p70S6K1及4E-BP1蛋白在结直肠癌中的作用

磷脂酰肌醇激酶3-蛋白激酶 B-雷帕霉素靶蛋白（mTOR）信号通路在结直肠癌的发生、发展中发挥重要的作用。mTORC1下游靶点是核糖体 S6蛋白激酶1（p70S6K1）和真核翻译起始因子-4E结合蛋白1（4EBP1）,两者在蛋白质合成中起主要的调节作用。结直肠癌中 p70S6K1及4EBP1的异常表达成为关注的焦点。     

mTOR信号通路蛋白在人脑胶质瘤中的表达及其临床意义

目的:研究哺乳动物雷帕霉素靶蛋白(mammalian target of rapamycin,mTOR)信号通路蛋白在人脑胶质瘤中的表达及其临床意义。方法:选取山东大学齐鲁医院和聊城市人民医院神经外科2007年7月至2010年5月间手术切除并经病理证实的人脑胶质瘤石蜡标本87例(Ⅰ～Ⅱ级27例、Ⅲ级24例、Ⅳ级36例),应用免疫组织化学法检测胶质瘤组织中mTOR信号通路关键蛋白pAKT、pmTOR和p-p70S6K的表达,分析它们与胶质瘤患者临床病理特征的关系。结果:pAKT、pmTOR和p-p70S6K在各级胶质瘤中的阳性率分别为:Ⅰ～Ⅱ级70.4%(19/27)、Ⅲ级70.8%(17/24)、Ⅳ级75.0%(27/36),Ⅰ～Ⅱ级77.8%(21/27)、Ⅲ级75.0%(18/24)、Ⅳ级72.2%(26/36),Ⅰ～Ⅱ级63.0%(17/27)、Ⅲ级70.8%(17/24)、Ⅳ级80.6%(29/36);各阳性表达率间无明显差异(P>0.05),但它们的表达水平均随着胶质瘤病理级别的增高而升高(P=0.0001,0.0063,0.0001),而与患者的性别、年龄、肿瘤大小和术前KPS评分等参数无关。pAKT、pmTOR和p-p70S6K三者共表达于42例胶质瘤组织中,在其余45例中仅有一种或两种表达。结论:mTOR信号通路蛋白在胶质瘤的发生、发展中起着重要的作用,可能是胶质瘤治疗的潜在靶点。     

弥漫大B细胞性淋巴瘤中mTOR信号通路的激活

0引言 mTOR(mallmalian target of rapamycin)属于丝/苏氨酸激酶家族,在细胞生长和增殖控制中发挥着关键作用.在上游,生长信号激活的Akt激酶诱导其磷酸化而活化.下游其磷酸化核糖体蛋白S6激酶(S6 kinase,S6K1,p70S6K)而刺激蛋白质翻译和核糖体形成[1-2].近年来研究表明,多种恶性肿瘤中存在mTOR信号通路的激活[1-2],该通路因此被视为癌症靶向治疗的新的潜在靶点.雷帕霉素作为免疫抑制剂首先应用于预防器官移植排异反应的研究,但随后发现其能通过调节mTOR激酶活性,抑制信号通路的激活而对抗细胞的增殖,因此被视为一种潜在的抗肿瘤药物,临床上,其衍生物CCI-779(Temsirolmus)已被批准用于晚期肾细胞癌的治疗.     

新疆维族与汉族乳腺癌组织mTOR及其下游分子4EBPl和S6K1表达差异研究

目的：探讨新疆维吾尔族和汉族乳腺癌组织中哺乳动物雷帕霉素靶蛋白（mammalian target of rapamycin,mTOR）及其下游分子4EBPl和S6K1的表达差异。方法：选取2005—0301—2009—09—30新疆医科大学附属肿瘤医院的维吾尔族和汉族女性浸润性乳腺癌患者285例,使用免疫组化方法检测磷酸化mTOR及其下游分子4EBPl和S6K1的表达状况;分别选取2012—01—01—20120630新疆医科大学附属肿瘤医院63例维、汉新鲜乳腺癌和癌旁组织样本,使用荧光定量RT-PCR法检测mTOR及其下游分子4EBPl和S6K1的mRNA表达状况。结果：免疫组化结果显示,维吾尔族和汉族p-mTOR在乳腺癌组织中的阳性表达率分别为77．1％和67．4％（P=0．067）,在癌旁组织中的阳性表达率分别为57．6％和61．7％（P=0．485）;p-4EBPl在癌组织中的阳性表达率分别为31．9％和20．0％（P=0．020）,在乳腺癌旁组织中的阳性表达率分别是4．9％和12．1％（P=0．029）;p-S6K1在癌组织中的阳性表达率分别为41．0％和43．3％（P=0．695）,在乳腺癌旁组织中的阳性表达率分别为14．0％和22．7％,P=0．054;荧光定量RT—PCR结果显示,维、汉乳腺癌组织中mTORmRNA相对定量结果差异有统计学意义,p=0．045;4EBPl和S6K1mRNA相对定量结果差异无统计学意义,P值分别为0．128和0．404。结论lmTOR信号通路中p-4EBPl的表达水平存在维、汉民族的差异,为研究维、汉不同民族之间乳腺癌差异及个体化治疗提供了进一步研究方向。mTOR及其下游分子mRNA表达水平与磷酸化蛋白的表达并不完全一致,提示蛋白表达的调控位点可能位于转录后水平。     

mTOR、eIF4E、4E-BP1在宫颈癌组织中的表达及临床意义

目的 探讨mTOR、eIF4E、4E-BP1在宫颈癌发生发展中的作用和相关性,为预后判断提供理论依据。方法 采用免疫组织化学SP法检测mTOR、eIF4E、4E-BP1在53例宫颈癌组织、15例宫颈上皮内瘤变组织和13例正常宫颈组织中的表达。结果 (1)mTOR、eIF4E和4E-BP1在宫颈癌组中的阳性表达显著高于正常组和CIN组(P＜0.01),而后两组比较差异无统计学意义(P＞0.05);(2)eIF4E表达与宫颈癌临床分期、淋巴结转移、病理分化程度和术后复发有关(P＜0.01,P＜0.01,P＜0.05,P＜0.05);(3)mTOR表达与宫颈癌术后复发显著相关(P＜0.01);(4)4E-BP1表达与宫颈癌临床分期显著相关(P＜0.01);(5)mTOR与eIF4E;mTOR与4E-BP1在宫颈癌中的阳性表达均呈显著正相关(P＜0.01);(6)生存单因素分析mTOR、eIF4E、4E-BP1均与宫颈癌的预后有关(P＜0.01,P＜0.05,P＜0.05)。结论 mTOR、eIF4E、4E-BP1的高表达在宫颈癌发生发展中起重要作用,与预后不良有关。     

PI3K/Akt/mTOR信号通路抑制剂在乳腺癌中的研究进展

目的:总结PI3K/Akt/mTOR信号通路靶向治疗在乳腺癌中的研究进展.方法:以“PI3K/Akt/mTOR、信号通路和乳腺癌”等为关键词,检索2000-01-2011-06 PubMed、Ovid和Springer等数据库的相关文献.纳入标准:1)关于PI3K/Akt/mTOR信号通路的组成、功能特点;2)PI3K/Akt/mTOR信号通路与乳腺癌的关系研究;3)以PI3K/Akt/mTOR信号通路中关键分子为靶点的乳腺癌治疗.根据纳入标准,符合分析的文献40篇.结果:信号转导通路的异常是肿瘤发生、发展的重要步骤,PI3K/Akt/mTOR信号通路与人类多种肿瘤密切相关,其在肿瘤细胞的增殖、存活、抵抗凋亡、血管发生和转移以及对放化疗抵抗中发挥了重要作用.乳腺癌中常见PI3K/Akt/mTOR信号通路的异常激活,以此通路为靶点的药物已成为乳腺癌治疗的研究热点.结论:靶向PI3K/Akt/mTOR通路中关键分子的众多药物在乳腺癌开展了一系列相关的临床试验研究,一部分显示出较好的安全性和有效性.随着对PI3K/Akt/mTOR通路的分子生物学机制的深入研究,期待靶向此通路的抑制剂将会在乳腺癌治疗中发挥巨大的作用,进一步提高乳腺癌患者的疗效和改善预后.     

P13K／AKT／mTOR信号通路在乳腺癌Her-2治疗耐药中的作用研究进展

Her-2靶向治疗是Her-2过表达乳腺癌治疗的重要组成部分,但Her-2靶向治疗的耐药严重影响了乳腺癌的治疗。研究证实乳腺癌Her-2靶向治疗出现耐药的过程中有P13K／AKT／mTOR信号通路的激活,因此对P13K／AKT／mTOR信号通路及以P13K／AKT／mTOR信号通路为靶点的药物研究对乳腺癌治疗具有重要意义。     

PI3K/AKT/mTOR信号通路抑制剂在淋巴瘤中的研究进展*

磷脂酰肌醇-3 激酶（phosphatidylinositol 3-kinase,PI 3K）- 蛋白激酶B（protein kinaseB ,PKB ,又称AKT ）- 雷帕霉素靶蛋白（mammalian target of  rapamycin,mTOR）信号通路与细胞的生长、增殖、分化、凋亡、代谢等密切相关,在多种实体肿瘤中已发现该信号通路的异常。近年来,以抑制该通路特定位点的靶向治疗已成为抗肿瘤的研究热点。许多该位点新型抑制剂也已进入淋巴瘤的临床试验中,本文就该通路在淋巴瘤中的活化状态及各个分子靶点抑制剂的研究进展做一综述。     

PI3K/AKT/mTOR信号通路在三阴性乳腺癌中的作用及靶向治疗研究进展

摘 要：三阴性乳腺癌（triple negative breast cancer,TNBC）是一种特殊类型的乳腺癌亚型,占所有乳腺癌的15%,具有高度异质性。目前临床上以化疗为主要治疗手段,但效果并不理想。全文主要介绍了TNBC的生物学特点、分子分型和重要相关通路,其中PI3K/AKT/mTOR 信号传导通路在TNBC中尤为重要,该通路上的相关靶点为TNBC提供了更好的精准治疗。     

靶向PI3K/Akt/mTOR通路在胃癌中的研究进展

磷脂肌醇3-激酶(phosphoinositide-3 kinase,PI3K)-蛋白激酶B(protein kinase B,PKB,又称AKT)-雷帕霉素靶蛋白(mammalian target of rapamycin,mTOR)信号通路不仅与细胞的增殖、存活及迁移密切相关,其与肿瘤的发生和发展也具有相关性。近年来,以该通路作为抗肿瘤治疗的靶点已成为研究的热点。本文就胃癌中PI3K/AKT/mTOR信号通路的调节、相关蛋白的表达情况以及针对该通路的靶向药物治疗的研究作综述,并就今后胃癌中该通路可能的研究方向作展望。     

Monepantel induces autophagy in human ovarian cancer cells through disruption of the mTOR/p70S6K signalling pathway

We have recently shown that the novel anthelmintic drug monepantel (MPL) inhibits growth, proliferation and colony formation, arrests the cell cycle and induces cleavage of PARP-1 in ovarian cancer cell lines. Here we report on the mechanism behind the anticancer properties of MPL. The cytotoxic effect of MPL on ovarian cancer cells (OVCAR-3 and A2780) was investigated employing a panel of tests used for the detection of apoptosis and autophagy. Apoptosis and autophagy were defined by caspase activity, DNA-laddering, Annexin-V and acridine orange (AO) staining. Autophagy markers such as LC3B, SQSTM1/p62 and mammalian target of rapamycin (mTOR) pathway related proteins were assessed by western blotting and ELISA techniques. MPL did not activate caspases 3 or 8, nor did it alter the percentage of Annexin V positive stained cells. Failure to cause DNA laddering and the inability of z-VAD-fmk to block the MPL antiproliferative effects led to the ruling out of apoptosis as the mechanism behind MPL-induced cell death. On the other hand, accumulation of acidic vacuoles with distinct chromatin morphology and an increase in punctuate localization of green fluorescent protein-LC3B, and MPL-induced changes in the expression of SQSTM1/p62 were all indicative of MPL-induced autophagy. Consistent with this, we found inhibition of mTOR phosphorylation leading to suppression of the mTOR/p70S6K signalling pathway. Our findings provide the first evidence to show that MPL triggers autophagy through the deactivation of mTOR/p70S6K signalling pathway.     

MiR-497 decreases cisplatin resistance in ovarian cancer cells by targeting mTOR/P70S6K1

The mechanism of cisplatin resistance in ovarian cancer is not clearly understood. In the present investigation, we found that the expression levels of miR-497 were reduced in chemotherapy-resistant ovarian cancer cells and tumor tissues due to hypermethylation of miR-497 promoter. Low miR-497 expression levels were associated with chemo-resistant phonotype of ovarian cancer. By analyzing the expression levels of miR-497, mTOR and p70S6K1 in a clinical gene-expression array dataset, we found that mTOR and p70S6K1, two proteins correlated to chemotherapy-resistance in multiple types of human cancers, were inversely correlated with miR-497 levels in ovarian cancer tissues. By using an orthotopic ovarian tumor model and a Tet-On inducible miR-497 expression system, our results demonstrated that overexpression of miR-497 sensitizes the resistant ovarian tumor to cisplatin treatment. Therefore, we suggest that miR-497 might be used as a therapeutic supplement to increase ovarian cancer treatment response to cisplatin.     

哺乳动物雷帕霉素靶蛋白小分子干扰RNA对食管鳞癌细胞中mTOR-p70S6K信号通路及裸鼠移植瘤生长的影响

目的 检测哺乳动物雷帕霉素靶蛋白(mTOR)小分子干扰RNA(siRNA)对食管鳞癌中mTOR-p70S6K信号通路的阻断作用以及对裸鼠移植瘤生长的影响.方法 以食管鳞癌细胞株EC9706为研究对象,采用siRNA干扰、逆转录聚合酶链反应(RT-PCR)、Western blot、流式细胞术及CCK-8等方法,观察mTOR-p70S6K信号通路被阻断后,通路中各因子蛋白及mRNA表达的变化,及其对细胞增殖和凋亡的影响.进行裸鼠成瘤实验,观察mTOR siRNA对肿瘤生长的影响.结果 与未转染细胞相比,转染mTOR siRNA的细胞中mTOR和磷酸化p70S6K的表达水平降低(P<0.05),而pTOS6K的表达水平升高(P<0.05).转染mTOR siRNA后,细胞凋亡增加,细胞增殖能力降低,且对顺铂的敏感性增高,细胞被阻滞在G,期(P<0.05).mTOR siRNA能明显抑制裸鼠移植瘤的生长,siRNA组和siRNA+顺铂组的肿瘤抑制率分别为50.9%和62.3%.结论 mTOR siRNA能有效抑制mTOR-pTOS6K信号通路,抑制细胞增殖,促进细胞凋亡,在裸鼠体内能显著抑制肿瘤的生长.mTOR-pVOSSK信号通路在食管鳞癌发生发展中起重要作用.     

哺乳动物雷帕霉素靶蛋白小分子干扰RNA对食管鳞癌细胞中mTOR-p70S6K信号通路及裸鼠移植瘤生长的影响

目的 检测哺乳动物雷帕霉素靶蛋白(mTOR)小分子干扰RNA(siRNA)对食管鳞癌中mTOR-p70S6K信号通路的阻断作用以及对裸鼠移植瘤生长的影响.方法 以食管鳞癌细胞株EC9706为研究对象,采用siRNA干扰、逆转录聚合酶链反应(RT-PCR)、Western blot、流式细胞术及CCK-8等方法,观察mTOR-p70S6K信号通路被阻断后,通路中各因子蛋白及mRNA表达的变化,及其对细胞增殖和凋亡的影响.进行裸鼠成瘤实验,观察mTOR siRNA对肿瘤生长的影响.结果 与未转染细胞相比,转染mTOR siRNA的细胞中mTOR和磷酸化p70S6K的表达水平降低(P<0.05),而pTOS6K的表达水平升高(P<0.05).转染mTOR siRNA后,细胞凋亡增加,细胞增殖能力降低,且对顺铂的敏感性增高,细胞被阻滞在G,期(P<0.05).mTOR siRNA能明显抑制裸鼠移植瘤的生长,siRNA组和siRNA+顺铂组的肿瘤抑制率分别为50.9%和62.3%.结论 mTOR siRNA能有效抑制mTOR-pTOS6K信号通路,抑制细胞增殖,促进细胞凋亡,在裸鼠体内能显著抑制肿瘤的生长.mTOR-pVOSSK信号通路在食管鳞癌发生发展中起重要作用.     

哺乳动物雷帕霉素靶蛋白小分子干扰RNA对食管鳞癌细胞中mTOR-p70S6K信号通路及裸鼠移植瘤生长的影响

目的 检测哺乳动物雷帕霉素靶蛋白(mTOR)小分子干扰RNA(siRNA)对食管鳞癌中mTOR-p70S6K信号通路的阻断作用以及对裸鼠移植瘤生长的影响.方法 以食管鳞癌细胞株EC9706为研究对象,采用siRNA干扰、逆转录聚合酶链反应(RT-PCR)、Western blot、流式细胞术及CCK-8等方法,观察mTOR-p70S6K信号通路被阻断后,通路中各因子蛋白及mRNA表达的变化,及其对细胞增殖和凋亡的影响.进行裸鼠成瘤实验,观察mTOR siRNA对肿瘤生长的影响.结果 与未转染细胞相比,转染mTOR siRNA的细胞中mTOR和磷酸化p70S6K的表达水平降低(P<0.05),而pTOS6K的表达水平升高(P<0.05).转染mTOR siRNA后,细胞凋亡增加,细胞增殖能力降低,且对顺铂的敏感性增高,细胞被阻滞在G,期(P<0.05).mTOR siRNA能明显抑制裸鼠移植瘤的生长,siRNA组和siRNA+顺铂组的肿瘤抑制率分别为50.9%和62.3%.结论 mTOR siRNA能有效抑制mTOR-pTOS6K信号通路,抑制细胞增殖,促进细胞凋亡,在裸鼠体内能显著抑制肿瘤的生长.mTOR-pVOSSK信号通路在食管鳞癌发生发展中起重要作用.

Abstract：

Objective To investigate the effects of mTOR siRNA on mTOR-p70S6K signaling pathway in esophageal squamous cell carcinoma ( ESCC) cells in vitro, and growth and apoptosis in transplanted tumor in nude mice. Methods mTOR siRNA was transfected into ESCC cell line EC9706 cells. The expressions of factors of the mTOR/p70S6K signaling pathway were detected by RT-PCR and Western blot. DNA contents and cell apoptosis were determined by flow cytometry, and cell proliferation was measured by CCK-8 assay. The effects of mTOR siRNA on the transplanted tumor growth were assessed in nude mice. Results The levels of mTOR and p-p70S6K were significantly decreased ( P < 0.05 ) while the level of p70S6K was increased (P<0.05) in the cells transfected with mTOR siRNA, compared with that in untransfected cells and cells transfected with control siRNA. After being interfered by mTOR siRNA, the number of apoptotic cells was increased, cell proliferation became slower and cell cycle was arrested in G, phase compared with that in control cells. Also, mTOR siRNA inhibited the growth of transplanted tumor in vivo. Conclusions mTOR siRNA can effectively interfere in mTOR-p70S6K signaling pathway, induce cell apoptosis and inhibit cell proliferation and tumor growth, suggesting that mTOR-p70S6K signaling pathway plays an important role in the carcinogenesis and development of esophageal squamous cell carcinoma.     

PI3K/Akt/mTOR信号通路在上皮源性恶性肿瘤中的研究进展

磷脂酰肌醇3-激酶/蛋白激酶B/哺乳类动物雷帕霉素靶蛋白(PI3K/Akt/mTOR)信号通路不仅与细胞的增殖、存活及迁移密切相关,其与肿瘤的发生和发展也具有相关性.近年来,以该通路作为抗肿瘤治疗的靶点已成为研究的热点.本文就PI3K/Akt/mTOR信号通路在上皮来源恶性肿瘤活化、发生、发展中的作用,特别是皮肤鳞癌中的最新研究进展作一综述,并为皮肤肿瘤治疗及新药开发做一展望.     

Involvement of the TGF-beta and mTOR/p70S6Kinase pathways in the transformation process induced by v-ErbA

v-ErbA is the oncogenic form of TRα/c-ErbA which transforms chicken erythrocytic progenitors by blocking differentiation. The oncogenic property of v-ErbA has been correlated with its ability to antagonize ligand-dependent gene activation by TRα/c-ErbA and retinoic acid receptors. Nevertheless, its cytoplasmic retention suggests that v-ErbA could interfere with intracellular signaling pathways. We demonstrate that only the transforming form of v-ErbA confers to chicken erythroid progenitors a TGF-β independency and induces an activation of the mTOR/p70S6K pathway. In these cells, TGF-β and mTOR/p70S6K pathways regulate the expression of a known target gene of v-ErbA, band3. This is the first demonstration that v-ErbA is able to modulate specifically some signaling pathways leading to changes in the expression level of a gene involved in transformation.     

p70S6 kinase mediates breast cancer cell survival in response to surgical wound fluid stimulation

In early breast cancer, local relapses represent a determinant and not simply an indicator of risk for distant relapse and death. Notably, 90% of local recurrences occur at or close to the same quadrant of the primary cancer. Relevance of PI3K/mTOR/p70S6K signaling in breast tumorigenesis is very well documented. However, the pathway/s involved in the process of breast cancer local relapse are not well understood. The ribosomal protein p70S6K has been implicated in breast cancer cell response to post‐surgical inflammation, supporting the hypothesis that it may be crucial also for breast cancer recurrence. Here, we show that p70S6K activity is required for the survival of breast cancer cells challenged in “hostile” microenvironments. We found that impairment of p70S6K activity in breast cancer cells strongly decreased their tumor take rate in nude mice. In line with this observation, if cells were challenged to grow in anchorage independence or in clonogenic assay, growth of colonies was strongly dependent on an intact p70S6K signaling. This in vitro finding was particularly evident when breast cancer cells were grown in the presence of wound fluids harvested following surgery from breast cancer patients, suggesting that the stimuli present in the post‐surgical setting at least partially relied on activity of p70S6K to stimulate breast cancer relapse. From a mechanistic point of view, our results indicated that p70S6K signaling was able to activate Gli1 and up‐regulate the anti‐apoptotic protein Bcl2, thereby activating a survival response in breast cancer cells challenged in hostile settings. Our work highlights a previously poorly recognized function of p70S6K in preserving breast cancer cell survival, which could eventually be responsible for local relapse and opens the way to the design of new and more specific therapies aiming to restrain the deleterious effects of wound response.