PI3K/Akt/mTOR信号传导通路与成人T淋巴细胞白血病关系的研究进展

成人T淋巴细胞白血病(ATL)是严重危害人类健康的一种疾病,它是由与H IV类似的逆转录病毒HTLV-I感染CD4+T细胞而诱发的恶性肿瘤。HTLV-Ⅰ导致ATL中起主要作用的是Tax蛋白,其反式激活作用占有重要地位,它可以激活PI3K/AKT/mTOR信号途径。PI3K/Akt/mTOR被认为是蛋白质合成的主要信号调节通路,研究表明该信号传导通路是与细胞增殖和细胞凋亡关系最密切的信号传导通路之一,其在成人T淋巴细胞白血病的发生、发展治疗及转归中发挥重要作用,并且已经成为治疗的新靶点。本文就PI3K/Akt/mTOR信号传导通路以及与ATL关系的研究进展作如下综述。     

基于PI3K/AKT/mTOR通路的三百棒促进脂多糖诱导的RAW 264.7细胞自噬并抑制炎症CSCD

三百棒来源于芸香科植物飞龙掌血Toddalia asiatica(L.)Lam的根,是一种天然土家族中草药,具有抗炎、抗风湿、抗肿瘤、抗微生物等药理活性。其毒副作用小,疗效显著的特点使之成为当前研究热点。许多天然产物已被证明可通过靶向PI3K/AKT/mTOR介导的自噬来抑制炎症及自身免疫性疾病,本项研究通过调节PI3K/AKT/mTOR信号通路来研究三百棒醇提物(Toddalia asiatica alcohol extract,TAAE)对自噬的影响,用脂多糖(LPS)诱导单核巨噬细胞(RAW 264.7)建立炎症模型,通过细胞毒性检测试剂盒检测TAAE对细胞活力的影响,并筛选出药物的浓度及干预时间,透射电镜和单丹磺酰尸胺染色检测巨噬细胞的生物学功能,酶联免疫吸附法检测上清液中相关炎症因子水平,Western blot检测自噬和通路相关蛋白的表达水平;并采用自噬早期抑制剂(3-MA)和通路PI3K激动剂(740Y-P)进一步验证自噬对炎症和信号通路的影响。实验结果表明TAAE可能通过抑制PI3K/AKT/mTOR信号通路,促进自噬泡的形成、自噬体溶酶体融合和降解,降低LPS处理的RAW 264.7细胞中炎性细胞因子的表达和分泌。总体而言,本研究结果为三百棒的抗炎机制的研究提供了新的线索,并为临床更好的应用三百棒治疗炎症性疾病提供理论依据。     

PI3K/AKT信号通路调控Myogenin和MCK基因的表达

骨骼肌分化过程受多个信号通路调控, PI3K/AKT信号通路是其中最重要的信号转导通路之一。PI3K/AKT信号通路可以调控骨骼肌分化, 但在染色质水平上的调控机制还不是很清楚。文章以小鼠成肌细胞(C2C12)为研究材料, 采用免疫印迹、染色质免疫共沉淀(Chromatin immunoprecipitation, ChIP)、定量PCR (Q-PCR)的方法研究PI3K/AKT信号通路调控Myogenin和MCK基因的表达。研究发现, C2C12细胞分化过程中添加PI3K/AKT信号通路激活剂处理24 h, Myogenin和MCK蛋白表达水平显著升高, 组蛋白H3K27me3去甲基化酶UTX的表达也升高, H3K27me3在Myogenin基因启动子区和MCK基因启动子及增强子区的富集与对照组相比显著降低。用PI3K/AKT信号通路抑制剂处理, 结果相反。因此, PI3K/AKT信号通路可能通过调控组蛋白去甲基化酶UTX的表达活性改变靶基因的H3K27me3的富集进而调控骨骼肌分化。     

PI3K/Akt/mTOR信号通路与自噬及肿瘤的关系

自噬是一种以胞质内出现双层膜结构包裹长寿命蛋白和细胞器的自噬体为特征的细胞“自我消化”过程,在维持细胞内稳态、发育、肿瘤发生和感染中发挥重要作用。近来,诸多研究表明,自噬作为一把“双刃剑”,对肿瘤的发生发展既有促进作用,也有抑制作用。PI3K/Akt/mTOR通路由PI3激酶(PI3K)、蛋白激酶B（PKB/Akt）和哺乳动物类雷帕霉素靶蛋白（mTOR）3个作用分子组成,是一个中心的调节机构,对肿瘤细胞的生长与增殖有促进作用,同时对自噬进行抑制。本文就PI3K/Akt/mTOR通路与自噬及肿瘤发生发展的关系作一综述。     

PI3K/AKT信号通路与心力衰竭

丝氨酸/苏氨酸激酶(serine/threonine kinase,AKT)是真核细胞中参与细胞信号转导的关键分子。目前已经证实PI3K(phosphatidylinositol-3-kinase,PI3K)/AKT信号通路在人类肿瘤、代谢紊乱、肾脏疾病以及精神障碍等疾病中发挥着重要的作用。近年来的研究还发现PI3K/AKT信号通路的激活会对心肌细胞的生长、代谢以及凋亡等活动产生影响,且该通路及其中的很多受体、激酶被证实与心力衰竭关系密切,这使该信号通路在心力衰竭的发病机制、诊断及治疗等方面的研究日益受到重视。总结PI3K/AKT的结构特点、相关信号转导机制及其与心力衰竭的关系将有利于更好地理解心力衰竭的发病机制。     

RhoGDI2与PI3K/Akt/mTOR信号通路在肺癌细胞中的相关性研究

目的探讨肿瘤转移相关因子RhoGDI2与PI3K/Akt/mTOR信号通路在肺癌侵袭转移过程中的作用及相关机制。方法利用PI3K/Akt/mTOR信号通路上特异性的抑制剂,采用MTT法,伤口愈合实验及侵袭实验观察不同浓度药物对肺癌95D细胞生长侵袭转移能力的影响,通过Western Blot方法观察RhoGDI2蛋白水平的变化。结果PI3K抑制剂LY294002及mTOR抑制剂Rapamycin都能抑制肺癌细胞95D的侵袭转移能力,联合应用抑制作用更强。PI3K抑制剂LY294002处理组RhoGDI2蛋白的表达量增加,且随浓度增加RhoGDI2蛋白表达也增加。mTOR抑制剂Rapamycin组,在低浓度时增加RhoGDI2蛋白的表达,但增大Rapamycin的浓度,RhoGDI2蛋白的表达反而降低。低浓度LY294002组和Rapa-mycin组联合应用可以明显增加RhoGDI2蛋白的表达。结论PI3K/Akt/mTOR信号通路中Akt的活化与RhoGDI2密切相关,RhoGDI2可能直接或间接通过与Akt的相互作用参与调节肺癌的侵袭转移的过程。     

TGFBI对胃癌MGC-803细胞侵袭转移及血管生成的影响

目的 探讨转化生长因子β诱导物（transforming growth factor β induced, TGFBI）在胃癌中的表达及其对胃癌细胞MGC-803侵袭转移及血管生成的影响和分子机制。方法 RT-q PCR和免疫组织化学检测人胃癌组织及胃癌细胞株中TGFBI的表达。转染小干扰RNA(si-TGFBI)构建人胃癌MGC-803细胞TGFBI敲减模型,MTT实验测定细胞增殖,划痕实验及Transwell侵袭实验评估侵袭转移;Matrigel体外成管实验观察血管生成;免疫荧光及Western blot评估相关目的蛋白的表达及PI3K/AKT/mTOR信号通路的活性。结果 胃癌组织及胃癌细胞株中TGFBI的表达均显著升高。转染si-TGFBI可抑制胃癌MGC-803细胞增殖、血管生成以及侵袭转移,同时上调E-cadherin表达,并下调N-cadherin、Snail以及Vimentin的表达,抑制上皮-间充质转化进程。此外,转染si-TGFBI可显著抑制胃癌MGC-803细胞PI3K/AKT/mTOR信号通路的活性。结论 TGFBI在胃癌中高表达,高表达的TGFBI可能通过激活...     

宫颈癌组织miR-200b-5p、miR-424-5p表达与临床病理特征、PI3K/AKT/mTOR信号通路和预后的关系研究

摘要 目的：探讨宫颈癌组织微小核糖核酸（miRNA）-200b-5p、miR-424-5p表达与临床病理特征、磷脂酰肌醇3-激酶/蛋白激酶B/哺乳动物雷帕霉素靶蛋白（PI3K/AKT/mTOR）信号通路和预后的关系。方法：选取2016年7月～2019年6月西安市中心医院收治的123例宫颈癌患者,采用定量聚合酶链式反应（qPCR）检测癌组织与癌旁组织中miR-200b-5p、miR-424-5p、PI3K信使RNA（mRNA）、AKT mRNA、mTOR mRNA表达。分析miR-200b-5p、miR-424-5p表达与PI3K mRNA、AKT mRNA、mTOR mRNA表达的相关性及与临床病理特征的关系。采用K-M法绘制不同miR-200b-5p、miR-424-5p表达宫颈癌患者生存曲线。结果：与癌旁组织比较,宫颈癌组织中miR-200b-5p、miR-424-5p表达降低,PI3K mRNA、AKT mRNA、mTOR mRNA表达升高（P＜0.05）。Pearson相关性分析显示,宫颈癌组织中miR-200b-5p、miR-424-5p表达与PI3K mRNA、AKT mRNA、mTOR mRNA表达均呈负相关,PI3K mRNA、AKT mRNA、mTOR mRNA表达呈两两相关（P＜0.05）。miR-200b-5p、miR-424-5p表达与宫颈癌分化程度、国际妇产科联盟（FIGO）分期和淋巴结转移有关（P＜0.05）。随访3年,123例宫颈癌患者累积生存率为62.60%（77/123）。K-M生存曲线分析显示,miR-200b-5p、miR-424-5p高表达组累积生存率分别高于miR-200b-5p、miR-424-5p低表达组（P＜0.05）。结论：宫颈癌组织中miR-200b-5p、miR-424-5p低表达,与分化程度、FIGO分期、淋巴结转移、PI3K/AKT/mTOR信号通路和预后有关。     

PI3K/Akt信号通路与肺纤维化

肺纤维化(pulmonary fibrosis)是进行性、致命性的疾病。其致病机制不明,治疗效果差。PI3K/Akt信号通路主要与细胞的生长、增殖、分化、凋亡及血管形成等有关。近年来,随着对PI3K/Akt信号通路的深入研究,发现其活化后可激活下游中的一些因子参与肺纤维化,且与其他通路协同作用促进肺纤维化的形成。因此该通路有可能成为治疗肺纤维化的新靶点。将PI3K/Akt信号通路参与肺纤维化形成的研究进展作一综述。     

PI3K抑制剂LY294002在HPV感染宫颈癌细胞的调节作用

高危型人乳头瘤病毒(Human papiloma virus,HPV)感染是宫颈癌的危险因素,HPV16是常见的高危型HPV,与宫颈癌的发病有关,但具体机制未明确.有临床研究报道,宫颈癌组织中HPV16感染与磷脂酰肌醇-3激酶(PI3K)、蛋白激酶B(AKT)表达增加有关,为了阐明PI3K/AKT信号通路及其抑制剂LY294002在HPV感染宫颈癌细胞增殖中的调控作用,本实验培养了 HPV16感染的宫颈癌细胞株SiHa、HPV阴性的宫颈癌细胞株C33A、正常宫颈上皮细胞株H8,检测了 p-PI3K、p-AKT的表达水平;SiHa细胞分为对照组、50 μmol/L及100 μmol/L LY294002组,药物干预后检测细胞增殖活力A490值及p-PI3K、p-AKT、c-myc、B淋巴细胞瘤-2基因(Bcl-2)的表达水平;皮下注射SiHa细胞建立移植瘤小鼠模型,分为对照组、25mg/kg、50mg/kg LY294002组,药物干预后取移植瘤称重.结果显示,SiHa细胞中p-PI3K、p-AKT的表达水平均高于C33A、H8细胞;50 μmol/L及100 μmol/L LY294002组 SiHa 细胞的 A490值及 p-PI3K、p-AKT、c-myc、bcl-2的表达水平均低于对照组;25 mg/kg、50 mg/kg LY294002组移植瘤小鼠的移植瘤质量均低于对照组(P＜0.05).以上结果表明HPV16感染的宫颈癌细胞中PI3K/AKT信号通路过度激活具有促增殖作用.本实验阐明了 PI3K/AKT通路及其抑制剂LY294002在HPV16感染的宫颈癌细胞增殖中的调控作用,PI3K/AKT通路的激活能够促进HPV16感染的宫颈癌细胞增殖及移植瘤的生长,使用信号通路抑制剂能够抑制细胞增殖及移植瘤生长,未来PI3K/AKT通路可能成为HPV16感染引起宫颈癌的防治靶点.     

Role of regulatory miRNAs of the PI3K/AKT/mTOR signaling in the pathogenesis of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the common malignant human tumors with high morbidity worldwide. Aberrant activation of the oncogenic phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) signaling is related to clinicopathological features of HCC. Emerging data revealed that microRNAs (miRNAs) have prominent implications for regulating cellular proliferation, differentiation, apoptosis, and metabolism through targeting the PI3K/AKT/mTOR signaling axis. The recognition of the crucial role of miRNAs in hepatocarcinogenesis represents a promising area to identify novel anticancer therapeutics for HCC. The present study summarizes the major findings about the regulatory role of miRNAs in the PI3K/AKT/mTOR pathway in the pathogenesis of HCC.     

FGFR1通过调控PI3K/AKT/mTOR信号通路介导非小细胞肺癌对吉非替尼的耐药

目的:探讨成纤维细胞生长因子受体1(FGFR1)诱导非小细胞肺癌(NSCLC)吉非替尼获得性耐药的机制。方法:用吉非替尼诱导PC9细胞构建耐药细胞株PC9/GR,用CCK-8、平板克隆形成、transwell技术检测细胞的增殖和迁移能力,用流式细胞术检测细胞的凋亡状况,qRT-PCR、免疫荧光和蛋白免疫印迹技术检测基因表达水平。进一步采用FGFR1抑制剂PD173074或si RNA-FGFR1处理PC9/GR细胞,检测细胞的增殖、迁移、克隆形成能力的变化及Akt、p-Akt、m TOR和p-mTOR表达的变化。结果:PC9/GR细胞的增殖、迁移及对吉非替尼的耐受能力显著增强;FGFR1在PC9/GR细胞中的表达水平显著升高;用PD173074处理PC9细胞后,其增殖、迁移能力及对吉非替尼的耐受能力显著下降;敲低FGFR1后Akt和m TOR的磷酸化水平显著下降。结论:FGFR1通过PI3K/AKT/mTOR信号通路介导非小细胞肺癌对吉非替尼的耐药。     

Oridonin-induced mitochondria-dependent apoptosis in esophageal cancer cells by inhibiting PI3K/AKT/mTOR and Ras/Raf pathways

Oridonin, an active diterpenoid isolated from Rabdosia rubescens, has been reported for its antitumor activity on several cancers. However, its effect on human esophageal cancer remains unclear. In this study, we demonstrated that oridonin could inhibit the growth of human esophageal cancer cells both in vitro and in vivo. Oridonin not only suppressed the proliferation, but also induced cell cycle arrest and mitochondrial-mediated apoptosis in KYSE-30, KYSE-150, and EC9706 cells with dose-dependent manner. Further mechanism studies revealed that oridonin led cell cycle arrest in esophageal cancer cells via downregulating cell cycle-related proteins, such as cyclin B1 and CDK2, while upregulating p53 and p21. Oridonin also increased proapoptotic protein Bax and reduced antiapoptotic protein Bcl-2, as well as the increased expression of cleaved caspase-3, -8, and -9. In addition, oridonin treatment could significantly inhibit the PI3K/Akt/mTOR and Ras/Raf signaling pathway. In vivo results further demonstrated that oridonin treatment markedly inhibited tumor growth in the esophageal cancer xenograft mice model. Taken together, these results suggest that oridonin may be a potential anticancer agent for the treatment of esophageal cancer.     

Effects of streptozotocin-induced type 1 maternal diabetes on PI3K/AKT signaling pathway in the hippocampus of rat neonates

Diabetes in pregnancy impairs hippocampus development in offspring, leading to behavioral problems and learning deficits. Phosphatidylinositol 3-kinase/protein kinase B (PKB/Akt) signaling pathway plays a pivotal role in the regulation of neuronal proliferation, survival and death. The present study was designed to examine the effects of maternal diabetes on PKB/Akt expression and phosphorylation in the developing rat hippocampus. Wistar female rats were maintained diabetic from a week before pregnancy through parturition and male offspring was killed at first postnatal day (P1). The hippocampal expression and phosphorylation level of PKB/Akt, one of the key molecules in PI3K/AKT signaling pathway, was evaluated using real-time polymerase chain reaction (PCR) and western blot analysis. We found a significant bilateral downregulation of AKT1 gene expression in the hippocampus of pups born to diabetic mothers (p?<?0.05). Interestingly, our results revealed a marked upregulation of Akt1 gene in insulin-treated group compared with other groups (p?<?0.05). The western blot analysis also showed the reduction of phosphorylation level of all AKT isoforms in both diabetic and insulin-treated groups compared with control (p?<?0.05). Moreover, the results showed a significant increase in phosphorylation level of AKT in insulin-treated group compared with the diabetic group. These results represent that diabetes during pregnancy strongly influences the regulation of PKB/AKT in the developing rat hippocampus. Furthermore, although the control of glycemia by insulin administration is not sufficient to prevent the alterations in PKB/Akt expression, it modulates the phosphorylation process, thus ultimately resulting in a situation comparable to that found in the normal condition.     

Feedback loops blockade potentiates apoptosis induction and antitumor activity of a novel AKT inhibitor DC120 in human liver cancer

The serine/threonine kinase AKT is generally accepted as a promising anticancer therapeutic target. However, the relief of feedback inhibition and enhancement of other survival pathways often attenuate the anticancer effects of AKT inhibitors. These compensatory mechanisms are very complicated and remain poorly understood. In the present study, we found a novel 2-pyrimidyl-5-amidothiazole compound, DC120, as an ATP competitive AKT kinase inhibitor that suppressed proliferation and induced apoptosis in liver cancer cells both in vitro and in vivo. DC120 blocked the phosphorylation of downstream molecules in the AKT signal pathway in dose- and time-dependent manners both in vitro and in vivo. However, unexpectedly, DC120 activated mammalian target of rapamycin complex 1 (mTORC1) pathway that was suggested by increased phosphorylation of 70KD ribosomal protein S6 kinase (P70S6K) and eukaryotic translation initiation factor 4E binding protein 1 (4E-BP1). The activated mTORC1 signal was because of increase of intracellular Ca²⁺ via Ca²⁺/calmodulin (CaM)/ signaling to human vacuolar protein sorting 34 (hVps34) upon AKT inhibition. Meanwhile, DC120 attenuated the inhibitory effect of AKT on CRAF by decreasing phosphorylation of CRAF at Ser259 and thus activated the mitogen-activated protein kinase (MAPK) pathway. The activation of the mTORC1 and MAPK pathways by DC120 was not mutually dependent, and the combination of DC120 with mTORC1 inhibitor and/or MEK inhibitor induced significant apoptosis and growth inhibition both in vitro and in vivo. Taken together, the combination of AKT, mTORC1 and/or MEK inhibitors would be a promising therapeutic strategy for liver cancer treatment.     

PLS3 predicts poor prognosis in pancreatic cancer and promotes cancer cell proliferation via PI3K/AKT signaling

Plastin-3 plays a key role in cancer cell proliferation and invasion, but its prognostic value in pancreatic cancer (PACA) remains poorly defined. In this study, we show that PLS3 messenger RNA is overexpressed in PACA tissue compared with normal tissue. We accumulated 207 cases of PACA specimens to perform immunohistochemical analysis and demonstrated that PLS3 levels correlate with T-classification (p < .001) and pathology (p < .001). Furthermore, overall survival rates (p < .001) in tumors with high PLS3 expression were poor, as assessed through Kaplan–Meier survival analysis. PLS3 was found to be an independent prognostic factor for PACA through multivariate Cox regression analysis. Moreover, we found that PLS3 enhances the proliferation and invasion of tumor cells as assessed through Cell Counting Kit-8, wounding healing assays, and Transwell assays. The upregulation of PLS3 also led to enhanced phosphatidylinositol-3 kinase/protein kinase B signaling in PACA cells. These data suggest that PLS3 is a biomarker to estimate PACA progression and represents a molecular target for PACA therapy.     

Autophagy participates in the protection role of 1,25-dihydroxyvitamin D3 in acute myocardial infarction via PI3K/AKT/mTOR pathway

Vitamin D deficiency is associated with acute myocardial infarction (AMI); thus we aimed to explore improvement effects of 1,25-dihydroxyvitamin D3 (VD3) on the AMI and its potential mechanism. AMI models were constructed using male C57/BL6J mice and randomly treated with normal saline or VD3, using sham rats as control. Heart functions, myocardial damage, apoptosis, and inflammation were evaluated. Cardiomyocytes isolated from 3-day-old suckling mice were used for in vitro verification. After VD3 treatment, AMI-induced cardiac dysfunction was reversed with better cardiac function parameters. VD3 treatment reduced inflammatory cell infiltration and myocardial infarction area accompanied by the reduction of inflammatory factors and myocardial infarction markers compared with the AMI group. VD3 treatment obviously alleviated AMI-induced myocardial apoptosis, along with Bcl-2 upregulation and downregulation of caspase-3, caspase-9, and Bax. Both in vivo and in vitro experiments revealed that VD3 enhanced the expression of LC3II and Beclin-1 and decreased soluble p62. Furthermore, VD3 enhanced the AMI-caused inhibition of PI3K, p-AKT, and p-mTOR expression, which was conversely reversed by the addition of 3-methyladenine in vitro. The study highlights the improvement effects of VD3 on cardiac functions. We proposed a potential mechanism that VD3 protects against myocardial damage, inflammation, and apoptosis by promoting autophagy through PI3K/AKT/mTOR pathway.     

利格列汀对小鼠脑缺血/再灌注损伤的神经保护作用*

目的: 评估二肽基肽酶4(DPP-4)抑制剂利格列汀对小鼠脑缺血/再灌注(I/R)损伤的神经保护作用。方法: BALB/c小鼠随机分为Sham组、I/R组和利格列汀(2.5、5和10 mg/kg) +I/R组,每组均为8只小鼠。不同剂量利格列汀组小鼠均在I/R前3周连续灌胃给药。采用小鼠脑中动脉闭塞(MCAO)1 h诱导I/R损伤模型,再灌注24 h评估神经功能缺损(n=8)和及梗死体积(n=4);再灌注48 h处死小鼠,检测脑组织中谷胱甘肽(GSH)、丙二醛(MDA)、磷酸化肌醇3激酶(PI3K)、磷酸化蛋白激酶 B(p-Akt)和雷帕霉素靶蛋白(mTOR)含量(n=4)。结果: 与I/R组相比,利他列汀预处理组小鼠再灌注24 h后,神经功能缺损评分和梗死体积明显降低(P＜0.05);小鼠再灌注48 h后,脑内MDA含量明显降低(P＜0.05),而GSH、PI3K、p-Akt和mTOR水平明显升高(P＜0.05)。结论: 利格列汀对I/R小鼠具有神经保护作用,可能是通过激活PI3K/AKT/mTOR通路发挥的作用。