased by the etopic expression of oncogenic Ras. However, the ability of HDAC inhibitors to regulate the apoptotic pathway in human breast cancer cells is still not completely understood. In this study, the anti-proliferative effects of apicidin were compared in H-ras-transformed human breast epithelial (MCF10A-ras) and non-transformed epithelial (MCF10A) cells. MCF10A-ras cells showed a significantly higher growth rate than MCF10A cells. Apicidin significantly increased the levels of acetylated histone H3 and H4 in both cell lines. Western blot analysis and flow cytometry were used to determine if the anti-proliferative effects of apicidin in MCF10A and MCF10A-ras cells could be mediated by modulating the cell cycle. Apicidin attenuated the expression of cyclin E and CDK2 in MCF10A cells, decreased cyclin D1 and cyclin E levels in MCF10A-ras cells, and increased the levels of CDK inhibitors, p21WAF1/Cip1 and p27Kip1, in both cell lines. Notably, the levels of hyperphosphorylation of the Rb protein levels were lower in the MCF10A-ras cells after apicidin treatment. Studies on the regulation of apoptosis showed that apicidin induces the up-regulation of p53 and the downstream activation of ERK in MCF10A-ras cells. The up-regulation of p53 promoted Bax expression leading to activation of caspases-9 and -6, and eventually to apoptosis in MCF10A-ras cells. In addition, apicidin significantly increased the levels of ERK1/2 phosphorylation in MCF10A-ras cells. Therefore, the apicidin-mediated ERK pathway appears to play an important role in modulating the pro-apoptotic pathway in MCF10A-ras cells.     

促性腺激素释放激素类似物对人乳腺癌细胞的影响

目的:探讨促性腺激素释放激素(gonadotropin-releasing hormone,GnRH)类似物曲普瑞林(triptorelin)对人乳腺癌细胞株MCF-7、MDA-MB-231细胞生长及细胞外信号调节蛋白激酶(extracellular signal-regulated kinase,ERK)/丝裂原活化蛋白激酶(mitogen-activated protein kinases,MAPK)和磷脂酰肌醇-3-激酶(phosphatidylinositol-3-kinase,PI3K)/蛋白激酶B(protein kinase B,Akt)信号通路中重要信号分子ERK1/2和Akt活化的影响。方法:使用不同浓度、不同时间的曲普瑞林刺激人乳腺癌MCF-7及MDA-MB-231细胞株,MTT法检测细胞增殖,流式细胞术检测细胞周期的分布,Western blotting检测Akt和ERK1/2的磷酸化程度。结果:曲普瑞林(10-5mol/L)作用人乳腺癌MCF-7细胞192 h、曲普瑞林(10-4mol/L)作用人乳腺癌MCF-7细胞168 h、192 h或曲普瑞林(10-4mol/L)作用人乳腺癌MDA-MB-231细胞192 h可明显抑制细胞生长(P0.05);曲普瑞林(10-4mol/L)作用人乳腺癌MCF-7和MDA-MB-231细胞192 h,ERK1/2的磷酸化程度均较正常对照组低,Akt的磷酸化程度较正常对照组高,但差异无统计学意义(P0.05)。结论:GnRH类似物曲普瑞林对人乳腺癌细胞的抑制作用,不仅仅是通过对垂体激素的降调节机制,还可能产生直接抑制作用。但该抑制作用未涉及ERK/MAPK和PI3K/Akt信号通路。     

IGFBP7对人乳腺癌MCF-7细胞增殖的影响及其机制

目的: 探究胰岛素样生长因子结合蛋白7(IGFBP7)对人乳腺癌MCF-7细胞增殖的影响及其分子生物学机制。方法: 将质粒pCMV6-IGFBP7转染MCF-7细胞,构建稳定表达IGFBP7的MCF-7细胞系;采用Western blotting检测IGFBP7在MCF-7细胞稳定转染子的表达;采用软琼脂培养克隆形成实验检测IGFBP7对MCF-7细胞克隆形成能力的影响;采用流式细胞术检测IGFBP7对MCF-7细胞周期的影响;采用Western blotting检测IGFBP7对MCF-7细胞细胞外信号调节激酶1/2(ERK1/2)、p-ERK1/2、细胞周期素D1(cyclin D1)、细胞周期素依赖性激酶4(CDK4)、cyclin E、CDK2、p21^CIP1/WAF1、p27^KIP1、p53、视网膜母细胞瘤蛋白(Rb)和p-Rb蛋白含量的影响。结果: (1)只有稳定转染质粒pCMV6-IGFBP7的MCF-7细胞表达IGFBP7。(2)IGFBP7能够显著降低MCF-7细胞的克隆形成率(P<0.01),阻止细胞从G₁期进入S 期,使其停滞于G₁期(P<0.01)。(3)IGFBP7能够显著抑制ERK1/2的磷酸化(P<0.01)。(4)IGFBP7能够下调cyclin D1和cyclin E蛋白表达(P<0.01),上调p27^KIP1、p21^CIP1/WAF1和p53蛋白表达(P<0.01),抑制Rb的磷酸化(P<0.01)。(5)MEK1/2阻断剂PD98059可部分模拟IGFBP7的肿瘤抑制效应。结论: (1) IGFBP7可通过下调cyclin D1和cyclin E蛋白表达,上调p27^KIP1、p21^CIP1/WAF1和p53蛋白表达,以及抑制Rb磷酸化发挥抗肿瘤作用;(2) IGFBP7对cyclin D1和p27^KIP1的调节可能与其抑制ERK1/2信号通路有关。     

乳腺癌发生模型MCF10各细胞系中WT1基因启动子区甲基化及mRNA表达研究

目的通过观察乳腺癌发生模型MCF10中WT1基因启动子区甲基化状态和mRNA表达水平,探讨该基因在乳腺癌发生中的作用。方法应用甲基化特异性PCR及双亚硫酸钠基因测序技术检测MCF10模型的乳腺增生细胞系MCF10A、癌前细胞系MCF10AT、导管内癌细胞系MCF10DCIS．com、浸润癌细胞系（MCF10CAla、MCF10CA1d、MCF10CA1h）、经典乳腺癌细胞系MCF7及正常乳腺组织中WT1基因启动子区甲基化状态,然后用逆转录．聚合酶链反应（RT—PCR）和即时定量PCR技术检测上述样品的mRNA表达水平。结果在MCF10模型的增生细胞系MCF10A、癌前细胞系MCF10AT、导管内癌细胞系MCF10DCIS．com、浸润癌细胞系（MCF10CAla、MCF10CA1d、MCF10CA1h）、经典乳腺癌细胞系MCF7中,WT1基因启动子均处于高度甲基化状态。与正常乳腺组织相比,WT1基因mRNA在MCFl0模型的增生细胞系、癌前细胞系、导管内癌细胞系、浸润癌细胞系和经典乳腺癌细胞系MCF7中的表达均有不同程度的增加（MCF10A、MCF10AT、MCF10CAla、MCF10CA1d、MCF10CA1h、MCF10DCIS、MCF7的WT1基因mRNA表达量分别是正常乳腺组织3．23、1．94、4．20、1．53、4．20、4．35、28．69倍）。结论乳腺癌发生过程中WnmRNA的表达不被启动子甲基化所抑制;可WT1mRNA过表达出现于乳腺癌发生的早期阶段,提示该基因在乳腺癌发生中起作用。     

C/EBPα inhibits proliferation of breast cancer cells via a novel pathway of miR-134/CREB

C/EBPα plays an important role in the modulation of cell proliferation, differentiation or apoptosis in various tissues. Most recently, reduced expression of C/EBPα and growth inhibitory effect was found in primary mammary carcinomas. However, the underlying mechanism is still not fully aware. Here, we firstly identified miR-134 as a target of C/EBPα in MCF7 breast cancer cell lines. C/EBPα overexpression promoted miR-134 expression, causing suppression of apoptosis- protective genes CREB and Bcl-2, and resulted in the proliferation inhibition of MCF7 cells. Moreover, anti-miR-134 rescued the proliferation inhibition of MCF7 cells and the suppression of anti-apoptotic genes CREB and Bcl-2 caused by C/EBPα overexpression. Collectively, C/EBPα inhibited cell growth in breast cancer cells via a novel pathway miR-134/CREB.