PI3K/AKT/mTOR信号通路及其在卵巢癌治疗中的应用

卵巢癌是女性生殖系统常见的恶性肿瘤,发病率居于妇科恶性肿瘤第三位,死亡率居于妇科恶性肿瘤之首。目前对卵巢癌的标准治疗包括肿瘤细胞减灭术及卡铂和紫杉醇的联合化疗。PI3K/AKT/mTOR信号通路在卵巢癌的细胞增殖、侵袭、细胞周期进展、血管生成及耐药中发挥重要作用,是卵巢癌中最常发生改变的细胞内途径。本文对PI3K/AKT/mTOR信号通路及其在卵巢癌增殖和进展中的影响、PI3K/AKT/mTOR信号通路抑制剂在卵巢癌中的治疗应用做简要综述。     

PI3K/AKT/mTOR信号通路在骨肉瘤中的作用

骨肉瘤是儿童和青少年最常见的非血液病性骨恶性肿瘤.在骨肉瘤的发生机制中,PI3K/AKT/mTOR信号通路可通过调控细胞周期进程、抑制细胞凋亡、促进血管形成,进而参与骨肉瘤的增殖、侵袭和转移.在骨肉瘤组织和细胞中PI3K/AKT/mTOR信号通路常被异常激活,促进了骨肉瘤的快速发展.本文就PI3K/AKT/mTOR信号...     

mTOR/S6K1信号通路与胰岛素抵抗的关系及有氧运动对其影响的研究

目的:通过研究高脂饮食和有氧运动对胰岛素抵抗(IR)小鼠骨骼肌雷帕霉素靶蛋白/核糖体S6激酶1(mTOR/S6K1)通路的影响,试图为运动防治IR提供理论依据。方法:8周C57BL/6小鼠随机分为正常饮食组和高脂饮食组,每组各20只,高脂饮食组喂养8周后建立IR模型。随后将正常饮食组再次随机分为正常饮食安静组(NC)和正常饮食运动组(NE);高脂饮食组也随机分为高脂饮食安静组(HC)和高脂饮食运动组(HE)。各运动组进行为期6周、75%VO2max强度跑台训练,每天1次,每次60min,每周5次。实验结束后采用OGTT检测葡萄糖耐量,组织学检测胰岛形态变化,ELISA法检测血清空腹胰岛素水平,Northern blot、Western blot检测骨骼肌中mTOR和S6K1 mRNA和蛋白及其磷酸化蛋白pS6K1-Thr389的表达。结果:与NC组相比,HC组小鼠体重、空腹血清胰岛素值和胰岛β细胞团面积百分比均呈显著增加,且OGTT曲线显示糖耐量明显受损,然而6周有氧运动后以上各指标呈显著性降低,葡萄糖耐量也得到明显改善;且骨骼肌中mTOR、S6K1、pS6K1-Thr389 mRNA和蛋白表达均明显降低。结论:mTOR/S6K1信号通路与高脂饮食诱导IR的发生密切相关,有氧运动明显增加了机体组织对胰岛素的敏感性,推测有氧运动可能通过抑制mTOR/S6K1信号通路,增加IR小鼠骨骼肌的能量代谢从而改善IR。     

miR-20a靶向CCND1作用PI3K/AKT信号通路抑制皮肤鳞状细胞癌的发展

摘要 目的：探究miR-20a与CCND1蛋白在皮肤鳞状细胞癌（CSCC）中的作用关系,以及其可能涉及的信号通路分子机制。方法：分别收集皮肤鳞状细胞癌患者的皮肤癌组织及其邻近正常皮肤组织,采用qRT-PCR分析组织中miR-20a和CCND1基因表达水平。为探究miR-20a对CSCC细胞的影响,将SCL-1细胞分为对照组（不转染）、miR-NC组（转染miR-NC）和miR-20a mimics组（转染miR-20a mimics）;为探究CCND1与PI3K/AKT信号通路的关系,将SCL-1细胞分为对照组（不转染）、si-NC组（转染si-NC）和si-CCND1组（转染si-CCND1）;为探究miR-20a与CCND1间的作用关系及对CSCC细胞的影响,将SCL-1细胞分为miR-NC组（转染miR-NC）、miR-20a mimics组（转染miR-20a mimics）、mimics+pcDNA组（共转染miR-20a mimics和pcDNA）和mimics+CCND1组（共转染miR-20a mimics和pcDNA-CCND1）。采用Western blot分析p-AKT、AKT、p-PI3K、PI3K和GSK-3β蛋白表达水平;采用MTT检测细胞增殖情况;采用流式细胞术检测细胞凋亡情况;采用Transwell分析细胞迁移和侵袭情况;采用双荧光素酶报告基因检测分析miR-20a与CCND1的靶向关系。结果：CSCC癌组织和SCL-1中miR-20a均低表达,CCND1高表达。与对照组和miR-NC组比较,miR-20a mimics组SCL-1细胞增殖水平以及侵袭和迁移数量均降低（P<0.05）,SCL-1细胞凋亡水平升高（P<0.05）,PI3K和AKT蛋白磷酸化水平降低（P<0.05）。TargetScanHuman数据库分析和双荧光素酶报告基因检测结果显示miR-20a与CCND1存在靶向作用关系。与对照组和si-NC组比较,si-CCND1组SCL-1细胞中CCND1和GSK-3β蛋白表达水平以及PI3K和AKT蛋白磷酸化水平均降低（P<0.01）。与miR-20a mimics组或mimics+pcDNA组比较,mimics+CCND1组SCL-1细胞增殖水平以及侵袭和迁移数量均升高（P<0.05）,SCL-1细胞凋亡水平降低（P<0.05）,PI3K和AKT蛋白磷酸化水平均升高（P<0.05）。结论：过表达miR-20a可能通过靶向抑制CCND1的表达而抑制PI3K/AKT信号通路的激活,从而抑制CSCC细胞的增殖、侵袭和迁移,并促进癌细胞凋亡。     

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。     

NEAT1通过PI3K/AKT/Bcl-2信号通路抑制骨质疏松

为探讨NEAT1在骨质疏松症中的作用以及可能的病理机制,本研究通过建立卵巢去势和鼠尾悬挂2种骨质疏松的小鼠模型,将C57BL/6分为假手术组(Sham组)、OVX组和TS组;经过PCR测定小鼠NEAT1的表达;Elisa法检测小鼠E2、ALP和TRACP水平;Western blotting检测细胞凋亡因子PI3K/AKT/Bcl-2的蛋白水平。结果显示,建模4周后,3组小鼠体重没有显著变化;与Sham组相比,OVX组和TS组小鼠的骨密度值显著降低,骨生化指标ALP和TRACR水平明显升高;OVX组小鼠的E2水平与Sham组相比明显降低;与Sham组相比,OVX组和TS组小鼠的NEAT1表达显著下调;与Sham组相比,OVX组和TS组小鼠p-AKT和Bcl-2蛋白水平明显降低。本研究结果表明,NEAT1可能通过抑制PI3K/AKT/Bcl-2细胞凋亡途径诱导骨质疏松。     

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信号传导通路对鼻咽癌细胞增殖和凋亡的影响

目的研究PI3K/AKT信号传导途径对人低分化鼻咽癌细胞系在CNE-2Z生长、增殖和凋亡的作用。方法应用wort mannin抑制PI3K的活性,绘制生长曲线、MTT观察wort mannin对CNE-2Z细胞生长、增殖的作用,以免疫细胞化学分别检测wort mannin处理培养后的CNE-2Z细胞中PI3K、AKT和bcl-2的表达,RT-PCR检测wort mannin处理后的细胞bcl-2 mRNA的表达情况,ELISA法检测wort mannin处理后的CNE-2Z细胞中的磷酸化的AKT的含量,流式细胞仪检测wort mannin处理培养后的CNE-2Z细胞的凋亡。结果 wort mannin对CNE-2Z细胞生长、增殖具有抑制作用,而且呈剂量依赖性。wort mannin作用后CNE-2Z细胞的PI3K和bcl-2的蛋白表达均减弱,而AKT的表达无明显变化。wort-mannin抑制CNE-2Z细胞bcl-2 mRNA的表达。wort mannin能显著抑制磷酸化的AKT的表达,并呈一定的剂量依赖性。Wort mannin还可以诱导CNE-2Z细胞的凋亡。结论 PI3K的抑制剂wort mannin可以有效抑制鼻咽癌CNE-2Z细胞的生长和增殖,诱导CNE-2Z细胞凋亡。     

Regulation of survivin by PI3K/Akt/p70S6K1 pathway

PI3K activation is commonly observed in many human cancer cells. Survivin expression is elevated in cancer cells, and induced by some growth factors through PI3K activation. However, it is not clear whether PI3K activation is sufficient to induce survivin expression. To investigate the role of PI3K pathway in the regulation of survivin, we expressed an active form of PI3K, v-P3k in chicken embryonic fibroblast cells (CEF), and found that overexpression of PI3K-induced survivin mRNA expression. Forced expression of wild-type but not mutant tumor suppressor PTEN in CEF decreased survivin mRNA levels. PI3K regulates survivin expression through Akt activation. To further investigate downstream target of PI3K and Akt in regulating the expression of survivin mRNA, we found that PI3K and Akt-induced p70S6K1 activation and that overexpression of p70S6K1 alone was sufficient to induce survivin expression. The treatment of CEF cells by rapamycin decreased the survivin mRNA expression. This result demonstrated that p70S6K1 is an important target downstream of PI3K and Akt in regulating suvivin mRNA expression. The knockdown of survivin mRNA expression by its specific siRNA induced apoptosis of cancer cells when the cells were treated with LY294002 or taxol. Taken together, these results demonstrated that PI3K/Akt/p70S6K1 pathway is essential for regulating survivin mRNA expression.     

Mollugin induces tumor cell apoptosis and autophagy via the PI3K/AKT/mTOR/p70S6K and ERK signaling pathways

Mollugin, a bioactive phytochemical isolated from Rubia cordifolia L., has shown preclinical anticancer efficacy in various cancer models. However the effects of mollugin in regulating cancer cell survival and death remains undefined. In the present study we found that mollugin exhibited cytotoxicity on various cancer models. The suppression of cell viability was due to the induction of mitochondria apoptosis. In addition, the presence of autophagic hallmarks was observed in mollugin-treated cells. Notably, blockade of autophagy by a chemical inhibitor or RNA interference enhanced the cytotoxicity of mollugin. Further experiments demonstrated that phosphatidylinositide 3-kinases/protein kinase B/mammalian target of rapamycin/p70S6 kinase (PI3K/AKT/mTOR/p70S6K) and extracellular regulated protein kinases (ERK) signaling pathways participated in mollugin-induced autophagy and apoptosis. Together, these findings support further studies of mollugin as candidate for treatment of human cancer cells.     

Role of PI3K and AKT specific isoforms in ovarian cancer cell migration, invasion and proliferation through the p70S6K1 pathway

Ovarian cancer is the leading cause of death from gynecological malignancy for women. The amplification of the PI3K catalytic subunit (p110) and the lost function of PTEN are frequently detected in ovarian cancer cells. PI3K plays an important role in tumorigenesis. To specifically inhibit PI3K activity in ovarian cancer cells, we constructed small interfering RNA (siRNA) against p110. The expression of p110 siRNA significantly decreased cell migration, invasion, and proliferation compared to the siSCR control cells. The expression of p110 siRNA induced CDK inhibitor p27^KIP1 levels, and decreased levels of cyclin D1, CDK4, and phosphorylated retinoblastoma protein. PI3K transmits the mytogenic signal through AKT. AKT has three isoforms in the cells: AKT1, AKT2 and AKT3. We found that inhibition of AKT1 is sufficient to affect cell migration, invasion, and proliferation. Expression of AKT1 siRNA had a similar effect as p110 siRNA in the cells. We showed the roles of specific PI3K and AKT isoforms in the cells, which are important to understanding the mechanism of PI3K/AKT signaling in ovarian cancer cells. Both p110 and AKT1 siRNA-expressing cells decreased the activation of p70S6K1. Inhibition of p70S6K1 activity by its siRNA also decreased cell migration, invasion, and proliferation associated with the induction of p27^KIP1 levels, and with the inhibition of cell cycle-associated proteins including cyclin D1, CDK2, and phosphorylated retinoblastoma protein. This study demonstrates the important role of the PI3K/AKT/mTOR/p70S6K1 pathway in cell proliferation, migration, and invasion in ovarian cancer cells by using siRNA-mediated gene silencing as a reverse genetic method.     

Resveratrol suppresses the epithelial-to-mesenchymal transition in PC-3 cells by down-regulating the PI3K/AKT signaling pathway

Resveratrol possesses a wide spectrum of pharmacological properties and has been an ideal alternative drug for the treatment of different cancers, including prostate cancer. However, the mechanisms by which resveratrol inhibits the growth of prostate cancer are still not fully elucidated. To understand the effect of resveratrol on the apoptosis and the epithelial-to-mesenchymal transition (EMT) of prostate cancer as well as its related mechanism, we investigated the potential use of resveratrol in PC-3 prostate cancer cells in vitro using real-time PCR, fluorescence-activated cell sorting, Western blotting, etc. Resveratrol suppresses the PC-3 prostate cancer cell growth and induces apoptosis. Resveratrol also influences the expression of EMT-related proteins (increased E-cadherin and decreased Vimentin expression). Finally, resveratrol also suppressed Akt phosphorylation in PC-3 cells. This study indicates that resveratrol may be a potential anti-cancer treatment for prostate cancer; moreover, it provides new evidence that resveratrol suppresses prostate cancer growth and metastasis.     

The KMT1A/TIMP3/PI3K/AKT circuit regulates tumor growth in cervical cancer

The epigenetic mechanism of tissue inhibitor of metalloproteinase 3 (TIMP3), a well-known tumor suppressor, in cervical cancer (CC) is still unclear. Integrated GEO database, protein interaction network, and a pan-cancer analysis revealed a KMT1A/TIMP3 axis in CC. KMT1A was highly expressed, and TIMP3 was poorly expressed in CC tissues and cells. KMT1A inhibited the activity of TIMP3. Silencing of KMT1A hampered the proliferation, migration, invasion, tumorigenesis and metastases of CC cells in vivo, and increased the apoptosis of cells. TIMP3 downregulation promoted the malignant phenotype and in vivo tumorigenesis and metastasis of CC cells. KMT1A downregulation impaired PI3K/AKT pathway in cells, while TIMP3 silencing promoted PI3K/AKT pathway activity. We propose a novel perspective that KMT1A involves in the growth and metastases via the TIMP3/PI3K/AKT axis in CC. In summary, our study identified a vital role played by KMT1A in the development of CC and the epigenetic mechanism, indicating that targeting KMT1A-related pathways could be conducive to the therapies for CC.     

Yak OXGR1 promotes fibroblast proliferation via the PI3K/AKT pathways

Oxoglutarate receptor 1 (OXGR1), as one of the intermediates in G protein-coupled receptors (GPCRs), plays a crucial role in the citric acid cycle receptor of α-ketoglutarate and metabolism. GPCR can control the cell proliferation by regulating the downstream signaling of G protein signaling pathways. The PI3K/AKT pathway transmits the downstream signals of GPCRs and receptor tyrosine kinases. However, the specific role of OXGR1 promoting cell proliferation and differentiation are still unknown. In current study, the over-expression vector and knockdown sequence of yak OXGR1 were transfected into yak fibroblasts, and the effects were detected by a series of assays. The results revealed that OXGR1 expression in yak lung parenchyma tissue was significantly higher than that of other tissues. In yak fibroblasts, the upregulated expression of OXGR1 resulted in activating the PIK3CG (downstream signal) of the PI3K/AKT1 pathway that can upregulated the expression of proliferation genes ( CDK1, PCNA, and CyclinD1) and promote cell proliferation. Conversely, the downregulated expression of OXGR1 inhibited cell proliferation via PI3K/AKT1 pathway. Cell cycle and cell proliferation assays demonstrated that over-expression of OXGR1 can enhanced the DNA synthesis and promoted yak fibroblasts proliferation. While the conversely, knockdown of OXGR1 can decreased DNA synthesis and inhibited cell proliferation. These results illustrated that changes of OXGR1 expression can trigger the fibroblasts proliferation via PI3K/AKT signaling pathway, which indicating that OXGR1 is a novel regulator for cell proliferation and differentiation. Furthermore, these results provide evidence supporting the functional role of GPCRs-PI3K-AKT1 and OXGR1 in cell proliferation.