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.     

PI3K/Akt/mTOR信号传导通路与恶性肿瘤浸润和转移的研究进展

PI3K/Akt/mTOR信号通路作为细胞内重要信号传导通路之一,通过影响下游多种效应分子的活化状态,在细胞内发挥着抑制凋亡、促进增殖的关键作用,它与人类多种肿瘤的发生发展密切相关.本文综述了PI3K/Akt/mTOR信号通路的组成与功能、调节以及其抗肿瘤细胞凋亡作用机理等方面的研究进展,并就其抗细胞凋亡作用在肿瘤治疗中的应用作了评述,期待为以PI3K/Akt/mTOR信号通路中关键分子为靶点的肿瘤治疗研究提供参考.     

PI3K／Akt／inTOR信号传导通路与恶性肿瘤浸润和转移的研究进展

PI3K／Akt／mTOR信号通路作为细胞内重要信号传导通路之一,通过影响下游多种效应分子的活化状态,在细胞内发挥着抑制凋亡、促进增殖的关键作用,它与人类多种肿瘤的发生发展密切相关。本文综述了PI3K／Akt／mTOR信号通路的组成与功能、调节以及其抗肿瘤细胞凋亡作用机理等方面的研究进展,并就其抗细胞凋亡作用在肿瘤治疗中的应用作了评述,期待为以PI3K／Akt／mTOR信号通路中关键分子为靶点的肿瘤治疗研究提供参考。     

ＰＩ３Ｋ／Ａｋｔ信号传导通路及其在结直肠癌中的研究进展

结直肠癌是常见的恶性肿瘤之一,近十年来,结直肠癌在我国的发病率呈逐年上升的趋势。已有研究表明,ＰＩ３Ｋ／Ａｋｔ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。随着ＰＩ３Ｋ／ＡＫｔ信号通路在结直肠癌发生、发展中的研究不断深入,该通路对结直肠癌发生、发展及治疗药物的研发具有十分重要的价值。本文就ＰＩ３Ｋ／Ａｋｔ信号传导通路在结直肠癌发生、发展和治疗中的作用以及机制的研究进展作一综述。     

白藜芦醇联合γ射线调控PI3K/Akt/mTOR信号通路对宫颈癌Hela细胞的影响

目的 探讨白藜芦醇联合γ射线对宫颈癌Hela细胞生物学行为的影响,并对其可能机制进行初步探究。方法 CCK-8法检测不同浓度白藜芦醇溶液 ±γ射线照射后细胞群体增殖;划痕实验和Transwell小室实验检测细胞迁移和侵袭;流式细胞术和Annexin V-FITC/PI双染检测细胞凋亡;蛋白印迹法检测PI3K、Akt、p-Akt、mTOR、p-mTOR蛋白表达。结果 与对照组相比,白藜芦醇组 ±γ射线照射均能抑制细胞增殖、迁移、侵袭能力,并促进细胞凋亡,且联合的效果更加明显。与对照组相比,白藜芦醇和γ射线均能降低细胞中Bcl-2、PI3K、p-Akt、p-mTOR蛋白表达,使Bax蛋白表达上调,但Akt、mTOR蛋白未发生明显改变。结论 白藜芦醇联合γ射线能够明显抑制Hela细胞增殖、迁移、侵袭能力并促进细胞凋亡,其机制可能与PI3K/Akt/mTOR信号通路的抑制作用及下游相关蛋白的表达相关。     

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。     

Effect of BRAF-mediated PI3K/Akt/mTOR pathway on biological characteristics and chemosensitivity of NSCLC A549/DDP cells

The present study aimed to explore the biological characteristics of non-small cell lung cancer (NSCLC) cells and the mechanism of chemosensitivity through the role of the PI3K/Akt/mTOR signaling pathway mediated by BRAF gene silencing. Following cell transfection and grouping, an MTT assay detected the activity of NSCLC cells, a scratch wound test assessed the migration ability, flow cytometry using PI staining detected the cell cycle phase, TUNEL and flow cytometry through Annexin V-PI staining assessed the apoptosis, and colony formation was used to detect the sensitivity of lung cancer cells to cisplatin chemotherapy. Furthermore, the relative expression levels of BRAF, PTEN, PI3K, mTOR mRNA were assessed by RT-qPCR, and the protein expression levels of BRAF, PTEN, PI3K, phosphorylated (p)-PI3K, Akt, p-Akt, mTOR, p-mTOR, cisplatin resistance-related enzymes ERCC1 and BRCA1, apoptotic proteins Bax and Bcl-2 were assessed by western blotting. Compared with the control group and NC group, there were differences in decreased BRAF mRNA expression levels in the small interfering (si)BRAF group and siBRAF + IGF-1 group (both P<0.05). In addition, compared with the control group, the siBRAF, NVP-BEZ235 and siBRAF + NVP-BEZ235 groups had significant decreased cell viability at 2–6 days, decreased migration ability, shortened proportion of S-phase cells, increased proportion of G₁/G₀-phase cells, increased apoptosis rate, decreased number of colony-forming cells, decreased mRNA expression of PI3K, Akt and mTOR, increased PTEN mRNA expression, decreased protein expression levels of PI3K, p-PI3K, Akt, p-Akt, mTOR, p-mTOR, ERCC1, BRCA1 and Bcl-2, and increased protein expression levels of PTEN and Bax (all P<0.05); and more obvious trends were revealed in the siBRAF + NVP-BEZ235 group (all P<0.05); whereas opposite results were detected in the siBRAF + IGF-1 group when compared with the siBRAF group and NVP-BEZ235 group (all P<0.05). Silencing of BRAF gene expression to inhibit the activation of the PI3K/Akt/mTOR signaling pathway exerted a synergistic effect decreasing cell viability, inhibiting the cell cycle and migration, increasing the apoptosis rate, decreasing the number of colony-forming cells and increasing chemosensitivity of NSCLC. Activation of the PI3K/Akt/mTOR signaling pathway may reverse the role of silencing of BRAF gene expression, providing a potential approach for improving the chemosensitivity of NSCLC. The present study for the first time, to the best of our knowledge, clarified the possible mechanism of NSCLC cell biological characteristic changes and chemosensitivity from the perspective of BRAF gene silencing and PI3K/Akt/mTOR signaling pathway activation, providing a potential reference for suppressing tumor aggravation and improving the therapeutic outcomes of NSCLC at the genetic level.     

银杏内酯B通过阻抑PI3K/Akt/mTOR信号通路抑制胃癌HGC-27 细胞的恶性生物学行为

目的：探讨银杏内酯B（GKB）是否通过阻抑PI3K/Akt/mTOR信号通路抑制胃癌HGC-27细胞的增殖、凋亡、迁移及侵袭。方法：将HGC-27细胞分为对照、GKB低剂量（100 mg/L）、GKB高剂量（200 mg/L）、GKB高剂量（200 mg/L）+740Y-P（PI3K激活剂）、Ly294002（PI3K抑制剂）组。采用MTT、Edu、FCM、Transwell实验分别检测各组细胞的增殖、凋亡、迁移和侵袭能力,qPCR和WB法分别检测各组细胞中PI3K mRNA、Akt mRNA、mTOR mRNA和Ki-67、caspase-3、p-PI3K/PI3K、p-Akt/Akt、p-mTOR/mTOR蛋白的表达。构建胃癌HGC-27细胞裸鼠移植瘤模型,观察GKB对移植瘤生长的影响,WB法检测移植瘤组织中Ki-67、caspase-3、p-PI3K/PI3K、p-Akt/Akt、p-mTOR/mTOR蛋白的表达。结果：体外实验结果表明,与对照组相比,GKB低剂量组、GKB高剂量组、Ly294002组HGC-27细胞的增殖活力及细胞增殖率、迁移和侵袭细胞数,PI3K、Akt、mTOR mRNA表达,以及Ki-67、p-PI3K/PI3K、p-Akt/Akt、p-mTOR/mTOR蛋白表达均显著降低（均P<0.05）;细胞凋亡率、caspase-3蛋白表达均显著升高（均P<0.05）;740Y-P可部分逆转GKB对HGC-27细胞的抑制作用（均P<0.05）。荷瘤裸鼠实验结果显示,GKB可显著抑制HGC-27细胞裸鼠移植瘤的生长（P<0.05）,且可下调PI3K/Akt/mTOR通路相关蛋白的表达。结论：GKB可通过阻抑PI3K/Akt/mTOR信号通路而抑制胃癌HGC-27细胞增殖、迁移与侵袭并促进其凋亡。     

基于SNP芯片研究PI3K/Akt/mTOR通路上自噬相关基因SNPs与胃癌的关联

目的： 探讨与胃癌发生相关的PI3K/Akt/mTOR通路上新的与自噬相关基因单核苷酸多态性位点（SNPs），为寻找有价值的胃癌发生相关的分子标志物提供新的依据。方法： 采用1：1配对病例-对照研究的方法。通过KEGG pathway网站和Gene Ontology、Ensemble数据库及HaploView、STRING、Cytoscape软件联合SNP芯片筛选目标SNPs，采用基质辅助激光解吸电离飞行时间质谱（MALDI-TOF-MS）对筛检出来的SNPs位点在来自福建省仙游县的622例胃癌患者和622例健康人群基因组中进行验证。结果： SNP芯片及生物信息学分析筛选出IRS1 rs10205233、PIK3CD rs3934934、PIK3R1 rs706711、PIK3R1 rs706714和AKT1 rs35285446为候选位点。扩大样本验证发现IRS1 rs10205233的多态性变异（C > T）显著降低了胃癌的发病风险[共显性模型、显性模型的OR（95% CI）分别为0.761（0.595，0.975）、0.764（0.601，0.973）]。进一步分层分析，该位点显性模型、隐形模型、共显性模型以及等位基因在贲门癌和非贲门癌人群中均未见统计学差异（P > 0.05）。并未见其他位点与患胃癌风险的关联有统计学意义。对PIK3R1基因2个位点（rs706711、rs706714）的单体型分析也未见统计学差异。结论： IRS1 rs10205233位点与福建省胃癌高发区仙游县的胃癌发生存在关联，T等位基因可能是胃癌发生的一个遗传保护因素。     

PI3K/Akt途径在朊蛋白介导胃癌耐药中的作用研究

目的:探讨PI3K/Akt途径在朊蛋白(PrPc)介导胃癌耐药中的作用.方法:脂质体基因转染法建立高表达PrPc的胃癌细胞亚系.Western印迹检测转染细胞中Akt蛋白的表达.噻唑蓝(MTT) 比色法测定单独或联用PI3K抑制剂LY294002时转染细胞对化疗药物的敏感性.流式细胞仪检测单独或联用LY294002时转染细胞内阿霉素蓄积和潴留.结果:将PrPc正义载体pcDNA-PrP转入SGC7901,成功建立PrPc高表达胃癌细胞亚系并命名为PS;空载体转染细胞命名为BS.Western-Blot显示磷酸化Akt在PS中的表达较BS及SGC7901增高,而三者的总Akt则无差别.未经LY294002处理时,在阿霉素或长春新碱的作用下,PS的存活率分别为91.4%±3.4%和89.4%±3.8%,较BS(79.2%±4.3%和75.9%±2.1%)明显增高(均 ),PS细胞内阿霉素蓄积量和潴留量分别为4.4±0.3和4.2±0.4,明显低于BS(8.2±0.5和8.0±0.3)(均 );当联合LY294002处理后,PS在两种药物作用下的存活率均随着LY294002浓度的增加逐渐降低,并均在LY294002为30μmol/L时接近BS(均 ),PS细胞内阿霉素蓄积量和潴留量逐渐增高,并均在LY294002为30μmol/L时接近BS(均 ).结论:PrPc介导的胃癌耐药与PI3K/ Akt途径活性密切相关,抑制PI3K/ Akt途径活性可逆转PrPc介导的胃癌耐药.     

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.     

MicroRNA-451 regulates stemness of side population cells via PI3K/Akt/mTOR signaling pathway in multiple myeloma

Side population (SP) cells are an enriched source of cancer-initiating cells with stemness characteristics, generated by increased ABC transporter activity, which has served as a unique hallmark for multiple myeloma (MM) stem cell studies. Here we isolated and identified MM SP cells via Hoechst 33342 staining. Furthermore, we demonstrate that SP cells possess abnormal cell cycle, clonogenicity, and high drug efflux characteristics-all of which are features commonly seen in stem cells. Interestingly, we found that bortezomib, As₂O₃, and melphalan all affected apoptosis and clonogenicity in SP cells. We followed by characterizing the miRNA signature of MM SP cells and validated the specific miR-451 target tuberous sclerosis 1 (TSC1) gene to reveal that it activates the PI3K/Akt/mTOR signaling in MM SP cells. Inhibition of miR-451 enhanced anti-myeloma novel agents'' effectiveness, through increasing cells apoptosis, decreasing clonogenicity, and reducing MDR1 mRNA expression. Moreover, the novel specific PI3K/Akt/mTOR signaling inhibitor {"type":"entrez-protein","attrs":{"text":"S14161","term_id":"98844","term_text":"pir||S14161"}}S14161 displayed its prowess as a potential therapeutic agent by targeting MM SP cells. Our findings offer insights into the mechanisms regulating MM SP cells and provide a novel strategy to overcome resistance to existing therapies against myeloma.     

PI3K/Akt/mTOR通路抑制剂对白血病细胞株增殖及其PHLPP表达的影响

目的:观察PI3K/Akt/mTOR通路抑制剂wortmannin或rapamycin对白血病细胞株增殖及其PHLPP(PH domainleucine-rich repeat protein phosphatase)蛋白表达的影响。方法:以不同浓度的wortmannin或rapamycin分别作用于人类髓细胞白血病细胞系K562、HL-60,采用WST-1法检测细胞的增殖活性,AnnexinⅤ-FITC双染流式细胞术检测细胞凋亡,Westernblotting法检测细胞中p-Akt、Akt、PHLPP蛋白的表达。结果:Wortmannin以时间以及剂量依赖方式抑制K562、HL-60细胞的增殖(P<0.05),48 h的IC50值分别为(187.6±48.4)、(185.5±48.1)nmol/L。100 nmol/L wortmannin作用于K562细胞、50nmol/L wortmannin作用于HL-60细胞12和24 h后,细胞凋亡率均较对照细胞显著升高[(12.4±0.7)%、(17.6±2.3)%vs(5.0±0.6)%,P<0.05;(11.0±0.2)%、(17.9±1.6)%vs(6.8±0.4)%,P<0.05]。Wortmannin分别作用于K562、HL-60细胞12、24、36 h后,p-Akt、PHLPP的蛋白表达水平明显降低;rapamycin同样可使K562、HL-60细胞中PHLPP蛋白的表达水平降低。结论:PI3K/Akt/mTOR信号通路抑制剂抑制白血病细胞株增殖的同时降低其PHLPP蛋白的表达。     

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。     

PTEN promoter methylation and activation of the PI3K/Akt/mTOR pathway in pediatric gliomas and influence on clinical outcome

The signaling pathways that underlie the pathogenesis of pediatric gliomas are poorly understood. We characterized the PI3K/Akt/mTOR pathway in pediatric gliomas of all grades. Using immunohistochemistry, we assessed activation of the PI3K/Akt/mTOR pathway by evaluating the downstream signaling molecules phospho(p)-S6, phospho(p)-4BP1, and phospho(p)-PRAS40; PTEN; and PTEN promoter methylation, as well as the MIB labeling index. We correlated these findings with the clinical outcomes of 48 children with gliomas. Eighty percent of high-grade gliomas (12/15) showed activation of the PI3K/Akt/mTOR pathway based on p-S6 and p-4EBP1 expression. The majority of high-grade gliomas were negative for PTEN expression (10/15), and 50% had PTEN promoter methylation (grade III: 2/4; grade IV: 3/6). Low-grade gliomas demonstrated PI3K/Akt/mTOR pathway activation in 14/32 (43.8%) by p-S6 and 16/32 (50%) by p-4EBP1. Over 50% of grade I (6/11) and almost all grade II tumors (6/7) showed PTEN promoter methylation. Tumor grade correlated negatively with PTEN expression and positively with expression of p-S6 and p-4EBP1 (PTEN: P = .0025; pS6: P = .0075; p-4EBP1: P = .0066). There was a trend toward inverse correlation of methylation of the PTEN promoter with expression of PTEN protein (P= .0990) and direct correlation of expression of p-S6 and p-4EBP1 with poorer clinical outcome, as measured by progression-free survival (p-S6: P= .0874; p-4EBP1: P= .0475). Tumors with no PTEN expression had a higher MIB labeling index (P= .007). The majority of pediatric gliomas show activation of the PI3K/Akt/mTOR pathway, with methylation of the PTEN promoter occurring commonly in these tumors.