mTOR信号通路与消化系统肿瘤

哺乳动物雷帕霉素靶蛋白(mTOR)信号途径的异常与肿瘤密切相关.经典和新型的mTOR抑制剂在消化系统肿瘤的临床前和临床研究显示了该类药物具有抗肿瘤作用,并且能够增强肿瘤细胞对现有化疗药物的敏感性.     

mTOR siRNA对喉鳞状细胞癌Hep-2细胞生物学行为的影响

目的观察mTOR siRNA对喉鳞状细胞癌Hep-2细胞增殖能力的影响。方法选取45例喉鳞状细胞癌组织和45例正常喉黏膜组织,采用免疫组织化学法检测mTOR蛋白的表达;将喉鳞状细胞癌Hep-2细胞分为空白对照组、空载体组和mTOR siRNA组,及正常对照组、溶剂对照组和雷帕霉素组,分别利用mTOR siRNA和雷帕霉素进行治疗,采用Western bloting法检测不同浓度的mTOR siRNA和雷帕霉素分别处理细胞后对mTOR蛋白表达的影响,并采用CCK-8试剂盒分析mTOR蛋白表达下调对喉鳞状细胞癌Hep-2细胞增殖能力的影响。结果 mTOR蛋白在喉鳞状细胞癌组织中表达的阳性率显著高于正常喉黏膜组织(P<0.05)。3种不同浓度mTOR siRNA分别转染Hep-2细胞24、48、72 h,各组与空白对照组、空载体组相比,mTOR蛋白表达均有所降低(P<0.05),且mTOR蛋白表达随mTOR siRNA浓度的增加、作用时间的延长而降低(P<0.05)。3种不同浓度雷帕霉素处理Hep-2细胞24、48、72 h,各组与溶剂对照组及正常对照组相比,mTOR蛋白表达量均有所降低(P<0.05);且mTOR蛋白表达随雷帕霉素浓度的增加、处理时间的延长而降低(P<0.05)。与空白对照组、空载体组相比,各mTOR siRNA组的Hep-2细胞增殖在转染后24、48、72 h均受到明显抑制(P<0.05)。结论 mTOR siRNA均能降低喉鳞状细胞癌Hep-2细胞中mTOR蛋白的表达,有效抑制细胞的生长,为喉鳞状细胞癌的分子治疗提供了理论依据。     

微波辐射对人成神经母细胞瘤SH-SY5Y细胞增殖与分化的影响

目的观察微波辐射对人成神经母细胞瘤SH-SY5Y细胞增殖与分化的影响。 方法  采用10、30、50 mW/cm²辐射强度的微波辐射SH-SY5Y细胞5 min,0 mW/cm²为对照组,锥虫蓝拒染法进行细胞计数并计算增殖率;20 μmol/L全反式维甲酸黑暗下诱导分化72 h后,在光学显微镜下观察细胞分化的形态并计算分化细胞率;流式细胞仪检测细胞周期;蛋白质印迹检测细胞神经纤丝重链亚基的蛋白表达。结果微波辐射后随辐射强度增加,细胞增殖率在各时间点上均出现不同程度的梯度抑制,与对照组（0 mW/cm²）相比,10 mW/cm²辐射组在72 h时出现明显抑制;30 mW/cm²辐射组在48 h时出现明显抑制;50 mW/cm2辐射组在辐射12 h时就出现明显抑制;20 μmol/L全反式维甲酸黑暗下诱导分化72 h后,30、50 mW/cm²微波辐射组细胞分化的数量少于对照组细胞,而且细胞轴突长度短于对照组细胞;随着辐射强度的增加,G₀/G₁期的SH-SY5Y细胞比例逐渐增加,S 期细胞比例逐渐减少,G₂+M 期细胞比例变化相对较小;微波辐射后,SH-SY5Y细胞总NF-H蛋白表达无明显变化,但磷酸化的NF-H蛋白表达随辐射强度的增加逐渐降低。结论微波辐射可同时抑制SH-SY5Y细胞增殖与分化并呈现明显的剂量依赖性抑制作用;细胞周期呈G₀/G₁期阻滞;对NF-H的表达无影响,但明显抑制了NF-H的磷酸化。     

丙戊酸促进神经母细胞瘤细胞自噬性死亡

目的探讨丙戊酸(VPA)对神经母细胞瘤细胞自噬性死亡的调控。方法用含不同浓度的VPA培养基培养SH-SY5Y细胞,应用MTT法检测细胞的存活率,乳酸脱氢酶(LDH)检测细胞损伤,单丹磺酰尸胺(MDC)染色评价细胞质内酸性自噬泡的形成,Western blotting法检测巨自噬相关蛋白LC3-Ⅱ/LC3-Ⅰ的比值及Beclin-1的表达。结果与对照组比较,VPA孵育48 h后,SH-SY5Y细胞存活率明显降低,且具有剂量依赖性(P<0.05);SH-SY5Y细胞培养基中LDH明显增高,且具有剂量依赖性(P<0.05);VPA诱导细胞内LC3-Ⅱ/LC3-Ⅰ的比值及Beclin-1的表达水平明显上调(P<0.05)。结论 VPA诱导神经母细胞瘤细胞细胞自噬性死亡,为神经母细胞瘤的治疗提供新的手段。     

食管鳞癌EC-9706细胞中mTOR信号通路在TGF-β1介导的EMT中的作用

目的:探讨食管鳞癌EC-9706细胞中哺乳动物雷帕霉素靶蛋白(mammalian target of rapamycin,mTOR)信号通路活化在转化生长因子β1(transforming growth factor beta 1,TGF-β1)介导的上皮-间质转化(epithelial-mesenchymal transition,EMT)中的作用.方法:TGF-β1(终质量浓度为7.5 ng/mL)或TGF-β1(终质量浓度为7.5 ng/mL)+雷帕霉素(终浓度为200 nmol/L)作用食管鳞癌EC-9706细胞后,在倒置显微镜下观察细胞形态的变化,RT-PCR及蛋白质印迹法检测EC-9706细胞中mTOR和E-cadherin mRNA及其蛋白的表达,通过Boyden小室实验检测EC-9706细胞侵袭能力的变化.构建裸鼠食管鳞癌EC-9706细胞移植瘤模型,RT-PCR及蛋白质免疫印迹法检测雷帕霉素作用后,移植瘤组织中mTOR和E-cadherin mRNA及其蛋白的表达.结果:TGF-β1作用后,EC-9706细胞梭形化明显,mTOR mRNA及p-mTOR蛋白的表达水平高于未进行任何处理的EC-9706细胞对照组(P＜0.05),E-cadherin mRNA及其蛋白的表达水平低于对照组(P＜0.05),细胞侵袭能力明显高于对照组(P＜0.05); TGF-β1+雷帕霉素组EC-9706细胞mTOR mRNA及p-mTOR蛋白的表达水平低于TGF-β1单药作用组(P＜0.05),E-cadherin mRNA及其蛋白的表达水平高于TGF-β1单药作用组(P＜0.05),细胞侵袭能力较TGF-β1单药作用组明显下降(P＜0.05).雷帕霉素作用后,裸鼠食管鳞癌EC-9706细胞移植瘤组织中mTOR mRNA及p-mTOR蛋白的表达水平低于对照组(P＜0.05),E-cadherin mRNA及其蛋白的表达水平高于对照组(P＜0.05).结论:食管鳞癌EC-9706细胞中mTOR可能参与TGF-β1介导的EMT的发生,mTOR可能作为食管鳞癌基因治疗中的有效靶点发挥作用.     

PBDE-47对人神经母细胞瘤SH-SY5Y细胞致突变作用

背景与目的:探讨2,2',4,4'-四溴联苯醚(2,2',4,4'-tetrabromodiphenyl ethers,PBDE-47)对人神经母细胞瘤SH-SY5Y细胞的致突变作用.材料与方法:设空白对照组、溶剂对照组、3个不同BDE-47剂量的试验组(1 μg、2 μg、4 μg/ml)和阳性对照组(MMC),共6组.SH-SY5Y细胞分别暴露于各组不同受试物24 h后,采用胞质分裂阻断法测定微核率、核浆桥率. 结果:PBDE-47可诱导SH-SY5Y细胞核分裂指数呈剂量依赖性下降,微核细胞率和核浆桥率呈剂量依赖性增加;2 μg/ml和4 μg/ml的染毒剂量可引起SH-SY5Y细胞核分裂指数明显降低(P＜0.05)以及微核细胞率和核浆桥率的明显增加(P＜0.05),而仅在4 μg/ml PBDE-47染毒组发现微核率明显增加(P＜0.05).结论:PBDE-47可诱导SH-SY5Y细胞微核和核浆桥的形成,具有致突变作用.     

应用Alamar blue法检测TRAIL对神经母细胞瘤细胞的细胞毒作用

目的:神经母细胞瘤(neuroblastoma,NB)细胞对TRAIL的杀伤效应不敏感与其Caspase 8表达的缺失有关.本研究中我们用γ-干扰素(Interferon γ,IFNγ)诱导NB细胞株CHP212和SH-SY5Y(SY5Y)Caspase 8表达,观察表达Caspase 8的NB细胞是否对TRAIL的细胞毒作用敏感,从而探讨Alamar blue法用于测定细胞体外增殖及细胞毒实验的可行性.方法:应用Western-blot方法检测IFNγ作用前后NB细胞Caspase 8蛋白的表达;应用Alamar blue还原率测定IFNγ、TRAIL、IFNγ+TRAIL、Caspase 8抑制剂+TRAIL对NB细胞生长的影响.结果:对TRAIL敏感的CHP212细胞表达Caspase 8且经IFNγ处理后Caspase 8表达水平逐步增加;对TRAIL不敏感的SY5Y细胞不表达Caspase 8,IFNγ作用后其Caspase 8蛋白表达明显增加.CHP212细胞还原率随TRAIL浓度的增加和作用时间的延长而降低,各实验组与对照组比较有显著差别(P<0.05).SY5Y对TRAIL耐药,而IFNγ+TRAIL组的SY5Y细胞还原率与单独用IFNγ或TRAIL组比较,显著降低(P<0.01).结论:Alamar blue还原率测定结果表明CHP212细胞对TRAIL的细胞毒作用敏感,存在时间和剂量依赖性;经IFNγ诱导表达Caspase 8的SYSY细胞对TRAIL的细胞毒作用亦敏感.本研究结果证实Alamar blue法是一种简便、敏感、安全的方法,可用于体外测定细胞增殖及化疗药的细胞毒作用.     

姜黄素下调mTOR诱导人肺癌A549细胞自噬的研究

[目的]研究姜黄素诱导人肺癌A549细胞自噬现象及与哺乳动物雷帕霉素靶蛋白（mTOR）的关系。[方法]采用CCK-8法检测姜黄素对A549细胞增殖的抑制作用;采用吖啶橙染色（AO）及转染GFP-LC3质粒荧光显微镜下观察姜黄素处理后A549细胞的自噬现象;采用Western blot法检测微管相关蛋白轻链Ⅱ（LC3Ⅱ）、微管相关蛋白轻链Ⅰ（LC3Ⅰ）、mTOR表达的变化。[结果]姜黄素对人肺癌A549细胞增殖有明显抑制作用,且成明显的剂量—时间依赖关系。AO染色结果显示,与对照组相比,姜黄素40μmol/L组及Rapa组细胞内酸性滤泡染成亮红色荧光比例增多;与姜黄素40μmol/L组相比,姜黄素40μmol/L＋自噬抑制剂3-甲基腺嘌呤（3-MA）组及3-MA组亮红色荧光比例下降。细胞转染GFP-LC3后姜黄素40μmol/L组和Rapa组胞浆内点状的绿色荧光斑点明显;与姜黄素40μmol/L组相比,姜黄素40μmol/L＋3-MA组及3-MA组胞浆内点状的绿色荧光斑点明显比例有所下降。Western blot法检测结果显示,与对照组相比,姜黄素40μmol/L组作用24h后,LC3-Ⅱ/LC3-Ⅰ表达显著升高（P〈0.05）,姜黄素40μmol/L＋3-MA组LC3Ⅱ/LC3-Ⅰ表达低于姜黄素40μmol/L组（P〈0.05）。姜黄素40μmol/L组mTOR表达显著下降（P〈0.01）,姜黄素40μmol/L＋3-MA组mTOR表达高于姜黄素40μmol/L组（P〈0.05）。[结论]姜黄素能够明显抑制A549细胞增殖并诱导A549细胞发生自噬,同时还能够明显抑制mTOR蛋白的表达水平,其机理可能与mTOR的信号通路有关。     

维拉帕米与长春新碱联合应用对神经母细胞瘤细胞的作用

探讨维拉帕米能否提高神经母细胞瘤细胞对长春新碱的敏感性。方法对２３例神经母细胞瘤组织进行分离获得肿瘤细胞,采用原代细胞培养及ＭＴＴ检测药敏的方法,测定了长春新碱及其与维拉帕米合用时对肿瘤细胞的抑制率。结论化疗对长春新碱敏感性降低的神经母细胞瘤患者,化疗时加用维拉帕米可望提高化疗结果。     

应用Alamarblue法检测TRAIL对神经母细胞瘤细胞的细胞毒作用

目的：神经母细胞瘤（neuroblastoma,NB）细胞对TRAIL的杀伤效应不敏感与其Caspase 8表达的缺失有关。本研究中我们用γ-干扰素（Interferonγ,IFNγ）诱导NB细胞株CHP212和SH-SY5Y（SY5Y）Caspase 8表达,观察表达Caspase 8的NB细胞是否对TRAIL的细胞毒作用敏感,从而探讨Alamar blue法用于测定细胞体外增殖及细胞毒实验的可行性。方法：应用Western-blot方法检测IFNγ作用前后NB细胞Caspase 8蛋白的表达;应用Alamar blue还原率测定IFNγ、TRAIL、IFNγ＋TRAIL、Caspase 8抑制剂＋TRAIL对NB细胞生长的影响。结果：对TRAIL敏感的CHP212细胞表达Caspase 8且经IFNγ处理后Caspase 8表达水平逐步增加;对TRAIL不敏感的SY5Y细胞不表达Caspase 8,IFNγ作用后其Caspase 8蛋白表达明显增加。CHP212细胞还原率随TRAIL浓度的增加和作用时间的延长而降低,各实验组与对照组比较有显著差别（P〈0.05）。SY5Y对TRAIL耐药,而IFNγ＋TRAIL组的SY5Y细胞还原率与单独用IFNγ或TRAIL组比较,显著降低（P〈0.01）。结论：Alamar blue还原率测定结果表明CHP212细胞对TRAIL的细胞毒作用敏感,存在时间和剂量依赖性;经IFNγ诱导表达Caspase 8的SY5Y细胞对TRAIL的细胞毒作用亦敏感。本研究结果证实Alamar blue法是一种简便、敏感、安全的方法,可用于体外测定细胞增殖及化疗药的细胞毒作用。     

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.     

柴胡皂苷d通过AKT/mTOR信号通路调控胶质瘤C6细胞自噬

目的 探讨柴胡皂苷d在胶质瘤C6细胞自噬中的作用及其机制。方法 分别以终浓度为0 μmol/L（Control组）、2 μmol/L、4 μmol/L、6 μmol/L、8 μmol/L、10 μmol/L、12 μmol/L的柴胡皂苷d作用胶质瘤C6细胞后,用CCK⁃8检测细胞增殖能力,后续分别采用克隆形成实验、划痕实验检测柴胡皂苷d（8 μmol/L）对胶质瘤C6细胞增殖能力和细胞迁移能力的影响,Western blot和qRT⁃PCR检测胶质瘤C6细胞中自噬相关蛋白Beclin1、LC3和AKT/mTOR信号通路相关蛋白及基因的表达情况。结果 与Control组比较,各浓度柴胡皂苷d均能抑制胶质瘤C6细胞增殖且增殖抑制率随着药物浓度的升高而升高（均P<0.01）。8 μmol/L柴胡皂苷d作用24 h后,与Control组比较,胶质瘤C6细胞的克隆形成数目显著减少［（479.33±30.66）个 vs （258.66±73.35）个,P<0.01］,细胞迁移率显著降低［（70.83±4.29）% vs （19.47±1.71）%,P<0.001］,自噬相关蛋白Beclin1和LC3的蛋白及mRNA表达水平均显著升高（均P<0.01）,而AKT和mTOR信号蛋白及mRNA表达水平均降低（均P<0.01）。结论 柴胡皂苷d可能通过抑制AKT/mTOR信号通路诱导胶质瘤C6细胞发生自噬并抑制其增殖与迁移。     

Matrine exerts antitumor activity in cervical cancer by protective autophagy via the Akt/mTOR pathway in vitro and in vivo

Matrine is a quinazoline alkaloid extracted from Sophora flavescens. The aim of the present study was to determine whether matrine can induce autophagy in the human HeLa and SiHa cervical cancer cell lines in vitro and in vivo. Cell viability assay was used to assess the suppressive effect of matrine and cisplatin on the proliferation of HeLa and SiHa cells. A total of 28 4-week-old female BALB/c nude mice were used for the in vivo study. Autophagy and protein expression were observed via transmission electron microscopy, monodansylcadaverine and immunohistochemical staining and western blotting. The inhibitory effect of matrine on the proliferation of cervical cancer cells was time- and dose-dependent. The combination of matrine and cisplatin synergistically inhibited the proliferation of cervical cancer cells in vitro and in vivo. Transmission electron microscopy showed that after the addition of matrine, numerous autophagosomes and autophagolysosomes were observable in HeLa and SiHa cells, as demonstrated by monodansylcadaverine staining. Western blotting and immunohistochemical staining showed that as the concentration of matrine increased, the expression of the autophagy marker LC3A/B-II also increased significantly in vitro and in vivo. These findings suggested that matrine inhibited the proliferation of cervical cancer cells and induced autophagy by inhibiting the Akt/mTOR signaling pathway. Thus, matrine may represented a potential candidate in combination therapy for cervical cancer as an inducer of autophagy.     

Oleuropein aglycone induces autophagy via the AMPK/mTOR signalling pathway: a mechanistic insight

The healthy effects of plant polyphenols, some of which characterize the so-called Mediterranean diet, have been shown to arise from epigenetic and biological modifications resulting, among others, in autophagy stimulation. Our previous work highlighted the beneficial effects of oleuropein aglycone (OLE), the main polyphenol found in the extra virgin olive oil, against neurodegeneration both in cultured cells and in model organisms, focusing, in particular, autophagy activation. In this study we investigated more in depth the molecular and cellular mechanisms of autophagy induction by OLE using cultured neuroblastoma cells and an OLE-fed mouse model of amylod beta (Aβ) deposition. We found that OLE triggers autophagy in cultured cells through the Ca²⁺-CAMKKβ–AMPK axis. In particular, in these cells OLE induces a rapid release of Ca²⁺ from the SR stores which, in turn, activates CAMKKβ, with subsequent phosphorylation and activation of AMPK. The link between AMPK activation and mTOR inhibition was shown in the OLE-fed animal model in which we found that decreased phospho-mTOR immunoreactivity and phosphorylated mTOR substrate p70 S6K levels match enhanced phospho-AMPK levels, supporting the idea that autophagy activation by OLE proceeds through mTOR inhibition. Our results agree with those reported for other plant polyphenols, suggesting a shared molecular mechanism underlying the healthy effects of these substances against ageing, neurodegeneration, cancer, diabetes and other diseases implying autophagy dysfunction.     

PI3K/AKT/mTOR pathway inhibitors inhibit the growth of melanoma cells with mTOR H2189Y mutations in vitro

mTOR is an important therapeutic target in many types of cancers. In melanoma, the mTOR nonsynonymous mutation rate is up to 10.4%. However, mTOR inhibitors have shown limited effects in clinical trials of melanoma. Because mTOR mutations are distributed, not selecting patients with specific mTOR mutations may be the main reason for therapeutic failures. Our previous research found that mutations in the mTOR P2213S and S2215Y kinase domains resulted in gain-of-function and were sensitive to specific inhibitors. The purpose of this study was to test the effect of heterozygous/homozygous H2189Y mutations on downstream pathways and sensitivity to inhibitors. mTOR kinase activity was analyzed by western blot and a K-LISA? mTOR activity kit. The sensitivity of melanoma cells to inhibitors was tested by a proliferation assay. The expression of downstream pathway proteins was also analyzed by western blot. The results showed that heterozygous/homozygous H2189Y mutations were gain-of-function. The heterozygous H2189Y mutation was sensitive to the AKT inhibitor, AZD5363, and the phosphoinositide 3-kinase inhibitor, LY294002. The homozygous H2189Y mutation was sensitive to the mTOR inhibitor, everolimus, and the AKT inhibitors AZD5363 and MK-2206 2HCL,and the phosphoinositide 3-kinase inhibitor, LY294002. These results indicated that homozygous mutations in the kinase domain have a greater effect on protein function than heterozygous mutations. The mTOR kinase domain may play an important role in mTOR kinase activity and may be the target of selective inhibitors. Our study can facilitate the selection of appropriate inhibitors for patients in clinical trials.     

异莲心碱通过PI3K/Akt/mTOR信号通路影响结肠癌SW480细胞增殖、 凋亡和自噬

目的：探讨异莲心碱（Iso）通过PI3K/Akt/mTOR信号通路对结肠癌SW480细胞增殖、凋亡和自噬的影响。方法：用 10、20和40 μmol/L的Iso处理结肠癌SW480细胞,CCK-8法、流式细胞术和WB法分别检测Iso对细胞增殖活力、凋亡和自噬相关 蛋白LC3Ⅰ、LC3Ⅱ、p62表达的影响。然后,用20 μmol/L的Iso和25 μmol/L的PI3K激活剂740 Y-P分别处理SW480细胞,将细 胞分为对照组、740 Y-P组、Iso组和Iso+740 Y-P组,流式细胞术、WB法检测Iso和740 Y-P对各组细胞凋亡及细胞中LC3Ⅰ、LC3Ⅱ、 p62、PI3K、p-PI3K、 mTOR和p-mTOR蛋白表达的影响。结果：10、20和40 μmol/L的Iso处理后,SW480细胞增殖活力均显著下 降（均P<0.05）,细胞凋亡率均显著升高（均P<0.05）,LC3Ⅱ/LC3Ⅰ表达均显著上调（均P<0.05）,p26蛋白表达显著下调（P<0.05）。 Iso和740 Y-P处理后,与对照组相比,740 Y-P 组细胞凋亡率、LC3Ⅱ/LC3Ⅰ表达均显著下降（均P<0.05）,p26、p-PI3K/PI3K和 p-mTOR/mTOR 表达均显著升高（均 P<0.05）;Iso 组 细胞凋亡率、LC3Ⅱ/LC3Ⅰ表达升高（均 P<0.05）,p26、p-PI3K/PI3K和 p-mTOR/mTOR 表达均显著下降（均 P<0.05）;与 740 Y-P 组相比,Iso+740 Y-P 组细胞凋亡率、LC3Ⅱ/LC3Ⅰ表达升高（P<0.05）, p26、p-PI3K/PI3K和p-mTOR/mTOR表达均显著下降（均P<0.05）;与Iso组相比,Iso+740 Y-P组细胞凋亡率、LC3Ⅱ/LC3Ⅰ表达下 降（均P<0.05）,p26、p-PI3K/PI3K和p-mTOR/mTOR表达均显著升高（均P<0.05）。结论：Iso通过抑制PI3K/Akt/mTOR信号通路 抑制结肠癌SW480细胞增殖并诱导细胞凋亡和自噬。     

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.     

mTOR信号通路与滑膜肉瘤研究进展

哺乳动物雷帕霉素靶蛋白(Mammalian target of rapamycin,mTOR)是一种丝/苏氨酸蛋白激酶,属于磷脂酰肌醇三激酶-相关激酶家族,通过影响Akt、4EBP1和S6K1等关键因子在肿瘤的发生发展中扮演重要角色.滑膜肉瘤(Synovial sarcoma,SS)是一种恶性程度极高的软组织肉瘤,早期外科手术及化疗是目前主流的治疗方式,但晚期生存率仍不理想,通过对信号通路转导的研究为滑膜肉瘤的治疗提供了新的研究方向.本文对近年来mTOR与滑膜肉瘤的相关研究进行综述.     

Effects of 2-dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione on autophagy and the PI3K/AKT/mTOR signaling pathway in human cholangiocarcinoma QBC939 cells

Background2-dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione (DMDD) has been reported to have good antitumor effects. The aim of this study was to investigate whether DMDD induces apoptosis and autophagy in human cholangiocarcinoma (CCA) QBC939 cells and determine its effect on the PI3K/AKT/mTOR signaling pathway.MethodsQBC939 cells were cultured in vitro and changes in cell viability were detected by the Cell Counting Kit (CCK8) assay after treatment with different concentrations of DMDD for 24, 48, and 72 h. The cells were divided into control and DMDD-treated groups (treated concentrations were 10, 15, and 20 µM/L), and the cell cycle, apoptosis, and autophagic vesicles were assessed. The expression levels of PI3K, AKT, mTOR, microtubule-associated protein 1 light chain 3 beta (LC3-II)/I, Beclin-1, and P62 were detected by Western blot. A xenograft mouse model was constructed to detect the effect of DMDD on CCA.ResultsThe experimental results showed that DMDD was able to inhibit proliferation, migration, and invasion and induce cell cycle arrest and autophagy of QBC939 cells. In addition, DMDD decreased the protein expression of PI3K, AKT, and mTOR and increased the expression of LC3-II/I, Beclin-1, and P62. In mice, DMDD was able to inhibit the growth of tumors.ConclusionsDMDD inhibits CCA cell viability and induces cell cycle arrest and autophagy by a mechanism that may be related to the downregulation of the PI3K/AKT/mTOR signaling pathway.