癌基因B-RafV600E导致黑色素瘤Sbcl2和SK-MEL31细胞染色体不稳定性的分子机制研究

目的 研究癌基因B-RafV600E导致肿瘤细胞染色体不稳定的分子机制.方法 采用RNA干扰技术敲除稳定表达B-RafV600E基因的黑色素瘤Sbcl2和SK-MEL31细胞中内源性单核纺锤体蛋白激酶(Mps1)基因表达,免疫荧光染色技术检测中心体及纺锤体结构.HU-arrest分析法观察Mps1基因缺失对癌基因B-RafV600E致肿瘤细胞中心体过度复制及多极纺锤体形成的影响.结果 未敲除内源性Mps1基因的表达B-RafV600E基因的Sbcl2和SK-MEL31细胞中36％出现中心体过度复制及多极纺锤体,Mps1基因被敲除后上述异常细胞比例降低至6％.结论 B-RafV600E可能通过Mps1调控中心体过度复制及多极纺锤体结构的形成,影响肿瘤细胞染色体不稳定性及非整倍体细胞的出现.     

ERK1/2-Sp1信号通路对肺癌细胞VEGF的调控作用

背景与目的:了解ERK1/2-Sp1信号通路对肺癌细胞血管内皮生长因子(VEGF)基因的调控作用.材料与方法:采用激酶特异抑制剂PD98059抑制ERK1/2的活性,Western blot检测ERK1/2的表达.RNA干扰技术沉默Sp1基因,Mercury信号通路系统检测Sp1的转录活性.RT-PCR检测VEGF和Sp1基因的变化. 结果:ERK1/2激酶的活性几乎可被150μmol/L PD98059完全抑制,ERK1/2激酶活性下调伴随VEGF的表达下降.PD98059下调Sp1转录因子的活性.Sp1基因沉默后VEGF的表达量下调. 结论:在肺癌细胞中存在ERK1/2-Sp1-VEGF信号通路,ERK1/2激酶调控VEGF的表达可能部分依赖于转录因子Sp1的活性.     

ERK1/2通路基因突变对低级浆液性卵巢癌发生发展的影响

卵巢癌是女性生殖器官中常见的恶性肿瘤之一,是女性生殖系统肿瘤中的最大杀手.随着分子遗传学和肿瘤生物学研究的深入发展,基因诊断已成为治疗恶性肿瘤的重要手段.因此,研究卵巢癌的分子遗传学机制进而了解其生物学效应对卵巢癌的发生发展、治疗及预后等方面有重要意义.大量临床病理学和分子遗传学实验证明ERK1/2通路异常活动与低级浆液性卵巢癌的发生发展关系密切.文章将针对ERK1/2通路的异常持续活化(KRAS或BRAF突变次级效应)与低级浆液性卵巢癌发生发展的关联性研究作一简要综述.     

TGF-β1在乳腺癌EMT中作用机制探讨

目的 乳腺癌的发病率不断上升,上皮-间质转化(epithelial to mesenchymal transition,EMT)在乳腺癌病变中广泛存在.本研究探讨TGF-β1在乳腺癌EMT中的作用及PTPN12在此过程中的作用和相关机制.方法 蛋白质印迹法检测TGF-β1处理乳腺癌细胞后EMT相关基因以及PI3K、p-AKT和mTOR的表达;免疫组织化学检测乳腺癌组织和癌旁组织中PTPN 12表达;免疫共沉淀检测PTPN12和p-AKT是否有直接相互作用;蛋白质印迹法检测转染LV5-PTPN12后,E-Cadherin、Vimentin、Fibronectin、PI3K、p-AKT和mTOR蛋白的表达情况;裸鼠皮下成瘤检测PT-PN12对乳腺癌成瘤大小以及体积的影响.结果 NC组和TGF-β1组Vimentin蛋白表达量分别为(17.2±2.3)％和(79.7±8.3)％,t=12.5,P=0.008;Fibronectin蛋白表达量分别(17.4±2.3)％和(77.4±7.5)％,t=12.1,P=0.016.PTPN12在乳腺癌组织中表达明显降低,PTPN12与乳腺癌病理分期分级以及腋窝淋巴结受累数目有关,NC组和TGF-β1组PI3K蛋白表达量分别为(18.6±1.9)％和(76.3±5.9)％,t=12.1,P=0.029;p-AKT蛋白表达量分别为(27.6±3.2)％和(54.1±6.2)％,t=11.7,P=0.013;mTOR蛋白表达量分别为(35.2±3.2)％和(72.2±5.3)％,t=18.3,P=0.031;PTPN12和p-AKT有直接相互作用;PTPN12可以抑制TGF-β1诱导的EMT,LV5-PTPN12组和LV5-NC组Vimentin蛋白表达量分别为(17.2±2.3)％和(79.7±8.3)％,t=11.9,P＜0.018;Fibronectin蛋白表达量分别为(17.4±2.3)％和(77.4±7.5)％,t=10.2,P=0.019;E-Cadherin蛋白表达量分别为(82.1±8.4)％和(0.22±0.02)％,t=13.7,P＜0.001.PTPN12可以通过PI3K/AKT信号通路起作用,LV5-PTPN12组和LV5-NC组PI3K蛋白表达量分别为(13.2±1.2)％和(56.2±5.1)％,t=7.1,P=0.021;p-AKT蛋白表达量分别为(23.5±2.5)％和(77.1±6.3)％,t=9.2,P=0.008;mTOR蛋白表达量分别为(28.2±3.1)％和(71.7±6.1)％,t=12.8,P=0.032.体内实验表明,与对照组相比,LV5-PTPN12组荷瘤小鼠肿瘤体积和体质量都明显变小,LV5-PTPN12组和LV5-NC组肿瘤体积分别为(2.8±0.2)和(0.4±0.02) cm3,t'=13.8,P＜0.001;体质量分别为(3.1±0.3)和(0.4±0.02)g,t'=18.6,P＜0.001.结论 PTPN12在TGF-β1作用下通过PI3K/AKT信号通路诱导乳腺癌的EMT中起抑制作用.     

Glypican-6在胃肠道间质瘤组织中的表达及其通过ERK1/2通路促进细胞的增殖、迁移及侵袭

目的:探究Glypican-6对胃肠道间质瘤的作用及其可能的作用机制.方法:收集胃肠道间质瘤组织及其癌旁组织27例,RT-PCR和Western blot检测组织中Glypican-6的表达.选取胃肠道间质瘤细胞系GIST-T1进行体外研究.RT-PCR实验检测细胞中Glypican-6 mRNA的表达;Western...     

干扰小RNA沉默CAV1表达对人绒毛膜癌JEG-3细胞侵袭、迁移能力的影响及其作用机制研究

目的 探究干扰小RNA(siRNA)沉默小窝蛋白-1(CAV1)基因表达对人绒毛膜癌JEG-3细胞侵袭、迁移能力的影响及其可能的作用机制.方法 将人绒毛膜癌JEG-3细胞分为对照组(不进行转染)、阴性组(转染siRNA-NC)和siRNA-CAV1组(转染siRNA-CAV1).Transwell法检测下调CAV1表达对细胞侵袭、迁移能力的影响;实时定量PCR(qRT-PCR)检测转染细胞中CAV1 mRNA的表达水平;蛋白质印迹法(Western blot)检测细胞中CAV1、丝苏氨酸蛋白激酶(AKT)、雷帕霉素靶蛋白(MTOR)、核糖体p70S6激酶(p70S6K)、磷酸化AKT(p-AKT)、磷酸化MTOR(p-MTOR)、磷酸化p70S6K(p-p70S6K)蛋白的表达水平.结果 siRNA-CAV1组JEG-3细胞中CAV1 mRNA和蛋白的相对表达量均低于对照组(P﹤0.05);siRNA-CAV1组JEG-3细胞的侵袭数目、迁移数目均低于对照组(P﹤0.05);siRNA-CAV1组JEG-3细胞中AKT、MTOR、p70S6K以及磷酸化水平均低于对照组(P﹤0.05).结论 沉默CAV1表达可以抑制人绒毛膜癌JEG-3细胞的侵袭和迁移能力,该作用与AKT/MTOR/p70S6K信号通路有关.     

过氧化物氧化还原酶蛋白1在乳腺癌组织中表达及对乳腺癌细胞生长调控机制的研究

目的 探讨过氧化物氧化还原酶蛋白1(PRDX1)在乳腺癌组织中的表达及对乳腺癌细胞生长调控的机制.方法 选择2017年4月至2019年2月在北大医疗鲁中医院进行手术治疗的86例乳腺癌患者为研究对象,分析PRDX1表达与乳腺癌患者临床病理特征的关系.培养MCF7乳腺癌细胞株,分组转染成空白对照组、siRNA-NC组、PR...     

乳腺癌中DKKL1的表达、作用及机制探讨

目的:研究Dickkopf样蛋白1(dickkopf-like protein 1,DKKL1)基因在乳腺癌组织和细胞系中的表达水平,探讨DKKL1基因过表达对人乳腺癌MDA-MB-231和MCF-7细胞增殖、迁移的影响及其分子作用机制.方法:采用实时荧光定量PCR检测乳腺癌细胞系、80例人乳腺癌和癌旁组织以及20例正...     

siRNA靶向沉默MALAT-1对鼻咽癌细胞增殖、凋亡及PI3K/AKT通路的影响

目的:探究siRNA靶向沉默MALAT-1对鼻咽癌细胞增殖、凋亡及PI3K/AKT通路的影响。方法:分别以10、20、30、40、50 nmol/L浓度的siRNA靶向沉默体外培养的人鼻咽癌细胞株CNE的基因MALAT-1,以实时荧光定量（qRT-PCR）分别在24、48 h后检测MALAT-1 mRNA表达水平,筛选合适的siRNA作用浓度和时间。将CNE细胞分为三组:空白对照组、siRNA阴性对照组和siRNA组,siRNA处理细胞后,采用CCK-8法检测细胞增殖情况,采用流式细胞技术检测细胞凋亡情况,Western blot 检测各组细胞凋亡相关蛋白（Bcl-2、Bax、caspase-3）及PI3K/AKT通路蛋白（PI3K、ATK、p-AKT）表达情况。结果:选定30 nmol/L浓度的siRNA作用于CNE细胞48 h;siRNA处理细胞后,与空白对照组相比,siRNA组细胞增殖率明显降低,凋亡率明显升高,Bax、caspase-3蛋白表达明显升高,Bcl-2、PI3K、p-AKT蛋白表达明显降低,差异均有统计学意义（P＜0.05）;AKT蛋白表达无明显变化,差异无统计学意义（P＞0.05）。siRNA阴性对照组各指标均无明显变化,差异无统计学意义（P＞0.05）。结论:siRNA可靶向沉默MALAT-1,抑制鼻咽癌细胞增殖,促进其凋亡,可能是通过抑制PI3K/AKT通路实现的。     

lncRNA TFAP2A-AS1/miR-9-5p通过ERK通路对子宫内膜癌细胞增殖、侵袭及迁移的影响

目的:探讨长链非编码RNA TFAP2A-AS1对子宫内膜癌细胞增殖、侵袭和迁移的影响及机制。方法:选择50例子宫内膜癌组织和对应的癌旁组织。选取子宫内膜癌细胞株(RL95-2、HEC-1A、HHUA、HEC-1B及Ishikawa),子宫内膜上皮细胞hEEC。子宫内膜癌细胞株Ishikawa转染si-TFAP2A-AS1(si-TFAP2A-AS1组)、si-NC(si-NC组)、miR-9-5p mimics(miR-9-5p组)及miR-NC(miR-NC组);RL95-2细胞转染OE-TFAP2A-AS1(TFAP2A-AS1组)、Vector(Vector组)、sh-miR-9-5p(sh-miR-9-5p组)及sh-NC(sh-NC组)。CCK-8检测细胞增殖能力,Transwell检测细胞侵袭、迁移能力,双荧光素酶实验、pull down实验分析TFAP2A-AS1与miR-9-5p的靶向关系;miR-9-5p与ERK的靶向关系,实时荧光定量PCR(RT-qPCR)检测子宫内膜癌组织、癌旁组织、子宫内膜癌细胞及hEEC细胞TFAP2AAS1、miR-9-5p表达水平,We...     

Oncogenic B-Raf abrogates the AKT/B-Raf/Mps1 interaction in melanoma cells

Activating B-Raf mutations that deregulate the mitogen-activated protein kinase (MAPK) pathway commonly occur in cancer. Although B-Raf^V600E induces increased Mps1 protein contributing to centrosome amplification and chromosome instability, the regulatory mechanisms of Mps1 in melanoma cells is not fully understood. Here, we report that Mps1/AKT and B-Raf^WT/ERK signaling form an auto-regulatory negative feedback loop in melanoma cells; notably, oncogenic B-Raf^V600E abrogates the negative feedback loop, contributing the aberrant Mps1 functions and tumorigenesis. Our findings raise the possibility that targeting the oncogenic B-Raf and Mps1, especially when used in combination could potentially provide great therapeutic opportunities for cancer treatment.     

ERK1/2 MAPK在赖氨匹林对MCF-7细胞增殖抑制中的作用

背景与目的:探讨赖氨匹林(Aspisol)在抑制人乳腺癌MCF-7细胞增殖过程中,对ERK1/2 MAPK信号转导通路的影响.材料与方法:采用免疫细胞化学方法测定MCF-7细胞中环氧合酶-2(COX-2)的表达.采用噻唑蓝(MTY)比色法检测Aspisol对MCF-7增殖的抑制作用;采用流式细胞仪检测细胞凋亡情况;应用Western blot分别检测ERKl/2、p-ERK]/2蛋白和凋亡相关蛋白Bcl-2、Bax的表达.结果:在MCF-7细胞中未检测到COX-2的表达.Aspisol对MCF-7细胞增殖有明显的抑制作用,且具有剂量和时间依赖性(P＜0.01).Aspisol可诱导MCF-7细胞凋亡,并随着剂量的增大细胞的凋亡率升高(P＜0.05).Aspisol抑制MCF-7细胞pERK蛋白的表达(P＜0.05),但不影响总ERKI/2蛋白的表达(P＞0.05);Aspisol可促进Bax蛋白表达(P＜0.05),但抑制Beb2的表达(P＜0.05).结论:Aspisol影响ERKI/2 MAPK信号转导通路,调节凋亡相关蛋白表达是其抑制MCF-7细胞增殖的作用之一.     

沉默MCM7基因介导AKT信号通路参与黑色素瘤细胞增殖及凋亡的实验

目的 探讨MCM7基因沉默介导AKT信号通路参与人皮肤黑色素瘤细胞的增殖及凋亡。方法 构建MCM7基因和沉默MCM7基因表达的慢病毒RNA（LV-shRNA-MCM7）的表达载体;将A375细胞分为Control组、Empty vector转染组（空载质粒转染组）、siRNA（LV-shRNA-MCM7）转染组、siRNA NC（LV-shRNA-MCM7 negative control）转染组;MTT法检测每组细胞增殖;流式细胞术检测细胞周期、细胞凋亡情况;划痕实验法检测细胞迁移能力;qRT-PCR法测定细胞中MCM7基因、AKT信号通路相关基因、Cyclin D1及凋亡相关基因Bcl-2、Bax、caspase-3的相对表达量;Western blot法测定蛋白相对表达量。结果 沉默MCM7后,黑色素瘤细胞中的MCM7基因、CyclinD1、Bcl-2、AKT信号通路相关基因AKT3的mRNA和蛋白相对表达量显著下调（P<0.05）;凋亡相关基因Bax、caspase-3的mRNA和蛋白表达量显著上调（P<0.05）;siRNA转染组凋亡率显著上升,G₀/G₁期细胞数目明显增多,S期细胞数目明显减少;细胞增殖、迁移能力显著下降（P<0.05）。结论 沉默MCM7基因抑制AKT信号通路的激活,从而抑制A375黑色素瘤细胞增殖、迁移,促进A375黑色素瘤细胞凋亡。     

Dual inhibition of (V600E)BRAF and the PI3K/AKT/mTOR pathway cooperates to induce apoptosis in melanoma cells through a MEK-independent mechanism

BRAF is a main oncogene in human melanomas. Here, we show that BRAF depletion by siRNA or inhibition of its activity by treatment with RAF inhibitor Sorafenib induces apoptosis in NPA melanoma cells expressing oncogenic ^V600EBRAF. This effect is mediated through a MEK/ERK-independent mechanism, since treatment with the MEK inhibitor U0126 does not exert any effect. Moreover, we demonstrate that inhibition of the PI3K/AKT/mTOR cascade alone does not increase apoptosis in these cells. However, the blockage of this pathway in cells lacking either BRAF expression or activity cooperates to induce higher levels of apoptosis than those achieved by inhibition of BRAF alone. Consistently, we demonstrate that abrogation of BRAF expression increases AKT and mTOR phosphorylation, suggesting the existence of a compensatory pro-survival mechanism after BRAF depletion. Together, our data provide a rationale for dual targeting of BRAF and PI3K/AKT/mTOR signalling to effectively control melanoma disease.     

Simalikalactone E (SkE), a new weapon in the armamentarium of drugs targeting cancers that exhibit constitutive activation of the ERK pathway

Simalikalactone E (SkE) is a quassinoid extracted from a widely used Amazonian antimalarial remedy. Although SkE has previously been shown to have cytostatic and/or cytotoxic activities in some tumor cell lines, its mechanism of action has not yet been characterized. We show here that SkE in the high nanomolar range inhibited the growth of various leukemic and solid tumor cell lines. Importantly, SkE was highly efficient at inhibiting chronic myelogenous leukemia (CML) cells that exhibit constitutive activation of the MAPK pathway and, accordingly, it impaired the phosphorylation of ERK1/2. SkE also abrogated MEK1/2 and B-Raf phosphorylation but had no effect on Ras activity. Moreover, SkE was particularly effective against melanoma cell lines carrying the B-Raf-V600E mutation. Importantly, SkE resensitized the PLX-4032-resistant 451Lu melanoma cell line (451Lu-R) and was more efficient than U0126, a MEK inhibitor, and PLX-4032 (PLX) at inducing the apoptosis of two Hairy Cell Leukemia (HCL) patient samples carrying the B-Raf-V600E mutation. Finally, SkE was as efficient as imatinib at inhibiting tumor formation in a xenograft model of CML cells in athymic mice. In conclusion, we show that SkE, a very potent inhibitor of B-Raf-V600E, is highly effective against cancer cell lines that exhibit constitutive activation of the ERK1/2 pathway.     

沉默CCND1基因表达抑制ERK/MAPK信号通路激活提升宫颈癌化疗敏感性

目的 研究CCND1介导ERK/MAPK信号通路介导宫颈癌化疗敏感性的机制.方法 收集60例宫颈癌及癌旁组织标本,qRT-PCR检测组织中CCND1、ERK和MAPK表达量,免疫组化确认并定位CCND1在组织中的表达.筛选宫颈癌细胞株,将细胞分组为Blank组、pcDNA-CCND1组、pcDNA-CCND1 NC组、...     

HMGB1-mediated autophagy modulates sensitivity of colorectal cancer cells to oxaliplatin via MEK/ERK signaling pathway

In the present study, we examined the mechanisms of oxaliplatin-induced drug resistance in human colorectal cancer cell lines HT29 and HCT116. Our results demonstrate a significant autophagy expression in CRC cells after an oxaliplatin treatment. Administration of oxaliplatin to human CRC cells significantly enhanced the expression of HMGB1, which regulated the autophagy response and negatively regulate the cell apoptosis. Moreover, a decreased oxaliplatin -induced autophagy response and an increased apoptosis level were detected in stable CRC cells harboring HMGB1 shRNA. Then we noted that HMGB1 significantly induced extracellular signal-regulated kinase (ERK)/Extracellular signal-regulated kinase kinase (MEK) phosphorylation. Taken together, these data suggest that HMGB1-mediated autophagy modulates sensitivity of colorectal cancer cells to oxaliplatin via MEK/ERK signaling pathway.     

RNAi‐mediated MEK1 knock‐down prevents ERK1/2 activation and abolishes human hepatocarcinoma growth in vitro and in vivo

The mitogen‐activated protein kinases MEK/ERK pathway regulates fundamental processes in malignant cells and represents an attractive target in the development of new cancer treatments especially for human hepatocarcinoma highly resistant to chemotherapy. Although gene extinction experiments have suggested distinct roles for these proteins, the MEK/ERK cascade remains widely considered as exhibiting an overlap of functions. To investigate the functionality of each kinase in tumorigenesis, we have generated stably knock‐down clones for MEK1/2 and ERK1/2 isoforms in the human hepatocellular carcinoma line HuH7. Our results have shown that RNAi strategy allows a specific disruption of the targeted kinases and argued for the critical function of MEK1 in liver tumor growth. Transient and stable extinction experiments demonstrated that MEK1 isoform acts as a major element in the signal transduction by phosphorylating ERK1 and ERK2 after growth factors stimulation, whereas oncogenic level of ERK1/2 phosphorylation appears to be MEK1 and MEK2 dependent in basal condition. In addition, silencing of MEK1 or ERK2 abolished cell proliferation and DNA replication in vitro as well as tumor growth in vivo after injection in rodent. In contrast, targeting MEK2 or ERK1 had no effect on hepatocarcinoma progression. These results strongly corroborate the relevance of targeting the MEK cascade as attested by pharmacologic drugs and support the potential application of RNAi in future development of more effective cancer therapies. Our study emphasizes the importance of the MEK/ERK pathway in human hepatocarcinoma cell growth and argues for a crucial role of MEK1 and ERK2 in this regulation.