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Sample records for 3-kinase pi3k activation

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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

  6. 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 ...

  7. 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

  8. 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

  9. 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.

  10. 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

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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

  18. 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

  19. 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.

  20. 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

  1. 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

  2. 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.

  3. 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.

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. 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

  20. 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.

  1. 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

  2. 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.

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  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. 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.

  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 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.

  16. 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.

  17. 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.

  18. 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

  19. 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

  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. 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

  2. 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.

  3. 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

  4. 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.

  5. 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

  6. 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

  7. New strategy for in vitro activation of primordial follicles with mTOR and PI3K stimulators.

    PubMed

    Sun, Xinhui; Su, Yiping; He, Yuanlin; Zhang, Jing; Liu, Wenwen; Zhang, Huilin; Hou, Zheng; Liu, Jiayin; Li, Jing

    2015-01-01

    It had been known for decades that primordial follicles in mammalian ovaries are assembled with definite numbers and represent the ovarian reserve throughout the reproductive life. Intra-oocyte PI3K/mTOR pathways have been indicated to play a central role on the activation of primordial follicles. Genetic modified mouse models with chronic activation of PI3K/mTOR signals in primordial oocytes showed premature activation of all primordial follicles and eventually their exhaustion. On the other hand, this may suggest that, unlike chronic activation of PI3K/mTOR, its acute activation in infertility would activate primordial follicles, permitting fertility during the treatment. Previously, PI3K stimulators were reported as a temporary measure to accelerate primordial follicle activation and follicular development in both mouse and human, and were applied in the treatment of infertility in premature ovarian failure (POF) patients. To address whether mTOR stimulators could play similar role in the process, we transiently treated neonatal and aged mouse ovaries with mTOR stimulators-phosphatidic acid (PA) and propranolol. Our results demonstrated the stimulators increased activation of primordial follicles and the production of progeny. Human ovarian cortex cubes were also treated with mTOR or/and PI3K stimulators in vitro. When they were used separately, both of them showed similar promotive effects on primordial follicles. Surprisingly, after joint-treatment with the 2 kinds of stimulators together, synergistic effects on follicular development were observed. Based on increased efficiency of follicular activation in humans, here we propose in vitro transient treatment with mTOR and PI3K stimulators as an optimized protocol for the application in different clinical conditions with limited follicle reserve.

  8. 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.

  9. 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

  10. 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.

  11. Imp2 regulates GBM progression by activating IGF2/PI3K/Akt pathway

    PubMed Central

    Mu, Qingchun; Wang, Lijun; Yu, Fengbo; Gao, Haijun; Lei, Ting; Li, Peiwen; Liu, Pengfei; Zheng, Xu; Hu, Xitong; Chen, Yong; Jiang, Zhenfeng; Sayari, Arash J; Shen, Jia; Huang, Haiyan

    2015-01-01

    Glioblastomas multiforme (GBM) are the most frequently occurring malignant brain cancers. Treatment for GBM consists of surgical resection and subsequent adjuvant radiation therapy and chemotherapy. Despite this, GBM patient survival is limited to 12–15 months, and researchers are continually trying to develop improved therapy options. Insulin-like growth factor 2 mRNA-binding protein 2 (Imp2) is known to be upregulated in many cancers and is known to regulate the signaling activity of insulin-like growth factor 2 (IGF2). However, relatively little is known about its role in malignant development of GBM. In this study, we first found Imp2 is upregulated in GBM tissues by using clinical samples and public database search. Studies with loss and gain of Imp2 expression in in vitro GBM cell culture system demonstrated the role of Imp2 in promoting GBM cell proliferation, migration, invasion and epithelial-to-mesenchymal transition (EMT). Additionally, our results show that Imp2 regulates the activity of IGF2, which further activates PI3K/Akt signaling, thereby to promote GBM malignancy. Inhibition of Imp2 was also found to sensitize GBM to temozolomide treatment. These observations add to the current knowledge of GBM biology, and may prove useful in development of more effective GBM therapy. PMID:25719943

  12. 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

  13. 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.

  14. 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

  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. PI3K/Akt promotes feedforward mTORC2 activation through IKKα

    PubMed Central

    Dan, Han C.; Antonia, Ricardo J.; Baldwin, Albert S.

    2016-01-01

    The ser-thr Akt plays a critical role in the regulation of cell survival, cell growth and proliferation, as well as energy metabolism and is dysregulated in many cancers. The regulation of Akt activity depends on the phosphorylation at two sites: (i) Thr308 in the activation loop by phosphoinositide-dependent kinase-1 (PDK1) and (ii) Ser473 hydrophobic motif at the carboxyl terminus by a second activity termed PDK2, which is the mTORC2 complex composed of mTOR, rictor, and Sin1. Previously we demonstrated that IKKα, a component of the IKK complex that controls NF-κB activation, participates in the Akt-dependent regulation of mTORC1. Here we have explored a potential involvement of IKKα in controlling Akt activity and whether this may involve mTORC2. The experiments show that IKKα associates with mTORC2 in several cancer cells in a manner dependent on PI3K/Akt activity and that IKKα positively promotes Akt phosphorylation at Ser473 and at Thr308. Moreover, IKKα enhances mTORC2 kinase activity directed to Akt on Ser473 and Akt-mediated phosphorylation of FOXO3a and GSK3β, but not other Akt-associated targets such as TSC2 and PRAS40, indicating the existence of multiple mechanisms of Akt activation in cells. In addition, loss of IKKα suppresses growth factor-induced Akt activation associated with mTORC1 inhibition. These results indicate that IKKα serves as a feedforward regulator of mTORC2 and that IKKα could serve as a key therapeutic target to block mTORC2 and Akt activation in some cancers. PMID:27027448

  17. PI3K/Akt promotes feedforward mTORC2 activation through IKKα.

    PubMed

    Dan, Han C; Antonia, Ricardo J; Baldwin, Albert S

    2016-04-19

    The ser-thr Akt plays a critical role in the regulation of cell survival, cell growth and proliferation, as well as energy metabolism and is dysregulated in many cancers. The regulation of Akt activity depends on the phosphorylation at two sites: (i) Thr308 in the activation loop by phosphoinositide-dependent kinase-1 (PDK1) and (ii) Ser473 hydrophobic motif at the carboxyl terminus by a second activity termed PDK2, which is the mTORC2 complex composed of mTOR, rictor, and Sin1. Previously we demonstrated that IKKα, a component of the IKK complex that controls NF-κB activation, participates in the Akt-dependent regulation of mTORC1. Here we have explored a potential involvement of IKKα in controlling Akt activity and whether this may involve mTORC2. The experiments show that IKKα associates with mTORC2 in several cancer cells in a manner dependent on PI3K/Akt activity and that IKKα positively promotes Akt phosphorylation at Ser473 and at Thr308. Moreover, IKKα enhances mTORC2 kinase activity directed to Akt on Ser473 and Akt-mediated phosphorylation of FOXO3a and GSK3β, but not other Akt-associated targets such as TSC2 and PRAS40, indicating the existence of multiple mechanisms of Akt activation in cells. In addition, loss of IKKα suppresses growth factor-induced Akt activation associated with mTORC1 inhibition. These results indicate that IKKα serves as a feedforward regulator of mTORC2 and that IKKα could serve as a key therapeutic target to block mTORC2 and Akt activation in some cancers. PMID:27027448

  18. 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.

  19. 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.

  20. 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.

  1. Reversing HOXA9 Oncogene Activation by PI3K Inhibition: Epigenetic Mechanism and Prognostic Significance in Human Glioblastoma

    PubMed Central

    Costa, Bruno M.; Smith, Justin S.; Chen, Ying; Chen, Justin; Phillips, Heidi S.; Aldape, Kenneth D.; Zardo, Giuseppe; Nigro, Janice; James, C. David; Fridlyand, Jane; Reis, Rui M.; Costello, Joseph F.

    2010-01-01

    HOXA genes encode critical transcriptional regulators of embryonic development that have been implicated in cancer. In this study, we documented functional relevance and mechanism of activation of HOXA9 in glioblastoma (GBM), the most common malignant brain tumor. Expression of HOXA genes was investigated using RT-PCR in primary gliomas and glioblastoma cell lines and was validated in two sets of expression array data. In a subset of GBM, HOXA genes are aberrantly activated within confined chromosomal domains. Transcriptional activation of the HOXA cluster was reversible by a PI3K inhibitor through an epigenetic mechanism involving histone H3K27 trimethylation. Functional studies of HOXA9 showed its capacity to decrease apoptosis and increase cellular proliferation along with TRAIL resistance. Notably, aberrant expression of HOXA9 was independently predictive of shorter overall and progression-free survival in two GBM patient sets, and improved survival prediction by MGMT promoter methylation. Thus, HOXA9 activation is a novel, independent and negative prognostic marker in GBM that is reversible through a PI3K-associated epigenetic mechanism. Our findings suggest a transcriptional pathway through which PI3K activates oncogenic HOXA expression with implications for mTOR or PI3K targeted therapies. PMID:20068170

  2. 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.

  3. Activation of the PI3K/mTOR Pathway following PARP Inhibition in Small Cell Lung Cancer

    PubMed Central

    Mukherjee, Seema; Diao, Lixia; Tong, Pan; Stewart, C. Allison; Masrorpour, Fatemeh; Fan, YouHong; Nilsson, Monique; Shen, Yuqiao; Heymach, John V.; Wang, Jing; Byers, Lauren A.

    2016-01-01

    Small cell lung cancer (SCLC) is an aggressive malignancy with limited treatment options. We previously found that PARP is overexpressed in SCLC and that targeting PARP reduces cell line and tumor growth in preclinical models. However, SCLC cell lines with PI3K/mTOR pathway activation were relatively less sensitive to PARP inhibition. In this study, we investigated the proteomic changes in PI3K/mTOR and other pathways that occur following PAPR inhibition and/or knockdown in vitro and in vivo. Using reverse-phase protein array, we found the proteins most significantly upregulated following treatment with the PARP inhibitors olaparib and rucaparib were in the PI3K/mTOR pathway (p-mTOR, p-AKT, and pS6) (p≤0.02). Furthermore, amongst the most significantly down-regulated proteins were LKB1 and its targets AMPK and TSC, which negatively regulate the PI3K pathway (p≤0.042). Following PARP knockdown in cell lines, phosphorylated mTOR, AKT and S6 were elevated and LKB1 signaling was diminished. Global ATP concentrations increased following PARP inhibition (p≤0.02) leading us to hypothesize that the observed increased PI3K/mTOR pathway activation following PARP inhibition results from decreased ATP usage and a subsequent decrease in stress response signaling via LKB1. Based on these results, we then investigated whether co-targeting with a PARP and PI3K inhibitor (BKM-120) would work better than either single agent alone. A majority of SCLC cell lines were sensitive to BKM-120 at clinically achievable doses, and cMYC expression was the strongest biomarker of response. At clinically achievable doses of talazoparib (the most potent PARP inhibitor in SCLC clinical testing) and BKM-120, an additive effect was observed in vitro. When tested in two SCLC animal models, a greater than additive interaction was seen (p≤0.008). The data presented here suggest that combining PARP and PI3K inhibitors enhances the effect of either agent alone in preclinical models of SCLC

  4. 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

  5. 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.

  6. 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

  7. 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

  8. 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.

  9. Comparative analysis of MAPK and PI3K/AKT pathway activation and inhibition in human and canine melanoma.

    PubMed

    Fowles, J S; Denton, C L; Gustafson, D L

    2015-09-01

    The lack of advanced animal models of human cancers is considered a barrier to developing effective therapeutics. Canine and human melanomas are histologically disparate but show similar disease progression and response to therapies. The purpose of these studies was to compare human and canine melanoma tumours and cell lines regarding MAPK and PI3K/AKT signalling dysregulation, and response to select molecularly targeted agents. Pathway activation was investigated via microarray and mutational analysis. Growth inhibition and cell cycle effects were assessed for pathway inhibitors AZD6244 (MAPK) and rapamycin (PI3K/AKT) in human and canine melanoma cells. Human and canine melanoma share similar differential gene expression patterns within the MAPK and PI3K/AKT pathways. Constitutive pathway activation and similar sensitivity to AZD6244 and rapamycin was observed in human and canine cells. These results show that human and canine melanoma share activation and sensitivity to inhibition of cancer-related signalling pathways despite differences in activating mutations. PMID:23745794

  10. 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

  11. Design, synthesis, and biological activity of pyridopyrimidine scaffolds as novel PI3K/mTOR dual inhibitors.

    PubMed

    Saurat, Thibault; Buron, Frédéric; Rodrigues, Nuno; de Tauzia, Marie-Ludivine; Colliandre, Lionel; Bourg, Stéphane; Bonnet, Pascal; Guillaumet, Gérald; Akssira, Mohamed; Corlu, Anne; Guillouzo, Christiane; Berthier, Pauline; Rio, Pascale; Jourdan, Marie-Lise; Bénédetti, Hélène; Routier, Sylvain

    2014-02-13

    The design, synthesis, and screening of dual PI3K/mTOR inhibitors that gave nanomolar enzymatic and cellular activities on both targets with an acceptable kinase selectivity profile are described. A docking study was performed to understand the binding mode of the compounds and to explain the differences in biological activity. In addition, cellular effects of the best dual inhibitors were determined on six cancer cell lines and compared to those on a healthy diploid cell line for cellular cytotoxicity. Two compounds are highly potent on cancer cells in the submicromolar range without any toxicity on healthy cells. A more detailed analysis of the cellular effect of these PI3K/mTOR dual inhibitors demonstrated that they induce G1-phase cell cycle arrest in breast cancer cells and trigger apoptosis. These compounds show an interesting kinase profile as dual PI3K/mTOR tool compounds or as a chemical series for further optimization to progress into in vivo experiments.

  12. Intestinal trefoil factor activates the PI3K/Akt signaling pathway to protect gastric mucosal epithelium from damage.

    PubMed

    Sun, Zhaorui; Liu, Hongmei; Yang, Zhizhou; Shao, Danbing; Zhang, Wei; Ren, Yi; Sun, Baodi; Lin, Jinfeng; Xu, Min; Nie, Shinan

    2014-09-01

    Intestinal trefoil factor (ITF, also named as trefoil factor 3, TFF3) is a member of the TFF-domain peptide family, which plays an essential role in the regulation of cell survival, cell migration and maintains mucosal epithelial integrity in the gastrointestinal tract. However, the underlying mechanisms and associated molecules remain unclear. The aim of this study was to explore the protective effects of ITF on gastric mucosal epithelium injury and its possible molecular mechanisms of action. In the present study, we show that ITF was able to promote the proliferation and migration of GES-1 cells via a mechanism that involves the PI3K/Akt signaling pathway. Western blot results indicated that ITF induced a dose- and time-dependent increase in the Akt signaling pathway. ITF also plays an essential role in the restitution of GES-1 cell damage induced by lipopolysaccharide (LPS). LPS induced the apoptosis of GES-1 cells, decreased cell viability significantly (P<0.01) and led to epithelial tight junction damage, which is attenuated via ITF treatment. The protective effect of ITF on the integrity of GES-1 was abrogated by inhibition of the PI3K/Akt pathway. Taken together, our results demonstrate that ITF promotes the proliferation and migration of gastric mucosal epithelial cells and preserves gastric mucosal epithelial integrity after damage is mediated by activation of the PI3K/Akt signaling pathway. This study suggested that the PI3K/Akt pathway could act as a key intracellular pathway in the gastric mucosal epithelium that may serve as a therapeutic target to preserve epithelial integrity during injury.

  13. 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.

  14. 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

  15. 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

  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. Myrcia bella Leaf Extract Presents Hypoglycemic Activity via PI3k/Akt Insulin Signaling Pathway

    PubMed Central

    Vareda, Priscilla Maria Ponce; Saldanha, Luiz Leonardo; Camaforte, Nathalia Aparecida de Paula; Violato, Natalia Moretti; Dokkedal, Anne Lígia; Bosqueiro, José Roberto

    2014-01-01

    Species of Myrcia are used by indigenous people and in traditional communities in Brazil for the treatment of Diabetes mellitus. We investigated the hypoglycemic effect of the extract of leaves of Myrcia bella in diabetic mice. The chemical fingerprinting of the 70% EtOH extract characterized as main constituents flavonoid aglycones, flavonoid-O-glycosides, and acylated flavonoid-O-glycosides derivatives of quercetin and myricetin. Mice were treated with saline or extract of M. bella (300 or 600 mg/Kg b.w.) for 14 days. Body weight and water and food intake were measured every day. Fasting blood glucose was measured weekly. At the end of the treatment, blood insulin, triglycerides, total cholesterol, and protein were measured. Glycogen content and expression of proteins of the insulin signaling pathway were measured in liver. The treatment with 600 mg/Kg reduced the fasting blood glucose in diabetic mice of the 7th day as water and food intake and increased hepatic glycogen. Total cholesterol and triglycerides were reduced in diabetic treated mice. The treatment increased the expression of IRS-1, PI3-K, and AKT in the livers of diabetic treated mice. The results indicate that the extract of the leaves of Myrcia bella has hypoglycemic properties and possibly acts to regulate glucose uptake by the liver. PMID:24872834

  18. Notoginsenoside R1 ameliorates podocyte injury in rats with diabetic nephropathy by activating the PI3K/Akt signaling pathway

    PubMed Central

    Huang, Guodong; Lv, Jianzhen; Li, Tongyu; Huai, Guoli; Li, Xiang; Xiang, Shaowei; Wang, Longlong; Qin, Zhenlin; Pang, Jianli; Zou, Bingyu; Wang, Yi

    2016-01-01

    The present study was designed to examine the protective effect of notoginsenoside R1 (NR1) on podocytes in a rat model of streptozotocin (STZ)-induced diabetic nephropathy (DN), and to explore the mechanism responsible for NR1-induced renal protection. Diabetes was induced by a single injection of STZ, and NR1 was administered daily at a dose of 5 mg/kg (low dose), 10 mg/kg (medium) and 20 mg/kg (high) for 16 weeks in Sprague-Dawley rats. Blood glucose levels, body weight and proteinuria were measured every 4 weeks, starting on the day that the rats received NR1. Furthermore, on the day of sacrifice, blood, urine and kidneys were collected in order to assess renal function according to general parameters. Pathological staining was performed to evaluate the renal protective effect of NR1, and the expression of the key slit diaphragm proteins, namely neprhin, podocin and desmin, were evaluated. In addition, the serum levels of inflammatory cytokines [tumor necrosis factor-α (TNF-α), tumor growth factor-β1 (TGF-β1), interleukin (IL)-1 and IL-6] as well as an anti-inflammatory cytokine (IL-10) were assessed, and the apoptosis of podocytes was quantified. Finally, the phosphoinositide 3-kinase (PI3K)/Akt signaling pathway and the involvement of nuclear factor-κB (NF-κB) inactivation was further analyzed. In this study, NR1 improved renal function by ameliorating histological alterations, increasing the expression of nephrin and podocin, decreasing the expression of desmin, and inhibiting both the inflammatory response as well as the apoptosis of podocytes. Furthermore, NR1 treatment increased the phosphorylation of both PI3K (p85) and Akt, indicating that activation of the PI3K/Akt signaling pathway was involved. Moreover, NR1 treatment decreased the phosphorylation of NF-κB (p65), suggesting the downregulation of NF-κB. This is the first study to the best of our knowledge, to clearly demonstrate that NR1 treatment ameliorates podocyte injury by inhibiting both

  19. 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

  20. Modulation of Platelet Activation and Thrombus Formation Using a Pan-PI3K Inhibitor S14161

    PubMed Central

    Ren, Lijie; Liu, Xiaohui; Wang, Qi; He, Sudan; Wu, Qingyu; Hu, Hu; Mao, Xinliang; Zhu, Li

    2014-01-01

    The phosphatidylinositol 3–kinase (PI3K) signaling pathway is critical in modulating platelet functions. In the present study, we evaluated the effect of S14161, a recently identified pan-class I PI3K inhibitor, on platelet activation and thrombus formation. Results showed that S14161 inhibited human platelet aggregation induced by collagen, thrombin, U46619, and ADP in a dose-dependent manner. Flow cytometric studies showed that S14161 inhibited convulxin- or thrombin-induced P-selectin expression and fibrinogen binding of single platelet. S14161 also inhibited platelet spreading on fibrinogen and clot retraction, processes mediated by outside-in signaling. Using a microfluidic chamber we demonstrated that S14161 decreased platelet adhesion on collagen-coated surface by about 80%. Western blot showed that S14161 inhibited phosphorylation of Akt at both Ser473 and Thr308 sites, and GSK3β at Ser9 in response to collagen, thrombin, or U46619. Comparable studies showed that S14161 has a higher potential bioavailability than LY294002, a prototypical inhibitor of pan-class I PI3K. Finally, the effects of S14161 on thrombus formation in vivo were measured using a ferric chloride-induced carotid artery injury model in mice. The intraperitoneal injection of S14161 (2 mg/kg) to male C57BL/6 mice significantly extended the first occlusion time (5.05±0.99 min, n = 9) compared to the vehicle controls (3.72±0.95 min, n = 8) (P<0.05), but did not prolong the bleeding time (P>0.05). Taken together, our data showed that S14161 inhibits platelet activation and thrombus formation without significant bleeding tendency and toxicity, and considering its potential higher bioavailability, it may be developed as a novel therapeutic agent for the prevention of thrombotic disorders. PMID:25115838

  1. Dimethyloxaloylglycine Promotes the Angiogenic Activity of Mesenchymal Stem Cells Derived from iPSCs via Activation of the PI3K/Akt Pathway for Bone Regeneration

    PubMed Central

    Zhang, Jieyuan; Guan, Junjie; Qi, Xin; Ding, Hao; Yuan, Hong; Xie, Zongping; Chen, Chunyuan; Li, Xiaolin; Zhang, Changqing; Huang, Yigang

    2016-01-01

    The vascularization of tissue-engineered bone is a prerequisite step for the successful repair of bone defects. Hypoxia inducible factor-1α (HIF-1α) plays an essential role in angiogenesis-osteogenesis coupling during bone regeneration and can activate the expression of angiogenic factors in mesenchymal stem cells (MSCs). Dimethyloxaloylglycine (DMOG) is an angiogenic small molecule that can inhibit prolyl hydroxylase (PHD) enzymes and thus regulate the stability of HIF-1α in cells at normal oxygen tension. Human induced pluripotent stem cell-derived MSCs (hiPSC-MSCs) are promising alternatives for stem cell therapy. In this study, we evaluated the effect of DMOG on promoting hiPSC-MSCs angiogenesis in tissue-engineered bone and simultaneously explored the underlying mechanisms in vitro. The effectiveness of DMOG in improving the expression of HIF-1α and its downstream angiogenic genes in hiPSC-MSCs demonstrated that DMOG significantly enhanced the gene and protein expression profiles of angiogenic-related factors in hiPSC-MSCs by sustaining the expression of HIF-1α. Further analysis showed that DMOG-stimulated hiPSC-MSCs angiogenesis was associated with the phosphorylation of protein kinase B (Akt) and with an increase in VEGF production. The effects could be blocked by the addition of the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002. In a critical-sized calvarial defect model in rats, DMOG-treated hiPSC-MSCs showed markedly improved angiogenic capacity in the tissue-engineered bone, leading to bone regeneration. Collectively, the results indicate that DMOG, via activation of the PI3K/Akt pathway, promotes the angiogenesis of hiPSC-MSCs in tissue-engineered bone for bone defect repair and that DMOG-treated hiPSC-MSCs can be exploited as a potential therapeutic tool in bone regeneration. PMID:27194942

  2. 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.

  3. Isorhamnetin Attenuates Atherosclerosis by Inhibiting Macrophage Apoptosis via PI3K/AKT Activation and HO-1 Induction

    PubMed Central

    Luo, Yun; Sun, Guibo; Dong, Xi; Wang, Min; Qin, Meng; Yu, Yingli; Sun, Xiaobo

    2015-01-01

    Background and Purpose Isorhamnetin (Iso) is a flavonoid compound extracted from the Chinese herb Hippophae rhamnoides L. Previous studies have revealed its anti-cancer, anti-inflammatory, and anti-oxidant activities. This study investigated the ability of Iso to inhibit oxidized low-density lipoprotein (ox-LDL)-induced cell apoptosis in THP-1-derived macrophages. The effects of Iso on atherosclerosis in vivo were also evaluated in apolipoprotein E knockout (ApoE-/-) mice fed a high fat diet. Methods and Results Iso showed significant inhibitory effects on ox-LDL-induced THP-1-derived macrophage injuries via decreasing reactive oxygen species levels, lipid deposition, and caspase-3 activation, restoring mitochondrial membrane potential, reducing the number of terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL)-positive cells, and regulating apoptosis-related proteins. We also determined the protective effects of Iso by PI3K/AKT activation and HO-1 induction. Iso reduced the atherosclerotic plaque size in vivo in ApoE-/- mice as assessed by oil red O, Sudan IV staining, and CD68-positive cells, and reduced macrophage apoptosis as assessed by caspase-3 and TUNEL assays in lesions. Conclusion In conclusion, our results show that Iso inhibited atherosclerotic plaque development in ApoE-/- mice by PI3K/AKT activation and HO-1 induction. PMID:25799286

  4. Tetramethylpyrazine attenuates TNF-α-induced iNOS expression in human endothelial cells: Involvement of Syk-mediated activation of PI3K-IKK-IκB signaling pathways

    SciTech Connect

    Zheng, Zhen; Li, Zhiliang; Chen, Song; Pan, Jieyi; Ma, Xiaochun

    2013-08-15

    Endothelial cells produce nitric oxide (NO) by activation of constitutive nitric oxide synthase (NOS) and transcription of inducible NO synthase (iNOS). We explored the effect of tetramethylpyrazine (TMP), a compound derived from chuanxiong, on tumor necrosis factor (TNF)-α-induced iNOS in human umbilical vein endothelial cells (HUVECs) and explored the signal pathways involved by using RT-PCR and Western blot. TMP suppressed TNF-α-induced expression of iNOS by inhibiting IκB kinase (IKK) phosphorylation, IκB degradation and nuclear factor κB (NF-κB) nuclear translocation, which were required for NO gene transcription. Exposure to wortmannin abrogated IKK/IκB/NF-κB-mediated iNOS expression, suggesting activation of such a signal pathway might be phosphoinositide-3-kinase (PI3K) dependent. Spleen tyrosine kinase (Syk) inhibitor piceatannol significantly inhibited NO production. Furthermore, piceatannol obviously suppressed TNF-α-induced IκB phosphorylation and the downstream NF-κB activation, suggesting that Syk is an upstream key regulator in the activation of PI3K/IKK/IκB-mediated signaling. TMP significantly inhibited TNF-α-induced phosphorylation of Syk and PI3K. Our data indicate that TMP might repress iNOS expression, at least in part, through its inhibitory effect of Syk-mediated PI3K phosphorylation in TNF-α-stimulated HUVECs. -- Highlights: •TMP suppressed TNF-α-induced expression of iNOS by inhibiting IKK/IκB/NF-κB pathway. •PI3K inhibitor wortmannin abrogated IKK/IκB/NF-κB-mediated iNOS expression. •Syk inhibitor piceatannol repressed PI3K/IKK/IκB mediated NO production. •Syk is an upstream regulator in the activation of PI3K/IKK/IκB-mediated signaling. •TMP might repress iNOS expression through Syk-mediated PI3K pathway.

  5. 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

  6. {delta}-Opioid receptor-stimulated Akt signaling in neuroblastoma x glioma (NG108-15) hybrid cells involves receptor tyrosine kinase-mediated PI3K activation

    SciTech Connect

    Heiss, Anika; Ammer, Hermann; Eisinger, Daniela A.

    2009-07-15

    {delta}-Opioid receptor (DOR) agonists possess cytoprotective properties, an effect associated with activation of the 'pro-survival' kinase Akt. Here we delineate the signal transduction pathway by which opioids induce Akt activation in neuroblastoma x glioma (NG108-15) hybrid cells. Exposure of the cells to both [D-Pen{sup 2,5}]enkephalin and etorphine resulted in a time- and dose-dependent increase in Akt activity, as measured by means of an activation-specific antibody recognizing phosphoserine-473. DOR-mediated Akt signaling is blocked by the opioid antagonist naloxone and involves inhibitory G{sub i/o} proteins, because pre-treatment with pertussis toxin, but not over-expression of the G{sub q/11} scavengers EBP50 and GRK2-K220R, prevented this effect. Further studies with Wortmannin and LY294002 revealed that phophoinositol-3-kinase (PI3K) plays a central role in opioid-induced Akt activation. Opioids stimulate Akt activity through transactivation of receptor tyrosine kinases (RTK), because pre-treatment of the cells with inhibitors for neurotrophin receptor tyrosine kinases (AG879) and the insulin-like growth factor receptor IGF-1 (AG1024), but not over-expression of the G{beta}{gamma} scavenger phosducin, abolished this effect. Activated Akt translocates to the nuclear membrane, where it promotes GSK3 phosphorylation and prevents caspase-3 cleavage, two key events mediating inhibition of cell apoptosis and enhancement of cell survival. Taken together, these results demonstrate that in NG108-15 hybrid cells DOR agonists possess cytoprotective properties mediated by activation of the RTK/PI3K/Akt signaling pathway.

  7. Neuritogenic Monoglyceride Derived from the Constituent of a Marine Fish for Activating the PI3K/ERK/CREB Signalling Pathways in PC12 Cells

    PubMed Central

    Yang, Wei; Luo, Yan; Tang, Ruiqi; Zhang, Hui; Ye, Ying; Xiang, Lan; Qi, Jianhua

    2013-01-01

    A neuritogenic monoglyceride, 1-O-(myristoyl) glycerol (MG), was isolated from the head of Ilisha elongate using a PC12 cell bioassay system, and its chemical structure was elucidated using spectroscopic methods. MG significantly induced 42% of the neurite outgrowth of PC12 cells at a concentration of 10 μM. To study the structure-activity relationships of MG, a series of monoglycerides was designed and synthesised. Bioassay results indicated that the alkyl chain length plays a key role in the neuritogenic activity of the monoglycerides. The groups that link the propane-1,2-diol and alkyl chain were also investigated. An ester linkage, rather than an amido one, was found to be optimal for neuritogenic activity. Therefore, 1-O-(stearoyl) glycerol (SG), which induces 57% of the neurite outgrowth of PC12 cells at 10 μM, was determined to be a lead compound for neuritogenic activity. We then investigated the mechanism of action of neurite outgrowth induced by SG on PC12 cells using protein specific inhibitors and Western blot analysis. The mitogen-activated kinase/ERK kinase (MEK) inhibitor U0126 and the phosphatidylinositol-3 kinase (PI3K) inhibitor LY294002 significantly decreased neurite outgrowth. At the same time, SG increased phosphorylation of CREB in protein level. Thus, SG-induced neuritogenic activity depends on the activation of the extracellular-regulated protein kinase (ERK), cAMP responsive element-binding protein (CREB) and PI3K signalling pathways in PC12 cells. PMID:24351811

  8. Dally Proteoglycan Mediates the Autonomous and Nonautonomous Effects on Tissue Growth Caused by Activation of the PI3K and TOR Pathways

    PubMed Central

    Ferreira, Ana; Milán, Marco

    2015-01-01

    How cells acquiring mutations in tumor suppressor genes outcompete neighboring wild-type cells is poorly understood. The phosphatidylinositol 3-kinase (PI3K)–phosphatase with tensin homology (PTEN) and tuberous sclerosis complex (TSC)-target of rapamycin (TOR) pathways are frequently activated in human cancer, and this activation is often causative of tumorigenesis. We utilized the Gal4-UAS system in Drosophila imaginal primordia, highly proliferative and growing tissues, to analyze the impact of restricted activation of these pathways on neighboring wild-type cell populations. Activation of these pathways leads to an autonomous induction of tissue overgrowth and to a remarkable nonautonomous reduction in growth and proliferation rates of adjacent cell populations. This nonautonomous response occurs independently of where these pathways are activated, is functional all throughout development, takes place across compartments, and is distinct from cell competition. The observed autonomous and nonautonomous effects on tissue growth rely on the up-regulation of the proteoglycan Dally, a major element involved in modulating the spreading, stability, and activity of the growth promoting Decapentaplegic (Dpp)/transforming growth factor β(TGF-β) signaling molecule. Our findings indicate that a reduction in the amount of available growth factors contributes to the outcompetition of wild-type cells by overgrowing cell populations. During normal development, the PI3K/PTEN and TSC/TOR pathways play a major role in sensing nutrient availability and modulating the final size of any developing organ. We present evidence that Dally also contributes to integrating nutrient sensing and organ scaling, the fitting of pattern to size. PMID:26313758

  9. Dally Proteoglycan Mediates the Autonomous and Nonautonomous Effects on Tissue Growth Caused by Activation of the PI3K and TOR Pathways.

    PubMed

    Ferreira, Ana; Milán, Marco

    2015-08-01

    How cells acquiring mutations in tumor suppressor genes outcompete neighboring wild-type cells is poorly understood. The phosphatidylinositol 3-kinase (PI3K)-phosphatase with tensin homology (PTEN) and tuberous sclerosis complex (TSC)-target of rapamycin (TOR) pathways are frequently activated in human cancer, and this activation is often causative of tumorigenesis. We utilized the Gal4-UAS system in Drosophila imaginal primordia, highly proliferative and growing tissues, to analyze the impact of restricted activation of these pathways on neighboring wild-type cell populations. Activation of these pathways leads to an autonomous induction of tissue overgrowth and to a remarkable nonautonomous reduction in growth and proliferation rates of adjacent cell populations. This nonautonomous response occurs independently of where these pathways are activated, is functional all throughout development, takes place across compartments, and is distinct from cell competition. The observed autonomous and nonautonomous effects on tissue growth rely on the up-regulation of the proteoglycan Dally, a major element involved in modulating the spreading, stability, and activity of the growth promoting Decapentaplegic (Dpp)/transforming growth factor β(TGF-β) signaling molecule. Our findings indicate that a reduction in the amount of available growth factors contributes to the outcompetition of wild-type cells by overgrowing cell populations. During normal development, the PI3K/PTEN and TSC/TOR pathways play a major role in sensing nutrient availability and modulating the final size of any developing organ. We present evidence that Dally also contributes to integrating nutrient sensing and organ scaling, the fitting of pattern to size.

  10. Activation of transient receptor potential vanilloid 4 induces apoptosis in hippocampus through downregulating PI3K/Akt and upregulating p38 MAPK signaling pathways

    PubMed Central

    Jie, P; Hong, Z; Tian, Y; Li, Y; Lin, L; Zhou, L; Du, Y; Chen, L; Chen, L

    2015-01-01

    Transient receptor potential vanilloid 4 (TRPV4) is a calcium-permeable cation channel that is sensitive to cell swelling, arachidonic acid and its metabolites, epoxyeicosatrienoic acids, which are associated with cerebral ischemia. The activation of TRPV4 induces cytotoxicity in many types of cells, accompanied by an increase in the intracellular free calcium concentration. TRPV4 activation modulates the mitogen-activated protein kinase (MAPK) and phosphatidyl inositol 3 kinase (PI3K)/ protein kinase B (Akt) signaling pathways that regulate cell death and survival. Herein, we examined TRPV4-induced neuronal apoptosis by intracerebroventricular (ICV) injection of a TRPV4 agonist (GSK1016790A) and assessed its involvement in cerebral ischemic injury. ICV injection of GSK1016790A dose-dependently induced apoptosis in the mouse hippocampi (GSK-injected mice). The protein level of phosphorylated p38 MAPK (p-p38 MAPK) was markedly increased and that of phosphorylated c-Jun N-terminal protein kinase (p-JNK) was virtually unchanged. TRPV4 activation also decreased Bcl-2/Bax protein ratio and increased the cleaved caspase-3 protein level, and these effects were blocked by a PI3K agonist and a p38 MAPK antagonist, but were unaffected by a JNK antagonist. ICV injection of the TRPV4 antagonist HC-067047 reduced brain infarction after reperfusion for 48 h in mice with middle cerebral artery occlusion (MCAO). In addition, HC-067047 treatment attenuated the decrease in the phosphorylated Akt protein level and the increase in p-p38 MAPK protein level at 48 h after MCAO, while the increase in p-JNK protein level remained unchanged. Finally, the decreased Bcl-2/Bax protein ratio and the increased cleaved caspase-3 protein level at 48 h after MCAO were markedly attenuated by HC-067047. We conclude that activation of TRPV4 induces apoptosis by downregulating PI3K/Akt and upregulating p38 MAPK signaling pathways, which is involved in cerebral ischemic injury. PMID:26043075

  11. Astragaloside IV inhibits doxorubicin-induced cardiomyocyte apoptosis mediated by mitochondrial apoptotic pathway via activating the PI3K/Akt pathway.

    PubMed

    Jia, Yuanyuan; Zuo, Daiying; Li, Zengqiang; Liu, Hanmo; Dai, Zhengning; Cai, Jiayi; Pang, Lili; Wu, Yingliang

    2014-01-01

    Doxorubicin (DOX) is a widely used antitumor drug whose application is seriously limited by its cardiotoxicity. Mitochondria-mediated cardiomyocyte apoptosis plays a critical role in DOX-induced cardiotoxicity (DIC). The aim of the present study was to investigate the protective effect of astragaloside IV (3-O-beta-D-xylopyranosyl-6-O-beta-D-glucopyranosyl-cycloastragenol, AS-IV), a pure saponin isolated from Astragalus membranaceus, against DOX-induced cardiomyocyte apoptosis in primary cultured neonatal rat cardiomyocytes. Immunocytochemistry and Microculture Tetrazolium (MTT) assays showed that AS-IV significantly reduced DOX-induced cardiomyocyte loss. Additionally, AS-IV markedly ameliorated DOX-caused cardiomyocyte dysfunction via restoring the beating cell ratio and beating rate in cardiomyocytes. Furthermore, AS-IV substantially reduced the mitochondrial reactive oxygen species (ROS) production and lactate dehydrogenase (LDH), creatine kinase-MB isoenzyme (CK-MB) and cytochrome c (CytC) release, and restored the reduced ATP level, succinate dehydrogenase (SDH) and ATP synthase activities induced by DOX, suggesting that AS-IV significantly attenuated DOX-induced mitochondrial damage and dysfunction. It was further observed that DOX-induced cardiomyocyte apoptosis, as qualitatively evaluated by Hoechst 33258 staining and accurately quantified by flow cytometry, was markedly inhibited by AS-IV. Western blot analysis manifested that AS-IV significantly inhibited the activation of mitochondrial apoptotic pathway (MAP) via inducing the phosphorylation of Akt and Bad. Furthermore, phosphatidylinositol 3-kinase (PI3K) inhibitor 2-(4-morpholinyl)-8-phenyl-1(4H)-benzopyran-4-one hydrochloride (LY294002) remarkably inhibited the anti-apoptotic effect of AS-IV. Moreover, AS-IV didn't compromise the antitumor activity of DOX. Taken together, our findings indicate that AS-IV ameliorates DIC, and this beneficial effect appears to be dependent on the activation of the PI3K

  12. Galectin-1 induces hepatocellular carcinoma EMT and sorafenib resistance by activating FAK/PI3K/AKT signaling

    PubMed Central

    Zhang, P-F; Li, K-S; Shen, Y-h; Gao, P-T; Dong, Z-R; Cai, J-B; Zhang, C; Huang, X-Y; Tian, M-X; Hu, Z-Q; Gao, D-M; Fan, J; Ke, A-W; Shi, G-M

    2016-01-01

    Galectin-1 (Gal-1) is involved in several pathological activities associated with tumor progression and chemoresistance, however, the role and molecular mechanism of Gal-1 activity in hepatocellular carcinoma (HCC) epithelial–mesenchymal transition (EMT) and sorafenib resistance remain enigmatic. In the present study, forced Gal-1 expression promoted HCC progression and sorafenib resistance. Gal-1 elevated αvβ3-integrin expression, leading to AKT activation. Moreover, Gal-1 overexpression induced HCC cell EMT via PI3K/AKT cascade activation. Clinically, our data revealed that Gal-1 overexpression is correlated with poor HCC survival outcomes and sorafenib response. These data suggest that Gal-1 may be a potential therapeutic target for HCC and a biomarker for predicting response to sorafenib treatment. PMID:27100895

  13. Galectin-1 induces hepatocellular carcinoma EMT and sorafenib resistance by activating FAK/PI3K/AKT signaling.

    PubMed

    Zhang, P-F; Li, K-S; Shen, Y-H; Gao, P-T; Dong, Z-R; Cai, J-B; Zhang, C; Huang, X-Y; Tian, M-X; Hu, Z-Q; Gao, D-M; Fan, J; Ke, A-W; Shi, G-M

    2016-01-01

    Galectin-1 (Gal-1) is involved in several pathological activities associated with tumor progression and chemoresistance, however, the role and molecular mechanism of Gal-1 activity in hepatocellular carcinoma (HCC) epithelial-mesenchymal transition (EMT) and sorafenib resistance remain enigmatic. In the present study, forced Gal-1 expression promoted HCC progression and sorafenib resistance. Gal-1 elevated αvβ3-integrin expression, leading to AKT activation. Moreover, Gal-1 overexpression induced HCC cell EMT via PI3K/AKT cascade activation. Clinically, our data revealed that Gal-1 overexpression is correlated with poor HCC survival outcomes and sorafenib response. These data suggest that Gal-1 may be a potential therapeutic target for HCC and a biomarker for predicting response to sorafenib treatment. PMID:27100895

  14. Activation of PI3K/Akt/mTOR signaling in the tumor stroma drives endocrine therapy-dependent breast tumor regression

    PubMed Central

    Polo, María Laura; Riggio, Marina; May, María; Rodríguez, María Jimena; Perrone, María Cecilia; Stallings-Mann, Melody; Kaen, Diego; Frost, Marlene; Goetz, Matthew; Boughey, Judy; Lanari, Claudia; Radisky, Derek; Novaro, Virginia

    2015-01-01

    Improved efficacy of neoadjuvant endocrine-targeting therapies in luminal breast carcinomas could be achieved with optimal use of pathway targeting agents. In a mouse model of ductal breast carcinoma we identify a tumor regressive stromal reaction that is induced by neoadjuvant endocrine therapy. This reparative reaction is characterized by tumor neovascularization accompanied by infiltration of immune cells and carcinoma-associated fibroblasts that stain for phosphorylated ribosomal protein S6 (pS6), downstream the PI3K/Akt/mTOR pathway. While tumor variants with higher PI3K/Akt/mTOR activity respond well to a combination of endocrine and PI3K/Akt/mTOR inhibitors, tumor variants with lower PI3K/Akt/mTOR activity respond more poorly to the combination therapy than to the endocrine therapy alone, associated with inhibition of stromal pS6 and the reparative reaction. In human breast cancer xenografts we confirm that such differential sensitivity to therapy is primarily determined by the level of PI3K/Akt/mTOR in tumor cells. We further show that the clinical response of breast cancer patients undergoing neoadjuvant endocrine therapy is associated with the reparative stromal reaction. We conclude that tumor level and localization of pS6 are associated with therapeutic response in breast cancer and represent biomarkers to distinguish which tumors will benefit from the incorporation of PI3K/Akt/mTOR inhibitors with neoadjuvant endocrine therapy. PMID:26098779

  15. Astaxanthin protects ARPE-19 cells from oxidative stress via upregulation of Nrf2-regulated phase II enzymes through activation of PI3K/Akt

    PubMed Central

    Li, Zhongrui; Dong, Xin; Liu, Hongling; Chen, Xi; Shi, Huanqi; Fan, Yan; Hou, Dingshan

    2013-01-01

    Purpose Oxidative stress on retinal pigment epithelial (RPE) cells is thought to play a crucial role in the development and progression of age-related macular degeneration. Astaxanthin (AST) is a carotenoid that shows significant antioxidant properties. This study was designed to investigate the protective effect of AST on ARPE-19 cells against oxidative stress and the possible underlying mechanism. Methods ARPE-19 cells exposed to different doses of H2O2 were incubated with various concentrations of AST and cell viability subsequently detected with the (4-[3-[4-iodophenyl]-2–4(4-nitrophenyl)-2H-5- tetrazolio-1,3-benzene disulfonate]; WST-1) assay. The apoptosis rate and intracellular levels of reactive oxygen species (ROS) were measured with flow cytometry. NAD(P)H quinine oxidoreductase 1 (NQO1), hemeoxygenase-1 (HO-1), glutamate-cysteine ligase modifier subunit (GCLM), and glutamate-cysteine ligase catalytic subunit (GCLC) expression were examined with real-time PCR and western blotting. The nuclear localization of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) protein and the expression levels of cleaved caspase-3 and protein kinase B proteins were evaluated with western blotting. Results AST clearly reduced H2O2-induced cell viability loss, cell apoptosis, and intracellular generation of ROS. Furthermore, treatment with AST activated the Nrf2-ARE pathway by inducing Nrf2 nuclear localization. Consequently, Phase II enzymes NQO1, HO-1, GCLM, and GCLC mRNA and proteins were increased. AST inhibited expression of H2O2-induced cleaved caspase-3 protein. Activation of the phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) pathway was involved in the protective effect of AST on the ARPE-19 cells. Conclusions AST protected ARPE-19 cells against H2O2-induced oxidative stress via Nrf2-mediated upregulation of the expression of Phase II enzymes involving the PI3K/Akt pathway. PMID:23901249

  16. 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

  17. Romidepsin (FK228) and its analogs directly inhibit phosphatidylinositol 3-kinase activity and potently induce apoptosis as histone deacetylase/phosphatidylinositol 3-kinase dual inhibitors.

    PubMed

    Saijo, Ken; Katoh, Tadashi; Shimodaira, Hideki; Oda, Akifumi; Takahashi, Ohgi; Ishioka, Chikashi

    2012-11-01

    Activation of phosphatidylinositol 3-kinase (PI3K) signaling is involved in carcinogenesis and cancer progression. The PI3K inhibitors are considered candidate drugs for cancer treatment. Here, we describe a drug screening system for novel PI3K inhibitors using Saccharomyces cerevisiae strains with deleterious mutations in the ATP-binding cassette transporter genes, because wild-type S. cerevisiae uses drug efflux pumps for reducing intracellular drug concentrations. By screening the chemical library of the Screening Committee of Anticancer Drugs, we identified the histone deacetylase (HDAC) inhibitor romidepsin (FK228) and its novel analogs. In vitro PI3K activity assays confirmed that these compounds directly inhibit PI3K activity at μM-range concentrations. FK-A5 analog was the most potent inhibitor. Western blotting revealed that these compounds inhibit phosphorylation of protein kinase B and downstream signaling components. Molecular modeling of the PI3K-FK228 complex indicated that FK228 binds to the ATP-binding pocket of PI3K. At μM-range concentrations, FK228 and FK-A5 show potent cytotoxicity, inducing apoptosis even in HDAC inhibitor-resistant cells. Furthermore, HDAC/PI3K dual inhibition by FK228 and FK-A5 at μM-range concentrations potentiates the apoptosis induction, mimicking the effect of combining specific HDAC and PI3K inhibitors. In this study, we showed that FK228 and its analogs directly inhibit PI3K activity and induce apoptosis at μM-range concentrations, similar to HDAC/PI3K dual inhibition. In future, optimizing the potency of FK228 and its analogs against PI3K may contribute to the development of novel HDAC/PI3K dual inhibitors for cancer treatment.

  18. Notoginsenoside R1 ameliorates podocyte injury in rats with diabetic nephropathy by activating the PI3K/Akt signaling pathway.

    PubMed

    Huang, Guodong; Lv, Jianzhen; Li, Tongyu; Huai, Guoli; Li, Xiang; Xiang, Shaowei; Wang, Longlong; Qin, Zhenlin; Pang, Jianli; Zou, Bingyu; Wang, Yi

    2016-10-01

    The present study was designed to examine the protective effect of notoginsenoside R1 (NR1) on podocytes in a rat model of streptozotocin (STZ)‑induced diabetic nephropathy (DN), and to explore the mechanism responsible for NR1-induced renal protection. Diabetes was induced by a single injection of STZ, and NR1 was administered daily at a dose of 5 mg/kg (low dose), 10 mg/kg (medium) and 20 mg/kg (high) for 16 weeks in Sprague-Dawley rats. Blood glucose levels, body weight and proteinuria were measured every 4 weeks, starting on the day that the rats received NR1. Furthermore, on the day of sacrifice, blood, urine and kidneys were collected in order to assess renal function according to general parameters. Pathological staining was performed to evaluate the renal protective effect of NR1, and the expression of the key slit diaphragm proteins, namely neprhin, podocin and desmin, were evaluated. In addition, the serum levels of inflammatory cytokines [tumor necrosis factor-α (TNF-α), tumor growth factor-β1 (TGF-β1), interleukin (IL)-1 and IL-6] as well as an anti-inflammatory cytokine (IL-10) were assessed, and the apoptosis of podocytes was quantified. Finally, the phosphoinositide 3-kinase (PI3K)/Akt signaling pathway and the involvement of nuclear factor-κB (NF-κB) inactivation was further analyzed. In this study, NR1 improved renal function by ameliorating histological alterations, increasing the expression of nephrin and podocin, decreasing the expression of desmin, and inhibiting both the inflammatory response as well as the apoptosis of podocytes. Furthermore, NR1 treatment increased the phosphorylation of both PI3K (p85) and Akt, indicating that activation of the PI3K/Akt signaling pathway was involved. Moreover, NR1 treatment decreased the phosphorylation of NF-κB (p65), suggesting the downregulation of NF-κB. This is the first study to the best of our knowledge, to clearly demonstrate that NR1 treatment ameliorates podocyte injury

  19. 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.

  20. 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

  1. Apelin-36, a potent peptide, protects against ischemic brain injury by activating the PI3K/Akt pathway.

    PubMed

    Gu, Qin; Zhai, Lijing; Feng, Xing; Chen, Jing; Miao, Zhigang; Ren, Liyan; Qian, Xuanchen; Yu, Jian; Li, Yan; Xu, Xingshun; Liu, Chun-Feng

    2013-11-01

    Apelin is an endogenous ligand of G protein-coupled receptor-apelin and angiotensin-1-like receptor (APJ). The biological effects of apelin-APJ system are reported in multiple systems including cardiovascular, endocrinal, and gastrointestinal system. Previous studies had shown that apelin-13 is a potential protective agent on cardiac ischemia; however, the role of apelin in the central nervous system remained unknown. In this study, we investigated therapeutic effects of apelin-36, a long form of apelin, in ischemic brain injury models. We found that apelin-36 reduced cerebral infarct volume in the middle cerebral artery occlusion (MCAO) model and the neonatal hypoxic/ischemic (H/I) injury model. Apelin-36 improved neurological deficits in the MCAO model and promoted long-term functional recovery after H/I brain injury. We further explored the protective mechanisms of apelin-36 on H/I brain injury. We clearly demonstrated that apelin-36 significantly reduced the levels of cleaved caspase-3 and Bax, two well-established apoptotic markers after H/I injury, indicating the anti-apoptotic activity of apelin-36 in ischemic injury. Since apelin-36 increased the level of phosphorylated Akt after H/I injury, we treated neonates with a specific PI3K inhibitor LY294002. We found that LY294002 decreased the phosphorylated Akt level and attenuated protective effects of apelin-36 on apoptosis. These suggested that the PI3K/Akt pathway was at least in part involved in the anti-apoptotic mechanisms of apelin-36. Our findings demonstrated that apelin-36 was a promising therapeutic agent on the treatment of ischemic brain injury.

  2. 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

  3. Polarization of PI3K Activity Initiated by Ooplasmic Segregation Guides Nuclear Migration in the Mesendoderm.

    PubMed

    Takatori, Naohito; Oonuma, Kouhei; Nishida, Hiroki; Saiga, Hidetoshi

    2015-11-01

    Asymmetric localization of RNA is a widely observed mechanism of cell polarization. Using embryos of the ascidian, Halocynthia roretzi, we previously showed that mesoderm and endoderm fates are separated by localization of mRNA encoding a transcription factor, Not, to the future mesoderm-side cytoplasm of the mesendoderm cell through asymmetric positioning of the nucleus. Here, we investigated the mechanism that defines the direction of the nuclear migration. We show that localization of PtdIns(3,4,5)P3 to the future mesoderm region determines the direction of nuclear migration. Localization of PtdIns(3,4,5)P3 was dependent on the localization of PI3Kα to the future mesoderm region. PI3Kα was first localized at the 1-cell stage by the ooplasmic movement. Activity of localized PI3Kα at the 4-cell stage was required for the localization of PI3Kα up to the nuclear migration. Our results provide the scaffold for understanding the chain of causality leading to the separation of germ layer fates. PMID:26555053

  4. Antitumor Activity of Tenacissoside H on Esophageal Cancer through Arresting Cell Cycle and Regulating PI3K/Akt-NF-κB Transduction Cascade

    PubMed Central

    Jia, Yong-sen; Hu, Xue-qin; Gabriella, Hegyi; Qin, Li-juan; Meggyeshazi, Nora

    2015-01-01

    Objective. The purpose of the study was to elucidate the molecular mechanism of tenacissoside H (TDH) inhibiting esophageal carcinoma infiltration and proliferation. Methods. In vitro, EC9706 cells were treated with TDH. Cells proliferation and cell cycle were assayed. PI3K and NF-κB mRNAs expression were determined by real time PCR. In vivo, model of nude mice with tumor was established. Mice were treated with TDH. Inhibition ratio of tumor volume was calculated. PCNA expression was examined. Protein expression in PI3K/Akt-NF-κB signaling pathway was determined. Results. In vitro, TDH significantly inhibited cells proliferation in a time-and-dose-dependent manner. TDH arrested the cell cycle in S phase and significantly inhibited PI3K and NF-κB mRNA expression, compared with blank controlled group (P < 0.05). In vivo, TDH strongly inhibits tumor growth and volume. PCNA expression was significantly decreased after treatment of TDH. TDH downregulated proteins expression in PI3K/Akt-NF-κB transduction cascade (P < 0.05). Conclusion. TDH inhibited esophageal carcinoma infiltration and proliferation both in vitro and in vivo. The anticancer activity has relation to arresting the cell cycle at the S phase, inhibited the PCNA expression of transplanted tumors in nude mice, and regulated the protein expression in the PI3K/Akt-NF-κB transduction cascade. PMID:26495015

  5. The nuclear protein Sam68 is redistributed to the cytoplasm and is involved in PI3K/Akt activation during EV71 infection.

    PubMed

    Zhang, Hua; Cong, Haolong; Song, Lei; Tien, Po

    2014-02-13

    Nuclear proteins can be triggered to be redistributed to the cytoplasm to assist with EV71 virus replication. This process is frequently involved in cellular signal transduction upon virus infection. In this study, we have demonstrated that a new nuclear protein, 68-kDa Src-associated in mitosis protein (Sam68), was translocated to the cytoplasm and was co-localized with EV71 during virus infection. Confocal microscopy and subcellular fractionation assay confirmed that virus 3C protease triggered the redistribution of Sam68 to the cytoplasm. Knockdown of Sam68 expression using ShRNA significantly inhibited virus replication, suggesting that Sam68 may be a host factor involved in EV71 life cycle. In addition, EV71-induced Akt phosphorylation involved a PI3K-dependent mechanism. Sam68 is known to be an upstream regulator of PI3K and our immunoprecipitation studies confirmed that Sam68 interacted directly with the p85 regulatory subunit of PI3K and mediated PI3K/Akt activation during EV71 infection. On the contrary, silencing of Sam68 dramatically abrogated Akt phosphorylation. These data, plus the fact that Sam68 is known to be a signaling adaptor protein, indicated that Sam68 is a signal molecule with a functional role in the PI3K/Akt signal pathway during EV71 infection.

  6. Src kinase and Syk activation initiate PI3K signaling by a chimeric latent membrane protein 1 in Epstein-Barr virus (EBV)+ B cell lymphomas.

    PubMed

    Hatton, Olivia; Lambert, Stacie L; Krams, Sheri M; Martinez, Olivia M

    2012-01-01

    The B lymphotrophic γ-herpesvirus EBV is associated with a variety of lymphoid- and epithelial-derived malignancies, including B cell lymphomas in immunocompromised and immunosuppressed individuals. The primary oncogene of EBV, latent membrane protein 1 (LMP1), activates the PI3K/Akt pathway to induce the autocrine growth factor, IL-10, in EBV-infected B cells, but the mechanisms underlying PI3K activation remain incompletely understood. Using small molecule inhibition and siRNA strategies in human B cell lines expressing a chimeric, signaling-inducible LMP1 protein, nerve growth factor receptor (NGFR)-LMP1, we show that NGFR-LMP1 utilizes Syk to activate PI3K/Akt signaling and induce IL-10 production. NGFR-LMP1 signaling induces phosphorylation of BLNK, a marker of Syk activation. Whereas Src kinases are often required for Syk activation, we show here that PI3K/Akt activation and autocrine IL-10 production by NGFR-LMP1 involves the Src family kinase Fyn. Finally, we demonstrate that NGFR-LMP1 induces phosphorylation of c-Cbl in a Syk- and Fyn-dependent fashion. Our results indicate that the EBV protein LMP1, which lacks the canonical ITAM required for Syk activation, can nevertheless activate Syk, and the Src kinase Fyn, resulting in downstream c-Cbl and PI3K/Akt activation. Fyn, Syk, and PI3K/Akt antagonists thus may present potential new therapeutic strategies that target the oncogene LMP1 for treatment of EBV+ B cell lymphomas.

  7. Pharmacological inhibition of mTORC1 prevents over-activation of the primordial follicle pool in response to elevated PI3K signaling.

    PubMed

    Adhikari, Deepak; Risal, Sanjiv; Liu, Kui; Shen, Yan

    2013-01-01

    The majority of ovarian primordial follicles must be preserved in a quiescent state to allow for the regular production of gametes over the female reproductive lifespan. However, the molecular mechanism that maintains the long quiescence of primordial follicles is poorly understood. Under certain pathological conditions, the entire pool of primordial follicles matures simultaneously leading to an accelerated loss of primordial follicles and to premature ovarian failure (POF). We have previously shown that loss of Pten (phosphatase and tensin homolog deleted on chromosome ten) in mouse oocytes leads to premature activation of the entire pool of primordial follicles, subsequent follicular depletion in early adulthood, and the onset of POF. Lack of PTEN leads to increased phosphatidylinositol 3-kinase (PI3K)-Akt and mammalian target of rapamycin complex 1 (mTORC1) signaling in the oocytes. To study the functional and pathological roles of elevated mTORC1 signaling in the oocytes, we treated the Pten-mutant mice with the specific mTORC1 inhibitor rapamycin. When administered to Pten-deficient mice prior to the activation of the primordial follicles, rapamycin effectively prevented global follicular activation and preserved the ovarian reserve. These results provide a rationale for exploring the possible use of rapamycin as a drug for the preservation of the primordial follicle pool, and the possible prevention of POF.

  8. 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

  9. Heterogeneity between triple negative breast cancer cells due to differential activation of Wnt and PI3K/AKT pathways.

    PubMed

    Martínez-Revollar, Gabriela; Garay, Erika; Martin-Tapia, Dolores; Nava, Porfirio; Huerta, Miriam; Lopez-Bayghen, Esther; Meraz-Cruz, Noemí; Segovia, José; González-Mariscal, Lorenza

    2015-11-15

    The lack of a successful treatment for triple-negative breast cancer demands the study of the heterogeneity of cells that constitute these tumors. With this aim, two clones from triple negative breast MDA-MB-231 cancer cells were isolated: One with fibroblast-like appearance (F) and another with semi-epithelial (SE) morphology. Cells of the F clone have a higher migration and tumorigenesis capacity than SE cells, suggesting that these cells are in a more advanced stage of epithelial to mesenchymal transformation. In agreement, F cells have a diminished expression of the tight junction proteins claudins 1 and 4, and an increased content of β-catenin. The latter is due to an augmented activity of the canonical Wnt route and of the EGFR/PI3K/mTORC2/AKT pathway favoring the cytoplasmic accumulation of β-catenin and its transcriptional activity. In addition, F cells display increased phosphorylation of β-catenin at Tyr654 by Src. These changes favor in F cells, the over-expression of Snail that promotes EMT. Finally, we observe that both F and SE cells display markers of cancer stem cells, which are more abundant in the F clone.

  10. A senescence secretory switch mediated by PI3K/AKT/mTOR activation controls chemoprotective endothelial secretory responses.

    PubMed

    Bent, Eric H; Gilbert, Luke A; Hemann, Michael T

    2016-08-15

    Cancer therapy targets malignant cells that are surrounded by a diverse complement of nonmalignant stromal cells. Therapy-induced damage of normal cells can alter the tumor microenvironment, causing cellular senescence and activating cancer-promoting inflammation. However, how these damage responses are regulated (both induced and resolved) to preserve tissue homeostasis and prevent chronic inflammation is poorly understood. Here, we detail an acute chemotherapy-induced secretory response that is self-limiting in vitro and in vivo despite the induction of cellular senescence. We used tissue-specific knockout mice to demonstrate that endothelial production of the proinflammatory cytokine IL-6 promotes chemoresistance and show that the chemotherapeutic doxorubicin induces acute IL-6 release through reactive oxygen species-mediated p38 activation in vitro. Doxorubicin causes endothelial senescence but, surprisingly, without a typical senescence secretory response. We found that endothelial cells repress senescence-associated inflammation through the down-regulation of PI3K/AKT/mTOR signaling and that reactivation of this pathway restores senescence-associated inflammation. Thus, we describe a mechanism by which damage-associated paracrine secretory responses are restrained to preserve tissue homeostasis and prevent chronic inflammation. PMID:27566778

  11. Opisthorchis viverrini infection activates the PI3K/ AKT/PTEN and Wnt/β-catenin signaling pathways in a Cholangiocarcinogenesis model.

    PubMed

    Yothaisong, Supak; Thanee, Malinee; Namwat, Nisana; Yongvanit, Puangrat; Boonmars, Thidarut; Puapairoj, Anucha; Loilome, Watcharin

    2014-01-01

    Opisthorchis viverrini (Ov) infection is the major etiological factor for cholangiocarcinoma (CCA), especially in northeast Thailand. We have previously reported significant involvement of PI3K/AKT/PTEN and Wnt/β- catenin in human CCA tissues. The present study, therefore, examined the expression and activation of PI3K/ AKT/PTEN and Wnt/β-catenin signaling components during Ov-induced cholangiocarcinogenesis in a hamster animal model. Hamsters were divided into two groups; non-treated and Ov plus NDMA treated. The results of immunohistochemical staining showed an upregulation of PI3K/AKT signaling as determined by elevated expression of the p85α-regulatory and p110α-catalytic subunits of PI3K as well as increased expression and activation of AKT during cholangiocarcinogenesis. Interestingly, the staining intensity of activated AKT (p-AKT) increased in the apical regions of the bile ducts and strong staining was detected where the liver fluke resides. Moreover, PTEN, a negative regulator of PI3K/AKT, was suppressed by decreased expression and increased phosphorylation during cholangiocarcinogenesis. We also detected upregulation of Wnt/β-catenin signaling as determined by increased positive staining of Wnt3, Wnt3a, Wnt5a, Wnt7b and β-catenin, corresponded with the period of cholangiocarcinogenesis. Furthermore, nuclear staining of β-catenin was observed in CCA tissues. Our results suggest the liver fluke infection causes chronic inflammatory conditions which lead to upregulation of the PI3K/AKT and Wnt/β-catenin signaling pathways which may drive CCA carcinogenesis. These results provide useful information for drug development, prevention and treatment of CCA. PMID:25556493

  12. Activation of Robo1 signaling of breast cancer cells by Slit2 from stromal fibroblast restrains tumorigenesis via blocking PI3K/Akt/β-catenin pathway.

    PubMed

    Chang, Po-Hao; Hwang-Verslues, Wendy W; Chang, Yi-Cheng; Chen, Chun-Chin; Hsiao, Michael; Jeng, Yung-Ming; Chang, King-Jen; Lee, Eva Y-H P; Shew, Jin-Yuh; Lee, Wen-Hwa

    2012-09-15

    Tumor microenvironment plays a critical role in regulating tumor progression by secreting factors that mediate cancer cell growth. Stromal fibroblasts can promote tumor growth through paracrine factors; however, restraint of malignant carcinoma progression by the microenvironment also has been observed. The mechanisms that underlie this paradox remain unknown. Here, we report that the tumorigenic potential of breast cancer cells is determined by an interaction between the Robo1 receptor and its ligand Slit2, which is secreted by stromal fibroblasts. The presence of an active Slit2/Robo1 signal blocks the translocation of β-catenin into nucleus, leading to downregulation of c-myc and cyclin D1 via the phosphoinositide 3-kinase (PI3K)/Akt pathway. Clinically, high Robo1 expression in the breast cancer cells correlates with increased survival in patients with breast cancer, and low Slit2 expression in the stromal fibroblasts is associated with lymph node metastasis. Together, our findings explain how a specific tumor microenvironment can restrain a given type of cancer cell from progression and show that both stromal fibroblasts and tumor cell heterogeneity affect breast cancer outcomes.

  13. Methylglyoxal induces platelet hyperaggregation and reduces thrombus stability by activating PKC and inhibiting PI3K/Akt pathway.

    PubMed

    Hadas, Karin; Randriamboavonjy, Voahanginirina; Elgheznawy, Amro; Mann, Alexander; Fleming, Ingrid

    2013-01-01

    Diabetes is characterized by a dysregulation of glucose homeostasis and platelets from patients with diabetes are known to be hyper-reactive and contribute to the accelerated development of vascular diseases. Since many of the deleterious effects of glucose have been attributed to its metabolite methylgyloxal (MG) rather than to hyperglycemia itself, the aim of the present study was to characterize the effects of MG on platelet function. Washed human platelets were pre-incubated for 15 min with MG and platelet aggregation, adhesion on matrix-coated slides and signaling (Western blot) were assessed ex vivo. In vivo, the effect of MG on thrombus formation was determined using the FeCl3-induced carotid artery injury model. MG potentiated thrombin-induced platelet aggregation and dense granule release, but inhibited platelet spreading on fibronectin and collagen. In vivo, MG accelerated thrombus formation but decreased thrombus stability. At the molecular level, MG increased intracellular Ca(2+) and activated classical PKCs at the same time as inhibiting PI3K/Akt and the β3-integrin outside-in signaling. In conclusion, these findings indicate that the enhanced MG concentration measured in diabetic patients can directly contribute to the platelet dysfunction associated with diabetes characterized by hyperaggregability and reduced thrombus stability.

  14. SECTM1 Produced by Tumor Cells Attracts Human Monocytes Via CD7-mediated Activation of the PI3K Pathway

    PubMed Central

    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.

    2013-01-01

    Tumor-associated macrophages (TAMs) play 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 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. PMID:24157461

  15. Estrogen receptor beta growth-inhibitory effects are repressed through activation of MAPK and PI3K signalling in mammary epithelial and breast cancer cells.

    PubMed

    Cotrim, C Z; Fabris, V; Doria, M L; Lindberg, K; Gustafsson, J-Å; Amado, F; Lanari, C; Helguero, L A

    2013-05-01

    Two thirds of breast cancers express estrogen receptors (ER). ER alpha (ERα) mediates breast cancer cell proliferation, and expression of ERα is the standard choice to indicate adjuvant endocrine therapy. ERbeta (ERβ) inhibits growth in vitro; its effects in vivo have been incompletely investigated and its role in breast cancer and potential as alternative target in endocrine therapy needs further study. In this work, mammary epithelial (EpH4 and HC11) and breast cancer (MC4-L2) cells with endogenous ERα and ERβ expression and T47-D human breast cancer cells with recombinant ERβ (T47-DERβ) were used to explore effects exerted in vitro and in vivo by the ERβ agonists 2,3-bis (4-hydroxy-phenyl)-propionitrile (DPN) and 7-bromo-2-(4-hydroxyphenyl)-1,3-benzoxazol-5-ol (WAY). In vivo, ERβ agonists induced mammary gland hyperplasia and MC4-L2 tumour growth to a similar extent as the ERα agonist 4,4',4''-(4-propyl-(1H)-pyrazole-1,3,5-triyl) trisphenol (PPT) or 17β-estradiol (E2) and correlated with higher number of mitotic and lower number of apoptotic features. In vitro, in MC4-L2, EpH4 or HC11 cells incubated under basal conditions, ERβ agonists induced apoptosis measured as upregulation of p53 and apoptosis-inducible factor protein levels and increased caspase 3 activity, whereas PPT and E2 stimulated proliferation. However, when extracellular signal-regulated kinase 1 and 2 (ERK ½) were activated by co-incubation with basement membrane extract or epidermal growth factor, induction of apoptosis by ERβ agonists was repressed and DPN induced proliferation in a similar way as E2 or PPT. In a context of active ERK ½, phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/RAC-alpha serine/threonine-protein kinase (AKT) signalling was necessary to allow proliferation stimulated by ER agonists. Inhibition of MEK ½ with UO126 completely restored ERβ growth-inhibitory effects, whereas inhibition of PI3K by LY294002 inhibited ERβ-induced proliferation. These

  16. 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

  17. Anti-Fibrotic Actions of Interleukin-10 against Hypertrophic Scarring by Activation of PI3K/AKT and STAT3 Signaling Pathways in Scar-Forming Fibroblasts

    PubMed Central

    Cai, Weixia; Bai, Xiaozhi; Fang, Xiaobing; Hu, Xiaolong; Wang, Yaojun; Wang, Hongtao; Zheng, Zhao; Su, Linlin; Hu, Dahai; Zhu, Xiongxiang

    2014-01-01

    Background The hypertrophic scar (HS) is a serious fibrotic skin condition and a major clinical problem. Interleukin-10 (IL-10) has been identified as a prospective scar-improving compound based on preclinical trials. Our previous work showed that IL-10 has anti-fibrotic effects in transforming growth factor (TGF)-β1-stimulated fibroblasts, as well as potential therapeutic benefits for the prevention and reduction of scar formation. However, relatively little is known about the mechanisms underlying IL-10-mediated anti-fibrotic and scar-improvement actions. Objective To explore the expression of the IL-10 receptor in human HS tissue and primary HS fibroblasts (HSFs), and the molecular mechanisms contributing to the anti-fibrotic and scar-improvement capabilities of IL-10. Methods Expression of the IL-10 receptor was assessed in HS tissue and HSFs by immunohistochemistry, immunofluorescence microscopy, and polymerase chain reaction analysis. Primary HSFs were treated with IL-10, a specific phosphatidylinositol 3 kinase (PI3K) inhibitor (LY294002) or a function-blocking antibody against the IL-10 receptor (IL-10RB). Next, Western blot analysis was used to evaluate changes in the phosphorylation status of AKT and signal transducers and activators of transcription (STAT) 3, as well as the expression levels of fibrosis-related proteins. Results HS tissue and primary HSFs were characterized by expression of the IL-10 receptor and by high expression of fibrotic markers relative to normal controls. Primary HSFs expressed the IL-10 receptor, while IL-10 induced AKT and STAT3 phosphorylation in these cells. In addition, LY294002 blocked AKT and STAT phosphorylation, and also up-regulated expression levels of type I and type III collagen (Col 1 and Col 3) and alpha-smooth muscle actin (α-SMA) in IL-10-treated cells. Similarly, IL-10RB reduced STAT3/AKT phosphorylation and blocked the IL-10-mediated mitigation of fibrosis in HSFs. Conclusion IL-10 apparently inhibits

  18. Basic fibroblast growth factor promotes melanocyte migration via activating PI3K/Akt-Rac1-FAK-JNK and ERK signaling pathways.

    PubMed

    Shi, Hongxue; Lin, Beibei; Huang, Yan; Wu, Jiang; Zhang, Hongyu; Lin, Cai; Wang, Zhouguang; Zhu, Jingjing; Zhao, Yingzhen; Fu, Xiaobing; Lou, Zhencai; Li, Xiaokun; Xiao, Jian

    2016-09-01

    Vitiligo is a depigmentation disorder characterized by loss of functional melanocytes of the skin epidermis. The pathogenesis of vitiligo remains elusive. The purpose of this study is to investigate the effects of basic fibroblast growth factor (bFGF) on melanocyte migration, including its biochemical mechanism using transwell assay in vitro. We found that melanocyte treated with bFGF showed a significant increase in migration and cytoskeletal rearrangement. These changes were associated with increased activation of PI3K/Akt, Rac1, FAK, JNK, and ERK. Likewise, reduction of PI3K/Akt, Rac1, FAK, JNK, and ERK activity using selective inhibitors or siRNA was associated with impediment of bFGF-induced melanocyte migration. In addition, activity of Rac1, FAK, and JNK was reduced in cells in which PI3K/Akt was inhibited, activity of FAK and JNK was reduced in cells in which the Rac1 was inhibited, and activity of JNK was reduced in cells in which the FAK was inhibited. Collectively, these data demonstrate that bFGF facilitated melanocyte migration via PI3K/Akt-Rac1-FAK-JNK and ERK signaling pathways. © 2016 IUBMB Life, 68(9):735-747, 2016. PMID:27350596

  19. 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.

  20. A novel mechanism for momordin Ic-induced HepG2 apoptosis: involvement of PI3K- and MAPK-dependent PPARγ activation.

    PubMed

    Wang, Jing; Yuan, Li; Xiao, Haifang; Wang, Chan; Xiao, Chunxia; Wang, Yutang; Liu, Xuebo

    2014-05-01

    Momordin Ic is a natural triterpenoid saponin found in various Chinese and Japanese natural medicines such as the fruit of Kochia scoparia (L.) Schrad. Momordin Ic has been previously demonstrated to induce HepG2 cell apoptosis in a ROS-mediated PI3K and MAPK pathway-dependent manner. In the present study, the underlying mechanisms of PI3K and MAPK pathway-mediated PPARγ, and PGC-1α co-regulator activation, as well as the effects of downstream proteins, COX-2 and FoxO4, on cell apoptosis were investigated. The results demonstrated that momordin Ic activated PPARγ and inhibited COX-2. PGC-1α and FoxO4 expressions were increased by the PI3K or MAPK pathways. Furthermore, PPARγ inhibition decreased p-p38 and FoxO4 expression, and restored COX-2 expression. ROS inhibition exerted little effect on PPARγ, COX-2 and FoxO4 expression but affected PGC-1α expression. These results revealed the involvement of PI3K and MAPK-dependent PPARγ activation in momordin Ic-induced apoptosis, providing more detailed information underlying the pro-apoptotic mechanism of momordin Ic in HepG2 cell apoptosis. PMID:24584198

  1. Leader cells regulate collective cell migration via Rac activation in the downstream signaling of integrin β1 and PI3K.

    PubMed

    Yamaguchi, Naoya; Mizutani, Takeomi; Kawabata, Kazushige; Haga, Hisashi

    2015-01-07

    Collective cell migration plays a crucial role in several biological processes, such as embryonic development, wound healing, and cancer metastasis. Here, we focused on collectively migrating Madin-Darby Canine Kidney (MDCK) epithelial cells that follow a leader cell on a collagen gel to clarify the mechanism of collective cell migration. First, we removed a leader cell from the migrating collective with a micromanipulator. This then caused disruption of the cohesive migration of cells that followed in movement, called "follower" cells, which showed the importance of leader cells. Next, we observed localization of active Rac, integrin β1, and PI3K. These molecules were clearly localized in the leading edge of leader cells, but not in follower cells. Live cell imaging using active Rac and active PI3K indicators was performed to elucidate the relationship between Rac, integrin β1, and PI3K. Finally, we demonstrated that the inhibition of these molecules resulted in the disruption of collective migration. Our findings not only demonstrated the significance of a leader cell in collective cell migration, but also showed that Rac, integrin β1, and PI3K are upregulated in leader cells and drive collective cell migration.

  2. The role of CAPE in PI3K/AKT/mTOR activation and oxidative stress on testis torsion.

    PubMed

    Dilber, Yagmur; Inan, Sevinc; Ercan, Gulinnaz Alper; Sencan, Aydin

    2016-01-01

    Ischemia reperfusion injury arises from testicular torsion resulting in a loss of spermatogenesis and significant germ cell apoptosis. This study evaluates the prooxidant/antioxidant effects of caffeic acid phenethyl ester (CAPE) through PI3K/AKT/mTOR signal pathways on testis torsion. A total of (28) male Wistar rats were divided randomly into 4 groups (n=7 for each group):group A (sham) group,group B torsion/detorsion group, group C (saturation group, during four days of CAPE, one dose (10 μmol/kg, i.p)) and group D (a single dose of CAPE 2h after torsion and before detorsion). At the end of the study, unilateral orchiectomies were performed for measurements of MDA and 8OHdG levels, histopathologic and immunohistochemical and TUNEL apoptotic cell examination. Testicular torsion-detorsion led to a significant decrease in the mean values of the Johnsen's scores and a significant increase in the apoptotic cell values of group B. There were no significant differences between group D and group A. In addition, the MDA and 8OHdG levels increased significantly in group B. The MDA and 8OHdG values were lower in group D. However, the 8OHdG levels were higher in group C than the groups A and D. On the other hand, CAPE suppresses mTOR activation and reduces the apoptosis on ischemia/reperfusion damage in rat testis. These results demonstrate that CAPE suppresses mTOR activation and reduces the apoptosis on ischemia/reperfusion damage in rat testis. PMID:26651953

  3. Coactivation of the PI3K/Akt and ERK signaling pathways in PCB153-induced NF-κB activation and caspase inhibition

    SciTech Connect

    Liu, Changjiang; Yang, Jixin; Fu, Wenjuan; Qi, Suqin; Wang, Chenmin; Quan, Chao; Yang, Kedi

    2014-06-15

    Polychlorinated biphenyls (PCBs) are a group of persistent and widely distributed environmental pollutants that have various deleterious effects, e.g., neurotoxicity, endocrine disruption and reproductive abnormalities. In order to verify the hypothesis that the PI3K/Akt and MAPK pathways play important roles in hepatotoxicity induced by PCBs, Sprague–Dawley (SD) rats were dosed with PCB153 intraperitoneally at 0, 4, 16 and 32 mg/kg for five consecutive days; BRL cells (rat liver cell line) were treated with PCB153 (0, 1, 5, and 10 μM) for 24 h. Results indicated that the PI3K/Akt and ERK pathways were activated in vivo and in vitro after exposure to PCB153, and protein levels of phospho-Akt and phospho-ERK were significantly increased. Nuclear factor-κB (NF-κB) activation and caspase-3, -8 and -9 inhibition caused by PCB153 were also observed. Inhibiting the ERK pathway significantly attenuated PCB153-induced NF-κB activation, whereas inhibiting the PI3K/Akt pathway hardly influenced phospho-NF-κB level. However, inhibiting the PI3K/Akt pathway significantly elevated caspase-3, -8 and -9 activities, while the ERK pathway only synergistically regulated caspase-9. Proliferating cell nuclear antigen (PCNA), a reliable indicator of cell proliferation, was also induced. Moreover, PCB153 led to hepatocellular hypertrophy and elevated liver weight. Taken together, PCB153 leads to aberrant proliferation and apoptosis of hepatocytes through NF-κB activation and caspase inhibition, and coactivated PI3K/Akt and ERK pathways play critical roles in PCB153-induced hepatotoxicity. - Highlights: • PCB153 led to hepatotoxicity through NF-κB activation and caspase inhibition. • The PI3K/Akt and ERK pathways were coactivated in vivo and in vitro by PCB153. • The ERK pathway regulated levels of phospho-NF-κB and caspase-9. • The PI3K/Akt pathway regulated levels of caspase-3, -8 and -9.

  4. C6-ceramide nanoliposome suppresses tumor metastasis by eliciting PI3K and PKCζ tumor-suppressive activities and regulating integrin affinity modulation

    PubMed Central

    Zhang, Pu; Fu, Changliang; Hu, Yijuan; Dong, Cheng; Song, Yang; Song, Erqun

    2015-01-01

    Nanoliposomal formulation of C6-ceramide, a proapoptotic sphingolipid metabolite, presents an effective way to treat malignant tumor. Here, we provide evidence that acute treatment (30 min) of melanoma and breast cancer cells with nanoliposomal C6-ceramide (NaL-C6) may suppress cell migration without inducing cell death. By employing a novel flow migration assay, we demonstrated that NaL-C6 decreased tumor extravasation under shear conditions. Compared with ghost nanoliposome, NaL-C6 triggered phosphorylation of PI3K and PKCζ and dephosphorylation of PKCα. Concomitantly, activated PKCζ translocated into cell membrane. siRNA knockdown or pharmacological inhibition of PKCζ or PI3K rescued NaL-C6-mediated suppression of tumor migration. By inducing dephosphorylation of paxillin, PKCζ was responsible for NaL-C6-mediated stress fiber depolymerization and focal adhesion disassembly in the metastatic tumor cells. PKCζ and PI3K regulated cell shear-resistant adhesion in a way that required integrin αvβ3 affinity modulation. In conclusion, we identified a novel role of acute nanoliposomal ceramide treatment in reducing integrin affinity and inhibiting melanoma metastasis by conferring PI3K and PKCζ tumor-suppressive activities. PMID:25792190

  5. The pan-PI3K inhibitor GDC-0941 activates canonical WNT signaling to confer resistance in TNBC cells: resistance reversal with WNT inhibitor.

    PubMed

    Tzeng, Huey-En; Yang, Lixin; Chen, Kemin; Wang, Yafan; Liu, Yun-Ru; Pan, Shiow-Lin; Gaur, Shikha; Hu, Shuya; Yen, Yun

    2015-05-10

    The pan-PI3K inhibitors are one treatment option for triple-negative breast cancer (TNBC). However, this treatment is ineffective for unknown reasons. Here, we report that aberrant expression of wingless-type MMTV integration site family (WNT) and activated WNT signals, which crosstalk with the PI3K-AKT-mTOR signaling pathway through GSK3β, plays the most critical role in resistance to pan-PI3K inhibitors in TNBC cells. GDC-0941 is a pan-PI3K inhibitor that activates the WNT/beta-catenin pathway in TNBC cells through stimulation of WNT secretion. GDC-0941-triggered WNT/beta-catenin pathway activation was observed in MDA-MB-231 and HCC1937 cells, which are TNBC cell lines showing aberrant WNT/beta-catenin activation, and not in SKBR3 and MCF7 cells. This observation is further investigated in vivo. GDC-0941 exhibited minimal tumor inhibition in MDA-MB-231 cells, but it significantly suppressed tumor growth in HER-positive SK-BR3 cells. In vivo mechanism study revealed the activation of WNT/beta-catenin pathway by GDC-0941. A synergistic effect was observed when combined treatment with GDC-0941 and the WNT inhibitor LGK974 at low concentrations in MDA-MB-231 cells. These findings indicated that WNT pathway activation conferred resistance in TNBC cells treated with GDC-0941. This resistance may be further circumvented through combined treatment with pan-PI3K and WNT inhibitors. Future clinical trials of these two inhibitors are warranted.

  6. The pan-PI3K inhibitor GDC-0941 activates canonical WNT signaling to confer resistance in TNBC cells: resistance reversal with WNT inhibitor

    PubMed Central

    Tzeng, Huey-En; Yang, Lixin; Chen, Kemin; Wang, Yafan; Liu, Yun-Ru; Pan, Shiow-Lin; Gaur, Shikha; Hu, Shuya; Yen, Yun

    2015-01-01

    The pan-PI3K inhibitors are one treatment option for triple-negative breast cancer (TNBC). However, this treatment is ineffective for unknown reasons. Here, we report that aberrant expression of wingless-type MMTV integration site family (WNT) and activated WNT signals, which crosstalk with the PI3K-AKT-mTOR signaling pathway through GSK3β, plays the most critical role in resistance to pan-PI3K inhibitors in TNBC cells. GDC-0941 is a pan-PI3K inhibitor that activates the WNT/beta-catenin pathway in TNBC cells through stimulation of WNT secretion. GDC-0941-triggered WNT/beta-catenin pathway activation was observed in MDA-MB-231 and HCC1937 cells, which are TNBC cell lines showing aberrant WNT/beta-catenin activation, and not in SKBR3 and MCF7 cells. This observation is further investigated in vivo. GDC-0941 exhibited minimal tumor inhibition in MDA-MB-231 cells, but it significantly suppressed tumor growth in HER-positive SK-BR3 cells. In vivo mechanism study revealed the activation of WNT/beta-catenin pathway by GDC-0941. A synergistic effect was observed when combined treatment with GDC-0941 and the WNT inhibitor LGK974 at low concentrations in MDA-MB-231 cells. These findings indicated that WNT pathway activation conferred resistance in TNBC cells treated with GDC-0941. This resistance may be further circumvented through combined treatment with pan-PI3K and WNT inhibitors. Future clinical trials of these two inhibitors are warranted. PMID:25857298

  7. Ochratoxin A activates opposing c-MET/PI3K/Akt and MAPK/ERK 1-2 pathways in human proximal tubule HK-2 cells.

    PubMed

    Özcan, Zeynep; Gül, Gizem; Yaman, Ibrahim

    2015-08-01

    Ochratoxin A (OTA) is a mycotoxin produced as a secondary metabolite by filamentous fungi, such as Aspergillus and Penicillium. Because OTA is a common contaminant of food and feeds, humans and animals are frequently exposed to OTA in daily life. It has been classified as a carcinogen in rodents and a possible carcinogen in humans. OTA has been shown to deregulate a variety of different signal transduction pathways in a cell type- and dosage-depending manner resulting in contrasting physiological effects, such as survival or cell death. While the ERK1-2 and JNK/SAPK MAPK pathways are major targets, knowledge about their role in OTA-mediated cell survival and death is fragmented. Similarly, the contribution of the PI3K/Akt pathway to the carcinogenic effect of OTA in proximal tubule cells has not been elucidated in detail. In this study, we demonstrated that OTA induced sustained activation of the PI3K/Akt and MEK/ERK1-2 signaling pathways in a dose- and time-dependent manner in HK-2 cells. Chemical inhibition of ERK1-2 activation or overexpression of dominant-negative and kinase-dead MEK1 leads to increased cell viability and decreased apoptosis in OTA-treated cells. Blockage of PI3K/Akt with Wortmannin aggravated the negative effect of OTA on cell viability and increased the levels of apoptosis. Moreover, we identified the c-MET proto-oncogene as an upstream receptor tyrosine kinase responsible for OTA-induced activation of PI3K/Akt signaling in HK-2 cells. Our data suggest that OTA may potentiate carcinogenesis by sustained activation of c-MET/PI3K/Akt signaling through suppression of apoptosis induced by MEK/ERK1-2 activation in damaged renal proximal tubule epithelial cells. PMID:25002221

  8. Activation of PI3K-Akt-GSK3{beta} pathway mediates hepatocyte growth factor inhibition of RANTES expression in renal tubular epithelial cells

    SciTech Connect

    Gong Rujun . E-mail: rgong@Brown.edu; Rifai, Abdalla; Dworkin, Lance D.

    2005-04-29

    Hepatocyte growth factor (HGF) was recently reported to ameliorate renal inflammation in a rat model of chronic renal failure. HGF exerted its action through suppression of RANTES expression in renal tubules. In the present study, we utilized an in vitro model of human kidney proximal tubule epithelial cells (HKC) to elucidate the mechanisms of RANTES suppression by HGF. HGF significantly suppressed basal and TNF-{alpha}-induced mRNA and protein expression of RANTES in a time and dose dependent fashion. HGF elicited PI3K-Akt activation and inhibited GSK3, a downstream transducer of PI3K-Akt, by inhibitory phosphorylation at Ser-9. When the PI3K-Akt pathway was blocked by wortmannin, HGF inhibition of RANTES was abrogated, demonstrating that the PI3K-Akt pathway is necessary for HGF action. In addition, specific inhibition of GSK3 activity by lithium ion suppressed basal and TNF-{alpha}-induced RANTES expression, reminiscent of the action of HGF. To further investigate the role of GSK3 in modulating RANTES expression, we examined the effect of forced expression of wild type GSK3{beta} or an uninhibitable mutant GSK3{beta}, in which the regulatory Ser-9 residue is changed to alanine (S9A-GSK3{beta}) in HKC. Overexpression of wild type GSK3{beta} did not alter the inhibitory action of HGF on RANTES. In contrast, expression of S9A-GSK3{beta} abolished HGF inhibition of basal and TNF-{alpha} stimulated RANTES expression. These findings suggest that PI3K-Akt activation and subsequent inhibitory phosphorylation of GSK3{beta} are required for HGF-induced suppression of RANTES in HKC.

  9. Activation of GLP-1 Receptor Enhances Neuronal Base Excision Repair via PI3K-AKT-Induced Expression of Apurinic/Apyrimidinic Endonuclease 1

    PubMed Central

    Yang, Jenq-Lin; Chen, Wei-Yu; Chen, Yin-Ping; Kuo, Chao-Ying; Chen, Shang-Der

    2016-01-01

    Glucagon-like peptide-1 (GLP-1) is an intestinal-secreted incretin that increases cellular glucose up-take to decrease blood sugar. Recent studies, however, suggest that the function of GLP-1 is not only to decrease blood sugar, but also acts as a neurotrophic factor that plays a role in neuronal survival, neurite outgrowth, and protects synaptic plasticity and memory formation from effects of β-amyloid. Oxidative DNA damage occurs during normal neuron-activity and in many neurological diseases. Our study describes how GLP-1 affected the ability of neurons to ameliorate oxidative DNA damage. We show that activation of GLP-1 receptor (GLP-1R) protect cortical neurons from menadione induced oxidative DNA damage via a signaling pathway involving enhanced DNA repair. GLP-1 stimulates DNA repair by activating the cyclic AMP response element binding protein (CREB) which, consequently, induces the expression of apurinic/apyrimidinic endonuclease 1 (APE1), a key enzyme in the base excision DNA repair (BER) pathway. In this study, APE1 expression was down-regulated as a consequence phosphatidylinositol-3 kinase (PI3K) suppression by the inhibitor LY294002, but not by the suppression of MEK activity. Ischemic stroke is typically caused by overwhelming oxidative-stress in brain cells. Administration of exentin-4, an analogue of GLP-1, efficiently enhanced DNA repair in brain cells of ischemic stroke rats. Our study suggests that a new function of GLP-1 is to elevate DNA repair by inducing the expression of the DNA repair protein APE1. PMID:27698937

  10. Activation of GLP-1 Receptor Enhances Neuronal Base Excision Repair via PI3K-AKT-Induced Expression of Apurinic/Apyrimidinic Endonuclease 1

    PubMed Central

    Yang, Jenq-Lin; Chen, Wei-Yu; Chen, Yin-Ping; Kuo, Chao-Ying; Chen, Shang-Der

    2016-01-01

    Glucagon-like peptide-1 (GLP-1) is an intestinal-secreted incretin that increases cellular glucose up-take to decrease blood sugar. Recent studies, however, suggest that the function of GLP-1 is not only to decrease blood sugar, but also acts as a neurotrophic factor that plays a role in neuronal survival, neurite outgrowth, and protects synaptic plasticity and memory formation from effects of β-amyloid. Oxidative DNA damage occurs during normal neuron-activity and in many neurological diseases. Our study describes how GLP-1 affected the ability of neurons to ameliorate oxidative DNA damage. We show that activation of GLP-1 receptor (GLP-1R) protect cortical neurons from menadione induced oxidative DNA damage via a signaling pathway involving enhanced DNA repair. GLP-1 stimulates DNA repair by activating the cyclic AMP response element binding protein (CREB) which, consequently, induces the expression of apurinic/apyrimidinic endonuclease 1 (APE1), a key enzyme in the base excision DNA repair (BER) pathway. In this study, APE1 expression was down-regulated as a consequence phosphatidylinositol-3 kinase (PI3K) suppression by the inhibitor LY294002, but not by the suppression of MEK activity. Ischemic stroke is typically caused by overwhelming oxidative-stress in brain cells. Administration of exentin-4, an analogue of GLP-1, efficiently enhanced DNA repair in brain cells of ischemic stroke rats. Our study suggests that a new function of GLP-1 is to elevate DNA repair by inducing the expression of the DNA repair protein APE1.

  11. Brown Pine Leaf Extract and Its Active Component Trans-Communic Acid Inhibit UVB-Induced MMP-1 Expression by Targeting PI3K.

    PubMed

    Huh, Won Bum; Kim, Jong-Eun; Kang, Young-Gyu; Park, Gaeun; Lim, Tae-gyu; Kwon, Jung Yeon; Song, Da Som; Jeong, Eun Hee; Lee, Charles C; Son, Joe Eun; Seo, Sang Gwon; Lee, Eunjung; Kim, Jong Rhan; Lee, Chang Yong; Park, Jun Seong; Lee, Ki Won

    2015-01-01

    Japanese red pine (Pinus densiflora) is widely present in China, Japan, and Korea. Its green pine leaves have traditionally been used as a food as well as a coloring agent. After being shed, pine leaves change their color from green to brown within two years, and although the brown pine leaves are abundantly available, their value has not been closely assessed. In this study, we investigated the potential anti-photoaging properties of brown pine leaves for skin. Brown pine leaf extract (BPLE) inhibited UVB-induced matrix metalloproteinase-1 (MMP-1) expression to a greater extent than pine leaf extract (PLE) in human keratinocytes and a human skin equivalent model. HPLC analysis revealed that the quantity of trans-communic acid (TCA) and dehydroabietic acid (DAA) significantly increases when the pine leaf color changes from green to brown. BPLE and TCA elicited reductions in UVB-induced MMP-1 mRNA expression and activator protein-1 (AP-1) transactivation by reducing DNA binding activity of phospho-c-Jun, c-fos and Fra-1. BPLE and TCA also inhibited UVB-induced Akt phosphorylation, but not mitogen activated protein kinase (MAPK), known regulators of AP-1 transactivation. We additionally found that BPLE and TCA inhibited phosphoinositide 3-kinase (PI3K), the upstream kinase of Akt, in vitro. In summary, both BPLE and its active component TCA exhibit protective effects against UVB-induced skin aging. Taken together, these findings underline the potential for BPLE and TCA to be utilized as anti-wrinkling agents and cosmetic ingredients, as they suppress UVB-induced MMP-1 expression.

  12. Brown Pine Leaf Extract and Its Active Component Trans-Communic Acid Inhibit UVB-Induced MMP-1 Expression by Targeting PI3K

    PubMed Central

    Park, Gaeun; Lim, Tae-gyu; Kwon, Jung Yeon; Song, Da Som; Jeong, Eun Hee; Lee, Charles C.; Son, Joe Eun; Seo, Sang Gwon; Lee, Eunjung; Kim, Jong Rhan; Lee, Chang Yong; Park, Jun Seong; Lee, Ki Won

    2015-01-01

    Japanese red pine (Pinus densiflora) is widely present in China, Japan, and Korea. Its green pine leaves have traditionally been used as a food as well as a coloring agent. After being shed, pine leaves change their color from green to brown within two years, and although the brown pine leaves are abundantly available, their value has not been closely assessed. In this study, we investigated the potential anti-photoaging properties of brown pine leaves for skin. Brown pine leaf extract (BPLE) inhibited UVB-induced matrix metalloproteinase-1 (MMP-1) expression to a greater extent than pine leaf extract (PLE) in human keratinocytes and a human skin equivalent model. HPLC analysis revealed that the quantity of trans-communic acid (TCA) and dehydroabietic acid (DAA) significantly increases when the pine leaf color changes from green to brown. BPLE and TCA elicited reductions in UVB-induced MMP-1 mRNA expression and activator protein-1 (AP-1) transactivation by reducing DNA binding activity of phospho-c-Jun, c-fos and Fra-1. BPLE and TCA also inhibited UVB-induced Akt phosphorylation, but not mitogen activated protein kinase (MAPK), known regulators of AP-1 transactivation. We additionally found that BPLE and TCA inhibited phosphoinositide 3-kinase (PI3K), the upstream kinase of Akt, in vitro. In summary, both BPLE and its active component TCA exhibit protective effects against UVB-induced skin aging. Taken together, these findings underline the potential for BPLE and TCA to be utilized as anti-wrinkling agents and cosmetic ingredients, as they suppress UVB-induced MMP-1 expression. PMID:26066652

  13. Accelerated Tumor Growth Mediated by Sub-lytic Levels of Antibody-Induced Complement Activation is Associated with Activation of the PI3K/AKT Survival Pathway

    PubMed Central

    Wu, Xiaohong; Ragupathi, Govind; Panageas, Katherine; Hong, Feng; Livingston, Philip O.

    2013-01-01

    Purpose We addressed the possibility that low levels of tumor cell bound antibodies targeting gangliosides might accelerate tumor growth. Experimental Design To test this hypothesis, we treated mice with a range of mAb doses against GM2, GD2, GD3 and CD20 after challenge with tumors expressing these antigens and tested the activity of the same mAbs in-vitro. We also explored the mechanisms behind the complement-mediated tumor growth acceleration that we observed and an approach to overcome it. Results Serologically detectable levels of IgM-mAb against GM2 are able to delay or prevent tumor growth of high GM2-expressing cell lines both in-vitro and in a SCID mouse model, while very low levels of this mAb resulted in slight but consistent acceleration of tumor growth in both settings. Surprisingly, this is not restricted to IgM antibodies targeting GM2 but consistent against IgG-mAb targeting GD3 as well. These findings were mirrored by in-vitro studies with antibodies against these antigens as well as GD2 and CD20 (with Rituxan), and shown to be complement-dependent in all cases. Complement-mediated accelerated growth of cultured tumor cell lines initiated by low mAb levels was associated with activation of the PI3K/AKT survival pathway and significantly elevated levels of both p-AKT and p-PRAS40. This complement-mediated PI3K-activation and accelerated tumor growth in-vitro and in-vivo are eliminated by PI3K-inhibitors NVP-BEZ235 and Wortmannin. These PI3K-inhibitors also significantly increased efficacy of high doses of these 4 mAbs. Conclusion Our findings suggest that manipulation of the PI3K/AKT pathway and its signaling network can significantly increase the potency of passively administered mAbs and vaccine-induced-antibodies targeting a variety of tumor-cell-surface-antigens. PMID:23833306

  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. 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.

  16. Abnormal Protein Glycosylation and Activated PI3K/Akt/mTOR Pathway: Role in Bladder Cancer Prognosis and Targeted Therapeutics

    PubMed Central

    Lima, Luís; Peixoto, Andreia; Fernandes, Elisabete; Neves, Diogo; Neves, Manuel; Gaiteiro, Cristiana; Tavares, Ana; Gil da Costa, Rui M.; Cruz, Ricardo; Amaro, Teresina; Oliveira, Paula A.; Ferreira, José Alexandre; Santos, Lúcio L.

    2015-01-01

    Muscle invasive bladder cancer (MIBC, stage ≥T2) is generally associated with poor prognosis, constituting the second most common cause of death among genitourinary tumours. Due to high molecular heterogeneity significant variations in the natural history and disease outcome have been observed. This has also delayed the introduction of personalized therapeutics, making advanced stage bladder cancer almost an orphan disease in terms of treatment. Altered protein glycosylation translated by the expression of the sialyl-Tn antigen (STn) and its precursor Tn as well as the activation of the PI3K/Akt/mTOR pathway are cancer-associated events that may hold potential for patient stratification and guided therapy. Therefore, a retrospective design, 96 bladder tumours of different stages (Ta, T1-T4) was screened for STn and phosphorylated forms of Akt (pAkt), mTOR (pmTOR), S6 (pS6) and PTEN, related with the activation of the PI3K/Akt/mTOR pathway. In our series the expression of Tn was residual and was not linked to stage or outcome, while STn was statically higher in MIBC when compared to non-muscle invasive tumours (p = 0.001) and associated decreased cancer-specific survival (log rank p = 0.024). Conversely, PI3K/Akt/mTOR pathway intermediates showed an equal distribution between non-muscle invasive bladder cancer (NMIBC) and MIBC and did not associate with cancer-specif survival (CSS) in any of these groups. However, the overexpression of pAKT, pmTOR and/or pS6 allowed discriminating STn-positive advanced stage bladder tumours facing worst CSS (p = 0.027). Furthermore, multivariate Cox regression analysis revealed that overexpression of PI3K/Akt/mTOR pathway proteins in STn+ MIBC was independently associated with approximately 6-fold risk of death by cancer (p = 0.039). Mice bearing advanced stage chemically-induced bladder tumours mimicking the histological and molecular nature of human tumours were then administrated with mTOR-pathway inhibitor sirolimus (rapamycin

  17. Abnormal Protein Glycosylation and Activated PI3K/Akt/mTOR Pathway: Role in Bladder Cancer Prognosis and Targeted Therapeutics.

    PubMed

    Costa, Céu; Pereira, Sofia; Lima, Luís; Peixoto, Andreia; Fernandes, Elisabete; Neves, Diogo; Neves, Manuel; Gaiteiro, Cristiana; Tavares, Ana; Gil da Costa, Rui M; Cruz, Ricardo; Amaro, Teresina; Oliveira, Paula A; Ferreira, José Alexandre; Santos, Lúcio L

    2015-01-01

    Muscle invasive bladder cancer (MIBC, stage ≥T2) is generally associated with poor prognosis, constituting the second most common cause of death among genitourinary tumours. Due to high molecular heterogeneity significant variations in the natural history and disease outcome have been observed. This has also delayed the introduction of personalized therapeutics, making advanced stage bladder cancer almost an orphan disease in terms of treatment. Altered protein glycosylation translated by the expression of the sialyl-Tn antigen (STn) and its precursor Tn as well as the activation of the PI3K/Akt/mTOR pathway are cancer-associated events that may hold potential for patient stratification and guided therapy. Therefore, a retrospective design, 96 bladder tumours of different stages (Ta, T1-T4) was screened for STn and phosphorylated forms of Akt (pAkt), mTOR (pmTOR), S6 (pS6) and PTEN, related with the activation of the PI3K/Akt/mTOR pathway. In our series the expression of Tn was residual and was not linked to stage or outcome, while STn was statically higher in MIBC when compared to non-muscle invasive tumours (p = 0.001) and associated decreased cancer-specific survival (log rank p = 0.024). Conversely, PI3K/Akt/mTOR pathway intermediates showed an equal distribution between non-muscle invasive bladder cancer (NMIBC) and MIBC and did not associate with cancer-specif survival (CSS) in any of these groups. However, the overexpression of pAKT, pmTOR and/or pS6 allowed discriminating STn-positive advanced stage bladder tumours facing worst CSS (p = 0.027). Furthermore, multivariate Cox regression analysis revealed that overexpression of PI3K/Akt/mTOR pathway proteins in STn+ MIBC was independently associated with approximately 6-fold risk of death by cancer (p = 0.039). Mice bearing advanced stage chemically-induced bladder tumours mimicking the histological and molecular nature of human tumours were then administrated with mTOR-pathway inhibitor sirolimus (rapamycin

  18. Abnormal Protein Glycosylation and Activated PI3K/Akt/mTOR Pathway: Role in Bladder Cancer Prognosis and Targeted Therapeutics.

    PubMed

    Costa, Céu; Pereira, Sofia; Lima, Luís; Peixoto, Andreia; Fernandes, Elisabete; Neves, Diogo; Neves, Manuel; Gaiteiro, Cristiana; Tavares, Ana; Gil da Costa, Rui M; Cruz, Ricardo; Amaro, Teresina; Oliveira, Paula A; Ferreira, José Alexandre; Santos, Lúcio L

    2015-01-01

    Muscle invasive bladder cancer (MIBC, stage ≥T2) is generally associated with poor prognosis, constituting the second most common cause of death among genitourinary tumours. Due to high molecular heterogeneity significant variations in the natural history and disease outcome have been observed. This has also delayed the introduction of personalized therapeutics, making advanced stage bladder cancer almost an orphan disease in terms of treatment. Altered protein glycosylation translated by the expression of the sialyl-Tn antigen (STn) and its precursor Tn as well as the activation of the PI3K/Akt/mTOR pathway are cancer-associated events that may hold potential for patient stratification and guided therapy. Therefore, a retrospective design, 96 bladder tumours of different stages (Ta, T1-T4) was screened for STn and phosphorylated forms of Akt (pAkt), mTOR (pmTOR), S6 (pS6) and PTEN, related with the activation of the PI3K/Akt/mTOR pathway. In our series the expression of Tn was residual and was not linked to stage or outcome, while STn was statically higher in MIBC when compared to non-muscle invasive tumours (p = 0.001) and associated decreased cancer-specific survival (log rank p = 0.024). Conversely, PI3K/Akt/mTOR pathway intermediates showed an equal distribution between non-muscle invasive bladder cancer (NMIBC) and MIBC and did not associate with cancer-specif survival (CSS) in any of these groups. However, the overexpression of pAKT, pmTOR and/or pS6 allowed discriminating STn-positive advanced stage bladder tumours facing worst CSS (p = 0.027). Furthermore, multivariate Cox regression analysis revealed that overexpression of PI3K/Akt/mTOR pathway proteins in STn+ MIBC was independently associated with approximately 6-fold risk of death by cancer (p = 0.039). Mice bearing advanced stage chemically-induced bladder tumours mimicking the histological and molecular nature of human tumours were then administrated with mTOR-pathway inhibitor sirolimus (rapamycin

  19. 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

  20. 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

  1. Activation of PI3K/Akt signaling in rostral ventrolateral medulla impairs brain stem cardiovascular regulation that underpins circulatory depression during mevinphos intoxication.

    PubMed

    Tsai, Ching-Yi; Chang, Alice Y W; Chan, Julie Y H; Chan, Samuel H H

    2014-03-01

    As the most widely used pesticides in the globe, the organophosphate compounds are understandably linked with the highest incidence of suicidal poisoning. Whereas the elicited toxicity is often associated with circulatory depression, the underlying mechanisms require further delineation. Employing the pesticide mevinphos as our experimental tool, we evaluated the hypothesis that transcriptional upregulation of nitric oxide synthase II (NOS II) by NF-κB on activation of the PI3K/Akt cascade in the rostral ventrolateral medulla (RVLM), the brain stem site that maintains blood pressure and sympathetic vasomotor tone, underpins the circulatory depressive effects of organophosphate poisons. Microinjection of mevinphos (10 nmol) bilaterally into the RVLM of anesthetized Sprague-Dawley rats induced a progressive hypotension that was accompanied sequentially by an increase (Phase I) and a decrease (Phase II) of an experimental index for the baroreflex-mediated sympathetic vasomotor tone. There were also progressive augmentations in PI3K or Akt enzyme activity and phosphorylation of p85 or Akt(Thr308) subunit in the RVLM that were causally related to an increase in NF-κB transcription activity and elevation in NOS II or peroxynitrite expression. Loss-of-function manipulations of PI3K or Akt in the RVLM significantly antagonized the reduced baroreflex-mediated sympathetic vasomotor tone and hypotension during Phase II mevinphos intoxication, and blunted the increase in NF-κB/NOS II/peroxynitrite signaling. We conclude that activation of the PI3K/Akt cascade, leading to upregulation of NF-κB/NOS II/peroxynitrite signaling in the RVLM, elicits impairment of brain stem cardiovascular regulation that underpins circulatory depression during mevinphos intoxication.

  2. Pseudomonas aeruginosa pyocyanin activates NRF2-ARE-mediated transcriptional response via the ROS-EGFR-PI3K-AKT/MEK-ERK MAP kinase signaling in pulmonary epithelial cells.

    PubMed

    Xu, Ying; Duan, Chaohui; Kuang, Zhizhou; Hao, Yonghua; Jeffries, Jayme L; Lau, Gee W

    2013-01-01

    The redox-active pyocyanin (PCN) secreted by the respiratory pathogen Pseudomonas aeruginosa generates reactive oxygen species (ROS) and causes oxidative stress to pulmonary epithelial cells. Nuclear factor (erythroid-derived 2)-like 2 (NRF2) confers protection against ROS-mediated cell death by inducing the expression of detoxifying enzymes and proteins via its binding to the cis-acting antioxidant response element (ARE). However, a clear relationship between NRF2 and PCN-mediated oxidative stress has not been established experimentally. In this study, we investigated the induction of NRF2-ARE response by PCN in the pulmonary epithelial cells. We analyzed the effect of PCN on NRF2 expression and nuclear translocation in cultured human airway epithelial cells, and in a mouse model of chronic PCN exposure. NRF2-dependent transcription of antioxidative enzymes was also assessed. Furthermore, we used inhibitors to examine the involvement of EGFR and its downstream signaling components that mediate NRF2-ARE-activation in response to PCN. PCN enhances the nuclear NRF2 accumulation and activates the transcription of ARE-mediated antioxidant genes. Furthermore, PCN activates NRF2 by inducing the EGFR-phosphoinositide-3-kinase (PI3K) signaling pathway and its main downstream effectors, AKT and MEK1/2-ERK1/2 MAP kinases. Inhibition of the EGFR-PI3K signaling markedly attenuates PCN-stimulated NRF2 accumulation in the nucleus. We demonstrate for the first time that PCN-mediated oxidative stress activates the EGFR-PI3K-AKT/MEK1/2-ERK1/2 MAP kinase signaling pathway, leading to nuclear NRF2 translocation and ARE responsiveness in pulmonary epithelial cells.

  3. Tetramethylpyrazine induces SH-SY5Y cell differentiation toward the neuronal phenotype through activation of the PI3K/Akt/Sp1/TopoIIβ pathway.

    PubMed

    Yan, Yong-Xin; Zhao, Jun-Xia; Han, Shuo; Zhou, Na-Jing; Jia, Zhi-Qiang; Yao, Sheng-Jie; Cao, Cui-Li; Wang, Yan-Ling; Xu, Yan-Nan; Zhao, Juan; Yan, Yun-Li; Cui, Hui-Xian

    2015-12-01

    Tetramethylpyrazine (TMP) is an active compound extracted from the traditional Chinese medicinal herb Chuanxiong. Previously, we have shown that TMP induces human SH-SY5Y neuroblastoma cell differentiation toward the neuronal phenotype by targeting topoisomeraseIIβ (TopoIIβ), a protein implicated in neural development. In the present study, we aimed to elucidate whether the transcriptional factors specificity protein 1 (Sp1) and nuclear factor Y (NF-Y), in addition to the upstream signaling pathways ERK1/2 and PI3K/Akt, are involved in modulating TopoIIβ expression in the neuronal differentiation process. We demonstrated that SH-SY5Y cells treated with TMP (80μM) terminally differentiated into neurons, characterized by increased neuronal markers, tubulin βIII and microtubule associated protein 2 (MAP2), and increased neurite outgrowth, with no negative effect on cell survival. TMP also increased the expression of TopoIIβ, which was accompanied by increased expression of Sp1 in the differentiated neuron-like cells, whereas NF-Y protein levels remained unchanged following the differentiation progression. We also found that the phosphorylation level of Akt, but not ERK1/2, was significantly increased as a result of TMP stimulation. Furthermore, as established by chromatin immunoprecipitation (ChIP) assay, activation of the PI3K/Akt pathway increased Sp1 binding to the promoter of the TopoIIβ gene. Blockage of PI3K/Akt was shown to lead to subsequent inhibition of TopoIIβ expression and neuronal differentiation. Collectively, the results indicate that the PI3K/Akt/Sp1/TopoIIβ signaling pathway is necessary for TMP-induced neuronal differentiation. Our findings offer mechanistic insights into understanding the upstream regulation of TopoIIβ in neuronal differentiation, and suggest potential applications of TMP both in neuroscience research and clinical practice to treat relevant diseases of the nervous system. PMID:26518113

  4. Helicobacter pylori neutrophil-activating protein induces release of histamine and interleukin-6 through G protein-mediated MAPKs and PI3K/Akt pathways in HMC-1 cells.

    PubMed

    Tsai, Chung-Che; Kuo, Ting-Yu; Hong, Zhi-Wei; Yeh, Ying-Chieh; Shih, Kuo-Shun; Du, Shin-Yi; Fu, Hua-Wen

    2015-01-01

    Helicobacter pylori neutrophil-activating protein (HP-NAP) activates several innate leukocytes including neutrophils, monocytes, and mast cells. It has been reported that HP-NAP induces degranulation and interleukin-6 (IL-6) secretion of rat peritoneal mast cells. However, the molecular mechanism is not very clear. Here, we show that HP-NAP activates human mast cell line-1 (HMC-1) cells to secrete histamine and IL-6. The secretion depends on pertussis toxin (PTX)-sensitive heterotrimeric G proteins but not on Toll-like receptor 2. Moreover, HP-NAP induces PTX-sensitive G protein-mediated activation of extracellular signal-regulated kinase 1/2 (ERK1/2), p38-mitogen-activated protein kinase (p38 MAPK), and Akt in HMC-1 cells. Inhibition of ERK1/2, p38 MAPK, or phosphatidylinositol 3-kinase (PI3K) suppresses HP-NAP-induced release of histamine and IL-6 from HMC-1 cells. Thus, the activation of HMC-1 cells by HP-NAP is through Gi-linked G protein-coupled receptor-mediated MAPKs and PI3K/Akt pathways.

  5. Activation of the FAK/PI3K pathway is crucial for AURKA-induced epithelial-mesenchymal transition in laryngeal cancer.

    PubMed

    Yang, Liyun; Zhou, Quan; Chen, Xuehua; Su, Liping; Liu, Bingya; Zhang, Hao

    2016-08-01

    Laryngeal squamous cell carcinoma (LSCC) is one of the most common malignant tumors, and the main cause of death is metastasis. Overexpression of aurora kinase A (AURKA) plays an important role in the metastasis of LSCC. However, the mechanism by which AURKA promotes the metastasis of LSCC is poorly understood. Recent accumulating evidence indicates that epithelial-mesenchymal transition (EMT) may be one of the mechanisms of tumor metastasis. In the present study, we studied whether AURKA may induce EMT to promote the metastasis of LSCC. CCK-8 and plate colony-formation assays were carried out to show that AURKA significantly promoted the proliferation of Hep2 cells. Immunofluorescence staining and western blotting showed that EMT-related proteins changed in a time-dependent manner along with the alteration of AURKA, with decreased expression of N-cadherin, vimentin and slug and increased expression of E-cadherin. Additionally, downregulation of the expression of AURKA inhibited FAK/PI3K pathway activity. Inhibition of the FAK/PI3K pathway caused less mesenchymal-like characteristics and reduced the mobility, migration and invasion of Hep2 cells. In conclusion, AURKA may induce EMT to promote metastasis via activation of the FAK/PI3K pathway in LSCC. Those regulatory factors may present new diagnostic biomarkers and potential therapeutic targets for LSCC. PMID:27373675

  6. Intermolecular biparatopic trapping of ErbB2 prevents compensatory activation of PI3K/AKT via RAS–p110 crosstalk

    PubMed Central

    Tamaskovic, Rastislav; Schwill, Martin; Nagy-Davidescu, Gabriela; Jost, Christian; Schaefer, Dagmar C.; Verdurmen, Wouter P. R.; Schaefer, Jonas V.; Honegger, Annemarie; Plückthun, Andreas

    2016-01-01

    Compensatory mechanisms, such as relief of AKT-ErbB3-negative feedback, are known to desensitize ErbB2-dependent tumours to targeted therapy. Here we describe an adaptation mechanism leading to reactivation of the PI3K/AKT pathway during trastuzumab treatment, which occurs independently of ErbB3 re-phosphorylation. This signalling bypass of phospho-ErbB3 operates in ErbB2-overexpressing cells via RAS-PI3K crosstalk and is attributable to active ErbB2 homodimers. As demonstrated by dual blockade of ErbB2/RAS and ErbB3 by means of pharmacological inhibition, RNA interference or by specific protein binders obstructing the RAS–p110α interaction, both routes must be blocked to prevent reactivation of the PI3K/AKT pathway. Applying these general principles, we developed biparatopic designed ankyrin repeat proteins (DARPins) trapping ErbB2 in a dimerization-incompetent state, which entail pan-ErbB inhibition and a permanent OFF state in the oncogenic signalling, thereby triggering extensive apoptosis in ErbB2-addicted tumours. Thus, these novel insights into mechanisms underlying network robustness provide a guide for overcoming adaptation response to ErbB2/ErbB3-targeted therapy. PMID:27255951

  7. PI3K inhibitors LY294002 and IC87114 reduce inflammation in carrageenan-induced paw oedema and down-regulate inflammatory gene expression in activated macrophages.

    PubMed

    Eräsalo, Heikki; Laavola, Mirka; Hämäläinen, Mari; Leppänen, Tiina; Nieminen, Riina; Moilanen, Eeva

    2015-01-01

    PI3K/Akt pathway is a well-characterized pathway controlling cellular processes such as proliferation, migration and survival, and its role in cancer is vastly studied. There is also evidence to suggest the involvement of this pathway in the regulation of inflammatory responses. In this study, an attempt was made to investigate the role of PI3Ks in acute inflammation in vivo using pharmacological inhibitors against PI3Ks in the carrageenan-induced paw oedema model. A non-selective PI3K inhibitor LY294002 and a PI3Kδ-selective inhibitor IC87114 were used. Both of these inhibitors reduced inflammatory oedema upon carrageenan challenge in the mouse paw. To explain this result, the effects of the two inhibitors on inflammatory gene expression were investigated in activated macrophages. LY294002 and IC87114 prevented Akt phosphorylation as expected and down-regulated the expression of inflammatory factors IL-6, MCP-1,TNFα and iNOS. These findings suggest that PI3K inhibitors could be used to attenuate inflammatory responses and that the mechanism of action behind this effect is the down-regulation of inflammatory gene expression.

  8. Jujuboside A Protects H9C2 Cells from Isoproterenol-Induced Injury via Activating PI3K/Akt/mTOR Signaling Pathway

    PubMed Central

    Han, Dandan; Wan, Changrong; Liu, Fenghua; Xu, Xiaolong; Jiang, Linshu; Xu, Jianqin

    2016-01-01

    Jujuboside A is a kind of the saponins isolated from the seeds of Ziziphus jujuba, which possesses multiple biological effects, such as antianxiety, antioxidant, and anti-inflammatory effects; however, its mediatory effect on isoproterenol-stimulated cardiomyocytes has not been investigated yet. In this study, we tried to detect the protective effect and potential mechanism of JUA on ISO-induced cardiomyocytes injury. H9C2 cells were treated with ISO to induce cell damage. Cells were pretreated with JUA to investigate the effects on the cell viability, morphological changes, light chain 3 conversion, and the activation of PI3K/Akt/mTOR signaling pathway. Results showed that ISO significantly inhibited the cell viability in a time- and dose-dependent manner. JUA pretreatment could reverse the reduction of cell viability and better the injury of H9C2 cells induced by ISO. Western blot analysis showed that JUA could accelerate the phosphorylation of PI3K, Akt, and mTOR. Results also indicated that JUA could significantly decrease the ratio of microtubule-associated protein LC3-II/I in H9C2 cells. Taken together, our research showed that JUA could notably reduce the damage cause by ISO via promoting the phosphorylation of PI3K, Akt, and mTOR and inhibiting LC3 conversion, which may be a potential choice for the treatment of heart diseases. PMID:27293469

  9. 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

  10. The combinatorial activation of the PI3K and Ras/MAPK pathways is sufficient for aggressive tumor formation, while individual pathway activation supports cell persistence

    PubMed Central

    Thompson, Keyata N.; Whipple, Rebecca A.; Yoon, Jennifer R.; Lipsky, Michael; Charpentier, Monica S.; Boggs, Amanda E.; Chakrabarti, Kristi R.; Bhandary, Lekhana; Hessler, Lindsay K.; Martin, Stuart S.; Vitolo, Michele I.

    2015-01-01

    A high proportion of human tumors maintain activation of both the PI3K and Ras/MAPK pathways. In basal-like breast cancer (BBC), PTEN expression is decreased/lost in over 50% of cases, leading to aberrant activation of the PI3K pathway. Additionally, BBC cell lines and tumor models have been shown to exhibit an oncogenic Ras-like gene transcriptional signature, indicating activation of the Ras/MAPK pathway. To directly test how the PI3K and Ras/MAPK pathways contribute to tumorigenesis, we deleted PTEN and activated KRas within non-tumorigenic MCF-10A breast cells. Neither individual mutation was sufficient to promote tumorigenesis, but the combination promoted robust tumor growth in mice. However, in vivo bioluminescence reveals that each mutation has the ability to promote a persistent phenotype. Inherent in the concept of tumor cell dormancy, a stage in which residual disease is present but remains asymptomatic, viable cells with each individual mutation can persist in vivo during a period of latency. The persistent cells were excised from the mice and showed increased levels of the cell cycle arrest proteins p21 and p27 compared to the aggressively growing PTEN−/−KRAS(G12V) cells. Additionally, when these persistent cells were placed into growth-promoting conditions, they were able to re-enter the cell cycle and proliferate. These results highlight the potential for either PTEN loss or KRAS activation to promote cell survival in vivo, and the unique ability of the combined mutations to yield rapid tumor growth. This could have important implications in determining recurrence risk and disease progression in tumor subtypes where these mutations are common. PMID:26497685

  11. The combinatorial activation of the PI3K and Ras/MAPK pathways is sufficient for aggressive tumor formation, while individual pathway activation supports cell persistence.

    PubMed

    Thompson, Keyata N; Whipple, Rebecca A; Yoon, Jennifer R; Lipsky, Michael; Charpentier, Monica S; Boggs, Amanda E; Chakrabarti, Kristi R; Bhandary, Lekhana; Hessler, Lindsay K; Martin, Stuart S; Vitolo, Michele I

    2015-11-01

    A high proportion of human tumors maintain activation of both the PI3K and Ras/MAPK pathways. In basal-like breast cancer (BBC), PTEN expression is decreased/lost in over 50% of cases, leading to aberrant activation of the PI3K pathway. Additionally, BBC cell lines and tumor models have been shown to exhibit an oncogenic Ras-like gene transcriptional signature, indicating activation of the Ras/MAPK pathway. To directly test how the PI3K and Ras/MAPK pathways contribute to tumorigenesis, we deleted PTEN and activated KRas within non-tumorigenic MCF-10A breast cells. Neither individual mutation was sufficient to promote tumorigenesis, but the combination promoted robust tumor growth in mice. However, in vivo bioluminescence reveals that each mutation has the ability to promote a persistent phenotype. Inherent in the concept of tumor cell dormancy, a stage in which residual disease is present but remains asymptomatic, viable cells with each individual mutation can persist in vivo during a period of latency. The persistent cells were excised from the mice and showed increased levels of the cell cycle arrest proteins p21 and p27 compared to the aggressively growing PTEN-/-KRAS(G12V) cells. Additionally, when these persistent cells were placed into growth-promoting conditions, they were able to re-enter the cell cycle and proliferate. These results highlight the potential for either PTEN loss or KRAS activation to promote cell survival in vivo, and the unique ability of the combined mutations to yield rapid tumor growth. This could have important implications in determining recurrence risk and disease progression in tumor subtypes where these mutations are common. PMID:26497685

  12. A2B adenosine receptor contributes to penile erection via PI3K/AKT signaling cascade-mediated eNOS activation

    PubMed Central

    Wen, Jiaming; Grenz, Almut; Zhang, Yujin; Dai, Yingbo; Kellems, Rodney E.; Blackburn, Michael R.; Eltzschig, Holger K.; Xia, Yang

    2011-01-01

    Normal penile erection is under the control of multiple factors and signaling pathways. Although adenosine signaling is implicated in normal and abnormal penile erection, the exact role and the underlying mechanism for adenosine signaling in penile physiology remain elusive. Here we report that shear stress leads to increased adenosine release from endothelial cells. Subsequently, we determined that ecto-5′-nucleotidase (CD73) is a key enzyme required for the production of elevated adenosine from ATP released by shear-stressed endothelial cells. Mechanistically, we demonstrate that shear stress-mediated elevated adenosine functions through the adenosine A2B receptor (A2BR) to activate the PI3K/AKT signaling cascade and subsequent increased endothelial nitric oxide synthase (eNOS) phosphorylation. These in vitro studies led us to discover further that adenosine was induced during sustained penile erection and contributes to PI3K/AKT activation and subsequent eNOS phosphorylation via A2BR signaling in intact animal. Finally, we demonstrate that lowering adenosine in wild-type mice or genetic deletion of A2BR in mutant mice significantly attenuated PI3K/AKT activation, eNOS phosphorylation, and subsequent impaired penile erection featured with the reduction of ratio of maximal intracavernosal pressure to systemic arterial pressure from 0.49 ± 0.03 to 0.41 ± 0.05 and 0.38 ± 0.04, respectively (both P<0.05). Overall, using biochemical, cellular, genetic, and physiological approaches, our findings reveal that adenosine is a novel molecule signaling via A2BR activation, contributing to penile erection via PI3K/AKT-dependent eNOS activation. These studies suggest that this signaling pathway may be a novel therapeutic target for erectile disorders.—Wen, J., Grenz, A., Zhang, Y., Dai, Y., Kellems, R. E., Blackburn, M. R., Eltzschig, H. K., Xia, Y. A2B adenosine receptor contributes to penile erection via PI3K/AKT signaling cascade-mediated eNOS activation. PMID

  13. Cytoskeletal rearrangement and Src and PI-3K-dependent Akt activation control GABA(B)R-mediated chemotaxis.

    PubMed

    Barati, Michelle T; Lukenbill, Janice; Wu, Rui; Rane, Madhavi J; Klein, Jon B

    2015-06-01

    The γ-amino butyric acid (GABA) type B receptors (GABA(B)R) function as chemoattractant receptors in response to GABA(B)R agonists in human neutrophils. The goal of this study was to define signaling mechanisms regulating GABA(B)R-mediated chemotaxis and cytoskeletal rearrangement. In a proteomic study we identified serine/threonine kinase Akt, tyrosine kinases Src and Pyk2, microtubule regulator kinesin and microtubule affinity-regulating kinase (MARK) co-immunoprecipitating with GABA(B)R. To define the contributions of these candidate signaling events in GABA(B)R-mediated chemotaxis, we used rat basophilic leukemic cells (RBL-2H3 cells) stably transfected with human GABA(B1b) and GABA(B2) receptors. The GABA(B)R agonist baclofen induced Akt phosphorylation and chemotaxis by binding to its specific GABA(B)R since pretreatment of cells with CGP52432, a GABA(B)R antagonist, blocked such effects. Moreover, baclofen induced Akt phosphorylation was shown to be dependent upon PI-3K and Src kinases. Baclofen failed to stimulate actin polymerization in suspended RBL cells unless exposed to a baclofen gradient. However, baclofen stimulated both actin and tubulin polymerization in adherent RBL-GABA(B)R cells. Blockade of actin and tubulin polymerization by treatment of cells with cytochalasin D or nocodazole respectively, abolished baclofen-mediated chemotaxis. Furthermore, baclofen stimulated Pyk2 and STAT3 phosphorylation, both known regulators of cell migration. In conclusion, GABA(B)R stimulation promotes chemotaxis in RBL cells which is dependent on signaling via PI3-K/Akt, Src kinases and on rearrangement of both microtubules and actin cytoskeleton. These data define mechanisms of GABA(B)R-mediated chemotaxis which may potentially be used to therapeutically regulate cellular response to injury and disease.

  14. Anti-angiogenic activity of macrolactin A and its succinyl derivative is mediated through inhibition of class I PI3K activity and its signaling.

    PubMed

    Kang, Youra; Regmi, Sushil Chandra; Kim, Mi Yeong; Banskota, Suhrid; Gautam, Jaya; Kim, Dong Hee; Kim, Jung-Ae

    2015-02-01

    In the current study, macrolactin compounds, macrolactin A (MA) and 7-O-succinyl macrolactin A (SMA), were investigated for their anti-angiogenic activities and action mechanism. MA and SMA inhibited in vitro and in vivo angiogenesis induced by three different classes of pro-angiogenic factors, VEGF, IL-8, and TNF-α. SMA exhibited stronger anti-angiogenic activity than MA, and such anti-angiogenic activity of SMA was consistently observed in MDA-MB-231 human breast cancer cell-inoculated CAM assay showing dose-dependent suppression of tumor growth and tumor-induced angiogenesis. In an in vitro PI3K competitive activity assay, SMA induced concentration-dependent inhibition of class I PI3K isoforms, p110α, p110β, p110δ, and p110γ. In addition, non-receptor tyrosine kinase c-Src, which is involved in the activation of PI3K heterodimer, was suppressed by MA and SMA. Correspondingly, MA and SMA significantly inhibited the stimulus-induced phosphorylation of Akt, mTOR, p70S6K, and ribosomal S6 in human umbilical vein endothelial cells (HUVECs). At the same time, the stimulus-induced production of reactive oxygen species (ROS) and activation of NF-κB were significantly suppressed by MA and SMA. Moreover, the macrolactins suppressed NF-κB-regulated HSP90 protein expression, which stabilizes phosphorylated Akt and NADPH oxidase. Suppression of NF-κB in macrolactin-treated HUVECs with concurrent inhibition of rS6 indicates that MAs effectively block angiogenesis through down-regulation of genes related to angiogenesis at both transcriptional and translational levels. Taken together, the results demonstrate that anti-angiogenic effect of MA and SMA is mediated through inhibition of PI3K/Akt and NADPH oxidase-derived ROS/NF-κB signaling pathways. These results further indicate that MA and SMA may be applicable for treatment of various diseases associated with angiogenesis.

  15. Interleukin-6-mediated functional upregulation of TRPV1 receptors in dorsal root ganglion neurons through the activation of JAK/PI3K signaling pathway: roles in the development of bone cancer pain in a rat model.

    PubMed

    Fang, Dong; Kong, Ling-Yu; Cai, Jie; Li, Song; Liu, Xiao-Dan; Han, Ji-Sheng; Xing, Guo-Gang

    2015-06-01

    Primary and metastatic cancers that affect bone are frequently associated with severe and intractable pain. The mechanisms underlying the pathogenesis of bone cancer pain still remain largely unknown. Previously, we have reported that sensitization of primary sensory dorsal root ganglion (DRG) neurons contributes to the pathogenesis of bone cancer pain in rats. In addition, numerous preclinical and clinical studies have revealed the pathological roles of interleukin-6 (IL-6) in inflammatory and neuropathic hyperalgesia. In this study, we investigated the role and the underlying mechanisms of IL-6 in the development of bone cancer pain using in vitro and in vivo approaches. We first demonstrated that elevated IL-6 in DRG neurons plays a vital role in the development of nociceptor sensitization and bone cancer-induced pain in a rat model through IL-6/soluble IL-6 receptor (sIL-6R) trans-signaling. Moreover, we revealed that functional upregulation of transient receptor potential vanilloid channel type 1 (TRPV1) in DRG neurons through the activation of Janus kinase (JAK)/phosphatidylinositol 3-kinase (PI3K) signaling pathway contributes to the effects of IL-6 on the pathogenesis of bone cancer pain. Therefore, suppression of functional upregulation of TRPV1 in DRG neurons by the inhibition of JAK/PI3K pathway, either before surgery or after surgery, reduces the hyperexcitability of DRG neurons and pain hyperalgesia in bone cancer rats. We here disclose a novel intracellular pathway, the IL-6/JAK/PI3K/TRPV1 signaling cascade, which may underlie the development of peripheral sensitization and bone cancer-induced pain.

  16. Deuterohemin-AlaHisLys mitigates the symptoms of rats with non-insulin dependent diabetes mellitus by scavenging reactive oxygen species and activating the PI3-K/AKT signal transduction pathway.

    PubMed

    Lei, Liyan; Zhang, Guangji; Li, Pengfei; Zhang, Yuan; Guo, Youming; Zhang, Wenqi; Zhang, Wenbo; Hu, Bing; Wang, Liping

    2014-09-01

    Damage to pancreatic β-cells plays an important role in the development of type 2 diabetes, and oxidative stress is a likely contributor. In the present study, we investigated the effect of deuterohemin-AlaHisLys (DhHP-3), a microperoxidase-11 mimic, on rats with non-insulin dependent diabetes mellitus and examined the action mechanisms of DhHP-3. The induced hyperglycemia, glucose intolerance, and insulin resistance in diabetic rats were associated with increased oxidative stress and damage to pancreatic islets. DhHP-3 (3 mg/kg) ameliorated hyperglycemia and insulin resistance, protected pancreas islet, decreased the content of malondialdehyde, and increased the activity of superoxide dismutase in plasma and pancreatic tissue by reducing ROS levels. Furthermore, DhHP-3 stimulated the proliferation of INS-1 cells and inhibited apoptosis by activating the phosphatidylinositol 3-kinase/protein kinase B (PI3-K/AKT) signaling pathway. Our results demonstrated for the first time that DhHP-3 decreased blood glucose level in rats with non-insulin dependent diabetes mellitus, scavenged reactive oxygen species, activated the PI3-K/AKT signaling pathway, and protected pancreatic β-cells against apoptosis.

  17. COMP-angiopoietin 1 increases proliferation, differentiation, and migration of stem-like cells through Tie-2-mediated activation of p38 MAPK and PI3K/Akt signal transduction pathways

    SciTech Connect

    Kook, Sung-Ho; Lim, Shin-Saeng; Cho, Eui-Sic; Lee, Young-Hoon; Han, Seong-Kyu; Lee, Kyung-Yeol; Kwon, Jungkee; Hwang, Jae-Won; Bae, Cheol-Hyeon; Seo, Young-Kwon; Lee, Jeong-Chae

    2014-12-12

    Highlights: • COMP-Ang1 induces Tie-2 activation in BMMSCs, but not in primary osteoblasts. • Tie-2 knockdown inhibits COMP-Ang1-stimulated proliferation and osteoblastogenesis. • Tie-2 knockdown prevents COMP-Ang1-induced activation of PI3K/Akt and p38 MAPK. • COMP-Ang1 induces migration of cells via activation of PI3K/Akt and CXCR4 pathways. • COMP-Ang1 stimulates in vivo migration of PDLSCs into a calvarial defect site of rats. - Abstract: Recombinant COMP-Ang1, a chimera of angiopoietin-1 (Ang1) and a short coiled-coil domain of cartilage oligomeric matrix protein (COMP), is under consideration as a therapeutic agent capable of inducing the homing of cells with increased angiogenesis. However, the potentials of COMP-Ang1 to stimulate migration of mesenchymal stem cells (MSCs) and the associated mechanisms are not completely understood. We examined the potential of COMP-Ang1 on bone marrow (BM)-MSCs, human periodontal ligament stem cells (PDLSCs), and calvarial osteoblasts. COMP-Ang1 augmented Tie-2 induction at protein and mRNA levels and increased proliferation and expression of runt-related transcription factor 2 (Runx2), osterix, and CXCR4 in BMMSCs, but not in osteoblasts. The COMP-Ang1-mediated increases were inhibited by Tie-2 knockdown and by treating inhibitors of phosphoinositide 3-kinase (PI3K), LY294002, or p38 mitogen-activated protein kinase (MAPK), SB203580. Phosphorylation of p38 MAPK and Akt was prevented by siRNA-mediated silencing of Tie-2. COMP-Ang1 also induced in vitro migration of BMMSCs and PDLSCs. The induced migration was suppressed by Tie-2 knockdown and by CXCR4-specific peptide antagonist or LY294002, but not by SB203580. Furthermore, COMP-Ang1 stimulated the migration of PDLSCs into calvarial defect site of rats. Collectively, our results demonstrate that COMP-Ang1-stimulated proliferation, differentiation, and migration of progenitor cells may involve the Tie-2-mediated activation of p38 MAPK and PI3K/Akt pathways.

  18. 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

  19. 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.

  20. Niacin activates the PI3K/Akt cascade via PKC- and EGFR-transactivation-dependent pathways through hydroxyl-carboxylic acid receptor 2.

    PubMed

    Sun, Huawang; Li, Guo; Zhang, Wenjuan; Zhou, Qi; Yu, Yena; Shi, Ying; Offermanns, Stefan; Lu, Jianxin; Zhou, Naiming

    2014-01-01

    Niacin has been demonstrated to activate a PI3K/Akt signaling cascade to prevent brain damage after stroke and UV-induced skin damage; however, the underlying molecular mechanisms for HCA2-induced Akt activation remain to be elucidated. Using CHO-K1 cells stably expressing HCA2 and A431 cells, a human epidermoid cell line with high levels of endogenous expression of functional HCA2 receptors, we first demonstrated that niacin induced a robust Akt phosphorylation at both Thr308 and Ser473 in a time-dependent fashion, with a maximal activation at 5 min and a subsequent reduction to baseline by 30 min through HCA2, and that the activation was significantly blocked by pertussis toxin. The HCA2-mediated activation of Akt was also significantly inhibited by the PKC inhibitors GF109203x and Go6983 in both cell lines, by the PDGFR-selective inhibitor tyrphostin A9 in CHO-HCA2 cells and by the MMP inhibitor GM6001 and EGFR-specific inhibitor AG1478 in A431 cells. These results suggest that the PKC pathway and PDGFR/EGFR transactivation pathway play important roles in HCA2-mediated Akt activation. Further investigation indicated that PI3K and the Gβγ subunit were likely to play an essential role in HCA2-induced Akt activation. Moreover, Immunobloting analyses using an antibody that recognizes p70S6K1 phosphorylated at Thr389 showed that niacin evoked p70S6K1 activation via the PI3K/Akt pathway. The results of our study provide new insight into the signaling pathways involved in HCA2 activation.

  1. Honokiol and magnolol stimulate glucose uptake by activating PI3K-dependent Akt in L6 myotubes.

    PubMed

    Choi, Sun-Sil; Cha, Byung-Yoon; Lee, Young-Sil; Yonezawa, Takayuki; Teruya, Toshiaki; Nagai, Kazuo; Woo, Je-Tae

    2012-01-01

    Honokiol and magnolol, ingredients of Magnolia officinalis, which is used in traditional Chinese and Japanese medicines, have been reported to have antioxidant, anticancer, and antiangiogenic effects. Effects of these compounds on glucose metabolism in adipocytes have also been reported. However, their effects on skeletal muscle glucose uptake and the underlying molecular mechanisms are still unknown. Here, we investigated the direct effects and signaling pathways activated by honokiol and magnolol in skeletal muscle cells using L6 myotubes. We found that honokiol and magnolol dose-dependently acutely stimulated glucose uptake without synergistic effects of combined administration in L6 myotubes. Treatment with honokiol and magnolol also stimulated glucose transporter-4 translocation to the cell surface. Honokiol- and magnolol-stimulated glucose uptake was blocked by the phosphatidylinositol-3 kinase inhibitor, wortmannin. Both honokiol and magnolol stimulated Akt phosphorylation, a key element in the insulin signaling pathway, which was completely inhibited by wortmannin. These results suggest that honokiol and magnolol might have beneficial effects on glucose metabolism by activating the insulin signaling pathway. PMID:22674833

  2. Sustained PI3K Activation exacerbates BLM-induced Lung Fibrosis via activation of pro-inflammatory and pro-fibrotic pathways

    PubMed Central

    Kral, Julia Barbara; Kuttke, Mario; Schrottmaier, Waltraud Cornelia; Birnecker, Birgit; Warszawska, Joanna; Wernig, Christina; Paar, Hannah; Salzmann, Manuel; Sahin, Emine; Brunner, Julia Stefanie; Österreicher, Christoph; Knapp, Sylvia; Assinger, Alice; Schabbauer, Gernot

    2016-01-01

    Idiopathic pulmonary fibrosis (IPF) is a life-threatening disease with limited treatment options. Additionally, the lack of a complete understanding of underlying immunological mechanisms underscores the importance of discovering novel options for therapeutic intervention. Since the PI3K/PTEN pathway in myeloid cells influences their effector functions, we wanted to elucidate how sustained PI3K activity induced by cell-type specific genetic deficiency of its antagonist PTEN modulates IPF, in a murine model of bleomycin-induced pulmonary fibrosis (BIPF). We found that myeloid PTEN deficient mice (PTENMyKO), after induction of BIPF, exhibit increased TGF-β1 activation, mRNA expression of pro-collagens and lysyl oxidase as well as augmented collagen deposition compared to wild-type littermates, leading to enhanced morbidity and decreased survival. Analysis of alveolar lavage and lung cell composition revealed that PTENMyKO mice exhibit reduced numbers of macrophages and T-cells in response to bleomycin, indicating an impaired recruitment function. Interestingly, we found dysregulated macrophage polarization as well as elevated expression and release of the pro-fibrotic cytokines IL-6 and TNF-α in PTENMyKO mice during BIPF. This might point to an uncontrolled wound healing response in which the inflammatory as well as tissue repair mechanisms proceed in parallel, thereby preventing resolution and at the same time promoting extensive fibrosis. PMID:26971883

  3. Agmatine Reduces Lipopolysaccharide-Mediated Oxidant Response via Activating PI3K/Akt Pathway and Up-Regulating Nrf2 and HO-1 Expression in Macrophages

    PubMed Central

    Chai, Jianshen; Luo, Li; Hou, Fengyan; Fan, Xia; Yu, Jing; Ma, Wei; Tang, Wangqi; Yang, Xue; Zhu, Junyu; Kang, Wenyuan; Yan, Jun; Liang, Huaping

    2016-01-01

    Macrophages are key responders of inflammation and are closely related with oxidative stress. Activated macrophages can enhance oxygen depletion, which causes an overproduction of reactive oxygen species (ROS) and leads to further excessive inflammatory response and tissue damage. Agmatine, an endogenous metabolite of L-arginine, has recently been shown to have neuroprotective effects based on its antioxidant properties. However, the antioxidant effects of agmatine in peripheral tissues and cells, especially macrophages, remain unclear. In this study we explored the role of agmatine in mediating antioxidant effects in RAW 264.7 cells and studied its antioxidant mechanism. Our data demonstrate that agmatine is an activator of Nrf2 signaling that markedly enhances Nrf2 nuclear translocation, increases nuclear Nrf2 protein level, up-regulates the expression of the Nrf2 downstream effector HO-1, and attenuates ROS generation induced by Lipopolysaccharide (LPS). We further demonstrated that the agmatine-induced activation of Nrf2 is likely through the PI3K/Akt pathway. LY294002, a specific PI3K/Akt inhibitor, abolished agmatine-induced HO-1 up-regulation and ROS suppression significantly. Inhibiting HO-1 pathway significantly attenuated the antioxidant effect of agmatine which the products of HO-1 enzymatic activity contributed to. Furthermore, the common membrane receptors of agmatine were evaluated, revealing that α2-adrenoceptor, I1-imidazoline receptor or I2-imidazoline receptor are not required by the antioxidant properties of agmatine. Taken together, our findings revealed that agmatine has antioxidant activity against LPS-induced ROS accumulation in RAW 264.7 cells involving HO-1 expression induced by Nrf2 via PI3K/Akt pathway activation. PMID:27685463

  4. 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

  5. Centipedegrass extract induces apoptosis through the activation of caspases and the downregulation of PI3K/Akt and MAPK phosphorylation in leukemia cells.

    PubMed

    Bai, Hyoung-Woo; Badaboina, Srilatha; Park, Chul-Hong; Choi, Bo Yun; Na, Yun Hee; Chung, Byung Yeoup

    2015-02-01

    Acute lymphoblastic leukemia (ALL), which involves the blood and bone marrow, is the most common type of cancer in children younger than 5 years of age. Previous studies have investigated the effects of centipedegrass extract (CGE), which is mainly composed of maysin and its derivatives, and have demonstrated that it has various biological activities, including antioxidant and anti‑inflammatory activities, pancreatic lipase inhibitory activity, anti-adipogenic activity and insecticidal activity. To the best of our knowledge, this study is the first to investigate the anticancer effects of CGE in ALL cell lines and to elucidate the mechanisms underlying these effects. Cell viability was measured by thiazolyl blue tetrazolium blue (MTT) assay. Apoptosis, cell cycle progression and mitochondrial membrane potential (∆Ψm) were determined by flow cytometry. The effects of CGE on the phosphatidylinositol 3‑kinase (PI3K)/Akt pathway and mitogen‑activated protein kinases (MAPKs) were assessed by immunoblotting. PI3K, MAPK and caspase inhibitors were used to further confirm the molecular mechanisms involved. Our results clearly demonstrated that the proliferation of the ALL cells was significantly inhibited by CGE in a dose‑dependent manner. Apoptosis was accompanied by the induction of significant G1 cell cycle arrest. The resulting alteration of the ∆Ψm increased the activity of caspase‑3/7. The induction of apoptosis was enhanced by the combined treatment of CGE with a PI3K inhibitor or an extracellular signal-regulated kinase (ERK) inhibitor, whereas the CGE‑induced apoptosis was inhibited in the presence of caspase inhibitors, such as z‑VAD‑fmk and z‑IETD‑fmk. Furthermore, CGE inhibited PI3K activity by decreasing the levels of phosphorylated (p‑)Akt, p‑BAD, and Bcl‑2 together with the levels of MAPKs, including p‑ERK and p‑JNK, but demonstrated no effects on p38 MAPK. Thus, our data suggest that CGE may be a novel natural

  6. Subtle distinct regulations of late erythroid molecular events by PI3K/AKT-mediated activation of Spi-1/PU.1 oncogene autoregulation loop.

    PubMed

    Breig, O; Théoleyre, O; Douablin, A; Baklouti, F

    2010-05-13

    Spi-1/PU.1 oncogene is downregulated as proerythroblasts undergo terminal differentiation. Insertion of the Friend virus upstream of the Spi-1/PU.1 locus leads to the constitutive upregulation of Spi-1/PU.1, and a subsequent block in the differentiation of the affected erythroblasts. We have shown that sustained overexpression of Spi-1/PU.1 also inhibits the erythroid splicing of protein 4.1R exon 16, irrespective of chemical induction of differentiation. Here, we show a positive feedback loop that couples constitutive phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling to high expression of Spi-1/PU.1 in Friend erythroleukemia cells. Inhibition of PI3K/AKT results in Spi-1/PU.1 downregulation in a stepwise manner and induces cell differentiation. Chromatin immunoprecipitation assays further supported the positive autoregulatory effect of Spi-1/PU.1. Mutational analysis indicated that Ser41, but not Ser148, is necessary for Spi-1/PU.1-mediated repression of hemoglobin expression, whereas both Ser residues are required for Spi-1/PU.1 inhibition of the erythroid splicing event. We further show that inhibition of the erythroid transcriptional and splicing events are strictly dependent on distinct Spi-1/PU.1 phosphorylation modifications rather than Spi-1/PU.1 expression level per se. Our data further support the fact that Spi-1/PU.1 inhibits 4.1R erythroid splicing through two different pathways, and bring new insights into the extracellular signal impact triggered by erythropoietin on late erythroid regulatory program, including pre-mRNA splicing.

  7. Auranofin-mediated inhibition of PI3K/AKT/mTOR axis and anticancer activity in non-small cell lung cancer cells

    PubMed Central

    Li, Hongyu; Hu, Jing; Wu, Shuhong; Wang, Li; Cao, Xiaobo; Zhang, Xiaoshan; Dai, Bingbing; Cao, Mengru; Shao, Ruping; Zhang, Ran; Majidi, Mourad; Ji, Lin; Heymach, John V.; Wang, Michael; Pan, Shiyang; Minna, John; Mehran, Reza J.; Swisher, Stephen G.; Roth, Jack A.; Fang, Bingliang

    2016-01-01

    Auranofin, a gold complex that has been used to treat rheumatoid arthritis in clinics and has documented pharmacokinetic and safety profiles in humans, has recently been investigated for its anticancer activity in leukemia and some solid cancers. However, auranofin's single agent activity in lung cancer is not well characterized. To determine whether auranofin has single agent activity in lung cancer, we evaluated auranofin's activity in a panel of 10 non-small cell lung cancer (NSCLC) cell lines. Cell viability analysis revealed that auranofin induced growth inhibition in a subset of NSCLC cell lines with a half maximal inhibitory concentration (IC50) below 1.0 μM. Treatment with auranofin elicited apoptosis and necroptosis in auranofin-sensitive cell lines. Moreover, the susceptibility of NSCLC cells to auranofin was inversely correlated with TXNRD1 expression in the cells. Transient transfection of the TXNRD1-expressing plasmid in auranofin-sensitive Calu3 cells resulted in partial resistance, indicating that high TXNRD level is one of causal factors for resistance to auranofin. Further mechanistic characterization with proteomic analysis revealed that auranofin inhibits expression and/or phosphorylation of multiple key nodes in the PI3K/AKT/mTOR pathway, including S6, 4EBP1, Rictor, p70S6K, mTOR, TSC2, AKT and GSK3. Ectopic expression of TXNRD1 partially reversed auranofin-mediated PI3K/AKT/mTOR inhibition, suggesting that TXNRD1 may participate in the regulation of PI3K/AKT/mTOR pathway. Administration of auranofin to mice with xenograft tumors derived from NSCLC cells significantly suppressed tumor growth without inducing obvious toxic effects. Our results demonstrated feasibility of repurposing auranofin for treatment of lung cancer. PMID:26657290

  8. Auranofin-mediated inhibition of PI3K/AKT/mTOR axis and anticancer activity in non-small cell lung cancer cells.

    PubMed

    Li, Hongyu; Hu, Jing; Wu, Shuhong; Wang, Li; Cao, Xiaobo; Zhang, Xiaoshan; Dai, Bingbing; Cao, Mengru; Shao, Ruping; Zhang, Ran; Majidi, Mourad; Ji, Lin; Heymach, John V; Wang, Michael; Pan, Shiyang; Minna, John; Mehran, Reza J; Swisher, Stephen G; Roth, Jack A; Fang, Bingliang

    2016-01-19

    Auranofin, a gold complex that has been used to treat rheumatoid arthritis in clinics and has documented pharmacokinetic and safety profiles in humans, has recently been investigated for its anticancer activity in leukemia and some solid cancers. However, auranofin's single agent activity in lung cancer is not well characterized. To determine whether auranofin has single agent activity in lung cancer, we evaluated auranofin's activity in a panel of 10 non-small cell lung cancer (NSCLC) cell lines. Cell viability analysis revealed that auranofin induced growth inhibition in a subset of NSCLC cell lines with a half maximal inhibitory concentration (IC50) below 1.0 μM. Treatment with auranofin elicited apoptosis and necroptosis in auranofin-sensitive cell lines. Moreover, the susceptibility of NSCLC cells to auranofin was inversely correlated with TXNRD1 expression in the cells. Transient transfection of the TXNRD1-expressing plasmid in auranofin-sensitive Calu3 cells resulted in partial resistance, indicating that high TXNRD level is one of causal factors for resistance to auranofin. Further mechanistic characterization with proteomic analysis revealed that auranofin inhibits expression and/or phosphorylation of multiple key nodes in the PI3K/AKT/mTOR pathway, including S6, 4EBP1, Rictor, p70S6K, mTOR, TSC2, AKT and GSK3. Ectopic expression of TXNRD1 partially reversed auranofin-mediated PI3K/AKT/mTOR inhibition, suggesting that TXNRD1 may participate in the regulation of PI3K/AKT/mTOR pathway. Administration of auranofin to mice with xenograft tumors derived from NSCLC cells significantly suppressed tumor growth without inducing obvious toxic effects. Our results demonstrated feasibility of repurposing auranofin for treatment of lung cancer. PMID:26657290

  9. 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.

  10. Anastrozole and everolimus in advanced gynecologic and breast malignancies: activity and molecular alterations in the PI3K/AKT/mTOR pathway

    PubMed Central

    Wheler, Jennifer J.; Moulder, Stacy L.; Naing, Aung; Janku, Filip; Piha-Paul, Sarina A.; Falchook, Gerald S.; Zinner, Ralph; Tsimberidou, Apostolia M.; Fu, Siqing; Hong, David S.; Atkins, Johnique T.; Yelensky, Roman; Stephens, Philip J.; Kurzrock, Razelle

    2014-01-01

    Background: Since PI3K/AKT/mTOR pathway activation diminishes the effects of hormone therapy, combining aromatase inhibitors (anatrozole) with mTOR inhibitors (everolimus) was investigated. Patients and Methods: We evaluated anastrozole and everolimus in 55 patients with metastatic estrogen (ER) and/or progesterone receptor (PR)-positive breast and gynecologic tumors. Endpoints were safety, antitumor activity and molecular correlates. Results: Full doses of anastrozole (1 mg PO daily) and everolimus (10 mg PO daily) were well tolerated. Twelve of 50 evaluable patients (24%) (median = 3 prior therapies) achieved stable disease (SD) ≥ 6 months/partial response (PR)/complete response (CR) (n = 5 (10%) with PR/CR): 9 of 32 (28%) with breast cancer (n=5 (16%) with PR/CR); 2 of 10 (20%), ovarian cancer; and 1 of 6 (17%), endometrial cancer. Six of 22 patients (27%) with molecular alterations in the PI3K/AKT/mTOR pathway achieved SD ≥ 6 months/PR/CR. Six of 8 patients (75%) with SD ≥ 6 months/PR/CR with molecular testing demonstrated at least one alteration in the PI3K/AKT/mTOR pathway: mutations in PIK3CA (n=3) and AKT1 (n=1) or PTEN loss (n=3). All three responders (CR (n = 1); PR (n=2)) who had next generation sequencing demonstrated additional alterations: amplifications in CCNE1, IRS2, MCL1, CCND1, FGFR1 and MYC and a rearrangement in PRKDC. Conclusions: Combination anastrozole and everolimus is well tolerated at full approved doses, and is active in heavily-pretreated patients with ER and/or PR-positive breast, ovarian and endometrial cancers. Responses were observed in patients with multiple molecular aberrations. Clinical Trails Included: NCT01197170 PMID:24912489

  11. Loss of Mel-18 induces tumor angiogenesis through enhancing the activity and expression of HIF-1α mediated by the PTEN/PI3K/Akt pathway.

    PubMed

    Park, J H; Lee, J Y; Shin, D H; Jang, K S; Kim, H J; Kong, Gu

    2011-11-10

    Mel-18 has been implicated in several processes in tumor progression, in which the Akt pathway is involved as an important key molecular event. However, the function of Mel-18 in human cancers has not been fully established yet. Here, we examined the effect of Mel-18 on tumor angiogenesis in human breast cancer, and found that Mel-18 was a novel regulator of HIF-1α. Mel-18 negatively regulated the HIF-1α expression and its target gene VEGF transcription during both normoxia and hypoxia. We demonstrated that Mel-18 regulated the HIF-1α expression and activity via the PI3K/Akt pathway. Loss of Mel-18 downregulated Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) expression, consequently activating the PI3K/Akt/MDM2 pathway, and leading to an increase of HIF-1α protein level. Mel-18 modulated the HIF-1α transcriptional activity via regulating the cytoplasmic retention of FOXO3a, a downstream effector of Akt, and recruitment of HIF-1α/CBP complex to the VEGF promoter. Furthermore, our data shows that Mel-18 blocked tumor angiogenesis both in vitro and in vivo. Mel-18 overexpression inhibited in vitro tube formation in human umbilical endothelial cells (HUVECs). Xenografts in NOD/SCID mice derived from stably Mel-18 knocked down MCF7 human breast cancer cells showed increased tumor volume, microvessel density, and phospho-Akt and HIF-1α expression levels. In conclusion, our findings provide that Mel-18 is a novel regulator of tumor angiogenesis through regulating HIF-1α and its target VEGF expressions mediated by the PTEN/PI3K/Akt pathway, suggesting a new tumor-suppressive role of Mel-18 in human breast cancer.

  12. IL-7 splicing variant IL-7{delta}5 induces human breast cancer cell proliferation via activation of PI3K/Akt pathway

    SciTech Connect

    Pan, Deshun; Liu, Bing; Jin, Xiaobao; Zhu, Jiayong

    2012-06-15

    Highlights: Black-Right-Pointing-Pointer This study confirms the role of IL-7{delta}5 in breast cancer cell proliferation. Black-Right-Pointing-Pointer IL-7{delta}5 promotes breast cancer cell proliferation and cell cycle progression. Black-Right-Pointing-Pointer IL-7{delta}5 promotes cell proliferation via activation of PI3K/Akt pathway. -- Abstract: Various tumor cells express interleukin 7 (IL-7) and IL-7 variants. IL-7 has been confirmed to stimulate solid tumor cell proliferation. However, the effect of IL-7 variants on tumor cell proliferation remains unclear. In this study, we evaluated the role of IL-7{delta}5 (an IL-7 variant lacking exon 5) on proliferation and cell cycle progression of human MDA-MB-231 and MCF-7 breast cancer cells. The results showed that IL-7{delta}5 promoted cell proliferation and cell cycle progression from G1 phase to G2/M phase, associated with upregulation of cyclin D1 expression and the downregulation of p27{sup kip1} expression. Mechanistically, we found that IL-7{delta}5 induced the activation of Akt. Inhibition of PI3K/Akt pathway by LY294002 reversed the proliferation and cell cycle progression of MDA-MB-231 and MCF-7 cells induced by IL-7{delta}5. In conclusion, our findings demonstrate that IL-7{delta}5 variant induces human breast cancer cell proliferation and cell cycle progression via activation of PI3K/Akt pathway. Thus, IL-7{delta}5 may be a potential target for human breast cancer therapeutics intervention.

  13. 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

  14. MALAT1 promotes the proliferation and metastasis of osteosarcoma cells by activating the PI3K/Akt pathway.

    PubMed

    Dong, Yongqiang; Liang, Guojun; Yuan, Bo; Yang, Chaoqun; Gao, Rui; Zhou, Xuhui

    2015-03-01

    Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), one of the first found cancer-associated long noncoding RNAs (lncRNAs), involves in the development and progression of many types of tumors. An aberrant expression of MALAT1 was observed in hepatocellular carcinoma, cervical cancer, breast cancer, ovarian cancer, and colorectal cancer. However, the exact effects and molecular mechanisms of MALAT1 in osteosarcoma progression are still unknown up to now. Here, we investigated the role of MALAT1 in human osteosarcoma cell lines and clinical tumor samples in order to determine the function of this molecule. In our research, the MALAT1 messenger RNA (mRNA) was highly expressed in human osteosarcoma tissues, and its expression level was closely correlated with pulmonary metastasis. Then, we employed lentivirus-mediated knockdown of MALAT1 in U-2 OS and SaO2 to determine the role of MALAT1 in osteosarcoma cell lines. Lentivirus-mediated MALAT1 small interfering RNA (siRNA) could efficiently downregulated the expression level of MALAT1 in osteosarcoma cell lines. Knockdown of MALAT1 inhibited the proliferation and invasion of human osteosarcoma cell and suppressed its metastasis in vitro and vivo. At the same time, the proliferating cell nuclear antigen (PCNA), matrix metallopeptidase 9 (MMP-9), phosphorylated PI3Kp85α, and Akt expressions were significantly inhibited in MALAT1-deleted cells. These findings indicated that MALAT1 might suppress the tumor growth and metastasis via PI3K/AKT signaling pathway. Taken together, our data indicated that MALAT1 might be an oncogenic lncRNA that promoted proliferation and metastasis of osteosarcoma and could be regarded as a therapeutic target in human osteosarcoma.

  15. Dixdc1 targets CyclinD1 and p21 via PI3K pathway activation to promote Schwann cell proliferation after sciatic nerve crush.

    PubMed

    Wu, Weijie; Liu, Qingqing; Liu, Yuxi; Yu, Zhaohui; Wang, Youhua

    2016-09-16

    Dixdc1 (DIX domain containing-1), the mammalian homolog of Ccd1 (Coiled-coil-Dishevelled-Axin1), is a protein containing a coiled-coil domain and a Dishevelled-Axin (DIX) domain. As a novel component of the Wnt pathway, Dixdc1 has been reported to be able to promote neural progenitor proliferation and neuronal differentiation via Wnt/β-catenin signaling. But there still remains something unknown about Dixdc1 distribution and functions in the lesion and regeneration of the peripheral nervous system (PNS), so we tried to investigate dynamic changes of Dixdc1 expression in a rat sciatic nerve crush (SNC) model in this study. First of all, we detected SNC-induced increased levels of Dixdc1 in Schwann cells and interestingly identified parallel expression of PCNA (proliferation cell nuclear antigen) with Dixdc1. Besides, we observed up-regulated Dixdc1 during the process of TNF-α-induced Schwann cell proliferation. Also, we discovered that Dixdc1 could promote G1-S phase transition accompanied with the up-regulation of CyclinD1 and down-regulation of p21. More importantly, enhanced effects of Dixdc1 on cell proliferation were confirmed to be associated with PI3K activation. Not only blocking of the PI3K but Dixdc1 knockdown led to significantly decreased ability for proliferation, as well as down-regulation of CyclinD1 and up-regulation of p21. In summary, these data demonstrated that Dixdc1 might participate in Schwann cell proliferation by targeting CyclinD1 and p21 at least partially through the PI3K/AKT activation. PMID:27521891

  16. Methylophiopogonanone A suppresses ischemia/reperfusion-induced myocardial apoptosis in mice via activating PI3K/Akt/eNOS signaling pathway

    PubMed Central

    He, Fei; Xu, Bang-long; Chen, Cai; Jia, Hong-jing; Wu, Ji-xiong; Wang, Xiao-chen; Sheng, Jian-long; Huang, Li; Cheng, Jing

    2016-01-01

    Aim: The dried tuber root of Ophiopogon japonicus has been used in the traditional Chinese medicine for treatment of myocardial ischemia and thrombosis. In this study we investigated the effects of methylophiopogonanone A (MO-A), a major homoisoflavonoid in Ophiopogon japonicus, on myocardial ischemia/reperfusion (I/R) injury. Methods: Mice were pretreated with MO-A (10 mg·kg-1·d-1, po) for 2 weeks and then subjected to transient occlusion of the left anterior descending coronary artery. Cardiac function was evaluated, and the infarct size and apoptosis index were assessed. The mechanisms underlying the cardio-protection of MO-A were analyzed in H9C2 rat cardiomyocytes subjected to hypoxia/reoxygenation (H/R). The cell viability and apoptosis were evaluated; apoptotic and relevant signaling proteins were analyzed. NO levels in the culture medium were assessed. Results: In I/R mice, pretreatment with MO-A significantly reduced the infarct size (by 60.7%) and myocardial apoptosis (by 56.8%), and improved cardiac function. In H9C2 cells subjected to H/R, pretreatment with MO-A (10 μmol/L) significantly decreased apoptosis and cleaved caspase-3 expression, elevated the Bcl-2/Bax ratio and restored NO production. Furthermore, pretreatment with MO-A markedly increased the activation of PI3K/Akt/eNOS pathway in H9C2 cells subjected to H/R, and the protective effects of MO-A were abolished in the presence of the PI3K inhibitor wortmannin (100 nmol/L). Conclusion: MO-A attenuates I/R-induced myocardial apoptosis in mice via activating the PI3K/Akt/eNOS signaling pathway. PMID:27063216

  17. Triiodothyronine (T3) induces proinsulin gene expression by activating PI3K: possible roles for GSK-3β and the transcriptional factor PDX-1.

    PubMed

    Goulart-Silva, F; Serrano-Nascimento, C; Texeira, S S; Nunes, M T

    2013-01-01

    Thyroid hormone (TH) activates PI3K and Akt, leading to glucose uptake in rat skeletal muscle cells and proliferation of insulinoma cells, respectively. However, TH actions on pancreatic beta cells have been little explored, which lead us to evaluate the TH eff ects on proinsulin gene expression, and the involvement of PI3K/Akt/GSK-3β signaling pathway, and a transcriptional factor for insulin (PDX-1). INS-1E cells were sorted into 3 groups: control and TH-depleted treated or not with T3 for 30 min. Cells were also previously treated with actinomycin D (ActD), cycloheximide (CHX), wortmannin or Akt inhibitor. Proinsulin mRNA expression was evaluated by real time PCR, and pGSK-3β and PDX-1 protein content was analyzed by Western blotting. TH depletion decreased proinsulin mRNA content, which was restored after acute T3 treatment. ActD, CHX and wortmannin, but not Akt inhibitor, prevented the rapid stimulatory eff ect of T3 on proinsulin mRNA expression. TH depletion did not affect the phosphorylated GSK-3β and PDX-1 protein content; but T3 treatment led to an increase in the content of these proteins. These data indicate that T3 acutely increases proinsulin mRNA expression, by mechanisms which depends on the activation of PI3K, but not of Akt, and may involve the inactivation of GSK-3β by phosphorylation. Since GSK-3β enhances PDX-1 degradation rate, the GSK-3β inactivation could explain the increase of PDX-1 content in T3-treated cells. Considering that PDX-1 is one of the most important transcriptional factors for proinsulin gene expression, its enhancement may underlie the increased proinsulin mRNA content acutely induced by T3.

  18. Osseointegration of chitosan coated porous titanium alloy implant by reactive oxygen species-mediated activation of the PI3K/AKT pathway under diabetic conditions.

    PubMed

    Li, Xiang; Ma, Xiang-Yu; Feng, Ya-Fei; Ma, Zhen-Sheng; Wang, Jian; Ma, Tian-Cheng; Qi, Wei; Lei, Wei; Wang, Lin

    2015-01-01

    Chitosan coated porous titanium alloy implant (CTI) is demonstrated a promising approach to improve osseointegration capacity of pure porous titanium alloy implant (TI). Since chitosan has been demonstrated to exhibit antioxidant activity, we propose CTI may ameliorate the ROS overproduction, thus reverse the poor osseointegration under diabetic conditions, and investigate the underlying mechanisms. Primary rat osteoblasts incubated on the TI and the CTI were subjected to normal serum (NS), diabetic serum (DS), DS + NAC (a potent ROS inhibitor) and DS + LY294002 (a PI3K/AKT-specific inhibitor). In vivo study was performed on diabetic sheep implanted with TI or CTI into the bone defects on crista iliaca. Results showed that diabetes-induced ROS overproduction led to osteoblast dysfunction and apoptosis, concomitant with the inhibition of AKT in osteoblasts on the TI substrate. While CTI stimulated AKT phosphorylation through ROS attenuation, thus reversed osteoblast dysfunction evidenced by improved osteoblast adhesion, increased proliferation and ALP activity, and decreased cytotoxicity and apoptotic rate, which exerted same effect to NAC treatment on the TI. These effects were further confirmed by the improved osseointegration within the CTI in vivo evidenced by Micro-CT and histological examinations. In addition, the aforementioned promotive effects afforded by CTI were abolished by blocking PI3K/AKT pathway with addition of LY294002. These results demonstrate that the chitosan coating markedly ameliorates diabetes-induced impaired bio-performance of TI via ROS-mediated reactivation of PI3K/AKT pathway, which elicits a new surface functionalization strategy for better clinical performance of titanium implant in diabetic patients.

  19. Reactive oxygen species mediate Cr(VI)-induced carcinogenesis through PI3K/AKT-dependent activation of GSK-3β/β-catenin signaling

    SciTech Connect

    Son, Young-Ok; Pratheeshkumar, Poyil; Wang, Lei; Wang, Xin; Fan, Jia; Kim, Dong-Hern; Lee, Ju-Yeon; Zhang, Zhuo; Lee, Jeong-Chae; Shi, Xianglin

    2013-09-01

    Cr(VI) compounds are known human carcinogens that primarily target the lungs. Cr(VI) produces reactive oxygen species (ROS), but the exact effects of ROS on the signaling molecules involved in Cr(VI)-induced carcinogenesis have not been extensively studied. Chronic exposure of human bronchial epithelial cells to Cr(VI) at nanomolar concentrations (10–100 nM) for 3 months not only induced cell transformation, but also increased the potential of these cells to invade and migrate. Injection of Cr(VI)-stimulated cells into nude mice resulted in the formation of tumors. Chronic exposure to Cr(VI) increased levels of intracellular ROS and antiapoptotic proteins. Transfection with catalase or superoxide dismutase (SOD) prevented Cr(VI)-mediated increases in colony formation, cell invasion, migration, and xenograft tumors. While chronic Cr(VI) exposure led to activation of signaling cascades involving PI3K/AKT/GSK-3β/β-catenin and PI3K/AKT/mTOR, transfection with catalase or SOD markedly inhibited Cr(VI)-mediated activation of these signaling proteins. Inhibitors specific for AKT or β-catenin almost completely suppressed the Cr(VI)-mediated increase in total and active β-catenin proteins and colony formation. In particular, Cr(VI) suppressed autophagy of epithelial cells under nutrition deprivation. Furthermore, there was a marked induction of AKT, GSK-3β, β-catenin, mTOR, and carcinogenic markers in tumor tissues formed in mice after injection with Cr(VI)-stimulated cells. Collectively, our findings suggest that ROS is a key mediator of Cr(VI)-induced carcinogenesis through the activation of PI3K/AKT-dependent GSK-3β/β-catenin signaling and the promotion of cell survival mechanisms via the inhibition of apoptosis and autophagy. - Highlights: • Chronic exposure to Cr(VI) induces carcinogenic properties in BEAS-2B cells. • ROS play an important role in Cr(VI)-induced tumorigenicity of BEAS-2B cells. • PI3K/AKT/GSK-3β/β-catenin signaling involved in Cr

  20. 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

  1. 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

  2. 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

  3. 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.

  4. Induction of metastatic potential by TrkB via activation of IL6/JAK2/STAT3 and PI3K/AKT signaling in breast cancer.

    PubMed

    Kim, Min Soo; Lee, Won Sung; Jeong, Joon; Kim, Seong-Jin; Jin, Wook

    2015-11-24

    In metastatic breast cancers, the acquisition of metastatic ability, which leads to clinically incurable disease and poor survival, has been associated with acquisition of epithelial-mesenchymal transition (EMT) program and self-renewing trait (CSCs) via activation of PI3K/AKT and IL6/JAK2/STAT3 signaling pathways. We found that TrkB is a key regulator of PI3K/AKT and JAK/STAT signal pathway-mediated tumor metastasis and EMT program. Here, we demonstrated that TrkB activates AKT by directly binding to c-Src, leading to increased proliferation. Also, TrkB increases Twist-1 and Twist-2 expression through activation of JAK2/STAT3 by inducing c-Src-JAK2 complex formation. Furthermore, TrkB in the absence of c-Src binds directly to JAK2 and inhibits SOCS3-mediated JAK2 degradation, resulting in increased total JAK2 and STAT3 levels, which subsequently leads to JAK2/STAT3 activation and Twist-1 upregulation. Additionally, activation of the JAK2/STAT3 pathway via induction of IL-6 secretion by TrkB enables induction of activation of the EMT program via induction of STAT3 nuclear translocation. These observations suggest that TrkB is a promising target for future intervention strategies to prevent tumor metastasis, EMT program and self-renewing trait in breast cancer. PMID:26515594

  5. Absence of both Sos-1 and Sos-2 in peripheral CD4(+) T cells leads to PI3K pathway activation and defects in migration.

    PubMed

    Guittard, Geoffrey; Kortum, Robert L; Balagopalan, Lakshmi; Çuburu, Nicolas; Nguyen, Phan; Sommers, Connie L; Samelson, Lawrence E

    2015-08-01

    Sos-1 and Sos-2 are ubiquitously expressed Ras-guanine exchange factors involved in Erk-MAP kinase pathway activation. Using mice lacking genes encoding Sos-1 and Sos-2, we evaluated the role of these proteins in peripheral T-cell signaling and function. Our results confirmed that TCR-mediated Erk activation in peripheral CD4(+) T cells does not depend on Sos-1 and Sos-2, although IL-2-mediated Erk activation does. Unexpectedly, however, we show an increase in AKT phosphorylation in Sos-1/2dKO CD4(+) T cells upon TCR and IL-2 stimulation. Activation of AKT was likely a consequence of increased recruitment of PI3K to Grb2 upon TCR and/or IL-2 stimulation in Sos-1/2dKO CD4(+) T cells. The increased activity of the PI3K/AKT pathway led to downregulation of the surface receptor CD62L in Sos-1/2dKO T cells and a subsequent impairment in T-cell migration.

  6. Mild caloric restriction reduces blood pressure and activates endothelial AMPK-PI3K-Akt-eNOS pathway in obese Zucker rats.

    PubMed

    García-Prieto, C F; Pulido-Olmo, H; Ruiz-Hurtado, G; Gil-Ortega, M; Aranguez, I; Rubio, M A; Ruiz-Gayo, M; Somoza, B; Fernández-Alfonso, M S

    2015-01-01

    Genetic obesity models exhibit endothelial dysfunction associated to adenosine monophosphate-activated protein kinase (AMPK) dysregulation. This study aims to assess if mild short-term caloric restriction (CR) restores endothelial AMPK activity leading to an improvement in endothelial function. Twelve-week old Zucker lean and obese (fa/fa) male rats had access to standard chow either ad libitum (AL, n=8) or 80% of AL (CR, n=8) for two weeks. Systolic blood pressure was significantly higher in fa/fa AL rats versus lean AL animals, but was normalized by CR. Endothelium-dependent relaxation to acetylcholine (ACh, 10(-9) to 10(-4) M) was reduced in fa/fa AL compared to control lean AL rats (p<0.001), and restored by CR. The AMPK activator AICAR (10(-5) to 8·10(-3) M) elicited a lower relaxation in fa/fa AL rings that was normalized by CR (p<0.001). Inhibition of PI3K (wortmannin, 10(-7) M), Akt (triciribine, 10(-5) M), or eNOS (L-NAME, 10(-4) M) markedly reduced AICAR-induced relaxation in lean AL, but not in fa/fa AL rats. These inhibitions were restored by CR in Zucker fa/fa rings. These data show that mild short-term CR improves endothelial function and lowers blood pressure in obesity due to the activation of the AMPK-PI3K-Akt-eNOS pathway. PMID:25530153

  7. Dehydroepiandrosterone ameliorates H2O2-induced Leydig cells oxidation damage and apoptosis through inhibition of ROS production and activation of PI3K/Akt pathways.

    PubMed

    Ding, Xiao; Wang, Dian; Li, Longlong; Ma, Haitian

    2016-01-01

    Dehydroepiandrosterone (DHEA) is widely used as a nutritional supplement, and administration of DHEA produces a number of beneficial effects in the elderly. Many researchers have suggested that DHEA exerts it function after conversion into more biologically active hormones in peripheral target cells. The actions of DHEA in Leydig cells, a major target cell of DHEA biotransformation in males, are not clear. The present study found that DHEA increased cell viability and decreased reactive oxygen species (ROS) and malondialdehyde contents in H2O2-induced Leydig cells. DHEA significantly increased the activities of superoxide dismutase, catalase and peroxidase, and decreased the DNA damage in H2O2-induced Leydig cells. Apoptosis was significant decreased in H2O2-induced Leydig cells after DHEA treatment. DHEA inhibited the loss of mitochondrial membrane potential (ΔΨm) and the upregulation of the caspase-3 protein level induced by H2O2 in Leydig cells. DHEA also reversed the decrease in PI3K and p-Akt protein levels induced by H2O2. These data showed that DHEA could ameliorate H2O2-induced oxidative damage by increasing anti-oxidative enzyme activities, which resulted in reduced ROS content, and decreased apoptosis, mainly by preventing the loss of ΔΨm and inhibiting caspase-3 protein levels via activation of PI3K/Akt signaling pathways. These results increase our understanding of the molecular mechanism of the anti-ageing effect of DHEA.

  8. 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

  9. Fisetin inhibits UVB-induced cutaneous inflammation and activation of PI3K/AKT/NFκB signaling pathways in SKH-1 hairless mice.

    PubMed

    Pal, Harish Chandra; Athar, Mohammad; Elmets, Craig A; Afaq, Farrukh

    2015-01-01

    Solar ultraviolet B (UVB) radiation has been shown to induce inflammation, DNA damage, p53 mutations and alterations in signaling pathways eventually leading to skin cancer. In this study, we investigated whether fisetin reduces inflammatory responses and modulates PI3K/AKT/NFκB cell survival signaling pathways in UVB-exposed SKH-1 hairless mouse skin. Mice were exposed to 180 mJ cm(-2) of UVB radiation on alternate days for a total of seven exposures, and fisetin (250 and 500 nmol) was applied topically after 15 min of each UVB exposure. Fisetin treatment to UVB-exposed mice resulted in decreased hyperplasia and reduced infiltration of inflammatory cells. Fisetin treatment also reduced inflammatory mediators such as COX-2, PGE2 as well as its receptors (EP1-EP4) and MPO activity. Furthermore, fisetin reduced the level of inflammatory cytokines TNFα, IL-1β and IL-6 in UVB-exposed skin. Fisetin treatment also reduced cell proliferation markers as well as DNA damage as evidenced by increased expression of p53 and p21 proteins. Further studies revealed that fisetin inhibited UVB-induced expression of PI3K, phosphorylation of AKT and activation of the NFκB signaling pathway in mouse skin. Overall, these data suggest that fisetin may be useful against UVB-induced cutaneous inflammation and DNA damage.

  10. Co-targeting the PI3K/mTOR and JAK2 signalling pathways produces synergistic activity against myeloproliferative neoplasms

    PubMed Central

    Bartalucci, Niccolò; Tozzi, Lorenzo; Bogani, Costanza; Martinelli, Serena; Rotunno, Giada; Villeval, Jean-Luc; Vannucchi, Alessandro M

    2013-01-01

    Aberrant JAK2 signalling plays a central role in myeloproliferative neoplasms (MPN). JAK2 inhibitors have proven to be clinically efficacious, however, they are not mutation-specific and competent enough to suppress neoplastic clonal haematopoiesis. We hypothesized that, by simultaneously targeting multiple activated signalling pathways, MPN could be more effectively treated. To this end we investigated the efficacy of BEZ235, a dual PI3K/mTOR inhibitor, alone and in combination with the JAK1/JAK2 inhibitor ruxolitinib, in different preclinical models of MPN. Single-agent BEZ235 inhibited the proliferation and induced cell cycle arrest and apoptosis of mouse and human JAK2V617F mutated cell lines at concentrations significantly lower than those required to inhibit the wild-type counterpart, and preferentially prevented colony formation from JAK2V617F knock-in mice and patients' progenitor cells compared with normal ones. Co-treatment of BEZ235 and ruxolitinib produced significant synergism in all these in-vitro models. Co-treatment was also more effective than single drugs in reducing the extent of disease and prolonging survival of immunodeficient mice injected with JAK2V617F-mutated Ba/F3-EPOR cells and in reducing spleen size, decreasing reticulocyte count and improving spleen histopathology in conditional JAK2V617F knock-in mice. In conclusion, combined inhibition of PI3K/mTOR and JAK2 signalling may represent a novel therapeutic strategy in MPN. PMID:24237791

  11. Insulin-induced Drosophila S6 kinase activation requires phosphoinositide 3-kinase and protein kinase B.

    PubMed Central

    Lizcano, Jose M; Alrubaie, Saif; Kieloch, Agnieszka; Deak, Maria; Leevers, Sally J; Alessi, Dario R

    2003-01-01

    An important mechanism by which insulin regulates cell growth and protein synthesis is through activation of the p70 ribosomal S6 protein kinase (S6K). In mammalian cells, insulin-induced PI3K (phosphoinositide 3-kinase) activation, generates the lipid second messenger PtdIns(3,4,5) P (3), which is thought to play a key role in triggering the activation of S6K. Although the major components of the insulin-signalling pathway are conserved in Drosophila, recent studies suggested that S6K activation does not require PI3K in this system. To investigate further the role of dPI3K (Drosophila PI3K) in dS6K (Drosophila S6K) activation, we examined the effect of two structurally distinct PI3K inhibitors on insulin-induced dS6K activation in Kc167 and S2 Drosophila cell lines. We found that both inhibitors prevented insulin-stimulated phosphorylation and activation of dS6K. To investigate further the role of the dPI3K pathway in regulating dS6K activation, we also used dsRNAi (double-stranded RNA-mediated interference) to decrease expression of dPI3K and the PtdIns(3,4,5) P (3) phosphatase dPTEN ( Drosophila phosphatase and tensin homologue deleted on chromosome 10) in Kc167 and S2 cells. Knock-down of dPI3K prevented dS6K activation, whereas knock-down of dPTEN, which would be expected to increase PtdIns(3,4,5) P (3) levels, stimulated dS6K activity. Moreover, when the expression of the dPI3K target, dPKB (Drosophila protein kinase B), was decreased to undetectable levels, we found that insulin could no longer trigger dS6K activation. This observation provides the first direct demonstration that dPKB is required for insulin-stimulated dS6K activation. We also present evidence that the amino-acid-induced activation of dS6K in the absence of insulin, thought to be mediated by dTOR (Drosophila target of rapamycin), which is unaffected by the inhibition of dPI3K by wortmannin. The results of the present study support the view that, in Drosophila cells, dPI3K and dPKB, as well d

  12. Soyasaponins can blunt inflammation by inhibiting the reactive oxygen species-mediated activation of PI3K/Akt/NF-kB pathway.

    PubMed

    Zha, Longying; Chen, Jiading; Sun, Suxia; Mao, Limei; Chu, Xinwei; Deng, Hong; Cai, Junwei; Li, Xuefeng; Liu, Zhenqi; Cao, Wenhong

    2014-01-01

    We and others have recently shown that soyasaponins abundant in soybeans can decrease inflammation by suppressing the nuclear factor kappa B (NF-kB)-mediated inflammation. However, the exact molecular mechanisms by which soyasaponins inhibit the NF-kB pathway have not been established. In this study in macrophages, soyasaponins (A1, A2 and I) inhibited the lipopolysaccharide (LPS)-induced release of inflammatory marker prostaglandin E2 (PGE2) to a similar extent as the NF-kB inhibitor (BAY117082). Soyasaponins (A1, A2 and I) also suppressed the LPS-induced expression of cyclooxygenase 2 (COX-2), another inflammatory marker, in a dose-dependent manner by inhibiting NF-kB activation. In defining the associated mechanisms, we found that soyasaponins (A1, A2 and I) blunted the LPS-induced IKKα/β phosphorylation, IkB phosphorylation and degradation, and NF-kB p65 phosphorylation and nuclear translocation. In studying the upstream targets of soyasaponins on the NF-kB pathway, we found that soyasaponins (A1, A2 and I) suppressed the LPS-induced activation of PI3K/Akt similarly as the PI3K inhibitor LY294002, which alone blocked the LPS-induced activation of NF-kB. Additionally, soyasaponins (A1, A2 and I) reduced the LPS-induced production of reactive oxygen species (ROS) to the same extent as the anti-oxidant N-acetyl-L-cysteine, which alone inhibited the LPS-induced phosphorylation of Akt, IKKα/β, IkBα, and p65, transactivity of NF-kB, PGE2 production, and malondialdehyde production. Finally, our results show that soyasaponins (A1, A2 and I) elevated SOD activity and the GSH/GSSG ratio. Together, these results show that soyasaponins (A1, A2 and I) can blunt inflammation by inhibiting the ROS-mediated activation of the PI3K/Akt/NF-kB pathway. PMID:25233217

  13. Soyasaponins Can Blunt Inflammation by Inhibiting the Reactive Oxygen Species-Mediated Activation of PI3K/Akt/NF-kB Pathway

    PubMed Central

    Zha, Longying; Chen, Jiading; Sun, Suxia; Mao, Limei; Chu, Xinwei; Deng, Hong; Cai, Junwei; Li, Xuefeng; Liu, Zhenqi; Cao, Wenhong

    2014-01-01

    We and others have recently shown that soyasaponins abundant in soybeans can decrease inflammation by suppressing the nuclear factor kappa B (NF-kB)-mediated inflammation. However, the exact molecular mechanisms by which soyasaponins inhibit the NF-kB pathway have not been established. In this study in macrophages, soyasaponins (A1, A2 and I) inhibited the lipopolysaccharide (LPS)-induced release of inflammatory marker prostaglandin E2 (PGE2) to a similar extent as the NF-kB inhibitor (BAY117082). Soyasaponins (A1, A2 and I) also suppressed the LPS-induced expression of cyclooxygenase 2 (COX-2), another inflammatory marker, in a dose-dependent manner by inhibiting NF-kB activation. In defining the associated mechanisms, we found that soyasaponins (A1, A2 and I) blunted the LPS-induced IKKα/β phosphorylation, IkB phosphorylation and degradation, and NF-kB p65 phosphorylation and nuclear translocation. In studying the upstream targets of soyasaponins on the NF-kB pathway, we found that soyasaponins (A1, A2 and I) suppressed the LPS-induced activation of PI3K/Akt similarly as the PI3K inhibitor LY294002, which alone blocked the LPS-induced activation of NF-kB. Additionally, soyasaponins (A1, A2 and I) reduced the LPS-induced production of reactive oxygen species (ROS) to the same extent as the anti-oxidant N-acetyl-L-cysteine, which alone inhibited the LPS-induced phosphorylation of Akt, IKKα/β, IkBα, and p65, transactivity of NF-kB, PGE2 production, and malondialdehyde production. Finally, our results show that soyasaponins (A1, A2 and I) elevated SOD activity and the GSH/GSSG ratio. Together, these results show that soyasaponins (A1, A2 and I) can blunt inflammation by inhibiting the ROS-mediated activation of the PI3K/Akt/NF-kB pathway. PMID:25233217

  14. Soyasaponins can blunt inflammation by inhibiting the reactive oxygen species-mediated activation of PI3K/Akt/NF-kB pathway.

    PubMed

    Zha, Longying; Chen, Jiading; Sun, Suxia; Mao, Limei; Chu, Xinwei; Deng, Hong; Cai, Junwei; Li, Xuefeng; Liu, Zhenqi; Cao, Wenhong

    2014-01-01

    We and others have recently shown that soyasaponins abundant in soybeans can decrease inflammation by suppressing the nuclear factor kappa B (NF-kB)-mediated inflammation. However, the exact molecular mechanisms by which soyasaponins inhibit the NF-kB pathway have not been established. In this study in macrophages, soyasaponins (A1, A2 and I) inhibited the lipopolysaccharide (LPS)-induced release of inflammatory marker prostaglandin E2 (PGE2) to a similar extent as the NF-kB inhibitor (BAY117082). Soyasaponins (A1, A2 and I) also suppressed the LPS-induced expression of cyclooxygenase 2 (COX-2), another inflammatory marker, in a dose-dependent manner by inhibiting NF-kB activation. In defining the associated mechanisms, we found that soyasaponins (A1, A2 and I) blunted the LPS-induced IKKα/β phosphorylation, IkB phosphorylation and degradation, and NF-kB p65 phosphorylation and nuclear translocation. In studying the upstream targets of soyasaponins on the NF-kB pathway, we found that soyasaponins (A1, A2 and I) suppressed the LPS-induced activation of PI3K/Akt similarly as the PI3K inhibitor LY294002, which alone blocked the LPS-induced activation of NF-kB. Additionally, soyasaponins (A1, A2 and I) reduced the LPS-induced production of reactive oxygen species (ROS) to the same extent as the anti-oxidant N-acetyl-L-cysteine, which alone inhibited the LPS-induced phosphorylation of Akt, IKKα/β, IkBα, and p65, transactivity of NF-kB, PGE2 production, and malondialdehyde production. Finally, our results show that soyasaponins (A1, A2 and I) elevated SOD activity and the GSH/GSSG ratio. Together, these results show that soyasaponins (A1, A2 and I) can blunt inflammation by inhibiting the ROS-mediated activation of the PI3K/Akt/NF-kB pathway.

  15. Involvement of HDAC1 and the PI3K/PKC signaling pathways in NF-{kappa}B activation by the HDAC inhibitor apicidin

    SciTech Connect

    Kim, Yong Kee . E-mail: yksnbk@kwandong.ac.kr; Seo, Dong-Wan; Kang, Dong-Won; Lee, Hoi Young; Han, Jeung-Whan; Kim, Su-Nam . E-mail: snkim@kist.re.kr

    2006-09-08

    Histone deacetylase (HDAC) inhibitors are appreciated as one of promising anticancer drugs, but they exert differential responses depending on the cell type. We recently reported the critical role of NF-{kappa}B as a modulator in determining cell fate for apoptosis in response to an HDAC inhibitor. In this study, we investigate a possible signaling pathway required for NF-{kappa}B activation in response to the HDAC inhibitor apicidin. Treatment of HeLa cells with apicidin leads to an increase in transcriptional activity of NF-{kappa}B and the expression of its target genes, IL-8 and TNF-{alpha}. TNF-{alpha} expression by apicidin is induced at earlier time points than NF-{kappa}B activation or IL-8 expression. In addition, our data show that the early expression of TNF-{alpha} does not lead to activation of NF-{kappa}B, because disruption of TNF-{alpha} activity by a neutralizing antibody does not affect nuclear translocation of NF-{kappa}B, I{kappa}B{alpha} degradation or reporter gene activation by apicidin. However, this activation of NF-{kappa}B requires the PI3K and PKC signaling pathways, but not ERK or JNK. Furthermore, apicidin activation of NF-{kappa}B seems to result from HDAC1 inhibition, as evidenced by the observation that overexpression of HDAC1, but not HDAC2, 3 or 4, dramatically inhibits NF-{kappa}B reporter gene activity. Collectively, our results suggest that activation of NF-{kappa}B signaling by apicidin requires both the PI3K/PKC signaling pathways and HDAC1, and functions as a critical modulator in determining the cellular effect of apicidin.

  16. Anti-proliferative effect of RCE-4 from Reineckia carnea on human cervical cancer HeLa cells by inhibiting the PI3K/Akt/mTOR signaling pathway and NF-κB activation.

    PubMed

    Bai, Caihong; Yang, Xiaojiao; Zou, Kun; He, Haibo; Wang, Junzhi; Qin, Huilin; Yu, Xiaoqin; Liu, Chengxiong; Zheng, Juyan; Cheng, Fan; Chen, Jianfeng

    2016-06-01

    Cervical cancer is the second leading cause of cancer deaths in women worldwide. In recent years, the studies find that inflammation is a critical component of tumor progression, and the ideal therapeutic methods should be aimed at the inflammation reaction triggers. (1β,3β,5β,25S)-spirostan-1,3-diol1-[α-L-rhamnopyranosyl-(1 → 2)-β-D-xylopyranoside] (RCE-4) was the main active composition of Reineckia carnea (Andr.) Kunth. It significantly induced apoptosis in cervical cancer Caski cells through the mitochondrial pathway in our previous studies; however, its underlying mechanism remains poorly understood. This study aimed to further evaluate the effect of RCE-4 on human cervical cancer HeLa cells. Based on this observation, we investigated the anti-cervical cancer effect of RCE-4 by modulating phosphatidylinositol 3-kinase/protein kinase-B/mammalian target of rapamycin (PI3K/Akt/mTOR) signaling pathway, nuclear factor-kappa B (NF-κB) activation, and inflammation-related key factors in HeLa cells. The results indicated that the HeLa cell was the most sensitive with an IC50 of 7.01 μM; RCE-4 significantly promoted the release of cellular lactate dehydrogenase (LDH); increased DNA fragmentation and apoptosis; reduced PI3K, Akt, mTOR, and NF-κBp65 phosphorylation levels; increased the Bax and cleaved poly (ADP-ribose) polymerase (PARP) protein levels; suppressed Bcl-2 protein expression; elevated the Bax/Bcl-2 expression ratio; and decreased the interleukin-1 beta (IL-1β) and interleukin-6 (IL-6) mRNA expressions in HeLa cells in a concentration-dependent manner. These findings suggest that RCE-4 exerted beneficially anti-cervical cancer effect on HeLa cells, mainly inhibiting PI3K/Akt/mTOR signaling pathway phosphorylation and NF-κB activation, promoting HeLa cell apoptosis. Graphical abstract Anti-tumor effect of RCE-4 on HeLa cells.

  17. 14-3-3ζ up-regulates hypoxia-inducible factor-1α in hepatocellular carcinoma via activation of PI3K/Akt/NF-кB signal transduction pathway

    PubMed Central

    Tang, Yufu; Lv, Pengfei; Sun, Zhongyi; Han, Lei; Luo, Bichao; Zhou, Wenping

    2015-01-01

    14-3-3ζ protein, a member of 14-3-3 family, plays important roles in multiple cellular processes. Our previous study showed that 14-3-3ζ could bind to regulate the expression of hypoxia-inducible factor-1α (HIF-1α), which is induced by hypoxia and a crucial factor for induction of tumor metastasis. Moreover, we also have confirmed the response of 14-3-3ζ to hypoxia in our unpublished data as well. Thus, in the present study, we attempted to reveal that whether the regulation effect of 14-3-3ζ on HIF-1α functioned in a similar pattern as hypoxia. Stable regulation of 14-3-3ζ in human HCC cell line SMMC-772 and HCC-LM3 was achieved. The regulation of 14-3-3ζ on HIF-1α mRNA transcription was evaluated by luciferase activity assay and quantitative real-time PCR (qPCR). The effect of 14-3-3ζ on the production of HIF-1α and pathways determining HIF-1α’s response to hypoxia was assessed using western blotting assay. Our results showed that regulation of 14-3-3ζ expression influenced the activity of HIF-1α, phosphatidyl inositol 3-kinase (PI3K), Akt, extracellular signal-regulated kinase 1/2 (ERK1/2), and nuclear factor kappa B (NF-кB). Blocking of these pathways using indicated inhibitors revealed that 14-3-3ζ enhanced the production of HIF-1α via the activation of PI3K/Akt/NF-кB pathway, which was identical to hypoxia induced HIF-1α expression. For the first time, our study described the key role of 14-3-3ζ in the HIF-1α production in HCC cells. And the molecule exerted its function on HIF-1α both by directly binding to it and via PI3K/Akt/NF-кB signal transduction pathway. PMID:26884855

  18. Bis(propyl)-cognitin Prevents β-amyloid-induced Memory Deficits as Well as Synaptic Formation and Plasticity Impairments via the Activation of PI3-K Pathway.

    PubMed

    Jiang, Liting; Huang, Meng; Xu, Shujun; Wang, Yu; An, Pengyuan; Feng, Chenxi; Chen, Xiaowei; Wei, Xiaofei; Han, Yifan; Wang, Qinwen

    2016-08-01

    Bis(propyl)-cognitin (B3C), derived from tacrine linked with three methylene (-CH2-) groups, is a dimerized molecule interacting multiple targets. During the past several years, it has been reported as a promising therapeutic drug for Alzheimer's disease (AD) and other neurodegenerative disorders. However, the therapeutic mechanism of B3C for AD needs further demonstration. Based on a combination of behavioral tests, electrophysiological technique, immunocytochemistry, and live cell imaging, we studied the effects and the underlying mechanism of B3C on the impairments of cognitive function, synapse formation, and synaptic plasticity induced by soluble amyloid-β protein (Aβ) oligomers. Our study showed that spatial learning and memory in a Morris water maze task and recognition memory in a novel object recognition task were significantly decreased in the AD model mice created by hippocampal injection of Aβ. Chronic administration of B3C for 21 days prevented the memory impairments of the AD model mice in a dose-dependent manner. Live cell imaging study showed that 2-h pretreatment of B3C prevented the decrease in the number of filopodia and synapses induced by Aβ (0.5 μM) in a dose-dependent manner. Besides, electrophysiological recording data showed that the inhibition of long-term potentiation (LTP) induced by Aβ1-42 oligomers in the dentate gyrus (DG) of hippocampus was prevented by B3C in a dose-dependent manner. Furthermore, we found that the neuroprotective effect of B3C against Aβ-oligomer-induced impairments of synaptic formation and plasticity could be partially blocked by a specific phosphatidylinositol 3-kinase (PI3-K) inhibitor LY294002 (50 μM). Therefore, these results indicate that B3C can prevent Aβ-oligomer-induced cognitive deficits, synaptic formation impairments, and synaptic plasticity impairments in a concentration-dependent manner. These effects of B3C are partially mediated via the PI3-K pathway. This study provides novel insights

  19. Activation of RAF/MEK/ERK and PI3K/AKT/mTOR pathways in pituitary adenomas and their effects on downstream effectors.

    PubMed

    Dworakowska, D; Wlodek, E; Leontiou, C A; Igreja, S; Cakir, M; Teng, M; Prodromou, N; Góth, M I; Grozinsky-Glasberg, S; Gueorguiev, M; Kola, B; Korbonits, M; Grossman, A B

    2009-12-01

    Raf/MEK/ERK and phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) cascades are key signalling pathways interacting with each other to regulate cell growth and tumourigenesis. We have previously shown B-Raf and Akt overexpression and/or overactivation in pituitary adenomas. The aim of this study is to assess the expression of their downstream components (MEK1/2, ERK1/2, mTOR, TSC2, p70S6K) and effectors (c-MYC and CYCLIN D1). We studied tissue from 16 non-functioning pituitary adenomas (NFPAs), six GH-omas, six prolactinomas and six ACTH-omas, all collected at transsphenoidal surgery; 16 normal autopsy pituitaries were used as controls. The expression of phospho and total protein was assessed with western immunoblotting, and the mRNA expression with quantitative RT-PCR. The expression of pSer217/221 MEK1/2 and pThr183 ERK1/2 (but not total MEK1/2 or ERK1/2) was significantly higher in all tumour subtypes in comparison to normal pituitaries. There was no difference in the expression of phosphorylated/total mTOR, TSC2 or p70S6K between pituitary adenomas and controls. Neither c-MYC phosphorylation at Ser 62 nor total c-MYC was changed in the tumours. However, c-MYC phosphorylation at Thr58/Ser62 (a response target for Akt) was decreased in all tumour types. CYCLIN D1 expression was higher only in NFPAs. The mRNA expression of MEK1, MEK2, ERK1, ERK2, c-MYC and CCND1 was similar in all groups. Our data indicate that in pituitary adenomas both the Raf/MEK/ERK and PI3K/Akt/mTOR pathways are upregulated in their initial cascade, implicating a pro-proliferative signal derangement upstream to their point of convergence. However, we speculate that other processes, such as senescence, attenuate the changes downstream in these benign tumours. PMID:19620247

  20. 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

  1. 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.

  2. Synthesis and antitumor activity evaluation of PI3K inhibitors containing 3-substituted quinazolin-4(3H)-one moiety.

    PubMed

    Zhang, Hao; Xin, Min-Hang; Xie, Xiao-Xiao; Mao, Shuai; Zuo, Sai-Jie; Lu, She-Min; Zhang, San-Qi

    2015-12-15

    In present study, a series of N-(2-methoxy-5-(3-substituted quinazolin-4(3H)-one-6-yl)-pyridin-3-yl)phenylsulfonamide were synthesized. Their antiproliferative activities in vitro were evaluated via MTT assay against HCT116 and MCF-7 cancer cell lines. The SAR of title compounds was discussed. The compounds (S)-C5 and (S)-C8 displayed potent inhibitory activity against PI3Ks and mTOR, especially against PI3Kα. In addition, compound (S)-C5 can efficaciously inhibit tumor growth in a mice S-180 model. These findings suggest that our designed compounds can serve as potent PI3K inhibitors and effective anticancer agents. PMID:26652969

  3. PIK3CAH1047R and Her2 initiated mammary tumors escape PI3K dependency by compensatory activation of MEK-ERK signaling

    PubMed Central

    Cheng, Hailing; Liu, Pixu; Ohlson, Carolynn; Xu, Erbo; Symonds, Lynn; Isabella, Adam; Muller, William J.; Lin, Nancy U.; Krop, Ian E.; Roberts, Thomas M.; Winer, Eric P.; Arteaga, Carlos L.; Zhao, Jean J.

    2015-01-01

    Human breast cancers that have HER2 amplification/overexpression frequently carry PIK3CA mutations, and are often associated with a worse prognosis. However, the role of PIK3CA mutations in the initiation and maintenance of these breast cancers remains elusive. In the present study, we generated a compound mouse model that genetically mimics HER2 positive breast cancer with coexisting PIK3CAH1047R. Induction of PIK3CAH1047R expression in mouse mammary glands with constitutive expression of activated Her2/Neu resulted in accelerated mammary tumorigenesis with enhanced metastatic potential. Interestingly, inducible expression of mutant PIK3CA resulted in a robust activation of PI3K/AKT signaling but attenuation of Her2/Her3 signaling, and this can be reversed by deinduction of PIK3CAH1047R expression. Strikingly, while these Her2+ PIK3CAH1047R initiated primary mammary tumors are refractory to HER2-targeted therapy, all tumors responded to inactivation of the oncogenic PIK3CAH1047R, a situation closely mimicking the use of a highly effective inhibitor specifically targeting the mutant PIK3CA/p110a. Notably, these tumors eventually resumed growth, and a fraction of them escaped PI3K dependence by compensatory ERK activation, which can be blocked by combined inhibition of Her2 and MEK. Together, these results suggest that PIK3CA-specific inhibition as a monotherapy followed by combination therapy targeting MAPK and HER2 in a timely manner may be an effective treatment approach against HER2 positive cancers with coexisting PIK3CA-activating mutations. PMID:26640141

  4. 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

  5. TLR9 activation induces normal neutrophil responses in a child with IRAK-4 deficiency: involvement of the direct PI3K pathway.

    PubMed

    Hoarau, Cyrille; Gérard, Bénédicte; Lescanne, Emmanuel; Henry, Dominique; François, Stéphanie; Lacapère, Jean-Jacques; El Benna, Jamel; Dang, Pham My-Chan; Grandchamp, Bernard; Lebranchu, Yvon; Gougerot-Pocidalo, Marie-Anne; Elbim, Carole

    2007-10-01

    Polymorphonuclear neutrophils (PMN) play a key role in innate immunity. Their activation and survival are tightly regulated by microbial products via pattern recognition receptors such as TLRs, which mediate recruitment of the IL-1R-associated kinase (IRAK) complex. We describe a new inherited IRAK-4 deficiency in a child with recurrent pyogenic bacterial infections. Analysis of the IRAK4 gene showed compound heterozygosity with two mutations: a missense mutation in the death domain of the protein (pArg12Cys) associated in cis-with a predicted benign variant (pArg391His); and a splice site mutation in intron 7 that led to the skipping of exon 7. A nontruncated IRAK-4 protein was detected by Western blotting. The patient's functional deficiency of IRAK-4 protein was confirmed by the absence of IRAK-1 phosphorylation after stimulation with all TLR agonists tested. The patient's PMNs showed strongly impaired responses (L-selectin and CD11b expression, oxidative burst, cytokine production, cell survival) to TLR agonists which engage TLR1/2, TLR2/6, TLR4, and TLR7/8; in contrast, the patient's PMN responses to CpG-DNA (TLR9) were normal, except for cytokine production. The surprisingly normal effect of CpG-DNA on PMN functions and apoptosis disappeared after pretreatment with PI3K inhibitors. Together, these results suggest the existence of an IRAK-4-independent TLR9-induced transduction pathway leading to PI3K activation. This alternative pathway may play a key role in PMN control of infections by microorganisms other than pyogenic bacteria in inherited IRAK-4 deficiency.

  6. Evaluation of In Vitro Activity of the Class I PI3K Inhibitor Buparlisib (BKM120) in Pediatric Bone and Soft Tissue Sarcomas

    PubMed Central

    Anderson, Jennifer L.; Park, Ann; Akiyama, Ryan; Tap, William D.; Denny, Christopher T.; Federman, Noah

    2015-01-01

    Pediatric bone and soft tissue sarcomas often display increased Akt phosphorylation through up regulation of insulin-like growth factor (IGF1) signaling. Additionally, Akt signaling has been linked to resistance to IGF1 receptor (IGF1R) and mTOR (mammalian target of rapamycin) inhibitors in sarcoma, further demonstrating the role of Akt in tumor survival. This suggests targeting components of the PI3K/Akt pathway may be an effective therapeutic strategy. Here, we investigated the in vitro activity of the pan-class I PI3K inhibitor buparlisib (BKM120) in pediatric bone and soft tissue sarcomas. Buparlisib inhibited activation of Akt and signaling molecules downstream of mTORC1 (mTOR complex 1) in Ewing sarcoma, osteosarcoma, and rhabdomyosarcoma cell lines. Anti-proliferative effects were observed in both anchorage dependent and independent conditions and apoptosis was induced within 24 hours of drug treatment. Buparlisib demonstrated cytotoxicity as a single agent, but was found to be more effective when used in combination. Synergy was observed when buparlisib was combined with the IGF1R inhibitor NVP-AEW541 and the mTORC1 inhibitor rapamycin. The addition of NVP-AEW541 also further reduced phospho-Akt levels and more potently induced apoptosis compared to buparlisib treatment alone. Additionally, the combination of buparlisib with the MEK1/2 inhibitor trametinib resulted in synergy in sarcoma cell lines possessing MAPK pathway mutations. Taken together, these data indicate buparlisib could be a novel therapy for the treatment of pediatric bone and soft tissue sarcomas. PMID:26402468

  7. Evaluation of In Vitro Activity of the Class I PI3K Inhibitor Buparlisib (BKM120) in Pediatric Bone and Soft Tissue Sarcomas.

    PubMed

    Anderson, Jennifer L; Park, Ann; Akiyama, Ryan; Tap, William D; Denny, Christopher T; Federman, Noah

    2015-01-01

    Pediatric bone and soft tissue sarcomas often display increased Akt phosphorylation through up regulation of insulin-like growth factor (IGF1) signaling. Additionally, Akt signaling has been linked to resistance to IGF1 receptor (IGF1R) and mTOR (mammalian target of rapamycin) inhibitors in sarcoma, further demonstrating the role of Akt in tumor survival. This suggests targeting components of the PI3K/Akt pathway may be an effective therapeutic strategy. Here, we investigated the in vitro activity of the pan-class I PI3K inhibitor buparlisib (BKM120) in pediatric bone and soft tissue sarcomas. Buparlisib inhibited activation of Akt and signaling molecules downstream of mTORC1 (mTOR complex 1) in Ewing sarcoma, osteosarcoma, and rhabdomyosarcoma cell lines. Anti-proliferative effects were observed in both anchorage dependent and independent conditions and apoptosis was induced within 24 hours of drug treatment. Buparlisib demonstrated cytotoxicity as a single agent, but was found to be more effective when used in combination. Synergy was observed when buparlisib was combined with the IGF1R inhibitor NVP-AEW541 and the mTORC1 inhibitor rapamycin. The addition of NVP-AEW541 also further reduced phospho-Akt levels and more potently induced apoptosis compared to buparlisib treatment alone. Additionally, the combination of buparlisib with the MEK1/2 inhibitor trametinib resulted in synergy in sarcoma cell lines possessing MAPK pathway mutations. Taken together, these data indicate buparlisib could be a novel therapy for the treatment of pediatric bone and soft tissue sarcomas.

  8. 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

  9. Calcium Signaling Involvement in Cadmium-Induced Astrocyte Cytotoxicity and Cell Death Through Activation of MAPK and PI3K/Akt Signaling Pathways.

    PubMed

    Jiang, Jiao Hua; Ge, Guo; Gao, Kai; Pang, Ying; Chai, Rui Chao; Jia, Xi Hua; Kong, Jin Ge; Yu, Albert Cheung-Hoi

    2015-09-01

    Cadmium (Cd), a highly ubiquitous toxic heavy metal, can contaminate the environment, including agricultural soil, water and air, via industrial runoff and other sources of pollution. Cd accumulated in the body via direct exposure or through the food chain results in neurodegeneration and many other diseases. Previous studies on its toxicity in the central nervous system (CNS) focused mainly on neurons. To obtain a more comprehensive understanding of Cd toxicity for the CNS, we investigated how astrocytes respond to acute and chronic Cd exposure and its toxic molecular mechanisms. When primary cultures of cerebral cortical astrocytes incubated with 1-300 μM CdCl2, morphological changes, LDH release and cell death were observed in a time and dose-dependent manner. Further studies demonstrated that acute and chronic Cd treatment phosphorylated JNK, p38 and Akt to different degrees, while ERK1/2 was only phosphorylated under low doses of Cd (10 μM) exposure. Inhibition of JNK and PI3K/Akt, but not of p38, could partially protect astrocyte from cytotoxicity in chronic and acute Cd exposure. Moreover, Cd also induced a strong calcium signal, while BAPTA, a specific intracellular calcium (Ca(2+)) chelator, prevented Cd-induced intracellular increase of calcium levels in astrocytes; inhibited the Cd-induced activation of ERK1/2, JNK, p38 and Akt; and also significantly reduced astrocyte cell death. All of these results suggested that the Cd-Ca(2+)-MAPK and PI3K/Akt signaling pathways were involved in Cd-induced toxicity in astrocytes. This toxicity involvement indicates that these pathways may be exploited as a target for the prevention of Cd-induced neurodegenerative diseases. PMID:26248512

  10. NTRK2 activation cooperates with PTEN deficiency in T-ALL through activation of both the PI3K-AKT and JAK-STAT3 pathways.

    PubMed

    Yuzugullu, Haluk; Von, Thanh; Thorpe, Lauren M; Walker, Sarah R; Roberts, Thomas M; Frank, David A; Zhao, Jean J

    2016-01-01

    Loss of PTEN, a negative regulator of the phosphoinositide 3-kinase signaling pathway, is a frequent event in T-cell acute lymphoblastic leukemia, suggesting the importance of phosphoinositide 3-kinase activity in this disease. Indeed, hyperactivation of the phosphoinositide 3-kinase pathway is associated with the disease aggressiveness, poor prognosis and resistance to current therapies. To identify a molecular pathway capable of cooperating with PTEN deficiency to drive oncogenic transformation of leukocytes, we performed an unbiased transformation screen with a library of tyrosine kinases. We found that activation of NTRK2 is able to confer a full growth phenotype of Ba/F3 cells in an IL3-independent manner in the PTEN-null setting. NTRK2 activation cooperates with PTEN deficiency through engaging both phosphoinositide3-kinase/AKT and JAK/STAT3 pathway activation in leukocytes. Notably, pharmacological inhibition demonstrated that p110α and p110δ are the major isoforms mediating the phosphoinositide 3-kinase/AKT signaling driven by NTRK2 activation in PTEN-deficient leukemia cells. Furthermore, combined inhibition of phosphoinositide 3-kinase and STAT3 significantly suppressed proliferation of PTEN-mutant T-cell acute lymphoblastic leukemia both in culture and in mouse xenografts. Together, our data suggest that a unique conjunction of PTEN deficiency and NTRK2 activation in T-cell acute lymphoblastic leukemia, and combined pharmacologic inhibition of phosphoinositide 3-kinase and STAT3 signaling may serve as an effective and durable therapeutic strategy for T-cell acute lymphoblastic leukemia. PMID:27672444

  11. 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.

  12. 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

  13. 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

  14. 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.

  15. 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.

  16. 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

  17. 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

  18. Epigallocatechin gallate-induced modulation of FoxO signaling in mammalian cells and C. elegans: FoxO stimulation is masked via PI3K/Akt activation by hydrogen peroxide formed in cell culture.

    PubMed

    Bartholome, André; Kampkötter, Andreas; Tanner, Stephan; Sies, Helmut; Klotz, Lars-Oliver

    2010-09-01

    The green tea flavonoid epigallocatechin gallate (EGCG) is demonstrated in this study to modulate FoxO transcription factors in human skin fibroblasts in culture. EGCG at 1 microM stimulated FoxO transcription factor nuclear accumulation and DNA binding activity. This effect was masked at higher EGCG concentrations (100 microM) by EGCG-derived hydrogen peroxide generated in cell culture media that stimulates phosphoinositide-3'-kinase (PI3K)/Akt signaling to attenuate FoxO activity, involving FoxO phosphorylation, nuclear exclusion and attenuation of DNA binding activity. Like low concentrations of EGCG, harmine, an inhibitor of the FoxO kinase DYRK1a, stimulated FoxO nuclear accumulation and DNA binding activity. Exposure of Caenorhabditis elegans worms to EGCG caused nuclear accumulation of the FoxO ortholog, DAF-16, and enhanced expression of the DAF-16 target gene, sod-3. In line with the role of FoxO/DAF-16 in the control of life span, C. elegans mean and maximum life span were enhanced by 20% and 13%, respectively, by EGCG. PMID:20513639

  19. Pyrroloquinoline quinone inhibits oxygen/glucose deprivation-induced apoptosis by activating the PI3K/AKT pathway in cardiomyocytes.

    PubMed

    Xu, Feng; Yu, Haixia; Liu, Jinyao; Cheng, Lu

    2014-01-01

    The purposes of this study were to examine the protective effect of pyrroloquinoline quinone (PQQ) on oxygen/glucose deprivation (OGD)-induced injury to H9C2 rat cardiomyocytes and to investigate the mechanism. Using H9C2 cells cultured in vitro, we examined changes in cell viability with an MTT assay at 12, 24, and 48 h after injury induced by OGD. Various concentrations of PQQ (1, 10, and 100 μM) were added, and the effect of PQQ on cell viability after OGD was assessed using the MTT assay. Thus, the optimal concentration of PQQ for the protection of cardiomyocytes against oxygen and glucose deprivation injury was determined. We also used flow cytometry analysis to examine the effect of PQQ on H9C2 cells with OGD-induced injury. The molecular probe 2',7'-dichlorofluorescin diacetate was used to label the H9C2 cells, and flow cytometry was used to detect the effect of PQQ on reactive oxygen species (ROS) content. After labeling the H9C2 cells using a mitochondrial green fluorescent probe (Mito-Tracker Green), we measured the change in the mitochondrial content of PQQ-treated H9C2 cells. Western blotting was used to examine the effect of PQQ on the phosphatidylinositol 3-kinase (PI3K)/Akt pathway in the H9C2 cells. The results of the MTT assay showed that 48 h of OGD significantly injured the H9C2 cells (p < 0.01) and that treatment with 100 μM PQQ effectively decreased the level of OGD-induced injury (p < 0.01). The results of the flow cytometry analysis showed that PQQ significantly reduced apoptosis in H9C2 cells subjected to OGD (p < 0.05). In addition, OGD significantly increased the ROS level in H9C2 cells (p < 0.01), and PQQ significantly inhibited this increase (p < 0.05). The results of the Mito-Tracker Green staining suggested that PQQ effectively inhibited the decrease in mitochondrial content caused by OGD (p < 0.05). Western blot analysis showed that PQQ partially reversed the decrease in Akt phosphorylation that was caused by OGD (p

  20. scAAV9-VEGF prolongs the survival of transgenic ALS mice by promoting activation of M2 microglia and the PI3K/Akt pathway.

    PubMed

    Wang, Ying; Duan, Weisong; Wang, Wan; Di Wen; Liu, Yaling; Liu, Yakun; Li, Zhongyao; Hu, Haojie; Lin, Huiqian; Cui, Can; Li, Dongxiao; Dong, Hui; Li, Chunyan

    2016-10-01

    Amyotrophic lateral sclerosis (ALS) is an adult-onset neurodegenerative disease that leads to paralysis and death three to five years after diagnosis in most patients. The disease is incurable, and the mechanism of motoneuron degeneration remains unknown, although research has demonstrated that activated microglia are involved in motor neuron death. Here, we used a simple method to deliver AAV9 virus by direct intrathecal injection and found that scAAV9-VEGF-165 improved the motor performance and prolonged the life span of SOD1-G93A mice. Furthermore, scAAV9-VEGF-165 activated the PI3K/Akt survival pathway and increased the level of Bcl-2, which contributed to the protection of motor neurons. Additionally, scAAV9-VEGF-165 attenuated the expression of classically activated (M1) microglial markers and enhanced the expression of alternatively activated (M2) microglial markers. Taken together, the results of our study suggest that simple, direct intrathecal injection of scAAV9-VEGF-165 may have a curative effect for ALS. PMID:27392886

  1. Suppressive effect of exogenous carbon monoxide on endotoxin-stimulated platelet over-activation via the glycoprotein-mediated PI3K-Akt-GSK3β pathway

    PubMed Central

    Liu, Dadong; Wang, Xu; Qin, Weiting; Chen, Jingjia; Wang, Yawei; Zhuang, Mingfeng; Sun, Bingwei

    2016-01-01

    Platelet activation is an important event involved in the pathophysiological processes of the coagulation system. Clinical evidence has shown that platelets undergo distinctive pathological processes during sepsis. Unfortunately, how platelets physiologically respond to inflammation or sepsis is not well understood. In this study, we used a lipopolysaccharide (LPS)-stimulated platelet model to systemically investigate alterations in membrane glycoprotein expression, molecular signaling, morphology and critical functions of platelets. We found that platelet adhesion, aggregation, secretion, and spreading on immobilized fibrinogen and the expression of platelet membrane glycoproteins were significantly increased by LPS stimulation, and these changes were accompanied by a significant decrease in cGMP levels and an abnormal distribution of platelet α-granules. Exogenous CO reversed these alterations. Profound morphological changes in LPS-stimulated platelets were observed using atomic force microscopy and phase microscopy. Furthermore, the elevated activities of PI3Ks, AKt and GSK-3β were effectively suppressed by exogenous CO, leading to the improvement of platelet function. Together, these results provide evidence that platelet over-activation persists under LPS-stimulation and that exogenous CO plays an important role in suppressing platelet activation via the glycoprotein-mediated PI3K-Akt-GSK3β pathway. PMID:27020460

  2. Glycoprotein nonmetastatic melanoma protein B extracellular fragment shows neuroprotective effects and activates the PI3K/Akt and MEK/ERK pathways via the Na+/K+-ATPase

    PubMed Central

    Ono, Yoko; Tsuruma, Kazuhiro; Takata, Masafumi; Shimazawa, Masamitsu; Hara, Hideaki

    2016-01-01

    Glycoprotein nonmetastatic melanoma protein B (GPNMB) plays important roles in various types of cancer and amyotrophic lateral sclerosis (ALS). The details of GPNMB function and its interacting protein have not been clarified. Therefore, to identify GPNMB binding partners on the cell membrane, we used membrane protein library/BLOTCHIP-MS technology, which enables us to analyze all cell membrane proteins as binding partners of the GPNMB extracellular fragment. As a result of a comprehensive search, we identified the alpha subunits of Na+/K+-ATPase (NKA) as a possible binding partner. We confirmed the interaction between the GPNMB extracellular fragment and NKA by immunoprecipitation and immunostaining in NSC-34 cells. Indeed, endogenous GPNMB extracellular fragment bound to and colocalized with NKA alpha subunits. Furthermore, exogenous GPNMB extracellular fragment, i.e., human recombinant GPNMB, also bound to and colocalized with NKA alpha subunits. Additionally, we found that the GPNMB extracellular fragment had neuroprotective effects and activated the phosphoinositide 3-kinase (PI3K)/Akt and mitogen-activated protein kinase (MAPK)-extracellular signal-regulated kinase (ERK) kinase (MEK)/ERK pathways via NKA. These findings indicated that NKA may act as a novel “receptor” for the GPNMB extracellular fragment, offering additional molecular targets for the treatment of GPNMB-related diseases, including various types of cancer and ALS. PMID:26988030

  3. 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.

  4. Paeoniflorin ameliorates ANIT-induced cholestasis by activating Nrf2 through an PI3K/Akt-dependent pathway in rats.

    PubMed

    Chen, Zhe; Ma, Xiao; Zhu, Yun; Zhao, Yanling; Wang, Jiabo; Li, Ruisheng; Chen, Chang; Wei, Shizhang; Jiao, Wenjuan; Zhang, Yaming; Li, Jianyu; Wang, Lifu; Wang, Ruilin; Liu, Honghong; Shen, Honghui; Xiao, Xiaohe

    2015-11-01

    Cholestasis causes hepatic accumulation of bile acids leading to liver injury, fibrosis and liver failure. Paeoniflorin, the major active compound isolated from the roots of Paeonia lactiflora pall and Paeonia veitchii Lynch, is extensively used for liver diseases treatment in China. However, the mechanism of paeoniflorin's hepatoprotective effect on cholestasis has not been investigated yet. In this study, we administered paeoniflorin to rats for 3 days prior to alpha-naphthylisothiocyanate (ANIT) administration for once, then went on administering paeoniflorin to rats for 3 days. The data demonstrated that paeoniflorin significantly prevented ANIT-induced change in serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphates (ALP), serum total bilirubin (TBIL), direct bilirubin (DBIL), total bile acid (TBA) and gamma-glutamyl transpeptidase (γ-GT). Histology examination revealed that paeoniflorin treatment rats relieved more liver injury and bile duct proliferation than ANIT-administered rats. Moreover, our data indicated that paeoniflorin could restore glutathione (GSH) and its related synthase glutamate-cysteine ligase catalytic subunit (GCLc) and glutamate-cysteine ligase modifier subunit (GCLm) in ANIT-treated group. In addition, the RNA and protein expression of Akt and nuclear factor-E2-related factor-2 (Nrf2) were also activated by paeoniflorin in ANIT-induced rats. These findings indicated that paeoniflorin protected ANIT-induced cholestasis and increased GSH synthesis by activating Nrf2 through PI3K/Akt-dependent pathway. Therefore, paeoniflorin might be a potential therapeutic agent for cholestasis. PMID:26269092

  5. mTOR Activation by PI3K/Akt and ERK Signaling in Short ELF-EMF Exposed Human Keratinocytes

    PubMed Central

    Patruno, Antonia; Pesce, Mirko; Grilli, Alfredo; Speranza, Lorenza; Franceschelli, Sara; De Lutiis, Maria Anna; Vianale, Giovina; Costantini, Erica; Amerio, Paolo; Muraro, Raffaella; Felaco, Mario; Reale, Marcella

    2015-01-01

    Several reports suggest that ELF-EMF exposures interact with biological processes including promotion of cell proliferation. However, the molecular mechanisms by which ELF-EMF controls cell growth are not completely understood. The present study aimed to investigate the effect of ELF-EMF on keratinocytes proliferation and molecular mechanisms involved. Effect of ELF-EMF (50 Hz, 1 mT) on HaCaT cell cycle and cells growth and viability was monitored by FACS analysis and BrdU assay. Gene expression profile by microarray and qRT-PCR validation was performed in HaCaT cells exposed or not to ELF-EMF. mTOR, Akt and MAPKs expressions were evaluated by Western blot analysis. In HaCaT cells, short ELF-EMF exposure modulates distinct patterns of gene expression involved in cell proliferation and in the cell cycle. mTOR activation resulted the main molecular target of ELF-EMF on HaCaT cells. Our data showed the increase of the canonical pathway of mTOR regulation (PI3K/Akt) and activation of ERK signaling pathways. Our results indicate that ELF-EMF selectively modulated the expression of multiple genes related to pivotal biological processes and functions that play a key role in physio-pathological mechanisms such as wound healing. PMID:26431550

  6. EGFR Activation Leads to Cell Death Independent of PI3K/AKT/mTOR in an AD293 Cell Line

    PubMed Central

    Popeda, Marta; Ksiazkiewicz, Magdalena; Grzela, Dawid P.; Walczak, Maciej P.; Banaszczyk, Mateusz; Peciak, Joanna; Stoczynska-Fidelus, Ewelina; Rieske, Piotr

    2016-01-01

    The Epidermal Growth Factor Receptor (EGFR) and its mutations contribute in various ways to tumorigenesis and biology of human cancers. They are associated with tumor proliferation, progression, drug resistance and the process of apoptosis. There are also reports that overexpression and activation of wild-type EGFR may lead to cell apoptosis. To study this phenomenon, we overexpressed in an AD293 cell line two most frequently observed forms of the EGFR receptor: wild-type and the constitutively active mutant–EGFR variant III (EGFRvIII). Then, we compared the effect of EGF stimulation on cell viability and downstream EGFR signaling. AD293 cells overexpressing wild-type EGFR, despite a significant proliferation increase in serum supplemented medium, underwent apoptosis after EGF stimulation in serum free conditions. EGFRvIII expressing cells, however, were unaffected by either serum starvation or EGF treatment. The effect of EGF was completely neutralized by tyrosine kinase inhibitors (TKIs), indicating the specificity of this observation. Moreover, apoptosis was not prevented by inhibiting EGFR downstream proteins (PI3K, AKT and mTOR). Here we showed another EGFR function, dependent on environmental factors, which could be employed in therapy and drug design. We also proposed a new tool for EGFR inhibitor analysis. PMID:27153109

  7. Ghrelin promotes intestinal epithelial cell proliferation through PI3K/Akt pathway and EGFR trans-activation both converging to ERK 1/2 phosphorylation.

    PubMed

    Waseem, Talat; Duxbury, Mark; Ashley, Stanley W; Robinson, Malcolm K

    2014-02-01

    Little is known about ghrelin's effects on intestinal epithelial cells even though it is known to be a mitogen for a variety of other cell types. Because ghrelin is released in close proximity to the proliferative compartment of the intestinal tract, we hypothesized that ghrelin may have potent pro-proliferative effect on intestinal epithelial cells as well. To test this hypothesis, we characterized the effects of ghrelin on FHs74Int and Caco-2 intestinal epithelial cell lines in vitro. We found that ghrelin has potent dose dependent proliferative effects in both cell lines through a yet to be characterized G protein coupled growth hormone secretagogue receptor (GHS-R) subtype. Consistent with above findings, cell cycle flowcytometric analyses demonstrated that ghrelin shifts cells from the G1 to S phase and thereby promotes cell cycle progression. Further characterization of subcellular events, suggested that ghrelin mediates its pro-proliferative effect through Adenylate cyclase (AC)-independent epidermal growth factor receptor (EGFR) trans-activation and PI3K-Akt phosphorylation. Both these pathways converge to stimulate MAPK, ERK 1/2 downstream. The role of ghrelin in states where intestinal mucosal injury and rapid mucosal repair occur warrants further investigation.

  8. 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

  9. 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

  10. 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.

  11. 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

  12. 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

  13. 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

  14. 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.

  15. Honokiol induces autophagy of neuroblastoma cells through activating the PI3K/Akt/mTOR and endoplasmic reticular stress/ERK1/2 signaling pathways and suppressing cell migration.

    PubMed

    Yeh, Poh-Shiow; Wang, Weu; Chang, Ya-An; Lin, Chien-Ju; Wang, Jhi-Joung; Chen, Ruei-Ming

    2016-01-01

    In children, neuroblastomas are the most common and deadly solid tumor. Our previous study showed that honokiol, a small-molecule polyphenol, can traverse the blood-brain barrier and kill neuroblastoma cells. In this study, we further investigated the mechanisms of honokiol-induced insults to neuroblastoma cells. Treatment of neuroblastoma neuro-2a cells with honokiol elevated the levels of microtubule-associated protein light chain 3 (LC3)-II and induced cell autophagy in time- and concentration-dependent manners. Interestingly, pretreatment with 3-methyladenine (3-MA), an inhibitor of autophagy, led to the simultaneous attenuation of honokiol-induced cell autophagy and apoptosis but did not influence cell necrosis. As to the mechanisms, exposure of neuro-2a cells to honokiol time-dependently decreased the amount of phosphatidylinositol 3-kinase (PI3K). Sequentially, honokiol downregulated phosphorylation of protein kinase B (Akt) and mammalian target of rapamycin (mTOR) in neuro-2a cells. Furthermore, honokiol elevated the levels of glucose-regulated protein (GpR)78, an endoplasmic reticular stress (ERS)-associated protein, and amounts of intracellular reactive oxygen species (ROS). In contrast, reducing production of intracellular ROS using N-acetylcysteine, a scavenger of ROS, concurrently suppressed honokiol-induced cellular autophagy. Consequently, honokiol stimulated phosphorylation of extracellular signal-regulated kinase (ERK)1/2. However, pretreatment of neuro-2a cells with PD98059, an inhibitor of ERK1/2, lowered honokiol-induced autophagy. The effects of honokiol on inducing autophagy and apoptosis of neuroblastoma cells were further confirmed using mouse neuroblastoma NB41A3 cells as our experimental model. Fascinatingly, treatment of neuroblastoma neuro-2a and NB41A3 cells with honokiol for 12 h did not affect cell autophagy or apoptosis but caused significant suppression of cell migration. Taken together, this study showed that honokiol can induce

  16. Honokiol induces autophagy of neuroblastoma cells through activating the PI3K/Akt/mTOR and endoplasmic reticular stress/ERK1/2 signaling pathways and suppressing cell migration.

    PubMed

    Yeh, Poh-Shiow; Wang, Weu; Chang, Ya-An; Lin, Chien-Ju; Wang, Jhi-Joung; Chen, Ruei-Ming

    2016-01-01

    In children, neuroblastomas are the most common and deadly solid tumor. Our previous study showed that honokiol, a small-molecule polyphenol, can traverse the blood-brain barrier and kill neuroblastoma cells. In this study, we further investigated the mechanisms of honokiol-induced insults to neuroblastoma cells. Treatment of neuroblastoma neuro-2a cells with honokiol elevated the levels of microtubule-associated protein light chain 3 (LC3)-II and induced cell autophagy in time- and concentration-dependent manners. Interestingly, pretreatment with 3-methyladenine (3-MA), an inhibitor of autophagy, led to the simultaneous attenuation of honokiol-induced cell autophagy and apoptosis but did not influence cell necrosis. As to the mechanisms, exposure of neuro-2a cells to honokiol time-dependently decreased the amount of phosphatidylinositol 3-kinase (PI3K). Sequentially, honokiol downregulated phosphorylation of protein kinase B (Akt) and mammalian target of rapamycin (mTOR) in neuro-2a cells. Furthermore, honokiol elevated the levels of glucose-regulated protein (GpR)78, an endoplasmic reticular stress (ERS)-associated protein, and amounts of intracellular reactive oxygen species (ROS). In contrast, reducing production of intracellular ROS using N-acetylcysteine, a scavenger of ROS, concurrently suppressed honokiol-induced cellular autophagy. Consequently, honokiol stimulated phosphorylation of extracellular signal-regulated kinase (ERK)1/2. However, pretreatment of neuro-2a cells with PD98059, an inhibitor of ERK1/2, lowered honokiol-induced autophagy. The effects of honokiol on inducing autophagy and apoptosis of neuroblastoma cells were further confirmed using mouse neuroblastoma NB41A3 cells as our experimental model. Fascinatingly, treatment of neuroblastoma neuro-2a and NB41A3 cells with honokiol for 12 h did not affect cell autophagy or apoptosis but caused significant suppression of cell migration. Taken together, this study showed that honokiol can induce

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. Upregulation of HIF-1α via activation of ERK and PI3K pathway mediated protective response to microwave-induced mitochondrial injury in neuron-like cells.

    PubMed

    Zhao, Li; Yang, Yue-Feng; Gao, Ya-Bing; Wang, Shui-Ming; Wang, Li-Feng; Zuo, Hong-Yan; Dong, Ji; Xu, Xin-Ping; Su, Zhen-Tao; Zhou, Hong-Mei; Zhu, Ling-Ling; Peng, Rui-Yun

    2014-12-01

    Microwave-induced learning and memory deficits in animal models have been gaining attention in recent years, largely because of increasing public concerns on growing environmental influences. The data from our group and others have showed that the injury of mitochondria, the major source of cellular adenosine triphosphate (ATP) in primary neurons, could be detected in the neuron cells of microwave-exposed rats. In this study, we provided some insights into the cellular and molecular mechanisms behind mitochondrial injury in PC12 cell-derived neuron-like cells. PC12 cell-derived neuron-like cells were exposed to 30 mW/cm(2) microwave for 5 min, and damages of mitochondrial ultrastructure could be observed by using transmission electron microscopy. Impairments of mitochondrial function, indicated by decrease of ATP content, reduction of succinate dehydrogenase (SDH) and cytochrome c oxidase (COX) activities, decrease of mitochondrial membrane potential (MMP), and increase of reactive oxygen species (ROS) production, could be detected. We also found that hypoxia-inducible factor-1 (HIF-1α), a key regulator responsible for hypoxic response of the mammalian cells, was upregulated in microwave-exposed neuron-like cells. Furthermore, HIF-1α overexpression protected mitochondria from injury by increasing the ATP contents and MMP, while HIF-1α silence promoted microwave-induced mitochondrial damage. Finally, we demonstrated that both ERK and PI3K signaling activation are required in microwave-induced HIF-1α activation and protective response. In conclusion, we elucidated a regulatory connection between impairments of mitochondrial function and HIF-1α activation in microwave-exposed neuron-like cells. By modulating mitochondrial function and protecting neuron-like cells against microwave-induced mitochondrial injury, HIF-1α represents a promising therapeutic target for microwave radiation injury.

  4. 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.

  5. The phosphoinositide 3-kinase signaling pathway in normal and malignant B cells: activation mechanisms, regulation and impact on cellular functions.

    PubMed

    Pauls, Samantha D; Lafarge, Sandrine T; Landego, Ivan; Zhang, Tingting; Marshall, Aaron J

    2012-01-01

    The phosphoinositide 3-kinase (PI3K) pathway is a central signal transduction axis controlling normal B cell homeostasis and activation in humoral immunity. The p110δ PI3K catalytic subunit has emerged as a critical mediator of multiple B cell functions. The activity of this pathway is regulated at multiple levels, with inositol phosphatases PTEN and SHIP both playing critical roles. When deregulated, the PI3K pathway can contribute to B cell malignancies and autoantibody production. This review summarizes current knowledge on key mechanisms that activate and regulate the PI3K pathway and influence normal B cell functional responses including the development of B cell subsets, antigen presentation, immunoglobulin isotype switch, germinal center responses, and maintenance of B cell anergy. We also discuss PI3K pathway alterations reported in select B cell malignancies and highlight studies indicating the functional significance of this pathway in malignant B cell survival and growth within tissue microenvironments. Finally, we comment on early clinical trial results, which support PI3K inhibition as a promising treatment of chronic lymphocytic leukemia.

  6. Novel PI3K/AKT targeting anti-angiogenic activities of 4-vinylphenol, a new therapeutic potential of a well-known styrene metabolite

    PubMed Central

    Yue, Grace Gar-Lee; Lee, Julia Kin-Ming; Kwok, Hin-Fai; Cheng, Ling; Wong, Eric Chun-Wai; Jiang, Lei; Yu, Hua; Leung, Hoi-Wing; Wong, Yuk-Lau; Leung, Ping-Chung; Fung, Kwok-Pui; Lau, Clara Bik-San

    2015-01-01

    The pneumo- and hepato-toxicity of 4-vinylphenol (4VP), a styrene metabolite, has been previously reported. Nevertheless, the present study reported the novel anti-angiogenic activities of 4VP which was firstly isolated from the aqueous extract of a Chinese medicinal herb Hedyotis diffusa. Our results showed that 4VP at non-toxic dose effectively suppressed migration, tube formation, adhesion to extracellular matrix proteins, as well as protein and mRNA expressions of metalloproteinase-2 of human endothelial cells (HUVEC and HMEC-1). Investigation of the signal transduction revealed that 4VP down-regulated PI3K/AKT and p38 MAPK. Besides, 4VP interfered with the phosphorylation of ERK1/2, the translocation and expression of NFkappaB. In zebrafish embryo model, the new blood vessel growth was significantly blocked by 4VP (6.25–12.5 μg/mL medium). The VEGF-induced blood vessel formation in Matrigel plugs in C57BL/6 mice was suppressed by 4VP (20–100 μg/mL matrigel). In addition, the blood vessel number and tumor size were reduced by intraperitoneal 4VP (0.2–2 mg/kg) in 4T1 breast tumor-bearing BALB/c mice, with doxorubicin as positive control. Together, the in vitro and in vivo anti-angiogenic activities of 4VP were demonstrated for the first time. These findings suggest that 4VP has great potential to be further developed as an anti-angiogenic agent. PMID:26053458

  7. Lentiviral shRNA against KCa3.1 inhibits allergic response in allergic rhinitis and suppresses mast cell activity via PI3K/AKT signaling pathway

    PubMed Central

    Lin, Hai; Zheng, Chunquan; Li, Jing; Yang, Chen; Hu, Li

    2015-01-01

    Calcium-activated potassium ion channel-3.1 (KCa3.1) plays a pivotal role in the potassium-calcium exchange involved in atopy. This study aimed to explore the impact of lentiviral-mediated shRNA silencing KCa3.1 on allergic response in a murine allergic rhinitis (AR) model. The BALB/c mice were divided into four groups: untreated AR group, negative control AR group, lentiviral KCa3.1-shRNA treated AR group and normal control group. Concentrations of ovalbumin (OVA)-specific IgE, histamine and leukotrienes C4 (LTC4) in serum, and IL-4, IL-9 and IL-17 in nasal lavage fluid (NLF) were analyzed. Goblet cells and mast cells were counted. KCa3.1 positive cells were counted after immunolabelling by immunofluorescence method. KCa3.1, Mucin 5AC (MUC5AC), and tryptase mRNA levels were determined using real-time polymerase chain reaction. Furthermore, P815 cell line was used to explore the role and mechanism of lentiviral KCa3.1-shRNA on mast cells. The results showed that LV-KCa3.1-shRNA intervention effectively attenuated allergic responses in LV-KCa3.1-shRNA treated mice. LV-KCa3.1-shRNA intervention effectively suppressed KCa3.1 levels and phosphorylation of AKT in P815 cells, leading to the downregulation of tryptase, IL-6 and IL-8 levels. LV-KCa3.1-shRNA intervention effectively attenuated the allergic responses in AR and suppressed mast cell activity by inhibiting PI3K/AKT signaling pathway. PMID:26272420

  8. Impact of PI3K/AKT/mTOR pathway activation on the prognosis of patients with head and neck squamous cell carcinomas

    PubMed Central

    Álvarez-Teijeiro, Saúl; Hermida-Prado, Francisco; Santamaría, Iñigo; Allonca, Eva; Suárez-Fernández, Laura; Gonzalez, Maria Victoria; Balbín, Milagros; Astudillo, Aurora; Martínez-Camblor, Pablo; Su, Gloria H.; Rodrigo, Juan Pablo; García-Pedrero, Juana María

    2016-01-01

    The PI3K/AKT/mTOR signaling pathway has emerged as one of the most frequently deregulated in head and neck squamous cell carcinomas (HNSCC). Numerous alterations of various upstream and downstream components have been described; however, their prognostic significance and impact on HNSCC patient survival remains to be established. This was addressed using an unbiased cohort of 93 consecutive and homogeneous surgically treated HNSCC patients and results confirmed in 432 HNSCC patients. Our findings reveal the high prevalence of S6 phosphorylation, a surrogate marker of mTORC1 activation, in HNSCC specimens (>70%) and, more importantly, demonstrate its relevance on clinical outcome. Phosphorylation of ribosomal protein S6 on either Ser235/236 or Ser240/244 was consistently and significantly correlated with favorable prognosis, although with differences depending on the tumor site. Thus, p-S6 expression was significantly correlated with better disease-specific survival specifically in the subgroup of laryngeal carcinoma patients (P< 0.001). In addition, multivariate regression models revealed p-S6 to be an inverse and independent predictor of lymph-node metastasis (P= 0.004) and distant metastasis (P= 0.006). Taken together, this study unveils an unprecedented correlation of mTOR activation with improved clinical outcome in patients with laryngeal carcinomas and uncovers the potential of p-S6 expression as a good prognostic biomarker and an inverse predictor of lymph node and distant metastases. These results should be of broad interest as immunohistochemical detection of p-S6 may help to stratify patients and guide treatment decisions. PMID:27119232

  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. Protracted upregulation of leptin and IGF1 is associated with activation of PI3K/Akt and JAK2 pathway in mouse intestine after ionizing radiation exposure.

    PubMed

    Suman, Shubhankar; Kallakury, Bhaskar V S; Fornace, Albert J; Datta, Kamal

    2015-01-01

    Ionizing radiation is a known risk factor for gastrointestinal (GI) pathologies including cancer. Hormones and related signaling crosstalk, which could contribute to radiation-induced persistent pathophysiologic changes in the small intestine and colon, remain to be explored. The current study assessed perturbation of GI homeostasis-related hormones and signaling pathways at the systemic as well as at the tissue level in small intestine and colon. Mice (6-8 week old C57BL/6J) were exposed to 2 Gy γ radiation, serum and tissue samples were collected, and insulin like growth factor 1 (IGF-1) and leptin signaling were assessed two or twelve months after radiation exposure. Serum levels of IGF-1, IGF binding protein 3 (IGFBP3), leptin, and adiponectin were altered at these times after irradiation. Radiation was associated with increased IGF1 receptor (IGF1R) and obesity (leptin) receptor (Ob-R), decreased adiponectin receptor 1 (Adipo-R1) and 2 (Adipo-R2), and increased Ki-67 levels in small intestine and colon at both time points. Immunoblot analysis further showed increased IGF1R and Ob-R, and decreased Adipo-R2. Additionally, upregulation of PI3K/Akt and JAK2 signaling, which are downstream of IGF1 and leptin, was also observed in irradiated samples at both time points. These results when considered along with increased cell proliferation in the small intestine and colon demonstrate for the first time that ionizing radiation can persistently increase IGF1 and leptin and activate downstream proliferative pathways, which may contribute to GI functional alterations and carcinogenesis.

  11. Activation of the PI3K/Akt signal transduction pathway and increased levels of insulin receptor in protein repair-deficient mice.

    PubMed

    Farrar, Christine; Houser, Carolyn R; Clarke, Steven

    2005-02-01

    Protein L-isoaspartate (D-aspartate) O-methyltransferase is an enzyme that catalyses the repair of isoaspartyl damage in proteins. Mice lacking this enzyme (Pcmt1-/- mice) have a progressive increase in brain size compared with wild-type mice (Pcmt1+/+ mice), a phenotype that can be associated with alterations in the PI3K/Akt signal transduction pathway. Here we show that components of this pathway, including Akt, GSK3beta and PDK-1, are more highly phosphorylated in the brains of Pcmt1-/- mice, particularly in cells of the hippocampus, in comparison with Pcmt1+/+ mice. Examination of upstream elements of this pathway in the hippocampus revealed that Pcmt1-/- mice have increased activation of insulin-like growth factor-I (IGF-I) receptor and/or insulin receptor. Western blot analysis revealed an approximate 200% increase in insulin receptor protein levels and an approximate 50% increase in IGF-I receptor protein levels in the hippocampus of Pcmt1-/- mice. Higher levels of the insulin receptor protein were also found in other regions of the adult brain and in whole tissue extracts of brain, liver, heart and testes of both juvenile and adult Pcmt1-/- mice. There were no significant differences in plasma insulin levels for adult Pcmt1-/- mice during glucose tolerance tests. However, they did show higher peak levels of blood glucose, suggesting a mild impairment in glucose tolerance. We propose that Pcmt1-/- mice have altered regulation of the insulin pathway, possibly as a compensatory response to altered glucose uptake or metabolism or as an adaptive response to a general accumulation of isoaspartyl protein damage in the brain and other tissues.

  12. Oxidized LDL at low concentration promotes in-vitro angiogenesis and activates nitric oxide synthase through PI3K/Akt/eNOS pathway in human coronary artery endothelial cells

    SciTech Connect

    Yu, Shan; Wong, Siu Ling; Lau, Chi Wai; Huang, Yu; Yu, Cheuk-Man

    2011-04-01

    Research highlights: {yields} Low-concentration oxidized LDL enhances angiogenesis through nitric oxide (NO). {yields} Oxidized LDL increases intracellular NO levels via eNOS phosphorylation. {yields} Akt/PI3K signaling mediates oxidized LDL-induced eNOS phosphorylation. -- Abstract: It has long been considered that oxidized low-density lipoprotein (oxLDL) causes endothelial dysfunction and is remarkably related to the development of atherosclerosis. However, the effect of oxLDL at very low concentration (<10 {mu}g/ml) on the endothelial cells remains speculative. Nitric oxide (NO) has a crucial role in the endothelial cell function. In this study, we investigated the effect of oxLDL at low concentration on NO production and proliferation, migration, tube formation of the human coronary artery endothelial cells (HCAEC). Results showed that oxLDL at 5 {mu}g/ml enhanced HCAEC proliferation, migration and tube formation. These phenomena were accompanied by an increased intracellular NO production. L-NAME (a NOS inhibitor), LY294002 and wortmannin (PI3K inhibitors) could abolish oxLDL-induced angiogenic effects and prevent NO production in the HCAEC. The phosphorylation of Akt, PI3K and eNOS were up-regulated by oxLDL, which was attenuated by LY294002. Our results suggested that oxLDL at low concentration could promote in-vitro angiogenesis and activate nitric oxide synthesis through PI3K/Akt/eNOS pathway in HCAEC.

  13. Antitumor activity of pimasertib, a selective MEK 1/2 inhibitor, in combination with PI3K/mTOR inhibitors or with multi-targeted kinase inhibitors in pimasertib-resistant human lung and colorectal cancer cells.

    PubMed

    Martinelli, Erika; Troiani, Teresa; D'Aiuto, Elena; Morgillo, Floriana; Vitagliano, Donata; Capasso, Anna; Costantino, Sarah; Ciuffreda, Loreta Pia; Merolla, Francesco; Vecchione, Loredana; De Vriendt, Veerle; Tejpar, Sabine; Nappi, Anna; Sforza, Vincenzo; Martini, Giulia; Berrino, Liberato; De Palma, Raffaele; Ciardiello, Fortunato

    2013-11-01

    The RAS/RAF/MEK/MAPK and the PTEN/PI3K/AKT/mTOR pathways are key regulators of proliferation and survival in human cancer cells. Selective inhibitors of different transducer molecules in these pathways have been developed as molecular targeted anti-cancer therapies. The in vitro and in vivo anti-tumor activity of pimasertib, a selective MEK 1/2 inhibitor, alone or in combination with a PI3K inhibitor (PI3Ki), a mTOR inhibitor (everolimus), or with multi-targeted kinase inhibitors (sorafenib and regorafenib), that block also BRAF and CRAF, were tested in a panel of eight human lung and colon cancer cell lines. Following pimasertib treatment, cancer cell lines were classified as pimasertib-sensitive (IC50 for cell growth inhibition of 0.001 µM) or pimasertib-resistant. Evaluation of basal gene expression profiles by microarrays identified several genes that were up-regulated in pimasertib-resistant cancer cells and that were involved in both RAS/RAF/MEK/MAPK and PTEN/PI3K/AKT/mTOR pathways. Therefore, a series of combination experiments with pimasertib and either PI3Ki, everolimus, sorafenib or regorafenib were conducted, demonstrating a synergistic effect in cell growth inhibition and induction of apoptosis with sustained blockade in MAPK- and AKT-dependent signaling pathways in pimasertib-resistant human colon carcinoma (HCT15) and lung adenocarcinoma (H1975) cells. Finally, in nude mice bearing established HCT15 and H1975 subcutaneous tumor xenografts, the combined treatment with pimasertib and BEZ235 (a dual PI3K/mTOR inhibitor) or with sorafenib caused significant tumor growth delays and increase in mice survival as compared to single agent treatment. These results suggest that dual blockade of MAPK and PI3K pathways could overcome intrinsic resistance to MEK inhibition.

  14. 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

  15. 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

  16. 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

  17. Cadmium induces carcinogenesis in BEAS-2B cells through ROS-dependent activation of PI3K/AKT/GSK-3β/β-catenin signaling

    SciTech Connect

    Son, Young-Ok; Wang, Lei; Poyil, Pratheeshkumar; Budhraja, Amit; Hitron, J. Andrew; Zhang, Zhuo; Lee, Jeong-Chae; Shi, Xianglin

    2012-10-15

    Cadmium has been widely used in industry and is known to be carcinogenic to humans. Although it is widely accepted that chronic exposure to cadmium increases the incidence of cancer, the mechanisms underlying cadmium-induced carcinogenesis are unclear. The main aim of this study was to investigate the role of reactive oxygen species (ROS) in cadmium-induced carcinogenesis and the signal transduction pathways involved. Chronic exposure of human bronchial epithelial BEAS-2B cells to cadmium induced cell transformation, as evidenced by anchorage-independent growth in soft agar and clonogenic assays. Chronic cadmium treatment also increased the potential of these cells to invade and migrate. Injection of cadmium-stimulated cells into nude mice resulted in the formation of tumors. In contrast, the cadmium-mediated increases in colony formation, cell invasion and migration were prevented by transfection with catalase, superoxide dismutase-1 (SOD1), or SOD2. In particular, chronic cadmium exposure led to activation of signaling cascades involving PI3K, AKT, GSK-3β, and β-catenin and transfection with each of the above antioxidant enzymes markedly inhibited cadmium-mediated activation of these signaling proteins. Inhibitors specific for AKT or β-catenin almost completely suppressed the cadmium-mediated increase in total and active β-catenin proteins and colony formation. Moreover, there was a marked induction of AKT, GSK-3β, β-catenin, and carcinogenic markers in tumor tissues formed in mice after injection with cadmium-stimulated cells. Collectively, our findings suggest a direct involvement of ROS in cadmium-induced carcinogenesis and implicate a role of AKT/GSK-3β/β-catenin signaling in this process. -- Highlights: ► Chronic exposure to cadmium induces carcinogenic properties in BEAS-2B cells. ► ROS involved in cadmium-induced tumorigenicity of BEAS-2B cells. ► Cadmium activates ROS-dependent AKT/GSK-3β/β-catenin-mediated signaling. ► ROS

  18. Umbilical cord tissue-derived mesenchymal stem cells induce apoptosis in PC-3 prostate cancer cells through activation of JNK and downregulation of PI3K/AKT signaling

    PubMed Central

    2014-01-01

    Introduction Although mesenchymal stem cells (MSCs) have antitumor potential in hepatocellular carcinoma and breast cancer cells, the antitumor mechanism of human umbilical cord mesenchymal stem cells (hUCMSCs) in prostate cancer cells still remains unclear. Thus, in the present study, we elucidated the antitumor activity of hUCMSCs in PC-3 prostate cancer cells in vitro and in vivo. Methods hUCMSCs were isolated from Wharton jelly of umbilical cord and characterized via induction of differentiations, osteogenesis, and adipogenesis. Antitumor effects of UCMSCs on tumor growth were evaluated in a co-culture condition with PC-3 prostate cancer cells. PC-3 cells were subcutaneously (sc) injected into the left flank of nude mice, and UCMSCs were sc injected into the right flank of the same mouse. Results We found that hUCMSCs inhibited the proliferation of PC-3 cells in the co-culture condition. Furthermore, co-culture of hUCMSCs induced the cleavage of caspase 9/3 and PARP, activated c-jun NH2-terminal kinase (JNK), and Bax, and attenuated the phosphorylation of phosphatidylinositol 3-kinase (PI3K)/ AKT, extracellular signal-regulated kinase (ERK), and the expression of survival genes such as Bcl-2, Bcl-xL, Survivin, Mcl-1, and cIAP-1 in PC-3 cells in Western blotting assay. Conversely, we found that treatment of specific JNK inhibitor SP600125 suppressed the cleavages of caspase 9/3 and PARP induced by hUCMSCs in PC-3 cells by Western blotting and immunofluorescence assay. The homing of hUCMSCs to, and TUNEL-positive cells on, the K562 xenograft tumor region were detected in Nu/nu-BALB/c mouse. Conclusions These results suggest that UCMSCs inhibit tumor growth and have the antitumor potential for PC-3 prostate cancer treatment. PMID:24739733

  19. Porcine circovirus type 2 activates PI3K/Akt and p38 MAPK pathways to promote interleukin-10 production in macrophages via Cap interaction of gC1qR

    PubMed Central

    Wang, Tongtong; Zhang, Xiujuan; Chen, Yu; Cui, Beibei; Li, Delong; Zhao, Xiaomin; Zhang, Wenlong; Chang, Lingling; Tong, Dewen

    2016-01-01

    Porcine circovirus type 2 (PCV2) infection caused PCV2-associated diseases (PCVAD) is one of the major emerging immunosuppression diseases in pig industry. In this study, we investigated how PCV2 inoculation increases interleukin (IL)-10 expression in porcine alveolar macrophages (PAMs). PCV2 inoculation significantly upregulated IL-10 expression compared with PCV1. Upon initial PCV2 inoculation, PI3K/Akt cooperated with NF-κB pathways to promote IL-10 transcription via p50, CREB and Ap1 transcription factors, whereas inhibition of PI3K/Akt activation blocked Ap1 and CREB binding to the il10 promoter, and decreased the binding level of NF-κB1 p50 with il10 promoter, leading to great reduction in early IL-10 transcription. In the later phase of inoculation, PCV2 further activated p38 MAPK and ERK pathways to enhance IL-10 production by promoting Sp1 binding to the il10 promoter. For PCV2-induced IL-10 production in macrophages, PCV2 capsid protein Cap, but not the replicase Rep or ORF3, was the critical component. Cap activated PI3K/Akt, p38 MAPK, and ERK signaling pathways to enhance IL-10 expression. In the whole process, gC1qR mediated PCV2-induced PI3K/Akt and p38 MAPK activation to enhance IL-10 induction by interaction with Cap. Depletion of gC1qR blocked PI3K/Akt and p38 MAPK activation, resulting in significant decrease in IL-10 production in PCV2-inoculated cells. Thus, gC1qR might be a critical functional receptor for PCV2-induced IL-10 production. Taken together, these data demonstrated that Cap protein binding with host gC1qR induction of PI3K/Akt and p38 MAPK signalings activation is a critical process in enhancing PCV2-induced IL-10 production in porcine alveolar macrophages. PMID:26883107

  20. Porcine circovirus type 2 activates PI3K/Akt and p38 MAPK pathways to promote interleukin-10 production in macrophages via Cap interaction of gC1qR.

    PubMed

    Du, Qian; Huang, Yong; Wang, Tongtong; Zhang, Xiujuan; Chen, Yu; Cui, Beibei; Li, Delong; Zhao, Xiaomin; Zhang, Wenlong; Chang, Lingling; Tong, Dewen

    2016-04-01

    Porcine circovirus type 2 (PCV2) infection caused PCV2-associated diseases (PCVAD) is one of the major emerging immunosuppression diseases in pig industry. In this study, we investigated how PCV2 inoculation increases interleukin (IL)-10 expression in porcine alveolar macrophages (PAMs). PCV2 inoculation significantly upregulated IL-10 expression compared with PCV1. Upon initial PCV2 inoculation, PI3K/Akt cooperated with NF-κB pathways to promote IL-10 transcription via p50, CREB and Ap1 transcription factors, whereas inhibition of PI3K/Akt activation blocked Ap1 and CREB binding to the il10 promoter, and decreased the binding level of NF-κB1 p50 with il10 promoter, leading to great reduction in early IL-10 transcription. In the later phase of inoculation, PCV2 further activated p38 MAPK and ERK pathways to enhance IL-10 production by promoting Sp1 binding to the il10 promoter. For PCV2-induced IL-10 production in macrophages, PCV2 capsid protein Cap, but not the replicase Rep or ORF3, was the critical component. Cap activated PI3K/Akt, p38 MAPK, and ERK signaling pathways to enhance IL-10 expression. In the whole process, gC1qR mediated PCV2-induced PI3K/Akt and p38 MAPK activation to enhance IL-10 induction by interaction with Cap. Depletion of gC1qR blocked PI3K/Akt and p38 MAPK activation, resulting in significant decrease in IL-10 production in PCV2-inoculated cells. Thus, gC1qR might be a critical functional receptor for PCV2-induced IL-10 production. Taken together, these data demonstrated that Cap protein binding with host gC1qR induction of PI3K/Akt and p38 MAPK signalings activation is a critical process in enhancing PCV2-induced IL-10 production in porcine alveolar macrophages. PMID:26883107

  1. Inhibition of fatty acid synthase suppresses U-2 OS cell invasion and migration via downregulating the activity of HER2/PI3K/AKT signaling pathway in vitro

    SciTech Connect

    Wang, Tao Fang; Wang, Heng; Peng, Ai Fen; Luo, Qing Feng; Liu, Zhi Li; Zhou, Rong Ping; Gao, Song; Zhou, Yang; Chen, Wen Zhao

    2013-10-18

    Highlights: •We investigate the relationship between FASN and HER2 or p-HER2 by IHC in OS tissues. •We construct FASN-specific RNAi plasmid. •Inhibiting FASN down-regulates HER2/PI3K/AKT cell signaling in U-2 OS. •Inhibiting FASN blocks U-2 OS cell invasion and migration. -- Abstract: FASN plays an important role in the malignant phenotype of various tumors. Our previous studies show that inhibition FASN could induce apoptosis and inhibit proliferation in human osteosarcoma (OS) cell in vivo and vitro. The aim in this study was to investigate the effect of inhibition FASN on the activity of HER2/PI3K/AKT axis and invasion and migration of OS cell. The expression of FASN, HER2 and p-HER2(Y1248) proteins was detected by immunohistochemistry in OS tissues from 24 patients with pulmonary metastatic disease, and the relationship between FASN and p-HER2 as well as HER2 was investigated. The results showed that there was a positive correlation between FASN and HER2 as well as p-HER2 protein expression. The U-2 OS cells were transfected with either the FASN specific RNAi plasmid or the negative control RNAi plasmid. FASN mRNA was measured by RT-PCR. Western blot assays was performed to examine the protein expression of FASN, HER2, p-HER2(Y1248), PI3K, Akt and p-Akt (Ser473). Migration and invasion of cells were investigated by wound healing and transwell invasion assays. The results showed that the activity of HER2/PI3K/AKT signaling pathway was suppressed by inhibiting FASN. Meanwhile, the U-2OS cells migration and invasion were also impaired by inhibiting the activity of FASN/HER2/PI3K/AKT. Our results indicated that inhibition of FASN suppresses OS cell invasion and migration via down-regulation of the “HER2/PI3K/AKT” axis in vitro. FASN blocker may be a new therapeutic strategy in OS management.

  2. 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

  3. 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.

  4. Subtoxic N-methyl-D-aspartate delayed neuronal death in ischemic brain injury through TrkB receptor- and calmodulin-mediated PI-3K/Akt pathway activation.

    PubMed

    Xu, Jing; Zhang, Quan-Guang; Li, Chong; Zhang, Guang-Yi

    2007-01-01

    Previous studies have shown that subtoxic NMDA moderated the neuronal survival in vitro and vivo. We performed this experiment to clarify the precise mechanism underlie subtoxic NMDA delayed neuronal death in ischemic brain injury. We found that pretreatment of NMDA (100 mg/kg) increased the number of the surviving CA1 pyramidal cells of hippocampus at 5 days of reperfusion. This dose of NMDA could also enhance Akt activation after ischemia/reperfusion (I/R). Here, we examined the possible mechanism that NMDA induced Akt activation. On the one hand, we found NMDA receptor-mediated Akt activation was associated with increased expression of BDNF (brain-derived neurotrophic factor) and activation of its high-affinity receptor TrkB after I/R in the hippocampus CA1 region, which could be held down by TrkB receptor antagonist K252a. On the other hand, we found that NMDA enhanced the binding of Ca2+-dependent calmodulin (CaM) to p85 (the regulation subunit of PI-3K), which led to the activation of Akt. W-13, an active CaM inhibitor, prevented the combination of CaM and p85 and subsequent Akt activation. Furthermore, NMDA receptor-mediated Akt activation was reversed by combined treatment with LY294002, the specific blockade of PI-3K. Taken together, our results suggested that subtoxic NMDA exerts the neuroprotective effect via activation of prosurvival PI-3K/Akt pathway against ischemic brain injury, and BDNF-TrkB signaling and Ca2+-dependent CaM cascade might contribute to NMDA induced activation of PI-3K/Akt pathway.

  5. 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

  6. 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

  7. The promotion of angiogenesis induced by three-dimensional porous beta-tricalcium phosphate scaffold with different interconnection sizes via activation of PI3K/Akt pathways

    PubMed Central

    Xiao, Xin; Wang, Wei; Liu, Dong; Zhang, Haoqiang; Gao, Peng; Geng, Lei; Yuan, Yulin; Lu, Jianxi; Wang, Zhen

    2015-01-01

    The porous architectural characteristics of biomaterials play an important role in scaffold revascularization. However, no consensus exists regarding optimal interconnection sizes for vascularization and its scaffold bioperformance with different interconnection sizes. Therefore, a series of disk-type beta-tricalcium phosphates with the same pore sizes and variable interconnections were produced to evaluate how the interconnection size influenced biomaterial vascularization in vitro and in vivo. We incubated human umbilical vein endothelial cells on scaffolds with interconnections of various sizes. Results showed that scaffolds with a 150 μm interconnection size ameliorated endothelial cell function evidenced by promoting cell adhesion and migration, increasing cell proliferation and enhancing expression of platelet-endothelial cell adhesion molecules and vascular endothelial growth factor. In vivo study was performed on rabbit implanted with scaffolds into the bone defect on femoral condyles. Implantation with scaffolds with 150 μm interconnection size significantly improved neovascularization as shown by micro-CT as compared to scaffolds with 100 and 120 μm interconnection sizes. Moreover, the aforementioned positive effects were abolished by blocking PI3K/Akt/eNOS pathway with LY-294002. Our study explicitly demonstrates that the scaffold with 150 μm interconnection size improves neovascularization via the PI3K/Akt pathway and provides a target for biomaterial inner structure modification to attain improved clinical performance in implant vascularization. PMID:25797242

  8. The promotion of angiogenesis induced by three-dimensional porous beta-tricalcium phosphate scaffold with different interconnection sizes via activation of PI3K/Akt pathways.

    PubMed

    Xiao, Xin; Wang, Wei; Liu, Dong; Zhang, Haoqiang; Gao, Peng; Geng, Lei; Yuan, Yulin; Lu, Jianxi; Wang, Zhen

    2015-01-01

    The porous architectural characteristics of biomaterials play an important role in scaffold revascularization. However, no consensus exists regarding optimal interconnection sizes for vascularization and its scaffold bioperformance with different interconnection sizes. Therefore, a series of disk-type beta-tricalcium phosphates with the same pore sizes and variable interconnections were produced to evaluate how the interconnection size influenced biomaterial vascularization in vitro and in vivo. We incubated human umbilical vein endothelial cells on scaffolds with interconnections of various sizes. Results showed that scaffolds with a 150 μm interconnection size ameliorated endothelial cell function evidenced by promoting cell adhesion and migration, increasing cell proliferation and enhancing expression of platelet-endothelial cell adhesion molecules and vascular endothelial growth factor. In vivo study was performed on rabbit implanted with scaffolds into the bone defect on femoral condyles. Implantation with scaffolds with 150 μm interconnection size significantly improved neovascularization as shown by micro-CT as compared to scaffolds with 100 and 120 μm interconnection sizes. Moreover, the aforementioned positive effects were abolished by blocking PI3K/Akt/eNOS pathway with LY-294002. Our study explicitly demonstrates that the scaffold with 150 μm interconnection size improves neovascularization via the PI3K/Akt pathway and provides a target for biomaterial inner structure modification to attain improved clinical performance in implant vascularization.

  9. Interleukin-8 upregulates integrin β3 expression and promotes estrogen receptor-negative breast cancer cell invasion by activating the PI3K/Akt/NF-κB pathway.

    PubMed

    Shao, Nan; Lu, Zhenhai; Zhang, Yunjian; Wang, Mian; Li, Wen; Hu, Ziye; Wang, Shenming; Lin, Ying

    2015-08-10

    Interleukin-8 (IL-8) possesses tumorigenic and proangiogenic properties and is overexpressed in many human cancers. The integrin family regulates a diverse array of cellular functions crucial to the initiation, progression and metastasis of solid tumors. However, the mechanisms of action of IL-8 and integrin in estrogen receptor-negative breast cancer are largely unknown. In this study, IL-8 and integrin β3 expression in human breast cancer cells and tissues was examined by real-time PCR, Western blot and immunochemistry analysis. Integrin β3 expression, invasive ability and the activation of PI3K/Akt and NF-κB pathways in IL-8 knockdown breast cancer cells were evaluated. In addition, reporter assay and ChIP were performed to assess integrin β3 promoter activity in IL-8 knockdown cells. We observed a positive correlation between integrin β3 and IL-8 expression, which was inversely correlated with ER status in breast cancer cell lines and tissues. IL-8 siRNA decreased the invasion and integrin β3 expression in human breast cancer cells. Moreover, IL-8 siRNA attenuated the phosphorylation of PI3K and Akt and inhibited NF-κB activity and binding on integrin β3 promoter. IL-8 siRNA diminished NF-κB nuclear translocation via blocking IκB phosphorylation in the cytoplasm. In conclusion, IL-8 activates the PI3K/Akt pathway, which in turn activates NF-κB, resulting in the upregulation of integrin β3 expression and increased invasion of estrogen receptor-negative breast cancer cells. IL-8/PI3K/Akt/NF-κB/integrin β3 axis may be exploited for therapeutic intervention to breast cancer metastasis.

  10. 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.

  11. 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.

  12. Activation of the PI3K-Akt pathway by human T cell leukemia virus type 1 (HTLV-1) oncoprotein Tax increases Bcl3 expression, which is associated with enhanced growth of HTLV-1-infected T cells

    SciTech Connect

    Saito, Kousuke; Saito, Mineki; Taniura, Naoko; Okuwa, Takako; Ohara, Yoshiro

    2010-08-01

    Bcl3 is a member of the I{kappa}B family that regulates genes involved in cell proliferation and apoptosis. Recent reports indicated that Bcl3 is overexpressed in HTLV-1-infected T cells via Tax-mediated transactivation, and acts as a negative regulator of viral transcription. However, the role of Bcl3 in cellular signal transduction and the growth of HTLV-1-infected T cells have not been reported. In this study, we showed that the knockdown of Bcl3 by short hairpin RNA inhibited the growth of HTLV-1-infected T cells. Although phosphatidylinositol-3 kinase (PI3K) inhibitor reduced Bcl3 expression, inactivation of glycogen synthase kinase 3 (GSK3), an effector kinase of the PI3K/Akt signaling pathway, restored Bcl3 expression in Tax-negative but not in Tax-positive T cells. Our results indicate that the overexpression of Bcl3 in HTLV-1-infected T cells is regulated not only by transcriptional but also by post-transcriptional mechanisms, and is involved in overgrowth of HTLV-1-infected T cells.

  13. PF-04691502, a dual PI3K/mTOR inhibitor has potent pre-clinical activity by inducing apoptosis and G1 cell cycle arrest in aggressive B-cell non-Hodgkin lymphomas.

    PubMed

    Chen, Deyu; Mao, Chaoming; Zhou, Yuepeng; Su, Yuting; Liu, Shenzha; Qi, Wen-Qing

    2016-01-01

    The PI3K/Akt/mTOR pathway is activated in a variety of human tumors including B-cell non-Hodgkin lymphoma (B-NHL). Targeting this pathway has been validated in solid and hematological tumors. In the present study, we demonstrated that PF-04691502, a novel PI3K/mTOR inhibitor has potent activity in a panel of aggressive B-NHL cell lines including diffuse large B-cell lymphoma (DLBCL) and mantle cell lymphoma (MCL). MTS analysis showed that PF-04691502 effectively inhibited cell proliferation with IC50 values ranging from 0.12 to 0.55 µM. Cells treated with PF-04691502 exhibited decreased phosphorylation of Akt and S6 ribosomal protein confirming the mechanism of action of a PI3K/mTOR inhibitor. Also, treatment of B-NHL cell lines with PF-04691502 induced apoptosis in a dose- and time-dependent manner. Moreover, PF-04691502 significantly induced G1 cell cycle arrest associated with a decrease in cyclin D1 which contributed to suppression of cell proliferation. Finally, rituximab enhanced apoptosis induced by PF-04691502. Taken together, our findings provide for the first time that PF-04691502 inhibits the constitutively activated PI3K/mTOR pathway in aggressive B-cell NHL cell lines associated with inhibition of cell cycle progression, cell proliferation and promotion of apoptosis. These findings suggest that PF-04691502 is a novel therapeutic strategy in aggressive B-cell NHL and warrants early phase clinical trial evaluation with and without rituximab. PMID:26549638

  14. 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

  15. 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.

  16. 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

  17. 3,5,3'-triiodothyronine (T3) stimulates cell proliferation through the activation of the PI3K/Akt pathway and reactive oxygen species (ROS) production in chick embryo hepatocytes.

    PubMed

    Gnocchi, Davide; Leoni, Silvia; Incerpi, Sandra; Bruscalupi, Giovannella

    2012-05-01

    Thyroid hormones (THs) have a wide variety of essential roles in vertebrates, ranging from the regulation of key metabolic processes to cell proliferation and apoptosis. The classical mechanism of action of THs is genomic; 3,5,3'-triiodothyronine (T3) binds to specific nuclear receptors (TRs) and modifies the expression of specific genes. Recently, a new category of mechanisms, termed nongenomic, has been discovered for T3. These mechanisms include, among others, the rapid activation of signal transduction pathways, such as PI3K/Akt and MAPK, which eventually lead to cell proliferation. These effects are mediated in some cell types by a plasma membrane receptor, identified as integrin αvβ3, and in other cell types by cytoplasmic TRβ1. The aim of this work was to analyze the effect of T3 on the cell growth of chick embryo hepatocytes at two different stages of development, 14 and 19 days, and to determine the activation of the signal transduction pathways, focusing on the potential involvement of a plasma membrane receptor and the possible participation of PI3K/Akt and reactive oxygen species (ROS). Our results clearly show that T3 stimulates cell proliferation at both stages of development through the activation of the PI3K/Akt pathway and the production of small amounts of ROS, which operate as effective second messengers. Moreover, we prove that these effects are not initiated at the plasma membrane receptor for T3.

  18. 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.

  19. 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

  20. NRBF2 Regulates Autophagy and Prevents Liver Injury by Modulating Atg14L-Linked Phosphatidylinositol-3 Kinase III Activity

    PubMed Central

    Lu, Jiahong; He, Liqiang; Behrends, Christian; Araki, Masatake; Araki, Kimi; Wang, Qing Jun; Catanzaro, Joseph M.; Friedman, Scott L.; Zong, Wei-Xing; Fiel, M. Isabel; Li, Min; Yue, Zhenyu

    2015-01-01

    The Beclin 1-Vps34 complex, the core component of the class III phosphatidylinositol-3 kinase (PI3K-III), binds Atg14L or UVRAG to control different steps of autophagy. However, the mechanism underlying the control of PI3K-III activity remains elusive. Here we report the identification of NRBF2 as a component in the specific PI3K-III complex and a modulator of PI3K-III activity. Through its MIT domain, NRBF2 binds Atg14L directly and enhances Atg14L-linked Vps34 kinase activity and autophagy induction. NRBF2 deficient cells exhibit enhanced vulnerability to ER stress that is reversed by re-introducing exogenous NRBF2. NRBF2 deficient mice develop focal liver necrosis and ductular reaction, accompanied by impaired Atg14L-linked Vps34 activity and autophagy, though the mice show no increased mortality. Our data reveals a key role for NRBF2 in the assembly of the specific Atg14L-Beclin 1-Vps34-Vps15 complex for autophagy induction. Thus, NRBF2 modulates autophagy via regulation of PI3K-III and prevents ER stress-mediated cytotoxicity and liver injury. PMID:24849286

  1. 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.

  2. TGF-β2 induces Grb2 to recruit PI3-K to TGF-RII that activates JNK/AP-1-signaling and augments invasiveness of Theileria-transformed macrophages.

    PubMed

    Haidar, Malak; Whitworth, Jessie; Noé, Gaelle; Liu, Wang Qing; Vidal, Michel; Langsley, Gordon

    2015-10-29

    Theileria-infected macrophages display many features of cancer cells such as heightened invasive capacity; however, the tumor-like phenotype is reversible by killing the parasite. Moreover, virulent macrophages can be attenuated by multiple in vitro passages and so provide a powerful model to elucidate mechanisms related to transformed macrophage virulence. Here, we demonstrate that in two independent Theileria-transformed macrophage cell lines Grb2 expression is down-regulated concomitant with loss of tumor virulence. Using peptidimer-c to ablate SH2 and SH3 interactions of Grb2 we identify TGF-receptor II and the p85 subunit of PI3-K, as Grb2 partners in virulent macrophages. Ablation of Grb2 interactions reduces PI3-K recruitment to TGF-RII and decreases PIP3 production, and dampens JNK phosphorylation and AP-1-driven transcriptional activity down to levels characteristic of attenuated macrophages. Loss of TGF-R>PI3-K>JNK>AP-1 signaling negatively impacts on virulence traits such as reduced JAM-L/ITG4A and Fos-B/MMP9 expression that contribute to virulent macrophage adhesion and invasiveness.

  3. 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

  4. Exposure to Ionizing Radiation Causes Long-Term Increase in Serum Estradiol and Activation of PI3K-Akt Signaling Pathway in Mouse Mammary Gland

    SciTech Connect

    Suman, Shubhankar; Johnson, Michael D.; Fornace, Albert J.; Datta, Kamal

    2012-10-01

    Purpose: Exposure to ionizing radiation is an established risk factor for breast cancer. Radiation exposure during infancy, childhood, and adolescence confers the highest risk. Although radiation is a proven mammary carcinogen, it remains unclear where it acts in the complex multistage process of breast cancer development. In this study, we investigated the long-term pathophysiologic effects of ionizing radiation at a dose (2 Gy) relevant to fractionated radiotherapy. Methods and Materials: Adolescent (6-8 weeks old; n = 10) female C57BL/6J mice were exposed to 2 Gy total body {gamma}-radiation, the mammary glands were surgically removed, and serum and urine samples were collected 2 and 12 months after exposure. Molecular pathways involving estrogen receptor-{alpha} (ER{alpha}) and phosphatidylinositol-3-OH kinase (PI3K)-Akt signaling were investigated by immunohistochemistry and Western blot. Results: Serum estrogen and urinary levels of the oncogenic estrogen metabolite (16{alpha}OHE1) were significantly increased in irradiated animals. Immunostaining for the cellular proliferative marker Ki-67 and cyclin-D1 showed increased nuclear accumulation in sections of mammary glands from irradiated vs. control mice. Marked increase in p85{alpha}, a regulatory sub-unit of the PI3K was associated with increase in Akt, phospho-Akt, phospho-BAD, phospho-mTOR, and c-Myc in irradiated samples. Persistent increase in nuclear ER{alpha} in mammary tissues 2 and 12 months after radiation exposure was also observed. Conclusions: Taken together, our data not only support epidemiologic observations associating radiation and breast cancer but also, specify molecular events that could be involved in radiation-induced breast cancer.

  5. PI3K/AKT signaling pathway plays a role in enhancement of eNOS activity by recombinant human angiotensin converting enzyme 2 in human umbilical vein endothelial cells

    PubMed Central

    Zhang, Yan; Wang, Shi-Jie; Han, Zhen-Hua; Li, Yong-Qin; Xue, Jia-Hong; Gao, Deng-Feng; Wu, Xiao-San; Wang, Cong-Xia

    2014-01-01

    The aim of this study was to investigate the effect of PI3K/AKT signaling pathway in the activity of recombinant human angiotensin converting enzyme 2 (rhACE2) promoted the activity of endothelial nitric oxide synthase (eNOS). The human umbilical vein endothelial cells (HUVEC) were cultured in vitro. Then treated with Ang II (1×10-6 mol/L) for 24 h. The rhACE2 (100 μmol/L) was added and incubated for 5, 10, 15, 30, 60 min respectively which was based on Ang II intervention. The effect of rhACE2 on phosphorylation eNOS level was also observed in the presence of LY294002 (10 μmol/L) (PI3K/AKT inhibitors). Griess reagent method was applied to measure NO contents in cell culture supernatant, RT-PCR to detect the expression of eNOSmRNA in HUVEC, and Western blot to detect the expression of eNOS and phosphorylated eNOS. In Ang II intervention group, NO contents were significantly lower than control group (P < 0.05). Through rhACE2 treatment, the NO contents in cell culture medium and the expression level of phosphorylated eNOS were significantly higher than in Ang II intervention group (P < 0.05), but eNOSmRNA and non-phosphorylated eNOS protein expression level showed no significant difference (P > 0.05). After HUVEC was intervened by PI3K/AKT pathway inhibitor LY294002, the expression level of phosphorylated eNOS was significantly lower than that in the rhACE2 30 min treatment group (P < 0.05). rhACE2 may reduce the activity of Ang II inhibited endothelial cell eNOS, which can be blocked by PI3K/AKT pathway inhibitor LY294002, suggesting PI3K/AKT signaling pathway plays an important role in rhACE2’s promotion of the activity of endothelial cell eNOS. PMID:25550859

  6. 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

  7. 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

  8. 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

  9. 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

  10. Gelsolin-mediated activation of PI3K/Akt pathway is crucial for hepatocyte growth factor-induced cell scattering in gastric carcinoma

    PubMed Central

    Huang, Baohua; Deng, Shuo; Loo, Ser Yue; Datta, Arpita; Yap, Yan Lin; Yan, Benedict; Ooi, Chia Huey; Dinh, Thuy Duong; Zhuo, Jingli; Tochhawng, Lalchhandami; Gopinadhan, Suma; Jegadeesan, Tamilarasi; Tan, Patrick; Salto-Tellez, Manuel; Yong, Wei Peng; Soong, Richie; Yeoh, Khay Guan; Goh, Yaw Chong; Lobie, Peter E.; Yang, Henry; Kumar, Alan Prem; Maciver, Sutherland K.; So, Jimmy B.Y.; Yap, Celestial T.

    2016-01-01

    In gastric cancer (GC), the main subtypes (diffuse and intestinal types) differ in pathological characteristics, with diffuse GC exhibiting early disseminative and invasive behaviour. A distinctive feature of diffuse GC is loss of intercellular adhesion. Although widely attributed to mutations in the CDH1 gene encoding E-cadherin, a significant percentage of diffuse GC do not harbor CDH1 mutations. We found that the expression of the actin-modulating cytoskeletal protein, gelsolin, is significantly higher in diffuse-type compared to intestinal-type GCs, using immunohistochemical and microarray analysis. Furthermore, in GCs with wild-type CDH1, gelsolin expression correlated inversely with CDH1 gene expression. Downregulating gelsolin using siRNA in GC cells enhanced intercellular adhesion and E-cadherin expression, and reduced invasive capacity. Interestingly, hepatocyte growth factor (HGF) induced increased gelsolin expression, and gelsolin was essential for HGF-medicated cell scattering and E-cadherin transcriptional repression through Snail, Twist and Zeb2. The HGF-dependent effect on E-cadherin was found to be mediated by interactions between gelsolin and PI3K-Akt signaling. This study reveals for the first time a function of gelsolin in the HGF/cMet oncogenic pathway, which leads to E-cadherin repression and cell scattering in gastric cancer. Our study highlights gelsolin as an important pro-disseminative factor contributing to the aggressive phenotype of diffuse GC. PMID:27058427

  11. Gelsolin-mediated activation of PI3K/Akt pathway is crucial for hepatocyte growth factor-induced cell scattering in gastric carcinoma.

    PubMed

    Huang, Baohua; Deng, Shuo; Loo, Ser Yue; Datta, Arpita; Yap, Yan Lin; Yan, Benedict; Ooi, Chia Huey; Dinh, Thuy Duong; Zhuo, Jingli; Tochhawng, Lalchhandami; Gopinadhan, Suma; Jegadeesan, Tamilarasi; Tan, Patrick; Salto-Tellez, Manuel; Yong, Wei Peng; Soong, Richie; Yeoh, Khay Guan; Goh, Yaw Chong; Lobie, Peter E; Yang, Henry; Kumar, Alan Prem; Maciver, Sutherland K; So, Jimmy B Y; Yap, Celestial T

    2016-05-01

    In gastric cancer (GC), the main subtypes (diffuse and intestinal types) differ in pathological characteristics, with diffuse GC exhibiting early disseminative and invasive behaviour. A distinctive feature of diffuse GC is loss of intercellular adhesion. Although widely attributed to mutations in the CDH1 gene encoding E-cadherin, a significant percentage of diffuse GC do not harbor CDH1 mutations. We found that the expression of the actin-modulating cytoskeletal protein, gelsolin, is significantly higher in diffuse-type compared to intestinal-type GCs, using immunohistochemical and microarray analysis. Furthermore, in GCs with wild-type CDH1, gelsolin expression correlated inversely with CDH1 gene expression. Downregulating gelsolin using siRNA in GC cells enhanced intercellular adhesion and E-cadherin expression, and reduced invasive capacity. Interestingly, hepatocyte growth factor (HGF) induced increased gelsolin expression, and gelsolin was essential for HGF-medicated cell scattering and E-cadherin transcriptional repression through Snail, Twist and Zeb2. The HGF-dependent effect on E-cadherin was found to be mediated by interactions between gelsolin and PI3K-Akt signaling. This study reveals for the first time a function of gelsolin in the HGF/cMet oncogenic pathway, which leads to E-cadherin repression and cell scattering in gastric cancer. Our study highlights gelsolin as an important pro-disseminative factor contributing to the aggressive phenotype of diffuse GC.

  12. 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

  13. c-Src activation promotes nasopharyngeal carcinoma metastasis by inducing the epithelial-mesenchymal transition via PI3K/Akt signaling pathway: a new and promising target for NPC.

    PubMed

    Ke, Liangru; Xiang, Yanqun; Guo, Xiang; Lu, Jinping; Xia, Weixiong; Yu, Yahui; Peng, Yongjian; Wang, Li; Wang, Gang; Ye, Yanfang; Yang, Jing; Liang, Hu; Kang, Tiebang; Lv, Xing

    2016-05-10

    Aberrant activation of cellular Src (c-Src), a non-receptor tyrosine kinase, could promote cancer progression through activating its downstream signaling pathways. However, the roles of c-Src and phosphorylated-Src (p-Src) in nasopharyngeal carcinoma (NPC) progression are rarely investigated. Herein, we have identified high c-Src concentrations in the serum of NPC patients with distant metastasis using high-throughput protein microarrays. Levels of c-Src in serum and p-Src in human primary NPC samples were unfavorable independent prognostic factors for cancer-specific survival, disease-free survival, and distant metastasis-free survival. Depletion or inactivation of c-Src in NPC cells using sgRNA with CRISPR/Cas9 system or PP2 decreased cell viability, colony formation, migration and invasion in vitro and metastasis in vivo. In contrast, these malignancies could be up-regulated by overexpressed c-Src in a NPC cell line with low-metastasis potential. Furthermore, p-Src was involved in promoting NPC cell metastasis by inducing the epithelial-mesenchymal transition (EMT) process via activating the PI3K/Akt pathway and cytoskeleton remodeling. The p-Src-induced EMT process could be retarded by PP2, which mediated by down-regulating the PI3K/Akt pathway. In conclusion, elevated levels of c-Src in serum and p-Src in primary NPC tissue correlated with poor outcomes of NPC patients. And aberrant activation of c-Src facilitated NPC cells with malignant potential, especially metastasis ability, which mediated by the PI3K/Akt pathway activation and sequentially induced the EMT process. These findings unveiled a promising approach for targeted therapy of advanced NPC. PMID:27078847

  14. c-Src activation promotes nasopharyngeal carcinoma metastasis by inducing the epithelial-mesenchymal transition via PI3K/Akt signaling pathway: a new and promising target for NPC

    PubMed Central

    Lu, Jinping; Xia, Weixiong; Yu, Yahui; Peng, Yongjian; Wang, Li; Wang, Gang; Ye, Yanfang; Yang, Jing; Liang, Hu; Kang, Tiebang; Lv, Xing

    2016-01-01

    Aberrant activation of cellular Src (c-Src), a non-receptor tyrosine kinase, could promote cancer progression through activating its downstream signaling pathways. However, the roles of c-Src and phosphorylated-Src (p-Src) in nasopharyngeal carcinoma (NPC) progression are rarely investigated. Herein, we have identified high c-Src concentrations in the serum of NPC patients with distant metastasis using high-throughput protein microarrays. Levels of c-Src in serum and p-Src in human primary NPC samples were unfavorable independent prognostic factors for cancer-specific survival, disease-free survival, and distant metastasis-free survival. Depletion or inactivation of c-Src in NPC cells using sgRNA with CRISPR/Cas9 system or PP2 decreased cell viability, colony formation, migration and invasion in vitro and metastasis in vivo. In contrast, these malignancies could be up-regulated by overexpressed c-Src in a NPC cell line with low-metastasis potential. Furthermore, p-Src was involved in promoting NPC cell metastasis by inducing the epithelial-mesenchymal transition (EMT) process via activating the PI3K/Akt pathway and cytoskeleton remodeling. The p-Src-induced EMT process could be retarded by PP2, which mediated by down-regulating the PI3K/Akt pathway. In conclusion, elevated levels of c-Src in serum and p-Src in primary NPC tissue correlated with poor outcomes of NPC patients. And aberrant activation of c-Src facilitated NPC cells with malignant potential, especially metastasis ability, which mediated by the PI3K/Akt pathway activation and sequentially induced the EMT process. These findings unveiled a promising approach for targeted therapy of advanced NPC. PMID:27078847

  15. Involvement of cyclin D1/CDK4 and pRb mediated by PI3K/AKT pathway activation in Pb{sup 2+}-induced neuronal death in cultured hippocampal neurons

    SciTech Connect

    Li Chenchen Xing Tairan Tang Mingliang Yong Wu Yan Dan Deng Hongmin Wang Huili Wang Ming Chen Jutao Ruan Diyun

    2008-06-15

    Lead (Pb) is widely recognized as a neurotoxicant. One of the suggested mechanisms of lead neurotoxicity is apoptotic cell death. And the mechanism by which Pb{sup 2+} causes neuronal death is not well understood. The present study sought to examine the obligate nature of cyclin D1/cyclin-dependent kinase 4 (CDK4), phosphorylation of its substrate retinoblastoma protein (pRb) and its select upstream signal phosphoinositide 3-kinase (PI3K)/AKT pathway in the death of primary cultured rat hippocampal neurons evoked by Pb{sup 2+}. Our data showed that lead treatment of primary hippocampal cultures results in dose-dependent cell death. Inhibition of CDK4 prevented Pb{sup 2+}-induced neuronal death significantly but was incomplete. In addition, we demonstrated that the levels of cyclin D1 and pRb/p107 were increased during Pb{sup 2+} treatment. These elevated expression persisted up to 48 h, returning to control levels after 72 h. We also presented pharmacological and morphological evidences that cyclin D1/CDK4 and pRb/p107 were required for such kind of neuronal death. Addition of the PI3K inhibitor LY294002 (30 {mu}M) or wortmannin (100 nM) significantly rescued the cultured hippocampal neurons from death caused by Pb{sup 2+}. And that Pb{sup 2+}-elicited phospho-AKT (Ser473) participated in the induction of cyclin D1 and partial pRb/p107 expression. These results provide evidences that cell cycle elements play a required role in the death of neurons evoked by Pb{sup 2+} and suggest that certain signaling elements upstream of cyclin D1/CDK4 are modified and/or required for this form of neuronal death.

  16. 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.

  17. Insulin induces a transcriptional activation of epiregulin, HB-EGF and amphiregulin, by a PI3K-dependent mechanism: Identification of a specific insulin-responsive promoter element

    SciTech Connect

    Ornskov, Dorthe; Nexo, Ebba; Sorensen, Boe S. . E-mail: boess@as.aaa.dk

    2007-03-23

    Previously we have shown that insulin-stimulation of RT4 bladder cancer cells leads to increased proliferation, which require HER1 activation, and is accompanied by increased mRNA expression of the EGF-ligands heparin-binding EGF-like growth factor (HB-EGF), amphiregulin (AR), and epiregulin (EPI) [D. Ornskov, E. Nexo, B.S. Sorensen, Insulin-induced proliferation of bladder cancer cells is mediated through activation of the epidermal growth factor system, FEBS J. 273 (2006) 5479-5489]. In the present paper, we have investigated the molecular mechanism leading to this insulin-induced expression. We monitored the decay of mRNA after inhibiting transcription with Actinomycin D and demonstrated that the insulin-mediated increase was not caused by enhanced mRNA stability. In untreated cells, HB-EGF mRNA was the least stable, whereas AR and EPI mRNA decayed with slower kinetics. However, promoter analysis of HB-EGF and EPI demonstrated that insulin stimulated transcription. Studies on the EPI promoter identified the insulin-responsive element to be located in the region -564 to -365 bp. This region contains potential binding sites for the transcription factors SP1, AP1, and NF-{kappa}B. Interestingly, all three transcription factors can be activated by PI3K. We demonstrate that the insulin-induced expression of HB-EGF, AR, and EPI mRNA is completely prevented by the specific PI3K inhibitor Wortmannin, suggesting an involvement of the PI3K.

  18. 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.

  19. Radiation persistently promoted oxidative stress, activated mTOR via PI3K/Akt, and downregulated autophagy pathway in mouse intestine.

    PubMed

    Datta, Kamal; Suman, Shubhankar; Fornace, Albert J

    2014-12-01

    While acute effects of toxic radiation doses on intestine are well established, we are yet to acquire a complete spectrum of sub-lethal radiation-induced chronic intestinal perturbations at the molecular level. We investigated persistent effects of a radiation dose (2 Gy) commonly used as a daily fraction in radiotherapy on oxidants and anti-oxidants, and autophagy pathways, which are interlinked processes affecting intestinal homeostasis. Six to eight weeks old C57BL/6J mice (n=10) were exposed to 2 Gy γ-ray. Mice were euthanized two or twelve months after radiation, intestine surgically removed, and flushed using sterile PBS. Parts of the intestine from jejunal-ilial region were fixed, frozen, or used for intestinal epithelial cell (IEC) isolation. While oxidant levels and mitochondrial status were assessed in isolated IEC, autophagy and oxidative stress related signaling pathways were probed in frozen and fixed samples using PCR-based expression arrays and immunoprobing. Radiation exposure caused significant alterations in the expression level of 26 autophagy and 17 oxidative stress related genes. Immunoblot results showed decreased Beclin1 and LC3-II and increased p62, PI3K/Akt, and mTOR. Flow cytometry data showed increased oxidant production and compromised mitochondrial integrity in irradiated samples. Immunoprobing of intestinal sections showed increased 8-oxo-dG and nuclear PCNA, and decreased autophagosome marker LC3-II in IEC after irradiation. We show that sub-lethal radiation could persistently downregulate anti-oxidants and autophagy signaling, and upregulate oxidant production and proliferative signaling. Radiation-induced promotion of oxidative stress and downregulation of autophagy could work in tandem to alter intestinal functions and have implications for post-radiation chronic gastrointestinal diseases.

  20. PACAP and VIP increase the expression of myelin-related proteins in rat schwannoma cells: involvement of PAC1/VPAC2 receptor-mediated activation of PI3K/Akt signaling pathways.

    PubMed

    Castorina, Alessandro; Scuderi, Soraya; D'Amico, Agata Grazia; Drago, Filippo; D'Agata, Velia

    2014-03-10

    PACAP and its cognate peptide VIP participate in various biological functions, including myelin maturation and synthesis. However, defining whether these peptides affect peripheral expression of myelin proteins still remains unanswered. To address this issue, we assessed whether PACAP or VIP contribute to regulate the expression of three myelin proteins (MAG, MBP and MPZ, respectively) using the rat schwannoma cell line (RT4-P6D2T), a well-established model to study myelin gene expression. In addition, we endeavored to partly unravel the underlying molecular mechanisms involved. Expression of myelin-specific proteins was assessed in cells grown either in normal serum (10% FBS) or serum starved and treated with or without 100 nM PACAP or VIP. Furthermore, through pharmacological approach using the PACAP/VIP receptor antagonist (PACAP6-38) or specific pathway (MAPK or PI3K) inhibitors we defined the relative contribution of receptors and/or signaling pathways on the expression of myelin proteins. Our data show that serum starvation (24h) significantly increased both MAG, MBP and MPZ expression. Concurrently, we observed increased expression of endogenous PACAP and related receptors. Treatment with PACAP or VIP further exacerbated starvation-induced expression of myelin markers, suggesting that serum withdrawal might sensitize cells to peptide activity. Stimulation with either peptides increased phosphorylation of Akt at Ser473 residue but had no effect on phosphorylated Erk-1/2. PACAP6-38 (10 μM) impeded starvation- or peptide-induced expression of myelin markers. Similar effects were obtained after pretreatment with the PI3K inhibitor (wortmannin, 10 μM) but not the MAPKK inhibitor (PD98059, 50 μM). Together, the present finding corroborate the hypothesis that PACAP and VIP might contribute to the myelinating process preferentially via the canonical PI3K/Akt signaling pathway, providing the basis for future studies on the role of these peptides in demyelinating

  1. Cytoplasmic localization of wild-type survivin is associated with constitutive activation of the PI3K/Akt signaling pathway and represents a favorable prognostic factor in patients with acute myeloid leukemia

    PubMed Central

    Serrano-López, Juana; Serrano, Josefina; Figueroa, Vianihuini; Torres-Gomez, Antonio; Tabares, Salvador; Casaño, Javier; Fernandez-Escalada, Noemi; Sánchez-Garcia, Joaquín

    2013-01-01

    Survivin is over-expressed in most hematologic malignancies but the prognostic significance of the subcompartmental distribution of wild-type or splicing variants in acute myeloid leukemia has not been addressed yet. Using western blotting, we assessed the expression of wild-type survivin and survivin splice variants 2B and Delta-Ex3 in nuclear and cytoplasmic protein extracts in samples taken from 105 patients at the time of their diagnosis of acute myeloid leukemia. Given that survivin is a downstream effector of the PI3K/Akt signaling pathway, survivin expression was also correlated with pSer473-Akt. Wild-type survivin and the 2B splice variant were positive in 76.3% and 78.0% of samples in the nucleus, cytoplasm or both, whereas the Delta-Ex3 isoform was only positive in the nucleus in 37.7% of samples. Cytoplasmic localization of wild-type survivin was significantly associated with the presence of high levels of pSer473-Akt (P<0.001). Inhibition of the PI3K/Akt pathway with wortmannin and Ly294002 caused a significant reduction in the expression of cytoplasmic wild-type survivin. The presence of cytoplasmic wild-type survivin and pSer473-Akt was associated with a lower fraction of quiescent leukemia stem cells (P=0.02). The presence of cytoplasmic wild-type survivin and pSer473-Akt were favorable independent prognostic factors. Moreover, the activation of the PI3K/Akt pathway with expression of cytoplasmic wild-type survivin identified a subgroup of acute myeloid leukemia patients with an excellent outcome (overall survival rate of 60.0±21.9% and relapse-free survival of 63.0±13.5%). Our findings suggest that cytoplasmic wild-type survivin is a critical downstream effector of the PI3K/Akt pathway leading to more chemosensitive cells and a more favorable outcome in acute myeloid leukemia. PMID:23812937

  2. [Role of phosphatidylinositol 3-kinase and myosin light chain kinase during the activation of thrombin receptors].

    PubMed

    Han, Yue; Gao, Hai-Li; Zhang, Wei; Bai, Xia; Dai, Lan; Sheng, Wen-Hong; Sun, Ai-Ning; Wu, De-Pei; Wang, Zhao-Yue; Ruan, Chang-Geng

    2009-06-01

    The objective of study was to compare the influences of wortmannin on platelet aggregation and platelet membrane surface glycoproteins GPIb expression after thrombin receptor activation, and to investigate the role of phosphatidylinositol 3-kinase (PI3-K) and myosin light chain kinase (MLCK) in the course of thrombin receptor activation. Peptide SFLLRN (PAR1-AP) and AYPGKF (PAR4-AP) were used for stimulating platelet, and the changes of platelet aggregation and GPIb were analyzed with 100 nmol/L wortmannin (inhibitor of PI3-K) and 10 micromol/L wortmannin (inhibitor of MLCK). The results indicated that the platelet activation was influenced by either concentration of wortmannin in response to PAR stimulation. Platelet aggregation was apparently inhibited by 10 micromol/L wortmannin through both PAR peptides, and was slightly inhibited by 100 nmol/L wortmannin only under PAR1-AP activation. In addition, GPIbalpha internalization was partly inhibited by 100 nmol/L wortmannin in response to PAR1 (p < 0.05 at 1, 2, 5 min) and PAR4 (p < 0.05 at 2, 5, 10 min) activation. Meanwhile, 10 micromol/L wortmannin induced little change for GPIbalpha centralisation in the course of PAR activation, with a delayed restoration of surface GPIbalpha observed under PAR1-AP activation, and no change of GPIbalpha redistribution existed under PAR4-AP activation. It is concluded that the different roles of PI3-K and MLCK exist in the course of thrombin receptor activation. PI3-K accelerates the short course of GPIb centralisation for two PAR signal pathways, while MLCK inhibits the restoration of GPIbalpha in PAR1 pathway. PMID:19549383

  3. Chronic intermittent fasting improves the survival following large myocardial ischemia by activation of BDNF/VEGF/PI3K signaling pathway.

    PubMed

    Katare, Rajesh G; Kakinuma, Yoshihiko; Arikawa, Mikihiko; Yamasaki, Fumiyasu; Sato, Takayuki

    2009-03-01

    Chronic heart failure (CHF) is the major cause of death in the developed countries. Calorie restriction is known to improve the recovery in these patients; however, the exact mechanism behind this protective effect is unknown. Here we demonstrate the activation of cell survival PI3kinase/Akt and VEGF pathway as the mechanism behind the protection induced by intermittent fasting in a rat model of established chronic myocardial ischemia (MI). Chronic MI was induced in rats by occlusion of the left coronary artery. Two weeks later, the rats were randomly assigned to a normal feeding group (MI-NF) and an alternate-day feeding group (MI-IF). After 6 weeks of observation, we evaluated the effect of intermittent fasting on cellular and ventricular remodeling and long-term survival after CHF. Compared with the normally fed group, intermittent fasting markedly improved the survival of rats with CHF (88.5% versus 23% survival, P<0.05). The heart weight body weight ratio was significantly less in the MI-IF group compared to the MI-NF group (3.4+/-0.17 versus 3.9+/-0.18, P<0.05). Isolated heart perfusion studies exhibited well preserved cardiac functions in the MI-IF group compared to the MI-NF group (P<0.05). Molecular studies revealed the upregulation of angiogenic factors such asHIF-1-alpha (3010+/-350% versus 650+/-151%), BDNF (523+/-32% versus 110+/-12%), and VEGF (450+/-21% versus 170+/-30%) in the fasted hearts. Immunohistochemical studies confirmed increased capillary density (P<0.001) in the border area of the ischemic myocardium and synthesis VEGF by cardiomyocytes. Moreover fasting also upregulated the expression of other anti-apoptotic factors such as Akt and Bcl-2 and reduced the TUNEL positive apoptotic nuclei in the border zone. Chronic intermittent fasting markedly improves the long-term survival after CHF by activation through its pro-angiogenic, anti-apoptotic and anti-remodeling effects.

  4. Wogonoside prevents colitis-associated colorectal carcinogenesis and colon cancer progression in inflammation-related microenvironment via inhibiting NF-κB activation through PI3K/Akt pathway

    PubMed Central

    Wang, Xiaoping; Zhao, Li; Li, Wenjun; Ding, Youxiang; Kong, Lingyi; Guo, Qinglong; Lu, Na

    2016-01-01

    The inflammatory microenvironment has been reported to be correlated with tumor initiation and malignant development. In the previous studies we have found that wogonoside exerts anti-neoplastic and anti-inflammatory activities. In this study, we aimed to further investigate the chemopreventive effects of wogonoside on colitis-associated cancer and delineated the potential mechanisms. In the azoxymethane initiated and dextran sulfate sodium (AOM/DSS) promoted colorectal carcinogenesis mouse model, wogonoside significantly reduced the disease severity, lowered tumor incidence and inhibited the development of colorectal adenomas. Moreover, wogonoside inhibited inflammatory cells infiltration and cancer cell proliferation at tumor site. Furthermore, wogonoside dramatically decreased the secretion and expression of IL-1β, IL-6 and TNF-α as well as the nuclear expression of NF-κB in adenomas and surrounding tissues. In vitro results showed that wogonoside suppressed the proliferation of human colon cancer cells in the inflammatory microenvironment. Mechanistically, we found that wogonoside inhibited NF-κB activation via PI3K/Akt pathway. In conclusion, our results demonstrated that wogonoside attenuated colitis-associated tumorigenesis in mice and inhibited the progression of human colon cancer in inflammation-related microenvironment via suppressing NF-κB activation by PI3K/Akt pathway, indicating that wogonoside could be a promising therapeutic agent for colorectal cancer. PMID:27102438

  5. The Asian-American variant of human papillomavirus type 16 exhibits higher activation of MAPK and PI3K/AKT signaling pathways, transformation, migration and invasion of primary human keratinocytes.

    PubMed

    Hochmann, Jimena; Sobrinho, João S; Villa, Luisa L; Sichero, Laura

    2016-05-01

    Asian-American (AA) HPV-16 variants are associated with higher risk of cancer. Abnormal activation of intracellular signaling play a critical role in cancer development and progression. Our aim was to elucidate mechanisms underlying the higher oncogenic potential attributed to AA variant. We evaluated activation of MAPK and PI3K/AKT pathways in primary human keratinocytes (PHKs) transduced with E6/E7 of three HPV-16 variants: E-P, AA, E-350G. Phenotypes examined included migration, anchorage independent growth and invasion. AA PHKs presented the highest levels of active proteins involved in all cascades analyzed: MAPK-ERK, MAPK-p38 and PI3K-AKT. AA PHKs were more efficient in promoting anchorage independent growth, and in stimulating cell migration and invasion. MEK1 inhibition decreased migration. The mesenchymal phenotype marker vimentin was increased in AA PHKs. Our results suggest that MEK1, ERK2, AKT2 hyperactivation influence cellular behavior by means of GSK-3b inactivation and EMT induction prompting AA immortalized PHKs to more efficiently surpass carcinogenesis steps.

  6. Rutin, A Natural Flavonoid Protects PC12 Cells Against Sodium Nitroprusside-Induced Neurotoxicity Through Activating PI3K/Akt/mTOR and ERK1/2 Pathway.

    PubMed

    Wang, Rikang; Sun, Yongbing; Huang, Hesong; Wang, Lan; Chen, Jinlong; Shen, Wei

    2015-09-01

    Free radicals induced neural damage is implicated in CNS diseases and rutin isolated form Lonicera japonica are reported to have neuroprotective activity. Previously, we confirmed that rutin exerted neuroprotective effect against sodium nitroprusside (SNP)-induced cell death in PC12 cells. However, the neuroprotective mechanism of rutin is still not fully uncovered. Here, we found that rutin significantly decreased SNP-induced reactive oxygen species in PC12 cells. Rutin reversed the declined GSH/GSSG ratio and mitochondrial membrane potential induced by SNP. Moreover, rutin activated both the protein Akt/mTOR and the extracellular signal-regulated kinase (ERK1/2) signaling pathways and the neuroprotective effects of rutin were blocked by either the specific PI3K inhibitor LY294002 or the MAPK pathway inhibitor PD98059. In summary, these results demonstrated that the neuroprotective effects of rutin might be through activating both the PI3K/Akt/mTOR and ERK1/2 signaling pathways. Our findings support that rutin may have therapeutic potential for the treatment of CNS diseases related to NO neurotoxicity. PMID:26255195

  7. Lithium potentiates GSK-3β activity by inhibiting phosphoinositide 3-kinase-mediated Akt phosphorylation

    SciTech Connect

    Tian, Nie; Kanno, Takeshi; Jin, Yu; Nishizaki, Tomoyuki

    2014-07-18

    Highlights: • Lithium suppresses Akt activity by reducing PI3K-mediated Akt phosphorylation. • Lithium enhances GSK-3β activity by reducing Akt-mediated GSK-3β phosphorylation. • Lithium suppresses GSK-3β activity through its direct inhibition. - Abstract: Accumulating evidence has pointed to the direct inhibitory action of lithium, an anti-depressant, on GSK-3β. The present study investigated further insight into lithium signaling pathways. In the cell-free assay Li{sub 2}CO{sub 3} significantly inhibited phosphoinositide 3-kinase (PI3K)-mediated phosphorylation of Akt1 at Ser473, but Li{sub 2}CO{sub 3} did not affect PI3K-mediated PI(3,4,5)P{sub 3} production and 3-phosphoinositide-dependent protein kinase 1 (PDK1)-mediated phosphorylation of Akt1 at Thr308. This indicates that lithium could enhance GSK-3β activity by suppressing Akt-mediated Ser9 phosphorylation of GSK-3β in association with inhibition of PI3K-mediated Akt activation. There was no direct effect of Li{sub 2}CO{sub 3} on Akt1-induced phosphorylation of GSK-3β at Ser9, but otherwise Li{sub 2}CO{sub 3} significantly reduced GSK-3β-mediated phosphorylation of β-catenin at Ser33/37 and Thr41. This indicates that lithium directly inhibits GSK-3β in an Akt-independent manner. In rat hippocampal slices Li{sub 2}CO{sub 3} significantly inhibited phosphorylation of Akt1/2 at Ser473/474, GSK-3β at Ser9, and β-catenin at Ser33/37 and Thr41. Taken together, these results indicate that lithium exerts its potentiating and inhibiting bidirectional actions on GSK-3β activity.

  8. Activation of the PI3K/Akt/mTOR/p70S6K Pathway is Involved in S100A4-induced Viability and Migration in Colorectal Cancer Cells

    PubMed Central

    Wang, Haiyan; Duan, Liang; Zou, Zhengyu; Li, Huan; Yuan, Shimei; Chen, Xian; Zhang, Yunyuan; Li, Xueru; Sun, Hui; Zha, He; Zhang, Yan; Zhou, Lan

    2014-01-01

    The S100 protein family member S100A4 regulates various cellular functions. Previous studies have shown that elevated expression of S100A4 is associated with progression and metastasis of colorectal cancer (CRC). However, little is known about whether and how S100A4 contributes to CRC development. In our present study, the elevated expression of S100A4 in CRC tissues compared to matched adjacent normal tissues was confirmed by immunohistochemistry, semi-quantitative RT-PCR and Western blot. Adenovirus-mediated S100A4 overexpression obviously enhanced viability and migration of CRC cells, which was detected by MTT assay and transwell assay, respectively. Additionally, S100A4 overexpression increased the phosphorylation levels of Akt, mTOR and p70S6K. These effects of S100A4 were abolished by treatment with either the specific PI3K/Akt inhibitor LY294002, or the specific mTOR/p70S6K inhibitor rapamycin. Furthermore, overexpression of S100A4 resulted in upregulation of VEGF and downregulation of E-cadherin, which were strongly reversed by either LY294002 or rapamycin. Altogether, our results demonstrate that activation of the PI3K/Akt/mTOR/p70S6K signaling pathway is involved in S100A4-induced viability, migration, upregulation of VEGF and downregulation of E-cadherin in CRC cells. PMID:24936148

  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. Anti-neoplastic activity of low-dose endothelial-monocyte activating polypeptide-II results from defective autophagy and G2/M arrest mediated by PI3K/Akt/FoxO1 axis in human glioblastoma stem cells.

    PubMed

    Liu, Jing; Liu, Libo; Xue, Yixue; Meng, Fanjie; Li, Shuai; Wang, Ping; Liu, Yunhui

    2014-06-15

    Glioblastoma multiforme (GBM) is a life-threatening brain tumor with fatal recurrence, for which glioblastoma stem cells (GSCs) are held responsible. Though endothelial-monocyte activating polypeptide-II (EMAP-II) has been confirmed as a possible antitumor agent that can induce apoptosis of endothelial cells and inhibit tumor angiogenesis, the direct cytotoxicity by EMAP-II on tumor cells and its underlying mechanism are largely unknown. In the present study, it was demonstrated that low-dose (0.05 nM) EMAP-II reduces cell viability and mitochondrial membrane potential in vitro. Likewise, EMAP-II suppressed tumor growth in GSC-xenografted mice. Though no apoptosis was detected, all these antitumor effects were attenuated when GSCs were pretreated with 3-methyladenine (3-MA). Analysis of EMAP-II-treated GSCs exhibited the morphological and biochemical changes typical of autophagy, which was further shown to be defective. Moreover, EMAP-II was found to suppress tumor growth by inducing G2/M arrest in GSCs. Our data further showed that EMAP-II inhibited PI3K/Akt activation with concomitant induction of FoxO1 activation. FoxO1 knockdown significantly attenuated the induction of autophagy and G2/M arrest. Excessive accumulation of lipid droplets was intriguingly detected by transmission electron microscope, which was accompanied by autophagosomes. Further investigation indicated that the transcriptional regulation of Atg2B by FoxO1 was responsible for the induction of autophagy and formation of lipid droplets. These results suggest that EMAP-II is an effective anticancer agent for glioblastoma therapy, which can induce direct growth suppression in GSCs through defective autophagy and G2/M arrest mediated by the PI3K/Akt/FoxO1 axis.

  11. 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

  12. Gallic acid attenuates high-fat diet fed-streptozotocin-induced insulin resistance via partial agonism of PPARγ in experimental type 2 diabetic rats and enhances glucose uptake through translocation and activation of GLUT4 in PI3K/p-Akt signaling pathway.

    PubMed

    Gandhi, Gopalsamy Rajiv; Jothi, Gnanasekaran; Antony, Poovathumkal James; Balakrishna, Kedike; Paulraj, Michael Gabriel; Ignacimuthu, Savarimuthu; Stalin, Antony; Al-Dhabi, Naif Abdullah

    2014-12-15

    In this study, the therapeutic efficacy of gallic acid from Cyamopsis tetragonoloba (L.) Taub. (Fabaceae) beans was examined against high-fat diet fed-streptozotocin-induced experimental type 2 diabetic rats. Molecular-dockings were done to determine the putative binding modes of gallic acid into the active sites of key insulin-signaling markers. Gallic acid (20 mg/kg) given to high-fat diet fed-streptozotocin-induced rats lowered body weight gain, fasting blood glucose and plasma insulin in diabetic rats. It further restored the alterations of biochemical parameters to near normal levels in diabetic treated rats along with cytoprotective action on pancreatic β-cell. Histology of liver and adipose tissues supported the biochemical findings. Gallic acid significantly enhanced the level of peroxisome proliferator-activated receptor γ (PPARγ) expression in the adipose tissue of treated rat compared to untreated diabetic rat; it also slightly activated PPARγ expressions in the liver and skeletal muscle. Consequently, it improved insulin-dependent glucose transport in adipose tissue through translocation and activation of glucose transporter protein 4 (GLUT4) in phosphatidylinositol 3-kinase (PI3K)/phosphorylated protein kinase B (p-Akt) dependent pathway. Gallic acid docked with PPARγ; it exhibited promising interactions with the GLUT4, glucose transporter protein 1 (GLUT1), PI3K and p-Akt. These findings provided evidence to show that gallic acid could improve adipose tissue insulin sensitivity, modulate adipogenesis, increase adipose glucose uptake and protect β-cells from impairment. Hence it can be used in the management of obesity-associated type 2 diabetes mellitus.

  13. 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

  14. 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.

  15. 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

  16. 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

  17. 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.

  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. 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

  20. 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

  1. 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

  2. Uncarboxylated osteocalcin inhibits high glucose-induced ROS production and stimulates osteoblastic differentiation by preventing the activation of PI3K/Akt in MC3T3-E1 cells.

    PubMed

    Liu, Jingli; Yang, Jianhong

    2016-01-01

    Uncarboxylated osteocalcin, an osteoblast-derived protein, plays an important role in the regulation of glucose metabolism. It has previously been demonstrated that high glucose levels inhibit osteoblast proliferation and differentiation. However, the mechanisms through which uncarboxylated osteocalcin regulates osteoblast proliferation and differentiation under high glucose conditions remain unclear. Thus, in the present study, we aimed to examine the effects of uncarboxylated osteocalcin on the proliferation and differentiation of MC3T3-E1 cells under high glucose conditions. We demonstrated that high glucose levels induced the production of reactive oxygen species (ROS) in MC3T3-E1 cells, and this production was inhibited by treatment with uncarboxylated osteocalcin and N-acetyl-L-cysteine (NAC), a ROS scavenger. In addition, we found that uncarboxylated osteocalcin reduced high glucose‑induced oxidative stress and increased the mRNA expression of the osteogenic markers, runt-related transcription factor 2 (Runx2), osterix and osteocalcin, as well as the formation of mineralized nodules; it also inhibited adipogenic differentiation, as shown by a decrease in the mRNA expression of the adipogenic markers, peroxisome proliferator‑activated receptor γ (PPARγ), adipocyte fatty acid-binding protein (adipocyte protein 2; aP2) and fatty acid synthase (FAS), and reduced lipid drop accumulation. Furthermore, we found that uncarboxylated osteocalcin inhibited PI3K/Akt signaling which was induced by ROS and facilitated the osteogenic differentiation of MC3T3-E1 cells under high glucose conditions. Taken together and to the best of ou knowledge, our results demonstrate for the first time that uncarboxylated osteocalcin inhibits high glucose-induced ROS production and stimulates osteoblastic differentiation by inhibiting the activation of PI3K/Akt in MC3T3-E1 cells. Therefore, we suggest that uncarboxylated osteocalcin may be a potential therapeutic agent for diabetes

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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.

  10. Phosphatidylinositol 3-Kinase Couples Localised Calcium Influx to Activation of Akt in Central Nerve Terminals.

    PubMed

    Nicholson-Fish, Jessica C; Cousin, Michael A; Smillie, Karen J

    2016-03-01

    The efficient retrieval of synaptic vesicle membrane and cargo in central nerve terminals is dependent on the efficient recruitment of a series of endocytosis modes by different patterns of neuronal activity. During intense neuronal activity the dominant endocytosis mode is activity-dependent endocytosis (ADBE). Triggering of ADBE is linked to calcineurin-mediated dynamin I dephosphorylation since the same stimulation intensities trigger both. Dynamin I dephosphorylation is maximised by a simultaneous inhibition of its kinase glycogen synthase kinase 3 (GSK3) by the protein kinase Akt, however it is unknown how increased neuronal activity is transduced into Akt activation. To address this question we determined how the activity-dependent increases in intracellular free calcium ([Ca(2+)]i) control activation of Akt. This was achieved using either trains of high frequency action potentials to evoke localised [Ca(2+)]i increases at active zones, or a calcium ionophore to raise [Ca(2+)]i uniformly across the nerve terminal. Through the use of either non-specific calcium channel antagonists or intracellular calcium chelators we found that Akt phosphorylation (and subsequent GSK3 phosphorylation) was dependent on localised [Ca(2+)]i increases at the active zone. In an attempt to determine mechanism, we antagonised either phosphatidylinositol 3-kinase (PI3K) or calmodulin. Activity-dependent phosphorylation of both Akt and GSK3 was arrested on inhibition of PI3K, but not calmodulin. Thus localised calcium influx in central nerve terminals activates PI3K via an unknown calcium sensor to trigger the activity-dependent phosphorylation of Akt and GSK3.

  11. 13-acetoxysarcocrassolide induces apoptosis on human gastric carcinoma cells through mitochondria-related apoptotic pathways: p38/JNK activation and PI3K/AKT suppression.

    PubMed

    Su, Ching-Chyuan; Chen, Jeff Yi-Fu; Din, Zhong-Hao; Su, Jui-Hsin; Yang, Zih-Yan; Chen, Yi-Jen; Wang, Robert Y L; Wu, Yu-Jen

    2014-10-01

    13-acetoxysarcocrassolide (13-AC), an active compound isolated from cultured Formosa soft coral Sarcophyton crassocaule, was found to possess anti-proliferative and apoptosis-inducing activities against AGS (human gastric adenocarcinoma cells) gastric carcinoma cells. The anti-tumor effects of 13-AC were determined by MTT assay, colony formation assessment, cell wound-healing assay, TUNEL/4,6-Diamidino-2-phenylindole (DAPI) staining, Annexin V-fluorescein isothiocyanate/propidium iodide (PI) staining and flow cytometry. 13-AC inhibited the growth and migration of gastric carcinoma cells in a dose-dependent manner and induced both early and late apoptosis as assessed by flow cytometer analysis. 13-AC-induced apoptosis was confirmed through observation of a change in ΔΨm, up-regulated expression levels of Bax and Bad proteins, down-regulated expression levels of Bcl-2, Bcl-xl and Mcl-1 proteins, and the activation of caspase-3, caspase-9, p38 and JNK. Furthermore, inhibition of p38 and JNK activity by pretreatment with SB03580 (a p38-specific inhibitor) and SP600125 (a JNK-specific inhibitor) led to rescue of the cell cytotoxicity of 13-AC-treated AGS cells, indicating that the p38 and the JNK pathways are also involved in the 13-AC-induced cell apoptosis. Together, these results suggest that 13-AC induces cell apoptosis against gastric cancer cells through triggering of the mitochondrial-dependent apoptotic pathway as well as activation of the p38 and JNK pathways. PMID:25342459

  12. Control of Cardiac Repolarization by Phosphoinositide 3-kinase Signaling to Ion Channels

    PubMed Central

    Ballou, Lisa M.; Lin, Richard Z.; Cohen, Ira S.

    2014-01-01

    Upregulation of phosphoinositide 3-kinase (PI3K) signaling is a common alteration in human cancer, and numerous drugs that target this pathway have been developed for cancer treatment. However, recent studies have implicated inhibition of the PI3K signaling pathway as the cause of a drug-induced long QT syndrome in which alterations in several ion currents contribute to arrhythmogenic drug activity. Surprisingly, some drugs that were thought to induce long QT syndrome by direct block of the rapid delayed rectifier (IKr) also appear to inhibit PI3K signaling, an effect that may contribute to their arrhythmogenicity. The importance of PI3K in regulating cardiac repolarization is underscored by evidence that QT interval prolongation in diabetes also may result from changes in multiple currents due to decreased insulin activation of PI3K in the heart. How PI3K signaling regulates ion channels to control the cardiac action potential is poorly understood. Hence, this review summarizes what is known about the impact of PI3K and its downstream effectors including Akt on sodium, potassium and calcium currents in cardiac myocytes. We also refer to some studies in non-cardiac cells that provide insight into potential mechanisms of ion channel regulation by this signaling pathway in the heart. Drug development and safety could be improved with a better understanding of the mechanisms by which PI3K regulates cardiac ion channels and the extent to which PI3K inhibition contributes to arrhythmogenic susceptibility. PMID:25552692

  13. PI3K/Akt-independent NOS/HO activation accounts for the facilitatory effect of nicotine on acetylcholine renal vasodilations: modulation by ovarian hormones.

    PubMed

    Gohar, Eman Y; El-gowilly, Sahar M; El-Gowelli, Hanan M; El-Demellawy, Maha A; El-Mas, Mahmoud M

    2014-01-01

    We investigated the effect of chronic nicotine on cholinergically-mediated renal vasodilations in female rats and its modulation by the nitric oxide synthase (NOS)/heme oxygenase (HO) pathways. Dose-vasodilatory response curves of acetylcholine (0.01-2.43 nmol) were established in isolated phenylephrine-preconstricted perfused kidneys obtained from rats treated with or without nicotine (0.5-4.0 mg/kg/day, 2 weeks). Acetylcholine vasodilations were potentiated by low nicotine doses (0.5 and 1 mg/kg/day) in contrast to no effect for higher doses (2 and 4 mg/kg/day). The facilitatory effect of nicotine was acetylcholine specific because it was not observed with other vasodilators such as 5'-N-ethylcarboxamidoadenosine (NECA, adenosine receptor agonist) or papaverine. Increases in NOS and HO-1 activities appear to mediate the nicotine-evoked enhancement of acetylcholine vasodilation because the latter was compromised after pharmacologic inhibition of NOS (L-NAME) or HO-1 (zinc protoporphyrin, ZnPP). The renal protein expression of phosphorylated Akt was not affected by nicotine. We also show that the presence of the two ovarian hormones is necessary for the nicotine augmentation of acetylcholine vasodilations to manifest because nicotine facilitation was lost in kidneys of ovariectomized (OVX) and restored after combined, but not individual, supplementation with medroxyprogesterone acetate (MPA) and estrogen (E2). Together, the data suggests that chronic nicotine potentiates acetylcholine renal vasodilation in female rats via, at least partly, Akt-independent HO-1 upregulation. The facilitatory effect of nicotine is dose dependent and requires the presence of the two ovarian hormones.

  14. Propofol mediates signal transducer and activator of transcription 3 activation and crosstalk with phosphoinositide 3-kinase/AKT

    PubMed Central

    Shravah, Jayant; Wang, Baohua; Pavlovic, Marijana; Kumar, Ujendra; Chen, David DY; Luo, Honglin; Ansley, David M

    2014-01-01

    We previously demonstrated that propofol, an intravenous anesthetic with anti-oxidative properties, activated the phosphoinositide 3-kinase (PI3K)/AKT pathway to increase the expression of B cell lymphoma (Bcl)-2 and, therefore the anti-apoptotic potential on cardiomyocytes. Here, we wanted to determine if propofol can also activate the Janus kinase (JAK) 2/signal transducer and activator of transcription (STAT) 3 pathway, another branch of cardioprotective signaling. The cellular response of nuclear factor kappa B (NFκB) and STAT3 was also evaluated. Cardiac H9c2 cells were treated by propofol alone or in combination with pretreatment by inhibitors for JAK2/STAT3 or PI3K/AKT pathway. STAT3 and AKT phosphorylation, and STAT3 translocation were measured by western blotting and immunofluorescence staining, respectively. Propofol treatment significantly increased STAT3 phosphorylation at both tyrosine 705 and serine 727 residues. Sustained early phosphorylation of STAT3 was observed with 25~75 μM propofol at 10 and 30 min. Nuclear translocation of STAT3 was seen at 4 h after treatment with 50 μM propofol. In cultured H9c2 cells, we further demonstrated that propofol-induced STAT3 phosphorylation was reduced by pretreatment with PI3K/AKT pathway inhibitors wortmannin or API-2. Conversely, pretreatment with JAK2/STAT3 pathway inhibitor AG490 or stattic inhibited propofol-induced AKT phosphorylation. In addition, propofol induced NFκB p65 subunit perinuclear translocation. Inhibition or knockdown of STAT3 was associated with increased levels of the NFκB p65 subunit. Our results suggest that propofol induces an adaptive response by dual activation and crosstalk of cytoprotective PI3K/AKT and JAK2/STAT3 pathways. Rationale to apply propofol clinically as a preemptive cardioprotectant during cardiac surgery is supported by our findings. PMID:25105067

  15. 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.

  16. 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

  17. The Anti-Tumor Activity of Succinyl Macrolactin A Is Mediated through the β-Catenin Destruction Complex via the Suppression of Tankyrase and PI3K/Akt

    PubMed Central

    Kim, Seung Joo; Banskota, Suhrid; Shah, Sajita; Kim, Jung-Ae

    2015-01-01

    Accumulated gene mutations in cancer suggest that multi-targeted suppression of affected signaling networks is a promising strategy for cancer treatment. In the present study, we report that 7-O-succinyl macrolactin A (SMA) suppresses tumor growth by stabilizing the β-catenin destruction complex, which was achieved through inhibition of regulatory components associated with the complex. SMA significantly reduced the activities of PI3K/Akt, which corresponded with a decrease in GSK3β phosphorylation, an increase in β-catenin phosphorylation, and a reduction in nuclear β-catenin content in HT29 human colon cancer cells. At the same time, the activity of tankyrase, which inhibits the β-catenin destruction complex by destabilizing the axin level, was suppressed by SMA. Despite the low potency of SMA against tankyrase activity (IC50 of 50.1 μM and 15.5 μM for tankyrase 1 and 2, respectively) compared to XAV939 (IC50 of 11 nM for tankyrase 1), a selective and potent tankyrase inhibitor, SMA had strong inhibitory effects on β-catenin-dependent TCF/LEF1 transcriptional activity (IC50 of 39.8 nM), which were similar to that of XAV939 (IC50 of 28.1 nM). In addition to suppressing the colony forming ability of colon cancer cells in vitro, SMA significantly inhibited tumor growth in CT26 syngenic and HT29 xenograft mouse tumor models. Furthermore, treating mice with SMA in combination with 5-FU in a colon cancer xenograft model or with cisplatin in an A549 lung cancer xenograft model resulted in greater anti-tumor activity than did treatment with the drugs alone. In the xenograft tumor tissues, SMA dose-dependently inhibited nuclear β-catenin along with reductions in GSK3β phosphorylation and increases in axin levels. These results suggest that SMA is a possible candidate as an effective anti-cancer agent alone or in combination with cytotoxic chemotherapeutic drugs, such as 5-FU and cisplatin, and that the mode of action for SMA involves stabilization of the

  18. 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

  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. Long-Term Administration of Dehydroepiandrosterone Accelerates Glucose Catabolism via Activation of PI3K/Akt-PFK-2 Signaling Pathway in Rats Fed a High-Fat Diet.

    PubMed

    Kang, Jian; Ge, Chongyang; Yu, Lei; Li, Longlong; Ma, Haitian

    2016-01-01

    Dehydroepiandrosterone (DHEA) has a fat-reducing effect, while little information is available on whether DHEA regulates glucose metabolism, which would in turn affect fat deposition. To investigate the effects of DHEA on glucose metabolism, rats were administered a high-fat diet containing either 0 (HCG), 25 (HLG), 50 (HMG), or 100 (HHG) mg·kg-1 DHEA per day via gavage for 8 weeks. Results showed that long-term administration of DHEA inhibited body weight gain in rats on a high-fat diet. No statistical differences in serum glucose levels were observed, whereas hepatic glycogen content in HMG and HHG groups and muscle glycogen content in HLG and HMG groups were higher than those in HCG group. Glucokinase, malate dehydrogenase and phosphofructokinase-2 activities in HMG and HHG groups, pyruvate kinase and succinate dehydrogenase activities in HMG group, and pyruvate dehydrogenase activity in all DHEA treatment groups were increased compared with those in HCG group. Phosphoenolpyruvate carboxykinase and glycogen phosphorylase mRNA levels were decreased in HMG and HHG groups, whereas glycogen synthase-2 mRNA level was increased in HMG group compared with those in HCG. The abundance of Glut2 mRNA in HMG and HHG groups and Glut4 mRNA in HMG group was higher than that in HCG group. DHEA treatment increased serum leptin content in HMG and HHG groups compared with that in HCG group. Serum insulin content and insulin receptor mRNA level in HMG group and insulin receptor substrate-2 mRNA level in HMG and HHG group were increased compared with those in HCG group. Furthermore, Pi3k mRNA level in HMG and Akt mRNA level in HMG and HHG groups were significantly increased than those in HCG group. These data showed that DHEA treatment could enhance glycogen storage and accelerate glucose catabolism in rats fed a high-fat diet, and this effect may be associated with the activation of PI3K/Akt-PFK-2 signaling pathway. PMID:27410429

  1. Long-Term Administration of Dehydroepiandrosterone Accelerates Glucose Catabolism via Activation of PI3K/Akt-PFK-2 Signaling Pathway in Rats Fed a High-Fat Diet

    PubMed Central

    Kang, Jian; Ge, Chongyang; Yu, Lei; Li, Longlong; Ma, Haitian

    2016-01-01

    Dehydroepiandrosterone (DHEA) has a fat-reducing effect, while little information is available on whether DHEA regulates glucose metabolism, which would in turn affect fat deposition. To investigate the effects of DHEA on glucose metabolism, rats were administered a high-fat diet containing either 0 (HCG), 25 (HLG), 50 (HMG), or 100 (HHG) mg·kg-1 DHEA per day via gavage for 8 weeks. Results showed that long-term administration of DHEA inhibited body weight gain in rats on a high-fat diet. No statistical differences in serum glucose levels were observed, whereas hepatic glycogen content in HMG and HHG groups and muscle glycogen content in HLG and HMG groups were higher than those in HCG group. Glucokinase, malate dehydrogenase and phosphofructokinase-2 activities in HMG and HHG groups, pyruvate kinase and succinate dehydrogenase activities in HMG group, and pyruvate dehydrogenase activity in all DHEA treatment groups were increased compared with those in HCG group. Phosphoenolpyruvate carboxykinase and glycogen phosphorylase mRNA levels were decreased in HMG and HHG groups, whereas glycogen synthase-2 mRNA level was increased in HMG group compared with those in HCG. The abundance of Glut2 mRNA in HMG and HHG groups and Glut4 mRNA in HMG group was higher than that in HCG group. DHEA treatment increased serum leptin content in HMG and HHG groups compared with that in HCG group. Serum insulin content and insulin receptor mRNA level in HMG group and insulin receptor substrate-2 mRNA level in HMG and HHG group were increased compared with those in HCG group. Furthermore, Pi3k mRNA level in HMG and Akt mRNA level in HMG and HHG groups were significantly increased than those in HCG group. These data showed that DHEA treatment could enhance glycogen storage and accelerate glucose catabolism in rats fed a high-fat diet, and this effect may be associated with the activation of PI3K/Akt-PFK-2 signaling pathway. PMID:27410429

  2. Choline phosphate potentiates sphingosine-1-phosphate-induced Raf-1 kinase activation dependent of Ras--phosphatidylinositol-3-kinase pathway.

    PubMed

    Lee, Michael; Han, Sang Seop

    2002-04-01

    In NIH3T3 cells, sphingosine-1-phosphate (S1P) caused a significant increase of Raf-1 kinase activity as early as 2 min. Interestingly, choline phosphate (ChoP) produced synergistic increase of S1P-stimulated Raf-1 kinase activation in the presence of ATP while showing additive effect in the absence of ATP. However, Raf-1 kinase activation induced by S1P decreased in the presence of ATP when applied alone. The overexpression of N-terminal fragment of Raf-1 (RfI) to inhibit Raf--Ras interaction caused the inhibition of S1P-induced Raf-1 kinase activation. Also, wortmannin, phosphatidylinositol-3-kinase (PI3K) inhibitor, exhibited inhibitory effects on S1P-induced activation of Raf-1 kinase. In addition, we demonstrated that the chemical antioxidant, N-acetylcysteine attenuated Raf-1 activation induced by S1P, suggesting that H(2)O(2) may be required for the signalling pathway leading to Raf-1 activation. This H(2)O(2)-induced Raf-1 kinase activation was also blocked by inhibition of Ras--PI3K signalling pathway using alpha-hydroxyfarnesylphosphonic acid and wortmannin. Taken together, these results indicate that S1P-induced Raf-1 kinase activation is mediated by H(2)O(2) stimulation of Ras--PI3K pathway, and is enhanced by ChoP in the presence of ATP.

  3. 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.

  4. 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.

  5. 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

  6. 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

  7. 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.

  8. 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

  9. 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

  10. 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.

  11. 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

  12. 11-epi-Sinulariolide Acetate Reduces Cell Migration and Invasion of Human Hepatocellular Carcinoma by Reducing the Activation of ERK1/2, p38MAPK and FAK/PI3K/AKT/mTOR Signaling Pathways

    PubMed Central

    Lin, Jen-Jie; Su, Jui-Hsin; Tsai, Chi-Chu; Chen, Yi-Jen; Liao, Ming-Hui; Wu, Yu-Jen

    2014-01-01

    Cancer metastasis is one of the major causes of death in cancer. An active compound, 11-epi-sinulariolide acetate (11-epi-SA), isolated from the cultured soft coral Sinularia flexibilis has been examined for potential anti-cell migration and invasion effects on hepatocellular carcinoma cells (HCC). However, the molecular mechanism of anti-migration and invasion by 11-epi-SA on HCC, along with their corresponding effects, remain poorly understood. In this study, we investigated anti-migration and invasion effects and the underlying mechanism of 11-epi-SA in HA22T cells, and discovered by trans-well migration and invasion assays that 11-epi-SA provided a concentration-dependent inhibitory effect on the migration of human HCC HA22T cells. After treatment with 11-epi-SA for 24 h, there were suppressed protein levels of matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9) and urokinase-type plasminogen activator (uPA) in HA22T cells. Meanwhile, the expression of tissue inhibitor of metalloproteinase-1 (TIMP-1) and metalloproteinase-2 (TIMP-2) were increased in a concentration-dependent manner. Further investigation revealed that 11-epi-SA suppressed the phosphorylation of ERK1/2 and p38MAPK. The 11-epi-SA also suppressed the expression of the phosphorylation of FAK/PI3K/AKT/mTOR pathways. PMID:25222667

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. 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

  18. 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.

  19. Cell autonomous phosphoinositide 3-kinase activation in oocytes disrupts normal ovarian function through promoting survival and overgrowth of ovarian follicles.

    PubMed

    Kim, So-Youn; Ebbert, Katherine; Cordeiro, Marilia H; Romero, Megan; Zhu, Jie; Serna, Vanida Ann; Whelan, Kelly A; Woodruff, Teresa K; Kurita, Takeshi

    2015-04-01

    In this study, we explored the effects of oocytic phosphoinositide 3-kinase (PI3K) activation on folliculogensis by generating transgenic mice, in which the oocyte-specific Cre-recombinase induces the expression of constitutively active mutant PI3K during the formation of primordial follicles. The ovaries of neonatal transgenic (Cre+) mice showed significantly reduced apoptosis in follicles, which resulted in an excess number of follicles per ovary. Thus, the elevation of phosphatidylinositol (3,4,5)-trisphosphate levels within oocytes promotes the survival of follicles during neonatal development. Despite the increase in AKT phosphorylation, primordial follicles in neonatal Cre+ mice remained dormant demonstrating a nuclear accumulation of phosphatase and tensin homolog deleted on chromosome 10 (PTEN). These primordial follicles containing a high level of nuclear PTEN persisted in postpubertal females, suggesting that PTEN is the dominant factor in the maintenance of female reproductive lifespan through the regulation of primordial follicle recruitment. Although the oocytic PI3K activity and PTEN levels were elevated, the activation of primordial follicles and the subsequent accumulation of antral follicles with developmentally competent oocytes progressed normally in prepubertal Cre+ mice. However, mature Cre+ female mice were anovulatory. Because postnatal day 50 Cre+ mice released cumulus-oocyte complexes with developmentally competent oocytes in response to super-ovulation treatment, the anovulatory phenotype was not due to follicular defects but rather endocrine abnormalities, which were likely caused by the excess number of overgrown follicles. Our current study has elucidated the critical role of oocytic PI3K activity in follicular function, as well as the presence of a PTEN-mediated mechanism in the prevention of immature follicle activation.

  20. Cell Autonomous Phosphoinositide 3-Kinase Activation in Oocytes Disrupts Normal Ovarian Function Through Promoting Survival and Overgrowth of Ovarian Follicles

    PubMed Central

    Ebbert, Katherine; Cordeiro, Marilia H.; Romero, Megan; Zhu, Jie; Serna, Vanida Ann; Whelan, Kelly A.; Woodruff, Teresa K.

    2015-01-01

    In this study, we explored the effects of oocytic phosphoinositide 3-kinase (PI3K) activation on folliculogensis by generating transgenic mice, in which the oocyte-specific Cre-recombinase induces the expression of constitutively active mutant PI3K during the formation of primordial follicles. The ovaries of neonatal transgenic (Cre+) mice showed significantly reduced apoptosis in follicles, which resulted in an excess number of follicles per ovary. Thus, the elevation of phosphatidylinositol (3,4,5)-trisphosphate levels within oocytes promotes the survival of follicles during neonatal development. Despite the increase in AKT phosphorylation, primordial follicles in neonatal Cre+ mice remained dormant demonstrating a nuclear accumulation of phosphatase and tensin homolog deleted on chromosome 10 (PTEN). These primordial follicles containing a high level of nuclear PTEN persisted in postpubertal females, suggesting that PTEN is the dominant factor in the maintenance of female reproductive lifespan through the regulation of primordial follicle recruitment. Although the oocytic PI3K activity and PTEN levels were elevated, the activation of primordial follicles and the subsequent accumulation of antral follicles with developmentally competent oocytes progressed normally in prepubertal Cre+ mice. However, mature Cre+ female mice were anovulatory. Because postnatal day 50 Cre+ mice released cumulus-oocyte complexes with developmentally competent oocytes in response to super-ovulation treatment, the anovulatory phenotype was not due to follicular defects but rather endocrine abnormalities, which were likely caused by the excess number of overgrown follicles. Our current study has elucidated the critical role of oocytic PI3K activity in follicular function, as well as the presence of a PTEN-mediated mechanism in the prevention of immature follicle activation. PMID:25594701

  1. 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

  2. Cardioprotective Stimuli Mediate Phosphoinositide 3-Kinase and Phosphoinositide Dependent Kinase 1 Nuclear Accumulation in Cardiomyocytes

    PubMed Central

    Rubio, Marta; Avitabile, Daniele; Fischer, Kimberlee; Emmanuel, Gregory; Gude, Natalie; Miyamoto, Shigeki; Mishra, Shikha; Schaefer, Eric M.; Brown, Joan Heller; Sussman, Mark A.

    2009-01-01

    The phosphoinositide-3-kinase (PI3K) / phosphoinositide dependent kinase 1 (PDK1) signaling pathway exerts cardioprotective effects in the myocardium through activation of key proteins including Akt. Activated Akt accumulates in nuclei of cardiomyocytes suggesting that biologically relevant targets are located in that subcellular compartment. Nuclear Akt activity could be potentiated in both intensity and duration by the presence of a nuclear-associated PI3K / PDK1 signaling cascade as has been described in other non-myocyte cell types. PI3K / PDK1 distribution was determined in vitro and in vivo by immunostaining and nuclear extraction of cultured rat neonatal cardiomyocytes or transgenic mouse hearts. Results show that PI3K and PDK1 are present at a basal level in cardiomyocytes nuclei and that cardioprotective stimulation with atrial natriuretic peptide (ANP) increases their nuclear localization. In comparison, overexpression of nuclear-targeted Akt does not mediate increased translocation of either PI3K or PDK1 indicating that accumulation of Akt does not drive PI3K or PDK1 into the nuclear compartment. Furthermore, PI3K and phospho-Akt473 show parallel temporal accumulation in the nucleus following (MI) infarction challenge. These findings demonstrate the presence of a dynamically regulated nuclear-associated signaling cascade involving PI3K and PDK that presumably influences nuclear Akt activation. PMID:19269295

  3. Avian Reovirus Protein p17 Functions as a Nucleoporin Tpr Suppressor Leading to Activation of p53, p21 and PTEN and Inactivation of PI3K/AKT/mTOR and ERK Signaling Pathways.

    PubMed

    Huang, Wei-Ru; Chiu, Hung-Chuan; Liao, Tsai-Ling; Chuang, Kuo-Pin; Shih, Wing-Ling; Liu, Hung-Jen

    2015-01-01

    Avian reovirus (ARV) protein p17 has been shown to regulate cell cycle and autophagy by activation of p53/PTEN pathway; nevertheless, it is still unclear how p53 and PTEN are activated by p17. Here, we report for the first time that p17 functions as a nucleoporin Tpr suppressor that leads to p53 nuclear accumulation and consequently activates p53, p21, and PTEN. The nuclear localization signal (119IAAKRGRQLD128) of p17 has been identified for Tpr binding. This study has shown that Tpr suppression occurs by p17 interacting with Tpr and by reducing the transcription level of Tpr, which together inhibit Tpr function. In addition to upregulation of PTEN by activation of p53 pathway, this study also suggests that ARV protein p17 acts as a positive regulator of PTEN. ARV p17 stabilizes PTEN by stimulating phosphorylation of cytoplasmic PTEN and by elevating Rak-PTEN association to prevent it from E3 ligase NEDD4-1 targeting. To activate PTEN, p17 is able to promote β-arrestin-mediated PTEN translocation from the cytoplasm to the plasma membrane via a Rock-1-dependent manner. The accumulation of p53 in the nucleus induces the PTEN- and p21-mediated downregulation of cyclin D1 and CDK4. Furthermore, Tpr and CDK4 knockdown increased virus production in contrast to depletion of p53, PTEN, and LC3 reducing virus yield. Taken together, our data suggest that p17-mediated Tpr suppression positively regulates p53, PTEN, and p21 and negatively regulates PI3K/AKT/mTOR and ERK signaling pathways, both of which are beneficial for virus replication. PMID:26244501

  4. Avian Reovirus Protein p17 Functions as a Nucleoporin Tpr Suppressor Leading to Activation of p53, p21 and PTEN and Inactivation of PI3K/AKT/mTOR and ERK Signaling Pathways.

    PubMed

    Huang, Wei-Ru; Chiu, Hung-Chuan; Liao, Tsai-Ling; Chuang, Kuo-Pin; Shih, Wing-Ling; Liu, Hung-Jen

    2015-01-01

    Avian reovirus (ARV) protein p17 has been shown to regulate cell cycle and autophagy by activation of p53/PTEN pathway; nevertheless, it is still unclear how p53 and PTEN are activated by p17. Here, we report for the first time that p17 functions as a nucleoporin Tpr suppressor that leads to p53 nuclear accumulation and consequently activates p53, p21, and PTEN. The nuclear localization signal (119IAAKRGRQLD128) of p17 has been identified for Tpr binding. This study has shown that Tpr suppression occurs by p17 interacting with Tpr and by reducing the transcription level of Tpr, which together inhibit Tpr function. In addition to upregulation of PTEN by activation of p53 pathway, this study also suggests that ARV protein p17 acts as a positive regulator of PTEN. ARV p17 stabilizes PTEN by stimulating phosphorylation of cytoplasmic PTEN and by elevating Rak-PTEN association to prevent it from E3 ligase NEDD4-1 targeting. To activate PTEN, p17 is able to promote β-arrestin-mediated PTEN translocation from the cytoplasm to the plasma membrane via a Rock-1-dependent manner. The accumulation of p53 in the nucleus induces the PTEN- and p21-mediated downregulation of cyclin D1 and CDK4. Furthermore, Tpr and CDK4 knockdown increased virus production in contrast to depletion of p53, PTEN, and LC3 reducing virus yield. Taken together, our data suggest that p17-mediated Tpr suppression positively regulates p53, PTEN, and p21 and negatively regulates PI3K/AKT/mTOR and ERK signaling pathways, both of which are beneficial for virus replication.

  5. 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

  6. Epstein-Barr virus envelope glycoprotein gp350 induces NF-kappaB activation and IL-1beta synthesis in human monocytes-macrophages involving PKC and PI3-K.

    PubMed

    D'Addario, M; Ahmad, A; Xu, J W; Menezes, J

    1999-12-01

    Epstein-Barr virus (EBV) is a highly immunotropic human herpesvirus with oncogenic potential and is involved in numerous pathologies. EBV utilizes its major envelope glycoprotein gp350 to bind to its receptor CR2/CD21 on target cells for initiating the infection. We have previously shown that EBV is able to modulate transcription and translation of a number of cytokine genes via its gp350-mediated binding to this receptor. However, the effects of the binding of purified gp350 to CR2/CD21 on plastic-adherent monocyte-macrophages (AMM) have not been investigated. These cells are a rich source of potent proinflammatory and immune-modulating cytokines, and express low levels of CR2/CD21. We show here for the first time that recombinant gp350 (rgp350) causes production of the potent proinflammatory cytokine IL-1beta in human AMM. Surprisingly, rgp350 is comparable in this capacity to the phorbol ester 12-0-tetradecanoylphorbol 13-acetate. This induction of IL-1beta production was accompanied by increased steady-state levels of its mRNA in gp350-treated AMM, and was dependent on the specific binding of rgp350 to the EBV receptor CR2/CD21. We also show that the signaling pathways resulting in the induction of IL-1beta synthesis by rgp350 required protein kinase C and phosphatidylinos