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Sample records for 3-kinase pi 3-k

  1. Icaritin requires Phosphatidylinositol 3 kinase (PI3K)/Akt signaling to counteract skeletal muscle atrophy following mechanical unloading

    PubMed Central

    ZHANG, Zong-Kang; LI, Jie; LIU, Jin; GUO, Baosheng; LEUNG, Albert; ZHANG, Ge; ZHANG, Bao-Ting

    2016-01-01

    Counteracting muscle atrophy induced by mechanical unloading/inactivity is of great clinical need and challenge. A therapeutic agent that could counteract muscle atrophy following mechanical unloading in safety is desired. This study showed that natural product Icaritin (ICT) could increase the phosphorylation level of Phosphatidylinositol 3 kinase (PI3K) at p110 catalytic subunit and promote PI3K/Akt signaling markers in C2C12 cells. This study further showed that the high dose ICT treatment could significantly attenuate the decreases in the phosphorylation level of PI3K at p110 catalytic subunit and its downstream markers related to protein synthesis, and inhibit the increases in protein degradation markers at mRNA and protein levels in rat soleus muscle following 28-day hindlimb unloading. In addition, the decreases in soleus muscle mass, muscle fiber cross-sectional area, twitch force, specific force, contraction time and half relaxation time could be significantly attenuated by the high dose ICT treatment. The low dose ICT treatment could moderately attenuate the above changes induced by unloading. Wortmannin, a specific inhibitor of PI3K at p110 catalytic subunit, could abolish the above effects of ICT in vitro and in vivo, indicating that PI3K/Akt signaling could be required by ICT to counteract skeletal muscle atrophy following mechanical unloading. PMID:26831566

  2. Shiga toxin type-2 (Stx2) induces glutamate release via phosphoinositide 3-kinase (PI3K) pathway in murine neurons

    PubMed Central

    Obata, Fumiko; Hippler, Lauren M.; Saha, Progyaparamita; Jandhyala, Dakshina M.; Latinovic, Olga S.

    2015-01-01

    Shiga toxin-producing Escherichia coli (STEC) can cause central nervous system (CNS) damage resulting in paralysis, seizures, and coma. The key STEC virulence factors associated with systemic illness resulting in CNS impairment are Shiga toxins (Stx). While neurons express the Stx receptor globotriaosylceramide (Gb3) in vivo, direct toxicity to neurons by Stx has not been studied. We used murine neonatal neuron cultures to study the interaction of Shiga toxin type 2 (Stx2) with cell surface expressed Gb3. Single molecule imaging three dimensional STochastic Optical Reconstruction Microscopy—Total Internal Reflection Fluorescence (3D STORM-TIRF) allowed visualization and quantification of Stx2-Gb3 interactions. Furthermore, we demonstrate that Stx2 increases neuronal cytosolic Ca2+, and NMDA-receptor inhibition blocks Stx2-induced Ca2+ influx, suggesting that Stx2-mediates glutamate release. Phosphoinositide 3-kinase (PI3K)-specific inhibition by Wortmannin reduces Stx2-induced intracellular Ca2+ indicating that the PI3K signaling pathway may be involved in Stx2-associated glutamate release, and that these pathways may contribute to CNS impairment associated with STEC infection. PMID:26236186

  3. A Switch of G Protein-Coupled Receptor Binding Preference from Phosphoinositide 3-Kinase (PI3K)–p85 to Filamin A Negatively Controls the PI3K Pathway

    PubMed Central

    Najib, Souad; Saint-Laurent, Nathalie; Estève, Jean-Pierre; Schulz, Stefan; Boutet-Robinet, Elisa; Fourmy, Daniel; Lättig, Jens; Mollereau, Catherine; Pyronnet, Stéphane; Susini, Christiane

    2012-01-01

    Frequent oncogenic alterations occur in the phosphoinositide 3-kinase (PI3K) pathway, urging identification of novel negative controls. We previously reported an original mechanism for restraining PI3K activity, controlled by the somatostatin G protein-coupled receptor (GPCR) sst2 and involving a ligand-regulated interaction between sst2 with the PI3K regulatory p85 subunit. We here identify the scaffolding protein filamin A (FLNA) as a critical player regulating the dynamic of this complex. A preexisting sst2-p85 complex, which was shown to account for a significant basal PI3K activity in the absence of ligand, is disrupted upon sst2 activation. FLNA was here identified as a competitor of p85 for direct binding to two juxtaposed sites on sst2. Switching of GPCR binding preference from p85 toward FLNA is determined by changes in the tyrosine phosphorylation of p85- and FLNA-binding sites on sst2 upon activation. It results in the disruption of the sst2-p85 complex and the subsequent inhibition of PI3K. Knocking down FLNA expression, or abrogating FLNA recruitment to sst2, reversed the inhibition of PI3K and of tumor growth induced by sst2. Importantly, we report that this FLNA inhibitory control on PI3K can be generalized to another GPCR, the mu opioid receptor, thereby providing an unprecedented mechanism underlying GPCR-negative control on PI3K. PMID:22203038

  4. Role of phosphoinositide 3-kinase IA (PI3K-IA) activation in cardioprotection induced by ouabain preconditioning.

    PubMed

    Duan, Qiming; Madan, Namrata D; Wu, Jian; Kalisz, Jennifer; Doshi, Krunal Y; Haldar, Saptarsi M; Liu, Lijun; Pierre, Sandrine V

    2015-03-01

    Acute myocardial infarction, the clinical manifestation of ischemia-reperfusion (IR) injury, is a leading cause of death worldwide. Like ischemic preconditioning (IPC) induced by brief episodes of ischemia and reperfusion, ouabain preconditioning (OPC) mediated by Na/K-ATPase signaling protects the heart against IR injury. Class I PI3K activation is required for IPC, but its role in OPC has not been investigated. While PI3K-IB is critical to IPC, studies have suggested that ouabain signaling is PI3K-IA-specific. Hence, a pharmacological approach was used to test the hypothesis that OPC and IPC rely on distinct PI3K-I isoforms. In Langendorff-perfused mouse hearts, OPC was initiated by 4 min of ouabain 10 μM and IPC was triggered by 4 cycles of 5 min ischemia and reperfusion prior to 40 min of global ischemia and 30 min of reperfusion. Without affecting PI3K-IB, ouabain doubled PI3K-IA activity and Akt phosphorylation at Ser(473). IPC and OPC significantly preserved cardiac contractile function and tissue viability as evidenced by left ventricular developed pressure and end-diastolic pressure recovery, reduced lactate dehydrogenase release, and decreased infarct size. OPC protection was blunted by the PI3K-IA inhibitor PI-103, but not by the PI3K-IB inhibitor AS-604850. In contrast, IPC-mediated protection was not affected by PI-103 but was blocked by AS-604850, suggesting that PI3K-IA activation is required for OPC while PI3K-IB activation is needed for IPC. Mechanistically, PI3K-IA activity is required for ouabain-induced Akt activation but not PKCε translocation. However, in contrast to PKCε translocation which is critical to protection, Akt activity was not required for OPC. Further studies shall reveal the identity of the downstream targets of this new PI3K IA-dependent branch of OPC. These findings may be of clinical relevance in patients at risk for myocardial infarction with underlying diseases and/or medication that could differentially affect the

  5. Infectious bursal disease virus activates the phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway by interaction of VP5 protein with the p85{alpha} subunit of PI3K

    SciTech Connect

    Wei Li; Hou Lei; Zhu Shanshan; Wang Jing; Zhou Jiao; Liu Jue

    2011-08-15

    Phosphatidylinositol 3-kinase (PI3K)/Akt signaling is commonly activated upon virus infection and has been implicated in the regulation of diverse cellular functions such as proliferation and apoptosis. The present study demonstrated for the first time that infectious bursal disease virus (IBDV), the causative agent of a highly contagious disease in chickens, can induce Akt phosphorylation in cultured cells, by a mechanism that is dependent on PI3K. Inhibition of PI3K activation greatly enhanced virus-induced cytopathic effect and apoptotic cell death as evidenced by cleavage of poly-ADP ribose polymerase and activation of caspase-3. Investigations into the mechanism of PI3K/Akt activation revealed that IBDV activates PI3K/Akt signaling through binding of the non-structural protein VP5 to regulatory subunit p85{alpha} of PI3K resulting in the suppression of premature apoptosis and improved virus growth after infection. The results presented here provide a basis for understanding molecular mechanism of IBDV infection.

  6. p87 and p101 subunits are distinct regulators determining class IB phosphoinositide 3-kinase (PI3K) specificity.

    PubMed

    Shymanets, Aliaksei; Prajwal; Bucher, Kirsten; Beer-Hammer, Sandra; Harteneck, Christian; Nürnberg, Bernd

    2013-10-25

    Class IB phosphoinositide 3-kinase γ (PI3Kγ) comprises a single catalytic p110γ subunit, which binds to two non-catalytic subunits, p87 or p101, and controls a plethora of fundamental cellular responses. The non-catalytic subunits are assumed to be redundant adaptors for Gβγ enabling G-protein-coupled receptor-mediated regulation of PI3Kγ. Growing experimental data provide contradictory evidence. To elucidate the roles of the non-catalytic subunits in determining the specificity of PI3Kγ, we tested the impact of p87 and p101 in heterodimeric p87-p110γ and p101-p110γ complexes on the modulation of PI3Kγ activity in vitro and in living cells. RT-PCR, biochemical, and imaging data provide four lines of evidence: (i) specific expression patterns of p87 and p101, (ii) up-regulation of p101, providing the basis to consider p87 as a protein forming a constitutively and p101 as a protein forming an inducibly expressed PI3Kγ, (iii) differences in basal and stimulated enzymatic activities, and (iv) differences in complex stability, all indicating apparent diversity within class IB PI3Kγ. In conclusion, expression and activities of PI3Kγ are modified differently by p87 and p101 in vitro and in living cells, arguing for specific regulatory roles of the non-catalytic subunits in the differentiation of PI3Kγ signaling pathways. PMID:24014027

  7. Targeting the phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) pathway: an emerging treatment strategy for squamous cell lung carcinoma.

    PubMed

    Beck, Joseph Thaddeus; Ismail, Amen; Tolomeo, Christina

    2014-09-01

    Squamous cell lung carcinoma accounts for approximately 30% of all non-small cell lung cancers (NSCLCs). Despite progress in the understanding of the biology of cancer, cytotoxic chemotherapy remains the standard of care for patients with squamous cell lung carcinoma, but the prognosis is generally poor. The phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) pathway is one of the most commonly activated signaling pathways in cancer, leading to cell proliferation, survival, and differentiation. It has therefore become a major focus of clinical research. Various alterations in the PI3K/AKT/mTOR pathway have been identified in squamous cell lung carcinoma and a number of agents targeting these alterations are in clinical development for use as single agents and in combination with other targeted and conventional treatments. These include pan-PI3K inhibitors, isoform-specific PI3K inhibitors, AKT inhibitors, mTOR inhibitors, and dual PI3K/mTOR inhibitors. These agents have demonstrated antitumor activity in preclinical models of NSCLC and preliminary clinical evidence is also available for some agents. This review will discuss the role of the PI3K/AKT/mTOR pathway in cancer and how the discovery of genetic alterations in this pathway in patients with squamous cell lung carcinoma can inform the development of targeted therapies for this disease. An overview of ongoing clinical trials investigating PI3K/AKT/mTOR pathway inhibitors in squamous cell lung carcinoma will also be included.

  8. Different inhibition of Gβγ-stimulated class IB phosphoinositide 3-kinase (PI3K) variants by a monoclonal antibody

    PubMed Central

    Shymanets, Aliaksei; Prajwal; Vadas, Oscar; Czupalla, Cornelia; LoPiccolo, Jaclyn; Brenowitz, Michael; Ghigo, Alessandra; Hirsch, Emilio; Krause, Eberhard; Wetzker, Reinhard; Williams, Roger L.; Harteneck, Christian; Nürnberg, Bernd

    2015-01-01

    Class IB phosphoinositide 3-kinases (PI3Kγ) are second-messenger-generating enzymes downstream of signalling cascades triggered by G-protein-coupled-receptors (GPCRs). PI3Kγ variants have one catalytic p110γ subunit that can form two different heterodimers by binding to one of a pair of non-catalytic subunits, p87 or p101. Growing experimental data argue for a different regulation of p87-p110γ and p101-p110γ allowing integration into distinct signalling pathways. Pharmacological tools enabling distinct modulation of the two variants are missing. The ability of an anti-p110γ monoclonal antibody (mAb(A)p110γ) to block PI3Kγ enzymatic activity attracted us to characterize this tool in detail using purified proteins. In order to get insight into the antibody-p110γ-interface, hydrogen-deuterium exchange coupled to mass spectrometry measurements were performed demonstrating binding of the monoclonal antibody to the C2 domain in p110γ, which was accompanied by conformational changes in the helical domain harbouring the Gβγ-binding site. We then studied the modulation of phospholipid vesicles association of PI3Kγ by the antibody. p87-p110γ showed a significantly reduced Gβγ-mediated phospholipid recruitment as compared with p101-p110γ. Concomitantly, in the presence of mAb(A)p110γ Gβγ did not bind to p87-p110γ. These data correlated with the ability of the antibody to block Gβγ-stimulated lipid kinase activity of p87-p110γ 30 times more potently than p101-p110γ. Our data argue for differential regulatory functions of the non-catalytic subunits and a specific Gβγ-dependent regulation of p101 in PI3Kγ activation. In this scenario, we consider the antibody as a valuable tool to dissect the distinct roles of the two PI3Kγ variants downstream of GPCRs. PMID:26173259

  9. Fine particulate matter leads to reproductive impairment in male rats by overexpressing phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway.

    PubMed

    Cao, Xi-Ning; Yan, Chao; Liu, Dong-Yao; Peng, Jin-Pu; Chen, Jin-Jun; Zhou, Yue; Long, Chun-Lan; He, Da-Wei; Lin, Tao; Shen, Lian-Ju; Wei, Guang-Hui

    2015-09-17

    Maintenance of male reproductive function depends on normal sperm generation during which process Sertoli cells play a vital role. Studies found that fine particulate matter (PM) causes decreased male sperm quality, mechanism of which unestablished. We aim to investigate the definite mechanism of PM impairment on male reproduction. Male Sprague-Dawley rats were daily exposed to normal saline (NS) or PM2.5 with the doses of 9 mg/kg.b.w and 24 mg/kg.b.w. via intratracheal instillation for seven weeks. Reproductive function was tested by mating test and semen analysis after last exposure. Testes were collected to assess changes in histomorphology, and biomarkers including connexin 43 (Cx43), superoxide dismutase (SOD), phosphatidylinositol 3-kinase (PI3K) and phosphorylated protein kinase B (p-Akt). Male rats exposed to PM2.5 showed noticeable decreased fertility, significantly reduced sperm count, increased sperm abnormality rate and severe testicular damage in histomorphology. After PM2.5 exposure, the levels of Cx43 was significantly downregulated, and SOD was upregulated and downregulated significantly with different dose, respectively. Protein expression of PI3K and p-Akt dramatically enhanced, and the later one being located in Sertoli cells, the upward or declining trend was in dose dependent. PM2.5 exposure leads to oxidative stress impairment via PI3K/Akt signaling pathway on male reproduction in rats.

  10. Optimization of the phenylurea moiety in a phosphoinositide 3-kinase (PI3K) inhibitor to improve water solubility and the PK profile by introducing a solubilizing group and ortho substituents.

    PubMed

    Kawada, Hatsuo; Ebiike, Hirosato; Tsukazaki, Masao; Yamamoto, Shun; Koyama, Kohei; Nakamura, Mitsuaki; Morikami, Kenji; Yoshinari, Kiyoshi; Yoshida, Miyuki; Ogawa, Kotaro; Shimma, Nobuo; Tsukuda, Takuo; Ohwada, Jun

    2016-07-01

    Phosphoinositide 3-kinase (PI3K) is a promising anti-cancer target, because various mutations and amplifications are observed in human tumors isolated from cancer patients. Our dihydropyrrolopyrimidine derivative with a phenylurea moiety showed strong PI3K enzyme inhibitory activity, but its pharmacokinetic property was poor because of lack of solubility. Herein, we report how we improved the solubility of our PI3K inhibitors by introducing a solubilizing group and ortho substituents to break molecular planarity. PMID:27189888

  11. Discovery of a Selective Phosphoinositide-3-Kinase (PI3K)-γ Inhibitor (IPI-549) as an Immuno-Oncology Clinical Candidate.

    PubMed

    Evans, Catherine A; Liu, Tao; Lescarbeau, André; Nair, Somarajan J; Grenier, Louis; Pradeilles, Johan A; Glenadel, Quentin; Tibbitts, Thomas; Rowley, Ann M; DiNitto, Jonathan P; Brophy, Erin E; O'Hearn, Erin L; Ali, Janid A; Winkler, David G; Goldstein, Stanley I; O'Hearn, Patrick; Martin, Christian M; Hoyt, Jennifer G; Soglia, John R; Cheung, Culver; Pink, Melissa M; Proctor, Jennifer L; Palombella, Vito J; Tremblay, Martin R; Castro, Alfredo C

    2016-09-01

    Optimization of isoquinolinone PI3K inhibitors led to the discovery of a potent inhibitor of PI3K-γ (26 or IPI-549) with >100-fold selectivity over other lipid and protein kinases. IPI-549 demonstrates favorable pharmacokinetic properties and robust inhibition of PI3K-γ mediated neutrophil migration in vivo and is currently in Phase 1 clinical evaluation in subjects with advanced solid tumors. PMID:27660692

  12. Better Understanding of Phosphoinositide 3-Kinase (PI3K) Pathways in Vasculature: Towards Precision Therapy Targeting Angiogenesis and Tumor Blood Supply.

    PubMed

    Tsvetkov, D; Shymanets, A; Huang, Yu; Bucher, K; Piekorz, R; Hirsch, E; Beer-Hammer, S; Harteneck, C; Gollasch, M; Nürnberg, B

    2016-07-01

    The intracellular PI3K-AKT-mTOR pathway is involved in regulation of numerous important cell processes including cell growth, differentiation, and metabolism. The PI3Kα isoform has received particular attention as a novel molecular target in gene therapy, since this isoform plays critical roles in tumor progression and tumor blood flow and angiogenesis. However, the role of PI3Kα and other class I isoforms, i.e. PI3Kβ, γ, δ, in the regulation of vascular tone and regional blood flow are largely unknown. We used novel isoform-specific PI3K inhibitors and mice deficient in both PI3Kγ and PI3Kδ (Pik3cg(-/-)/Pik3cd(-/-)) to define the putative contribution of PI3K isoform(s) to arterial vasoconstriction. Wire myography was used to measure isometric contractions of isolated murine mesenteric arterial rings. Phenylephrine-dependent contractions were inhibited by the pan PI3K inhibitors wortmannin (100 nM) and LY294002 (10 µM). These vasoconstrictions were also inhibited by the PI3Kα isoform inhibitors A66 (10 µM) and PI-103 (1 µM), but not by the PI3Kβ isoform inhibitor TGX 221 (100 nM). Pik3cg(-/-)/Pik3cd(-/-)-arteries showed normal vasoconstriction. We conclude that PI3Kα is an important downstream element in vasoconstrictor GPCR signaling, which contributes to arterial vasocontraction via α1-adrenergic receptors. Our results highlight a regulatory role of PI3Kα in the cardiovascular system, which widens the spectrum of gene therapy approaches targeting PI3Kα in cancer cells and tumor angiogenesis and regional blood flow. PMID:27449615

  13. Phospshoinositide 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) dual inhibitors: discovery and structure-activity relationships of a series of quinoline and quinoxaline derivatives.

    PubMed

    Nishimura, Nobuko; Siegmund, Aaron; Liu, Longbin; Yang, Kevin; Bryan, Marian C; Andrews, Kristin L; Bo, Yunxin; Booker, Shon K; Caenepeel, Sean; Freeman, Daniel; Liao, Hongyu; McCarter, John; Mullady, Erin L; San Miguel, Tisha; Subramanian, Raju; Tamayo, Nuria; Wang, Ling; Whittington, Douglas A; Zalameda, Leeanne; Zhang, Nancy; Hughes, Paul E; Norman, Mark H

    2011-07-14

    The phosphoinositide 3-kinase (PI3K) family catalyzes the ATP-dependent phosphorylation of the 3'-hydroxyl group of phosphatidylinositols and plays an important role in cell growth and survival. There is abundant evidence demonstrating that PI3K signaling is dysregulated in many human cancers, suggesting that therapeutics targeting the PI3K pathway may have utility for the treatment of cancer. Our efforts to identify potent, efficacious, and orally available PI3K/mammalian target of rapamycin (mTOR) dual inhibitors resulted in the discovery of a series of substituted quinolines and quinoxalines derivatives. In this report, we describe the structure-activity relationships, selectivity, and pharmacokinetic data of this series and illustrate the in vivo pharmacodynamic and efficacy data for a representative compound.

  14. Phosphatidylinositol-3-kinase (PI3K) is activated by influenza virus vRNA via the pathogen pattern receptor Rig-I to promote efficient type I interferon production.

    PubMed

    Hrincius, Eike R; Dierkes, Rüdiger; Anhlan, Darisuren; Wixler, Viktor; Ludwig, Stephan; Ehrhardt, Christina

    2011-12-01

    The phosphatidylinositol-3-kinase (PI3K) was identified to be activated upon influenza A virus (IAV) infection. An early and transient induction of PI3K signalling is caused by viral attachment to cells and promotes virus entry. In later phases of infection the kinase is activated by the viral NS1 protein to prevent premature apoptosis. Besides these virus supporting functions, it was suggested that PI3K signalling is involved in dsRNA and IAV induced antiviral responses by enhancing the activity of interferon regulatory factor-3 (IRF-3). However, molecular mechanisms of activation remained obscure. Here we show that accumulation of vRNA in cells infected with influenza A or B viruses results in PI3K activation. Furthermore, expression of the RNA receptors Rig-I and MDA5 was increased upon stimulation with virion extracted vRNA or IAV infection. Using siRNA approaches, Rig-I was identified as pathogen receptor necessary for influenza virus vRNA sensing and subsequent PI3K activation in a TRIM25 and MAVS signalling dependent manner. Rig-I induced PI3K signalling was further shown to be essential for complete IRF-3 activation and consequently induction of the type I interferon response. These data identify PI3K as factor that is activated as part of the Rig-I mediated anti-pathogen response to enhance expression of type I interferons.

  15. Berberine Induced Apoptosis of Human Osteosarcoma Cells by Inhibiting Phosphoinositide 3 Kinase/Protein Kinase B (PI3K/Akt) Signal Pathway Activation

    PubMed Central

    2016-01-01

    Background: Osteosarcoma is a malignant tumor with high mortality but effective therapy has not yet been developed. Berberine, an isoquinoline alkaloid component in several Chinese herbs including Huanglian, has been shown to induce growth inhibition and the apoptosis of certain cancer cells. The aim of this study was to determine the role of berberine on human osteosarcoma cell lines U2OS and its potential mechanism. Methods: The proliferation effect of U20S was exanimed by 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di- phenytetrazoliumromide (MTT) and the percentage of apoptotic cells were determined by flow cytometric analysis. The expression of PI3K, p-Akt, Bax, Bcl-2, cleavage-PARP and Caspase3 were detected by Western blott. Results: Berberine treatment caused dose-dependent inhibiting proliferation and inducing apoptosis of U20S cell. Mechanistically, berberine inhibits PI3K/AKT activation that, in turn, results in up-regulating the expression of Bax, and PARP and down-regulating the expression of Bcl-2 and caspase3. In all, berberine can suppress the proliferation and induce the apoptosis of U2OS cell through inhibiting the PI3K/Akt signaling pathway activation. Conclusion: Berberine can suppress the proliferation and induce the apoptosis of U2OS cell through inhibiting the PI3K/Akt signaling pathway activation. PMID:27398330

  16. Predicting the structures of complexes between phosphoinositide 3-kinase (PI3K) and romidepsin-related compounds for the drug design of PI3K/histone deacetylase dual inhibitors using computational docking and the ligand-based drug design approach.

    PubMed

    Oda, Akifumi; Saijo, Ken; Ishioka, Chikashi; Narita, Koichi; Katoh, Tadashi; Watanabe, Yurie; Fukuyoshi, Shuichi; Takahashi, Ohgi

    2014-11-01

    Predictions of the three-dimensional (3D) structures of the complexes between phosphoinositide 3-kinase (PI3K) and two inhibitors were conducted using computational docking and the ligand-based drug design approach. The obtained structures were refined by structural optimizations and molecular dynamics (MD) simulations. The ligands were located deep inside the ligand binding pocket of the p110α subunit of PI3K, and the hydrogen bond formations and hydrophobic effects of the surrounding amino acids were predicted. Although rough structures were obtained for the PI3K-inhibitor complexes before the MD simulations, the refinement of the structures by these simulations clarified the hydrogen bonding patterns of the complexes.

  17. Phosphoinositide 3-Kinase (PI3K) Subunit p110δ Is Essential for Trophoblast Cell Differentiation and Placental Development in Mouse

    PubMed Central

    Hu, Xiwen; Li, Jiangchao; Zhang, Qianqian; Zheng, Lingyun; Wang, Guang; Zhang, Xiaohan; Zhang, Jingli; Gu, Quliang; Ye, Yuxiang; Guo, Sun-Wei; Yang, Xuesong; Wang, Lijing

    2016-01-01

    Maternal PI3K p110δ has been implicated in smaller litter sizes in mice, but its underlying mechanism remains unclear. The placenta is an indispensable chimeric organ that supports mammalian embryonic development. Using a mouse model of genetic inactivation of PI3K p110δ (p110δD910A/D910A), we show that fetuses carried by p110δD910A/D910A females were growth retarded and showed increased mortality in utero mainly during placentation. The placentas in p110δD910A/D910A females were anomalously anemic, exhibited thinner spongiotrophoblast layer and looser labyrinth zone, which indicate defective placental vasculogenesis. In addition, p110δ was detected in primary trophoblast giant cells (P-TGC) at early placentation. Maternal PI3K p110δ inactivation affected normal TGCs generation and expansion, impeded the branching of chorioallantoic placenta but enhanced the expression of matrix metalloproteinases (MMP-2, MMP-12). Poor vasculature support for the developing fetoplacental unit resulted in fetal death or gross growth retardation. These data, taken together, provide the first in vivo evidence that p110δ may play an important role in placental vascularization through manipulating trophoblast giant cell. PMID:27306493

  18. Involvement of phosphoinositide 3-kinase class IA (PI3K 110α) and NADPH oxidase 1 (NOX1) in regulation of vascular differentiation induced by vascular endothelial growth factor (VEGF) in mouse embryonic stem cells.

    PubMed

    Bekhite, Mohamed M; Müller, Veronika; Tröger, Sebastian H; Müller, Jörg P; Figulla, Hans-Reiner; Sauer, Heinrich; Wartenberg, Maria

    2016-04-01

    The impact of reactive oxygen species and phosphoinositide 3-kinase (PI3K) in differentiating embryonic stem (ES) cells is largely unknown. Here, we show that the silencing of the PI3K catalytic subunit p110α and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 1 (NOX1) by short hairpin RNA or pharmacological inhibition of NOX and ras-related C3 botulinum toxin substrate 1 (Rac1) abolishes superoxide production by vascular endothelial growth factor (VEGF) in mouse ES cells and in ES-cell-derived fetal liver kinase-1(+) (Flk-1(+)) vascular progenitor cells, whereas the mitochondrial complex I inhibitor rotenone does not have an effect. Silencing p110α or inhibiting Rac1 arrests vasculogenesis at initial stages in embryoid bodies, even under VEGF treatment, as indicated by platelet endothelial cell adhesion molecule-1 (PECAM-1)-positive areas and branching points. In the absence of p110α, tube-like structure formation on matrigel and cell migration of Flk-1(+) cells in scratch migration assays are totally impaired. Silencing NOX1 causes a reduction in PECAM-1-positive areas, branching points, cell migration and tube length upon VEGF treatment, despite the expression of vascular differentiation markers. Interestingly, silencing p110α but not NOX1 inhibits the activation of Rac1, Ras homologue gene family member A (RhoA) and Akt leading to the abrogation of VEGF-induced lamellipodia structure formation. Thus, our data demonstrate that the PI3K p110α-Akt/Rac1 and NOX1 signalling pathways play a pivotal role in VEGF-induced vascular differentiation and cell migration. Rac1, RhoA and Akt phosphorylation occur downstream of PI3K and upstream of NOX1 underscoring a role of PI3K p110α in the regulation of cell polarity and migration. PMID:26553657

  19. E6 variants of human papillomavirus 18 differentially modulate the protein kinase B/phosphatidylinositol 3-kinase (akt/PI3K) signaling pathway

    SciTech Connect

    Contreras-Paredes, Adriana

    2009-01-05

    Intra-type genome variations of high risk Human papillomavirus (HPV) have been associated with a differential threat for cervical cancer development. In this work, the effect of HPV18 E6 isolates in Akt/PKB and Mitogen-associated protein kinase (MAPKs) signaling pathways and its implication in cell proliferation were analyzed. E6 from HPV types 16 and 18 are able to bind and promote degradation of Human disc large (hDlg). Our results show that E6 variants differentially modulate hDlg degradation, rebounding in levels of activated PTEN and PKB. HPV18 E6 variants are also able to upregulate phospho-PI3K protein, strongly correlating with activated MAPKs and cell proliferation. Data was supported by the effect of E6 silencing in HPV18-containing HeLa cells, as well as hDlg silencing in the tested cells. Results suggest that HPV18 intra-type variations may derive in differential abilities to activate cell-signaling pathways such as Akt/PKB and MAPKs, directly involved in cell survival and proliferation.

  20. Susi, a negative regulator of Drosophila PI3-kinase.

    PubMed

    Wittwer, Franz; Jaquenoud, Malika; Brogiolo, Walter; Zarske, Marcel; Wüstemann, Philipp; Fernandez, Rafael; Stocker, Hugo; Wymann, Matthias P; Hafen, Ernst

    2005-06-01

    The Phosphatidylinositol-3 kinase/Protein Kinase B (PI3K/PKB) signaling pathway controls growth, metabolism, and lifespan in animals, and deregulation of its activity is associated with diabetes and cancer in humans. Here, we describe Susi, a coiled-coil domain protein that acts as a negative regulator of insulin signaling in Drosophila. Whereas loss of Susi function increases body size, overexpression of Susi reduces growth. We provide genetic evidence that Susi negatively regulates dPI3K activity. Susi directly binds to dP60, the regulatory subunit of dPI3K. Since Susi has no overt similarity to known inhibitors of PI3K/PKB signaling, it defines a novel mechanism by which this signaling cascade is kept in check. The fact that Susi is expressed in a circadian rhythm, with highest levels during the night, suggests that Susi attenuates insulin signaling during the fasting period.

  1. First-in-human Phase I study of Pictilisib (GDC-0941), a potent pan-class I phosphatidylinositol-3-kinase (PI3K) inhibitor, in patients with advanced solid tumors

    PubMed Central

    Baird, Richard; Kristeleit, Rebecca; Shah, Krunal; Moreno, Victor; Clarke, Paul A.; Raynaud, Florence I.; Levy, Gallia; Ware, Joseph A; Mazina, Kathryn; Lin, Ray; Wu, Jenny; Fredrickson, Jill; Spoerke, Jill M; Lackner, Mark R; Yan, Yibing; Friedman, Lori S.; Kaye, Stan B.; Derynck, Mika K.; Workman, Paul; de Bono, Johann S.

    2014-01-01

    Purpose This first-in-human dose-escalation trial evaluated the safety, tolerability, maximal tolerated dose (MTD), dose limiting toxicities (DLTs), pharmacokinetics, pharmacodynamics and preliminary clinical activity of pictilisib (GDC-0941), an oral, potent and selective inhibitor of the Class I phosphatidylinositol-3-kinases (PI3K). Patients and Methods Sixty patients with solid tumors received pictilisib at 14 dose levels from 15 to 450mg once-daily, initially on days 1-21 every 28 days and later, utilizing continuous dosing for selected dose levels. Pharmacodynamic studies incorporated 18F-FDG-PET, and assessment of phosphorylated AKT and S6 ribosomal protein in platelet-rich plasma and tumor tissue. Results Pictilisib was well-tolerated. The most common toxicities were grade 1-2 nausea, rash and fatigue while the DLT was grade 3 maculopapular rash (450mg, 2 of 3 patients; 330mg, 1 of 7 patients). The pharmacokinetic profile was dose-proportional and supported once-daily dosing. Levels of phosphorylated serine-473 AKT were suppressed >90% in platelet rich plasma at 3 hours post-dose at the MTD and in tumor at pictilisib doses associated with AUC >20uM.hr. Significant increase in plasma insulin and glucose levels, and >25% decrease in 18F-FDG uptake by PET in 7 of 32 evaluable patients confirmed target modulation. A patient with V600E BRAF mutant melanoma and another with platinum-refractory epithelial ovarian cancer exhibiting PTEN loss and PIK3CA amplification demonstrated partial response by RECIST and GCIG-CA125 criteria, respectively. Conclusion Pictilisib was safely administered with a dose-proportional pharmacokinetic profile, on-target pharmacodynamic activity at dose levels ≥100mg and signs of antitumor activity. The recommended Phase II dose was continuous dosing at 330mg once-daily. PMID:25370471

  2. Class I PI 3-kinases: Function and evolution.

    PubMed

    Kriplani, Nisha; Hermida, Miguel A; Brown, Euan R; Leslie, Nicholas R

    2015-09-01

    In many human cell types, the class I phosphoinositide 3-kinases play key roles in the control of diverse cellular processes including growth, proliferation, survival and polarity. This is achieved through their activation by many cell surface receptors, leading to the synthesis of the phosphoinositide lipid signal, PIP3, which in turn influences the function of numerous direct PIP3-binding proteins. Here we review PI3K pathway biology and analyse the evolutionary distribution of its components and their functions. The broad phylogenetic distribution of class I PI3Ks in metazoa, amoebozoa and choannoflagellates, implies that these enzymes evolved in single celled organisms and were later co-opted into metazoan intercellular communication. A similar distribution is evident for the AKT and Cytohesin groups of downstream PIP3-binding proteins, with other effectors and pathway components appearing to evolve later. The genomic and functional phylogeny of regulatory systems such as the PI3K pathway provides a framework to improve our understanding of the mechanisms by which key cellular processes are controlled in humans.

  3. PI3K signaling supports amphetamine-induced dopamine efflux.

    PubMed

    Lute, Brandon J; Khoshbouei, Habibeh; Saunders, Christine; Sen, Namita; Lin, Richard Z; Javitch, Jonathan A; Galli, Aurelio

    2008-08-01

    The dopamine (DA) transporter (DAT) is a major molecular target of the psychostimulant amphetamine (AMPH). AMPH, as a result of its ability to reverse DAT-mediated inward transport of DA, induces DA efflux thereby increasing extracellular DA levels. This increase is thought to underlie the behavioral effects of AMPH. We have demonstrated previously that insulin, through phosphatidylinositol 3-kinase (PI3K) signaling, regulates DA clearance by fine-tuning DAT plasma membrane expression. PI3K signaling may represent a novel mechanism for regulating DA efflux evoked by AMPH, since only active DAT at the plasma membrane can efflux DA. Here, we show in both a heterologous expression system and DA neurons that inhibition of PI3K decreases DAT cell surface expression and, as a consequence, AMPH-induced DA efflux.

  4. Ras-related C3 Botulinum Toxin Substrate (Rac) and Src Family Kinases (SFK) Are Proximal and Essential for Phosphatidylinositol 3-Kinase (PI3K) Activation in Natural Killer (NK) Cell-mediated Direct Cytotoxicity against Cryptococcus neoformans.

    PubMed

    Xiang, Richard F; Stack, Danuta; Huston, Shaunna M; Li, Shu Shun; Ogbomo, Henry; Kyei, Stephen K; Mody, Christopher H

    2016-03-25

    The activity of Rac in leukocytes is essential for immunity. However, its role in NK cell-mediated anti-microbial signaling remains unclear. In this study, we investigated the role of Rac in NK cell mediated anti-cryptococcal killing. We found thatCryptococcus neoformansindependently activates both Rac and SFK pathways in NK cells, and unlike in tumor killing,Cryptococcusinitiated a novel Rac → PI3K → Erk cytotoxicity cascade. Remarkably, Rac was not required for conjugate formation, despite its essential role in NK cytotoxicity againstC. neoformans Taken together, our data show that, unlike observations with tumor cells, NK cells use a novel Rac cytotoxicity pathway in conjunction with SFK, to killC. neoformans. PMID:26867574

  5. Ras-related C3 Botulinum Toxin Substrate (Rac) and Src Family Kinases (SFK) Are Proximal and Essential for Phosphatidylinositol 3-Kinase (PI3K) Activation in Natural Killer (NK) Cell-mediated Direct Cytotoxicity against Cryptococcus neoformans.

    PubMed

    Xiang, Richard F; Stack, Danuta; Huston, Shaunna M; Li, Shu Shun; Ogbomo, Henry; Kyei, Stephen K; Mody, Christopher H

    2016-03-25

    The activity of Rac in leukocytes is essential for immunity. However, its role in NK cell-mediated anti-microbial signaling remains unclear. In this study, we investigated the role of Rac in NK cell mediated anti-cryptococcal killing. We found thatCryptococcus neoformansindependently activates both Rac and SFK pathways in NK cells, and unlike in tumor killing,Cryptococcusinitiated a novel Rac → PI3K → Erk cytotoxicity cascade. Remarkably, Rac was not required for conjugate formation, despite its essential role in NK cytotoxicity againstC. neoformans Taken together, our data show that, unlike observations with tumor cells, NK cells use a novel Rac cytotoxicity pathway in conjunction with SFK, to killC. neoformans.

  6. Nerve growth factor (NGF) regulates activity of nuclear factor of activated T-cells (NFAT) in neurons via the phosphatidylinositol 3-kinase (PI3K)-Akt-glycogen synthase kinase 3β (GSK3β) pathway.

    PubMed

    Kim, Man-Su; Shutov, Leonid P; Gnanasekaran, Aswini; Lin, Zhihong; Rysted, Jacob E; Ulrich, Jason D; Usachev, Yuriy M

    2014-11-01

    The Ca(2+)/calcineurin-dependent transcription factor nuclear factor of activated T-cells (NFAT) plays an important role in regulating many neuronal functions, including excitability, axonal growth, synaptogenesis, and neuronal survival. NFAT can be activated by action potential firing or depolarization that leads to Ca(2+)/calcineurin-dependent dephosphorylation of NFAT and its translocation to the nucleus. Recent data suggest that NFAT and NFAT-dependent functions in neurons can also be potently regulated by NGF and other neurotrophins. However, the mechanisms of NFAT regulation by neurotrophins are not well understood. Here, we show that in dorsal root ganglion sensory neurons, NGF markedly facilitates NFAT-mediated gene expression induced by mild depolarization. The effects of NGF were not associated with changes in [Ca(2+)]i and were independent of phospholipase C activity. Instead, the facilitatory effect of NGF depended on activation of the PI3K/Akt pathway downstream of the TrkA receptor and on inhibition of glycogen synthase kinase 3β (GSK3β), a protein kinase known to phosphorylate NFAT and promote its nuclear export. Knockdown or knockout of NFATc3 eliminated this facilitatory effect. Simultaneous monitoring of EGFP-NFATc3 nuclear translocation and [Ca(2+)]i changes in dorsal root ganglion neurons indicated that NGF slowed the rate of NFATc3 nuclear export but did not affect its nuclear import rate. Collectively, our data suggest that NGF facilitates depolarization-induced NFAT activation by stimulating PI3K/Akt signaling, inactivating GSK3β, and thereby slowing NFATc3 export from the nucleus. We propose that NFAT serves as an integrator of neurotrophin action and depolarization-driven calcium signaling to regulate neuronal gene expression.

  7. Adaptive Mitochondrial Reprogramming and Resistance to PI3K Therapy

    PubMed Central

    Ghosh, Jagadish C.; Siegelin, Markus D.; Vaira, Valentina; Faversani, Alice; Tavecchio, Michele; Chae, Young Chan; Lisanti, Sofia; Rampini, Paolo; Giroda, Massimo; Caino, M. Cecilia; Seo, Jae Ho; Kossenkov, Andrew V.; Michalek, Ryan D.; Schultz, David C.; Bosari, Silvano; Languino, Lucia R.

    2015-01-01

    Background: Small molecule inhibitors of phosphatidylinositol-3 kinase (PI3K) have been developed as molecular therapy for cancer, but their efficacy in the clinic is modest, hampered by resistance mechanisms. Methods: We studied the effect of PI3K therapy in patient-derived tumor organotypic cultures (from five patient samples), three glioblastoma (GBM) tumor cell lines, and an intracranial model of glioblastoma in immunocompromised mice (n = 4–5 mice per group). Mechanisms of therapy-induced tumor reprogramming were investigated in a global metabolomics screening, analysis of mitochondrial bioenergetics and cell death, and modulation of protein phosphorylation. A high-throughput drug screening was used to identify novel preclinical combination therapies with PI3K inhibitors, and combination synergy experiments were performed. All statistical methods were two-sided. Results: PI3K therapy induces global metabolic reprogramming in tumors and promotes the recruitment of an active pool of the Ser/Thr kinase, Akt2 to mitochondria. In turn, mitochondrial Akt2 phosphorylates Ser31 in cyclophilin D (CypD), a regulator of organelle functions. Akt2-phosphorylated CypD supports mitochondrial bioenergetics and opposes tumor cell death, conferring resistance to PI3K therapy. The combination of a small-molecule antagonist of CypD protein folding currently in preclinical development, Gamitrinib, plus PI3K inhibitors (PI3Ki) reverses this adaptive response, produces synergistic anticancer activity by inducing mitochondrial apoptosis, and extends animal survival in a GBM model (vehicle: median survival = 28.5 days; Gamitrinib+PI3Ki: median survival = 40 days, P = .003), compared with single-agent treatment (PI3Ki: median survival = 32 days, P = .02; Gamitrinib: median survival = 35 days, P = .008 by two-sided unpaired t test). Conclusions: Small-molecule PI3K antagonists promote drug resistance by repurposing mitochondrial functions in bioenergetics and cell survival. Novel

  8. PI3K inhibitors for cancer therapy: what has been achieved so far?

    PubMed

    Wu, Peng; Liu, Tao; Hu, Yongzhou

    2009-01-01

    PI3K is a large duel lipid and protein kinase that catalyzes phosphorylation of the 3-hydroxyl position of phosphatidylinositides (PIs) and plays a crucial role in the cellular signaling network. Inhibition of the phosphatidylinositol 3-kinase (PI3K) signaling pathway is a newly identified strategy for the discovery and development of certain therapeutic agents. Among the various subtypes of PI3K, class IA PI3Kalpha has gained increasing attention as a promising drug target for the treatment of cancer due to its frequent mutations and amplifications in various human cancers. Here, we discuss the insights gained so far relevant to the development of PI3K inhibitors for the treatment of human cancers. Emphasis is on the structure-activity relationship of PI3K inhibitors which bear the most significant PI3Kalpha inhibitory activities. We also highlight PI3K inhibitors that are currently under clinical trials for cancers. PMID:19275602

  9. Endothelial PI 3-kinase activity regulates lymphocyte diapedesis.

    PubMed

    Nakhaei-Nejad, Maryam; Hussain, Amer M; Zhang, Qiu-Xia; Murray, Allan G

    2007-12-01

    Lymphocyte recruitment to sites of inflammation involves a bidirectional series of cues between the endothelial cell (EC) and the leukocyte that culminate in lymphocyte migration into the tissue. Remodeling of the EC F-actin cytoskeleton has been observed after leukocyte adhesion, but the signals to the EC remain poorly defined. We studied the dependence of peripheral blood lymphocyte transendothelial migration (TEM) through an EC monolayer in vitro on EC phosphatidylinositol 3-kinase (PI 3-kinase) activity. Lymphocytes were perfused over cytokine-activated EC using a parallel-plate laminar flow chamber. Inhibition of EC PI 3-kinase activity using LY-294002 or wortmannin decreased lymphocyte TEM (48 +/- 6 or 34 +/- 7%, respectively, vs. control; mean +/- SE; P < 0.05). Similarly, EC knockdown of the p85alpha regulatory subunit of PI 3-kinase decreased lymphocyte transmigration. Treatment of EC with jasplakinolide to inhibit EC F-actin remodeling also decreased lymphocyte TEM to 24 +/- 10% vs. control (P < 0.05). EC PI 3-kinase inhibition did not change the strength of lymphocyte adhesion to the EC or formation of the EC "docking structure" after intercellular adhesion molecule-1 ligation, whereas this was inhibited by jasplakinolide treatment. A similar fraction of lymphocytes migrated on control or LY-294002-treated EC and localized to interendothelial junctions. However, lymphocytes failed to extend processes below the level of vascular endothelial (VE)-cadherin on LY-294002-treated EC. Together these observations indicate that EC PI 3-kinase activity and F-actin remodeling are required during lymphocyte diapedesis and identify a PI 3-kinase-dependent step following initial separation of the VE-cadherin barrier.

  10. PI3K/Akt signalling pathway and cancer.

    PubMed

    Fresno Vara, Juan Angel; Casado, Enrique; de Castro, Javier; Cejas, Paloma; Belda-Iniesta, Cristóbal; González-Barón, Manuel

    2004-04-01

    Phosphatidylinositol-3 kinases, PI3Ks, constitute a lipid kinase family characterized by their ability to phosphorylate inositol ring 3'-OH group in inositol phospholipids to generate the second messenger phosphatidylinositol-3,4,5-trisphosphate (PI-3,4,5-P(3)). RPTK activation results in PI(3,4,5)P(3) and PI(3,4)P(2) production by PI3K at the inner side of the plasma membrane. Akt interacts with these phospholipids, causing its translocation to the inner membrane, where it is phosphorylated and activated by PDK1 and PDK2. Activated Akt modulates the function of numerous substrates involved in the regulation of cell survival, cell cycle progression and cellular growth. In recent years, it has been shown that PI3K/Akt signalling pathway components are frequently altered in human cancers. Cancer treatment by chemotherapy and gamma-irradiation kills target cells primarily by the induction of apoptosis. However, the development of resistance to therapy is an important clinical problem. Failure to activate the apoptotic programme represents an important mode of drug resistance in tumor cells. Survival signals induced by several receptors are mediated mainly by PI3K/Akt, hence this pathway may decisively contribute to the resistant phenotype. Many of the signalling pathways involved in cellular transformation have been elucidated and efforts are underway to develop treatment strategies that target these specific signalling molecules or their downstream effectors. The PI3K/Akt pathway is involved in many of the mechanisms targeted by these new drugs, thus a better understanding of this crossroad can help to fully exploit the potential benefits of these new agents. PMID:15023437

  11. Ethosuximide Induces Hippocampal Neurogenesis and Reverses Cognitive Deficits in an Amyloid-β Toxin-induced Alzheimer Rat Model via the Phosphatidylinositol 3-Kinase (PI3K)/Akt/Wnt/β-Catenin Pathway.

    PubMed

    Tiwari, Shashi Kant; Seth, Brashket; Agarwal, Swati; Yadav, Anuradha; Karmakar, Madhumita; Gupta, Shailendra Kumar; Choubey, Vinay; Sharma, Abhay; Chaturvedi, Rajnish Kumar

    2015-11-20

    Neurogenesis involves generation of new neurons through finely tuned multistep processes, such as neural stem cell (NSC) proliferation, migration, differentiation, and integration into existing neuronal circuitry in the dentate gyrus of the hippocampus and subventricular zone. Adult hippocampal neurogenesis is involved in cognitive functions and altered in various neurodegenerative disorders, including Alzheimer disease (AD). Ethosuximide (ETH), an anticonvulsant drug is used for the treatment of epileptic seizures. However, the effects of ETH on adult hippocampal neurogenesis and the underlying cellular and molecular mechanism(s) are yet unexplored. Herein, we studied the effects of ETH on rat multipotent NSC proliferation and neuronal differentiation and adult hippocampal neurogenesis in an amyloid β (Aβ) toxin-induced rat model of AD-like phenotypes. ETH potently induced NSC proliferation and neuronal differentiation in the hippocampus-derived NSC in vitro. ETH enhanced NSC proliferation and neuronal differentiation and reduced Aβ toxin-mediated toxicity and neurodegeneration, leading to behavioral recovery in the rat AD model. ETH inhibited Aβ-mediated suppression of neurogenic and Akt/Wnt/β-catenin pathway gene expression in the hippocampus. ETH activated the PI3K·Akt and Wnt·β-catenin transduction pathways that are known to be involved in the regulation of neurogenesis. Inhibition of the PI3K·Akt and Wnt·β-catenin pathways effectively blocked the mitogenic and neurogenic effects of ETH. In silico molecular target prediction docking studies suggest that ETH interacts with Akt, Dkk-1, and GSK-3β. Our findings suggest that ETH stimulates NSC proliferation and differentiation in vitro and adult hippocampal neurogenesis via the PI3K·Akt and Wnt·β-catenin signaling.

  12. Ethosuximide Induces Hippocampal Neurogenesis and Reverses Cognitive Deficits in an Amyloid-β Toxin-induced Alzheimer Rat Model via the Phosphatidylinositol 3-Kinase (PI3K)/Akt/Wnt/β-Catenin Pathway.

    PubMed

    Tiwari, Shashi Kant; Seth, Brashket; Agarwal, Swati; Yadav, Anuradha; Karmakar, Madhumita; Gupta, Shailendra Kumar; Choubey, Vinay; Sharma, Abhay; Chaturvedi, Rajnish Kumar

    2015-11-20

    Neurogenesis involves generation of new neurons through finely tuned multistep processes, such as neural stem cell (NSC) proliferation, migration, differentiation, and integration into existing neuronal circuitry in the dentate gyrus of the hippocampus and subventricular zone. Adult hippocampal neurogenesis is involved in cognitive functions and altered in various neurodegenerative disorders, including Alzheimer disease (AD). Ethosuximide (ETH), an anticonvulsant drug is used for the treatment of epileptic seizures. However, the effects of ETH on adult hippocampal neurogenesis and the underlying cellular and molecular mechanism(s) are yet unexplored. Herein, we studied the effects of ETH on rat multipotent NSC proliferation and neuronal differentiation and adult hippocampal neurogenesis in an amyloid β (Aβ) toxin-induced rat model of AD-like phenotypes. ETH potently induced NSC proliferation and neuronal differentiation in the hippocampus-derived NSC in vitro. ETH enhanced NSC proliferation and neuronal differentiation and reduced Aβ toxin-mediated toxicity and neurodegeneration, leading to behavioral recovery in the rat AD model. ETH inhibited Aβ-mediated suppression of neurogenic and Akt/Wnt/β-catenin pathway gene expression in the hippocampus. ETH activated the PI3K·Akt and Wnt·β-catenin transduction pathways that are known to be involved in the regulation of neurogenesis. Inhibition of the PI3K·Akt and Wnt·β-catenin pathways effectively blocked the mitogenic and neurogenic effects of ETH. In silico molecular target prediction docking studies suggest that ETH interacts with Akt, Dkk-1, and GSK-3β. Our findings suggest that ETH stimulates NSC proliferation and differentiation in vitro and adult hippocampal neurogenesis via the PI3K·Akt and Wnt·β-catenin signaling. PMID:26420483

  13. PI3K in cancer: divergent roles of isoforms, modes of activation, and therapeutic targeting

    PubMed Central

    Thorpe, Lauren M.; Yuzugullu, Haluk; Zhao, Jean J.

    2015-01-01

    Preface Phosphatidylinositol 3-Kinases (PI3Ks) are critical coordinators of intracellular signaling in response to extracellular stimuli. Hyperactivation of PI3K signaling cascades is one of the most common events in human cancers. In this Review, we discuss recent advances in our knowledge of the roles of distinct PI3K isoforms in normal and oncogenic signaling, the different ways in which PI3K can be upregulated, and the current state and future potential of targeting this pathway in the clinic. PMID:25533673

  14. Analysis of PI3K pathway components in human cancers

    PubMed Central

    DARAGMEH, JAMILA; BARRIAH, WASEIM; SAAD, BASHAR; ZAID, HILAL

    2016-01-01

    Recent advances in genomics, proteomics, cell biology and biochemistry of tumors have revealed new pathways that are aberrantly activated in numerous cancer types. However, the enormous amount of data available in this field may mislead scientists in focused research. As cancer cell growth and progression is often dependent upon the phosphoinositide 3-kinase (PI3K)/AKT pathway, there has been extensive research into the proteins implicated in the PI3K pathway. Using data available in the Human Protein Atlas database, the current study investigated the expression of 25 key proteins that are known to be involved with PI3K pathway activation in a distinct group of 20 cancer types. These proteins are AKTIP, ARP1, BAD, GSK3A, GSK3B, MERTK-1, PIK3CA, PRR5, PSTPIP2, PTEN, FOX1, RHEB, RPS6KB1, TSC1, TP53, BCL2, CCND1, WFIKKN2, CREBBP, caspase-9, PTK2, EGFR, FAS, CDKN1A and XIAP. The analysis revealed pronounced expression of specific proteins in distinct cancer tissues, which may have the potential to serve as targets for treatments and provide insights into the molecular basis of cancer. PMID:27073576

  15. Structure-activity relationships of phosphoinositide 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) dual inhibitors: investigations of various 6,5-heterocycles to improve metabolic stability.

    PubMed

    Stec, Markian M; Andrews, Kristin L; Booker, Shon K; Caenepeel, Sean; Freeman, Daniel J; Jiang, Jian; Liao, Hongyu; McCarter, John; Mullady, Erin L; San Miguel, Tisha; Subramanian, Raju; Tamayo, Nuria; Wang, Ling; Yang, Kevin; Zalameda, Leeanne P; Zhang, Nancy; Hughes, Paul E; Norman, Mark H

    2011-07-28

    N-(6-(6-Chloro-5-(4-fluorophenylsulfonamido)pyridin-3-yl)benzo[d]thiazol-2-yl)acetamide (1) is a potent and efficacious inhibitor of PI3Kα and mTOR in vitro and in vivo. However, in hepatocyte and in vivo metabolism studies, 1 was found to undergo deacetylation on the 2-amino substituent of the benzothiazole. As an approach to reduce or eliminate this metabolic deacetylation, a variety of 6,5-heterocyclic analogues were examined as an alternative to the benzothiazole ring. Imidazopyridazine 10 was found to have similar in vitro potency and in vivo efficacy relative to 1, while only minimal amounts of the corresponding deacetylated metabolite of 10 were observed in hepatocytes. PMID:21714526

  16. Drosophila Spidey/Kar Regulates Oenocyte Growth via PI3-Kinase Signaling

    PubMed Central

    Cinnamon, Einat; Sawala, Annick; Tittiger, Claus; Paroush, Ze'ev

    2016-01-01

    Cell growth and proliferation depend upon many different aspects of lipid metabolism. One key signaling pathway that is utilized in many different anabolic contexts involves Phosphatidylinositide 3-kinase (PI3K) and its membrane lipid products, the Phosphatidylinositol (3,4,5)-trisphosphates. It remains unclear, however, which other branches of lipid metabolism interact with the PI3K signaling pathway. Here, we focus on specialized fat metabolizing cells in Drosophila called larval oenocytes. In the presence of dietary nutrients, oenocytes undergo PI3K-dependent cell growth and contain very few lipid droplets. In contrast, during starvation, oenocytes decrease PI3K signaling, shut down cell growth and accumulate abundant lipid droplets. We now show that PI3K in larval oenocytes, but not in fat body cells, functions to suppress lipid droplet accumulation. Several enzymes of fatty acid, triglyceride and hydrocarbon metabolism are required in oenocytes primarily for lipid droplet induction rather than for cell growth. In contrast, a very long chain fatty-acyl-CoA reductase (FarO) and a putative lipid dehydrogenase/reductase (Spidey, also known as Kar) not only promote lipid droplet induction but also inhibit oenocyte growth. In the case of Spidey/Kar, we show that the growth suppression mechanism involves inhibition of the PI3K signaling pathway upstream of Akt activity. Together, the findings in this study show how Spidey/Kar and FarO regulate the balance between the cell growth and lipid storage of larval oenocytes. PMID:27500738

  17. Drosophila Spidey/Kar Regulates Oenocyte Growth via PI3-Kinase Signaling.

    PubMed

    Cinnamon, Einat; Makki, Rami; Sawala, Annick; Wickenberg, Leah P; Blomquist, Gary J; Tittiger, Claus; Paroush, Ze'ev; Gould, Alex P

    2016-08-01

    Cell growth and proliferation depend upon many different aspects of lipid metabolism. One key signaling pathway that is utilized in many different anabolic contexts involves Phosphatidylinositide 3-kinase (PI3K) and its membrane lipid products, the Phosphatidylinositol (3,4,5)-trisphosphates. It remains unclear, however, which other branches of lipid metabolism interact with the PI3K signaling pathway. Here, we focus on specialized fat metabolizing cells in Drosophila called larval oenocytes. In the presence of dietary nutrients, oenocytes undergo PI3K-dependent cell growth and contain very few lipid droplets. In contrast, during starvation, oenocytes decrease PI3K signaling, shut down cell growth and accumulate abundant lipid droplets. We now show that PI3K in larval oenocytes, but not in fat body cells, functions to suppress lipid droplet accumulation. Several enzymes of fatty acid, triglyceride and hydrocarbon metabolism are required in oenocytes primarily for lipid droplet induction rather than for cell growth. In contrast, a very long chain fatty-acyl-CoA reductase (FarO) and a putative lipid dehydrogenase/reductase (Spidey, also known as Kar) not only promote lipid droplet induction but also inhibit oenocyte growth. In the case of Spidey/Kar, we show that the growth suppression mechanism involves inhibition of the PI3K signaling pathway upstream of Akt activity. Together, the findings in this study show how Spidey/Kar and FarO regulate the balance between the cell growth and lipid storage of larval oenocytes. PMID:27500738

  18. Targeting PI3 kinase/AKT/mTOR signaling in cancer.

    PubMed

    Sheppard, Karen; Kinross, Kathryn M; Solomon, Benjamin; Pearson, Richard B; Phillips, Wayne A

    2012-01-01

    The phosphatidylinositol 3 kinase (PI3K) pathway is one of the major pathways modulating cell growth, proliferation, metabolism, survival, and angiogenesis. Hyperactivation of this pathway is one of the most frequent occurrences in human cancer and is thus an obvious target for treatment of this disease. Currently there are 26 novel compounds targeting the PI3K pathway being assessed in more than 150 cancer-related clinical trials. Although this pathway is involved in many vital biologic functions, data emanating from these clinical trials indicate that these drugs are well tolerated. This review outlines the interaction of the PI3K pathway with other signaling cascades, highlights mechanisms involved in hyperactivation, discusses current therapeutics in cancer-related clinical trials that target this pathway, and, based on preclinical data, discusses possible leads on patient selection and combinational therapy, including targeting multiple components of the associated signaling network.

  19. PI3K – From the Bench to the Clinic and Back

    PubMed Central

    Vanhaesebroeck, Bart; Vogt, Peter K.; Rommel, Christian

    2010-01-01

    From humble beginnings over 25 years ago as a lipid kinase activity associated with certain oncoproteins, PI3K (phosphoinositide 3-kinase) has been catapulted to the forefront of drug development in cancer, immunity and thrombosis, with the first clinical trials of PI3K pathway inhibitors now in progress. Here we give a brief overview of some key discoveries in the PI3K area and their impact, and include thoughts on the current state of the field, and where it could go from here. PMID:20549473

  20. PI3K Signaling in B and T Lymphocytes: New Developments and Therapeutic Advances

    PubMed Central

    So, Lomon; Fruman, David A.

    2012-01-01

    Synopsis Activation of phosphoinositide 3-kinase (PI3K) is a shared response to engagement of diverse types of transmembrane receptors. Depending on the cell type and stimulus, PI3K activation can promote different fates including proliferation, survival, migration and differentiation. The diverse roles of PI3K signaling are well illustrated by studies of lymphocytes, the cells that mediate adaptive immunity. Genetic and pharmacological experiments have shown that PI3K activation regulates many steps in the development, activation and differentiation of both B and T cells. These findings have prompted the development of PI3K inhibitors for the treatment of autoimmunity and inflammatory diseases. However, PI3K activation has both positive and negative roles in immune system activation. Consequently, while PI3K suppression can attenuate immune responses it can also enhance inflammation, disrupt peripheral tolerance and promote autoimmunity. An exciting discovery is that a selective inhibitor of the p110δ catalytic isoform of PI3K, CAL-101, achieves impressive clinical efficacy in certain B cell malignancies. A model is emerging in which p110δ inhibition disrupts signals from the lymphoid microenvironment, leading to release of leukemia and lymphoma cells from their protective niche. These encouraging findings have given further momentum to PI3K drug development efforts in both cancer and immune diseases. PMID:22364281

  1. Genetics Home Reference: activated PI3K-delta syndrome

    MedlinePlus

    ... Health Conditions activated PI3K-delta syndrome activated PI3K-delta syndrome Enable Javascript to view the expand/collapse ... PDF Open All Close All Description Activated PI3K-delta syndrome is a disorder that impairs the immune ...

  2. Sat-Nav for T cells: Role of PI3K isoforms and lipid phosphatases in migration of T lymphocytes.

    PubMed

    Ward, Stephen G; Westwick, John; Harris, Stephanie

    2011-07-01

    Phosphoinositide 3-kinase (PI3K)-dependent signaling has been placed at the heart of conserved biochemical mechanisms that facilitate cell migration of leukocytes in response to a range of chemoattractant stimuli. This review assesses the evidence for and against PI3K-dependent mechanisms of T lymphocyte migration and whether pharmacological targeting of PI3K isoforms is likely to offer potential benefit for T cell mediated pathologies. PMID:21333676

  3. PKN3 is required for malignant prostate cell growth downstream of activated PI 3-kinase

    PubMed Central

    Leenders, Frauke; Möpert, Kristin; Schmiedeknecht, Anett; Santel, Ansgar; Czauderna, Frank; Aleku, Manuela; Penschuck, Silke; Dames, Sibylle; Sternberger, Maria; Röhl, Thomas; Wellmann, Axel; Arnold, Wolfgang; Giese, Klaus; Kaufmann, Jörg; Klippel, Anke

    2004-01-01

    Chronic activation of the phosphoinositide 3-kinase (PI3K)/PTEN signal transduction pathway contributes to metastatic cell growth, but up to now effectors mediating this response are poorly defined. By simulating chronic activation of PI3K signaling experimentally, combined with three-dimensional (3D) culture conditions and gene expression profiling, we aimed to identify novel effectors that contribute to malignant cell growth. Using this approach we identified and validated PKN3, a barely characterized protein kinase C-related molecule, as a novel effector mediating malignant cell growth downstream of activated PI3K. PKN3 is required for invasive prostate cell growth as assessed by 3D cell culture assays and in an orthotopic mouse tumor model by inducible expression of short hairpin RNA (shRNA). We demonstrate that PKN3 is regulated by PI3K at both the expression level and the catalytic activity level. Therefore, PKN3 might represent a preferred target for therapeutic intervention in cancers that lack tumor suppressor PTEN function or depend on chronic activation of PI3K. PMID:15282551

  4. PI3K is negatively regulated by PIK3IP1, a novel p110 interacting protein

    SciTech Connect

    Zhu, Zhenqi; He, Xin; Johnson, Carla; Stoops, John; Eaker, Amanda E.; Stoffer, David S.; Bell, Aaron; Zarnegar, Reza; DeFrances, Marie C. . E-mail: defrancesmc@upmc.edu

    2007-06-22

    Signaling initiated by Class Ia phosphatidylinositol-3-kinases (PI3Ks) is essential for cell proliferation and survival. We discovered a novel protein we call PI3K interacting protein 1 (PIK3IP1) that shares homology with the p85 regulatory PI3K subunit. Using a variety of in vitro and cell based assays, we demonstrate that PIK3IP1 directly binds to the p110 catalytic subunit and down modulates PI3K activity. Our studies suggest that PIK3IP1 is a new type of PI3K regulator.

  5. Colon Cancer Tumorigenesis Initiated by the H1047R Mutant PI3K

    PubMed Central

    Yueh, Alexander E.; Payne, Susan N.; Leystra, Alyssa A.; Van De Hey, Dana R.; Foley, Tyler M.; Pasch, Cheri A.; Clipson, Linda; Matkowskyj, Kristina A.; Deming, Dustin A.

    2016-01-01

    The phosphoinositide 3-kinase (PI3K) signaling pathway is critical for multiple important cellular functions, and is one of the most commonly altered pathways in human cancers. We previously developed a mouse model in which colon cancers were initiated by a dominant active PI3K p110-p85 fusion protein. In that model, well-differentiated mucinous adenocarcinomas developed within the colon and initiated through a non-canonical mechanism that is not dependent on WNT signaling. To assess the potential relevance of PI3K mutations in human cancers, we sought to determine if one of the common mutations in the human disease could also initiate similar colon cancers. Mice were generated expressing the Pik3caH1047R mutation, the analog of one of three human hotspot mutations in this gene. Mice expressing a constitutively active PI3K, as a result of this mutation, develop invasive adenocarcinomas strikingly similar to invasive adenocarcinomas found in human colon cancers. These tumors form without a polypoid intermediary and also lack nuclear CTNNB1 (β-catenin), indicating a non-canonical mechanism of tumor initiation mediated by the PI3K pathway. These cancers are sensitive to dual PI3K/mTOR inhibition indicating dependence on the PI3K pathway. The tumor tissue remaining after treatment demonstrated reduction in cellular proliferation and inhibition of PI3K signaling. PMID:26863299

  6. PIK3CA mutations can initiate pancreatic tumorigenesis and are targetable with PI3K inhibitors

    PubMed Central

    Payne, S N; Maher, M E; Tran, N H; Van De Hey, D R; Foley, T M; Yueh, A E; Leystra, A A; Pasch, C A; Jeffrey, J J; Clipson, L; Matkowskyj, K A; Deming, D A

    2015-01-01

    Aberrations in the phosphoinositide 3-kinase (PI3K) signaling pathway have a key role in the pathogenesis of numerous cancers by altering cell growth, metabolism, proliferation and apoptosis. Interest in targeting the PI3K signaling cascade continues, as new agents are being clinically evaluated. PIK3CA mutations result in a constitutively active PI3K and are present in a subset of pancreatic cancers. Here we examine mutant PIK3CA-mediated pancreatic tumorigenesis and the response of PIK3CA mutant pancreatic cancers to dual PI3K/mammalian target of rapamycin (mTOR) inhibition. Two murine models were generated expressing a constitutively active PI3K within the pancreas. An increase in acinar-to-ductal metaplasia and pancreatic intraepithelial neoplasms (PanINs) was identified. In one model these lesions were detected as early as 10 days of age. Invasive pancreatic ductal adenocarcinoma developed in these mice as early as 20 days of age. These cancers were highly sensitive to treatment with dual PI3K/mTOR inhibition. In the second model, PanINs and invasive cancer develop with a greater latency owing to a lesser degree of PI3K pathway activation in this murine model. In addition to PI3K pathway activation, increased ERK1/2 signaling is common in human pancreatic cancers. Phosphorylation of ERK1/2 was also investigated in these models. Phosphorylation of ERK1/2 is demonstrated in the pre-neoplastic lesions and invasive cancers. This activation of ERK1/2 is diminished with dual PI3K/mTOR inhibition. In summary, PIK3CA mutations can initiate pancreatic tumorigenesis and these cancers are particularly sensitive to dual PI3K/mTOR inhibition. Future studies of PI3K pathway inhibitors for patients with PIK3CA mutant pancreatic cancers are warranted. PMID:26436951

  7. Discovery of a Novel Series of Thienopyrimidine as Highly Potent and Selective PI3K Inhibitors

    PubMed Central

    2015-01-01

    Inhibition of the phosphoinositide 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling pathway provides a promising new approach for cancer therapy. Through a rational design, a novel series of thienopyrimidine was discovered as highly potent and selective PI3K inhibitors. These thienopyrimidine derivatives were demonstrated to bear nanomolar PI3Kα inhibitory potency with over 100-fold selectivity against mTOR kinase. The lead compounds 6g and 6k showed good developability profiles in cell-based proliferation and ADME assays. In this communication, their design, synthesis, structure–activity relationship, selectivity, and some developability properties are described. PMID:25893045

  8. Reactivation of AKT signaling following treatment of cancer cells with PI3K inhibitors attenuates their antitumor effects

    SciTech Connect

    Dufour, Marc; Dormond-Meuwly, Anne; Pythoud, Catherine; Demartines, Nicolas; Dormond, Olivier

    2013-08-16

    Highlights: •PI3K inhibitors inhibit AKT only transiently. •Re-activation of AKT limits the anti-cancer effect of PI3K inhibitors. •The results suggest to combine PI3K and AKT inhibitors in cancer therapy. -- Abstract: Targeting the phosphatidylinositol-3-kinase (PI3K) is a promising approach in cancer therapy. In particular, PI3K blockade leads to the inhibition of AKT, a major downstream effector responsible for the oncogenic activity of PI3K. However, we report here that small molecule inhibitors of PI3K only transiently block AKT signaling. Indeed, treatment of cancer cells with PI3K inhibitors results in a rapid inhibition of AKT phosphorylation and signaling which is followed by the reactivation of AKT signaling after 48 h as observed by Western blot. Reactivation of AKT signaling occurs despite effective inhibition of PI3K activity by PI3K inhibitors. In addition, wortmannin, a broad range PI3K inhibitor, did not block AKT reactivation suggesting that AKT signals independently of PI3K. In a therapeutical perspective, combining AKT and PI3K inhibitors exhibit stronger anti-proliferative and pro-apoptotic effects compared to AKT or PI3K inhibitors alone. Similarly, in a tumor xenograft mouse model, concomitant PI3K and AKT blockade results in stronger anti-cancer activity compared with either blockade alone. This study shows that PI3K inhibitors only transiently inhibit AKT which limits their antitumor activities. It also provides the proof of concept to combine PI3K inhibitors with AKT inhibitors in cancer therapy.

  9. PI3-kinase activation is critical for host barrier permissiveness to Listeria monocytogenes

    PubMed Central

    Gessain, Grégoire; Tsai, Yu-Huan; Travier, Laetitia; Bonazzi, Matteo; Grayo, Solène; Cossart, Pascale; Charlier, Caroline; Disson, Olivier

    2015-01-01

    Invasion of nonphagocytic cells, a critical property of Listeria monocytogenes (Lm) that enables it to cross host barriers, is mediated by the interaction of two bacterial surface proteins, InlA and InlB, with their respective receptors E-cadherin and c-Met. Although InlA–E-cadherin interaction is necessary and sufficient for Lm crossing of the intestinal barrier, both InlA and InlB are required for Lm crossing of the placental barrier. The mechanisms underlying these differences are unknown. Phosphoinositide 3-kinase (PI3-K) is involved in both InlA- and InlB-dependent pathways. Indeed, InlA-dependent entry requires PI3-K activity but does not activate it, whereas InlB–c-Met interaction activates PI3-K. We show that Lm intestinal target cells exhibit a constitutive PI3-K activity, rendering InlB dispensable for InlA-dependent Lm intestinal barrier crossing. In contrast, the placental barrier does not exhibit constitutive PI3-K activity, making InlB necessary for InlA-dependent Lm placental invasion. Here, we provide the molecular explanation for the respective contributions of InlA and InlB to Lm host barrier invasion, and reveal the critical role of InlB in rendering cells permissive to InlA-mediated invasion. This study shows that PI3-K activity is critical to host barrier permissiveness to microbes, and that pathogens exploit both similarities and differences of host barriers to disseminate. PMID:25624443

  10. Status of PI3K/Akt/mTOR pathway inhibitors in lymphoma.

    PubMed

    Westin, Jason R

    2014-10-01

    The phosphatidylinositol-3-kinase (PI3K) pathway is well known to regulate a wide variety of essential cellular functions, including glucose metabolism, translational regulation of protein synthesis, cell proliferation, apoptosis, and survival. Aberrations in the PI3K pathway are among the most frequently observed in cancer, and include amplifications, rearrangements, mutations, and loss of regulators. As a net result of these anomalies, the PI3K pathway is activated in many malignancies, including in Hodgkin and non-Hodgkin lymphomas, and yields a competitive growth and survival advantage, increased metastatic ability, and resistance to conventional therapy. Numerous inhibitors targeting various nodes in the PI3K pathway are undergoing clinical development, and their current status in lymphoma will be the focus of this review.

  11. Dual PI-3 kinase/mTOR inhibition impairs autophagy flux and induces cell death independent of apoptosis and necroptosis.

    PubMed

    Button, Robert W; Vincent, Joseph H; Strang, Conor J; Luo, Shouqing

    2016-02-01

    The PI-3 kinase (PI-3K)/mTOR pathway is critical for cell growth and proliferation. Strategies of antagonising this signaling have proven to be detrimental to cell survival. This observation, coupled with the fact many tumours show enhanced growth signaling, has caused dual inhibitors of PI-3K and mTOR to be implicated in cancer treatment, and have thus been studied across various tumour models. Since PI-3K (class-I)/mTOR pathway negatively regulates autophagy, dual inhibitors of PI-3K/mTOR are currently believed to be autophagy activators. However, our present data show that the dual PI-3K/mTOR inhibition (DKI) potently suppresses autophagic flux. We further confirm that inhibition of Vps34/PI3KC3, the class-III PI-3K, causes the blockade to autophagosome-lysosome fusion. Our data suggest that DKI induces cell death independently of apoptosis and necroptosis, whereas autophagy perturbation by DKI may contribute to cell death. Given that autophagy is critical in cellular homeostasis, our study not only clarifies the role of a dual PI-3K/mTOR inhibitor in autophagy, but also suggests that its autophagy inhibition needs to be considered if such an agent is used in cancer chemotherapy.

  12. Dual PI-3 kinase/mTOR inhibition impairs autophagy flux and induces cell death independent of apoptosis and necroptosis

    PubMed Central

    Button, Robert W.; Vincent, Joseph H.; Strang, Conor J.; Luo, Shouqing

    2016-01-01

    The PI-3 kinase (PI-3K)/mTOR pathway is critical for cell growth and proliferation. Strategies of antagonising this signaling have proven to be detrimental to cell survival. This observation, coupled with the fact many tumours show enhanced growth signaling, has caused dual inhibitors of PI-3K and mTOR to be implicated in cancer treatment, and have thus been studied across various tumour models. Since PI-3K (class-I)/mTOR pathway negatively regulates autophagy, dual inhibitors of PI-3K/mTOR are currently believed to be autophagy activators. However, our present data show that the dual PI-3K/mTOR inhibition (DKI) potently suppresses autophagic flux. We further confirm that inhibition of Vps34/PI3KC3, the class-III PI-3K, causes the blockade to autophagosome-lysosome fusion. Our data suggest that DKI induces cell death independently of apoptosis and necroptosis, whereas autophagy perturbation by DKI may contribute to cell death. Given that autophagy is critical in cellular homeostasis, our study not only clarifies the role of a dual PI-3K/mTOR inhibitor in autophagy, but also suggests that its autophagy inhibition needs to be considered if such an agent is used in cancer chemotherapy. PMID:26814436

  13. Abrogating endocrine resistance by targeting ERα and PI3K in breast cancer

    PubMed Central

    Fox, Emily M.; Arteaga, Carlos L.; Miller, Todd W.

    2012-01-01

    Antiestrogen therapies targeting estrogen receptor α (ER) signaling are a mainstay for patients with ER+ breast cancer. While many cancers exhibit resistance to antiestrogen therapies, a large body of clinical and experimental evidence indicates that hyperactivation of the phosphatidylinositol 3-kinase (PI3K) pathway promotes antiestrogen resistance. In addition, continued ligand-independent ER signaling in the setting of estrogen deprivation may contribute to resistance to endocrine therapy. PI3K activates several proteins which promote cell cycle progression and survival. In ER+ breast cancer cells, PI3K promotes ligand-dependent and -independent ER transcriptional activity. Models of antiestrogen-resistant breast cancer often remain sensitive to estrogen stimulation and PI3K inhibition, suggesting that clinical trials with combinations of drugs targeting both the PI3K and ER pathways are warranted. Herein, we review recent findings on the roles of PI3K and ER in antiestrogen resistance, and clinical trials testing drug combinations which target both pathways. We also discuss the need for clinical investigation of ER downregulators in combination with PI3K inhibitors. PMID:23087906

  14. Differential regulation of protrusion and polarity by PI(3)K during neutrophil motility in live zebrafish

    PubMed Central

    Yoo, Sa Kan; Deng, Qing; Cavnar, Peter J.; Wu, Yi I.; Hahn, Klaus M.; Huttenlocher, Anna

    2010-01-01

    Summary Cell polarity is crucial for directed migration. Here we show that phosphoinositide 3-kinase (PI(3)K) mediates neutrophil migration in vivo by differentially regulating cell protrusion and polarity. The dynamics of PI(3)K products PI(3,4,5)P3-PI(3,4)P2 during neutrophil migration were visualized in living zebrafish, revealing that PI(3)K activation at the leading edge is critical for neutrophil motility in intact tissues. A genetically encoded photoactivatable Rac was used to demonstrate that localized activation of Rac is sufficient to direct migration with precise temporal and spatial control in vivo. Similar stimulation of PI(3)K-inhibited cells did not direct migration. Localized Rac activation rescued membrane protrusion but not anteroposterior polarization of F-actin dynamics of PI(3)K-inhibited cells. Uncoupling Rac-mediated protrusion and polarization suggests a paradigm of two-tiered PI(3)K-mediated regulation of cell motility. This work provides new insight into how cell signaling at the front and back of the cell is coordinated during polarized cell migration in intact tissues within a multicellular organism. PMID:20159593

  15. PI3 kinase is involved in cocaine behavioral sensitization and its reversal with brain area specificity

    SciTech Connect

    Zhang Xiuwu . E-mail: xwzhang@duke.edu; Mi Jing; Wetsel, William C.; Davidson, Colin; Xiong Xieying; Chen Qiang; Ellinwood, Everett H.; Lee, Tong H.

    2006-02-24

    Phosphatidylinositol 3-kinase (PI3K) is an important signaling molecule involved in cell differentiation, proliferation, survival, and phagocytosis, and may participate in various brain functions. To determine whether it is also involved in cocaine sensitization, we measured the p85{alpha}/p110 PI3K activity in the nuclear accumbens (NAc) shell, NAc core, and prefrontal cortex (PFC) following establishment of cocaine sensitization and its subsequent reversal. Naive rats were rank-ordered and split into either daily cocaine or saline pretreatment group based on their locomotor responses to an acute cocaine injection (7.5 mg/kg, i.p.). These two groups were then injected with cocaine (40 mg/kg, s.c.) or saline for 4 consecutive days followed by 9-day withdrawal. Cocaine sensitization was subsequently reversed by 5 daily injections of the D{sub 1}/D{sub 2} agonist pergolide (0.1 mg/kg, s.c.) in combination with the 5-HT{sub 3} antagonist ondansetron (0.2 mg/kg, s.c., 3.5 h after pergolide injection). After another 9-day withdrawal, behavioral cocaine sensitization and its reversal were confirmed with an acute cocaine challenge (7.5 mg/kg, i.p.), and animals were sacrificed the next day for measurement of p85{alpha}/p110 PI3K activity. Cocaine-sensitized animals exhibited increased PI3K activity in the NAc shell, and this increase was reversed by combined pergolide/ondansetron treatment, which also reversed behavioral sensitization. In the NAc core and PFC, cocaine sensitization decreased and increased the PI3K activity, respectively. These changes, in contrast to that in the NAc shell, were not normalized following the reversal of cocaine-sensitization. Interestingly, daily injections of pergolide alone in saline-pretreated animals induced PI3K changes that were similar to the cocaine sensitization-associated changes in the NAc core and PFC but not the NAc shell; furthermore, these changes in saline-pretreated animals were prevented by ondansetron given 3.5 h after

  16. The PI3K/AKT Pathway as a Target for Cancer Treatment.

    PubMed

    Mayer, Ingrid A; Arteaga, Carlos L

    2016-01-01

    Anticancer targeted therapies are designed to exploit a particular vulnerability in the tumor, which in most cases results from its dependence on an oncogene and/or loss of a tumor suppressor. Genes in the phosphoinositide 3-kinase (PI3K)/AKT pathway are the most frequently altered in human cancers. Aberrant activation of this pathway, as a result of these somatic alterations, is associated with cellular transformation, tumorigenesis, cancer progression, and drug resistance. Several drugs targeting PI3K/ATK are currently in clinical trials, alone or in combination, in both solid tumors and hematologic malignancies. These drugs are the focus of this review.

  17. PI3K isoform-selective inhibitors: next-generation targeted cancer therapies

    PubMed Central

    Wang, Xiang; Ding, Jian; Meng, Ling-hua

    2015-01-01

    The pivotal roles of phosphatidylinositol 3-kinases (PI3Ks) in human cancers have inspired active development of small molecules to inhibit these lipid kinases. However, the first-generation pan-PI3K and dual-PI3K/mTOR inhibitors have encountered problems in clinical trials, with limited efficacies as a monotherapeutic agent as well as a relatively high rate of side effects. It is increasingly recognized that different PI3K isoforms play non-redundant roles in particular tumor types, which has prompted the development of isoform-selective inhibitors for pre-selected patients with the aim for improving efficacy while decreasing undesirable side effects. The success of PI3K isoform-selective inhibitors is represented by CAL101 (Idelalisib), a first-in-class PI3Kδ-selective small-molecule inhibitor that has been approved by the FDA for the treatment of chronic lymphocytic leukemia, indolent B-cell non-Hodgkin's lymphoma and relapsed small lymphocytic lymphoma. Inhibitors targeting other PI3K isoforms are also being extensively developed. This review focuses on the recent progress in development of PI3K isoform-selective inhibitors for cancer therapy. A deeper understanding of the action modes of novel PI3K isoform-selective inhibitors will provide valuable information to further validate the concept of targeting specific PI3K isoforms, while the identification of biomarkers to stratify patients who are likely to benefit from the therapy will be essential for the success of these agents. PMID:26364801

  18. PI3 Kinase signals BCR dependent mature B cell survival

    PubMed Central

    Srinivasan, Lakshmi; Sasaki, Yoshiteru; Calado, Dinis Pedro; Zhang, Baochun; Paik, Ji Hye; DePinho, Ronald A.; Kutok, Jeffrey L.; Kearney, John F.; Otipoby, Kevin L.; Rajewsky, Klaus

    2009-01-01

    Summary Previous work has shown that mature B cells depend upon survival signals delivered to the cells by their antigen receptor (BCR). To identify the molecular nature of this survival signal, we have developed a genetic approach in which ablation of the BCR is combined with the activation of specific, BCR dependent signaling cascades in mature B cells in vivo. Using this system, we provide evidence that the survival of BCR deficient mature B cells can be rescued by a single signaling pathway downstream of the BCR, namely PI3K signaling, with the FOXO1 transcription factor playing a central role. PMID:19879843

  19. Regulation of Mammalian Autophagy by Class II and III PI 3-Kinases through PI3P Synthesis

    PubMed Central

    Devereaux, Kelly; Ogasawara, Yuta; Zhou, Xiang; Wang, Fan; Yamamoto, Akitsugu; De Camilli, Pietro; Di Paolo, Gilbert

    2013-01-01

    Synthesis of phosphatidylinositol-3-phosphate (PI3P) by Vps34, a class III phosphatidylinositol 3-kinase (PI3K), is critical for the initial steps of autophagosome (AP) biogenesis. Although Vps34 is the sole source of PI3P in budding yeast, mammalian cells can produce PI3P through alternate pathways, including direct synthesis by the class II PI3Ks; however, the physiological relevance of these alternate pathways in the context of autophagy is unknown. Here we generated Vps34 knockout mouse embryonic fibroblasts (MEFs) and using a higher affinity 4x-FYVE finger PI3P-binding probe found a Vps34-independent pool of PI3P accounting for ~35% of the total amount of this lipid species by biochemical analysis. Importantly, WIPI-1, an autophagy-relevant PI3P probe, still formed some puncta upon starvation-induced autophagy in Vps34 knockout MEFs. Additional characterization of autophagy by electron microscopy as well as protein degradation assays showed that while Vps34 is important for starvation-induced autophagy there is a significant component of functional autophagy occurring in the absence of Vps34. Given these findings, class II PI3Ks (α and β isoforms) were examined as potential positive regulators of autophagy. Depletion of class II PI3Ks reduced recruitment of WIPI-1 and LC3 to AP nucleation sites and caused an accumulation of the autophagy substrate, p62, which was exacerbated upon the concomitant ablation of Vps34. Our studies indicate that while Vps34 is the main PI3P source during autophagy, class II PI3Ks also significantly contribute to PI3P generation and regulate AP biogenesis. PMID:24098492

  20. RhoC promotes human melanoma invasion in a PI3K/Akt-dependent pathway.

    PubMed

    Ruth, Mariah C; Xu, Yisheng; Maxwell, Ian H; Ahn, Natalie G; Norris, David A; Shellman, Yiqun G

    2006-04-01

    Overexpression of the small GTPase, RhoC, in various human cancers has been correlated with high metastatic ability and poor prognosis. Rho-kinase (ROCK) is an important effector of Rho GTPases. The oncogenic serine/threonine kinase Akt (also known as PKB) is a downstream effector of phosphatidylinositol-3 kinase (PI3K). Akt activation contributes to the neoplastic phenotype by promoting cell cycle progression, increasing antiapoptotic functions, and enhancing tumor cell invasion. Rho signaling via ROCK has been previously shown either to activate or to downregulate PI3K/Akt. Using a human radial growth phase melanoma cell line, WM35, we have established stable transfectants that overexpress RhoC (called WM35RhoC). We found that overexpression of RhoC increased phosphorylated-Akt (Ser473/474/472, pAkt) expression and promoted cell invasion. Inhibition of RhoC with C3 transferase downregulated pAkt expression and decreased cell invasion in these cells. In addition, inhibition of PI3K, Akt, or ROCK partially decreased invasion. Further, inhibition of PI3K but not ROCK decreased the pAkt level. These results suggest that RhoC promotes invasion in part via activation of a PI3K/Akt pathway, in a manner independent of ROCK signaling. We propose that RhoC promotes melanoma progression via separate mechanisms that regulate the PI3K/Akt pathway and the ROCK signaling pathway.

  1. PI-103 and Quercetin Attenuate PI3K-AKT Signaling Pathway in T- Cell Lymphoma Exposed to Hydrogen Peroxide.

    PubMed

    Maurya, Akhilendra Kumar; Vinayak, Manjula

    2016-01-01

    Phosphatidylinositol 3 kinase-protein kinase B (PI3K-AKT) pathway has been considered as major drug target site due to its frequent activation in cancer. AKT regulates the activity of various targets to promote tumorigenesis and metastasis. Accumulation of reactive oxygen species (ROS) has been linked to oxidative stress and regulation of signaling pathways for metabolic adaptation of tumor microenvironment. Hydrogen peroxide (H2O2) in this context is used as ROS source for oxidative stress preconditioning. Antioxidants are commonly considered to be beneficial to reduce detrimental effects of ROS and are recommended as dietary supplements. Quercetin, a ubiquitous bioactive flavonoid is a dietary component which has attracted much of interest due to its potential health-promoting effects. Present study is aimed to analyze PI3K-AKT signaling pathway in H2O2 exposed Dalton's lymphoma ascite (DLA) cells. Further, regulation of PI3K-AKT pathway by quercetin as well as PI-103, an inhibitor of PI3K was analyzed. Exposure of H2O2 (1mM H2O2 for 30min) to DLA cells caused ROS accumulation and resulted in increased phosphorylation of PI3K and downstream proteins PDK1 and AKT (Ser-473 and Thr-308), cell survival factors BAD and ERK1/2, as well as TNFR1. However, level of tumor suppressor PTEN was declined. Both PI-103 & quercetin suppressed the enhanced level of ROS and significantly down-regulated phosphorylation of AKT, PDK1, BAD and level of TNFR1 as well as increased the level of PTEN in H2O2 induced lymphoma cells. The overall result suggests that quercetin and PI3K inhibitor PI-103 attenuate PI3K-AKT pathway in a similar mechanism. PMID:27494022

  2. PI3K-Akt pathway: its functions and alterations in human cancer.

    PubMed

    Osaki, M; Oshimura, M; Ito, H

    2004-11-01

    Phosphatidylinositol-3-kinase (PI3K) is a lipid kinase and generates phosphatidylinositol-3,4,5-trisphosphate (PI(3, 4, 5)P3). PI(3, 4, 5)P3 is a second messenger essential for the translocation of Akt to the plasma membrane where it is phosphorylated and activated by phosphoinositide-dependent kinase (PDK) 1 and PDK2. Activation of Akt plays a pivotal role in fundamental cellular functions such as cell proliferation and survival by phosphorylating a variety of substrates. In recent years, it has been reported that alterations to the PI3K-Akt signaling pathway are frequent in human cancer. Constitutive activation of the PI3K-Akt pathway occurs due to amplification of the PIK3C gene encoding PI3K or the Akt gene, or as a result of mutations in components of the pathway, for example PTEN (phosphatase and tensin homologue deleted on chromosome 10), which inhibit the activation of Akt. Several small molecules designed to specifically target PI3K-Akt have been developed, and induced cell cycle arrest or apoptosis in human cancer cells in vitro and in vivo . Moreover, the combination of an inhibitor with various cytotoxic agents enhances the anti-tumor efficacy. Therefore, specific inhibition of the activation of Akt may be a valid approach to treating human malignancies and overcoming the resistance of cancer cells to radiation or chemotherapy. PMID:15505410

  3. Class I PI3K in oncogenic cellular transformation

    PubMed Central

    Zhao, Li; Vogt, Peter K.

    2009-01-01

    Class I phosphoinositide 3-kinase (PI3K) is a dimeric enzyme, consisting of a catalytic and a regulatory subunit. The catalytic subunit occurs in four isoforms designated as p110α, p110β, p110γ and p110δ. These combine with several regulatory subunits; for p110α, β and δ the standard regulatory subunit is p85, for p110γ it is p101. PI3Ks play important roles in human cancer. PIK3CA, the gene encoding p110α, is mutated frequently in common cancers, including carcinoma of the breast, prostate, colon and endometrium. Eighty percent of these mutations are represented by one of three amino acid substitutions in the helical or kinase domains of the enzyme. The mutant p110α shows a gain of function in enzymatic and signaling activity and is oncogenic in cell culture and in animal model systems. Structural and genetic data suggest that the mutations affect regulatory inter- and intramolecular interactions and support the conclusion that there are at least two molecular mechanisms for the gain-of-function in p110α. One of these mechanisms operates largely independently of binding to p85, the other abolishes the requirement for an interaction with Ras. The non-alpha isoforms of p110 do not show cancer-specific mutations. However, they are often differentially expressed in cancer and, in contrast to p110α, wild-type non-alpha isoforms of p110 are oncogenic when overexpressed in cell culture. The isoforms of p110 have become promising drug targets. Isoform-selective inhibitors have been identified. Inhibitors that target exclusively the cancer-specific mutants of p110α constitute an important goal and challenge for current drug development. PMID:18794883

  4. Apelin-13 promotes cardiomyocyte hypertrophy via PI3K-Akt-ERK1/2-p70S6K and PI3K-induced autophagy.

    PubMed

    Xie, Feng; Liu, Wei; Feng, Fen; Li, Xin; He, Lu; Lv, Deguan; Qin, Xuping; Li, Lifang; Li, Lanfang; Chen, Linxi

    2015-12-01

    Apelin is highly expressed in rat left ventricular hypertrophy Sprague Dawley rat models, and it plays a crucial role in the cardiovascular system. The aim this study was to clarify whether apelin-13 promotes hypertrophy in H9c2 rat cardiomyocytes and to investigate its underlying mechanism. The cardiomyocyte hypertrophy was observed by measuring the diameter, volume, and protein content of H9c2 cells. The activation of autophagy was evaluated by observing the morphology of autophagosomes by transmission electron microscopy, observing the subcellular localization of LC3 by light microscopy, and detecting the membrane-associated form of LC3 by western blot analysis. The phosphatidylinositol 3-kinase (PI3K) signaling pathway was identified and the proteins expression was detected using western blot analysis. The results revealed that apelin-13 increased the diameter, volume, and protein content of H9c2 cells and promoted the phosphorylation of PI3K, Akt, ERK1/2, and p70S6K. Apelin-13 activated the PI3K-Akt-ERK1/2-p70S6K pathway. PI3K inhibitor LY294002, Akt inhibitor 1701-1, ERK1/2 inhibitor PD98059 attenuated the increase of the cell diameter, volume, protein content induced by apelin-13. Apelin-13 increased the autophagosomes and up-regulated the expressions of beclin 1 and LC3-II/I both transiently and stably. The autophagy inhibitor 3MA ameliorated the increase of cell diameter, volume, and protein content that were induced by apelin-13. These results suggested that apelin-13 promotes H9c2 rat cardiomyocyte hypertrophy via PI3K-Akt-ERK1/2-p70S6K and PI3K-induced autophagy. PMID:26607438

  5. Emerging concepts for PI3K/mTOR inhibition as a potential treatment for osteosarcoma.

    PubMed

    Bishop, Michael W; Janeway, Katherine A

    2016-01-01

    Patients with metastatic and recurrent osteosarcoma fare poorly, and new therapeutic strategies are needed to improve survival. Several recent complementary genomic and pathway analyses of both murine and human osteosarcoma have revealed common aberrations of the phosphoinositide 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) pathway in osteosarcoma. Preclinical data demonstrate that inhibition of PI3K and mTOR with either a combination of single agents or dual inhibiting compounds can decrease cell proliferation and induce cell cycle arrest and apoptosis. With a lack of available clinical agents active in osteosarcoma, PI3K/mTOR inhibition represents a potential vulnerability in osteosarcoma that warrants clinical investigation. PMID:27441088

  6. Eupatilin inhibits EGF-induced JB6 cell transformation by targeting PI3K.

    PubMed

    Li, Feng; Tao, Ya; Qiao, Yan; Li, Ke; Jiang, Yanan; Cao, Chang; Ren, Shuxin; Chang, Xiaobin; Wang, Xiaona; Wang, Yanhong; Xie, Yifei; Dong, Ziming; Zhao, Jimin; Liu, Kangdong

    2016-09-01

    Phosphatidylinositol 3-kinases (PI3Ks) are lipid kinases that play fundamental roles in regulation of multiple signaling pathways, including cell proliferation, survival and cell cycle. Increasing evidence has shown that abnormal activation of PI3K pathway contributes to tumorigenesis and progression of various malignant tumors. Therefore, it is an attractive target of chemoprevention and chemotherapy. Eupatilin, a natural flavone compound extracted from Artemisia vulgaris, has antitumor and anti-inflammation efficacy. However, the direct target(s) of eupatilin in cancer chemoprevention are still elusive. In the present study, we reported eupatilin suppressed JB6 cell proliferation and its EGF-induced colony formation. Eupatilin attenuated phosphorylation of PI3K downstream signaling molecules. Downregulation of cyclin D1 expression and arresting in G1 phase were induced through eupatilin treatment. Furthermore, we found it could bind to the p110α, a catalytic subunit of PI3K, by computational docking methods. Pull down assay outcomes also verified the binding of eupatilin with PI3K. Taken together, our results suggest that epatilin is a potential chemopreventive agent in inhibition of skin cell transformation by targeting PI3K. PMID:27573489

  7. Inositol polyphosphate multikinase is a physiologic PI3-kinase that activates Akt/PKB.

    PubMed

    Maag, David; Maxwell, Micah J; Hardesty, Douglas A; Boucher, Katie L; Choudhari, Namrata; Hanno, Adam G; Ma, Jenny F; Snowman, Adele S; Pietropaoli, Joseph W; Xu, Risheng; Storm, Phillip B; Saiardi, Adolfo; Snyder, Solomon H; Resnick, Adam C

    2011-01-25

    The second messenger phosphatidylinositol (3,4,5)-trisphosphate (PIP(3)), formed by the p110 family of PI3-kinases, promotes cellular growth, proliferation, and survival, in large part by activating the protein kinase Akt/PKB. We show that inositol polyphosphate multikinase (IPMK) physiologically generates PIP(3) as well as water soluble inositol phosphates. IPMK deletion reduces growth factor-elicited Akt signaling and cell proliferation caused uniquely by loss of its PI3-kinase activity. Inhibition of p110 PI3-kinases by wortmannin prevents IPMK phosphorylation and activation. Thus, growth factor stimulation of Akt signaling involves PIP(3) generation through the sequential activations of the p110 PI3-kinases and IPMK. As inositol phosphates inhibit Akt signaling, IPMK appears to act as a molecular switch, inhibiting or stimulating Akt via its inositol phosphate kinase or PI3-kinase activities, respectively. Drugs regulating IPMK may have therapeutic relevance in influencing cell proliferation.

  8. The Role of PI3K/Akt/mTOR Signaling in Gastric Carcinoma

    PubMed Central

    Matsuoka, Tasuku; Yashiro, Masakazu

    2014-01-01

    The phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway is one of the key signaling pathways induced by various receptor-tyrosine kinases. Accumulating evidence shows that this pathway is an important promoter of cell growth, metabolism, survival, metastasis, and resistance to chemotherapy. Genetic alterations in the PI3K/Akt/mTOR pathway in gastric carcinoma have often been demonstrated. Many kinds of molecular targeting therapies are currently undergoing clinical testing in patients with solid tumors. However, with the exception of the ErbB2-targeting antibody, targeting agents, including PI3K/Akt/mTOR inhibitors, have not been approved for treatment of patients with gastric carcinoma. This review summarizes the current knowledge on PI3K/Akt/mTOR signaling in the pathogenesis of gastric carcinoma and the possible therapeutic targets for gastric carcinoma. Improved knowledge of the PI3K/Akt/mTOR pathway in gastric carcinoma will be useful in understanding the mechanisms of tumor development and for identifying ideal targets of anticancer therapy for gastric carcinoma. PMID:25003395

  9. Fangchinoline targets PI3K and suppresses PI3K/AKT signaling pathway in SGC7901 cells

    PubMed Central

    TIAN, FENG; DING, DING; LI, DANDAN

    2015-01-01

    Fangchinoline, an important compound in Stephania tetrandra S. Moore, as a novel antitumor agent, has been implicated in several types of cancers cells except gastric cancer. To investigate whether fangchinoline affects gastric cancer cells, we detected the signaling pathway by which fangchinoline plays a role in different human gastric cancer cells lines. We found that fangchinoline effectively suppressed proliferation and invasion of SGC7901 cell lines, but not MKN45 cell lines by inhibiting the expression of PI3K and its downstream pathway. All of the Akt/MMP2/MMP9 pathway, Akt/Bad pathway, and Akt/Gsk3β/CDK2 pathway could be inhibited by fangchinoline through inhibition of PI3K. Taken together, these results suggest that fangchinoline targets PI3K in tumor cells that express PI3K abundantly and inhibits the growth and invasive ability of the tumor cells. PMID:25872479

  10. Fangchinoline targets PI3K and suppresses PI3K/AKT signaling pathway in SGC7901 cells.

    PubMed

    Tian, Feng; Ding, Ding; Li, Dandan

    2015-01-01

    Fangchinoline, an important compound in Stephania tetrandra S. Moore, as a novel antitumor agent, has been implicated in several types of cancers cells except gastric cancer. To investigate whether fangchinoline affects gastric cancer cells, we detected the signaling pathway by which fangchinoline plays a role in different human gastric cancer cells lines. We found that fangchinoline effectively suppressed proliferation and invasion of SGC7901 cell lines, but not MKN45 cell lines by inhibiting the expression of PI3K and its downstream pathway. All of the Akt/MMP2/MMP9 pathway, Akt/Bad pathway, and Akt/Gsk3β/CDK2 pathway could be inhibited by fangchinoline through inhibition of PI3K. Taken together, these results suggest that fangchinoline targets PI3K in tumor cells that express PI3K abundantly and inhibits the growth and invasive ability of the tumor cells. PMID:25872479

  11. Nuclear PI3K signaling in cell growth and tumorigenesis

    PubMed Central

    Davis, William J.; Lehmann, Peter Z.; Li, Weimin

    2015-01-01

    The PI3K/Akt signaling pathway is a major driving force in a variety of cellular functions. Dysregulation of this pathway has been implicated in many human diseases including cancer. While the activity of the cytoplasmic PI3K/Akt pathway has been extensively studied, the functions of these molecules and their effector proteins within the nucleus are poorly understood. Harboring key cellular processes such as DNA replication and repair as well as nascent messenger RNA transcription, the nucleus provides a unique compartmental environment for protein–protein and protein–DNA/RNA interactions required for cell survival, growth, and proliferation. Here we summarize recent advances made toward elucidating the nuclear PI3K/Akt signaling cascade and its key components within the nucleus as they pertain to cell growth and tumorigenesis. This review covers the spatial and temporal localization of the major nuclear kinases having PI3K activities and the counteracting phosphatases as well as the role of nuclear PI3K/Akt signaling in mRNA processing and exportation, DNA replication and repair, ribosome biogenesis, cell survival, and tumorigenesis. PMID:25918701

  12. Conjugation of SUMO to p85 leads to a novel mechanism of PI3K regulation.

    PubMed

    de la Cruz-Herrera, C F; Baz-Martínez, M; Lang, V; El Motiam, A; Barbazán, J; Couceiro, R; Abal, M; Vidal, A; Esteban, M; Muñoz-Fontela, C; Nieto, A; Rodríguez, M S; Collado, M; Rivas, C

    2016-06-01

    Class IA phosphatidylinositol 3-kinases (PI3Ks) are composed of p110 catalytic and p85 regulatory subunits. How regulatory subunits modulate PI3K activity remains only partially understood. Here we identified SUMO (small ubiquitin-related modifier) as a new player modulating this regulation. We demonstrate that both p85β and p85α are conjugated to SUMO1 and SUMO2. We identified two lysine residues located at the inter-SH2 domain on p85β, a critical region required for inhibition of p110, as being required for SUMO conjugation. A SUMOylation-defective mutant p85β shows higher activation of the PI3K pathway, and increased cell migration and transformation. Moreover, the cancer-related KS459del mutant in p85α was less efficiently SUMOylated compared with the wild-type protein. Finally, our results show that SUMO modulates p85 tyrosine phosphorylation, a modification correlating with PI3K pathway activation. Thus, SUMO reduces the levels of tyrosine-phosphorylated-p85 while loss of SUMOylation results in increased tyrosine phosphorylation of p85. In summary, we identify SUMO as a new important player in the regulation of the PI3K pathway through modulation of p85.

  13. Inhibition of the PI3 kinase cascade in corticolimbic circuit: temporal and differential effects on contextual fear and extinction.

    PubMed

    Kritman, Milly; Maroun, Mouna

    2013-05-01

    We studied the role of PI3K cascade in the basolateral amygdala (BLA) and the infralimbic region of the medial prefrontal cortex (IL-mPFC), in contextual fear learning and extinction in the rat. To that end, we micro-infused the phosphoinositide-3-kinase (PIK3) inhibitor LY294002 into either the mPFC or the BLA. Infusion of LY294002 into the BLA following fear conditioning was associated with enhanced freezing levels and impaired extinction in the subsequent sessions. Similarly, inhibition of PI3K in the BLA before the retrieval of fear memory was associated with impaired retrieval of the fear memory, which was expressed as reduced freezing levels that persisted over 2 d. In the IL-mPFC, only consolidation of fear extinction was impaired: micro-infusion of PI3K inhibitor following the retrieval of fear was associated with impaired extinction on the following days. These results indicate differences in the temporal parameters of the effects of PI3K inhibition in the IL-mPFC and in the BLA, which suggest differential involvement of these structures in long-term fear and in extinction of fear memory. Our findings provide additional evidence for the critical roles played by PI3K in intact formation of fear memory and in its extinction and add new evidence for a role of PI3K in consolidation of memory of extinction. Better understanding of the differential involvement of the PI3K cascade during acquisition and extinction of fear conditioning in the mPFC-amygdala circuit could potentially contribute to the understanding and treatment of anxiety disorders.

  14. Regulation of PI-3-Kinase and Akt Signaling in T Lymphocytes and Other Cells by TNFR Family Molecules

    PubMed Central

    So, Takanori; Croft, Michael

    2013-01-01

    Activation of phosphoinositide 3-kinase (PI3K) and Akt (protein kinase B) is a common response triggered by a range of membrane-bound receptors on many cell types. In T lymphocytes, the PI3K-Akt pathway promotes clonal expansion, differentiation, and survival of effector cells and suppresses the generation of regulatory T cells. PI3K activation is tightly controlled by signals through the T cell receptor (TCR) and the co-stimulatory receptor CD28, however sustained and periodic signals from additional co-receptors are now being recognized as critical contributors to the activation of this pathway. Accumulating evidence suggests that many members of the Tumor Necrosis Factor receptor (TNFR) superfamily, TNFR2 (TNFRSF1B), OX40 (TNFRSF4), 4-1BB (TNFRSF9), HVEM (TNFRSF14), and DR3 (TNFRSF25), that are constitutive or inducible on T cells, can directly or indirectly promote activity in the PI3K-Akt pathway. We discuss recent data which suggests that ligation of one TNFR family molecule organizes a signalosome, via TNFR-associated factor (TRAF) adapter proteins in T cell membrane lipid microdomains, that results in the subsequent accumulation of highly concentrated depots of PI3K and Akt in close proximity to TCR signaling units. We propose this may be a generalizable mechanism applicable to other TNFR family molecules that will result in a quantitative contribution of these signalosomes to enhancing and sustaining PI3K and Akt activation triggered by the TCR. We also review data that other TNFR molecules, such as CD40 (TNFRSF5), RANK (TNFRSF11A), FN14 (TNFRSF12A), TACI (TNFRSF13B), BAFFR (TNFRSF13C), and NGFR (TNFRSF16), contribute to the activation of this pathway in diverse cell types through a similar ability to recruit PI3K or Akt into their signaling complexes. PMID:23760533

  15. Distinct roles of class IA PI3K isoforms in primary and immortalised macrophages.

    PubMed

    Papakonstanti, Evangelia A; Zwaenepoel, Olivier; Bilancio, Antonio; Burns, Emily; Nock, Gemma E; Houseman, Benjamin; Shokat, Kevan; Ridley, Anne J; Vanhaesebroeck, Bart

    2008-12-15

    The class IA isoforms of phosphoinositide 3-kinase (p110alpha, p110beta and p110delta) often have non-redundant functions in a given cell type. However, for reasons that are unclear, the role of a specific PI3K isoform can vary between cell types. Here, we compare the relative contributions of PI3K isoforms in primary and immortalised macrophages. In primary macrophages stimulated with the tyrosine kinase ligand colony-stimulating factor 1 (CSF1), all class IA PI3K isoforms participate in the regulation of Rac1, whereas p110delta selectively controls the activities of Akt, RhoA and PTEN, in addition to controlling proliferation and chemotaxis. The prominent role of p110delta in these cells correlates with it being the main PI3K isoform that is recruited to the activated CSF1 receptor (CSF1R). In immortalised BAC1.2F5 macrophages, however, the CSF1R also engages p110alpha, which takes up a more prominent role in CSF1R signalling, in processes including Akt phosphorylation and regulation of DNA synthesis. Cell migration, however, remains dependent mainly on p110delta. In other immortalised macrophage cell lines, such as IC-21 and J774.2, p110alpha also becomes more prominently involved in CSF1-induced Akt phosphorylation, at the expense of p110delta.These data show that PI3K isoforms can be differentially regulated in distinct cellular contexts, with the dominant role of the p110delta isoform in Akt phosphorylation and proliferation being lost upon cell immortalisation. These findings suggest that p110delta-selective PI3K inhibitors may be more effective in inflammation than in cancer. PMID:19033389

  16. Effects of PI3K inhibition and low docosahexaenoic acid on cognition and behavior.

    PubMed

    Bandaru, Sathyajit S; Lin, Kristen; Roming, Stephanie L; Vellipuram, Ramana; Harney, Jacob P

    2010-06-01

    Alterations in two components of the brain's insulin signaling pathway, docosahexaenoic acid (DHA) content and phosphoinositide 3-kinase (PI3K) activity, have been implicated in the insulin resistance that is central to type II diabetes mellitus (DM). A 2- to 3-fold increased risk of developing Alzheimer's disease (AD) in patients with type II DM suggests a potential link between cognition and insulin action. The current study was designed to examine the impact of DHA dietary content and PI3K activity on learning, memory, depression, and anxiety in rodents. Mice were divided into the following groups: (1) control diet and vehicle injection (control PI3K), (2) control diet and wortmannin injection (PI3K inhibition), (3) low DHA diet and vehicle, and (4) low DHA diet and wortmannin. Each group was assessed for effects on activity, cognition, depression, and anxiety. Concentrations of glucose and insulin in plasma were quantified to confirm insulin resistance. Results showed significant increases in depression, anxiety, plasma insulin and glucose, and significant decreases in activity in wortmannin-treated mice regardless of diet. The control diet/wortmannin-treated group showed a significant decrease in memory compared to all other groups. The low DHA diet/wortmannin-treated group had slightly improved memory and lower levels of depression compared to the control diet/wortmannin-treated group. Results of the present study suggest that inhibition of PI3K decreases activity and memory while increasing insulin resistance, depression, and anxiety. In addition, these results suggest a possible compensatory role of low DHA in decreasing the effects of dysfunctional PI3K in AD associated cognitive decline and depression. PMID:19914265

  17. PI-3K Inhibitors Preferentially Target CD15+ Cancer Stem Cell Population in SHH Driven Medulloblastoma

    PubMed Central

    Singh, Alok R.; Joshi, Shweta; Zulcic, Muamera; Alcaraz, Michael; Garlich, Joseph R.; Morales, Guillermo A.; Cho, Yoon J.; Bao, Lei; Levy, Michael L.; Newbury, Robert; Malicki, Denise; Messer, Karen; Crawford, John; Durden, Donald L.

    2016-01-01

    Sonic hedgehog (SHH) medulloblastoma (MB) subtype is driven by a proliferative CD15+ tumor propagating cell (TPC), also considered in the literature as a putative cancer stem cell (CSC). Despite considerable research, much of the biology of this TPC remains unknown. We report evidence that phosphatase and tensin homolog (PTEN) and phosphoinositide 3-kinase (PI-3K) play a crucial role in the propagation, survival and potential response to therapy in this CD15+ CSC/TPC-driven malignant disease. Using the ND2-SmoA1 transgenic mouse model for MB, mouse genetics and patient-derived xenografts (PDXs), we demonstrate that the CD15+TPCs are 1) obligately required for SmoA1Tg-driven tumorigenicity 2) regulated by PTEN and PI-3K signaling 3) selectively sensitive to the cytotoxic effects of pan PI-3K inhibitors in vitro and in vivo but resistant to chemotherapy 4) in the SmoA1Tg mouse model are genomically similar to the SHH human MB subgroup. The results provide the first evidence that PTEN plays a role in MB TPC signaling and biology and that PI-3K inhibitors target and suppress the survival and proliferation of cells within the mouse and human CD15+ cancer stem cell compartment. In contrast, CD15+ TPCs are resistant to cisplatinum, temozolomide and the SHH inhibitor, NVP-LDE-225, agents currently used in treatment of medulloblastoma. These studies validate the therapeutic efficacy of pan PI-3K inhibitors in the treatment of CD15+ TPC dependent medulloblastoma and suggest a sequential combination of PI-3K inhibitors and chemotherapy will have augmented efficacy in the treatment of this disease. PMID:26938241

  18. PI-3K Inhibitors Preferentially Target CD15+ Cancer Stem Cell Population in SHH Driven Medulloblastoma.

    PubMed

    Singh, Alok R; Joshi, Shweta; Zulcic, Muamera; Alcaraz, Michael; Garlich, Joseph R; Morales, Guillermo A; Cho, Yoon J; Bao, Lei; Levy, Michael L; Newbury, Robert; Malicki, Denise; Messer, Karen; Crawford, John; Durden, Donald L

    2016-01-01

    Sonic hedgehog (SHH) medulloblastoma (MB) subtype is driven by a proliferative CD15+ tumor propagating cell (TPC), also considered in the literature as a putative cancer stem cell (CSC). Despite considerable research, much of the biology of this TPC remains unknown. We report evidence that phosphatase and tensin homolog (PTEN) and phosphoinositide 3-kinase (PI-3K) play a crucial role in the propagation, survival and potential response to therapy in this CD15+ CSC/TPC-driven malignant disease. Using the ND2-SmoA1 transgenic mouse model for MB, mouse genetics and patient-derived xenografts (PDXs), we demonstrate that the CD15+TPCs are 1) obligately required for SmoA1Tg-driven tumorigenicity 2) regulated by PTEN and PI-3K signaling 3) selectively sensitive to the cytotoxic effects of pan PI-3K inhibitors in vitro and in vivo but resistant to chemotherapy 4) in the SmoA1Tg mouse model are genomically similar to the SHH human MB subgroup. The results provide the first evidence that PTEN plays a role in MB TPC signaling and biology and that PI-3K inhibitors target and suppress the survival and proliferation of cells within the mouse and human CD15+ cancer stem cell compartment. In contrast, CD15+ TPCs are resistant to cisplatinum, temozolomide and the SHH inhibitor, NVP-LDE-225, agents currently used in treatment of medulloblastoma. These studies validate the therapeutic efficacy of pan PI-3K inhibitors in the treatment of CD15+ TPC dependent medulloblastoma and suggest a sequential combination of PI-3K inhibitors and chemotherapy will have augmented efficacy in the treatment of this disease. PMID:26938241

  19. PI3K Inhibitor Combined With Chemotherapy Can Enhance the Apoptosis of Neuroblastoma Cells In Vitro and In Vivo.

    PubMed

    Geng, Xianjie; Xie, Lingling; Xing, Hongshun

    2016-10-01

    Activation of the phosphoinositide 3-kinase (PI3K)/Akt signaling pathway is a novel poor prognostic indicator of neuroblastoma (NB), and the positive effects of chemotherapy on NB have been confirmed. In this study, we investigated the effect of small molecule PI3K inhibitor PI103 on chemosensitivity. The PI3K inhibitor cooperates with doxorubicin to synergistically induce apoptosis and to reduce tumor growth of NB in in vitro and in vivo models. Human NB cells, SH-SY5Y and SK-N-BE(2), were treated with PI103 combined doxorubicin-enhanced Bid cleavage, activated Bax, and caspase 3. Activation of caspase 3 was also observed in xenografts of NB in nude mice upon combination of doxorubicin with the specific PI3K inhibitor PI103. Cell viability was assessed with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays. Both PI103 and doxorubicin inhibited growth of NB in vitro and PI103 induced a G1 arrest of NB cells. PI103 combined doxorubicin significantly inhibits the growth of established NB tumors, induced apoptosis of tumor cells, and improved the survival of mice in vivo Taken together, our findings suggest that PI3K inhibition seems to be a promising option to sensitize tumor cells for chemotherapy in NB, which may be effective in the treatment of NBs.

  20. PI3K Inhibitor Combined With Chemotherapy Can Enhance the Apoptosis of Neuroblastoma Cells In Vitro and In Vivo.

    PubMed

    Geng, Xianjie; Xie, Lingling; Xing, Hongshun

    2016-10-01

    Activation of the phosphoinositide 3-kinase (PI3K)/Akt signaling pathway is a novel poor prognostic indicator of neuroblastoma (NB), and the positive effects of chemotherapy on NB have been confirmed. In this study, we investigated the effect of small molecule PI3K inhibitor PI103 on chemosensitivity. The PI3K inhibitor cooperates with doxorubicin to synergistically induce apoptosis and to reduce tumor growth of NB in in vitro and in vivo models. Human NB cells, SH-SY5Y and SK-N-BE(2), were treated with PI103 combined doxorubicin-enhanced Bid cleavage, activated Bax, and caspase 3. Activation of caspase 3 was also observed in xenografts of NB in nude mice upon combination of doxorubicin with the specific PI3K inhibitor PI103. Cell viability was assessed with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays. Both PI103 and doxorubicin inhibited growth of NB in vitro and PI103 induced a G1 arrest of NB cells. PI103 combined doxorubicin significantly inhibits the growth of established NB tumors, induced apoptosis of tumor cells, and improved the survival of mice in vivo Taken together, our findings suggest that PI3K inhibition seems to be a promising option to sensitize tumor cells for chemotherapy in NB, which may be effective in the treatment of NBs. PMID:26224681

  1. Trastuzumab-resistant cells rely on a HER2-PI3K-FoxO-survivin axis and are sensitive to PI3K inhibitors.

    PubMed

    Chakrabarty, Anindita; Bhola, Neil E; Sutton, Cammie; Ghosh, Ritwik; Kuba, María Gabriela; Dave, Bhuvanesh; Chang, Jenny C; Arteaga, Carlos L

    2013-02-01

    The antibody trastuzumab is approved for treatment of patients with HER2 (ERBB2)-overexpressing breast cancer. A significant fraction of these tumors are either intrinsically resistant or acquire resistance rendering the drug ineffective. The development of resistance has been attributed to failure of the antibody to inhibit phosphoinositide 3-kinase (PI3K), which is activated by the HER2 network. Herein, we examined the effects of PI3K blockade in trastuzumab-resistant breast cancer cell lines. Treatment with the pan-PI3K inhibitor XL147 and trastuzumab reduced proliferation and pAKT levels, triggering apoptosis of trastuzumab-resistant cells. Compared with XL147 alone, the combination exhibited a superior antitumor effect against trastuzumab-resistant tumor xenografts. Furthermore, treatment with XL147 and trastuzumab reduced the cancer stem-cell (CSC) fraction within trastuzumab-resistant cells both in vitro and in vivo. These effects were associated with FoxO-mediated inhibition of transcription of the antiapoptosis gene survivin (BIRC5) and the CSC-associated cytokine interleukin-8. RNA interference-mediated or pharmacologic inhibition of survivin restored sensitivity to trastuzumab in resistant cells. In a cohort of patients with HER2-overexpressing breast cancer treated with trastuzumab, higher pretreatment tumor levels of survivin RNA correlated with poor response to therapy. Together, our results suggest that survivin blockade is required for therapeutic responses to trastuzumab and that by combining trastuzumab and PI3K inhibitors, CSCs can be reduced within HER2(+) tumors, potentially preventing acquired resistance to anti-HER2 therapy.

  2. Following the trail of lipids: Signals initiated by PI3K function at multiple cellular membranes.

    PubMed

    Naguib, Adam

    2016-05-17

    Phosphatidylinositol 3,4,5-trisphosphate [PtdIns(3,4,5)P3] is the signaling currency of the phosphoinositide 3-kinase (PI3K)/AKT pathway; transduction through this axis depends on this signaling lipid. Formation of PtdIns(3,4,5)P3 is dictated not only by PI3K activation but also by the localization and access of PI3K to its substrate PtdIns(4,5)P2 (phosphatidylinositol 4,5-bisphosphate). PI3K/AKT-mediated signaling is antagonized by PtdIns(3,4,5)P3 dephosphorylation. Although previously typically considered an event associated with the plasma membrane, it is now appreciated that the formation and metabolism of PtdIns(3,4,5)P3 occur on multiple membranes with distinct kinetics. Modulated activity of phosphatidylinositol lipid kinases and phosphatases contributes to intricately orchestrated lipid gradients that define the signaling status of the pathway at multiple sites within the cell.

  3. Regulation of the PI3K pathway through a p85α monomer–homodimer equilibrium

    PubMed Central

    Cheung, Lydia WT; Walkiewicz, Katarzyna W; Besong, Tabot MD; Guo, Huifang; Hawke, David H; Arold, Stefan T; Mills, Gordon B

    2015-01-01

    The canonical action of the p85α regulatory subunit of phosphatidylinositol 3-kinase (PI3K) is to associate with the p110α catalytic subunit to allow stimuli-dependent activation of the PI3K pathway. We elucidate a p110α-independent role of homodimerized p85α in the positive regulation of PTEN stability and activity. p110α-free p85α homodimerizes via two intermolecular interactions (SH3:proline-rich region and BH:BH) to selectively bind unphosphorylated activated PTEN. As a consequence, homodimeric but not monomeric p85α suppresses the PI3K pathway by protecting PTEN from E3 ligase WWP2-mediated proteasomal degradation. Further, the p85α homodimer enhances the lipid phosphatase activity and membrane association of PTEN. Strikingly, we identified cancer patient-derived oncogenic p85α mutations that target the homodimerization or PTEN interaction surface. Collectively, our data suggest the equilibrium of p85α monomer–dimers regulates the PI3K pathway and disrupting this equilibrium could lead to disease development. DOI: http://dx.doi.org/10.7554/eLife.06866.001 PMID:26222500

  4. Thyroid hormone inhibits the proliferation of piglet Sertoli cell via PI3K signaling pathway.

    PubMed

    Sun, Yan; Yang, WeiRong; Luo, HongLin; Wang, XianZhong; Chen, ZhongQiong; Zhang, JiaoJiao; Wang, Yi; Li, XiaoMin

    2015-01-01

    Accumulating researches show that thyroid hormone (TH) inhibits Sertoli cells (SCs) proliferation and stimulates their functional maturation in prepubertal rat testis, confirming that TH plays a key role in testicular development. However, the mechanism under the T3 regulation of piglet SC proliferation remains unclear. In the present study, in order to investigate the possible mechanism of T3 on the suppression of SC proliferation, the expression pattern of TRα1 and cell cycle-related molecules, effect of T3 on SC proliferation, and the role of phosphoinositide 3-kinase (PI3K)/Akt signaling pathway on the T3-mediated SC proliferation in piglet testis were explored. Our results demonstrated that TRα1 was expressed in all tested stages of SCs and decreased along with the ages. T3 inhibited the proliferation of SCs in a time- and dose-dependent manner, and T3 treatment downregulated the expressions of cell cycling molecules, such as cyclinA2, cyclinD1, cyclinE1, PCNA, and Skp2, but upregulated the p27 expression in SCs. Most importantly, the suppressive effects of T3 on SC proliferation seemed dependent on the inhibition of PI3K/Akt signaling pathway, and pre-stimulation of PI3K could enhance such suppressive effects. Together, our findings demonstrate that TH inhibits the proliferation of piglet SCs via the suppression of PI3K/Akt signaling pathway.

  5. PI3K{gamma} activation by CXCL12 regulates tumor cell adhesion and invasion

    SciTech Connect

    Monterrubio, Maria; Mellado, Mario; Carrera, Ana C.

    2009-10-16

    Tumor dissemination is a complex process, in which certain steps resemble those in leukocyte homing. Specific chemokine/chemokine receptor pairs have important roles in both processes. CXCL12/CXCR4 is the most commonly expressed chemokine/chemokine receptor pair in human cancers, in which it regulates cell adhesion, extravasation, metastatic colonization, angiogenesis, and proliferation. All of these processes require activation of signaling pathways that include G proteins, phosphatidylinositol-3 kinase (PI3K), JAK kinases, Rho GTPases, and focal adhesion-associated proteins. We analyzed these pathways in a human melanoma cell line in response to CXCL12 stimulation, and found that PI3K{gamma} regulates tumor cell adhesion through mechanisms different from those involved in cell invasion. Our data indicate that, following CXCR4 activation after CXCL12 binding, the invasion and adhesion processes are regulated differently by distinct downstream events in these signaling cascades.

  6. The PI3K/Akt Pathway in Tumors of Endocrine Tissues

    PubMed Central

    Robbins, Helen Louise; Hague, Angela

    2016-01-01

    The phosphatidylinositol 3-kinase (PI3K)/Akt pathway is a key driver in carcinogenesis. Defects in this pathway in human cancer syndromes such as Cowden’s disease and Multiple Endocrine Neoplasia result in tumors of endocrine tissues, highlighting its importance in these cancer types. This review explores the growing evidence from multiple animal and in vitro models and from analysis of human tumors for the involvement of this pathway in the following: thyroid carcinoma subtypes, parathyroid carcinoma, pituitary tumors, adrenocortical carcinoma, phaeochromocytoma, neuroblastoma, and gastroenteropancreatic neuroendocrine tumors. While data are not always consistent, immunohistochemistry performed on human tumor tissue has been used alongside other techniques to demonstrate Akt overactivation. We review active Akt as a potential prognostic marker and the PI3K pathway as a therapeutic target in endocrine neoplasia. PMID:26793165

  7. PI3K therapy reprograms mitochondrial trafficking to fuel tumor cell invasion.

    PubMed

    Caino, M Cecilia; Ghosh, Jagadish C; Chae, Young Chan; Vaira, Valentina; Rivadeneira, Dayana B; Faversani, Alice; Rampini, Paolo; Kossenkov, Andrew V; Aird, Katherine M; Zhang, Rugang; Webster, Marie R; Weeraratna, Ashani T; Bosari, Silvano; Languino, Lucia R; Altieri, Dario C

    2015-07-14

    Molecular therapies are hallmarks of "personalized" medicine, but how tumors adapt to these agents is not well-understood. Here we show that small-molecule inhibitors of phosphatidylinositol 3-kinase (PI3K) currently in the clinic induce global transcriptional reprogramming in tumors, with activation of growth factor receptors, (re)phosphorylation of Akt and mammalian target of rapamycin (mTOR), and increased tumor cell motility and invasion. This response involves redistribution of energetically active mitochondria to the cortical cytoskeleton, where they support membrane dynamics, turnover of focal adhesion complexes, and random cell motility. Blocking oxidative phosphorylation prevents adaptive mitochondrial trafficking, impairs membrane dynamics, and suppresses tumor cell invasion. Therefore, "spatiotemporal" mitochondrial respiration adaptively induced by PI3K therapy fuels tumor cell invasion, and may provide an important antimetastatic target. PMID:26124089

  8. PI3K therapy reprograms mitochondrial trafficking to fuel tumor cell invasion

    PubMed Central

    Caino, M. Cecilia; Ghosh, Jagadish C.; Chae, Young Chan; Vaira, Valentina; Rivadeneira, Dayana B.; Faversani, Alice; Rampini, Paolo; Kossenkov, Andrew V.; Aird, Katherine M.; Zhang, Rugang; Webster, Marie R.; Weeraratna, Ashani T.; Bosari, Silvano; Languino, Lucia R.; Altieri, Dario C.

    2015-01-01

    Molecular therapies are hallmarks of “personalized” medicine, but how tumors adapt to these agents is not well-understood. Here we show that small-molecule inhibitors of phosphatidylinositol 3-kinase (PI3K) currently in the clinic induce global transcriptional reprogramming in tumors, with activation of growth factor receptors, (re)phosphorylation of Akt and mammalian target of rapamycin (mTOR), and increased tumor cell motility and invasion. This response involves redistribution of energetically active mitochondria to the cortical cytoskeleton, where they support membrane dynamics, turnover of focal adhesion complexes, and random cell motility. Blocking oxidative phosphorylation prevents adaptive mitochondrial trafficking, impairs membrane dynamics, and suppresses tumor cell invasion. Therefore, “spatiotemporal” mitochondrial respiration adaptively induced by PI3K therapy fuels tumor cell invasion, and may provide an important antimetastatic target. PMID:26124089

  9. Ganoderma atrum polysaccharide improves aortic relaxation in diabetic rats via PI3K/Akt pathway.

    PubMed

    Zhu, Ke-Xue; Nie, Shao-Ping; Li, Chuan; Gong, Deming; Xie, Ming-Yong

    2014-03-15

    A newly identified polysaccharide (PSG-1) has been purified from Ganoderma atrum. The study was to investigate the protective effect of PSG-1 on diabetes-induced endothelial dysfunction in rat aorta. Rats were fed a high fat diet for 8 weeks and then injected with a low dose of streptozotocin to induce type 2 diabetes. The diabetic rats were orally treated with PSG-1 for 4 weeks. It was found that administration of PSG-1 significantly reduced levels of fasting blood glucose, improved endothelium-dependent aortic relaxation, increased levels of phosphoinositide 3-kinase (PI3K), phospho-Akt (p-Akt), endothelial nitric oxide synthase (eNOS) and nitric oxide in the aorta from diabetic rats, compared to un-treated diabetics. These results suggested that the protective effects of PSG-1 against endothelial dysfunction may be related to activation of the PI3K/Akt/eNOS pathway.

  10. The role of PI3K/Akt in human herpesvirus infection: From the bench to the bedside.

    PubMed

    Liu, XueQiao; Cohen, Jeffrey I

    2015-05-01

    The phosphatidylinositol-3-kinase (PI3K)-Akt signaling pathway regulates several key cellular functions including protein synthesis, cell growth, glucose metabolism, and inflammation. Many viruses have evolved mechanisms to manipulate this signaling pathway to ensure successful virus replication. The human herpesviruses undergo both latent and lytic infection, but differ in cell tropism, growth kinetics, and disease manifestations. Herpesviruses express multiple proteins that target the PI3K/Akt cell signaling pathway during the course of their life cycle to facilitate viral infection, replication, latency, and reactivation. Rare human genetic disorders with mutations in either the catalytic or regulatory subunit of PI3K that result in constitutive activation of the protein predispose to severe herpesvirus infections as well as to virus-associated malignancies. Inhibiting the PI3K/Akt pathway or its downstream proteins using drugs already approved for other diseases can block herpesvirus lytic infection and may reduce malignancies associated with latent herpesvirus infections. PMID:25798530

  11. Coordinate activation of Shh and PI3K signaling in PTEN-deficient glioblastoma: new therapeutic opportunities.

    PubMed

    Filbin, Mariella Gruber; Dabral, Sukriti K; Pazyra-Murphy, Maria F; Ramkissoon, Shakti; Kung, Andrew L; Pak, Ekaterina; Chung, Jarom; Theisen, Matthew A; Sun, Yanping; Franchetti, Yoko; Sun, Yu; Shulman, David S; Redjal, Navid; Tabak, Barbara; Beroukhim, Rameen; Wang, Qi; Zhao, Jean; Dorsch, Marion; Buonamici, Silvia; Ligon, Keith L; Kelleher, Joseph F; Segal, Rosalind A

    2013-11-01

    In glioblastoma, phosphatidylinositol 3-kinase (PI3K) signaling is frequently activated by loss of the tumor suppressor phosphatase and tensin homolog (PTEN). However, it is not known whether inhibiting PI3K represents a selective and effective approach for treatment. We interrogated large databases and found that sonic hedgehog (SHH) signaling is activated in PTEN-deficient glioblastoma. We demonstrate that the SHH and PI3K pathways synergize to promote tumor growth and viability in human PTEN-deficient glioblastomas. A combination of PI3K and SHH signaling inhibitors not only suppressed the activation of both pathways but also abrogated S6 kinase (S6K) signaling. Accordingly, targeting both pathways simultaneously resulted in mitotic catastrophe and tumor apoptosis and markedly reduced the growth of PTEN-deficient glioblastomas in vitro and in vivo. The drugs tested here appear to be safe in humans; therefore, this combination may provide a new targeted treatment for glioblastoma. PMID:24076665

  12. The Role of PI3K/Akt in Human Herpesvirus Infection: from the Bench to the Bedside

    PubMed Central

    Liu, XueQiao; Cohen, Jeffrey I.

    2015-01-01

    The phosphatidylinositol-3-kinase (PI3K)-Akt signaling pathway regulates several key cellular functions including protein synthesis, cell growth, glucose metabolism, and inflammation. Many viruses have evolved mechanisms to manipulate this signaling pathway to ensure successful virus replication. The human herpesviruses undergo both latent and lytic infection, but differ in cell tropism, growth kinetics, and disease manifestations. Herpesviruses express multiple proteins that target the PI3K/Akt cell signaling pathway during the course of their life cycle to facilitate viral infection, replication, latency, and reactivation. Rare human genetic disorders with mutations in either the catalytic or regulatory subunit of PI3K that result in constitutive activation of the protein predispose to severe herpesvirus infections as well as to virus-associated malignancies. Inhibiting the PI3K/Akt pathway or its downstream proteins using drugs already approved for other diseases can block herpesvirus lytic infection and may reduce malignancies associated with latent herpesvirus infections. PMID:25798530

  13. Discovery of GSK2126458, a Highly Potent Inhibitor of PI3K and the Mammalian Target of Rapamycin

    SciTech Connect

    Knight, Steven D.; Adams, Nicholas D.; Burgess, Joelle L.; Chaudhari, Amita M.; Darcy, Michael G.; Donatelli, Carla A.; Luengo, Juan I.; Newlander, Ken A.; Parrish, Cynthia A.; Ridgers, Lance H.; Sarpong, Martha A.; Schmidt, Stanley J.; Aller, Glenn S.Van; Carson, Jeffrey D.; Diamond, Melody A.; Elkins, Patricia A.; Gardiner, Christine M.; Garver, Eric; Gilbert, Seth A.; Gontarek, Richard R.; Jackson, Jeffrey R.; Kershner, Kevin L.; Luo, Lusong; Raha, Kaushik; Sherk, Christian S.; Sung, Chiu-Mei; Sutton, David; Tummino, Peter J.; Wegrzyn, Ronald J.; Auger, Kurt R.; Dhanak, Dashyant

    2010-09-30

    Phosphoinositide 3-kinase {alpha} (PI3K{alpha}) is a critical regulator of cell growth and transformation, and its signaling pathway is the most commonly mutated pathway in human cancers. The mammalian target of rapamycin (mTOR), a class IV PI3K protein kinase, is also a central regulator of cell growth, and mTOR inhibitors are believed to augment the antiproliferative efficacy of PI3K/AKT pathway inhibition. 2,4-Difluoro-N-{l_brace}2-(methyloxy)-5-[4-(4-pyridazinyl)-6-quinolinyl]-3-pyridinyl{r_brace}benzenesulfonamide (GSK2126458, 1) has been identified as a highly potent, orally bioavailable inhibitor of PI3K{alpha} and mTOR with in vivo activity in both pharmacodynamic and tumor growth efficacy models. Compound 1 is currently being evaluated in human clinical trials for the treatment of cancer.

  14. Exploration of a potent PI3 kinase/mTOR inhibitor as a novel anti-fibrotic agent in IPF

    PubMed Central

    Mercer, Paul F; Woodcock, Hannah V; Eley, Jessica D; Platé, Manuela; Sulikowski, Michal G; Durrenberger, Pascal F; Franklin, Linda; Nanthakumar, Carmel B; Man, Yim; Genovese, Federica; McAnulty, Robin J; Yang, Shuying; Maher, Toby M; Nicholson, Andrew G; Blanchard, Andy D; Marshall, Richard P; Lukey, Pauline T; Chambers, Rachel C

    2016-01-01

    Rationale Idiopathic pulmonary fibrosis (IPF) is the most rapidly progressive and fatal of all fibrotic conditions with no curative therapies. Common pathomechanisms between IPF and cancer are increasingly recognised, including dysfunctional pan-PI3 kinase (PI3K) signalling as a driver of aberrant proliferative responses. GSK2126458 is a novel, potent, PI3K/mammalian target of rapamycin (mTOR) inhibitor which has recently completed phase I trials in the oncology setting. Our aim was to establish a scientific and dosing framework for PI3K inhibition with this agent in IPF at a clinically developable dose. Methods We explored evidence for pathway signalling in IPF lung tissue and examined the potency of GSK2126458 in fibroblast functional assays and precision-cut IPF lung tissue. We further explored the potential of IPF patient-derived bronchoalveolar lavage (BAL) cells to serve as pharmacodynamic biosensors to monitor GSK2126458 target engagement within the lung. Results We provide evidence for PI3K pathway activation in fibrotic foci, the cardinal lesions in IPF. GSK2126458 inhibited PI3K signalling and functional responses in IPF-derived lung fibroblasts, inhibiting Akt phosphorylation in IPF lung tissue and BAL derived cells with comparable potency. Integration of these data with GSK2126458 pharmacokinetic data from clinical trials in cancer enabled modelling of an optimal dosing regimen for patients with IPF. Conclusions Our data define PI3K as a promising therapeutic target in IPF and provide a scientific and dosing framework for progressing GSK2126458 to clinical testing in this disease setting. A proof-of-mechanism trial of this agent is currently underway. Trial registration number NCT01725139, pre-clinical. PMID:27103349

  15. Sequential application of a cytotoxic nanoparticle and a PI3K inhibitor enhances antitumor efficacy

    PubMed Central

    Pandey, Ambarish; Goldman, Aaron; Sarangi, Sasmit; Sengupta, Poulomi; Phipps, Colin; Kopparam, Jawahar; Oh, Michael; Basu, Sudipta; Kohandel, Mohammad; Sengupta, Shiladitya

    2013-01-01

    Nanomedicines that preferentially deploy cytotoxic agents to tumors, and molecular targeted therapeutics that inhibit specific aberrant oncogenic drivers are emerging as the new paradigm for the management of cancer. While combination therapies are a mainstay of cancer chemotherapy, few studies have addressed the combination of nanomedicines and molecular targeted therapeutics. Furthermore, limited knowledge exists on the impact of sequencing of such therapeutics and nanomedicines on the antitumor outcome. Here we engineered a supramolecular cis-platinum nanoparticle, which induced apoptosis in breast cancer cells but also elicited pro-survival signaling via an epidermal growth factor receptor-phosphatidylinositol 3 kinase (PI3K) pathway. A combination of mathematical modeling and in vitro and in vivo validation using a pharmacological inhibitor of PI3K, PI828, demonstrate that administration of PI828 following treatment with the supramolecular cis-platinum nanoparticle results in enhanced antitumor efficacy in breast cancer as compared with when the sequence is reversed or when the two treatments are administered simultaneously. This study addresses, for the first time, the impact of drug sequencing in the case of a combination of a nanomedicine and a targeted therapeutic. Furthermore, our results indicate that a rational combination of cis-platinum nanoparticles and a PI3K-targeted therapeutic can emerge as a potential therapy for breast cancer. PMID:24121494

  16. Implication of PI3K/Akt pathway in pancreatic cancer: When PI3K isoforms matter?

    PubMed

    Baer, Romain; Cintas, Célia; Therville, Nicole; Guillermet-Guibert, Julie

    2015-09-01

    Pancreatic cancer belongs to the incurable family of solid cancers. Despite of a recent better understanding its molecular biology, and an increased number of clinical trials, there is still a lack for innovative targeted therapies to fight this deadly malignancy. PI3K/Akt signalling is one of the most commonly deregulated signalling pathways in cancer, which explains the massive attention from many pharmaceutical companies over the ten past years on these signalling molecules. The already developed small molecule inhibitors are currently under clinical trial in various cancer types. Class I PI3Ks have 4 isoforms for which the role in physiology starts to be well described in the literature. Data are more unclear for their differential involvement in oncogenesis. In this review, we will discuss about the cognitive and therapeutic potential of targeting this signalling pathway and in particular Class I PI3K isoforms for pancreatic cancer treatment. Isoform-specificity of PI3K inhibitors are currently designed to achieve the same goal as pan-PI3K inhibitors but without potential adverse effects. We will discuss if such strategy is relevant in pancreatic adenocarcinoma.

  17. The Emerging Role of PI3K Inhibitors in the Treatment of Hematological Malignancies: Preclinical Data and Clinical Progress to Date.

    PubMed

    Seiler, Till; Hutter, Grit; Dreyling, Martin

    2016-04-01

    The phosphoinositide 3-kinase (PI3K)/Akt/mTOR pathway is implicated in the pathogenesis of lymphoma. Deeper understanding of the diversity and biological impact of this pathway has led to the development of specific inhibitors to this pathway. Preclinical data in cell lines, patient samples and disease models have broadened our understanding of PI3K inhibition. Several PI3K inhibitors are currently in advanced stages of clinical development. Idelalisib is the first agent of this new substance class to be approved in chronic lymphocytic leukemia and follicular lymphoma. Other agents specifically target different PI3K isoforms and show promising clinical efficacy. PMID:27052260

  18. Regulation of mRNA export by the PI3 kinase/AKT signal transduction pathway

    PubMed Central

    Quaresma, Alexandre Jose Christino; Sievert, Rachel; Nickerson, Jeffrey A.

    2013-01-01

    UAP56, ALY/REF, and NXF1 are mRNA export factors that sequentially bind at the 5′ end of a nuclear mRNA but are also reported to associate with the exon junction complex (EJC). To screen for signal transduction pathways regulating mRNA export complex assembly, we used fluorescence recovery after photobleaching to measure the binding of mRNA export and EJC core proteins in nuclear complexes. The fraction of UAP56, ALY/REF, and NXF1 tightly bound in complexes was reduced by drug inhibition of the phosphatidylinositide 3-kinase (PI3 kinase)/AKT pathway, as was the tightly bound fraction of the core EJC proteins eIF4A3, MAGOH, and Y14. Inhibition of the mTOR mTORC1 pathway decreased the tight binding of MAGOH. Inhibition of the PI3 kinase/AKT pathway increased the export of poly(A) RNA and of a subset of candidate mRNAs. A similar effect of PI3 kinase/AKT inhibition was observed for mRNAs from both intron-containing and intronless histone genes. However, the nuclear export of mRNAs coding for proteins targeted to the endoplasmic reticulum or to mitochondria was not affected by the PI3 kinase/AKT pathway. These results show that the active PI3 kinase/AKT pathway can regulate mRNA export and promote the nuclear retention of some mRNAs. PMID:23427269

  19. Simultaneous Inhibition of EGFR and PI3K Enhances Radiosensitivity in Human Breast Cancer

    SciTech Connect

    Li Ping; Zhang Qing; Torossian, Artour; Li Zhaobin; Xu Wencai; Lu Bo; Fu Shen

    2012-07-01

    Purpose: Mutations in the epidermal growth factor receptor (EGFR)/phosphoinositide 3-kinase (PI3K)/Akt signaling transduction pathway are common in cancer. This pathway is imperative to the radiosensitivity of cancer cells. We aimed to investigate the radiosensitizing effects of the simultaneous inhibition of EGFR and PI3K in breast cancer cells. Methods and Materials: MCF-7 cell lines with low expression of EGFR and wild-type PTEN and MDA-MB-468 cell lines with high expression of EGFR and mutant PTEN were used. The radiosensitizing effects by the inhibition of EGFR with AG1478 and/or PI3K with Ly294002 were determined by colony formation assay, Western blot was used to investigate the effects on downstream signaling. Flow cytometry was used for apoptosis and cell cycle analysis. Mice-bearing xenografts of MDA-MB-468 breast cancer cells were also used to observe the radiosensitizing effect. Results: Simultaneous inhibition of EGFR and PI3K greatly enhanced radiosensitizing effect in MDA-MB-468 in terms of apoptosis and mitotic death, either inhibition of EGFR or PI3K alone could enhance radiosensitivity with a dose-modifying factor (DMF{sub SF2}) of 1.311 and 1.437, radiosensitizing effect was further enhanced by simultaneous inhibition of EGFR and PI3K with a DMF{sub SF2} at 2.698. DNA flow cytometric analysis indicated that dual inhibition combined with irradiation significantly induced G0/G1 phase arrest in MDA-MB-468 cells. The expression of phosphor-Akt and phosphor-Erk1/2 (induced by irradiation and PI3K inhibitor) were fully attenuated by simultaneous treatment with both inhibitors in combination with irradiation. In addition, dual inhibition combined with irradiation induced dramatic tumor growth delay in MDA-MB-468 xenografts. Conclusions: Our study indicated that simultaneous inhibition of EGFR and PI3K could further sensitize the cancer cells to irradiation compared to the single inhibitor with irradiation in vitro and in vivo. The approach may have

  20. p70S6 kinase is a critical node that integrates HER-family and PI3 kinase signaling networks

    PubMed Central

    Axelrod, Mark J.; Gordon, Vicki; Mendez, Rolando E.; Leimgruber, Stephanie S.; Conaway, Mark R.; Sharlow, Elizabeth R.; Jameson, MarkJ.; Gioeli, Daniel G.; Weber, Michael J.

    2014-01-01

    Therapies targeting oncogenic drivers rapidly induce compensatory adaptive responses that blunt drug effectiveness, contributing to therapeutic resistance. Adaptive responses are characteristic of robust cell signaling networks, and thus there is increasing interest in drug combinations that co-target the driver and the adaptive response. An alternative approach to co-inhibiting oncogenic and adaptive targets is to identify a critical node where the activities of these targets converge. Nodes of convergence between signaling modules represent potential therapeutic vulnerabilities because their inhibition could result in collapse of the network, leading to enhanced cytotoxicity. In this report we demonstrate that p70S6 kinase (p70S6K) can function as a critical node linking HER-family and phosphoinositide-3-kinase (PI3K) pathway signaling. We used high-throughput combinatorial drug screening to identify adaptive survival responses to targeted therapies, and found that HER-family and PI3K represented compensatory signaling pathways. Co-targeting these pathways with drug combinations caused synergistic cytotoxicity in cases where inhibition of neither target was effective as a monotherapy. We utilized Reverse Phase Protein Arrays and determined that phosphorylation of ribosomal protein S6 was synergistically down-regulated upon HER-family and PI3K/mammalian target of rapamycin (mTOR) co-inhibition. Expression of constitutively active p70S6K protected against apoptosis induced by combined HER-family and PI3K/mTOR inhibition. Direct inhibition of p70S6K with small molecule inhibitors phenocopied HER-family and PI3K/mTOR co-inhibition. These data implicate p70S6K as a critical node in the HER-family/PI3K signaling network. The ability of direct inhibitors of p70S6K to phenocopy co-inhibition of two upstream signaling targets indicates that identification and targeting of critical nodes can overcome adaptive resistance to targeted therapies. PMID:24662264

  1. Genetic enhancement of behavioral itch responses in mice lacking phosphoinositide 3-kinase-γ (PI3Kγ)

    PubMed Central

    2011-01-01

    Phosphoinositide 3-kinases (PI3Ks) are important for synaptic plasticity and various brain functions. The only class IB isoform of PI3K, PI3Kγ, has received the most attention due to its unique roles in synaptic plasticity and cognition. However, the potential role of PI3Kγ in sensory transmission, such as pain and itch has not been examined. In this study, we present the evidence for the first time, that genetic deletion of PI3Kγ enhanced scratching behaviours in histamine-dependent and protease-activated receptor 2 (PAR-2)-dependent itch. In contrast, PI3Kγ-deficient mice did not exhibit enhanced scratching in chloroquine-induced itch, suggesting that PI3Kγ selectively contributes to certain types of behavioal itch response. Furthermore, PI3Kγ-deficient mice exhibited normal acute nociceptive responses to thermal and mechanical noxious stimuli. Behavioral licking responses to intraplantar injections of formalin and mechanical allodynia in a chronic inflammatory pain model (CFA) were also not affected by PI3Kγ gene deletion. Our findings indicate that PI3Kγ selectively contributes to behavioral itching induced by histamine and PAR-2 agonist, but not chloroquine agonist. PMID:22168443

  2. Gene-Environment Interactions Target Mitogen-activated Protein 3 Kinase 1 (MAP3K1) Signaling in Eyelid Morphogenesis*

    PubMed Central

    Mongan, Maureen; Meng, Qinghang; Wang, Jingjing; Kao, Winston W.-Y.; Puga, Alvaro; Xia, Ying

    2015-01-01

    Gene-environment interactions determine the biological outcomes through mechanisms that are poorly understood. Mouse embryonic eyelid closure is a well defined model to study the genetic control of developmental programs. Using this model, we investigated how exposure to dioxin-like environmental pollutants modifies the genetic risk of developmental abnormalities. Our studies reveal that mitogen-activated protein 3 kinase 1 (MAP3K1) signaling is a focal point of gene-environment cross-talk. Dioxin exposure, acting through the aryl hydrocarbon receptor (AHR), blocked eyelid closure in genetic mutants in which MAP3K1 signaling was attenuated but did not disturb this developmental program in either wild type or mutant mice with attenuated epidermal growth factor receptor or WNT signaling. Exposure also markedly inhibited c-Jun phosphorylation in Map3k1+/− embryonic eyelid epithelium, suggesting that dioxin-induced AHR pathways can synergize with gene mutations to inhibit MAP3K1 signaling. Our studies uncover a novel mechanism through which the dioxin-AHR axis interacts with the MAP3K1 signaling pathways during fetal development and provide strong empirical evidence that specific gene alterations can increase the risk of developmental abnormalities driven by environmental pollutant exposure. PMID:26109068

  3. PfIRR Interacts with HrIGF-I and Activates the MAP-kinase and PI3-kinase Signaling Pathways to Regulate Glycogen Metabolism in Pinctada fucata

    PubMed Central

    Shi, Yu; He, Mao-xian

    2016-01-01

    The insulin-induced mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K) pathways are major intracellular signaling modules and conserved among eukaryotes that are known to regulate diverse cellular processes. However, they have not been investigated in the mollusk species Pinctada fucata. Here, we demonstrate that insulin-related peptide receptor of P. fucata (pfIRR) interacts with human recombinant insulin-like growth factor I (hrIGF-I), and stimulates the MAPK and PI3K signaling pathways in P. fucata oocytes. We also show that inhibition of pfIRR by the inhibitor PQ401 significantly attenuates the basal and hrIGF-I-induced phosphorylation of MAPK and PI3K/Akt at amino acid residues threonine 308 and serine 473. Furthermore, our experiments show that there is cross-talk between the MAPK and PI3K/Akt pathways, in which MAPK kinase positively regulates the PI3K pathway, and PI3K positively regulates the MAPK cascade. Intramuscular injection of hrIGF-I stimulates the PI3K and MAPK pathways to increase the expression of pfirr, protein phosphatase 1, glucokinase, and the phosphorylation of glycogen synthase, decreases the mRNA expression of glycogen synthase kinase-3 beta, decreases glucose levels in hemocytes, and increases glycogen levels in digestive glands. These results suggest that the MAPK and PI3K pathways in P. fucata transmit the hrIGF-I signal to regulate glycogen metabolism. PMID:26911653

  4. PfIRR Interacts with HrIGF-I and Activates the MAP-kinase and PI3-kinase Signaling Pathways to Regulate Glycogen Metabolism in Pinctada fucata.

    PubMed

    Shi, Yu; He, Mao-xian

    2016-01-01

    The insulin-induced mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K) pathways are major intracellular signaling modules and conserved among eukaryotes that are known to regulate diverse cellular processes. However, they have not been investigated in the mollusk species Pinctada fucata. Here, we demonstrate that insulin-related peptide receptor of P. fucata (pfIRR) interacts with human recombinant insulin-like growth factor I (hrIGF-I), and stimulates the MAPK and PI3K signaling pathways in P. fucata oocytes. We also show that inhibition of pfIRR by the inhibitor PQ401 significantly attenuates the basal and hrIGF-I-induced phosphorylation of MAPK and PI3K/Akt at amino acid residues threonine 308 and serine 473. Furthermore, our experiments show that there is cross-talk between the MAPK and PI3K/Akt pathways, in which MAPK kinase positively regulates the PI3K pathway, and PI3K positively regulates the MAPK cascade. Intramuscular injection of hrIGF-I stimulates the PI3K and MAPK pathways to increase the expression of pfirr, protein phosphatase 1, glucokinase, and the phosphorylation of glycogen synthase, decreases the mRNA expression of glycogen synthase kinase-3 beta, decreases glucose levels in hemocytes, and increases glycogen levels in digestive glands. These results suggest that the MAPK and PI3K pathways in P. fucata transmit the hrIGF-I signal to regulate glycogen metabolism.

  5. Activity-dependent survival of developing neocortical neurons depends on PI3K signalling.

    PubMed

    Wagner-Golbs, Antje; Luhmann, Heiko J

    2012-02-01

    Spontaneous electrical network activity plays a major role in the control of cell survival in the developing brain. Several intracellular pathways are implicated in transducing electrical activity into gene expression dependent and independent survival signals. These include activation of phosphatidylinositol 3-kinase (PI3K) and its downstream effector Akt, activation of Ras and subsequently MAPK/extracellular signal-regulated kinase (MEK) and extracellular signal-regulated kinase and signalling via calcium/calmodulin-dependent protein kinase (CaMK). In the present study, we analyzed the role of these pathways for the control of neuronal survival in different extracellular potassium concentrations ([K(+) ](ex) ). Organotypic neocortical slice cultures prepared from newborn mice were kept in 5.3, 8.0 and 25.0mM [K(+) ](ex) and treated with specific inhibitors of PI3K, MEK1, CaMKK and a broad spectrum CaMK inhibitor. After 6h of incubation, slices were immunostained for activated caspase 3 (a-caspase 3) and the number of apoptotic cells was quantified by computer based analysis. We found that in 5.3 and 8.0mM [K(+) ](ex) only PI3K was important for neuronal survival. When [K(+) ](ex) was raised to 25.0mM, a concentration above the depolarization block, we found no influence of PI3K on neuronal survival. Our data demonstrate that only the PI3K pathway, and not the MEK1, CaMKK or CaMKs pathway, plays a central role in the regulation of activity-dependent neuronal survival in the developing cerebral cortex.

  6. Insulin inhibits inflammation and promotes atherosclerotic plaque stability via PI3K-Akt pathway activation.

    PubMed

    Yan, Hao; Ma, Ying; Li, Yan; Zheng, Xiaohui; Lv, Ping; Zhang, Yuan; Li, Jia; Ma, Meijuan; Zhang, Le; Li, Congye; Zhang, Rongqing; Gao, Feng; Wang, Haichang; Tao, Ling

    2016-02-01

    Toll-like receptor (TLR) 4 induced inflammation was reported to play an important role in atherosclerotic plaque stability. Recent studies indicated that insulin could inhibit inflammation by activating phosphatidylinositol 3-kinase-Akt-dependent (PI3K-Akt) signaling pathway. In the current study, we hypothesized that insulin would inhibit TLR4 induced inflammation via promoting PI3K-Akt activation, thus enhancing the stabilization of atherosclerotic plaques. In order to mimic the process of plaque formation, monocyte-macrophage lineage RAW264.7 were cultured and induced to form foam cells by oxidized LDL (ox-LDL). Oil red O staining results showed that insulin significantly restrained ox-LDL-induced foam cell formation. Analysis of inflammatory reaction during foam cell formation indicated that insulin significantly down-regulated the expression of tumor necrosis factor (TNF)-α, interleukin (IL)-6 levels, inhibited TLR4, myeloid differentiation primary response gene (MyD) 88 and nuclear factor (NF)-κB. Further mechanism analysis showed that pretreating with the PI3K blocker, wortmannin dramatically dampened the insulin-induced up-regulation of pAkt expression. Additionally, blockade of PI3K-Akt signaling also dampened the immunosuppression effect brought by insulin. Following the construction of a rodent atherosclerosis model, pretreatment of insulin resulted in an evident decrease in lipid deposition of the blood vessel wall, serum levels of TNF-α and IL-6, and numbers of infiltrated macrophages and foam cells. Taken together, these results suggested that insulin might inhibit inflammation and promote atherosclerotic plaque stability via the PI3K-Akt pathway by targeting TLR4-MyD88-NF-κB signaling. Our findings may provide a potential target for the prevention of cardiovascular disease. PMID:26681144

  7. Regulation of the PI3K pathway through a p85α monomer–homodimer equilibrium | Office of Cancer Genomics

    Cancer.gov

    The canonical action of the p85α regulatory subunit of phosphatidylinositol 3-kinase (PI3K) is to associate with the p110α catalytic subunit to allow stimuli-dependent activation of the PI3K pathway. We elucidate a p110α-independent role of homodimerized p85α in the positive regulation of PTEN stability and activity. p110α-free p85α homodimerizes via two intermolecular interactions (SH3:proline-rich region and BH:BH) to selectively bind unphosphorylated activated PTEN.

  8. Structural Effects of Oncogenic PI3K alpha Mutations

    SciTech Connect

    S Gabelli; C Huang; D Mandelker; O Schmidt-Kittler; B Vogelstein; L Amzel

    2011-12-31

    Physiological activation of PI3K{alpha} is brought about by the release of the inhibition by p85 when the nSH2 binds the phosphorylated tyrosine of activated receptors or their substrates. Oncogenic mutations of PI3K{alpha} result in a constitutively activated enzyme that triggers downstream pathways that increase tumor aggressiveness and survival. Structural information suggests that some mutations also activate the enzyme by releasing p85 inhibition. Other mutations work by different mechanisms. For example, the most common mutation, His1047Arg, causes a conformational change that increases membrane association resulting in greater accessibility to the substrate, an integral membrane component. These effects are examples of the subtle structural changes that result in increased activity. The structures of these and other mutants are providing the basis for the design of isozyme-specific, mutation-specific inhibitors for individualized cancer therapies.

  9. Heregulin-ErbB3-Driven Tumor Growth Persists in PI3 Kinase Mutant Cancer Cells.

    PubMed

    Yarar, Defne; Lahdenranta, Johanna; Kubasek, William; Nielsen, Ulrik B; MacBeath, Gavin

    2015-09-01

    PI3K is frequently mutated in cancer and plays an important role in cell growth and survival. Heregulin (HRG)-mediated autocrine or paracrine signaling through the receptor tyrosine kinase ErbB3 potently activates the PI3K/AKT pathway and has been shown to mediate resistance to a wide variety of anticancer agents. Although PI3K functions downstream of HRG-ErbB3, it is unknown whether activating mutations in PI3K render HRG ineffective. If so, patients with PI3K mutations would not be expected to benefit from ErbB3-directed therapies. Here, we find that a subset of cell lines harboring activating PI3K mutations can be further growth-stimulated by HRG, and this effect is blocked by incubation with seribantumab (MM-121), a monoclonal anti-ErbB3 antibody. Although expression of mutant PI3K in wild-type PI3K cells frequently results in loss of HRG-stimulated growth, some cell lines continue to respond to HRG. In cell lines where HRG-stimulated growth is lost, this loss is invariably accompanied by a reduction in ErbB3 levels, a corresponding increase in basal phosphorylation levels of FOXO-family transcription factors, and a reduction in HRG-induced downstream signaling. Importantly, HRG-stimulated growth is partially rescued by re-expressing ErbB3. This response is blocked by seribantumab, indicating that ErbB3 levels rather than downstream signaling proteins limit HRG-stimulated growth in PI3K mutant cells. Overall, these results suggest that activating mutations in PI3K do not preclude potential benefit from ErbB3-directed therapy, but that it may be important to measure ErbB3 levels in patients with PI3K mutant cancers to determine if they would benefit. PMID:26116360

  10. Sensing and Integration of Erk and PI3K Signals by Myc

    PubMed Central

    Lee, Tae; Yao, Guang; Nevins, Joseph; You, Lingchong

    2008-01-01

    The transcription factor Myc plays a central role in regulating cell-fate decisions, including proliferation, growth, and apoptosis. To maintain a normal cell physiology, it is critical that the control of Myc dynamics is precisely orchestrated. Recent studies suggest that such control of Myc can be achieved at the post-translational level via protein stability modulation. Myc is regulated by two Ras effector pathways: the extracellular signal-regulated kinase (Erk) and phosphatidylinositol 3-kinase (PI3K) pathways. To gain quantitative insight into Myc dynamics, we have developed a mathematical model to analyze post-translational regulation of Myc via sequential phosphorylation by Erk and PI3K. Our results suggest that Myc integrates Erk and PI3K signals to result in various cellular responses by differential stability control of Myc protein isoforms. Such signal integration confers a flexible dynamic range for the system output, governed by stability change. In addition, signal integration may require saturation of the input signals, leading to sensitive signal integration to the temporal features of the input signals, insensitive response to their amplitudes, and resistance to input fluctuations. We further propose that these characteristics of the protein stability control module in Myc may be commonly utilized in various cell types and classes of proteins. PMID:18463697

  11. PTEN and PI-3 kinase inhibitors control LPS signaling and the lymphoproliferative response in the CD19+ B cell compartment

    SciTech Connect

    Singh, Alok R.; Peirce, Susan K.; Joshi, Shweta; Durden, Donald L.

    2014-09-10

    Pattern recognition receptors (PRRs), e.g. toll receptors (TLRs) that bind ligands within the microbiome have been implicated in the pathogenesis of cancer. LPS is a ligand for two TLR family members, TLR4 and RP105 which mediate LPS signaling in B cell proliferation and migration. Although LPS/TLR/RP105 signaling is well-studied; our understanding of the underlying molecular mechanisms controlling these PRR signaling pathways remains incomplete. Previous studies have demonstrated a role for PTEN/PI-3K signaling in B cell selection and survival, however a role for PTEN/PI-3K in TLR4/RP105/LPS signaling in the B cell compartment has not been reported. Herein, we crossed a CD19cre and PTEN{sup fl/fl} mouse to generate a conditional PTEN knockout mouse in the CD19+ B cell compartment. These mice were further crossed with an IL-14α transgenic mouse to study the combined effect of PTEN deletion, PI-3K inhibition and expression of IL-14α (a cytokine originally identified as a B cell growth factor) in CD19+ B cell lymphoproliferation and response to LPS stimulation. Targeted deletion of PTEN and directed expression of IL-14α in the CD19+ B cell compartment (IL-14+PTEN-/-) lead to marked splenomegaly and altered spleen morphology at baseline due to expansion of marginal zone B cells, a phenotype that was exaggerated by treatment with the B cell mitogen and TLR4/RP105 ligand, LPS. Moreover, LPS stimulation of CD19+ cells isolated from these mice display increased proliferation, augmented AKT and NFκB activation as well as increased expression of c-myc and cyclinD1. Interestingly, treatment of LPS treated IL-14+PTEN-/- mice with a pan PI-3K inhibitor, SF1126, reduced splenomegaly, cell proliferation, c-myc and cyclin D1 expression in the CD19+ B cell compartment and normalized the splenic histopathologic architecture. These findings provide the direct evidence that PTEN and PI-3K inhibitors control TLR4/RP105/LPS signaling in the CD19+ B cell compartment and that pan PI

  12. Down-regulation of PKHD1 induces cell apoptosis through PI3K and NF-{kappa}B pathways

    SciTech Connect

    Sun, Liping; Wang, Shixuan; Hu, Chaofeng; Zhang, Xinzhou

    2011-04-15

    Mutations in PKHD1 (polycystic kidney and hepatic disease gene 1) gene cause the autosomal recessive polycystic kidney disease (ARPKD). Fibrocystin/polyductin (FPC), encoded by PKHD1, is a membrane-associated receptor-like protein. Although it is widely accepted that cystogenesis is mostly due to aberrant cell proliferation and apoptosis, it is still unclear how apoptosis is regulated. The aim of this study is to analyze the relationship among apoptosis, phosphatidylinositol 3-kinase (PI3K)/Akt and nuclear factor {kappa}B (NF-{kappa}B) in FPC knockdown kidney cells. We show that PKHD1-silenced HEK293 cells demonstrate a higher PI3K/Akt activity. Selective inhibition of PI3K/Akt using LY294002 or wortmannin in these cells increases serum starvation-induced HEK293 cell apoptosis with a concomitant decrease in cell proliferation and higher caspase-3 activity. PI3K/Akt inhibition also leads to increased NF-{kappa}B activity in these cells. We conclude that the PI3K/Akt pathway is involved in apoptotic function in PKHD1-silenced cells, and PI3K/Akt inhibition correlates with upregulation of NF-{kappa}B activity. These observations provide a potential platform for determining FPC function and therapeutic investigation of ARPKD.

  13. Regulation of the PI3-K/Akt survival pathway in the rat endometrium.

    PubMed

    Veillette, Annabelle; Grenier, Kathy; Brasseur, Kevin; Fréchette-Frigon, Guylaine; Leblanc, Valérie; Parent, Sophie; Asselin, Eric

    2013-03-01

    The occurrence of apoptosis and cell survival in the receptive uterus is intimately involved in the embryo implantation process in order to facilitate embryo attachment to the maternal endometrium. The initial stimulus leading to successful implantation might be triggered by the conceptus itself. By the end of rat embryo implantation, decidualization begins, followed by the regression of the decidua basalis on Day 14. The phosphatidylinositol 3-kinase (PI3-K) survival pathway and TGF-beta have been thought to play a role in this process. The objective of the present study was to investigate the regulation of the PI3-K/PTEN/Akt pathway in rat endometrium during pregnancy. Rats were killed on different days of pregnancy (Day 1-22 and postpartum) or pseudopregnancy (Day 1-9), and uteri were removed to collect endometrial tissues. The active form of Akt (pAkt) was increased at Day 5 of pregnancy and at Day 3 of pseudopregnancy as well as at Day 12 of pregnancy and at Day 1 postpartum. Of the three Akt isoforms (Akt1, Akt2, and Akt3), Akt3 was the only isoform phosphorylated at Day 5 during the implantation process and at postpartum as demonstrated by immunoprecipitation studies. PI3-K inhibition in vivo blocked Akt phosphorylation, reduced Smad2 phosphorylation, and reduced both TGF-beta2 and XIAP expression. PI3-K inhibition in cultured decidual cells led to inhibition of pAkt and decrease XIAP expression. These results suggest that Akt and XIAP may be important surviving signaling molecules by which apoptosis is regulated in the rat endometrium during pregnancy and that TGF-beta could be linked to this process.

  14. Apelin-13 impedes foam cell formation by activating Class III PI3K/Beclin-1-mediated autophagic pathway.

    PubMed

    Yao, Feng; Lv, Yun-Cheng; Zhang, Min; Xie, Wei; Tan, Yu-Lin; Gong, Duo; Cheng, Hai-Peng; Liu, Dan; Li, Liang; Liu, Xiao-Yan; Zheng, Xi-Long; Tang, Chao-Ke

    2015-10-30

    Apelin-13, an adipokine, promotes cholesterol efflux in macrophages with antiatherosclerotic effect. Autophagy, an evolutionarily ancient response to cellular stress, has been involved in atherosclerosis. Therefore, the purpose of this study was to investigate whether apelin-13 regulates macrophage foam cell cholesterol metabolism through autophagy, and also explore the underlying mechanisms. Here, we revealed that apelin-13 decreased lipid accumulation in THP-1 derived macrophages through markedly enhancing cholesterol efflux. Our study further demonstrated that apelin-13 induced autophagy via activation of Class III phosphoinositide 3-kinase (PI3K) and Beclin-1. Inhibition of Class III PI3K and Beclin-1 suppressed the stimulatory effects of apelin-13 on autophagy activity. The present study concluded that apelin-13 reduces lipid accumulation of foam cells by activating autophagy via Class III PI3K/Beclin-1 pathway. Therefore, our results provide brand new insight about apelin-13 inhibiting foam cell formation and highlight autophagy as a promising therapeutic target in atherosclerosis.

  15. Dual PI3K/mTOR inhibition is required to effectively impair microenvironment survival signals in mantle cell lymphoma

    PubMed Central

    Rosich, Laia; Montraveta, Arnau; Xargay-Torrent, Sílvia; López-Guerra, Mónica; Roldán, Jocabed; Aymerich, Marta; Salaverria, Itziar; Beà, Sílvia; Campo, Elías; Pérez-Galán, Patricia; Roué, Gaël; Colomer, Dolors

    2014-01-01

    Phosphatidylinositol-3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway activation contributes to mantle cell lymphoma (MCL) pathogenesis and drug resistance. Antitumor activity has been observed with mTOR inhibitors. However, they have shown limited clinical efficacy in relation to drug activation of feedback loops. Selective PI3K inhibition or dual PI3K/mTOR catalytic inhibition are different therapeutic approaches developed to achieve effective pathway blockage. Here, we have performed a comparative analysis of the mTOR inhibitor everolimus, the pan-PI3K inhibitor NVP-BKM120 and the dual PI3K/mTOR inhibitor NVP-BEZ235 in primary MCL cells. We found NVP-BEZ235 to be more powerful than everolimus or NVP-BKM120 in PI3K/Akt/mTOR signaling inhibition, indicating that targeting the PI3K/Akt/mTOR pathway at multiple levels is likely to be a more effective strategy for the treatment of MCL than single inhibition of these kinases. Among the three drugs, NVP-BEZ235 induced the highest change in gene expression profile. Functional validation demonstrated that NVP-BEZ235 inhibited angiogenesis, migration and tumor invasiveness in MCL cells. NVP-BEZ235 was the only drug able to block IL4 and IL6/STAT3 signaling which compromise the therapeutic effect of chemotherapy in MCL. Our findings support the use of the dual PI3K/mTOR inhibitor NVP-BEZ235 as a promising approach to interfere with the microenvironment-related processes in MCL. PMID:25216518

  16. Coenzyme Q10 restores amyloid beta-inhibited proliferation of neural stem cells by activating the PI3K pathway.

    PubMed

    Choi, Hojin; Park, Hyun-Hee; Lee, Kyu-Yong; Choi, Na-Young; Yu, Hyun-Jeung; Lee, Young Joo; Park, Jinse; Huh, Yong-Min; Lee, Sang-Hun; Koh, Seong-Ho

    2013-08-01

    Neurogenesis in the adult brain is important for memory and learning, and the alterations in neural stem cells (NSCs) may be an important part of Alzheimer's disease pathogenesis. The phosphatidylinositol 3-kinase (PI3K) pathway has been suggested to play an important role in neuronal cell survival and is highly involved in adult neurogenesis. Recently, coenzyme Q10 (CoQ10) was found to affect the PI3K pathway. We investigated whether CoQ10 could restore amyloid β (Aβ)25-35 oligomer-inhibited proliferation of NSCs by focusing on the PI3K pathway. To evaluate the effects of CoQ10 on Aβ25-35 oligomer-inhibited proliferation of NSCs, NSCs were treated with several concentrations of CoQ10 and/or Aβ25-35 oligomers. BrdU labeling, Colony Formation Assays, and immunoreactivity of Ki-67, a marker of proliferative activity, showed that NSC proliferation decreased with Aβ25-35 oligomer treatment, but combined treatment with CoQ10 restored it. Western blotting showed that CoQ10 treatment increased the expression levels of p85α PI3K, phosphorylated Akt (Ser473), phosphorylated glycogen synthase kinase-3β (Ser9), and heat shock transcription factor, which are proteins related to the PI3K pathway in Aβ25-35 oligomers-treated NSCs. To confirm a direct role for the PI3K pathway in CoQ10-induced restoration of proliferation of NSCs inhibited by Aβ25-35 oligomers, NSCs were pretreated with a PI3K inhibitor, LY294002; the effects of CoQ10 on the proliferation of NSCs inhibited by Aβ25-35 oligomers were almost completely blocked. Together, these results suggest that CoQ10 restores Aβ25-35 oligomer-inhibited proliferation of NSCs by activating the PI3K pathway.

  17. Vasculogenic Mimicry in Prostate Cancer: The Roles of EphA2 and PI3K

    PubMed Central

    Wang, Hua; Lin, Hao; Pan, Jincheng; Mo, Chengqiang; Zhang, Faming; Huang, Bin; Wang, Zongren; Chen, Xu; Zhuang, Jintao; Wang, Daohu; Qiu, Shaopeng

    2016-01-01

    BACKGROUND. Aggressive tumor cells can form perfusable networks that mimic normal vasculature and enhance tumor growth and metastasis. A number of molecular players have been implicated in such vasculogenic mimicry, among them the receptor tyrosine kinase EphA2, which is aberrantly expressed in aggressive tumors. Here we study the role and regulation of EphA2 in vasculogenic mimicry in prostate cancer where this phenomenon is still poorly understood. METHODS. Vasculogenic mimicry was characterized by tubules whose cellular lining was negative for the endothelial cell marker CD34 but positive for periodic acid-Schiff staining, and/or contained red blood cells. Vasculogenic mimicry was assessed in 92 clinical samples of prostate cancer and analyzed in more detail in three prostate cancer cell lines kept in three-dimensional culture. Tissue samples and cell lines were also assessed for total and phosphorylated levels of EphA2 and its potential regulator, Phosphoinositide 3-Kinase (PI3K). In addition, the role of EphA2 in vasculogenic mimicry and in cell migration and invasion were investigated by manipulating the levels of EphA2 through specific siRNAs. Furthermore, the role of PI3K in vasculogenic mimicry and in regulating EphA2 was tested by application of an inhibitor, LY294002. RESULTS. Immunohistochemistry of prostate cancers showed a significant correlation between vasculogenic mimicry and high expression levels of EphA2, high Gleason scores, advanced TNM stage, and the presence of lymph node and distant metastases. Likewise, two prostate cancer cell lines (PC3 and DU-145) formed vasculogenic networks on Matrigel and expressed high EphA2 levels, while one line (LNCaP) showed no vasculogenic networks and lower EphA2 levels. Specific silencing of EphA2 in PC3 and DU-145 cells decreased vasculogenic mimicry as well as cell migration and invasion. Furthermore, high expression levels of PI3K and EphA2 phosphorylation at Ser897 significantly correlated with the

  18. TDRG1 functions in testicular seminoma are dependent on the PI3K/Akt/mTOR signaling pathway

    PubMed Central

    Wang, Yong; Gan, Yu; Tan, Zhengyu; Zhou, Jun; Kitazawa, Riko; Jiang, Xianzhen; Tang, Yuxin; Yang, Jianfu

    2016-01-01

    Human testis development-related gene 1 (TDRG1) is a recently identified gene that is expressed exclusively in the testes and promotes the development of testicular germ cell tumors. In this study, the role of TDRG1 in the development of testicular seminoma, which is the most common testicular germ cell tumor, was further investigated. Based on polymerase chain reaction, Western blotting, and immunohistochemistry tests, both gene and protein expression levels of TDRG1 were significantly upregulated in testicular seminoma tissues compared with normal testicular tissues. Additionally, the levels of phosphoinositide-3 kinase (PI3K)/p110 and Akt phosphorylation were dramatically upregulated in testicular seminoma tissues. Accordingly, in our cell experiment, seminoma TCam-2 cells were subjected to different treatments: the TDRG1 knockout, TDRG1 overexpression, PI3K inhibition (LY294002 administration), or PI3K activation (insulin-like growth factor-1 administration). Cell proliferation, the proliferation index, apoptosis rate, cell adhesive capacity, and cell invasion capability were assessed. Cells with both TDRG1 knockout and PI3K inhibition exhibited decreased cell proliferation, proliferation indexes, cell adhesion capacity, and cell invasion capability and increased apoptosis rates. Most of these effects were reversed by TDRG1 overexpression or PI3K activation, indicating that both TDRG1- and PI3K-mediated signaling promote proliferation and invasion of testicular seminoma cells. The knockout of TDRG1 significantly decreased the phosphorylation levels of PI3K/p85, PI3K/p110, Akt, and mammalian target of rapamycin (mTOR; Ser2448). Except for PI3K/p110, TDRG1 overexpression had the opposite effects on phosphorylation levels. Phosphorylated mTOR at Ser2481 and Thr2446 was not affected by TDRG1 or PI3K in our tests. Thus, these results indicate that TDRG1 promotes the development and migration of seminoma cells via the regulation of the PI3K/Akt/mTOR signaling pathway

  19. PI3K/Akt activity has variable cell-specific effects on expression of HIF target genes, CA9 and VEGF, in human cancer cell lines.

    PubMed

    Shafee, Norazizah; Kaluz, Stefan; Ru, Ning; Stanbridge, Eric J

    2009-09-01

    The phosphatidylinositol 3-kinase/Akt (PI3K) pathway regulates hypoxia-inducible factor (HIF) activity. Higher expression of HIF-1alpha and carbonic anhydrase IX (CAIX), a hypoxia-inducible gene, in HT10806TG fibrosarcoma cells (mutant N-ras allele), compared to derivative MCH603 cells (deleted mutant N-ras allele), correlated with increased PI3K activity. Constitutive activation of the PI3K pathway in MCH603/PI3K(act) cells increased HIF-1alpha but, surprisingly, decreased CAIX levels. The cell-type specific inhibitory effect on CAIX was confirmed at the transcriptional level whereas epigenetic modifications of CA9 were ruled out. In summary, our data do not substantiate the generalization that PI3K upregulation leads to increased HIF activity. PMID:19342157

  20. Delphinidin suppresses ultraviolet B-induced cyclooxygenases-2 expression through inhibition of MAPKK4 and PI-3 kinase.

    PubMed

    Kwon, Jung Yeon; Lee, Ki Won; Kim, Jong-Eun; Jung, Sung Keun; Kang, Nam Joo; Hwang, Mun Kyung; Heo, Yong-Seok; Bode, Ann M; Dong, Zigang; Lee, Hyong Joo

    2009-11-01

    Cyclooxygenase-2 (COX-2), a key mediator of inflammation, and its product, prostaglandin E(2) (PGE(2)), enhance carcinogenesis, particularly in skin. Ultraviolet (UV) B is the most carcinogenic component of solar irradiation, and a crucial role of COX-2 in UVB-mediated skin carcinogenesis has been reported. Here, we investigated the effects of delphinidin, an abundant dietary anthocyanin, on UVB-induced COX-2 upregulation and the underlying molecular mechanism. We found that delphinidin suppressed UVB-induced COX-2 expression in JB6 P+ mouse epidermal cells. COX-2 promoter activity and PGE(2) production were also suppressed by delphinidin treatment within non-cytotoxic concentrations. Activator protein-1 and nuclear factor-kappaB, crucial transcription factors involved in COX-2 expression, were activated by UVB and delphinidin abolished this activation. UVB-induced phosphorylation of c-Jun N-terminal kinase, p38 kinase and Akt was inhibited by delphinidin. The activities of mitogen-activated protein kinase kinase (MAPKK) 4 and phosphatidylinositol-3 kinase (PI-3K) were inhibited markedly by delphinidin. A pull-down assay using delphinidin-Sepharose beads revealed that delphinidin binds directly with MAPKK4 or PI-3K in a manner that was competitive with adenosine triphosphate. Moreover, in vivo investigations using mouse skin revealed that the upregulation of COX-2 expression, MAPKK4 activity and PI-3K activity induced by UVB was abolished with delphinidin treatment. Collectively, our results demonstrated that delphinidin targets MAPKK4 and PI-3K directly to suppress COX-2 overexpression, suggesting a potential protective role for delphinidin against UVB-mediated skin carcinogenesis.

  1. Activation of PI3-kinase stimulates endocytosis of ROMK via Akt1/SGK1-dependent phosphorylation of WNK1.

    PubMed

    Cheng, Chih-Jen; Huang, Chou-Long

    2011-03-01

    WNK kinases stimulate endocytosis of ROMK channels to regulate renal K+ handling. Phosphatidylinositol 3-kinase (PI3K)-activating hormones, such as insulin and IGF 1, phosphorylate WNK1, but how this affects the regulation of ROMK abundance is unknown. Here, serum starvation of ROMK-transfected HEK cells led to an increase of ROMK current density; subsequent addition of insulin or IGF1 inhibited ROMK currents in a PI3K-dependent manner. Serum and insulin also increased phosphorylation of the downstream kinases Akt1 and SGK1 as well as WNK1. A biotinylation assay suggested that insulin and IGF1 inhibit ROMK by enhancing its endocytosis, a process that WNK1 may mediate. Knockdown of WNK1 with siRNA or expression of a phospho-deficient WNK1 mutant (T58A) both prevented insulin-induced inhibition of ROMK currents, suggesting that phosphorylation at Threonine-58 of WNK1 is important to mediate the inhibition of ROMK by PI3K-activating hormones or growth factors. In vitro and in vivo kinase assays supported the notion that Akt1 and SGK1 can phosphorylate WNK1 at this site, and we established that Akt1 and SGK1 synergistically inhibit ROMK through WNK1. We used dominant-negative intersectin and dynamin constructs to show that SGK1-mediated phosphorylation of WNK1 inhibits ROMK by promoting its endocytosis. Taken together, these results suggest that PI3K-activating hormones inhibit ROMK by enhancing its endocytosis via a mechanism that involves phosphorylation of WNK1 by Akt1 and SGK1. PMID:21355052

  2. PI3K-GSK3 signalling regulates mammalian axon regeneration by inducing the expression of Smad1

    NASA Astrophysics Data System (ADS)

    Saijilafu; Hur, Eun-Mi; Liu, Chang-Mei; Jiao, Zhongxian; Xu, Wen-Lin; Zhou, Feng-Quan

    2013-10-01

    In contrast to neurons in the central nervous system, mature neurons in the mammalian peripheral nervous system (PNS) can regenerate axons after injury, in part, by enhancing intrinsic growth competence. However, the signalling pathways that enhance the growth potential and induce spontaneous axon regeneration remain poorly understood. Here we reveal that phosphatidylinositol 3-kinase (PI3K) signalling is activated in response to peripheral axotomy and that PI3K pathway is required for sensory axon regeneration. Moreover, we show that glycogen synthase kinase 3 (GSK3), rather than mammalian target of rapamycin, mediates PI3K-dependent augmentation of the growth potential in the PNS. Furthermore, we show that PI3K-GSK3 signal is conveyed by the induction of a transcription factor Smad1 and that acute depletion of Smad1 in adult mice prevents axon regeneration in vivo. Together, these results suggest PI3K-GSK3-Smad1 signalling as a central module for promoting sensory axon regeneration in the mammalian nervous system.

  3. Amoebic PI3K and PKC is required for Jurkat T cell death induced by Entamoeba histolytica.

    PubMed

    Lee, Young Ah; Kim, Kyeong Ah; Min, Arim; Shin, Myeong Heon

    2014-08-01

    The enteric protozoan parasite Entamoeba histolytica is the causative agent of human amebiasis. During infection, adherence of E. histolytica through Gal/GalNAc lectin on the surface of the amoeba can induce caspase-3-dependent or -independent host cell death. Phosphorylinositol 3-kinase (PI3K) and protein kinase C (PKC) in E. histolytica play an important function in the adhesion, killing, or phagocytosis of target cells. In this study, we examined the role of amoebic PI3K and PKC in amoeba-induced apoptotic cell death in Jurkat T cells. When Jurkat T cells were incubated with E. histolytica trophozoites, phosphatidylserine (PS) externalization and DNA fragmentation in Jurkat cells were markedly increased compared to those of cells incubated with medium alone. However, when amoebae were pretreated with a PI3K inhibitor, wortmannin before being incubated with E. histolytica, E. histolytica-induced PS externalization and DNA fragmentation in Jurkat cells were significantly reduced compared to results for amoebae pretreated with DMSO. In addition, pretreatment of amoebae with a PKC inhibitor, staurosporine strongly inhibited Jurkat T cell death. However, E. histolytica-induced cleavage of caspase-3, -6, and -7 were not inhibited by pretreatment of amoebae with wortmannin or staurosporin. In addition, we found that amoebic PI3K and PKC have an important role on amoeba adhesion to host compartment. These results suggest that amebic PI3K and PKC activation may play an important role in caspase-independent cell death in Entamoeba-induced apoptosis.

  4. Amoebic PI3K and PKC is required for Jurkat T cell death induced by Entamoeba histolytica.

    PubMed

    Lee, Young Ah; Kim, Kyeong Ah; Min, Arim; Shin, Myeong Heon

    2014-08-01

    The enteric protozoan parasite Entamoeba histolytica is the causative agent of human amebiasis. During infection, adherence of E. histolytica through Gal/GalNAc lectin on the surface of the amoeba can induce caspase-3-dependent or -independent host cell death. Phosphorylinositol 3-kinase (PI3K) and protein kinase C (PKC) in E. histolytica play an important function in the adhesion, killing, or phagocytosis of target cells. In this study, we examined the role of amoebic PI3K and PKC in amoeba-induced apoptotic cell death in Jurkat T cells. When Jurkat T cells were incubated with E. histolytica trophozoites, phosphatidylserine (PS) externalization and DNA fragmentation in Jurkat cells were markedly increased compared to those of cells incubated with medium alone. However, when amoebae were pretreated with a PI3K inhibitor, wortmannin before being incubated with E. histolytica, E. histolytica-induced PS externalization and DNA fragmentation in Jurkat cells were significantly reduced compared to results for amoebae pretreated with DMSO. In addition, pretreatment of amoebae with a PKC inhibitor, staurosporine strongly inhibited Jurkat T cell death. However, E. histolytica-induced cleavage of caspase-3, -6, and -7 were not inhibited by pretreatment of amoebae with wortmannin or staurosporin. In addition, we found that amoebic PI3K and PKC have an important role on amoeba adhesion to host compartment. These results suggest that amebic PI3K and PKC activation may play an important role in caspase-independent cell death in Entamoeba-induced apoptosis. PMID:25246714

  5. Will targeting PI3K/Akt/mTOR signaling work in hematopoietic malignancies?

    PubMed Central

    Gao, Yanan; Yuan, Chase Y.

    2016-01-01

    The constitutive activation of phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) signaling pathway has been demonstrated to be critical in clinical cancer patients as well as in laboratory cancer models including hematological malignancies. Great efforts have been made to develop inhibitors targeting this pathway in hematological malignancies but so far the efficacies of these inhibitors were not as good as expected. By analyzing existing literatures and datasets available, we found that mutations of genes in the pathway only constitute a very small subset of hematological malignancies. Deep understanding of the function of gene, the pathway and/or its regulators, and the cellular response to inhibitors, may help us design better drugs targeting the hematological malignancies. PMID:27583254

  6. Biochemical, biological and structural properties of romidepsin (FK228) and its analogs as novel HDAC/PI3K dual inhibitors.

    PubMed

    Saijo, Ken; Imamura, Jin; Narita, Koichi; Oda, Akifumi; Shimodaira, Hideki; Katoh, Tadashi; Ishioka, Chikashi

    2015-02-01

    Romidepsin (FK228, depsipeptide) is a potent histone deacetylase (HDAC) inhibitor that has FDA approval for the treatment of cutaneous and peripheral T-cell lymphomas. We have previously reported that FK228 and its analogs have an additional activity as phosphatidylinositol 3-kinase (PI3K) inhibitors, and are defined as HDAC/PI3K dual inhibitors. Because a combination of an HDAC inhibitor and a PI3K inhibitor induces apoptosis in human cancer cells in a synergistic manner, development of an HDAC/PI3K dual inhibitor will provide an attractive novel drug for cancer therapy. Using structure-based optimization of the analogs, FK-A11 was identified as the most potent analog. FK-A11 inhibited phosphorylation of AKT and accelerated histone acetylation at lower concentrations, resulting in stronger cytotoxic effects than FK228 and the other analogs in human cancer cells. In this study, we have characterized the biochemical, biological and structural properties of FK228 analogs as PI3K inhibitors. First, FK-A11 is an ATP competitive PI3K inhibitor. Second, FK-A11 is a pan-p110 isoform inhibitor. Third, FK-A11 selectively inhibits PI3K among 22 common cellular kinases. Fourth, conformational changes of FK228 analogs by reduction of an internal disulfide bond have no effect on PI3K inhibitory activity, unlike HDAC inhibitory activity. Finally, molecular modeling of PI3K-FK228 analogs and analyses of the binding affinities identified the structure that defines potency for PI3K inhibitory activity. These results prove our concept that a series of FK228 analogs are HDAC/PI3K dual inhibitors. These findings should help in the development of FK228 analogs as novel HDAC/PI3K dual inhibitors.

  7. PI3K: An Attractive Candidate for the Central Integration of Metabolism and Reproduction

    PubMed Central

    Acosta-Martínez, Maricedes

    2012-01-01

    In neurons, as in a variety of other cell types, the enzyme phosphatidylinositol-3-kinase (PI3K) is a key intermediate that is common to the signaling pathways of a number of peripheral metabolic cues, including insulin and leptin, which are well known to regulate both metabolic and reproductive functions. This review article will explore the possibility that PI3K is a key integrator of metabolic and neural signals regulating gonadotropin releasing hormone (GnRH)/luteinizing hormone (LH) release and explore the hypothesis that this enzyme is pivotal in many disorders where gonadotropin release is at risk. Although the mechanisms mediating the influence of metabolism and nutrition on fertility are currently unclear, the strong association between metabolic disorders and infertility is undeniable. For example, women suffering from anorectic disorders experience amenorrhea as a consequence of malnutrition-induced impairment of LH release, and at the other extreme, obesity is also commonly co-morbid with menstrual dysfunction and infertility. Impaired hypothalamic insulin and leptin receptor signaling is thought to be at the core of reproductive disorders associated with metabolic dysfunction. While low levels of leptin and insulin characterize states of negative energy balance, prolonged nutrient excess is associated with insulin and leptin resistance. Metabolic models known to alter GnRH/LH release such as diabetes, diet-induced obesity, and caloric restriction are also accompanied by impairment of PI3K signaling in insulin and leptin sensitive tissues including the hypothalamus. However, a clear link between this signaling pathway and the control of GnRH release by peripheral metabolic cues has not been established. Investigating the role of the signaling pathways shared by metabolic cues that are critical for a normal reproductive state can help identify possible targets in the treatment of metabolic and reproductive disorders such as polycystic ovarian syndrome

  8. Integrin β1 mediates vaccinia virus entry through activation of PI3K/Akt signaling.

    PubMed

    Izmailyan, Roza; Hsao, Jye-Chian; Chung, Che-Sheng; Chen, Chein-Hung; Hsu, Paul Wei-Che; Liao, Chung-Lin; Chang, Wen

    2012-06-01

    Vaccinia virus has a broad range of infectivity in many cell lines and animals. Although it is known that the vaccinia mature virus binds to cell surface glycosaminoglycans and extracellular matrix proteins, whether additional cellular receptors are required for virus entry remains unclear. Our previous studies showed that the vaccinia mature virus enters through lipid rafts, suggesting the involvement of raft-associated cellular proteins. Here we demonstrate that one lipid raft-associated protein, integrin β1, is important for vaccinia mature virus entry into HeLa cells. Vaccinia virus associates with integrin β1 in lipid rafts on the cell surface, and the knockdown of integrin β1 in HeLa cells reduces vaccinia mature virus entry. Additionally, vaccinia mature virus infection is reduced in a mouse cell line, GD25, that is deficient in integrin β1 expression. Vaccinia mature virus infection triggers the activation of phosphatidylinositol 3-kinase (PI3K)/Akt signaling, and the treatment of cells with inhibitors to block P13K activation reduces virus entry in an integrin β1-dependent manner, suggesting that integrin β1-mediates PI3K/Akt activation induced by vaccinia virus and that this signaling pathway is essential for virus endocytosis. The inhibition of integrin β1-mediated cell adhesion results in a reduction of vaccinia virus entry and the disruption of focal adhesion and PI3K/Akt activation. In summary, our results show that the binding of vaccinia mature virus to cells mimics the outside-in activation process of integrin functions to facilitate vaccinia virus entry into HeLa cells.

  9. Ursolic Acid Increases Glucose Uptake through the PI3K Signaling Pathway in Adipocytes

    PubMed Central

    He, Yonghan; Li, Wen; Li, Ying; Zhang, Shuocheng; Wang, Yanwen; Sun, Changhao

    2014-01-01

    Background Ursolic acid (UA), a triterpenoid compound, is reported to have a glucose-lowering effect. However, the mechanisms are not fully understood. Adipose tissue is one of peripheral tissues that collectively control the circulating glucose levels. Objective The objective of the present study was to determine the effect and further the mechanism of action of UA in adipocytes. Methods and Results The 3T3-L1 preadipocytes were induced to differentiate and treated with different concentrations of UA. NBD-fluorescent glucose was used as the tracer to measure glucose uptake and Western blotting used to determine the expression and activity of proteins involved in glucose transport. It was found that 2.5, 5 and 10 µM of UA promoted glucose uptake in a dose-dependent manner (17%, 29% and 35%, respectively). 10 µM UA-induced glucose uptake with insulin stimulation was completely blocked by the phosphatidylinositol (PI) 3-kinase (PI3K) inhibitor wortmannin (1 µM), but not by SB203580 (10 µM), the inhibitor of mitogen-activated protein kinase (MAPK), or compound C (2.5 µM), the inhibitor of AMP-activated kinase (AMPK) inhibitor. Furthmore, the downstream protein activities of the PI3K pathway, phosphoinositide-dependent kinase (PDK) and phosphoinositide-dependent serine/threoninekinase (AKT) were increased by 10 µM of UA in the presence of insulin. Interestingly, the activity of AS160 and protein kinase C (PKC) and the expression of glucose transporter 4 (GLUT4) were stimulated by 10 µM of UA under either the basal or insulin-stimulated status. Moreover, the translocation of GLUT4 from cytoplasm to cell membrane was increased by UA but decreased when the PI3K inhibitor was applied. Conclusions Our results suggest that UA stimulates glucose uptake in 3T3-L1 adipocytes through the PI3K pathway, providing important information regarding the mechanism of action of UA for its anti-diabetic effect. PMID:25329874

  10. Ribonuclease 5 facilitates corneal endothelial wound healing via activation of PI3-kinase/Akt pathway

    PubMed Central

    Kim, Kyoung Woo; Park, Soo Hyun; Lee, Soo Jin; Kim, Jae Chan

    2016-01-01

    To maintain corneal transparency, corneal endothelial cells (CECs) exert a pump function against aqueous inflow. However, human CECs are arrested in the G1-phase and non-proliferative in vivo. Thus, treatment of corneal endothelial decompensation is limited to corneal transplantation, and grafts are vulnerable to immune rejection. Here, we show that ribonuclease (RNase) 5 is more highly expressed in normal human CECs compared to decompensated tissues. Furthermore, RNase 5 up-regulated survival of CECs and accelerated corneal endothelial wound healing in an in vitro wound of human CECs and an in vivo cryo-damaged rabbit model. RNase 5 treatment rapidly induced accumulation of cytoplasmic RNase 5 into the nucleus, and activated PI3-kinase/Akt pathway in human CECs. Moreover, inhibition of nuclear translocation of RNase 5 using neomycin reversed RNase 5-induced Akt activation. As a potential strategy for proliferation enhancement, RNase 5 increased the population of 5-bromo-2′-deoxyuridine (BrdU)-incorporated proliferating CECs with concomitant PI3-kinase/Akt activation, especially in CECs deprived of contact-inhibition. Specifically, RNase 5 suppressed p27 and up-regulated cyclin D1, D3, and E by activating PI3-kinase/Akt in CECs to initiate cell cycle progression. Together, our data indicate that RNase 5 facilitates corneal endothelial wound healing, and identify RNase 5 as a novel target for therapeutic exploitation. PMID:27526633

  11. Investigating the role of class-IA PI 3-kinase isoforms in adipocyte differentiation

    SciTech Connect

    Kim, Ji Eun; Shepherd, Peter R. Chaussade, Claire

    2009-02-20

    PI 3-kinases, in particular class-IA, are key signalling molecules controlling many cellular processes including growth, proliferation, migration and differentiation. In this study, we have used a collection of isoform selective PI 3-kinase inhibitors to determine whether attenuation of signalling through class-IA PI 3-kinase isoforms will impact adipocyte differentiation. First, we analysed the expression profiles and found that fibroblastic pre-adipocytes express detectable levels of p110{alpha} and p110{delta} and that after differentiation, p110{delta} levels fall while p110{alpha} levels rise, together with C/EBP{alpha} and PPAR{gamma}. When using specific inhibitors during the differentiation process, we observed that neither p110{beta} nor p110{delta} inhibition, had any significant effect. In contrast PIK-75, a selective p110{alpha} inhibitor completely abolished adipocyte differentiation as assessed by morphology, transcript and protein levels of adipocyte markers. These results indicate that long term treatment with p110{alpha} inhibitors could potentially have a severe impact on fat cell numbers in vivo.

  12. PI3K-C2γ is a Rab5 effector selectively controlling endosomal Akt2 activation downstream of insulin signalling

    PubMed Central

    Braccini, Laura; Ciraolo, Elisa; Campa, Carlo C.; Perino, Alessia; Longo, Dario L.; Tibolla, Gianpaolo; Pregnolato, Marco; Cao, Yanyan; Tassone, Beatrice; Damilano, Federico; Laffargue, Muriel; Calautti, Enzo; Falasca, Marco; Norata, Giuseppe D.; Backer, Jonathan M.; Hirsch, Emilio

    2015-01-01

    In the liver, insulin-mediated activation of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway is at the core of metabolic control. Multiple PI3K and Akt isoenzymes are found in hepatocytes and whether isoform-selective interplays exist is currently unclear. Here we report that insulin signalling triggers the association of the liver-specific class II PI3K isoform γ (PI3K-C2γ) with Rab5-GTP, and its recruitment to Rab5-positive early endosomes. In these vesicles, PI3K-C2γ produces a phosphatidylinositol-3,4-bisphosphate pool specifically required for delayed and sustained endosomal Akt2 stimulation. Accordingly, loss of PI3K-C2γ does not affect insulin-dependent Akt1 activation as well as S6K and FoxO1-3 phosphorylation, but selectively reduces Akt2 activation, which specifically inhibits glycogen synthase activity. As a consequence, PI3K-C2γ-deficient mice display severely reduced liver accumulation of glycogen and develop hyperlipidemia, adiposity as well as insulin resistance with age or after consumption of a high-fat diet. Our data indicate PI3K-C2γ supports an isoenzyme-specific forking of insulin-mediated signal transduction to an endosomal pool of Akt2, required for glucose homeostasis. PMID:26100075

  13. BMX acts downstream of PI3K to promote colorectal cancer cell survival and pathway inhibition sensitizes to the BH3 mimetic ABT-737.

    PubMed

    Potter, Danielle S; Kelly, Paul; Denneny, Olive; Juvin, Veronique; Stephens, Len R; Dive, Caroline; Morrow, Christopher J

    2014-02-01

    Evasion of apoptosis is a hallmark of cancer, and reversing this process by inhibition of survival signaling pathways is a potential therapeutic strategy. Phosphoinositide 3-kinase (PI3K) signaling can promote cell survival and is upregulated in solid tumor types, including colorectal cancer (CRC), although these effects are context dependent. The role of PI3K in tumorigenesis combined with their amenability to specific inhibition makes them attractive drug targets. However, we observed that inhibition of PI3K in HCT116, DLD-1, and SW620 CRC cells did not induce apoptotic cell death. Moreover, these cells were relatively resistant to the Bcl-2 homology domain 3 (BH3) mimetic ABT-737, which directly targets the Bcl-2 family of apoptosis regulators. To test the hypothesis that PI3K inhibition lowers the apoptotic threshold without causing apoptosis per se, PI3K inhibitors were combined with ABT-737. PI3K inhibition enhanced ABT-737-induced apoptosis by 2.3- to 4.5-fold and reduced expression levels of MCL-1, the resistance biomarker for ABT-737. PI3K inhibition enhanced ABT-737-induced apoptosis a further 1.4- to 2.4-fold in CRC cells with small interfering RNA-depleted MCL-1, indicative of additional sensitizing mechanisms. The observation that ABT-737-induced apoptosis was unaffected by inhibition of PI3K downstream effectors AKT and mTOR, implicated a novel PI3K-dependant pathway. To elucidate this, an RNA interference (RNAi) screen of potential downstream effectors of PI3K signaling was conducted, which demonstrated that knockdown of the TEC kinase BMX sensitized to ABT-737. This suggests that BMX is an antiapoptotic downstream effector of PI3K, independent of AKT. PMID:24709422

  14. PI3 Kinase Pathway and MET Inhibition is Efficacious in Malignant Pleural Mesothelioma.

    PubMed

    Kanteti, Rajani; Riehm, Jacob J; Dhanasingh, Immanuel; Lennon, Frances E; Mirzapoiazova, Tamara; Mambetsariev, Bolot; Kindler, Hedy L; Salgia, Ravi

    2016-01-01

    Malignant pleural mesothelioma (MPM) is an aggressive cancer that is commonly associated with prior asbestos exposure. Receptor tyrosine kinases (RTKs) such as MET and its downstream target PI3K are overexpressed and activated in a majority of MPMs. Here, we studied the combinatorial therapeutic efficacy of the MET/ALK inhibitor crizotinib, with either a pan-class I PI3K inhibitor, BKM120, or with a PI3K/mTOR dual inhibitor, GDC-0980, in mesothelioma. Cell viability results showed that MPM cells were highly sensitive to crizotinib, BKM120 and GDC-0980 when used individually and their combination was more effective in suppressing growth. Treatment of MPM cells with these inhibitors also significantly decreased cell migration, and the combination of them was synergistic. Treatment with BKM120 alone or in combination with crizotinib induced G2-M arrest and apoptosis. Both crizotinib and BKM120 strongly inhibited the activity of MET and PI3K as evidenced by the decreased phosphorylation of MET, AKT and ribosomal S6 kinase. Using a PDX mouse model, we showed that a combination of crizotinib with BKM120 was highly synergetic in inhibiting MPM tumor growth. In conclusion our findings suggest that dual inhibition of PI3K and MET pathway is an effective strategy in treating MPM as compared to a single agent. PMID:27623107

  15. PI3 Kinase Pathway and MET Inhibition is Efficacious in Malignant Pleural Mesothelioma

    PubMed Central

    Kanteti, Rajani; Riehm, Jacob J.; Dhanasingh, Immanuel; Lennon, Frances E.; Mirzapoiazova, Tamara; Mambetsariev, Bolot; Kindler, Hedy L.; Salgia, Ravi

    2016-01-01

    Malignant pleural mesothelioma (MPM) is an aggressive cancer that is commonly associated with prior asbestos exposure. Receptor tyrosine kinases (RTKs) such as MET and its downstream target PI3K are overexpressed and activated in a majority of MPMs. Here, we studied the combinatorial therapeutic efficacy of the MET/ALK inhibitor crizotinib, with either a pan-class I PI3K inhibitor, BKM120, or with a PI3K/mTOR dual inhibitor, GDC-0980, in mesothelioma. Cell viability results showed that MPM cells were highly sensitive to crizotinib, BKM120 and GDC-0980 when used individually and their combination was more effective in suppressing growth. Treatment of MPM cells with these inhibitors also significantly decreased cell migration, and the combination of them was synergistic. Treatment with BKM120 alone or in combination with crizotinib induced G2-M arrest and apoptosis. Both crizotinib and BKM120 strongly inhibited the activity of MET and PI3K as evidenced by the decreased phosphorylation of MET, AKT and ribosomal S6 kinase. Using a PDX mouse model, we showed that a combination of crizotinib with BKM120 was highly synergetic in inhibiting MPM tumor growth. In conclusion our findings suggest that dual inhibition of PI3K and MET pathway is an effective strategy in treating MPM as compared to a single agent. PMID:27623107

  16. Follistatin could promote the proliferation of duck primary myoblasts by activating PI3K/Akt/mTOR signalling

    PubMed Central

    Li, Xinxin; Liu, Hehe; Wang, Haohan; Sun, Lingli; Ding, Fang; Sun, Wenqiang; Han, Chunchun; Wang, Jiwen

    2014-01-01

    FST (follistatin) is essential for skeletal muscle development, but the intracellular signalling networks that regulate FST-induced effects are not well defined. We sought to investigate whether FST promotes the proliferation of myoblasts through the PI3K (phosphoinositide 3-kinase)/Akt (protein kinase B)/mTOR (mammalian target of rapamycin) signalling. In the present study, we transfected the pEGFP-duFST plasmid and added PI3K and mTOR inhibitors to the medium of duck primary myoblasts. Then, we analysed the cellular phenotypic changes that occurred and analysed the expression of target genes. The results showed that FST promoted myoblast proliferation, induced the mRNA expression of PI3K, Akt, mTOR, 70-kDa ribosomal protein S6K (S6 kinase) and the protein expression of phospho-Akt (Thr308), mTOR, phospho-mTOR (serine 2448), phospho-S6K (Ser417), inhibited the mRNA expression of FoxO1, MuRF1 (muscle RING finger-1) and the protein expression of phospho-FoxO1 (Ser256). Moreover, we found that the overexpression of FST could alleviate the inhibitory effect of myoblast proliferation caused by the addition of LY294002, a PI3K inhibitor. Additionally, the overexpression of duck FST also relieved the inhibition of myoblast proliferation caused by the addition of rapamycin (an mTOR inhibitor) through PI3K/Akt/mTOR signalling. In light of the present results, we hypothesize that duck FST could promote myoblast proliferation, which is dependent on PI3K/Akt/mTOR signalling. PMID:25200144

  17. Dual targeting of the PI3K/Akt/mTOR pathway as an antitumor strategy in Waldenstrom macroglobulinemia

    PubMed Central

    Roccaro, Aldo M.; Sacco, Antonio; Husu, Emanuel N.; Pitsillides, Costas; Vesole, Steven; Azab, Abdel Kareem; Azab, Feda; Melhem, Molly; Ngo, Hai T.; Quang, Phong; Maiso, Patricia; Runnels, Judith; Liang, Mei-Chih; Wong, Kwok-Kin; Lin, Charles

    2010-01-01

    We have previously shown clinical activity of a mammalian target of rapamycin (mTOR) complex 1 inhibitor in Waldenstrom macroglobulinemia (WM). However, 50% of patients did not respond to therapy. We therefore examined mechanisms of activation of the phosphoinositide 3-kinase (PI3K)/Akt/mTOR in WM, and mechanisms of overcoming resistance to therapy. We first demonstrated that primary WM cells show constitutive activation of the PI3K/Akt pathway, supported by decreased expression of phosphate and tensin homolog tumor suppressor gene (PTEN) at the gene and protein levels, together with constitutive activation of Akt and mTOR. We illustrated that dual targeting of the PI3K/mTOR pathway by the novel inhibitor NVP-BEZ235 showed higher cytotoxicity on WM cells compared with inhibition of the PI3K or mTOR pathways alone. In addition, NVP-BEZ235 inhibited both rictor and raptor, thus abrogating the rictor-induced Akt phosphorylation. NVP-BEZ235 also induced significant cytotoxicity in WM cells in a caspase-dependent and -independent manner, through targeting the Forkhead box transcription factors. In addition, NVP-BEZ235 targeted WM cells in the context of bone marrow microenvironment, leading to significant inhibition of migration, adhesion in vitro, and homing in vivo. These studies therefore show that dual targeting of the PI3K/mTOR pathway is a better modality of targeted therapy for tumors that harbor activation of the PI3K/mTOR signaling cascade, such as WM. PMID:19965685

  18. PTEN regulates angiogenesis through PI3K/Akt/VEGF signaling pathway in human pancreatic cancer cells.

    PubMed

    Ma, Jiachi; Sawai, Hirozumi; Ochi, Nobuo; Matsuo, Yoichi; Xu, Donghui; Yasuda, Akira; Takahashi, Hiroki; Wakasugi, Takehiro; Takeyama, Hiromitsu

    2009-11-01

    Phosphoinositide 3-kinase (PI3K) pathway exerts its effects through Akt, its downstream target molecule, and thereby regulates various cell functions including cell proliferation, cell transformation, apoptosis, tumor growth, and angiogenesis. Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) has been implicated in regulating cell survival signaling through the PI3K/Akt pathway. However, the mechanism by PI3K/PTEN signaling regulates angiogenesis and tumor growth in vivo remains to be elucidated. Vascular endothelial growth factor (VEGF) plays a pivotal role in tumor angiogenesis. The effect of PTEN on VEGF-mediated signal in pancreatic cancer is unknown. This study aimed to determine the effect of PTEN on both the expression of VEGF and angiogenesis. Toward that end, we used the siRNA knockdown method to specifically define the role of PTEN in the expression of VEGF and angiogenesis. We found that siRNA-mediated inhibition of PTEN gene expression in pancreatic cancer cells increase their VEGF secretion, up-modulated the proliferation, and migration of co-cultured vascular endothelial cell and enhanced tubule formation by HUVEC. In addition, PTEN modulated VEGF-mediated signaling and affected tumor angiogenesis through PI3K/Akt/VEGF/eNOS pathway.

  19. DAB2IP coordinates both PI3K-Akt and ASK1 pathways for cell survival and apoptosis

    PubMed Central

    Xie, Daxing; Gore, Crystal; Zhou, Jian; Pong, Rey-Chen; Zhang, Haifeng; Yu, Luyang; Vessella, Robert L.; Min, Wang; Hsieh, Jer-Tsong

    2009-01-01

    In metastatic prostate cancer (PCa) cells, imbalance between cell survival and death signals such as constitutive activation of phosphatidylinositol 3-kinase (PI3K)-Akt and inactivation of apoptosis-stimulated kinase (ASK1)-JNK pathways is often detected. Here, we show that DAB2IP protein, often down-regulated in PCa, is a potent growth inhibitor by inducing G0/G1 cell cycle arrest and is proapoptotic in response to stress. Gain of function study showed that DAB2IP can suppress the PI3K-Akt pathway and enhance ASK1 activation leading to cell apoptosis, whereas loss of DAB2IP expression resulted in PI3K-Akt activation and ASK1-JNK inactivation leading to accelerated PCa growth in vivo. Moreover, glandular epithelia from DAB2IP−/− animal exhibited hyperplasia and apoptotic defect. Structural functional analyses of DAB2IP protein indicate that both proline-rich (PR) and PERIOD-like (PER) domains, in addition to the critical role of C2 domain in ASK1 activity, are important for modulating PI3K-Akt activity. Thus, DAB2IP is a scaffold protein capable of bridging both survival and death signal molecules, which implies its role in maintaining cell homeostasis. PMID:19903888

  20. Eupatilin induces human renal cancer cell apoptosis via ROS-mediated MAPK and PI3K/AKT signaling pathways

    PubMed Central

    Zhong, Wei-Feng; Wang, Xiao-Hong; Pan, Bin; Li, Feng; Kuang, Lu; Su, Ze-Xuan

    2016-01-01

    Phosphatidylinositol 3-kinase (PI3K)/AKT and mitogen activated protein kinase (MAPK) signaling cascades have significant roles in cell proliferation, survival, angiogenesis and metastasis of tumor cells. Eupatilin, one of the major compounds present in Artemisia species, has been demonstrated to have antitumor properties. However, the effect of eupatilin in renal cell carcinoma (RCC) remains to be elucidated. Therefore, the present study investigated the biological effects and mechanisms of eupatilin in RCC cell apoptosis. The results of the present study demonstrated that eupatilin significantly induced cell apoptosis and enhanced the production of reactive oxygen species (ROS) in 786-O cells. In addition, eupatilin induced phosphorylation of p38α (Thr180/Tyr182), extracellular signal-regulated kinase 1/2 and c-Jun N-terminal kinase 1/2 (Thr183/Tyr185), and decreased the phosphorylation of PI3K and AKT in 786-O cells in a concentration-dependent manner. Furthermore, the ROS inhibitor N-acetyl-L-cysteine was able to rescue the MAPK activation and PI3K/AKT inhibition induced by eupatilin. Taken together, the results of the present study provide evidence that inhibition of eupatilin induces apoptosis in human RCC via ROS-mediated activation of the MAPK signaling pathway and inhibition of the PI3K/AKT signaling pathway. Thus, eupatilin may serve as a potential therapeutic agent for the treatment of human RCC. PMID:27698876

  1. Aged black garlic extract inhibits HT29 colon cancer cell growth via the PI3K/Akt signaling pathway.

    PubMed

    Dong, Menghua; Yang, Guiqing; Liu, Hanchen; Liu, Xiaoxu; Lin, Sixiang; Sun, Dongning; Wang, Yishan

    2014-03-01

    Accumulating evidence indicates that aged black garlic extract (ABGE) may prove beneficial in preventing or inhibiting oncogenesis; however, the underlying mechanisms have not been fully elucidated. The present study aimed to investigate the effects of ABGE on the proliferation and apoptosis of HT29 colon cancer cells. Our results demonstrated that ABGE inhibited HT29 cell growth via the induction of apoptosis and cell cycle arrest. We further investigated the phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signal transduction pathway and the molecular mechanisms underlying the ABGE-induced inhibition of HT29 cell proliferation. We observed that ABGE may regulate the function of the PI3K/Akt pathway through upregulating PTEN and downregulating Akt and p-Akt expression, as well as suppressing its downstream target, 70-kDa ribosomal protein S6 kinase 1, at the mRNA and protein levels. In conclusion, these findings suggest that the PI3K/Akt signal transduction pathway is crucial for the development of colon cancer. ABGE inhibited the growth and induced apoptosis in HT29 cells through the inhibition of the PI3K/Akt pathway, suggesting that ABGE may be effective in the prevention and treatment of colon cancer in humans. PMID:24649105

  2. Closing escape routes: inhibition of IL-8 signaling enhances the anti-tumor efficacy of PI3K inhibitors.

    PubMed

    Juvekar, Ashish; Wulf, Gerburg M

    2013-04-08

    The phosphoinositide 3-kinase (PI3K) pathway serves as a relay where signals that emanate from the cell membrane are received and converted into intracellular signals that promote proliferation and survival. Inhibitors of PI3K hold promise for the treatment of breast cancer because activation of this pathway is highly prevalent. However, as is increasingly observed with inhibitors of cell signaling, there appear to be mechanisms of primary and secondary resistance. Britschgi and colleagues report that compensatory activation of the IL-8 signaling axis is a mechanism of primary resistance to PI3K inhibitors in some triple-negative breast cancers. In a set of experiments that carefully emulate the clinical scenario in a mouse model, they show that simultaneous inhibition of Janus kinase 2 enhances the efficacy of PI3K/mammalian target of rapamycin inhibition. Their paper lends further support to the concept that successful design of treatments with signal transduction inhibitors must anticipate potential escape routes - and include agents to simultaneously block them.

  3. Eupatilin induces human renal cancer cell apoptosis via ROS-mediated MAPK and PI3K/AKT signaling pathways

    PubMed Central

    Zhong, Wei-Feng; Wang, Xiao-Hong; Pan, Bin; Li, Feng; Kuang, Lu; Su, Ze-Xuan

    2016-01-01

    Phosphatidylinositol 3-kinase (PI3K)/AKT and mitogen activated protein kinase (MAPK) signaling cascades have significant roles in cell proliferation, survival, angiogenesis and metastasis of tumor cells. Eupatilin, one of the major compounds present in Artemisia species, has been demonstrated to have antitumor properties. However, the effect of eupatilin in renal cell carcinoma (RCC) remains to be elucidated. Therefore, the present study investigated the biological effects and mechanisms of eupatilin in RCC cell apoptosis. The results of the present study demonstrated that eupatilin significantly induced cell apoptosis and enhanced the production of reactive oxygen species (ROS) in 786-O cells. In addition, eupatilin induced phosphorylation of p38α (Thr180/Tyr182), extracellular signal-regulated kinase 1/2 and c-Jun N-terminal kinase 1/2 (Thr183/Tyr185), and decreased the phosphorylation of PI3K and AKT in 786-O cells in a concentration-dependent manner. Furthermore, the ROS inhibitor N-acetyl-L-cysteine was able to rescue the MAPK activation and PI3K/AKT inhibition induced by eupatilin. Taken together, the results of the present study provide evidence that inhibition of eupatilin induces apoptosis in human RCC via ROS-mediated activation of the MAPK signaling pathway and inhibition of the PI3K/AKT signaling pathway. Thus, eupatilin may serve as a potential therapeutic agent for the treatment of human RCC.

  4. Inhibition of PI3K by PX-866 prevents transforming growth factor-alpha-induced pulmonary fibrosis.

    PubMed

    Le Cras, Timothy D; Korfhagen, Thomas R; Davidson, Cynthia; Schmidt, Stephanie; Fenchel, Matthew; Ikegami, Machiko; Whitsett, Jeffrey A; Hardie, William D

    2010-02-01

    Transforming growth factor-alpha (TGFalpha) is a ligand for the epidermal growth factor receptor (EGFR). EGFR activation is associated with fibroproliferative processes in human lung disease and animal models of pulmonary fibrosis. EGFR signaling activates several intracellular signaling pathways including phosphatidylinositol 3'-kinase (PI3K). We previously showed that induction of lung-specific TGFalpha expression in transgenic mice caused progressive pulmonary fibrosis over a 4-week period. The increase in levels of phosphorylated Akt, detected after 1 day of doxycycline-induced TGFalpha expression, was blocked by treatment with the PI3K inhibitor, PX-866. Daily administration of PX-866 during TGFalpha induction prevented increases in lung collagen and airway resistance as well as decreases in lung compliance. Treatment of mice with oral PX-866 4 weeks after the induction of TGFalpha prevented additional weight loss and further increases in total collagen, and attenuated changes in pulmonary mechanics. These data show that PI3K is activated in TGFalpha/EGFR-mediated pulmonary fibrosis and support further studies to determine the role of PI3K activation in human lung fibrotic disease, which could be amenable to targeted therapy.

  5. HS-173, a Novel PI3K Inhibitor, Attenuates the Activation of Hepatic Stellate Cells in Liver Fibrosis

    PubMed Central

    Son, Mi Kwon; Ryu, Ye-Lim; Jung, Kyung Hee; Lee, Hyunseung; Lee, Hee Seung; Yan, Hong Hua; Park, Heon Joo; Ryu, Ji-Kan; Suh, Jun–Kyu; Hong, Sungwoo; Hong, Soon-Sun

    2013-01-01

    Hepatic stellate cells (HSCs) are the primary source of matrix components in liver disease such as fibrosis. Phosphatidylinositol 3-kinase (PI3K) signaling in HSCs has been shown to induce fibrogenesis. In this study, we evaluated the anti-fibrotic activity of a novel imidazopyridine analogue (HS-173) in human HSCs as well as mouse liver fibrosis. HS-173 strongly suppressed the growth and proliferation of HSCs and induced the arrest at the G2/M phase and apoptosis in HSCs. Furthermore, it reduced the expression of extracellular matrix components such as collagen type I, which was confirmed by an in vivo study. We also observed that HS-173 blocked the PI3K/Akt signaling pathway in vitro and in vivo. Taken together, HS-173 suppressed fibrotic responses such as cell proliferation and collagen synthesis by blocking PI3K/Akt signaling. Therefore, we suggest that this compound may be an effective therapeutic agent for ameliorating liver fibrosis through the inhibition of PI3K signaling. PMID:24326778

  6. PI3K Phosphorylation Is Linked to Improved Electrical Excitability in an In Vitro Engineered Heart Tissue Disease Model System.

    PubMed

    Kana, Kujaany; Song, Hannah; Laschinger, Carol; Zandstra, Peter W; Radisic, Milica

    2015-09-01

    Myocardial infarction, a prevalent cardiovascular disease, is associated with cardiomyocyte cell death, and eventually heart failure. Cardiac tissue engineering has provided hopes for alternative treatment options, and high-fidelity tissue models for drug discovery. The signal transduction mechanisms relayed in response to mechanoelectrical (physical) stimulation or biochemical stimulation (hormones, cytokines, or drugs) in engineered heart tissues (EHTs) are poorly understood. In this study, an EHT model was used to elucidate the signaling mechanisms involved when insulin was applied in the presence of electrical stimulation, a stimulus that mimics functional heart tissue environment in vitro. EHTs were insulin treated, electrically stimulated, or applied in combination (insulin and electrical stimulation). Electrical excitability parameters (excitation threshold and maximum capture rate) were measured. Protein kinase B (AKT) and phosphatidylinositol-3-kinase (PI3K) phosphorylation revealed that insulin and electrical stimulation relayed electrical excitability through two separate signaling cascades, while there was a negative crosstalk between sustained activation of AKT and PI3K.

  7. Modulatory effects of yerba maté (Ilex paraguariensis) on the PI3K-AKT signaling pathway.

    PubMed

    Arçari, Demétrius Paiva; Santos, Juliana Carvalho; Gambero, Alessandra; Ferraz, Lucio Fábio Caldas; Ribeiro, Marcelo Lima

    2013-10-01

    The aim of this study was to evaluate the effects of yerba maté (YM) extract on the phosphatidylinositol 3-kinase (PI3K)-AKT signaling pathway in vivo. The mice were introduced to either standard- or high-fat diet (HFD). After 8 weeks on an HFD, mice were randomly assigned to one of the two treatment conditions, water or yerba maté extract at 1.0 g/kg. After treatment, glucose blood level and hepatic insulin response were evaluated. Liver tissue was examined to determine the mRNA levels using the PI3K-AKT PCR array. The nuclear translocation of forkhead box O1 (FOXO1) was determined by an electrophoretic mobility-shift assay. Our data demonstrated that yerba maté extract significantly decreased the final body weight, glucose blood levels, and insulin resistance of mice. Molecular analysis demonstrated that an HFD downregulated Akt2, Irs1, Irs2, Pi3kca, Pi3kcg, and Pdk1; after yerba maté treatment, the levels of those genes returned to baseline. In addition, an HFD upregulated Pepck and G6pc and increased FOXO1 nuclear translocation. The intervention downregulated these genes by decreasing FOXO1 nuclear translocation. The results obtained demonstrate for the first time the specific action of yerba maté on the PI3K-AKT pathway, which contributed to the observed improvement in hepatic insulin signaling.

  8. NVP-BKM120, a novel PI3K inhibitor, shows synergism with a STAT3 inhibitor in human gastric cancer cells harboring KRAS mutations

    PubMed Central

    PARK, EUNJU; PARK, JINAH; HAN, SAE-WON; IM, SEOCK-AH; KIM, TAE-YOU; OH, DO-YOUN; BANG, YUNG-JUE

    2012-01-01

    Aberrations of Phosphoinositide 3-kinase (PI3K)/AKT signaling are frequently observed in many types of cancer, promoting its emergence as a promising target for cancer treatment. PI3K can become activated by various pathways, one of which includes RAS. RAS can not only directly activate the PI3K/AKT pathway via binding to p110 of PI3K, but also regulates mTOR via ERK or RSK independently of the PI3K/AKT pathway. Thus, actively mutated RAS can constitutively activate PI3K signaling. Additionally, in RAS tumorigenic transformation, signal transducer and activator of transcription 3 (STAT3) has been known also to be required. In this study, we examined the efficacy of NVP-BKM120, a pan-class I PI3K inhibitor in human gastric cancer cells and hypothesized that the combined inhibition of PI3K and STAT3 would be synergistic in KRAS mutant gastric cancer cells. NVP-BKM120 demonstrated anti-proliferative activity in 11 human gastric cancer cell lines by decreasing mTOR downstream signaling. But NVP-BKM120 treatment increased p-AKT by subsequent abrogation of feedback inhibition by stabilizing insulin receptor substrate-1. In KRAS mutant gastric cancer cells, either p-ERK or p-STAT3 was also increased upon treatment of NVP-BKM120. The synergistic efficacy study demonstrated that dual PI3K and STAT3 blockade showed a synergism in cells harboring mutated KRAS by inducing apoptosis. The synergistic effect was not seen in KRAS wild-type cells. Together, these findings suggest for the first time that the dual inhibition of PI3K and STAT3 signaling may be an effective therapeutic strategy for KRAS mutant gastric cancer patients. PMID:22159814

  9. The role of the PI3K-Akt signal transduction pathway in Autographa californica multiple nucleopolyhedrovirus infection of Spodoptera frugiperda cells

    SciTech Connect

    Xiao Wei; Yang Yi; Weng Qingbei; Lin Tiehao; Yuan Meijin; Yang Kai; Pang Yi

    2009-08-15

    Many viruses activate the phosphatidylinositol 3-kinase (PI3K)-Akt signaling pathway, thereby modulating diverse downstream signaling pathways associated with antiapoptosis, proliferation, cell cycling, protein synthesis and glucose metabolism, in order to augment their replication. To date, the role of the PI3K-Akt pathway in Baculovirus replication has not been defined. In the present study, we demonstrate that infection of Sf9 cells with Autographa californica multiple nucleopolyhedrovirus (AcMNPV) elevated cellular Akt phosphorylation at 1 h post-infection. The maximum Akt phosphorylation occurred at 6 h post-infection and remained unchanged until 18 h post-infection. The PI3K-specific inhibitor, LY294002, suppressed Akt phosphorylation in a dose-dependent manner, suggesting that AcMNPV-induced Akt phosphorylation is PI3K-dependent. The inhibition of PI3K-Akt activation by LY294002 significantly reduced the viral yield, including a reduction in budded viruses and occlusion bodies. The virus production was reduced only when the inhibitor was added within 24 h of infection, implying that activation of PI3K occurred early in infection. Correspondingly, both viral DNA replication and late (VP39) and very late (POLH) viral protein expression were impaired by LY294002 treatment; LY294002 had no effect on immediate-early (IE1) and early-late (GP64) protein expression. These results demonstrate that the PI3K-Akt pathway is required for efficient Baculovirus replication.

  10. Clinical implications of Girdin and PI3K protein expression in breast cancer

    PubMed Central

    JIN, FENG; LIU, CAIGANG; GUO, YANG; CHEN, HAO; WU, YUNFEI

    2013-01-01

    The aim of this study was to investigate the correlation between Girdin and PI3K in breast cancer stem cells and the clinical implications of the co-expression of these two proteins in breast cancer patients. CD44+/CD24− tumor cells from the MD-231 cell line were sorted by flow cytometry. The expression status of Girdin and PI3K proteins was detected using western blotting and immunohistochemical staining. The relationship between Girdin and PI3K proteins and clinicopathological parameters was analyzed in 820 breast cancer patients. Girdin and PI3K proteins were more highly expressed in CD44+/CD24− tumor stem cells compared to the control group and Girdin and PI3K proteins were co-immunoprecipitated in the MD-231 cell line. Of the 820 enrolled breast cancer patients, Girdin and PI3K proteins were expressed in 295 (35.98%) and 492 (60.00%) cases, respectively. There were 162 (19.76%) cases which co-expressed Girdin and PI3K proteins. Univariate and multivariate analyses indicated that the co-expression of Girdin and PI3K proteins correlated with histological type, metastatic nodes and distant metastasis (P=0.01, 0.001 and 0.001, respectively). After analyzing survival rates, cases with Girdin and PI3K co-expression were shown to attain a significantly increased distant metastasis rate and poorer postoperative, disease-specific survival compared to those with Girdin and PI3K co-expression (P=0.001). In the Cox regression test, Girdin and PI3K co-expression was detected as an independent prognostic factor (P=0.001). Girdin may regulate the biological behavior of breast cancer via the PI3K/Akt/mTOR pathway, and thus, serve as a potential new target for breast cancer treatment. PMID:23760650

  11. Learning improvement after PI3K activation correlates with de novo formation of functional small spines

    PubMed Central

    Enriquez-Barreto, Lilian; Cuesto, Germán; Dominguez-Iturza, Nuria; Gavilán, Elena; Ruano, Diego; Sandi, Carmen; Fernández-Ruiz, Antonio; Martín-Vázquez, Gonzalo; Herreras, Oscar; Morales, Miguel

    2014-01-01

    PI3K activation promotes the formation of synaptic contacts and dendritic spines, morphological features of glutamatergic synapses that are commonly known to be related to learning processes. In this report, we show that in vivo administration of a peptide that activates the PI3K signaling pathway increases spine density in the rat hippocampus and enhances the animals’ cognitive abilities, while in vivo electrophysiological recordings show that PI3K activation results in synaptic enhancement of Schaffer and stratum lacunosum moleculare inputs. Morphological characterization of the spines reveals that subjecting the animals to contextual fear-conditioning training per se promotes the formation of large spines, while PI3K activation reverts this effect and favors a general change toward small head areas. Studies using hippocampal neuronal cultures show that the PI3K spinogenic process is NMDA-dependent and activity-independent. In culture, PI3K activation was followed by mRNA upregulation of glutamate receptor subunits and of the immediate-early gene Arc. Time-lapse studies confirmed the ability of PI3K to induce the formation of small spines. Finally, we demonstrate that the spinogenic effect of PI3K can be induced in the presence of neurodegeneration, such as in the Tg2576 Alzheimer’s mouse model. These findings highlight that the PI3K pathway is an important regulator of neuronal connectivity and stress the relationship between spine size and learning processes. PMID:24427113

  12. PI3K/AKT Signaling Pathway Is Essential for Survival of Induced Pluripotent Stem Cells

    PubMed Central

    Hossini, Amir M.; Quast, Annika S.; Plötz, Michael; Grauel, Katharina; Exner, Tarik; Küchler, Judit; Stachelscheid, Harald; Eberle, Jürgen; Rabien, Anja

    2016-01-01

    Apoptosis is a highly conserved biochemical mechanism which is tightly controlled in cells. It contributes to maintenance of tissue homeostasis and normally eliminates highly proliferative cells with malignant properties. Induced pluripotent stem cells (iPSCs) have recently been described with significant functional and morphological similarities to embryonic stem cells. Human iPSCs are of great hope for regenerative medicine due to their broad potential to differentiate into specialized cell types in culture. They may be useful for exploring disease mechanisms and may provide the basis for future cell-based replacement therapies. However, there is only poor insight into iPSCs cell signaling as the regulation of apoptosis. In this study, we focused our attention on the apoptotic response of Alzheimer fibroblast-derived iPSCs and two other Alzheimer free iPSCs to five biologically relevant kinase inhibitors as well as to the death ligand TRAIL. To our knowledge, we are the first to report that the relatively high basal apoptotic rate of iPSCs is strongly suppressed by the pancaspase inhibitor QVD-Oph, thus underlining the dependency on proapoptotic caspase cascades. Furthermore, wortmannin, an inhibitor of phosphoinositid-3 kinase / Akt signaling (PI3K-AKT), dramatically and rapidly induced apoptosis in iPSCs. In contrast, parental fibroblasts as well as iPSC-derived neuronal cells were not responsive. The resulting condensation and fragmentation of DNA and decrease of the membrane potential are typical features of apoptosis. Comparable effects were observed with an AKT inhibitor (MK-2206). Wortmannin resulted in disappearance of phosphorylated AKT and activation of the main effector caspase-3 in iPSCs. These results clearly demonstrate for the first time that PI3K-AKT represents a highly essential survival signaling pathway in iPSCs. The findings provide improved understanding on the underlying mechanisms of apoptosis regulation in iPSCs. PMID:27138223

  13. Loss of NDRG2 expression activates PI3K-AKT signalling via PTEN phosphorylation in ATLL and other cancers

    PubMed Central

    Nakahata, Shingo; Ichikawa, Tomonaga; Maneesaay, Phudit; Saito, Yusuke; Nagai, Kentaro; Tamura, Tomohiro; Manachai, Nawin; Yamakawa, Norio; Hamasaki, Makoto; Kitabayashi, Issay; Arai, Yasuhito; Kanai, Yae; Taki, Tomohiko; Abe, Takaya; Kiyonari, Hiroshi; Shimoda, Kazuya; Ohshima, Koichi; Horii, Akira; Shima, Hiroshi; Taniwaki, Masafumi; Yamaguchi, Ryoji; Morishita, Kazuhiro

    2014-01-01

    Constitutive phosphatidylinositol 3-kinase (PI3K)-AKT activation has a causal role in adult T-cell leukaemia-lymphoma (ATLL) and other cancers. ATLL cells do not harbour genetic alterations in PTEN and PI3KCA but express high levels of PTEN that is highly phosphorylated at its C-terminal tail. Here we report a mechanism for the N-myc downstream-regulated gene 2 (NDRG2)-dependent regulation of PTEN phosphatase activity via the dephosphorylation of PTEN at the Ser380, Thr382 and Thr383 cluster within the C-terminal tail. We show that NDRG2 is a PTEN-binding protein that recruits protein phosphatase 2A (PP2A) to PTEN. The expression of NDRG2 is frequently downregulated in ATLL, resulting in enhanced phosphorylation of PTEN at the Ser380/Thr382/Thr383 cluster and enhanced activation of the PI3K-AKT pathway. Given the high incidence of T-cell lymphoma and other cancers in NDRG2-deficient mice, PI3K-AKT activation via enhanced PTEN phosphorylation may be critical for the development of cancer. PMID:24569712

  14. Non-canonical antagonism of PI3K by the kinase Itpkb delays thymocyte β-selection and renders it Notch-dependent

    PubMed Central

    Westernberg, Luise; Conche, Claire; Huang, Yina Hsing; Rigaud, Stephanie; Deng, Yisong; Siegemund, Sabine; Mukherjee, Sayak; Nosaka, Lyn'Al; Das, Jayajit; Sauer, Karsten

    2016-01-01

    β-selection is the most pivotal event determining αβ T cell fate. Here, surface-expression of a pre-T cell receptor (pre-TCR) induces thymocyte metabolic activation, proliferation, survival and differentiation. Besides the pre-TCR, β-selection also requires co-stimulatory signals from Notch receptors - key cell fate determinants in eukaryotes. Here, we show that this Notch-dependence is established through antagonistic signaling by the pre-TCR/Notch effector, phosphoinositide 3-kinase (PI3K), and by inositol-trisphosphate 3-kinase B (Itpkb). Canonically, PI3K is counteracted by the lipid-phosphatases Pten and Inpp5d/SHIP-1. In contrast, Itpkb dampens pre-TCR induced PI3K/Akt signaling by producing IP4, a soluble antagonist of the Akt-activating PI3K-product PIP3. Itpkb-/- thymocytes are pre-TCR hyperresponsive, hyperactivate Akt, downstream mTOR and metabolism, undergo an accelerated β-selection and can develop to CD4+CD8+ cells without Notch. This is reversed by inhibition of Akt, mTOR or glucose metabolism. Thus, non-canonical PI3K-antagonism by Itpkb restricts pre-TCR induced metabolic activation to enforce coincidence-detection of pre-TCR expression and Notch-engagement. DOI: http://dx.doi.org/10.7554/eLife.10786.001 PMID:26880557

  15. Inhibition of class IA PI3K enzymes in non-small cell lung cancer cells uncovers functional compensation among isoforms.

    PubMed

    Stamatkin, Christopher; Ratermann, Kelley L; Overley, Colleen W; Black, Esther P

    2015-01-01

    Deregulation of the phosphatidylinositol 3-kinase (PI3K) pathway is central to many human malignancies while normal cell proliferation requires pathway functionality. Although inhibitors of the PI3K pathway are in clinical trials or approved for therapy, an understanding of the functional activities of pathway members in specific malignancies is needed. In lung cancers, the PI3K pathway is often aberrantly activated by mutation of genes encoding EGFR, KRAS, and PIK3CA proteins. We sought to understand whether class IA PI3K enzymes represent rational therapeutic targets in cells of non-squamous lung cancers by exploring pharmacological and genetic inhibitors of PI3K enzymes in a non-small cell lung cancer (NSCLC) cell line system. We found that class IA PI3K enzymes were expressed in all cell lines tested, but treatment of NSCLC lines with isoform-selective inhibitors (A66, TGX-221, CAL-101 and IC488743) had little effect on cell proliferation or prolonged inhibition of AKT activity. Inhibitory pharmacokinetic and pharmacodynamic responses were observed using these agents at non-isoform selective concentrations and with the pan-class I (ZSTK474) agent. Response to pharmacological inhibition suggested that PI3K isoforms may functionally compensate for one another thus limiting efficacy of single agent treatment. However, combination of ZSTK474 and an EGFR inhibitor (erlotinib) in NSCLC resistant to each single agent reduced cellular proliferation. These studies uncovered unanticipated cellular responses to PI3K isoform inhibition in NSCLC that does not correlate with PI3K mutations, suggesting that patients bearing tumors with wildtype EGFR and KRAS are unlikely to benefit from inhibitors of single isoforms but may respond to pan-isoform inhibition.

  16. Activation of the PI3K/AKT pathway correlates with prognosis in stage II colon cancer

    PubMed Central

    Malinowsky, K; Nitsche, U; Janssen, K-P; Bader, F G; Späth, C; Drecoll, E; Keller, G; Höfler, H; Slotta-Huspenina, J; Becker, K-F

    2014-01-01

    Background: Patients with UICC/AJCC stage II colon cancer have a high 5-year overall survival rate after surgery. Nevertheless, a significant subgroup of patients develops tumour recurrence. Currently, there are no clinically established biomarkers available to identify this patient group. We applied reverse-phase protein arrays (RPPA) for phosphatidylinositide-3-kinase pathway activation mapping to stratify patients according to their risk of tumour recurrence after surgery. Methods: Full-length proteins were extracted from formalin-fixed, paraffin-embedded tissue samples of 118 patients who underwent curative resection. RPPA technology was used to analyse expression and/or phosphorylation levels of six major factors of the phosphatidylinositide-3-kinase pathway. Oncogenic mutations of KRAS and BRAF, and DNA microsatellite status, currently discussed as prognostic markers, were analysed in parallel. Results: Expression of phospho-AKT (HR=3.52; P=0.032), S6RP (HR=6.3; P=0.044), and phospho-4E-BP1 (HR=4.12; P=0.011) were prognostic factors for disease-free survival. None of the molecular genetic alterations were significantly associated with prognosis. Conclusions: Our data indicate that activation of the PI3K/AKT pathway evidenced on the protein level might be a valuable prognostic marker to stratify patients for their risk of tumour recurrence. Beside adjuvant chemotherapy targeting of upregulated PI3K/AKT signalling may be an attractive strategy for treatment of high-risk patients. PMID:24619078

  17. PI3K inhibitors as new cancer therapeutics: implications for clinical trial design

    PubMed Central

    Massacesi, Cristian; Di Tomaso, Emmanuelle; Urban, Patrick; Germa, Caroline; Quadt, Cornelia; Trandafir, Lucia; Aimone, Paola; Fretault, Nathalie; Dharan, Bharani; Tavorath, Ranjana; Hirawat, Samit

    2016-01-01

    The PI3K–AKT–mTOR pathway is frequently activated in cancer. PI3K inhibitors, including the pan-PI3K inhibitor buparlisib (BKM120) and the PI3Kα-selective inhibitor alpelisib (BYL719), currently in clinical development by Novartis Oncology, may therefore be effective as anticancer agents. Early clinical studies with PI3K inhibitors have demonstrated preliminary antitumor activity and acceptable safety profiles. However, a number of unanswered questions regarding PI3K inhibition in cancer remain, including: what is the best approach for different tumor types, and which biomarkers will accurately identify the patient populations most likely to benefit from specific PI3K inhibitors? This review summarizes the strategies being employed by Novartis Oncology to help maximize the benefits of clinical studies with buparlisib and alpelisib, including stratification according to PI3K pathway activation status, selective enrollment/target enrichment (where patients with PI3K pathway-activated tumors are specifically recruited), nonselective enrollment with mandatory tissue collection, and enrollment of patients who have progressed on previous targeted agents, such as mTOR inhibitors or endocrine therapy. An overview of Novartis-sponsored and Novartis-supported trials that are utilizing these approaches in a range of cancer types, including breast cancer, head and neck squamous cell carcinoma, non-small cell lung carcinoma, lymphoma, and glioblastoma multiforme, is also described. PMID:26793003

  18. Somatic mutations in PI3K[alpha]: Structural basis for enzyme activation and drug design

    SciTech Connect

    Gabelli, Sandra B.; Mandelker, Diana; Schmidt-Kittler, Oleg; Vogelstein, Bert; Amzel, L. Mario

    2011-09-06

    The PI3K pathway is a communication hub coordinating critical cell functions including cell survival, cell growth, proliferation, motility and metabolism. Because PI3K{alpha} harbors recurrent somatic mutations resulting in gains of function in human cancers, it has emerged as an important drug target for many types of solid tumors. Various PI3K isoforms are also being evaluated as potential therapeutic targets for inflammation, heart disease, and hematological malignancies. Structural biology is providing insights into the flexibility of the PI3Ks, and providing basis for understanding the effects of mutations, drug resistance and specificity.

  19. The PI 3-kinase and mTOR signaling pathways are important modulators of epithelial tubule formation.

    PubMed

    Walid, Shereaf; Eisen, Randi; Ratcliffe, Don R; Dai, Kezhi; Hussain, M Mahmood; Ojakian, George K

    2008-08-01

    Using MDCK cells as a model system, evidence is presented demonstrating that the signaling pathways mammalian target of rapamycin (mTOR) and phosphoinositide 3-kinase (PI 3-kinase) play important roles in the regulation of epithelial tubule formation. Incubation of cells with collagen gel overlays induced early (4-8 h) reorganization of cells (epithelial remodeling) into three-dimensional multicellular tubular structures over 24 h. An MDCK cell line stably expressing the PH domain of Akt, a PI 3-kinase downstream effector, coupled to green fluorescent protein (GFP-Akt-PH) was used to determine the distribution of phosphatidyl inositol-3,4,5-P(3) (PIP(3)), a product of PI 3-kinase. GFP-Akt-PH was associated with lateral membranes in control cells. After incubation with collagen gel overlays, GFP-Akt-PH redistributed into the lamellipodia of migrating cells suggesting that PIP(3) plays a role in epithelial remodeling. Using the small molecule inhibitor LY-294002 that inhibits both mTOR and PI 3-kinase, we demonstrated that kinase activity was required for epithelial remodeling, disruption of cell junctions and subsequent modulation of tubule formation. Since the mTOR signaling pathway is downstream of PI 3-kinase, the effects of rapamycin, a specific mTOR inhibitor, on tubule formation were assessed. Rapamycin did not affect epithelial remodeling or GFP-Akt-PH redistribution but inhibited elongated tubule formation that occurred later (24 h) in morphogenesis. These results were further supported by using RNA interference to down-regulate mTOR and inhibit tubule formation. Our studies demonstrate that PI 3-kinase regulates early epithelial remodeling stages while mTOR modulates latter stages of tubule development. PMID:18366086

  20. Arctigenin Increases Hemeoxygenase-1 Gene Expression by Modulating PI3K/AKT Signaling Pathway in Rat Primary Astrocytes.

    PubMed

    Jeong, Yeon-Hui; Park, Jin-Sun; Kim, Dong-Hyun; Kim, Hee-Sun

    2014-11-01

    In the present study, we found that the natural compound arctigenin inhibited hydrogen peroxide-induced reactive oxygen species (ROS) production in rat primary astrocytes. Since hemeoxygenase-1 (HO-1) plays a critical role as an antioxidant defense factor in the brain, we examined the effect of arctigenin on HO-1 expression in rat primary astrocytes. We found that arctigenin increased HO-1 mRNA and protein levels. Arctigenin also increases the nuclear translocation and DNA binding of Nrf2/c-Jun to the antioxidant response element (ARE) on HO-1 promoter. In addition, arctigenin increased ARE-mediated transcriptional activities in rat primary astrocytes. Further mechanistic studies revealed that arctigenin increased the phosphorylation of AKT, a downstream substrate of phosphatidylinositol 3-kinase (PI3K). Treatment of cells with a PI3K-specific inhibitor, LY294002, suppressed the HO-1 expression, Nrf2 DNA binding and ARE-mediated transcriptional activities in arctigenin-treated astrocyte cells. The results collectively suggest that PI3K/AKT signaling pathway is at least partly involved in HO-1 expression by arctigenin via modulation of Nrf2/ARE axis in rat primary astrocytes.

  1. Delayed glial clearance of degenerating axons in aged Drosophila is due to reduced PI3K/Draper activity.

    PubMed

    Purice, Maria D; Speese, Sean D; Logan, Mary A

    2016-01-01

    Advanced age is the greatest risk factor for neurodegenerative disorders, but the mechanisms that render the senescent brain vulnerable to disease are unclear. Glial immune responses provide neuroprotection in a variety of contexts. Thus, we explored how glial responses to neurodegeneration are altered with age. Here we show that glia-axon phagocytic interactions change dramatically in the aged Drosophila brain. Aged glia clear degenerating axons slowly due to low phosphoinositide-3-kinase (PI3K) signalling and, subsequently, reduced expression of the conserved phagocytic receptor Draper/MEGF10. Importantly, boosting PI3K/Draper activity in aged glia significantly reverses slow phagocytic responses. Moreover, several hours post axotomy, early hallmarks of Wallerian degeneration (WD) are delayed in aged flies. We propose that slow clearance of degenerating axons is mechanistically twofold, resulting from deferred initiation of axonal WD and reduced PI3K/Draper-dependent glial phagocytic function. Interventions that boost glial engulfment activity, however, can substantially reverse delayed clearance of damaged neuronal debris. PMID:27647497

  2. Targeting the PI3K/Akt signaling pathway in gastric carcinoma: A reality for personalized medicine?

    PubMed Central

    Singh, Shikha Satendra; Yap, Wei Ney; Arfuso, Frank; Kar, Shreya; Wang, Chao; Cai, Wanpei; Dharmarajan, Arunasalam M; Sethi, Gautam; Kumar, Alan Prem

    2015-01-01

    Frequent activation of phosphatidylinositol-3 kinases (PI3K)/Akt/mTOR signaling pathway in gastric cancer (GC) is gaining immense popularity with identification of mutations and/or amplifications of PIK3CA gene or loss of function of PTEN, a tumor suppressor protein, to name a few; both playing a crucial role in regulating this pathway. These aberrations result in dysregulation of this pathway eventually leading to gastric oncogenesis, hence, there is a need for targeted therapy for more effective anticancer treatment. Several inhibitors are currently in either preclinical or clinical stages for treatment of solid tumors like GC. With so many inhibitors under development, further studies on predictive biomarkers are needed to measure the specificity of any therapeutic intervention. Herein, we review the common dysregulation of PI3K/Akt/mTOR pathway in GC and the various types of single or dual pathway inhibitors under development that might have a superior role in GC treatment. We also summarize the recent developments in identification of predictive biomarkers and propose use of predictive biomarkers to facilitate more personalized cancer therapy with effective PI3K/Akt/mTOR pathway inhibition. PMID:26604635

  3. High expression of VEGF and PI3K in glioma stem cells provides new criteria for the grading of gliomas

    PubMed Central

    WANG, LEI; ZHANG, LUYAO; SHEN, WEIGAO; LIU, YANBO; LUO, YINAN

    2016-01-01

    Glioma is a type of tumor derived from glial cells, which is associated with a high level of incidence and mortality. At present, the generation of a fast and efficient method to evaluate the malignancy grade of glioma is required. Cancer stem cells (CSCs) are currently attracting attention in oncological studies; therefore, the present study aimed to investigate novel biomarkers of glioma CSCs, in order to provide new criteria for the grading of glioma. The mRNA expression levels of CD133, (sex determining region Y)-box 2, nestin, vascular endothelial growth factor (VEGF) and phosphoinositide-3-kinase (PI3K) were detected in 15 human samples of high-malignancy glioma and 12 human samples of low-malignancy glioma in vitro. The mRNA expression levels of VEGF and PI3K were higher in the high-malignancy group, as compared with in the low-malignancy group. In conclusion, the mRNA expression levels of VEGF and PI3K in glioma CSCs may be considered a novel criteria for the grading of glioma. PMID:26893649

  4. Arctigenin Increases Hemeoxygenase-1 Gene Expression by Modulating PI3K/AKT Signaling Pathway in Rat Primary Astrocytes.

    PubMed

    Jeong, Yeon-Hui; Park, Jin-Sun; Kim, Dong-Hyun; Kim, Hee-Sun

    2014-11-01

    In the present study, we found that the natural compound arctigenin inhibited hydrogen peroxide-induced reactive oxygen species (ROS) production in rat primary astrocytes. Since hemeoxygenase-1 (HO-1) plays a critical role as an antioxidant defense factor in the brain, we examined the effect of arctigenin on HO-1 expression in rat primary astrocytes. We found that arctigenin increased HO-1 mRNA and protein levels. Arctigenin also increases the nuclear translocation and DNA binding of Nrf2/c-Jun to the antioxidant response element (ARE) on HO-1 promoter. In addition, arctigenin increased ARE-mediated transcriptional activities in rat primary astrocytes. Further mechanistic studies revealed that arctigenin increased the phosphorylation of AKT, a downstream substrate of phosphatidylinositol 3-kinase (PI3K). Treatment of cells with a PI3K-specific inhibitor, LY294002, suppressed the HO-1 expression, Nrf2 DNA binding and ARE-mediated transcriptional activities in arctigenin-treated astrocyte cells. The results collectively suggest that PI3K/AKT signaling pathway is at least partly involved in HO-1 expression by arctigenin via modulation of Nrf2/ARE axis in rat primary astrocytes. PMID:25489416

  5. GLCCI1 is a novel component associated with the PI3K signaling pathway in podocyte foot processes

    PubMed Central

    Kim, Sang-Hoon; Kim, Hyun-Jung; Kim, Chan-Wha

    2016-01-01

    Podocyte foot processes are interdigitated to form the slit diaphragm and are crucial for the glomerular filtration barrier. Glucocorticoid-induced transcript 1 (GLCCI1) is transcriptionally regulated, but its signaling pathway in podocytes is unknown. The main objective of this study was to investigate the regulation of podocyte foot process proteins and to investigate the role of GLCCI1 in the phosphoinositide 3-kinase (PI3K) pathway using high glucose-induced podocytes and streptozotocin-induced diabetic rats. In podocytes and rat kidneys, GLCCI1 was found to be highly specific for the glomerulus and podocyte foot processes similar to other podocyte-specific proteins (nephrin, podocin, synatopodin and podocalyxin) based on reverse transcription-PCR, western blotting, immunofluorescence and immunoelectron microscopy analyses. In addition, the decrease in the GLCCI1 expression level under hyperglycemic conditions was restored by treatment with a PI3K inhibitor (wortmannin). Immunofluorescence analysis confirmed that GLCCI1 colocalized with nephrin and synaptopodin both in vivo and in vitro. Finally, immunoelectron microscopy data from streptozotocin-induced diabetic rats showed that GLCCI1 also localized in podocyte foot processes. Hence, GLCCI1 is a component of podocyte foot processes, and its expression appears to be regulated via the PI3K pathway. PMID:27174202

  6. Delayed glial clearance of degenerating axons in aged Drosophila is due to reduced PI3K/Draper activity

    PubMed Central

    Purice, Maria D.; Speese, Sean D.; Logan, Mary A.

    2016-01-01

    Advanced age is the greatest risk factor for neurodegenerative disorders, but the mechanisms that render the senescent brain vulnerable to disease are unclear. Glial immune responses provide neuroprotection in a variety of contexts. Thus, we explored how glial responses to neurodegeneration are altered with age. Here we show that glia–axon phagocytic interactions change dramatically in the aged Drosophila brain. Aged glia clear degenerating axons slowly due to low phosphoinositide-3-kinase (PI3K) signalling and, subsequently, reduced expression of the conserved phagocytic receptor Draper/MEGF10. Importantly, boosting PI3K/Draper activity in aged glia significantly reverses slow phagocytic responses. Moreover, several hours post axotomy, early hallmarks of Wallerian degeneration (WD) are delayed in aged flies. We propose that slow clearance of degenerating axons is mechanistically twofold, resulting from deferred initiation of axonal WD and reduced PI3K/Draper-dependent glial phagocytic function. Interventions that boost glial engulfment activity, however, can substantially reverse delayed clearance of damaged neuronal debris. PMID:27647497

  7. Arctigenin Increases Hemeoxygenase-1 Gene Expression by Modulating PI3K/AKT Signaling Pathway in Rat Primary Astrocytes

    PubMed Central

    Jeong, Yeon-Hui; Park, Jin-Sun; Kim, Dong-Hyun; Kim, Hee-Sun

    2014-01-01

    In the present study, we found that the natural compound arctigenin inhibited hydrogen peroxide-induced reactive oxygen species (ROS) production in rat primary astrocytes. Since hemeoxygenase-1 (HO-1) plays a critical role as an antioxidant defense factor in the brain, we examined the effect of arctigenin on HO-1 expression in rat primary astrocytes. We found that arctigenin increased HO-1 mRNA and protein levels. Arctigenin also increases the nuclear translocation and DNA binding of Nrf2/c-Jun to the antioxidant response element (ARE) on HO-1 promoter. In addition, arctigenin increased ARE-mediated transcriptional activities in rat primary astrocytes. Further mechanistic studies revealed that arctigenin increased the phosphorylation of AKT, a downstream substrate of phosphatidylinositol 3-kinase (PI3K). Treatment of cells with a PI3K-specific inhibitor, LY294002, suppressed the HO-1 expression, Nrf2 DNA binding and ARE-mediated transcriptional activities in arctigenin-treated astrocyte cells. The results collectively suggest that PI3K/AKT signaling pathway is at least partly involved in HO-1 expression by arctigenin via modulation of Nrf2/ARE axis in rat primary astrocytes. PMID:25489416

  8. Fucosylated chondroitin sulfate from sea cucumber improves insulin sensitivity via activation of PI3K/PKB pathway.

    PubMed

    Hu, Shiwei; Chang, Yaoguang; He, Min; Wang, Jingfeng; Wang, Yuming; Xue, Changhu

    2014-07-01

    This study was to investigate the effects of fucosylated chondroitin sulfate (CHS) from sea cucumber on insulin sensitivity in skeletal muscle of type 2 diabetic mice induced by a high-fat high-sucrose diet (HFSD). CHS supplementation for 19 wk significantly improved insulin sensitivity by 20%, and reduced blood glucose and insulin levels. Western blotting assay showed that CHS significantly increased insulin-stimulated glucose transporter 4 (GLUT4) translocation to 1.7-fold, phosphorylation of phosphoinositide 3-kinase (PI3K) at p85 to 5.0-fold, protein kinase B (PKB) at Ser473 to 1.5-fold, and Thr308 to 1.6-fold in skeletal muscle. However, PI3K, PKB, and GLUT4 total proteins expression were unchangeable. In addition, qRT-PCR analysis proved that the insulin signaling was activated by CHS treatment, showing the increased mRNA expressions of glucose uptake-related key genes. It indicated that CHS improved insulin sensitivity by activation of PI3K/PKB signaling in skeletal muscle of type 2 diabetic mice. Identification of potential mechanism by which CHS increased insulin sensitivity might provide a new functional food or pharmaceutical application of sea cucumber.

  9. Membrane translocation of TRPC6 channels and endothelial migration are regulated by calmodulin and PI3 kinase activation

    PubMed Central

    Chaudhuri, Pinaki; Rosenbaum, Michael A.; Sinharoy, Pritam; Damron, Derek S.; Birnbaumer, Lutz; Graham, Linda M.

    2016-01-01

    Lipid oxidation products, including lysophosphatidylcholine (lysoPC), activate canonical transient receptor potential 6 (TRPC6) channels leading to inhibition of endothelial cell (EC) migration in vitro and delayed EC healing of arterial injuries in vivo. The precise mechanism through which lysoPC activates TRPC6 channels is not known, but calmodulin (CaM) contributes to the regulation of TRPC channels. Using site-directed mutagenesis, cDNAs were generated in which Tyr99 or Tyr138 of CaM was replaced with Phe, generating mutant CaM, Phe99-CaM, or Phe138-CaM, respectively. In ECs transiently transfected with pcDNA3.1-myc-His-Phe99-CaM, but not in ECs transfected with pcDNA3.1-myc-His-Phe138-CaM, the lysoPC-induced TRPC6-CaM dissociation and TRPC6 externalization was disrupted. Also, the lysoPC-induced increase in intracellular calcium concentration was inhibited in ECs transiently transfected with pcDNA3.1-myc-His-Phe99-CaM. Blocking phosphorylation of CaM at Tyr99 also reduced CaM association with the p85 subunit and subsequent activation of phosphatidylinositol 3-kinase (PI3K). This prevented the increase in phosphatidylinositol (3,4,5)-trisphosphate (PIP3) and the translocation of TRPC6 to the cell membrane and reduced the inhibition of EC migration by lysoPC. These findings suggest that lysoPC induces CaM phosphorylation at Tyr99 by a Src family kinase and that phosphorylated CaM activates PI3K to produce PIP3, which promotes TRPC6 translocation to the cell membrane. PMID:26858457

  10. Suppression of MicroRNA-203 improves survival of rat bone marrow mesenchymal stem cells through enhancing PI3K-induced cellular activation.

    PubMed

    Liu, Tao; Fu, Nan-Nan; Song, Hong-Li; Wang, Yu-Liang; Wu, Ben-Juan; Shen, Zhong-Yang

    2014-03-23

    As a group of heterogeneous multipotent cells, mesenchymal stem cells (MSCs) have potential in treatment of a variety of clinical diseases. However, the low survival of the transplanted MSCs reduced their therapeutic effects. In this study, we revealed that rno-miR-203 suppressed activity and colony formation and enhanced apoptosis of the rat bone marrow-derived MSCs (BM-MSCs). Using bioinformatics analysis, we found a potential miR-203 binding site within rat phosphatidylinositol 3-kinase (PI3K) 3'UTR, and fluorescent reporter experiments validated the direct and negative regulation of PI3K expression by miR-203 through this site. Ectopic expression of PI3K rescued BM-MSCs from depressed activity induced by miR-203, and suppression of PI3K attenuated the increased BM-MSCs activity by miR-203 inhibitor treatment. Moreover, miR-203 blocking partly protected BM-MSCs from impairment caused by low nutrition. We conclude that inhibition of endogenous miR-203 elevated PI3K expression, which may strengthen PI3K/Akt pathway and promote BM-MSCs activity and survival. © 2014 IUBMB Life, 2014.

  11. Intracellular reactive oxygen species are essential for PI3K/Akt/mTOR-dependent IL-7-mediated viability of T-cell acute lymphoblastic leukemia cells.

    PubMed

    Silva, A; Gírio, A; Cebola, I; Santos, C I; Antunes, F; Barata, J T

    2011-06-01

    Interleukin-7 (IL-7) activates phosphoinositide 3-kinase/Akt/mammalian target of rapamycin (PI3K/Akt/mTOR) pathway, thereby mediating viability, proliferation and growth of T-cell acute lymphoblastic leukemia (T-ALL) cells. Reactive oxygen species (ROS) can be upregulated by growth factors and are known to regulate proliferation and viability. Here, we show that IL-7 upregulates ROS in T-ALL cells in a manner that is dependent on PI3K/Akt/mTOR pathway activity and that relies on both NADPH oxidase and mitochondrial respiratory chain. Conversely, IL-7-induced activation of PI3K signaling pathway requires mitochondrial respiration and ROS. We have previously shown that IL-7-mediated activation of PI3K pathway drives the upregulation of the glucose transporter Glut1, promoting glucose uptake in T-ALL cells. Using phloretin to inhibit Glut function, we demonstrate that glucose uptake is mandatory for ROS upregulation in IL-7-treated T-ALL cells, suggesting that IL-7 stimulation leads to increased ROS via PI3K pathway activation and consequent upregulation of Glut1 and glucose uptake. Overall, our data reveal the existence of a critical crosstalk between PI3K/Akt signaling pathway and ROS that is essential for IL-7-mediated T-ALL cell survival, and that may constitute a novel target for therapeutic intervention. PMID:21455214

  12. Ramentaceone, a Naphthoquinone Derived from Drosera sp., Induces Apoptosis by Suppressing PI3K/Akt Signaling in Breast Cancer Cells

    PubMed Central

    Kawiak, Anna; Lojkowska, Ewa

    2016-01-01

    The phosphoinositide 3-kinase (PI3K) signaling pathway plays an important role in processes critical for breast cancer progression and its upregulation confers increased resistance of cancer cells to chemotherapy and radiation. The present study aimed at determining the activity of ramentaceone, a constituent of species in the plant genera Drosera, toward breast cancer cells and defining the involvement of PI3K/Akt inhibition in ramentaceone-mediated cell death induction. The results showed that ramentaceone exhibited high antiproliferative activity toward breast cancer cells, in particular HER2-overexpressing breast cancer cells. The mode of cell death induced by ramentaceone was through apoptosis as determined by cytometric analysis of caspase activity and Annexin V staining. Apoptosis induction was found to be mediated by inhibition of PI3K/Akt signaling and through targeting its downstream anti-apoptotic effectors. Ramentaceone inhibited PI3-kinase activity, reduced the expression of the PI3K protein and inhibited the phosphorylation of the Akt protein in breast cancer cells. The expression of the anti-apoptotic Bcl-2 protein was decreased and the levels of the pro-apoptotic proteins, Bax and Bak, were elevated. Moreover, inhibition of PI3K and silencing of Akt expression increased the sensitivity of cells to ramentaceone-induced apoptosis. In conclusion, our results indicate that ramentaceone induces apoptosis in breast cancer cells through PI3K/Akt signaling inhibition. These findings suggest further investigation of ramentaceone as a potential therapeutic agent in breast cancer therapy, in particular HER2-positive breast cancer. PMID:26840401

  13. ARF6, PI3-kinase and host cell actin cytoskeleton in Toxoplasma gondii cell invasion

    SciTech Connect

    Vieira da Silva, Claudio; Alves da Silva, Erika; Costa Cruz, Mario; Chavrier, Philippe; Arruda Mortara, Renato

    2009-01-16

    Toxoplasma gondii infects a variety of different cell types in a range of different hosts. Host cell invasion by T. gondii occurs by active penetration of the host cell, a process previously described as independent of host actin polymerization. Also, the parasitophorous vacuole has been shown to resist fusion with endocytic and exocytic pathways of the host cell. ADP-ribosylation factor-6 (ARF6) belongs to the ARF family of small GTP-binding proteins. ARF6 regulates membrane trafficking and actin cytoskeleton rearrangements at the plasma membrane. Here, we have observed that ARF6 is recruited to the parasitophorous vacuole of tachyzoites of T. gondii RH strain and it also plays an important role in the parasite cell invasion with activation of PI3-kinase and recruitment of PIP{sub 2} and PIP{sub 3} to the parasitophorous vacuole of invading parasites. Moreover, it was verified that maintenance of host cell actin cytoskeleton integrity is important to parasite invasion.

  14. Gefitinib induces lung cancer cell autophagy and apoptosis via blockade of the PI3K/AKT/mTOR pathway

    PubMed Central

    ZHAO, ZHONG-QUAN; YU, ZHONG-YANG; LI, JIE; OUYANG, XUE-NONG

    2016-01-01

    Gefitinib is a selective inhibitor of the tyrosine kinase epidermal growth factor receptor, which inhibits tumor pathogenesis, metastasis and angiogenesis, as well as promoting apoptosis. Therefore, gefitinib presents an effective drug for the targeted therapy of lung cancer. However, the underlying mechanisms by which gefitinib induces lung cancer cell death remain unclear. To investigate the effects of gefitinib on lung cancer cells and the mechanism of such, the present study analyzed the effect of gefitinib on the autophagy, apoptosis and proliferation of the A549 and A549-gefitinib-resistant (GR) cell lines GR. The regulation of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/ mammalian target of rapamycin (mTOR) pathway was also investigated. Acridine orange staining revealed that gefitinib induced autophagy of A549 cells but not A549-GR cells. In addition, gefitinib promoted apoptosis and inhibited proliferation of A549 cells but not A549-GR cells. Furthermore, western blot analysis demonstrated that gefitinib treatment led to the downregulation of PI3K, AKT, pAKT, mTOR and phosphorylated-mTOR protein expression in A549 cells but not A549-GR cells. LY294002 blocked the PI3K/AKT/mTOR pathway and induced autophagy and apoptosis of A549 cells, however, no synergistic effect was observed following combined treatment with gefitinib and LY294002. In conclusion, the results of the present study indicate that gefitinib promotes autophagy and apoptosis of lung cancer cells via blockade of the PI3K/AKT/mTOR pathway, which leads to lung cancer cell death. PMID:27347100

  15. PREX2 promotes the proliferation, invasion and migration of pancreatic cancer cells by modulating the PI3K signaling pathway

    PubMed Central

    Yang, Jianyi; Gong, Xuejun; Ouyang, Lu; He, Wen; Xiao, Rou; Tan, Li

    2016-01-01

    Phosphatidylinositol-3,4,5-trisphosphate-dependent Rac exchanger factor 2 (PREX2) is a novel regulator of the small guanosine triphosphatase Rac, and has been observed to be implicated in human cancer by inhibiting the activity of phosphatase and tensin homolog (PTEN), thus upregulating the activity of the phosphoinositide 3-kinase (PI3K) signaling pathway. However, the exact role of PREX2 in pancreatic cancer has not been reported to date. In the present study, the expression levels of PREX2 were observed to be frequently increased in pancreatic cancer specimens compared with those in their matched adjacent normal tissues. In addition, PREX2 expression was also frequently upregulated in several pancreatic cancer cell lines, including AsPC-1, BxPC-3, PANC-1 and CFAPC-1, compared with that in the normal pancreatic epithelial cell line HPC-Y5. Overexpression of PREX2 significantly promoted the proliferation, invasion and migration of pancreatic cancer PANC-1 cells, while small interfering RNA-induced knockdown of PREX2 expression significantly inhibited the proliferation, invasion and migration of these cells. Investigation of the molecular mechanism revealed that the overexpression of PREX2 upregulated the phosphorylation levels of PTEN, indicating that the activity of PTEN was reduced, which further increased the phosphorylation levels of AKT, which indicated that the activity of the PI3K signaling pathway was upregulated. By contrast, knockdown of PREX2 upregulated the activity of PTEN and inhibited the activity of the PI3K signaling pathway. In conclusion, the present study demonstrated that PREX2 regulates the proliferation, invasion and migration of pancreatic cancer cells, probably at least via modulation of the activity of PTEN and the PI3K signaling pathway. PMID:27446408

  16. PI3K isoform dependence of PTEN-deficient tumors can be altered by the genetic context.

    PubMed

    Schmit, Fabienne; Utermark, Tamara; Zhang, Sen; Wang, Qi; Von, Thanh; Roberts, Thomas M; Zhao, Jean J

    2014-04-29

    There has been increasing interest in the use of isoform-selective inhibitors of phosphatidylinositide-3-kinase (PI3K) in cancer therapy. Using conditional deletion of the p110 catalytic isoforms of PI3K to predict sensitivity of cancer types to such inhibitors, we and others have demonstrated that tumors deficient of the phosphatase and tensin homolog (PTEN) are often dependent on the p110β isoform of PI3K. Because human cancers usually arise due to multiple genetic events, determining whether other genetic alterations might alter the p110 isoform requirements of PTEN-null tumors becomes a critical question. To investigate further the roles of p110 isoforms in PTEN-deficient tumors, we used a mouse model of ovarian endometrioid adenocarcinoma driven by concomitant activation of the rat sarcoma protein Kras, which is known to activate p110α, and loss of PTEN. In this model, ablation of p110β had no effect on tumor growth, whereas p110α ablation blocked tumor formation. Because ablation of PTEN alone is often p110β dependent, we wondered if the same held true in the ovary. Because PTEN loss alone in the ovary did not result in tumor formation, we tested PI3K isoform dependence in ovarian surface epithelium (OSE) cells deficient in both PTEN and p53. These cells were indeed p110β dependent, whereas OSEs expressing activated Kras with or without PTEN loss were p110α dependent. Furthermore, isoform-selective inhibitors showed a similar pattern of the isoform dependence in established Kras(G12D)/PTEN-deficient tumors. Taken together, our data suggest that, whereas in some tissues PTEN-null tumors appear to inherently depend on p110β, the p110 isoform reliance of PTEN-deficient tumors may be altered by concurrent mutations that activate p110α.

  17. Progesterone is neuroprotective against ischemic brain injury through its effects on the PI3K/Akt signaling pathway

    PubMed Central

    Ishrat, Tauheed; Sayeed, Iqbal; Atif, Fahim; Hua, Fang; Stein, Donald G.

    2012-01-01

    We tested the hypothesis that the phosphatidylinositol-3 kinase (PI3K/Akt) pathway mediates some of the neuroprotective effects of progesterone (PROG) after ischemic stroke. We examined whether PROG acting through the PI3K/Akt pathway could affect the expression of vascular endothelial growth factor (VEGF) and brain-derived neurotrophic factor (BDNF). Rats underwent permanent focal cerebral ischemia (pMCAO) by electro-coagulation and received intraperitoneal injections of PROG (8mg/kg) or vehicle at 1h post-occlusion and subcutaneous injections at 6, 24, and 48h. PAkt/Akt levels, apoptosis and apoptosis-related proteins (pBAD, BAD, caspase-3, and cleaved caspase-3) were analyzed by TUNEL assays, Western blotting and immunohistochemistry at 24h post-pMCAO. VEGF and BDNF were analyzed at 24, 72h and 14 days post-pMCAO with Western blots. Following pMCAO, PROG treatment significantly (p<0.05) reduced ischemic lesion size and edema. Treatment with PROG significantly (p<0.05) decreased VEGF at 24 and 72h but increased VEGF expression 14d after injury. The treatment also increased BDNF, and attenuated apoptosis by increasing Akt phosphorylation compared to vehicle-alone. The selective PI3K inhibitor Wortmannin compromised PROG-induced neuroprotective effects and reduced the elevation of pAkt levels in the ischemic penumbra. Our findings lead us to suggest that the PI3K/Akt pathway can play a role in mediating the neuroprotective effects of PROG after stroke by altering the expression of trophic factors in the brain. PMID:22450229

  18. PTEN Contributes to Profound PI3K/Akt Signaling Pathway Deregulation in Dystrophin-Deficient Dog Muscle

    PubMed Central

    Feron, Marie; Guevel, Laetitia; Rouger, Karl; Dubreil, Laurence; Arnaud, Marie-Claire; Ledevin, Mireille; Megeney, Lynn A.; Cherel, Yan; Sakanyan, Vehary

    2009-01-01

    Duchenne muscular dystrophy is the most common and severe form of muscular dystrophy, and although the genetic basis of this disease is well defined, the overall mechanisms that define its pathogenesis remain obscure. Alterations in individual signaling pathways have been described, but little information is available regarding their putative implications in Duchenne muscular dystrophy pathogenesis. Here, we studied the status of various major signaling pathways in the Golden Retriever muscular dystrophy dog that specifically reproduces the full spectrum of human pathology. Using antibody arrays, we found that Akt1, glycogen synthase kinase-3β (GSK3β), 70-kDa ribosomal protein S6 kinase (p70S6K), extracellular signal-regulated kinases 1/2, and p38δ and p38γ kinases all exhibited decreased phosphorylation in muscle from a 4-month-old animal with Golden Retriever muscular dystrophy, revealing a deep alteration of the phosphatidylinositol 3-kinase (PI3K)/Akt and mitogen-activated protein kinase pathways. Immunohistochemistry analysis revealed the presence of muscle fibers exhibiting a cytosolic accumulation of Akt1, GSK3β, and phosphatidylinositol-3,4,5-trisphosphate 3-phosphatase (PTEN), an enzyme counteracting PI3K-mediated Akt activation. Enzymatic assays established that these alterations in phosphorylation and expression levels were associated with decreased Akt and increased GSK3β and PTEN activities. PTEN/GSK3β-positive fibers were also observed in muscle sections from 3- and 36-month-old animals, indicating long-term PI3K/Akt pathway alteration. Collectively, our data suggest that increased PTEN expression and activity play a central role in PI3K/Akt/GSK3β and p70S6K pathway modulation, which could exacerbate the consequences of dystrophin deficiency. PMID:19264909

  19. Oocyte-specific deletion of Pten in mice reveals a stage-specific function of PTEN/PI3K signaling in oocytes in controlling follicular activation.

    PubMed

    Jagarlamudi, Krishna; Liu, Lian; Adhikari, Deepak; Reddy, Pradeep; Idahl, Annika; Ottander, Ulrika; Lundin, Eva; Liu, Kui

    2009-07-09

    Immature ovarian primordial follicles are essential for maintenance of the reproductive lifespan of female mammals. Recently, it was found that overactivation of the phosphatidylinositol 3-kinase (PI3K) signaling in oocytes of primordial follicles by an oocyte-specific deletion of Pten (phosphatase and tensin homolog deleted on chromosome ten), the gene encoding PI3K negative regulator PTEN, results in premature activation of the entire pool of primordial follicles, indicating that activation of the PI3K pathway in oocytes is important for control of follicular activation. To investigate whether PI3K signaling in oocytes of primary and further developed follicles also plays a role at later stages in follicular development and ovulation, we conditionally deleted the Pten gene from oocytes of primary and further developed follicles by using transgenic mice expressing zona pellucida 3 (Zp3) promoter-mediated Cre recombinase. Our results show that Pten was efficiently deleted from oocytes of primary and further developed follicles, as indicated by the elevated phosphorylation of the major PI3K downstream component Akt. However, follicular development was not altered and oocyte maturation was also normal, which led to normal fertility with unaltered litter size in the mutant mice. Our data indicate that properly controlled PTEN/PI3K-Akt signaling in oocytes is essential for control of the development of primordial follicles whereas overactivation of PI3K signaling in oocytes does not appear to affect the development of growing follicles. This suggests that there is a stage-specific function of PTEN/PI3K signaling in mouse oocytes that controls follicular activation.

  20. Exercise improves the dilatation function of mesenteric arteries in postmyocardial infarction rats via a PI3K/Akt/eNOS pathway-mediated mechanism.

    PubMed

    Wang, Youhua; Wang, Shengpeng; Wier, W Gil; Zhang, Quanjiang; Jiang, Hongke; Li, Qiuxia; Chen, Shengfeng; Tian, Zhenjun; Li, Youyou; Yu, Xiaojiang; Zhao, Ming; Liu, Jinjun; Yang, Jing; Zhang, Jing; Zang, Weijin

    2010-12-01

    Myocardial infarction (MI) has been shown to induce endothelial dysfunction in peripheral resistance arteries and thus increase peripheral resistance. This study was designed to investigate the underlying mechanisms of post-MI-related dysfunctional dilatation of peripheral resistance arteries and, furthermore, to examine whether exercise may restore dysfunctional dilatation of peripheral resistance arteries. Adult male Sprague-Dawley rats were divided into three groups: sham-operated, MI, and MI + exercise. Ultrastructure and relaxation function of the mesenteric arteries, as well as phosphatidylinositol-3 kinase (PI3K), Akt kinases (Akt), endothelial nitric oxide synthase (eNOS) activity, and phosphorylation of PI3K, Akt, and eNOS by ACh were determined. Post-MI rats exhibited pronounced ultrastructural changes in mesenteric artery endothelial cells and endothelial dysfunction. In addition, the activities of PI3K, Akt, and eNOS, and their phosphorylation by ACh were significantly attenuated in mesenteric arteries (P < 0.05-0.01). After 8 wk of exercise, not only did endothelial cells appeared more normal in structure, but also ameliorated post-MI-associated mesenteric arterial dysfunction, which were accompanied by elevated activities of PI3K, Akt, and eNOS, and their phosphorylation by ACh (P < 0.05-0.01). Importantly, inhibition of either PI3K or eNOS attenuated exercise-induced restoration of the dilatation function and blocked PI3K, Akt, and eNOS phosphorylation by ACh in the mesenteric arteries. These data demonstrate that MI induces dysfunctional dilation of peripheral resistance arteries by degradation of endothelial structural integrity and attenuating PI3K-Akt-eNOS signaling. Exercise may restore dilatation function of peripheral resistance arteries by protecting endothelial structural integrity and increasing PI3K-Akt-eNOS signaling cascades.

  1. The p110δ subunit of PI3K regulates bone marrow-derived eosinophil trafficking and airway eosinophilia in allergen-challenged mice

    PubMed Central

    Kang, Bit Na; Ha, Sung Gil; Ge, Xiao Na; Reza Hosseinkhani, M.; Bahaie, Nooshin S.; Greenberg, Yana; Blumenthal, Malcolm N.; Puri, Kamal D.; Rao, Savita P.

    2012-01-01

    Trafficking and recruitment of eosinophils during allergic airway inflammation is mediated by the phosphatidylinositol 3-kinase (PI3K) family of signaling molecules. The role played by the p110δ subunit of PI3K (PI3K p110δ) in regulating eosinophil trafficking and recruitment was investigated using a selective pharmacological inhibitor (IC87114). Treatment with the PI3K p110δ inhibitor significantly reduced murine bone marrow-derived eosinophil (BM-Eos) adhesion to VCAM-1 as well as ICAM-1 and inhibited activation-induced changes in cell morphology associated with reduced Mac-1 expression and aberrant cell surface localization/distribution of Mac-1 and α4. Infused BM-Eos demonstrated significantly decreased rolling and adhesion in inflamed cremaster muscle microvessels of mice treated with IC87114 compared with vehicle-treated mice. Furthermore, inhibition of PI3K p110δ significantly attenuated eotaxin-1-induced BM-Eos migration and prevented eotaxin-1-induced changes in the cytoskeleton and cell morphology. Knockdown of PI3K p110δ with siRNA in BM-Eos resulted in reduced rolling, adhesion, and migration, as well as inhibition of activation-induced changes in cell morphology, validating its role in regulating trafficking and migration. Finally, in a mouse model of cockroach antigen-induced allergic airway inflammation, oral administration of the PI3K p110δ inhibitor significantly inhibited airway eosinophil recruitment, resulting in attenuation of airway hyperresponsiveness in response to methacholine, reduced mucus secretion, and expression of proinflammatory molecules (found in inflammatory zone-1 and intelectin-1). Overall, these findings indicate the important role played by PI3K p110δ in mediating BM-Eos trafficking and migration by regulating adhesion molecule expression and localization/distribution as well as promoting changes in cell morphology that favor recruitment during inflammation. PMID:22427531

  2. Estrogen increases Nrf2 activity through activation of the PI3K pathway in MCF-7 breast cancer cells

    SciTech Connect

    Wu, Juanjuan; Williams, Devin; Walter, Grant A.; Thompson, Winston E.; Sidell, Neil

    2014-11-01

    The actions of the transcription factor Nuclear factor erythroid 2-related factor (Nrf2) in breast cancer have been shown to include both pro-oncogenic and anti-oncogenic activities which is influenced, at least in part, by the hormonal environment. However, direct regulation of Nrf2 by steroid hormones (estrogen and progesterone) has received only scant attention. Nrf2 is known to be regulated by its cytosolic binding protein, Kelch-like ECH-associated protein 1 (Keap1), and by a Keap1-independent mechanism involving a series of phosphorylation steps mediated by phosphatidylinositol 3-kinase (PI3K) and glycogen synthase kinase 3 beta (GSK3β). Here, we report that estrogen (E2) increases Nrf2 activity in MCF7 breast cancer cells through activation of the PI3K/GSK3β pathway. Utilizing antioxidant response element (ARE)-containing luciferase reporter constructs as read-outs for Nrf2 activity, our data indicated that E2 increased ARE activity >14-fold and enhanced the action of the Nrf2 activators, tertiary butylhydroquinone (tBHQ) and sulforaphane (Sul) 4 to 9 fold compared with cells treated with tBHQ or Sul as single agents. This activity was shown to be an estrogen receptor-mediated phenomenon and was antagonized by progesterone. In addition to its action on the reporter constructs, mRNA and protein levels of heme oxygenase 1, an endogenous target gene of Nrf2, was markedly upregulated by E2 both alone and in combination with tBHQ. Importantly, E2-induced Nrf2 activation was completely suppressed by the PI3K inhibitors LY294002 and Wortmannin while the GSK3β inhibitor CT99021 upregulated Nrf2 activity. Confirmation that E2 was, at least partly, acting through the PI3K/GSK3β pathway was indicated by our finding that E2 increased the phosphorylation status of both GSK3β and Akt, a well-characterized downstream target of PI3K. Together, these results demonstrate a novel mechanism by which E2 can regulate Nrf2 activity in estrogen receptor-positive breast cancer

  3. Adenosine A{sub 2A} receptor-dependent proliferation of pulmonary endothelial cells is mediated through calcium mobilization, PI3-kinase and ERK1/2 pathways

    SciTech Connect

    Ahmad, Aftab; Schaack, Jerome B.; White, Carl W.; Ahmad, Shama

    2013-05-10

    Highlights: •A{sub 2A} receptor-induced pulmonary endothelial growth is mediated by PI3K and ERK1/2. •Cytosolic calcium mobilization is also critical for pulmonary endothelial growth. •Effectors of A{sub 2A} receptor, like tyrosine kinases and cAMP increase PI3K/Akt signaling. •Activation of A{sub 2A} receptor can contribute to vascular remodeling. -- Abstract: Hypoxia and HIF-2α-dependent A{sub 2A} receptor expression and activation increase proliferation of human lung microvascular endothelial cells (HLMVECs). This study was undertaken to investigate the signaling mechanisms that mediate the proliferative effects of A{sub 2A} receptor. A{sub 2A} receptor-mediated proliferation of HLMVECs was inhibited by intracellular calcium chelation, and by specific inhibitors of ERK1/2 and PI3-kinase (PI3K). The adenosine A{sub 2A} receptor agonist CGS21680 caused intracellular calcium mobilization in controls and, to a greater extent, in A{sub 2A} receptor-overexpressing HLMVECs. Adenoviral-mediated A{sub 2A} receptor overexpression as well as receptor activation by CGS21680 caused increased PI3K activity and Akt phosphorylation. Cells overexpressing A{sub 2A} receptor also manifested enhanced ERK1/2 phosphorylation upon CGS21680 treatment. A{sub 2A} receptor activation also caused enhanced cAMP production. Likewise, treatment with 8Br-cAMP increased PI3K activity. Hence A{sub 2A} receptor-mediated cAMP production and PI3K and Akt phosphorylation are potential mediators of the A{sub 2A}-mediated proliferative response of HLMVECs. Cytosolic calcium mobilization and ERK1/2 phosphorylation are other critical effectors of HLMVEC proliferation and growth. These studies underscore the importance of adenosine A{sub 2A} receptor in activation of survival and proliferative pathways in pulmonary endothelial cells that are mediated through PI3K/Akt and ERK1/2 pathways.

  4. PI-103 and Quercetin Attenuate PI3K-AKT Signaling Pathway in T- Cell Lymphoma Exposed to Hydrogen Peroxide

    PubMed Central

    Maurya, Akhilendra Kumar; Vinayak, Manjula

    2016-01-01

    Phosphatidylinositol 3 kinase—protein kinase B (PI3K-AKT) pathway has been considered as major drug target site due to its frequent activation in cancer. AKT regulates the activity of various targets to promote tumorigenesis and metastasis. Accumulation of reactive oxygen species (ROS) has been linked to oxidative stress and regulation of signaling pathways for metabolic adaptation of tumor microenvironment. Hydrogen peroxide (H2O2) in this context is used as ROS source for oxidative stress preconditioning. Antioxidants are commonly considered to be beneficial to reduce detrimental effects of ROS and are recommended as dietary supplements. Quercetin, a ubiquitous bioactive flavonoid is a dietary component which has attracted much of interest due to its potential health-promoting effects. Present study is aimed to analyze PI3K-AKT signaling pathway in H2O2 exposed Dalton’s lymphoma ascite (DLA) cells. Further, regulation of PI3K-AKT pathway by quercetin as well as PI-103, an inhibitor of PI3K was analyzed. Exposure of H2O2 (1mM H2O2 for 30min) to DLA cells caused ROS accumulation and resulted in increased phosphorylation of PI3K and downstream proteins PDK1 and AKT (Ser-473 and Thr-308), cell survival factors BAD and ERK1/2, as well as TNFR1. However, level of tumor suppressor PTEN was declined. Both PI-103 & quercetin suppressed the enhanced level of ROS and significantly down-regulated phosphorylation of AKT, PDK1, BAD and level of TNFR1 as well as increased the level of PTEN in H2O2 induced lymphoma cells. The overall result suggests that quercetin and PI3K inhibitor PI-103 attenuate PI3K-AKT pathway in a similar mechanism. PMID:27494022

  5. Rationale-based therapeutic combinations with PI3K inhibitors in cancer treatment

    PubMed Central

    Castel, Pau; Toska, Eneda; Zumsteg, Zachary S; Carmona, F Javier; Elkabets, Moshe; Bosch, Ana; Scaltriti, Maurizio

    2014-01-01

    The PI3K/AKT/mTOR signaling is important for cell proliferation, survival, and metabolism. Hyperactivation of this pathway is one of the most common signaling abnormalities observed in cancer and a substantial effort has recently been made to develop molecules targeting this signaling cascade. However, it is becoming evident that PI3K inhibitors used as single agents do not elicit dramatic or durable responses. Given the numerous mechanisms mediating intrinsic and acquired resistance to these agents, hypothesis-based combinatorial strategies are probably needed to fully exploit their antitumor activity. In the first part of this review, we briefly dissect the PI3K/AKT/mTOR axis and list the most advanced compounds targeting different nodes of this cascade. The second part focuses on what we believe to be the most promising rationale-based therapeutic combinations with PI3K/AKT/mTOR inhibitors in solid tumors, with special emphasis on breast cancer. PMID:27308344

  6. P-REX1 creates a positive feedback loop to activate growth factor receptor, PI3K/AKT, and MEK/ERK signaling in breast cancer

    PubMed Central

    Dillon, Lloye M.; Bean, Jennifer R.; Yang, Wei; Shee, Kevin; Symonds, Lynn K.; Balko, Justin M.; McDonald, W. Hayes; Liu, Shuying; Gonzalez-Angulo, Ana M.; Mills, Gordon B.; Arteaga, Carlos L.; Miller, Todd W.

    2014-01-01

    Phosphatidylinositol 3-kinase (PI3K) promotes cancer cell survival, migration, growth, and proliferation by generating phosphatidylinositol 3,4,5-trisphosphate (PIP3) in the inner leaflet of the plasma membrane. PIP3 recruits pleckstrin homology (PH) domain-containing proteins to the membrane to activate oncogenic signaling cascades. Anti-cancer therapeutics targeting the PI3K/AKT/mTOR pathway are in clinical development. In a mass spectrometric screen to identify PIP3-regulated proteins in breast cancer cells, levels of the Rac activator PIP3-dependent Rac exchange factor 1 (P-REX1) increased in response to PI3K inhibition, and decreased upon loss of the PI3K antagonist PTEN. P-REX1 mRNA and protein levels were positively correlated with ER expression, and inversely correlated with PI3K pathway activation in breast tumors as assessed by gene expression and phosphoproteomic analyses. P-REX1 increased activation of Rac1, PI3K/AKT, and MEK/ERK signaling in a PTEN-independent manner, and promoted cell and tumor viability. Loss of P-REX1 or inhibition of Rac suppressed PI3K/AKT and MEK/ERK, and decreased viability. P-REX1 also promoted insulin-like growth factor-1 receptor (IGF-1R) activation, suggesting that P-REX1 provides positive feedback to activators upstream of PI3K. In support of a model where PIP3-driven P-REX1 promotes both PI3K/AKT and MEK/ERK signaling, high levels of P-REX1 mRNA (but not phospho-AKT or a transcriptomic signature of PI3K activation) were predictive of sensitivity to PI3K inhibitors among breast cancer cell lines. P-REX1 expression was highest in ER+ breast tumors compared to many other cancer subtypes, suggesting that neutralizing the P-REX1/Rac axis may provide a novel therapeutic approach to selectively abrogate oncogenic signaling in breast cancer cells. PMID:25284585

  7. p85 regulatory subunit of PI3K mediates cAMP-PKA and estrogens biological effects on growth and survival.

    PubMed

    Cosentino, C; Di Domenico, M; Porcellini, A; Cuozzo, C; De Gregorio, G; Santillo, M R; Agnese, S; Di Stasio, R; Feliciello, A; Migliaccio, A; Avvedimento, E V

    2007-03-29

    Cyclic adenosine 3'5' monophosphate (cAMP) and protein kinase A (PKA) cooperate with phosphatidylinositol 3' kinase (PI3K) signals in the control of growth and survival. To determine the molecular mechanism(s) involved, we identified and mutagenized a specific serine (residue 83) in p85alpha(PI3K), which is phosphorylated in vivo and in vitro by PKA. Expression of p85alpha(PI3K) mutants (alanine or aspartic substitutions) significantly altered the biological responses of the cells to cAMP. cAMP protection from anoikis was reduced in cells expressing the alanine version p85alpha(PI3K). These cells did not arrest in G1 in the presence of cAMP, whereas cells expressing the aspartic mutant p85D accumulated in G1 even in the absence of cAMP. S phase was still efficiently inhibited by cAMP in cells expressing both mutants. The binding of PI3K to Ras p21 was greatly reduced in cells expressing p85A in the presence or absence of cAMP. Conversely, expression of the aspartic mutant stimulated robustly the binding of PI3K to p21 Ras in the presence of cAMP. Mutation in the Ser 83 inhibited cAMP, but not PDGF stimulation of PI3K. Conversely, the p85D aspartic mutant amplified cAMP stimulation of PI3K activity. Phosphorylation of Ser 83 by cAMP-PKA in p85alpha(PI3K) was also necessary for estrogen signaling as expression of p85A or p85D mutants inhibited or amplified, respectively, the binding of estrogen receptor to p85alpha and AKT phosphorylation induced by estrogens. The data presented indicate that: (1) phosphorylation of Ser 83 in p85alpha(PI3K) is critical for cAMP-PKA induced G1 arrest and survival in mouse 3T3 fibroblasts; (2) this site is necessary for amplification of estrogen signals by cAMP-PKA and related receptors. Finally, these data suggest a general mechanism of PI3K regulation by cAMP, operating in various cell types and under different conditions. PMID:17016431

  8. Glutathione biosynthesis is a metabolic vulnerability in PI3K/Akt-driven breast cancer

    PubMed Central

    Lien, Evan C.; Lyssiotis, Costas A.; Juvekar, Ashish; Hu, Hai; Asara, John M.; Cantley, Lewis C.; Toker, Alex

    2016-01-01

    Cancer cells often select for mutations that enhance signaling through pathways that promote anabolic metabolism1. Although the PI3K/Akt signaling pathway, which is frequently dysregulated in breast cancer2, is a well-established regulator of central glucose metabolism and aerobic glycolysis3,4, its regulation of other metabolic processes required for tumor growth is not well defined. Here we report that in mammary epithelial cells, oncogenic PI3K/Akt stimulates glutathione (GSH) biosynthesis by stabilizing and activating Nrf2 to up-regulate the GSH biosynthetic genes. Increased Nrf2 stability is dependent on the Akt-mediated accumulation of p21Cip1/WAF1 and GSK-3 inhibition. Consistently, in human breast tumors, up-regulation of Nrf2 targets is associated with PI3K pathway mutation status and oncogenic Akt activation. Elevated GSH biosynthesis is required for PI3K/Akt-driven resistance to oxidative stress, initiation of tumor spheroids, and anchorage-independent growth. Furthermore, inhibition of GSH biosynthesis with buthionine sulfoximine (BSO) synergizes with cisplatin (CDDP) to selectively induce tumor regression in PI3K pathway mutant breast cancer cells, both in vitro and in vivo. Our findings provide insight into GSH biosynthesis as a metabolic vulnerability associated with PI3K pathway mutant breast cancers. PMID:27088857

  9. RICTOR involvement in the PI3K/AKT pathway regulation in melanocytes and melanoma

    PubMed Central

    Laugier, Florence; Finet-Benyair, Adeline; André, Jocelyne; Rachakonda, P. Sivaramakrishna; Kumar, Rajiv; Bensussan, Armand; Dumaz, Nicolas

    2015-01-01

    Several studies have highlighted the importance of the PI3K pathway in melanocytes and its frequent over-activation in melanoma. However, little is known about regulation of the PI3K pathway in melanocytic cells. We showed that normal human melanocytes are less sensitive to selective PI3K or mTOR inhibitors than to dual PI3K/mTOR inhibitors. The resistance to PI3K inhibitor was due to a rapid AKT reactivation limiting the inhibitor effect on proliferation. Reactivation of AKT was linked to a feedback mechanism involving the mTORC2 complex and in particular its scaffold protein RICTOR. RICTOR overexpression in melanocytes disrupted the negative feedback, activated the AKT pathway and stimulated clonogenicity highlighting the importance of this feedback to restrict melanocyte proliferation. We found that the RICTOR locus is frequently amplified and overexpressed in melanoma and that RICTOR over-expression in NRAS-transformed melanocytes stimulates their clonogenicity, demonstrating that RICTOR amplification can cooperate with NRAS mutation to stimulate melanoma proliferation. These results show that RICTOR plays a central role in PI3K pathway negative feedback in melanocytes and that its deregulation could be involved in melanoma development. PMID:26356562

  10. RICTOR involvement in the PI3K/AKT pathway regulation in melanocytes and melanoma.

    PubMed

    Laugier, Florence; Finet-Benyair, Adeline; André, Jocelyne; Rachakonda, P Sivaramakrishna; Kumar, Rajiv; Bensussan, Armand; Dumaz, Nicolas

    2015-09-29

    Several studies have highlighted the importance of the PI3K pathway in melanocytes and its frequent over-activation in melanoma. However, little is known about regulation of the PI3K pathway in melanocytic cells. We showed that normal human melanocytes are less sensitive to selective PI3K or mTOR inhibitors than to dual PI3K/mTOR inhibitors. The resistance to PI3K inhibitor was due to a rapid AKT reactivation limiting the inhibitor effect on proliferation. Reactivation of AKT was linked to a feedback mechanism involving the mTORC2 complex and in particular its scaffold protein RICTOR. RICTOR overexpression in melanocytes disrupted the negative feedback, activated the AKT pathway and stimulated clonogenicity highlighting the importance of this feedback to restrict melanocyte proliferation. We found that the RICTOR locus is frequently amplified and overexpressed in melanoma and that RICTOR over-expression in NRAS-transformed melanocytes stimulates their clonogenicity, demonstrating that RICTOR amplification can cooperate with NRAS mutation to stimulate melanoma proliferation. These results show that RICTOR plays a central role in PI3K pathway negative feedback in melanocytes and that its deregulation could be involved in melanoma development.

  11. Periostin Promotes Atrioventricular Mesenchyme Matrix Invasion and Remodeling Mediated by Integrin Signaling through Rho/PI 3-Kinase

    PubMed Central

    Butcher, Jonathan T.; Norris, Russell A.; Hoffman, Stanley; Mjaatvedt, Corey H.; Markwald, Roger R.

    2007-01-01

    Recent evidence suggests that extracellular matrix components may play a signaling role in embryonic valve development. We have previously identified the spatiotemporal expression patterns of periostin in developing valves, but its function during this process is largely unknown. To evaluate the functional role periostin plays during valvulogenesis, two separate three-dimensional culture assay systems, which model chick atrioventricular cushion development, were employed. These assays demonstrated that cushion mesenchymal cells adhered and spread on purified periostin in a dose responsive manner, similar to collagen I and fibronectin via αvβ3 and β1 integrin pairs. Periostin overexpression resulted in enhanced mesenchyme invasion through 3D collagen gels and increased matrix compaction. This invasion was dependent on αvβ3 more than β1 integrin signaling, and was mediated differentially by Rho kinase and PI 3-kinase. Both matrix invasion and compaction were associated with a colocalization of periostin and β1 integrin expression to migratory cell phenotype in both surface and deep cells. The Rho/PI 3-kinase pathway also differentially mediated matrix compaction. Both Rho and PI 3-kinase were involved in normal cushion mesenchyme matrix compaction, but only PI 3-kinase was required for the enhanced matrix compaction due to periostin. Taken together, these results highlight periostin as a mediator of matrix remodeling by cushion mesenchyme towards a mature valve structure. PMID:17070513

  12. Heterozygous splice mutation in PIK3R1 causes human immunodeficiency with lymphoproliferation due to dominant activation of PI3K

    PubMed Central

    Lucas, Carrie L.; Zhang, Yu; Venida, Anthony; Wang, Ying; Hughes, Jason; McElwee, Joshua; Butrick, Morgan; Matthews, Helen; Price, Susan; Biancalana, Matthew; Wang, Xiaochuan; Richards, Michael; Pozos, Tamara; Barlan, Isil; Ozen, Ahmet; Rao, V. Koneti; Su, Helen C.

    2014-01-01

    Class IA phosphatidylinositol 3-kinases (PI3K), which generate PIP3 as a signal for cell growth and proliferation, exist as an intracellular complex of a catalytic subunit bound to a regulatory subunit. We and others have previously reported that heterozygous mutations in PIK3CD encoding the p110δ catalytic PI3K subunit cause a unique disorder termed p110δ-activating mutations causing senescent T cells, lymphadenopathy, and immunodeficiency (PASLI) disease. We report four patients from three families with a similar disease who harbor a recently reported heterozygous splice site mutation in PIK3R1, which encodes the p85α, p55α, and p50α regulatory PI3K subunits. These patients suffer from recurrent sinopulmonary infections and lymphoproliferation, exhibit hyperactive PI3K signaling, and have prominent expansion and skewing of peripheral blood CD8+ T cells toward terminally differentiated senescent effector cells with short telomeres. The PIK3R1 splice site mutation causes skipping of an exon, corresponding to loss of amino acid residues 434–475 in the inter-SH2 domain. The mutant p85α protein is expressed at low levels in patient cells and activates PI3K signaling when overexpressed in T cells from healthy subjects due to qualitative and quantitative binding changes in the p85α–p110δ complex and failure of the C-terminal region to properly inhibit p110δ catalytic activity. PMID:25488983

  13. Low-Dose Endothelial Monocyte-Activating Polypeptide-II Increases Blood-Tumor Barrier Permeability by Activating the RhoA/ROCK/PI3K Signaling Pathway.

    PubMed

    Li, Zhen; Liu, Xiao-Bai; Liu, Yun-Hui; Xue, Yi-Xue; Liu, Jing; Teng, Hao; Xi, Zhuo; Yao, Yi-Long

    2016-06-01

    Previous studies have demonstrated that low-dose endothelial monocyte-activating polypeptide-II (EMAP-II) can increase blood-tumor barrier (BTB) permeability via both paracellular and transcellular pathways. In addition, we revealed that the RhoA/Rho kinase (ROCK) signaling pathway is involved in EMAP-II-induced BTB opening. This study further investigated the exact mechanisms by which the RhoA/ROCK signaling pathway affects EMAP-II-induced BTB hyperpermeability. In an in vitro BTB model, low-dose EMAP-II significantly activated phosphatidylinositol-3-kinase (PI3K) in rat brain microvascular endothelial cells (RBMECs) at 0.75 h. Pretreatment with RhoA inhibitor C3 exoenzyme or ROCK inhibitor Y-27632 completely blocked EMAP-II-induced activation of PI3K. PKC-α/β inhibitor GÖ6976 pretreatment caused no change in EMAP-II-induced activation of PI3K. Besides, pretreatment with LY294002, a specific inhibitor of PI3K, did not affect EMAP-II-induced activation of PKC-α/β. Furthermore, LY294002 pretreatment significantly diminished EMAP-II-induced changes in BTB permeability, phosphorylation of myosin light chain and cofilin, expression and distribution of tight junction-associated protein ZO-1, and actin cytoskeleton arrangement in RBMECs. In summary, this study demonstrates that low-dose EMAP-II can increase BTB permeability by activating the RhoA/ROCK/PI3K signaling pathway.

  14. Effects of low-intensity pulsed ultrasound on integrin-FAK-PI3K/Akt mechanochemical transduction in rabbit osteoarthritis chondrocytes.

    PubMed

    Cheng, Kai; Xia, Peng; Lin, Qiang; Shen, Shihao; Gao, Mingxia; Ren, Shasha; Li, Xueping

    2014-07-01

    The effect of low-intensity pulsed ultrasound (LIPUS) on extracellular matrix (ECM) production via modulation of the integrin/focal adhesion kinase (FAK)/phosphatidylinositol 3-kinase (PI3K)/Akt pathway has been investigated in previous studies in normal chondrocytes, but not in osteoarthritis (OA). Therefore, we investigated the LIPUS-induced integrin β1/FAK/PI3K/Akt mechanochemical transduction pathway in a single study in rabbit OA chondrocytes. Normal and OA chondrocytes were exposed to LIPUS, and mRNA and protein expression of cartilage, metalloproteinases and integrin-FAK-PI3K/Akt signal pathway-related genes was determined by quantitative reverse transcription polymerase chain reaction and Western blotting, respectively. Compared with levels in normal chondrocytes, expression levels of ECM-related genes were significantly lower in OA chondrocytes and those of metalloproteinase-related genes were significantly higher. In addition, integrin β1 gene expression and the phosphorylation of FAK, PI3K and Akt were significantly higher in OA chondrocytes. The expression of all tested genes was significantly increased except for that of metalloproteinase, which was significantly decreased in the LIPUS-treated OA group compared to the untreated OA group. LIPUS may affect the integrin-FAK-PI3K/Akt mechanochemical transduction pathway and alter ECM production by OA chondrocytes. Our findings will aid the future development of a treatment or even cure for OA.

  15. Activation of PI3K/Akt signaling has a dominant negative effect on IL-12 production by macrophages infected with Leishmania amazonensis promastigotes

    PubMed Central

    Ruhland, Aaron; Kima, Peter E.

    2009-01-01

    Infection of macrophages with Leishmania parasites does not result in the production of IL-12. In addition, infection with Leishmania suppresses IL-12 production elicited by otherwise potent activators of IL-12. We provide evidence that engagement of phosphatidyl inositol-3 kinase (PI3K) signaling during Leishmania amazonensis infection leads to the prevention of IL-12 p70 production at the level of transcription of its p40 subunit in bone marrow derived macrophages (BMDMϕ). Inhibition of PI3K signaling with specific inhibitors of PI3K or the downstream kinase Akt, reverses the IL-12 blockade. Although the MAP kinase ERK (p44 and p42) was transiently activated by infection with L. amazonensis, inhibition of MEK, the kinase upstream of ERK, with PD98059, did not reverse the blockade of IL-12. Furthermore, inhibition of the other MAP kinases JNK and p38 as well as treatment of cells with pertussis toxin that blocks G protein mediated signaling, did not reverse the prevention of IL-12 production by Leishmania infection. Interestingly, activation of PI3K/Akt signaling had differential effects on ERK and p38 activation. Taken together we propose that infection of BMDMϕ with Leishmania promastigotes activates both positive and negative signaling pathways that control IL-12 production. PI3K signaling activated by the infection is the negative signaling pathway that prevents IL-12 production. PMID:19186178

  16. Activation of PI3K/Akt signaling has a dominant negative effect on IL-12 production by macrophages infected with Leishmania amazonensis promastigotes.

    PubMed

    Ruhland, Aaron; Kima, Peter E

    2009-05-01

    Infection of macrophages with Leishmania parasites does not result in the production of IL-12. In addition, infection with Leishmania suppresses IL-12 production elicited by otherwise potent activators of IL-12. We provide evidence that engagement of phosphatidyl inositol-3 kinase (PI3K) signaling during Leishmania amazonensis infection leads to the prevention of IL-12 p70 production at the level of transcription of its p40 subunit in bone marrow derived macrophages (BMDMPhi). Inhibition of PI3K signaling with specific inhibitors of PI3K or the downstream kinase Akt, reverses the IL-12 blockade. Although the MAP kinase ERK (p44 and p42) was transiently activated by infection with L. amazonensis, inhibition of MEK, the kinase upstream of ERK, with PD98059, did not reverse the blockade of IL-12. Furthermore, inhibition of the other MAP kinases JNK and p38 as well as treatment of cells with pertussis toxin that blocks G protein mediated signaling, did not reverse the prevention of IL-12 production by Leishmania infection. Interestingly, activation of PI3K/Akt signaling had differential effects on ERK and p38 activation. Taken together we propose that infection of BMDMPhi with Leishmania promastigotes activates both positive and negative signaling pathways that control IL-12 production. PI3K signaling activated by the infection is the negative signaling pathway that prevents IL-12 production.

  17. Suppression of Virulent Porcine Epidemic Diarrhea Virus Proliferation by the PI3K/Akt/GSK-3α/β Pathway.

    PubMed

    Kong, Ning; Wu, Yongguang; Meng, Qiong; Wang, Zhongze; Zuo, Yewen; Pan, Xi; Tong, Wu; Zheng, Hao; Li, Guoxin; Yang, Shen; Yu, Hai; Zhou, En-Min; Shan, Tongling; Tong, Guangzhi

    2016-01-01

    Porcine epidemic diarrhea virus (PEDV) has recently caused high mortality in suckling piglets with subsequent large economic losses to the swine industry. Many intracellular signaling pathways, including the phosphatidylinositol 3-kinase (PI3K)/Akt pathway, are activated by viral infection. The PI3K/Akt pathway is an important cellular pathway that has been shown to be required for virus replication. In the present study, we found that the PEDV JS-2013 strain activated Akt in Vero cells at early (5-15 min) and late stages (8-10 h) of infection. Inhibiting PI3K, an upstream activator of Akt, enhanced PEDV replication. Inhibiting GSK-3α/β, one of the downstream effectors of PI3K/Akt pathway and regulated by Akt during PEDV infected Vero cells, also enhanced PEDV replication. Collectively, our data suggest that PI3K/Akt/GSK-3α/β signaling pathway is activated by PEDV and functions in inhibiting PEDV replication. PMID:27560518

  18. Suppression of Virulent Porcine Epidemic Diarrhea Virus Proliferation by the PI3K/Akt/GSK-3α/β Pathway

    PubMed Central

    Kong, Ning; Wu, Yongguang; Meng, Qiong; Wang, Zhongze; Zuo, Yewen; Pan, Xi; Tong, Wu; Zheng, Hao; Li, Guoxin; Yang, Shen; Yu, Hai; Zhou, En-min; Shan, Tongling; Tong, Guangzhi

    2016-01-01

    Porcine epidemic diarrhea virus (PEDV) has recently caused high mortality in suckling piglets with subsequent large economic losses to the swine industry. Many intracellular signaling pathways, including the phosphatidylinositol 3-kinase (PI3K)/Akt pathway, are activated by viral infection. The PI3K/Akt pathway is an important cellular pathway that has been shown to be required for virus replication. In the present study, we found that the PEDV JS-2013 strain activated Akt in Vero cells at early (5–15 min) and late stages (8–10 h) of infection. Inhibiting PI3K, an upstream activator of Akt, enhanced PEDV replication. Inhibiting GSK-3α/β, one of the downstream effectors of PI3K/Akt pathway and regulated by Akt during PEDV infected Vero cells, also enhanced PEDV replication. Collectively, our data suggest that PI3K/Akt/GSK-3α/β signaling pathway is activated by PEDV and functions in inhibiting PEDV replication. PMID:27560518

  19. Differential Water Thermodynamics Determine PI3K-Beta/Delta Selectivity for Solvent-Exposed Ligand Modifications.

    PubMed

    Robinson, Daniel; Bertrand, Thomas; Carry, Jean-Christophe; Halley, Frank; Karlsson, Andreas; Mathieu, Magali; Minoux, Hervé; Perrin, Marc-Antoine; Robert, Benoit; Schio, Laurent; Sherman, Woody

    2016-05-23

    Phosphoinositide 3-kinases (PI3Ks) are involved in important cellular functions and represent desirable targets for drug discovery efforts, especially related to oncology; however, the four PI3K subtypes (α, β, γ, and δ) have highly similar binding sites, making the design of selective inhibitors challenging. A series of inhibitors with selectivity toward the β subtype over δ resulted in compound 3(S), which has entered a phase I/Ib clinical trial for patients with advanced PTEN-deficient cancer. Interestingly, X-ray crystallography revealed that the modifications making inhibitor 3(S) and related compounds selective toward the β-isoform do not interact directly with either PI3Kβ or PI3Kδ, thereby confounding rationalization of the SAR. Here, we apply explicit solvent molecular dynamics and solvent thermodynamic analysis using WaterMap in an effort to understand the unusual affinity and selectivity trends. We find that differences in solvent energetics and water networks, which are modulated upon binding of different ligands, explain the experimental affinity and selectivity trends. This study highlights the critical role of water molecules in molecular recognition and the importance of considering water networks in drug discovery efforts to rationalize and improve selectivity. PMID:27144736

  20. Identification of differential PI3K pathway target dependencies in T-cell acute lymphoblastic leukemia through a large cancer cell panel screen.

    PubMed

    Lynch, James T; McEwen, Robert; Crafter, Claire; McDermott, Ultan; Garnett, Mathew J; Barry, Simon T; Davies, Barry R

    2016-04-19

    Selective phosphoinositide 3-kinase (PI3K)/AKT/mTOR inhibitors are currently under evaluation in clinical studies. To identify tumor types that are sensitive to PI3K pathway inhibitors we screened compounds targeting PI3Kα/δ (AZD8835), PI3Kβ/δ (AZD8186), AKT (AZD5363) and mTORC1/2 (AZD2014) against a cancer cell line panel (971 cell lines). There was an enrichment of hematological malignancies that were sensitive to AKT and mTOR inhibition, with the greatest degree of sensitivity observed in T-cell acute lymphoblastic leukemia (T-ALL). We found that all NOTCH mutant T-ALL cell lines were sensitive to AKT and mTORC1/2 inhibitors, with only partial sensitivity to agents that target the PI3K α, β or δ isoforms. Induction of apoptosis only occurred following AKTi treatment in cell lines with PTEN protein loss and high levels of active AKT. In summary, we have demonstrated that T-ALL cell lines show differential sensitivity to inhibition at different nodes in the PI3K/AKT/mTOR pathway and inhibiting AKT or mTOR may have a therapeutic benefit in this disease setting. PMID:26989080

  1. Identification of differential PI3K pathway target dependencies in T-cell acute lymphoblastic leukemia through a large cancer cell panel screen

    PubMed Central

    Lynch, James T.; McEwen, Robert; Crafter, Claire; McDermott, Ultan; Garnett, Mathew J.; Barry, Simon T.; Davies, Barry R.

    2016-01-01

    Selective phosphoinositide 3-kinase (PI3K)/AKT/mTOR inhibitors are currently under evaluation in clinical studies. To identify tumor types that are sensitive to PI3K pathway inhibitors we screened compounds targeting PI3Kα/δ (AZD8835), PI3Kβ/δ (AZD8186), AKT (AZD5363) and mTORC1/2 (AZD2014) against a cancer cell line panel (971 cell lines). There was an enrichment of hematological malignancies that were sensitive to AKT and mTOR inhibition, with the greatest degree of sensitivity observed in T-cell acute lymphoblastic leukemia (T-ALL). We found that all NOTCH mutant T-ALL cell lines were sensitive to AKT and mTORC1/2 inhibitors, with only partial sensitivity to agents that target the PI3K α, β or δ isoforms. Induction of apoptosis only occurred following AKTi treatment in cell lines with PTEN protein loss and high levels of active AKT. In summary, we have demonstrated that T-ALL cell lines show differential sensitivity to inhibition at different nodes in the PI3K/AKT/mTOR pathway and inhibiting AKT or mTOR may have a therapeutic benefit in this disease setting. PMID:26989080

  2. A novel signaling pathway associated with Lyn, PI 3-kinase and Akt supports the proliferation of myeloma cells

    SciTech Connect

    Iqbal, Mohd S.; Tsuyama, Naohiro; Obata, Masanori; Ishikawa, Hideaki

    2010-02-12

    Interleukin-6 (IL-6) is a growth factor for human myeloma cells. We have recently found that in myeloma cells the activation of both signal transducer and activator of transcription (STAT) 3 and extracellular signal-regulated kinase (ERK) 1/2 is not sufficient for the IL-6-induced proliferation, which further requires the activation of the src family kinases, such as Lyn. Here we showed that the Lyn-overexpressed myeloma cell lines had the higher proliferative rate with IL-6 and the enhanced activation of the phosphatidylinositol (PI) 3-kinase and Akt. The IL-6-induced phosphorylation of STAT3 and ERK1/2 was not up-regulated in the Lyn-overexpressed cells, indicating that the Lyn-PI 3-kinase-Akt pathway is independent of these pathways. The PI 3-kinase was co-precipitated with Lyn in the Lyn-overexpressed cells of which proliferation with IL-6 was abrogated by the specific inhibitors for PI 3-kinase or Akt, suggesting that the activation of the PI 3-kinase-Akt pathway associated with Lyn is indeed related to the concomitant augmentation of myeloma cell growth. Furthermore, the decreased expression of p53 and p21{sup Cip1} proteins was observed in the Lyn-overexpressed cells, implicating a possible downstream target of Akt. This study identifies a novel IL-6-mediated signaling pathway that certainly plays a role in the proliferation of myeloma cells and this novel mechanism of MM tumor cell growth associated with Lyn would eventually contribute to the development of MM treatment.

  3. Effects of PI3K inhibitor NVP-BKM120 on overcoming drug resistance and eliminating cancer stem cells in human breast cancer cells

    PubMed Central

    Hu, Y; Guo, R; Wei, J; Zhou, Y; Ji, W; Liu, J; Zhi, X; Zhang, J

    2015-01-01

    The multidrug resistance (MDR) phenotype often accompanies activation of the phosphatidylinositol 3-kinase (PI3K)/AKT pathway, which renders a survival signal to withstand cytotoxic anticancer drugs and enhances cancer stem cell (CSC) characteristics. As a result, PI3K/AKT-blocking approaches have been proposed as antineoplastic strategies, and inhibitors of PI3K/AKT are currently being trailed clinically in breast cancer patients. However, the effects of PI3K inhibitors on MDR breast cancers have not yet been elucidated. In the present study, the tumorigenic properties of three MDR breast cancer cell lines to a selective inhibitor of PI3K, NVP-BKM120 (BKM120), were assessed. We found that BKM120 showed a significant cytotoxic activity on MDR breast cancer cells both in vitro and in vivo. When doxorubicin (DOX) was combined with BKM120, strong synergistic antiproliferative effect was observed. BKM120 activity induced the blockage of PI3K/AKT signaling and NF-κB expression, which in turn led to activate caspase-3/7 and caspase-9 and changed the expression of several apoptosis-related gene expression. Furthermore, BKM120 effectively eliminated CSC subpopulation and reduced sphere formation of these drug-resistant cells. Our findings indicate that BKM120 partially overcomes the MDR phenotype in chemoresistant breast cancer through cell apoptosis induction and CSC abolishing, which appears to be mediated by the inhibition of the PI3K/AKT/NF-κB axis. This offers a strong rationale to explore the therapeutic strategy of using BKM120 alone or in combination for chemotherapy-nonresponsive breast cancer patients. PMID:26673665

  4. Impact of the PI3-kinase/Akt pathway on ITAM and hemITAM receptors: haemostasis, platelet activation and antithrombotic therapy.

    PubMed

    Moroi, Alyssa J; Watson, Steve P

    2015-04-01

    Phosphoinositide 3-kinases (PI3Ks) are a family of lipid kinases that are activated in response to various stimulants, and they regulate many processes including inflammation; the stress response; gene transcription; and cell proliferation, differentiation, and death. Increasing reports have shown that the PI3Ks and their downstream effector Akt are activated by several platelet receptors that regulate platelet activation and haemostasis. Platelets express two immunoreceptor tyrosine based activation motif (ITAM) receptors, collagen receptor glycoprotein VI (GPVI) and Fcγ receptor IIA (FcγRIIA), which are characterized by two YxxL sequences separated by 6-12 amino acids. Activation of an ITAM receptor initiates a reaction cascade via its YxxL sequence in which signaling molecules such as spleen tyrosine kinase (Syk), linker for activation of T cells (LAT) and phospholipase C γ2 (PLCγ2) become activated, leading to platelet activation. Platelets also express another receptor, C-type lectin 2 (CLEC-2), which has a single YxxL sequence, so it is appropriately called a hemITAM receptor. ITAM receptors and the hemITAM receptor share many signaling features. Here we will summarize our current knowledge about how the PI3K/Akt pathway regulates (hem)ITAM receptor-mediated platelet activation and haemostasis and discuss the possible benefits of targeting PI3K/Akt as an antithrombotic therapy.

  5. Proliferation, survival and metabolism: the role of PI3K/AKT/mTOR signalling in pluripotency and cell fate determination.

    PubMed

    Yu, Jason S L; Cui, Wei

    2016-09-01

    Phosphatidylinositide 3 kinases (PI3Ks) and their downstream mediators AKT and mammalian target of rapamycin (mTOR) constitute the core components of the PI3K/AKT/mTOR signalling cascade, regulating cell proliferation, survival and metabolism. Although these functions are well-defined in the context of tumorigenesis, recent studies - in particular those using pluripotent stem cells - have highlighted the importance of this pathway to development and cellular differentiation. Here, we review the recent in vitro and in vivo evidence for the role PI3K/AKT/mTOR signalling plays in the control of pluripotency and differentiation, with a particular focus on the molecular mechanisms underlying these functions. PMID:27578176

  6. Involvement of the PI3K and ERK signaling pathways in largemouth bass virus-induced apoptosis and viral replication.

    PubMed

    Huang, Xiaohong; Wang, Wei; Huang, Youhua; Xu, Liwen; Qin, Qiwei

    2014-12-01

    Increased reports demonstrated that largemouth Bass, Micropterus salmoides in natural and artificial environments were always suffered from an emerging iridovirus disease, largemouth Bass virus (LMBV). However, the underlying mechanism of LMBV pathogenesis remained largely unknown. Here, we investigated the cell signaling events involved in virus induced cell death and viral replication in vitro. We found that LMBV infection in epithelioma papulosum cyprini (EPC) cells induced typical apoptosis, evidenced by the appearance of apoptotic bodies, cytochrome c release, mitochondrial membrane permeabilization (MMP) destruction and reactive oxygen species (ROS) generation. Two initiators of apoptosis, caspase-8 and caspase-9, and the executioner of apoptosis, caspase-3, were all significantly activated with the infection time, suggested that not only mitochondrion-mediated, but also death receptor-mediated apoptosis were involved in LMBV infection. Reporter gene assay showed that the promoter activity of transcription factors including p53, NF-κB, AP-1 and cAMP response element-binding protein (CREB) were decreased during LMBV infection. After treatment with different signaling pathway inhibitors, virus production were significantly suppressed by the inhibition of phosphatidylinositol 3-kinase (PI3K) pathway and extracellular-signal-regulated kinases (ERK) signaling pathway. Furthermore, LMBV infection induced apoptosis was enhanced by PI3K inhibitor LY294002, but decreased by addition of ERK inhibitor UO126. Therefore, we speculated that apoptosis was sophisticatedly regulated by a series of cell signaling events for efficient virus propagation. Taken together, our results provided new insights into the molecular mechanism of ranavirus infection. PMID:25260912

  7. Asiaticoside attenuates diabetes-induced cognition deficits by regulating PI3K/Akt/NF-κB pathway.

    PubMed

    Yin, Zhujun; Yu, Haiyang; Chen, She; Ma, Chunhua; Ma, Xiao; Xu, Lixing; Ma, Zhanqiang; Qu, Rong; Ma, Shiping

    2015-10-01

    Diabetes-associated cognitive dysfunction, referred as "diabetic encephalopathy", has been confirmed in a great deal of literature. Current evidence support that oxidative stress, inflammation, energy metabolism imbalance, and aberrant insulin signaling are associated with cognition deficits induced by diabetes. The present study explore the effect of asiaticoside on the cognition behaviors, synapses, and oxidative stress in diabetic rats. Asiaticoside could markedly ameliorate the performance in the Morris Water Maze (decreased latency time and path length, and increased time spent in the target quadrant), which was correlated with its capabilities of suppressing oxidative stress, restoring Na(+)-K(+)-ATPase activity and protecting hippocampal synapses. In vitro, asiaticoside could up-regulate synaptic proteins expression via modulating Phosphoinositide 3-kinase (PI3K)/Protein Kinase B(AKT)/Nuclear Factor -kappa B (NF-κB)-mediated inflammatory pathway in SH-SY5Y cells incubated with high glucose chronically. In conclusion, asiaticoside had beneficial effects on the prevention and treatment of diabetes-associated cognitive deficits, which was involved in oxidative stress, PI3K/Akt/NF-κB pathway and synaptic function in the development of cognitive decline induced by diabetes.

  8. Involvement of the PI3K and ERK signaling pathways in largemouth bass virus-induced apoptosis and viral replication.

    PubMed

    Huang, Xiaohong; Wang, Wei; Huang, Youhua; Xu, Liwen; Qin, Qiwei

    2014-12-01

    Increased reports demonstrated that largemouth Bass, Micropterus salmoides in natural and artificial environments were always suffered from an emerging iridovirus disease, largemouth Bass virus (LMBV). However, the underlying mechanism of LMBV pathogenesis remained largely unknown. Here, we investigated the cell signaling events involved in virus induced cell death and viral replication in vitro. We found that LMBV infection in epithelioma papulosum cyprini (EPC) cells induced typical apoptosis, evidenced by the appearance of apoptotic bodies, cytochrome c release, mitochondrial membrane permeabilization (MMP) destruction and reactive oxygen species (ROS) generation. Two initiators of apoptosis, caspase-8 and caspase-9, and the executioner of apoptosis, caspase-3, were all significantly activated with the infection time, suggested that not only mitochondrion-mediated, but also death receptor-mediated apoptosis were involved in LMBV infection. Reporter gene assay showed that the promoter activity of transcription factors including p53, NF-κB, AP-1 and cAMP response element-binding protein (CREB) were decreased during LMBV infection. After treatment with different signaling pathway inhibitors, virus production were significantly suppressed by the inhibition of phosphatidylinositol 3-kinase (PI3K) pathway and extracellular-signal-regulated kinases (ERK) signaling pathway. Furthermore, LMBV infection induced apoptosis was enhanced by PI3K inhibitor LY294002, but decreased by addition of ERK inhibitor UO126. Therefore, we speculated that apoptosis was sophisticatedly regulated by a series of cell signaling events for efficient virus propagation. Taken together, our results provided new insights into the molecular mechanism of ranavirus infection.

  9. Fragile Histidine Triad (FHIT) Suppresses Proliferation and Promotes Apoptosis in Cholangiocarcinoma Cells by Blocking PI3K-Akt Pathway

    PubMed Central

    Huang, Qiang; Liu, Zhen; Xie, Fang; Liu, Chenhai; Shao, Feng; Zhu, Cheng-lin; Hu, Sanyuan

    2014-01-01

    Fragile histidine triad (FHIT) is a tumor suppressor protein that regulates cancer cell proliferation and apoptosis. However, its exact mechanism of action is poorly understood. Phosphatidylinositol 3-OH kinase (PI3K)-Akt-survivin is an important signaling pathway that was regulated by FHIT in lung cancer cells. To determine whether FHIT can regulate this pathway in cholangiocarcinoma QBC939 cells, we constructed an FHIT expression plasmid and used it to transfect QBC939 cells. Protein and mRNA expression were measured by western blotting and qRT-PCR, respectively. The viability and apoptosis of QBC939 cells were then assessed using MTT assays and flow cytometry. Our results revealed that the expression of survivin and Bcl-2 was downregulated, and caspase 3 was upregulated, in cells overexpressing FHIT. In addition, FHIT suppressed the phosphorylation of Akt. The changes in cell proliferation and apoptosis were obvious in cells overexpressing FHIT which parallels that of treatment with LY294002, a potent inhibitor of phosphoinositide 3-kinases. Treatment with LY294002 further decreased the expression of survivin and Bcl-2 and increased caspase-3 levels. These results suggest that FHIT can block the PI3K-Akt-survivin pathway by suppressing the phosphorylation of Akt and the expression of survivin and Bcl-2 and upregulating caspase 3. PMID:24757411

  10. PI3K regulates endocytosis after insulin secretion by mediating signaling crosstalk between Arf6 and Rab27a.

    PubMed

    Yamaoka, Mami; Ando, Tomomi; Terabayashi, Takeshi; Okamoto, Mitsuhiro; Takei, Masahiro; Nishioka, Tomoki; Kaibuchi, Kozo; Matsunaga, Kohichi; Ishizaki, Ray; Izumi, Tetsuro; Niki, Ichiro; Ishizaki, Toshimasa; Kimura, Toshihide

    2016-02-01

    In secretory cells, endocytosis is coupled to exocytosis to enable proper secretion. Although endocytosis is crucial to maintain cellular homeostasis before and after secretion, knowledge about secretagogue-induced endocytosis in secretory cells is still limited. Here, we searched for proteins that interacted with the Rab27a GTPase-activating protein (GAP) EPI64 (also known as TBC1D10A) and identified the Arf6 guanine-nucleotide-exchange factor (GEF) ARNO (also known as CYTH2) in pancreatic β-cells. We found that the insulin secretagogue glucose promotes phosphatidylinositol (3,4,5)-trisphosphate (PIP3) generation through phosphoinositide 3-kinase (PI3K), thereby recruiting ARNO to the intracellular side of the plasma membrane. Peripheral ARNO promotes clathrin assembly through its GEF activity for Arf6 and regulates the early stage of endocytosis. We also found that peripheral ARNO recruits EPI64 to the same area and that the interaction requires glucose-induced endocytosis in pancreatic β-cells. Given that GTP- and GDP-bound Rab27a regulate exocytosis and the late stage of endocytosis, our results indicate that the glucose-induced activation of PI3K plays a pivotal role in exocytosis-endocytosis coupling, and that ARNO and EPI64 regulate endocytosis at distinct stages.

  11. Dimethyl Cardamonin Exhibits Anti-inflammatory Effects via Interfering with the PI3K-PDK1-PKCα Signaling Pathway

    PubMed Central

    Yu, Wan-Guo; He, Hao; Yao, Jing-Yun; Zhu, Yi-Xiang; Lu, Yan-Hua

    2015-01-01

    Consumption of herbal tea [flower buds of Cleistocalyx operculatus (Roxb.) Merr. et Perry (Myrtaceae)] is associated with health beneficial effects against multiple diseases including diabetes, asthma, and inflammatory bowel disease. Emerging evidences have reported that High mobility group box 1 (HMGB1) is considered as a key “late” proinflammatory factor by its unique secretion pattern in aforementioned diseases. Dimethyl cardamonin (2′,4′-dihydroxy-6′-methoxy-3′,5′-dimethylchalcone, DMC) is a major ingredient of C. operculatus flower buds. In this study, the anti-inflammatory effects of DMC and its underlying molecular mechanisms were investigated on lipopolysaccharide (LPS)-induced macrophages. DMC notably suppressed the mRNA expressions of TNF-α, IL-1β, IL-6, and HMGB1, and also markedly decreased their productions in a time- and dose-dependent manner. Intriguingly, DMC could notably reduce LPS-stimulated HMGB1 secretion and its nucleo-cytoplasmic translocation. Furthermore, DMC dose-dependently inhibited the activation of phosphatidylinositol 3-kinase (PI3K), phosphoinositide-dependent kinase 1 (PDK1), and protein kinase C alpha (PKCα). All these data demonstrated that DMC had anti-inflammatory effects through reducing both early (TNF-α, IL-1β, and IL-6) and late (HMGB1) cytokines expressions via interfering with the PI3K-PDK1-PKCα signaling pathway. PMID:26535080

  12. Herbacetin induces apoptosis in HepG2 cells: Involvements of ROS and PI3K/Akt pathway.

    PubMed

    Qiao, Yan; Xiang, Qisen; Yuan, Li; Xu, Li; Liu, Zhigang; Liu, Xuebo

    2013-01-01

    Herbacetin (HER) is a natural flavonoid compound that can be extracted from Ramose Scouring Rush Herb, and its biological and pharmacological activities lack of corresponding attention. In this study, the apoptotic effect of HER against the human hepatoma cell line (HepG2) was investigated. The results showed that HepG2 cells apoptosis occurred in a dose-dependent manner within 48h incubated with HER, which was confirmed by DNA fragmentation, nuclear shrinkage, and poly (ADP-ribose) polymerase (PARP) cleavage. HER at 25-100μM induced a mitochondria-dependent apoptotic pathway associated with Bcl-2/Bax ratio decrease, mitochondrial membrane potential (ΔΨ) collapse, cytochrome c release, and caspase-3 activation. Increasing expression of peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α) was also observed in HER-treated cells. Furthermore, the addition of a ROS inhibitor (N-Acetyl-l-cysteine, NAC) significantly attenuated the apoptosis induced by HER and also blocked the expression of PGC-1α protein. Additionally, HER effectively inhibited the phosphorylation of Akt and the phosphatidylinositol-3 kinase (PI3K) inhibitor LY294002 increased the inhibition effect of HER on Akt phosphorylation. These findings provide evidences that HER induces HepG2 apoptosis in a ROS-mediated mitochondria-dependent manner that correlate with the inactivation of the PI3K/Akt pathway. PMID:23063593

  13. Thymoquinone attenuates liver fibrosis via PI3K and TLR4 signaling pathways in activated hepatic stellate cells.

    PubMed

    Bai, Ting; Lian, Li-Hua; Wu, Yan-Ling; Wan, Ying; Nan, Ji-Xing

    2013-02-01

    Thymoquinone (TQ) is the major active compound derived from the medicinal Nigella sativa. In the present study, we investigated the anti-fibrotic mechanism of TQ in lipopolysaccharide (LPS)-activated rat hepatic stellate cells line, T-HSC/Cl-6. T-HSC/Cl-6 cells were treated with TQ (3.125, 6.25 and 12.5μM) prior to LPS (1μg/ml). Our data demonstrated that TQ effectively decreased activated T-HSC/Cl-6 cell viability. TQ significantly attenuated the expression of CD14 and Toll-like receptor 4 (TLR4). TQ also significantly inhibited phosphatidylinositol 3-kinase (PI3K) and serine/threonine kinase-protein kinase B (Akt) phosphorylation. The expression of α-SMA and collagen-I were significantly decreased by TQ. Furthermore, TQ decreased X linked inhibitor of apoptosis (XIAP) and cellular FLIP (c-FLIPL) expression, which are related with the regulation of apoptosis. Furthermore, TQ significantly increased the survival against LPS challenge in d-galactosamine (d-GlaN)-sensitized mice, and decreased the levels of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST), which were in line with in vitro results. Our data demonstrated that TQ attenuates liver fibrosis partially via blocking TLR4 expression and PI3K phosphorylation on the activated HSCs. Therefore, TQ may be a potential candidate for the therapy of hepatic fibrosis.

  14. PI3K-AKT signaling is a downstream effector of retinoid prevention of murine basal cell carcinogenesis.

    PubMed

    So, Po-Lin; Wang, Grace Y; Wang, Kevin; Chuang, Mindy; Chiueh, Venice Calinisan; Kenny, Paraic A; Epstein, Ervin H

    2014-04-01

    Basal cell carcinoma (BCC) is the most common human cancer. We have demonstrated previously that topical application of the retinoid prodrug tazarotene profoundly inhibits murine BCC carcinogenesis via retinoic acid receptor γ-mediated regulation of tumor cell transcription. Because topical retinoids can cause adverse cutaneous effects and because tumors can develop resistance to retinoids, we have investigated mechanisms downstream of tazarotene's antitumor effect in this model. Specifically we have used (i) global expression profiling to identify and (ii) functional cell-based assays to validate the phosphoinositide 3-kinase (PI3K)/AKT/mTOR pathway as a downstream target pathway of tazarotene's action. Crucially, we have demonstrated that pharmacologic inhibition of this downstream pathway profoundly reduces murine BCC cell proliferation and tumorigenesis both in vitro and in vivo. These data identify PI3K/AKT/mTOR signaling as a highly attractive target for BCC chemoprevention and indicate more generally that this pathway may be, in some contexts, an important mediator of retinoid anticancer effects.

  15. Allosteric modulation of Ras and the PI3K/AKT/mTOR pathway: emerging therapeutic opportunities

    PubMed Central

    Hubbard, Paul A.; Moody, Colleen L.; Murali, Ramachandran

    2014-01-01

    GTPases and kinases are two predominant signaling modules that regulate cell fate. Dysregulation of Ras, a GTPase, and the three eponymous kinases that form key nodes of the associated phosphatidylinositol 4,5-bisphosphate 3-kinase (PI3K)/AKT/mTOR pathway have been implicated in many cancers, including pancreatic cancer, a disease noted for its current lack of effective therapeutics. The K-Ras isoform of Ras is mutated in over 90% of pancreatic ductal adenocarcinomas (PDAC) and there is growing evidence linking aberrant PI3K/AKT/mTOR pathway activity to PDAC. Although these observations suggest that targeting one of these nodes might lead to more effective treatment options for patients with pancreatic and other cancers, the complex regulatory mechanisms and the number of sequence-conserved isoforms of these proteins have been viewed as significant barriers in drug development. Emerging insights into the allosteric regulatory mechanisms of these proteins suggest novel opportunities for development of selective allosteric inhibitors with fragment-based drug discovery (FBDD) helping make significant inroads. The fact that allosteric inhibitors of Ras and AKT are currently in pre-clinical development lends support to this approach. In this article, we will focus on the recent advances and merits of developing allosteric drugs targeting these two inter-related signaling pathways. PMID:25566081

  16. Allosteric modulation of Ras and the PI3K/AKT/mTOR pathway: emerging therapeutic opportunities.

    PubMed

    Hubbard, Paul A; Moody, Colleen L; Murali, Ramachandran

    2014-01-01

    GTPases and kinases are two predominant signaling modules that regulate cell fate. Dysregulation of Ras, a GTPase, and the three eponymous kinases that form key nodes of the associated phosphatidylinositol 4,5-bisphosphate 3-kinase (PI3K)/AKT/mTOR pathway have been implicated in many cancers, including pancreatic cancer, a disease noted for its current lack of effective therapeutics. The K-Ras isoform of Ras is mutated in over 90% of pancreatic ductal adenocarcinomas (PDAC) and there is growing evidence linking aberrant PI3K/AKT/mTOR pathway activity to PDAC. Although these observations suggest that targeting one of these nodes might lead to more effective treatment options for patients with pancreatic and other cancers, the complex regulatory mechanisms and the number of sequence-conserved isoforms of these proteins have been viewed as significant barriers in drug development. Emerging insights into the allosteric regulatory mechanisms of these proteins suggest novel opportunities for development of selective allosteric inhibitors with fragment-based drug discovery (FBDD) helping make significant inroads. The fact that allosteric inhibitors of Ras and AKT are currently in pre-clinical development lends support to this approach. In this article, we will focus on the recent advances and merits of developing allosteric drugs targeting these two inter-related signaling pathways. PMID:25566081

  17. Zinc promotes proliferation and activation of myogenic cells via the PI3K/Akt and ERK signaling cascade

    SciTech Connect

    Ohashi, Kazuya; Nagata, Yosuke; Wada, Eiji; Zammit, Peter S.; Shiozuka, Masataka; Matsuda, Ryoichi

    2015-05-01

    Skeletal muscle stem cells named muscle satellite cells are normally quiescent but are activated in response to various stimuli, such as injury and overload. Activated satellite cells enter the cell cycle and proliferate to produce a large number of myogenic progenitor cells, and these cells then differentiate and fuse to form myofibers. Zinc is one of the essential elements in the human body, and has multiple roles, including cell growth and DNA synthesis. However, the role of zinc in myogenic cells is not well understood, and is the focus of this study. We first examined the effects of zinc on differentiation of murine C2C12 myoblasts and found that zinc promoted proliferation, with an increased number of cells incorporating EdU, but inhibited differentiation with reduced myogenin expression and myotube formation. Furthermore, we used the C2C12 reserve cell model of myogenic quiescence to investigate the role of zinc on activation of myogenic cells. The number of reserve cells incorporating BrdU was increased by zinc in a dose dependent manner, with the number dramatically further increased using a combination of zinc and insulin. Akt and extracellular signal-regulated kinase (ERK) are downstream of insulin signaling, and both were phosphorylated after zinc treatment. The zinc/insulin combination-induced activation involved the phosphoinositide 3-kinase (PI3K)/Akt and ERK cascade. We conclude that zinc promotes activation and proliferation of myogenic cells, and this activation requires phosphorylation of PI3K/Akt and ERK as part of the signaling cascade. - Highlights: • Zinc has roles for promoting proliferation and inhibition differentiation of C2C12. • Zinc promotes activation of reserve cells. • Insulin and zinc synergize activation of reserve cells. • PI3K/Akt and ERK cascade affect zinc/insulin-mediated activation of reserve cells.

  18. Treadmill exercise reduces spinal cord injury-induced apoptosis by activating the PI3K/Akt pathway in rats.

    PubMed

    Jung, Sun-Young; Kim, Dae-Young; Yune, Tae Young; Shin, Dong-Hoon; Baek, Sang-Bin; Kim, Chang-Ju

    2014-03-01

    Apoptosis occurring secondary to spinal cord injury (SCI) causes further neural damage and functional loss. In this study, a rat model was used to investigate the effect of treadmill exercise on SCI-induced apoptosis and expression of neurotrophic factors. To produce SCI, a contusion injury (10 g × 25 mm) was applied subsequent to laminectomy at the T9-T10 level. Following SCI, treadmill exercise was performed for six weeks. Hindlimb motor function was evaluated with a grid-walking test. The expression of neurotrophic factors and the level of apoptosis at the site of SCI were determined by western blotting. SCI reduced hindlimb motor function and suppressed expression of neurotrophin (NT)-3 and insulin-like growth factor (IGF)-1. Expression of phosphatidylinositol 3-kinase (PI3K), the ratio of phosphorylated Akt to Akt (pAkt/Akt) and the ratio of B-cell lymphoma 2 (Bcl-2) to Bax (Bcl-2/Bax) were decreased, and cleaved caspase-3 expression was increased by SCI. Treadmill exercise enhanced hindlimb motor function and increased expression of nerve growth factor (NGF), NT-3 and IGF-1 in the SCI rats. Treadmill exercise increased PI3K expression, the pAkt/Akt and the Bcl-2/Bax ratios, and suppressed cleaved caspase-3 expression in the injured spinal cord. This study demonstrated that treadmill exercise promotes the recovery of motor function by suppressing apoptosis in the injured spinal cord. The beneficial effect of exercise may be attributed to the increase in expression of neurotrophic factors via activation of the PI3K/Akt pathway.

  19. Vitamin E succinate induces apoptosis via the PI3K/AKT signaling pathways in EC109 esophageal cancer cells

    PubMed Central

    Yang, Peng; Zhao, Jiaying; Hou, Liying; Yang, Lei; Wu, Kun; Zhang, Linyou

    2016-01-01

    Esophageal cancer is the fourth most common gastrointestinal cancer, it generally has a poor prognosis and novel strategies are required for prevention and treatment. Vitamin E succinate (VES) is a potential chemical agent for cancer prevention and therapy as it exerts anti-tumor effects in a variety of cancers. However, the role of VES in tumorigenesis and progression of cancer remains to be elucidated. The present study aimed to determine the effects of VES in regulating the survival and apoptosis of human esophageal cancer cells. EC109 human esophageal cancer cells were used to investigate the anti-proliferative effects of VES. The MTT and Annexin V-fluorescein isothiocyanate/propidium iodide assays demonstrated that VES inhibited cell proliferation and induced apoptosis in esophageal cancer cells. Furthermore, VES downregulated constitutively active basal levels of phosphorylated (p)-serine-threonine kinase AKT (AKT) and p-mammalian target of rapamycin (mTOR), and decreased the phosphorylation of AKT substrates Bcl-2-associated death receptor and caspase-9, in addition to mTOR effectors, ribosomal protein S6 kinase β1 and eIF4E-binding protein 1. Phosphoinositide-3-kinase (PI3K) inhibitor, LY294002 suppressed p-AKT and p-mTOR, indicating PI3K is a common upstream mediator. The apoptosis induced by VES was increased by inhibition of AKT or mTOR with their respective inhibitor in esophageal cancer cells. The results of the present study suggested that VES targeted the PI3K/AKT signaling pathways and induced apoptosis in esophageal cancer cells. Furthermore, the current study suggests that VES may be useful in a combinational therapeutic strategy employing an mTOR inhibitor. PMID:27357907

  20. Targeting EMP3 suppresses proliferation and invasion of hepatocellular carcinoma cells through inactivation of PI3K/Akt pathway.

    PubMed

    Hsieh, Yi-Hsien; Hsieh, Shu-Ching; Lee, Chien-Hsing; Yang, Shun-Fa; Cheng, Chun-Wen; Tang, Meng-Ju; Lin, Chia-Liang; Lin, Chu-Liang; Chou, Ruey-Hwang

    2015-10-27

    Epithelial membrane protein-3 (EMP3), a typical member of the epithelial membrane protein (EMP) family, is epigenetically silenced in some cancer types, and has been proposed to be a tumor suppressor gene. However, its effects on tumor suppression are controversial and its roles in development and malignancy of hepatocellular carcinoma (HCC) remain unclear. In the present study, we found that EMP3 was highly expressed in the tumorous tissues comparing to the matched normal tissues, and negatively correlated with differentiated degree of HCC patients. Knockdown of EMP3 significantly reduced cell proliferation, arrested cell cycle at G1 phase, and inhibited the motility and invasiveness in accordance with the decreased expression and activity of urokinase plasminogen activator (uPA) and matrix metalloproteinase 9 (MMP-9) in HCC cells. The in vivo tumor growth of HCC was effectively suppressed by knockdown of EMP3 in a xenograft mouse model. The EMP3 knockdown-reduced cell proliferation and invasion were attenuated by inhibition of phosphatidylinositol 3-kinase (PI3K) or knockdown of Akt, and rescued by overexpression of Akt in HCC cells. Clinical positive correlations of EMP3 with p85 regulatory subunit of PI3K, p-Akt, uPA, as well as MMP-9 were observed in the tissue sections from HCC patients. Here, we elucidated the tumor progressive effects of EMP3 through PI3K/Akt pathway and uPA/MMP-9 cascade in HCC cells. The findings provided a new insight into EMP3, which might be a potential molecular target for diagnosis and treatment of HCC. PMID:26472188

  1. Inhibition of PI3K Signalling Selectively Affects Medulloblastoma Cancer Stem Cells.

    PubMed

    Frasson, Chiara; Rampazzo, Elena; Accordi, Benedetta; Beggio, Giacomo; Pistollato, Francesca; Basso, Giuseppe; Persano, Luca

    2015-01-01

    Medulloblastoma is the most common malignant brain tumor of childhood. Although survival has slowly increased in the past years, the prognosis of these patients remains unfavourable. In this context, it has been recently shown that the intracellular signaling pathways activated during embryonic cerebellar development are deregulated in MDB. One of the most important is PI3K/AKT/mTOR, implicated in cell proliferation, survival, growth, and protein synthesis. Moreover, a fraction of MDB cells has been shown to posses stemlike features, to express typical neuronal precursor markers (Nestin and CD133), and to be maintained by the hypoxic cerebellar microenvironment. This subpopulation of MDB cells is considered to be responsible for treatment resistance and recurrence. In this study, we evaluated the effects of PI3K/AKT pathway inhibition on primary cultures of MDB and particularly on the cancer stem cell (CSC) population (CD133(+)). PI3K inhibition was able to counteract MDB cell growth and to promote differentiation of stemlike MDB cells. Moreover, PI3K/AKT pathway suppression induced dramatic cell death through activation of the mitochondrial proapoptotic cascade. Finally, analysis on the stem cells fraction revealed that the MDB CSC population is more sensitive to PI3K targeting compared to the whole cancerous population and its nonstem cell counterpart.

  2. Puerarin activates endothelial nitric oxide synthase through estrogen receptor-dependent PI3-kinase and calcium-dependent AMP-activated protein kinase

    SciTech Connect

    Hwang, Yong Pil; Kim, Hyung Gyun; Hien, Tran Thi; Jeong, Myung Ho; Jeong, Tae Cheon; Jeong, Hye Gwang

    2011-11-15

    The cardioprotective properties of puerarin, a natural product, have been attributed to the endothelial nitric oxide synthase (eNOS)-mediated production of nitric oxide (NO) in EA.hy926 endothelial cells. However, the mechanism by which puerarin activates eNOS remains unclear. In this study, we sought to identify the intracellular pathways underlying eNOS activation by puerarin. Puerarin induced the activating phosphorylation of eNOS on Ser1177 and the production of NO in EA.hy926 cells. Puerarin-induced eNOS phosphorylation required estrogen receptor (ER)-mediated phosphatidylinositol 3-kinase (PI3K)/Akt signaling and was reversed by AMP-activated protein kinase (AMPK) and calcium/calmodulin-dependent kinase II (CaMKII) inhibition. Importantly, puerarin inhibited the adhesion of tumor necrosis factor (TNF)-{alpha}-stimulated monocytes to endothelial cells and suppressed the TNF-{alpha} induced expression of intercellular cell adhesion molecule-1. Puerarin also inhibited the TNF-{alpha}-induced nuclear factor-{kappa}B activation, which was attenuated by pretreatment with N{sup G}-nitro-L-arginine methyl ester, a NOS inhibitor. These results indicate that puerarin stimulates eNOS phosphorylation and NO production via activation of an estrogen receptor-mediated PI3K/Akt- and CaMKII/AMPK-dependent pathway. Puerarin may be useful for the treatment or prevention of endothelial dysfunction associated with diabetes and cardiovascular disease. -- Highlights: Black-Right-Pointing-Pointer Puerarin induced the phosphorylation of eNOS and the production of NO. Black-Right-Pointing-Pointer Puerarin activated eNOS through ER-dependent PI3-kinase and Ca{sup 2+}-dependent AMPK. Black-Right-Pointing-Pointer Puerarin-induced NO was involved in the inhibition of NF-kB activation. Black-Right-Pointing-Pointer Puerarin may help for prevention of vascular dysfunction and diabetes.

  3. Class IA PI3Kinase Regulatory Subunit, p85α, Mediates Mast Cell Development through Regulation of Growth and Survival Related Genes

    PubMed Central

    Krishnan, Subha; Mali, Raghuveer Singh; Koehler, Karl R.; Vemula, Sasidhar; Chatterjee, Anindya; Ghosh, Joydeep; Ramdas, Baskar; Ma, Peilin; Hashino, Eri; Kapur, Reuben

    2012-01-01

    Stem cell factor (SCF) mediated KIT receptor activation plays a pivotal role in mast cell growth, maturation and survival. However, the signaling events downstream from KIT are poorly understood. Mast cells express multiple regulatory subunits of class 1A PI3Kinase (PI3K) including p85α, p85β, p50α, and p55α. While it is known that PI3K plays an essential role in mast cells; the precise mechanism by which these regulatory subunits impact specific mast cell functions including growth, survival and cycling are not known. We show that loss of p85α impairs the growth, survival and cycling of mast cell progenitors (MCp). To delineate the molecular mechanism (s) by which p85α regulates mast cell growth, survival and cycling, we performed microarray analyses to compare the gene expression profile of MCps derived from WT and p85α-deficient mice in response to SCF stimulation. We identified 151 unique genes exhibiting altered expression in p85α-deficient cells in response to SCF stimulation compared to WT cells. Functional categorization based on DAVID bioinformatics tool and Ingenuity Pathway Analysis (IPA) software relates the altered genes due to lack of p85α to transcription, cell cycle, cell survival, cell adhesion, cell differentiation, and signal transduction. Our results suggest that p85α is involved in mast cell development through regulation of expression of growth, survival and cell cycle related genes. PMID:22238586

  4. PTEN and PI3K/AKT in non-small-cell lung cancer.

    PubMed

    Pérez-Ramírez, Cristina; Cañadas-Garre, Marisa; Molina, Miguel Ángel; Faus-Dáder, María José; Calleja-Hernández, Miguel Ángel

    2015-11-01

    Non-small-cell lung cancer (NSCLC) is the leading cause of cancer deaths worldwide. In the last years, the identification of activating EGFR mutations, conferring increased sensitivity and disease response to tyrosine kinase inhibitors, has changed the prospect of NSCLC patients. The PTEN/PI3K/AKT pathway regulates multiple cellular functions, including cell growth, differentiation, proliferation, survival, motility, invasion and intracellular trafficking. Alterations in this pathway, mainly PTEN inactivation, have been associated with resistance to EGFR-tyrosine kinase inhibitor therapy and lower survival in NSCLC patients. In this review, we will briefly discuss the main PTEN/PI3K/AKT pathway alterations found in NSCLC, as well as the cell processes regulated by PTEN/PI3K/AKT leading to tumorigenesis.

  5. Quantitative phosphoproteomic analysis of the PI3K-regulated signaling network.

    PubMed

    Gnad, Florian; Wallin, Jeffrey; Edgar, Kyle; Doll, Sophia; Arnott, David; Robillard, Liliane; Kirkpatrick, Donald S; Stokes, Matthew P; Vijapurkar, Ulka; Hatzivassiliou, Georgia; Friedman, Lori S; Belvin, Marcia

    2016-07-01

    The PI3K pathway is commonly activated in cancer. Only a few studies have attempted to explore the spectrum of phosphorylation signaling downstream of the PI3K cascade. Such insight, however, is imperative to understand the mechanisms responsible for oncogenic phenotypes. By applying MS-based phosphoproteomics, we mapped 2509 phosphorylation sites on 1096 proteins, and quantified their responses to activation or inhibition of PIK3CA using isogenic knock-in derivatives and a series of targeted inhibitors. We uncovered phosphorylation changes in a wide variety of proteins involved in cell growth and proliferation, many of which have not been previously associated with PI3K signaling. A significant update of the posttranslational modification database PHOSIDA (http://www.phosida.com) allows efficient use of the data. All MS data have been deposited in the ProteomeXchange with identifier PXD003899 (http://proteomecentral.proteomexchange.org/dataset/PXD003899). PMID:27282143

  6. PI3K pathway inhibitors: potential prospects as adjuncts to vaccine immunotherapy for glioblastoma.

    PubMed

    Oh, Taemin; Ivan, Michael E; Sun, Matthew Z; Safaee, Michael; Fakurnejad, Shayan; Clark, Aaron J; Sayegh, Eli T; Bloch, Orin; Parsa, Andrew T

    2014-01-01

    Constitutive activation of the PI3K pathway has been implicated in glioblastoma (GBM) pathogenesis. Pharmacologic inhibition can both inhibit tumor survival and downregulate expression of programmed death ligand-1, a protein highly expressed on glioma cells that strongly contributes to cancer immunosuppression. In that manner, PI3K pathway inhibitors can help optimize GBM vaccine immunotherapy. In this review, we describe and assess the potential integration of various classes of PI3K pathway inhibitors into GBM immunotherapy. While early-generation inhibitors have a wide range of immunosuppressive effects that could negate their antitumor potency, further work should better characterize how contemporary inhibitors affect the immune response. This will help determine if these inhibitors are truly a therapeutic avenue with a strong future in GBM immunotherapy.

  7. PI3K inhibitors prime neuroblastoma cells for chemotherapy by shifting the balance towards pro-apoptotic Bcl-2 proteins and enhanced mitochondrial apoptosis.

    PubMed

    Bender, A; Opel, D; Naumann, I; Kappler, R; Friedman, L; von Schweinitz, D; Debatin, K-M; Fulda, S

    2011-01-27

    We recently identified activation of phosphatidylinositol 3'-kinase (PI3K)/Akt as a novel predictor of poor outcome in neuroblastoma. Here, we investigated the effect of small-molecule PI3K inhibitors on chemosensitivity. We provide first evidence that PI3K inhibitors, for example PI103, synergize with various chemotherapeutics (Doxorubicin, Etoposide, Topotecan, Cisplatin, Vincristine and Taxol) to trigger apoptosis in neuroblastoma cells (combination index: high synergy). Mechanistic studies reveal that PI103 cooperates with Doxorubicin to reduce Mcl-1 expression and Bim(EL) phosphorylation and to upregulate Noxa and Bim(EL) levels. This shifted ratio of pro- and antiapoptotic Bcl-2 proteins results in increased Bax/Bak conformational change, loss of mitochondrial membrane potential, cytochrome c release, caspase activation and caspase-dependent apoptosis. Although Mcl-1 knockdown enhances Doxorubicin- and PI103-induced apoptosis, silencing of Noxa, Bax/Bak or p53 reduces apoptosis, underscoring the functional relevance of the Doxorubicin- and PI103-mediated modulation of these proteins for chemosensitization. Bcl-2 overexpression inhibits Bax activation, mitochondrial perturbations, cleavage of caspases and Bid, and apoptosis, confirming the central role of the mitochondrial pathway for chemosensitization. Interestingly, the broad-range caspase inhibitor zVAD.fmk does not interfere with Bax activation or mitochondrial outer membrane permeabilization, whereas it blocks caspase activation and apoptosis, thus placing mitochondrial events upstream of caspase activation. Importantly, PI103 and Doxorubicin cooperate to induce apoptosis and to suppress tumor growth in patients' derived primary neuroblastoma cells and in an in vivo neuroblastoma model, underlining the clinical relevance of the results. Thus, targeting PI3K presents a novel and promising strategy to sensitize neuroblastoma cells for chemotherapy-induced apoptosis, which has important implications for the

  8. Cell type-specific dependency on the PI3K/Akt signaling pathway for the endogenous Epo and VEGF induction by baicalein in neurons versus astrocytes.

    PubMed

    Sun, Yu-Yo; Lin, Shang-Hsuan; Lin, Hung-Cheng; Hung, Chia-Chi; Wang, Chen-Yu; Lin, Yen-Chu; Hung, Kuo-Sheng; Lien, Cheng-Chang; Kuan, Chia-Yi; Lee, Yi-Hsuan

    2013-01-01

    The neuroprotective effect of baicalein is generally attributed to inhibition of 12/15-lipoxygenase (12/15-LOX) and suppression of oxidative stress, but recent studies showed that baicalein also activates hypoxia-inducible factor-α (HIF1α) through inhibition of prolyl hydrolase 2 (PHD2) and activation of the phosphatidylinositide-3 kinase (PI3K)/Akt signaling pathway. Yet, the significance and regulation of prosurvival cytokines erythropoietin (Epo) and vascular endothelial growth factor (VEGF), two transcriptional targets of HIF1α, in baicalein-mediated neuroprotection in neurons and astrocytes remains unknown. Here we investigated the causal relationship between the PI3K/Akt signaling pathway and Epo/VEGF expression in baicalein-mediated neuroprotection in primary rat cortical neurons and astrocytes. Our results show that baicalein induced Epo and VEGF expression in a HIF1α- and PI3K/Akt-dependent manner in neurons. Baicalein also protected neurons against excitotoxicity in a PI3K- and Epo/VEGF-dependent manner without affecting neuronal excitability. In contrast, at least a 10-fold higher concentration of baicalein was needed to induce Epo/VEGF production and PI3K/Akt activity in astrocytes for protection of neurons. Moreover, only baicalein-induced astrocytic VEGF, but not Epo expression requires HIF1α, while PI3K/Akt signaling had little role in baicalein-induced astrocytic Epo/VEGF expression. These results suggest distinct mechanisms of baicalein-mediated Epo/VEGF production in neurons and astrocytes for neuroprotection, and provide new insights into the mechanisms and potential of baicalein in treating brain injury in vivo. PMID:23904909

  9. γ-Enolase C-terminal peptide promotes cell survival and neurite outgrowth by activation of the PI3K/Akt and MAPK/ERK signalling pathways.

    PubMed

    Hafner, Anja; Obermajer, Nataša; Kos, Janko

    2012-04-15

    γ-Enolase, a glycolytic enzyme, is expressed specifically in neurons. It exerts neurotrophic activity and has been suggested to regulate growth, differentiation, survival and regeneration of neurons. In the present study, we investigated the involvement of γ-enolase in PI3K (phosphoinositide 3-kinase)/Akt and MAPK (mitogen-activated protein kinase)/ERK (extracellular-signal-regulated kinase) signalling, the two pathways triggered predominantly by neurotrophic factors. Whereas the PI3K/Akt pathway, rather than the MAPK/ERK pathway, is involved in γ-enolase-enhanced cell survival, γ-enolase-stimulated neurite outgrowth requires both pathways, i.e. the activation of both PI3K and ERK1/2, leading to subsequent expression of the growth-cone-specific protein GAP-43 (growth-associated protein of 43 kDa). MEK (MAPK/ERK kinase) and PI3K inhibition blocked or attenuated the neurite outgrowth associated with dynamic remodelling of the actin-based cytoskeleton. We show that γ-enolase-mediated PI3K activation regulates RhoA kinase, a key regulator of actin cytoskeleton organization. Moreover, the inhibition of RhoA downstream effector ROCK (Rho-associated kinase) results in enhanced γ-enolase-induced neurite outgrowth, accompanied by actin polymerization and its redistribution to growth cones. Our results show that γ-enolase controls neuronal survival, differentiation and neurite regeneration by activating the PI3K/Akt and MAPK/ERK signalling pathways, resulting in downstream regulation of the molecular and cellular processes of cytoskeleton reorganization and cell remodelling, activation of transcriptional factors and regulation of the cell cycle.

  10. Crosstalk Between MAPK/ERK and PI3K/AKT Signal Pathways During Brain Ischemia/Reperfusion

    PubMed Central

    Zhou, Jing; Du, Ting; Li, Baoman; Rong, Yan; Verkhratsky, Alexei

    2015-01-01

    The epidermal growth factor receptor (EGFR) is linked to the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) and Raf/mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK1/2) signaling pathways. During brain ischemia/reperfusion, EGFR could be transactivated, which stimulates these intracellular signaling cascades that either protect cells or potentiate cell injury. In the present study, we investigated the activation of EGFR, PI3K/AKT, and Raf/MAPK/ERK1/2 during ischemia or reperfusion of the brain using the middle cerebral artery occlusion model. We found that EGFR was phosphorylated and transactivated during both ischemia and reperfusion periods. During ischemia, the activity of PI3K/AKT pathway was significantly increased, as judged from the strong phosphorylation of AKT; this activation was suppressed by the inhibitors of EGFR and Zn-dependent metalloproteinase. Ischemia, however, did not induce ERK1/2 phosphorylation, which was dependent on reperfusion. Coimmunoprecipitation of Son of sevenless 1 (SOS1) with EGFR showed increased association between the receptor and SOS1 in ischemia, indicating the inhibitory node downstream of SOS1. The inhibitory phosphorylation site of Raf-1 at Ser259, but not its stimulatory phosphorylation site at Ser338, was phosphorylated during ischemia. Furthermore, ischemia prompted the interaction between Raf-1 and AKT, while both the inhibitors of PI3K and AKT not only abolished AKT phosphorylation but also restored ERK1/2 phosphorylation. All these findings suggest that Raf/MAPK/ERK1/2 signal pathway is inhibited by AKT via direct phosphorylation and inhibition at Raf-1 node during ischemia. During reperfusion, we observed a significant increase of ERK1/2 phosphorylation but no change in AKT phosphorylation. Inhibitors of reactive oxygen species and phosphatase and tensin homolog restored AKT phosphorylation but abolished ERK1/2 phosphorylation, suggesting that the reactive oxygen species

  11. Sphingosine-1-phosphate receptor 2 mediates endothelial cells dysfunction by PI3K-Akt pathway under high glucose condition.

    PubMed

    Liu, Weihua; Liu, Bin; Liu, Shaojun; Zhang, Jingzhi; Lin, Shuangfeng

    2016-04-01

    Endothelial dysfunction is believed the early stage of development of diabetic cardiovascular complications. Sphingosine-1-phosphate (S1P) regulates various biological activities by binding to sphingosine-1-phosphate receptors (S1PRs) including S1PR1-S1PR5. In the present study, the role of S1P receptors in S1P-induced human coronary artery endothelial cells (HCAECs) dysfunction under high glucose condition was investigated and the underlying mechanism was explored. S1PR1-S1PR5 mRNA levels were detected by quantitative Real-time PCR. NO level and polymorphonuclear neutrophils (PMN)-endothelial cells adhesion were measured by nitrate reductase and myeloperoxidase colorimetric method, respectively. Protein levels of endothelial nitric oxide synthase (eNOS), vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1(ICAM-1), phosphatidylinositol 3-kinase (PI3K) and Akt were measured by Western blot analysis. S1PR2 were found the predominant S1P receptor expressed in HCAECs exposed to high glucose. NO level and eNOS activity were remarkably decreased, while PMN adhesion, VCAM-1 and ICAM-1 protein levels were increased significantly by S1P treatment in HCAECs exposed to high glucose and normal glucose. Blockage of S1PR2 with specific antagonist JTE-013 and small interfering RNA (siRNA) resulted in enhanced NO level and eNOS activity as well as decreased PMN adhesion, reduced protein levels of VCAM-1 and ICAM-1 induced by S1P. Furthermore, Phosphor-PI3K and phosphor-Akt level were markedly increased by S1PR2 blockade in S1P-treated cells exposed to high glucose, which were suppressed by PI3K inhibitor wortmannin. In conclusion, S1P/S1PR2 mediated endothelial dysfunction partly by inhibiting PI3K/Akt signaling pathway under high glucose condition. S1PR2 blockage could ameliorate endothelial dysfunction which might provide a potential therapeutic strategy for diabetic vascular complications. PMID:26921757

  12. Upregulated WDR26 serves as a scaffold to coordinate PI3K/ AKT pathway-driven breast cancer cell growth, migration, and invasion.

    PubMed

    Ye, Yuanchao; Tang, Xiaoyun; Sun, Zhizeng; Chen, Songhai

    2016-04-01

    The phosphatidylinositol 3-kinase (PI3K)/AKT pathway transmits signals downstream of receptor tyrosine kinases and G protein-coupled receptors (GPCRs), and is one of the most dysregulated pathways in breast cancer. PI3Ks and AKTs consist of multiple isoforms that play distinct and even opposite roles in breast cancer cell growth and metastasis. However, it remains unknown how the activities of various PI3K and AKT isoforms are coordinated during breast cancer progression. Previously, we showed WDR26 is a novel WD40 protein that binds Gβγ and promotes Gβγ signaling. Here, we demonstrate that WDR26 is overexpressed in highly malignant breast tumor cell lines and human breast cancer samples, and that WDR26 overexpression correlates with shortened survival of breast cancer patients. In highly malignant cell lines (MDA-MB231, DU4475 and BT549), downregulation of WDR26 expression selectively alleviated GPCR- but not EGF receptor-stimulated PI3K/AKT signaling and tumor cell growth, migration and invasion. In contrast, in a less malignant cell line (MCF7), WDR26 overexpression had the opposite effect. Additional studies indicate that downstream of GPCR stimulation, WDR26 serves as a scaffold that fosters assembly of a specific signaling complex consisting of Gβγ, PI3Kβ and AKT2. In an orthotopic xenograft mouse model of breast cancer, disrupting formation of this complex, by overexpressing WDR26 mutants in MDA-MB231 cells, abrogated PI3K/AKT activation and tumor cell growth and metastasis. Together, our results identify a novel mechanism regulating GPCR-dependent activation of the PI3K/AKT signaling axis in breast tumor cells, and pinpoint WDR26 as a potential therapeutic target for breast cancer.

  13. Dual-Blocking of PI3K and mTOR Improves Chemotherapeutic Effects on SW620 Human Colorectal Cancer Stem Cells by Inducing Differentiation

    PubMed Central

    Kim, Buyun

    2016-01-01

    Cancer stem cells (CSCs) have tumor initiation, self-renewal, metastasis and chemo-resistance properties in various tumors including colorectal cancer. Targeting of CSCs may be essential to prevent relapse of tumors after chemotherapy. Phosphatidylinositol-3-kinase (PI3K) and mammalian target of rapamycin (mTOR) signals are central regulators of cell growth, proliferation, differentiation, and apoptosis. These pathways are related to colorectal tumorigenesis. This study focused on PI3K and mTOR pathways by inhibition which initiate differentiation of SW620 derived CSCs and investigated its effect on tumor progression. By using rapamycin, LY294002, and NVP-BEZ235, respectively, PI3K and mTOR signals were blocked independently or dually in colorectal CSCs. Colorectal CSCs gained their differentiation property and lost their stemness properties most significantly in dual-blocked CSCs. After treated with anti-cancer drug (paclitaxel) on the differentiated CSCs cell viability, self-renewal ability and differentiation status were analyzed. As a result dual-blocking group has most enhanced sensitivity for anti-cancer drug. Xenograft tumorigenesis assay by using immunodeficiency mice also shows that dual-inhibited group more effectively increased drug sensitivity and suppressed tumor growth compared to single-inhibited groups. Therefore it could have potent anti-cancer effects that dual-blocking of PI3K and mTOR induces differentiation and improves chemotherapeutic effects on SW620 human colorectal CSCs. PMID:26955235

  14. Trans-homophilic interaction of CADM1 activates PI3K by forming a complex with MAGuK-family proteins MPP3 and Dlg.

    PubMed

    Murakami, Shigefumi; Sakurai-Yageta, Mika; Maruyama, Tomoko; Murakami, Yoshinori

    2014-01-01

    CADM1 (Cell adhesion molecule 1), a cell adhesion molecule belonging to the immunoglobulin superfamily, is involved in cell-cell interaction and the formation and maintenance of epithelial structure. Expression of CADM1 is frequently down-regulated in various tumors derived from epithelial cells. However, the intracellular signaling pathways activated by CADM1-mediated cell adhesion remain unknown. Here, we established a cell-based spreading assay to analyze the signaling pathway specifically activated by the trans-homophilic interaction of CADM1. In the assay, MDCK cells expressing exogenous CADM1 were incubated on the glass coated with a recombinant extracellular fragment of CADM1, and the degree of cell spreading was quantified by measuring their surface area. Assay screening of 104 chemical inhibitors with known functions revealed that LY294002, an inhibitor of phosphoinositide 3-kinase (PI3K), efficiently suppressed cell spreading in a dose-dependent manner. Inhibitors of Akt and Rac1, downstream effectors of PI3K, also partially suppressed cell spreading, while the addition of both inhibitors blocked cell spreading to the same extent as did LY294002. Furthermore, MPP3 and Dlg, membrane-associated guanylate kinase homologs (MAGuK) proteins, connect CADM1 with p85 of PI3K by forming a multi-protein complex at the periphery of cells. These results suggest that trans-homophilic interaction mediated by CADM1 activates the PI3K pathway to reorganize the actin cytoskeleton and form epithelial cell structure.

  15. Trans-homophilic interaction of CADM1 activates PI3K by forming a complex with MAGuK-family proteins MPP3 and Dlg.

    PubMed

    Murakami, Shigefumi; Sakurai-Yageta, Mika; Maruyama, Tomoko; Murakami, Yoshinori

    2014-01-01

    CADM1 (Cell adhesion molecule 1), a cell adhesion molecule belonging to the immunoglobulin superfamily, is involved in cell-cell interaction and the formation and maintenance of epithelial structure. Expression of CADM1 is frequently downregulated in various tumors derived from epithelial cells. However, the intracellular signaling pathways activated by CADM1-mediated cell adhesion remain unknown. Here, we established a cell-based spreading assay to analyze the signaling pathway specifically activated by the trans-homophilic interaction of CADM1. In the assay, MDCK cells expressing exogenous CADM1 were incubated on the glass coated with a recombinant extracellular fragment of CADM1, and the degree of cell spreading was quantified by measuring their surface area. Assay screening of 104 chemical inhibitors with known functions revealed that LY294002, an inhibitor of phosphoinositide 3-kinase (PI3K), efficiently suppressed cell spreading in a dose-dependent manner. Inhibitors of Akt and Rac1, downstream effectors of PI3K, also partially suppressed cell spreading, while the addition of both inhibitors blocked cell spreading to the same extent as did LY294002. Furthermore, MPP3 and Dlg, membrane-associated guanylate kinase homologs (MAGuK) proteins, connect CADM1 with p85 of PI3K by forming a multi-protein complex at the periphery of cells. These results suggest that trans-homophilic interaction mediated by CADM1 activates the PI3K pathway to reorganize the actin cytoskeleton and form epithelial cell structure.

  16. α-2,8-Sialyltransferase Is Involved in the Development of Multidrug Resistance via PI3K/Akt Pathway in Human Chronic Myeloid Leukemia.

    PubMed

    Zhang, Xu; Dong, Weijie; Zhou, Huimin; Li, Hongshuai; Wang, Ning; Miao, Xiaoyan; Jia, Li

    2015-02-01

    Cell surface sialylation is emerging as an important feature of cancer cell multidrug resistance (MDR). We have focused on the influence of 2,8-sialyltransferases in key steps of the development of MDR in chronic myeloid leukemia (CML). The expressional profiles of six α-2,8-sialyltransferases were generated in three pairs of CML cell lines and peripheral blood mononuclear cells (PBMC) of CML patients. Cellular MDR phenotype positively correlated with ST8SIA4 and ST8SIA6 levels. Furthermore, ST8SIA4 mediated the activity of phosphoinositide-3 kinase (PI3K)/Akt signal pathway and the expression of P-glycoprotein (P-gp). Targeting the PI3K/Akt pathway by its specific inhibitor LY294002, or by Akt RNA interfering reversed the MDR phenotype of K562/ADR cells. Inhibition of PI3K/Akt pathway also attenuated the effects caused by the overexpression of ST8SIA4 on MDR. Therefore this study indicated that α-2,8-sialyltransferases involved in the development of MDR of CML cells probably through ST8SIA4 regulating the activity of PI3K/Akt signaling and the expression of P-gp. PMID:25855199

  17. The role of the PI3K/Akt/mTOR signalling pathway in human cancers induced by infection with human papillomaviruses.

    PubMed

    Zhang, Lifang; Wu, Jianhong; Ling, Ming Tat; Zhao, Liang; Zhao, Kong-Nan

    2015-01-01

    Infection with Human papillomaviruses (HPVs) leads to the development of a wide-range of cancers, accounting for 5% of all human cancers. A prominent example is cervical cancer, one of the leading causes of cancer death in women worldwide. It has been well established that tumor development and progression induced by HPV infection is driven by the sustained expression of two oncogenes E6 and E7. The expression of E6 and E7 not only inhibits the tumor suppressors p53 and Rb, but also alters additional signalling pathways that may be equally important for transformation. Among these pathways, the phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signalling cascade plays a very important role in HPV-induced carcinogenesis by acting through multiple cellular and molecular events. In this review, we summarize the frequent amplification of PI3K/Akt/mTOR signals in HPV-induced cancers and discuss how HPV oncogenes E6/E7/E5 activate the PI3K/Akt/mTOR signalling pathway to modulate tumor initiation and progression and affect patient outcome. Improvement of our understanding of the mechanism by which the PI3K/Akt/mTOR signalling pathway contributes to the immortalization and carcinogenesis of HPV-transduced cells will assist in devising novel strategies for preventing and treating HPV-induced cancers. PMID:26022660

  18. Ketamine affects the neurogenesis of rat fetal neural stem progenitor cells via the PI3K/Akt-p27 signaling pathway

    PubMed Central

    Dong, Chaoxuan; Rovnaghi, Cynthia R.; Anand, KJS

    2014-01-01

    Ketamine is widely used as an anesthetic, analgesic, or sedative in pediatric patients. We reported that ketamine alters the normal neurogenesis of rat fetal neural stem progenitor cells (NSPCs) in the developing brain, but the underlying mechanisms remain unknown. The PI3K-PKB/Akt (Phosphatidylinositide 3-kinases/protein kinase B) signaling pathway plays many important roles in cell survival, apoptosis, and proliferation. We hypothesized that PI3K-PKB/Akt signaling may be involved in ketamine-altered neurogenesis of cultured NSPCs in vitro. NSPCs were isolated from Sprague-Dawley rat fetuses on gestational day 17. BrdU (bromodeoxyuridine) incorporation, Ki67 staining, and differentiation tests were utilized to identify primary cultured NSPCs. Immunofluorescent staining was used to detect Akt expression, whereas, Western blots measured phosphorylated Akt and p27 expression in NSPCs exposed to different treatments. We report that cultured NSPCs had properties of neurogenesis: proliferation and neural differentiation. PKB/Akt was expressed in cultured rat fetal cortical NSPCs. Ketamine inhibited the phosphorylation of Akt and further enhanced p27 expression in cultured NSPCs. All ketamine-induced PI3K/Akt signaling changes could be recovered by NMDA (N-Methyl-D-aspartate) receptor agonist, NMDA. These data suggest that inhibition of PI3K/Akt-p27 signaling may be involved in ketamine-induced neurotoxicity in the developing brain, whereas excitatory NMDA receptor activation may reverse these effects. PMID:25231110

  19. The role of the PI3K/Akt/mTOR signalling pathway in human cancers induced by infection with human papillomaviruses.

    PubMed

    Zhang, Lifang; Wu, Jianhong; Ling, Ming Tat; Zhao, Liang; Zhao, Kong-Nan

    2015-04-17

    Infection with Human papillomaviruses (HPVs) leads to the development of a wide-range of cancers, accounting for 5% of all human cancers. A prominent example is cervical cancer, one of the leading causes of cancer death in women worldwide. It has been well established that tumor development and progression induced by HPV infection is driven by the sustained expression of two oncogenes E6 and E7. The expression of E6 and E7 not only inhibits the tumor suppressors p53 and Rb, but also alters additional signalling pathways that may be equally important for transformation. Among these pathways, the phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signalling cascade plays a very important role in HPV-induced carcinogenesis by acting through multiple cellular and molecular events. In this review, we summarize the frequent amplification of PI3K/Akt/mTOR signals in HPV-induced cancers and discuss how HPV oncogenes E6/E7/E5 activate the PI3K/Akt/mTOR signalling pathway to modulate tumor initiation and progression and affect patient outcome. Improvement of our understanding of the mechanism by which the PI3K/Akt/mTOR signalling pathway contributes to the immortalization and carcinogenesis of HPV-transduced cells will assist in devising novel strategies for preventing and treating HPV-induced cancers.

  20. Biphasic activation of PI3K/Akt and MAPK/Erk1/2 signaling pathways in bovine herpesvirus type 1 infection of MDBK cells.

    PubMed

    Zhu, Liqian; Ding, Xiuyan; Zhu, Xiaofang; Meng, Songshu; Wang, Jianye; Zhou, Hong; Duan, Qiangde; Tao, Jie; Schifferli, Dieter M; Zhu, Guoqiang

    2011-04-14

    Many viruses have been known to control key cellular signaling pathways to facilitate the virus infection. The possible involvement of signaling pathways in bovine herpesvirus type 1 (BoHV-1) infection is unknown. This study indicated that infection of MDBK cells with BoHV-1 induced an early-stage transient and a late-stage sustained activation of both phosphatidylinositol 3-kinase (PI3K)/Akt and mitogen activated protein kinases/extracellular signal-regulated kinase 1/2 (MAPK/Erk1/2) signaling pathways. Analysis with the stimulation of UV-irradiated virus indicated that the virus binding and/or entry process was enough to trigger the early phase activations, while the late phase activations were viral protein expression dependent. Biphasic activation of both pathways was suppressed by the selective inhibitor, Ly294002 for PI3K and U0126 for MAPK kinase (MEK1/2), respectively. Furthermore, treatment of MDBK cells with Ly294002 caused a 1.5-log reduction in virus titer, while U0126 had little effect on the virus production. In addition, the inhibition effect of Ly294002 mainly occurred at the post-entry stage of the virus replication cycle. This revealed for the first time that BoHV-1 actively induced both PI3K/Akt and MAPK/Erk1/2 signaling pathways, and the activation of PI3K was important for fully efficient replication, especially for the post-entry stage.

  1. Simvastatin increases excitability in the hippocampus via a PI3 kinase-dependent mechanism.

    PubMed

    Métais, C; Hughes, B; Herron, C E

    2015-04-16

    Simvastatin is an HMG-CoA reductase inhibitor commonly used in the clinic to treat hypercholesterolemia. In addition, simvastatin has been shown to cross the blood-brain barrier and pleiotropic effects of simvastatin have been reported including anti-inflammatory properties, enhancement of neurite outgrowth, and memory enhancement properties. However, little has been reported on the effects of simvastatin on basal synaptic transmission and neuronal excitability. Here we report that simvastatin increases the fEPSP, the N-methyl-D-aspartate (NMDA) receptor-mediated fEPSP using extracellular recordings in the dendritic region of the CA1 of hippocampal slices taken from 8-week-old C57Black6J mice. In addition, we found that simvastatin perfusion causes a change in the input/output curve and a decrease of the paired-pulse facilitation ratio, indicating respectively an increase of the neuronal excitability and neurotransmitter release. We have also observed that acute application of simvastatin increased the amplitude of the compound action potential in the CA1 region. Notably, using LY294002, we have demonstrated that this effect was PI3K dependent and was occluded if the animals had previously received a diet supplemented with simvastatin. We have finally shown that the simvastatin-mediated increase of the compound action potential amplitude was also present in hippocampal slices from aged mice.

  2. The p110 delta structure: mechanisms for selectivity and potency of new PI(3)K inhibitors.

    PubMed

    Berndt, Alex; Miller, Simon; Williams, Olusegun; Le, Daniel D; Houseman, Benjamin T; Pacold, Joseph I; Gorrec, Fabrice; Hon, Wai-Ching; Liu, Yi; Rommel, Christian; Gaillard, Pascale; Rückle, Thomas; Schwarz, Matthias K; Shokat, Kevan M; Shaw, Jeffrey P; Williams, Roger L

    2010-02-01

    Deregulation of the phosphoinositide-3-OH kinase (PI(3)K) pathway has been implicated in numerous pathologies including cancer, diabetes, thrombosis, rheumatoid arthritis and asthma. Recently, small-molecule and ATP-competitive PI(3)K inhibitors with a wide range of selectivities have entered clinical development. In order to understand the mechanisms underlying the isoform selectivity of these inhibitors, we developed a new expression strategy that enabled us to determine to our knowledge the first crystal structure of the catalytic subunit of the class IA PI(3)K p110 delta. Structures of this enzyme in complex with a broad panel of isoform- and pan-selective class I PI(3)K inhibitors reveal that selectivity toward p110 delta can be achieved by exploiting its conformational flexibility and the sequence diversity of active site residues that do not contact ATP. We have used these observations to rationalize and synthesize highly selective inhibitors for p110 delta with greatly improved potencies. PMID:20081827

  3. Psoralidin, An Herbal Molecule Inhibits PI3K Mediated Akt Signaling In Androgen Independent Prostate Cancer (AIPC) Cells

    PubMed Central

    Kumar, Raj; Srinivasan, Sowmyalakshmi; Koduru, Srinivas; Pahari, Pallab; Rohr, Jürgen; Kyprianou, Natasha; Damodaran, Chendil

    2008-01-01

    The protein kinase Akt plays an important role in cell proliferation and survival in many cancers, including prostate cancer. Due to its kinase activity, it serves as a molecular conduit for inhibiting apoptosis and promoting angiogenesis in most cell types. In most of the prostate tumors, Akt signaling is constitutively activated due to the deletion or mutation of the tumor suppressor PTEN, which negatively regulates PI3K through lipid phosphatase activity. Recently, we identified a natural compound, psoralidin, which inhibits Akt phosphorylation and its consequent activation in androgen independent prostate cancer cells (AIPC). Furthermore, ectopic expression of Akt renders AIPC cells resistant chemotherapy; however, psoralidin overcomes Akt-mediated resistance and induces apoptosis in AIPC cells. While dissecting the molecular events, both upstream and downstream of Akt, we found that psoralidin inhibits PI3 kinase activation and transcriptionally represses the activation of NF-κB and its target genes (Bcl-2, Survivin, and Bcl-xL, etc.), which results in the inhibition of cell viability and induction of apoptosis in PC-3 and DU-145 cells. Interestingly, psoralidin selectively targets cancer cells, without causing any toxicity to normal prostate epithelial cells. In vivo xenograft assays substantiate these in vitro findings, and show psoralidin inhibits prostate tumor growth in nude mice. Our findings are of therapeutic significance in the management of prostate cancer patients with advanced or metastatic disease, as they provide new directions for the development of a phyotochemical-based platform for prevention and treatment strategies for AIPC. PMID:19223576

  4. Leishmania promastigotes activate PI3K/Akt signalling to confer host cell resistance to apoptosis.

    PubMed

    Ruhland, Aaron; Leal, Nicole; Kima, Peter E

    2007-01-01

    Previous reports have shown that cells infected with promastigotes of some Leishmania species are resistant to the induction of apoptosis. This would suggest that either parasites elaborate factors that block signalling from apoptosis inducers or that parasites engage endogenous host signalling pathways that block apoptosis. To investigate the latter scenario, we determined whether Leishmania infection results in the activation of signalling pathways that have been shown to mediate resistance to apoptosis in other infection models. First, we showed that infection with the promastigote form of Leishmania major, Leishmania pifanoi and Leishmania amazonensis activates signalling through p38 mitogen-activated protein kinase (MAPK), NFkappaB and PI3K/Akt. Then we found that inhibition of signalling through the PI3K/Akt pathway with LY294002 and Akt IV inhibitor reversed resistance of infected bone marrow-derived macrophages and RAW 264.7 macrophages to potent inducers of apoptosis. Moreover, reduction of Akt levels with small interfering RNAs to Akt resulted in the inability of infected macrophages to resist apoptosis. Further evidence of the role of PI3K/Akt signalling in the promotion of cell survival by infected cells was obtained with the finding that Bad, which is a substrate of Akt, becomes phosphorylated during the course of infection. In contrast to the observations with PI3K/Akt signalling, inhibition of p38 MAPK signalling with SB202190 or NFkappaB signalling with wedelolactone had limited effect on parasite-induced resistance to apoptosis. We conclude that Leishmania promastigotes engage PI3K/Akt signalling, which confers to the infected cell, the capacity to resist death from activators of apoptosis.

  5. Too much of a good thing: immunodeficiency due to hyperactive PI3K signaling.

    PubMed

    Walsh, Craig M; Fruman, David A

    2014-09-01

    Primary immune deficiency diseases arise due to heritable defects that often involve signaling molecules required for immune cell function. Typically, these genetic defects cause loss of gene function, resulting in primary immune deficiencies such as severe combined immune deficiency (SCID) and X-linked agammaglobulinemia (XLA); however, gain-of-function mutations may also promote immune deficiency. In this issue of the JCI, Deau et al. establish that gain-of-function mutations in PIK3R1, which encodes the p85α regulatory subunit of class IA PI3Ks, lead to immunodeficiency. These observations are consistent with previous reports that hyperactivating mutations in PIK3CD, which encodes the p110δ catalytic subunit, are capable of promoting immune deficiency. Mutations that reduce PI3K activity also result in defective lymphocyte development and function; therefore, these findings support the notion that too little or too much PI3K activity leads to immunodeficiency.

  6. Inhibition of phosphatidylinositide 3-kinase in OK-cells reduces Na/Pi-cotransport but does not interfere with its regulation by parathyroid hormone.

    PubMed

    Pfister, M F; Brunskill, N J; Forgo, J; Stange, G; Biber, J; Murer, H

    1999-08-01

    The importance of phosphatidylinositide 3- kinase(s) [PI 3-kinase(s)] in membrane trafficking processes led us to examine its/their possible role in parathyroid-hormone- (PTH-) induced endocytosis and lysosomal degradation of the type IIa Na/Pi-cotransporter in opossum kidney cells (OK-cells). We used wortmannin, a potent inhibitor of several mammalian PI 3-kinase isoforms, and measured Na/Pi-cotransporter activity and type IIa Na/Pi-cotransporter protein expression; also the induction of a negative dominant subunit (Deltap85) was used to reduce PI 3-kinase activity. Wortmannin and Deltap85 led to a reduction of Na/Pi-cotransport activity but were unable to prevent its inhibition by PTH. Wortmannin led in a dose- and time-dependent manner to a reduction of Na/Pi-cotransport activity and transporter protein expression, and retarded their recovery from PTH-induced inhibition/degradation. The data suggest that a PI 3-kinase "controlled" mechanism is involved in the synthesis (and/or routing) of the apical type IIa Na/Pi-cotransporter in OK-cells. PMID:10398872

  7. Diastereomeric mixture of calophyllic acid and isocalophyllic acid stimulates glucose uptake in skeletal muscle cells: involvement of PI-3-kinase- and ERK1/2-dependent pathways.

    PubMed

    Prasad, Janki; Maurya, Chandan Kumar; Pandey, Jyotsana; Jaiswal, Natasha; Madhur, Gaurav; Srivastava, Arvind Kumar; Narender, Tadigoppula; Tamrakar, Akhilesh Kumar

    2013-05-01

    The diastereomeric mixture of calophyllic acid and isocalophyllic acid (F015) isolated from the leaves of Calophyllum inophyllum was investigated for the metabolic effect on glucose transport in skeletal muscle cells. In L6 myotubes, F015 dose-dependently stimulated glucose uptake by increasing translocation of glucose transporter4 (GLUT4) to plasma membrane without affecting their gene expression. The effects on glucose uptake were additive to insulin. Inhibitors analyses revealed that F015-induced glucose uptake was dependent on the activation of phosphatidylinositol-3-kinase (PI-3-K) and extracellular signal-regulated kinases 1 and 2 (ERK1/2), while independent to the activation of 5'AMP-activated kinase (AMPK). F015 significantly increased the phosphorylation of AKT, AS160 and ERK1/2, account for the augmented glucose transport capacity in L6 myotubes. Furthermore, F015 improved glucose tolerance and enhanced insulin sensitivity in skeletal muscle of dexamethasone-induced insulin resistant mice. Our findings demonstrate that F015 activates glucose uptake in skeletal muscle cells through PI-3-K- and EKR1/2-dependent mechanisms and can be a potential lead for the management of diabetes and obesity.

  8. Time course of the MAPK and PI3-kinase response within 24 h of skeletal muscle overload

    NASA Technical Reports Server (NTRS)

    Carlson, C. J.; Fan, Z.; Gordon, S. E.; Booth, F. W.

    2001-01-01

    Knowledge of the molecular mechanisms by which skeletal muscle hypertrophies in response to increased mechanical loading may lead to the discovery of novel treatment strategies for muscle wasting and frailty. To gain insight into potential early signaling mechanisms associated with skeletal muscle hypertrophy, the temporal pattern of mitogen-activated protein kinase (MAPK) phosphorylation and phosphatidylinositol 3-kinase (PI3-kinase) activity during the first 24 h of muscle overload was determined in the rat slow-twitch soleus and fast-twitch plantaris muscles after ablation of the gastrocnemius muscle. p38alpha MAPK phosphorylation was elevated for the entire 24-h overload period in both muscles. In contrast, Erk 2 and p54 JNK phosphorylation were transiently increased by overload, returning to the levels of sham-operated controls by 24 h. PI3-kinase activity was increased by muscle overload only at 12 h of overload and only in the plantaris muscle. In summary, sustained elevation of p38alpha MAPK phosphorylation occurred early in response to muscle overload, identifying this pathway as a potential candidate for mediating early hypertrophic signals in response to skeletal muscle overload.

  9. Therapeutic ultrasound reverses peripheral ischemia in type 2 diabetic mice through PI3K-Akt-eNOS pathway

    PubMed Central

    Lu, Zhao-Yang; Li, Rui-Lin; Zhou, Hong-Sheng; Huang, Jing-Juan; Su, Zhi-Xiao; Qi, Jia; Zhang, Lan; Li, Yue; Shi, Yi-Qin; Hao, Chang-Ning; Duan, Jun-Li

    2016-01-01

    Therapeutic ultrasound (TUS) has been demonstrated to improve endothelial nitric oxide synthase (eNOS) activity, which played a crucial role in the regulation of angiogenesis. Diabetes Mellitus (DM) impairs eNOS activity. We tested the hypothesis that DM may retard unilateral hindlimb ischemia-induced angiogenesis by inhibiting eNOS in high-fat diet (HFD)/streptozocin (STZ) induced diabetic mice, and that TUS may reverse DM-related impairment of angiogenesis. C57BL/6 mice were allocated to four groups: (A) mice were fed standard diet (control); (B) mice were fed standard diet and treated with TUS (control+TUS); (C) type-2 DM mice were induced by HFD/STZ (diabetic); and (D) type-2 DM mice and treated with TUS (dabetic+TUS). All mice were surgically induced unilateral limb ischemia. The ischemic skeletal muscles in groups B and D were irradiated with extracorporeal TUS for 9 minutes/day (frequency of 1 MHz, intensity of 0.3 W/cm2) for 14 consecutive days. The result showed that TUS augmented the blood perfusion, increased capillary density accompanied by an upregulation of angiogenic factors and a downregulation of apoptotic proteins in group D relative to group C. In vitro, TUS inhibited the apoptosis, promoted tubule formation, proliferation and migration capacities, increased angiogenic factors expression and reduced apoptotic protein levels in human umbilical vein endothelial cells (HUVECs). Furthermore, TUS can robust reverse the inhibiting effect induced by high glucose (HG) on HUVECs, and these benefits could be blocked by phosphoinositide 3-kinase (PI3K) inhibitor (LY294002) or eNOS inhibitor (L-NAME). Together, TUS restored type-2 DM-mediated inhibition of ischemia-induced angiogenesis, partially via PI3K-Akt-eNOS signal pathway. PMID:27725849

  10. Acute anorexigenic action of leptin in rainbow trout is mediated by the hypothalamic Pi3k pathway.

    PubMed

    Gong, Ningping; Jönsson, Elisabeth; Björnsson, Björn Thrandur

    2016-04-01

    Leptin (Lep) is an anorexigenic hormone and regulates appetite-related neuropeptides in mammals. A number of neuropeptides have also been linked to appetite regulation in teleost fish, but Lep signaling activation and effects on appetite-regulating neurons are poorly elucidated in early vertebrates. This study uses cellular, tissue and organismal approaches to elucidate the acute, central Lep action in rainbow trout. The results demonstrate that Lep activates phosphorylation of protein kinase B (Akt) and signal transducer and activator of transcription 3 in rainbow trout hypothalamus-derived cells, and that the phosphatidylinositol-3-kinase (Pi3k) inhibitor LY294002 can suppress the Lep-induced Akt phosphorylation. Intracerebroventricular (ICV) Lep administration strongly suppresses food intake at the doses of 0.05 and 0.5 µg Lep fish(-1) At low dose, Lep stimulates hypothalamic transcription of anorexigenic cocaine- and amphetamine-regulated transcript (Cart) and orexigenic neuropeptide Y. At high dose, Lep stimulates hypothalamic transcription of anorexigenic proopiomelanocortin (Pomc) A1, A2, and B, while coinjection with LY294002 reverses this upregulation. The data suggest that the anorexigenic action of Lep in rainbow trout is mediated through stimulation of the anorexigenic neuropeptides Pomc and Cart. Furthermore, ICV Lep treatment increases phosphor-Akt-immunoreactive cells in the nucleus lateralis tuberis, periventricular zone along infundibulum, and lateral recess surrounded by nucleus anterior tuberis, while LY294002 inhibits this effect. Lep receptor-immunoreactive cells are also predominant in these regions. These results demonstrate that Lep activates the Pi3k-Akt pathway in the lateral tuberal hypothalamus of rainbow trout for acute appetite regulation, indicating the conservation of anorexigenic Lep action in the mediobasal hypothalamus.

  11. Erythropoietin-mediated protection of insect brain neurons involves JAK and STAT but not PI3K transduction pathways.

    PubMed

    Miljus, N; Heibeck, S; Jarrar, M; Micke, M; Ostrowski, D; Ehrenreich, H; Heinrich, R

    2014-01-31

    The cytokine erythropoietin (Epo) initiates adaptive cellular responses to both moderate environmental challenges and tissue damaging insults in various non-hematopoietic mammalian tissues including the nervous system. Neuroprotective and neuroregenerative functions of Epo in mammals are mediated through receptor-associated Janus kinase 2 and intracellular signaling cascades that modify the transcription of Epo-regulated genes. Signal transducers and activators of transcription (STAT) and phosphoinositol-3-kinase (PI3K) represent key components of two important Epo-induced transduction pathways. Our previous study on insects revealed neuroprotective and regenerative functions of recombinant human Epo (rhEpo) similar to those in mammalian nervous tissues. Here we demonstrate that rhEpo effectively rescues primary cultured locust brain neurons from apoptotic cell death induced by hypoxia or the chemical compound H-7. The Janus kinase inhibitor AG-490 and the STAT inhibitor sc-355797 abolished protective effects of rhEpo on locust brain neurons. In contrast, inhibition of PI3K with LY294002 had no effect on rhEpo-mediated neuroprotection. The results indicate that rhEpo mediates the protection of locust brain neurons through interference with apoptotic pathways by the activation of a Janus kinase-associated receptor and STAT transcription factor(s). The involvement of similar transduction pathways in mammals and insects for the mediation of neuroprotection and support of neural regeneration by Epo indicates that an Epo/Epo receptor-like signaling system with high structural and functional similarity exists in both groups of animals. Epo-like signaling involved in tissue protection appears to be an ancient beneficial function shared by vertebrates and invertebrates. PMID:24269933

  12. Major vault protein supports glioblastoma survival and migration by upregulating the EGFR/PI3K signalling axis

    PubMed Central

    Lötsch, Daniela; Steiner, Elisabeth; Holzmann, Klaus; Spiegl-Kreinecker, Sabine; Pirker, Christine; Hlavaty, Juraj; Petznek, Helga; Hegedus, Balazs; Garay, Tamas; Mohr, Thomas; Sommergruber, Wolfgang; Grusch, Michael; Berger, Walter

    2013-01-01

    Despite their ubiquitous expression and high conservation during evolution, precise cellular functions of vault ribonucleoparticles, mainly built of multiple major vault protein (MVP) copies, are still enigmatic. With regard to cancer, vaults were shown to be upregulated during drug resistance development as well as malignant transformation and progression. Such in a previous study we demonstrated that human astrocytic brain tumours including glioblastoma are generally high in vault levels while MVP expression in normal brain is comparably low. However a direct contribution to the malignant phenotype in general and that of glioblastoma in particular has not been established so far. Thus we address the questions whether MVP itself has a pro-tumorigenic function in glioblastoma. Based on a large tissue collection, we re-confirm strong MVP expression in gliomas as compared to healthy brain. Further, the impact of MVP on human glioblastoma aggressiveness was analysed by using gene transfection, siRNA knock-down and dominant-negative genetic approaches. Our results demonstrate that MVP/vaults significantly support migratory and invasive competence as well as starvation resistance of glioma cells in vitro and in vivo. The enhanced aggressiveness was based on MVP-mediated stabilization of the epidermal growth factor receptor (EGFR)/phosphatidyl-inositol-3-kinase (PI3K) signalling axis. Consequently, MVP overexpression resulted in enhanced growth and brain invasion in human glioblastoma xenograft models. Our study demonstrates, for the first time, that vaults have a tumour-promoting potential by stabilizing EGFR/PI3K-mediated migration and survival pathways in human glioblastoma. PMID:24243798

  13. Silica nanoparticles induce autophagy and endothelial dysfunction via the PI3K/Akt/mTOR signaling pathway.

    PubMed

    Duan, Junchao; Yu, Yongbo; Yu, Yang; Li, Yang; Wang, Ji; Geng, Weijia; Jiang, Lizhen; Li, Qiuling; Zhou, Xianqing; Sun, Zhiwei

    2014-01-01

    Although nanoparticles have a great potential for biomedical applications, there is still a lack of a correlative safety evaluation on the cardiovascular system. This study is aimed to clarify the biological behavior and influence of silica nanoparticles (Nano-SiO2) on endothelial cell function. The results showed that the Nano-SiO2 were internalized into endothelial cells in a dose-dependent manner. Monodansylcadaverine staining, autophagic ultrastructural observation, and LC3-I/LC3-II conversion were employed to verify autophagy activation induced by Nano-SiO2, and the whole autophagic process was also observed in endothelial cells. In addition, the level of nitric oxide (NO), the activities of NO synthase (NOS) and endothelial (e)NOS were significantly decreased in a dose-dependent way, while the activity of inducible (i)NOS was markedly increased. The expression of C-reactive protein, as well as the production of proinflammatory cytokines (tumor necrosis factor α, interleukin [IL]-1β, and IL-6) were significantly elevated. Moreover, Nano-SiO2 had an inhibitory effect on the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway. Our findings demonstrated that Nano-SiO2 could disturb the NO/NOS system, induce inflammatory response, activate autophagy, and eventually lead to endothelial dysfunction via the PI3K/Akt/mTOR pathway. This indicates that exposure to Nano-SiO2 is a potential risk factor for cardiovascular diseases.

  14. Cabazitaxel-induced autophagy via the PI3K/Akt/mTOR pathway contributes to A549 cell death

    PubMed Central

    Huo, Ruichao; Wang, Lili; Liu, Peijuan; Zhao, Yong; Zhang, Caiqin; Bai, Bing; Liu, Xueying; Shi, Changhong; Wei, Sanhua; Zhang, Hai

    2016-01-01

    Cabazitaxel has been used to treat castration-resistant prostate cancer since its approval by the US Food and Drug Administration in 2010. However, whether cabazitaxel may inhibit the proliferation of other tissue-derived cancer cells, and its underlying mechanism, remains unknown. In the present study, the A549 lung adenocarcinoma cancer cell line was exposed to cabazitaxel, in order to investigate its cytotoxic effect and determine the underlying mechanism. The results demonstrated that cabazitaxel was able to induce autophagy in A549 cells, as evidenced by the formation of autophagosomes, upregulated LC3-II expression and increased LC3 puncta. Cabazitaxel-induced autophagy had a cytotoxic effect on A549 cells, as evidenced by the induction of cell death and cell cycle arrest at G2/M phase, which was independent of the apoptotic pathway. Furthermore, transfection with Beclin1 small interfering RNA and treatment with the autophagy inhibitor 3-methyladenine protected cells from cabazitaxel-induced cell death, thus confirming that cabazitaxel-induced autophagy contributed to A549 cell death. In addition, cabazitaxel targeted the phosphoinositide 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway to induce autophagy, as indicated by reduced phosphorylation of Akt and mTOR. In conclusion, the present study demonstrated that cabazitaxel exerts a cytotoxic effect on A549 cells by acting on the PI3K/Akt/mTOR pathway to promote autophagic cell death. This result supports the potential use of cabazitaxel as a chemotherapeutic agent for the treatment of lung cancer. PMID:27572899

  15. Chloroquine or Chloroquine-PI3K/Akt Pathway Inhibitor Combinations Strongly Promote γ-Irradiation-Induced Cell Death in Primary Stem-Like Glioma Cells

    PubMed Central

    Firat, Elke; Weyerbrock, Astrid; Gaedicke, Simone; Grosu, Anca-Ligia; Niedermann, Gabriele

    2012-01-01

    We asked whether inhibitors of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway, which is highly active in cancer stem cells (CSCs) and upregulated in response to genotoxic treatments, promote γ-irradiationγIR)-induced cell death in highly radioresistant, patient-derived stem-like glioma cells (SLGCs). Surprisingly, in most cases the inhibitors did not promote γIR-induced cell death. In contrast, the strongly cytostatic Ly294002 and PI-103 even tended to reduce it. Since autophagy was induced we examined whether addition of the clinically applicable autophagy inhibitor chloroquine (CQ) would trigger cell death in SLGCs. Triple therapy with CQ at doses as low as 5 to 10 µM indeed caused strong apoptosis. At slightly higher doses, CQ alone strongly promoted γIR-induced apoptosis in all SLGC lines examined. The strong apoptosis in combinations with CQ was invariably associated with strong accumulation of the autophagosomal marker LC3-II, indicating inhibition of late autophagy. Thus, autophagy-promoting effects of PI3K/Akt pathway inhibitors apparently hinder cell death induction in γ-irradiated SLGCs. However, as we show here for the first time, the late autophagy inhibitor CQ strongly promotes γIR-induced cell death in highly radioresistant CSCs, and triple combinations of CQ, γIR and a PI3K/Akt pathway inhibitor permit reduction of the CQ dose required to trigger cell death. PMID:23091617

  16. Structure-based optimization leads to the discovery of NSC765844, a highly potent, less toxic and orally efficacious dual PI3K/mTOR inhibitor.

    PubMed

    Han, Jinsong; Chen, Ying; Yang, Chao; Liu, Ting; Wang, Mingping; Xu, Haojie; Zhang, Ling; Zheng, Canhui; Song, Yunlong; Zhu, Ju

    2016-10-21

    The phosphoinositide 3-kinase (PI3K) family is one of the most frequently activated enzymes in a wide range of human cancers; thus, inhibition of PI3K represents a promising strategy for cancer therapy. Herein, a series of benzylamine substituted arylsulfonamides were designed and synthesized as dual PI3K/mTOR inhibitors using a strategy integrating focused library design and virtual screening, resulting in the discovery of 13b (NSC765844). The compound 13b exhibits highly potent enzyme inhibition with IC50s of 1.3, 1.8, 1.5, 3.8 and 3.8 nM for PI3Kα, β, γ, δ, and mTOR, respectively. 13b was further evaluated in NCI by an in vitro cytotoxic screening program. Broad-spectrum antitumor activities with mean GI50 value of 18.6 nM against approximately 60 human tumor cell lines were found. 13b displayed favorable physicochemical properties and superior pharmacokinetic profiles for animal studies. It significantly inhibited tumor growth when administered orally in an A549 non-small-cell lung carcinoma xenograft and BEL7404 human hepatocellular carcinoma xenograft models. On the basis of its excellent in vivo efficacy and superior pharmacokinetic profiles, 13b has been selected for further preclinical investigation as a promising anticancer drug candidate. PMID:27448924

  17. A Cross-Species Study of PI3K Protein-Protein Interactions Reveals the Direct Interaction of P85 and SHP2

    NASA Astrophysics Data System (ADS)

    Breitkopf, Susanne B.; Yang, Xuemei; Begley, Michael J.; Kulkarni, Meghana; Chiu, Yu-Hsin; Turke, Alexa B.; Lauriol, Jessica; Yuan, Min; Qi, Jie; Engelman, Jeffrey A.; Hong, Pengyu; Kontaridis, Maria I.; Cantley, Lewis C.; Perrimon, Norbert; Asara, John M.

    2016-02-01

    Using a series of immunoprecipitation (IP) – tandem mass spectrometry (LC-MS/MS) experiments and reciprocal BLAST, we conducted a fly-human cross-species comparison of the phosphoinositide-3-kinase (PI3K) interactome in a drosophila S2R+ cell line and several NSCLC and human multiple myeloma cell lines to identify conserved interacting proteins to PI3K, a critical signaling regulator of the AKT pathway. Using H929 human cancer cells and drosophila S2R+ cells, our data revealed an unexpected direct binding of Corkscrew, the drosophila ortholog of the non-receptor protein tyrosine phosphatase type II (SHP2) to the Pi3k21B (p60) regulatory subunit of PI3K (p50/p85 human ortholog) but no association with Pi3k92e, the human ortholog of the p110 catalytic subunit. The p85-SHP2 association was validated in human cell lines, and formed a ternary regulatory complex with GRB2-associated-binding protein 2 (GAB2). Validation experiments with knockdown of GAB2 and Far-Western blots proved the direct interaction of SHP2 with p85, independent of adaptor proteins and transfected FLAG-p85 provided evidence that SHP2 binding on p85 occurred on the SH2 domains. A disruption of the SHP2-p85 complex took place after insulin/IGF1 stimulation or imatinib treatment, suggesting that the direct SHP2-p85 interaction was both independent of AKT activation and positively regulates the ERK signaling pathway.

  18. Taselisib (GDC-0032), a Potent β-Sparing Small Molecule Inhibitor of PI3K, Radiosensitizes Head and Neck Squamous Carcinomas Containing Activating PIK3CA Alterations

    PubMed Central

    Zumsteg, Zachary S.; Morse, Natasha; Krigsfeld, Gabriel; Gupta, Gaorav; Higginson, Daniel S.; Lee, Nancy Y.; Morris, Luc; Ganly, Ian; Shiao, Stephan L.; Powell, Simon N.; Chung, Christine H.; Scaltriti, Maurizio; Baselga, José

    2016-01-01

    Purpose Activating PIK3CA genomic alterations are frequent in head and neck squamous cell carcinoma (HNSCC), and there is an association between phosphoinositide 3-kinase (PI3K) signaling and radioresistance. Hence, we investigated the therapeutic efficacy of inhibiting PI3K with GDC-0032, a PI3K inhibitor with potent activity against p110α, in combination with radiation in HNSCC. Experimental Design The efficacy of GDC-0032 was assessed in vitro in 26 HNSCC cell lines with crystal violet proliferation assays, and changes in PI3K signaling were measured by Western blot analysis. Cytotoxicity and radiosensitization were assessed with Annexin V staining via flow cytometry and clonogenic survival assays, respectively. DNA damage repair was assessed with immunofluorescence for γH2AX foci, and cell cycle analysis was performed with flow cytometry. In vivo efficacy of GDC-0032 and radiation was assessed in xenografts implanted into nude mice. Results GDC-0032 inhibited potently PI3K signaling and displayed greater antiproliferative activity in HNSCC cell lines with PIK3CA mutations or amplification, whereas cell lines with PTEN alterations were relatively resistant to its effects. Pretreatment with GDC-0032 radiosensitized PIK3CA-mutant HNSCC cells, enhanced radiation-induced apoptosis, impaired DNA damage repair, and prolonged G2–M arrest following irradiation. Furthermore, combined GDC-0032 and radiation was more effective than either treatment alone in vivo in subcutaneous xenograft models. Conclusions GDC-0032 has increased potency in HNSCC cell lines harboring PIK3CA-activating aberrations. Further, combined GDC-0032 and radiotherapy was more efficacious than either treatment alone in PIK3CA-altered HNSCC in vitro and in vivo. This strategy warrants further clinical investigation PMID:26589432

  19. Psoralidin inhibits proliferation and enhances apoptosis of human esophageal carcinoma cells via NF-κB and PI3K/Akt signaling pathways

    PubMed Central

    Jin, Zhiliang; Yan, Wei; Jin, Hui; Ge, Changzheng; Xu, Yanhua

    2016-01-01

    Esophageal cancer is the most common gastrointestinal cancer. Psoralidin exhibits antioxidant, anti-apoptotic, anti-inflammatory and antitumor effects, which result in the inhibition of cancer formation. The present study aimed to investigate the effect of psoralidin on esophageal carcinoma proliferation and growth, and to elucidate its underlying mechanism of action. The effect of psoralidin on cell proliferation was investigated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Using an annexin V-fluorescein isothiocyanate/propidium iodide apoptosis detection kit and 4′,6-diamidino-2-phenylindole staining assay, the present study demonstrated that psoralidin significantly enhanced apoptosis of human esophageal carcinoma Eca9706 cells. In addition, caspase-3 activity was analyzed with a caspase-3 colorimetric assay kit, while nuclear factor (NF)-κB activity and protein phosphatidylinositol 3-kinase (PI3K)/Akt expression were measured with an NF-κB enzyme-linked immunosorbent assay kit and western blot analysis, respectively. Eca9706 cells were treated with a PI3K agonist in order to investigate the mechanism of action of psoralidin. It was observed that psoralidin was able to decrease the proliferation and promote the cellular apoptosis of Eca9706 cells in a dose-dependent manner. Furthermore, psoralidin was also able to inhibit the caspase-3 activity of Eca9706 cells in a dose-dependent manner. In addition, psoralidin inhibited NF-κB activity and reduced PI3K and Akt protein expression in Eca9706 cells. Notably, the PI3K agonist was able to reverse the effect of psoralidin on Eca9706 cells. The results of the present study demonstrated that psoralidin was able to inhibit proliferation and enhance apoptosis of human esophageal carcinoma cells via the NF-κB and PI3K/Akt signaling pathways. PMID:27446379

  20. PI3K/Akt is involved in brown adipogenesis mediated by growth differentiation factor-5 in association with activation of the Smad pathway

    SciTech Connect

    Hinoi, Eiichi; Iezaki, Takashi; Fujita, Hiroyuki; Watanabe, Takumi; Odaka, Yoshiaki; Ozaki, Kakeru; Yoneda, Yukio

    2014-07-18

    Highlights: • Akt is preferentially phosphorylated in BAT and sWAT of aP2-GDF5 mice. • PI3K/Akt signaling is involved in GDF5-induced brown adipogenesis. • PI3K/Akt signaling regulates GDF5-induced Smad5 phosphorylation. - Abstract: We have previously demonstrated promotion by growth differentiation factor-5 (GDF5) of brown adipogenesis for systemic energy expenditure through a mechanism relevant to activating the bone morphological protein (BMP) receptor/mothers against decapentaplegic homolog (Smad)/peroxisome proliferator-activated receptor gamma co-activator 1α (PGC-1α) pathway. Here, we show the involvement of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway in brown adipogenesis mediated by GDF5. Overexpression of GDF5 in cells expressing adipocyte protein-2 markedly accelerated the phosphorylation of Smad1/5/8 and Akt in white and brown adipose tissues. In brown adipose tissue from heterozygous GDF5{sup Rgsc451} mutant mice expressing a dominant-negative (DN) GDF5 under obesogenic conditions, the basal phosphorylation of Smad1/5/8 and Akt was significantly attenuated. Exposure to GDF5 not only promoted the phosphorylation of both Smad1/5/8 and Akt in cultured brown pre-adipocytes, but also up-regulated Pgc1a and uncoupling protein-1 expression in a manner sensitive to the PI3K/Akt inhibitor Ly294002 as well as retroviral infection with DN-Akt. GDF5 drastically promoted BMP-responsive luciferase reporter activity in a Ly294002-sensitive fashion. Both Ly294002 and DN-Akt markedly inhibited phosphorylation of Smad5 in the nuclei of brown pre-adipocytes. These results suggest that PI3K/Akt signals play a role in the GDF5-mediated brown adipogenesis through a mechanism related to activation of the Smad pathway.

  1. Expression of human TFF3 in relation to growth of HT-29 cell subpopulations: involvement of PI3-K but not STAT6.

    PubMed

    Durual, Stéphane; Blanchard, Carine; Estienne, Monique; Jacquier, Marie-France; Cuber, Jean-Claude; Perrot, Valérie; Laboisse, Christian; Cuber, Jean-Claude

    2005-02-01

    The trefoil factor family (TFF) peptides 1 and 2 (TFF1 and 2) are expressed in mucus cells of the stomach, whereas TFF3 is localized in goblet cells of the intestine. In the present study, we aimed to determine whether phosphatidylinositol 3-kinase (PI3-K) or signal transducer and activator of transcription protein 6 (STAT6) is involved in the expression of goblet cell specific markers. TFF3 expression was analyzed by RT-PCR, Northern blot, and radioimmunoassay (RIA) in relation to cell growth in subclones of HT-29 cells including the CL.16E and methotrexate (MTX) cell lines, which both exhibit a phenotype of mucus-secreting intestinal cells. A 30-fold increase in TFF3 mRNA levels and a 10-fold increase in TFF3-cell content were observed between the early proliferative and the late confluency states. The levels of MUC2 and MUC3 mRNA were also increased in the course of the differentiation process. A three to fourfold increase in PI3-K and Akt activities was observed in early post-confluent cells as compared with pre-confluent cells. Exposure of pre- and post-confluent cells to LY294002, a specific PI3-K inhibitor, for 1-4 days profoundly reduced TFF3 and MUC2 expression. A marked reduction in mucin granules content was also observed in LY-treated cells. Inhibition of the mitogen-activated protein (MAP) kinase kinase (MEK) with PD98059 did not modify the course of differentiation of the goblet cell lines. Moreover, stable transfection of HT-29 CL.16E cells with a dominant negative form of STAT6 had no effect on TFF3 induction. Together, these data indicate that PI3-K promotes the expression of TFF3 and MUC2 and that the PI3-K/Akt pathway may play a pivotal role in intestinal goblet cell differentiation.

  2. A Cross-Species Study of PI3K Protein-Protein Interactions Reveals the Direct Interaction of P85 and SHP2

    NASA Astrophysics Data System (ADS)

    Breitkopf, Susanne B.; Yang, Xuemei; Begley, Michael J.; Kulkarni, Meghana; Chiu, Yu-Hsin; Turke, Alexa B.; Lauriol, Jessica; Yuan, Min; Qi, Jie; Engelman, Jeffrey A.; Hong, Pengyu; Kontaridis, Maria I.; Cantley, Lewis C.; Perrimon, Norbert; Asara, John M.

    2016-02-01

    Using a series of immunoprecipitation (IP) - tandem mass spectrometry (LC-MS/MS) experiments and reciprocal BLAST, we conducted a fly-human cross-species comparison of the phosphoinositide-3-kinase (PI3K) interactome in a drosophila S2R+ cell line and several NSCLC and human multiple myeloma cell lines to identify conserved interacting proteins to PI3K, a critical signaling regulator of the AKT pathway. Using H929 human cancer cells and drosophila S2R+ cells, our data revealed an unexpected direct binding of Corkscrew, the drosophila ortholog of the non-receptor protein tyrosine phosphatase type II (SHP2) to the Pi3k21B (p60) regulatory subunit of PI3K (p50/p85 human ortholog) but no association with Pi3k92e, the human ortholog of the p110 catalytic subunit. The p85-SHP2 association was validated in human cell lines, and formed a ternary regulatory complex with GRB2-associated-binding protein 2 (GAB2). Validation experiments with knockdown of GAB2 and Far-Western blots proved the direct interaction of SHP2 with p85, independent of adaptor proteins and transfected FLAG-p85 provided evidence that SHP2 binding on p85 occurred on the SH2 domains. A disruption of the SHP2-p85 complex took place after insulin/IGF1 stimulation or imatinib treatment, suggesting that the direct SHP2-p85 interaction was both independent of AKT activation and positively regulates the ERK signaling pathway.

  3. Mechanism of phytoestrogen puerarin-mediated cytoprotection following oxidative injury: Estrogen receptor-dependent up-regulation of PI3K/Akt and HO-1

    SciTech Connect

    Hwang, Yong Pil; Jeong, Hye Gwang

    2008-12-15

    Phytoestrogens are polyphenolic non-steroidal plant compounds with estrogen-like biological activity. The phytoestrogen puerarin, the main isoflavone glycoside found in the root of Pueraria lobata, has been used for various medicinal purposes in traditional Chinese medicines for thousands of years. Recent studies have indicated that the estrogen receptor (ER), through interaction with p85, regulates phosphoinositide 3-kinase (PI3K) activity, revealing a physiologic, non-nuclear function of ER that may be relevant in cytoprotection. In this study, we demonstrate that the phytoestrogen puerarin inhibits tert-butyl hydroperoxide (t-BHP)-induced oxidative injury via an ER-dependent G{beta}1/PI3K/Akt and heme oxygenase-1 (HO-1) pathway. Pretreatment of Hepa1c1c7 and HepG2 cells with puerarin significantly reduced t-BHP-induced caspase-3 activation and subsequent cell death. Also, puerarin up-regulated HO-1 expression and this expression conferred cytoprotection against oxidative injury induced by t-BHP. Moreover, puerarin induced Nrf2 nuclear translocation, which is upstream of puerarin-induced HO-1 expression, and PI3K activation, a pathway that is involved in induced Nrf2 nuclear translocation, HO-1 expression and cytoprotection. Puerarin-induced up-regulation of HO-1 and cytoprotection against t-BHP were abolished by silencing Nrf2 expression with specific siRNA. Also, puerarin-mediated increases in PI3K activation and HO-1 induction were reversed by co-treatment with ICI 182,780 and pertussis toxin. Taken together, these results suggest that puerarin augments cellular antioxidant defense capacity through ER-dependent HO-1 induction via the G{beta}1/PI3K/Akt-Nrf2 signaling pathway, thereby protecting cells from oxidative stress.

  4. A Cross-Species Study of PI3K Protein-Protein Interactions Reveals the Direct Interaction of P85 and SHP2

    PubMed Central

    Breitkopf, Susanne B.; Yang, Xuemei; Begley, Michael J.; Kulkarni, Meghana; Chiu, Yu-Hsin; Turke, Alexa B.; Lauriol, Jessica; Yuan, Min; Qi, Jie; Engelman, Jeffrey A.; Hong, Pengyu; Kontaridis, Maria I.; Cantley, Lewis C.; Perrimon, Norbert; Asara, John M.

    2016-01-01

    Using a series of immunoprecipitation (IP) – tandem mass spectrometry (LC-MS/MS) experiments and reciprocal BLAST, we conducted a fly-human cross-species comparison of the phosphoinositide-3-kinase (PI3K) interactome in a drosophila S2R+ cell line and several NSCLC and human multiple myeloma cell lines to identify conserved interacting proteins to PI3K, a critical signaling regulator of the AKT pathway. Using H929 human cancer cells and drosophila S2R+ cells, our data revealed an unexpected direct binding of Corkscrew, the drosophila ortholog of the non-receptor protein tyrosine phosphatase type II (SHP2) to the Pi3k21B (p60) regulatory subunit of PI3K (p50/p85 human ortholog) but no association with Pi3k92e, the human ortholog of the p110 catalytic subunit. The p85-SHP2 association was validated in human cell lines, and formed a ternary regulatory complex with GRB2-associated-binding protein 2 (GAB2). Validation experiments with knockdown of GAB2 and Far-Western blots proved the direct interaction of SHP2 with p85, independent of adaptor proteins and transfected FLAG-p85 provided evidence that SHP2 binding on p85 occurred on the SH2 domains. A disruption of the SHP2-p85 complex took place after insulin/IGF1 stimulation or imatinib treatment, suggesting that the direct SHP2-p85 interaction was both independent of AKT activation and positively regulates the ERK signaling pathway. PMID:26839216

  5. Mango polyphenolics suppressed tumor growth in breast cancer xenografts in mice: role of the PI3K/AKT pathway and associated microRNAs.

    PubMed

    Banerjee, Nivedita; Kim, Hyemee; Krenek, Kimberly; Talcott, Stephen T; Mertens-Talcott, Susanne U

    2015-08-01

    The cytotoxic and anti-inflammatory properties of mango polyphenolics including gallic acid and gallotannins have been demonstrated in numerous types of cancers. We hypothesized that the phosphoinositide 3-kinase (PI3K)/AKT pathway and the expression of related miRNAs are involved in the chemotherapeutic activities of mango polyphenolics in a mouse xenograft model for breast cancer. The objectives of this research were to determine the tumor-cytotoxic activities of mango polyphenolics and the underlying molecular mechanisms involving posttranscriptional targets in BT474 breast cancer cells and xenografts in mice. In vitro findings showed cytotoxic effects of mango polyphenolics in BT474 breast cancer cells within a concentration range of 2.5 to 20 mg/L gallic acid equivalents. Mango polyphenolics suppressed the expression of PI3K, AKT, hypoxia inducible factor-1α, and vascular endothelial growth factor (VEGF) mRNA, and pAKT, AKT, pPI3K (p85), VEGF and nuclear factor-kappa B protein levels. The involvement of miR-126 was verified by using antagomiR for miR-126, where mango reversed the effect of the antagomiR of miR-126. In vivo, the intake of mango polyphenolics decreased the tumor volume by 73% in BT474 xenograft-bearing mice compared with the control group. In addition, mango reduced the expression of nuclear factor-kappa B (p65), pAKT, pPI3K, mammalian target of rapamycin, hypoxia inducible factor-1α, and VEGF protein in athymic nude mice. A screening for miRNA expression changes confirmed that mango polyphenolics modulated the expression of cancer-associated miRNAs including miR-126 in the xenografted tumors. In summary, mango polyphenolics have a chemotherapeutic potential against breast cancer that at least in part is mediated through the PI3K/AKT pathway and miR-126.

  6. Apoptosis and inactivation of the PI3-kinase pathway by tetrocarcin A in breast cancers

    SciTech Connect

    Nakajima, Hiroo; Sakaguchi, Koichi; Fujiwara, Ikuya; Mizuta, Mitsuhiko; Tsuruga, Mie; Magae, Junji . E-mail: jmagae@sannet.ne.jp; Mizuta, Naruhiko

    2007-04-27

    A survival kinase, Akt, is a downstream factor in the phosphatidylinositide-3'-kinase-dependent pathway, which mediates many biological responses including glucose uptake, protein synthesis and the regulation of proliferation and apoptosis, which is assumed to contribute to acquisition of malignant properties of human cancers. Here we find that an anti-tumor antibiotic, tetrocarcin A, directly induces apoptosis of human breast cancer cells. The apoptosis is accompanied by the activation of a proteolytic cascade of caspases including caspase-3 and -9, and concomitantly decreases phosphorylation of Akt, PDK1, and PTEN, a tumor suppressor that regulates the activity of Akt through the dephosphorylation of polyphosphoinositides. Tetrocarcin A affected neither expression of Akt, PDK1, or PTEN, nor did it affect the expression of Bcl family members including Bcl-2, Bcl-X{sub L}, and Bax. These results suggest that tetrocarcin A could be a potent chemotherapeutic agent for human breast cancer targeting the phosphatidylinositide-3'-kinase/Akt signaling pathway.

  7. Src and PI3 K inhibitors affect the virulence factors of Entamoeba histolytica.

    PubMed

    López-Contreras, L; Hernández-Ramírez, V I; Flores-García, Y; Chávez-Munguía, B; Talamás-Rohana, P

    2013-02-01

    Protein kinases (PKs) of parasitic protozoa are being evaluated as drug targets. A large number of protein kinases within the protein kinome of Entamoeba histolytica strongly suggest that protein phosphorylation is a key component of pathogenesis regulation by this parasite. PI3 K and Src are kinases previously described in this parasite, but their role is poorly understood. Here, the effect of Src-1-inhibitor and PI3 K inhibitor (Wortmannin) on the virulence factors of E. histolytica was evaluated. Results show that both inhibitors affect the actin cytoskeleton and the amoebic movement. Also, the proteolytic activity is diminished by Wortmannin, but not by Src-inhibitor-1; however, the phagocytic capacity is diminished by Wortmannin and Src-1-inhibitor. Finally, we found that the virulence in vivo of E. histolytica is affected by Wortmannin but not by Src-1-inhibitor. This study opens the way for the design of anti-amoebic drugs based on kinase inhibition.

  8. Imbalanced PTEN and PI3K Signaling Impairs Class Switch Recombination.

    PubMed

    Chen, Zhangguo; Getahun, Andrew; Chen, Xiaomi; Dollin, Yonatan; Cambier, John C; Wang, Jing H

    2015-12-01

    Class switch recombination (CSR) generates isotype-switched Abs with distinct effector functions. B cells express phosphatase and tensin homolog (PTEN) and multiple isoforms of class IA PI3K catalytic subunits, including p110α and p110δ, whose roles in CSR remain unknown or controversial. In this article, we demonstrate a direct effect of PTEN on CSR signaling by acute deletion of Pten specifically in mature B cells, thereby excluding the developmental impact of Pten deletion. We show that mature B cell-specific PTEN overexpression enhances CSR. More importantly, we establish a critical role for p110α in CSR. Furthermore, we identify a cooperative role for p110α and p110δ in suppressing CSR. Mechanistically, dysregulation of p110α or PTEN inversely affects activation-induced deaminase expression via modulating AKT activity. Thus, our study reveals that a signaling balance between PTEN and PI3K isoforms is essential to maintain normal CSR.

  9. PI3K/AKT and ERK regulate retinoic acid-induced neuroblastoma cellular differentiation

    SciTech Connect

    Qiao, Jingbo; Paul, Pritha; Lee, Sora; Qiao, Lan; Josifi, Erlena; Tiao, Joshua R.; Chung, Dai H.

    2012-08-03

    Highlights: Black-Right-Pointing-Pointer Retinoic acid (RA) induces neuroblastoma cells differentiation, which is accompanied by G0/G1 cell cycle arrest. Black-Right-Pointing-Pointer RA resulted in neuroblastoma cell survival and inhibition of DNA fragmentation; this is regulated by PI3K pathway. Black-Right-Pointing-Pointer RA activates PI3K and ERK1/2 pathway; PI3K pathway mediates RA-induced neuroblastoma cell differentiation. Black-Right-Pointing-Pointer Upregulation of p21 is necessary for RA-induced neuroblastoma cell differentiation. -- Abstract: Neuroblastoma, the most common extra-cranial solid tumor in infants and children, is characterized by a high rate of spontaneous remissions in infancy. Retinoic acid (RA) has been known to induce neuroblastoma differentiation; however, the molecular mechanisms and signaling pathways that are responsible for RA-mediated neuroblastoma cell differentiation remain unclear. Here, we sought to determine the cell signaling processes involved in RA-induced cellular differentiation. Upon RA administration, human neuroblastoma cell lines, SK-N-SH and BE(2)-C, demonstrated neurite extensions, which is an indicator of neuronal cell differentiation. Moreover, cell cycle arrest occurred in G1/G0 phase. The protein levels of cyclin-dependent kinase inhibitors, p21 and p27{sup Kip}, which inhibit cell proliferation by blocking cell cycle progression at G1/S phase, increased after RA treatment. Interestingly, RA promoted cell survival during the differentiation process, hence suggesting a potential mechanism for neuroblastoma resistance to RA therapy. Importantly, we found that the PI3K/AKT pathway is required for RA-induced neuroblastoma cell differentiation. Our results elucidated the molecular mechanism of RA-induced neuroblastoma cellular differentiation, which may be important for developing novel therapeutic strategy against poorly differentiated neuroblastoma.

  10. PI3K-Akt1 expression and its significance in liver tissues with chronic fluorosis

    PubMed Central

    Fan, Bin; Yu, Yanni; Zhang, Ying

    2015-01-01

    This study was to explore the effect and significance of PI3K signal pathway on mechanism of liver injury in chronic fluorosis. We used 48 Sprague-Dawley rats which were randomly divided into 4 groups according to the body weight, 12 in each group, half of male and female. The control group was fed with the solid feed (the fluorine content was 1.5 mg/kg). The fluorosis animals were fed with the corn containing fluorine content of 17 mg/kg from the endemic fluorosis areas. Blocking agent LY294002 was injected in the blocking group and phosphate buffer solution was injected in the blocking control in the caudal vein with 10 mg/kg once every other day in the one week before the end of the experiment. The animals were drunk by tap water freely. The fluoride contents of urinary and skeletal were determined by the F-ion selective electrode method. The mRNA and protein expressions of PI3K, Akt1 in the liver tissues were determined by real-time polymerase chain reaction, and streptavidin-perosidase and Western blot, respectively. Results showed that fluoride contents of the urine and bone were increased in the fluorosis compared to those in the control. The expression of PI3K and Akt1 mRNA and proteins was significantly increased in fluorosis hepatocytes, and lower than that of the fluorosis in the blocking. The apoptosis and the intracellular calcium concentration were increased. Therefore, we conclude that PI3K-Akt signaling pathway may be one of the signaling pathways in the pathogenesis of liver injury caused by fluorosis. PMID:25973007

  11. PI3K-Akt1 expression and its significance in liver tissues with chronic fluorosis.

    PubMed

    Fan, Bin; Yu, Yanni; Zhang, Ying

    2015-01-01

    This study was to explore the effect and significance of PI3K signal pathway on mechanism of liver injury in chronic fluorosis. We used 48 Sprague-Dawley rats which were randomly divided into 4 groups according to the body weight, 12 in each group, half of male and female. The control group was fed with the solid feed (the fluorine content was 1.5 mg/kg). The fluorosis animals were fed with the corn containing fluorine content of 17 mg/kg from the endemic fluorosis areas. Blocking agent LY294002 was injected in the blocking group and phosphate buffer solution was injected in the blocking control in the caudal vein with 10 mg/kg once every other day in the one week before the end of the experiment. The animals were drunk by tap water freely. The fluoride contents of urinary and skeletal were determined by the F-ion selective electrode method. The mRNA and protein expressions of PI3K, Akt1 in the liver tissues were determined by real-time polymerase chain reaction, and streptavidin-perosidase and Western blot, respectively. Results showed that fluoride contents of the urine and bone were increased in the fluorosis compared to those in the control. The expression of PI3K and Akt1 mRNA and proteins was significantly increased in fluorosis hepatocytes, and lower than that of the fluorosis in the blocking. The apoptosis and the intracellular calcium concentration were increased. Therefore, we conclude that PI3K-Akt signaling pathway may be one of the signaling pathways in the pathogenesis of liver injury caused by fluorosis.

  12. Relationship between PI3K pathway and angiogenesis in CIA rat synovium

    PubMed Central

    Zou, Lin; Zhang, Guichun; Liu, Lifeng; Chen, Chen; Cao, Xuecheng; Cai, Jinfang

    2016-01-01

    To investigate the expression of hypoxia inducible factor (HIF-1α) and vascular endothelial growth factor (VEGF) in the synovium of collagen-induced arthritis (CIA) joint, and whether the PI3K pathway regulates angiogenesis in rheumatoid arthritis or not. A randomized controlled according to the principle of the rats were divided into normal control group (10 rats) and the experimental group (40 rats). The experimental group rats were established as type II collagen plus adjuvant Freund’s complete adjuvant-induced arthritis model. HIF-1α and VEGF proteins’ expression in serum of CIA rats group and normal control group were detected by ELISA. Microvessel density (MVD) in synovial tissue of CIA rats group and normal control group were detected by immunohistochemistry (IHC) staining. The protein expression of PTEN, PI3K, and AKT in synovial tissue were detected by Western Blot. Compared with normal control group, toes and ankle swelling and arthritis index (AI) of CIA rat increased, and the expression of VEGF and HIF-1α proteins in peripheral serum increased, IHC showed that MVD was significantly higher than that of the control group, and the difference was statistically significant (p<0.05). Western Blot results showed that PI3K and AKT proteins expression in CIA synovial tissue of rats increased, while the expression of PTEN protein decreased. Correlation analysis showed that VEGF and HIF-1 levels in the peripheral serum of CIA rats were positively correlated with arthritis index (AI); the contents of HIF-1α and VEGF in the peripheral serum of CIA rats were positively correlated with MVD in synovium tissue. The CIA rat model regulated the expression of HIF-1α and VEGF proteins in peripheral serum by PI3K signaling pathway, and then regulated neovascularization in RA. PMID:27508035

  13. Relationship between PI3K pathway and angiogenesis in CIA rat synovium.

    PubMed

    Zou, Lin; Zhang, Guichun; Liu, Lifeng; Chen, Chen; Cao, Xuecheng; Cai, Jinfang

    2016-01-01

    To investigate the expression of hypoxia inducible factor (HIF-1α) and vascular endothelial growth factor (VEGF) in the synovium of collagen-induced arthritis (CIA) joint, and whether the PI3K pathway regulates angiogenesis in rheumatoid arthritis or not. A randomized controlled according to the principle of the rats were divided into normal control group (10 rats) and the experimental group (40 rats). The experimental group rats were established as type II collagen plus adjuvant Freund's complete adjuvant-induced arthritis model. HIF-1α and VEGF proteins' expression in serum of CIA rats group and normal control group were detected by ELISA. Microvessel density (MVD) in synovial tissue of CIA rats group and normal control group were detected by immunohistochemistry (IHC) staining. The protein expression of PTEN, PI3K, and AKT in synovial tissue were detected by Western Blot. Compared with normal control group, toes and ankle swelling and arthritis index (AI) of CIA rat increased, and the expression of VEGF and HIF-1α proteins in peripheral serum increased, IHC showed that MVD was significantly higher than that of the control group, and the difference was statistically significant (p<0.05). Western Blot results showed that PI3K and AKT proteins expression in CIA synovial tissue of rats increased, while the expression of PTEN protein decreased. Correlation analysis showed that VEGF and HIF-1 levels in the peripheral serum of CIA rats were positively correlated with arthritis index (AI); the contents of HIF-1α and VEGF in the peripheral serum of CIA rats were positively correlated with MVD in synovium tissue. The CIA rat model regulated the expression of HIF-1α and VEGF proteins in peripheral serum by PI3K signaling pathway, and then regulated neovascularization in RA. PMID:27508035

  14. Relationship between PI3K pathway and angiogenesis in CIA rat synovium.

    PubMed

    Zou, Lin; Zhang, Guichun; Liu, Lifeng; Chen, Chen; Cao, Xuecheng; Cai, Jinfang

    2016-01-01

    To investigate the expression of hypoxia inducible factor (HIF-1α) and vascular endothelial growth factor (VEGF) in the synovium of collagen-induced arthritis (CIA) joint, and whether the PI3K pathway regulates angiogenesis in rheumatoid arthritis or not. A randomized controlled according to the principle of the rats were divided into normal control group (10 rats) and the experimental group (40 rats). The experimental group rats were established as type II collagen plus adjuvant Freund's complete adjuvant-induced arthritis model. HIF-1α and VEGF proteins' expression in serum of CIA rats group and normal control group were detected by ELISA. Microvessel density (MVD) in synovial tissue of CIA rats group and normal control group were detected by immunohistochemistry (IHC) staining. The protein expression of PTEN, PI3K, and AKT in synovial tissue were detected by Western Blot. Compared with normal control group, toes and ankle swelling and arthritis index (AI) of CIA rat increased, and the expression of VEGF and HIF-1α proteins in peripheral serum increased, IHC showed that MVD was significantly higher than that of the control group, and the difference was statistically significant (p<0.05). Western Blot results showed that PI3K and AKT proteins expression in CIA synovial tissue of rats increased, while the expression of PTEN protein decreased. Correlation analysis showed that VEGF and HIF-1 levels in the peripheral serum of CIA rats were positively correlated with arthritis index (AI); the contents of HIF-1α and VEGF in the peripheral serum of CIA rats were positively correlated with MVD in synovium tissue. The CIA rat model regulated the expression of HIF-1α and VEGF proteins in peripheral serum by PI3K signaling pathway, and then regulated neovascularization in RA.

  15. TEIF associated centrosome activity is regulated by EGF/PI3K/Akt signaling.

    PubMed

    Zhao, Jing; Zou, Yongxin; Liu, Haijing; Wang, Huali; Zhang, Hong; Hou, Wei; Li, Xin; Jia, Xinying; Zhang, Jing; Hou, Lin; Zhang, Bo

    2014-09-01

    Centrosome amplification, which is a characteristic of cancer cells, has been understood as a driving force of genetic instability in the development of cancer. In previous work, we demonstrated that TEIF (transcriptional element-interacting factor) distributes in the centrosomes and regulates centrosome status under both physiologic and pathologic conditions. Here we identify TEIF as a downstream effector in EGF/PI3K/Akt signaling. The addition of EGF or transfection of active Akt stimulates centrosome TEIF distribution, resulting in an increase of centrosome splitting and amplification, while inhibitors of either PI3K or Akt attenuate these changes in TEIF and the associated centrosome status. A consensus motif for Akt phosphorylation (RHRVLT) proved to be involved in centrosomal TEIF localization, and the 469-threonine of this motif may be phosphorylated by Akt both in vitro and in vivo. Elimination of this phosphorylated site on TEIF caused reduced centrosome distribution and centrosome splitting or amplification. Moreover, TEIF closely co-localized with C-NAP1 at the proximal ends of centrioles, and centriolar loading of TEIF stimulated by EGF/Akt could displace C-NAP1, resulting in centrosome splitting. These findings reveal linkage of the EGF/PI3K/Akt signaling pathway to regulation of centrosome status which may act as an oncogenic pathway and induce genetic instability in carcinogenesis. PMID:24769208

  16. PI3K-mediated proliferation of fibroblasts by Calendula officinalis tincture: implication in wound healing.

    PubMed

    Dinda, Manikarna; Dasgupta, Uma; Singh, Namrata; Bhattacharyya, Debasish; Karmakar, Parimal

    2015-04-01

    Calendula officinalis, a member of the Asteraceae family, is a flowering plant and has been used for its antibacterial, antifungal, antiviral, antiinflammatory, anticancer and wound healing activity. The mode of action of C. officinalis tincture on wound healing is poorly understood. Here, we investigated the role of C. officinalis tincture (CDOT) on cell viability and wound closure. C. officinalis tincture stimulated both proliferation and migration of fibroblasts in a statistically significant manner in a PI3K-dependent pathway. The increase in phosphorylation of FAK (Tyr 397) and Akt (Ser 473) was detected after treatment of CDOT. Inhibition of the PI3K pathway by wortmannin and LY294002 decreased both cell proliferation and cell migration. HPLC-ESI MS revealed the presence of flavonol glycosides as the major compounds of CDOT. Altogether, our results showed that CDOT potentiated wound healing by stimulating proliferation and migration of fibroblast in a PI3K-dependent pathway, and the identified compounds are likely to be responsible for wound healing activity.

  17. PI3K-mediated proliferation of fibroblasts by Calendula officinalis tincture: implication in wound healing.

    PubMed

    Dinda, Manikarna; Dasgupta, Uma; Singh, Namrata; Bhattacharyya, Debasish; Karmakar, Parimal

    2015-04-01

    Calendula officinalis, a member of the Asteraceae family, is a flowering plant and has been used for its antibacterial, antifungal, antiviral, antiinflammatory, anticancer and wound healing activity. The mode of action of C. officinalis tincture on wound healing is poorly understood. Here, we investigated the role of C. officinalis tincture (CDOT) on cell viability and wound closure. C. officinalis tincture stimulated both proliferation and migration of fibroblasts in a statistically significant manner in a PI3K-dependent pathway. The increase in phosphorylation of FAK (Tyr 397) and Akt (Ser 473) was detected after treatment of CDOT. Inhibition of the PI3K pathway by wortmannin and LY294002 decreased both cell proliferation and cell migration. HPLC-ESI MS revealed the presence of flavonol glycosides as the major compounds of CDOT. Altogether, our results showed that CDOT potentiated wound healing by stimulating proliferation and migration of fibroblast in a PI3K-dependent pathway, and the identified compounds are likely to be responsible for wound healing activity. PMID:25641010

  18. Axl is essential for VEGF-A-dependent activation of PI3K/Akt

    PubMed Central

    Ruan, Guo-Xiang; Kazlauskas, Andrius

    2012-01-01

    Herein, we report that vascular endothelial growth factor A (VEGF-A) engages the PI3K/Akt pathway by a previously unknown mechanism that involves three tyrosine kinases. Upon VEGF-A-dependent activation of VEGF receptor-2 (VEGFR-2), and subsequent TSAd-mediated activation of Src family kinases (SFKs), SFKs engage the receptor tyrosine kinase Axl via its juxtamembrane domain to trigger ligand-independent autophosphorylation at a pair of YXXM motifs that promotes association with PI3K and activation of Akt. Other VEGF-A-mediated signalling pathways are independent of Axl. Interfering with Axl expression or function impairs VEGF-A- but not bFGF-dependent migration of endothelial cells. Similarly, Axl null mice respond poorly to VEGF-A-induced vascular permeability or angiogenesis, whereas other agonists induce a normal response. These results elucidate the mechanism by which VEGF-A activates PI3K/Akt, and identify previously unappreciated potential therapeutic targets of VEGF-A-driven processes. PMID:22327215

  19. EMP-1 promotes tumorigenesis of NSCLC through PI3K/AKT pathway.

    PubMed

    Lai, Senyan; Wang, Guihua; Cao, Xiaonian; Li, Zhaoming; Hu, Junbo; Wang, Jing

    2012-12-01

    This study examined the role of EMP-1 in tumorigenesis of non-small cell lung carcinoma (NSCLC) and the possible mechanism. Specimens were collected from 28 patients with benign lung diseases and 28 with NSCLC, and immunohistochemically detected to evaluate the correlation of EMP-1 expression to the clinical features of NSCLC. Recombinant adenovirus was constructed to over-express EMP-1 and then infect PC9 cells. Cell proliferation was measured by Ki67 staining. Western blotting was performed to examine the effect of EMP-1 on the PI3K/AKT signaling. Moreover, tumor xenografts were established by subcutaneous injection of PC9 cell suspension (about 5×10(7)/mL in 100 μL of PBS) into the right hind limbs of athymic nude mice. The results showed EMP-1 was significantly up-regulated in NSCLC patients as compared with those with benign lung diseases. Over-expression of EMP-1 promoted proliferation of PC9 cells, which coincided with the activation of the PI3K/AKT pathway. EMP-1 promoted the growth of xenografts of PC9 cells in athymic nude mice. It was concluded that EMP-1 expression may contribute to the development and progress of NSCLC by activating PI3K/AKT pathway.

  20. p38 MAPK and PI3K/AKT Signalling Cascades inParkinson’s Disease

    PubMed Central

    Jha, Saurabh Kumar; Jha, Niraj Kumar; Kar, Rohan; Ambasta, Rashmi K; Kumar, Pravir

    2015-01-01

    Parkinson's disease (PD) is a chronic neurodegenerative condition which has the second largest incidence rate among all other neurodegenerative disorders barring Alzheimer's disease (AD). Currently there is no cure and researchers continue to probe the therapeutic prospect in cell cultures and animal models of PD. Out of the several factors contributing to PD prognosis, the role of p38 MAPK (Mitogen activated protein-kinase) and PI3K/AKT signalling module in PD brains is crucial because the impaired balance between the pro- apoptotic and anti-apoptotic pathways trigger unwanted phenotypes such as microglia activation, neuroinflammation, oxidative stress and apoptosis. These factors continue challenging the brain homeostasis in initial stages thereby essentially assisting the dopaminergic (DA) neurons towards progressive degeneration in PD. Neurotherapeutics against PD shall then be targeted against the misregulated accomplices of the p38 and PI3K/AKT cascades. In this review, we have outlined many such established mechanisms involving the p38 MAPK and PI3K/AKT pathways which can offer therapeutic windows for the rectification of aberrant DA neuronal dynamics in PD brains. PMID:26261796

  1. Constitutive Activation of PI3K in Oocyte Induces Ovarian Granulosa Cell Tumors.

    PubMed

    Kim, So-Youn; Ebbert, Katherine; Cordeiro, Marilia H; Romero, Megan M; Whelan, Kelly A; Suarez, Adrian A; Woodruff, Teresa K; Kurita, Takeshi

    2016-07-01

    Cell-cell interactions play crucial roles in the maintenance of tissue homeostasis, a loss of which often leads to varying diseases, including cancer. Here, we report that uncontrolled PI3K activity within oocytes irreversibly transforms granulosa cells (GC), causing GC tumors (GCT) through perturbed local cell communication. Previously, we reported reproductive phenotypes of transgenic mice, in which expression of constitutively active mutant PI3K was induced in primordial oocytes by Gdf9-iCre. The transgenic mice (Cre(+)) demonstrated severe ovarian phenotypes, including the overgrowth of excess ovarian follicles and anovulation. Surprisingly, the Cre(+) mice became cachectic by postnatal day 80 due to bilateral GCT. Although GCT cells proliferated independently of oocytes, local interactions with mutant PI3K-positive oocytes during early folliculogenesis were essential for the GC transformation. Growing GCT cells expressed high levels of inhibin βA and nuclear SMAD3, and the proliferation rate was positively correlated with a high activin A to inhibin A ratio. These results suggested that the tumor cells stimulated their growth through an activin A autocrine signaling pathway, a hypothesis confirmed by activin A secretion in cultured GCT cells, which proliferated in response. Although communication between the oocyte and surrounding somatic cells is critical for the normal development of ovarian follicles, perturbations in oocyte-GC communication during early folliculogenesis can induce GCT by activating an autocrine growth circuit program in GC. Cancer Res; 76(13); 3851-61. ©2016 AACR. PMID:27197196

  2. Activation of the PI3K/mTOR/AKT Pathway and Survival in Solid Tumors: Systematic Review and Meta-Analysis

    PubMed Central

    Ocana, Alberto; Vera-Badillo, Francisco; Al-Mubarak, Mustafa; Templeton, Arnoud J.; Corrales-Sanchez, Verónica; Diez-Gonzalez, Laura; Cuenca-Lopez, María D.; Seruga, Bostjan; Pandiella, Atanasio; Amir, Eitan

    2014-01-01

    Background Aberrations in the phosphatidylinositol 3-kinase (PI3K)/mammalian target of rapamycin (mTOR)/AKT pathway are common in solid tumors. Numerous drugs have been developed to target different components of this pathway. However the prognostic value of these aberrations is unclear. Methods PubMed was searched for studies evaluating the association between activation of the PI3K/mTOR/AKT pathway (defined as PI3K mutation [PIK3CA], lack of phosphatase and tensin homolog [PTEN] expression by immunohistochemistry or western-blot or increased expression/activation of downstream components of the pathway by immunohistochemistry) with overall survival (OS) in solid tumors. Published data were extracted and computed into odds ratios (OR) for death at 5 years. Data were pooled using the Mantel-Haenszel random-effect model. Results Analysis included 17 studies. Activation of the PI3K/mTOR/AKT pathway was associated with significantly worse 5-year survival (OR:2.12, 95% confidence intervals 1.42–3.16, p<0.001). Loss of PTEN expression and increased expression/activation of downstream components were associated with worse survival. No association between PIK3CA mutations and survival was observed. Differences between methods for assessing activation of the PI3K/mTOR/AKT pathway were statistically significant (p = 0.04). There was no difference in the effect of up-regulation of the pathway on survival between different cancer sites (p = 0.13). Conclusion Activation of the PI3K/AKT/mTOR pathway, especially if measured by loss of PTEN expression or increased expression/activation of downstream components is associated with poor survival. PIK3CA mutational status is not associated with adverse outcome, challenging its value as a biomarker of patient outcome or as a stratification factor for patients treated with agents acting on the PI3K/AKT/mTOR pathway. PMID:24777052

  3. Low-dose testosterone alleviates vascular damage caused by castration in male rats in puberty via modulation of the PI3K/AKT signaling pathway

    PubMed Central

    Zhao, Jing; Liu, Ge-Li; Wei, Ying; Jiang, Li-Hong; Bao, Peng-Li; Yang, Qing-Yan

    2016-01-01

    The aim of the present study was to investigate the effect of testosterone on glucolipid metabolism and vascular injury in male rats, and examine the underlying molecular mechanisms. A total of 40 male Sprague-Dawley rats were divided into a control group (n=10), high-fat-diet + castration group (n=10), high-fat-diet + castration + low dose testosterone group (n=10), and high-fat-diet + castration + high dose testosterone group (n=10). Hematoxylin and eosin staining was performed to evaluate the morphology of the thoracic aortic tissues. Immunohistochemical staining was used to detect biomarkers of the phosphoinositide 3-kinase (PI3K) signaling pathway. The mRNA and protein expression levels of PI3K, AKT, insulin receptor substrate-1 (IRS-1), glucose transporter type 4 (GLUT-4), nuclear factor (NF)-κB and tumor necrosis factor (TNF)-α in the aortas were determined using quantitative polymerase chain reaction and Western blot analyses, respectively. Apoptosis in the aortic tissues was detected using a TUNEL assay. Castration induced apoptosis in the animals fed a high-fat-diet, whereas low dose testosterone replacement ameliorated the apoptosis in the aorta. However, the levels of apoptosis was more severe following high-dose testosterone treatment. Low-dose testosterone induced upregulation in the levels of IRS-1, AKT, GLUT-4 protein, NF-κB, TNF-α and PI3K, compared with those in the animals fed a high-fat diet following castration. A high dose of testosterone resulted in a significant decrease in the levels of IRS-1, AKT, GLUT-4, NF-κB, TNF-α and PI3K. Compared with the rats in the high-fat diet + castration group, a low dose of testosterone induced upregulation in the mRNA levels of IRS-1, AKT and GLUT-4, and downregulation of the mRNA levels of NF-κB, TNF-α and PI3K. A high dose of testosterone resulted in a significant decrease in the levels of IRS-1, AKT and GLUT-4, and marked increases in the mRNA levels of NF-κB, TNF-α and PI3K, compared with the

  4. Optimal targeting of HER2-PI3K signaling in breast cancer: mechanistic insights and clinical implications.

    PubMed

    Rexer, Brent N; Arteaga, Carlos L

    2013-07-01

    The combination of a PI3K inhibitor with trastuzumab has been shown to be effective at overcoming trastuzumab resistance in models of HER2(+) breast cancer by inhibiting HER2-PI3K-FOXO-survivin signaling. In this review the potential clinical implications of these findings are discussed.

  5. PI3K/Akt/mTOR signaling pathway in cancer stem cells: from basic research to clinical application

    PubMed Central

    Xia, Pu; Xu, Xiao-Yan

    2015-01-01

    Cancer stem cells (CSCs) are a subpopulation of tumor cells that possess unique self-renewal activity and mediate tumor initiation and propagation. The PI3K/Akt/mTOR signaling pathway can be considered as a master regulator for cancer. More and more recent studies have shown the links between PI3K/Akt/mTOR signaling pathway and CSC biology. Herein, we provide a comprehensive review on the role of signaling components upstream and downstream of PI3K/Akt/mTOR signaling in CSC. In addition, we also summarize various classes of small molecule inhibitors of PI3K/Akt/mTOR signaling pathway and their clinical potential in CSC. Overall, the current available data suggest that the PI3K/Akt/mTOR signaling pathway could be a promising target for development of CSC-target drugs. PMID:26175931

  6. SECTM1 produced by tumor cells attracts human monocytes via CD7-mediated activation of the PI3K pathway.

    PubMed

    Wang, Tao; Ge, Yingbin; Xiao, Min; Lopez-Coral, Alfonso; Li, Ling; Roesch, Alexander; Huang, Catherine; Alexander, Peter; Vogt, Thomas; Xu, Xiaowei; Hwang, Wei-Ting; Lieu, Melissa; Belser, Eric; Liu, Rui; Somasundaram, Rajasekharan; Herlyn, Meenhard; Kaufman, Russel E

    2014-04-01

    Tumor-associated macrophages (TAMs) have essential roles in tumor progression and metastasis. Tumor cells recruit myeloid progenitors and monocytes to the tumor site, where they differentiate into TAMs; however, this process is not well studied in humans. Here we show that human CD7, a T-cell and NK cell receptor, is highly expressed by monocytes and macrophages. Expression of CD7 decreases in M-CSF-differentiated macrophages and in melanoma-conditioned medium-induced macrophages (MCMI/Mφ) in comparison to monocytes. A ligand for CD7, SECTM1 (secreted and transmembrane protein 1), is highly expressed in many tumors, including melanoma cells. We show that SECTM1 binds to CD7 and significantly increases monocyte migration by activation of the PI3K (phosphatidylinositol 3'-kinase) pathway. In human melanoma tissues, tumor-infiltrating macrophages expressing CD7 are present. These melanomas, with CD7-positive inflammatory cell infiltrations, frequently highly express SECTM1, including an N-terminal, soluble form, which can be detected in the sera of metastatic melanoma patients but not in normal sera. Taken together, our data demonstrate that CD7 is present on monocytes and tumor macrophages and that its ligand, SECTM1, is frequently expressed in corresponding melanoma tissues, possibly acting as a chemoattractant for monocytes to modulate the melanoma microenvironment.

  7. A natural diarylheptanoid promotes neuronal differentiation via activating ERK and PI3K-Akt dependent pathways.

    PubMed

    Tang, G; Dong, X; Huang, X; Huang, X-J; Liu, H; Wang, Y; Ye, W-C; Shi, L

    2015-09-10

    Neuronal differentiation is a critical developmental process that determines accurate synaptic connection and circuit wiring. A wide variety of naturally occurring compounds have been shown as promising drug leads for the generation and differentiation of neurons. Here we report that a diarylheptanoid from the plant Alpinia officinarum, 7-(4-hydroxyphenyl)-1-phenyl-4E-hepten-3-one (Cpd 1), exhibited potent activities in neuronal differentiation and neurite outgrowth. Cpd 1 induced differentiation of neuroblastoma Neuro-2a cells into a neuron-like morphology, and accelerated the establishment of axon-dendrite polarization of cultured hippocampal neurons. Moreover, Cpd 1 promoted neurite extension in both Neuro-2a cells and neurons. We showed that the effects of Cpd 1 on neuronal differentiation and neurite growth were specifically dependent on the activation of extracellular signal-regulated kinases (ERKs) and phosphoinositide 3-kinase (PI3K)-Akt signaling pathways. Importantly, intraperitoneal administration of Cpd 1 promoted the differentiation of new-born progenitor cells into mature neurons in the adult hippocampal dentate gyrus. Collectively, this study identifies a naturally occurring diarylheptanoid with beneficial effects on neuronal differentiation and neurite outgrowth in vitro and in vivo.

  8. A frequent kinase domain mutation that changes the interaction between PI3K[alpha] and the membrane

    SciTech Connect

    Mandelker, Diana; Gabelli, Sandra B.; Schmidt-Kittler, Oleg; Zhu, Jiuxiang; Cheong, Ian; Huang, Chuan-Hsiang; Kinzler, Kenneth W.; Vogelstein, Bert; Amzel, L. Mario

    2009-12-01

    Mutations in oncogenes often promote tumorigenesis by changing the conformation of the encoded proteins, thereby altering enzymatic activity. The PIK3CA oncogene, which encodes p110{alpha}, the catalytic subunit of phosphatidylinositol 3-kinase alpha (PI3K{alpha}), is one of the two most frequently mutated oncogenes in human cancers. We report the structure of the most common mutant of p110{alpha} in complex with two interacting domains of its regulatory partner (p85{alpha}), both free and bound to an inhibitor (wortmannin). The N-terminal SH2 (nSH2) domain of p85{alpha} is shown to form a scaffold for the entire enzyme complex, strategically positioned to communicate extrinsic signals from phosphopeptides to three distinct regions of p110{alpha}. Moreover, we found that Arg-1047 points toward the cell membrane, perpendicular to the orientation of His-1047 in the WT enzyme. Surprisingly, two loops of the kinase domain that contact the cell membrane shift conformation in the oncogenic mutant. Biochemical assays revealed that the enzymatic activity of the p110{alpha} His1047Arg mutant is differentially regulated by lipid membrane composition. These structural and biochemical data suggest a previously undescribed mechanism for mutational activation of a kinase that involves perturbation of its interaction with the cellular membrane.

  9. De novo somatic mutations in components of the PI3K-AKT3-mTOR pathway cause hemimegalencephaly

    PubMed Central

    Lee, Jeong Ho; Huynh, My; Silhavy, Jennifer L; Kim, Sangwoo; Dixon-Salazar, Tracy; Heiberg, Andrew; Scott, Eric; Bafna, Vineet; Hill, Kiley J; Collazo, Adrienne; Funari, Vincent; Russ, Carsten; Gabriel, Stacey B; Mathern, Gary W; Gleeson, Joseph G

    2015-01-01

    De novo somatic mutations in focal areas are well documented in diseases such as neoplasia but are rarely reported in malformation of the developing brain. Hemimegalencephaly (HME) is characterized by overgrowth of either one of the two cerebral hemispheres. The molecular etiology of HME remains a mystery. The intractable epilepsy that is associated with HME can be relieved by the surgical treatment hemispherectomy, allowing sampling of diseased tissue. Exome sequencing and mass spectrometry analysis in paired brain-blood samples from individuals with HME (n = 20 cases) identified de novo somatic mutations in 30% of affected individuals in the PIK3CA, AKT3 and MTOR genes. A recurrent PIK3CA c.1633G>A mutation was found in four separate cases. Identified mutations were present in 8–40% of sequenced alleles in various brain regions and were associated with increased neuronal S6 protein phosphorylation in the brains of affected individuals, indicating aberrant activation of mammalian target of rapamycin (mTOR) signaling. Thus HME is probably a genetically mosaic disease caused by gain of function in phosphatidylinositol 3-kinase (PI3K)-AKT3-mTOR signaling. PMID:22729223

  10. Girdin regulates the migration and invasion of glioma cells via the PI3K-Akt signaling pathway

    PubMed Central

    NI, WEIMIN; FANG, YAN; TONG, LEI; TONG, ZHAOXUE; YI, FUXIN; QIU, JIANWU; WANG, RUI; TONG, XIAOJIE

    2015-01-01

    Girdin, an actin-binding protein, is associated with cell migration and is expressed at high levels in glioma cells. However, the association between girdin and the development of glioma remains to be elucidated. In the present study, short-hairpin RNA technology was used to silence the gene expression of girdin. The effects of girdin silencing on glioma cell proliferation, migration and invasion were then assessed using a cell viability assay, wound-healing assay, transwell invasion assay, reverse transcription-quantitative polymerase chain reaction, western blot analysis and gelatin zymography. The results suggested that girdin silencing inhibited the proliferation, migration and invasion of glioma cells. In addition, the expression levels and activity of matrix metalloproteinase (MMP)-2 and MMP-9 were also affected by girdin silencing. Further mechanistic investigation indicated that girdin may regulate glioma cell migration and invasion through the phosphatidylinositol-3-kinase/protein kinase B (PI3K-Akt) signaling pathway. Therefore, the results of the present study provide a theoretical foundation for the development of anticancer drugs. PMID:26151295

  11. Type 2 Iodothyronine Deiodinase Activity Is Required for Rapid Stimulation of PI3K by Thyroxine in Human Umbilical Vein Endothelial Cells.

    PubMed

    Aoki, Tomoyuki; Tsunekawa, Katsuhiko; Araki, Osamu; Ogiwara, Takayuki; Nara, Makoto; Sumino, Hiroyuki; Kimura, Takao; Murakami, Masami

    2015-11-01

    Thyroid hormones (THs) exert a number of physiological effects on the cardiovascular system. Some of the nongenomic actions of T3 are achieved by cross coupling the TH receptor (TR) with the phosphatidylinositol 3-kinase (PI3K)/protein kinase Akt (Akt) pathway. We observed that both T3 and T4 rapidly stimulated Akt phosphorylation and Ras-related C3 botulinum toxin substrate 1 (Rac1) activation, which resulted in cell migration, in a PI3K-dependent manner in human umbilical vein endothelial cells (HUVECs). We identified the expression of type 2 iodothyronine deiodinase (D2), which converts T4 to T3, and TRα1 in HUVECs. D2 activity was significantly stimulated by (Bu)2cAMP in HUVECs. The blockade of D2 activity through transfection of small interfering RNA (siRNA) specific to D2 as well as by addition of iopanoic acid, a potent D2 inhibitor, abolished Akt phosphorylation, Rac activation, and cell migration induced by T4 but not by T3. The inhibition of TRα1 expression by the transfection of siRNA for TRα1 canceled Akt phosphorylation, Rac activation, and cell migration induced by T3 and T4. These findings suggest that conversion of T4 to T3 by D2 is required for TRα1/PI3K-mediated nongenomic actions of T4 in HUVECs, including stimulation of Akt phosphorylation and Rac activation, which result in cell migration. PMID:26284425

  12. Jolkinolide B induces apoptosis in MDA-MB-231 cells through inhibition of the PI3K/Akt signaling pathway.

    PubMed

    Lin, Yu; Cui, Hongxia; Xu, Huiyu; Yue, Liling; Xu, Hao; Jiang, Liyan; Liu, Jicheng

    2012-06-01

    The phosphoinositol-3-kinase (PI3K)/Akt signal transduction pathway is critically important for tumor cell growth, proliferation and apoptosis. Apoptosis activation has been reported to be a good target in cancer therapies. In this study, we have found that jolkinolide B (JB), a diterpenoid from the traditional Chinese medicinal herb Euphorbia fischeriana Steud, strongly inhibited the expression of the PI3K p85 subunit and the phosphorylation of Akt. Furthermore, we evaluated the effects of JB on the proliferation and apoptosis of MDA-MB-231 human breast cancer cells. Our results show significant induction of apoptosis in MDA-MB-231 cells incubated with JB. This effect was enhanced by combination with LY294002. In addition, treatment with JB could induce downregulation of the Bcl-2/Bax ratio, and subsequent promotion of mitochondrial release of cytochrome c and activation of caspase-3. Taken together, JB-induced apoptosis of MDA-MB-231 cells occurs through the mitochondrial pathway. Further, the PI3K/Akt signaling cascade plays a role in the induction of apoptosis in JB-treated cells. These observations suggest that JB may have therapeutic applications in the treatment of cancer.

  13. Rac1-mediated membrane raft localization of PI3K/p110β is required for its activation by GPCRs or PTEN loss

    PubMed Central

    Cizmecioglu, Onur; Ni, Jing; Xie, Shaozhen; Zhao, Jean J; Roberts, Thomas M

    2016-01-01

    We aimed to understand how spatial compartmentalization in the plasma membrane might contribute to the functions of the ubiquitous class IA phosphoinositide 3-kinase (PI3K) isoforms, p110α and p110β. We found that p110β localizes to membrane rafts in a Rac1-dependent manner. This localization potentiates Akt activation by G-protein-coupled receptors (GPCRs). Thus genetic targeting of a Rac1 binding-deficient allele of p110β to rafts alleviated the requirement for p110β-Rac1 association for GPCR signaling, cell growth and migration. In contrast, p110α, which does not play a physiological role in GPCR signaling, is found to reside in nonraft regions of the plasma membrane. Raft targeting of p110α allowed its EGFR-mediated activation by GPCRs. Notably, p110β dependent, PTEN null tumor cells critically rely upon raft-associated PI3K activity. Collectively, our findings provide a mechanistic account of how membrane raft localization regulates differential activation of distinct PI3K isoforms and offer insight into why PTEN-deficient cancers depend on p110β. DOI: http://dx.doi.org/10.7554/eLife.17635.001 PMID:27700986

  14. PTEN/PI3K/Akt/VEGF signaling and the cross talk to KRIT1, CCM2, and PDCD10 proteins in cerebral cavernous malformations.

    PubMed

    Kar, Souvik; Samii, Amir; Bertalanffy, Helmut

    2015-04-01

    Cerebral cavernous malformations (CCM) are common vascular malformation of the brain and are associated with abnormal angiogenesis. Although the exact etiology and the underlying molecular mechanism are still under investigation, recent advances in the identification of the mutations in three genes and their interactions with different signaling pathways have shed light on our understanding of CCM pathogenesis. The phosphatidylinositol 3-kinase (PI3K)/Akt pathway is known to play a major role in angiogenesis. Studies have shown that the phosphatase and tensin homologue deleted on chromosome ten (PTEN), a tumor suppressor, is an antagonist regulator of the PI3K/Akt pathway and mediates angiogenesis by activating vascular endothelial growth factor (VEGF) expression. Here, we provide an update literature review on the current knowledge of the PTEN/PI3K/Akt/VEGF signaling in angiogenesis, more importantly in CCM pathogenesis. In addition to reviewing the current literatures, this article will also focus on the structural domain of the three CCM proteins and their interacting partners. Understanding the biology of these proteins with respect to their signaling counterpart will help to guide future research towards new therapeutic targets applicable for CCM treatment.

  15. beta-Sitosterol induces G2/M arrest, endoreduplication, and apoptosis through the Bcl-2 and PI3K/Akt signaling pathways.

    PubMed

    Moon, Dong-Oh; Kim, Mun-Ock; Choi, Yung Hyun; Kim, Gi-Young

    2008-06-18

    beta-Sitosterol (SITO) is a potentially valuable candidate for cancer chemotherapy, however the cellular and molecular mechanisms responsible for its anti-cancer activity are unknown. Therefore, we attempted to elucidate the mechanisms responsible for SITO-induced anti-proliferation in human leukemia cells. Treatment with SITO increased caspase-3 activation and DNA fragmentation in U937 and HL60 cells. This effect was associated with significant G2/M arrest and endoreduplication. We also demonstrated that SITO treatment significantly increases levels of polymeric alpha-tubulin and promoted microtubule polymerization. We next elucidated that ectopic expression of Bcl-2 accelerates endoreduplication in U937 cells. Furthermore, the specific Bcl-2 inhibitor, HA14-1, prevented endoreduplication through G2 phase arrest. Interestingly, SITO treatment did not significantly promote endoreduplication or decrease cell viability in Bcl-2 null K562 cells. SITO treatment also induced a gradual increase of phosphatidyl-inositol 3-kinase (PI3K) and Akt phosphorylation. Treatment with the selective PI3K/Akt inhibitor LY29004 completely blocked endoreduplication and apoptosis in the presence of SITO. In addition, treatment with SITO-induced phosphorylation of extracellular signal-regulated protein kinase (ERK), however significance of ERK activation in the execution of apoptosis and endoreduplication is unknown. These results suggest that SITO induces endoreduplication by promoting spindle microtubule dynamics through the Bcl-2 and PI3K/Akt signaling pathways.

  16. PI3K-GLUT4 Signal Pathway Associated with Effects of EX-B3 Electroacupuncture on Hyperglycemia and Insulin Resistance of T2DM Rats

    PubMed Central

    2016-01-01

    Objectives. To explore electroacupuncture's (EA's) effects on fasting blood glucose (FBG) and insulin resistance of type 2 diabetic mellitus (T2DM) model rats and give a possible explanation for the effects. Method. It takes high fat diet and intraperitoneal injection of streptozotocin (STZ, 30 mg/kg) for model preparation. Model rats were randomly divided into T2DM Model group, EA weiwanxiashu (EX-B3) group, and sham EA group (n = 12/group). EA (2 Hz continuous wave, 2 mA, 20 min/day, 6 days/week, 4 weeks) was applied as intervention. FBG, area under curve (AUC) of oral glucose tolerance test (OGTT), insulin resistance index (HOMA-IR), pancreatic B cell function index (HOMA-B), skeletal muscle phosphorylated phosphatidylinositol-3-kinase (PI3K), glucose transporter 4 (GLUT4), and membrane GLUT4 protein expression were measured. Results. EA weiwanxiashu (EX-B3) can greatly upregulate model rat's significantly reduced skeletal muscle PI3K (Y607) and membrane GLUT4 protein expression (P < 0.01), effectively reducing model rats' FBG and AUC of OGTT (P < 0.01). The effects are far superior to sham EA group. Conclusion. EA weiwanxiashu (EX-B3) can upregulate skeletal muscle phosphorylated PI3K protein expression, to stimulate membrane translocation of GLUT4 and thereby increase skeletal muscle glucose intake to treat T2DM.

  17. Sanguinarine Induces Apoptosis of Human Oral Squamous Cell Carcinoma KB Cells via Inactivation of the PI3K/Akt Signaling Pathway.

    PubMed

    Lee, Tae Kyung; Park, Cheol; Jeong, Soon-Jeong; Jeong, Moon-Jin; Kim, Gi-Young; Kim, Wun-Jae; Choi, Yung Hyun

    2016-08-01

    Preclinical Research Sanguinarine, an alkaloid isolated from the root of Sanguinaria canadensis and other plants of the Papaveraceae family, selectively induces apoptotic cell death in a variety of human cancer cells, but its mechanism of action requires further elaboration. The present study investigated the pro-apoptotic effects of sanguinarine in human oral squamous cell carcinoma KB cells. Sanguinarine treatment increased DR5/TRAILR2 (death receptor 5/TRAIL receptor 2) expression and enhanced the activation of caspase-8 and cleavage of its substrate, Bid. Sanguinarine also induced the mitochondrial translocation of pro-apoptotic Bax, mitochondrial dysfunction, cytochrome c release to the cytosol, and activation of caspase-9 and -3. However, a pan-caspase inhibitor, z-VAD-fmk, reversed the growth inhibition and apoptosis induced by sanguinarine. Sanguinarine also suppressed the phosphorylation of phosphoinositide 3-kinase (PI3K) and Akt in KB cells, while co-treatment of cells with sanguinarine and a PI3K inhibitor revealed synergistic apoptotic effects. However, pharmacological inhibition of AMP-activated protein kinase and mitogen-activated protein kinases did not reduce or enhance sanguinarine-induced growth inhibition and apoptosis. Collectively, these findings indicate that the pro-apoptotic effects of sanguinarine in KB cells may be regulated by a caspase-dependent cascade via activation of both intrinsic and extrinsic signaling pathways and inactivation of PI3K/Akt signaling. Drug Dev Res 77 : 227-240, 2016.   © 2016 Wiley Periodicals, Inc.

  18. Rat white adipocytes activate p85/p110 PI3K and induce PM GLUT4 in response to adrenoceptor agonists or aluminum fluoride.

    PubMed

    Ohsaka, Y; Nomura, Y

    2016-03-01

    Adipocyte responses to adrenergic and ß-adrenoceptor(-AR) (adrenoceptor) regulation are not sufficiently understood, and information helpful for elucidating the adrenoceptor-responsive machinery is insufficient. Here we show by using immunoprecipitated kinase analysis with a phosphatidylinositol 3-kinase (PI3K) p85 antibody that PI3K activation was induced by treatment with 10 or 100 µM norepinephrine (NE) for 15 min or with 10 mM aluminum fluoride (AF, a guanosine triphosphate (GTP)-binding (G) protein activator) for 20 min in white adipocytes (rat epididymal adipocytes) and that treatment with pertussis toxin (PTX, a G-protein inactivator) inhibited PI3K activation induced by the 20-min treatment with AF in the cells. In addition, western blot analysis revealed that glucose transporter 4 (GLUT4) level in the adipocyte plasma membrane (PM) fraction was increased by treatment with 10 µM NE, 100 µM dobutamine (DOB, a ß1-AR agonist), or 0.1 µM CL316243 (CL, a ß3-AR agonist) for 30 min or with 10 mM AF for 20 min. NE or AF treatment triggered 2-deoxyglucose (2-DG) uptake into adipocytes under the above conditions. Our results advance the understanding of responses to adrenoceptor regulation in white adipocytes and provide possible clues for clarifying the machinery involved in adrenergic and ß-AR responses in the cells. PMID:27030626

  19. PI3K-GLUT4 Signal Pathway Associated with Effects of EX-B3 Electroacupuncture on Hyperglycemia and Insulin Resistance of T2DM Rats.

    PubMed

    Cao, Bing-Yan; Li, Rui; Tian, Huan-Huan; Ma, Yan-Jia; Hu, Xiao-Gang; Jia, Ning; Wang, Yue-Ying

    2016-01-01

    Objectives. To explore electroacupuncture's (EA's) effects on fasting blood glucose (FBG) and insulin resistance of type 2 diabetic mellitus (T2DM) model rats and give a possible explanation for the effects. Method. It takes high fat diet and intraperitoneal injection of streptozotocin (STZ, 30 mg/kg) for model preparation. Model rats were randomly divided into T2DM Model group, EA weiwanxiashu (EX-B3) group, and sham EA group (n = 12/group). EA (2 Hz continuous wave, 2 mA, 20 min/day, 6 days/week, 4 weeks) was applied as intervention. FBG, area under curve (AUC) of oral glucose tolerance test (OGTT), insulin resistance index (HOMA-IR), pancreatic B cell function index (HOMA-B), skeletal muscle phosphorylated phosphatidylinositol-3-kinase (PI3K), glucose transporter 4 (GLUT4), and membrane GLUT4 protein expression were measured. Results. EA weiwanxiashu (EX-B3) can greatly upregulate model rat's significantly reduced skeletal muscle PI3K (Y607) and membrane GLUT4 protein expression (P < 0.01), effectively reducing model rats' FBG and AUC of OGTT (P < 0.01). The effects are far superior to sham EA group. Conclusion. EA weiwanxiashu (EX-B3) can upregulate skeletal muscle phosphorylated PI3K protein expression, to stimulate membrane translocation of GLUT4 and thereby increase skeletal muscle glucose intake to treat T2DM. PMID:27656242

  20. PI3K-GLUT4 Signal Pathway Associated with Effects of EX-B3 Electroacupuncture on Hyperglycemia and Insulin Resistance of T2DM Rats

    PubMed Central

    2016-01-01

    Objectives. To explore electroacupuncture's (EA's) effects on fasting blood glucose (FBG) and insulin resistance of type 2 diabetic mellitus (T2DM) model rats and give a possible explanation for the effects. Method. It takes high fat diet and intraperitoneal injection of streptozotocin (STZ, 30 mg/kg) for model preparation. Model rats were randomly divided into T2DM Model group, EA weiwanxiashu (EX-B3) group, and sham EA group (n = 12/group). EA (2 Hz continuous wave, 2 mA, 20 min/day, 6 days/week, 4 weeks) was applied as intervention. FBG, area under curve (AUC) of oral glucose tolerance test (OGTT), insulin resistance index (HOMA-IR), pancreatic B cell function index (HOMA-B), skeletal muscle phosphorylated phosphatidylinositol-3-kinase (PI3K), glucose transporter 4 (GLUT4), and membrane GLUT4 protein expression were measured. Results. EA weiwanxiashu (EX-B3) can greatly upregulate model rat's significantly reduced skeletal muscle PI3K (Y607) and membrane GLUT4 protein expression (P < 0.01), effectively reducing model rats' FBG and AUC of OGTT (P < 0.01). The effects are far superior to sham EA group. Conclusion. EA weiwanxiashu (EX-B3) can upregulate skeletal muscle phosphorylated PI3K protein expression, to stimulate membrane translocation of GLUT4 and thereby increase skeletal muscle glucose intake to treat T2DM. PMID:27656242

  1. Gardenamide A Protects RGC-5 Cells from H₂O₂-Induced Oxidative Stress Insults by Activating PI3K/Akt/eNOS Signaling Pathway.

    PubMed

    Wang, Rikang; Peng, Lizhi; Zhao, Jiaqiang; Zhang, Laitao; Guo, Cuiping; Zheng, Wenhua; Chen, Heru

    2015-01-01

    Gardenamide A (GA) protects the rat retinal ganglion (RGC-5) cells against cell apoptosis induced by H₂O₂. The protective effect of GA was completely abrogated by the specific phosphoinositide 3-kinase (PI3K) inhibitor LY294002, and the specific protein kinase B (Akt) inhibitor Akt VIII respectively, indicating that the protective mechanism of GA is mediated by the PI3K/Akt signaling pathway. The specific extracellular signal-regulated kinase (ERK1/2) inhibitor PD98059 could not block the neuroprotection of GA. GA attenuated the levels of reactive oxygen species (ROS) and malondialdehyde (MDA) induced by H₂O₂. Western blotting showed that GA promoted the phosphorylation of ERK1/2, Akt and endothelial nitric oxide synthase (eNOS), respectively, and effectively reversed the H₂O₂-inhibited phosphorylation of these three proteins. LY294002 completely inhibited the GA-activated phosphorylation of Akt, while only partially inhibiting eNOS. This evidence implies that eNOS may be activated directly by GA. PD98059 attenuated only partially the GA-induced phosphorylation of ERK1/2 with/without the presence of H₂O₂, indicating that GA may activate ERK1/2 directly. All these results put together confirm that GA protects RGC-5 cells from H₂O₂ insults via the activation of PI3K/Akt/eNOS signaling pathway. Whether the ERK1/2 signaling pathway is involved requires further investigations.

  2. Sedanolide induces autophagy through the PI3K, p53 and NF-κB signaling pathways in human liver cancer cells.

    PubMed

    Hsieh, Shu-Ling; Chen, Chi-Tsai; Wang, Jyh-Jye; Kuo, Yu-Hao; Li, Chien-Chun; Hsieh, Lan-Chi; Wu, Chih-Chung

    2015-12-01

    Sedanolide (SN), a phthalide-like compound from celery seed oil, possesses antioxidant effects. However, the effect of SN on cell death in human liver cancer cells has yet to be determined. In this study, cell viability determination, monodansylcadaverine (MDC) fluorescent staining and immunoblot analysis were performed to determine autophagy induction and autophagy-induced protein expression changes via molecular examination after human liver cancer (J5) cells were treated with SN. Our studies demonstrate that SN suppressed J5 cell viability by inducing autophagy. Phosphoinositide 3-kinase (PI3K)-I, mammalian target of rapamycin (mTOR) and Akt protein levels decreased, whereas PI3K-III, LC3-II and Beclin-1 protein levels increased following SN treatment in J5 cells. In addition, SN treatment upregulated nuclear p53 and damage-regulated autophagy modulator (DRAM) and downregulated cytosolic p53 and Tp53-induced glycolysis and apoptosis regulator (TIGAR) expression in J5 cells. Furthermore, the cytosolic phosphorylation of inhibitor of kappa B (IκB) and nuclear p65 and the DNA-binding activity of NF-κB increased after SN treatment. These results suggest that SN induces J5 cell autophagy by regulating PI3K, p53 and NF-κB autophagy-associated signaling pathways in J5 cells. PMID:26500073

  3. Hepatocyte growth factor (HGF) enhances cardiac commitment of differentiating embryonic stem cells by activating PI3 kinase

    SciTech Connect

    Roggia, Cristiana; Ukena, Christian; Boehm, Michael; Kilter, Heiko . E-mail: kilter@med-in.uni-saarland.de

    2007-03-10

    Hepatocyte growth factor (HGF) is a pleiotropic cytokine promoting proliferation, migration and survival in several cell types. HGF and its cognate receptor c-Met are expressed in cardiac cells during early cardiogenesis, but data concerning its role in cardiac differentiation of embryonic stem cells (ESCs) and the underlying molecular mechanisms involved are limited. In the present study we show that HGF significantly increases the number of beating embryoid bodies of differentiating ESCs without affecting beating frequency. Furthermore, HGF up-regulates the expression of the cardiac-specific transcription factors Nkx 2.5 and GATA-4 and of markers of differentiated cardiomyocytes, i.e. {alpha}-MHC, {beta}-MHC, ANF, MLC2v and Troponin T. The HGF-induced increase in Nkx 2.5 expression was inhibited by co-treatment with the PI3 kinase inhibitors Wortmannin and LY294002, but not by its inactive homolog LY303511, suggesting an involvement of the PI3 kinase/Akt pathway in this effect. We conclude that HGF is an important growth factor involved in cardiac differentiation and/or proliferation of ESCs and may therefore be critical for the in vitro generation of pre- or fully differentiated cardiomyocytes as required for clinical use of embryonic stem cells in cardiac diseases.

  4. Therapeutic implications of targeting the PI3Kinase/AKT/mTOR signaling module in melanoma therapy

    PubMed Central

    Jazirehi, Ali R; Wenn, Peter B; Damavand, Mohsen

    2012-01-01

    The PI3Kinase/AKT/mTOR signaling module is implicated in various cellular functions including cell survival, growth and proliferation, glucose metabolism, apoptosis, migration, and angiogenesis. Increased expression of AKT and its up- and downstream regulators is linked to several types of cancer. Aberrant expression of AKT is observed in nearly 60% of melanomas culminating in apoptosis resistance via deactivation of apoptotic molecules Bad and Cas-pase-9. Through cross-talk with NF-κB, ERK1/2, JNK and p38MAPK signaling pathways, AKT induces a plethora of cellular effects often leading to tumor development and progression. Due to frequently observed resistance to other common cancer treatments such as chemotherapy, immunotherapy, and radiation, and the detrimental consequences of constitutive activation of the PI3Kinase/AKT/mTOR signaling module, targeted inhibition of the effectors and substrates involved in this module has become a viable and attractive option for molecular targeted therapy in melanoma. Pharmacological inhibitors of various components of this module, either alone or in combination with other agents, have shown significant decrease in proliferation, tumorigenesis, cell growth and survival of various tumors in phases I and II clinical trials. Some inhibitors have even received their Food and Drug Administration (FDA) approval. This review summarizes the current knowledge on this module, its cross-talk with other major cell survival pathways and its targeted inhibition for therapeutic purposes in melanoma. PMID:22485197

  5. The involvement of Gab1 and PI 3-kinase in {beta}1 integrin signaling in keratinocytes

    SciTech Connect

    Kuwano, Yoshihiro; Fujimoto, Manabu . E-mail: fujimoto-m@umin.ac.jp; Watanabe, Rei; Ishiura, Nobuko; Nakashima, Hiroko; Komine, Mayumi; Hamazaki, Tatsuo S.; Tamaki, Kunihiko; Okochi, Hitoshi

    2007-09-14

    The control of the stem cell compartment in epidermis is closely linked to the regulation of keratinocyte proliferation and differentiation. {beta}1 integrins are expressed 2-fold higher by stem cells than transit-amplifying cells. Signaling from these {beta}1 integrins is critical for the regulation of the epidermal stem cell compartment. To clarify the functional relevance of this differential expression of {beta}1 integrins, we established HaCaT cells with high {beta}1integrin expression by repeated flow cytometric sorting of this population from the parental cell line. In these obtained cells expressing {beta}1 integrins by 5-fold, MAPK activation was markedly increased. Regarding the upstream of MAPK, Gab1 phosphorylation was also higher with high {beta}1 integrin expression, while Shc phosphorylation was not altered. In addition, enhanced phosphatidylinositol 3-kinase activation was also observed. These observations suggest that Gab1 and phosphatidylinositol 3-kinase play pivotal roles in the {beta}1 integrin-mediated regulation of the epidermal stem cell compartment.

  6. Induction of cellular apoptosis in human breast cancer by DLBS1425, a Phaleria macrocarpa compound extract, via down-regulation of PI3-kinase/AKT pathway.

    PubMed

    Tandrasasmita, Olivia M; Lee, Jason S; Baek, Sung Hee; Tjandrawinata, Raymond R

    2010-10-15

    Phaleria macrocarpa, also known as Mahkota dewa, is an Indonesian native plant that has been used as a remedy for many diseases. However, the molecular mechanism of Phaleria macrocarpa is still limited. In this study, we evaluate its molecular mechanism using a bioactivity-guided DLBS1425, an extract of Phaleria macrocarpa on MDA-MB-231 breast cancer cell line. DLBS1425 exhibited inhibition of proliferative, migratory and invasive potential of MDA-MB-231 in a dose-dependent manner, and significantly reduced phosphoinositide-3 (PI3)-kinase/protein kinase B (AKT) signalling by reducing PI3K transcript level and subsequent reduction in AKT phosphorylation. Further, it induced pro-apoptotic genes including BAX, BAD and PUMA and consequently induces cellular death signal by caspase-9 activation, promoting PARP cleavage and DNA fragmentation. Our results suggest that DLBS1425 is a potential anticancer agent which targets genes involved in both cell survival and apoptosis in MDA-MB-231 breast cancer cells. PMID:20703095

  7. Krüppel-like factor 14 increases insulin sensitivity through activation of PI3K/Akt signal pathway.

    PubMed

    Yang, Min; Ren, Yan; Lin, Zhimin; Tang, Chenchen; Jia, Yanjun; Lai, Yerui; Zhou, Tingting; Wu, Shaobo; Liu, Hua; Yang, Gangyi; Li, Ling

    2015-11-01

    Genome-wide association studies (GWAS) have shown that Krüppel-like factor 14 (KLF14) is associated with type 2 diabetes mellitus (T2DM). However, no report has demonstrated a relationship between KLF14 and glucose metabolism. The aim of this study was to determine whether KLF14 is associated with glucose metabolism and insulin signaling in vitro. The mRNA and protein expressions of KLF14 were determined by Real-time PCR and Western blotting. Glucose uptake was assessed by 2-[(3)H]-deoxyglucose (2-DG) uptake. Western blotting was used to identify the activation of insulin signaling proteins. KLF14 mRNA and protein in fat and muscle were significantly decreased in HFD-fed mice, db/db mice and T2DM patients. Overexpression of KLF14 enhanced insulin-stimulated glucose uptake and the activation of Akt kinase in Hepa1-6 cells. The phosphorylation of insulin receptor (InsR), insulin receptor substrate-1(IRS-1), glycogen synthase kinase-3β (GSK-3β) and Akt also elevated significantly by up-regulation of KLF14. KLF14 overexpression in Hepa1-6 cells prevented the inhibition of glucose uptake and Akt phosphorylation induced by high glucose and/or high insulin, or T2DM serum. However, KLF14's ability to increase glucose uptake and Akt activation was significantly attenuated by LY294002, a PI3-kinase inhibitor. These data suggested that KLF14 could increase insulin sensitivity probably through the PI3K/Akt pathway. PMID:26226221

  8. Quercetin suppresses HeLa cells by blocking PI3K/Akt pathway.

    PubMed

    Xiang, Tao; Fang, Yong; Wang, Shi-Xuan

    2014-10-01

    To explore the effect of quercetin on the proliferation and apoptosis of HeLa cells, HeLa cells were incubated with quercetin at different concentrations. Cell viability was evaluated by MTT assay, cell apoptosis was detected by Annexin-V/PI double labeled cytometry and DNA ladder assay. Cell cycle was flow cytometrically determined and the morphological changes of the cells were observed under a fluorescence microscope after Hoechst 33258 staining and the apoptosis-related proteins in the HeLa cells were assessed by Western blotting. The results showed that quercetin significantly inhibited the growth of HeLa cells and induced obvious apoptosis in vitro in a time- and dose-dependent manner. Moreover, quercetin induced apoptosis of HeLa cells in cell cycle-dependent manner because quercetin could induce arrest of HeLa cells at G0/G1 phase. Quercetin treatment down-regulated the expression of the PI3K and p-Akt. In addition, quercetin could down-regulate expression of bcl-2, up-regulate Bax, but exerted no effect on the overall expression of Akt. We are led to conclude that quercetin induces apoptosis via PI3k/Akt pathways, and quercetin has potential to be used as an anti-tumor agent against human cervix cancer.

  9. Tripeptide SQL Inhibits Platelet Aggregation and Thrombus Formation by Affecting PI3K/Akt Signaling.

    PubMed

    Su, Xing-li; Su, Wen; He, Zhi-long; Ming, Xin; Kong, Yi

    2015-09-01

    Centipede has been prescribed for the treatment of cardiovascular diseases in Asian countries for several hundred years. Previously, a new antiplatelet tripeptide SQL (H-Ser-Gln-Leu-OH) was isolated and characterized from centipede. In this study, we investigated its antithrombotic activities in vivo and underlying mechanism. It was found that SQL inhibited platelet aggregation induced by adenosine diphosphate, thrombin, epinephrine, and collagen and attenuated thrombus formation in both the ferric chloride-induced arterial thrombosis model and arteriovenous shunt thrombosis model in rats. It did not prolong the bleeding time in mice even at the dose of 10 mg/kg that showed potent antithrombosis effects. Molecular docking revealed that SQL binds PI3Kβ with the binding free energy of -24.341 kcal/mol, which is close to that of cocrystallized ligand (-24.220 kcal/mol). Additionally, SQL displayed inhibition on the late (180 seconds) but did not influence the early (60 seconds) Akt Ser473 phosphorylation in the immunoblot assay. These results suggest that SQL inhibits thrombus formation in vivo and that SQL inhibits PI3K-mediated signaling or even the PI3K itself in platelets. This study may help elucidate the mechanism for centipede treating cardiovascular diseases. PMID:25923322

  10. Tripeptide SQL Inhibits Platelet Aggregation and Thrombus Formation by Affecting PI3K/Akt Signaling.

    PubMed

    Su, Xing-li; Su, Wen; He, Zhi-long; Ming, Xin; Kong, Yi

    2015-09-01

    Centipede has been prescribed for the treatment of cardiovascular diseases in Asian countries for several hundred years. Previously, a new antiplatelet tripeptide SQL (H-Ser-Gln-Leu-OH) was isolated and characterized from centipede. In this study, we investigated its antithrombotic activities in vivo and underlying mechanism. It was found that SQL inhibited platelet aggregation induced by adenosine diphosphate, thrombin, epinephrine, and collagen and attenuated thrombus formation in both the ferric chloride-induced arterial thrombosis model and arteriovenous shunt thrombosis model in rats. It did not prolong the bleeding time in mice even at the dose of 10 mg/kg that showed potent antithrombosis effects. Molecular docking revealed that SQL binds PI3Kβ with the binding free energy of -24.341 kcal/mol, which is close to that of cocrystallized ligand (-24.220 kcal/mol). Additionally, SQL displayed inhibition on the late (180 seconds) but did not influence the early (60 seconds) Akt Ser473 phosphorylation in the immunoblot assay. These results suggest that SQL inhibits thrombus formation in vivo and that SQL inhibits PI3K-mediated signaling or even the PI3K itself in platelets. This study may help elucidate the mechanism for centipede treating cardiovascular diseases.

  11. Activation of PI3K signaling prevents aminoglycoside-induced hair cell death in the murine cochlea.

    PubMed

    Jadali, Azadeh; Kwan, Kelvin Y

    2016-01-01

    Loss of sensory hair cells of the inner ear due to aminoglycoside exposure is a major cause of hearing loss. Using an immortalized multipotent otic progenitor (iMOP) cell line, specific signaling pathways that promote otic cell survival were identified. Of the signaling pathways identified, the PI3K pathway emerged as a strong candidate for promoting hair cell survival. In aging animals, components for active PI3K signaling are present but decrease in hair cells. In this study, we determined whether activated PI3K signaling in hair cells promotes survival. To activate PI3K signaling in hair cells, we used a small molecule inhibitor of PTEN or genetically ablated PTEN using a conditional knockout animal. Hair cell survival was challenged by addition of gentamicin to cochlear cultures. Hair cells with activated PI3K signaling were more resistant to aminoglycoside-induced hair cell death. These results indicate that increased PI3K signaling in hair cells promote survival and the PI3K signaling pathway is a target for preventing aminoglycoside-induced hearing loss.

  12. Spatially distinct roles of class Ia PI3K isoforms in the development and maintenance of PTEN hamartoma tumor syndrome

    PubMed Central

    Wang, Qi; Von, Thanh; Bronson, Roderick; Ruan, Minzi; Mu, Wenxia; Huang, Alan; Maira, Sauveur-Michel; Zhao, Jean J.

    2013-01-01

    PTEN hamartoma tumor syndrome (PHTS) comprises a collection of genetic disorders associated with germline mutations in the tumor suppressor gene PTEN. Therapeutic options and preventative measures for PHTS are limited. Using both genetically engineered mouse models and pharmacological PI3K isoform-selective inhibitors, we found that the roles of PI3K isoforms are spatially distinct in the skin: While p110α is responsible for the sustained survival of suprabasal cells of the epidermis in the absence of PTEN, p110β is important for the hyperproliferation of basal cells in PHTS. Furthermore, we identified a differential expression pattern of p110α and p110β in basal and suprabasal keratinocytes as well as differential PI3K regulation by upstream signals in the basal and suprabasal compartments of the epidermis, providing a potential molecular mechanism underlying the specific roles of PI3K isoforms in the epidermis. Finally, we demonstrate that combined inhibition of both PI3K isoforms prevents the development of PHTS and also reverses skin hamartomas that have reached advanced stages in mice. Together, these results not only advance our overall understanding of the diverse roles of PI3K isoforms, but also have the potential for meaningful translation via the clinical utilization of PI3K inhibitors for both prevention and therapy in PHTS patients. PMID:23873941

  13. Activation of PI3K signaling prevents aminoglycoside-induced hair cell death in the murine cochlea

    PubMed Central

    Jadali, Azadeh

    2016-01-01

    ABSTRACT Loss of sensory hair cells of the inner ear due to aminoglycoside exposure is a major cause of hearing loss. Using an immortalized multipotent otic progenitor (iMOP) cell line, specific signaling pathways that promote otic cell survival were identified. Of the signaling pathways identified, the PI3K pathway emerged as a strong candidate for promoting hair cell survival. In aging animals, components for active PI3K signaling are present but decrease in hair cells. In this study, we determined whether activated PI3K signaling in hair cells promotes survival. To activate PI3K signaling in hair cells, we used a small molecule inhibitor of PTEN or genetically ablated PTEN using a conditional knockout animal. Hair cell survival was challenged by addition of gentamicin to cochlear cultures. Hair cells with activated PI3K signaling were more resistant to aminoglycoside-induced hair cell death. These results indicate that increased PI3K signaling in hair cells promote survival and the PI3K signaling pathway is a target for preventing aminoglycoside-induced hearing loss. PMID:27142333

  14. PI3K inhibition synergizes with glucocorticoids but antagonizes with methotrexate in T-cell acute lymphoblastic leukemia

    PubMed Central

    Silveira, André Bortolini; Laranjeira, Angelo Brunelli Albertoni; Rodrigues, Gisele Olinto Libanio; Leal, Paulo César; Cardoso, Bruno António; Barata, João Taborda; Yunes, Rosendo Augusto; Zanchin, Nilson Ivo Tonin; Brandalise, Sílvia Regina; Yunes, José Andrés

    2015-01-01

    The PI3K pathway is frequently hyperactivated in primary T-cell acute lymphoblastic leukemia (T-ALL) cells. Activation of the PI3K pathway has been suggested as one mechanism of glucocorticoid resistance in T-ALL, and patients harboring mutations in the PI3K negative regulator PTEN may be at increased risk of induction failure and relapse. By gene expression microarray analysis of T-ALL cells treated with the PI3K inhibitor AS605240, we identified Myc as a prominent downstream target of the PI3K pathway. A significant association was found between the AS605240 gene expression signature and that of glucocorticoid resistance and relapse in T-ALL. AS605240 showed anti-leukemic activity and strong synergism with glucocorticoids both in vitro and in a NOD/SCID xenograft model of T-ALL. In contrast, PI3K inhibition showed antagonism with methotrexate and daunorubicin, drugs that preferentially target dividing cells. This antagonistic interaction, however, could be circumvented by the use of correct drug scheduling schemes. Our data indicate the potential benefits and difficulties for the incorporation of PI3K inhibitors in T-ALL therapy. PMID:25869207

  15. The Secretome of Endothelial Progenitor Cells Promotes Brain Endothelial Cell Activity through PI3-Kinase and MAP-Kinase

    PubMed Central

    Di Santo, Stefano; Seiler, Stefanie; Fuchs, Anna-Lena; Staudigl, Jennifer; Widmer, Hans Rudolf

    2014-01-01

    Background Angiogenesis and vascular remodelling are crucial events in tissue repair mechanisms promoted by cell transplantation. Current evidence underscores the importance of the soluble factors secreted by stem cells in tissue regeneration. In the present study we investigated the effects of paracrine factors derived from cultured endothelial progenitor cells (EPC) on rat brain endothelial cell properties and addressed the signaling pathways involved. Methods Endothelial cells derived from rat brain (rBCEC4) were incubated with EPC-derived conditioned medium (EPC-CM). The angiogenic response of rBCEC4 to EPC-CM was assessed as effect on cell number, migration and tubular network formation. In addition, we have compared the outcome of the in vitro experiments with the effects on capillary sprouting from rat aortic rings. The specific PI3K/AKT inhibitor LY294002 and the MEK/ERK inhibitor PD98059 were used to study the involvement of these two signaling pathways in the transduction of the angiogenic effects of EPC-CM. Results Viable cell number, migration and tubule network formation were significantly augmented upon incubation with EPC-CM. Similar findings were observed for aortic ring outgrowth with significantly longer sprouts. The EPC-CM-induced activities were significantly reduced by the blockage of the PI3K/AKT and MEK/ERK signaling pathways. Similarly to the outcome of the rBCEC4 experiments, inhibition of the PI3K/AKT and MEK/ERK pathways significantly interfered with capillary sprouting induced by EPC-CM. Conclusion The present study demonstrates that EPC-derived paracrine factors substantially promote the angiogenic response of brain microvascular endothelial cells. In addition, our findings identified the PI3K/AKT and MEK/ERK pathways to play a central role in mediating these effects. PMID:24755675

  16. Metastatic function of BMP-2 in gastric cancer cells: The role of PI3K/AKT, MAPK, the NF-{kappa}B pathway, and MMP-9 expression

    SciTech Connect

    Kang, Myoung Hee; Oh, Sang Cheul; Kang, Han Na; Kim, Jung Lim; Kim, Jun Suk

    2011-07-15

    Bone morphogenetic proteins (BMPs) have been implicated in tumorigenesis and metastatic progression in various types of cancer cells, but the role and cellular mechanism in the invasive phenotype of gastric cancer cells is not known. Herein, we determined the roles of phosphoinositide 3-kinase (PI3K)/AKT, extracellular signal-regulated protein kinase (ERK), nuclear factor (NF)-{kappa}B, and matrix metalloproteinase (MMP) expression in BMP-2-mediated metastatic function in gastric cancer. We found that stimulation of BMP-2 in gastric cancer cells enhanced the phosphorylation of AKT and ERK. Accompanying activation of AKT and ERK kinase, BMP-2 also enhanced phosphorylation/degradation of I{kappa}B{alpha} and the nuclear translocation/activation of NF-{kappa}B. Interestingly, blockade of PI3K/AKT and ERK signaling using LY294002 and PD98059, respectively, significantly inhibited BMP-2-induced motility and invasiveness in association with the activation of NF-{kappa}B. Furthermore, BMP-2-induced MMP-9 expression and enzymatic activity was also significantly blocked by treatment with PI3K/AKT, ERK, or NF-{kappa}B inhibitors. Immunohistochemistry staining of 178 gastric tumor biopsies indicated that expression of BMP-2 and MMP-9 had a significant positive correlation with lymph node metastasis and a poor prognosis. These results indicate that the BMP-2 signaling pathway enhances tumor metastasis in gastric cancer by sequential activation of the PI3K/AKT or MAPK pathway followed by the induction of NF-{kappa}B and MMP-9 activity, indicating that BMP-2 has the potential to be a therapeutic molecular target to decrease metastasis.

  17. Modulation of PI3K-LXRα-dependent lipogenesis mediated by oxidative/nitrosative stress contributes to inhibition of HCV replication by quercetin.

    PubMed

    Pisonero-Vaquero, Sandra; García-Mediavilla, María V; Jorquera, Francisco; Majano, Pedro L; Benet, Marta; Jover, Ramiro; González-Gallego, Javier; Sánchez-Campos, Sonia

    2014-03-01

    There is experimental evidence that some antioxidant flavonoids show therapeutic potential in the treatment of hepatitis C through inhibition of hepatitis C virus (HCV) replication. We examined the effect of treatment with the flavonols quercetin and kaempferol, the flavanone taxifolin and the flavone apigenin on HCV replication efficiency in an in vitro model. While all flavonoids studied were able to reduce viral replication at very low concentrations (ranging from 0.1 to 5 μM), quercetin appeared to be the most effective inhibitor of HCV replication, showing a marked anti-HCV activity in replicon-containing cells when combined with interferon (IFN)α. The contribution of oxidative/nitrosative stress and lipogenesis modulation to inhibition of HCV replication by quercetin was also examined. As expected, quercetin decreased HCV-induced reactive oxygen and nitrogen species (ROS/RNS) generation and lipoperoxidation in replicating cells. Quercetin also inhibited liver X receptor (LXR)α-induced lipid accumulation in LXRα-overexpressing and replicon-containing Huh7 cells. The mechanism underlying the LXRα-dependent lipogenesis modulatory effect of quercetin in HCV-replicating cells seems to involve phosphatidylinositol 3-kinase (PI3K)/AKT pathway inactivation. Thus, inhibition of the PI3K pathway by LY294002 attenuated LXRα upregulation and HCV replication mediated by lipid accumulation, showing an additive effect when combined with quercetin. Inactivation of the PI3K pathway by quercetin may contribute to the repression of LXRα-dependent lipogenesis and to the inhibition of viral replication induced by the flavonol. Combined, our data suggest that oxidative/nitrosative stress blockage and subsequent modulation of PI3K-LXRα-mediated lipogenesis might contribute to the inhibitory effect of quercetin on HCV replication.

  18. The PI3K signaling-mediated nitric oxide contributes to cardiovascular effects of angiotensin-(1-7) in the nucleus tractus solitarii of rats.

    PubMed

    Wu, Zhao-Tang; Ren, Chang-Zhen; Yang, Ya-Hong; Zhang, Ru-Wen; Sun, Jia-Cen; Wang, Yang-Kai; Su, Ding-Feng; Wang, Wei-Zhong

    2016-01-30

    Angiotensin-1-7 [Ang-(1-7)], acting via the Mas receptor in the central nervous system, is involved in the regulation of cardiovascular activity. Nitric oxide (NO) is implicated as an important modulator in the nucleus tractus solitarii (NTS), a key region involved in control of cardiovascular activity. The aim of the present study was to determine the role of phosphatidylinositol 3-kinase (PI3K) signaling in mediating the effect of Ang-(1-7) on NO generation in the NTS. In Sprague-Dawley rats, acute injection of Ang-(1-7) into the NTS significantly increased NO generation and neuronal/endothelial NO synthase (n/eNOS) activity, which were abolished by the selective Mas receptor antagonist d-Alanine-[Ang-(1-7)] (A-779), the PI3K inhibitor LY294002, or the Akt inhibitor triciribine (TCN). Western blotting analysis further demonstrated that Ang-(1-7) significantly increased levels of Akt/NOS phosphorylation in the NTS, and Ang-(1-7)-induced e/nNOS phosphorylation was antagonized by LY294002 or TCN. Furthermore, gene knockdown of PI3K by lentivirus containing small hairpin RNA in the NTS prevented the Ang-(1-7)-induced increases in NOS/Akt phosphorylation and NO production. The physiological (in vivo) experiments showed that pretreatment with the NOS inhibitor l-NAME, LY294002, or TCN abolished the decreases in blood pressure, heart rate, and renal sympathetic nerve activity induced by Ang-(1-7) injected into the NTS. Our findings suggest that nitric oxide release meditated by the Mas-PI3K-NOS signaling pathway is involved in the cardiovascular effects of Ang-(1-7) in the NTS.

  19. Cinnamaldehyde affects the biological behavior of human colorectal cancer cells and induces apoptosis via inhibition of the PI3K/Akt signaling pathway.

    PubMed

    Li, Jiepin; Teng, Yuhao; Liu, Shenlin; Wang, Zifan; Chen, Yan; Zhang, Yingying; Xi, Songyang; Xu, Song; Wang, Ruiping; Zou, Xi

    2016-03-01

    Cinnamaldehyde (CA) is a bioactive compound isolated from the stem bark of Cinnamomum cassia, that has been identified as an antiproliferative substance with pro-apoptotic effects on various cancer cell lines in vitro. In the present study, the effects of CA on human colon cancer cells were investigated at both the molecular and cellular levels. Three types of colorectal cancer cells at various stages of differentiation and invasive ability (SW480, HCT116 and LoVo) were treated with CA at final concentrations of 20, 40 and 80 µg/ml for 24 h. Compared with the control group, the proliferation inhibition rate of the human colorectal cancer cells following treatment with CA increased in a dose- and time-dependent manner. The invasion and adhesion abilities of the cells were significantly inhibited as indicated by Transwell and cell-matrix adhesion assays. Meanwhile, CA also upregulated the expression of E-cadherin and downregulated the expression of matrix metalloproteinase-2 (MMP-2) and MMP-9. CA also elevated the apoptotic rate. The levels of pro-apoptotic genes were upregulated while the levels of apoptosis inhibitory genes were decreased which further confirmed the pro-apoptotic effect of CA. In order to explore the mechanism of CA-induced apoptosis, insulin-like growth factor-1 (IGF-1) and PI3K inhibitor (LY294002) were used to regulate the phosphoinositide 3-kinase (PI3K)/AKT pathway. The transcription activity of PI3K/AKT was markedly inhibited by CA, as well as IGF-1 which functions as an anti-apoptotic factor. In conclusion, CA has the potential to be developed as a new antitumor drug. The mechanisms of action involve the regulation of expression of genes involved in apoptosis, invasion and adhesion via inhibition of the PI3K/Akt signaling pathway. PMID:26677144

  20. Dual inhibition of CDK4/Rb and PI3K/AKT/mTOR pathways by ON123300 induces synthetic lethality in mantle cell lymphomas.

    PubMed

    Divakar, S K A; Ramana Reddy, M V; Cosenza, S C; Baker, S J; Perumal, D; Antonelli, A C; Brody, J; Akula, B; Parekh, S; Reddy, E Premkumar

    2016-01-01

    This study describes the characterization of a novel kinase inhibitor, ON123300, which inhibits CDK4/6 (cyclin-dependent kinases 4 and 6) and phosphatidylinositol 3 kinase-δ (PI3K-δ) and exhibits potent activity against mantle cell lymphomas (MCLs) both in vitro and in vivo. We examined the effects of PD0332991 and ON123300 on cell cycle progression, modulation of the retinoblastoma (Rb) and PI3K/AKT pathways, and the induction of apoptosis in MCL cell lines and patient-derived samples. When Granta 519 and Z138C cells were incubated with PD0332991 and ON123300, both compounds were equally efficient in their ability to inhibit the phosphorylation of Rb family proteins. However, only ON123300 inhibited the phosphorylation of proteins associated with the PI3K/AKT pathway. Cells treated with PD0332991 rapidly accumulated in the G0/G1 phase of cell cycle as a function of increasing concentration. Although ON123300-treated cells arrested similarly at lower concentrations, higher concentrations resulted in the induction of apoptosis, which was not observed in PD0332991-treated samples. Mouse xenograft assays also showed a strong inhibition of MCL tumor growth in ON123300-treated animals. Finally, treatment of ibrutinib-sensitive and -resistant patient-derived MCLs with ON123300 also triggered apoptosis and inhibition of the Rb and PI3K/AKT pathways, suggesting that this compound might be an effective agent in MCL, including ibrutinib-resistant forms of the disease. PMID:26174628

  1. 3D-QSAR and docking studies of 3-Pyridine heterocyclic derivatives as potent PI3K/mTOR inhibitors

    NASA Astrophysics Data System (ADS)

    Yang, Wenjuan; Shu, Mao; Wang, Yuanqiang; Wang, Rui; Hu, Yong; Meng, Lingxin; Lin, Zhihua

    2013-12-01

    Phosphoinosmde-3-kinase/ mammalian target of rapamycin (PI3K/mTOR) dual inhibitors have attracted a great deal of interest as antitumor drugs research. In order to design and optimize these dual inhibitors, two types of 3D-quantitative structure-activity relationship (3D-QSAR) studies based on the ligand alignment and receptor alignment were applied using the comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA). In the study based on ligands alignment, models of PI3K (CoMFA with r2, 0.770; q2, 0.622; CoMSIA with r2, 0.945; q2, 0.748) and mTOR (CoMFA with r2, 0.850; q2, 0.654; CoMSIA with r2, 0.983; q2, 0.676) have good predictability. And in the study based on receptor alignment, models of PI3K (CoMFA with r2, 0.745; q2, 0.538; CoMSIA with r2, 0.938; q2, 0.630) and mTOR (CoMFA with r2, 0.977; q2, 0.825; CoMSIA with r2, 0.985; q2, 0.728) also have good predictability. 3D contour maps and docking results suggested different groups on the core parts of the compounds could enhance the biological activities. Finally, ten derivatives as potential candidates of PI3K/mTOR inhibitors with good predicted activities were designed.

  2. Irisin inhibits hepatic gluconeogenesis and increases glycogen synthesis via the PI3K/Akt pathway in type 2 diabetic mice and hepatocytes.

    PubMed

    Liu, Tong-Yan; Shi, Chang-Xiang; Gao, Run; Sun, Hai-Jian; Xiong, Xiao-Qing; Ding, Lei; Chen, Qi; Li, Yue-Hua; Wang, Jue-Jin; Kang, Yu-Ming; Zhu, Guo-Qing

    2015-11-01

    Increased glucose production and reduced hepatic glycogen storage contribute to metabolic abnormalities in diabetes. Irisin, a newly identified myokine, induces the browning of white adipose tissue, but its effects on gluconeogenesis and glycogenesis are unknown. In the present study, we investigated the effects and underlying mechanisms of irisin on gluconeogenesis and glycogenesis in hepatocytes with insulin resistance, and its therapeutic role in type 2 diabetic mice. Insulin resistance was induced by glucosamine (GlcN) or palmitate in human hepatocellular carcinoma (HepG2) cells and mouse primary hepatocytes. Type 2 diabetes was induced by streptozotocin/high-fat diet (STZ/HFD) in mice. In HepG2 cells, irisin ameliorated the GlcN-induced increases in glucose production, phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) expression, and glycogen synthase (GS) phosphorylation; it prevented GlcN-induced decreases in glycogen content and the phosphoinositide 3-kinase (PI3K) p110α subunit level, and the phosphorylation of Akt/protein kinase B, forkhead box transcription factor O1 (FOXO1) and glycogen synthase kinase-3 (GSK3). These effects of irisin were abolished by the inhibition of PI3K or Akt. The effects of irisin were confirmed in mouse primary hepatocytes with GlcN-induced insulin resistance and in human HepG2 cells with palmitate-induced insulin resistance. In diabetic mice, persistent subcutaneous perfusion of irisin improved the insulin sensitivity, reduced fasting blood glucose, increased GSK3 and Akt phosphorylation, glycogen content and irisin level, and suppressed GS phosphorylation and PEPCK and G6Pase expression in the liver. Irisin improves glucose homoeostasis by reducing gluconeogenesis via PI3K/Akt/FOXO1-mediated PEPCK and G6Pase down-regulation and increasing glycogenesis via PI3K/Akt/GSK3-mediated GS activation. Irisin may be regarded as a novel therapeutic strategy for insulin resistance and type 2 diabetes.

  3. Computational Analysis of the Spatiotemporal Coordination of Polarized PI3K and Rac1 Activities in Micro-Patterned Live Cells

    PubMed Central

    Chen, Chih-En; Ouyang, Mingxing; Seong, Jihye; Liao, Xiaoling; Wang, Yingxiao

    2011-01-01

    Polarized molecular activities play important roles in guiding the cell toward persistent and directional migration. In this study, the polarized distributions of the activities of phosphatidylinositol 3-kinase (PI3K) and the Rac1 small GTPase were monitored using chimeric fluorescent proteins (FPs) in cells constrained on micro-patterned strips, with one end connecting to a neighboring cell (junction end) and the other end free of cell-cell contact (free end). The recorded spatiotemporal dynamics of the fluorescent intensity from different cells was scaled into a uniform coordinate system and applied to compute the molecular activity landscapes in space and time. The results revealed different polarization patterns of PI3K and Rac1 activity induced by the growth factor stimulation. The maximal intensity of different FPs, and the edge position and velocity at the free end were further quantified to analyze their correlation and decipher the underlying signaling sequence. The results suggest that the initiation of the edge extension occurred before the activation of PI3K, which led to a stable extension of the free end followed by the Rac1 activation. Therefore, the results support a concerted coordination of sequential signaling events and edge dynamics, underscoring the important roles played by PI3K activity at the free end in regulating the stable lamellipodia extension and cell migration. Meanwhile, the quantification methods and accompanying software developed can provide a convenient and powerful computational analysis platform for the study of spatiotemporal molecular distribution and hierarchy in live cells based on fluorescence images. PMID:21738630

  4. RES-529: a PI3K/AKT/mTOR pathway inhibitor that dissociates the mTORC1 and mTORC2 complexes

    PubMed Central

    2016-01-01

    RES-529 (previously named Palomid 529, P529) is a phosphoinositide 3-kinase (PI3K)/AKT/mechanistic target of rapamycin (mTOR) pathway inhibitor that interferes with the pathway through both mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2) dissociation. This compound is currently being developed in oncology and ophthalmology. The oncology focus is for the treatment of glioblastoma, where it has received orphan designation by the US Food and Drug Administration, and prostate cancer. We present a review of the PI3K/AKT/mTOR pathway, its role in tumorigenesis, and the potential of RES-529 in cancer treatment. RES-529 inhibits mTORC1/mTORC2 activity in various cancer cell lines, as noted by decreased phosphorylation of substrates including ribosomal protein S6, 4E-BP1, and AKT, leading to cell growth inhibition and death, with activity generally in the range of 5–15 μmol/l. In animal tumor models where the PI3K/AKT/mTOR pathway is abnormally activated (i.e. glioblastoma, prostate cancer, and breast cancer), RES-529 reduces tumor growth by as much as 78%. RES-529 treatment is synergistic with radiation therapy, chemotherapy, and hormonal therapy in reducing tumor growth, potentially by preventing PI3K/AKT/mTOR pathway activation associated with these treatments. Furthermore, this compound has shown antiangiogenic activity in several animal models. mTORC1 and mTORC2 have redundant and distinct activities that contribute toward oncogenesis. Current inhibitors of this pathway have primarily targeted mTORC1, but have shown limited clinical efficacy. Inhibitors of mTORC1 and mTORC2 such as RES-529 may therefore have the potential to overcome the deficiencies found in targeting only mTORC1. PMID:26918392

  5. MiR-20a Induces Cell Radioresistance by Activating the PTEN/PI3K/Akt Signaling Pathway in Hepatocellular Carcinoma

    SciTech Connect

    Zhang, Yuqin; Zheng, Lin; Ding, Yi; Li, Qi; Wang, Rong; Liu, Tongxin; Sun, Quanquan; Yang, Hua; Peng, Shunli; Wang, Wei; Chen, Longhua

    2015-08-01

    Purpose: To investigate the role of miR-20a in hepatocellular carcinoma (HCC) cell radioresistance, which may reveal potential strategies to improve treatment. Methods and Materials: The expression of miR-20a and PTEN were detected in HCC cell lines and paired primary tissues by quantitative real-time polymerase chain reaction. Cell radiation combined with colony formation assays was administrated to discover the effect of miR-20a on radiosensitivity. Bioinformatics prediction and luciferase assay were used to identify the target of miR-20a. The phosphatidylinositol 3-kinase inhibitor LY294002 was used to inhibit phosphorylation of Akt, to verify whether miR-20a affects HCC cell radioresistance through activating the PTEN/PI3K/Akt pathway. Results: MiR-20a levels were increased in HCC cell lines and tissues, whereas PTEN was inversely correlated with it. Overexpression of miR-20a in Bel-7402 and SMMC-7721 cells enhances their resistance to the effect of ionizing radiation, and the inhibition of miR-20a in HCCLM3 and QGY-7701 cells sensitizes them to it. PTEN was identified as a direct functional target of miR-20a for the induction of radioresistance. Overexpression of miR-20a activated the PTEN/PI3K/Akt signaling pathway. Additionally, the kinase inhibitor LY294002 could reverse the effect of miR-20a–induced radioresistance. Conclusion: MiR-20a induces HCC cell radioresistance by activating the PTEN/PI3K/Akt pathway, which suggests that miR-20a/PTEN/PI3K/Akt might represent a target of investigation for developing effective therapeutic strategies against HCC.

  6. Bone marrow-derived mesenchymal stem cells enhance autophagy via PI3K/AKT signalling to reduce the severity of ischaemia/reperfusion-induced lung injury

    PubMed Central

    Li, Jing; Zhou, Jian; Zhang, Dan; Song, Yuanlin; She, Jun; Bai, Chunxue

    2015-01-01

    Autophagy, a type II programmed cell death, is essential for cell survival under stress, e.g. lung injury, and bone marrow-derived mesenchymal stem cells (BM-MSCs) have great potential for cell therapy. However, the mechanisms underlying the BM-MSC activation of autophagy to provide a therapeutic effect in ischaemia/reperfusion-induced lung injury (IRI) remain unclear. Thus, we investigate the activation of autophagy in IRI following transplantation with BM-MSCs. Seventy mice were pre-treated with BM-MSCs before they underwent lung IRI surgery in vivo. Human pulmonary micro-vascular endothelial cells (HPMVECs) were pre-conditioned with BM-MSCs by oxygen-glucose deprivation/reoxygenation (OGD) in vitro. Expression markers for autophagy and the phosphoinositide 3-kinase/protein kinase B (PI3K/Akt) signalling pathway were analysed. In IRI-treated mice, administration of BM-MSCs significantly attenuated lung injury and inflammation, and increased the level of autophagy. In OGD-treated HPMVECs, co-culture with BM-MSCs attenuated endothelial permeability by decreasing the level of cell death and enhanced autophagic activation. Moreover, administration of BM-MSCs decreased the level of PI3K class I and p-Akt while the expression of PI3K class III was increased. Finally, BM-MSCs-induced autophagic activity was prevented using the inhibitor LY294002. Administration of BM-MSCs attenuated lung injury by improving the autophagy level via the PI3K/Akt signalling pathway. These findings provide further understanding of the mechanisms related to BM-MSCs and will help to develop new cell-based therapeutic strategies in lung injury. PMID:26177266

  7. Downregulation of PI3-K/Akt/PTEN pathway and activation of mitochondrial intrinsic apoptosis by Diclofenac and Curcumin in colon cancer.

    PubMed

    Rana, Chandan; Piplani, Honit; Vaish, Vivek; Nehru, Bimla; Sanyal, S N

    2015-04-01

    Phosphatidylinositol 3-kinase (PI3-K)/PTEN/Akt signaling is over activated in various tumors including colon cancer. Activation of this pathway regulates multiple biological processes such as apoptosis, metabolism, cell proliferation, and cell growth that underlie the biology of a cancer cell. In the present study, the chemopreventive effects have been observed of Diclofenac, a preferential COX-2 inhibitory non-steroidal anti-inflammatory drugs, and Curcumin, a natural anti-inflammatory agent, in the early stage of colorectal carcinogenesis induced by 1,2-dimethylhydrazine dihydrochloride in rats. The tumor-promoting role of PI3-K/Akt/PTEN signal transduction pathway and its association with anti-apoptotic family of proteins are also observed. Both Diclofenac and Curcumin downregulated the PI3-K and Akt expression while promoting the apoptotic mechanism. Diclofenac and Curcumin administration significantly increased the expression of pro-apoptotic Bcl-2 family members (Bad and Bax) while decreasing the anti-apoptotic Bcl-2 protein. An up-regulation of cysteine protease family apoptosis executioner, such as caspase-3 and -9, is seen. Diclofenac and Curcumin inhibited the Bcl-2 protein by directly interacting at the active site by multiple hydrogen bonding, as also evident by negative glide score of Bcl-2. These drugs stimulated apoptosis by increasing reactive oxygen species (ROS) generation and simultaneously decreasing the mitochondrial membrane potential (ΔΨ M). Diclofenac and Curcumin showed anti-neoplastic effects by downregulating PI3-K/Akt/PTEN pathway, inducing apoptosis, increasing ROS generation, and decreasing ΔΨ M. The anti-neoplastic and apoptotic effects were found enhanced when both Diclofenac and Curcumin were administered together, rather than individually.

  8. Hedgehog signaling is a novel therapeutic target in tamoxifen-resistant breast cancer aberrantly activated by PI3K/AKT pathway.

    PubMed

    Ramaswamy, Bhuvaneswari; Lu, Yuanzhi; Teng, Kun-yu; Nuovo, Gerard; Li, Xiaobai; Shapiro, Charles L; Majumder, Sarmila

    2012-10-01

    Endocrine resistance is a major challenge in the management of estrogen receptor (ER)-positive breast cancers. Although multiple mechanisms leading to endocrine resistance have been proposed, the poor outcome of patients developing resistance to endocrine therapy warrants additional studies. Here we show that noncanonical Hedgehog (Hh) signaling is an alternative growth promoting mechanism that is activated in tamoxifen-resistant tumors. Importantly, phosphoinositide 3-kinase inhibitor/protein kinase B (PI3K/AKT) pathway plays a key role in regulating Hh signaling by protecting key components of this pathway from proteasomal degradation. The levels of Hh-signaling molecules SMO and GLI1 and the targets were significantly elevated in tamoxifen-resistant MCF-7 cells and T47D cells. Serial passage of the resistant cells in mice resulted in aggressive tumors that metastasized to distant organs with concurrent increases in Hh marker expression and epithelial mesenchymal transition. RNAi-mediated depletion of SMO or GLI1 in the resistant cells resulted in reduced proliferation, clonogenic survival and delayed G(1)-S transition. Notably, treatment of resistant cells with PI3K inhibitors decreased SMO and GLI1 protein levels and activity that was rescued upon blocking GSK3β and proteasomal degradation. Furthermore, treatment of tamoxifen-resistant xenografts with anti-Hh compound GDC-0449 blocked tumor growth in mice. Importantly, high GLI1 expression correlated inversely with disease-free and overall survival in a cohort of 315 patients with breast cancer. In summary, our results describe a signaling event linking PI3K/AKT pathway with Hh signaling that promotes tamoxifen resistance. Targeting Hh pathway alone or in combination with PI3K/AKT pathway could therefore be a novel therapeutic option in treating endocrine-resistant breast cancer.

  9. Cinnamaldehyde affects the biological behavior of human colorectal cancer cells and induces apoptosis via inhibition of the PI3K/Akt signaling pathway.

    PubMed

    Li, Jiepin; Teng, Yuhao; Liu, Shenlin; Wang, Zifan; Chen, Yan; Zhang, Yingying; Xi, Songyang; Xu, Song; Wang, Ruiping; Zou, Xi

    2016-03-01

    Cinnamaldehyde (CA) is a bioactive compound isolated from the stem bark of Cinnamomum cassia, that has been identified as an antiproliferative substance with pro-apoptotic effects on various cancer cell lines in vitro. In the present study, the effects of CA on human colon cancer cells were investigated at both the molecular and cellular levels. Three types of colorectal cancer cells at various stages of differentiation and invasive ability (SW480, HCT116 and LoVo) were treated with CA at final concentrations of 20, 40 and 80 µg/ml for 24 h. Compared with the control group, the proliferation inhibition rate of the human colorectal cancer cells following treatment with CA increased in a dose- and time-dependent manner. The invasion and adhesion abilities of the cells were significantly inhibited as indicated by Transwell and cell-matrix adhesion assays. Meanwhile, CA also upregulated the expression of E-cadherin and downregulated the expression of matrix metalloproteinase-2 (MMP-2) and MMP-9. CA also elevated the apoptotic rate. The levels of pro-apoptotic genes were upregulated while the levels of apoptosis inhibitory genes were decreased which further confirmed the pro-apoptotic effect of CA. In order to explore the mechanism of CA-induced apoptosis, insulin-like growth factor-1 (IGF-1) and PI3K inhibitor (LY294002) were used to regulate the phosphoinositide 3-kinase (PI3K)/AKT pathway. The transcription activity of PI3K/AKT was markedly inhibited by CA, as well as IGF-1 which functions as an anti-apoptotic factor. In conclusion, CA has the potential to be developed as a new antitumor drug. The mechanisms of action involve the regulation of expression of genes involved in apoptosis, invasion and adhesion via inhibition of the PI3K/Akt signaling pathway.

  10. Novel agents and associated toxicities of inhibitors of the pi3k/Akt/mtor pathway for the treatment of breast cancer

    PubMed Central

    Chia, S.; Gandhi, S.; Joy, A.A.; Edwards, S.; Gorr, M.; Hopkins, S.; Kondejewski, J.; Ayoub, J.P.; Califaretti, N.; Rayson, D.; Dent, S.F.

    2015-01-01

    The pi3k/Akt/mtor (phosphatidylinositol 3 kinase/ Akt/mammalian target of rapamycin) signalling pathway is an established driver of oncogenic activity in human malignancies. Therapeutic targeting of this pathway holds significant promise as a treatment strategy. Everolimus, an mtor inhibitor, is the first of this class of agents approved for the treatment of hormone receptor–positive, human epidermal growth factor receptor 2–negative advanced breast cancer. Everolimus has been associated with significant improvements in progression-free survival; however, it is also associated with increased toxicity related to its specific mechanism of action. Methods A comprehensive review of the literature conducted using a focused medline search was combined with a search of current trials at http://ClinicalTrials.gov/. Summary tables of the toxicities of the various classes of pi3k/Akt/mtor inhibitors were created. A broad group of Canadian health care professionals was assembled to review the data and to produce expert opinion and summary recommendations for possible best practices in managing the adverse events associated with these pathway inhibitors. Results Differing toxicities are associated with the various classes of pi3k/Akt/mtor pathway inhibitors. The most common unique adverse events observed in everolimus clinical trials in breast cancer include stomatitis (all grades: approximately 60%), noninfectious pneumonitis (15%), rash (40%), hyperglycemia (15%), and immunosuppression (40%). To minimize grades 3 and 4 toxicities and to attempt to attain optimal outcomes, effective management of those adverse events is critical. Management should be interdisciplinary and should use approaches that include education, early recognition, active intervention, and potentially prophylactic strategies. Discussion Everolimus likely represents the first of many complex oral targeted therapies for the treatment of breast cancer. Using this agent as a template, it is essential to

  11. Angiotensin II promotes differentiation of mouse embryonic stem cells to smooth muscle cells through PI3-kinase signaling pathway and NF-κB.

    PubMed

    Zheng, Xiaoye; Wu, Yutao; Zhu, Liangfeng; Chen, Qishan; Zhou, Yijiang; Yan, Hui; Chen, Ting; Xiao, Qingzhong; Zhu, Jianhua; Zhang, Li

    2013-01-01

    Embryonic stem cells (ES cells), the pluripotent derivatives of the inner cell mass from blastocysts, have the capacity for unlimited growth, self-renewal and differentiation toward all types of somatic cells. Angiotensin II (Ang II), the most important effector peptide of the renin-angiotensin system, is also an angiogenesis factor. However, the potential impact of Ang II on ES cell differentiation is still unknown. In the present study, we have successfully induced the differentiation of ES cells into smooth muscle cells (SMCs) on collagen IV. Interestingly, incubation of ES cells with Ang II further promoted SMC differentiation from ES cells, which was abolished by prior treatment with Ang II type 1 (AT1) receptor antagonist losartan, but not Ang II type 2 (AT2) receptor antagonist PD123319. Moreover, we found that, in parallel with SMC specific-marker induction, the expression levels of phosphoAkt and NF-Kappa B (NF-κB) p50 were up-regulated by Ang II. Importantly, addition of phosphoinositide-3 kinase (PI3K) inhibitor LY294002 led to a marked inhibition of Ang II induced SMC specific markers, phosphoAkt and NF-κB p50 expression. Furthermore, NF-κB inhibitor BAY11-7082 can inhibit Ang II induced expression of SMC specific markers. Thus, we demonstrate for the first time that Ang II plays a promotive role in the stage of ES cell differentiation to SMCs through AT1 receptor. We further confirmed that PI3K/Akt signaling pathway and NF-κB play key roles in this process.

  12. Blocking the PI3K/AKT pathway enhances mammalian reovirus replication by repressing IFN-stimulated genes

    PubMed Central

    Tian, Jin; Zhang, Xiaozhan; Wu, Hongxia; Liu, Chunguo; Li, Zhijie; Hu, Xiaoliang; Su, Shuo; Wang, Lin-Fa; Qu, Liandong

    2015-01-01

    Many host cellular signaling pathways were activated and exploited by virus infection for more efficient replication. The PI3K/Akt pathway has recently attracted considerable interest due to its role in regulating virus replication. This study demonstrated for the first time that the mammalian reovirus strains Masked Palm Civet/China/2004 (MPC/04) and Bat/China/2003 (B/03) can induce transient activation of the PI3K/Akt pathway early in infection in vitro. When UV-treated, both viruses activated PI3K/Akt signaling, indicating that the virus/receptor interaction was sufficient to activate PI3K/Akt. Reovirus virions can use both clathrin- and caveolae-mediated endocytosis, but only chlorpromazine, a specific inhibitor of clathrin-mediated endocytosis, or siRNA targeting clathrin suppressed Akt phosphorylation. We also identified the upstream molecules of the PI3K pathway. Virus infection induced phosphorylation of focal adhesion kinase (FAK) but not Gab1, and blockage of FAK phosphorylation suppressed Akt phosphorylation. Blockage of PI3K/Akt activation increased virus RNA synthesis and viral yield. We also found that reovirus infection activated the IFN-stimulated response element (ISRE) in an interferon-independent manner and up-regulated IFN-stimulated genes (ISGs) via the PI3K/Akt/EMSY pathway. Suppression of PI3K/Akt activation impaired the induction of ISRE and down-regulated the expression of ISGs. Overexpression of ISG15 and Viperin inhibited virus replication, and knockdown of either enhanced virus replication. Collectively, these results demonstrate that PI3K/Akt activated by mammalian reovirus serves as a pathway for sensing and then inhibiting virus replication/infection. PMID:26388843

  13. Heterotypic RPE-choroidal endothelial cell contact increases choroidal endothelial cell transmigration via PI 3-kinase and Rac1

    PubMed Central

    Peterson, Lynda J.; Wittchen, Erika S.; Geisen, Pete; Burridge, Keith; Hartnett, M. Elizabeth

    2008-01-01

    Age-related macular degeneration (AMD) is the major cause of non-preventable blindness. Severe forms of AMD involve breaching of the retinal pigment epithelial (RPE) barrier by underlying choroidal endothelial cells (CECs), followed by migration into, and subsequent neovascularization of the neurosensory retina. However, little is known about the interactions between RPE and CECs and the signaling events leading to CEC transmigration. While soluble chemotactic factors secreted from RPE can contribute to inappropriate CEC transmigration, other unidentified stimuli may play an additional role. Using a coculture model that maintains the natural structural orientation of CECs to the basal aspect of RPE, we show that “contact” with RPE and/or RPE extracellular matrix increases CEC transmigration of the RPE barrier. From a biochemical standpoint, contact between CECs and RPE results in an increase in the activity of the GTPase Rac1 within the CECs; this increase is dependent on upstream activation of PI 3-K and Akt1. To confirm a link between these signaling molecules and increased CEC transmigration, we performed transmigration assays while inhibiting both PI 3-K and Rac1 activity, and observed that both decreased CEC transmigration. We hypothesize that contact between CECs and RPE stimulates a signaling pathway involving PI 3-K, Akt1, and Rac1 that facilitates CEC transmigration across the RPE barrier, an important step in the development of neovascular AMD. PMID:17292356

  14. Comparison of the effects of the PI3K/mTOR inhibitors NVP-BEZ235 and GSK2126458 on tamoxifen-resistant breast cancer cells

    PubMed Central

    Kim, Ji Eun; Rewcastle, Gordon W; Finlay, Graeme J; Baguley, Bruce C

    2011-01-01

    Background Treatment with anti-estrogens or aromatase inhibitors is commonly used for patients with estrogen receptor-positive (ER+) breast cancers; however resistant disease develops almost inevitably, requiring a choice of secondary therapy. One possibility is to use inhibitors of the PI3K/mTOR pathway and several candidate drugs are in development. We examined the in vitro effects of two inhibitors of the PI3K/mTOR pathway on resistant MCF-7 cells. Results The derived sub-lines showed increased resistance to tamoxifen but none exhibited concomitantly increased sensitivity to the PI3K inhibitors. NVP-BEZ235 and GSK2126458 acted mainly by induction of cell cycle arrest, particularly in G1-phase, rather than by induction of apoptosis. The lines varied considerably in their utilization of the AKT, p70S6K and ERK pathways. NVP-BEZ235 and GSK2126458 inhibited AKT signaling but NVP-BEZ235 showed greater effects than GSK2126458 on p70S6K and rpS6 signaling with effects resembling those of rapamycin. Methods We cultured MCF-7 cells for prolonged periods either in the presence of the anti-estrogen tamoxifen (three sub-lines) or in estrogen free medium (two sub-lines) to mimic the effects of clinical treatment. We then analyzed the effects of two dual PI3K/mTOR phosphoinositide-3-kinase inhibitors, NVP-BEZ235 and GSK2126458, on the growth and signaling pathways of these MCF-7 sub-lines. The functional status of the PI3K, mTOR and ERK pathways was analyzed by measuring phosphorylation of AKT, p70S6K, rpS6 and ERK. Conclusion Increased resistance to tamoxifen in these MCF-7 sub-lines is not associated with hypersensitivity to PI3K inhibitors. While both drugs inhibited AKT signaling, NVP-BEZ235 resembled rapamycin in inhibiting the mTOR pathway. PMID:21464613

  15. Calycosin-7-O-β-d-glucoside attenuates ischemia-reperfusion injury in vivo via activation of the PI3K/Akt pathway

    PubMed Central

    REN, MIN; WANG, XUDONG; DU, GUOQING; TIAN, JIAWEI; LIU, YUJIE

    2016-01-01

    The aim of the present study was to investigate the effects and mechanisms of calycosin-7-O-β-d-glucoside (CG) on ischemia-reperfusion (I/R) injury in vivo. Hemodynamic parameters, including ejection fraction (EF), fractional shortening (FS), left ventricular end-systolic pressure (LVESP) and left ventricular end-diastolic pressure (LVEDP) were monitored using an ultrasound system, and infarct size was measured using Evans blue/tetrazolium chloride double staining. The activities of serum creatine kinase (CK), lactate dehydrogenase (LDH) and superoxide dismutase (SOD), and the levels of malondialdehyde (MDA) were determined to assess the degree of myocardial injury and oxidative stress-induced damage. The protein expression levels of cleaved-caspase-3, cleaved-caspase-9, phosphorylated (p)-phosphatidylinositol 3-kinase (PI3K) p85, PI3K p85, p-Akt and Akt were determined using western blotting. The results demonstrated that pretreatment with high dose (H)-CG markedly improved cardiac function, as evidenced by upregulated EF, FS and LVESP, and downregulated LVEDP. In addition, administration of CG resulted in significant decreases in infarct size in the I/R+low dose-CG and I/R+H-CG groups, compared with the I/R group. The activities of CK and LDH, and the levels of MDA in the I/R+H-CG group were reduced, compared with those in the I/R group, whereas SOD activity was elevated. Treatment with CG inhibited the cleavage and activity of caspase-3 and caspase-9, and enhanced the phosphorylation of PI3K p85 and Akt. Notably, administration of the PI3K inhibitor, LY294002, markedly lowered the levels of p-PI3K p85/p-Akt, and eradicated the inhibitory effects of H-CG on infarct size, myocardial injury and oxidative stress-induced damage. Taken together, the results suggested that CG may alleviate I/R injury by activating the PI3K/Akt signaling pathway. PMID:26648122

  16. Combination of verteporfin-PDT and PI3K inhibitors enhances cell growth inhibition and apoptosis in endothelial cells

    NASA Astrophysics Data System (ADS)

    Kraus, Daniel; Chen, Bin

    2016-03-01

    Vascular targeted photodynamic therapy is a promising cancer treatment modality by ablating tumor vasculature. The effectiveness of this treatment is often compromised by regrowth of endothelial cells, which causes tumor recurrence. In this preliminary report, we showed that activated PI3K signaling was involved in endothelial cell regrowth after PDT with verteporfin and combination between verteporfin-PDT and PI3K pathway inhibitor BEZ235 induced more cell apoptosis and greater inhibition in cell proliferation. These results suggest that rational combination of verteporfin-PDT and PI3K inhibitors result in enhanced treatment outcomes.

  17. Monosodium urate activates Src/Pyk2/PI3 kinase and cathepsin dependent unconventional protein secretion from human primary macrophages.

    PubMed

    Välimäki, Elina; Miettinen, Juho J; Lietzén, Niina; Matikainen, Sampsa; Nyman, Tuula A

    2013-03-01

    Monosodium urate (MSU) is an endogenous danger signal that is crystallized from uric acid released from injured cells. MSU is known to activate inflammatory response in macrophages but the molecular mechanisms involved have remained uncharacterized. Activated macrophages start to secrete proteins to activate immune response and to recruit other immune cells to the site of infection and/or tissue damage. Secretome characterization after activation of innate immune system is essential to unravel the details of early phases of defense responses. Here, we have analyzed the secretome of human primary macrophages stimulated with MSU using quantitative two-dimensional gel electrophoresis based proteomics as well as high-throughput qualitative GeLC-MS/MS approach combining protein separation by SDS-PAGE and protein identification by liquid chromatography-MS/MS. Both methods showed that MSU stimulation induced robust protein secretion from lipopolysaccharide-primed human macrophages. Bioinformatic analysis of the secretome data showed that MSU stimulation strongly activates unconventional, vesicle mediated protein secretion. The unconventionally secreted proteins included pro-inflammatory cytokines like IL-1β and IL-18, interferon-induced proteins, and danger signal proteins. Also active forms of lysosomal proteases cathepsins were secreted on MSU stimulation, and cathepsin activity was essential for MSU-induced unconventional protein secretion. Additionally, proteins associated to phosphorylation events including Src family tyrosine kinases were increased in the secretome of MSU-stimulated cells. Our functional studies demonstrated that Src, Pyk2, and PI3 kinases act upstream of cathepsins to activate the overall protein secretion from macrophages. In conclusion, we provide the first comprehensive characterization of protein secretion pathways activated by MSU in human macrophages, and reveal a novel role for cathepsins and Src, Pyk2, PI3 kinases in the activation of

  18. Metabolic Reprogramming by the PI3K-Akt-mTOR Pathway in Cancer.

    PubMed

    Lien, Evan C; Lyssiotis, Costas A; Cantley, Lewis C

    2016-01-01

    In the past decade, there has been a resurgence of interest in elucidating how metabolism is altered in cancer cells and how such dependencies can be targeted for therapeutic gain. At the core of this research is the concept that metabolic pathways are reprogrammed in cancer cells to divert nutrients toward anabolic processes to facilitate enhanced growth and proliferation. Importantly, physiological cellular signaling mechanisms normally tightly regulate the ability of cells to gain access to and utilize nutrients, posing a fundamental barrier to transformation. This barrier is often overcome by aberrations in cellular signaling that drive tumor pathogenesis by enabling cancer cells to make critical cellular decisions in a cell-autonomous manner. One of the most frequently altered pathways in human cancer is the PI3K-Akt-mTOR signaling pathway. Here, we describe mechanisms by which this signaling network is responsible for controlling cellular metabolism. Through both the post-translational regulation and the induction of transcriptional programs, the PI3K-Akt-mTOR pathway coordinates the uptake and utilization of multiple nutrients, including glucose, glutamine, nucleotides, and lipids, in a manner best suited for supporting the enhanced growth and proliferation of cancer cells. These regulatory mechanisms illustrate how metabolic changes in cancer are closely intertwined with oncogenic signaling pathways that drive tumor initiation and progression. PMID:27557534

  19. PI3K signaling of autophagy is required for starvation tolerance and virulenceof Cryptococcus neoformans

    PubMed Central

    Hu, Guowu; Hacham, Moshe; Waterman, Scott R.; Panepinto, John; Shin, Soowan; Liu, Xiaoguang; Gibbons, Jack; Valyi-Nagy, Tibor; Obara, Keisuke; Jaffe, H. Ari; Ohsumi, Yoshinori; Williamson, Peter R.

    2008-01-01

    Autophagy is a process by which cells recycle cytoplasm and defective organelles during stress situations such as nutrient starvation. It can also be used by host cells as an immune defense mechanism to eliminate infectious pathogens. Here we describe the use of autophagy as a survival mechanism and virulence-associated trait by the human fungal pathogen Cryptococcus neoformans. We report that a mutant form of C. neoformans lacking the Vps34 PI3K (vps34Δ), which is known to be involved in autophagy in ascomycete yeast, was defective in the formation of autophagy-related 8–labeled (Atg8-labeled) vesicles and showed a dramatic attenuation in virulence in mouse models of infection. In addition, autophagic vesicles were observed in WT but not vps34Δ cells after phagocytosis by a murine macrophage cell line, and Atg8 expression was exhibited in WT C. neoformans during human infection of brain. To dissect the contribution of defective autophagy in vps34Δ C. neoformans during pathogenesis, a strain of C. neoformans in which Atg8 expression was knocked down by RNA interference was constructed and these fungi also demonstrated markedly attenuated virulence in a mouse model of infection. These results demonstrated PI3K signaling and autophagy as a virulence-associated trait and survival mechanism during infection with a fungal pathogen. Moreover, the data show that molecular dissection of such pathogen stress-response pathways may identify new approaches for chemotherapeutic interventions. PMID:18259613

  20. Computational Modeling of PI3K/AKT and MAPK Signaling Pathways in Melanoma Cancer

    PubMed Central

    Pappalardo, Francesco; Russo, Giulia; Candido, Saverio; Pennisi, Marzio; Cavalieri, Salvatore; Motta, Santo; McCubrey, James A.; Nicoletti, Ferdinando; Libra, Massimo

    2016-01-01

    Background Malignant melanoma is an aggressive tumor of the skin and seems to be resistant to current therapeutic approaches. Melanocytic transformation is thought to occur by sequential accumulation of genetic and molecular alterations able to activate the Ras/Raf/MEK/ERK (MAPK) and/or the PI3K/AKT (AKT) signalling pathways. Specifically, mutations of B-RAF activate MAPK pathway resulting in cell cycle progression and apoptosis prevention. According to these findings, MAPK and AKT pathways may represent promising therapeutic targets for an otherwise devastating disease. Result Here we show a computational model able to simulate the main biochemical and metabolic interactions in the PI3K/AKT and MAPK pathways potentially involved in melanoma development. Overall, this computational approach may accelerate the drug discovery process and encourages the identification of novel pathway activators with consequent development of novel antioncogenic compounds to overcome tumor cell resistance to conventional therapeutic agents. The source code of the various versions of the model are available as S1 Archive. PMID:27015094

  1. Flavonoids Extraction from Propolis Attenuates Pathological Cardiac Hypertrophy through PI3K/AKT Signaling Pathway

    PubMed Central

    Sun, Guang-wei; Qiu, Zhi-dong; Wang, Wei-nan; Sui, Xin

    2016-01-01

    Propolis, a traditional medicine, has been widely used for a thousand years as an anti-inflammatory and antioxidant drug. The flavonoid fraction is the main active component of propolis, which possesses a wide range of biological activities, including activities related to heart disease. However, the role of the flavonoids extraction from propolis (FP) in heart disease remains unknown. This study shows that FP could attenuate ISO-induced pathological cardiac hypertrophy (PCH) and heart failure in mice. The effect of the two fetal cardiac genes, atrial natriuretic factor (ANF) and β-myosin heavy chain (β-MHC), on PCH was reversed by FP. Echocardiography analysis revealed cardiac ventricular dilation and contractile dysfunction in ISO-treated mice. This finding is consistent with the increased heart weight and cardiac ANF protein levels, massive replacement fibrosis, and myocardial apoptosis. However, pretreatment of mice with FP could attenuate cardiac dysfunction and hypertrophy in vivo. Furthermore, the cardiac protection of FP was suppressed by the pan-PI3K inhibitor wortmannin. FP is a novel cardioprotective agent that can attenuate adverse cardiac dysfunction, hypertrophy, and associated disorder, such as fibrosis. The effects may be closely correlated with PI3K/AKT signaling. FP may be clinically used to inhibit PCH progression and heart failure. PMID:27213000

  2. Potential Molecular Targeted Therapeutics: Role of PI3-K/Akt/mTOR Inhibition in Cancer.

    PubMed

    Sokolowski, Kevin M; Koprowski, Steven; Kunnimalaiyaan, Selvi; Balamurugan, Mariappan; Gamblin, T Clark; Kunnimalaiyaan, Muthusamy

    2016-01-01

    Primary liver cancer is one of the most commonly occurring cancers worldwide. Hepatocellular carcinoma (HCC) represents the majority of primary liver cancer and is the 3rd most common cause of cancer-related deaths globally. Survival rates of patients with HCC are dependent upon early detection as concomitant liver dysfunction and advanced disease limits traditional therapeutic options such as resection or ablation. Unfortunately, at the time of diagnosis, most patients are not eligible for curative surgery and have a five-year relative survival rate less than 20%, leading to systemic therapy as the only option. Currently, sorafenib is the only approved systemic therapy; however, it has a limited survival advantage and low efficacy prompting alternative strategies. The inception of sorafenib for HCC systemic therapy and the understanding involved of cancer therapy have led to an enhanced focus of the PI3-k/Akt/mTOR pathway as a potential area of targeting including pan and isoform-specific PI3-K inhibitors, Akt blockade, and mTOR suppression. The multitude, expanding roles, and varying clinical trials of these inhibitors have led to an increase in knowledge and availability for current and future studies. In this review, we provide a review of the literature with the aim to focus on potential targets for HCC therapies as well as an in depth focus on Akt inhibition.

  3. The Rho Guanine Nucleotide Exchange Factor DRhoGEF2 Is a Genetic Modifier of the PI3K Pathway in Drosophila.

    PubMed

    Chang, Ying-Ju; Zhou, Lily; Binari, Richard; Manoukian, Armen; Mak, Tak; McNeill, Helen; Stambolic, Vuk

    2016-01-01

    The insulin/IGF-1 signaling pathway mediates various physiological processes associated with human health. Components of this pathway are highly conserved throughout eukaryotic evolution. In Drosophila, the PTEN ortholog and its mammalian counterpart downregulate insulin/IGF signaling by antagonizing the PI3-kinase function. From a dominant loss-of-function genetic screen, we discovered that mutations of a Dbl-family member, the guanine nucleotide exchange factor DRhoGEF2 (DRhoGEF22(l)04291), suppressed the PTEN-overexpression eye phenotype. dAkt/dPKB phosphorylation, a measure of PI3K signaling pathway activation, increased in the eye discs from the heterozygous DRhoGEF2 wandering third instar larvae. Overexpression of DRhoGEF2, and it's functional mammalian ortholog PDZ-RhoGEF (ArhGEF11), at various stages of eye development, resulted in both dPKB/Akt-dependent and -independent phenotypes, reflecting the complexity in the crosstalk between PI3K and Rho signaling in Drosophila.

  4. The Rho Guanine Nucleotide Exchange Factor DRhoGEF2 Is a Genetic Modifier of the PI3K Pathway in Drosophila

    PubMed Central

    Chang, Ying-Ju; Zhou, Lily; Binari, Richard; Manoukian, Armen; Mak, Tak; McNeill, Helen; Stambolic, Vuk

    2016-01-01

    The insulin/IGF-1 signaling pathway mediates various physiological processes associated with human health. Components of this pathway are highly conserved throughout eukaryotic evolution. In Drosophila, the PTEN ortholog and its mammalian counterpart downregulate insulin/IGF signaling by antagonizing the PI3-kinase function. From a dominant loss-of-function genetic screen, we discovered that mutations of a Dbl-family member, the guanine nucleotide exchange factor DRhoGEF2 (DRhoGEF22(l)04291), suppressed the PTEN-overexpression eye phenotype. dAkt/dPKB phosphorylation, a measure of PI3K signaling pathway activation, increased in the eye discs from the heterozygous DRhoGEF2 wandering third instar larvae. Overexpression of DRhoGEF2, and it’s functional mammalian ortholog PDZ-RhoGEF (ArhGEF11), at various stages of eye development, resulted in both dPKB/Akt-dependent and -independent phenotypes, reflecting the complexity in the crosstalk between PI3K and Rho signaling in Drosophila. PMID:27015411

  5. The Rho Guanine Nucleotide Exchange Factor DRhoGEF2 Is a Genetic Modifier of the PI3K Pathway in Drosophila.

    PubMed

    Chang, Ying-Ju; Zhou, Lily; Binari, Richard; Manoukian, Armen; Mak, Tak; McNeill, Helen; Stambolic, Vuk

    2016-01-01

    The insulin/IGF-1 signaling pathway mediates various physiological processes associated with human health. Components of this pathway are highly conserved throughout eukaryotic evolution. In Drosophila, the PTEN ortholog and its mammalian counterpart downregulate insulin/IGF signaling by antagonizing the PI3-kinase function. From a dominant loss-of-function genetic screen, we discovered that mutations of a Dbl-family member, the guanine nucleotide exchange factor DRhoGEF2 (DRhoGEF22(l)04291), suppressed the PTEN-overexpression eye phenotype. dAkt/dPKB phosphorylation, a measure of PI3K signaling pathway activation, increased in the eye discs from the heterozygous DRhoGEF2 wandering third instar larvae. Overexpression of DRhoGEF2, and it's functional mammalian ortholog PDZ-RhoGEF (ArhGEF11), at various stages of eye development, resulted in both dPKB/Akt-dependent and -independent phenotypes, reflecting the complexity in the crosstalk between PI3K and Rho signaling in Drosophila. PMID:27015411

  6. Hypoglycemic effect of D-chiro-inositol in type 2 diabetes mellitus rats through the PI3K/Akt signaling pathway.

    PubMed

    Gao, Yun-Feng; Zhang, Meng-Na; Wang, Tian-Xin; Wu, Tian-Chen; Ai, Ru-Dan; Zhang, Ze-Sheng

    2016-09-15

    In this investigation, a model of type 2 diabetes mellitus (T2DM) was used on Sprague-Dawley (SD) rats to clarify more details of the mechanism in the therapy of T2DM. D-chiro-inositol (DCI) was administrated to the diabetic rats as two doses [30, 60 mg/(kg·body weight·day)]. The biochemical indices revealed that DCI had a positive effect on hypoglycemic activity and promoted the glycogen synthesis. The rats in DCI high-dosage group had a blood glucose reduction rate of 21.5% after 5 weeks of treatment, and had insulin content in serum about 15.3 ± 2.37 mIU/L which was significantly decreased than diabetes control group. Real-time polymerase chain reaction (RT-PCR) results revealed that DCI gave a positive regulation on glycogen synthase (GS) and protein glucose transporter-4 (Glut4). Western blotting suggested that DCI could up-regulated the expression of the phosphatidylinositol-3-kinase (PI3K) p85, PI3Kp110, GS as well as the phosphorylation of protein kinase B (Akt) both in the liver and the skeletal muscle. The results also revealed that DCI enhanced the Glut4 expression on skeletal muscle. Above all, DCI played a positive role in regulating insulin-mediated glucose uptake through the PI3K/Akt signaling pathway in T2DM rats.

  7. Norepinephrine and endothelin activate diacylglycerol kinases in caveolae/rafts of rat mesenteric arteries: agonist-specific role of PI3-kinase.

    PubMed

    Clarke, Christopher J; Ohanian, Vasken; Ohanian, Jacqueline

    2007-05-01

    The phosphatidylinositol (PI) signaling pathway mediates norepinephrine (NE)- and endothelin-1 (ET-1)-stimulated vascular smooth muscle contraction through an inositol-trisphosphate-induced rise in intracellular calcium and diacylglycerol (DG) activation of protein kinase C (PKC). Subsequent activation of DG kinases (DGKs) metabolizes DG to phosphatidic acid (PA), potentially regulating PKC activity. Because precise regulation and spatial restriction of the PI pathway is necessary for specificity, we have investigated whether this occurs within caveolae/rafts, specialized plasma membrane microdomains implicated in vascular smooth muscle contraction. We show that components of the PI signaling cascade-phosphatidylinositol 4,5-bisphosphate (PIP(2)), PA, and DGK-theta are present in caveolae/rafts prepared from rat mesenteric small arteries. Stimulation with NE or ET-1 induced [(33)P]PIP(2) hydrolysis solely within caveolae/rafts. NE stimulated an increase in DGK activity in caveolae/rafts alone, whereas ET-1 activated DGK in caveolae/rafts and noncaveolae/rafts; however, [(33)P]PA increased in all fractions with both agonists. Previously, we reported that NE activated DGK-theta in a phosphatidylinositol 3-kinase (PI3-kinase)-dependent manner; here, we describe PI3-kinase-dependent DGK activation and [(33)P]PA production in caveolae/rafts in response to NE but not ET-1. Additionally, PKB, a potential activator of DGK-theta, translocated to caveolae/rafts in response to NE but not ET-1, and PI3-kinase inhibition prevented this. Furthermore, PI3-kinase inhibition reduced the sensitivity of contraction to NE but not ET-1. Our study shows that caveolae/rafts are major sites of vasoconstrictor hormone activation of the PI pathway in intact small arteries and suggest a link between lipid signaling events within caveolae/rafts and contraction. PMID:17208990

  8. EMBRYONIC TESTIS CORD FORMATION AND MESONEPHRIC CELL MIGRATION REQUIRES THE PHOSPHOTIDYLINOSITOL 3-KINASE (PI3K) SIGNALING PATHWAY. (R827405)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  9. Recent Syntheses of PI3K/Akt/mTOR Signaling Pathway Inhibitors

    PubMed Central

    2013-01-01

    This review focuses on the syntheses of PI3K/Akt/mTOR inhibitors that have been reported outside of the patent literature in the last 5 years but is largely centered on synthetic work reported in 2011 and 2012. While focused on syntheses of inhibitors, some information on in vitro and in vivo testing of compounds is also included. Many of these reported compounds are reversible, competitive adenosine triphosphate (ATP) binding inhibitors, so given the structural similarities of many of these compounds to the adenine core, this review presents recent work on inhibitors based on where the synthetic chemistry was started, i.e. inhibitor syntheses which started with purines/pyrimidines are followed by inhibitor syntheses which began with pyridines, pyrazines, azoles, and triazines then moves to inhibitors which bear no structural resemblance to adenine: liphagal, wortmannin and quercetin analogs. The review then finishes with a short section on recent syntheses of phosphotidyl inositol (PI) analogs since competitive PI binding inhibitors represent an alternative to the competitive ATP binding inhibitors which have received the most attention. PMID:23735831

  10. PI3K-delta mediates double-stranded RNA-induced upregulation of B7-H1 in BEAS-2B airway epithelial cells

    SciTech Connect

    Kan-o, Keiko; Matsumoto, Koichiro; Asai-Tajiri, Yukari; Fukuyama, Satoru; Hamano, Saaka; Seki, Nanae; Nakanishi, Yoichi; Inoue, Hiromasa

    2013-05-31

    Highlights: •Double-stranded RNA upregulates B7-H1 on BEAS-2B airway epithelial cells. •The upregulation of B7-H1 is attenuated by inhibition of PI3Kδ isoform. •PI3Kδ-mediated upregulation of B7-H1 is independent of NF-κB activation. •Inhibition of PI3Kδ may prevent persistent viral infection induced by B7-H1. -- Abstract: Airway viral infection disturbs the health-related quality of life. B7-H1 (also known as PD-L1) is a coinhibitory molecule associated with the escape of viruses from the mucosal immunity, leading to persistent infection. Most respiratory viruses generate double-stranded (ds) RNA during replication. The stimulation of cultured airway epithelial cells with an analog of viral dsRNA, polyinosinic-polycytidylic acid (poly IC) upregulates the expression of B7-H1 via activation of the nuclear factor κB(NF-κB). The mechanism of upregulation was investigated in association with phosphatidylinositol 3-kinases (PI3Ks). Poly IC-induced upregulation of B7-H1 was profoundly suppressed by a pan-PI3K inhibitor and partially by an inhibitor or a small interfering (si)RNA for PI3Kδ in BEAS-2B cells. Similar results were observed in the respiratory syncytial virus-infected cells. The expression of p110δ was detected by Western blot and suppressed by pretreatment with PI3Kδ siRNA. The activation of PI3Kδ is typically induced by oxidative stress. The generation of reactive oxygen species was increased by poly IC. Poly IC-induced upregulation of B7-H1 was attenuated by N-acetyl-L-cysteine, an antioxidant, or by oxypurinol, an inhibitor of xanthine oxidase. Poly IC-induced activation of NF-κB was suppressed by a pan-PI3K inhibitor but not by a PI3Kδ inhibitor. These results suggest that PI3Kδ mediates dsRNA-induced upregulation of B7-H1 without affecting the activation of NF-κB.

  11. Vesicular trafficking and stress response coupled to PI3K inhibition by LY294002 as revealed by proteomic and cell biological analysis

    PubMed Central

    Takáč, Tomáš; Pechan, Tibor; Šamajová, Olga; Šamaj, Jozef

    2013-01-01

    LY294002 is a synthetic quercetin-like compound which, unlike wortmannin, is an inhibitor of phosphatidylinositol 3-kinase (PI3K). It inhibits endocytosis and vacuolar transport. We report here on the proteome-wide effects of LY294002 on Arabidopsis roots focusing on proteins involved in vesicular trafficking and stress response. At the subcellular level, LY294002 caused swelling and clustering of late endosomes leading to inhibition of vacuolar transport. At the proteome level, this compound caused changes in abundances of proteins categorized to 10 functional classes. Among proteins involved in vesicular trafficking, a small GTPase ARFA1f was more abundant, indicating its possible contribution to the aggregation and fusion of late endosomes triggered by LY294002. Our study provides new information on storage proteins and vacuolar hydrolases in vegetative tissues treated by LY294002. Vacuolar hydrolases were downregulated while storage proteins were more abundant, suggesting that storage proteins were protected from degradation in swollen multivesicular bodies upon LY294002 treatment. Upregulation of 2S albumin was validated by immunoblotting and immunolabelling analyses. Our study also pointed to the control of antioxidant enzyme machinery by PI3K because LY294002 downregulated two isozymes of superoxide dismutase. This most likely occurred via PI3K–mediated downregulation of protein AtDJ1A. Finally, we discuss specificity differences of LY294002 and wortmannin against PI3K which are reflected at the proteome level. Compared to wortmannin, LY294002 showed more narrow and perhaps also more specific effects on proteins as suggested by gene ontology functional annotation. PMID:23931732

  12. Inhibition of PI3K-Akt Signaling Blocks Exercise-Mediated Enhancement of Adult Neurogenesis and Synaptic Plasticity in the Dentate Gyrus

    PubMed Central

    Bruel-Jungerman, Elodie; Veyrac, Alexandra; Dufour, Franck; Horwood, Jennifer; Laroche, Serge; Davis, Sabrina

    2009-01-01

    Background Physical exercise has been shown to increase adult neurogenesis in the dentate gyrus and enhances synaptic plasticity. The antiapoptotic kinase, Akt has also been shown to be phosphorylated following voluntary exercise; however, it remains unknown whether the PI3K-Akt signaling pathway is involved in exercise-induced neurogenesis and the associated facilitation of synaptic plasticity in the dentate gyrus. Methodology/Principal Findings To gain insight into the potential role of this signaling pathway in exercise-induced neurogenesis and LTP in the dentate gyrus rats were infused with the PI3K inhibitor, LY294002 or vehicle control solution (icv) via osmotic minipumps and exercised in a running wheel for 10 days. Newborn cells in the dentate gyrus were date-labelled with BrdU on the last 3 days of exercise. Then, they were either returned to the home cage for 2 weeks to assess exercise-induced LTP and neurogenesis in the dentate gyrus, or were killed on the last day of exercise to assess proliferation and activation of the PI3K-Akt cascade using western blotting. Conclusions/Significance Exercise increases cell proliferation and promotes survival of adult-born neurons in the dentate gyrus. Immediately after exercise, we found that Akt and three downstream targets, BAD, GSK3β and FOXO1 were activated. LY294002 blocked exercise-induced phosphorylation of Akt and downstream target proteins. This had no effect on exercise-induced cell proliferation, but it abolished most of the beneficial effect of exercise on the survival of newly generated dentate gyrus neurons and prevented exercise-induced increase in dentate gyrus LTP. These results suggest that activation of the PI3 kinase-Akt signaling pathway plays a significant role via an antiapoptotic function in promoting survival of newly formed granule cells generated during exercise and the associated increase in synaptic plasticity in the dentate gyrus. PMID:19936256

  13. Insulin and IGFs enhance hepatocyte differentiation from human embryonic stem cells via the PI3K/AKT pathway.

    PubMed

    Magner, Nataly L; Jung, Yunjoon; Wu, Jian; Nolta, Jan A; Zern, Mark A; Zhou, Ping

    2013-10-01

    Human embryonic stem cells (hESCs) can be progressively differentiated into definitive endoderm (DE), hepatic progenitors, and hepatocytes, and thus provide an excellent model system for the mechanistic study of hepatocyte differentiation, which is currently poorly understood. Here, we found that insulin enhanced hepatocyte differentiation from hESC-derived DE. Insulin activated the PI3K/AKT pathway, but not the mitogen-activated protein kinase pathway in the DE cells, and inhibition of the PI3K/AKT pathways by inhibitors markedly inhibited hepatocyte differentiation. In addition, insulin-like growth factor 1 (IGF1) and IGF2 also activated the PI3K/AKT pathway in DE cells and their expression was robustly upregulated during hepatocyte differentiation from DE. Furthermore, inhibition of IGF receptor 1 (IGF1R) by a small molecule inhibitor PPP or knockdown of the IGF1R by shRNA attenuated hepatocyte differentiation. Moreover, simultaneous knockdown of the IGF1R and the insulin receptor with shRNAs markedly reduced the activation of AKT and substantially impaired hepatocyte differentiation. The PI3K pathway specifically enhanced the expression of HNF1 and HNF4 to regulate hepatocyte differentiation from DE. Although inhibition of the PI3K pathway was previously shown to be required for the induction of DE from hESCs, our study revealed a positive role of the PI3K pathway in hepatocyte differentiation after the DE stage, and has advanced our understanding of hepatocyte cell fate determination.

  14. PI3K/Akt1 signalling specifies foregut precursors by generating regionalized extra-cellular matrix

    PubMed Central

    Villegas, S Nahuel; Rothová, Michaela; Barrios-Llerena, Martin E; Pulina, Maria; Hadjantonakis, Anna-Katerina; Le Bihan, Thierry; Astrof, Sophie; Brickman, Joshua M

    2013-01-01

    During embryonic development signalling pathways act repeatedly in different contexts to pattern the emerging germ layers. Understanding how these different responses are regulated is a central question for developmental biology. In this study, we used mouse embryonic stem cell (mESC) differentiation to uncover a new mechanism for PI3K signalling that is required for endoderm specification. We found that PI3K signalling promotes the transition from naïve endoderm precursors into committed anterior endoderm. PI3K promoted commitment via an atypical activity that delimited epithelial-to-mesenchymal transition (EMT). Akt1 transduced this activity via modifications to the extracellular matrix (ECM) and appropriate ECM could itself induce anterior endodermal identity in the absence of PI3K signalling. PI3K/Akt1-modified ECM contained low levels of Fibronectin (Fn1) and we found that Fn1 dose was key to specifying anterior endodermal identity in vivo and in vitro. Thus, localized PI3K activity affects ECM composition and ECM in turn patterns the endoderm. DOI: http://dx.doi.org/10.7554/eLife.00806.001 PMID:24368729

  15. Activation of PI3K/Akt pathway limits JNK-mediated apoptosis during EV71 infection.

    PubMed

    Zhang, Hua; Li, Fengqi; Pan, Ziye; Wu, Zhijun; Wang, Yanhong; Cui, Yudong

    2014-11-01

    Apoptosis is frequently induced to inhibit virus replication during infection of Enterovirus 71 (EV71). On the contrary, anti-apoptotic pathway, such as PI3K/Akt pathway, is simultaneously exploited by EV71 to accomplish the viral life cycle. The relationship by which EV71-induced apoptosis and PI3K/Akt signaling pathway remains to be elucidated. In this study, we demonstrated that EV71 infection altered Bax conformation and triggered its redistribution from the cytosol to mitochondria in RD cells. Subsequently, cytochrome c was released from mitochondria to cytosol. We also found that c-Jun NH2-terminal kinase (JNK) was activated during EV71 infection. The JNK specific inhibitor significantly inhibited Bax activation and cytochrome c release, suggesting that EV71-induced apoptosis was involved into a JNK-dependent manner. Meanwhile, EV71-induced Akt phosphorylation involved a PI3K-dependent mechanism. Inhibition of the PI3K/Akt pathway enhanced JNK phosphorylation and the JNK-mediated apoptosis upon EV71 infection. Moreover, PI3K/Akt pathway phosphorylated apoptosis signal-regulating kinase 1 (ASK1) and negatively regulated the ASK1 activity. Knockdown of ASK1 significantly decreased JNK phosphorylation, which implied that ASK1 phosphorylation by Akt inhibited ASK1-mediated JNK activation. Collectively, these data reveal that activation of the PI3K/Akt pathway limits JNK-mediated apoptosis by phosphorylating and inactivating ASK1 during EV71 infection.

  16. The immune receptor Tim-3 mediates activation of PI3 kinase/mTOR and HIF-1 pathways in human myeloid leukaemia cells.

    PubMed

    Prokhorov, Alexandr; Gibbs, Bernhard F; Bardelli, Marco; Rüegg, Laura; Fasler-Kan, Elizaveta; Varani, Luca; Sumbayev, Vadim V

    2015-02-01

    The T-cell immunoglobulin and mucin domain 3 (Tim-3) is a plasma membrane-associated protein that is highly expressed in human acute myeloid leukaemia cells. As an acute myeloid leukaemia antigen, it could therefore be considered as a potential target for immune therapy and highly-specific drug delivery. However, a conceptual understanding of its biological role is required before consideration of this protein for therapeutic settings. Here, we reveal the detailed mechanism of action underlying the biological responses mediated by the Tim-3 receptor in myeloid cells. Our studies demonstrate that Tim-3 triggers growth factor type responses in acute myeloid leukaemia cells by activating a phosphatidylinositol-3 kinase (PI-3K)/mammalian target of rapamycin (mTOR) pathway. In addition, the receptor activates hypoxic signalling pathways upregulating glycolysis and pro-angiogenic responses. These findings suggest that Tim-3 could be used as a potential therapeutic target for immune therapy and drug delivery in human acute myeloid leukaemia cells.

  17. A novel PI3K inhibitor PIK-C98 displays potent preclinical activity against multiple myeloma

    PubMed Central

    Yu, Yang; Qi, Huixin; Han, Kunkun; Tang, Juan; Zhang, Zubin; Zeng, Yuanying; Cao, Biyin; Qiao, Chunhua; Zhang, Hongjian; Hou, Tingjun; Mao, Xinliang

    2015-01-01

    Recent clinical trials have demonstrated targeting PI3K pathway is a promising strategy for the treatment of blood cancers. To identify novel PI3K inhibitors, we performed a high throughput virtual screen and identified several novel small molecule compounds, including PIK-C98 (C98). The cell-free enzymatic studies showed that C98 inhibited all class I PI3Ks at nano- or low micromolar concentrations but had no effects on AKT or mTOR activity. Molecular docking analysis revealed that C98 interfered with the ATP-binding pockets of PI3Ks by forming H-bonds and arene-H interactions with specific amino acid residues. The cellular assays demonstrated that C98 specifically inhibited PI3K/AKT/mTOR signaling pathway, but had no effects on other kinases and proteins including IGF-1R, ERK, p38, c-Src, PTEN, and STAT3. Inhibition of PI3K by C98 led to myeloma cell apoptosis. Furthermore, oral administration of C98 delayed tumor growth in two independent human myeloma xenograft models in nude mice but did not show overt toxicity. Pharmacokinetic analyses showed that C98 was well penetrated into myeloma tumors. Therefore, through a high throughput virtual screen we identified a novel PI3K inhibitor that is orally active against multiple myeloma with great potential for further development. PMID:25474140

  18. Presence of both alterations in FGFR/FGF and PI3K/AKT/mTOR confer improved outcomes for patients with metastatic breast cancer treated with PI3K/AKT/mTOR inhibitors

    PubMed Central

    Wheler, Jennifer J.; Atkins, Johnique T.; Janku, Filip; Moulder, Stacy L.; Stephens, Philip J.; Yelensky, Roman; Valero, Vicente; Miller, Vincent; Kurzrock, Razelle; Meric-Bernstam, Funda

    2016-01-01

    There is limited data on co-expression of FGFR/FGR amplifications and PI3K/ AKT/mTOR alterations in breast cancer. Tumors from patients with metastatic breast cancer referred to our Phase I Program were analyzed by next generation sequencing (NGS). Genomic libraries were selected for all exons of 236 (or 182) cancer-related genes sequenced to average depth of >500× in a CLIA laboratory (Foundation Medicine, Cambridge, MA, USA) and analyzed for all classes of genomic alterations. We report genomic profiles of 112 patients with metastatic breast cancer, median age 55 years (range, 27-78). Twenty-four patients (21%) had at least one amplified FGFR or FGF. Fifteen of the 24 patients (63%) also had an alteration in the PI3K/ AKT/mTOR pathway. There was no association between alterations in FGFR/FGF and PI3K/AKT/mTOR (P=0.49). Patients with simultaneous amplification in FGFR/FGF signaling and the PI3K/AKT/mTOR pathway had a higher rate of SD≥6 months/PR/ CR when treated with therapies targeting the PI3K/AKT/mTOR pathway than patients with only alterations in the PI3K/AKT/mTOR pathway (73% vs. 34%; P=0.0376) and remained on treatment longer (6.8 vs. 3.7 months; P=0.053). Higher response rates were seen in patients with simultaneous amplification in FGFR/FGF signaling and alterations in the PI3K/AKT/mTOR pathway who were treated with inhibitors of that pathway. PMID:27489863

  19. Presence of both alterations in FGFR/FGF and PI3K/AKT/mTOR confer improved outcomes for patients with metastatic breast cancer treated with PI3K/AKT/mTOR inhibitors.

    PubMed

    Wheler, Jennifer J; Atkins, Johnique T; Janku, Filip; Moulder, Stacy L; Stephens, Philip J; Yelensky, Roman; Valero, Vicente; Miller, Vincent; Kurzrock, Razelle; Meric-Bernstam, Funda

    2016-01-01

    There is limited data on co-expression of FGFR/FGR amplifications and PI3K/ AKT/mTOR alterations in breast cancer. Tumors from patients with metastatic breast cancer referred to our Phase I Program were analyzed by next generation sequencing (NGS). Genomic libraries were selected for all exons of 236 (or 182) cancer-related genes sequenced to average depth of >500× in a CLIA laboratory (Foundation Medicine, Cambridge, MA, USA) and analyzed for all classes of genomic alterations. We report genomic profiles of 112 patients with metastatic breast cancer, median age 55 years (range, 27-78). Twenty-four patients (21%) had at least one amplified FGFR or FGF. Fifteen of the 24 patients (63%) also had an alteration in the PI3K/ AKT/mTOR pathway. There was no association between alterations in FGFR/FGF and PI3K/AKT/mTOR (P=0.49). Patients with simultaneous amplification in FGFR/FGF signaling and the PI3K/AKT/mTOR pathway had a higher rate of SD≥6 months/PR/ CR when treated with therapies targeting the PI3K/AKT/mTOR pathway than patients with only alterations in the PI3K/AKT/mTOR pathway (73% vs. 34%; P=0.0376) and remained on treatment longer (6.8 vs. 3.7 months; P=0.053). Higher response rates were seen in patients with simultaneous amplification in FGFR/FGF signaling and alterations in the PI3K/AKT/mTOR pathway who were treated with inhibitors of that pathway. PMID:27489863

  20. PI3K-C2α: One enzyme for two products coupling vesicle trafficking and signal transduction.

    PubMed

    Campa, Carlo C; Franco, Irene; Hirsch, Emilio

    2015-06-22

    The spatial restriction of phosphorylated phosphoinositides generated downstream activated membrane receptors is critical for proper cell response to environmental cues. The α isoform of class II PI3Ks, PI3K-C2α, has emerged as a modulator of receptor localization, acting both in the control of receptor endocytosis and resensitization. This unexpectedly versatile enzyme was found to differentially produce two distinct 3-phosphorylated phosphoinositides and to selectively control distinct steps of vesicular traffic such as endocytosis and recycling. This review focuses on the latest discoveries regarding PI3K-C2α function in vesicle trafficking and its impact on cell biology and mammalian embryonic development.

  1. Discovery of drug-resistant and drug-sensitizing mutations in the oncogenic PI3K isoform p110α

    PubMed Central

    Zunder, Eli R.; Knight, Zachary A.; Houseman, Benjamin T.; Apsel, Beth; Shokat, Kevan M.

    2009-01-01

    Summary p110α (PIK3CA) is the most frequently mutated kinase in human cancer, and numerous drugs targeting this kinase are currently in pre-clinical development or early stage clinical trials. Clinical resistance to protein kinase inhibitors frequently results from point mutations that block drug binding; similar mutations in p110α are likely, but currently none have been reported. Using a S. cerevisiae screen against a structurally diverse panel of PI3K inhibitors, we have identified a potential hotspot for resistance mutations (I800), a drug-sensitizing mutation (L814C), and a surprising lack of resistance mutations at the “gatekeeper” residue. Our analysis further reveals that clinical resistance to these drugs may be attenuated by using multi-targeted inhibitors that simultaneously inhibit additional PI3K pathway members. Significance Point mutations that block drug binding are likely to be a major mechanism of clinical resistance to PI3K-targeted cancer therapy. Here we report resistance mutations in the oncogenic PI3K isoform p110α, as well as a drug-sensitizing mutation that will be useful for chemical genetic studies. This study anticipates p110α mutations that are likely to emerge against PI3K-targeted drugs, and identifies inhibitor classes that can overcome these resistance mutations. Our experiments in mammalian cells show that multi-targeted inhibitors with additional PI3K pathway targets are less susceptible to drug resistance than selective PI3K inhibitors. The screening protocol described here is applicable to several other drug targets that inhibit S. cerevisiae growth in addition to p110α. PMID:18691552

  2. The PI3K/Akt Pathway Regulates Oxygen Metabolism via Pyruvate Dehydrogenase (PDH)-E1α Phosphorylation

    PubMed Central

    Cerniglia, George J.; Dey, Souvik; Gallagher-Colombo, Shannon M.; Daurio, Natalie A; Tuttle, Stephen; Busch, Theresa M.; Lin, Alexander; Sun, Ramon; Esipova, Tatiana V.; Vinogradov, Sergei A.; Denko, Nicholas; Koumenis, Constantinos; Maity, Amit

    2015-01-01

    Inhibition of the PI3K/Akt pathway decreases hypoxia within SQ20B human head and neck cancer xenografts. We set out to understand the molecular mechanism underlying this observation. We measured oxygen consumption using both a Clark electrode and an extracellular flux analyzer. We made these measurements after various pharmacologic and genetic manipulations. Pharmacologic inhibition of the PI3K/mTOR pathway or genetic inhibition of Akt/PI3K decreased the oxygen consumption rate (OCR) in vitro in SQ20B and other cell lines by 30–40%. Pharmacologic inhibition of this pathway increased phosphorylation of the E1α subunit of the pyruvate dehydrogenase (PDH) complex on Ser293, which inhibits activity of this critical gatekeeper of mitochondrial respiration. Expressing wild type PTEN in a doxycycline-inducible manner in a cell line with mutant PTEN led to an increase in PDH-E1α phosphorylation and a decrease in OCR. Pre-treatment of SQ20B cells with dichloroacetate (DCA), which inhibits PDH-E1α phosphorylation by inhibiting dehydrogenase kinases (PDKs), reversed the decrease in OCR in response to PI3K/Akt/mTOR inhibition. Likewise, introduction of exogenous PDH-E1α that contains serine to alanine mutations, which can no longer be regulated by phosphorylation, also blunted the decrease in OCR seen with PI3K/mTOR inhibition. Our findings highlight an association between the PI3K/mTOR pathway and tumor cell oxygen consumption that is regulated in part by PDH phosphorylation. These results have important implications for understanding the effects PI3K pathway activation in tumor metabolism and also in designing cancer therapy trials that use inhibitors of this pathway. PMID:25995437

  3. PI3K/Akt signaling mediated Hexokinase-2 expression inhibits cell apoptosis and promotes tumor growth in pediatric osteosarcoma

    SciTech Connect

    Zhuo, Baobiao; Li, Yuan; Li, Zhengwei; Qin, Haihui; Sun, Qingzeng; Zhang, Fengfei; Shen, Yang; Shi, Yingchun; Wang, Rong

    2015-08-21

    Accumulating evidence has shown that PI3K/Akt pathway is frequently hyperactivated in osteosarcoma (OS) and contributes to tumor initiation and progression. Altered phenotype of glucose metabolism is a key hallmark of cancer cells including OS. However, the relationship between PI3K/Akt pathway and glucose metabolism in OS remains largely unexplored. In this study, we showed that elevated Hexokinase-2 (HK2) expression, which catalyzes the first essential step of glucose metabolism by conversion of glucose into glucose-6-phosphate, was induced by activated PI3K/Akt signaling. Immunohistochemical analysis showed that HK2 was overexpressed in 83.3% (25/30) specimens detected and was closely correlated with Ki67, a cell proliferation index. Silencing of endogenous HK2 resulted in decreased aerobic glycolysis as demonstrated by reduced glucose consumption and lactate production. Inhibition of PI3K/Akt signaling also suppressed aerobic glycolysis and this effect can be reversed by reintroduction of HK2. Furthermore, knockdown of HK2 led to increased cell apoptosis and reduced ability of colony formation; meanwhile, these effects were blocked by 2-Deoxy-D-glucose (2-DG), a glycolysis inhibitor through its actions on hexokinase, indicating that HK2 functions in cell apoptosis and growth were mediated by altered aerobic glycolysis. Taken together, our study reveals a novel relationship between PI3K/Akt signaling and aerobic glycolysis and indicates that PI3K/Akt/HK2 might be potential therapeutic approaches for OS. - Highlights: • PI3K/Akt signaling contributes to elevated expression of HK2 in osteosarcoma. • HK2 inhibits cell apoptosis and promotes tumor growth through enhanced Warburg effect. • Inhibition of glycolysis blocks the oncogenic activity of HK2.

  4. The pyrrolidinoindoline alkaloid Psm2 inhibits platelet aggregation and thrombus formation by affecting PI3K/Akt signaling

    PubMed Central

    Su, Xing-li; Su, Wen; Wang, Ying; Wang, Yue-hu; Ming, Xin; Kong, Yi

    2016-01-01

    Aim: Psm2, one of the pyrrolidinoindoline alkaloids isolated from whole Selaginella moellendorffii plants, has shown a potent antiplatelet activity. In this study, we further evaluated the antiplatelet effects of Psm2, and elucidated the underlying mechanisms. Methods: Human platelet aggregation in vitro and rat platelet aggregation ex vivo were investigated. Agonist-induced platelet aggregation was measured using a light transmission aggregometer. The antithrombotic effects of Psm2 were evaluated in arteriovenous shunt thrombosis model in rats. To elucidate the mechanisms underlying the antiplatelet activity of Psm2, ELISAs, Western blotting and molecular docking were performed. The bleeding risk of Psm2 administration was assessed in a mouse tail cutting model, and the cytotoxicity of Psm2 was measured with MTT assay in EA.hy926 cells. Results: Psm2 dose-dependently inhibited human platelet aggregation induced by ADP, U4619, thrombin and collagen with IC50 values of 0.64, 0.37, 0.35 and 0.87 mg/mL, respectively. Psm2 (1, 3, 10 mg/kg) administered to rats significantly inhibited platelet aggregation ex vivo induced by ADP. Psm2 (1, 3, 10 mg/mL, iv) administered to rats with the A–V shunt dose-dependently decreased the thrombus formation. Psm2 inhibited platelet adhesion to fibrinogen and collagen with IC50 values of 84.5 and 96.5 mg/mL, respectively, but did not affect the binding of fibrinogen to GPIIb/IIIa. Furthermore, Psm2 inhibited AktSer473 phosphorylation, but did not affect MAPK signaling and Src kinase activation. Molecular docking showed that Psm2 bound to phosphatidylinositol 3-kinase β (PI3Kβ) with a binding free energy of −13.265 kcal/mol. In addition, Psm2 did not cause toxicity in EA.hy926 cells and produced only slight bleeding in a mouse tail cutting model. Conclusion: Psm2 inhibits platelet aggregation and thrombus formation by affecting PI3K/Akt signaling. Psm2 may be a lead compound or drug candidate that could be developed for the

  5. Metformin prevents endoplasmic reticulum stress-induced apoptosis through AMPK-PI3K-c-Jun NH2 pathway

    USGS Publications Warehouse

    Jung, T.W.; Lee, M.W.; Lee, Y.-J.; Kim, S.M.

    2012-01-01

    Type 2 diabetes mellitus is thought to be partially associated with endoplasmic reticulum (ER) stress toxicity on pancreatic beta cells and the result of decreased insulin synthesis and secretion. In this study, we showed that a well-known insulin sensitizer, metformin, directly protects against dysfunction and death of ER stress-induced NIT-1 cells (a mouse pancreatic beta cell line) via AMP-activated protein kinase (AMPK) and phosphatidylinositol-3 (PI3) kinase activation. We also showed that exposure of NIT-1 cells to metformin (5mM) increases cellular resistance against ER stress-induced NIT-1 cell dysfunction and death. AMPK and PI3 kinase inhibitors abolished the effect of metformin on cell function and death. Metformin-mediated protective effects on ER stress-induced apoptosis were not a result of an unfolded protein response or the induced inhibitors of apoptotic proteins. In addition, we showed that exposure of ER stressed-induced NIT-1 cells to metformin decreases the phosphorylation of c-Jun NH(2) terminal kinase (JNK). These data suggest that metformin is an important determinant of ER stress-induced apoptosis in NIT-1 cells and may have implications for ER stress-mediated pancreatic beta cell destruction via regulation of the AMPK-PI3 kinase-JNK pathway.

  6. Licochalcone A induces autophagy through PI3K/Akt/mTOR inactivation and autophagy suppression enhances Licochalcone A-induced apoptosis of human cervical cancer cells.

    PubMed

    Tsai, Jen-Pi; Lee, Chien-Hsing; Ying, Tsung-Ho; Lin, Chu-Liang; Lin, Chia-Liang; Hsueh, Jung-Tsung; Hsieh, Yi-Hsien

    2015-10-01

    The use of dietary bioactive compounds in chemoprevention can potentially reverse, suppress, or even prevent cancer progression. However, the effects of licochalcone A (LicA) on apoptosis and autophagy in cervical cancer cells have not yet been clearly elucidated. In this study, LicA treatment was found to significantly induce the apoptotic and autophagic capacities of cervical cancer cells in vitro and in vivo. MTT assay results showed dose- and time-dependent cytotoxicity in four cervical cancer cell lines treated with LicA. We found that LicA induced mitochondria-dependent apoptosis in SiHa cells, with decreasing Bcl-2 expression. LicA also induced autophagy effects were examined by identifying accumulation of Atg5, Atg7, Atg12 and microtubule-associated protein 1 light chain 3 (LC3)-II. Treatment with autophagy-specific inhibitors (3-methyladenine and bafilomycin A1) enhanced LicA-induced apoptosis. In addition, we suggested the inhibition of phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of mTOR pathway by LicA. Furthermore, the inhibition of PI3K/Akt by LY294002/si-Akt or of mTOR by rapamycin augmented LicA-induced apoptosis and autophagy. Finally, the in vivo mice bearing a SiHa xenograft, LicA dosed at 10 or 20 mg/kg significantly inhibited tumor growth. Our findings demonstrate the chemotherapeutic potential of LicA for treatment of human cervical cancer.

  7. The Neuroprotection of Liraglutide Against Ischaemia-induced Apoptosis through the Activation of the PI3K/AKT and MAPK Pathways

    PubMed Central

    Zhu, Huili; Zhang, Yusheng; Shi, Zhongshan; Lu, Dan; Li, Tingting; Ding, Yan; Ruan, Yiwen; Xu, Anding

    2016-01-01

    Glucagon-like peptide-1 (GLP-1) is an incretin hormone that increases glucose-dependent insulin secretion to reduce the glucose level. Liraglutide, a long-acting GLP-1 analogue, has been found to have neuroprotective action in various experimental models. However, the protective mechanisms of liraglutide in ischaemic stroke remain unclear. Here, we demonstrated that liraglutide significantly decreased the infarct volume, improved neurologic deficits, and lowered stress-related hyperglycaemia without causing hypoglycaemia in a rat model of middle cerebral artery occlusion (MCAO). Liraglutide inhibited cell apoptosis by reducing excessive reactive oxygen species (ROS) and improving the function of mitochondria in neurons under oxygen glucose deprivation (OGD) in vitro and MCAO in vivo. Liraglutide up-regulated the phosphorylation of protein kinase B (AKT) and extracellular signal-regulated kinases (ERK) and inhibited the phosphorylation of c-jun-NH2-terminal kinase (JNK) and p38. Moreover, the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 and/or the ERK inhibitor U0126 counteracted the protective effect of liraglutide. Taken together, these results suggest that liraglutide exerts neuroprotective action against ischaemia-induced apoptosis through the reduction of ROS and the activation of the PI3K/AKT and mitogen-activated protein kinase (MAPK) pathways. Therefore, liraglutide has therapeutic potential for patients with ischaemic stroke, especially those with Type 2 diabetes mellitus or stress hyperglycaemia. PMID:27240461

  8. Quercetin Protects against Okadaic Acid-Induced Injury via MAPK and PI3K/Akt/GSK3β Signaling Pathways in HT22 Hippocampal Neurons.

    PubMed

    Jiang, Wei; Luo, Tao; Li, Sheng; Zhou, Yue; Shen, Xiu-Yin; He, Feng; Xu, Jie; Wang, Hua-Qiao

    2016-01-01

    Increasing evidence shows that oxidative stress and the hyperphosphorylation of tau protein play essential roles in the progression of Alzheimer's disease (AD). Quercetin is a major flavonoid that has anti-oxidant, anti-cancer and anti-inflammatory properties. We investigated the neuroprotective effects of quercetin to HT22 cells (a cell line from mouse hippocampal neurons). We found that Okadaic acid (OA) induced the hyperphosphorylation of tau protein at Ser199, Ser396, Thr205, and Thr231 and produced oxidative stress to the HT22 cells. The oxidative stress suppressed the cell viability and decreased the levels of lactate dehydrogenase (LDH), superoxide dismutase (SOD), mitochondria membrane potential (MMP) and Glutathione peroxidase (GSH-Px). It up-regulated malondialdehyde (MDA) production and intracellular reactive oxygen species (ROS). In addition, phosphoinositide 3 kinase/protein kinase B/Glycogen synthase kinase3β (PI3K/Akt/GSK3β) and mitogen activated protein kinase (MAPK) were also involved in this process. We found that pre-treatment with quercetin can inhibited OA-induced the hyperphosphorylation of tau protein and oxidative stress. Moreover, pre-treatment with quercetin not only inhibited OA-induced apoptosis via the reduction of Bax, and up-regulation of cleaved caspase 3, but also via the inhibition of PI3K/Akt/GSK3β, MAPKs and activation of NF-κB p65. Our findings suggest the therapeutic potential of quercetin to treat AD. PMID:27050422

  9. Antitumor effect of manumycin on colorectal cancer cells by increasing the reactive oxygen species production and blocking PI3K-AKT pathway

    PubMed Central

    Zhang, Jingyu; Jiang, Hua; Xie, Li; Hu, Jing; Li, Li; Yang, Mi; Cheng, Lei; Liu, Baorui; Qian, Xiaoping

    2016-01-01

    Manumycin is a natural, well-tolerated microbial metabolite and is regarded as a farnesyltransferase inhibitor. Some data suggest that manumycin inhibits proliferation of diverse cancer cells through various pathways. However, the antitumor effect of manumycin on colorectal cancer (CRC) remains unknown. In the present study, we investigated the antitumor effect of manumycin on CRC in vitro and in vivo. The results of cell viability assay revealed that the proliferation of the CRC cells was significantly inhibited by manumycin. Moreover, cell apoptosis induced by manumycin was also found in a time- and dose-dependent manner. Interestingly, treatment of the CRC cells with manumycin resulted in increased generation of reactive oxygen species. Subsequently, manumycin also decreased the phosphorylation of phosphatidylinositol 3-kinase (PI3K) and AKT, as well as the expression of caspase-9 and poly(ADP-ribose) polymerase (PARP) in a time-dependent manner. In addition, we found that N-acetyl-l-cysteine (NAC) attenuated the effect of manumycin on the PI3K-AKT pathway, and wortmannin reduced the effect of manumycin on caspase-9 and PARP expression. More importantly, the anticancer effect of manumycin was also observed in established tumor xenografts. Taken together, these findings supported the potential application of manumycin against colorectal carcinoma. PMID:27307747

  10. Daucus carota Pentane-Based Fractions Suppress Proliferation and Induce Apoptosis in Human Colon Adenocarcinoma HT-29 Cells by Inhibiting the MAPK and PI3K Pathways.

    PubMed

    Shebaby, Wassim N; Bodman-Smith, K B; Mansour, Anthony; Mroueh, Mohamad; Taleb, Robin I; El-Sibai, Mirvat; Daher, Costantine F

    2015-07-01

    Daucus carota L. ssp. carota (Apiacea, wild carrot, Queen Anne's lace) has been used in folk medicine throughout the world and recently was shown to possess anticancer and antioxidant activities. This study aims to determine the anticancer activity of the pentane fraction (F1) and the 1:1 pentane:diethyl ether fraction (F2) of the Daucus Carota oil extract (DCOE) against human colon adenocarcinoma cell lines (HT-29 and Caco-2). Treatment of cells with various concentrations of F1 or F2 fractions produced a dose-dependent inhibition of cell proliferation. Flow cytometric analysis indicated that both fractions induced sub-G1 phase accumulation and increased apoptotic cell death. Western blot revealed the activation of caspase-3, PARP cleavage, and a considerable increase in Bax and p53 levels, and a decrease in Bcl-2 level. Treatment of HT-29 cells with either fraction markedly decreased the levels of both phosphorylated Erk and Akt. Furthermore, the combined treatment of F1 or F2 with wortmannin showed no added inhibition of cell survival suggesting an effect of F1 or F2 through the phosphatidyl inositol 3-kinase (PI3K) pathway. This study proposes that DCOE fractions (F1 and F2) inhibit cell proliferation by inducing cell cycle arrest and apoptosis in HT-29 cells through the suppression of mitogen-activated protein kinase (MAPK)/Erk and PI3K/Akt pathways.

  11. FAK mediates a compensatory survival signal parallel to PI3K-AKT in PTEN-null T-ALL cells.

    PubMed

    You, Dewen; Xin, Junping; Volk, Andrew; Wei, Wei; Schmidt, Rachel; Scurti, Gina; Nand, Sucha; Breuer, Eun-Kyoung; Kuo, Paul C; Breslin, Peter; Kini, Ameet R; Nishimura, Michael I; Zeleznik-Le, Nancy J; Zhang, Jiwang

    2015-03-31

    Mutations and inactivation of phosphatase and tensin homolog deleted from chromosome 10 (PTEN) are observed in 15%-25% of cases of human T cell acute lymphoblastic leukemia (T-ALL). Pten deletion induces myeloproliferative disorders (MPDs), acute myeloid leukemia (AML), and/or T-ALL in mice. Previous studies attributed Pten-loss-related hematopoietic defects and leukemogenesis to excessive activation of phosphatidylinositol 3-kinase (PI3K)/AKT/mTOR signaling. Although inhibition of this signal dramatically suppresses the growth of PTEN-null T-ALL cells in vitro, treatment with inhibitors of this pathway does not cause a complete remission in vivo. Here, we report that focal adhesion kinase (Fak), a protein substrate of Pten, also contributes to T-ALL development in Pten-null mice. Inactivation of the FAK signaling pathway by either genetic or pharmacologic methods significantly sensitizes both murine and human PTEN-null T-ALL cells to PI3K/AKT/mTOR inhibition when cultured in vitro on feeder layer cells or a matrix and in vivo. PMID:25801032

  12. Nobiletin, a citrus flavonoid, suppresses invasion and migration involving FAK/PI3K/Akt and small GTPase signals in human gastric adenocarcinoma AGS cells.

    PubMed

    Lee, Yi-Chieh; Cheng, Tsan-Hwang; Lee, Jung-Shin; Chen, Jiun-Hwan; Liao, Yi-Chen; Fong, Yao; Wu, Cheng-Hsun; Shih, Yuan-Wei

    2011-01-01

    Nobiletin, a compound isolated from citrus fruits, is a polymethoxylated flavone derivative shown to have anti-inflammatory, antitumor, and neuroprotective properties. This study has investigated that nobiletin exerted inhibitory effects on the cell adhesion, invasion, and migration abilities of a highly metastatic AGS cells under non-cytotoxic concentrations. Data also showed nobiletin could inhibit the activation of focal adhesion kinase (FAK) and phosphoinositide-3-kinase/Akt (PI3K/Akt) involved in the downregulation of the enzyme activities, protein expressions, messenger RNA levels of matrix metalloproteinase-2 (MMP-2), and matrix metalloproteinase-2 (MMP-9). Also, our data revealed that nobiletin inhibited FAK/PI3K/Akt with concurrent reduction in the protein expressions of Ras, c-Raf, Rac-1, Cdc42, and RhoA by western blotting, whereas the protein level of RhoB increased progressively. Otherwise, nobiletin-treated AGS cells showed tremendously decreased in the phosphorylation and degradation of inhibitor of kappaBα (IκBα), the nuclear level of NF-κB, and the binding ability of NF-κB to NF-κB response element. Furthermore, nobiletin significantly decreased the levels of phospho-Akt and MMP-2/9 in Akt1-cDNA-transfected cells concomitantly with a marked reduction in cell invasion and migration. These results suggest that nobiletin can reduce invasion and migration of AGS cells, and such a characteristic may be of great value in the development of a potential cancer therapy.

  13. The molecular mechanism of polygalasaponin F-mediated decreases in TNFα: emphasizing the role of the TLR4-PI3K/AKT-NF-κB pathway.

    PubMed

    Yan, Wen-Fen; Shao, Qian-Hang; Zhang, Dong-Ming; Yuan, Yu-He; Chen, Nai-Hong

    2015-01-01

    Polygalasaponin F (PS-F), an oleanane-type triterpenoid saponin extracted from Polygala japonica, decreases the release of the inflammatory cytokine tumor necrosis factor α (TNFα), but the precise molecular mechanisms by which this event occurs are not fully understood. To study the anti-neuroinflammatory mechanisms of PS-F, enzyme-linked immunosorbent assay was used to detect the secretion of TNFα from BV-2 microglial cells. Nuclear proteins extracted from BV-2 microglial cells stimulated by lipopolysaccharide (LPS) and pretreated with/without inhibitors were measured by Western blotting, and cell viability was evaluated by MTT analysis. The results indicated that inhibition of toll-like receptor (TLR) 4 (CLI-095 1 μg/ml), phosphatidylinositol 3-kinase (PI3K) (Ly294002 10 μM) or IκBα phosphorylation (Bay11-7082 10 μM) completely prevents the release of TNFα induced by LPS without affecting cell viability and attenuated the nuclear translocation of p65 stimulated by LPS. In addition, PS-F exhibited a similar trend regarding TNFα release, AKT phosphorylation and NF-κB translocation. These results suggest that PS-F reduces neuroinflammatory cytokine secretion through the regulation of the TLR4-PI3K/AKT-NF-κB signaling pathway. PMID:26235355

  14. EPO-dependent activation of PI3K/Akt/FoxO3a signalling mediates neuroprotection in in vitro and in vivo models of Parkinson's disease.

    PubMed

    Jia, Yu; Mo, Shi-Jing; Feng, Qi-Qi; Zhan, Ma-Li; OuYang, Li-Si; Chen, Jia-Chang; Ma, Yu-Xin; Wu, Jia-Jia; Lei, Wan-Long

    2014-05-01

    Erythropoietin (EPO) may become a potential therapeutic candidate for the treatment of the neurodegenerative disorder -- Parkinson's disease (PD), since EPO has been found to prevent neuron apoptosis through the activation of cell survival signalling. However, the underlying mechanisms of how EPO exerts its neuroprotective effect are not fully elucidated. Here we investigated the mechanism by which EPO suppressed 6-hydroxydopamine (6-OHDA)-induced neuron death in in vitro and in vivo models of PD. EPO knockdown conferred 6-OHDA-induced cytotoxicity. This effect was reversed by EPO administration. Treatment of PC12 cells with EPO greatly diminished the toxicity induced by 6-OHDA in a dose- and time-dependent manner. EPO effectively reduced apoptosis of striatal neurons and induced a significant improvement on the neurological function score in the rat models of PD. Furthermore, EPO increased the expression of phosphorylated Akt and phosphorylated FoxO3a, and abrogated the 6-OHDA-induced dysregulation of Bcl-2, Bax and Caspase-3 in PC12 cells and in striatal neurons. Meanwhile, the EPO-dependent neuroprotection was notably reversed by pretreatment with LY294002, a specific inhibitor of phosphatidylinositol 3-kinase (PI3K). Our data suggest that PI3K/Akt/FoxO3a signalling pathway may be a possible mechanism involved in the neuroprotective effect of EPO in PD. PMID:24390959

  15. Quercetin Protects against Okadaic Acid-Induced Injury via MAPK and PI3K/Akt/GSK3β Signaling Pathways in HT22 Hippocampal Neurons

    PubMed Central

    Li, Sheng; Zhou, Yue; Shen, Xiu-Yin; He, Feng; Xu, Jie; Wang, Hua-Qiao

    2016-01-01

    Increasing evidence shows that oxidative stress and the hyperphosphorylation of tau protein play essential roles in the progression of Alzheimer’s disease (AD). Quercetin is a major flavonoid that has anti-oxidant, anti-cancer and anti-inflammatory properties. We investigated the neuroprotective effects of quercetin to HT22 cells (a cell line from mouse hippocampal neurons). We found that Okadaic acid (OA) induced the hyperphosphorylation of tau protein at Ser199, Ser396, Thr205, and Thr231 and produced oxidative stress to the HT22 cells. The oxidative stress suppressed the cell viability and decreased the levels of lactate dehydrogenase (LDH), superoxide dismutase (SOD), mitochondria membrane potential (MMP) and Glutathione peroxidase (GSH-Px). It up-regulated malondialdehyde (MDA) production and intracellular reactive oxygen species (ROS). In addition, phosphoinositide 3 kinase/protein kinase B/Glycogen synthase kinase3β (PI3K/Akt/GSK3β) and mitogen activated protein kinase (MAPK) were also involved in this process. We found that pre-treatment with quercetin can inhibited OA-induced the hyperphosphorylation of tau protein and oxidative stress. Moreover, pre-treatment with quercetin not only inhibited OA-induced apoptosis via the reduction of Bax, and up-regulation of cleaved caspase 3, but also via the inhibition of PI3K/Akt/GSK3β, MAPKs and activation of NF-κB p65. Our findings suggest the therapeutic potential of quercetin to treat AD. PMID:27050422

  16. Fucoidan from sea cucumber Cucumaria frondosa exhibits anti-hyperglycemic effects in insulin resistant mice via activating the PI3K/PKB pathway and GLUT4.

    PubMed

    Wang, Yiming; Wang, Jingfeng; Zhao, Yanlei; Hu, Shiwei; Shi, Di; Xue, Changhu

    2016-01-01

    The present study investigated the anti-hyperglycemic properties and mechanisms of fucoidan, isolated from Cucumaria frondosa (Cf-FUC), in insulin resistant mice. Male C57BL/6J mice were fed regular diet or high-fat/high-sucrose diet for 19 weeks. Model animals were dietary administrated either rosiglitazone (RSG, 1 mg/kg·bw), fucoidan (Cf-FUC, 80 mg/kg·bw) or their combinations. Results showed that Cf-FUC significantly reduced fasting blood glucose and insulin levels, and enhanced glucose tolerance and insulin tolerance in insulin-resistant mice. Quantitative real-time PCR analysis showed that Cf-FUC increased the mRNA expressions of insulin receptors (IR), insulin receptor substrate 1 (IRS-1), phosphatidylinositol 3 kinase (PI3K), protein kinase B (PKB), and glucose transporter 4 (GLUT4). Western blot assays demonstrated that Cf-FUC showed no effect on total protein expression but nevertheless enhanced the phosphorylation of proteins listed above and increased translocation of GLUT4 to the cell membrane. Furthermore, Cf-FUC enhanced the effects of RSG. These results indicated that Cf-FUC exhibited significant anti-hyperglycemic effects via activating PI3K/PKB pathway and GLUT4 in skeletal muscle and adipose tissue.

  17. The molecular mechanism of polygalasaponin F-mediated decreases in TNFα: emphasizing the role of the TLR4-PI3K/AKT-NF-κB pathway.

    PubMed

    Yan, Wen-Fen; Shao, Qian-Hang; Zhang, Dong-Ming; Yuan, Yu-He; Chen, Nai-Hong

    2015-01-01

    Polygalasaponin F (PS-F), an oleanane-type triterpenoid saponin extracted from Polygala japonica, decreases the release of the inflammatory cytokine tumor necrosis factor α (TNFα), but the precise molecular mechanisms by which this event occurs are not fully understood. To study the anti-neuroinflammatory mechanisms of PS-F, enzyme-linked immunosorbent assay was used to detect the secretion of TNFα from BV-2 microglial cells. Nuclear proteins extracted from BV-2 microglial cells stimulated by lipopolysaccharide (LPS) and pretreated with/without inhibitors were measured by Western blotting, and cell viability was evaluated by MTT analysis. The results indicated that inhibition of toll-like receptor (TLR) 4 (CLI-095 1 μg/ml), phosphatidylinositol 3-kinase (PI3K) (Ly294002 10 μM) or IκBα phosphorylation (Bay11-7082 10 μM) completely prevents the release of TNFα induced by LPS without affecting cell viability and attenuated the nuclear translocation of p65 stimulated by LPS. In addition, PS-F exhibited a similar trend regarding TNFα release, AKT phosphorylation and NF-κB translocation. These results suggest that PS-F reduces neuroinflammatory cytokine secretion through the regulation of the TLR4-PI3K/AKT-NF-κB signaling pathway.

  18. Inhibition of the PI3K/Akt/mTOR signaling pathway in diffuse large B-cell lymphoma: current knowledge and clinical significance.

    PubMed

    Majchrzak, Agata; Witkowska, Magdalena; Smolewski, Piotr

    2014-09-11

    Diffuse large B-cell lymphoma (DLBCL) is one of the most common non-Hodgkin lymphomas in adults. The disease is very heterogeneous in its presentation, that is DLBCL patients may differ from each other not only in regard to histology of tissue infiltration, clinical course or response to treatment, but also in respect to diversity in gene expression profiling. A growing body of knowledge on the biology of DLBCL, including abnormalities in intracellular signaling, has allowed the development of new treatment strategies, specifically directed against lymphoma cells. The phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway plays an important role in controlling proliferation and survival of tumor cells in various types of malignancies, including DLBCL, and therefore it may be a promising target for therapeutic intervention. Currently, novel anticancer drugs are undergoing assessment in different phases of clinical trials in aggressive lymphomas, with promising outcomes. In this review we present a state of art review on various classes of small molecule inhibitors selectively involving PI3K/Akt/mTOR pathway and their clinical potential in this disease.

  19. Downregulation of PI3K/Akt/mTOR signaling pathway in curcumin-induced autophagy in APP/PS1 double transgenic mice.

    PubMed

    Wang, Chen; Zhang, Xiong; Teng, Zhipeng; Zhang, Tong; Li, Yu

    2014-10-01

    Autophagy is a lysosomal degradation pathway, which is essential for cell survival, proliferation, differentiation and homeostasis. It is well known that beta-amyloid (Aβ) aggregation is one of key characteristics for Alzheimer's disease (AD), which triggers a complex pathological cascade, leading to neurodegeneration. Recent studies have shown that Aβ peptide is generated from amyloid β precursor protein (APP) during autophagic turnover of APP-rich organelles by autophagy. Aβ generation during normal autophagy is subsequently degraded by lysosomes. Curcumin, a nature plant extraction, has been reported to inhibit the generation and deposition of Aβ; however, the underlying mechanisms are not fully understood yet. In the present study, we reported that curcumin treatment not only attenuated cognitive impairment detected by Morris water maze test, but also inhibited the generation of Aβ investigated by immunohistochemistry in APP/PS1 double transgenic AD mice. Moreover, curcumin induced autophagy in the mice, evidenced by LC3 immunofluorescence analysis and western blot assays on LC3. Furthermore, we found that curcumin significantly decreased the expression of Phosphatidylinositol 3-Kinase (PI3K), phosphorylated Akt and rapamycin (mTOR) at protein levels, respectively. Taken together, our data suggests that curcumin inhibits Aβ generation and induces of autophagy by downregulating PI3K/Akt/mTOR signaling pathway, and further shows a neuroprotective effect. Meanwhile curcumin might be a candidate neuroprotective agent for AD patients treatment by inducing autophagy.

  20. C-terminal domain of p42 Ebp1 is essential for down regulation of p85 subunit of PI3K, inhibiting tumor growth

    PubMed Central

    Hwang, Inwoo; Kim, Chung Kwon; Ko, Hyo Rim; Park, Kye Won; Cho, Sung-Woo; Ahn, Jee-Yin

    2016-01-01

    Potential tumor suppressor p42, ErbB3-binding protein 1 (EBP1) inhibits phosphoinositide 3-kinase (PI3K) activity reducing the p85 regulatory subunit. In this study, we demonstrated that overexpression of p42 promoted not only a reduction of wild type of p85 subunit but also oncogenic mutant forms of p85 which were identified in human cancers. Moreover, we identified the small fragment of C-terminal domain of p42 is sufficient to exhibit tumor suppressing activity of p42-WT, revealing that this small fragment (280–394) of p42 is required for the binding of both HSP70 and CHIP for a degradation of p85. Furthermore, we showed the small fragment of p42 markedly inhibited the tumor growth in mouse xenograft models of brain and breast cancer, resembling tumor suppressing activity of p42. Through identification of the smallest fragment of p42 that is responsible for its tumor suppressor activity, our findings represent a novel approach for targeted therapy of cancers that overexpress PI3K. PMID:27464702

  1. Feedbacks and adaptive capabilities of the PI3K/Akt/mTOR axis in acute myeloid leukemia revealed by pathway selective inhibition and phosphoproteome analysis.

    PubMed

    Bertacchini, J; Guida, M; Accordi, B; Mediani, L; Martelli, A M; Barozzi, P; Petricoin, E; Liotta, L; Milani, G; Giordan, M; Luppi, M; Forghieri, F; De Pol, A; Cocco, L; Basso, G; Marmiroli, S

    2014-11-01

    Acute myeloid leukemia (AML) primary cells express high levels of phosphorylated Akt, a master regulator of cellular functions regarded as a promising drug target. By means of reverse phase protein arrays, we examined the response of 80 samples of primary cells from AML patients to selective inhibitors of the phosphatidylinositol 3 kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) axis. We confirm that >60% of the samples analyzed are characterized by high pathway phosphorylation. Unexpectedly, however, we show here that targeting Akt and mTOR with the specific inhibitors Akti 1/2 and Torin1, alone or in combination, result in paradoxical Akt phosphorylation and activation of downstream signaling in 70% of the samples. Indeed, we demonstrate that cropping Akt or mTOR activity can stabilize the Akt/mTOR downstream effectors Forkhead box O and insulin receptor substrate-1, which in turn potentiate signaling through upregulation of the expression/phosphorylation of selected growth factor receptor tyrosine kinases (RTKs). Activation of RTKs in turn reactivates PI3K and downstream signaling, thus overruling the action of the drugs. We finally demonstrate that dual inhibition of Akt and RTKs displays strong synergistic cytotoxic effects in AML cells and downmodulates Akt signaling to a much greater extent than either drug alone, and should therefore be explored in AML clinical setting.

  2. Interleukin-21 promotes osteoclastogenesis in RAW264.7 cells through the PI3K/AKT signaling pathway independently of RANKL.

    PubMed

    Xing, Rui; Zhang, Yingjian; Li, Changhong; Sun, Lin; Yang, Lin; Zhao, Jinxia; Liu, Xiangyuan

    2016-10-01

    Cytokines play a key role in the bone destruction of rheumatoid arthritis (RA). Interleukin-21 (IL-21) promotes osteoclastogenesis in RA in a receptor activator of nuclear factor-κB ligand (RANKL)-dependent way. Whether IL-21 is capable of promoting osteoclastogenesis directly in the absence of RANKL remains unknown. In the present study, we examined the osteoclastogenic activity of IL-21 in RAW264.7 cells in the absence of RANKL. We found that IL-21 enhanced osteoclastogenesis and this was demonstrated by increased numbers of tartrate-resistant acid phosphatase (TRAP)-positive stained, multinucleated cells compared with the negative control. Western blot analysis and immunocytochemistry showed the positive expression of calcitonin receptor (CTR) in the IL-21 group. RT-PCR and RT-qPCR also verified the increased mRNA expression of CTR and cathepsin K in the IL-21 group compared with the negative control. The scanning electronic microscope images showed a few resorption pits on the bone slices cultured with IL-21. The phosphoinositide 3-kinase (PI3K)/AKT pathway inhibitor LY294002 significantly suppressed IL-21-induced osteoclastogenesis. Taken together, these findings suggest that IL-21 has direct osteoclastogenic potential independently of RANKL. IL-21 may promote osteoclastogenesis through the PI3K/AKT signaling pathway. Therapy targeting IL-21 may be of value in preventing bone erosions in patients with RA. PMID:27599586

  3. Resveratrol Regulates Activated Hepatic Stellate Cells by Modulating NF-κB and the PI3K/Akt Signaling Pathway.

    PubMed

    Zhang, De-Quan; Sun, Peng; Jin, Quan; Li, Xia; Zhang, Yu; Zhang, Yu-Jing; Wu, Yan-Ling; Nan, Ji-Xing; Lian, Li-Hua

    2016-01-01

    In the present study, we investigated whether resveratrol could suppress the hepatic fibrogenesis in activated hepatic stellate cells. The immortalized rat hepatic stellate cells, t-HSC/Cl-6, were treated with resveratrol 1 h prior to lipopolysaccharide (LPS, 1 μg/mL). Resveratrol decreased t-HSC/Cl-6 cell viability at much lower concentrations within 24 h. Resveratrol pretreatment also decreased the LPS-induced protein expression of α-SMA and collagen I. In addition, resveratrol significantly reduced the protein expression of Toll-like receptor 4 (TLR4) and myeloid differentiation primary response gene 88 (MyD88), and the expression of phosphorylated phosphatidylinositol 3-kinase (PI3K) and phosphorylated serine/threonine kinase B (Akt). Moreover, resveratrol markedly blocked the translocation of nuclear factor (NF)-κB in LPS-activated HSCs. Furthermore, resveratrol inhibited HSCs activation through stimulating LXRβ, but did not influence LXRα. Overall, we conclude that the antifibrotic effect of resveratrol is the result of blocking NF-κB activation and PI3K/Akt phosphorylation, which inhibits HSC activation to obstruct liver fibrosis. Thus, resveratrol may be a natural agent for preventing hepatic fibrosis.

  4. Interleukin-21 promotes osteoclastogenesis in RAW264.7 cells through the PI3K/AKT signaling pathway independently of RANKL

    PubMed Central

    Xing, Rui; Zhang, Yingjian; Li, Changhong; Sun, Lin; Yang, Lin; Zhao, Jinxia; Liu, Xiangyuan

    2016-01-01

    Cytokines play a key role in the bone destruction of rheumatoid arthritis (RA). Interleukin-21 (IL-21) promotes osteoclastogenesis in RA in a receptor activator of nuclear factor-κB ligand (RANKL)-dependent way. Whether IL-21 is capable of promoting osteoclastogenesis directly in the absence of RANKL remains unknown. In the present study, we examined the osteoclastogenic activity of IL-21 in RAW264.7 cells in the absence of RANKL. We found that IL-21 enhanced osteoclastogenesis and this was demonstrated by increased numbers of tartrate-resistant acid phosphatase (TRAP)-positive stained, multinucleated cells compared with the negative control. Western blot analysis and immunocytochemistry showed the positive expression of calcitonin receptor (CTR) in the IL-21 group. RT-PCR and RT-qPCR also verified the increased mRNA expression of CTR and cathepsin K in the IL-21 group compared with the negative control. The scanning electronic microscope images showed a few resorption pits on the bone slices cultured with IL-21. The phosphoinositide 3-kinase (PI3K)/AKT pathway inhibitor LY294002 significantly suppressed IL-21-induced osteoclastogenesis. Taken together, these findings suggest that IL-21 has direct osteoclastogenic potential independently of RANKL. IL-21 may promote osteoclastogenesis through the PI3K/AKT signaling pathway. Therapy targeting IL-21 may be of value in preventing bone erosions in patients with RA. PMID:27599586

  5. Catalase expression in MCF-7 breast cancer cells is mainly controlled by PI3K/Akt/mTor signaling pathway.

    PubMed

    Glorieux, Christophe; Auquier, Julien; Dejeans, Nicolas; Sid, Brice; Demoulin, Jean-Baptiste; Bertrand, Luc; Verrax, Julien; Calderon, Pedro Buc

    2014-05-15

    Catalase is an antioxidant enzyme that catalyzes mainly the transformation of hydrogen peroxide into water and oxygen. Although catalase is frequently down-regulated in tumors the underlying mechanism remains unclear. Few transcription factors have been reported to directly bind the human catalase promoter. Among them FoxO3a has been proposed as a positive regulator of catalase expression. Therefore, we decided to study the role of the transcription factor FoxO3a and the phosphatidylinositol-3 kinase (PI3K) signaling pathway, which regulates FoxO3a, in the expression of catalase. To this end, we developed an experimental model of mammary breast MCF-7 cancer cells that acquire resistance to oxidative stress, the so-called Resox cells, in which catalase is overexpressed as compared with MCF-7 parental cell line. In Resox cells, Akt expression is decreased but its phosphorylation is enhanced when compared with MCF-7 cells. A similar profile is observed for FoxO3a, with less total protein but more phosphorylated FoxO3a in Resox cells, correlating with its higher Akt activity. The modulation of FoxO3a expression by knockdown and overexpression strategies did not affect catalase expression, neither in MCF-7 nor in Resox cells. Inhibition of PI3K and mTOR by LY295002 and rapamycin, respectively, decreases the phosphorylation of downstream targets (i.e. GSK3β and p70S6K) and leads to an increase of catalase expression only in MCF-7 but not in Resox cells. In conclusion, FoxO3a does not appear to play a critical role in the regulation of catalase expression in both cancer cells. Only MCF-7 cells are sensitive and dependent on PI3K/Akt/mTOR signaling.

  6. Effect of Compound Chuanxiong Capsule on Inflammatory Reaction and PI3K/Akt/NF-κB Signaling Pathway in Atherosclerosis.

    PubMed

    Kang, Qunfu; Liu, Weihong; Liu, Hongxu; Zhou, Mingxue

    2015-01-01

    Compound Chuanxiong Capsule (CCC), a Chinese herbal compound, can exhibit antiatherosclerotic effect; however, its mechanism is still unclear. This study is designed to study the mechanism of CCC on atherosclerosis in the ApoE-knockout (ApoE(-/-)) mice fed with a high-fat diet. After 6 weeks of high-fat feeding, 40 ApoE(-/-) mice were randomized (n = 10) and treated with lipitor, high-dose or low-dose CCC, or distilled water (ApoE(-/-) group) for 7 weeks. The blood lipids in serum and the plaque areas of the mice were measured and the mRNA expressions of phosphatidylinositol-3-kinases (PI3K), Akt, nuclear factor-kappa B (NF-κB), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) of the aortae were determined. The data showed that CCC can significantly decrease the levels of blood lipids, atherosclerosis index, and plaque areas and increase collagen proportion in plaques as compared with the untreated mice (p < 0.05, p < 0.01). In addition, CCC can significantly reduce the mRNA expressions of PI3K, Akt, NF-κB, IL-6, and TNF-α in the mice fed with a high-fat diet (p < 0.001). Thus, we concluded that CCC can inhibit inflammatory reaction in the ApoE(-/-) mice fed with a high-fat diet. This mechanism may be attributed to regulating PI3K/Akt/NF-κB signaling pathway. PMID:26539229

  7. The neuroprotective action of pyrroloquinoline quinone against glutamate-induced apoptosis in hippocampal neurons is mediated through the activation of PI3K/Akt pathway

    SciTech Connect

    Zhang Qi; Shen Mi; Ding Mei; Shen Dingding; Ding Fei

    2011-04-01

    Pyrroloquinoline quinone (PQQ), a cofactor in several enzyme-catalyzed redox reactions, possesses a potential capability of scavenging reactive oxygen species (ROS) and inhibiting cell apoptosis. In this study, we investigated the effects of PQQ on glutamate-induced cell death in primary cultured hippocampal neurons and the possible underlying mechanisms. We found that glutamate-induced apoptosis in cultured hippocampal neurons was significantly attenuated by the ensuing PQQ treatment, which also inhibited the glutamate-induced increase in Ca2+ influx, caspase-3 activity, and ROS production, and reversed the glutamate-induced decrease in Bcl-2/Bax ratio. The examination of signaling pathways revealed that PQQ treatment activated the phosphorylation of Akt and suppressed the glutamate-induced phosphorylation of c-Jun N-terminal protein kinase (JNK). And inhibition of phosphatidylinositol-3-kinase (PI3K)/Akt cascade by LY294002 and wortmannin significantly blocked the protective effects of PQQ, and alleviated the increase in Bcl-2/Bax ratio. Taken together, our results indicated that PQQ could protect primary cultured hippocampal neurons against glutamate-induced cell damage by scavenging ROS, reducing Ca2+ influx, and caspase-3 activity, and suggested that PQQ-activated PI3K/Akt signaling might be responsible for its neuroprotective action through modulation of glutamate-induced imbalance between Bcl-2 and Bax. - Research Highlights: >PQQ attenuated glutamate-induced cell apoptosis of cultured hippocampal neurons. >PQQ inhibited glutamate-induced Ca{sup 2+} influx and caspase-3 activity. >PQQ reduced glutamate-induced increase in ROS production. >PQQ affected phosphorylation of Akt and JNK signalings after glutamate injury. >PI3K/Akt was required for neuroprotection of PQQ by modulating Bcl-2/Bax ratio.

  8. Effect of Compound Chuanxiong Capsule on Inflammatory Reaction and PI3K/Akt/NF-κB Signaling Pathway in Atherosclerosis

    PubMed Central

    Kang, Qunfu; Liu, Weihong; Liu, Hongxu; Zhou, Mingxue

    2015-01-01

    Compound Chuanxiong Capsule (CCC), a Chinese herbal compound, can exhibit antiatherosclerotic effect; however, its mechanism is still unclear. This study is designed to study the mechanism of CCC on atherosclerosis in the ApoE-knockout (ApoE−/−) mice fed with a high-fat diet. After 6 weeks of high-fat feeding, 40 ApoE−/− mice were randomized (n = 10) and treated with lipitor, high-dose or low-dose CCC, or distilled water (ApoE−/− group) for 7 weeks. The blood lipids in serum and the plaque areas of the mice were measured and the mRNA expressions of phosphatidylinositol-3-kinases (PI3K), Akt, nuclear factor-kappa B (NF-κB), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) of the aortae were determined. The data showed that CCC can significantly decrease the levels of blood lipids, atherosclerosis index, and plaque areas and increase collagen proportion in plaques as compared with the untreated mice (p < 0.05, p < 0.01). In addition, CCC can significantly reduce the mRNA expressions of PI3K, Akt, NF-κB, IL-6, and TNF-α in the mice fed with a high-fat diet (p < 0.001). Thus, we concluded that CCC can inhibit inflammatory reaction in the ApoE−/− mice fed with a high-fat diet. This mechanism may be attributed to regulating PI3K/Akt/NF-κB signaling pathway. PMID:26539229

  9. 2,2',4,4'-Tetrabromodiphenyl ether promotes human neuroblastoma SH-SY5Y cells migration via the GPER/PI3K/Akt signal pathway.

    PubMed

    Tian, P-C; Wang, H-L; Chen, G-H; Luo, Q; Chen, Z; Wang, Y; Liu, Y-F

    2016-02-01

    Neuroblastoma is the predominant tumor of early childhood. 2,2',4,4'-Tetrabromodiphenyl ether (BDE-47) has the highest concentration among all polybrominated diphenyl ether (PBDE) congeners in human body, particularly for children. Considering that accumulating evidences showed developmental neurotoxicity of PBDE, there is an urgent need to investigate the effects of BDE-47 on the development of neuroblastoma. This study revealed that BDE-47 had limited effects on the cytotoxicity while significantly increased the in vitro migration and invasion of human neuroblastoma SH-SY5Y cells. This was further confirmed by the results that BDE-47 treatment significantly downregulated the expression of E-cadherin and zona occludin-1 and upregulated the expression of matrix metalloproteinase-9 (MMP-9). Silencing of MMP-9 by specific small interfering RNA significantly abolished the BDE-47-induced migration and invasion of SH-SY5Y cells. Further, the signals G protein-coupled estrogen receptor 1 (GPER)/phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/protein kinase B (Akt) mediated the BDE-47-induced upregulation of MMP-9 and in vitro migration of SH-SY5Y cells since G15 (GPER inhibitor) and LY 294002 (PI3K/Akt inhibitor) significantly abolished the effects of BDE-47. Our results revealed that BDE-47 significantly triggered the metastasis of human neuroblastoma SH-SY5Y cells via upregulation of MMP-9 by the GPER/PI3K/Akt signal pathway. This study revealed for the first time that BDE-47 can promote the migration of SH-SY5Y cells. It also provided a better understanding about the metastasis of human neuroblastoma induced by environmental endocrine disruptors.

  10. Ellagic acid protects endothelial cells from oxidized low-density lipoprotein-induced apoptosis by modulating the PI3K/Akt/eNOS pathway

    SciTech Connect

    Ou, Hsiu-Chung; Lee, Wen-Jane; Lee, Shin-Da; Huang, Chih-Yang; Chiu, Tsan-Hung; Tsai, Kun-Ling; Hsu, Wen-Cheng; Sheu, Wayne Huey-Herng

    2010-10-15

    Endothelial apoptosis is a driving force in atherosclerosis development. Oxidized low-density lipoprotein (oxLDL) promotes inflammatory and thrombotic processes and is highly atherogenic, as it stimulates macrophage cholesterol accumulation and foam cell formation. Previous studies have shown that the phosphatidylinositol 3-kinase/Akt/endothelial nitric oxide synthase/nitric oxide (PI3K/Akt/eNOS/NO) pathway is involved in oxLDL-induced endothelial apoptosis. Ellagic acid, a natural polyphenol found in berries and nuts, has in recent years been the subject of intense research within the fields of cancer and inflammation. However, its protective effects against oxLDL-induced injury in vascular endothelial cells have not been clarified. In the present study, we investigated the anti-apoptotic effect of ellagic acid in human umbilical vein endothelial cells (HUVECs) exposed to oxLDL and explored the possible mechanisms. Our results showed that pretreatment with ellagic acid (5-20 {mu}M) significantly attenuated oxLDL-induced cytotoxicity, apoptotic features, and generation of reactive oxygen species (ROS). In addition, the anti-apoptotic effect of ellagic acid was partially inhibited by a PI3K inhibitor (wortmannin) and a specific eNOS inhibitor (cavtratin) but not by an ERK inhibitor (PD98059). In exploring the underlying mechanisms of ellagic acid action, we found that oxLDL decreased Akt and eNOS phosphorylation, which in turn activated NF-{kappa}B and downstream pro-apoptotic signaling events including calcium accumulation, destabilization of mitochondrial permeability, and disruption of the balance between pro- and anti-apoptotic Bcl-2 proteins. Those alterations induced by oxLDL, however, were attenuated by pretreatment with ellagic acid. The inhibition of oxLDL-induced endothelial apoptosis by ellagic acid is due at least in part to its anti-oxidant activity and its ability to modulate the PI3K/Akt/eNOS signaling pathway.

  11. Nerve Regeneration Potential of Protocatechuic Acid in RSC96 Schwann Cells by Induction of Cellular Proliferation and Migration through IGF-IR-PI3K-Akt Signaling.

    PubMed

    Ju, Da-Tong; Liao, Hung-En; Shibu, Marthandam Asokan; Ho, Tsung-Jung; Padma, Viswanadha Vijaya; Tsai, Fuu-Jen; Chung, Li-Chin; Day, Cecilia Hsuan; Lin, Chien-Chung; Huang, Chih-Yang

    2015-12-31

    Peripheral nerve injuries, caused by accidental trauma, acute compression or surgery, often result in temporary or life-long neuronal dysfunctions and inflict great economic or social burdens on the patients. Nerve cell proliferation is an essential process to restore injured nerves of adults. Schwann cells play a crucial role in endogenous repair of peripheral nerves due to their ability to proliferate, migrate and provide trophic support to axons via expression of various neurotrophic factors, such as the nerve growth factor (NGF), especially after nerve injury. Protocatechuic acid (PCA) is a dihydroxybenzoic acid, a type of phenolic acid, isolated from the kernels of Alpinia oxyphylla Miq (AOF), a traditional Chinese herbal medicine the fruits of which are widely used as a tonic, aphrodisiac, anti-salivation and anti-diarrheatic. This study investigated the molecular mechanisms by which PCA induces Schwann cell proliferation by activating IGF-IR-PI3K-Akt pathway. Treatment with PCA induces phosphorylation of the insulin-like growth factor-I (IGF-I)-mediated phosphatidylinositol 3 kinase/serine - threonine kinase (PI3K/Akt) pathway, and activates expression of cell nuclear antigen (PCNA) in a dose-dependent manner. Cell cycle analysis after 18 h of treatment showed that proliferation of the RSC96 cells was enhanced by PCA treatment. The PCA induced proliferation was accompanied by modulation in the expressions of cell cycle proteins cyclin D1, cyclin E and cyclin A. Knockdown of PI3K using small interfering RNA (siRNA) and inhibition of IGF-IR receptor resulted in the reduction in cell survival proteins. The results collectively showed that PCA treatment promoted cell proliferation and cell survival via IGF-I signaling. PMID:26717920

  12. Heat Stress-Induced PI3K/mTORC2-Dependent AKT Signaling Is a Central Mediator of Hepatocellular Carcinoma Survival to Thermal Ablation Induced Heat Stress.

    PubMed

    Thompson, Scott M; Callstrom, Matthew R; Jondal, Danielle E; Butters, Kim A; Knudsen, Bruce E; Anderson, Jill L; Lien, Karen R; Sutor, Shari L; Lee, Ju-Seog; Thorgeirsson, Snorri S; Grande, Joseph P; Roberts, Lewis R; Woodrum, David A

    2016-01-01

    Thermal ablative therapies are important treatment options in the multidisciplinary care of patients with hepatocellular carcinoma (HCC), but lesions larger than 2-3 cm are plagued with high local recurrence rates and overall survival of these patients remains poor. Currently no adjuvant therapies exist to prevent local HCC recurrence in patients undergoing thermal ablation. The molecular mechanisms mediating HCC resistance to thermal ablation induced heat stress and local recurrence remain unclear. Here we demonstrate that the HCC cells with a poor prognostic hepatic stem cell subtype (Subtype HS) are more resistant to heat stress than HCC cells with a better prognostic hepatocyte subtype (Subtype HC). Moreover, sublethal heat stress rapidly induces phosphoinositide 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) dependent-protein kinase B (AKT) survival signaling in HCC cells in vitro and at the tumor ablation margin in vivo. Conversely, inhibition of PI3K/mTOR complex 2 (mTORC2)-dependent AKT phosphorylation or direct inhibition of AKT function both enhance HCC cell killing and decrease HCC cell survival to sublethal heat stress in both poor and better prognostic HCC subtypes while mTOR complex 1 (mTORC1)-inhibition has no impact. Finally, we showed that AKT isoforms 1, 2 and 3 are differentially upregulated in primary human HCCs and that overexpression of AKT correlates with worse tumor biology and pathologic features (AKT3) and prognosis (AKT1). Together these findings define a novel molecular mechanism whereby heat stress induces PI3K/mTORC2-dependent AKT survival signaling in HCC cells and provide a mechanistic rationale for adjuvant AKT inhibition in combination with thermal ablation as a strategy to enhance HCC cell killing and prevent local recurrence, particularly at the ablation margin. PMID:27611696

  13. The PI3K/mTOR inhibitor PF-04691502 induces apoptosis and inhibits microenvironmental signaling in CLL and the Eµ-TCL1 mouse model.

    PubMed

    Blunt, Matthew D; Carter, Matthew J; Larrayoz, Marta; Smith, Lindsay D; Aguilar-Hernandez, Maria; Cox, Kerry L; Tipton, Thomas; Reynolds, Mark; Murphy, Sarah; Lemm, Elizabeth; Dias, Samantha; Duncombe, Andrew; Strefford, Jonathan C; Johnson, Peter W M; Forconi, Francesco; Stevenson, Freda K; Packham, Graham; Cragg, Mark S; Steele, Andrew J

    2015-06-25

    Current treatment strategies for chronic lymphocytic leukemia (CLL) involve a combination of conventional chemotherapeutics, monoclonal antibodies, and targeted signaling inhibitors. However, CLL remains largely incurable, with drug resistance and treatment relapse a common occurrence, leading to the search for novel treatments. Mechanistic target of rapamycin (mTOR)-specific inhibitors have been previously assessed but their efficacy is limited due to a positive feedback loop via mTOR complex 2 (mTORC2), resulting in activation of prosurvival signaling. In this study, we show that the dual phosphatidylinositol 3-kinase (PI3K)/mTOR inhibitor PF-04691502 does not induce an mTORC2 positive feedback loop similar to other PI3K inhibitors but does induce substantial antitumor effects. PF-04691502 significantly reduced survival coincident with the induction of Noxa and Puma, independently of immunoglobulin heavy chain variable region mutational status, CD38, and ZAP-70 expression. PF-04691502 inhibited both anti-immunoglobulin M-induced signaling and overcame stroma-induced survival signals and migratory stimuli from CXCL12. Equivalent in vitro activity was seen in the Eμ-TCL1 murine model of CLL. In vivo, PF-04691502 treatment of tumor-bearing animals resulted in a transient lymphocytosis, followed by a clear reduction in tumor in the blood, bone marrow, spleen, and lymph nodes. These data indicate that PF-04691502 or other dual PI3K/mTOR inhibitors in development may prove efficacious for the treatment of CLL, increasing our armamentarium to successfully manage this disease.

  14. Apoptosis Induction of Human Prostate Carcinoma DU145 Cells by Diallyl Disulfide via Modulation of JNK and PI3K/AKT Signaling Pathways

    PubMed Central

    Shin, Dong Yeok; Kim, Gi-Young; Lee, Jun Hyuk; Choi, Byung Tae; Yoo, Young Hyun; Choi, Yung Hyun

    2012-01-01

    Diallyl disulfide (DADS), a sulfur compound derived from garlic, has various biological properties, such as anticancer, antiangiogenic and anti-inflammatory effects. However, the mechanisms of action underlying the compound’s anticancer activity have not been fully elucidated. In this study, the apoptotic effects of DADS were investigated in DU145 human prostate carcinoma cells. Our results showed that DADS markedly inhibited the growth of the DU145 cells by induction of apoptosis. Apoptosis was accompanied by modulation of Bcl-2 and inhibitor of apoptosis protein (IAP) family proteins, depolarization of the mitochondrial membrane potential (MMP, ΔΨm) and proteolytic activation of caspases. We also found that the expression of death-receptor 4 (DR4) and Fas ligand (FasL) proteins was increased and that the level of intact Bid proteins was down-regulated by DADS. Moreover, treatment with DADS induced phosphorylation of mitogen-activated protein kinases (MAPKs), including extracellular-signal regulating kinase (ERK), p38 MAPK and c-Jun N-terminal kinase (JNK). A specific JNK inhibitor, SP600125, significantly blocked DADS-induced-apoptosis, whereas inhibitors of the ERK (PD98059) and p38 MAPK (SB203580) had no effect. The induction of apoptosis was also accompanied by inactivation of phosphatidylinositol 3-kinase (PI3K)/Akt and the PI3K inhibitor LY29004 significantly increased DADS-induced cell death. These findings provide evidence demonstrating that the proapoptotic effect of DADS is mediated through the activation of JNK and the inhibition of the PI3K/Akt signaling pathway in DU145 cells. PMID:23203057

  15. Chinese herbal medicine formula tao hong si wu decoction protects against cerebral ischemia-reperfusion injury via PI3K/Akt and the Nrf2 signaling pathway.

    PubMed

    Li, Li; Yang, Na; Nin, Ling; Zhao, Zhilong; Chen, Lu; Yu, Jie; Jiang, Zhuyun; Zhong, Zhendong; Zeng, Daiwen; Qi, Hongyi; Xu, Xiaoyu

    2015-01-01

    The Chinese herbal medicine formula Tao Hong Si Wu decoction (THSWD) is traditionally used for the prevention and treatment of ischemic stroke. Transcription factor NF-E2-related factor 2 (Nrf2) regulates a battery of phase II enzymes and is known as the major mechanism of cellular defense against oxidative stress. The present study aimed to explore the potential effect of THSWD on the Nrf2 signaling pathway and the consequent effect during cerebral ischemia-reperfusion (I/R) injury. We found that THSWD reduced infarct volume and improved neurological function in a rat stroke model induced by middle cerebral artery occlusion (MCAO). Additionally, heme oxygenase 1 (HO-1), a key endogenous antioxidant enzyme regulated by Nrf2, was significantly further induced by THSWD in this in vivo model. In neuronal-like PC12 cells, THSWD remarkably up-regulated HO-1 expression and promoted Nrf2 nuclear translocation. Furthermore, phosphatidylinositol 3-kinase (PI3K)/Akt kinase was found to be involved in the upstream of Nrf2 regulation. In an in vitro oxygen-glucose deprivation/reperfusion (OGD-Rep) model, THSWD treatment significantly reduced cell death induced by OGD-Rep insult. Importantly, the protective action was attenuated while PI3K activity was inhibited by a specific inhibitor, LY294002, and the Nrf2 signaling pathway was blocked by antioxidant response element (ARE) decoy oligonucleotides. Collectively, these results demonstrated that THSWD exhibited notable neuroprotective properties in vitro and in vivo and activation of PI3K/Akt and the Nrf2 signaling pathway may be, at least in part, responsible for the protection. This study provides a better understanding of the molecular mechanism underlying the traditional use of the Chinese herbal medicine formula THSWD.

  16. Heat Stress-Induced PI3K/mTORC2-Dependent AKT Signaling Is a Central Mediator of Hepatocellular Carcinoma Survival to Thermal Ablation Induced Heat Stress.

    PubMed

    Thompson, Scott M; Callstrom, Matthew R; Jondal, Danielle E; Butters, Kim A; Knudsen, Bruce E; Anderson, Jill L; Lien, Karen R; Sutor, Shari L; Lee, Ju-Seog; Thorgeirsson, Snorri S; Grande, Joseph P; Roberts, Lewis R; Woodrum, David A

    2016-01-01

    Thermal ablative therapies are important treatment options in the multidisciplinary care of patients with hepatocellular carcinoma (HCC), but lesions larger than 2-3 cm are plagued with high local recurrence rates and overall survival of these patients remains poor. Currently no adjuvant therapies exist to prevent local HCC recurrence in patients undergoing thermal ablation. The molecular mechanisms mediating HCC resistance to thermal ablation induced heat stress and local recurrence remain unclear. Here we demonstrate that the HCC cells with a poor prognostic hepatic stem cell subtype (Subtype HS) are more resistant to heat stress than HCC cells with a better prognostic hepatocyte subtype (Subtype HC). Moreover, sublethal heat stress rapidly induces phosphoinositide 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) dependent-protein kinase B (AKT) survival signaling in HCC cells in vitro and at the tumor ablation margin in vivo. Conversely, inhibition of PI3K/mTOR complex 2 (mTORC2)-dependent AKT phosphorylation or direct inhibition of AKT function both enhance HCC cell killing and decrease HCC cell survival to sublethal heat stress in both poor and better prognostic HCC subtypes while mTOR complex 1 (mTORC1)-inhibition has no impact. Finally, we showed that AKT isoforms 1, 2 and 3 are differentially upregulated in primary human HCCs and that overexpression of AKT correlates with worse tumor biology and pathologic features (AKT3) and prognosis (AKT1). Together these findings define a novel molecular mechanism whereby heat stress induces PI3K/mTORC2-dependent AKT survival signaling in HCC cells and provide a mechanistic rationale for adjuvant AKT inhibition in combination with thermal ablation as a strategy to enhance HCC cell killing and prevent local recurrence, particularly at the ablation margin.

  17. Heat Stress-Induced PI3K/mTORC2-Dependent AKT Signaling Is a Central Mediator of Hepatocellular Carcinoma Survival to Thermal Ablation Induced Heat Stress

    PubMed Central

    Thompson, Scott M.; Callstrom, Matthew R.; Jondal, Danielle E.; Butters, Kim A.; Knudsen, Bruce E.; Anderson, Jill L.; Lien, Karen R.; Sutor, Shari L.; Lee, Ju-Seog; Thorgeirsson, Snorri S.; Grande, Joseph P.; Roberts, Lewis R.; Woodrum, David A.

    2016-01-01

    Thermal ablative therapies are important treatment options in the multidisciplinary care of patients with hepatocellular carcinoma (HCC), but lesions larger than 2–3 cm are plagued with high local recurrence rates and overall survival of these patients remains poor. Currently no adjuvant therapies exist to prevent local HCC recurrence in patients undergoing thermal ablation. The molecular mechanisms mediating HCC resistance to thermal ablation induced heat stress and local recurrence remain unclear. Here we demonstrate that the HCC cells with a poor prognostic hepatic stem cell subtype (Subtype HS) are more resistant to heat stress than HCC cells with a better prognostic hepatocyte subtype (Subtype HC). Moreover, sublethal heat stress rapidly induces phosphoinositide 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) dependent-protein kinase B (AKT) survival signaling in HCC cells in vitro and at the tumor ablation margin in vivo. Conversely, inhibition of PI3K/mTOR complex 2 (mTORC2)-dependent AKT phosphorylation or direct inhibition of AKT function both enhance HCC cell killing and decrease HCC cell survival to sublethal heat stress in both poor and better prognostic HCC subtypes while mTOR complex 1 (mTORC1)-inhibition has no impact. Finally, we showed that AKT isoforms 1, 2 and 3 are differentially upregulated in primary human HCCs and that overexpression of AKT correlates with worse tumor biology and pathologic features (AKT3) and prognosis (AKT1). Together these findings define a novel molecular mechanism whereby heat stress induces PI3K/mTORC2-dependent AKT survival signaling in HCC cells and provide a mechanistic rationale for adjuvant AKT inhibition in combination with thermal ablation as a strategy to enhance HCC cell killing and prevent local recurrence, particularly at the ablation margin. PMID:27611696

  18. Glucagon-like peptide-1 protects cardiomyocytes from advanced oxidation protein product-induced apoptosis via the PI3K/Akt/Bad signaling pathway.

    PubMed

    Zhang, Hua; Xiong, Zhouyi; Wang, Jiao; Zhang, Shuangshuang; Lei, Lei; Yang, Li; Zhang, Zhen

    2016-02-01

    Cardiomyocyte apoptosis is a major event in the pathogenesis of diabetic cardiomyopathy. Currently, no single effective treatment for diabetic cardiomyopathy exists. The present study investigated whether advanced oxidative protein products (AOPPs) have a detrimental role in the survival of cardiomyocytes and if glucagon-like peptide-1 (GLP-1) exerts a cardioprotective effect under these circumstances. The present study also aimed to determine the underlying mechanisms. H9c2 cells were exposed to increasing concentrations of AOPPs in the presence or absence of GLP-1, and the viability and apoptotic rate were detected using a cell counting kit-8 assay and flow cytometry, respectively. In addition, a phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) inhibitor, LY294002, was employed to illustrate the mechanism of the antiapoptotic effect of GLP-1. The expression levels of the apoptotic-associated proteins, Akt, B-cell lymphoma (Bcl)-2, Bcl-2-associated death promoter (Bad), Bcl-2-associated X protein (Bax) and caspase-3 were measured by western blotting. It was revealed that GLP-1 significantly attenuated AOPP-induced cell toxicity and apoptosis. AOPPs inactivated the phosphorylation of Akt, reduced the phosphorylation of Bad, decreased the expression of Bcl-2, increased the expression of Bax and the activation of caspase-3 in H9c2 cells. GLP-1 reversed the above changes induced by AOPPs and the protective effects of GLP-1 were abolished by the PI3K inhibitor, LY294002. In conclusion, the present data suggested that GLP-1 protected cardiomyocytes against AOPP-induced apoptosis, predominantly via the PI3K/Akt/Bad pathway. These results provided a conceivable mechanism for the development of diabetic cardiomyopathy and rendered a novel application of GLP-1 exerting favorable cardiac effects for the treatment of diabetic cardiomyopathy.

  19. Glucagon-like peptide-1 protects cardiomyocytes from advanced oxidation protein product-induced apoptosis via the PI3K/Akt/Bad signaling pathway

    PubMed Central

    ZHANG, HUA; XIONG, ZHOUYI; WANG, JIAO; ZHANG, SHUANGSHUANG; LEI, LEI; YANG, LI; ZHANG, ZHEN

    2016-01-01

    Cardiomyocyte apoptosis is a major event in the pathogenesis of diabetic cardiomyopathy. Currently, no single effective treatment for diabetic cardiomyopathy exists. The present study investigated whether advanced oxidative protein products (AOPPs) have a detrimental role in the survival of cardiomyocytes and if glucagon-like peptide-1 (GLP-1) exerts a cardioprotective effect under these circumstances. The present study also aimed to determine the underlying mechanisms. H9c2 cells were exposed to increasing concentrations of AOPPs in the presence or absence of GLP-1, and the viability and apoptotic rate were detected using a cell counting kit-8 assay and flow cytometry, respectively. In addition, a phosphatidylino-sitol-4,5-bisphosphate 3-kinase (PI3K) inhibitor, LY294002, was employed to illustrate the mechanism of the antiapoptotic effect of GLP-1. The expression levels of the apoptotic-associated proteins, Akt, B-cell lymphoma (Bcl)-2, Bcl-2-associated death promoter (Bad), Bcl-2-associated X protein (Bax) and caspase-3 were measured by western blotting. It was revealed that GLP-1 significantly attenuated AOPP-induced cell toxicity and apoptosis. AOPPs inactivated the phosphorylation of Akt, reduced the phosphorylation of Bad, decreased the expression of Bcl-2, increased the expression of Bax and the activation of caspase-3 in H9c2 cells. GLP-1 reversed the above changes induced by AOPPs and the protective effects of GLP-1 were abolished by the PI3K inhibitor, LY294002. In conclusion, the present data suggested that GLP-1 protected cardiomyocytes against AOPP-induced apoptosis, predominantly via the PI3K/Akt/Bad pathway. These results provided a conceivable mechanism for the development of diabetic cardiomyopathy and rendered a novel application of GLP-1 exerting favorable cardiac effects for the treatment of diabetic cardiomyopathy. PMID:26717963

  20. Effects of orexin A on glucose metabolism in human hepatocellular carcinoma in vitro via PI3K/Akt/mTOR-dependent and -independent mechanism.

    PubMed

    Liu, Yuanyuan; Zhao, Yuyan; Guo, Lei

    2016-01-15

    Orexins are hypothalamic neuropeptides that regulate food intake, energy homeostasis, reward system and sleep/wakefulness states. The purpose of this study was to investigate the effects of orexin A on glucose metabolism in human hepatocellular carcinoma cell line, Hep3B, and determine the possible mechanisms. Hep3B cells were incubated with different concentrations of orexin A (10(-9)-10(-7) M) in vitro in the presence or absence of the orexin receptor 1 (OX1R) inhibitor (SB334867), Akt inhibitor (PF-04691502) and mammalian target of rapamycin (mTOR) inhibitor (temsirolimus). Subsequently, OX1R protein expression, glucose transporter 1 (GLUT1) expression, glucose uptake, the mRNA expression of lactate dehydrogenase (LDHA), pyruvate dehydrogenase kinase 1 (PDK1) and pyruvate dehydrogenase B (PDHB), lactate generation and mitochondrial pyruvate dehydrogenase (PDH) enzyme activity were measured. The activity of phosphoinositide 3-kinase (PI3K)/Akt/mTOR signaling was also determined. OX1R was expressed in hepatoma tissues and Hep3B cells. Stimulation of the Hep3B cells with orexin A resulted in a dose-dependent increase of GLUT1 expression and glucose uptake, which was associated with the activation of PI3K/Akt/mTOR pathway. Further, orexin A increased PDHB expression and PDH enzyme activity, decreased LDHA, PDK1 mRNA levels and lactate generation independent of PI3K/Akt/mTOR pathway. Our results demonstrated that orexin A directed the cellular metabolism towards mitochondrial glucose oxidation rather than glycolysis. These findings provide functional evidence of the metabolic actions of orexin A in hepatocellular carcinoma cells.

  1. Quantitative Proteomics Reveals that miR-155 Regulates the PI3K-AKT Pathway in Diffuse Large B-Cell Lymphoma

    PubMed Central

    Huang, Xin; Shen, Yulei; Liu, Miao; Bi, Chengfeng; Jiang, Chunsun; Iqbal, Javeed; McKeithan, Timothy W.; Chan, Wing C.; Ding, Shi-Jian; Fu, Kai

    2013-01-01

    The aberrant expression of microRNA-155 (miR-155), which has emerged as having a significant impact on the biological characteristics of lymphocytes, plays important roles in B-cell malignancies, such as diffuse large B-cell lymphoma (DLBCL). DLBCL is the most common non–Hodgkin's lymphoma in the adult population, accounting for approximately 40% of newly diagnosed non–Hodgkin's lymphoma cases globally. To determine the specific function of miR-155, a quantitative proteomics approach was applied to examine the inhibitory effects of miR-155 on protein synthesis in DLBCL cells. PIK3R1 (p85α), a negative regulator of the phosphatidylinositol 3-kinase (PI3K)–AKT pathway, was identified as a direct target of miR-155. A luciferase reporter was repressed through the direct interaction of miR-155 and the p85α 3′-untranslated region, and overexpression of miR-155 down-regulated both the transcription and translation of p85α. The PI3K-AKT signaling pathway was highly activated by the sustained overexpression of miR-155 in DHL16 cells, whereas knockdown of miR-155 in OCI-Ly3 cells diminished AKT activity. Taken together, our results reveal a novel target involved in miR-155 biological characteristics and provide a molecular link between the overexpression of miR-155 and the activation of PI3K-AKT in DLBCL. PMID:22609116

  2. Macrophage SR-BI mediates efferocytosis via Src/PI3K/Rac1 signaling and reduces atherosclerotic lesion necrosis[S

    PubMed Central

    Tao, Huan; Yancey, Patricia G.; Babaev, Vladimir R.; Blakemore, John L.; Zhang, Youmin; Ding, Lei; Fazio, Sergio; Linton, MacRae F.

    2015-01-01

    Macrophage apoptosis and efferocytosis are key determinants of atherosclerotic plaque inflammation and necrosis. Bone marrow transplantation studies in ApoE- and LDLR-deficient mice revealed that hematopoietic scavenger receptor class B type I (SR-BI) deficiency results in severely defective efferocytosis in mouse atherosclerotic lesions, resulting in a 17-fold higher ratio of free to macrophage-associated dead cells in lesions containing SR-BI−/− cells, 5-fold more necrosis, 65.2% less lesional collagen content, nearly 7-fold higher dead cell accumulation, and 2-fold larger lesion area. Hematopoietic SR-BI deletion elicited a maladaptive inflammatory response [higher interleukin (IL)-1β, IL-6, and TNF-α lower IL-10 and transforming growth factor β]. Efferocytosis of apoptotic thymocytes was reduced by 64% in SR-BI−/− versus WT macrophages, both in vitro and in vivo. In response to apoptotic cells, macrophage SR-BI bound with phosphatidylserine and induced Src phosphorylation and cell membrane recruitment, which led to downstream activation of phosphoinositide 3-kinase (PI3K) and Ras-related C3 botulinum toxin substrate 1 (Rac1) for engulfment and clearance of apoptotic cells, as inhibition of Src decreased PI3K, Rac1-GTP, and efferocytosis in WT cells. Pharmacological inhibition of Rac1 reduced macrophage efferocytosis in a SR-BI-dependent fashion, and activation of Rac1 corrected the defective efferocytosis in SR-BI−/− macrophages. Thus, deficiency of macrophage SR-BI promotes defective efferocytosis signaling via the Src/PI3K/Rac1 pathway, resulting in increased plaque size, necrosis, and inflammation. PMID:26059978

  3. ERK 1/2 and PI-3 kinase pathways as a potential mechanism of ghrelin action on cell proliferation and apoptosis in the porcine ovarian follicular cells.

    PubMed

    Rak-Mardyla, A; Gregoraszczuk, E L

    2010-08-01

    Recently, we reported the stimulatory effect of ghrelin on ovarian cell proliferation in parallel with the inhibitory action of ghrelin on cell apoptosis. The aim of the presented data propose local activation of extracellular signal-regulated protein kinase 1 and 2 (ERK 1/2) and phosphoinositide-3 (PI-3) kinase pathways as a mechanism of ghrelin effect in the porcine ovary. To test this hypothesis, action of ghrelin on levels of ERK 1/2 with PI-3 kinase activity and protein expression using ELISA and western blot analysis, respectively, was examined. Additionally, to determine which pathways (ERK 1/2 or PI-3 kinase) are the potential signals of ghrelin-mediated cell proliferation and apoptosis in ovarian cells, we used PD098059 (50 microM) and wortmannin (200 microM), well-known inhibitors of these kinases. Treatment of ovarian coculture cells with ghrelin (100, 250, 500 and 1000 pg/ml) showed stimulation of phospho-ERK 1/2 levels and PI-3 kinase activity, with the maximum effect observed after 15 min of cell incubation. Additionally, western blot analysis indicated that ghrelin increased expression of both kinases. Moreover, ghrelin used in combination with PD098059 or wortmannin significantly decreased cell proliferation, which was measured by the Alamar Blue assay and increased apoptosis, which was measured by caspase - 3 activity and DNA fragmentation. In conclusion, these results suggest that the ERK 1/2 and PI-3 kinase pathways may be potential signals of ghrelin mediate the cell proliferation and apoptosis of ovary cells.

  4. Receptor for advanced glycation end products inhibits proliferation in osteoblast through suppression of Wnt, PI3K and ERK signaling

    SciTech Connect

    Li, Guofeng; Xu, Jingren; Li, Zengchun

    2012-07-13

    Highlights: Black-Right-Pointing-Pointer RAGE overexpression suppresses cell proliferation in MC3T3-E1 cells. Black-Right-Pointing-Pointer RAGE overexpression decreases Wnt/{beta}-catenin signaling. Black-Right-Pointing-Pointer RAGE overexpression decreases ERK and PI3K signaling. Black-Right-Pointing-Pointer Inhibition of Wnt signaling abolishes PI3K signaling restored by RAGE blockade. Black-Right-Pointing-Pointer Inhibition of Wnt signaling abolishes ERK signaling restored by RAGE blockade. -- Abstract: Expression of receptor for advanced glycation end products (RAGE) plays a crucial role in bone metabolism. However, the role of RAGE in the control of osteoblast proliferation is not yet evaluated. In the present study, we demonstrate that RAGE overexpression inhibits osteoblast proliferation in vitro. The negative regulation of RAGE on cell proliferation results from suppression of Wnt, PI3K and ERK signaling, and is restored by RAGE neutralizing antibody. Prevention of Wnt signaling using Sfrp1 or DKK1 rescues RAGE-decreased PI3K and ERK signaling and cell proliferation, indicating that the altered cell growth in RAGE overexpressing cells is in part secondary to alterations in Wnt signaling. Consistently, RAGE overexpression inhibits the expression of Wnt targets cyclin D1 and c-myc, which is partially reversed by RAGE blockade. Overall, these results suggest that RAGE inhibits osteoblast proliferation via suppression of Wnt, PI3K and ERK signaling, which provides novel mechanisms by which RAGE regulates osteoblast growth.

  5. The tumor suppressor p53 fine-tunes reactive oxygen species levels and neurogenesis via PI3 kinase signaling.

    PubMed

    Forsberg, Kirsi; Wuttke, Anja; Quadrato, Giorgia; Chumakov, Peter M; Wizenmann, Andrea; Di Giovanni, Simone

    2013-09-01

    Mounting evidence points to a role for endogenous reactive oxygen species (ROS) in cell signaling, including in the control of cell proliferation, differentiation, and fate. However, the function of ROS and their molecular regulation in embryonic mouse neural progenitor cells (eNPCs) has not yet been clarified. Here, we describe that physiological ROS are required for appropriate timing of neurogenesis in the developing telencephalon in vivo and in cultured NPCs, and that the tumor suppressor p53 plays a key role in the regulation of ROS-dependent neurogenesis. p53 loss of function leads to elevated ROS and early neurogenesis, while restoration of p53 and antioxidant treatment partially reverse the phenotype associated with premature neurogenesis. Furthermore, we describe that the expression of a number of neurogenic and oxidative stress genes relies on p53 and that both p53 and ROS-dependent induction of neurogenesis depend on PI3 kinase/phospho-Akt signaling. Our results suggest that p53 fine-tunes endogenous ROS levels to ensure the appropriate timing of neurogenesis in eNPCs. This may also have implications for the generation of tumors of neurodevelopmental origin.

  6. Novel anti-microbial peptide SR-0379 accelerates wound healing via the PI3 kinase/Akt/mTOR pathway.

    PubMed

    Tomioka, Hideki; Nakagami, Hironori; Tenma, Akiko; Saito, Yoshimi; Kaga, Toshihiro; Kanamori, Toshihide; Tamura, Nao; Tomono, Kazunori; Kaneda, Yasufumi; Morishita, Ryuichi

    2014-01-01

    We developed a novel cationic antimicrobial peptide, AG30/5C, which demonstrates angiogenic properties similar to those of LL-37 or PR39. However, improvement of its stability and cost efficacy are required for clinical application. Therefore, we examined the metabolites of AG30/5C, which provided the further optimized compound, SR-0379. SR-0379 enhanced the proliferation of human dermal fibroblast cells (NHDFs) via the PI3 kinase-Akt-mTOR pathway through integrin-mediated interactions. Furthermore SR-0379 promoted the tube formation of human umbilical vein endothelial cells (HUVECs) in co-culture with NHDFs. This compound also displays antimicrobial activities against a number of bacteria, including drug-resistant microbes and fungi. We evaluated the effect of SR-0379 in two different would-healing models in rats, the full-thickness defects under a diabetic condition and an acutely infected wound with full-thickness defects and inoculation with Staphylococcus aureus. Treatment with SR-0379 significantly accelerated wound healing when compared to fibroblast growth factor 2 (FGF2). The beneficial effects of SR-0379 on wound healing can be explained by enhanced angiogenesis, granulation tissue formation, proliferation of endothelial cells and fibroblasts and antimicrobial activity. These results indicate that SR-0379 may have the potential for drug development in wound repair, even under especially critical colonization conditions. PMID:24675668

  7. The PI3K pathway balances self-renewal and differentiation of nephron progenitor cells through β-catenin signaling.

    PubMed

    Lindström, Nils Olof; Carragher, Neil Oliver; Hohenstein, Peter

    2015-04-14

    Nephron progenitor cells differentiate to form nephrons during embryonic kidney development. In contrast, self-renewal maintains progenitor numbers and premature depletion leads to impaired kidney function. Here we analyze the PI3K pathway as a point of convergence for the multiple pathways that are known to control self-renewal in the kidney. We demonstrate that a reduction in PI3K signaling triggers premature differentiation of the progenitors and activates a differentiation program that precedes the mesenchymal-to-epithelial transition through ectopic activation of the β-catenin pathway. Therefore, the combined output of PI3K and other pathways fine-tunes the balance between self-renewal and differentiation in nephron progenitors.

  8. Salinomycin causes migration and invasion of human fibrosarcoma cells by inducing MMP-2 expression via PI3-kinase, ERK-1/2 and p38 kinase pathways.

    PubMed

    Yu, Seon-Mi; Kim, Song Ja

    2016-06-01

    Salinomycin (SAL) is a polyether ionophore antibiotic that has recently been shown to regulate a variety of cellular responses in various human cancer cells. However, the effects of SAL on metastatic capacity of HT1080 human fibrosarcoma cells have not been elucidated. We investigated the effect of SAL on migration and invasion, with emphasis on the expression and activation of matrix metalloproteinase (MMP)-2 in HT1080 human fibrosarcoma cells. Treatment of SAL promoted the expression and activation of MMP-2 in a dose- and time-dependent manner, as detected by western blot analysis, gelatin zymography, and real-time polymerase chain reaction. SAL also increased metastatic capacities, as determined by an increase in the migration and invasion of cells using the wound healing assay and the invasion assay, respectively. To confirm the detailed molecular mechanisms of these effects, we measured the activation of phosphoinositide 3 kinase (PI3-kinase) and mitogen-activated protein kinase (MAPK)s (ERK-1/2 and p38 kinase), as detected by the phosphorylated proteins through western blot analysis. SAL treat