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.     

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信号通路与大肠癌

哺乳动物雷帕霉素靶蛋白(mTOR)信号通路作为细胞内重要信号转导通路之一,通过影响下游多种效应分子的活化状态,调节细胞存活、增殖、转分化、迁移和细胞周期.mTOR这些调节机制的异常与大肠癌的发生和发展密切相关.目前mTOR抑制剂治疗大肠癌已处于临床试验中,并取得了一定的进展.     

哺乳动物雷帕霉素靶蛋白及其信号通路在胃癌中的研究进展

哺乳动物雷帕霉素靶蛋白(mTOR)及其信号通路控制着蛋白质合成、细胞的生长和代谢以及血管的生成等.其信号通路在胃癌中常被高度激活,与胃癌进展及预后密切相关.雷帕霉素及其衍生物可通过阻断mTOR通路的信号传递,抑制胃癌细胞生长,促进肿瘤坏死,并能与其他化疗药物产生协同作用,有望为胃癌预防和治疗提供有效的方法.     

哺乳动物雷帕霉素靶蛋白及其信号通路在胃癌中的研究进展

哺乳动物雷帕霉素靶蛋白(mTOR)及其信号通路控制着蛋白质合成、细胞的生长和代谢以及血管的生成等.其信号通路在胃癌中常被高度激活,与胃癌进展及预后密切相关.雷帕霉素及其衍生物可通过阻断mTOR通路的信号传递,抑制胃癌细胞生长,促进肿瘤坏死,并能与其他化疗药物产生协同作用,有望为胃癌预防和治疗提供有效的方法.     

siRNA沉默LKB1基因激活Hedgehog信号通路及对人乳腺癌裸鼠移植瘤模型生长的实验研究

目的探讨应用小分子干扰RNA(small interfering RNA,siRNA)沉默抑癌基因LKB1对人乳腺癌细胞MDA-MB-231中Hedgehog信号通路相关因子的表达及人乳腺癌裸鼠移植瘤模型的肿瘤生长的影响。方法构建LKB1基因siRNA质粒LKB1-siRNA;建立LKB1表达抑制的MDA-MB-435细胞模型;裸鼠乳晕皮下接种,建立人乳腺癌裸鼠移植瘤动物模型;成瘤后,观察肿瘤体积变化、裸鼠生存时间;并用Western印迹法检测瘤组织中LKB1和Hedgehog信号通路中信号肽Shh、Sufu、膜受体Ptch、Smo、转录因子Gli1、Hip蛋白表达的变化。结果 LKB1-siRNA质粒组裸鼠的肿瘤体积明显增长(P<0.05);肿瘤内LKB1基因表达水平明显下降,而Hedgehog信号通路相关因子Shh、Gli1、Ptch、Smo的表达升高,Hedgehog信号通路抑制因子Sufu、Hip表达下降。结论 LKB1基因siRNA能够明显抑制人乳腺癌裸鼠移植模型的LKB1基因的表达,上调Hedgehog信号通路相关因子的表达,促进肿瘤生长。LKB1基因和Hedgehog信号通路在乳腺癌细胞中呈现负相关表达。     

雷帕霉素对食管鳞癌细胞系EC9706的mTOR/p70S6K信号通路的影响

目的：观察雷帕霉素（rapamycin，rapa）对食管鳞癌细胞系EC9706的mTOR／p70S6K信号通路的影响。方法：采用免疫细胞化学证实mTOR／p70S6K信号通路的存在，然后通过DNALadder、RT—PCR、Westernblot及流式细胞术分别从DNA、RNA、蛋白及细胞水平研究rapa对细胞凋亡和信号通路的影响。结果：免疫细胞化学结果显示，在细胞核及细胞质中mTOR均呈阳性；rapa处理后有明显DNALadder产生，且mTOR的mRNA水平及蛋白水平下调。但是，mTOR下游的直接靶点p70S6K的mRNA水平及蛋白水平则升高，二者的变化程度均与rapa剂量的相关；流式细胞术检测结果表明，rapa可使细胞停滞于G1期。结论：食管鳞癌细胞系EC9706中存在mTOR／p70S6K信号通路并且处于激活状态，rapa能明显促进细胞凋亡并抑制该通路激活，从而间接抑制翻译的进行。     

RNA干扰PLCE1基因表达对食管鳞癌细胞周期和凋亡的影响

目的：通过siRNA干扰PLCE1基因表达,检测PLCE1对食管鳞癌细胞增殖周期和凋亡的影响,以探讨PLCE1的致癌机制。方法：采用免疫组织化学方法检测食管鳞癌组织和癌旁正常组织中PLCE1蛋白的表达水平;PLCE1特异性siRNA转染食管鳞癌细胞,荧光显微镜观察转染效率;半定量RT-PCR法检测转染后PLCE1沉默效果;流式细胞术检测干扰后细胞周期变化及凋亡情况。结果：PLCE1在食管鳞癌组织的表达高于正常组织（P=0.000）;siRNA转染后PLCE1表达明显减少（P=0.000）;与对照组相比,PLCE1干扰后可致G0/G1期细胞阻滞（P=0.001）,细胞凋亡增多（P=0.000）。结论：PLCE1在食管鳞癌组织中有较高表达;沉默PLCE1后可抑制癌细胞的增殖,促进其凋亡。     

增殖诱导配体小干扰RNA对人结直肠癌裸鼠移植瘤细胞增殖和凋亡的影响

目的 研究增殖诱导配体(APRIL)小干扰RNA(siRNA)对人结直肠癌裸鼠移植瘤细胞增殖和凋亡的抑制作用.方法 建立人结直肠癌裸鼠移植瘤模型,将裸鼠分为3组,瘤块内分别注射APRIL siRNA、空载体和PBS液,每2天注射1次,共2周.采用实时荧光定量PCR法和免疫组化SP法检测APRIL siRNA对APRILmRNA和蛋白表达的影响,采用酶联免疫吸附(ELISA)法检测肿瘤内增殖细胞核抗原(PCNA)含量的变化,采用免疫组化SP法检测肿瘤内bcl-2和bcl-xl蛋白的表达,采用原位末端标记(TUNEL)法检测肿瘤细胞的凋亡.结果 APRIL siRNA能敲低APRIL基因的表达水平,APRIL siRNA组移植瘤内APRIL mRNA的相对表达量为(0.13 ±0.05)×10-3,明显低于空载体组[(0.95 ±0.04)× 10-3]和空白对照组[(0.96±0.05)×10-3,P＜0.05].APRIL siRNA组APRIL蛋白的表达比空载体组和空白对照组降低了(87.5%±5.0%,P＜0.05).APRILsiRNA组裸鼠移植瘤生长缓慢,瘤块重量较空载体组和PBS对照组明显降低(P＜0.05).APRIL siRNA组移植瘤内PCNA的含量为(176.8±18.1)ng/ml,明显低于空载体组[(330.0±20.5)ng/ml]和空白对照组[(328.4±22.8)ng/ml,P＜0.05];bcl-2和bcl-xl蛋白的表达量也较空载体组和空白对照组明显降低(P＜0.05).APRIL siRNA组移植瘤内凋亡细胞的数量增多,凋亡率为40.1%±2.5%,明显高于空载体组(2.5%±0.1%)和空白对照组(2.5%±0.2%,P＜0.05).结论 APRIL siRNA能在裸鼠体内抑制人结直肠癌细胞的增殖,并促进细胞凋亡,达到显著的抑瘤效果.APRIL基因可能成为人结直肠癌基因靶向沉默治疗的重要候选基因之一.     

赖氨酰氧化酶表达干扰对乳腺癌裸鼠移植瘤生长影响及机制研究

目的:探讨抑制乳腺癌细胞MD-MB-231中赖氨酰氧化酶(lysyl oxidase,LOX)的表达对乳腺癌裸鼠移植瘤生长的影响及可能机制。方法:设计合成特异性LOX基因慢病毒干扰载体(LOX-RNAi-LV)转染乳腺癌细胞MDA-MB-231,采用荧光定量PCR和蛋白质印迹法检测LOX mRNA和蛋白的表达;建立乳腺癌裸鼠原位移植模型,观察移植瘤的生长情况。采用免疫组化方法检测移植瘤组织中LOX蛋白及肿瘤增殖、转移相关蛋白Ki-67、MMP-2、MMP-9和HIF-1α的表达。结果:转染LOX-RNAi-LV的人乳腺癌细胞MDA-MB-231中LOX mRNA和蛋白的相对表达量分别为0.102±0.083和0.156±0.004,与空白对照组(0.945±0.158和0.916±0.007)相比,表达率均明显下调,抑制率分别为89.2%和83.0%。裸鼠原位接种癌细胞后6d均有肿瘤生成,40d后接种转染LOX-RNAi-LV的MDA-MB-231细胞的裸鼠移植瘤体积为(108.89±26.61)mm3,质量为(0.117±0.021)g;均明显低于空白对照组(400.15±79.81)mm3,(0.433±0.068)g,以及阴性对照组(380.15±65.81)mm3,(0.404±0.053)g,差异有统计学意义,P值均为0.000。移植瘤组织中LOX、Ki-67、MMP-2、MMP-9和HIF-1α蛋白相对表达水平分别为0.198±0.036、0.347±0.054、0.379±0.048、0.335±0.067和0.307±0.073,较空白对照组和阴性对照组明显降低,P值均<0.01。结论:干扰MDA-MB-231中LOX的表达,可抑制乳腺癌裸鼠移植瘤的生长侵袭,LOX可能通过调节Ki-67、MMP-2、MMP-9和HIF-1α蛋白的表达,在乳腺癌的侵袭转移中发挥作用。     

雷帕霉素对食管鳞癌裸鼠移植瘤生长及mTOR/p70S6K信号通路的影响

目的:探讨雷帕霉素(rapamycin, RAPA)对荷人食管鳞癌裸鼠移植瘤生长及mTOR/p70S6K信号通路的影响.方法:建立人食管鳞癌细胞株EC9706的裸鼠移植瘤模型,观察经RAPA和RAPA联合顺铂治疗后荷瘤裸鼠的肿瘤生长情况;应用TUNEL、RT-PCR及Western 印迹法观察肿瘤组织中的细胞凋亡、mTOR和p70S6K mRNA以及mTOR、p70S6K和p-p70S6K的蛋白表达.结果:RAPA和顺铂均使肿瘤生长速度减慢(P<0.05),并且2者联合应用效果更好(P<0.01);TUNEL检测发现,RAPA在体内能引起EC9706细胞的凋亡(P<0.05);RT-PCR和Western 印迹法检测结果表明,RAPA在体内降低了mTOR、p70S6K mRNA和mTOR、p-p70S6K的蛋白表达,但可提高p70S6K的蛋白表达水平.结论:RAPA在体内通过抑制mTOR/p70S6K信号通路的活性促进细胞凋亡,从而抑制人食管鳞癌细胞EC9706裸鼠移植瘤的生长.     

干扰mTOR表达增强食管鳞癌EC9706细胞对雷帕霉素的敏感性

目的：观察哺乳动物雷帕霉素靶蛋白（mammalian target of rapamycin,mTOR)特异性小干扰RNA（mTOR-siRNA）干扰mTOR表达后,食管鳞癌EC9706细胞对雷帕霉素(rapamycin)敏感性的变化。方法：mTOR-siRNA转染EC9706细胞, RT-PCR检测干扰效果。mTOR-siRNA转染前后的EC9706细胞用雷帕霉素处理,Western blotting检测EC9706细胞中mTOR及其下游p70S6K蛋白的表达;流式细胞术检测EC9706细胞的周期及凋亡,CCK-8试剂盒检测EC9706细胞的增殖。结果：mTOR-siRNA下调EC9706细胞中mTOR mRNA的表达（P<0.05或P<0.01);雷帕霉素抑制EC9706细胞中mTOR和p-p70S6K蛋白的表达（P<0.05),并促进p70S6K蛋白表达(P<0.01),且mTOR-siRNA转染后此作用更明显（P<0.05）。雷帕霉素可诱导EC9706细胞凋亡(P<0.01)、抑制EC9706细胞增殖(P<0.05或P<0.01)、使EC9706细胞阻滞于G1期(P<0.01),且mTOR-siRNA转染后这些作用更强（P<0.05）。结论：mTOR-siRNA能特异性下调食管鳞癌EC9706细胞中mTOR表达,提高EC9706细胞对雷帕霉素的敏感性。     

An activated mTOR/p70S6K signaling pathway in esophageal squamous cell carcinoma cell lines and inhibition of the pathway by rapamycin and siRNA against mTOR

mTOR/p70S6K pathway is considered a central regulator in various malignant tumors, but its roles in esophageal squamous cell carcinoma (ESCC), which is a common cause of mortality in China, remain unknown. Here, we identify that the mTOR/p70S6K pathway is activated in ESCC; rapamycin and siRNA against mTOR rapidly inhibited expression of mTOR and the phosphorylation of its major downstream effectors, p70S6K and 4E-BP1, arrested cells in the G(0)/G(1) phase and induced apoptosis of ESCC cells. The findings may lay a foundation for making further investigations on the mTOR/p70S6K pathway as a potential target for ESCC therapy.     

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.     

AKt／mTOR 信号通路中 p70S6K1、4E －BPs 在促进肿瘤发生作用中的研究进展

当受细胞外生长因子等刺激作用后,可激活 PI3K／AKt／mTOR 信号通路,参与控制细胞的生长、增殖、生存、凋亡。AKt／mTOR 信号通路在肿瘤的发生发展过程中起着很重要的促进作用。AKt／mTOR 信号通路在肿瘤细胞中能够通过 p70S6K1和4E －BPs 的作用抑制细胞的凋亡,促进核糖体以及蛋白质的合成、促进肿瘤细胞的侵袭和转移、促进细胞周期进展、促进肿瘤血管的生成,进而促进肿瘤的发生发展。本文就AKt／mTOR 信号通路通过 p70S6K1和4E －BPs 促进肿瘤发生的机制进行综述。     

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.