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Sample records for pi3k pathway activation

  1. PI3K pathway in NSCLC

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    Alex eMartínez Martí

    2012-01-01

    Full Text Available The phosphatidylinositol 3-kinases (PI3Ks are members of a family of intracellular lipid kinases that phosphorylate the 3’-hydroxyl group of phosphatidylinositol and phosphoinositides. PI3K regulate signaling pathways for neoplasia, including cell proliferation, adhesion, survival and motility. Different classes of PI3K have distinct roles in cellular signal transduction. PI3K pathway is activated by several different mechanisms in cancers, including, somatic mutation and gene amplification. In this review, we examine the literature addressing PI3K mutation status and gene amplification, with an emphasis on non-small cell lung cancer (NSCLC.

  2. Insulin induces drug resistance in melanoma through activation of the PI3K/Akt pathway

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    Chi M

    2014-02-01

    Full Text Available Mengna Chi,1 Yan Ye,1 Xu Dong Zhang,1 Jiezhong Chen2,3 1School of Medicine and Public Health, The University of Newcastle, Newcastle, NSW, Australia; 2School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia; 3Faculty of Science, Medicine and Health, The University of Wollongong, Wollongong, NSW, Australia Introduction: There is currently no curative treatment for melanoma once the disease spreads beyond the original site. Although activation of the PI3K/Akt pathway resulting from genetic mutations and epigenetic deregulation of its major regulators is known to cause resistance of melanoma to therapeutic agents, including the conventional chemotherapeutic drug dacarbazine and the Food and Drug Administration-approved mutant BRAF inhibitors vemurafenib and dabrafenib, the role of extracellular stimuli of the pathway, such as insulin, in drug resistance of melanoma remains less understood. Objective: To investigate the effect of insulin on the response of melanoma cells to dacarbazine, and in particular, the effect of insulin on the response of melanoma cells carrying the BRAFV600E mutation to mutant BRAF inhibitors. An additional aim was to define the role of the PI3K/Akt pathway in the insulin-triggered drug resistance. Methods: The effect of insulin on cytotoxicity induced by dacarbazine or the mutant BRAF inhibitor PLX4720 was tested by pre-incubation of melanoma cells with insulin. Cytotoxicity was determined by the MTS assay. The role of the PI3K/Akt pathway in the insulin-triggered drug resistance was examined using the PI3K inhibitor LY294002 and the PI3K and mammalian target of rapamycin dual inhibitor BEZ-235. Activation of the PI3K/Akt pathway was monitored by Western blot analysis of phosphorylated levels of Akt. Results: Recombinant insulin attenuated dacarbazine-induced cytotoxicity in both wild-type BRAF and BRAFV600E melanoma cells, whereas it also reduced killing of BRAFV600E melanoma cells by PLX4720

  3. Ras Activated ERK and PI3K Pathways Differentially Affect Directional Movement of Cultured Fibroblasts

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    Leandra Sepe

    2013-01-01

    Full Text Available Background: Cell migration is essential in physiological and pathological processes, such as wound healing and metastasis formation. Ras involvement in these processes has been extensively demonstrated. This work attempts to characterize Ras regulation of the phenomena determining directional cell migration by separately analyzing the role of its principal effector pathways, MAPK and PI3K. Methods: NIH3T3 and NIHRasV12 fibroblasts were followed in wound healing assays to study, in time and under a directional stimulus, cell migration both under standard conditions and in presence of MAPK and PI3K inhibitors. Several parameters, descriptive of specific aspects of cell motion, were evaluated by coupling dynamic microscopy with quantitative and statistical methods. Quantitative Western Blots coupled with immunofluorescence stainings, were used to evaluate ERK activation. Results: Constitutive RasV12 activation confers to NIH3T3 the ability to close the wound faster. Neither increased cell proliferation nor higher speed explains the accelerated healing, but the increased directional migration drives the wound closure. Inhibition of ERK activation, which occurs immediately after wound, greatly blocks the directional migration, while inhibition of PI3K pathway reduces cell speed but does not prevent wound closure. Conclusion: Ras is greatly involved in determining and regulating directionality, ERK is its key effector for starting, driving and regulating directional movement.

  4. PI3K-Akt signaling pathway upregulates hepatitis C virus RNA translation through the activation of SREBPs.

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    Shi, Qing; Hoffman, Brett; Liu, Qiang

    2016-03-01

    Hepatitis C virus (HCV) activates PI3K-Akt signaling to enhance entry and replication. Here, we found that this pathway also increased HCV translation. Knocking down the three Akt isoforms significantly decreased, whereas ectopic expression increased HCV translation. HCV translation upregulation by Akt required their kinase activities because Akt kinase-dead mutants downregulated HCV translation; and was dependent on PI3K activity since it was sensitive to PI3K inhibitor wortmannin. The viral 3'UTR was not involved in translation upregulation by Akt. HCV NS5A increased Akt phosphorylation/activity and HCV translation in the absence of the viral 3'UTR. Sterol regulatory element-binding proteins (SREBPs) were the downstream effectors of the PI3K-Akt pathway in regulating HCV translation because Akt1 and Akt2 activated both SREBP-1 and SREBP-2, whereas Akt3 upregulated SREBP-1. Knocking down SREBPs significantly decreased, while ectopic expression of SREBPs increased HCV translation. Taken together, we showed that the PI3K-Akt signaling pathway positively regulates HCV translation through SREBPs.

  5. Effects of AFP-activated PI3K/Akt signaling pathway on cell proliferation of liver cancer.

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    Zheng, Lu; Gong, Wei; Liang, Ping; Huang, XiaoBing; You, Nan; Han, Ke Qiang; Li, Yu Ming; Li, Jing

    2014-05-01

    This study aims to investigate effects of alpha-fetoprotein (AFP)-activated phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signaling pathway on hepatocellular carcinoma cell proliferation. Active cirrhosis patients after hepatitis B infection (n = 20) and viral hepatitis patients with hepatocellular carcinoma (HCC) (n = 20) were selected as the subjects of the present study. Another 20 healthy subjects were selected as the control group. The serum AFP expression and liver tissue PI3K and Akt gene mRNA expression were detected. The hepatoma cell model HepG2 which had a stable expression of AFP gene was used. Real-time quantitative PCR and Western blot and other methods were used to analyze the intracellular PI3K and Akt protein levels. Compared with control group and cirrhosis group, the serum AFP levels in HCC group significantly increased, and the tissue PI3K and Akt mRNA expression also significantly increased. HepG2 cells were intervened using AFP, in which the PIK and Akt protein expression significantly increased. After intervention by use of AFP monoclonal antibodies or LY294002 inhibitor, the PIK and Akt protein expression in HepG2 cell was significantly decreased (P AFP can promote the proliferation of hepatoma cells via activation of PI3K/Akt signaling pathway.

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

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    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.

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

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    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 (Pinhibition 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.

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

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    Wu, Juanjuan, E-mail: jwu32@emory.edu [Department of Gynecology and Obstetrics, Emory University School of Medicine, 101 Woodruff Circle, Suite 4211 WMB, Atlanta, GA 30322 (United States); Williams, Devin [Department of Obstetrics and Gynecology, Morehouse School of Medicine, Atlanta, GA 30310 (United States); Walter, Grant A. [Department of Gynecology and Obstetrics, Emory University School of Medicine, 101 Woodruff Circle, Suite 4211 WMB, Atlanta, GA 30322 (United States); Thompson, Winston E. [Department of Obstetrics and Gynecology, Morehouse School of Medicine, Atlanta, GA 30310 (United States); Sidell, Neil [Department of Gynecology and Obstetrics, Emory University School of Medicine, 101 Woodruff Circle, Suite 4211 WMB, Atlanta, GA 30322 (United States)

    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

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

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    Cardnell, Robert J; Feng, Ying; 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

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

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    Robert J Cardnell

    Full Text Available 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

  11. Treadmill exercise improves motor and memory functions in cerebral palsy rats through activation of PI3K-Akt pathway.

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    Jung, Sun-Young; Kim, Dae-Young

    2017-04-01

    Cerebral palsy (CP) is a chronic disorder characterized by physical disability and disruption of brain function. We evaluated the effects of treadmill exercise on motor and memory functions in relation with phosphatidylinositol 3-kinase (PI3K)-Akt pathway using CP rat model. Rota-rod test, step-down avoidance task, 5-bromo-2'-deoxyuridine (BrdU) immunohistochemistry, and western blot for synapsin I, postsynaptic density-95 (PSD-95), PI3K, Akt, and glycogen synthase kinase-3β (GSK-3β) were performed. CP was induced by maternal lipopolysaccharide (LPS)-injection with sensorimotor restriction. Five weeks after birth, the rats in the exercise groups were made to run on the treadmill for 30 min per one day, 5 times a week, during 4 weeks. Motor and memory functions were impaired in the LPS-induced CP rats and tread-mill exercise increased motor and memory functions in the CP rats. Cell proliferation in the hippocampus was suppressed in the LPS-induced CP rats and treadmill exercise increased hippocampal cell proliferation in the CP rats. Expressions of synapsin I, PSD-95, phosphorylated (p)-PI3K, and p-Akt were decreased in the LPS-induced CP rats and treadmill exercise enhanced the expressions of synapsin I, PSD-95, p-PI3K, and p-Akt in the CP rats. GSK-3β expression was increased in the LPS-induced CP rats and treadmill exercise suppressed GSK-3β expression in the CP rats. The present results suggest that treadmill exercise might improve motor and memory functions through activation of PI3K-Akt pathway.

  12. Targeting of PI3K/AKT/mTOR pathway to inhibit T cell activation and prevent graft-versus-host disease development

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    Mª Carmen Herrero-Sánchez

    2016-10-01

    Full Text Available Abstract Background Graft-versus-host disease (GvHD remains the major obstacle to successful allogeneic hematopoietic stem cell transplantation, despite of the immunosuppressive regimens administered to control T cell alloreactivity. PI3K/AKT/mTOR pathway is crucial in T cell activation and function and, therefore, represents an attractive therapeutic target to prevent GvHD development. Recently, numerous PI3K inhibitors have been developed for cancer therapy. However, few studies have explored their immunosuppressive effect. Methods The effects of a selective PI3K inhibitor (BKM120 and a dual PI3K/mTOR inhibitor (BEZ235 on human T cell proliferation, expression of activation-related molecules, and phosphorylation of PI3K/AKT/mTOR pathway proteins were analyzed. Besides, the ability of BEZ235 to prevent GvHD development in mice was evaluated. Results Simultaneous inhibition of PI3K and mTOR was efficient at lower concentrations than PI3K specific targeting. Importantly, BEZ235 prevented naïve T cell activation and induced tolerance of alloreactive T cells, while maintaining an adequate response against cytomegalovirus, more efficiently than BKM120. Finally, BEZ235 treatment significantly improved the survival and decreased the GvHD development in mice. Conclusions These results support the use of PI3K inhibitors to control T cell responses and show the potential utility of the dual PI3K/mTOR inhibitor BEZ235 in GvHD prophylaxis.

  13. Oxymatrine synergistically enhances antitumor activity of oxaliplatin in colon carcinoma through PI3K/AKT/mTOR pathway.

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    Liu, Yan; Bi, Tingting; Wang, Zheng; Wu, Guoliang; Qian, Liqiang; Gao, Quangen; Shen, Genhai

    2016-12-01

    Oxymatrine (OMT), one of the main active components of extracts from the dry roots of Sophora flavescens, has been reported to possess many pharmacological properties including cancer-preventive and anti-cancer effects. The aim of the present study is to explore the efficiency of combination therapy with OMT and oxaliplatin (OXA) and identify the in vitro and in vivo cytotoxicity on colon cancer lines (HT29 and SW480) and mice model. Cells were treated with OMT and/or OXA and subjected to cell viability, colony formation, apoptosis, cell cycle, western blotting, xenograft tumorigenicity assay and immunohistochemistry. The results demonstrated that OMT and OXA inhibited the proliferation of colon cancer cells, and combination therapy of OMT and OXA resulted in a combination index OMT and OXA caused G0/G1 phase arrest by upregulating P21, P27 and downregulating cyclin D, and induced apoptosis through decreasing the expression of p-PI3K, p-AKT, p-mTOR, p-p70S6K. In addition, pretreatment with a specific PI3K/AKT activator (IGF-1) significantly neutralized the pro-apoptotic activity of OXA + OMT, demonstrating the important role of PI3K/AKT in this process. Moreover, in nude mice model, co-treatment displayed more efficient inhibition of tumor weight and volume on SW480 xenograft mouse model than single-agent treatment with OXA or OMT. Immunohistochemistry analysis suggests the combinations greatly suppressed tumor proliferation, which consistent with our in vitro results. In conclusion, our findings highlight that the combination therapy with OMT and OXA exerted synergistic antitumor effects in colon cancer cells through PI3K/AKT/mTOR pathway and combination treatment with OMT and OXA would be a promising therapeutic strategy for colon carcinoma treatment.

  14. Interleukin-18 directly protects cortical neurons by activating PI3K/AKT/NF-κB/CREB pathways.

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    Zhou, Jia; Ping, Feng-feng; Lv, Wen-ting; Feng, Jun-yi; Shang, Jing

    2014-09-01

    Interleukin-18 (IL-18), a member of the IL-1 family of cytokines, was initially identified as an interferon (IFN)-γ-inducing factor. IL-18 is expressed in both immune and non-immune cells and participates in the adjustment of multitude cellular functions. Nonetheless, the effects of IL-18 on cortical neurons have not been explored. The present study was conducted to investigate the influence of IL-18 on rat primary cortical neurons and elucidate the underlying mechanisms. We proved that rrIL-18 increased the brain-derived neurotrophic factor (BDNF) expression in a time-dependent manner. Treatment with rrIL-18 (50 ng/ml) deactivated phosphatase and tensin homolog deleted on chromosome 10 (PTEN) by facilitating its phosphorylation, enhanced the expression of Phosphoinositide 3-OH kinase (PI3K) and p-Akt, standing for the activation of the PI3K/Akt pathway. As its pivotal downstream pathways, nuclear factor-kappa B (NF-κB), cAMP-responsive element binding protein (CREB)/Bcl-2 and glycogen synthase kinase-3β (GSK-3β) were examined in further steps. Our data revealed that rrIL-18 stimulated NF-κB activation, improved p-CREB and anti-apoptotic Bcl-2 expression levels. But rrIL-18 had little or no effect on GSK-3β pathway. Besides, rrIL-18 increased levels of BDNF and Bcl-2/Bax ratio and decreased cleaved caspase-3 expression to protect cortical neurons from damage induced by oxygen-glucose deprivation (OGD). These results in vitro showed the protection of IL-18 on cortical neurons. And this direct neuroprotective effect of IL-18 is crippled by PI3K inhibitor wortmannin.

  15. Endomembrane PtdIns(3,4,5)P3 activates the PI3K-Akt pathway.

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    Jethwa, Nirmal; Chung, Gary H C; Lete, Marta G; Alonso, Alicia; Byrne, Richard D; Calleja, Véronique; Larijani, Banafshé

    2015-09-15

    PKB/Akt activation is a common step in tumour growth, proliferation and survival. Akt activation is understood to occur at the plasma membrane of cells in response to growth factor stimulation and local production of the phosphoinositide lipid phosphatidylinositol (3,4,5)-trisphosphate [PtdIns(3,4,5)P3] following phosphoinositide 3-kinase (PI3K) activation. The metabolism and turnover of phosphoinositides is complex--they act as signalling molecules as well as structural components of biological membranes. The localisation and significance of internal pools of PtdIns(3,4,5)P3 has long been speculated upon. By using transfected and recombinant protein probes for PtdIns(3,4,5)P3, we show that PtdIns(3,4,5)P3 is enriched in the nuclear envelope and early endosomes. By exploiting an inducible dimerisation device to recruit Akt to these compartments, we demonstrate that Akt can be locally activated in a PtdIns(3,4,5)P3-dependent manner and has the potential to phosphorylate compartmentally localised downstream substrates. This could be an important mechanism to regulate Akt isoform substrate specificity or influence the timing and duration of PI3K pathway signalling. Defects in phosphoinositide metabolism and localisation are known to contribute to cancer, suggesting that interactions at subcellular compartments might be worthwhile targets for therapeutic intervention.

  16. Staying alive: PI3K pathway promotes primordial follicle activation and survival in response to 3MC-induced ovotoxicity.

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    Sobinoff, Alexander P; Nixon, Brett; Roman, Shaun D; McLaughlin, Eileen A

    2012-07-01

    3-Methylcholanthrene (3MC) is a potent ovotoxicant capable of causing premature ovarian failure through primordial follicle depletion. Despite 3MCs ovotoxicity having been established for 30 years, relatively little information exists on the mechanisms. In this study, we examined the effects of 3MC exposure on the immature ovarian follicle population. Microarray analysis revealed a complex mechanism of 3MC-induced ovotoxicity involving a number of cellular processes associated with xenobiotic metabolism, ovarian cancer, cell cycle progression, and cell death. 3MC exposure was also found to induce developing follicle atresia and aberrant primordial follicle activation via the stimulation of PI3K/Akt and mammalian target of rapamycin (mTOR) signaling pathways. Inhibition of PI3K/Akt signaling resulted in the severe depletion of the primordial follicle pool, with further analysis identifying increased Akt1-stimulated Bad phosphoinhibition in 3MC-treated primordial follicles. Our results suggest that the primordial follicle pool enters a "prosurvival" state upon 3MC exposure and that its depletion is due to a vicious cycle of primordial follicle activation in an attempt to replace developing follicles undergoing follicular atresia.

  17. β-Caryophyllene Pretreatment Alleviates Focal Cerebral Ischemia-Reperfusion Injury by Activating PI3K/Akt Signaling Pathway.

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    Zhang, Qian; An, Ruidi; Tian, Xiaocui; Yang, Mei; Li, Minghang; Lou, Jie; Xu, Lu; Dong, Zhi

    2017-02-24

    β-Caryophyllene (BCP) has been reported to be protective against focal cerebral ischemia-reperfusion (I/R) injury by its anti-oxidative and anti-inflammatory features. Recent study demonstrates that the BCP exhibits potential neuroprotection against I/R injury induced apoptosis, however, the mechanism remains unknown. Therefore, we investigate the underlying anti-apoptotic mechanism of BCP pretreatment in I/R injury. Sprague-Dawley rats (pretreated with BCP suspensions or solvent orally for 7 days) were subjected to transient Middle Cerebral Artery Occlusion (MCAO) for 90 min, followed by 24 h reperfusion. Results showed that BCP pretreatment improved the neurologic deficit score, lowered the infarct volume and decreased number of apoptotic cells in the hippocampus. Moreover, in western blot and RT-qPCR detections, BCP pretreatment down-regulated the expressions of Bax and p53, up-regulated the expression of Bcl-2, and enhanced the phosphorylation of Akt on Ser473. Blockage of PI3K activity by wortmannin not only abolished the BCP-induced decreases in infarct volume and neurologic deficit score, but also dramatically abrogated the enhancement of AKt phosphorylation. Our results suggested that BCP pre-treatment protects against I/R injury partly by suppressing apoptosis via PI3K/AKt signaling pathway activation.

  18. MicroRNA 181b promotes vascular smooth muscle cells proliferation through activation of PI3K and MAPK pathways.

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    Li, Tie-Jun; Chen, Yan-Li; Gua, Chao-Jun; Xue, Sheng-Jiang; Ma, Shu-Mei; Li, Xiao-Dong

    2015-01-01

    Vascular smooth muscle cells (VSMCs) hyperplasia is a common feature of pathologic cardiovascular event such as restenosis and atherosclerosis. The role and mechanisms of microRNAs (miRs) in VSMCs proliferation are poorly understood. Here, we report that miR-181b promotes VSMCs proliferation and migration. In an animal model, miR-181b was significantly increased in the rat carotid artery after balloon catheter injury. Delivery of miR-181b inhibitor to injured artery exhibited a marked inhibition of neointimal hyperplasia. Transfection of miR-181b with "mimics" to A10 cells accelerated cell proliferation, which was accompanied by an increase of cell migration. The induction of A10 cells proliferation by miR-181b appeared to be involved in activation of S and G2/M checkpoint, concomitant with decreases in cell-cycle inhibitors p21 and p27, and increases in cell-cycle activators CDK4 and cyclinD1. In contract, miR-181b inhibition attenuated A10 cells proliferation, inhibited cell migration and arrested cell cycle transition. Moreover, forced miR-181b expression elevated the phosphorylation levels of Akt and Erk1/2, whereas inhibition of miR-181b produced the opposite effects. Additionally, inhibition of PI3K and MAPK signaling pathways with specific inhibitors, but not inhibition of JNK pathway, significantly abolished the effects of miR-181b in promoting cell proliferation. These findings demonstrate that miR-181b enhances the proliferation and migration of VSMCs through activation of PI3K and MAPK pathways.

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

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    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.

  20. Expression of the RAE-1 Family of Stimulatory NK-Cell Ligands Requires Activation of the PI3K Pathway during Viral Infection and Transformation

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    Tokuyama, Maria; Lorin, Clarisse; Delebecque, Frederic; Jung, Heiyoun; Raulet, David H.; Coscoy, Laurent

    2011-01-01

    Natural killer (NK) cells are lymphocytes that play a major role in the elimination of virally-infected cells and tumor cells. NK cells recognize and target abnormal cells through activation of stimulatory receptors such as NKG2D. NKG2D ligands are self-proteins, which are absent or expressed at low levels on healthy cells but are induced upon cellular stress, transformation, or viral infection. The exact molecular mechanisms driving expression of these ligands remain poorly understood. Here we show that murine cytomegalovirus (MCMV) infection activates the phosphatidylinositol-3-kinase (PI3K) pathway and that this activation is required for the induction of the RAE-1 family of mouse NKG2D ligands. Among the multiple PI3K catalytic subunits, inhibition of the p110α catalytic subunit blocks this induction. Similarly, inhibition of p110α PI3K reduces cell surface expression of RAE-1 on transformed cells. Many viruses manipulate the PI3K pathway, and tumors frequently mutate the p110α oncogene. Thus, our findings suggest that dysregulation of the PI3K pathway is an important signal to induce expression of RAE-1, and this may represent a commonality among various types of cellular stresses that result in the induction of NKG2D ligands. PMID:21966273

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

    Science.gov (United States)

    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.

  2. Panaxatriol Saponins Attenuated Oxygen-Glucose Deprivation Injury in PC12 Cells via Activation of PI3K/Akt and Nrf2 Signaling Pathway

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    Yongliang Huang

    2014-01-01

    Full Text Available Panaxatriol saponins (PTS, the main components extracted from Panax notoginseng, have been shown to be efficacious in the prevention and treatment of cerebrovascular diseases in China. NF-E2-related factor 2 (Nrf2, a transcription factor regulating antioxidant and cytoprotective responses to oxidative stress, has received particular attention as a molecular target for pharmacological intervention of ischemic diseases. The aim of this study was to characterize the effect of PTS on the activation of Nrf2 signaling pathway and the potential role in its protective effect. We found that PTS induced heme oxygenase-1 (HO-1 expression in PC12 cells via activating Nrf2 signaling pathway. Phosphatidylinositol 3-kinase (PI3K/Akt kinase was involved in the upstream of this PTS activated pathway. Moreover, combination of the main components in PTS significantly enhanced the expression of Nrf2 mediated phase II enzymes. Importantly, the protective effect of PTS against oxygen-glucose deprivation-reperfusion (OGD-Rep induced cell death was significantly attenuated by PI3K inhibitor and antioxidant response element (ARE decoy oligonucleotides, suggesting that both PI3K/Akt and Nrf2 signaling pathway are essential during this protective process. Taken together, our results suggest that PTS may activate endogenous cytoprotective mechanism against OGD-Rep induced oxidative injury via the activation of PI3K/Akt and Nrf2 signaling pathway.

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

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Changjiang [MOE Key Lab of Environment and Health, Department of Occupational and Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030 (China); Key Lab of Birth Defects and Reproductive Health of National Health and Family Planning Commission, Chongqing Population and Family Planning Science and Technology Research Institute, Chongqing 400020 (China); Yang, Jixin [Department of Pediatric Surgery, Tongji Hospital, Huazhong University of Science and Technology, Wuhan 430030 (China); Fu, Wenjuan; Qi, Suqin; Wang, Chenmin; Quan, Chao [MOE Key Lab of Environment and Health, Department of Occupational and Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030 (China); Yang, Kedi, E-mail: yangkd@mails.tjmu.edu.cn [MOE Key Lab of Environment and Health, Department of Occupational and Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030 (China)

    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. Beauvericin ameliorates experimental colitis by inhibiting activated T cells via downregulation of the PI3K/Akt signaling pathway.

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    Xue-Feng Wu

    Full Text Available Crohn's disease is a common, chronic inflammatory bowel condition characterized by remission and relapse. Accumulating evidence indicates that activated T cells play an important role in this disease. In the present study, we aimed to examine the effect of beauvericin, a natural cyclic peptide, on 2,4,6-trinitrobenzene sulfonic acid (TNBS-induced colitis in mice, which mimics Crohn's disease. Beauvericin significantly reduced weight loss, diarrhea and mortality, accompanied with notable alleviation of macroscopic and microscopic signs. In addition, this compound decreased serum levels of tumor necrosis factor (TNF-α and interferon (IFN-γ in a concentration-dependent manner in mice with experimental colitis. These effects of beauvericin are attributed to its inhibition on activated T cells. Flow cytometry and immunoblot assay data showed that beauvericin suppressed T-cell proliferation, activation and IFN-γ-STAT1-T-bet signaling and subsequently led to apoptosis of activated T cells by suppressing Bcl-2 and phosphorylated Bad as well as increasing cleavage of caspase-3, -9, -12 and PARP. Furthermore, inhibition of PI3K/Akt signaling, which was an upstream regulator of cell activation and survival in activated T cells, contributed to the effect of beauvericin. Overall, these results supported beauvericin as a novel drug candidate for the treatment of colonic inflammation mainly by targeting PI3K/Akt in activated T cells.

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

    Science.gov (United States)

    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.

  6. Upstream and Downstream Co-inhibition of Mitogen-Activated Protein Kinase and PI3K/Akt/mTOR Pathways in Pancreatic Ductal Adenocarcinoma

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    Matthew H. Wong

    2016-07-01

    Full Text Available BACKGROUND: Extensive cross talk exists between PI3K/Akt/mTOR and mitogen-activated protein kinase (MAPK pathways, and both are upregulated in pancreatic ductal adenocarcinoma (PDAC. Our previous study suggested that epidermal growth factor receptor inhibitor erlotinib which acts upstream of these pathways acts synergistically with PI3K inhibitors in PDAC. Horizontal combined blockade upstream and downstream of these two pathways is therefore explored. METHODS: Erlotinib paired with PI3K inhibitor (BYL719 was tested against erlotinib plus dual PI3K/mTOR inhibitor BEZ-235, and MEK inhibitor (PD98059 plus BEZ235, on five primary PDAC cell lines and on two pairs of parent and erlotinib-resistant (ER cell lines. A range of in vitro assays including cell proliferation, Western blotting, migration, clonogenic, cell cycle, and apopotic assays was used to test for the efficacy of combined blockade. RESULTS: Dual downstream blockade of the MAPK and PAM pathways was more effective in attenuating downstream molecular signals. Synergy was demonstrated for erlotinib and BEZ235 and for PD-98059 and BEZ-235. This resulted in a trend of increased growth cell cycle arrest, apoptosis, cell proliferation, and colony and migration suppression. This combination showed more efficacy in cell lines with acquired resistance to erlotinib. CONCLUSIONS: The additional mTOR blockade provided by BEZ235 in combined blockade resulted in increased anticancer effect. The hypersensitivity of ER cell lines to additional mTOR blockade suggested PAM pathway oncogenic dependence via mTOR. Dual downstream combined blockade of MAPK and PAM pathways with MEK and PI3K/mTOR inhibitor appeared most effective and represents an attractive therapeutic strategy against pancreatic cancer and its associated drug resistance.

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

    Energy Technology Data Exchange (ETDEWEB)

    Hinoi, Eiichi; Iezaki, Takashi; Fujita, Hiroyuki; Watanabe, Takumi; Odaka, Yoshiaki; Ozaki, Kakeru; Yoneda, Yukio, E-mail: yyoneda@p.kanazawa-u.ac.jp

    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.

  8. SMND-309 promotes neuron survival through the activation of the PI3K/Akt/CREB-signalling pathway.

    Science.gov (United States)

    Wang, Youlei; Zhang, Jinjin; Han, Meng; Liu, Bo; Gao, Yulin; Ma, Peng; Zhang, Songzi; Zheng, Qingyin; Song, Xiaodong

    2016-10-01

    Context In clinical practice, the promotion of neuron survival is necessary to recover neurological functions after the onset of stroke. Objective This study aimed to investigate the post-ischaemic neuroprotective effect of SMND-309, a novel metabolite of salvianolic acid, on differentiated SH-SY5Y cells. Materials and methods SH-SY5Y cells were differentiated by pre-treating with 5 μM all-trans-retinoic acid for 6 d. The differentiated SH-SY5Y cells were exposed to oxygen-glucose deprivation (OGD) for 2 h and reperfusion (R) for 24 h to induce OGD/R injury. After OGD injury, differentiated SH-SY5Y cells were treated with or without SMND-309 (5, 10, 20 μM) for another 24 h. Cell viability was detected through Cell counting kit-8 assay and lactate dehydrogenase leakage assay. Apoptosis was evaluated through flow cytometry, caspase-3 activity assay. Changes in protein levels were assessed through Western blot. Results SMND-309 ameliorated the degree of injury in the differentiated SH-SY5Y cells by increasing cell viabilities (5 μM, 65.4% ± 4.1%; 10 μM, 69.8% ± 3.7%; 20 μM, 75.3% ± 5.1%) and by reducing LDH activity (20 μM, 2.5 fold) upon OGD/R stimulation. Annexin V-fluorescein isothiocyanate/propidium iodide staining results suggested that apoptotic rate of differentiated SH-SY5Y cells decreased from 43.8% induced by OGD/R injury to 19.2% when the cells were treated with 20 μM SMND-309. SMND-309 significantly increased the Bcl-2 level of the injured differentiated SH-SY5Y cells but decreased the caspase-3 activity of these cells by 1.6-fold. In contrast, SMND-309 did not affect the Bax level of these cells. SMND-309 evidently increased the protein expression of BDNF when Akt and CREB were activated. This function was antagonized by the addition of LY294002. Conclusion SMND-309 can prevent neuronal cell death in vitro. This process may be related to the activation of the PI3K/Akt/CREB-signalling pathway.

  9. Neuroprotection of selenite against ischemic brain injury through negatively regulating early activation of ASK1/JNK cascade via activation of PI3K/AKT pathway

    Institute of Scientific and Technical Information of China (English)

    Qing WANG; Quan-guang ZHANG; Dong-na WU; Xiao-hui YIN; Guang-yi ZHANG

    2007-01-01

    Aim: To investigate whether selenite, a known antioxidant, could decrease the activation of apoptosis signal regulating kinase 1/c-jun N-terminal kinase (ASK1/JNK) signaling cascade in cerebral ischemia/reperfusion (I/R) by activating the phosphatidylinositol 3-kinase (PI3K)/AKT pathway in rat hippocampi, and the neuroprotective effect of selenite against ischemic injury after 15 min of transient brain ischemia. Methods: Transient global brain ischemia was induced by 4-vessel occlusion into adult male Sprague-Dawley rats weighing 250-300 g. The rats were pretreated only with selenite (0.3 mg/kg dissolved in 0.9% saline) every 24 h for 7 d by means of intravenous injection of the tail or combined with LY294002 from d 5 by left cerebral ventricle'injection before surgery. Results: Selenite significantly increased AKT1 activation and decreased the activation of ASK1/JNK cascade via phosphorylating ASK1 at Ser-83 residue by AKT1 during early reperfusion after 15 min transient global brain ischemia. On the contrary, com-bined pretreatment of the rats with LY294002 (a specific PI3K inhibitor) and selen-ite significantly inhibited the effects solely with selenite. Conclusion: The activa-tion of the pro-apoptotic ASK1/JNK cascade, which is closely associated with oxidative stress, could be suppressed by selenite through activating the anti-apoptotic PI3K/AKT pathway during early reperfusion after cerebral ischemia in rat hippocampi.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

  12. Anti-myeloma activity of Akt inhibition is linked to the activation status of PI3K/Akt and MEK/ERK pathway.

    Science.gov (United States)

    Ramakrishnan, Vijay; Kimlinger, Teresa; Haug, Jessica; Painuly, Utkarsh; Wellik, Linda; Halling, Timothy; Rajkumar, S Vincent; Kumar, Shaji

    2012-01-01

    The PI3K/Akt/mTOR signal transduction pathway plays a central role in multiple myeloma (MM) disease progression and development of therapeutic resistance. mTORC1 inhibitors have shown limited efficacy in the clinic, largely attributed to the reactivation of Akt due to rapamycin induced mTORC2 activity. Here, we present promising anti-myeloma activity of MK-2206, a novel allosteric pan-Akt inhibitor, in MM cell lines and patient cells. MK-2206 was able to induce cytotoxicity and inhibit proliferation in all MM cell lines tested, albeit with significant heterogeneity that was highly dependent on basal pAkt levels. MK-2206 was able to inhibit proliferation of MM cells even when cultured with marrow stromal cells or tumor promoting cytokines. The induction of cytotoxicity was due to apoptosis, which at least partially was mediated by caspases. MK-2206 inhibited pAkt and its down-stream targets and up-regulated pErk in MM cells. Using MK-2206 in combination with rapamycin (mTORC1 inhibitor), LY294002 (PI3K inhibitor), or U0126 (MEK1/2 inhibitor), we show that Erk- mediated downstream activation of PI3K/Akt pathway results in resistance to Akt inhibition. These provide the basis for clinical evaluation of MK-2206 alone or in combination in MM and potential use of baseline pAkt and pErk as biomarkers for patient selection.

  13. Anti-myeloma activity of Akt inhibition is linked to the activation status of PI3K/Akt and MEK/ERK pathway.

    Directory of Open Access Journals (Sweden)

    Vijay Ramakrishnan

    Full Text Available The PI3K/Akt/mTOR signal transduction pathway plays a central role in multiple myeloma (MM disease progression and development of therapeutic resistance. mTORC1 inhibitors have shown limited efficacy in the clinic, largely attributed to the reactivation of Akt due to rapamycin induced mTORC2 activity. Here, we present promising anti-myeloma activity of MK-2206, a novel allosteric pan-Akt inhibitor, in MM cell lines and patient cells. MK-2206 was able to induce cytotoxicity and inhibit proliferation in all MM cell lines tested, albeit with significant heterogeneity that was highly dependent on basal pAkt levels. MK-2206 was able to inhibit proliferation of MM cells even when cultured with marrow stromal cells or tumor promoting cytokines. The induction of cytotoxicity was due to apoptosis, which at least partially was mediated by caspases. MK-2206 inhibited pAkt and its down-stream targets and up-regulated pErk in MM cells. Using MK-2206 in combination with rapamycin (mTORC1 inhibitor, LY294002 (PI3K inhibitor, or U0126 (MEK1/2 inhibitor, we show that Erk- mediated downstream activation of PI3K/Akt pathway results in resistance to Akt inhibition. These provide the basis for clinical evaluation of MK-2206 alone or in combination in MM and potential use of baseline pAkt and pErk as biomarkers for patient selection.

  14. Neuroprotective effects of salidroside through PI3K/Akt pathway activation in Alzheimer’s disease models

    Science.gov (United States)

    Zhang, Bei; Wang, Ying; Li, Hui; Xiong, Ran; Zhao, Zongbo; Chu, Xingkun; Li, Qiongqiong; Sun, Suya; Chen, Shengdi

    2016-01-01

    Alzheimer’s disease (AD) is a devastating neurodegenerative disorder characterized by deposits of aggregated amyloid-β (Aβ) peptide and neurofibrillary tangles in the brain parenchyma. Despite considerable research to elucidate the pathological mechanisms and identify therapeutic strategies for AD, effective treatments are still lacking. In the present study, we found that salidroside (Sal), a phenylpropanoid glycoside isolated from Rhodiola rosea L., can protect against Aβ-induced neurotoxicity in four transgenic Drosophila AD models. Both longevity and locomotor activity were improved in Sal-fed Drosophila. Sal also decreased Aβ levels and Aβ deposition in brain and ameliorated toxicity in Aβ-treated primary neuronal culture. The neuroprotective effect of Sal was associated with upregulated phosphatidylinositide 3-kinase (PI3K)/Akt signaling. Our findings identify a compound that may possess potential therapeutic benefits for AD and other forms of neurodegeneration. PMID:27103787

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

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    Zhu Liqian

    2011-04-01

    Full Text Available Abstract 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.

  16. PI3K is an upstream regulator of the PDE3B pathway of leptin signaling that may not involve activation of Akt in the rat hypothalamus

    Science.gov (United States)

    Sahu, Abhiram; Koshinaka, Keiichi; Sahu, Maitrayee

    2012-01-01

    Leptin, the product of the obese gene, regulates energy homeostasis by acting primarily at the level of the hypothalamus. Leptin action through its receptor involves various pathways including the signal transducer and activator of transcription (STAT3), phosphatidylinositol 3-kinase (PI3K), and phosphodiesterase 3B (PDE3B)-cAMP signaling in the CNS and peripheral tissues. In the hypothalamus, leptin stimulates STAT3 activation, and induces PI3K and PDE3B activities, among others. We have previously demonstrated that PDE3B activation in the hypothalamus is critical for transducing anorectic and body weight reducing effects of leptin. Similarly, PI3K has been implicated toplay a critical role in leptin signaling in the hypothalamus. Whereas in insulin signaling pathway, PI3K is known to be an upstream regulator of PDE3B in non-neuronal tissues, it is still unknown whether this is also the case for leptin signaling in the hypothalamus. To address this possibility, the effect of wortmannin, a specific PI3K inhibitor, was examined on the leptin-induced PDE3B activity in the hypothalamus of male rats. Intracerebroventricular (icv) injection of leptin (4 μg) significantly increased PDE3B activity by 2-fold in the hypothalamus as expected. However, prior administration of wortmannin completely reversed the stimulatory effect of leptin on PDE3B activity in the hypothalamus. To demonstrate whether leptin stimulates p-Akt levels and there by a possible upstream regulator of PDE3B, we examined the effects of icv leptin on p-Akt levels in the hypothalamus and compared that with the known stimulatory effect of insulin on p-Akt. We observed that insulin increased p-Akt levels but leptin failed to do so although it increased p-STAT3 levels in the rat hypothalamus. Immunocytochemistry confirmed the biochemical finding in that leptin failed but insulin increased the number of p-Akt positive cells in various hypothalamic nuclei. Altogether these results implicate PI3K but not Akt

  17. Fucoidan Induces ROS-Dependent Apoptosis in 5637 Human Bladder Cancer Cells by Downregulating Telomerase Activity via Inactivation of the PI3K/Akt Signaling Pathway.

    Science.gov (United States)

    Han, Min Ho; Lee, Dae-Sung; Jeong, Jin-Woo; Hong, Su-Hyun; Choi, Il-Whan; Cha, Hee-Jae; Kim, Suhkmann; Kim, Heui-Soo; Park, Cheol; Kim, Gi-Young; Moon, Sung-Kwon; Kim, Wun-Jae; Hyun Choi, Yung

    2017-02-01

    Preclinical Research Fucoidan, a sulfated polysaccharide, is a compound found in various species of seaweed that has anti-viral, anti-bacterial, anti-oxidant, anti-inflammatory, and immunomodulatory activities; however, the underlying relationship between apoptosis and anti-telomerase activity has not been investigated. Here, we report that fucoidan-induced apoptosis in 5637 human bladder cancer cells was associated with an increase in the Bax/Bcl-2 ratio, the dissipation of the mitochondrial membrane potential (MMP, Δψm), and cytosolic release of cytochrome c from the mitochondria. Under the same experimental conditions, fucoidan-treatment decreased hTERT (human telomerase reverse transcriptase) expression and the transcription factors, c-myc and Sp1. This was accompanied by decreased telomerase activity. Fucoidan-treatment also suppressed activation of the PI3K/Akt signaling pathway. Inhibition of PI3K/Akt signaling enhanced fucoidan-induced apoptosis and anti-telomerase activity. Meanwhile, fucoidan treatment increased the generation of intracellular ROS, whereas the over-elimination of ROS by N-acetylcysteine, an anti-oxidant, attenuated fucoidan-induced apoptosis, inhibition of hTERT, c-myc, and Sp1 expression, and reversed fucoidan-induced inactivation of the PI3K/Akt signaling pathway. Collectively, these data indicate that the induction of apoptosis and the inhibition of telomerase activity by fucoidan are mediated via ROS-dependent inactivation of the PI3K/Akt pathway. Drug Dev Res 78 : 37-48, 2017.   © 2016 Wiley Periodicals, Inc.

  18. Luteolin enhances cholinergic activities in PC12 cells through ERK1/2 and PI3K/Akt pathways.

    Science.gov (United States)

    El Omri, Abdelfatteh; Han, Junkyu; Kawada, Kiyokazu; Ben Abdrabbah, Manef; Isoda, Hiroko

    2012-02-09

    Luteolin, a 3', 4', 5, 7-tetrahydroxyflavone, is an active compound in Rosmarinus officinalis (Lamiacea), and has been reported to exert several benefits in neuronal cells. However cholinergic-induced activities of luteolin still remain unknown. Neuronal differentiation encompasses an elaborate developmental program which plays a key role in the development of the nervous system. The advent of several cell lines, like PC12 cells, able to differentiate in culture proved to be the turning point for gaining and understanding of molecular neuroscience. In this work, we investigated the ability of luteolin to induce PC12 cell differentiation and its effect on cholinergic activities. Our findings showed that luteolin treatment significantly induced neurite outgrowth extension, enhanced acetylcholinesterase (AChE) activity, known as neuronal differentiation marker, and increased the level of total choline and acetylcholine in PC12 cells. In addition, luteolin persistently, activated extracellular signal-regulated kinase 1/2 (ERK1/2) and Akt; while the addition of pharmacological MEK/ERK1/2 inhibitor (U0126) and PI3k/Akt inhibitor (LY294002) attenuated luteolin-induced AChE activity and neurite outgrowth in PC12 cells. The above findings suggest that luteolin induces neurite outgrowth and enhanced cholinergic activities, at least in part, through the activation of ERK1/2 and Akt signaling.

  19. Erythropoietin promotes regeneration of adult CNS neurons via Jak2/Stat3 and PI3K/AKT pathway activation.

    Science.gov (United States)

    Kretz, Alexandra; Happold, Caroline J; Marticke, Julia K; Isenmann, Stefan

    2005-08-01

    The cytokine hormone erythropoietin (EPO) has proved neuroprotective in CNS injury, and clinical trials for ischemic stroke are ongoing. The capability of EPO to restore postmitotic CNS architecture and function by fibre regeneration has not been examined. Here, we compared in vitro outgrowth capacity of adult retinal ganglion cells (RGCs) following optic nerve (ON) lesion in the presence and absence of EPO. Immediate EPO conditioning in vivo, or delayed EPO treatment of cultures with 10--10,000 IU rhEPO significantly increased numbers (2.66-fold) and length (8.31-fold) of newly generated neurites, without evoking rheological complications. EPO induced Stat3 phosphorylation in RGCs, and inhibition of Jak2/Stat3 abolished EPO-induced growth. EPO-facilitated neuritogenesis was paralleled by upregulation of Bcl-X(L), a Bcl-2 homologue capable of promoting RGC regeneration. The PI3K/Akt pathway was also involved in antiapoptotic and regeneration-enhancing EPO actions. In conclusion, EPO treatment may offer a unique dual-function strategy for neuroprotection and regeneration.

  20. Skin Aging-Dependent Activation of the PI3K Signaling Pathway via Downregulation of PTEN Increases Intracellular ROS in Human Dermal Fibroblasts

    Directory of Open Access Journals (Sweden)

    Eun-Mi Noh

    2016-01-01

    Full Text Available Reactive oxygen species (ROS play a major role in both chronological aging and photoaging. ROS induce skin aging through their damaging effect on cellular constituents. However, the origins of ROS have not been fully elucidated. We investigated that ROS generation of replicative senescent fibroblasts is generated by the modulation of phosphatidylinositol 3,4,5-triphosphate (PIP3 metabolism. Reduction of the PTEN protein, which dephosphorylates PIP3, was responsible for maintaining a high level of PIP3 in replicative cells and consequently mediated the activation of the phosphatidylinositol-3-OH kinase (PI3K/Akt pathway. Increased ROS production was blocked by inhibition of PI3K or protein kinase C (PKC or by NADPH oxidase activating in replicative senescent cells. These data indicate that the signal pathway to ROS generation in replicative aged skin cells can be stimulated by reduced PTEN level. Our results provide new insights into skin aging-associated modification of the PI3K/NADPH oxidase signaling pathway and its relationship with a skin aging-dependent increase of ROS in human dermal fibroblasts.

  1. MiR-20a Induces Cell Radioresistance by Activating the PTEN/PI3K/Akt Signaling Pathway in Hepatocellular Carcinoma

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    Zhang, Yuqin [Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong Province (China); Zheng, Lin [Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guangdong Province (China); Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong Province (China); Ding, Yi [Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong Province (China); Li, Qi [Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong Province (China); Wang, Rong [Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong Province (China); Liu, Tongxin; Sun, Quanquan [Department of Radiation Oncology, Cancer Hospital, Hangzhou, Zhejiang Province (China); Yang, Hua [Department of Radiation Oncology, Nanhai Hospital, Southern Medical University, Guangzhou, Guangdong Province (China); Peng, Shunli [Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong Province (China); Wang, Wei, E-mail: wangwei9500@hotmail.com [Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong Province (China); Chen, Longhua, E-mail: chenlhsmu@126.com [Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong Province (China)

    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.

  2. VHL-deficient renal cancer cells gain resistance to mitochondria-activating apoptosis inducers by activating AKT through the IGF1R-PI3K pathway.

    Science.gov (United States)

    Yamaguchi, Ryuji; Harada, Hiroshi; Hirota, Kiichi

    2016-10-01

    We previously developed (2-deoxyglucose)-(ABT-263) combination therapy (2DG-ABT), which induces apoptosis by activating Bak in the mitochondria of highly glycolytic cells with varied genetic backgrounds. However, the rates of apoptosis induced by 2DG-ABT were lower in von Hippel-Lindau (VHL)-deficient cancer cells. The re-expression of VHL protein in these cells lowered IGF1R expression in a manner independent of oxygen concentration. Lowering IGF1R expression via small interfering RNA (siRNA) sensitized the cells to 2DG-ABT, suggesting that IGF1R interfered with the activation of apoptosis by the mitochondria. To determine which of the two pathways activated by IGF1R, the Ras-ERK pathway or the PI3K-AKT pathway, was involved in the impairment of mitochondria activation, the cells were treated with a specific inhibitor of either PI3K or ERK, and 2DG-ABT was added to activate the mitochondria. The apoptotic rates resulting from 2DG-ABT treatment were higher in the cells treated with the PI3K inhibitor, while the rates remained approximately the same in the cells treated with the ERK inhibitor. In 2DG-ABT-sensitive cells, a 4-h 2DG treatment caused the dissociation of Mcl-1 from Bak, while ABT treatment alone caused the dissociation of Bcl-xL from Bak without substantially reducing Mcl-1 levels. In 2DG-ABT-resistant cells, Mcl-1 dissociated from Bak only when AKT activity was inhibited during the 4-h 2DG treatment. Thus, in VHL-deficient cells, IGF1R activated AKT and stabilized the Bak-Mcl-1 complex, thereby conferring cell resistance to apoptosis.

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

    Directory of Open Access Journals (Sweden)

    Karin Hadas

    Full Text Available 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.

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

    Science.gov (United States)

    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.

  5. Neuroprotective effects of salidroside through PI3K/Akt pathway activation in Alzheimer’s disease models

    Directory of Open Access Journals (Sweden)

    Zhang B

    2016-04-01

    Full Text Available Bei Zhang,1,2 Ying Wang,1 Hui Li,1 Ran Xiong,1 Zongbo Zhao,1 Xingkun Chu,2 Qiongqiong Li,1 Suya Sun,1 Shengdi Chen1,2 1Department of Neurology, Institute of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People’s Republic of China; 2Laboratory of Neurodegenerative Diseases, The Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, People’s Republic of China Abstract: Alzheimer’s disease (AD is a devastating neurodegenerative disorder characterized by deposits of aggregated amyloid-β (Aβ peptide and neurofibrillary tangles in the brain parenchyma. Despite considerable research to elucidate the pathological mechanisms and identify therapeutic strategies for AD, effective treatments are still lacking. In the present study, we found that salidroside (Sal, a phenylpropanoid glycoside isolated from Rhodiola rosea L., can protect against Aβ-induced neurotoxicity in four transgenic Drosophila AD models. Both longevity and locomotor activity were improved in Sal-fed Drosophila. Sal also decreased Aβ levels and Aβ deposition in brain and ameliorated toxicity in Aβ-treated primary neuronal culture. The neuroprotective effect of Sal was associated with upregulated phosphatidylinositide 3-kinase (PI3K/Akt signaling. Our findings identify a compound that may possess potential therapeutic benefits for AD and other forms of neurodegeneration. Keywords: Alzheimer’s disease, amyloid-β, salidroside, Drosophila, neuroprotective effect

  6. PI3K/Akt signaling pathway involved in regulation of T lymphocyte activation and apoptosis mediated by CD3e

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    To study the expression and kinase activity of phosphatidylinositol 3′-kinase (PI3K) and protein kinase B (PKB or Akt) during activation and apoptosis of human Jurkat T lymphocytes (TJK) with stable expression of CD8e chimera fused human CD8a extracellular and transmembra-ne domains to intracellular domain of mouse CD3e, Western blot, kinase activities detection and immunoprecipitation were carried out. It was shown that Jurkat cells with expres-sion of wild type chimera CD8e died by apoptosis after con-tinuous stimulation of anti-CD8 monoclonal antibody. The expressions of PI3K and Akt, and the kinase activity of Akt remarkably increased during the process. However, this phenomenon did not occur in the Jurkat cells (T1JK) with expression of the mutant of CD8e chimera (Y170F), sug-gesting that PI3K/Akt signaling pathway is involved in acti-vation and apoptosis of T lymphocyte mediated by CD3e.

  7. Increased Osteogenic Differentiation of Periodontal Ligament Stem Cells on Polydopamine Film Occurs via Activation of Integrin and PI3K Signaling Pathways

    Directory of Open Access Journals (Sweden)

    Jeong Seok Lee

    2014-11-01

    Full Text Available Background/Aims: Mussel-inspired polydopamine (PDA is known to be an effective bioadhesive and bioactive material for controlling stem cell fate, which is important in stem cell-based regenerative medicine; however, the effect of PDA on osteogenic differentiation of periodontal ligament stem cells (PDLSCs is not fully understood. In this study, we investigated the osteoinductive effect of PDA on PDLSCs and examined how this phenomenon is encouraged. Methods: Osteogenic induction of PDLSCs was established by culturing cells on PDA film or on an uncoated polystyrene surface as a control. Osteogenic differentiation of PDLSCs was assessed by measurement of intracellular calcium levels and alkaline phosphatase (ALP activity as well as by evaluation of protein expression of osteocalcin (OCN, osterix (OSX, and runt-related transcription factor 2 (RUNX2. Results: The PDLSCs cultured on PDA film showed higher osteogenic activity than those on the control surface. Moreover, PDLSCs on PDA film expressed increased levels of the integrin adhesion receptors integrin α5 and β1 compared to control cells. Expression of one isoform of the intracellular signaling protein phosphatidylinositol-3-kinase (PI3K, p110γ, was increased in PDLSCs on PDA film in a PDA dose-dependent manner. This signaling protein was found to interact with integrin β1, demonstrating integrin-linked PI3K activation in response to PDA. Finally, the blockage of PI3K reduced the PDA-induced osteogenic activity of PDLSCs. Conclusion: our findings suggest that the bioadhesive PDA stimulates osteogenic differentiation of PDLSCs via activation of the integrin α5/β1 and PI3K signaling pathways.

  8. PI3K/Akt Signaling Pathway Activates the WNK-OSR1/SPAK-NCC Phosphorylation Cascade in Hyperinsulinemic db/db Mice

    Science.gov (United States)

    Nishida, Hidenori; Sohara, Eisei; Nomura, Naohiro; Chiga, Motoko; Alessi, Dario R; Rai, Tatemitsu; Sasaki, Sei; Uchida, Shinichi

    2013-01-01

    Metabolic syndrome patients have insulin resistance, which causes hyperinsulinemia, which in turn causes aberrant increased renal sodium reabsorption. The precise mechanisms underlying this greater salt-sensitivity of hyperinsulinemic patients remain unclear. Abnormal activation of the recently-identified WNK kinase-OSR1/SPAK kinases-NCC transporter phosphorylation cascade results in the salt-sensitive hypertension of pseudohypoaldosteronism type II. Here, we report a study of renal WNK-OSR1/SPAK-NCC cascade activation in the db/db mouse model of hyperinsulinemic metabolic syndrome. Thiazide sensitivity was increased, suggesting greater activity of NCC in db/db mice. In fact, increased phosphorylation of OSR1/SPAK and NCC was observed. In both SpakT243A/+ and Osr1T185A/+ knock-in db/db mice, which carry mutations that disrupt the signal from WNK kinases, increased phosphorylation of NCC and elevated blood pressure were completely corrected, indicating that phosphorylation of SPAK and OSR1 by WNK kinases is required for the increased activation and phosphorylation of NCC in this model. Renal phosphorylated Akt was increased in db/db mice, suggesting that increased NCC phosphorylation is regulated by the PI3K/Akt signaling cascade in the kidney in response to hyperinsulinemia. A PI3K inhibitor (NVP-BEZ235) corrected the increased OSR1/SPAK-NCC phosphorylation. Another more specific PI3K inhibitor (GDC-0941) and an Akt inhibitor (MK-2206) also inhibited increased NCC phosphorylation. These results indicate that the PI3K/Akt signaling pathway activates the WNK-OSR1/SPAK-NCC phosphorylation cascade in db/db mice. This mechanism may play a role in the pathogenesis of salt-sensitive hypertension in human hyperinsulinemic conditions such as the metabolic syndrome. PMID:22949526

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    Huawang Sun

    Full Text Available 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.

  11. Will PI3K pathway inhibitors be effective as single agents in patients with cancer?

    Science.gov (United States)

    Garrett, Joan T.; Chakrabarty, Anindita; Arteaga, Carlos L.

    2011-01-01

    The phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) axis regulates essential cellular functions including cell survival, proliferation, metabolism, migration, and angiogenesis. The PI3K pathway is activated in human cancers by mutation, amplification, and deletion of genes encoding components of this pathway. The critical role of PI3K in cancer has led to the development of drugs targeting the effector mechanisms of this signaling network. Recent studies have shown that inhibition at multiple levels of the PI3K pathway results in FOXO-dependent feedback reactivation of several receptor tyrosine kinases (RTKs) which, in turn, limit the sustained inhibition of this pathway and attenuates the action of therapeutic antagonists. This suggests that if used as single agents, PI3K pathway inhibitors may have limited clinical activity. We propose herein that to successfully target the output of the PI3K pathway in cancer cells, combination therapies that hinder these compensatory mechanisms should be used. Thus, combination therapies that target RTKs, PI3K, and mTOR activities may be required to maximize the clinical benefit derived from treatment with these inhibitors. PMID:22248929

  12. The therapeutic potential of targeting the PI3K pathway in pediatric brain tumors.

    Science.gov (United States)

    Rogers, Hazel A; Estranero, Jasper; Gudka, Keshni; Grundy, Richard G

    2017-01-10

    Central nervous system tumors are the most common cancer type in children and the leading cause of cancer related deaths. There is therefore a need to develop novel treatments. Large scale profiling studies have begun to identify alterations that could be targeted therapeutically, including the phosphoinositide 3-kinase (PI3K) signaling pathway, which is one of the most commonly activated pathways in cancer with many inhibitors under clinical development. PI3K signaling has been shown to be aberrantly activated in many pediatric CNS neoplasms. Pre-clinical analysis supports a role for PI3K signaling in the control of tumor growth, survival and migration as well as enhancing the cytotoxic effects of current treatments. Based on this evidence agents targeting PI3K signaling have begun to be tested in clinical trials of pediatric cancer patients. Overall, targeting the PI3K pathway presents as a promising strategy for the treatment of pediatric CNS tumors. In this review we examine the genetic alterations found in the PI3K pathway in pediatric CNS tumors and the pathological role it plays, as well as summarizing the current pre-clinical and clinical data supporting the use of PI3K pathway inhibitors for the treatment of these tumors.

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

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Deshun [Guangdong Key Laboratory of Pharmaceutical Bioactive Substances, Guangdong Pharmaceutical University, Guangzhou, Guangdong 510006 (China); Department of Pharmaceutical science, Guangdong Pharmaceutical University, Guangzhou, Guangdong (China); Liu, Bing [Department of Pharmaceutical science, Guangdong Pharmaceutical University, Guangzhou, Guangdong (China); Jin, Xiaobao [Guangdong Key Laboratory of Pharmaceutical Bioactive Substances, Guangdong Pharmaceutical University, Guangzhou, Guangdong 510006 (China); Zhu, Jiayong, E-mail: zhujiayong888@163.com [Guangdong Key Laboratory of Pharmaceutical Bioactive Substances, Guangdong Pharmaceutical University, Guangzhou, Guangdong 510006 (China)

    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.

  14. Salvianolic acid B protects against acetaminophen hepatotoxicity by inducing Nrf2 and phase II detoxification gene expression via activation of the PI3K and PKC signaling pathways.

    Science.gov (United States)

    Lin, Musen; Zhai, Xiaohan; Wang, Guangzhi; Tian, Xiaofeng; Gao, Dongyan; Shi, Lei; Wu, Hang; Fan, Qing; Peng, Jinyong; Liu, Kexin; Yao, Jihong

    2015-02-01

    Acetaminophen (APAP) is used drugs worldwide for treating pain and fever. However, APAP overdose is the principal cause of acute liver failure in Western countries. Salvianolic acid B (SalB), a major water-soluble compound extracted from Radix Salvia miltiorrhiza, has well-known antioxidant and anti-inflammatory actions. We aimed to evaluate the ability of SalB to protect against APAP-induced acute hepatotoxicity by inducing nuclear factor-erythroid-2-related factor 2 (Nrf2) expression. SalB pretreatment ameliorated acute liver injury caused by APAP, as indicated by blood aspartate transaminase levels and histological findings. Moreover, SalB pretreatment increased the expression of Nrf2, Heme oxygenase-1 (HO-1) and glutamate-l-cysteine ligase catalytic subunit (GCLC). Furthermore, the HO-1 inhibitor zinc protoporphyrin and the GCLC inhibitor buthionine sulfoximine reversed the protective effect of SalB. Additionally, siRNA-mediated depletion of Nrf2 reduced the induction of HO-1 and GCLC by SalB, and SalB pretreatment activated the phosphatidylinositol-3-kinase (PI3K) and protein kinase C (PKC) signaling pathways. Both inhibitors (PI3K and PKC) blocked the protective effect of SalB against APAP-induced cell death, abolishing the SalB-induced Nrf2 activation and decreasing HO-1 and GCLC expression. These results indicated that SalB induces Nrf2, HO-1 and GCLC expression via activation of the PI3K and PKC pathways, thereby protecting against APAP-induced liver injury.

  15. Rutin attenuates H2O2-induced oxidation damage and apoptosis in Leydig cells by activating PI3K/Akt signal pathways.

    Science.gov (United States)

    Sun, Jianhua; Wang, Heng; Liu, Bei; Shi, Wenhao; Shi, Juanzi; Zhang, Zhou; Xing, Junping

    2017-04-01

    Oxidative stress is a primary factor in the pathology of male infertility. The strong antioxidative capacity of rutin has been proven by numerous studies, but a protective role in the context of male reproduction remains to be elucidated. To explore the biological role of rutin in protecting male reproductive function and the potential underlying mechanism, H2O2-induced Leydig cells were used as a cell model of oxidation damage. Our findings showed that rutin at concentrations of 10, 20, and 40μmol/L remarkably increased cell survival rate of H2O2-induced Leydig cells to 70.1%, 86.8%, and 80.3% respectively. Next, rutin with concentrations of 10, 20, and 40μmol/L decreased reactive oxygen species (ROS) and malondialdehyde (MDA) levels but increased the levels of glutathione (GSH) and testosterone in H2O2-induced Leydig cells. The activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) were remarkably increased by rutin treatment with concentrations of 20 and 40μmol/L, but glutathione peroxidase (GSH-Px) activity was notably decreased. Moreover, rutin with concentrations of 10, 20, and 40μmol/L increased Bcl-2 protein levels but decreased protein levels of Bax and caspase-3. Furthermore, 20μmol/L rutin significantly abrogated the decrease in levels of phosphoinositide 3-kinase (PI3K) and phosphorylated serine/threonine kinase (p-AKT) induced by H2O2. Pretreatment with LY294002, a PI3K inhibitor, antagonized protective action of 20μmol/L rutin against H2O2-induced cell activities, intracellular oxidant, testosterone, antioxidant enzyme activities, and the apoptosis related protein expression. Taken together, these results suggest that rutin attenuates H2O2-induced oxidation damage and apoptosis in Leydig cells by activating PI3K/Akt signal pathways, providing a promising strategy to decrease oxidative stress associated with male infertility.

  16. Mild stretch activates cPLA2 in alveolar type II epithelial cells independently through the MEK/ERK and PI3K pathways.

    Science.gov (United States)

    Letsiou, Eleftheria; Kitsiouli, Ei; Nakos, George; Lekka, Marilena E

    2011-06-01

    Alveolar epithelial type II cells (AT II) in which lung surfactant synthesis and secretion take place, are subjected to low magnitude stretch during normal breathing. The aim of the study was to explore the effect of mild stretch on phospholipase A(2) (PLA(2)) activation, an enzyme known to be involved in surfactant secretion. In A549 cells (a model of AT II cells), we showed, using a fluorometric assay, that stretch triggers an increase of total PLA(2) activity. Western blot experiments revealed that the cytosolic isoform cPLA(2) is rapidly phosphorylated under stretch, in addition to a modest increase in cPLA(2) mRNA levels. Treatment of A549 cells with selective inhibitors of the MEK/ERK pathway significantly attenuated the stretch-induced cPLA(2) phosphorylation. A strong interaction of cPLA(2) and pERK enzymes was demonstrated by immunoprecipitation. We also found that inhibition of PI3K pathway attenuated cPLA(2) activation after stretch, without affecting pERK levels. Our results suggest that low magnitude stretch can induce cPLA(2) phosphorylation through the MEK/ERK and PI3K-Akt pathways, independently.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

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

    2014-01-01

    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 the present 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/cm2 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. PMID:25169110

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

    Science.gov (United States)

    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. © 2014 The American Society of Photobiology.

  20. Garlic attenuates cardiac oxidative stress via activation of PI3K/AKT/Nrf2-Keap1 pathway in fructose-fed diabetic rat.

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    Raju Padiya

    Full Text Available BACKGROUND: Cardiovascular complication due to diabetes has remained a major cause of death. There is an urgent need to intervene the cardiac complications in diabetes by nutritional or pharmacological agents. Thus the present study was designed to find out the effectiveness of garlic on cardiac complications in insulin-resistant diabetic rats. METHODS AND RESULTS: SD rats were fed high fructose (65% diet alone or along with raw garlic homogenate (250 mg/kg/day or nutrient-matched (65% corn starch control diet for 8 weeks. Fructose-fed diabetic rats showed cardiac hypertrophy, increased NFkB activity and increased oxidative stress. Administration of garlic significantly decreased (p<0.05 cardiac hypertrophy, NFkB activity and oxidative stress. Although we did not observe any changes in myocardial catalase, GSH and GPx in diabetic heart, garlic administration showed significant (p<0.05 increase in all three antioxidant/enzymes levels. Increased endogenous antioxidant enzymes and gene expression in garlic treated diabetic heart are associated with higher protein expression of Nrf2. Increased myocardial H2S levels, activation of PI3K/Akt pathway and decreased Keap levels in fructose-fed heart after garlic administration might be responsible for higher Nrf2 levels. CONCLUSION: Our study demonstrates that raw garlic homogenate is effective in reducing cardiac hypertrophy and fructose-induced myocardial oxidative stress through PI3K/AKT/Nrf2-Keap1 dependent pathway.

  1. Astaxanthin reduces isoflurane-induced neuroapoptosis via the PI3K/Akt pathway.

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    Wang, Chun-Mei; Cai, Xiao-Lan; Wen, Qing-Ping

    2016-05-01

    Astaxanthin is an oxygen-containing derivative of carotenoids that effectively suppresses reactive oxygen and has nutritional and medicinal value. The mechanisms underlying the effects of astaxanthin on isoflurane‑induced neuroapoptosis remain to be fully understood. The present study was conducted to evaluate the protective effect of astaxanthin to reduce isoflurane‑induced neuroapoptosis and to investigate the underlying mechanisms. The results demonstrated that isoflurane induced brain damage, increased caspase‑3 activity and suppressed the phosphatidylinositol 3‑kinase (PI3K)/protein kinase B (Akt) signaling pathway in an in vivo model. However, treatment with astaxanthin significantly inhibited brain damage, suppressed caspase‑3 activity and upregulated the PI3K/Akt pathway in the isoflurane‑induced rats. Furthermore, isoflurane suppressed cell growth, induced cell apoptosis, enhanced caspase‑3 activity and downregulated the PI3K/Akt pathway in organotypic hippocampal slice culture. Administration of astaxanthin significantly promoted cell growth, reduced cell apoptosis and caspase‑3 activity, and upregulated the PI3K/Akt pathway and isoflurane‑induced neuroapoptosis. The present study demonstrated that downregulation of the PI3K/Akt pathway reduced the effect of astaxanthin to protect against isoflurane‑induced neuroapoptosis in the in vitro model. The results of the current study suggested that the protective effect of astaxanthin reduces the isoflurane-induced neuroapoptosis via activation of the PI3K/Akt signaling pathway.

  2. A novel formula Sang-Tong-Jian improves glycometabolism and ameliorates insulin resistance by activating PI3K/AKT pathway in type 2 diabetic KKAy mice.

    Science.gov (United States)

    Kuai, Meiyu; Li, Yu; Sun, Xin; Ma, Zhi; Lin, Chao; Jing, Yi; Lu, Ying; Chen, Qi; Wu, Xiang; Kong, Xueyun; Bian, Huimin

    2016-12-01

    translocation and phosphorylation of IRS1, p85-PI3K and AKT were significantly increased by STJ treatments. Our results indicated that STJ ameliorated glycometabolism and insulin resistance in KKAy mice, which might be due to activation of PI3K/AKT pathway. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  3. Silica nanoparticles induce multinucleation through activation of PI3K/Akt/GSK-3β pathway and downregulation of chromosomal passenger proteins in L-02 cells

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    Geng, Weijia; Li, Yang; Yu, Yongbo; Yu, Yang; Duan, Junchao; Jiang, Lizhen; Li, Qiuling; Sun, Zhiwei

    2016-04-01

    Silica nanoparticles (SNPs) are applicable in various fields due to their unique physicochemical characteristics. However, concerns over their potential adverse effects have been raised. In our previous studies, we reported that SNPs could induce abnormal high incidence of multinucleation. The aim of this study is to further investigate the mechanisms of multinucleation induced by SNPs (68 nm) in human normal liver L-02 cells (L-02 cells). In order to determine the cytotoxicity of SNPs, MTT assay was performed, and the cell viability was decreased in a dose-dependent manner. The intracellular reactive oxygen species (ROS) detected by flow cytometry and multinucleation observed by Giemsa stain showed that ROS generation and rate of multinucleated cells increased after SNPs exposure. N-acetyl-cysteine (NAC), a glutathione precursor against SNP-induced toxicity, was used as a ROS inhibitor to elucidate the relationship between ROS and multinucleation. The presence of NAC resulted in inhibition of both ROS generation and rate of multinucleation. Moreover, Western blot analysis showed that the protein levels of Cdc20, Aurora B, and Survivin were down-regulated, and the PI3K/Akt/GSK-3β pathway was activated by SNPs. In conclusion, our findings strongly suggested that multinucleation induced by SNPs was related to PI3K/Akt/GSK-3β signal pathway activation and downregulation of G2/M phase-related protein and chromosomal passenger proteins.

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

    Science.gov (United States)

    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.

  5. Protection afforded by quercetin against H2O2-induced apoptosis on PC12 cells via activating PI3K/Akt signal pathway.

    Science.gov (United States)

    Chen, Liang; Sun, Lejin; Liu, Zhene; Wang, Hongxia; Xu, Cunli

    2016-01-01

    Cell damage and apoptosis induced by oxidative stress have been involved in various neurodegenerative diseases. This study aims to explore the neuro-protective effects of quercetin on PC12 cells apoptosis induced by hydrogen peroxide (H(2)O(2)) and the underlying mechanisms. The cell viability was detected, as well as the production of reactive oxygen species (ROS), lactate dehydrogenase (LDH) leakage, and the activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and malondialdehyde (MDA) of the cells in control, H(2)O(2) and quercetin groups. It finally turned out that quercetin might protect PC12 cells against the negative effect of H(2)O(2) by decreasing of LDH release, ROS concentration and MDA level and regaining the GSH-Px and SOD activities. To investigate the mechanism, LY294002 was introduced, the phosphatidylinositol-3-kinase (PI3K) inhibitor. Bax/Bcl-2 ratio and Akt phosphorylation (p-Akt) were examined by Western blot analysis. The data showed that LY294002 almost had the same effects with H(2)O(2), which was also significantly reversed by quercetin could enhance Bax/Bcl-2 ratio and adjust the p-Akt expression, which indicated quercetin might protect PC12 cells against the negative effect of H(2)O(2) via activating the PI3K/Akt signal pathway.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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. Targeting the PI3K/Akt pathway in prostate cancer: challenges and opportunities (review).

    Science.gov (United States)

    Toren, Paul; Zoubeidi, Amina

    2014-11-01

    The PI3K/Akt pathway is an actively pursued therapeutic target in oncology. In prostate cancer, the activation of this pathway appears to be characteristic of many aggressive prostate cancers. Further, activation of the PI3K/Akt pathway is more frequently observed as prostate cancer progresses toward a resistant, metastatic disease. Signalling from this pathway activates numerous survival, growth, metabolic and metastatic functions characteristic of aggressive cancer. Biomarkers of this pathway have correlated activation of this pathway to high grade disease and higher risk of disease progression. Therefore there is significant interest in developing effective strategies to target this pathway in prostate cancer. In this review, we discuss the pre-clinical and clinical data relevant to targeting of the PI3K/Akt pathway in prostate cancer. In particular, we review the rationale and relevance of co-targeting approaches against the PI3K/Akt pathway. It is anticipated that through an improved understanding of the biology of the PI3K/Akt pathway in prostate cancer, relevant biomarkers and rationale combination therapies will optimize targeting of this pathway to improve outcomes among patients with aggressive prostate cancer.

  9. Protease-activated receptor-2 promotes kidney tubular epithelial inflammation by inhibiting autophagy via the PI3K/Akt/mTOR signalling pathway.

    Science.gov (United States)

    Du, Chunyang; Zhang, Tao; Xiao, Xia; Shi, Yonghong; Duan, Huijun; Ren, Yunzhuo

    2017-08-02

    Protease-activated receptor-2 (PAR2), which belongs to a specific class of the G-protein-coupled receptors, is central to several inflammation processes. However, the precise molecular mechanism involved remains undefined. Autophagy has been previously shown to affect inflammation. In the present study, we examine the effect of PAR2 on kidney tubular epithelial autophagy and on autophagy-related inflammation and reveal the underlying mechanism involved. Autophagic activity and levels of autophagic marker LC3 were examined in human kidney tubular epithelial cells with PAR2 knockdown or overexpression. We administered the mammalian target of rapamycin (mTOR) inhibitor (rapamycin) or activator (MHY1485) to investigate the function of the phosphoinositide 3-kinase (PI3K)/Akt/mTOR pathway. We also used transforming growth factor-β1 (TGF-β1)-induced HK-2 cell inflammation models to investigate the role of PAR2-associated autophagy in kidney tubular epithelial inflammation. PAR2 antagonist and rapamycin were administered to mice after unilateral ureteral obstruction to detect the correlations between PAR2, autophagy, and inflammation. Our results show that PAR2 overexpression in HK-2 cells led to a greater reduction in autophagy via the PI3K/Akt/mTOR pathway activation and induces autophagy-related inflammation. Meanwhile, a knockdown of PAR2 via PAR2 RNAi transfection greatly increased autophagy and alleviated autophagy-associated inflammation. In unilateral ureteral obstruction (UUO) kidneys, PAR2 antagonist treatment greatly attenuated renal inflammation and interstitial injury by enhancing autophagy. Moreover, inhibition of mTOR, rapa, markedly increased autophagy and inhibited the UUO-induced inflammation. We conclude that PAR2 induces kidney tubular epithelial inflammation by inhibiting autophagy via the PI3K/Akt/mTOR signalling pathway. Our results are suggestive that PAR2 inhibition may play a role in the treatment of diseases with increased inflammatory

  10. The PI3K Pathway: Background and Treatment Approaches.

    Science.gov (United States)

    Lux, Michael P; Fasching, Peter A; Schrauder, Michael G; Hein, Alexander; Jud, Sebastian M; Rauh, Claudia; Beckmann, Matthias W

    2016-12-01

    Two-thirds of all breast cancer patients with metastases have a hormone receptor (HR)-positive/human epidermal growth factor receptor 2 (HER2)-negative subtype. Endocrine therapy is the treatment of choice in these patients since in addition to its effectiveness it can also maintain the patients' quality of life over a longer term. However, 44-62% of postmenopausal patients with metastatic breast carcinoma have primary tamoxifen resistance. After 3-5 years, 30-40% of the patients receiving tamoxifen treatment develop secondary resistance. Understanding the way in which resistance develops is therefore essential for developing treatment approaches that can prevent or reverse endocrine resistance. The phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling pathway plays a central role here. As a result of the numerous interactions involved, complex issues arise that need to be taken into account in the development and use of therapeutic agents. In addition, this signaling pathway is the one that most frequently undergoes mutations in breast cancer. The prognostic and predictive significance of individual mutations has not yet been fully explained, but it might provide a basis for patient selection in clinical studies. Initial research results on the use of PI3K inhibitors suggest that this may be a highly promising therapeutic approach, with an acceptable side effect profile.

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

    Directory of Open Access Journals (Sweden)

    Wei Yang

    2013-12-01

    Full Text Available 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.

  12. Oncogenic BRAF fusions in mucosal melanomas activate the MAPK pathway and are sensitive to MEK/PI3K inhibition or MEK/CDK4/6 inhibition.

    Science.gov (United States)

    Kim, H S; Jung, M; Kang, H N; Kim, H; Park, C-W; Kim, S-M; Shin, S J; Kim, S H; Kim, S G; Kim, E K; Yun, M R; Zheng, Z; Chung, K Y; Greenbowe, J; Ali, S M; Kim, T-M; Cho, B C

    2017-01-16

    Despite remarkable progress in cutaneous melanoma genomic profiling, the mutational landscape of primary mucosal melanomas (PMM) remains unclear. Forty-six PMMs underwent targeted exome sequencing of 111 cancer-associated genes. Seventy-six somatic nonsynonymous mutations in 42 genes were observed, and recurrent mutations were noted on eight genes, including TP53 (13%), NRAS (13%), SNX31 (9%), NF1 (9%), KIT (7%) and APC (7%). Mitogen-activated protein kinase (MAPK; 37%), cell cycle (20%) and phosphatidylinositol 3-kinase (PI3K)-mTOR (15%) pathways were frequently mutated. We biologically characterized a novel ZNF767-BRAF fusion found in a vemurafenib-refractory respiratory tract PMM, from which cell line harboring ZNF767-BRAF fusion were established for further molecular analyses. In an independent data set, NFIC-BRAF fusion was identified in an oral PMM case and TMEM178B-BRAF fusion and DGKI-BRAF fusion were identified in two malignant melanomas with a low mutational burden (number of mutation per megabase, 0.8 and 4, respectively). Subsequent analyses revealed that the ZNF767-BRAF fusion protein promotes RAF dimerization and activation of the MAPK pathway. We next tested the in vitro and in vivo efficacy of vemurafenib, trametinib, BKM120 or LEE011 alone and in combination. Trametinib effectively inhibited tumor cell growth in vitro, but the combination of trametinib and BKM120 or LEE011 yielded more than additive anti-tumor effects both in vitro and in vivo in a melanoma cells harboring the BRAF fusion. In conclusion, BRAF fusions define a new molecular subset of PMM that can be targeted therapeutically by the combination of a MEK inhibitor with PI3K or cyclin-dependent kinase 4/6 inhibitors.Oncogene advance online publication,16 January 2017; doi:10.1038/onc.2016.486.

  13. Salidroside ameliorates insulin resistance through activation of a mitochondria-associated AMPK/PI3K/Akt/GSK3β pathway.

    Science.gov (United States)

    Zheng, Tao; Yang, Xiaoyan; Wu, Dan; Xing, Shasha; Bian, Fang; Li, Wenjing; Chi, Jiangyang; Bai, Xiangli; Wu, Guangjie; Chen, Xiaoqian; Zhang, Yonghui; Jin, Si

    2015-07-01

    Recent reports have suggested that salidroside could protect cardiomyocytes from oxidative injury and stimulate glucose uptake in skeletal muscle cells by activating AMP-activated protein kinase (AMPK). The aim of this study was to evaluate the therapeutic effects of salidroside on diabetic mice and to explore the underlying mechanisms. The therapeutic effects of salidroside on type 2 diabetes were investigated. Increasing doses of salidroside (25, 50 and 100 mg·kg(-1) ·day(-1)) were administered p.o. to db/db mice for 8 weeks. Biochemical analysis and histopathological examinations were conducted to evaluate the therapeutic effects of salidroside. Primary cultured mouse hepatocytes were used to further explore the underlying mechanisms in vitro. Salidroside dramatically reduced blood glucose and serum insulin levels and alleviated insulin resistance. Hypolipidaemic effects and amelioration of liver steatosis were observed after salidroside administration. In vitro, salidroside dose-dependently induced an increase in the phosphorylations of AMPK and PI3K/Akt, as well as glycogen synthase kinase 3β (GSK3β) in hepatocytes. Furthermore, salidroside-stimulated AMPK activation was found to suppress the expression of PEPCK and glucose-6-phosphatase. Salidroside-induced AMPK activation also resulted in phosphorylation of acetyl CoA carboxylase, which can reduce lipid accumulation in peripheral tissues. In isolated mitochondria, salidroside inhibited respiratory chain complex I and disturbed oxidation/phosphorylation coupling and moderately depolarized the mitochondrial membrane potential, resulting in a transient increase in the AMP/ATP ratio. Salidroside exerts an antidiabetic effect by improving the cellular metabolic flux through the activation of a mitochondria-related AMPK/PI3K/Akt/GSK3β pathway. © 2015 The British Pharmacological Society.

  14. Rapamycin Prevents cyclophosphamide-induced Over-activation of Primordial Follicle pool through PI3K/Akt/mTOR Signaling Pathway in vivo.

    Science.gov (United States)

    Zhou, Linyan; Xie, Yanqiu; Li, Song; Liang, Yihua; Qiu, Qi; Lin, Haiyan; Zhang, Qingxue

    2017-08-16

    Primordial follicular depletion has thought to be a common adverse effect of chemotherapy especially for female of reproductive age. The study aimed to evaluate the protective effect of rapamycin on the primordial follicles and its potential mechanism for patients receiving chemotherapy. 8-week old BALB/c female mice were randomly assigned into four groups (control; rapamycin; cyclophosphamide; and rapamycin combined with cyclophosphamide). Hematoxylin staining, immunohistochemical, TUNEL, western blotting and ELISA were employed to assess inter-group differences using Student's t-test and Mann-Whitney test. Cyclophosphamide depleted the follicular reserve and induced the phosphorylation of the key proteins of PI3K/Akt/mTOR pathway in mice in a dose-dependent manner. Co-treatment with rapamycin significantly reduced primordial follicle loss at all cyclophosphamide dose groups and prevent the follicle growth wave caused by cyclophosphamide treatment (P primordial follicles in all groups and fewer apoptosis in large growing follicles were observed in ovaries from rapamycin + cyclophosphamide group compared to that received cyclophosphamide alone. Serum anti-Müllerian hormone (AMH) was significantly reduced in cyclophosphamide alone group, in contrast to the normal level in rapamycin + cyclophosphamide group. Compared to p-Akt/Akt and p-mtor/mtor, p-rps6/rps6 was significantly decreased in rapamycin + cyclophosphamide group (P primordial follicle activation induced by cyclophosphamide through PI3K/Akt/mTOR signaling pathway and thus plays a role in preserving the follicle pool. These results suggest that rapamycin may be an effective protection for ovarian function during chemotherapy, which means a new nonsurgical application for protection of ovarian reserve and prevention of POF.

  15. HO-1 attenuates hippocampal neurons injury via the activation of BDNF-TrkB-PI3K/Akt signaling pathway in stroke.

    Science.gov (United States)

    Qi, Dashi; Ouyang, Changjie; Wang, Yulan; Zhang, Shichun; Ma, Xijuan; Song, YuanJian; Yu, HongLi; Tang, Jiali; Fu, Wei; Sheng, Lei; Yang, Lihua; Wang, Mei; Zhang, Weihao; Miao, Lei; Li, Tengteng; Huang, Xiaojing; Dong, Hongyan

    2014-08-19

    Although recent studies have found that HO-1 plays an important role in neuronal survival, little is known about the precise mechanisms occurring during cerebral ischemia/reperfusion (I/R). Therefore, the aim of this study was to investigate the neuroprotective mechanisms of HO-1 against ischemic brain injury induced by cerebral I/R and to explore whether the BDNF-TrkB-PI3K/Akt signaling pathway contributed to the protection provided by HO-1. Over-expressed HO-1 plasmids were employed to induce the overexpression of HO-1 through hippocampi CA1 injection 5 days before the cerebral I/R animal model was induced by four-vessel occlusion for 15 min transient ischemia and followed by reperfusion in Sprague-Dawley rats. Immunoblotting was carried out to examine the expression of the related proteins, and HE-staining was used to detect the percentage of living neurons in the hippocampal CA1 region. The results showed that over-expressed HO-1 could significantly protect neurons against cerebral I/R. Furthermore, the protein expression of BDNF, TrkB and p-Akt also increased in the rats treated with over-expressed HO-1 plasmids. However, treatment with tropomyosin receptor kinase B (TrkB) receptor antagonist (K252a) reversed the HO-1-induced increase in BDNF and p-Akt protein levels and decreased the level of cleaved caspase-3 protein in I/R rats. In summary, our results imply that HO-1 can decrease cell apoptosis in the I/R rat brain and that the mechanism may be related to the activation of the BDNF-TrkB-PI3K/Akt signaling pathway.

  16. The proto-oncogene c-src is involved in primordial follicle activation through the PI3K, PKC and MAPK signaling pathways.

    Science.gov (United States)

    Du, Xiao-Yu; Huang, Jian; Xu, Liang-Quan; Tang, Dan-Feng; Wu, Lei; Zhang, Li-Xia; Pan, Xiao-Ling; Chen, Wei-Yun; Zheng, Li-Ping; Zheng, Yue-Hui

    2012-08-20

    C-src is an evolutionarily conserved proto-oncogene that regulates cell proliferation, differentiation and apoptosis. In our previous studies, we have reported that another proto-oncogene, c-erbB2, plays an important role in primordial follicle activation and development. We also found that c-src was expressed in mammalian ovaries, but its functions in primordial follicle activation remain unclear. The objective of this study is to investigate the role and mechanism of c-src during the growth of primordial follicles. Ovaries from 2-day-old rats were cultured in vitro for 8 days. Three c-src-targeting and one negative control siRNA were designed and used in the present study. PCR, Western blotting and primordial follicle development were assessed for the silencing efficiency of the lentivirus c-src siRNA and its effect on primordial follicle onset. The expression of c-src mRNA and protein in primordial follicle growth were examined using the PCR method and immunohistochemical staining. Furthermore, the MAPK inhibitor PD98059, the PKC inhibitor Calphostin and the PI3K inhibitor LY294002 were used to explore the possible signaling pathways of c-src in primordial folliculogenesis. The results showed that Src protein was distributed in the ooplasmic membrane and the granulosa cell membrane in the primordial follicles, and c-src expression level increased with the growth of primordial follicle. The c-src -targeting lentivirus siRNAs had a silencing effect on c-src mRNA and protein expression. Eight days after transfection of rat ovaries with c-src siRNA, the GFP fluorescence in frozen ovarian sections was clearly discernible under a fluorescence microscope, and its relative expression level was 5-fold higher than that in the control group. Furthermore, the c-src-targeting lentivirus siRNAs lowered its relative expression level 1.96 times. We also found that the development of cultured primordial follicles was completely arrested after c-src siRNA knockdown of c

  17. Direct association of heat shock protein 20 (HSPB6 with phosphoinositide 3-kinase (PI3K in human hepatocellular carcinoma: regulation of the PI3K activity.

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    Rie Matsushima-Nishiwaki

    Full Text Available HSP20 (HSPB6, one of small heat shock proteins (HSPs, is constitutively expressed in various tissues and has several functions. We previously reported that the expression levels of HSP20 in human hepatocellular carcinoma (HCC cells inversely correlated with the progression of HCC, and that HSP20 suppresses the growth of HCC cells via the AKT and mitogen-activated protein kinase signaling pathways. However, the exact mechanism underlying the effect of HSP20 on the regulation of these signaling pathways remains to be elucidated. To clarify the details of this effect in HCC, we explored the direct targets of HSP20 in HCC using human HCC-derived HuH7 cells with HSP20 overexpression. HSP20 proteins in the HuH7 cells were coimmunoprecipitated with the p85 regulatory subunit and p110 catalytic subunit of phosphoinositide 3-kinase (PI3K, an upstream kinase of AKT. Although HSP20 overexpression in HCC cells failed to affect the expression levels of PI3K, the activity of PI3K in the unstimulated cells and even in the transforming growth factor-α stimulated cells were downregulated by HSP20 overexpression. The association of HSP20 with PI3K was also observed in human HCC tissues in vivo. These findings strongly suggest that HSP20 directly associates with PI3K and suppresses its activity in HCC, resulting in the inhibition of the AKT pathway, and subsequently decreasing the growth of HCC.

  18. Dual inhibition of the PI3K/AKT/mTOR pathway suppresses the growth of leiomyosarcomas but leads to ERK activation through mTORC2: biological and clinical implications.

    Science.gov (United States)

    Fourneaux, Benjamin; Chaire, Vanessa; Lucchesi, Carlo; Karanian, Marie; Pineau, Raphael; Laroche-Clary, Audrey; Italiano, Antoine

    2017-01-31

    The PI3K/AKT/mTOR pathway plays a crucial role in the development of leiomyosarcomas (LMSs). In this study, we tested the efficacy of dual PI3K/mTOR (BEZ235), PI3K (BKM120) and mTOR (everolimus) inhibitors in three human LMS cell lines. In vitro and in vivo studies using LMS cell lines showed that BEZ235 has a significantly higher anti-tumor effect than either BKM120 or everolimus, resulting in a greater reduction in tumor growth and more pronounced inhibitory effects on mitotic activity and PI3K/AKT/mTOR signaling. Strikingly, BEZ235 but neither BKM120 nor everolimus markedly enhanced the ERK pathway. This effect was reproduced by the combination of BKM120 and everolimus, suggesting the involvement of mTORC2 via a PI3K-independent mechanism. Silencing of RICTOR in LMS cells confirmed the role of mTORC2 in the regulation of ERK activity. Combined treatment with BEZ235 and GSK1120212, a potent MEK inhibitor, resulted in synergistic growth inhibition and apoptosis induction in vitro and in vivo. These findings document for the first time that dual PI3K/mTOR inhibition in leiomyosarcomas suppress a negative feedback loop mediated by mTORC2, leading to enhanced ERK pathway activity. Thus, combining a dual PI3K/mTOR inhibitor with MEK inhibitors may be a relevant approach to increase anti-tumor activity and prevent drug resistance in patients with LMS.

  19. Paeonia lactiflora Pall. protects against ANIT-induced cholestasis by activating Nrf2 via PI3K/Akt signaling pathway

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    Ma X

    2015-09-01

    Full Text Available Xiao Ma,1,2 Yan-ling Zhao,2 Yun Zhu,3 Zhe Chen,1,2 Jia-bo Wang,4 Rui-yu Li,1,4 Chang Chen,1,2 Shi-zhang Wei,1,2 Jian-yu Li,3 Bing Liu,5 Rui-lin Wang,3 Yong-gang Li,3 Li-fu Wang,3 Xiao-he Xiao4 1Pharmacy College, Chengdu University of Traditional Chinese Medicine, Chengdu, People’s Republic of China; 2Department of Pharmacy, 302 Military Hospital of People’s Liberation Army, Beijing, People’s Republic of China; 3Department of Integrative Medical Center, 302 Military Hospital of People’s Liberation Army, Beijing, People’s Republic of China; 4China Military Institute of Chinese Medicine, 302 Military Hospital of People’s Liberation Army, Beijing, People’s Republic of China; 5School of Chinese Medicine, The University of Hong Kong, Hong Kong Background: Paeonia lactiflora Pall. (PLP, a traditional Chinese herbal medicine, has been used for hepatic disease treatment over thousands of years. In our previous study, PLP was shown to demonstrate therapeutic effect on hepatitis with severe cholestasis. The aim of this study was to evaluate the antioxidative effect of PLP on alpha-naphthylisothiocyanate (ANIT-induced cholestasis by activating NF-E2-related factor 2 (Nrf2 via phosphatidylinositol 3-kinase (PI3K/Akt signaling pathway. Materials and methods: Liquid chromatography-mass spectrometry (LC-MS was performed to identify the main compounds present in PLP. The mechanism of action of PLP and its therapeutic effect on cholestasis, induced by ANIT, were further investigated. Serum indices such as total bilirubin (TBIL, direct bilirubin (DBIL, aspartate aminotransferase (AST, alanine aminotransferase (ALT, alkaline phosphatase (ALP, γ-glutamyl transpeptidase (γ-GT, and total bile acid (TBA were measured, and histopathology of liver was also performed to determine the efficacy of treatment with PLP. Moreover, in order to illustrate the underlying signaling pathway, liver glutathione (GSH content and mRNA or protein levels of glutamate

  20. Activation of PI3K/AKT and MAPK pathway through a PDGFRβ-dependent feedback loop is involved in rapamycin resistance in hepatocellular carcinoma.

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    Quan-Lin Li

    Full Text Available BACKGROUND: Rapamycin is an attractive approach for the treatment and prevention of HCC recurrence after liver transplantation. However, the objective response rates of rapamycin achieved with single-agent therapy were modest, supporting that rapamycin resistance is a frequently observed characteristic of many cancers. Some studies have been devoted to understanding the mechanisms of rapamycin resistance, however, the mechanisms are cell-type-dependent and studies on rapamycin resistance in HCC are extremely limited. METHODOLOGY/PRINCIPAL FINDINGS: The anti-tumor sensitivity of rapamycin was modest in vitro and in vivo. In both human and rat HCC cells, rapamycin up-regulated the expression and phosphorylation of PDGFRβ in a time and dose-dependent manner as assessed by RT-PCR and western blot analysis. Using siRNA mediated knockdown of PDGFRβ, we confirmed that subsequent activation of AKT and ERK was PDGFRβ-dependent and compromised the anti-tumor activity of rapamycin. Then, blockade of this PDGFRβ-dependent feedback loop by sorafenib enhanced the anti-tumor sensitivity of rapamycin in vitro and in an immunocompetent orthotopic rat model of HCC. CONCLUSIONS: Activation of PI3K/AKT and MAPK pathway through a PDGFRβ-dependent feedback loop compromises the anti-tumor activity of rapamycin in HCC, and blockade of this feedback loop by sorafenib is an attractive approach to improve the anti-tumor effect of rapamycin, particularly in preventing or treating HCC recurrence after liver transplantation.

  1. Epidermal growth factor-like domain 7 promotes migration and invasion of human trophoblast cells through activation of MAPK, PI3K and NOTCH signaling pathways.

    Science.gov (United States)

    Massimiani, M; Vecchione, L; Piccirilli, D; Spitalieri, P; Amati, F; Salvi, S; Ferrazzani, S; Stuhlmann, H; Campagnolo, L

    2015-05-01

    Epidermal growth factor-like domain 7 (Egfl7) is a gene that encodes a partially secreted protein and whose expression is largely restricted to the endothelia. We recently reported that EGFL7 is also expressed by trophoblast cells in mouse and human placentas. Here, we investigated the molecular pathways that are regulated by EGFL7 in trophoblast cells. Stable EGFL7 overexpression in a Jeg3 human choriocarcinoma cell line resulted in significantly increased cell migration and invasiveness, while cell proliferation was unaffected. Analysis of mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K) pathways showed that EGFL7 promotes Jeg3 cell motility by activating both pathways. We show that EGFL7 activates the epidermal growth factor receptor (EGFR) in Jeg3 cells, resulting in downstream activation of extracellular regulated kinases (ERKs). In addition, we provide evidence that EGFL7-triggered migration of Jeg3 cells involves activation of NOTCH signaling. EGFL7 and NOTCH1 are co-expressed in Jeg3 cells, and blocking of NOTCH activation abrogates enhanced migration of Jeg3 cells overexpressing EGFL7. We also demonstrate that signaling through EGFR and NOTCH converged to mediate EGFL7 effects. Reduction of endogenous EGFL7 expression in Jeg3 cells significantly decreased cell migration. We further confirmed that EGFL7 stimulates cell migration by using primary human first trimester trophoblast (PTB) cells overexpressing EGFL7. In conclusion, our data suggest that in trophoblast cells, EGFL7 regulates cell migration and invasion by activating multiple signaling pathways. Our results provide a possible explanation for the correlation between reduced expression of EGFL7 and inadequate trophoblast invasion observed in placentopathies.

  2. Anti-fibrotic actions of interleukin-10 against hypertrophic scarring by activation of PI3K/AKT and STAT3 signaling pathways in scar-forming fibroblasts.

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    Jihong Shi

    inhibits fibrosis by activating AKT and STAT3 phosphorylation downstream of the IL-10 receptor, and by facilitating crosstalk between the PI3K/AKT and STAT3 signal transduction pathways.

  3. REC8 is a novel tumor suppressor gene epigenetically robustly targeted by the PI3K pathway in thyroid cancer.

    Science.gov (United States)

    Liu, Dingxie; Shen, Xiaopei; Zhu, Guangwu; Xing, Mingzhao

    2015-11-17

    The role of the PI3K pathway in human cancer has been well established, but much of its molecular mechanism, particularly the epigenetic aspect, remains to be defined. We hypothesized that aberrant methylation and hence altered expression of certain unknown important genes induced by the genetically activated PI3K pathway signaling is a major epigenetic mechanism in human tumorigenesis. Through a genome-wide search for such genes that were epigenetically controlled by the PI3K pathway in thyroid cancer cells, we found a wide range of genes with broad functions epigenetically targeted by the PI3K pathway. The most prominent among these genes was REC8, classically known as a meiotic-specific gene, which we found to be robustly down-regulated by the PI3K pathway through hypermethylation. REC8 hypermethylation was strongly associated with genetic alterations and activities of the PI3K pathway in thyroid cancer cell lines, thyroid cancer tumors, and some other human cancers; it was also associated with poor clinicopathological outcomes of thyroid cancer, including advanced disease stages and patient mortality. Demethylating the hypermethylated REC8 gene restored its expression in thyroid cancer cells in which the PI3K pathway was genetically over-activated and induced expression of REC8 protein inhibited the proliferation and colony formation of these cells. These findings are consistent with REC8 being a novel major bona fide tumor suppressor gene and a robust epigenetic target of the PI3K pathway. Aberrant inactivation of REC8 through hypermethylation by the PI3K pathway may represent an important mechanism mediating the oncogenic functions of the PI3K pathway.

  4. MicroRNA-21 promotes bone mesenchymal stem cells migration in vitro by activating PI3K/Akt/MMPs pathway.

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    Lv, Chen; Yang, Shengwu; Chen, Xin; Zhu, Xiongbai; Lin, Wenjun; Wang, Lu; Huang, Zhengxiang; Wang, Mingyue; Tu, Guanjun

    2017-08-24

    MicroRNA-21 (miR-21) contributes to anti-apoptosis in bone marrow mesenchymal stem cells (BMSC), but its role in the migration of BMSCs remains vague. The aim of this study was to determine the possible effect of miR-21 on regulating BMSCs directional migration and the expression of MMP-2/MMP-9 in BMSCs in vitro. BMSCs were successfully infected with miR-21-up lentivirus. Cell migration using Transwell assay indicated that upregulated expression of miR-21 could significantly promote BMSCs migration. Western blot analysis indicated that miR-21 significantly upregulated the expression of MMP-2 and MMP-9, which were related to metastasis-associated genes. GM6001, the specific MMPs inhibitor, abrogated the upregulated expression of MMP-2/MMP-9 and abolished the positive effect of miR-21 on promoting BMSCs migration. Meanwhile, miR-21 significantly enhanced Akt phosphorylation, as measured by Western blot analysis. LY294002, an inhibitor of Akt activation, abrogated the phosphorylation of Akt and abolished the positive effect of miR-21 on promoting BMSCs migration and upregulating MMP-2/MMP-9 expression. These results suggest that miR-21 contributes to BMSCs migration by upregulating MMP-2/MMP-9, potentially via the PI3K/Akt pathway. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    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.

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

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    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.

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

    KAUST Repository

    Cheung, Lydia W T

    2015-07-29

    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 monomerdimers regulates the PI3K pathway and disrupting this equilibrium could lead to disease development. © Cheung et al.

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

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    Zheng, Zhen; Li, Zhiliang; Chen, Song; Pan, Jieyi; Ma, Xiaochun, E-mail: zjoever@gmail.com

    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.

  9. Molecular targets for cancer therapy in the PI3K/AKT/mTOR pathway.

    Science.gov (United States)

    Polivka, Jiri; Janku, Filip

    2014-05-01

    Aberrations in various cellular signaling pathways are instrumental in regulating cellular metabolism, tumor development, growth, proliferation, metastasis and cytoskeletal reorganization. The fundamental cellular signaling cascade involved in these processes, the phosphatidylinositol 3-kinase/protein kinase-B/mammalian target of rapamycin (PI3K/AKT/mTOR), closely related to the mitogen-activated protein kinase (MAPK) pathway, is a crucial and intensively explored intracellular signaling pathway in tumorigenesis. Various activating mutations in oncogenes together with the inactivation of tumor suppressor genes are found in diverse malignancies across almost all members of the pathway. Substantial progress in uncovering PI3K/AKT/mTOR alterations and their roles in tumorigenesis has enabled the development of novel targeted molecules with potential for developing efficacious anticancer treatment. Two approved anticancer drugs, everolimus and temsirolimus, exemplify targeted inhibition of PI3K/AKT/mTOR in the clinic and many others are in preclinical development as well as being tested in early clinical trials for many different types of cancer. This review focuses on targeted PI3K/AKT/mTOR signaling from the perspective of novel molecular targets for cancer therapy found in key pathway members and their corresponding experimental therapeutic agents. Various aberrant prognostic and predictive biomarkers are also discussed and examples are given. Novel approaches to PI3K/AKT/mTOR pathway inhibition together with a better understanding of prognostic and predictive markers have the potential to significantly improve the future care of cancer patients in the current era of personalized cancer medicine.

  10. Interfering with Resistance to Smoothened Antagonists by Inhibition of the PI3K Pathway in Medulloblastoma

    Science.gov (United States)

    Buonamici, Silvia; Williams, Juliet; Morrissey, Michael; Wang, Anlai; Guo, Ribo; Vattay, Anthony; Hsiao, Kathy; Yuan, Jing; Green, John; Ospina, Beatrice; Yu, Qunyan; Ostrom, Lance; Fordjour, Paul; Anderson, Dustin L.; Monahan, John E.; Kelleher, Joseph F.; Peukert, Stefan; Pan, Shifeng; Wu, Xu; Maira, Sauveur-Michel; Garcia-Echeverria, Carlos; Briggs, Kimberly J.; Watkins, D. Neil; Yao, Yung-mae; Lengauer, Christoph; Warmuth, Markus; Sellers, William R.; Dorsch, Marion

    2012-01-01

    Mutations in Hedgehog (Hh) pathway genes, leading to constitutive activation of Smoothened (Smo), occur in medulloblastoma. Antagonists of Smo induce tumor regression in mouse models of medulloblastoma and hold great promise for treating this disease. However, acquired resistance has emerged as a challenge to targeted therapeutics and may limit their anti-cancer efficacy. Here, we describe novel mechanisms of acquired resistance to Smo antagonists in medulloblastoma. NVP-LDE225, a potent and selective Smo antagonist, inhibits Hh signaling and induces tumor regressions in allograft models of medulloblastoma that are driven by mutations of Patched (Ptch), a tumor suppressor in the Hh pathway. However, evidence of resistance was observed during the course of treatment. Molecular analysis of resistant tumors revealed distinct resistance mechanisms. Chromosomal amplification of Gli2, a downstream effector of Hh signaling, or more rarely point mutations in Smo led to reactivated Hh signaling and restored tumor growth. Unexpectedly, analysis of pathway gene-expression signatures selectively deregulated in resistant tumors identified increased phosphoinositide 3-kinase (PI3K) signaling as another potential resistance mechanism. Probing the functional relevance of increased PI3K signaling, we demonstrated that the combination of NVP-LDE225 with the PI3K class I inhibitor NVP-BKM120 or the dual PI3K/mTOR inhibitor NVP-BEZ235 markedly delayed the development of resistance. Our findings have important clinical implications for future treatment strategies in medulloblastoma. PMID:20881279

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

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

    2015-03-01

    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.

  12. p38MAPK, ERK and PI3K signaling pathways are involved in C5a-primed neutrophils for ANCA-mediated activation.

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    Jian Hao

    Full Text Available BACKGROUND: The complement system is one of the important contributing factors in the development of antineutrophil cytoplasmic antibody (ANCA-associated vasculitis (AAV. C5a and the neutrophil C5a receptor play a central role in antineutrophil cytoplasmic antibody (ANCA-mediated neutrophil recruitment and activation. The current study further investigated the signaling pathways of C5a-mediated priming of human neutrophils for ANCA-induced neutrophil activation. METHODOLOGY/PRINCIPAL FINDINGS: The effects of the p38 mitogen-activated protein kinase (p38MAPK inhibitor (SB202190, extracellular signal-regulated kinase (ERK inhibitor (PD98059, c-Jun N-terminal kinase (JNK inhibitor (6o and phosphoinositol 3-kinase (PI3K inhibitor (LY294002 were tested on respiratory burst and degranulation of C5a-primed neutrophils activated with ANCA, as well as on C5a-induced increase in expression of membrane-bound PR3 (mPR3 on neutrophils. For C5a-primed neutrophils for MPO-ANCA-induced respiratory burst, the mean fluorescence intensity (MFI value was 254.8±67.1, which decreased to 203.6±60.3, 204.4±36.7, 202.4±49.9 and 188±47.9 upon pre-incubation with SB202190, PD98059, LY294002 and the mixture of above-mentioned three inhibitors (compared with that without inhibitors, P<0.01, P<0.05, P<0.01 and P<0.05, respectively. For PR3-ANCA-positive IgG, the MFI value increased in C5a-primed neutrophils, which decreased upon pre-incubation with above-mentioned inhibitors. The lactoferrin concentration increased in C5a-primed neutrophils induced by MPO or PR3-ANCA-positive IgG supernatant and decreased upon pre-incubation with above-mentioned three inhibitors. mPR3 expression increased from 923.3±182.4 in untreated cells to 1278.3±299.3 after C5a treatment and decreased to 1069.9±188.9, 1100±238.2, 1092.3±231.8 and 1053.9±200.3 by SB202190, PD98059, LY294002 and the mixture of above-mentioned three inhibitors (compared with that without inhibitors, P<0.01, P<0

  13. Inhibition of Autophagy via Activation of PI3K/Akt Pathway Contributes to the Protection of Ginsenoside Rb1 against Neuronal Death Caused by Ischemic Insults

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    Tianfei Luo

    2014-09-01

    Full Text Available Lethal autophagy is a pathway leading to neuronal death caused by transient global ischemia. In this study, we examined the effect of Ginsenoside Rb1 (GRb1 on ischemia/reperfusion-induced autophagic neuronal death and investigated the role of PI3K/Akt. Ischemic neuronal death in vitro was induced by using oxygen glucose deprivation (OGD in SH-SY5Y cells, and transient global ischemia was produced by using two vessels occlusion in rats. Cellular viability of SH-SY5Y cells was assessed by MTT assay, and CA1 neuronal death was evaluated by Hematoxylin-eosin staining. Autophagic vacuoles were detected by using both fluorescent microscopy in combination with acridine orange (AO and Monodansylcadaverine (MDC staining and transmission electronic microscopy. Protein levels of LC3II, Beclin1, total Akt and phosphor-Akt at Ser473 were examined by western blotting analysis. GRb1 inhibited both OGD and transient ischemia-induced neuronal death and mitigated OGD-induced autophagic vacuoles in SH-SY5Y cells. By contrast, PI3K inhibitor LY294002 counteracted the protection of GRb1 against neuronal death caused by either OGD or transient ischemia. LY294002 not only mitigated the up-regulated protein level of phosphor Akt at Ser473 caused by GRb1, but also reversed the inhibitory effect of GRb1 on OGD and transient ischemia-induced elevation in protein levels of LC3II and Beclin1.

  14. Transient Acidosis during Early Reperfusion Attenuates Myocardium Ischemia Reperfusion Injury via PI3k-Akt-eNOS Signaling Pathway

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    Xin Qiao

    2013-01-01

    Full Text Available In this paper, we concluded that transient acidosis reperfusion conferred cardioprotection against myocardial ischemia reperfusion injury in isolated rat hearts through activating PI3K-Akt-eNOS pathway.

  15. Differential effects of selective inhibitors targeting the PI3K/AKT/mTOR pathway in acute lymphoblastic leukemia.

    Science.gov (United States)

    Badura, Susanne; Tesanovic, Tamara; Pfeifer, Heike; Wystub, Sylvia; Nijmeijer, Bart A; Liebermann, Marcus; Falkenburg, J H Frederik; Ruthardt, Martin; Ottmann, Oliver G

    2013-01-01

    Aberrant PI3K/AKT/mTOR signaling has been linked to oncogenesis and therapy resistance in various malignancies including leukemias. In Philadelphia chromosome (Ph) positive leukemias, activation of PI3K by dysregulated BCR-ABL tyrosine kinase (TK) contributes to the pathogenesis and development of resistance to ABL-TK inhibitors (TKI). The PI3K pathway thus is an attractive therapeutic target in BCR-ABL positive leukemias, but its role in BCR-ABL negative ALL is conjectural. Moreover, the functional contribution of individual components of the PI3K pathway in ALL has not been established. We compared the activity of the ATP-competitive pan-PI3K inhibitor NVP-BKM120, the allosteric mTORC1 inhibitor RAD001, the ATP-competitive dual PI3K/mTORC1/C2 inhibitors NVP-BEZ235 and NVP-BGT226 and the combined mTORC1 and mTORC2 inhibitors Torin 1, PP242 and KU-0063794 using long-term cultures of ALL cells (ALL-LTC) from patients with B-precursor ALL that expressed the BCR-ABL or TEL-ABL oncoproteins or were BCR-ABL negative. Dual PI3K/mTOR inhibitors profoundly inhibited growth and survival of ALL cells irrespective of their genetic subtype and their responsiveness to ABL-TKI. Combined suppression of PI3K, mTORC1 and mTORC2 displayed greater antileukemic activity than selective inhibitors of PI3K, mTORC1 or mTORC1 and mTORC2. Inhibition of the PI3K/mTOR pathway is a promising therapeutic approach in patients with ALL. Greater antileukemic activity of dual PI3K/mTORC1/C2 inhibitors appears to be due to the redundant function of PI3K and mTOR. Clinical trials examining dual PI3K/mTORC1/C2 inhibitors in patients with B-precursor ALL are warranted, and should not be restricted to particular genetic subtypes.

  16. Differential effects of selective inhibitors targeting the PI3K/AKT/mTOR pathway in acute lymphoblastic leukemia.

    Directory of Open Access Journals (Sweden)

    Susanne Badura

    Full Text Available PURPOSE: Aberrant PI3K/AKT/mTOR signaling has been linked to oncogenesis and therapy resistance in various malignancies including leukemias. In Philadelphia chromosome (Ph positive leukemias, activation of PI3K by dysregulated BCR-ABL tyrosine kinase (TK contributes to the pathogenesis and development of resistance to ABL-TK inhibitors (TKI. The PI3K pathway thus is an attractive therapeutic target in BCR-ABL positive leukemias, but its role in BCR-ABL negative ALL is conjectural. Moreover, the functional contribution of individual components of the PI3K pathway in ALL has not been established. EXPERIMENTAL DESIGN: We compared the activity of the ATP-competitive pan-PI3K inhibitor NVP-BKM120, the allosteric mTORC1 inhibitor RAD001, the ATP-competitive dual PI3K/mTORC1/C2 inhibitors NVP-BEZ235 and NVP-BGT226 and the combined mTORC1 and mTORC2 inhibitors Torin 1, PP242 and KU-0063794 using long-term cultures of ALL cells (ALL-LTC from patients with B-precursor ALL that expressed the BCR-ABL or TEL-ABL oncoproteins or were BCR-ABL negative. RESULTS: Dual PI3K/mTOR inhibitors profoundly inhibited growth and survival of ALL cells irrespective of their genetic subtype and their responsiveness to ABL-TKI. Combined suppression of PI3K, mTORC1 and mTORC2 displayed greater antileukemic activity than selective inhibitors of PI3K, mTORC1 or mTORC1 and mTORC2. CONCLUSIONS: Inhibition of the PI3K/mTOR pathway is a promising therapeutic approach in patients with ALL. Greater antileukemic activity of dual PI3K/mTORC1/C2 inhibitors appears to be due to the redundant function of PI3K and mTOR. Clinical trials examining dual PI3K/mTORC1/C2 inhibitors in patients with B-precursor ALL are warranted, and should not be restricted to particular genetic subtypes.

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

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    Suman, Shubhankar [Department of Biochemistry and Molecular and Cellular Biology, Georgetown University, Washington, DC (United States); Johnson, Michael D. [Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC (United States); Fornace, Albert J. [Department of Biochemistry and Molecular and Cellular Biology, Georgetown University, Washington, DC (United States); Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC (United States); Datta, Kamal, E-mail: kd257@georgetown.edu [Department of Biochemistry and Molecular and Cellular Biology, Georgetown University, Washington, DC (United States)

    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.

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

    Science.gov (United States)

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

    2016-04-05

    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.

  19. Lovastatin protects mesenchymal stem cells against hypoxia and serum deprivation-induced apoptosis through activation of PI3K/Akt and ERK1/2 signaling pathways%洛伐他汀经PI3K/Akt和ERK1/2信号通路抑制大鼠骨髓间充质干细胞凋亡

    Institute of Scientific and Technical Information of China (English)

    徐瑞霞; 陈曦; 胡盛寿; 陈静海; 刘学文; 刘学彬; 石林惠; 丛祥凤

    2008-01-01

    Objective To investigated the effect of lovastatin on hypoxia and serum deprivation (Hypoxia/SD) induced rat MSCs apoptosis in vitro and associated signaling pathway changes. Methods MSCs were isolated from Sprague-Dawley rats. The anti-apoptotic effects of lovastatin were detected using Hoechst33342 and annexin V-FITC/PI binding assay by Flow cytometric analysis. The phosphorylation of Akt and ERK1/2, the cytochrome C and the cleaved caspase-3 were detected by Western blot. Results Lovastatin (0. 01 - 1 μmol/L)significantly reduced Hypoxia/SD-induced MSCs apoptosis and increased Akt phosphorylation, reduced caspase-3 activation and cytochrome c release from mitochondria to cytosol in a time dependent manner. These effects could be significantly blocked by both PI3K inhibitor, LY294002 and ERK1/2 inhibitor, U0126. Conclusions Our results showed that lovastatin protects MSCs from Hypoxia/ SD-induced apoptosis via activating PI3K/Akt and ERK1/2 signaling pathways suggesting a potential role of statins as an adjunct therapeutic agent during transplanting MSCs into damaged heart after myocardial infarction.%目的 体外以缺氧无血清条件模拟心肌梗死后的心脏缺血微环境,研究洛伐他汀能否抑制缺氧无血清引起的骨髓间充质干细胞(MSC)凋亡并探讨其机制.方法 以Hocchst33342染色荧光显微镜观察法及Annexin V/PI流式细胞术检测洛伐他汀的抗凋亡作用,并进一步采用Westernblot方法 检测洛伐他汀对线粒体凋亡途径的抑制作用以及对磷脂酰肌醇3激酶(PI3K)/丝氨酸苏氨酸激酶(Akt)途径和丝裂原活化的蛋白激酶(MAPK)的激酶(MEK)/细胞内信号调节蛋白激酶(ERK1/2)途径的激活作用.结果 0.01~1 μmol/L浓度范围的洛伐他汀能够有效地抑制缺氧无血清引起的MSC凋亡.洛伐他汀抑制线粒体凋亡途径,洛伐他汀抑制细胞色素C释放,降低天冬氨酸特异性半胱氨酸蛋白酶-3(caspase-3)活化,从而保护线粒体功能.洛

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

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

    2012-12-01

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

  4. Neuroprotective effect of resveratrol against brain ischemia reperfusion injury in rats entails reduction of DJ-1 protein expression and activation of PI3K/Akt/GSK3b survival pathway.

    Science.gov (United States)

    Abdel-Aleem, Ghada A; Khaleel, Eman F; Mostafa, Dalia G; Elberier, Lydia K

    2016-10-01

    In the current study, we aimed to investigate the mechanistic role of DJ-1/PI3K/Akt survival pathway in ischemia/reperfusion (I/R) induced cerebral damage and to investigate if the resveratrol (RES) mediates its ischemic neuroptotection through this pathway. RES administration to Sham rats boosted glutathione level and superoxide dismutase activity and downregulated inducible nitric oxide synthase expression without affecting redox levels of DJ-1 forms or components of PI3K/Akt pathway including PTEN, p-Akt or p/p-GSK3b. However, RES pre-administration to I/R rats reduced infarction area, oxidative stress, inflammation and apoptosis. Concomitantly, RES ameliorated the decreased levels of oxidized forms of DJ-1 and enhancing its reduction, increased the nuclear protein expression of Nfr-2 and led to activation of PI3K/Akt survival pathway. In conclusion, overoxidation of DJ-1 is a major factor that contributes to post-I/R cerebral damage and its reduction by RES could explain the neuroprotection offered by RES.

  5. ICAM-3, radiation resistance gene, activates PI3K/Akt-CREB-MMPs pathway and promotes migration/invasion of the human non-small cell lung cancer cell NCI-H1299

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    Park, Jong Kuk; Park, Seon Ho; Hong, Sung Hee; Um, Hong Duck [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Yoo, Young Do [Korea Univ., Seoul (Korea, Republic of)

    2008-05-15

    Cancer cell is characterized by various distinctive functions difference from normal cell. The one of specific properties of cancer is invasion and metastasis. Invasion and metastasis is a multi-step process involving over-expression of proteolytic enzymes such as matrix metalloproteinases (MMPs) and critically dependent on the ability of cells to move away from the primary tumor to gain access to the vascular or lymphatic systems which disperses cells to distant sites, where they can grow in a permissive microenvironment at a secondary location. All of these processes are critically dependent upon the ability of cancer cells to breach the basement membrane and to migrate through neighboring tissues. Cancer cell invasion is an important, tightly regulated process that is related with development, immune response and wound healing. This invasive response is dependent on activation of signaling pathways that result in both short-term and long-term cellular responses. The gene expressions of the cancer cell invasion related-proteolytic enzymes are regulated at the transcriptional level (through AP-1 and NF-kB via mitogen activated protein kinases (MAPKs) and PI3K-Akt pathways) and post-transcriptional levels, and the protein level via their activators or inhibitors, and their cell surface localization. Therefore, the related proteins such as MMPs, MAPK, PI3K, Akt and their regulatory pathway have been considered as promising targets for anti-cancer drugs. In previous reports, Intercellular adherin molecule-3 (ICAM-3) showed increase of radio-resistance and proliferation. We have made ICAM-3 overexpressed cancer cells which shows elevated level of invasion compared with normal cancer cells and its invasion capacity was down regulated with treatment of specific inhibitor for PI3K. These results suggest that ICAM-3 related invasion is associated with PI3K signaling pathway.

  6. Salidroside attenuates myocardial ischemia-reperfusion injury via PI3K/Akt signaling pathway.

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    Xu, Mao-Chun; Shi, Hai-Ming; Gao, Xiu-Fang; Wang, Hao

    2013-01-01

    To investigate the cardioprotective effects of salidroside on myocardial ischemia-reperfusion injury (IRI) in rabbits and the underlying action mechanisms in PI3K/Akt signaling pathway, a rabbit ischemia/reperfusion model was created by ligating the left anterior descending coronary arterial branch for 30 min and by releasing the ligature to allow reperfusion for 120 min. Salidroside or salidroside+PI3K inhibitor (LY294002) was administered via intracoronary injections at the onset of reperfusion. Apoptosis of cardiomyocytes was assessed by terminal dUTP nick-end labeling assay, and the expression of apoptosis-related proteins was observed by immunohistochemistry. The expressions of total Akt and phosphorylated Akt (p-Akt) were detected by western blot analysis. The results showed that intracoronary injection of salidroside at the onset of reperfusion markedly reduced the apoptosis of cardiomyocytes, significantly increasing Bcl-2 and p-Akt proteins expressions and decreasing Bax and caspase-3 expressions in the hearts subjected to ischemia followed by 120-min reperfusion. However, the anti-apoptotic effect induced by salidroside was inhibited by LY294002, which blocked the activation of Akt. These results suggested that intracoronary administration of salidroside at the onset of reperfusion could significantly reduce the IRI-induced apoptosis of cardiomyocytes, and this protective mechanism seemed to be mediated by the PI3K-Akt signaling pathway.

  7. Downregulation of wild-type p53 protein by HER-2/neu mediated PI3K pathway activation in human breast cancer cells:its effect on cell proliferation and implication for therapy

    Institute of Scientific and Technical Information of China (English)

    Li ZHENG; Jia Qiang REN; Hua LI; Zhao Lu KONG; Hong Guang ZHU

    2004-01-01

    Overexpression and activation of HER-2/neu (also known as c-erbB-2), a proto-oncogene, was found in about 30%of human breast cancers, promoting cancer growth and making cancer cells resistant to chemo- and radio-therapy.Wild-type p53 is crucial in regulating cell growth and apoptosis and is found to be mutated or deleted in 60-70% of human cancers. And some cancers with a wild-type p53 do not have normal p53 function, suggesting that it is implicated in a complex process regulated by many factors. In the present study, we showed that the overexpression of HER-2/neu could decrease the amount of wild-type p53 protein via activating PI3K pathway, as well as inducing MDM2 nuclear translocation in MCF7 human breast cancer ceils. Blockage of PI3K pathway with its specific inhibitor LY294002 caused G1-S phase arrest, decreased cell growth rate and increased chemo- and radio-therapeutic sensitivity in MCF7 cells expressing wild-type p53. However, it did not increase the sensitivity to adriamycin in MDA-MB-453 breast cancer cells containing mutant p53. Our study indicates that blocking PI3K pathway activation mediated by HER-2/neu overexpression may be useful in the treatment of breast tumors with HER-2/neu overexpression and wild-type p53.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

  10. The rLrp of Mycobacterium tuberculosis inhibits proinflammatory cytokine production and downregulates APC function in mouse macrophages via a TLR2-mediated PI3K/Akt pathway activation-dependent mechanism.

    Science.gov (United States)

    Liu, Yuan; Li, Jia-Yun; Chen, Su-Ting; Huang, Hai-Rong; Cai, Hong

    2016-11-01

    We demonstrate that Mycobacterium tuberculosis recombinant leucine-responsive regulatory protein (rLrp) inhibits lipopolysaccharide (LPS)-induced tumor necrosis factor alpha (TNF-α), interleukin-6, and interleukin-12 production and blocks the nuclear translocation of subunits of the nuclear-receptor transcription factor NF-κB (Nuclear factor-kappa B). Moreover, rLrp attenuated LPS-induced DNA binding and NF-κB transcriptional activity, which was accompanied by the degradation of inhibitory IκBα and a consequent decrease in the nuclear translocation of the NF-κB p65 subunit. RLrp interfered with the LPS-induced clustering of TNF receptor-associated factor 6 and with interleukin-1 receptor-associated kinase 1 binding to TAK1. Furthermore, rLrp did not attenuate proinflammatory cytokines or the expression of CD86 and major histocompatibility complex class-II induced by interferon-gamma in the macrophages of Toll-like receptor 2 deletion (TLR2(-/-)) mice and in protein kinase b (Akt)-depleted mouse cells, indicating that the inhibitory effects of rLrp were dependent on TLR2-mediated activation of the phosphatidylinositol 3-OH kinase (PI3K)/Akt pathway. RLrp could also activate the PI3K/Akt pathway by stimulating the rapid phosphorylation of PI3K, Akt, and glycogen synthase kinase 3 beta in macrophages. In addition, 19 amino acid residues in the N-terminus of rLrp were determined to be important and required for the inhibitory effects mediated by TLR2. The inhibitory function of these 19 amino acids of rLrp raises the possibility that mimetic inhibitory peptides could be used to restrict innate immune responses in situations in which prolonged TLR signaling has deleterious effects. Our study offers new insight into the inhibitory mechanisms by which the TLR2-mediated PI3K/Akt pathway ensures the transient expression of potent inflammatory mediators.

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

    Directory of Open Access Journals (Sweden)

    Wang Y

    2016-01-01

    Full Text Available Yong Wang,1 Yu Gan,1 Zhengyu Tan,1 Jun Zhou,1 Riko Kitazawa,2 Xianzhen Jiang,1 Yuxin Tang,1 Jianfu Yang11Department of Urology, The Third Xiangya Hospital of Central South University, Changsha, People’s Republic of China; 2Department of Diagnostic Pathology, Ehime University Hospital, Shitsukawa, Tōon, Ehime Perfecture, JapanAbstract: 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

  12. Adiponectin Induces Oncostatin M Expression in Osteoblasts through the PI3K/Akt Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Chen-Ming Su

    2015-12-01

    Full Text Available Rheumatoid arthritis (RA, a common autoimmune disorder, is associated with a chronic inflammatory response and unbalanced bone metabolism within the articular microenvironment. Adiponectin, an adipokine secreted by adipocytes, is involved in multiple functions, including lipid metabolism and pro-inflammatory activity. However, the mechanism of adiponectin performance within arthritic inflammation remains unclear. In this study, we observed the effect of adiponectin on the expression of oncostatin M (OSM, a pro-inflammatory cytokine, in human osteoblastic cells. Pretreatment of cells with inhibitors of phosphatidylinositol 3-kinase (PI3K, Akt, and nuclear factor (NF-κB reduced the adiponectin-induced OSM expression in osteoblasts. Stimulation of the cells with adiponectin increased phosphorylation of PI3K, Akt, and p65. Adiponectin treatment of osteoblasts increased OSM-luciferase activity and p65 binding to NF-κB on the OSM promoter. Our results indicate that adiponectin increased OSM expression via the PI3K, Akt, and NF-κB signaling pathways in osteoblastic cells, suggesting that adiponectin is a novel target for arthritis treatment.

  13. Activation of PI3K signaling prevents aminoglycoside-induced hair cell death in the murine cochlea

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    Azadeh Jadali

    2016-06-01

    Full Text Available 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.

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

    Science.gov (United States)

    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.

  15. 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

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Tao Fang; Wang, Heng [Department of Orthopedics, First Affiliated Hospital of Nanchang University, Jiangxi (China); Peng, Ai Fen [Jiangxi University of Traditional Chinese Medicine, Jiangxi (China); Luo, Qing Feng [Department of Pathology, Cancer Hospital of Jiangxi Province, Jiangxi (China); Liu, Zhi Li, E-mail: zgm7977@163.com [Department of Orthopedics, First Affiliated Hospital of Nanchang University, Jiangxi (China); Zhou, Rong Ping [Department of Orthopedics, Second Affiliated Hospital of Nanchang University, Jiangxi (China); Gao, Song; Zhou, Yang; Chen, Wen Zhao [Department of Orthopedics, First Affiliated Hospital of Nanchang University, Jiangxi (China)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Liping [Division of Nephrology, Shenzhen People' s Hospital, Second Clinical Medical College, Jinan University, Shenzhen 518020 (China); Wang, Shixuan [Renal Division, Brigham and Women' s Hospital and Harvard Medical School, Boston, MA 02115 (United States); Hu, Chaofeng [Department of Pathophysiology, Medical College, Jinan University, Guangzhou, 510632 (China); Zhang, Xinzhou, E-mail: slp08@126.com [Division of Nephrology, Shenzhen People' s Hospital, Second Clinical Medical College, Jinan University, Shenzhen 518020 (China)

    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.

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

    Science.gov (United States)

    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

  18. Advancement of PI3K-mTOR signaling pathway%PI3K-mTOR信号通路的研究进展

    Institute of Scientific and Technical Information of China (English)

    周虹; 文富强; 黄向阳

    2008-01-01

    Previous studies have demonstrated that phosphoinositide-3-kinase/tbe mammalian target of rapamycin(PI3K-mTOR) signaling pathway can be involved in a number of cellular processes including cell proliferation, differentiation, survival, and tumor growth. This review describs the recent advances in understanding the PI3K-mTOR signaling pathway, the PI3K-mTOR inhibitors, and also the regulation and the role of PI3K-mTOR pathway. Also it sheds light on investigations between interferon-alpha and PI3KmTOR pathway.%PI3K-mTOR(phosphoinositide-3一kinase/the mammalian target of rapamycin)信号通路在细胞的生长、分化、凋亡等方面都发挥着重要作用,文章对该通路的组成、调节、效应、抑制剂及其应用等方面作了介绍,并阐述了干扰素α通过该信号通路刺激基因表达的研究现况.

  19. Target regulation of PI3K/Akt/mTOR pathway by cannabidiol in treatment of experimental multiple sclerosis.

    Science.gov (United States)

    Giacoppo, Sabrina; Pollastro, Federica; Grassi, Gianpaolo; Bramanti, Placido; Mazzon, Emanuela

    2017-01-01

    This study was aimed to investigate whether treatment with purified cannabidiol (CBD) may counteract the development of experimental multiple sclerosis (MS), by targeting the PI3K/Akt/mTOR pathway. Although the PI3K/Akt/mTOR pathway was found to be activated by cannabinoids in several immune and non-immune cells, currently, there is no data about the effects of CBD in the PI3K/Akt/mTOR activity in MS. Experimental Autoimmune Encephalomyelitis (EAE), the most common model of MS, was induced in C57BL/6 mice by immunization with myelin oligodendroglial glycoprotein peptide (MOG)35-55. After EAE onset, which occurs approximately 14days after disease induction, mice were daily intraperitoneally treated with CBD (10mg/kg mouse) and observed for clinical signs of EAE. At 28days from EAE-induction, mice were euthanized and spinal cord tissues were sampled to perform immunohistochemical evaluations and western blot analysis. Our results showed a clear downregulation of the PI3K/Akt/mTOR pathway following EAE induction. CBD treatment was able to restore it, increasing significantly the phosphorylation of PI3K, Akt and mTOR. Also, an increased level of BNDF in CBD-treated mice seems to be involved in the activation of PI3K/Akt/mTOR pathway. In addition, our data demonstrated that therapeutic efficacy of CBD treatment is due to reduction of pro-inflammatory cytokines, like IFN-γ and IL-17 together with an up-regulation of PPARγ. Finally, CBD was found to promote neuronal survival by inhibiting JNK and p38 MAP kinases. These results provide an interesting discovery about the regulation of the PI3K/Akt/mTOR pathway by cannabidiol administration, that could be a new potential therapeutic target for MS management.

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

    Science.gov (United States)

    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

  1. Feedback upregulation of HER3 (ErbB3) expression and activity attenuates antitumor effect of PI3K inhibitors

    Science.gov (United States)

    Chakrabarty, Anindita; Sánchez, Violeta; Kuba, María G.; Rinehart, Cammie; Arteaga, Carlos L.

    2012-01-01

    We examined the effects of an inhibitor of PI3K, XL147, against human breast cancer cell lines with constitutive PI3K activation. Treatment with XL147 resulted in dose-dependent inhibition of cell growth and levels of pAKT and pS6, signal transducers in the PI3K/AKT/TOR pathway. In HER2-overexpressing cells, inhibition of PI3K was followed by up-regulation of expression and phosphorylation of multiple receptor tyrosine kinases, including HER3. Knockdown of FoxO1 and FoxO3a transcription factors suppressed the induction of HER3, InsR, IGF1R, and FGFR2 mRNAs upon inhibition of PI3K. In HER2+ cells, knockdown of HER3 with siRNA or cotreatment with the HER2 inhibitors trastuzumab or lapatinib enhanced XL147-induced cell death and inhibition of pAKT and pS6. Trastuzumab and lapatinib each synergized with XL147 for inhibition of pAKT and growth of established BT474 xenografts. These data suggest that PI3K antagonists will inhibit AKT and relieve suppression of receptor tyrosine kinase expression and their activity. Relief of this feedback limits the sustained inhibition of the PI3K/AKT pathway and attenuates the response to these agents. As a result, PI3K pathway inhibitors may have limited clinical activity overall if used as single agents. In patients with HER2-overexpressing breast cancer, PI3K inhibitors should be used in combination with HER2/HER3 antagonists. PMID:21368164

  2. SMAD-PI3K-Akt-mTOR pathway mediates BMP-7 polarization of monocytes into M2 macrophages.

    Directory of Open Access Journals (Sweden)

    Crystal Rocher

    Full Text Available Previously we demonstrated that bone morphogenetic protein-7 (BMP-7 treatment polarizes monocytes into M2 macrophages and increases the expression of anti-inflammatory cytokines. Despite these findings, the mechanisms for the observed BMP-7 induced monocyte polarization into M2 macrophages are completely unknown. In this study, we demonstrate the mechanisms involved in the polarization of monocytes into M2 macrophages. Apoptotic conditioned media (ACM was generated to mimic the stressed conditions, inducing monocyte polarization. Monocytes were treated with ACM along with BMP-7 and/or its inhibitor, follistatin, for 48 hours. Furthermore, an inhibitor of the PI3K pathway, LY-294002, was also studied. Our data show that BMP-7 induces polarization of monocytes into M2 macrophages while significantly increasing the expression of anti-inflammatory markers, arginase-1 and IL-10, and significantly (p<0.05 decreasing the expression of pro-inflammatory markers iNOS, IL-6, TNF-α and MCP-1; (p<0.05. Moreover, addition of the PI3K inhibitor, LY-294002, significantly (p<0.05 decreases upregulation of IL-10 and arginase-1, suggesting involvement of the PI3K pathway in M2 macrophage polarization. Next, following BMP-7 treatment, a significant (p<0.05 increase in p-SMAD1/5/8 and p-PI3K expression resulting in downstream activation of p-Akt and p-mTOR was observed. Furthermore, expression of p-PTEN, an inhibitor of the PI3K pathway, was significantly (p<0.05 increased in the ACM group. However, BMP-7 treatment inhibited its expression, suggesting involvement of the PI3K-Akt-mTOR pathway. In conclusion, we demonstrate that BMP-7 polarizes monocytes into M2 macrophages and enhances anti-inflammatory cytokine expression which is mediated by the activated SMAD-PI3K-Akt-mTOR pathway.

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Monterrubio, Maria; Mellado, Mario; Carrera, Ana C. [Department of Immunology and Oncology, Centro Nacional de Biotecnologia/CSIC, Campus de Cantoblanco, E-28049 Madrid (Spain); Rodriguez-Frade, Jose Miguel, E-mail: jmrfrade@cnb.csic.es [Department of Immunology and Oncology, Centro Nacional de Biotecnologia/CSIC, Campus de Cantoblanco, E-28049 Madrid (Spain)

    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.

  5. Targeting the PI3K/mTOR Pathway in Pediatric Hematologic Malignancies

    Directory of Open Access Journals (Sweden)

    Sarah K Tasian

    2014-05-01

    Full Text Available A complex interplay of intracellular signaling networks orchestrates normal cell growth and survival, including translation, transcription, proliferation, and cell cycle progression. Dysregulation of such signals occurs commonly in many malignancies, thereby giving the cancer cell a survival advantage, but also providing possible targets for therapeutic intervention. Activation of the phosphatidylinositol 3-kinase (PI3K/protein kinase B (Akt/mammalian target of rapamycin (mTOR signaling pathway contributes to the proliferative advantage of malignant cells and may confer resistance to chemotherapy in various hematologic malignancies. The initial mTOR inhibitor, sirolimus (also known as rapamycin, was first discovered in 1975 in the soil of Easter Island. Sirolimus was originally developed as an anti-fungal agent given its macrolide properties, but was approved by the Food and Drug Administration (FDA in 1999 as an immunosuppressive agent for renal transplantation patients once its T cell suppression characteristics were recognized. Shortly thereafter, recognition of sirolimus’s ability to inhibit cellular proliferation and cell cycle progression brought sirolimus to the forefront as a possible inhibitor of mTOR. In the subsequent decade, the functional roles of the mTOR protein have been more fully elucidated, and this protein is now known to be a key regulator in a highly complex signaling pathway that controls cell growth, proliferation, metabolism, and apoptosis. This article discusses the dysregulation of PI3K/mTOR signaling in hematologic malignancies, including acute and chronic leukemias, lymphomas, and lymphoproliferative disorders. The current repertoire of PI3K/mTOR pathway inhibitors in development and clinical trials to date are described with emphasis upon pediatric hematologic malignancies (Figure 1. Investigation of small molecule inhibitors of this complex signaling network is an active area of oncology drug development.

  6. The PI3K/Akt/mTOR pathway in ovarian cancer:therapeutic opportunities and challenges

    Institute of Scientific and Technical Information of China (English)

    Bianca Cheaib; Aurlie Auguste; Alexandra Leary

    2015-01-01

    The phosphatidylinositol 3 kinase (PI3K) pathway is frequently altered in cancer, including ovarian cancer (OC). Unfortunately, despite a sound biological rationale and encouraging activity in preclinical models, trials of first-generation inhibitors of mammalian target of rapamycin (mTOR) in OC have demonstrated negative results. The lack of patient selection as well as resistance to selective mTOR complex-1 (mTORC1) inhibitors could explain the disappointing results thus far. Nonetheless, a number of novel agents are being investigated, including dual mTORC1/mTORC2, Akt, and PI3K inhibitors. Although it is likely that inhibition of the PI3K/Akt/mTOR pathway may have little effect in unselected OC patients, certain histological types, such as clear cell or endometrioid OC with frequent phosphatidylinositol-4,5-biphosphate 3-kinase, catalytic subunit alpha (PIK3CA) and/or phosphatase and tensin homolog (PTEN) alterations, may be particularly suited to this approach. Given the complexity and redundancy of the PI3K signaling network, PI3K pathway inhibition may be most useful in combination with either chemotherapy or other targeted therapies, such as MEK inhibitors, anti-angiogenic therapy, and hormonal therapy, in appropriately selected OC patients. Here, we discuss the relevance of the PI3K pathway in OC and provide an up-to-date review of clinical trials of novel PI3K inhibitors alone or in combination with cytotoxics and novel therapies in OC. In addition, the challenges of drug resistance and predictive biomarkers are addressed.

  7. Activation of PI3K/AKT and ERK MAPK signal pathways is required for the induction of lytic cycle replication of Kaposi's Sarcoma-associated herpesvirus by herpes simplex virus type 1

    Directory of Open Access Journals (Sweden)

    Lv Zhigang

    2011-10-01

    Full Text Available Abstract Background Kaposi's sarcoma-associated herpesvirus (KSHV is causally linked to several acquired immunodeficiency syndrome-related malignancies, including Kaposi's sarcoma (KS, primary effusion lymphoma (PEL and a subset of multicentric Castleman's disease. Regulation of viral lytic replication is critical to the initiation and progression of KS. Recently, we reported that herpes simplex virus type 1 (HSV-1 was an important cofactor that activated lytic cycle replication of KSHV. Here, we further investigated the possible signal pathways involved in HSV-1-induced reactivation of KSHV. Results By transfecting a series of dominant negative mutants and protein expressing constructs and using pharmacologic inhibitors, we found that either Janus kinase 1 (JAK1/signal transducer and activator of transcription 3 (STAT3 or JAK1/STAT6 signaling failed to regulate HSV-1-induced KSHV replication. However, HSV-1 infection of BCBL-1 cells activated phosphatidylinositol 3-kinase (PI3K/protein kinase B (PKB, also called AKT pathway and inactivated phosphatase and tensin homologue deleted on chromosome ten (PTEN and glycogen synthase kinase-3β (GSK-3β. PTEN/PI3K/AKT/GSK-3β pathway was found to be involved in HSV-1-induced KSHV reactivation. Additionally, extracellular signal-regulated protein kinase (ERK mitogen-activated protein kinase (MAPK pathway also partially contributed to HSV-1-induced KSHV replication. Conclusions HSV-1 infection stimulated PI3K/AKT and ERK MAPK signaling pathways that in turn contributed to KSHV reactivation, which provided further insights into the molecular mechanism controlling KSHV lytic replication, particularly in the context of HSV-1 and KSHV co-infection.

  8. 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

    Science.gov (United States)

    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

  9. Dual PI3K/mTOR inhibition shows antileukemic activity in MLL-rearranged acute myeloid leukemia.

    Science.gov (United States)

    Sandhöfer, N; Metzeler, K H; Rothenberg, M; Herold, T; Tiedt, S; Groiß, V; Carlet, M; Walter, G; Hinrichsen, T; Wachter, O; Grunert, M; Schneider, S; Subklewe, M; Dufour, A; Fröhling, S; Klein, H-G; Hiddemann, W; Jeremias, I; Spiekermann, K

    2015-04-01

    In acute myeloid leukemia (AML), several signaling pathways such as the phosphatidylinositol-3-kinase/AKT and the mammalian target of rapamycin (PI3K/AKT/mTOR) pathway are deregulated and constitutively activated as a consequence of genetic and cytogenetic abnormalities. We tested the effectiveness of PI3K/AKT/mTOR-targeting therapies and tried to identify alterations that associate with treatment sensitivity. By analyzing primary samples and cell lines, we observed a wide range of cytotoxic activity for inhibition of AKT (MK-2206), mTORC1 (rapamycin) and PI3K/mTORC1/2 (BEZ-235) with a high sensitivity of cells carrying an MLL rearrangement. In vivo PI3K/mTOR inhibition delayed tumor progression, reduced tumor load and prolonged survival in an MLL-AF9(+)/FLT3-ITD(+) xenograft mouse model. By performing targeted amplicon sequencing in 38 MLL-AF9(+) and 125 cytogenetically normal AML patient samples, we found a high additional mutation rate for genes involved in growth factor signaling in 79% of all MLL-AF9(+) samples, which could lead to a possible benefit of this cohort. PI3K/mTOR inhibition for 24 h led to the cross-activation of the ERK pathway. Further in vitro studies combining PI3K/mTOR and ERK pathway inhibition revealed highly synergistic effects in apoptosis assays. Our data implicate a possible therapeutic benefit of PI3K/mTOR inhibition in the MLL-mutated subgroup. Inhibiting rescue pathways could improve the therapeutic efficacy of PI3K-targeted therapies in AML.

  10. Ursolic acid increases glucose uptake through the PI3K signaling pathway in adipocytes.

    Directory of Open Access Journals (Sweden)

    Yonghan He

    Full Text Available 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. Furthermore, 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.

  11. Swimming Training Inhibits Type 2 Diabetes-Induced Myocardial Apoptosis Activating the PI3K-Akt Signaling Pathway%游泳训练通过激活PI3K-Akt信号通路抑制2型糖尿病引起的心肌细胞凋亡

    Institute of Scientific and Technical Information of China (English)

    江红轲

    2012-01-01

    ) phosphorylation levels was noteworthy higher than that of other two groups(P <0. 05). Meanwhile, the results also showed that insulin receptor subtype 1 (IR1) expression was down-regulated(P <0.05)and PI3K-Akt signal cascades were inactivated. Correspondingly, swimming exercise could decline the ratio of Bax/Bcl-2, considerably improve the survival pathway and further activate GSK-3β protein phosphorylation { P < 0. 05 ). In addition, swimming exercise also could augment insulin receptor IR1 (P < 0.05) contents. Although the level of IR2 was enhanced, there is no divergence for statistics. Conclusion; Swim training can effectively inhibit type 2 diabetes-induced myocardial apoptosis in Wistar rats. This anti-apoptotic effect may be through, at least in part, increasing the contents of IR1 receptor, and thereby activate PI3K-Akt signal cascade and further decline the phosphorylation expression of its key downstream of protein-GSK-3β, suggesting that swimming training may be an appropriate modality for combating with myocardial cell damage caused by T2DM.

  12. Omentin-1 Stimulates Human Osteoblast Proliferation through PI3K/Akt Signal Pathway

    Directory of Open Access Journals (Sweden)

    Shan-Shan Wu

    2013-01-01

    Full Text Available It has been presumed that adipokines deriving from adipose tissue may play important roles in bone metabolism. Omentin-1, a novel adipokine, which is selectively expressed in visceral adipose tissue, has been reported to stimulate proliferation and inhibit differentiation of mouse osteoblast. However, little information refers to the effect of omentin-1 on human osteoblast (hOB proliferation. The current study examined the potential effects of omentin-1 on proliferation in hOB and the signal pathway involved. Omentin-1 promoted hOB proliferation in a dose-dependent manner as determined by [3H]thymidine incorporation. Western blot analysis revealed that omentin-1 induced activation of Akt (phosphatidylinositol-3 kinase downstream effector and such effect was impeded by transfection of hOB with Akt-siRNA. Furthermore, LY294002 (a selective PI3K inhibitor and HIMO (a selective Akt inhibitor abolished the omentin-1-induced hOB proliferation. These findings indicate that omentin-1 induces hOB proliferation via the PI3K/Akt signaling pathway and suggest that osteoblast is a direct target of omentin-1.

  13. The PI3K inhibitor GS-1101 synergistically potentiates HDAC inhibitor-induced proliferation inhibition and apoptosis through the inactivation of PI3K and ERK pathways

    Science.gov (United States)

    Bodo, Juraj; Zhao, Xiaoxian; Sharma, Arishya; Hill, Brian T.; Portell, Craig A.; Lannutti, Brian J.; Almasan, Alexandru; Hsi, Eric D.

    2013-01-01

    Previously, we showed that inhibition of the protein kinase C β (PKCβ)/AKT pathway augments engagement of the histone deacetylase inhibitor (HDI)-induced apoptosis in lymphoma cells. In the present study, we investigated the cytotoxicity and mechanisms of cell death induced by the delta isoform-specific phosphatidylinositide 3-kinase (PI3K) inhibitor, GS-1101, in combination with the HDI, panobinostat (LBH589) and suberoylanilide hydroxamic acid (SAHA). Lymphoma cell lines and primary Non-Hodgkin Lymphoma (NHL) and chronic lymphocytic leukaemia (CLL) cells were simultaneously treated with the HDI, LBH589 and GS-1101. An interaction of the LBH589/GS-1101 combination was formally examined by using various concentrations of LBH589 and GS-1101. Combined treatment resulted in a synergistic inhibition of proliferation and showed synergistic effect on apoptotic induction in all tested cell lines and primary NHL and CLL cells. This study indicates that interference with PI3K signalling dramatically increases HDI-mediated apoptosis in malignant haematopoietic cells, possibly through both AKT-dependent or AKT- independent mechanisms. Moreover, the increase in HDI-related apoptosis observed in PI3K inhibitor-treated cells appears to be related to the disruption of the extracellular signal-regulated kinase (ERK) signalling pathway. This study provides a strong rational for testing the combination of PI3K inhibitors and HDI in the clinic. PMID:23889282

  14. 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.

    Science.gov (United States)

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

    2013-12-01

    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.

  15. 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

    Energy Technology Data Exchange (ETDEWEB)

    Kook, Sung-Ho [Cluster for Craniofacial Development and Regeneration Research, Institute of Oral Biosciences and School of Dentistry, Chonbuk National University, Jeonju (Korea, Republic of); Lim, Shin-Saeng [School of Dentistry and Dental Research Institute, Seoul National University, Seoul (Korea, Republic of); Cho, Eui-Sic; Lee, Young-Hoon; Han, Seong-Kyu; Lee, Kyung-Yeol [Cluster for Craniofacial Development and Regeneration Research, Institute of Oral Biosciences and School of Dentistry, Chonbuk National University, Jeonju (Korea, Republic of); Kwon, Jungkee [College of Veterinary Medicine, Chonbuk National University, Jeonju (Korea, Republic of); Hwang, Jae-Won; Bae, Cheol-Hyeon [Cluster for Craniofacial Development and Regeneration Research, Institute of Oral Biosciences and School of Dentistry, Chonbuk National University, Jeonju (Korea, Republic of); Seo, Young-Kwon [Research Institute of Biotechnology, Dongguk University, Seoul (Korea, Republic of); Lee, Jeong-Chae, E-mail: leejc88@jbnu.ac.kr [Cluster for Craniofacial Development and Regeneration Research, Institute of Oral Biosciences and School of Dentistry, Chonbuk National University, Jeonju (Korea, Republic of)

    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.

  16. The crossregulation between ERK and PI3K signaling pathways determines the tumoricidal efficacy of MEK inhibitor

    Institute of Scientific and Technical Information of China (English)

    Jae-Kyung Won; Hee Won Yang; Sung-Young Shin; Jong Hoon Lee; Won Do Heo; Kwang-Hyun Cho

    2012-01-01

    MEK inhibitor has been highlighted as a promising anti-tumor drug but its effect has been reported as varying over a wide range depending on patho-physiological conditions.In this study,we employed a systems approach by combining biochemical experimentation with in silico simulations to investigate the resistance mechanism and functional consequences of MEK inhibitor.To this end,we have developed an extended integrative model of ERK and PI3K signaling pathways by considering the crosstalk between Ras and PI3K,and analyzed the resistance mechanism to the MEK inhibitor under various mutational conditions.We found that the phospho-Akt level under the Raf mutation was remarkably augmented by MEK inhibitor,while the phospho-ERK level was almost completely repressed.These results suggest that bypassing of the ERK signal to the PI3K signal causes the resistance to the MEK inhibitor in a complex oncogenic signaling network.We further investigated the underlying mechanism of the drug resistance and revealed that the MEK inhibitor disrupts the negative feedback loops from ERK to SOS and GAB1,but activates the positive feedback loop composed of GAB1,Ras,and PI3K,which induces the bypass of the ERK signal to the PI3K signal.Based on these core feedback circuits,we suggested promising candidates for combination therapy and examined the improved inhibitory effects.

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

    Science.gov (United States)

    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

  18. Reduced signaling of PI3K-Akt and RAS-MAPK pathways is the key target for weight-loss-induced cancer prevention by dietary calorie restriction and/or physical activity.

    Science.gov (United States)

    Standard, Joseph; Jiang, Yu; Yu, Miao; Su, Xiaoyu; Zhao, Zhihui; Xu, Jianteng; Chen, Jie; King, Brenee; Lu, Lizhi; Tomich, John; Baybutt, Richard; Wang, Weiqun

    2014-12-01

    Weight control through either dietary calorie restriction (DCR) or exercise has been associated with cancer prevention in animal models. However, the underlying mechanisms are not fully defined. Bioinformatics using genomics, proteomics and lipidomics was employed to elucidate the molecular targets of weight control in a mouse skin cancer model. SENCAR mice were randomly assigned into four groups for 10 weeks: ad-libitum-fed sedentary control, ad-libitum-fed exercise (AE), exercise but pair-fed isocaloric amount of control (PE) and 20% DCR. Two hours after topical TPA treatment, skin epidermis was analyzed by Affymetrix for gene expression, DIGE for proteomics and lipidomics for phospholipids. Body weights were significantly reduced in both DCR and PE but not AE mice versus the control. Among 39,000 transcripts, 411, 67 and 110 genes were significantly changed in DCR, PE and AE, respectively. The expression of genes relevant to PI3K-Akt and Ras-MAPK signaling was effectively reduced by DCR and PE but not AE as measured through GenMAPP software. Proteomics analysis identified ~120 proteins, with 27 proteins significantly changed by DCR, including up-regulated apolipoprotein A-1, a key antioxidant protein that decreases Ras-MAPK activity. Of the total 338 phospholipids analyzed by lipidomics, 57 decreased by PE including 5 phophatidylinositol species that serve as PI3K substrates. Although a full impact has not been determined yet, it appears that the reduction of both Ras-MAPK and PI3K-Akt signaling pathways is a cancer preventive target that has been consistently demonstrated by three bioinformatics approaches.

  19. 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.

    Science.gov (United States)

    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.

  20. A novel synthetic Piper amide derivative NED-180 inhibits hyperpigmentation by activating the PI3K and ERK pathways and by regulating Ca2+ influx via TRPM1 channels.

    Science.gov (United States)

    Hwang, Eunson; Lee, Taek Hwan; Lee, Wook-Joo; Shim, Won-Sik; Yeo, Eui-Ju; Kim, Sanghee; Kim, Sun Yeou

    2016-01-01

    Piper amides have a characteristic, unsaturated amide group and exhibit diverse biological activities, including proliferation and differentiation of melanocytes, although the molecular mechanisms underlying its antimelanogenesis effect remain unknown. We screened a selected chemical library of newly synthesized Piper amide derivatives and identified (E)-3-(4-(tert-butyl)phenyl)-N-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)acrylamide (NED-180) as one of the most potent compounds in suppressing melanogenesis. In murine melan-a melanocytes, NED-180 downregulated the expression of melanogenic regulatory proteins including tyrosinase, Tyrp1, Dct, and MITF. PI3K/Akt-dependent phosphorylation of GSK3β by NED-180 decreases MITF phosphorylation and inhibits melanogenesis without any effects on cytotoxicity and proliferation. Furthermore, topical application of NED-180 significantly ameliorated UVB-induced skin hyperpigmentation in guinea pigs. Interestingly, data obtained using calcium imaging techniques suggested that NED-180 reduced the TPA-induced activation of TRPM1 (melastatin), which could explain the NED-180-induced inhibition of melanogenesis. All things taken together, NED-180 triggers activation of multiple pathways, such as PI3K and ERK, and inhibits TRPM1/TRPV1, leading to inhibition of melanogenesis.

  1. 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.

    Science.gov (United States)

    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.

  2. Tetramethylpyrazine Analogue CXC195 Protects Against Dopaminergic Neuronal Apoptosis via Activation of PI3K/Akt/GSK3β Signaling Pathway in 6-OHDA-Induced Parkinson's Disease Mice.

    Science.gov (United States)

    Chen, Lin; Cheng, Li; Wei, Xinbing; Yuan, Zheng; Wu, Yanmei; Wang, Shuaishuai; Ren, Zhiping; Liu, Xinyong; Liu, Huiqing

    2016-12-22

    Parkinson's disease (PD) is a progressive neurodegenerative disorder and characterized by motor system disorders resulting in loss of dopaminergic (DA) neurons. CXC195, a novel tetramethylpyrazine derivative, has been shown strongest neuroprotective effects due to its anti-apoptotic activity. However, whether CXC195 protects against DA neuronal damage in PD and the mechanisms underlying its beneficial effects are unknown. The purpose of our study was to investigate the potential neuroprotective role of CXC195 and to elucidate its mechanism of action against 6-hydroxydopamine (6-OHDA)-induced mouse model of PD. CXC195 administration improved DA neurodegeneration in PD mice induced by 6-OHDA. Our further findings confirmed treatment of CXC195 at the dose of 10 mg/kg significantly inhibited the apoptosis by decreasing the level of cleaved caspase-3 and Bax, and increasing the level of Bcl-2 in 6-OHDA-lesioned mice. Meanwhile, 6-OHDA also decreased the amount of phosphorylated Akt while increased GSK-3β activity (the amount of phosphorylated GSK-3β at Ser9 was decreased) which was prevented by CXC195. Wortmannin, a specific PI3K inhibitor, dramatically abolished the changes induced by CXC195. Our study firstly demonstrated that CXC195 protected against DA neurodegeneration in 6-OHDA-induced PD model by its anti-apoptotic properties and PI3K/Akt/GSK3β signaling pathway was involved in it.

  3. Upregulation of the PI3K/Akt pathway in the tumorigenesis of canine thyroid carcinoma

    NARCIS (Netherlands)

    Campos, M; Kool, M M J; Daminet, S; Ducatelle, R; Rutteman, G; Kooistra, H S; Galac, S; Mol, J A

    2014-01-01

    BACKGROUND: Information on the genetic events leading to thyroid cancer in dogs is lacking. HYPOTHESIS/OBJECTIVES: Upregulation of the PI3K/Akt pathway has an important role in the tumorigenesis of thyroid carcinoma in dogs. ANIMALS: Fifty-nine dogs with thyroid carcinoma and 10 healthy controls. ME

  4. The PI3K/Akt pathway contributes to arenavirus budding.

    Science.gov (United States)

    Urata, Shuzo; Ngo, Nhi; de la Torre, Juan Carlos

    2012-04-01

    Several arenaviruses, chiefly Lassa virus (LASV), cause hemorrhagic fever (HF) disease in humans and pose a significant public health concern in regions where they are endemic. On the other hand, evidence indicates that the globally distributed prototypic arenavirus lymphocytic choriomeningitis virus (LCMV) is a neglected human pathogen. The phosphatidylinositol 3-kinase (PI3K)/Akt pathway participates in many cellular processes, including cell survival and differentiation, and also has been shown to play important roles in different steps of the life cycles of a variety of viruses. Here we report that the inhibition of the PI3K/Akt pathway inhibited budding and to a lesser extent RNA synthesis, but not cell entry, of LCMV. Accordingly, BEZ-235, a PI3K inhibitor currently in cancer clinical trials, inhibited LCMV multiplication in cultured cells. These findings, together with those previously reported for Junin virus (JUNV), indicate that targeting the PI3K/Akt pathway could represent a novel antiviral strategy to combat human-pathogenic arenaviruses.

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

    Science.gov (United States)

    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.

  6. PI3K-mTOR信号通路抑制剂抗肿瘤研究新进展%Research new progress on inhibitors antitumor of PI3K-mTOR signaling pathway

    Institute of Scientific and Technical Information of China (English)

    吴松; 虞桂平; 薛涛

    2015-01-01

    PI3K is a kind of lipid kinase, controlling the cell growth, proliferation, migration, survival, angiogenesis and by activating PI3K, and AKT and mTOR to promote the development of tumor. mTOR for mammals rapamycin tar-gets is a serine/threonine protein kinase, which is widely expressed in the cell, is a kind of targeted target for the treat-ment of cancer. This paper mainly shows PI3K cancer cell line-the change of the mTOR signaling pathways, including the mechanism of action of breast cancer, prostate cancer, lung cancer, pancreatic cancer, liver cancer, etc.. PI3K-mTOR is promising targeting tumor treatment goals. Multiple targets for inhibiting tumor is the most effective method of treatment, by discussing research in clinical trials of PI3K-mTOR inhibitor drugs, for the future clinical antitumor drug research and development to provide a new way.%PI3K是一种脂质激酶,控制着细胞生长、增殖、迁移、存活和血管生成,以及通过激活磷脂酰肌醇3-激酶(PI3K)、AKT和雷帕霉素靶蛋白(mTOR)促进肿瘤发展。哺乳动物mTOR的作用靶点是一种丝氨酸/苏氨酸蛋白激酶,它在细胞中广泛地表达,是一种治疗癌症的靶向目标。本文将主要论述癌症细胞系PI3K-mTOR信号通路的改变,包括乳腺癌、前列腺癌、肺癌、胰腺癌、肝癌等的作用机制。 PI3K-mTOR是肿瘤治疗的有前途的靶向目标。多靶点抑制是肿瘤治疗最有效的方法,通过讨论临床试验中研究的PI3K-mTOR抑制剂药物,为将来临床抗肿瘤药物的研发提供新途径。

  7. Tiam1 mediates Ras activation of Rac by a PI(3)K-independent mechanism.

    Science.gov (United States)

    Lambert, John M; Lambert, Que T; Reuther, Gary W; Malliri, Angeliki; Siderovski, David P; Sondek, John; Collard, John G; Der, Channing J

    2002-08-01

    Rac is a member of the Ras superfamily of GTPases and functions as a GDP/GTP-regulated switch. Formation of active Rac-GTP is stimulated by Dbl family guanine nucleotide exchange factors (GEFs), such as Tiam1 (ref. 2). Once activated, Rac stimulates signalling pathways that regulate actin organization, gene expression and cellular proliferation. Rac also functions downstream of the Ras oncoprotein in pathways that stimulate membrane ruffling, growth transformation, activation of the c-Jun amino-terminal kinase (JNK) mitogen-activated protein kinase, activation of the NF-kappa B transcription factor and promotion of cell survival. Although recent studies support phosphatidylinositol 3-OH kinase (PI(3)K)-dependent mechanisms through which Ras might activate Rac (refs 9,10), the precise mechanism remains to be determined. Here we demonstrate that Tiam1, a Rac-specific GEF, preferentially associates with activated GTP-bound Ras through a Ras-binding domain. Furthermore, activated Ras and Tiam1 cooperate to cause synergistic formation of Rac-GTP in a PI(3)K-independent manner. Thus, Tiam1 can function as an effector that directly mediates Ras activation of Rac.

  8. In vitro antiproliferative activity of 2,3-dihydroxy-9,10-anthraquinone induced apoptosis against COLO320 cells through cytochrome c release caspase mediated pathway with PI3K/AKT and COX-2 inhibition.

    Science.gov (United States)

    Balachandran, C; Emi, N; Arun, Y; Yamamoto, N; Duraipandiyan, V; Inaguma, Yoko; Okamoto, Akinao; Ignacimuthu, S; Al-Dhabi, N A; Perumal, P T

    2016-04-05

    The present study investigated the anticancer activity of 2,3-dihydroxy-9,10-anthraquinone against different cancer cells such as MCF-7, COLO320, HepG-2, Skov-3, MOLM-14, NB-4, CEM, K562, Jurkat, HL-60, U937, IM-9 and Vero. 2,3-dihydroxy-9,10-anthraquinone showed good antiproliferative activity against COLO320 cells when compared to other tested cells. The cytotoxicity results showed 79.8% activity at the dose of 2.07 μM with IC50 value of 0.13 μM at 24 h in COLO320 cells. So we chose COLO320 cells for further anticancer studies. mRNA expression was confirmed by qPCR analysis using SYBR green method. Treatment with 2,3-dihydroxy-9,10-anthraquinone was found to trigger intrinsic apoptotic pathway as indicated by down regulation of Bcl-2, Bcl-xl; up regulation of Bim, Bax, Bad; release of cytochrome c and pro-caspases cleaving to caspases. Furthermore, 2,3-dihydroxy-9,10-anthraquinone stopped at G0/G1 phase with modulation in protein levels of cyclins. On the other hand PI3K/AKT signaling plays an important role in cell metabolism. We found that 2,3-dihydroxy-9,10-anthraquinone inhibits PI3K/AKT activity after treatment. Also, COX-2 enzyme plays a major role in colorectal cancer. Our results showed that the treatment significantly reduced COX-2 enzyme in COLO320 cells. These results indicated antiproliferative activity of 2,3-dihydroxy-9,10-anthraquinone involving apoptotic pathways, mitochondrial functions, cell cycle checkpoint and controlling the over expression genes during the colorectal cancer. Molecular docking studies showed that the compound bound stably to the active sites of Bcl-2, COX-2, PI3K and AKT. This is the first report of anticancer mechanism involving 2,3-dihydroxy-9,10-anthraquinone in COLO320 cells. The present results might provide helpful suggestions for the design of antitumor drugs toward colorectal cancer treatment. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  9. Co-Targeting the PI3K and RAS Pathways for the Treatment of Neuroendocrine Tumors

    Science.gov (United States)

    Valentino, Joseph D.; Li, Jing; Zaytseva, Yekaterina Y.; Mustain, W. Conan; Elliott, Victoria A.; Kim, Ji Tae; Harris, Jennifer W.; Campbell, Katherine; Weiss, Heidi; Wang, Chi; Song, Jun; Anthony, Lowell; Townsend, Courtney M.; Evers, B. Mark

    2014-01-01

    Background The precise involvement of the PI3K/mTOR and RAS/MEK pathways in carcinoid tumors is not well defined. Therefore, the purpose of our study was to evaluate the role these pathways play in carcinoid cell proliferation, apoptosis, and secretion and to determine the effects of combined treatment on carcinoid tumor inhibition. Methods The human neuroendocrine cell lines BON (pancreatic carcinoid), NCI-H727 (lung carcinoid), and QGP-1 (somatostatinoma) were treated with either the pan-PI3K inhibitor, BKM120, or the dual PI3K-mTOR inhibitor, BEZ235, alone or in combination with the MEK inhibitor, PD0325901; proliferation, apoptosis, and protein expression were assessed. Peptide secretion was evaluated in BON and QGP-1 cells. The anti-proliferative effect of BEZ235, alone or combined with PD0325901, was then tested in vivo. Results Both BKM120 and BEZ235 decreased proliferation and increased apoptosis; combination with PD0325901 significantly enhanced the antineoplastic effects of either treatment alone. In contrast, neurotensin (NT) peptide secretion was markedly stimulated with BKM120 treatment, but not BEZ235. The combination of BEZ235 + PD0325901 significantly inhibited the growth of BON xenografts without systemic toxicity. Conclusions Both BKM120 and BEZ235 effectively inhibited NET cell proliferation and stimulated apoptosis. However, inhibition of the PI3K pathway alone with BKM120 significantly stimulated NT peptide secretion; this did not occur with the dual inhibition of both PI3K and mTOR using BEZ235 suggesting that this would be a more effective treatment regimen for NETs. Moreover, the combination of BEZ235 and the MEK inhibitor PD0325901 was a safe and more effective therapy in vivo compared with single agents alone. PMID:24443523

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

    Directory of Open Access Journals (Sweden)

    Amir M Hossini

    Full Text Available 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.

  11. 13-Acetoxysarcocrassolide Induces Apoptosis on Human Gastric Carcinoma Cells Through Mitochondria-Related Apoptotic Pathways: p38/JNK Activation and PI3K/AKT Suppression

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    Ching-Chyuan Su

    2014-10-01

    Full Text Available 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.

  12. The phytoestrogen ginsensoside Re activates potassium channels of vascular smooth muscle cells through PI3K/Akt and nitric oxide pathways.

    Science.gov (United States)

    Nakaya, Yutaka; Mawatari, Kazuaki; Takahashi, Akira; Harada, Nagakatsu; Hata, Akiko; Yasui, Sonoko

    2007-08-01

    In vascular smooth muscle cells, large-conductance Ca(2+)-activated K(+) channels (K(Ca) channels) play a pivotal role in determining membrane potential, and thereby the vascular tone. Ginsenoside Re, a phytochemical from ginseng, is reported to activate this channel, but its precise mechanism is unsolved. Patch clamp studies showed that ginsenoside Re activates K(Ca) channels in the arterial smooth muscle cell line A10 in a dose-dependent manner. The channel-opening effect of ginsenoside Re was inhibited by 1 microM L-NIO, an inhibitor of eNOS, but not by 3 microM SMTC, an inhibitor of nNOS, indicating that ginsenoside Re activated K(Ca) channels through activation of eNOS. SH-6 (10 microM), an Akt inhibitor, and wortmannin, a PI3-kinase inhibitor, completely blocked activation of K(Ca) channels by ginsenoside Re, indicating that it activates eNOS via a c-Src/PI3-kinase/Akt-dependent mechanism. In addition, the ginsenoside Re-induced activation of eNOS and K(Ca) channel was blocked by 10 microM ICI 182, 780, an inhibitor of membrane estrogen receptor-alpha, suggesting that eNOS activation occurs via a non-genomic pathway of this receptor. In conclusion, ginsenoside Re releases NO via a membrane sex steroid receptors, resulting in K(Ca) channel activation in vascular smooth muscle cells, promoting vasodilation and preventing severe arterial contraction.

  13. Over-production of nitric oxide by oxidative stress-induced activation of the TGF-β1/PI3K/Akt pathway in mesangial cells cultured in high glucose

    Institute of Scientific and Technical Information of China (English)

    Yun-peng ZHAI; Qian LU; Yao-wu LIU; Qian CHENG; Ya-qin WEI; Fan ZHANG; Cheng-lin LI

    2013-01-01

    Aim:To investigate whether NO over-production in rat mesangial cells cultured in high glucose (HG) is related to activation of the TGF-β1/PI3K/Akt pathway.Methods:Rat mesangial cells line (HBZY-1) was exposed to HG (24.44 mmol/L) or H2O2 (10 μmol/L) for 16 h.NO release was quantified using the Griess assay.The TGF-β1 level was measured using ELISA.The protein expression of p-Akt,t-Akt,Bim,and iNOS was examined by Western blotting.The mRNA levels of TGF-β1 and Bim were measured using RT-PCR.The cell proliferation rate was estimated using a BrdU incorporation assay.Results:Treatment of the cells with HG,H2O2,or TGF-β1 (5 ng/mL) significantly increased the NO level that was substantially inhibited by co-treatment with the NADPH oxidase inhibitor diphenylene iodonium (DPI),TGF-β1 inhibitor SB431542,or PI3K inhibitor LY294002.Both HG and H2O2 significantly increased the protein and mRNA levels of TGF-β1 in the cells,and HG-induced increases of TGF-β1 protein and mRNA were blocked by co-treatment with DPI.Furthermore,the treatment with HG or H2O2 significantly increased the expression of phosphorylated Akt and iNOS and cell proliferation rate,which was blocked by co-treatment with DPI,SB431542,or LY294002.Moreover,the treatment with HG or H2O2 significantly inhibited Bim protein and mRNA expression,which was reversed by co-treatment with DPI,SB431542,or LY294002.Conclusion:The results demonstrate that high glucose causes oxidative stress and NO over-production in rat mesangial cells in vitro via decreasing Bim and increasing iNOS,which are at least partially mediated by the TGF-β1/PI3K/Akt pathway.

  14. AKTivation of the PI3K/AKT/mTOR signaling pathway by KSHV

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    Aadra P Bhatt

    2013-01-01

    Full Text Available As an obligate intracellular parasite, the Kaposi sarcoma-associated herpesvirus (KSHV relies on host cell machinery to meet its needs for survival, viral replication, production, and dissemination of progeny virions. KSHV is a ɣ-herpesvirus that is associated with three different malignancies: Kaposi sarcoma (KS, and two B cell lymphoproliferative disorders, primary effusion lymphoma (PEL and multicentric Castleman disease (MCD. KSHV viral proteins modulate cellular phosphatidylinositol-3-kinase (PI3K/AKT/mammalian target of rapamycin (mTOR signaling pathway, which is a ubiquitous pathway that also controls B lymphocyte proliferation and development. We review the mechanisms by which KSHV manipulates the PI3K/AKT/mTOR pathway, with a specific focus on B cells.

  15. Oxidized ATM promotes abnormal proliferation of breast CAFs through maintaining intracellular redox homeostasis and activating the PI3K-AKT, MEK-ERK, and Wnt-β-catenin signaling pathways.

    Science.gov (United States)

    Tang, Shifu; Hou, Yixuan; Zhang, Hailong; Tu, Gang; Yang, Li; Sun, Yifan; Lang, Lei; Tang, Xi; Du, Yan-E; Zhou, Mingli; Yu, Tenghua; Xu, Liyun; Wen, Siyang; Liu, Chunming; Liu, Manran

    2015-01-01

    Abnormal proliferation is one characteristic of cancer-associated fibroblasts (CAFs), which play a key role in tumorigenesis and tumor progression. Oxidative stress (OS) is the root cause of CAFs abnormal proliferation. ATM (ataxia-telangiectasia mutated protein kinase), an important redox sensor, is involved in DNA damage response and cellular homeostasis. Whether and how oxidized ATM regulating CAFs proliferation remains unclear. In this study, we show that there is a high level of oxidized ATM in breast CAFs in the absence of double-strand breaks (DSBs) and that oxidized ATM plays a critical role in CAFs proliferation. The effect of oxidized ATM on CAFs proliferation is mediated by its regulation of cellular redox balance and the activity of the ERK, PI3K-AKT, and Wnt signaling pathways. Treating cells with antioxidant N-acetyl-cysteine (NAC) partially rescues the proliferation defect of the breast CAFs caused by ATM deficiency. Administrating cells with individual or a combination of specific inhibitors of the ERK, PI3K-AKT, and Wnt signaling pathways mimics the effect of ATM deficiency on breast CAF proliferation. This is mainly ascribed to the β-catenin suppression and down-regulation of c-Myc, thus further leading to the decreased cyclinD1, cyclinE, and E2F1 expression and the enhanced p21(Cip1) level. Our results reveal an important role of oxidized ATM in the regulation of the abnormal proliferation of breast CAFs. Oxidized ATM could serve as a potential target for treating breast cancer.

  16. Insulin relaxes bladder via PI3K/AKT/eNOS pathway activation in mucosa: unfolded protein response-dependent insulin resistance as a cause of obesity-associated overactive bladder

    Science.gov (United States)

    Leiria, Luiz O; Sollon, Carolina; Báu, Fernando R; Mónica, Fabíola Z; D’Ancona, Carlos L; De Nucci, Gilberto; Grant, Andrew D; Anhê, Gabriel F; Antunes, Edson

    2013-01-01

    We aimed to investigate the role of insulin in the bladder and its relevance for the development of overactive bladder (OAB) in insulin-resistant obese mice. Bladders from male individuals who were involved in multiple organ donations were used. C57BL6/J mice were fed with a high-fat diet for 10 weeks to induce insulin-resistant obesity. Concentration–response curves to insulin were performed in human and mouse isolated mucosa-intact and mucosa-denuded bladders. Cystometric study was performed in terminally anaesthetized mice. Western blot was performed in bladders to detect phosphorylated endothelial NO synthase (eNOS) (Ser1177) and the phosphorylated protein kinase AKT (Ser473), as well as the unfolded protein response (UPR) markers TRIB3, CHOP and ATF4. Insulin (1–100 nm) produced concentration-dependent mouse and human bladder relaxations that were markedly reduced by mucosal removal or inhibition of the PI3K/AKT/eNOS pathway. In mouse bladders, insulin produced a 3.0-fold increase in cGMP levels (P insulin-induced phosphorylation of AKT and eNOS in bladder mucosa. Obese mice showed greater voiding frequency and non-voiding contractions, indicating overactive detrusor smooth muscle. Insulin failed to relax the bladder or to increase cGMP in the obese group. Insulin-stimulated AKT and eNOS phosphorylation in mucosa was also impaired in obese mice. The UPR markers TRIB3, CHOP and ATF4 were increased in the mucosa of obese mice. The UPR inhibitor 4-phenyl butyric acid normalized all the functional and molecular parameters in obese mice. Our data show that insulin relaxes human and mouse bladder via activation of the PI3K/AKT/eNOS pathway in the bladder mucosa. Endoplasmic reticulum stress-dependent insulin resistance in bladder contributes to OAB in obese mice. PMID:23478138

  17. Simultaneous perturbation of the MAPK and the PI3K/mTOR pathways does not lead to increased radiosensitization

    OpenAIRE

    Kuger, Sebastian; Flentje, Michael; Djuzenova, Cholpon S.

    2016-01-01

    Background The mitogen-activated protein kinases (MAPK) and the phosphatidylinositol-3-kinase (PI3K)/mammalian target of rapamycin (mTOR) pathways are intertwined on various levels and simultaneous inhibition reduces tumorsize and prolonges survival synergistically. Furthermore, inhibiting these pathways radiosensitized cancer cells in various studies. To assess, if phenotypic changes after perturbations of this signaling network depend on the genetic background, we integrated a time series o...

  18. The Biological Role of PI3K Pathway in Lung Cancer

    Directory of Open Access Journals (Sweden)

    Kostas N. Syrigos

    2012-11-01

    Full Text Available Lung cancer is the primary cause of cancer-related mortality worldwide and although improvements in treatment have been achieved over the last few years, long-term survival rates for lung cancer patients remain poor. Therefore, there is an imperative need for molecularly targeted agents that will achieve long-term disease control. Numerous downstream molecular pathways, such as EGF/RAS/RAF/MEK/ERK and PI3K/AKT/mTOR are identified as having a key role in the pathogenesis of various forms of human cancer, including lung cancer. PI3K/AKT/mTOR signal pathway is an important intracellular signal transduction pathway with a significant role in cell proliferation, growth, survival, vesicle trafficking, glucose transport, and cytoskeletal organization. Aberrations in many primary and secondary messenger molecules of this pathway, including mutations and amplifications, are accounted for tumor cell proliferation, inhibition of apoptosis, angiogenesis, metastasis and resistance to chemotherapy-radiotherapy. In this review article, we investigate thoroughly the biological role of PI3K pathway in lung cancer and its contribution in the development of future therapeutic strategies.

  19. α-Lipoic acid reduces infarct size and preserves cardiac function in rat myocardial ischemia/reperfusion injury through activation of PI3K/Akt/Nrf2 pathway.

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    Chao Deng

    Full Text Available BACKGROUND: The present study investigates the effects and mechanisms of α-Lipoic acid (LA on myocardial infarct size, cardiac function and cardiomyocyte apoptosis in rat hearts subjected to in vivo myocardial ischemia/reperfusion (MI/R injury. METHODOLOGY/PRINCIPAL FINDINGS: Male adult rats underwent 30 minutes of ischemia followed by 3, 24, or 72 h of reperfusion. Animals were pretreated with LA or vehicle before coronary artery ligation. The level of MI/R- induced LDH and CK release, infarct size, cardiomyocyte apoptosis and cardiac functional impairment were examined and compared. Western blot analysis was performed to elucidate the mechanism of LA pretreatment. The level of inflammatory cytokine TNF-α released to serum and accumulated in injured myocardium as well as neutrophil accumulation in injured myocardium were also examined after MI/R injury. Our results reveal that LA administration significantly reduced LDH and CK release, attenuated myocardial infarct size, decreased cardiomyocytes apoptosis, and partially preserved heart function. Western blot analysis showed that LA pretreatment up-regulated Akt phosphorylation and Nrf2 nuclear translocation while producing no impact on p38MAPK activation or nitric oxide (NO production. LA pretreatment also increased expression of HO-1, a major target of Nrf2. LA treatment inhibited neutrophil accumulation and release of TNF-α. Moreover, PI3K inhibition abolished the beneficial effects of LA. CONCLUSIONS/SIGNIFICANCE: This study indicates that LA attenuates cardiac dysfunction by reducing cardiomyoctyes necrosis, apoptosis and inflammation after MI/R. LA exerts its action by activating the PI3K/Akt pathway as well as subsequent Nrf2 nuclear translocation and induction of cytoprotective genes such as HO-1.

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

    Science.gov (United States)

    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.

  1. High expression of G-protein signaling modulator 2 in hepatocellular carcinoma facilitates tumor growth and metastasis by activating the PI3K/AKT signaling pathway.

    Science.gov (United States)

    He, Xiao-Qin; Zhang, Yue-Feng; Yu, Jia-Jun; Gan, Yuan-Yuan; Han, Na-Na; Zhang, Mei-Xia; Ge, Wei; Deng, Jun-Jian; Zheng, Yong-Fa; Xu, Xi-Ming

    2017-03-01

    The aim of this study was to investigate the role of G-protein signaling modulator 2 in the carcinogenesis and progression of hepatocellular carcinoma. We previously showed that G-protein signaling modulator 2 was upregulated in hepatitis B virus-related hepatocellular carcinoma tissues through a hierarchical clustering analysis. With this study, we first assessed the expression pattern of G-protein signaling modulator 2 in hepatocellular carcinoma specimens and adjacent noncancerous tissues; clinical data were analyzed, along survival times, utilizing the Kaplan-Meier method. Moreover, the functions of G-protein signaling modulator 2 were examined using small-interfering RNAs in vitro. The results showed that G-protein signaling modulator 2 was clearly overexpressed in hepatocellular carcinoma tissues and cell lines and that the G-protein signaling modulator 2 expression level was related to tumor size and hepatitis B virus infection. Furthermore, G-protein signaling modulator 2 knockdown studies suggested that G-protein signaling modulator 2 accelerates cell growth, cell cycle, migration, and invasion and inhibits apoptosis, acting as an oncogene in hepatocellular carcinoma. Western blotting indicated that silencing of G-protein signaling modulator 2 in HepG2 and SMMC-7721 cells increased the expression levels of Bax, caspase-3, and E-cadherin, while notably suppressing the cyclin-dependent kinase 4, cyclin-dependent kinase 6, CyclinD1, Snail1, Vimentin, and matrix metallopeptidase 9 expression levels, compared with that in the control groups. In addition, we found that G-protein signaling modulator 2 can affect the expression of key proteins involved in protein kinase B activation. In conclusion, high expression of G-protein signaling modulator 2 was involved in the pathological processes of hepatocellular carcinoma through activation of the phosphatidylinositol 3-kinase/protein kinase B signaling pathway, which may provide an attractive potential diagnostic

  2. A New Therapeutic Modality for Acute Myocardial Infarction: Nanoparticle-Mediated Delivery of Pitavastatin Induces Cardioprotection from Ischemia-Reperfusion Injury via Activation of PI3K/Akt Pathway and Anti-Inflammation in a Rat Model.

    Directory of Open Access Journals (Sweden)

    Kazuhiro Nagaoka

    Full Text Available There is an unmet need to develop an innovative cardioprotective modality for acute myocardial infarction (AMI, for which the effectiveness of interventional reperfusion therapy is hampered by myocardial ischemia-reperfusion (IR injury. Pretreatment with statins before ischemia is shown to reduce MI size in animals. However, no benefit was found in animals and patients with AMI when administered at the time of reperfusion, suggesting insufficient drug targeting into the IR myocardium. Here we tested the hypothesis that nanoparticle-mediated targeting of pitavastatin protects the heart from IR injury.In a rat IR model, poly(lactic acid/glycolic acid (PLGA nanoparticle incorporating FITC accumulated in the IR myocardium through enhanced vascular permeability, and in CD11b-positive leukocytes in the IR myocardium and peripheral blood after intravenous treatment. Intravenous treatment with PLGA nanoparticle containing pitavastatin (Pitavastatin-NP, 1 mg/kg at reperfusion reduced MI size after 24 hours and ameliorated left ventricular dysfunction 4-week after reperfusion; by contrast, pitavastatin alone (as high as 10 mg/kg showed no therapeutic effects. The therapeutic effects of Pitavastatin-NP were blunted by a PI3K inhibitor wortmannin, but not by a mitochondrial permeability transition pore inhibitor cyclosporine A. Pitavastatin-NP induced phosphorylation of Akt and GSK3β, and inhibited inflammation and cardiomyocyte apoptosis in the IR myocardium.Nanoparticle-mediated targeting of pitavastatin induced cardioprotection from IR injury by activation of PI3K/Akt pathway and inhibition of inflammation and cardiomyocyte death in this model. This strategy can be developed as an innovative cardioprotective modality that may advance currently unsatisfactory reperfusion therapy for AMI.

  3. PD-L1 promotes OCT4 and Nanog expression in breast cancer stem cells by sustaining PI3K/AKT pathway activation.

    Science.gov (United States)

    Almozyan, Sheema; Colak, Dilek; Mansour, Fatmah; Alaiya, Ayodele; Al-Harazi, Olfat; Qattan, Amal; Al-Mohanna, Falah; Al-Alwan, Monther; Ghebeh, Hazem

    2017-10-01

    The expression of PD-L1 in breast cancer is associated with estrogen receptor negativity, chemoresistance and epithelial-to-mesenchymal transition (EMT), all of which are common features of a highly tumorigenic subpopulation of cancer cells termed cancer stem cells (CSCs). Hitherto, the expression and intrinsic role of PD-L1 in the dynamics of breast CSCs has not been investigated. To address this issue, we used transcriptomic datasets, proteomics and several in vitro and in vivo assays. Expression profiling of a large breast cancer dataset (530 patients) showed statistically significant correlation (p cancer. Specific knockdown of PD-L1 using ShRNA revealed its critical role in the expression of the embryonic stem cell transcriptional factors: OCT-4A, Nanog and the stemness factor, BMI1. Conversely, these factors could be induced upon PD-L1 ectopic expression in cells that are normally PD-L1 negative. Global proteomic analysis hinted for the central role of AKT in the biology of PD-L1 expressing cells. Indeed, PD-L1 positive effect on OCT-4A and Nanog was dependent on AKT activation. Most importantly, downregulation of PD-L1 compromised the self-renewal capability of breast CSCs in vitro and in vivo as shown by tumorsphere formation assay and extreme limiting dilution assay, respectively. This study demonstrates a novel role for PD-L1 in sustaining stemness of breast cancer cells and identifies the subpopulation and its associated molecular pathways that would be targeted upon anti-PD-L1 therapy. © 2017 The Authors International Journal of Cancer published by John Wiley & Sons Ltd on behalf of UICC.

  4. PI3K/PTEN/Akt and TSC/mTOR signaling pathways, ovarian dysfunction, and infertility: an update.

    Science.gov (United States)

    Makker, Annu; Goel, Madhu Mati; Mahdi, Abbas Ali

    2014-12-01

    Abnormalities in ovarian function, including defective oogenesis and folliculogenesis, represent a key female reproductive deficiency. Accumulating evidence in the literature has shown that the PI3K/PTEN/Akt and TSC/mTOR signaling pathways are critical regulators of ovarian function including quiescence, activation, and survival of primordial follicles, granulosa cell proliferation and differentiation, and meiotic maturation of oocytes. Dysregulation of these signaling pathways may contribute to infertility caused by impaired follicular development, intrafollicular oocyte development, and ovulation. This article reviews the current state of knowledge of the functional role of the PI3K/PTEN/Akt and TSC/mTOR pathways during mammalian oogenesis and folliculogenesis and their association with female infertility.

  5. VEGFA upregulates FLJ10540 and modulates migration and invasion of lung cancer via PI3K/AKT pathway.

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    Chang-Han Chen

    Full Text Available BACKGROUND: Lung adenocarcinoma is the leading cause of cancer-related deaths among both men and women in the world. Despite recent advances in diagnosis and treatment, the mortality rates with an overall 5-year survival of only 15%. This high mortality is probably attributable to early metastasis. Although several well-known markers correlated with poor/metastasis prognosis in lung adenocarcinoma patients by immunohistochemistry was reported, the molecular mechanisms of lung adenocarcinoma development are still not clear. To explore novel molecular markers and their signaling pathways will be crucial for aiding in treatment of lung adenocarcinoma patients. METHODOLOGY/PRINCIPAL FINDINGS: To identify novel lung adenocarcinoma-associated /metastasis genes and to clarify the underlying molecular mechanisms of these targets in lung cancer progression, we created a bioinformatics scheme consisting of integrating three gene expression profile datasets, including pairwise lung adenocarcinoma, secondary metastatic tumors vs. benign tumors, and a series of invasive cell lines. Among the novel targets identified, FLJ10540 was overexpressed in lung cancer tissues and is associated with cell migration and invasion. Furthermore, we employed two co-expression strategies to identify in which pathway FLJ10540 was involved. Lung adenocarcinoma array profiles and tissue microarray IHC staining data showed that FLJ10540 and VEGF-A, as well as FLJ10540 and phospho-AKT exhibit positive correlations, respectively. Stimulation of lung cancer cells with VEGF-A results in an increase in FLJ10540 protein expression and enhances complex formation with PI3K. Treatment with VEGFR2 and PI3K inhibitors affects cell migration and invasion by activating the PI3K/AKT pathway. Moreover, knockdown of FLJ10540 destabilizes formation of the P110-alpha/P85-alpha-(PI3K complex, further supporting the participation of FLJ10540 in the VEGF-A/PI3K/AKT pathway. CONCLUSIONS

  6. Gypenoside Protects against Myocardial Ischemia-Reperfusion Injury by Inhibiting Cardiomyocytes Apoptosis via Inhibition of CHOP Pathway and Activation of PI3K/Akt Pathway In Vivo and In Vitro

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    Haijie Yu

    2016-06-01

    Full Text Available Background/Aims: Ischemia-reperfusion (I/R injury is believed to be the major cause for detriments in coronary heart diseases, but few effective therapies for prevention or treatment of I/R injury are available. Gypenoside (GP is the predominant effective component of Gynostemma pentaphyllum and possesses capacities against inflammation and oxidation. In the present study, the role of GP in ameliorating myocardial I/R injury was investigated. Methods: effect GP on the cardiac structure of I/R injured rats was assessed by H&E and TTC staining. Then the influence of GP on the cardiac function of rat model was determined by measuring hemodynamics parameters, levels of lactate dehydrogenase (LDH and creatine kinase (CK. Thereafter, effect of GP on apoptotic process was evaluated with both rat and cell models. The production of molecules related to ER stress and apoptosis was quantified for revelation of pathways involved in the myocardial protective effect of GP. Results: Impairments in cardiac structure due to I/R injury was ameliorated by GP treatment. And it was evidently demonstrated that administration of GP not only effectively decreased the apoptotic rates in both rat and cell models but also markedly improved the cardiac function of I/R injured rats. In addition, results of western blotting revealed that the GP inhibited ER-stress and apoptosis through the blockade of CHOP pathway and activation of PI3K/Akt pathway. Conclusion: the current study showed the potential of GP to alleviate myocardial I/R injury and preliminarily uncovered the underling mechanism driving this treatment.

  7. Momordin Ic induces HepG2 cell apoptosis through MAPK and PI3K/Akt-mediated mitochondrial pathways.

    Science.gov (United States)

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

    2013-06-01

    Momordin Ic is a natural triterpenoid saponin enriched in various Chinese and Japanese natural medicines such as the fruit of Kochia scoparia (L.) Schrad. So far, there is little scientific evidence for momordin Ic with regard to the anti-tumor activities. The aim of this work was to elucidate the anti-tumor effect of momordin Ic and the signal transduction pathways involved. We found that momordin Ic induced apoptosis in human hepatocellular carcinoma HepG2 cells, which were supported by DNA fragmentation, caspase-3 activation and PARP cleavage. Meanwhile, momordin Ic triggered reactive oxygen species (ROS) production together with collapse of mitochondrial membrane potential, cytochrome c release, down-regulation of Bcl-2 and up-regulation of Bax expression. The activation of p38 and JNK, inactivation of Erk1/2 and Akt were also demonstrated. Although ROS production rather than NO was stimulated, the expression of iNOS and HO-1 were altered after momordin Ic treatment for 4 h. Furthermore, the cytochrome c release, caspase-3 activation, Bax/Bcl-2 expression and PARP cleavage were promoted with LY294002 and U0126 intervention but were blocked by SB203580, SP600125, PI3K activator, NAC and 1,400 W pretreatment, demonstrating the mitochondrial disruption. Furthermore, momordin Ic combination with NAC influenced MAPK, PI3K/Akt and HO-1, iNOS pathways, MAPK and PI3K/Akt pathways also regulated the expression of HO-1 and iNOS. These results indicated that momordin Ic induced apoptosis through oxidative stress-regulated mitochondrial dysfunction involving the MAPK and PI3K-mediated iNOS and HO-1 pathways. Thus, momordin Ic might represent a potential source of anticancer candidate.

  8. Salidroside ameliorates insulin resistance through activation of a mitochondria-associated AMPK/PI3K/Akt/GSK3[beta] pathway

    National Research Council Canada - National Science Library

    Tao Zheng; Xiaoyan Yang; Dan Wu; Shasha Xing; Fang Bian; Wenjing Li; Jiangyang Chi; Xiangli Bai; Guangjie Wu; Xiaoqian Chen; Yonghui Zhang; Si Jin

    2015-01-01

      Background and Purpose Recent reports have suggested that salidroside could protect cardiomyocytes from oxidative injury and stimulate glucose uptake in skeletal muscle cells by activating AMP-activated protein kinase (AMPK...

  9. Synergistic effects of concurrent blockade of PI3K and MEK pathways in pancreatic cancer preclinical models.

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    Hua Zhong

    Full Text Available Patients with pancreatic cancer have dismal prognoses, and novel therapies are urgently needed. Mutations of the KRAS oncogene occur frequently in pancreatic cancer and represent an attractive target. Direct targeting of the predominant KRAS pathways have been challenging and research into therapeutic strategies have been now refocused on pathways downstream of KRAS, phosphoinositide 3-kinase (PI3K and mitogen-activated protein kinase (MAPK [MEK]. We hypothesized that concurrent inhibition of the PI3K and MEK pathways would result in synergistic antitumor activity, as it would circumvent the compensatory feedback loop between the two pathways. We investigated the combined effect of the PI3K inhibitor, GDC0941, and the MEK inhibitor, AZD6244, on cell viability, apoptosis and cell signaling in a panel of pancreatic cancer cell lines. An in vivo analysis was conducted on pancreatic cancer xenografts. While BxPC-3 (KRAS wild type and MIA PaCa-2 (KRAS mutated cell lines were sensitive to GDC0941 and AZD6244 as single agents, synergistic inhibition of tumor cell growth and induction of apoptosis were observed in both cell lines when the two drugs were combined. Interestingly, phosphorylation of the cap-dependent translational components, 4E-binding protein (p-4E-BP1 and S6 was found to be closely associated with sensitivity to GDC0941 and AZD6244. In BxPC-3 cell xenografts, survival differences were observed between the control and the AZD6244, GDC0941, and combination groups. Our study provides the rationale for concurrent targeting of the PI3K and MEK pathways, regardless of KRAS status, and suggests that phosphorylation of 4E-BP1and S6 can serve as a predictive biomarker for response to treatment.

  10. N-carbamylglutamate enhances pregnancy outcome in rats through activation of the PI3K/PKB/mTOR signaling pathway.

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    Xiangfang Zeng

    Full Text Available Administration of N-carbamylglutamate (NCG, an analogue of endogenous N-acetyl-glutamate (an activator of arginine synthesis has been shown to enhance neonatal growth by increasing circulating arginine levels. However, the effect of NCG on pregnancy remains unknown. This study examined the effects of NCG on pregnancy outcome and evaluated potential mechanisms involved. Reproductive performance, embryo implantation, and concentration of amino acids in serum and uterine flushing, were determined in rats fed control or NCG supplemented diets. Ishikawa cells and JAR cells were used to examine the mechanism by which NCG affects embryo implantation. Dietary NCG supplementation increased serum levels of arginine, onithine, and proline, as well as uterine levels of arginine, glutamine, glutamate, and proline. Additionally, it stimulated LIF expression, and enhanced the activation of signal transduction and activator of transcription 3 (Stat3, protein kinase B (PKB, and 70-kDa ribosomal protein S6 kinase (S6K1 during the periimplantation period, resulting in an increase in litter size but not birth weight. In uterine Ishikawa cells, LIF expression was also enhanced by treatment with arginine and its metabolites. In trophoblast JAR cells, treatment with arginine and its metabolites enhanced Stat3, PKB, and S6K1 activation and facilitated cellular adhesion activity. These effects were abolished by pretreatment with inhibitors of phosphatidylinositol 3-kinase (wortmannin and mammalian target of rapamycin (rapamycin. The results demonstrate that NCG supplementation enhances pregnancy outcome and have important implications for the pregnancy outcome of mammalian species.

  11. N-carbamylglutamate enhances pregnancy outcome in rats through activation of the PI3K/PKB/mTOR signaling pathway.

    Science.gov (United States)

    Zeng, Xiangfang; Huang, Zhimin; Mao, Xiangbing; Wang, Junjun; Wu, Guoyao; Qiao, Shiyan

    2012-01-01

    Administration of N-carbamylglutamate (NCG), an analogue of endogenous N-acetyl-glutamate (an activator of arginine synthesis) has been shown to enhance neonatal growth by increasing circulating arginine levels. However, the effect of NCG on pregnancy remains unknown. This study examined the effects of NCG on pregnancy outcome and evaluated potential mechanisms involved. Reproductive performance, embryo implantation, and concentration of amino acids in serum and uterine flushing, were determined in rats fed control or NCG supplemented diets. Ishikawa cells and JAR cells were used to examine the mechanism by which NCG affects embryo implantation. Dietary NCG supplementation increased serum levels of arginine, onithine, and proline, as well as uterine levels of arginine, glutamine, glutamate, and proline. Additionally, it stimulated LIF expression, and enhanced the activation of signal transduction and activator of transcription 3 (Stat3), protein kinase B (PKB), and 70-kDa ribosomal protein S6 kinase (S6K1) during the periimplantation period, resulting in an increase in litter size but not birth weight. In uterine Ishikawa cells, LIF expression was also enhanced by treatment with arginine and its metabolites. In trophoblast JAR cells, treatment with arginine and its metabolites enhanced Stat3, PKB, and S6K1 activation and facilitated cellular adhesion activity. These effects were abolished by pretreatment with inhibitors of phosphatidylinositol 3-kinase (wortmannin) and mammalian target of rapamycin (rapamycin). The results demonstrate that NCG supplementation enhances pregnancy outcome and have important implications for the pregnancy outcome of mammalian species.

  12. iTRAQ proteomics analysis reveals that PI3K is highly associated with bupivacaine-induced neurotoxicity pathways.

    Science.gov (United States)

    Zhao, Wei; Liu, Zhongjie; Yu, Xujiao; Lai, Luying; Li, Haobo; Liu, Zipeng; Li, Le; Jiang, Shan; Xia, Zhengyuan; Xu, Shi-yuan

    2016-02-01

    Bupivacaine, a commonly used local anesthetic, has potential neurotoxicity through diverse signaling pathways. However, the key mechanism of bupivacaine-induced neurotoxicity remains unclear. Cultured human SH-SY5Y neuroblastoma cells were treated (bupivacaine) or untreated (control) with bupivacaine for 24 h. Compared to the control group, bupivacaine significantly increased cyto-inhibition, cellular reactive oxygen species, DNA damage, mitochondrial injury, apoptosis (increased TUNEL-positive cells, cleaved caspase 3, and Bcl-2/Bax), and activated autophagy (enhanced LC3II/LC3I ratio). To explore changes in protein expression and intercommunication among the pathways involved in bupivacaine-induced neurotoxicity, an 8-plex iTRAQ proteomic technique and bioinformatics analysis were performed. Compared to the control group, 241 differentially expressed proteins were identified, of which, 145 were up-regulated and 96 were down-regulated. Bioinformatics analysis of the cross-talk between the significant proteins with altered expression in bupivacaine-induced neurotoxicity indicated that phosphatidyl-3-kinase (PI3K) was the most frequently targeted protein in each of the interactions. We further confirmed these results by determining the downstream targets of the identified signaling pathways (PI3K, Akt, FoxO1, Erk, and JNK). In conclusion, our study demonstrated that PI3K may play a central role in contacting and regulating the signaling pathways that contribute to bupivacaine-induced neurotoxicity.

  13. The role of the PI3K/Akt/mTOR pathway in glial scar formation following spinal cord injury.

    Science.gov (United States)

    Chen, Chun-Hong; Sung, Chun-Sung; Huang, Shi-Ying; Feng, Chien-Wei; Hung, Han-Chun; Yang, San-Nan; Chen, Nan-Fu; Tai, Ming-Hong; Wen, Zhi-Hong; Chen, Wu-Fu

    2016-04-01

    Several studies suggest that glial scars pose as physical and chemical barriers that limit neurite regeneration after spinal cord injury (SCI). Evidences suggest that the activation of the PI3K/Akt/mTOR signaling pathway is involved in glial scar formation. Therefore, inhibition of the PI3K/Akt/mTOR pathway may beneficially attenuate glial scar formation after SCI. Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) negatively regulates the PI3K/Akt/mTOR pathway. Therefore, we hypothesized that the overexpression of PTEN in the spinal cord will have beneficial effects after SCI. In the present study, we intrathecally injected a recombinant adenovirus carrying the pten gene (Ad-PTEN) to cause overexpression of PTEN in rats with contusion injured spinal cords. The results suggest overexpression of PTEN in spinal cord attenuated glial scar formation and led to improved locomotor function after SCI. Overexpression of PTEN following SCI attenuated gliosis, affected chondroitin sulfate proteoglycan expression, and improved axon regeneration into the lesion site. Furthermore, we suggest that the activation of the PI3K/Akt/mTOR pathway in astrocytes at 3 days after SCI may be involved in glial scar formation. Because delayed treatment with Ad-PTEN enhanced motor function recovery more significantly than immediate treatment with Ad-PTEN after SCI, the results suggest that the best strategy to attenuate glial scar formation could be to introduce 3 days after SCI. This study's findings thus have positive implications for patients who are unable to receive immediate medical attention after SCI.

  14. N-Carbamylglutamate Enhances Pregnancy Outcome in Rats through Activation of the PI3K/PKB/mTOR Signaling Pathway

    OpenAIRE

    Xiangfang Zeng; Zhimin Huang; Xiangbing Mao; Junjun Wang; Guoyao Wu; Shiyan Qiao

    2012-01-01

    Administration of N-carbamylglutamate (NCG), an analogue of endogenous N-acetyl-glutamate (an activator of arginine synthesis) has been shown to enhance neonatal growth by increasing circulating arginine levels. However, the effect of NCG on pregnancy remains unknown. This study examined the effects of NCG on pregnancy outcome and evaluated potential mechanisms involved. Reproductive performance, embryo implantation, and concentration of amino acids in serum and uterine flushing, were determi...

  15. The PI3K/Akt pathway is involved in early infection of some exogenous avian leukosis viruses.

    Science.gov (United States)

    Feng, Shao-zhen; Cao, Wei-sheng; Liao, Ming

    2011-07-01

    Avian leukosis virus (ALV) is an enveloped and oncogenic retrovirus. Avian leukosis caused by the members of ALV subgroups A, B and J has become one of the major problems challenging the poultry industry in China. However, the cellular factors such as signal transduction pathways involved in ALV infection are not well defined. In this study, our data demonstrated that ALV-J strain NX0101 infection in primary chicken embryo fibroblasts or DF-1 cells was correlated with the activity and phosphorylation of Akt. Akt activation was initiated at a very early stage of infection independently of NX0101 replication. The specific phosphatidylinositol 3-kinase (PI3K) inhibitors LY294002 or wortmannin could suppress Akt phosphorylation, indicating that NX0101-induced Akt phosphorylation is PI3K-dependent. ALV-A strain GD08 or ALV-B strain CD08 infection also demonstrated a similar profile of PI3K/Akt activation. Treatment of DF-1 cells with the drug 5-(N, N-hexamethylene) amiloride that inhibits the activity of chicken Na(+)/H(+) exchanger type 1 significantly reduced Akt activation induced by NX0101, but not by GD08 and CD08. Akt activation triggered by GD08 or CD08 was abolished by clathrin-mediated endocytosis inhibitor chlorpromazine. Receptor-mediated endocytosis inhibitor dansylcadaverine had a negligible effect on all ALV-induced Akt phosphorylation. Moreover, viral replication of ALV was suppressed by LY294002 in a dose-dependent manner, which was due to the inhibition of virus infection by LY294002. These data suggest that the activation of the PI3K/Akt signalling pathway by exogenous ALV infection plays an important role in viral entry, yet the precise mechanism remains under further investigation.

  16. Chlorogenic Acid Prevents Osteoporosis by Shp2/PI3K/Akt Pathway in Ovariectomized Rats

    Science.gov (United States)

    Zuo, Hui Ling; Yao, Fen Fen; Ruan, Hui Bing; Xu, Jin; Song, Wei; Zhou, Yi Cheng; Wen, Shi Yao; Dai, Jiang Hua; Zhu, Mei Lan; Luo, Jun

    2016-01-01

    Cortex Eucommiae is used worldwide in traditional medicine, various constituents of Cortex Eucommiae, such as chlorogenic acid (CGA), has been reported to exert anti-osteoporosis activity in China, but the mechanism about their contribution to the overall activity is limited. The aims of this study were to determine whether chlorogenic acid can prevent estrogen deficiency-induced osteoporosis and to analyze the mechanism of CGA bioactivity. The effect of CGA on estrogen deficiency-induced osteoporosis was performed in vivo. Sixty female Sprague-Dawley rats were divided randomly among a sham-operated group and five ovariectomy (OVX) plus treatment subgroups: saline vehicle, 17α-ethinylestradiol (E2), or CGA at 9, 27, or 45 mg/kg/d. The rats’ femoral metaphyses were evaluated by micro-computed tomography (μCT). The mechanism of CGA bioactivity was investigated in vitro. Bone mesenchymal stem cells (BMSCs) were treated with CGA, with or without phosphoinositide 3-kinase (PI3K) inhibitor LY294002. BMSCs proliferation and osteoblast differentiation were assessed with 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) and alkaline phosphatase, with or without Shp2 interfering RNA (RNAi). The results display that CGA at 27 and 45 mg/kg/day inhibited the decrease of bone mineral density (BMD) that induced by OVX in femur (p< 0.01), significantly promoted the levels of bone turnover markers, and prevented bone volume fraction (BV/TV), connectivity density (CoonD), trabecular number (Tb.N), trabecular thickness (Tb.Th) (all p< 0.01) to decrease and prevented the trabecular separation (Tb.Sp), structure model index (SMI)(both p< 0.01) to increase. CGA at 1 or 10 μM enhanced BMSC proliferation in a dose-dependent manner. CGA at 0.1 to 10 μM increased phosphorylated Akt (p-Akt) and cyclin D1. These effects were reversed by LY294002. CGA at 1 or 10 μM increased BMSC differentiation to osteoblasts (p< 0.01), Shp2 RNAi suppressed CGA-induced osteoblast

  17. Interleukin-10-induced gene expression and suppressive function are selectively modulated by the PI3K-Akt-GSK3 pathway

    Science.gov (United States)

    Antoniv, Taras T; Ivashkiv, Lionel B

    2011-01-01

    Interleukin-10 (IL-10) is an immunosuppressive cytokine that inhibits inflammatory gene expression. Phosphatidylinositol 3-kinase (PI3K) -mediated signalling regulates inflammatory responses and can induce IL-10 production, but a role for PI3K signalling in cellular responses to IL-10 is not known. In this study we investigated the involvement of the PI3K-Akt-GSK3 signalling pathway in IL-10-induced gene expression and IL-10-mediated suppression of Toll-like receptor-induced gene expression in primary human macrophages. A combination of loss and gain of function approaches using kinase inhibitors, expression of constitutively active Akt, and RNA interference in primary human macrophages showed that expression of a subset of IL-10-inducible genes was dependent on PI3K-Akt signalling. The effects of PI3K-Akt signalling on IL-10 responses were mediated at least in part by glycogen synthase kinase 3 (GSK3). In accordance with a functional role for PI3K pathways in contributing to the suppressive actions of IL-10, PI3K signalling augmented IL-10-mediated inhibition of lipopolysaccharide-induced IL-1, IL-8 and cyclo-oxygenase-2 expression. The PI3K signalling selectively modulated IL-10 responses, as it was not required for inhibition of tumour necrosis factor expression or for induction of certain IL-10-inducible genes such as SOCS3. These findings identify a new mechanism by which PI3K-mediated signalling can suppress inflammation by regulating IL-10-mediated gene induction and anti-inflammatory function. PMID:21255011

  18. Roles of PI3K/AKT/GSK3/mTOR Pathway in Cell Signaling of Mental Illnesses

    Directory of Open Access Journals (Sweden)

    Yasuko Kitagishi

    2012-01-01

    Full Text Available Several pharmacological agents acting on monoamine neurotransmission are used for the management of mental illnesses. Regulation of PI3K/AKT and GSK3 pathways may constitute an important signaling center in the subcellular integration of the synaptic neurotransmission. The pathways also modulate neuronal cell proliferation, migration, and plasticity. There are evidences to suggest that inflammation of neuron contributes to the pathology of depression. Inflammatory activation of neuron contributes to the loss of glial elements, which are consistent with pathological findings characterizing the depression. A mechanism of anti-inflammatory reactions from antidepressant medications has been found to be associated with an enhancement of heme oxygenase-1 expression. This induction in brain is also important in neuroprotection and neuroplasticity. As enzymes involved in cell survival and neuroplasticity are relevant to neurotrophic factor dysregulation, the PI3K/AKT/GSK3 may provide an important signaling for the neuroprotection in depression. In this paper, we summarize advances on the involvement of the PI3K/AKT/GSK3 pathways in cell signaling of neuronal cells in mental illnesses.

  19. Carvedilol protects bone marrow stem cells against hydrogen peroxide-induced cell death via PI3K-AKT pathway.

    Science.gov (United States)

    Chen, Meihui; Chen, Shudong; Lin, Dingkun

    2016-03-01

    Carvedilol, a nonselective β-adrenergic receptor blocker, has been reported to exert potent anti-oxidative activities. In the present study, we aimed to investigate the effects of carvedilol against hydrogen peroxide (H2O2)-induced bone marrow-derived mesenchymal stem cells (BMSCs) death, which imitate the microenvironment surrounding transplanted cells in the injured spinal cord in vitro. Carvedilol significantly reduced H2O2-induced reactive oxygen species production, apoptosis and subsequent cell death. LY294002, the PI3K inhibitor, blocked the protective effects and up-regulation of Akt phosphorylation of carvedilol. Together, our results showed that carvedilol protects H2O2-induced BMSCs cell death partly through PI3K-Akt pathway, suggesting carvedilol could be used in combination with BMSCs for the treatment of spinal cord injury by improving the cell survival and oxidative stress microenvironments.

  20. The Flavonoid Apigenin Ameliorates Cisplatin-Induced Nephrotoxicity through Reduction of p53 Activation and Promotion of PI3K/Akt Pathway in Human Renal Proximal Tubular Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Sung Min Ju

    2015-01-01

    Full Text Available Apigenin is a member of the flavone subclass of flavonoids present in fruits and vegetables. Apigenin has long been considered to have various biological activities, such as antioxidant, anti-inflammatory, and antitumorigenic properties, in various cell types. Cisplatin was known to exhibit cytotoxic effect to renal cells by inducing apoptosis through activation of p53. The present study investigated the antiapoptotic effects of apigenin on the cisplatin-treated human renal proximal tubular epithelial (HK-2 cells. HK-2 cells were pretreated with apigenin (5, 10, 20 μM for 1 h and then treated with 40 μM cisplatin for various times. Apigenin inhibited the cisplatin-induced apoptosis of HK-2 cells. Interestingly, apigenin itself exerted cytostatic activity because of its ability to induce cell cycle arrest. Apigenin inhibited caspase-3 activity and PARP cleavage in cisplatin-treated cells. Apigenin reduced cisplatin-induced phosphorylation and expression of p53, with no significant influence on production of ROS that is known to induce p53 activation. Furthermore, apigenin promoted cisplatin-induced Akt phosphorylation, suggesting that enhanced Akt activation may be involved in cytoprotection. Taken together, these results suggest that apigenin ameliorates cisplatin-induced apoptosis through reduction of p53 activation and promotion of PI3K/Akt pathway in HK-2 cells.

  1. 阻断PI3K/AKT通路通过激活FoxO1抑制猪骨骼肌卫星细胞分化%Inhibition of PI3K/AKT Pathway Suppressing Porcine Skeletal Muscle Sattelite Differentiation Through Activation of FoxO1 Transcription Factor

    Institute of Scientific and Technical Information of China (English)

    史新娥; 吴国芳; 宋子仪; 路宏朝; 贾龙; 朱嘉宇; 杨公社

    2014-01-01

    (P<0.05). Although on day 8 the cells displayed an alveolate morphology after treated with WM, they failed to show directional growth and formation of myotubes. Moreover, Western blotting results demonstrated that WM decreased the protein level of MyoD (early myogenic marker), MyoG (middle-stage marker), and MyHC (late marker) significantly.[Conclusion]Results of the study suggest that inhibition of PI3K signaling pathway by WM blocks results in FoxO1 phosphorylation, suppression of porcine skeletal muscle satellite cell differentiation, delay of the formation of myotubes, and down-regulation of myogenic differentiation marker genes, such as MyoD, MyoG, and MyHC. Take together, blockade of PI3K signaling pathway suppresses porcine skeletal muscle satellite cell differentiation through the activation of FoxO1.%[目的]在骨骼肌生长或损伤刺激下,骨骼肌卫星细胞被激活、增殖分化形成肌管,促进骨骼肌的生长发育或修复组织创伤。FoxO1负调控骨骼肌的生成,但在骨骼肌卫星细胞分化过程中的作用未见报道。因此,笔者探索FoxO1对猪骨骼肌卫星细胞分化的影响,希望为深入研究FoxO1调控骨骼肌生长发育的作用机理奠定基础。[方法]以1-3日龄健康大白猪为材料,采用单根肌纤维法分离培养猪骨骼肌卫星细胞,接种第2天、第4天和第6天在倒置显微镜下观察细胞形态并拍照。在细胞分化第8天,用免疫荧光染色方法染肌管,DAPI染核,并在荧光倒置显微镜下观察拍照。待细胞汇合至70%-80%时,将培养基换成含50 nmol·L-1渥曼青霉素(wortmannin,WM)的分化培养基,分别于细胞分化第0天、第4天和第8天收集细胞,提取总RNA和总蛋白,采用real-time qPCR和Western blotting方法检测WM对FoxO1以及骨骼肌卫星细胞分化标志基因表达的影响。[结果]猪骨骼肌卫星细胞在接种第2天开始贴壁,呈梭形。第4天细胞数量增

  2. Alteration of cellular behavior and response to PI3K pathway inhibition by culture in 3D collagen gels.

    Directory of Open Access Journals (Sweden)

    Brian Fallica

    Full Text Available Most investigations into cancer cell drug response are performed with cells cultured on flat (2D tissue culture plastic. Emerging research has shown that the presence of a three-dimensional (3D extracellular matrix (ECM is critical for normal cell behavior including migration, adhesion, signaling, proliferation and apoptosis. In this study we investigate differences between cancer cell signaling in 2D culture and a 3D ECM, employing real-time, live cell tracking to directly observe U2OS human osteosarcoma and MCF7 human breast cancer cells embedded in type 1 collagen gels. The activation of the important PI3K signaling pathway under these different growth conditions is studied, and the response to inhibition of both PI3K and mTOR with PI103 investigated. Cells grown in 3D gels show reduced proliferation and migration as well as reduced PI3K pathway activation when compared to cells grown in 2D. Our results quantitatively demonstrate that a collagen ECM can protect U2OS cells from PI103. Overall, our data suggests that 3D gels may provide a better medium for investigation of anti-cancer drugs than 2D monolayers, therefore allowing better understanding of cellular response and behavior in native like environments.

  3. Cancer Therapy Targeting the HER2-PI3K Pathway: Potential Impact on the Heart

    Directory of Open Access Journals (Sweden)

    Giannoula Lakka Klement

    2012-06-01

    Full Text Available The HER2-PI3K pathway is the one of the most mutated pathways in cancer. Several drugs targeting the major kinases of this pathway have been approved by the Food and Drug Administration and many are being tested in clinical trials for the treatment of various cancers. However, the HER2-PI3K pathway is also pivotal for maintaining the physiological function of the heart, especially in the presence of cardiac stress. Clinical studies have shown that in patients treated with doxorubicin concurrently with Trastuzumab, a monoclonal antibody that blocks the HER2 receptor, the New York Heart Association class III/IV heart failure was significantly increased compared to those who were treated with doxorubicin alone (16 vs. 3%. Studies in transgenic mice have also shown that other key kinases of this pathway, such as PI3Kα, PDK1, Akt and mTOR, are important for protecting the heart from ischemia-reperfusion and aortic stenosis induced cardiac dysfunction. Studies, however, have also shown that inhibition of PI3Kγ improve cardiac function of a failing heart. In addition, results from transgenic mouse models are not always consistent with the outcome of the pharmacological inhibition of this pathway. Here, we will review these findings and discuss how we can address the cardiac side-effects caused by inhibition of this important pathway in both cancer and cardiac biology.

  4. Effects of MAPK and PI3K Pathways on PD-L1 Expression in Melanoma

    Science.gov (United States)

    Atefi, Mohammad; Avramis, Earl; Lassen, Amanda; Wong, Deborah; Robert, Lidia; Foulad, David; Cerniglia, Michael; Titz, Bjoern; Chodon, Thinle; Graeber, Thomas G.; Comin-Anduix, Begonya; Ribas, Antoni

    2014-01-01

    Purpose PD-L1 is the main ligand for the immune inhibitory receptor PD-1. This ligand is frequently expressed by melanoma cells. In this study we investigated whether PD-L1 expression is controlled by melanoma driver mutations and modified by oncogenic signaling inhibition. Experimental Design Expression of PD-L1 was investigated in a panel of 51 melanoma cell lines containing different oncogenic mutations, including cell lines with innate and acquired resistance to BRAF inhibitors. The effects of targeted therapy drugs on expression of PD-L1 by melanoma cells were investigated. Results No association was found between the level of PD-L1 expression and mutations in BRAF, NRAS, PTEN or amplification of AKT. Resistance to vemurafenib due to the activation of alternative signaling pathways was accompanied with the induction of PD-L1 expression, while the resistance due to the reactivation of the MAPK pathway had no effect on PD-L1 expression. In melanoma cell lines the effects of BRAF, MEK and PI3K inhibitors on expression of PD-L1 were variable from reduction to induction, particularly in the presence of INFγ. In PD-L1-exposed lymphocytes, vemurafenib paradoxically restored activity of the MAPK pathway and increased the secretion of cytokines. Conclusions In melanoma cell lines, including BRAF inhibitor-resistant cells, PD-L1 expression is variably regulated by oncogenic signaling pathways. PD-L1-exposed lymphocytes decrease MAPK signaling, which is corrected by exposure to vemurafenib, providing potential benefits of combining this drug with immunotherapies. PMID:24812408

  5. DMPD: PI3K and negative regulation of TLR signaling. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 12860525 PI3K and negative regulation of TLR signaling. Fukao T, Koyasu S. Trends I...mmunol. 2003 Jul;24(7):358-63. (.png) (.svg) (.html) (.csml) Show PI3K and negative regulation of TLR signal...ing. PubmedID 12860525 Title PI3K and negative regulation of TLR signaling. Authors Fukao T, Koyasu S. Publi

  6. Wortmannin, PI3K/Akt signaling pathway inhibitor, attenuates thyroid injury associated with severe acute pancreatitis in rats.

    Science.gov (United States)

    Abliz, Ablikim; Deng, Wenhong; Sun, Rongze; Guo, Wenyi; Zhao, Liang; Wang, Weixing

    2015-01-01

    Increasing evidences suggest that PI3K/AKT pathway plays an important role in the pathogenesis of inflammatory diseases such as acute pancreatitis. However, the exact effect of PI3K/AKT on thyroid injury associated with acute pancreatitis has not been investigated. This study aimed to investigate the protective effects of wortmannin, PI3K/AKT inhibitor, on thyroid injury in a rat model of severe acute pancreatitis (SAP). Sixty male SD rats were randomly divided into four groups: sham operating group (SO), SAP group, wortmannin treatment (WOR) group and drug control (WOR-CON) group. Serum amylase (AMY), lipase (LIP) and thyroid hormone levels were evaluated. The morphological change of thyroid tissue was analyzed under the light and transmission electron microscopy. AKT, P38MAPK and NF-κB expression in the thyroid tissue was evaluated by immunohistochemical staining. Oxidative stress and inflammatory cytokines were detected. Results showed that wortmannin attenuated the following: (1) serum AMY, LIP and thyroid hormone (2) pancreatic and thyroid pathological injuries (3) thyroid MDA, (4) thyroid ultrastructural change, (5) serum TNF-α, IL-6 and IL-1β (6) AKT, MAPKP38 and NF-κB expression in thyroid tissues. These results suggested that wortmannin attenuates thyroid injury in SAP rats, presumably because of its role on prevent ROS generation and inhibits the activation of P38MAPK, NF-κB pathway. Our findings provide new therapeutic targets for thyroid injury associated with SAP.

  7. Hypoxia stimulates invasion and migration of human cervical cancer cell lines HeLa/SiHa through the Rab11 trafficking of integrin αvβ3/FAK/PI3K pathway-mediated Rac1 activation

    Indian Academy of Sciences (India)

    HAO XU; YUAN YUAN; WENQIAN WU; MIN ZHOU; QIAN JIANG; LINJUN NIU; JIAYIN JI; NIANLI LIU; LONGZHEN ZHANG; XIA WANG

    2017-09-01

    Hypoxia plays a key role in tumour cell survival, invasion, and metastasis. An increasing number of studies have attemptedto characterize the tumour response to hypoxia and to identify predictive markers of disease. Here we show that hypoxiaincreases tumour cell invasion and migration by the modulation of Rab11, an important molecule for vesicular trafficking.In our study, we found that Rab11, together with the activation of Rac1, could stimulate invasion and migration of cervicalcancer cell lines HeLa/SiHa in hypoxia. Activation of Rac1 activity by hypoxia seems to be central to carcinoma invasion.We also found that these effects could be related to the integrin αvβ3. In addition, we studied the molecular pathway for thisprocess. Our results showed that in cervical cancer cell lines HeLa/SiHa, Rac1 activation in hypoxia could stimulateinvasion and migration, and this process was mediated by integrin αvβ3-mediated FAK and PI3K phosphorylation.Furthermore, hypoxia induced a dramatic increase in αvβ3 integrin surface expression, and this increase is dependent onRab11. In conclusion, our study might provide a new mechanism for the effect of hypoxia on stimulating cervicalcarcinoma invasion.

  8. Resveratrol Increases Anti-Proliferative Activity of Bestatin Through Downregulating P-Glycoprotein Expression Via Inhibiting PI3K/Akt/mTOR Pathway in K562/ADR Cells.

    Science.gov (United States)

    Wang, Li; Wang, Changyuan; Jia, Yongming; Liu, Zhihao; Shu, Xiaohong; Liu, Kexin

    2016-05-01

    Multidrug resistance (MDR) is a major obstacle in the clinical therapy of hematological malignancies. P-glycoprotein (P-gp) overexpression results in reduction of intracellular drug concentration with a consequence that the cytotoxicity of anti-tumor drugs is decreased, which leads to MDR in K562/ADR cells. In this study, we found that resveratrol enhanced the anti-proliferative activity of bestatin in K562/ADR cells. Co-treatment with resveratrol, IC50 values of bestatin in K562/ADR cells significantly decreased and activation of caspase-3 and caspase-8 increased, which indicated that resveratrol potentiated bestatin-induced apoptosis. Resveratrol increased the intracellular concentration of bestatin through inhibiting P-gp function and downregulating P-gp expression at mRNA and protein levels, which increased anti-proliferative activity of bestatin in K562/ADR cells. Resveratrol decreased the phosphorylation of Akt and mTOR but did not affect the phosphorylations of JNK or ERK1/2. These results demonstrated that resveratrol could increase the anti-proliferative activity of bestatin through downregulating P-gp expression via suppressing the PI3K/Akt/mTOR signaling pathway.

  9. Spatholobus suberectus Column Extract Inhibits Estrogen Receptor Positive Breast Cancer via Suppressing ER MAPK PI3K/AKT Pathway

    Directory of Open Access Journals (Sweden)

    Jia-Qi Sun

    2016-01-01

    Full Text Available Although Chinese herbal compounds have long been alternatively applied for cancer treatment in China, their treatment effects have not been sufficiently investigated. The Chinese herb Spatholobus suberectus is commonly prescribed to cancer patients. HPLC analysis has shown that the main components of Spatholobus suberectus are flavonoids that can be classified as phytoestrogens, having a structure similar to estrogen. This study was designed to investigate the effects of Spatholobus suberectus column extract (SSCE on the estrogen receptor-positive (ER+ breast cancer cell line MCF-7 and its possible molecular mechanism. In our study, MTT assay was performed to evaluate cell viability. The results show that SSCE (80, 160, and 320 μg/ml significantly decreased the viability of MCF-7 cells. SSCE also triggered apoptosis, arrested the cell cycle at the G0/G1 phase, and inhibited cell migration. A dual-luciferase reporter system showed that SSCE suppressed intranuclear p-ER activity; Western blot analysis confirmed the repressed expression of phosphorylated-ER alpha (p-ERα, ERK1/2, p-ERK1/2, AKT, p-AKT, p-mTOR, PI3K, and p-PI3K, indicating that SSCE suppressed the MAPK PI3K/AKT signaling pathway. Collectively, our results suggest that SSCE causes apoptosis, an arrest in the G0/G1 phase, and a decrease in migration in ER+ MCF-7 cells via hypoactivity of the ER and suppression of the MAPK PI3K/AKT pathway.

  10. IL-10 Protects Neurites in Oxygen-Glucose-Deprived Cortical Neurons through the PI3K/Akt Pathway.

    Directory of Open Access Journals (Sweden)

    Longzai Lin

    Full Text Available IL-10, as a cytokine, has an anti-inflammatory cascade following various injuries, but it remains blurred whether IL-10 protects neurites of cortical neurons after oxygen-glucose deprivation injury. Here, we reported that IL-10, in a concentration-dependent manner, reduced neuronal apoptosis and increased neuronal survival in oxygen-glucose-deprived primary cortical neurons, producing an optimal protective effect at 20ng/ml. After staining NF-H and GAP-43, we found that IL-10 significantly protected neurites in terms of axon length and dendrite number by confocal microscopy. Furthermore, it induced the phosphorylation of AKT, suppressed the activation of caspase-3, and up-regulated the protein expression of GAP-43. In contrast, LY294002, a specific inhibitor of PI3K/AKT, reduced the level of AKT phosphorylation and GAP-43 expression, increased active caspase-3 expression and thus significantly weakened IL-10-mediated protective effect in the OGD-induced injury model. IL-10NA, the IL-10 neutralizing antibody, reduced the level of p-PI3K phosphorylation and increased the expression of active caspase-3. These findings suggest that IL-10 provides neuroprotective effects by protecting neurites through PI3K/AKT signaling pathway in oxygen-glucose-deprived primary cortical neurons.

  11. Metabolic Reprogramming by the PI3K-Akt-mTOR Pathway in Cancer.

    Science.gov (United States)

    Lien, Evan C; Lyssiotis, Costas A; Cantley, Lewis C

    In the past decade, there has been a resurgence of interest in elucidating how metabolism is altered in cancer cells and how such dependencies can be targeted for therapeutic gain. At the core of this research is the concept that metabolic pathways are reprogrammed in cancer cells to divert nutrients toward anabolic processes to facilitate enhanced growth and proliferation. Importantly, physiological cellular signaling mechanisms normally tightly regulate the ability of cells to gain access to and utilize nutrients, posing a fundamental barrier to transformation. This barrier is often overcome by aberrations in cellular signaling that drive tumor pathogenesis by enabling cancer cells to make critical cellular decisions in a cell-autonomous manner. One of the most frequently altered pathways in human cancer is the PI3K-Akt-mTOR signaling pathway. Here, we describe mechanisms by which this signaling network is responsible for controlling cellular metabolism. Through both the post-translational regulation and the induction of transcriptional programs, the PI3K-Akt-mTOR pathway coordinates the uptake and utilization of multiple nutrients, including glucose, glutamine, nucleotides, and lipids, in a manner best suited for supporting the enhanced growth and proliferation of cancer cells. These regulatory mechanisms illustrate how metabolic changes in cancer are closely intertwined with oncogenic signaling pathways that drive tumor initiation and progression.

  12. Signaling through the PI 3-K, Akt and SGK Pathway in Breast Cancer Progression

    Science.gov (United States)

    2013-12-01

    EGF (R&D Systems; Minneapolis, MN), and 100 ng/ml cholera 120 toxin (List Biological Labs; Campbell, CA); T47D and ZR-75-30 in RPMI 1640 121...Tween 20) containing 5% (w/ v ) non-fat dry milk for 30 min and then incubated with the 216 specific primary antibody diluted in blocking buffer at 4...Kinase AKT pathway in human 519 cancer. Nat. Rev. Cancer. 2002;2:489–501. 520 5. Rodon J, Dienstmann R, Serra V , Tabernero J. Development of PI3K

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

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    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.

  14. Computational drugs repositioning identifies inhibitors of oncogenic PI3K/AKT/P70S6K-dependent pathways among FDA-approved compounds

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    Carrella, Diego; Manni, Isabella; Tumaini, Barbara; Dattilo, Rosanna; Papaccio, Federica; Mutarelli, Margherita; Sirci, Francesco; Amoreo, Carla A.; Mottolese, Marcella; Iezzi, Manuela; Ciolli, Laura; Aria, Valentina; Bosotti, Roberta; Isacchi, Antonella; Loreni, Fabrizio; Bardelli, Alberto; Avvedimento, Vittorio E.; di Bernardo, Diego; Cardone, Luca

    2016-01-01

    The discovery of inhibitors for oncogenic signalling pathways remains a key focus in modern oncology, based on personalized and targeted therapeutics. Computational drug repurposing via the analysis of FDA-approved drug network is becoming a very effective approach to identify therapeutic opportunities in cancer and other human diseases. Given that gene expression signatures can be associated with specific oncogenic mutations, we tested whether a “reverse” oncogene-specific signature might assist in the computational repositioning of inhibitors of oncogenic pathways. As a proof of principle, we focused on oncogenic PI3K-dependent signalling, a molecular pathway frequently driving cancer progression as well as raising resistance to anticancer-targeted therapies. We show that implementation of “reverse” oncogenic PI3K-dependent transcriptional signatures combined with interrogation of drug networks identified inhibitors of PI3K-dependent signalling among FDA-approved compounds. This led to repositioning of Niclosamide (Niclo) and Pyrvinium Pamoate (PP), two anthelmintic drugs, as inhibitors of oncogenic PI3K-dependent signalling. Niclo inhibited phosphorylation of P70S6K, while PP inhibited phosphorylation of AKT and P70S6K, which are downstream targets of PI3K. Anthelmintics inhibited oncogenic PI3K-dependent gene expression and showed a cytostatic effect in vitro and in mouse mammary gland. Lastly, PP inhibited the growth of breast cancer cells harbouring PI3K mutations. Our data indicate that drug repositioning by network analysis of oncogene-specific transcriptional signatures is an efficient strategy for identifying oncogenic pathway inhibitors among FDA-approved compounds. We propose that PP and Niclo should be further investigated as potential therapeutics for the treatment of tumors or diseases carrying the constitutive activation of the PI3K/P70S6K signalling axis. PMID:27542212

  15. Stichopus japonicus Polysaccharide, Fucoidan, or Heparin Enhanced the SDF-1α/CXCR4 Axis and Promoted NSC Migration via Activation of the PI3K/Akt/FOXO3a Signaling Pathway.

    Science.gov (United States)

    Cui, Chao; Wang, Peng; Cui, Ningshan; Song, Shuliang; Liang, Hao; Ji, Aiguo

    2016-11-01

    Stichopus japonicus Polysaccharide (SJP) is a sulfated polysaccharide from the body wall of the sea cucumber, Stichopus japonicus. Fucoidan is a heparinoid compound that belongs to a family of sulfated polyfucose polysaccharides. Heparin is a glycosaminoglycan. SJP, fucoidan, and heparin profoundly promoted stromal cell-derived factor 1 alpha (SDF-1α)-induced neural stem cell (NSC) migration in a concentration-dependent manner. In addition, the basal migration capacity of cells was significantly promoted after incubation with SJP, fucoidan, or heparin. Interaction of SJP, fucoidan, or heparin with SDF-1α efficiently showed additive effects on the promotion of cell migration from the neurosphere. SJP, fucoidan, or heparin interaction with SDF-1α treatment could increase Nestin expression. SDF-1α modulated by SJP, fucoidan, or heparin activated the CXCR4 receptor and directed cellular migration via the activation of the PI3K/Akt/FOXO3a signaling pathway. Moreover, interaction of SJP, fucoidan, or heparin with SDF-1α effectively promoted NSC migration and induced SDF-1α and CXCR4 expressions. Results suggested that SJP, fucoidan, and heparin might be good candidates for alleviating injury-initiated signals to which NSCs respond.

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

    Science.gov (United States)

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

    2016-01-01

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

  17. Exendin-4 Promotes Beta Cell Proliferation via PI3k/Akt Signalling Pathway

    Directory of Open Access Journals (Sweden)

    Chaoxun Wang

    2015-04-01

    Full Text Available Background/Aims: Prevention of diabetes requires maintenance of a functional beta-cell mass, the postnatal growth of which depends on beta cell proliferation. Past studies have shown evidence of an effect of an incretin analogue, Exendin-4, in promoting beta cell proliferation, whereas the underlying molecular mechanisms are not completely understood. Methods: Here we studied the effects of Exendin-4 on beta cell proliferation in vitro and in vivo through analysing BrdU-incorporated beta cells. We also analysed the effects of Exendin-4 on beta cell mass in vivo, and on beta cell number in vitro. Then, we applied specific inhibitors of different signalling pathways and analysed their effects on Exendin-4-induced beta cell proliferation. Results: Exendin-4 increased beta cell proliferation in vitro and in vivo, resulting in significant increases in beta cell mass and beta cell number, respectively. Inhibition of PI3K/Akt signalling, but not inhibition of either ERK/MAPK pathway, or JNK pathway, significantly abolished the effects of Exendin-4 in promoting beta cell proliferation. Conclusion: Exendin-4 promotes beta cell proliferation via PI3k/Akt signaling pathway.

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

    Science.gov (United States)

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

    2016-01-01

    autophagy of neuroblastoma cells and consequent apoptosis through activating the PI3K/Akt/mTOR and ERS/ROS/ERK1/2 signaling pathways and suppressing cell migration. Thus, honokiol has potential for treating neuroblastomas.

  19. Static magnetic field enhances the viability and proliferation rate of adipose tissue-derived mesenchymal stem cells potentially through activation of the phosphoinositide 3-kinase/Akt (PI3K/Akt) pathway.

    Science.gov (United States)

    Marędziak, Monika; Tomaszewski, Krzysztof; Polinceusz, Paulina; Lewandowski, Daniel; Marycz, Krzysztof

    2017-01-01

    The aim of this work was to investigate the effects of 0.5T static magnetic field (sMF) on the viability and proliferation rate of human adipose-derived mesenchymal stromal stem cells (hASCs) via activation of the phosphoinositide 3-kinase/Akt (PI3K/Akt) signaling pathway. In a 7-d culture we examined cell growth kinetic and population doubling time (PDT). We also examined cell morphology and the cellular senescence markers level. Exposure to sMF enhanced the viability of these cells. However, the effect was blocked by treating the cells with LY294002, a P13K inhibitor. We compared this effect by Western Blot analysis of Akt protein expression. We also examined whether the cell response on sMF stimulation is dependent on integrin engagement and we measured integrin gene expression. Our results suggest that stimulation using sMF is a viable method to improve hASC viability. sMF is involved in mechanisms associated with controlling cell proliferative potential signaling events.

  20. Dimethyphenylpiperazinium, a nicotinic receptor agonist, downregulates inflammation in monocytes/macrophages through PI3K and PLC chronic activation.

    Science.gov (United States)

    Blanchet, Marie-Renée; Israël-Assayag, Evelyne; Daleau, Pascal; Beaulieu, Marie-Josée; Cormier, Yvon

    2006-10-01

    Activation of nicotinic acetylcholine receptors (nAChRs) on inflammatory cells induces anti-inflammatory effects. The intracellular mechanisms that regulate this effect are still poorly understood. In neuronal cells, nAChRs are associated with phosphatidylinositol 3-kinase (PI3K). This enzyme, which can activate phospholipase C (PLC), is also present in monocytes. The aim of this study was to assess the role of these proteins in the signaling pathways involved in the anti-inflammatory effect of dimethylphenylpiperazinium (DMPP), a synthetic nAChR agonist, on monocytes and macrophages. The results indicate that PI3K is associated with alpha3, -4, and -5 nAChR subunits in monocytes. The PI3K inhibitors wortmannin and LY294002 abrogated the inhibitory effect of DMPP on LPS-induced TNF release by monocytes. Treatment with DMPP for 24 and 48 h provoked a mild PLC phosphorylation, which was blocked by the nAChR antagonist mecamylamine and reversed by PI3K inhibitors. Treatment of monocytes and alveolar macrophages with DMPP reduced the inositol 1,4,5-trisphosphate (IP3)-dependent intracellular calcium mobilization induced by platelet-activating factor (PAF), an effect that was reversed by mecamylamine in alveolar macrophages. DMPP did not have any effect on PAF receptor expression. DMPP also inhibited the thapsigargin-provoked calcium release, indicating that the endoplasmic reticulum calcium stores might be depleted by treatment with the nAChR agonist. Taken together, these results suggest that PI3K and PLC activation is involved in the anti-inflammatory effect of DMPP. PLC limited, but constant activation could induce, the depletion of intracellular calcium stores, leading to the anti-inflammatory effect of DMPP.

  1. Involvement of PI3K and PKA pathways in mouse tongue epithelial differentiation.

    Science.gov (United States)

    Jung, Jae-Kwang; Jung, Hye-In; Neupane, Sanjiv; Kim, Ki-Rim; Kim, Ji-Youn; Yamamoto, Hitoshi; Cho, Sung-Won; Lee, Youngkyun; Shin, Hong-In; Sohn, Wern-Joo; Kim, Jae-Young

    2017-01-01

    In mice, tongue epithelial differentiation is mainly regulated by the interactions among various signalling molecules including Fgf signalling pathways. However, the subsequent signalling modulations for epithelial maturation, initiated by Fgf signalling, remain to be elucidated. Therefore, we employed an in vitro tongue organ cultivation system along with the applications of various pharmacological inhibitors against the intracellular signalling molecules of Fgf signalling pathways, including H89, LY294002, PD98059, and U0126. Following treatments with LY294002 and H89, inhibitors for PI3K and PKA, respectively, the decreased thickness of the tongue epithelium was observed along with the alteration in cell proliferative and apoptotic patterns. Meanwhile, cultivated tongues treated with MEK inhibitor U0126 or PD98059 showed significantly decreased cell proliferation in the tongue epithelium and the mesenchyme. Based on these results, we suggest that the tongue epithelium is differentiated into multiple epithelial cell layers via the PI3K and PKA pathways in tissue-specific manner during the epithelial-mesenchymal interactions.

  2. 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.

    Directory of Open Access Journals (Sweden)

    Wei-Ru Huang

    Full Text Available 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.

  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.

    Science.gov (United States)

    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.

  4. Probiotic-fermented purple sweet potato yogurt activates compensatory IGF‑IR/PI3K/Akt survival pathways and attenuates cardiac apoptosis in the hearts of spontaneously hypertensive rats.

    Science.gov (United States)

    Lin, Pei-Pei; Hsieh, You-Miin; Kuo, Wei-Wen; Lin, Yueh-Min; Yeh, Yu-Lan; Lin, Chien-Chung; Tsai, Fuu-Jen; Tsai, Chang-Hai; Huang, Chih-Yang; Tsai, Cheng-Chih

    2013-12-01

    Apoptosis is recognized as a predictor of adverse outcomes in subjects with cardiac diseases. The aim of this study was to explore the effects of probiotic-fermented purple sweet potato yogurt (PSPY) with high γ-aminobutyric acid (GABA) content on cardiac apoptosis in spontaneously hypertensive rat (SHR) hearts. The rats were orally adminsitered with 2 different concentrations of PSPY (10 and 100%) or captopril, 15.6 mg/kg, body weight (BW)/day. The control group was administered distilled water. DAPI and TUNEL staining were used to detect the numbers of apoptotic cells. A decrease in the number of TUNEL-positive cardiac myocytes was observed in the SHR-PSPY (10 and 100%) groups. In addition, the levels of key components of the Fas receptor- and mitochondrial-dependent apoptotic pathways were determined by western blot analysis. The results revealed that the levels of the key components of the Fas receptor- and mitochondrial-dependent apoptotic pathway were significantly decreased in the SHR-captopril, and 10 and 100% PSPY groups. Additionally, the levels of phosphorylated insulin-like growth factor‑I receptor (p-IGF‑IR) were increased in SHR hearts from the SHR-control group; however, no recovery in the levels of downstream signaling components was observed. In addition, the levels of components of the compensatory IGF-IR-dependent survival pathway (p-PI3K and p-Akt) were all highly enhanced in the left ventricles in the hearts form the SHR-10 and 100% PSPY groups. Therefore, the oral administration of PSPY may attenuate cardiomyocyte apoptosis in SHR hearts by activating IGF‑IR-dependent survival signaling pathways.

  5. Berberine protects endothelial progenitor cell from damage of TNF-α via the PI3K/AKT/eNOS signaling pathway.

    Science.gov (United States)

    Xiao, Min; Men, Li Na; Xu, Ming Guo; Wang, Guo Bing; Lv, Hai Tao; Liu, Cong

    2014-11-15

    Endothelial progenitor cells (EPCs) dysfunction is closely correlated with the coronary artery injury induced by Kawasaki disease (KD). The level of tumor necrosis factor-α (TNF-α) elevated significantly in acute phase of KD which can damage the functions of EPCs. The aim of this study was to investigate whether berberine (BBR) can protect EPCs from the inhibition caused by TNF-α via the PI3K (Phosphatidyl Inositol 3-kinase) /AKT (Serine/threonine protein kinase B) /eNOS (endothelial Nitric Oxide synthase) signaling pathway. The cell proliferative ability of EPCs was determined by MTT (methyl thiazolyl tetrazolium) assays. Nitric oxide (NO) level was determined in supernatants. The mRNA level of eNOS, PI3K and AKT were measured by Real Time-Polymerase Chain Reaction (RT-PCR), and the protein levels of eNOS, phospho-eNOS (p-eNOS), Akt, phospho-Akt (p-Akt) and PI3K were analyzed using Western-blot. The results demonstrated that TNF-α inhibits the proliferative ability of EPCs. However, BBR improves the proliferative activity of EPCs inhibited by TNF-α. Blockade of PI3K by 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (Ly294002) and blockade of eNOS by l-NAME (NG-Nitroarginine Methyl Ester) attenuates the effect of BBR. BBR can increase the level of PI3K/Akt/eNOS mRNA and the protein level of PI3K, p-Akt, eNOS and p-eNOS, which can be blocked by PI3K inhibitor (LY294002) and eNOS inhibitor (l-NAME). Therefore, we concluded that impaired EPCs proliferation could be reversed by BBR via the PI3K/AKT/eNOS signaling pathway.

  6. [Silica induced α-SMA expression in HBE cell line by targeting the PI3K/Akt pathway].

    Science.gov (United States)

    Li, Ai-ping; Hou, Zhi-guo; Fan, Jing-jing; Ji, Xiao-ming; Wang, Ting; Ni, Chun-hui

    2012-12-01

    To explore the role of the phosphatidylinositol 3 kinase/protein kinase B (PI3K/Akt) pathway in silica-induced α-SMA (α smooth muscle actin) expression in HEB (human bronchial epithelial) cell. The cultured HBE cells were divided into 5 groups: control, silica, PI3K inhibitor (Ly294002), both PI3K inhibitor (Ly294002) and silica at the same time and the inhibitor 24 h ahead of silica. The final concentrations of PI3K inhibitor and silica were 10 µmol/L and 100 µg/ml, respectively. Western blots were used to detect protein expressions of Akt, p-Akt, TGF-β and α-SMA. The location and expression of α-SMA were measured by immunofluorescence assay. HBE cell line exposed to silica can induce Akt phosphorylation, in which expressions of p-Akt were up regulated 1 times at 48 and the highest at 72 h. The expressions of TGFβ increased remarkably at 12 h and the peak at 48 h after silica exposure, while the expressions of α-SMA increased at 24 h and the highest at 72 h. However, the PI3K inhibitor (Ly294002) significantly down regulated α-SMA expression. When the cell line exposed to the PI3K inhibitor ahead of silica 24 h, the expressions of p-Akt and α-SMA were more remarkably down regulated which were decreased 1.5 times and 7.6 times respectively compare to silica exposure group. But no significant changes were found for TGFβ expressions. The immunofluorescence assay showed that silica can induce α-SMA expression, which located in cytoplasma, and PI3K inhibitor can decrease the expression. Silica induced α-SMA expression in HBE cell line is by targeting the PI3K/Akt pathway and PI3K inhibitor can repress α-SMA expression.

  7. 4-1BB signaling activates the t cell factor 1 effector/β-catenin pathway with delayed kinetics via ERK signaling and delayed PI3K/AKT activation to promote the proliferation of CD8+ T Cells.

    Directory of Open Access Journals (Sweden)

    Do Y Lee

    Full Text Available 4-1BB (CD137, an inducible costimulatory molecule, strongly enhances the proliferation and effector function of CD8(+ T cells. Since the serine/threonine kinase, glycogen synthase kinase-3 (GSK-3, is involved in a variety of signaling pathways of cellular proliferation, migration, immune responses, and apoptosis, we examined whether 4-1BB signaling activates GSK-3/β-catenin signaling and downstream transcription factors to enhance the proliferation of CD8(+ T cells. 4-1BB signaling induces rapid activation of ERK and IκB degradation, and shows delayed activation of AKT at 24 h post 4-1BB stimulation on anti-CD3 activated T cells. ERK and AKT signals were required for sustained β-catenin levels by inactivating GSK-3, which was also observed with delayed kinetics after 4-1BB stimulation. As a transcriptional partner of β-catenin, 4-1BB signaling decreased levels of FOXO1 and increased levels of stimulatory TCF1 in CD8(+ T cells at 2-3 days but not at early time points after 4-1BB engagement. The enhanced proliferation of CD8(+ T cells due to 4-1BB signaling was completely abolished by treatment with the TCF1/β-catenin inhibitor quercetin. These results show that 4-1BB signaling enhances the proliferation of activated CD8(+ T cells by activating the TCF1/β-catenin axis via the PI3K/AKT/ERK pathway. As effects of 4-1BB on AKT, FOXO1, β-catenin and GSK-3β showed delayed kinetics it is likely that an intervening molecule induced by 4-1BB and ERK signaling in activated T cells is responsible for these effects. These effects were observed on CD8(+ but not on CD4(+ T cells. Moreover, 4-1BB appeared to be unique among several TNFRs tested in inducing increase in stimulatory over inhibitory TCF-1.

  8. TDRG1 regulates chemosensitivity of seminoma TCam-2 cells to cisplatin via PI3K/Akt/mTOR signaling pathway and mitochondria-mediated apoptotic pathway.

    Science.gov (United States)

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

    2016-07-02

    We previously identified TDRG1 (testis developmental related gene 1), a novel gene with exclusive expression in testis, promoted the proliferation and progression of cultured human seminoma cells through PI3K/Akt/mTOR signaling. As increasing evidence reveal that aberrant activation of this signaling is involved in cisplatin resistance. Then, in this study, we further explored whether TDRG1 regulated the chemosensitivity of seminoma TCam-2 cells to cisplatin. Our researches showed TDRG1 could regulate the viability of TCam-2 cells following cisplatin treatment in vitro through control of both cell apoptosis and cell cycle. Mechanistically, we observed TDRG1 positively regulated the expression levels of the key elements in PI3K/Akt/mTOR pathway including p-PI3K, p-Akt and p-mTOR and also affected the translocation of nuclear p-Akt in TCam-2 cells during cisplatin treatment. Meanwhile, the levels of Bad, cytochrome c, caspase-9 ratio (activated/total), caspase-3 ratio (activated/total) and cleaved-PARP were negatively modulated by TDRG1, which meant the involvement of mitochondria-mediated apoptotic pathway. Furthermore, we found the effect of TDRG1 knockdown or TDRG1 overexpression could be reversed by IGF-1, a PI3K signaling activator, or LY294002, a inhibitor of this pathway, respectively. Similar effects of TDRG1 on cisplatin chemosensitivity and associated molecular mechanism were also confirmed in vivo by employing xenograft assays. In addition, the positive correlation between TDRG1 and p-PI3K, or p-Akt, was found in tumor tissues from seminoma patients. In conclusion, we uncover that TDRG1 regulates chemosensitivity of TCam-2 cells to cisplatin through PI3K/Akt/mTOR signaling and mitochondria-mediated apoptotic pathway both in vitro and in vivo.

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

    Science.gov (United States)

    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.

  10. Synthetic and endogenous cannabinoids protect retinal neurons from AMPA excitotoxicity in vivo, via activation of CB1 receptors: Involvement of PI3K/Akt and MEK/ERK signaling pathways.

    Science.gov (United States)

    Kokona, Despina; Thermos, Kyriaki

    2015-07-01

    Cannabinoids have been suggested to protect retinal ganglion cells in different models of toxicity, but their effects on other retinal neurons are poorly known. We investigated the neuroprotective actions of the endocannabinoid N-arachidonoyl ethanolamine (Anandamide/AEA) and the synthetic cannabinoids R1-Methanandamide (MethAEA) and HU-210, in an in vivo retinal model of AMPA excitotoxicity, and the mechanisms involved in the neuroprotection. Sprague-Dawley rats were intravitreally injected with PBS or AMPA in the absence or presence of the cannabinoid agonists. Brain nitric oxide synthase (bNOS) and choline acetyltransferase (ChAT) immunoreactivity (IR), as well as TUNEL staining, assessed the AMPA-induced retinal amacrine cell loss and the dose-dependent neuroprotection afforded by cannabinoids. The CB1 receptor selective antagonist AM251 and the PI3K/Akt inhibitor wortmannin reversed the cannabinoid-induced neuroprotection, suggesting the involvement of CB1 receptors and the PI3K/Akt pathway in cannabinoids' actions. Experiments with the CB2 agonist JWH015 and [(3)H]CP55940 radioligand binding suggested that the CB2 receptor is not involved in the neuroprotection. AEA and HU-210 induced phosphorylation of Akt but only AEA induced phosphorylation of ERK1/2 kinases, as revealed by western blot analysis. To investigate the role of caspase-3 in the AMPA-induced cell death, the caspase-3 inhibitor Z-DEVD-FMK was co-injected with AMPA. Z-DEVD-FMK had no effect on AMPA excitotoxicity. Moreover, no difference was observed in the phosphorylation of SAPK/JNK kinases between PBS- and AMPA-treated retinas. These results suggest that endogenous and synthetic cannabinoids protect retinal amacrine neurons from AMPA excitotoxicity in vivo via a mechanism involving the CB1 receptors, and the PI3K/Akt and/or MEK/ERK1/2 signaling pathways.

  11. Quercetin suppresses HeLa cells by blocking PI3K/Akt pathway.

    Science.gov (United States)

    Xiang, Tao; Fang, Yong; Wang, Shi-Xuan

    2014-10-01

    To explore the effect of quercetin on the proliferation and apoptosis of HeLa cells, HeLa cells were incubated with quercetin at different concentrations. Cell viability was evaluated by MTT assay, cell apoptosis was detected by Annexin-V/PI double labeled cytometry and DNA ladder assay. Cell cycle was flow cytometrically determined and the morphological changes of the cells were observed under a fluorescence microscope after Hoechst 33258 staining and the apoptosis-related proteins in the HeLa cells were assessed by Western blotting. The results showed that quercetin significantly inhibited the growth of HeLa cells and induced obvious apoptosis in vitro in a time- and dose-dependent manner. Moreover, quercetin induced apoptosis of HeLa cells in cell cycle-dependent manner because quercetin could induce arrest of HeLa cells at G0/G1 phase. Quercetin treatment down-regulated the expression of the PI3K and p-Akt. In addition, quercetin could down-regulate expression of bcl-2, up-regulate Bax, but exerted no effect on the overall expression of Akt. We are led to conclude that quercetin induces apoptosis via PI3k/Akt pathways, and quercetin has potential to be used as an anti-tumor agent against human cervix cancer.

  12. In Vitro Treatment of Melanoma Brain Metastasis by Simultaneously Targeting the MAPK and PI3K Signaling Pathways

    Directory of Open Access Journals (Sweden)

    Inderjit Daphu

    2014-05-01

    Full Text Available Malignant melanoma is the most lethal form of skin cancer, with a high propensity to metastasize to the brain. More than 60% of melanomas have the BRAFV600E mutation, which activates the mitogen-activated protein kinase (MAPK pathway [1]. In addition, increased PI3K (phosphoinositide 3-kinase pathway activity has been demonstrated, through the loss of activity of the tumor suppressor gene, PTEN [2]. Here, we treated two melanoma brain metastasis cell lines, H1_DL2, harboring a BRAFV600E mutation and PTEN loss, and H3, harboring WT (wild-type BRAF and PTEN loss, with the MAPK (BRAF inhibitor vemurafenib and the PI3K pathway associated mTOR inhibitor temsirolimus. Combined use of the drugs inhibited tumor cell growth and proliferation in vitro in H1_DL2 cells, compared to single drug treatment. Treatment was less effective in the H3 cells. Furthermore, a strong inhibitory effect on the viability of H1_DL2 cells, when grown as 3D multicellular spheroids, was seen. The treatment inhibited the expression of pERK1/2 and reduced the expression of pAKT and p-mTOR in H1_DL2 cells, confirming that the MAPK and PI3K pathways were inhibited after drug treatment. Microarray experiments followed by principal component analysis (PCA mapping showed distinct gene clustering after treatment, and cell cycle checkpoint regulators were affected. Global gene analysis indicated that functions related to cell survival and invasion were influenced by combined treatment. In conclusion, we demonstrate for the first time that combined therapy with vemurafenib and temsirolimus is effective on melanoma brain metastasis cells in vitro. The presented results highlight the potential of combined treatment to overcome treatment resistance that may develop after vemurafenib treatment of melanomas.

  13. Layered double hydroxide nanoparticles promote self-renewal of mouse embryonic stem cells through the PI3K signaling pathway

    Science.gov (United States)

    Wu, Youjun; Zhu, Rongrong; Zhou, Yang; Zhang, Jun; Wang, Wenrui; Sun, Xiaoyu; Wu, Xianzheng; Cheng, Liming; Zhang, Jing; Wang, Shilong

    2015-06-01

    Embryonic stem cells (ESCs) hold great potential for regenerative medicine due to their two unique characteristics: self-renewal and pluripotency. Several groups of nanoparticles have shown promising applications in directing the stem cell fate. Herein, we investigated the cellular effects of layered double hydroxide nanoparticles (LDH NPs) on mouse ESCs (mESCs) and the associated molecular mechanisms. Mg-Al-LDH NPs with an average diameter of ~100 nm were prepared by hydrothermal methods. To determine the influences of LDH NPs on mESCs, cellular cytotoxicity, self-renewal, differentiation potential, and the possible signaling pathways were explored. Evaluation of cell viability, lactate dehydrogenase release, ROS generation and apoptosis demonstrated the low cytotoxicity of LDH NPs. The alkaline phosphatase activity and the expression of pluripotency genes in mESCs were examined, which indicated that exposure to LDH NPs could support self-renewal and inhibit spontaneous differentiation of mESCs under feeder-free culture conditions. The self-renewal promotion was further proved to be independent of the leukemia inhibitory factor (LIF). Furthermore, cells treated with LDH NPs maintained the potential to differentiate into all three germ layers both in vitro and in vivo through formation of embryoid bodies and teratomas. In addition, we observed that LDH NPs initiated the activation of the PI3K/Akt pathway, while treatment with the PI3K inhibitor LY294002 could block the effects of LDH NPs on mESCs. The results confirmed that the promotion of self-renewal by LDH NPs was associated with activation of the PI3K/Akt signaling pathway. Altogether, our studies identified a new role of LDH NPs in maintaining self-renewal of mouse ES cells which could potentially be applied in stem cell research.Embryonic stem cells (ESCs) hold great potential for regenerative medicine due to their two unique characteristics: self-renewal and pluripotency. Several groups of nanoparticles

  14. Involvement of PI3K/AKT and MAPK Pathways for TNF-α Production in SiHa Cervical Mucosal Epithelial Cells Infected with Trichomonas vaginalis.

    Science.gov (United States)

    Yang, Jung-Bo; Quan, Juan-Hua; Kim, Ye-Eun; Rhee, Yun-Ee; Kang, Byung-Hyun; Choi, In-Wook; Cha, Guang-Ho; Yuk, Jae-Min; Lee, Young-Ha

    2015-08-01

    Trichomonas vaginalis; induces proinflammation in cervicovaginal mucosal epithelium. To investigate the signaling pathways in TNF-α production in cervical mucosal epithelium after T. vaginalis infection, the phosphorylation of PI3K/AKT and MAPK pathways were evaluated in T. vaginalis-infected SiHa cells in the presence and absence of specific inhibitors. T. vaginalis increased TNF-α production in SiHa cells, in a parasite burden-dependent and incubation time-dependent manner. In T. vaginalis-infected SiHa cells, AKT, ERK1/2, p38 MAPK, and JNK were phosphorylated from 1 hr after infection; however, the phosphorylation patterns were different from each other. After pretreatment with inhibitors of the PI3K/AKT and MAPK pathways, TNF-α production was significantly decreased compared to the control; however, TNF-α reduction patterns were different depending on the type of PI3K/MAPK inhibitors. TNF-α production was reduced in a dose-dependent manner by treatment with wortmannin and PD98059, whereas it was increased by SP600125. These data suggested that PI3K/AKT and MAPK signaling pathways are important in regulation of TNF-α production in cervical mucosal epithelial SiHa cells. However, activation patterns of each pathway were different from the types of PI3K/MAPK pathways.

  15. PI3K/Akt/mTOR signaling pathway and targeting therapy of skin cancer%PI3K/Akt/mTOR信号通路与皮肤肿瘤靶向治疗

    Institute of Scientific and Technical Information of China (English)

    李金超; 许爱娥

    2009-01-01

    P13K/AkdmTOR信号转导通路是促存活通路,在很多肿瘤中组成性激活.该通路激活的机制是肿瘤抑制基PTEN功能缺失、P13K扩增或突变、Akt扩增或突变.近年研究发现,该通路失常可促进肿瘤细胞的存活和生长,持续活化在皮肤肿瘤发病中起着重要的作用,已经发现抑制该通路中的信号分子可以治疗多种肿瘤,目前,针对该通路的抑制药物也在研究中,主要集中于mTOR抑制剂.%The PI3K/Akt/mTOR pathway is a prototypic survival pathway that is constitutively activated in various types of cancer. This pathway may be activated by function loss of tumor suppressor gene PTEN, amplification or mutation of PI3K and Akt genes. Recent studies have shown that the abnormality of PI3K/Akt/mTOR pathway may promote the survival and development of tumor cells, and continuous activation of this pathway is associated with the development of cutaneous tumors. It has been found that many tumors can be treated by inhibition of this pathway. Multiple inhibitors of this pathway have been developed and are being evaluated in laboratory and clinical trials, with much attention focused on mTOR inhibition.

  16. PI3K/AKT pathway mutations cause a spectrum of brain malformations from megalencephaly to focal cortical dysplasia.

    Science.gov (United States)

    Jansen, Laura A; Mirzaa, Ghayda M; Ishak, Gisele E; O'Roak, Brian J; Hiatt, Joseph B; Roden, William H; Gunter, Sonya A; Christian, Susan L; Collins, Sarah; Adams, Carissa; Rivière, Jean-Baptiste; St-Onge, Judith; Ojemann, Jeffrey G; Shendure, Jay; Hevner, Robert F; Dobyns, William B

    2015-06-01

    Malformations of cortical development containing dysplastic neuronal and glial elements, including hemimegalencephaly and focal cortical dysplasia, are common causes of intractable paediatric epilepsy. In this study we performed multiplex targeted sequencing of 10 genes in the PI3K/AKT pathway on brain tissue from 33 children who underwent surgical resection of dysplastic cortex for the treatment of intractable epilepsy. Sequencing results were correlated with clinical, imaging, pathological and immunohistological phenotypes. We identified mosaic activating mutations in PIK3CA and AKT3 in this cohort, including cancer-associated hotspot PIK3CA mutations in dysplastic megalencephaly, hemimegalencephaly, and focal cortical dysplasia type IIa. In addition, a germline PTEN mutation was identified in a male with hemimegalencephaly but no peripheral manifestations of the PTEN hamartoma tumour syndrome. A spectrum of clinical, imaging and pathological abnormalities was found in this cohort. While patients with more severe brain imaging abnormalities and systemic manifestations were more likely to have detected mutations, routine histopathological studies did not predict mutation status. In addition, elevated levels of phosphorylated S6 ribosomal protein were identified in both neurons and astrocytes of all hemimegalencephaly and focal cortical dysplasia type II specimens, regardless of the presence or absence of detected PI3K/AKT pathway mutations. In contrast, expression patterns of the T308 and S473 phosphorylated forms of AKT and in vitro AKT kinase activities discriminated between mutation-positive dysplasia cortex, mutation-negative dysplasia cortex, and non-dysplasia epilepsy cortex. Our findings identify PI3K/AKT pathway mutations as an important cause of epileptogenic brain malformations and establish megalencephaly, hemimegalencephaly, and focal cortical dysplasia as part of a single pathogenic spectrum. © The Author (2015). Published by Oxford University Press

  17. Control of fibroblast fibronectin expression and alternative splicing via the PI3K/Akt/mTOR pathway

    Energy Technology Data Exchange (ETDEWEB)

    White, Eric S., E-mail: docew@umich.edu [Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI (United States); Sagana, Rommel L.; Booth, Adam J.; Yan, Mei; Cornett, Ashley M.; Bloomheart, Christopher A.; Tsui, Jessica L.; Wilke, Carol A.; Moore, Bethany B. [Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI (United States); Ritzenthaler, Jeffrey D.; Roman, Jesse [Department of Medicine, University of Louisville School of Medicine, Louisville, KY (United States); Muro, Andres F. [International Centre for Genetic Engineering and Biotechnology, Trieste (Italy)

    2010-10-01

    Fibronectin (FN), a ubiquitous glycoprotein that plays critical roles in physiologic and pathologic conditions, undergoes alternative splicing which distinguishes plasma FN (pFN) from cellular FN (cFN). Although both pFN and cFN can be incorporated into the extracellular matrix, a distinguishing feature of cFN is the inclusion of an alternatively spliced exon termed EDA (for extra type III domain A). The molecular steps involved in EDA splicing are well-characterized, but pathways influencing EDA splicing are less clear. We have previously found an obligate role for inhibition of the tumor suppressor phosphatase and tensin homologue on chromosome 10 (PTEN), the primary regulator of the PI3K/Akt pathway, in fibroblast activation. Here we show TGF-{beta}, a potent inducer of both EDA splicing and fibroblast activation, inhibits PTEN expression and activity in mesenchymal cells, corresponding with enhanced PI3K/Akt signaling. In pten{sup -/-} fibroblasts, which resemble activated fibroblasts, inhibition of Akt attenuated FN production and decreased EDA alternative splicing. Moreover, inhibition of mammalian target of rapamycin (mTOR) in pten{sup -/-} cells also blocked FN production and EDA splicing. This effect was due to inhibition of Akt-mediated phosphorylation of the primary EDA splicing regulatory protein SF2/ASF. Importantly, FN silencing in pten{sup -/-} cells resulted in attenuated proliferation and migration. Thus, our results demonstrate that the PI3K/Akt/mTOR axis is instrumental in FN transcription and alternative splicing, which regulates cell behavior.

  18. 健脾养正消癥方通过激活PI3K/AKT信号通路减轻顺铂所致的肾毒性作用%Effect of Jianpi Yangzheng Xiaozheng Formula in Attenuating Cisplatin-induced Nephrotoxicity by Activating PI3K/AKT Signal Pathway

    Institute of Scientific and Technical Information of China (English)

    吴坚; 邹玺; 刘沈林; 陈敏; 张星星

    2015-01-01

    目的:探讨健脾养正消癥方对顺铂肾毒性的防护作用及可能机制.方法:40只BALB/C小鼠,随机分为荷瘤组,顺铂组,健脾养正消癥方组,健脾养正消癥方和顺铂(联合用药)组,每组10只,按组别ig给药5d后,将BALB/C小鼠右腋下注射H22腹水瘤,形成荷瘤小鼠模型并一次性注射顺铂20 mg· kg-造成肾损害.造模后10 d,观察小鼠肾脏指数,血肌酐(SCr),血尿素氮(BUN),肾组织病理变化;并通过TUNEL,Western blot法检测健脾养正消癥方对顺铂损伤小鼠肾组织中凋亡及PI3K/AKT信号通路相关分子蛋白表达的影响.结果:与荷瘤组比较,顺铂组小鼠肾脏系数,SCr,BUN显著升高(P<0.05),肾脏病理损伤明显,肾小管凋亡细胞增多,肾组织p-PI3K,p-AKT表达下调,Caspase-3表达上调(P<0.05);与顺铂组比较,联合用药组肾脏指数降低,SCr,BUN下降(P<0.05),肾脏病理损害减轻,肾小管凋亡细胞减少,肾组织p-PI3K,p-AKT表达上调,Caspase-3表达下调(P<0.05).结论:健脾养正消癥方能明显减轻顺铂引起的肾毒性,其作用机制与激活PI3 K/AKT信号通路,减少细胞凋亡有关.

  19. Integrin αIIb-mediated PI3K/Akt activation in platelets.

    Directory of Open Access Journals (Sweden)

    Haixia Niu

    Full Text Available Integrin αIIbβ3 mediated bidirectional signaling plays a critical role in thrombosis and haemostasis. Signaling mediated by the β3 subunit has been extensively studied, but αIIb mediated signaling has not been characterized. Previously, we reported that platelet granule secretion and TxA2 production induced by αIIb mediated outside-in signaling is negatively regulated by the β3 cytoplasmic domain residues R(724KEFAKFEEER(734. In this study, we identified part of the signaling pathway utilized by αIIb mediated outside-in signaling. Platelets from humans and gene deficient mice, and genetically modified CHO cells as well as a variety of kinase inhibitors were used for this work. We found that aggregation of TxA2 production and granule secretion by β3Δ724 human platelets initiated by αIIb mediated outside-in signaling was inhibited by the Src family kinase inhibitor PP2 and the PI3K inhibitor wortmannin, respectively, but not by the MAPK inhibitor U0126. Also, PP2 and wortmannin, and the palmitoylated β3 peptide R(724KEFAKFEEER(734, each inhibited the phosphorylation of Akt residue Ser473 and prevented TxA2 production and storage granule secretion. Similarly, Akt phosphorylation in mouse platelets stimulated by the PAR4 agonist peptide AYPGKF was αIIbβ3-dependent, and blocked by PP2, wortmannin and the palmitoylated peptide p-RKEFAKFEEER. Akt was also phosphorylated in response to mAb D3 plus Fg treatment of CHO cells in suspension expressing αIIbβ3-Δ724 or αIIbβ3E(724AERKFERKFE(734, but not in cells expressing wild type αIIbβ3. In summary, SFK(s and PI3K/Akt signaling is utilized by αIIb-mediated outside-in signaling to activate platelets even in the absence of all but 8 membrane proximal residues of the β3 cytoplasmic domain. Our results provide new insight into the signaling pathway used by αIIb-mediated outside-in signaling in platelets.

  20. Plant food anthocyanins inhibit platelet granule secretion in hypercholesterolaemia: Involving the signalling pathway of PI3K-Akt.

    Science.gov (United States)

    Song, Fenglin; Zhu, Yanna; Shi, Zhenyin; Tian, Jinju; Deng, Xiujuan; Ren, Jing; Andrews, Marc C; Ni, Heyu; Ling, Wenhua; Yang, Yan

    2014-11-01

    Controlling platelet granule secretion has been considered an effective strategy to dampen thrombosis and prevent atherosclerosis. Anthocyanins are natural plant pigments and possess a wide range of biological activities, including cardiovascular protective activity. In the present study we explored the effects and the potential mechanisms of anthocyanins on platelet granule secretion in hypercholesterolemia. In a randomised, double-blind clinical trial, 150 hypercholesterolaemic individuals were treated with purified anthocyanins (320 mg/day) or placebo for 24 weeks. Anthocyanins consumption significantly reduced plasma levels of β-thromboglobulin (β-TG), soluble P-selectin, and of Regulated on Activation Normal T cell Expressed and Secreted (RANTES) as compared with the placebo. A minor reduction in platelet factor 4 (PF4) and transforming growth factor β1 (TGF-β1) levels were also observed. In in vitro experiments, we observed that puriӿed anthocyanin mixture, as well as its two main anthocyanin components, delphinidin-3-glucoside (Dp-3-g) and cyanidin-3-glucoside (Cy-3g) directly inhibited platelet á-granule, dense granule, and lysosome secretion evaluated by P-selectin, RANTES, β-TG, PF4, TGF-β1, serotonin, ATP, and CD63 release. Further, anthocyanins inhibited platelet PI3K/Akt activation and consequently attenuated eNOS phosphorylation and cGMP production, thus interrupting MAPK activation. LY294002, a PI3K inhibitor, did not cause additional inhibitory efficacy, indicating that anthocyanin-induced effects may be involved in inhibition of the PI3K/Akt signalling pathway. These results provide evidence that by inhibiting platelet granule secretion, anthocyanins may be a potent cardioprotective agent.

  1. Somatic PI3K activity regulates transition to the spermatocyte stages in Drosophila testis

    Indian Academy of Sciences (India)

    SAMIR GUPTA; KRISHANU RAY

    2017-06-01

    Spermatogenesis, involving multiple transit amplification divisions and meiosis, occurs within an enclosure formed bytwo somatic cells. As the cohort of germline cells divide and grow, the surface areas of the somatic cells expandmaintaining a tight encapsulation throughout the developmental period. Correlation between the somatic cell growthand germline development is unclear. Here, we report standardization of a quantitative assay developed for estimatingthe somatic roles of target molecules on germline division and differentiation in Drosophila testis. Using the assay, westudied the somatic roles of phosphatidylinositol-3-kinase (PI3K). It revealed that the expression of PI3KDN is likelyto facilitate the early germline development at all stages, and an increase in the somatic PI3K activity during the earlystages delays the transition to spermatocyte stage. Together, these results suggest that somatic cell growth plays animportant role in regulating the rate of germline development.

  2. Salidroside attenuates colistin-induced neurotoxicity in RSC96 Schwann cells through PI3K/Akt pathway.

    Science.gov (United States)

    Lu, Ziyin; Jiang, Guozheng; Chen, Ying; Wang, Jian; Muhammad, Ishfaq; Zhang, Ling; Wang, Rui; Liu, Fangping; Li, Rui; Qian, Feng; Li, Jichang

    2017-06-01

    Neurotoxicity is a key dose-limiting factor for colistin therapy. This study aimed to investigate the protective effect of Salidroside on colistin-induced neurotoxicity in RSC96 Schwann cells and the underlying mechanisms. After Salidroside (12.5, 25, 50 μg/mL) treatment for 2 h, the cells were cultured with 250 μg/mL colistin for 24 h. In order to investigate the role of phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) pathway, the cells were pre-treated with LY294002 (12.5 μmol/L, a specific inhibitor of PI3K phosphorylation) for 1 h before Salidroside (50 μg/mL) treatment, then were co-cultured with colistin (250 μg/mL) for 24 h. The results showed that colistin treatment could induce apoptotic cell death which was associated with oxidative stress injury. Salidroside could reduce colistin-induced neurotoxicity, decrease the effect of colistin on the reduced expression levels of p-Akt and Bcl-2, and increased the expresion of Bax, release of Cyt c, and activation of caspase-3. However, the protective effect of Salidroside against colistin-induced apoptosis was partly abolished by LY294002. These findings suggest that Salidroside could attenuate colistin-induced neurotoxicity in RSC96 Schwann cells via the PI3K/Akt pathway. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Hematopoietic cell kinase (HCK) is a potential therapeutic target for dysplastic and leukemic cells due to integration of erythropoietin/PI3K pathway and regulation of erythropoiesis: HCK in erythropoietin/PI3K pathway.

    Science.gov (United States)

    Roversi, Fernanda Marconi; Pericole, Fernando Vieira; Machado-Neto, João Agostinho; da Silva Santos Duarte, Adriana; Longhini, Ana Leda; Corrocher, Flávia Adolfo; Palodetto, Bruna; Ferro, Karla Priscila; Rosa, Renata Giardini; Baratti, Mariana Ozello; Verjovski-Almeida, Sergio; Traina, Fabiola; Molinari, Alessio; Botta, Maurizio; Saad, Sara Teresinha Olalla

    2017-02-01

    New drug development for neoplasm treatment is nowadays based on molecular targets that participate in the disease pathogenesis and tumor phenotype. Herein, we describe a new specific pharmacological hematopoietic cell kinase (HCK) inhibitor (iHCK-37) that was able to reduce PI3K/AKT and MAPK/ERK pathways activation after erythropoietin induction in cells with high HCK expression: iHCK-37 treatment increased leukemic cells death and, very importantly, did not affect normal hematopoietic stem cells. We also present evidence that HCK, one of Src kinase family (SFK) member, regulates early-stage erythroid cell differentiation by acting as an upstream target of a frequently deregulated pathway in hematologic neoplasms, PI3K/AKT and MAPK/ERK. Notably, HCK levels were highly increased in stem cells from patients with some diseases, as Myelodysplastic Syndromes (MDS) and Acute Myeloid Leukemia (AML), that are associated with ineffective erythropoiesis These discoveries support the exploration of the new pharmacological iHCK-37 in future preclinical and clinical studies.

  4. Gomisin N Inhibits Melanogenesis through Regulating the PI3K/Akt and MAPK/ERK Signaling Pathways in Melanocytes.

    Science.gov (United States)

    Chae, Jae Kyoung; Subedi, Lalita; Jeong, Minsun; Park, Yong Un; Kim, Chul Young; Kim, Hakwon; Kim, Sun Yeou

    2017-02-22

    Gomisin N, one of the lignan compounds found in Schisandra chinensis has been shown to possess anti-oxidative, anti-tumorigenic, and anti-inflammatory activities in various studies. Here we report, for the first time, the anti-melenogenic efficacy of Gomisin N in mammalian cells as well as in zebrafish embryos. Gomisin N significantly reduced the melanin content without cellular toxicity. Although it was not capable of modulating the catalytic activity of mushroom tyrosinase in vitro, Gomisin N downregulated the expression levels of key proteins that function in melanogenesis. Gomisin N downregulated melanocortin 1 receptor (MC1R), adenylyl cyclase 2, microphthalmia-associated transcription factor (MITF), tyrosinase, tyrosinase-related protein-1 (TRP-1), and tyrosinase-related protein-2 (TRP-2). In addition, Gomisin N-treated Melan-A cells exhibited increased p-Akt and p-ERK levels, which implies that the activation of the PI3K/Akt and MAPK/ERK pathways may function to inhibit melanogenesis. We also validated that Gomisin N reduced melanin production by repressing the expression of MITF, tyrosinase, TRP-1, and TRP-2 in mouse and human cells as well as in developing zebrafish embryos. Collectively, we conclude that Gomisin N inhibits melanin synthesis by repressing the expression of MITF and melanogenic enzymes, probably through modulating the PI3K/Akt and MAPK/ERK pathways.

  5. Gomisin N Inhibits Melanogenesis through Regulating the PI3K/Akt and MAPK/ERK Signaling Pathways in Melanocytes

    Science.gov (United States)

    Chae, Jae Kyoung; Subedi, Lalita; Jeong, Minsun; Park, Yong Un; Kim, Chul Young; Kim, Hakwon; Kim, Sun Yeou

    2017-01-01

    Gomisin N, one of the lignan compounds found in Schisandra chinensis has been shown to possess anti-oxidative, anti-tumorigenic, and anti-inflammatory activities in various studies. Here we report, for the first time, the anti-melenogenic efficacy of Gomisin N in mammalian cells as well as in zebrafish embryos. Gomisin N significantly reduced the melanin content without cellular toxicity. Although it was not capable of modulating the catalytic activity of mushroom tyrosinase in vitro, Gomisin N downregulated the expression levels of key proteins that function in melanogenesis. Gomisin N downregulated melanocortin 1 receptor (MC1R), adenylyl cyclase 2, microphthalmia-associated transcription factor (MITF), tyrosinase, tyrosinase-related protein-1 (TRP-1), and tyrosinase-related protein-2 (TRP-2). In addition, Gomisin N-treated Melan-A cells exhibited increased p-Akt and p-ERK levels, which implies that the activation of the PI3K/Akt and MAPK/ERK pathways may function to inhibit melanogenesis. We also validated that Gomisin N reduced melanin production by repressing the expression of MITF, tyrosinase, TRP-1, and TRP-2 in mouse and human cells as well as in developing zebrafish embryos. Collectively, we conclude that Gomisin N inhibits melanin synthesis by repressing the expression of MITF and melanogenic enzymes, probably through modulating the PI3K/Akt and MAPK/ERK pathways. PMID:28241436

  6. Gomisin N Inhibits Melanogenesis through Regulating the PI3K/Akt and MAPK/ERK Signaling Pathways in Melanocytes

    Directory of Open Access Journals (Sweden)

    Jae Kyoung Chae

    2017-02-01

    Full Text Available Gomisin N, one of the lignan compounds found in Schisandra chinensis has been shown to possess anti-oxidative, anti-tumorigenic, and anti-inflammatory activities in various studies. Here we report, for the first time, the anti-melenogenic efficacy of Gomisin N in mammalian cells as well as in zebrafish embryos. Gomisin N significantly reduced the melanin content without cellular toxicity. Although it was not capable of modulating the catalytic activity of mushroom tyrosinase in vitro, Gomisin N downregulated the expression levels of key proteins that function in melanogenesis. Gomisin N downregulated melanocortin 1 receptor (MC1R, adenylyl cyclase 2, microphthalmia-associated transcription factor (MITF, tyrosinase, tyrosinase-related protein-1 (TRP-1, and tyrosinase-related protein-2 (TRP-2. In addition, Gomisin N-treated Melan-A cells exhibited increased p-Akt and p-ERK levels, which implies that the activation of the PI3K/Akt and MAPK/ERK pathways may function to inhibit melanogenesis. We also validated that Gomisin N reduced melanin production by repressing the expression of MITF, tyrosinase, TRP-1, and TRP-2 in mouse and human cells as well as in developing zebrafish embryos. Collectively, we conclude that Gomisin N inhibits melanin synthesis by repressing the expression of MITF and melanogenic enzymes, probably through modulating the PI3K/Akt and MAPK/ERK pathways.

  7. miR-218 inhibits the invasion and migration of colon cancer cells by targeting the PI3K/Akt/mTOR signaling pathway.

    Science.gov (United States)

    Zhang, Xiangliang; Shi, Huijuan; Tang, Hongsheng; Fang, Zhiyuan; Wang, Jiping; Cui, Shuzhong

    2015-05-01

    Colon cancer is one of the most common and lethal malignancies worldwide. Despite major advances in the treatment of colon cancer, the prognosis remains very poor. Thus, novel and effective therapies for colon cancer are urgently needed. In the present study, the expression status of miR-218 and the role of the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) pathway were investigated in colon cancer samples. Firstly, we observed that miR-218 expression was significantly reduced, while PI3K/Akt/mTOR pathway activity was enhanced. The overexpression of miR-218 suppressed the proliferation, migration and invasion of LoVo colon cancer cells, whereas the inhibition of miR-218 promoted these processes. Furthermore, the PI3K/Akt/mTOR signaling pathway was identified as a direct target of miR-218. The upregulation of miR-218 inhibited the activation of the PI3K/Akt/mTOR signaling pathway, as well as the expression of matrix metalloproteinase (MMP)9. The downregulation of miR-218 activated the PI3K/Akt/mTOR signaling pathway and promoted MMP9 expression. Taken together, our results demonstrate that miR-218 suppresses the proliferation, migration and invasion of LoVo colon cancer cells by targeting the PI3K/Akt/mTOR signaling pathway and MMP9. Our data indicate that miR-218 is a potential target in the treatment of colon cancer.

  8. Gas6 Delays Senescence in Vascular Smooth Muscle Cells through the PI3K/ Akt/FoxO Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Cheng-wei Jin

    2015-02-01

    Full Text Available Background/Aims: Growth arrest-specific protein 6 (Gas6 is a cytokine that can be synthesized by a variety of cell types and secreted into the extracellular matrix. Previous studies have confirmed that Gas6 is involved in certain pathophysiological processes of the cardiovascular system through binding to its receptor, Axl. In the present study, we investigated the role of Gas6 in cellular senescence and explored the mechanisms underlying its activity. Methods: We used vascular smooth muscle cells (VSMCs to create two cellular senescence models, one for replicative senescence (RS and one for induced senescence (IS, to test the hypothesis that Gas6 delays senescence. Results: Gas6-treated cells appear relatively younger compared with non-Gas6-treated cells. In particular, Gas6-treated cells displayed decreased staining for SA-β-Gal, fewer G1 phase cells, and decreased levels of p16INK4a and p21Cip1 expression; conversely, Gas6-treated cells displayed more S phase cells and significantly increased proliferation indexes. Furthermore, in both the IS and RS models with Gas6 treatment, the levels of PI3K, p-Akt, and p-FoxO3a decreased following Axl inhibition by R428; similarly, the levels of p-Akt and p-FoxO3a also decreased following PI3K inhibition by LY294002. Conclusion: Gas6/Axl signaling is essential for delaying the cellular senescence process regulated by the PI3K/Akt/FoxO signaling pathway.

  9. Nonsteroidal anti-inflammatory drugs modulate cellular glycosaminoglycan synthesis by affecting EGFR and PI3K signaling pathways

    Science.gov (United States)

    Mozolewski, Paweł; Moskot, Marta; Jakóbkiewicz-Banecka, Joanna; Węgrzyn, Grzegorz; Bocheńska, Katarzyna; Banecki, Bogdan; Gabig-Cimińska, Magdalena

    2017-01-01

    In this report, selected non-steroidal anti-inflammatory drugs (NSAIDs), indomethacin and nimesulide, and analgesics acetaminophen, alone, as well as in combination with isoflavone genistein as potential glycosaminoglycan (GAG) metabolism modulators were considered for the treatment of mucopolysaccharidoses (MPSs) with neurological symptoms due to the effective blood-brain barrier (BBB) penetration properties of these compounds. We found that indomethacin and nimesulide, but not acetaminophen, inhibited GAG synthesis in fibroblasts significantly, while the most pronounced impairment of glycosaminoglycan production was observed after exposure to the mixture of nimesulide and genistein. Phosphorylation of the EGF receptor (EGFR) was inhibited even more effective in the presence of indomethacin and nimesulide than in the presence of genistein. When examined the activity of phosphatidylinositol-3-kinase (PI3K) production, we observed its most significant decrease in the case of fibroblast exposition to nimesulide, and afterwards to indomethacin and genistein mix, rather than indomethacin used alone. Some effects on expression of individual GAG metabolism-related and lysosomal function genes, and significant activity modulation of a number of genes involved in intracellular signal transduction pathways and metabolism of DNA and proteins were detected. This study documents that NSAIDs, and their mixtures with genistein modulate cellular glycosaminoglycan synthesis by affecting EGFR and PI3K signaling pathways. PMID:28240227

  10. Quercetin postconditioning attenuates myocardial ischemia/reperfusion injury in rats through the PI3K/Akt pathway

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    Y. Wang

    2013-09-01

    Full Text Available Quercetin (Que, a plant-derived flavonoid, has multiple benefical actions on the cardiovascular system. The current study investigated whether Que postconditioning has any protective effects on myocardial ischemia/reperfusion (I/R injury in vivo and its potential cardioprotective mechanisms. Male Sprague-Dawley rats were randomly allocated to 5 groups (20 animals/group: sham, I/R, Que postconditioning, Que+LY294002 [a phosphatidylinositol 3-kinase (PI3K/Akt signaling pathway inhibitor], and LY294002+I/R. I/R was produced by 30-min coronary occlusion followed by 2-h reperfusion. At the end of reperfusion, myocardial infarct size and biochemical changes were compared. Apoptosis was evaluated by both TUNEL staining and measurement of activated caspase-3 immunoreactivity. The phosphorylation of Akt and protein expression of Bcl-2 and Bax were determined by Western blotting. Que postconditioning significantly reduced infarct size and serum levels of creatine kinase and lactate dehydrogenase compared with the I/R group (all P<0.05. Apoptotic cardiomyocytes and caspase-3 immunoreactivity were also suppressed in the Que postconditioning group compared with the I/R group (both P<0.05. Akt phosphorylation and Bcl-2 expression increased after Que postconditioning, but Bax expression decreased. These effects were inhibited by LY294002. The data indicate that Que postconditioning can induce cardioprotection by activating the PI3K/Akt signaling pathway and modulating the expression of Bcl-2 and Bax proteins.

  11. Quercetin postconditioning attenuates myocardial ischemia/reperfusion injury in rats through the PI3K/Akt pathway

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y.; Zhang, Z.Z.; Wu, Y.; Ke, J.J.; He, X.H.; Wang, Y.L. [Department of Anesthesiology, Zhongnan Hospital, Wuhan University, Wuhan (China)

    2013-09-24

    Quercetin (Que), a plant-derived flavonoid, has multiple benefical actions on the cardiovascular system. The current study investigated whether Que postconditioning has any protective effects on myocardial ischemia/reperfusion (I/R) injury in vivo and its potential cardioprotective mechanisms. Male Sprague-Dawley rats were randomly allocated to 5 groups (20 animals/group): sham, I/R, Que postconditioning, Que+LY294002 [a phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway inhibitor], and LY294002+I/R. I/R was produced by 30-min coronary occlusion followed by 2-h reperfusion. At the end of reperfusion, myocardial infarct size and biochemical changes were compared. Apoptosis was evaluated by both TUNEL staining and measurement of activated caspase-3 immunoreactivity. The phosphorylation of Akt and protein expression of Bcl-2 and Bax were determined by Western blotting. Que postconditioning significantly reduced infarct size and serum levels of creatine kinase and lactate dehydrogenase compared with the I/R group (all P<0.05). Apoptotic cardiomyocytes and caspase-3 immunoreactivity were also suppressed in the Que postconditioning group compared with the I/R group (both P<0.05). Akt phosphorylation and Bcl-2 expression increased after Que postconditioning, but Bax expression decreased. These effects were inhibited by LY294002. The data indicate that Que postconditioning can induce cardioprotection by activating the PI3K/Akt signaling pathway and modulating the expression of Bcl-2 and Bax proteins.

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

    Science.gov (United States)

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

    2015-10-01

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

  13. Id-1 promotes osteosarcoma cell growth and inhibits cell apoptosis via PI3K/AKT signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Liang; Liao, Qi; Tang, Qiang [Department of Orthopaedic Surgery, The Second Affiliated Hospital of Nanchang University, Nanchang 300006 (China); Deng, Huan [Department of Pathology, The Fourth Affiliated Hospital of Nanchang University, Nanchang 330006 (China); Chen, Lu, E-mail: chenlu0578@163.com [Department of Orthopaedic Surgery, The Second Affiliated Hospital of Nanchang University, Nanchang 300006 (China)

    2016-02-12

    Accumulating evidence reveals that Id-1 is upregulated and functions as a potential tumor promoter in several human cancer types. However, the role of Id-1 in osteosarcoma (OS) is unknown. In present study, we found that Id-1 expression was elevated in OS tissues than adjacent normal bone tissues. More importantly, we demonstrated that overexpression of Id-1 is significantly correlated with tumor progression and poor survival in OS patients. Furthermore, increased expression of Id-1 was observed in OS cell lines and ectopic expression of Id-1 significantly enhanced in vitro cell proliferation and promoted in vivo tumor growth, whereas knockdown of Id-1 suppressed OS cells growth. Moreover, our experimental data revealed that Id-1 promotes cell proliferation by facilitating cell cycle progression and inhibits cell apoptosis. Mechanistically, the effects of Id-1 in OS cells is at least partly through activation of PI3K/Akt signaling pathway. Therefore, we identified a tumorigenic role of Id-1 in OS and suggested a potential therapeutic target for OS patients. - Highlights: • Id-1 expression is positively correlated in OS patients with poor prognosis. • Overexpression of Id-1 promotes OS cell growth in vitro and in vivo. • Id-1induces cell cycle progression and inhibits cell apoptosis. • PI3K/Akt signaling pathway contributed to the oncogenic effects of Id-1 in OS cells.

  14. PI3K/mTOR-dependent signaling pathway as a possible regulator of processing bodies’ assembly

    Directory of Open Access Journals (Sweden)

    Filonenko V. V.

    2011-10-01

    Full Text Available Aim. To study the role of PI3K/mTOR signaling pathway in regulation of processing body (PB assembly. Methods. During this study we employed cell imaging technique and Western blot analysis. Results. It was shown that treatment of cells with the specific inhibitors of PI3K/mTOR pathway leads to changes of PBs’ number and size within cells as well as proteasomal degradation of their scaffold protein RCD-8. Conclusions. We speculate that mTOR/PI3K pathway may regulate in part the dynamic of PB formation in the cell by affecting the stability of RCD-8 protein and therefore controle mRNA metabolism

  15. Regulation of the PI3K pathway through a p85a monomer-homodimer equilibrium

    KAUST Repository

    Aljedani, Safia

    2017-01-08

    The phosphatidylinositol-3-kinase a (PI3Ka) is heterodimeric enzyme that is composed of p85a regulatory subunit and a p110a catalytic subunit. PI3Ka plays a key role in cell survival, growth and differentation. Owing to its role as a key regulator, the PI3Ka pathway is the most frequently mutated pathway in human cancers, and is targeted by many viruses to insure their survival and successful reproduction. Previous studies have shown that the equilibrium of p85 monomers and dimers regulates the PI3K pathway, suggesting that interrupting this equilibrium could lead to disease development. Moreover, studies suggest that the p85a monomers and dimers have opposing effects on PI3Ka signaling as only the p85a dimers bind to the PTEN phosphatase, whereas p85a monomers bind to the catalytic p110 subunit. However, the mechanism for dimerisation is controversial, and it is unknown why PTEN or p110a bind only dimer or monomer. Therefore, we combine molecular biology, biophsical, computational and structural methods to investigate the suprosingly complex p85 dimerisation mechanism and its control by ligands. Results may inspire novel theraputic approaches.

  16. Icariin Prevents Amyloid Beta-Induced Apoptosis via the PI3K/Akt Pathway in PC-12 Cells

    Directory of Open Access Journals (Sweden)

    Dongdong Zhang

    2015-01-01

    Full Text Available Icariin is a prenylated flavonol glycoside derived from the Chinese herb Epimedium sagittatum that exerts a variety of pharmacological activities and shows promise in the treatment and prevention of Alzheimer’s disease. In this study, we investigated the neuroprotective effects of icariin against amyloid beta protein fragment 25–35 (Aβ25–35 induced neurotoxicity in cultured rat pheochromocytoma PC12 cells and explored potential underlying mechanisms. Our results showed that icariin dose-dependently increased cell viability and decreased Aβ25–35-induced apoptosis, as assessed by MTT assay and Annexin V/propidium iodide staining, respectively. Results of western blot analysis revealed that the selective phosphatidylinositol 3-kinase (PI3K inhibitor LY294002 suppressed icariin-induced Akt phosphorylation, suggesting that the protective effects of icariin are associated with activation of the PI3K/Akt signaling pathway. LY294002 also blocked the icariin-induced downregulation of proapoptotic factors Bax and caspase-3 and upregulation of antiapoptotic factor Bcl-2 in Aβ25–35-treated PC12 cells. These findings provide further evidence for the clinical efficacy of icariin in the treatment of Alzheimer’s disease.

  17. Long noncoding RNA HULC promotes cell proliferation by regulating PI3K/AKT signaling pathway in chronic myeloid leukemia.

    Science.gov (United States)

    Lu, Yinghao; Li, Yan; Chai, Xiao; Kang, Qian; Zhao, Peng; Xiong, Jie; Wang, Jishi

    2017-04-05

    Aberrant expression of long noncoding RNA (lncRNA) HULC is associated with various human cancers. However, the role of HULC in chronic myeloid leukemia (CML) is unknown. In this study, we found that HULC was remarkably overexpressed in both leukemia cell lines and primary hematopoietic cells derived from CML patients. The increase in HULC expression was positively correlated with clinical stages in CML. Moreover, the knockdown of HULC significantly inhibited CML cell proliferation and induced apoptosis by repressing c-Myc and Bcl-2. Furthermore, inhibition of HULC enhanced imatinib-induced apoptosis of CML cells. Further experiments demonstrated that HULC silencing markedly suppressed the phosphorylation of PI3K and AKT, indicating that enhancement of imatinib-induced apoptosis by HULC inhibition is related with the reduction of c-Myc expression and inhibition of PI3K/Akt pathway activity. Furthermore, HULC could modulate c-Myc and Bcl-2 by miR-200a as an endogenous sponge. Taken together, these results reveal that HULC promotes oncogenesis in CML and suggest a potential strategy for the CML treatment.

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

    Directory of Open Access Journals (Sweden)

    Yu-Yo Sun

    Full Text Available 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.

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

    Science.gov (United States)

    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.

  20. Inhibition of PI3K/BMX Cell Survival Pathway Sensitizes to BH3 Mimetics in SCLC.

    Science.gov (United States)

    Potter, Danielle S; Galvin, Melanie; Brown, Stewart; Lallo, Alice; Hodgkinson, Cassandra L; Blackhall, Fiona; Morrow, Christopher J; Dive, Caroline

    2016-06-01

    Most small cell lung cancer (SCLC) patients are initially responsive to cytotoxic chemotherapy, but almost all undergo fatal relapse with progressive disease, highlighting an urgent need for improved therapies and better patient outcomes in this disease. The proapoptotic BH3 mimetic ABT-737 that targets BCL-2 family proteins demonstrated good single-agent efficacy in preclinical SCLC models. However, so far clinical trials of the BH3 mimetic Navitoclax have been disappointing. We previously demonstrated that inhibition of a PI3K/BMX cell survival signaling pathway sensitized colorectal cancer cells to ABT-737. Here, we show that SCLC cell lines, which express high levels of BMX, become sensitized to ABT-737 upon inhibition of PI3K in vitro, and this is dependent on inhibition of the PI3K-BMX-AKT/mTOR signaling pathway. Consistent with these cell line data, when combined with Navitoclax, PI3K inhibition suppressed tumor growth in both an established SCLC xenograft model and in a newly established circulating tumor cell-derived explant (CDX) model generated from a blood sample obtained at presentation from a chemorefractory SCLC patient. These data show for the first time that a PI3K/BMX signaling pathway plays a role in SCLC cell survival and that a BH3 mimetic plus PI3K inhibition causes prolonged tumor regression in a chemorefractory SCLC patient-derived model in vivo These data add to a body of evidence that this combination should move toward the clinic. Mol Cancer Ther; 15(6); 1248-60. ©2016 AACR.

  1. Dual Inhibition of PI3K/AKT and MEK/ERK Pathways Induces Synergistic Antitumor Effects in Diffuse Intrinsic Pontine Glioma Cells

    Directory of Open Access Journals (Sweden)

    Y. Linda Wu

    2017-04-01

    Full Text Available Diffuse intrinsic pontine glioma (DIPG is a devastating disease with an extremely poor prognosis. Recent studies have shown that platelet-derived growth factor receptor (PDGFR and its downstream effector pathway, PI3K/AKT/mTOR, are frequently amplified in DIPG, and potential therapies targeting this pathway have emerged. However, the addition of targeted single agents has not been found to improve clinical outcomes in DIPG, and targeting this pathway alone has produced insufficient clinical responses in multiple malignancies investigated, including lung, endometrial, and bladder cancers. Acquired resistance also seems inevitable. Activation of the Ras/Raf/MEK/ERK pathway, which shares many nodes of cross talk with the PI3K/AKT pathway, has been implicated in the development of resistance. In the present study, perifosine, a PI3K/AKT pathway inhibitor, and trametinib, a MEK inhibitor, were combined, and their therapeutic efficacy on DIPG cells was assessed. Growth delay assays were performed with each drug individually or in combination. Here, we show that dual inhibition of PI3K/AKT and MEK/ERK pathways synergistically reduced cell viability. We also reveal that trametinib induced AKT phosphorylation in DIPG cells that could not be effectively attenuated by the addition of perifosine, likely due to the activation of other compensatory mechanisms. The synergistic reduction in cell viability was through the pronounced induction of apoptosis, with some effect from cell cycle arrest. We conclude that the concurrent inhibition of the PI3K/AKT and MEK/ERK pathways may be a potential therapeutic strategy for DIPG.

  2. Anger Emotional Stress Influences VEGF/VEGFR2 and Its Induced PI3K/AKT/mTOR Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Peng Sun

    2016-01-01

    Full Text Available Objective. We discuss the influence of anger emotional stress upon VEGF/VEGFR2 and its induced PI3K/AKT/mTOR signal pathway. Methods. We created a rat model of induced anger (anger-out and anger-in emotional response using social isolation and resident-intruder paradigms and assessed changes in hippocampus’ VEGF content, neuroplasticity, and the PI3K/AKT/mTOR signaling pathway. Results. The resident-intruder method successfully generated anger-out and anger-in models that differed significantly in composite aggression score, aggression incubation, open field behavior, sucrose preference, and weight gain. Anger emotional stress decreased synaptic connections and VEGFR2 expression. Anger emotional stress led to abnormal expression of VEGF/VEGFR2 mRNA and protein and disorderly expression of key factors in the PI3K/AKT/mTOR signal pathway. Fluoxetine administration ameliorated behavioral abnormalities and damage to hippocampal neurons caused by anger emotional stress, as well as abnormal expression of some proteins in VEGF/VEGFR2 and its induced PI3K/AKT/mTOR signal pathway. Conclusion. This research provides a detailed classification of anger emotion and verifies its influence upon VEGF and the VEGF-induced signaling pathway, thus providing circumstantial evidence of mechanisms by which anger emotion damages neurogenesis. As VEGFR2 can promote neurogenesis and vasculogenesis in the hippocampus and frontal lobe, these results suggest that anger emotional stress can result in decreased neurogenesis.

  3. Frequent alterations of the PI3K/AKT/mTOR pathways in hereditary nonpolyposis colorectal cancer

    DEFF Research Database (Denmark)

    Jönsson, Mats; Ekstrand, Anna Isinger; Jönsson, Mats;

    2010-01-01

    The phosphatidylinositol 3-kinases-AKT-mammalian target of rapamycin pathway (PI3K/AKT/mTOR) is central in colorectal tumors. Data on its role in hereditary cancers are, however, scarce and we therefore characterized mutations in PIK3CA and KRAS, and expression of PIK3CA, phosphorylated AKT...

  4. Exposure to bisphenol A at physiological concentrations observed in Chinese children promotes primordial follicle growth through the PI3K/Akt pathway in an ovarian culture system.

    Science.gov (United States)

    Zhao, Qian; Ma, Yan; Sun, Ning-Xia; Ye, Chen; Zhang, Qing; Sun, Shu-Han; Xu, Chen; Wang, Fang; Li, Wen

    2014-12-01

    The worldwide increase in the use of bisphenol A (BPA) has resulted in increased human exposure, which could affect human reproductive function. Few studies have investigated the effect of BPA exposure on the primordial follicle pool. In this study, we employed a neonatal ovarian culture system comprising organ obtained from female C57BL/6 pups on postnatal day 4 to assess the effect of BPA on the primordial follicle pool. Ovaries were cultured with BPA (0.1 μM, physiological concentration found in children's blood, and 1 μM, 10 μM) or vehicle for 10 days. Our study revealed that the primary follicle number increased during the early time points (⩽5 days), and we observed a reduction in the primordial follicle pool at a later time point (day 10). This reduction at day 10 was due to increased follicle activation and reduced follicle atresia, as determined by immunohistochemistry for Ki-67 and active caspase-3. Then we examined the phosphatidylinositol-3-kinase (PI3K)/Akt pathway, which is known to be important for early follicle growth. BPA exposure induced the upregulation of the PI3K/Akt pathway, which was reversed by concomitant treatment with PI3K inhibitor. Our results reveal a novel mechanism for BPA-induced primordial follicle activation that involves the PI3K/Akt pathway. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Inhibition of PI3K/Akt pathway impairs G2/M transition of cell cycle in late developing progenitors of the avian embryo retina.

    Directory of Open Access Journals (Sweden)

    Isis Moraes Ornelas

    Full Text Available PI3K/Akt is an important pathway implicated in the proliferation and survival of cells in the CNS. Here we investigated the participation of the PI3K/Akt signal pathway in cell cycle of developing retinal progenitors. Immunofluorescence assays performed in cultures of chick embryo retinal cells and intact tissues revealed the presence of phosphorylated Akt and 4E-BP1 in cells with typical mitotic profiles. Blockade of PI3K activity with the chemical inhibitor LY 294002 (LY in retinal explants blocked the progression of proliferating cells through G2/M transition, indicated by an expressive increase in the number of cells labeled for phosphorylated histone H3 in the ventricular margin of the retina. No significant level of cell death could be detected at this region. Retinal explants treated with LY for 24 h also showed a significant decrease in the expression of phospho-Akt, phospho-GSK-3 and the hyperphosphorylated form of 4E-BP1. Although no change in the expression of cyclin B1 was detected, a significant decrease in CDK1 expression was noticed after 24 h of LY treatment both in retinal explants and monolayer cultures. Our results suggest that PI3K/Akt is an active pathway during proliferation of retinal progenitors and its activity appears to be required for proper CDK1 expression levels and mitosis progression of these cells.

  6. Inhibition of PI3K/Akt pathway impairs G2/M transition of cell cycle in late developing progenitors of the avian embryo retina.

    Science.gov (United States)

    Ornelas, Isis Moraes; Silva, Thayane Martins; Fragel-Madeira, Lucianne; Ventura, Ana Lucia Marques

    2013-01-01

    PI3K/Akt is an important pathway implicated in the proliferation and survival of cells in the CNS. Here we investigated the participation of the PI3K/Akt signal pathway in cell cycle of developing retinal progenitors. Immunofluorescence assays performed in cultures of chick embryo retinal cells and intact tissues revealed the presence of phosphorylated Akt and 4E-BP1 in cells with typical mitotic profiles. Blockade of PI3K activity with the chemical inhibitor LY 294002 (LY) in retinal explants blocked the progression of proliferating cells through G2/M transition, indicated by an expressive increase in the number of cells labeled for phosphorylated histone H3 in the ventricular margin of the retina. No significant level of cell death could be detected at this region. Retinal explants treated with LY for 24 h also showed a significant decrease in the expression of phospho-Akt, phospho-GSK-3 and the hyperphosphorylated form of 4E-BP1. Although no change in the expression of cyclin B1 was detected, a significant decrease in CDK1 expression was noticed after 24 h of LY treatment both in retinal explants and monolayer cultures. Our results suggest that PI3K/Akt is an active pathway during proliferation of retinal progenitors and its activity appears to be required for proper CDK1 expression levels and mitosis progression of these cells.

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

    Science.gov (United States)

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

    2014-01-31

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

  8. Leptin regulates proliferation and apoptosis of colorectal carcinoma through PI3K/Akt/mTOR signalling pathway

    Indian Academy of Sciences (India)

    Di Wang; Jian Chen; Hui Chen; Zhi Duan; Qimei Xu; Meiyan Wei; Lianghua Wang; Meizuo Zhong

    2012-03-01

    Epidemiological studies have indicated that obesity is associated with colorectal cancer. The obesity hormone leptin is considered as a key mediator for cancer development and progression. The present study aims to investigate regulatory effects of leptin on colorectal carcinoma. The expression of leptin and its receptor Ob-R was examined by immunohistochemistry in 108 Chinese patients with colorectal carcinoma. The results showed that leptin/Ob-R expression was significantly associated with T stage, TNM stage, lymph node metastasis, distant metastasis, differentiation and expression of p-mTOR, p-70S6 kinase, and p-Akt. Furthermore, the effects of leptin on proliferation and apoptosis of HCT-116 colon carcinoma cells were determined. The results showed that leptin could stimulate the proliferation and inhibit the apoptosis of HCT-116 colon cells through the PI3K/Akt/mTOR pathway. Ly294002 (a PI3K inhibitor) and rapamycin (an mTOR inhibitor) could prevent the regulatory effects of leptin on the proliferation and apoptosis of HCT-116 cells via abrogating leptin-mediated PI3K/Akt/mTOR pathway. All these results indicated that leptin could regulate proliferation and apoptosis of colorectal carcinoma through the PI3K/Akt/mTOR signalling pathway.

  9. Pioglitazone inhibition of lipopolysaccharide-induced nitric oxide synthase is associated with altered activity of p38 MAP kinase and PI3K/Akt

    Directory of Open Access Journals (Sweden)

    Hunter Randy

    2008-01-01

    pioglitazone on the LPS-induced NO increase. Conclusion We demonstrate that pioglitazone protects dopaminergic neurons against LPS insult at least via inhibiting iNOS expression and NO generation, which is potentially mediated via inhibition of p38 MAPK activity. In addition, the PI3K pathway actively participates in the negative regulation of LPS-induced NO production. Our findings suggest that PPAR-γ activation may involve differential regulation of p38 MAPK and of the PI3K/Akt pathway in the regulation of the inflammatory process.

  10. PI3K/Akt Pathway Contributes to Neurovascular Unit Protection of Xiao-Xu-Ming Decoction against Focal Cerebral Ischemia and Reperfusion Injury in Rats

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    Rui Lan

    2013-01-01

    Full Text Available In the present study, we used a focal cerebral ischemia and reperfusion rat model to investigate the protective effects of Xiao-Xu-Ming decoction (XXMD on neurovascular unit and to examine the role of PI3K (phosphatidylinositol 3-kinase/Akt pathway in this protection. The cerebral ischemia was induced by 90 min of middle cerebral artery occlusion. Cerebral infarct area was measured by tetrazolium staining, and neurological function was observed at 24 h after reperfusion. DNA fragmentation assay, combined with immunofluorescence, was performed to evaluate apoptosis of neuron, astrocyte, and vascular endothelial cell which constitute neurovascular unit. The expression levels of proteins involved in PI3K/Akt pathway were detected by Western blot. The results showed that XXMD improved neurological function, decreased cerebral infarct area and neuronal damage, and attenuated cellular apoptosis in neurovascular unit, while these effects were abolished by inhibition of PI3K/Akt with LY294002. We also found that XXMD upregulated p-PDKl, p-Akt, and p-GSK3β expression levels, which were partly reversed by LY294002. In addition, the increases of p-PTEN and p-c-Raf expression levels on which LY294002 had no effect were also observed in response to XXMD treatment. The data indicated the protective effects of XXMD on neurovascular unit partly through the activation of PI3K/Akt pathway.

  11. Upregulation of heme oxygenase-1 via PI3K/Akt and Nrf-2 signaling pathways mediates the anti-inflammatory activity of Schisandrin in Porphyromonas gingivalis LPS-stimulated macrophages.

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    Park, Sun Young; Park, Da Jung; Kim, Young Hun; Kim, Younghee; Kim, Sun Gun; Shon, Kwang Jae; Choi, Young-Whan; Lee, Sang-Joon

    2011-09-30

    The lipopolysaccharide (LPS) of Porphyromonas gingivalis is thought to induce periodontitis. In this study, we isolated Schisandrin from the dried fruits of Schisandra chinensis and examined the anti-inflammatory effect of Schisandrin in macrophages stimulated with LPS from P. gingivalis. First, Schisandrin inhibited LPS-induced pro-inflammatory cytokines, including TNF-α, IL-1β, and IL-6. And Schisandrin suppressed the nuclear translocation and activity of NF-κB and phosphorylation of IκBα in LPS-stimulated RAW 264.7 cells. Next, the presence of a selective inhibitor of HO-1 (SnPP) and a siRNA specific for HO-1 inhibited Schisandrin-mediated anti-inflammatory activity. Furthermore, Schisandrin induced HO-1 expression of RAW 264.7 cells through Nrf-2, PI3K/Akt, and ERK activation. Therefore, these results suggest that the anti-inflammatory effects of Schisandrin on P. gingivalis LPS-stimulated RAW 264.7 cells may be due to a reduction of NF-κB activity and induction of the expression of HO-1, leading to TNF-α, IL-1β, and IL-6 down-regulation.

  12. Postconditioning with sevoflurane protects against focal cerebral ischemia and reperfusion injury via PI3K/Akt pathway.

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    Wang, Jun-Kuan; Yu, Li-Na; Zhang, Feng-Jiang; Yang, Mei-Juan; Yu, Jing; Yan, Min; Chen, Gao

    2010-10-21

    Emerging evidence has demonstrated that postconditioning with sevoflurane provided neuroprotection. In this study, we investigated the neuroprotective effect of different concentrations of sevoflurane in rats with middle cerebral artery occlusion (MCAO). Furthermore, we tested the hypothesis that the neuroprotective effect of postconditioning with sevoflurane is associated with inhibition of apoptosis and mediated by activation of the phosphoinositide-3-kinase/Akt (PI3K/Akt) pathway. Adult male Sprague-Dawley rats were subjected to MCAO for 90 min and then treated with sevoflurane at the beginning of reperfusion. The infarct volume, neurological deficit scores and brain edema were evaluated at 24 hours. Spatial learning and memory was examined by Morris water maze. Apoptosis and apoptosis-related proteins were studied by TUNEL, immunohistochemistry and western blot. The neuroprotective effect and the amount of p-Akt after sevoflurane administration with or without wortmannin were analyzed. Postconditioning with sevoflurane 1.0 minimum alveolar concentration (MAC) and 1.5 MAC significantly decreased neurological deficit scores, infarct volume and brain edema and markedly improved spatial learning and memory. Postconditioning also reduced apoptotic cells, upregulated Bcl-2 and downregulated P53 and Bax. Wortmannin abolished the neuroprotective effect and prevented the increasing of p-Akt. Our data suggest postconditioning with sevoflurane (1.0 MAC and 1.5 MAC) not only reduced infarct volume but also improved learning and memory. Our study further showed that this neuroprotective effect may be partly due to the activation of PI3K/Akt pathway and inhibiting neuronal apoptosis.

  13. Morphine Suppresses T helper Lymphocyte Differentiation to Th1 Type Through PI3K/AKT Pathway.

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    Mao, Mao; Qian, Yanning; Sun, Jie

    2016-04-01

    To investigate the effect of morphine on T helper lymphocyte differentiation and PI3K/AKT pathway mechanism, CD4+ lymphocytes were treated by phorbol-myristate-acetate (25 ng/ml) (PMA) plus ionomycin (1 μg/ml) in the presence of various concentrations of morphine (25, 50, 100, 200 ng/ml) for 4 h. Th1 and Th2 subsets, supernatant cytokines, and PI3K, AKT, and protein kinase C-theta (PKC-θ) levels were detected. The Th1 cell percentage, Th1-derived cytokines, and ratio of Th1/Th2 decreased in the presence of morphine in a concentration-dependent manner. However, Th2 cell percentage kept stable after morphine treatment. The phosphorylation of PI3K and AKT decreased, but the phosphorylation of PKC-θ did not change in the presence of morphine. The decreased percentage of Th1 cells and ratio of Th1/Th2 was recovered by naloxone concentration-dependently. Morphine can inhibit the differentiation of Th1 lymphocytes and decrease the ratio of Th1/Th2 via the pathway of PI3K/AKT. The effect can be inhibited by naloxone.

  14. Cbl-b and PI3K/Akt pathway are differently involved in oxygen-glucose deprivation preconditioning in PC12 cells

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wei; YU Huan; ZOU Wei; WANG Yan-fu; LIANG Xiao-feng; ZHANG Bo; KONG Jing-jing

    2013-01-01

    Background Transient sublethal ischemia is known as ischemic preconditioning,which enables cells and tissues to survive subsequent prolonged lethal ischemic injury.Ischemic preconditioning exerts neuroprotection through phosphatidylinositol 3-kinase (PI3K)/Akt pathway.Cbl-b belongs to the Casitas B-lineage lymphoma (Cbl) family,and it can regulate the cell signal transduction.The roles of ubiquitin ligase Cbl-b and PI3K/Akt pathway and the relationship between them in oxygen-glucose deprivation preconditioning (OGDPC) in PC12 cells were investigated in the present study.Methods Oxygen and glucose deprivation (OGD) model in PC12 cells was used in the present study.The 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay,nuclear staining with Hoechst 33258,and Western blotting were applied to explore the roles of Cbl-b and PI3K/Akt pathway and the relationship between them in OGDPC in PC12 cells.Results Cell viability was significantly changed by OGD and OGDPC.OGD significantly decreased cell viability compared with the control group (P <0.05),and preconditioning could rescue this damage was demonstrated by the increase of cell viability (P <0.05).The expression of Cbl-b was significantly increased after OGD treatment.However,the activation of Akt and GSK3β was greatly inhibited.Preconditioning could inhibit the increase of Cbl-b caused by OGD and increase the activation of Akt and GSK3β.LY294002,a specific inhibitor of PI3K,could effectively inhibit the increase of Akt and GSK3β after preconditioning treatment.It partly inhibited the decrease of Cbl-b expression after preconditioning treatment.Conclusion Ubiquitin ligase Cbl-b and PI3K/Akt pathway are differently involved in OGDPC in PC12 cells.

  15. Anti-inflammatory effect of honokiol is mediated by PI3K/Akt pathway suppression1

    Institute of Scientific and Technical Information of China (English)

    Byung Hun KIM; Jae Youl CHO

    2008-01-01

    Aim: In this study, we investigated the regulatory effects of honokiol on various inflammatory events mediated by monocytes/macrophages (U937/RAW264.7 cells)and lymphocytes (splenic lymphocytes and CTLL-2 cells) and their putative ac-tion mechanism. Methods: In order to investigate the regulatory effects, various cell lines and primary cells (U937, RAW264.7, CTLL-2 cells, and splenic lymphocytes) were employed and various inflammatory events, such as the pro-duction of inflammatory mediators, cell adhesion, cell proliferation, and the early signaling cascade, were chosen. Results: Honokiol strongly inhibited various inflammatory responses, such as: (ⅰ) the upregulation of nitric oxide (NO), pros-taglandin.E2 and TNF-α production and costimulatory molecule CD80 induced by lipopolysaccharide (LPS); (ⅱ) the functional activation of β1-integrin (CD29) as-sessed by U937 cell-cell and cell-fibronectin adhesions; (ⅲ) the enhancement of lymphocytes and CD8+CTLL-2 cell proliferation stimulated by LPS, phytohemaglutinin A (PHA), and concanavalin A or interleukin (IL)-2; and (ⅳ) the transcriptional upregulation of inducible NO synthase, TNF-α, cyclooxygenase-2, IL-12, and monocyte chemoattractant protein (MCP)-1. These anti-inflammatory effects of honokiol seem to be mediated by interrupting the early activated intra-cellular signaling molecule phosphoinositide 3-kinase (PI3K)/Akt, but not Src, the extracellular signal-regulated kinase, and p38, according to pharmacological, biochemical, and functional analyses. Conclusion: These results suggest that honokiol may act as a potent anti-inflammatory agent with multipotential activities due to an inhibitory effect on the PI3K/Akt pathway.

  16. Salidroside protects against hydrogen peroxide-induced injury in cardiac H9c2 cells via PI3K-Akt dependent pathway.

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    Zhu, Ye; Shi, Ya-Ping; Wu, Dan; Ji, Ya-Jing; Wang, Xue; Chen, Hua-Li; Wu, Si-Si; Huang, De-Jia; Jiang, Wei

    2011-10-01

    Oxidative stress induces serious tissue injury in cardiovascular diseases. Salidroside, with its strong antioxidative and cytoprotective actions, is of particular interest in the development of antioxidative therapies for oxidative injury in cardiac diseases. We examined the pharmacological effects of salidroside on H9c2 rat cardiomyoblast cells under conditions of oxidative stress induced by hydrogen peroxide (H2O2) challenge. Salidroside attenuated H2O2-impaired cell viability in a concentration-dependent manner, and effectively inhibited cellular malondialdehyde production, lethal sarcolemmal disruption, cell necrosis, and apoptosis induced by H2O2 insult. Salidroside significantly augmented Akt phosphorylation at Serine 473 in the absence or presence of H2O2 stimulation; wortmannin, a specific inhibitor of PI3K, abrogated salidroside protection. Salidroside increased the intracellular mRNA expression and activities of catalase and Mn-superoxide dismutases in a PI3K-dependent manner. Our results indicated that salidroside protected cardiomyocytes against oxidative injury through activating the PI3K/Akt pathway and increasing the expression and activities of endogenous PI3K dependent antioxidant enzymes.

  17. Computer-Aided Targeting of the PI3K/Akt/mTOR Pathway: Toxicity Reduction and Therapeutic Opportunities

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    Tan Li

    2014-10-01

    Full Text Available The PI3K/Akt/mTOR pathway plays an essential role in a wide range of biological functions, including metabolism, macromolecular synthesis, cell growth, proliferation and survival. Its versatility, however, makes it a conspicuous target of many pathogens; and the consequential deregulations of this pathway often lead to complications, such as tumorigenesis, type 2 diabetes and cardiovascular diseases. Molecular targeted therapy, aimed at modulating the deregulated pathway, holds great promise for controlling these diseases, though side effects may be inevitable, given the ubiquity of the pathway in cell functions. Here, we review a variety of factors found to modulate the PI3K/Akt/mTOR pathway, including gene mutations, certain metabolites, inflammatory factors, chemical toxicants, drugs found to rectify the pathway, as well as viruses that hijack the pathway for their own synthetic purposes. Furthermore, this evidence of PI3K/Akt/mTOR pathway alteration and related pathogenesis has inspired the exploration of computer-aided targeting of this pathway to optimize therapeutic strategies. Herein, we discuss several possible options, using computer-aided targeting, to reduce the toxicity of molecularly-targeted therapy, including mathematical modeling, to reveal system-level control mechanisms and to confer a low-dosage combination therapy, the potential of PP2A as a therapeutic target, the formulation of parameters to identify patients who would most benefit from specific targeted therapies and molecular dynamics simulations and docking studies to discover drugs that are isoform specific or mutation selective so as to avoid undesired broad inhibitions. We hope this review will stimulate novel ideas for pharmaceutical discovery and deepen our understanding of curability and toxicity by targeting the PI3K/Akt/mTOR pathway.

  18. The role of sodium hydrosulfide in attenuating the aging process via PI3K/AKT and CaMKKβ/AMPK pathways

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    Xubo Chen

    2017-08-01

    Full Text Available Age-related dysfunction of the central auditory system, known as central presbycusis, is characterized by defects in speech perception and sound localization. It is important to determine the pathogenesis of central presbycusis in order to explore a feasible and effective intervention method. Recent work has provided fascinating insight into the beneficial function of H2S on oxidative stress and stress-related disease. In this study, we investigated the pathogenesis of central presbycusis and tried to explore the mechanism of H2S action on different aspects of aging by utilizing a mimetic aging rat and senescent cellular model. Our results indicate that NaHS decreased oxidative stress and apoptosis levels in an aging model via CaMKKβ and PI3K/AKT signaling pathways. Moreover, we found that NaHS restored the decreased activity of antioxidants such as GSH, SOD and CAT in the aging model in vivo and in vitro by regulating CaMKKβ and PI3K/AKT. Mitochondria function was preserved by NaHS, as indicated by the following: DNA POLG and OGG-1, the base excision repair enzymes in mitochondrial, were upregulated; OXPHOS activity was downregulated; mitochondrial membrane potential was restored; ATP production was increased; and mtDNA damage, indicated by the common deletion (CD, declined. These effects were also achieved by activating CaMKKβ/AMPK and PI3K/AKT signaling pathways. Lastly, protein homeostasis, indicated by HSP90 alpha, was strengthened by NaHS via CaMKKβ and PI3K/AKT. Our findings demonstrate that the ability to resist oxidative stress and mitochondria function are both decreased as aging developed; however, NaHS, a novel free radical scavenger and mitochondrial protective agent, precludes the process of oxidative damage by activating CaMKKβ and PI3K/AKT. This study might provide a therapeutic target for aging and age-related disease.

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

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    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.

  20. Correlation between PTEN Expression and PI3K/Akt Signal Pathway in Endometrial Carcinoma

    Institute of Scientific and Technical Information of China (English)

    Qinglei GAO; Fei YE; Xi XIA; Hui XING; Yunping LU; Jianfeng ZHOU; Ding MA

    2009-01-01

    In order to investigate the role of the PTEN expression in carcinogenesis and develop-ment of endometrial carcinoma and clarify whether and how PTEN and PI3K/Akt pathway relate to endometrial carcinoma,the expression of PTEN and phospho-Akt was detected by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) methods and Western-blot from 24 cases of endomctrial carcinoma,10 cases of endometrial atypical hyperplasia,10 cases of endometrial hy-perplasia,and 10 cases of normal endometrium.SP immunohistochemical methods were used to measure levels of PTEN protein expression in following 5 study groups:31 cases of endometrium in proliferative phase,30 cases of endometrium in secretory phase,71 cases of endometrial hyperplasia,25 cases of atypical hyperplasia and 73 cases of endometrial carcinoma.Immunostaining score of PTEN was 3.39±0.15 in proliferative phase,1.90±0.21 in secretory phase,3.34~0.29 in endometrial hyperplasia,0.624±0.11 in atypical hyperplasia,and 0.74±0.19 in endometrial carcinoma,respectively.PTEN mRNA relative value in normal endometrium,endometrial hyperplasia,endometrial atypical hyperplasia,and endometrial carcinoma was 2.45±0.51,2.32±0.32,0.46±0.11,and 0.35±0.13 respec-tively.The expression levels of PTEN mRNA and protein in patients with endometrial carcinoma and atypical hyperplasia were significantly lower than in those of proliferative phase and with endo-metrial hyperplasia.The level of PTEN expression in patients with endometrial carcinoma was sig-nificantly related to tissue type (P0.05).Western blot analysis revealed that Phospho-Akt level in PTEN negative cases was significantly higher,and there was a negative correlation between PTEN and phospho-Akt (r=- 0.8973,P<0.0001).It was suggested that loss of PTEN expression was an early event in endometrial tumorigenesis.The phosphorylation of Akt induced by the loss of PTEN took part in the tumorigenesis and development of endometrial carcinoma.

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

    Science.gov (United States)

    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 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 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.

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

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    Yong-sen Jia

    2015-01-01

    Full Text Available 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.

  3. Contribution of Natural Inhibitors to the Understanding of the PI3K/PDK1/PKB Pathway in the Insulin-mediated Intracellular Signaling Cascade

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    Jae Youl Cho

    2008-11-01

    Full Text Available The critical initial steps in insulin action include phosphorylation of adapter proteins and activation of phosphatidylinositol 3-kinase (PI3K. One of important components in this process is a protein called Akt/protein kinase B (PKB. The work of numerous different researchers indicates a role of PKB in regulating insulin-stimulated glucose uptake. The crucial role of lipid second messengers in PKB activation has been dissected through the use of the PI3K-specific inhibitors wortmannin and LY294002. Receptor-activated PI3K synthesizes the lipid second messenger PtdIns[3,4,5]-trisphosphate, leading to the recruitment of PKB to the membrane. Membrane attachment of PKB is mediated by its pleckstrin homology domain binding to PtdIns[3,4,5]-trisphosphate or PtdIns[3,4]-bisphosphate with high affinity. Activation of PKB alpha is then achieved at the plasma membrane by phosphorylation of Thr308 in the activation-loop of the kinase domain and Ser473 in the carboxy-terminal regulatory region, respectively. 3-Phosphoinositide-dependent protein kinase-1 (PDK1 is responsible for T308 phosphorylation. The usage of specific inhibitors and natural compound has significantly contributed to investigate the molecular mechanism of PI3K/PDK1/PKB signaling pathway, leading to the putative therapeutics benefits of patients. This review focuses on the contribution of natural inhibitor or compound in our understanding of the mechanism by which insulin induces, especially in PI3K/ PDK1/PKB signaling.

  4. Saposin C promotes survival and prevents apoptosis via PI3K/Akt-dependent pathway in prostate cancer cells

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    Lee Tae-Jin

    2004-11-01

    Full Text Available Abstract Background In addition to androgens, growth factors are also implicated in the development and neoplastic growth of the prostate gland. Prosaposin is a potent neurotrophic molecule. Homozygous inactivation of prosaposin in mice has led to the development of a number of abnormalities in the male reproductive system, including atrophy of the prostate gland and inactivation of mitogen-activated protein kinase (MAPK and Akt in prostate epithelial cells. We have recently reported that prosaposin is expressed at a higher level by androgen-independent (AI prostate cancer cells as compared to androgen-sensitive prostate cancer cells or normal prostate epithelial and stromal cells. In addition, we have demonstrated that a synthetic peptide (prosaptide TX14A, derived from the trophic sequence of the saposin C domain of prosaposin, stimulated cell proliferation, migration and invasion and activated the MAPK signaling pathway in prostate cancer cells. The biological significances of saposin C and prosaposin in prostate cancer are not known. Results Here, we report that saposin C, in a cell type-specific and dose-dependent manner, acts as a survival factor, activates the Akt-signaling pathway, down-modulates caspase-3, -7, and -9 expression and/or activity, and decreases the cleaved nuclear substrate of caspase-3 in prostate cancer cells under serum-starvation stress. In addition, prosaptide TX14A, saposin C, or prosaposin decreased the growth-inhibitory effect, caspase-3/7 activity, and apoptotic cell death induced by etoposide. We also discovered that saposin C activates the p42/44 MAP kinase pathway in a pertussis toxin-sensitive and phosphatidylinositol 3-kinase (PI3K /Akt-dependent manner in prostate cancer cells. Our data also show that the anti-apoptotic activity of saposin C is at least partially mediated via PI3K/Akt signaling pathway. Conclusion We postulate that as a mitogenic, survival, and anti-apoptotic factor for prostate cancer cells

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    Olivia Hatton

    Full Text Available 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. Hyperbaric oxygen protects mandibular condylar chondrocytes from interleukin-1β-induced apoptosis via the PI3K/AKT signaling pathway

    Science.gov (United States)

    Chen, Hang; Wu, Gaoyi; Sun, Qi; Dong, Yabing; Zhao, Huaqiang

    2016-01-01

    Objectives: Mandibular condylar chondrocyte apoptosis is mainly responsible for the development and progression of temporomandibular joint osteoarthritis (TMJ-OA). Interleukin-1β (IL-1β) generally serves an agent that induces chondrocyte apoptosis. Hyperbaric oxygen (HBO) treatment increases proteoglycan synthesis in vivo. We explore the protective effect of HBO on IL-1β-induced mandibular condylar chondrocyte apoptosis in rats and the potential molecular mechanisms. Methods: Chondrocytes were isolated from the TMJ of 3-4-week old Sprague-Dawley rats. The Cell Counting Kit-8 (CCK-8) assay was used to determine cell viability. The phosphorylated phosphoinositide-3 kinase (p-PI3K), phosphorylated AKT (p-Akt), type II collagen (COL2), and aggrecan (AGG) content was detected by immunofluorescence, immunocytochemistry and western blotting. The expression of Pi3k, Akt, Col2 and Agg mRNA was measured using real-time quantitative polymerase chain reaction (RT-qPCR). Results: HBO inhibited the cytotoxicity and apoptosis induced by IL-1β (10 ng/mL) in the mandibular condylar chondrocytes. HBO also decreased the IL-1β activity that decreased p-PI3K and p-AKT levels, and increased COL2 and AGG expression, with the net effect of suppressing extracellular matrix degradation. Conclusions: These data suggest that HBO may protect mandibular condylar chondrocytes against IL-1β-induced apoptosis via the PI3K/AKT signaling pathway, and that it may promote the expression of mandibular condylar chondrocyte extracellular matrix through the PI3K/AKT signaling pathway. PMID:27904712

  8. Hydrostatic Compress Force Enhances the Viability and Decreases the Apoptosis of Condylar Chondrocytes through Integrin-FAK-ERK/PI3K Pathway

    Science.gov (United States)

    Ma, Dandan; Kou, Xiaoxing; Jin, Jing; Xu, Taotao; Wu, Mengjie; Deng, Liquan; Fu, Lusi; Liu, Yi; Wu, Gang; Lu, Haiping

    2016-01-01

    Reduced mechanical stimuli in many pathological cases, such as hemimastication and limited masticatory movements, can significantly affect the metabolic activity of mandibular condylar chondrocytes and the growth of mandibles. However, the molecular mechanisms for these phenomena remain unclear. In this study, we hypothesized that integrin-focal adhesion kinase (FAK)-ERK (extracellular signal–regulated kinase)/PI3K (phosphatidylinositol-3-kinase) signaling pathway mediated the cellular response of condylar chondrocytes to mechanical loading. Primary condylar chondrocytes were exposed to hydrostatic compressive forces (HCFs) of different magnitudes (0, 50, 100, 150, 200, and 250 kPa) for 2 h. We measured the viability, morphology, and apoptosis of the chondrocytes with different treatments as well as the gene, protein expression, and phosphorylation of mechanosensitivity-related molecules, such as integrin α2, integrin α5, integrin β1, FAK, ERK, and PI3K. HCFs could significantly increase the viability and surface area of condylar chondrocytes and decrease their apoptosis in a dose-dependent manner. HCF of 250 kPa resulted in a 1.51 ± 0.02-fold increase of cell viability and reduced the ratio of apoptotic cells from 18.10% ± 0.56% to 7.30% ± 1.43%. HCFs could significantly enhance the mRNA and protein expression of integrin α2, integrin α5, and integrin β1 in a dose-dependent manner, but not ERK1, ERK2, or PI3K. Instead, HCF could significantly increase phosphorylation levels of FAK, ERK1/2, and PI3K in a dose-dependent manner. Cilengitide, the potent integrin inhibitor, could dose-dependently block such effects of HCFs. HCFs enhances the viability and decreases the apoptosis of condylar chondrocytes through the integrin-FAK-ERK/PI3K pathway. PMID:27827993

  9. Novel agents and associated toxicities of inhibitors of the pi3k/Akt/mtor pathway for the treatment of breast cancer

    OpenAIRE

    Chia, S.; Gandhi, S.; Joy, A.A.; Edwards, S.; Gorr, M.; Hopkins, S; Kondejewski, J.; Ayoub, J.P.; Califaretti, N.; Rayson, D.; Dent, S.F.

    2015-01-01

    The pi3k/Akt/mtor (phosphatidylinositol 3 kinase/ Akt/mammalian target of rapamycin) signalling pathway is an established driver of oncogenic activity in human malignancies. Therapeutic targeting of this pathway holds significant promise as a treatment strategy. Everolimus, an mtor inhibitor, is the first of this class of agents approved for the treatment of hormone receptor–positive, human epidermal growth factor receptor 2–negative advanced breast cancer. Everolimus has been associated with...

  10. The phosphatidylinositol 3-kinases (PI3K) inhibitor GS-1101 synergistically potentiates histone deacetylase inhibitor-induced proliferation inhibition and apoptosis through the inactivation of PI3K and extracellular signal-regulated kinase pathways.

    Science.gov (United States)

    Bodo, Juraj; Zhao, Xiaoxian; Sharma, Arishya; Hill, Brian T; Portell, Craig A; Lannutti, Brian J; Almasan, Alexandru; Hsi, Eric D

    2013-10-01

    Previously, we showed that inhibition of the protein kinase C β (PKCβ)/AKT pathway augments engagement of the histone deacetylase inhibitor (HDI)-induced apoptosis in lymphoma cells. In the present study, we investigated the cytotoxicity and mechanisms of cell death induced by the delta isoform-specific phosphatidylinositide 3-kinase (PI3K) inhibitor, GS-1101, in combination with the HDI, panobinostat (LBH589) and suberoylanilide hydroxamic acid (SAHA). Lymphoma cell lines, primary non-Hodgkin Lymphoma (NHL) and chronic lymphocytic leukaemia (CLL) cells were simultaneously treated with the HDI, LBH589 and GS-1101. An interaction of the LBH589/GS-1101 combination was formally examined by using various concentrations of LBH589 and GS-1101. Combined treatment resulted in a synergistic inhibition of proliferation and showed synergistic effect on apoptotic induction in all tested cell lines and primary NHL and CLL cells. This study indicates that interference with PI3K signalling dramatically increases HDI-mediated apoptosis in malignant haematopoietic cells, possibly through both AKT-dependent or AKT- independent mechanisms. Moreover, the increase in HDI-related apoptosis observed in PI3K inhibitor-treated cells appears to be related to the disruption of the extracellular signal-regulated kinase (ERK) signalling pathway. This study provides a strong rational for testing the combination of PI3K inhibitors and HDI in the clinic.

  11. PI3K-Akt-mTOR and MAPK signaling pathways in polycystic ovarian syndrome, uterine leiomyomas and endometriosis: an update.

    Science.gov (United States)

    Makker, Annu; Goel, Madhu Mati; Das, Vinita; Agarwal, Anjoo

    2012-03-01

    PI3K-Akt-mTOR and MAP kinase are two important cell signaling pathways that are activated by steroid hormones and growth factors leading to cellular events including gene expression, cell proliferation and survival. These pathways are considered as an attractive target for the development of novel anticancer molecules, and selective inhibitors specifically targeting different components of these cascades have been developed. This review summarizes the current available knowledge on the PI3K-Akt-mTOR and MAPK pathways and their targeting in estrogen-dependent benign gynecological disorders viz. polycystic ovarian syndrome, uterine leiomyomas and endometriosis, which are a significant cause of high morbidity in women of reproductive age group. Increasing knowledge about the role of the two growth regulatory pathways in the pathogenesis of these disorders may give the opportunity to use specific signal transduction inhibitors for management of these patients in future.

  12. Protective Effect of Tempol on Acute Kidney Injury Through PI3K/Akt/Nrf2 Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Gensheng Zhang

    2016-02-01

    Full Text Available Background/Aims: Tempol is a protective antioxidant against ischemic injury in many animal models. The molecular mechanisms are not well understood. Nuclear factor erythroid 2-related factor (Nrf2 is a master transcription factor during oxidative stress, which is enhanced by activation of protein kinase C (PKC pathway. Another factor, tubular epithelial apoptosis, is mediated by activation of phosphoinositide 3-kinase (PI3K/protein kinase B (PKB, Akt signaling pathway during renal ischemic injury. We tested the hypothesis that tempol activates PKC or PI3K/Akt/Nrf2 pathways to transcribe many genes that coordinate endogenous antioxidant defense. Methods: The right renal pedicle was clamped for 45 minutes and the left kidney was removed to study renal ischemia/reperfusion (I/R injury in C57BL/6 mice. The response was assessed from serum parameters, renal morphology and renal expression of PKC, phosphorylated-PKC (p-PKC, Nrf2, heme oxygenase-1 (HO-1, Akt, phosphorylated-Akt (p-Akt, pro-caspase-3 and cleaved caspase-3 in groups of sham and I/R mice given vehicle, or tempol (50 or 100 mg/kg, intraperitoneal injection. Results: The serum malondialdehyde (MDA, marker of reactive oxygen species doubled and the BUN and creatinine increased 5- to 10-fold after I/R injury. Tempol (50 or 100 mg/kg prevented the increases in MDA but only tempol (50 mg/kg lessened the increases in BUN and creatinine and moderated the acute tubular necrosis. I/R did not change expression of PKC or p-PKC but reduced renal expression of Nrf2, p-Akt, HO-1 and pro-caspase-3 and increased cleaved caspase-3. Tempol (50 mg/kg prevented these changes produced by I/R whereas tempol (100 mg/kg had lesser or inconsistent effects. Conclusion: Tempol (50 mg/kg prevents lipid peroxidation and attenuates renal damage after I/R injury. The beneficial pathway apparently is not dependent on upregulation or phosphorylation of PKC, at lower tempol doses, does implicate upregulation of Akt with

  13. The roles of PI3K/Akt signaling pathway in regulating MC3T3-E1 preosteoblast proliferation and differentiation on SLA and SLActive titanium surfaces.

    Science.gov (United States)

    Gu, Ying-Xin; Du, Juan; Si, Mi-Si; Mo, Jia-Ji; Qiao, Shi-Chong; Lai, Hong-Chang

    2013-03-01

    Chemical modification to produce a hydrophilic microrough titanium (Ti) implant surface has been shown to increase osseointegration compared with microrough topography alone. This study aimed to investigate the roles of PI3K/Akt signaling pathway in regulating proliferation and differentiation of osteoblasts in response to surface microroughness and hydrophilicity. Ti disks were manufactured to present different surface morphologies: a smooth pretreatment surface (PT), a rough hydrophobic surface that was sand-blasted, large-grit, acid-etched (SLA), and an SLA surface with the same roughness that was chemically modified to possess high wettability/hydrophilicity (SLActive/modSLA). MC3T3-E1 cells were cultured on these substrates with or without LY294002, a PI3K inhibitor, and their behaviors, including cell viability (MTT colorimetric assay), alkaline phosphatase (ALP) activity, and osteogenic genes expression of osteopontin (OPN) and osteocalcin (OCN) were measured. Western blot was applied to detect the expression of PI3K/Akt signal pathway proteins. The results showed that a decrease in osteoblast proliferation associated with the Ti surfaces (SLActive > SLA > PT) correlated with an increase in activity of the osteogenic differentiation markers ALP. The peak of ALP activity appeared earlier at 7 days for the SLActive surfaces compared with the SLA and PT surfaces. Osteoblast proliferation, as well as the level of p-Akt, was significantly inhibited by LY294002 in all three Ti surfaces. The top value of ALP activity was increased with the inhibition of PI3K/Akt signaling pathway while the time of the peak appeared was not advanced. The expression levels of OPN and OCN were upregulated by the effect of surface roughness and hydrophilicity, which were further enhanced by LY294002. In conclusion, osteogenic responses to SLActive surface were moderately better than the SLA surface and protein expression studies indicated that PI3K/Akt signaling activation may be

  14. MAPK/ERK和PI3K/Akt信号通道的基因变异与甲状腺癌的发生发展及诊治%Genetic Alterations in MAPK and PI3K/Akt Signaling Pathways and the Generation, Progression, Diagnosis and Therapy of Thyroid Cancer

    Institute of Scientific and Technical Information of China (English)

    刘斌

    2012-01-01

    通过将细胞外信号转导至细胞核内,丝裂原活化蛋白激酶(MAPK)和磷脂酰肌醇-3羟基激酶/蛋白激酶B(PI3K/Akt)信号通道在细胞的生长、增殖及凋亡等活动中发挥着重要的调节作用.甲状腺癌细胞MAPK/ERK和PI3K/Akt信号通道蛋白的编码基因多异常表达.基因变异致MAPK/ERK和PI3K/Akt信号通道的过度活化及相互作用,与甲状腺癌的发生及进展密切相关.本文主要就MAPK和PI3K/Akt信号通道的基因变异在甲状腺癌发生、进展及诊断中的作用作一综述.此外,本文还将探讨同步抑制MAPK和PI3K/Akt信号通道,恢复细胞的摄碘能力,介导放射性核素靶向治疗甲状腺癌的治疗潜力.%The mitogen-activated protein kinase/extracellular signal-regulated kinase ( MAPK/ERK ) and phoshoinositide-3-kinase/protein kinase B (PI3K/Akt) signaling pathways play a major role in regulating cell growth, proliferation and apoptosis, via transmission of cell signals to cell nucleus. The genes, coding the MAPK/ ERK and PI3K/Akt signaling cascade proteins, are significantly mutated in thyroid cancer. Genetic alternations contribute to aberrant activations and interaction of MAPK/ERK and PI3K/Akt signaling pathways in consequence of malignant follicular cell transformation and progression. This review focuses mainly on the role of genetic alterations in coding MAPK/ERK and PI3K/Akt signaling pathway proteins in generation, progression and diagnosis of thyroid cancer. Moreover, it additionally points out a therapeutic potential in restoring iodine avidity of thyroid cancer cells for radionuclide targeted treatment, by synergistically inhibiting activity of signaling pathways.

  15. JNK/PI3K/Akt signaling pathway is involved in myocardial ischemia/reperfusion injury in diabetic rats: effects of salvianolic acid A intervention.

    Science.gov (United States)

    Chen, Qiuping; Xu, Tongda; Li, Dongye; Pan, Defeng; Wu, Pei; Luo, Yuanyuan; Ma, Yanfeng; Liu, Yang

    2016-01-01

    Recent studies have demonstrated that diabetes impairs the phosphatidylinositol 3-kinase/Akt (PI3K/Akt) pathway, while insulin resistance syndrome has been associated with alterations of this pathway in diabetic rats after ischemia/reperfusion (I/R), and activation of C-jun N-terminal kinase (JNK) is involved. The present study was designed to investigate whether inhibiting JNK activity would partially restore the PI3K/Akt signaling pathway and protect against myocardial I/R injury in diabetic rats, and to explore the effect of intervention with salvianolic acid A (Sal A). The inhibitor of JNK (SP600125) and Sal A were used in type 2 diabetic (T2D) rats, outcome measures included heart hemodynamic data, myocardial infarct size, the release of lactate dehydrogenase (LDH), SERCA2a activity, cardiomyocyte apotosis, expression levels of Bcl-2, Bax and cleaved caspase-3, and the phosphorylation status of Akt and JNK. The p-Akt levels were increased after myocardial I/R in non-diabetic rats, while there was no change in diabetic rats. Pretreatment with the SP600125 and Sal A decreased the p-JNK levels and increased the p-Akt levels in diabetic rats with I/R, and heart hemodynamic data improved, infarct size and LDH release decreased, SERCA2a activity increased, Bax and cleaved caspase-3 expression levels decreased, and the expression of Bcl-2 and the Bcl-2/Bax ratio increased. Our results suggest that the JNK/PI3K/Akt signaling pathway is involved in myocardial I/R injury in diabetic rats and Sal A exerts an anti-apoptotic effect and improves cardiac function following I/R injury through the JNK/PI3K/Akt signaling pathway in this model.

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

    Directory of Open Access Journals (Sweden)

    Duan J

    2014-11-01

    Full Text Available Junchao Duan,1,2 Yongbo Yu,1,2 Yang Yu,1,2 Yang Li,1,2 Ji Wang,1,2 Weijia Geng,1,2 Lizhen Jiang,1,2 Qiuling Li,1,2 Xianqing Zhou,1,2 Zhiwei Sun1,2 1School of Public Health, Capital Medical University, Beijing, 2Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing, People’s Republic of China Abstract: Although nanoparticles have a great potential for biomedical applications, there is still a lack of a correlative safety evaluation on the cardiovascular system. This study is aimed to clarify the biological behavior and influence of silica nanoparticles (Nano-SiO2 on endothelial cell function. The results showed that the Nano-SiO2 were internalized into endothelial cells in a dose-dependent manner. Monodansylcadaverine staining, autophagic ultrastructural observation, and LC3-I/LC3-II conversion were employed to verify autophagy activation induced by Nano-SiO2, and the whole autophagic process was also observed in endothelial cells. In addition, the level of nitric oxide (NO, the activities of NO synthase (NOS and endothelial (eNOS were significantly decreased in a dose-dependent way, while the activity of inducible (iNOS was markedly increased. The expression of C-reactive protein, as well as the production of proinflammatory cytokines (tumor necrosis factor α, interleukin [IL]-1β, and IL-6 were significantly elevated. Moreover, Nano-SiO2 had an inhibitory effect on the phosphoinositide 3-kinase (PI3K/protein kinase B (Akt/mammalian target of rapamycin (mTOR signaling pathway. Our findings demonstrated that Nano-SiO2 could disturb the NO/NOS system, induce inflammatory response, activate autophagy, and eventually lead to endothelial dysfunction via the PI3K/Akt/mTOR pathway. This indicates that exposure to Nano-SiO2 is a potential risk factor for cardiovascular diseases. Keywords: silica nanoparticles, endothelial dysfunction, autophagy, nitric oxide, inflammation

  17. Frequent alterations of the PI3K/AKT/mTOR pathways in hereditary nonpolyposis colorectal cancer

    DEFF Research Database (Denmark)

    Ekstrand, Anna Isinger; Jönsson, Mats; Lindblom, Annika;

    2010-01-01

    The phosphatidylinositol 3-kinases-AKT-mammalian target of rapamycin pathway (PI3K/AKT/mTOR) is central in colorectal tumors. Data on its role in hereditary cancers are, however, scarce and we therefore characterized mutations in PIK3CA and KRAS, and expression of PIK3CA, phosphorylated AKT...... and PTEN in 58 HNPCC-associated colorectal cancers. Derangements of at least one of the PI3K/AKT/mTOR components analyzed were found in 51/58 (88%) tumors. Mutations in PIK3CA and KRAS were identified in 14 and 31% of the tumors respectively. Overexpression of PIK3CA and phosphorylated AKT occurred in 59...... and 75% and were strongly associated (P = 0.005). Reduced/lost PTEN expression was found in 63% of the tumors. Though HNPCC-associated colorectal cancers show simple genetic profiles with few chromosomal alterations, we demonstrate frequent and repeated targeting of the PI3K/AKT/mTOR pathway, which...

  18. GRANULOCYTE COLONY-STIMULATING FACTOR (G-CSF) UPREGULATES β1 INTEGRIN AND INCREASES MIGRATION OF HUMAN TROPHOBLAST SWAN 71 CELLS VIA PI3K AND MAPK ACTIVATION

    Science.gov (United States)

    Furmento, Verónica A.; Marino, Julieta; Blank, Viviana C.; Cayrol, María Florencia; Cremaschi, Graciela A.; Aguilar, Rubén C.; Roguin, Leonor P.

    2017-01-01

    Multiple cytokines and growth factors expressed at the fetal-maternal interface are involved in the regulation of trophoblast functions and placental growth, but the role of G-CSF has not been completely established. Based on our previous study showing that G-CSF increases the activity of matrix metalloproteinase-2 and the release of vascular endothelial growth factor in Swan 71 human trophoblast cells, in this work we explore the possible contribution of G-CSF to cell migration and the G-CSF-triggered signaling pathway. We found that G-CSF induced morphological changes on actin cytoskeleton consistent with a migratory cell phenotype. G-CSF also up-regulated the expression levels of β1 integrin and promoted Swan 71 cell migration. By using selective pharmacological inhibitors and dominant negative mutants we showed that PI3K, Erk 1/2 and p38 pathways are required for promoting Swan 71 cell motility. It was also demonstrated that PI3K behaved as an upstream regulator of Erk 1/2 and p38 MAPK. In addition, the increase of β1 integrin expression was dependent on PI3K activation. In conclusion, our results indicate that G-CSF stimulates β1 integrin expression and Swan 71 cell migration by activating PI3K and MAPK signaling pathways, suggesting that G-CSF should be considered as an additional regulatory factor that contributes to a successful embryo implantation and to the placenta development. PMID:26992288

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  1. The Effect of Tianmai Xiaoke Pian on Insulin Resistance through PI3-K/AKT Signal Pathway

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    Nana Wang

    2016-01-01

    Full Text Available In the clinical setting, given the potential adverse effects of thiazolidinediones and biguanides, we often have difficulty in treatment that no other insulin sensitizers are available for use in type 2 diabetic mellitus (T2DM patients. Tianmai Xiaoke Pian (TMXKP is a traditional Chinese medicine tablet, which is comprised of chromium picolinate, Tianhuafen, Maidong, and Wuweizi. To understand its mechanism of action on insulin resistance, TMXKP (50 mg/kg orally was tested in T2DM rats (induced by a high-fat diet and streptozotocin. Eight weeks later, fasting blood glucose (FBG and oral glucose tolerance tests (OGTT were performed. Area under the curve (AUC and homeostatic model assessment of insulin resistance (HOMA-IR were calculated, and PI3-K/AKT signal pathway-related genes and proteins were tested by reverse transcription-polymerase chain reaction (RT-PCR and western blot analysis in muscle, adipose, and liver tissues, respectively. TMXKP significantly reduced FBG, OGTT, AUC, and HOMA-IR in diabetic rats P<0.05. Furthermore, we also observed that TMXKP could significantly decrease IRS-1, IRS-2, PI3-K p85α, and AKT2 gene expression and also IRS-1, IRS-2, PI3-K, AKT2, and p-AKT2 protein expression levels P<0.05 in diabetic rats. These findings confirm that TMXKP can alleviate insulin resistance in T2DM rats through the PI3K/AKT pathway. Thus TMXKP appears to be a promising insulin sensitizer.

  2. Cell entry of bovine ephemeral fever virus requires activation of Src-JNK-AP1 and PI3K-Akt-NF-κB pathways as well as Cox-2-mediated PGE2 /EP receptor signalling to enhance clathrin-mediated virus endocytosis.

    Science.gov (United States)

    Cheng, Ching-Yuan; Huang, Wei-Ru; Chi, Pei-I; Chiu, Hung-Chuan; Liu, Hung-Jen

    2015-07-01

    Although we have previously demonstrated that cell entry of bovine ephemeral fever virus (BEFV) follows a clathrin-mediated and dynamin 2-dependent endocytosis pathway, the cellular mechanism mediating virus entry remains unknown. Here, we report that BEFV triggers simultaneously Src-JNK-AP1 and PI3K-Akt-NF-κB signalling pathways in the stage of virus binding to induce clathrin and dynamin 2 expressions, while vesicular stomatitis virus only activates Src-JNK signalling to enhance its entry. Activation of these pathways by ultraviolet-inactivated BEFV suggests a role for virus binding but not viral internalization and gene expression. By blocking these signalling pathways with specific inhibitors, BEFV-induced expressions of clathrin and dynamin 2 were significantly diminished. By labelling BEFV with 3,3'-dilinoleyloxacarbocyanine perchlorate to track viral entry, we found that virus entry was hindered by both Src and Akt inhibitors, suggesting that these signalling pathways are crucial for efficient virus entry. In addition, BEFV also triggers Cox-2-catalysed prostaglandin E2 (PGE2) synthesis and induces expressions of G-protein-coupled E-prostanoid (EP) receptors 2 and 4, leading to amplify signal cascades of Src-JNK-AP1 and PI3K-Akt-NF-κB, which elevates both clathrin and dynamin 2 expressions. Furthermore, pretreatment of cells with adenylate cyclase (cAMP) inhibitor SQ22536 reduced BEFV-induced Src phosphorylation as well as clathrin and dynamin 2 expressions. Our findings reveal for the first time that BEFV activates the Cox-2-mediated PGE2/EP receptor signalling pathways, further enhancing Src-JNK-AP1 in a cAMP-dependent manner and PI3K-Akt-NF-κB in a cAMP-independent manner. Accordingly, BEFV stimulates PGE2/EP receptor signalling amplifying Src-JNK-AP1 and PI3K-Akt-NF-κB pathways in an autocrine or paracrine fashion to enhance virus entry. © 2015 John Wiley & Sons Ltd.

  3. PAR1- and PAR2-induced innate immune markers are negatively regulated by PI3K/Akt signaling pathway in oral keratinocytes

    Directory of Open Access Journals (Sweden)

    Dale Beverly A

    2010-10-01

    Full Text Available Abstract Background Protease-Activated Receptors (PARs, members of G-protein-coupled receptors, are activated by proteolytic activity of various proteases. Activation of PAR1 and PAR2 triggers innate immune responses in human oral keratinocytes (HOKs, but the signaling pathways downstream of PAR activation in HOKs have not been clearly defined. In this study, we aimed to determine if PAR1- and PAR2-mediated signaling differs in the induction of innate immune markers CXCL3, CXCL5 and CCL20 via ERK, p38 and PI3K/Akt. Results Our data show the induction of innate immunity by PAR1 requires both p38 and ERK MAP kinases, while PAR2 prominently signals via p38. However, inhibition of PI3K enhances expression of innate immune markers predominantly via suppressing p38 phosphorylation signaled by PAR activation. Conclusion Our data indicate that proteases mediating PAR1 and PAR2 activation differentially signal via MAP kinase cascades. In addition, the production of chemokines induced by PAR1 and PAR2 is suppressed by PI3K/Akt, thus keeping the innate immune responses of HOK in balance. The results of our study provide a novel insight into signaling pathways involved in PAR activation.

  4. Targeting the cell cycle and the PI3K pathway: a possible universal strategy to reactivate innate tumor suppressor programmes in cancer cells.

    Science.gov (United States)

    David-Pfeuty, Thérèse; Legraverend, Michel; Ludwig, Odile; Grierson, David S

    2010-04-01

    Corruption of the Rb and p53 pathways occurs in virtually all human cancers. This could be because it lends oncogene-bearing cells a surfeit of Cdk activity and growth, enabling them to elaborate strategies to evade tumor-suppressive mechanisms and divide inappropriately. Targeting both Cdk activities and the PI3K pathway might be therefore a potentially universal means to palliate their deficiency in cancer cells. We showed that the killing efficacy of roscovitine and 16 other purines and potentiation of roscovitine-induced apoptosis by the PI3K inhibitor, LY294002, decreased with increasing corruption of the Rb and p53 pathways. Further, we showed that purines differing by a single substitution, which exerted little lethal effect on distant cell types in rich medium, could display widely-differing cytotoxicity profiles toward the same cell types in poor medium. Thus, closely-related compounds targeting similar Cdks may interact with different targets that could compete for their interaction with therapeutically-relevant Cdk targets. In the perspective of clinical development in association with the PI3K pathway inhibitors, it might thus be advisable to select tumor cell type-specific Cdk inhibitors on the basis of their toxicity in cell-culture-based assays performed at a limiting serum concentration sufficient to suppress their interaction with undesirable crossreacting targets whose range and concentration would depend on the cell genotype.

  5. The PI3K/Akt Signaling Pathway Mediates the High Glucose-Induced Expression of Extracellular Matrix Molecules in Human Retinal Pigment Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Dong Qin

    2015-01-01

    Full Text Available Prolonged hyperglycemia is an important risk factor of the pathogenesis of diabetic retinopathy (DR. Extracellular matrix molecules, such as fibronectin, collagen IV, and laminin, are associated with fibrotic membranes. In this study, we investigated the expression of fibronectin, collagen IV, and laminin in RPE cells under high glucose conditions. Furthermore, we also detected the phosphorylation of protein kinase B (Akt under high glucose conditions in RPE cells. Our results showed that high glucose upregulated fibronectin, collagen IV, and laminin expression, and activated Akt in RPE cells. We also found that pretreatment with LY294002 (an inhibitor of phosphatidylinositol 3-kinase abolished high glucose-induced expression of fibronectin, collagen IV, and laminin in RPE cells. Thus, high glucose induced the expression of fibronectin, collagen IV, and laminin through PI3K/Akt signaling pathway in RPE cells, and the PI3K/Akt signaling pathway may contribute to the formation of fibrotic membrane during the development of DR.

  6. Involvement of cAMP/Epac/PI3K-dependent pathway in the antiproteolytic effect of epinephrine on rat skeletal muscle.

    Science.gov (United States)

    Baviera, Amanda Martins; Zanon, Neusa Maria; Navegantes, Luiz Carlos C; Kettelhut, Isis Carmo

    2010-02-05

    Very little is known about the signaling pathways by which catecholamines exert anabolic effects on muscle protein metabolism, stimulating protein synthesis and suppressing proteolysis. The present work tested the hypothesis that epinephrine-induced inhibition of muscle proteolysis is mediated through the cAMP/Epac/PI3K-dependent pathway with the involvement of AKT and Foxo. The incubation of extensor digitorum longus (EDL) muscles from rats with epinephrine and/or insulin increased the phosphorylation of AKT and its downstream target Foxo3a, a well-known effect that prevents Foxo translocation to the nucleus and the activation of proteolysis. Similar effects on AKT/Foxo signaling were observed in muscles incubated with DBcAMP (cAMP analog). The stimulatory effect of epinephrine on AKT phosphorylation was completely blocked by wortmannin (selective PI3K inhibitor), suggesting that the epinephrine-induced activation of AKT is mediated through PI3K. As for epinephrine and DBcAMP, the incubation of muscles with 8CPT-2Me-cAMP (selective Epac agonist) reduced rates of proteolysis and increased phosphorylation levels of AKT and Foxo3a. The specific PKA agonist (N6BZ-cAMP) inhibited proteolysis and abolished the epinephrine-induced AKT and Foxo3a phosphorylation. On the other hand, inhibition of PKA by H89 further increased the phosphorylation levels of AKT and Foxo3a induced by epinephrine, DBcAMP or 8CPT-2Me-cAMP. These findings suggest that the antiproteolytic effect of the epinephrine on isolated skeletal muscle may occur through a cAMP/Epac/PI3K-dependent pathway, which leads to the phosphorylation of AKT and Foxo3a. The parallel activation of PKA-dependent pathway also inhibits proteolysis and seems to limit the stimulatory effect of cAMP on AKT/Foxo3a signaling.

  7. Mechanical Stress Regulates Osteogenesis and Adipogenesis of Rat Mesenchymal Stem Cells through PI3K/Akt/GSK-3β/β-Catenin Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Fanglong Song

    2017-01-01

    Full Text Available Osteogenesis and adipogenesis of bone marrow mesenchymal stem cells (BMSCs are regarded as being of great importance in the regulation of bone remodeling. In this study, rat BMSCs were exposed to different levels of cyclic mechanical stress generated by liquid drops and cultured in general medium or adipogenic medium. Markers of osteogenic (Runx2 and Collagen I and adipogenic (C/EBPα, PPARγ, and lipid droplets differentiation were detected using Western blot and histological staining. The protein levels of members of the phosphatidylinositol 3-kinase (PI3K/Akt/glycogen synthase kinase 3β (GSK-3β/β-catenin signaling pathway were also examined. Results showed that small-magnitude stress significantly upregulated Runx2 and Collagen I and downregulated PPARγ and C/EBPα expression in BMSCs cultured in adipogenic medium, while large-magnitude stress reversed the effect when compared with unloading groups. The PI3K/Akt signaling pathway could be strongly activated by mechanical stimulation; however, large-magnitude stress led to decreased activation of the signaling pathway when compared with small-magnitude stress. Activation of β-catenin with LiCl led to increased expression of Runx2 and Collagen I and reduction of C/EBPα and PPARγ expression in BMSCs. Inhibition of PI3K/Akt signaling partially blocked the expression of β-catenin. Taken together, our results indicate that mechanical stress-regulated osteogenesis and adipogenesis of rat BMSCs are mediated, at least in part, by the PI3K/Akt/GSK-3β/β-catenin signaling pathway.

  8. Constitutively activated PI3K accelerates tumor initiation and modifies histopathology of breast cancer.

    Science.gov (United States)

    Sheen, M R; Marotti, J D; Allegrezza, M J; Rutkowski, M; Conejo-Garcia, J R; Fiering, S

    2016-10-31

    The gene encoding phosphatidylinositol 3-kinase catalytic subunit α-isoform (PIK3CA, p110α) is frequently activated by mutation in human cancers. Based on detection in some breast cancer precursors, PIK3CA mutations have been proposed to have a role in tumor initiation. To investigate this hypothesis, we generated a novel mouse model with a Cre-recombinase regulated allele of p110α (myristoylated-p110α, myr-p110α) along with p53(fl/fl) deletion and Kras(G12D) also regulated by Cre-recombinase. After instillation of adenovirus-expressing Cre-recombinase into mammary ducts, we found that myr-p110α accelerated breast tumor initiation in a copy number-dependent manner. Breast tumors induced by p53(fl/fl);Kras(G12D) with no or one copy of myr-p110α had predominantly sarcomatoid features, whereas two copies of myr-p110α resulted in tumors with a carcinoma phenotype. This novel model provides experimental support for importance of active p110α in breast tumor initiation, and shows that the amount of PI3K activity can affect the rate of tumor initiation and modify the histological phenotype of breast cancer.

  9. Naringin inhibits TNF-α induced oxidative stress and inflammatory response in HUVECs via Nox4/NF-κ B and PI3K/Akt pathways.

    Science.gov (United States)

    Li, Wenshuang; Wang, Changyuan; Peng, Jinyong; Liang, Jing; Jin, Yue; Liu, Qi; Meng, Qiang; Liu, Kexin; Sun, Huijun

    2014-01-01

    In the development of atherosclerosis, naringin has exhibited potential protective effects. However, the specific mechanisms are not clearly understood. The aim of this trial was to determine the anti-oxidative and anti-inflammatory effects of naringin and uncover the mechanisms in Tumor Necrosis Factor-alpha (TNF-α) induced Human Umbilical Vein Endothelial Cells (HUVECs). Reactive Oxygen Species (ROS) were measured by flow cytometry assay. The levels of NADPH oxidase 4 (Nox4), p22(phox), intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) over-expressions were measured by qRT-PCR and Western blotting analyses. Activation of Phosphatidylinositol 3-kinase/Akt (PI3K/Akt) and Nuclear Factor-κB (NF-κB) was evaluated by Western blotting. Naringin inhibited ROS production as well as over-expression levels of Nox4, p22(phox) induced by TNF-α. Naringin inhibited TNF-α induced mRNA and protein over-expressions of ICAM-1 and VCAM-1. Naringin also suppressed activation of NF-κB and PI3K/Akt signaling pathways. These results indicated the preventive effects of naringin on HUVECs injury caused by oxidative stress and inflammation response and the effects might be obtained via inhibition of Nox4 and NF-κB pathways as well as activation of PI3K/Akt pathway. Naringin may be useful in preventing endothelial dysfunction, therefore to ameliorate the development of atherosclerosis.

  10. Blockage of PI3K/PKB/P27kip1 signaling pathway can antagonize 17β-estradiol-induced Ishikawa proliferation and cell cycle progression

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ It is well-known that risk for endometrial adenocar- cinoma increases in patients with high level of estrogen that is unopposed by progestin. And activation of extracellular signal-regulated kinase (ERK)1 and phosphatidylinositol 3 kinase/protein kinase B (PI3K/PKB) pathway are responsible for hormone-dependent cell growth in endometrial carcinoma.2-4 PI3K produces phosphatidylinositol- 3-phosphates by phosphory- lating the D3 hydroxyl of phosphoinositides, leading to membrane translocation of PKB, on which PKB is phosphorylated and activated. Then the activated PKB can stimulate antiapoptotic cellular responses and block apoptotic functions of the cells, thus regulate the apoptosis and proliferation of cell, cell cycle progression, glucose usage, and angiogenesis.

  11. Placental growth factor enhances angiogenesis in human intestinal microvascular endothelial cells via PI3K/Akt pathway: Potential implications of inflammation bowel disease

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Yi, E-mail: mondayzy@126.com; Tu, Chuantao, E-mail: tu.chuantao@zs-hospital.sh.cn; Zhao, Yuan, E-mail: zhao.yuan@zs-hospital.sh.cn; Liu, Hongchun, E-mail: liuhch@aliyun.com; Zhang, Shuncai, E-mail: zhang.shuncai@zs-hospital.sh.cn

    2016-02-19

    Background: Angiogenesis plays a major role in the pathogenesis of inflammatory bowel disease (IBD). Placental growth factor (PlGF) is a specific regulator of pathological angiogenesis and is upregulated in the sera of IBD patients. Therefore, the role of PlGF in IBD angiogenesis was investigated here using HIMECs. Methods: The expression of PlGF and its receptors in human intestinal microvascular endothelial cells (HIMECs) and inflamed mucosa of IBD patients were examined using quantitative PCR and western blot analysis and the role of PlGF in IBD HIMECs was further explored using small interfering RNA (siRNA). The induction of pro-inflammatory cytokine by PlGF in HIMECs was confirmed by ELISA. The capacity of PlGF to induce angiogenesis in HIMECs was tested through proliferation, cell-migration, matrigel tubule-formation assays and its underlying signaling pathway were explored by western blot analysis of ERK1/2 and PI3K/Akt phosphorylation. Results: mRNA and protein expression of PlGF and its receptor NRP-1 were significantly increased in IBD HIMECs. Inflamed mucosa of IBD patients also displayed higher expression of PIGF. The production of IL-6 and TNF-α in culture supernatant of HIMECs treated with exogenous recombinant human PlGF-1 (rhPlGF-1) were increased. Furthermore, rhPlGF-1 significantly induced HIMECs migration and tube formation in a dose-dependent manner and knockdown of endogenous PlGF in IBD HIMECs using siRNA substantially reduced these angiogenesis activities. PlGF induced PI3K/Akt phosphorylation in HIMECs and pretreatment of PlGF-stimulated HIMECs with PI3K inhibitor (LY294002) significantly inhibited the PlGF-induced cell migration and tube formation. Conclusion: Our results demonstrated the pro-inflammatory and angiogenic effects of PlGF on HIMECs in IBD through activation of PI3K/Akt signaling pathway. PlGF/PI3K/Akt signaling may serve as a potential therapeutic target for IBD. - Highlights: • Expression of PlGF and its receptor NRP-1

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

    Science.gov (United States)

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

    2014-02-01

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

  13. BMX Acts Downstream of PI3K to Promote Colorectal Cancer Cell Survival and Pathway Inhibition Sensitizes to the BH3 Mimetic ABT-737

    Directory of Open Access Journals (Sweden)

    Danielle S. Potter

    2014-02-01

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

  14. Oleanolic acid inhibits cell survival and proliferation of prostate cancer cells in vitro and in vivo through the PI3K/Akt pathway.

    Science.gov (United States)

    Li, Xuechao; Song, Yarong; Zhang, Peng; Zhu, Hongxue; Chen, Lifeng; Xiao, Yajun; Xing, Yifei

    2016-06-01

    Oleanolic acid (OA) is a naturally occurring pentacyclic triterpenoid and possesses diverse pharmacological activities, including anti-cancer effects that have been confirmed in multiple types of human cancers. However, the potential effect of natural OA on human prostate cancer is still unclear. The present study aimed to explore whether and how OA exerted anti-cancer effects in prostate cancer. Our data showed that OA inhibited cell viability and proliferation, and promoted cell apoptosis and G0/G1 phase cell cycle arrest in prostate cancer PC-3, DU145, and LNCaP cells, in a dose-dependent manner. In addition, OA was found to regulate the expression levels of apoptosis-related and cell cycle-related proteins, as well as the activity of PI3K/Akt pathway, in a dose-dependent manner. Mechanistically, our data revealed that OA exerted anti-cancer effects in vitro in PC-3 and DU145 cells by repressing the PI3K/Akt pathway. In agreement, OA also suppressed the tumor growth of PC-3 cells in vivo via inhibition of the PI3K/Akt pathway. In conclusion, our findings demonstrate the anti-cancer properties of OA in prostate cancer cells, both in vitro and in vivo, and provide the experimental evidence for the use of OA as an adjuvant agent for prostate cancer patients.

  15. Metastatic function of BMP-2 in gastric cancer cells: The role of PI3K/AKT, MAPK, the NF-{kappa}B pathway, and MMP-9 expression

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Myoung Hee [Graduate School of Medicine, Korea University College of Medicine, Korea University, Seoul 136-705 (Korea, Republic of); Oh, Sang Cheul [Division of Oncology/Hematology, Department of Internal Medicine, Korea University College of Medicine, Korea University, Seoul 136-705 (Korea, Republic of); Lee, Hyun Joo [Department of Pathology, Korea University College of Medicine, Korea University, Seoul 136-705 (Korea, Republic of); Kang, Han Na; Kim, Jung Lim [Graduate School of Medicine, Korea University College of Medicine, Korea University, Seoul 136-705 (Korea, Republic of); Kim, Jun Suk [Division of Oncology/Hematology, Department of Internal Medicine, Korea University College of Medicine, Korea University, Seoul 136-705 (Korea, Republic of); Yoo, Young A., E-mail: ydanbi@korea.ac.kr [Brain Korea 21 Program for Biomedical Science, Korea University College of Medicine, Korea University, Seoul 136-705 (Korea, Republic of)

    2011-07-15

    Bone morphogenetic proteins (BMPs) have been implicated in tumorigenesis and metastatic progression in various types of cancer cells, but the role and cellular mechanism in the invasive phenotype of gastric cancer cells is not known. Herein, we determined the roles of phosphoinositide 3-kinase (PI3K)/AKT, extracellular signal-regulated protein kinase (ERK), nuclear factor (NF)-{kappa}B, and matrix metalloproteinase (MMP) expression in BMP-2-mediated metastatic function in gastric cancer. We found that stimulation of BMP-2 in gastric cancer cells enhanced the phosphorylation of AKT and ERK. Accompanying activation of AKT and ERK kinase, BMP-2 also enhanced phosphorylation/degradation of I{kappa}B{alpha} and the nuclear translocation/activation of NF-{kappa}B. Interestingly, blockade of PI3K/AKT and ERK signaling using LY294002 and PD98059, respectively, significantly inhibited BMP-2-induced motility and invasiveness in association with the activation of NF-{kappa}B. Furthermore, BMP-2-induced MMP-9 expression and enzymatic activity was also significantly blocked by treatment with PI3K/AKT, ERK, or NF-{kappa}B inhibitors. Immunohistochemistry staining of 178 gastric tumor biopsies indicated that expression of BMP-2 and MMP-9 had a significant positive correlation with lymph node metastasis and a poor prognosis. These results indicate that the BMP-2 signaling pathway enhances tumor metastasis in gastric cancer by sequential activation of the PI3K/AKT or MAPK pathway followed by the induction of NF-{kappa}B and MMP-9 activity, indicating that BMP-2 has the potential to be a therapeutic molecular target to decrease metastasis.

  16. Selective inhibition of PI3K/Akt/mTOR signaling pathway regulates autophagy of macrophage and vulnerability of atherosclerotic plaque.

    Directory of Open Access Journals (Sweden)

    Chungang Zhai

    Full Text Available Macrophage infiltration contributes to the instability of atherosclerotic plaques. In the present study, we investigated whether selective inhibition of PI3K/Akt/mTOR signaling pathway can enhance the stability of atherosclerotic plaques by activation of macrophage autophagy. In vitro study, selective inhibitors or siRNA of PI3K/Akt/mTOR pathways were used to treat the rabbit's peritoneal primary macrophage cells. Inflammation related cytokines secreted by macrophages were measured. Ultrastructure changes of macrophages were examined by transmission electron microscope. mRNA or protein expression levels of autophagy related gene Beclin 1, protein 1 light chain 3 II dots (LC3-II or Atg5-Atg12 conjugation were assayed by quantitative RT-PCR or Western blot. In vivo study, vulnerable plaque models were established in 40 New Zealand White rabbits and then drugs or siRNA were given for 8 weeks to inhibit the PI3K/Akt/mTOR signaling pathway. Intravascular ultrasound (IVUS was performed to observe the plaque imaging. The ultrastructure of the abdominal aortic atherosclerosis lesions were analyzed with histopathology. RT-PCR or Western blot methods were used to measure the expression levels of corresponding autophagy related molecules. We found that macrophage autophagy was induced in the presence of Akt inhibitor, mTOR inhibitor and mTOR-siRNA in vitro study, while PI3K inhibitor had the opposite role. In vivo study, we found that macrophage autophagy increased significantly and the rabbits had lower plaque rupture incidence, lower plaque burden and decreased vulnerability index in the inhibitors or siRNA treated groups. We made a conclusion that selective inhibition of the Akt/mTOR signal pathway can reduce macrophages and stabilize the vulnerable atherosclerotic plaques by promoting macrophage autophagy.

  17. Esculetin induces apoptosis of SMMC-7721 cells through IGF-1/PI3K/Akt-mediated mitochondrial pathways.

    Science.gov (United States)

    Li, Juan; Li, Shuang; Wang, Xiuli; Wang, Hongxin

    2017-07-01

    Esculetin (6,7-dihydroxycoumarin) is a coumarin derivative extracted from natural plants and has been reported to have anticancer activity. However, the mechanism by which esculetin prevents human hepatic cancer cell growth is still largely unknown. In this study, we investigated the effect of esculetin on human hepatocellular carcinoma (HCC) SMMC-7721 cells and explored the cell signal mechanism. Our data indicated that esculetin induced apoptosis in SMMC-7721 cells, which were supported by DAPI staining and Annexin V/PI staining. Meanwhile, esculetin increased the activities of caspase-3 and caspase-9, promoted bax expression, decreased bcl-2 expression, and triggered collapse of mitochondrial membrane potential, and increased cytochrome c release from mitochondria. In addition, the inactivation of IGF-1, PI3K, and Akt was observed after esculetin administration. Furthermore, pretreatment with IGF-1 before esculetin administration abrogated the pro-apoptotic effects of esculetin, while PI3K inhibitor increased the pro-apoptotic effects of esculetin. These results indicated that esculetin induced the apoptosis of SMMC-7721 cells through IGF-1/PI3K/Akt-regulated mitochondrial dysfunction.

  18. Mefloquine effectively targets gastric cancer cells through phosphatase-dependent inhibition of PI3K/Akt/mTOR signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yanwei [Department of General Surgery, Shiyan Taihe Hospital, Hubei University of Medicine, Shiyan, Hubei Province (China); Chen, Sen [Department of Academic Affairs, Hubei University of Medicine, Shiyan, Hubei Province (China); Xue, Rui [Department of Anesthesiology, Renmin Hospital, Hubei University of Medicine, Shiyan, Hubei Province (China); Zhao, Juan [Department of Oncology, Xiangyang Central Hospital, Shiyan, Hubei Province (China); Di, Maojun, E-mail: maoojun_di@163.com [Department of General Surgery, Shiyan Taihe Hospital, Hubei University of Medicine, Shiyan, Hubei Province (China)

    2016-02-05

    Deregulation of PI3K/Akt/mTOR pathway has been recently identified to play a crucial role in the progress of human gastric cancer. In this study, we show that mefloquine, a FDA-approved anti-malarial drug, effectively targets human gastric cancer cells. Mefloquine potently inhibits proliferation and induces apoptosis of a panel of human gastric cancer cell lines, with EC{sub 50} ∼0.5–0.7 μM. In two independent gastric cancer xenograft mouse models, mefloquine significantly inhibits growth of both tumors. The combination of mefloquine with paclitaxel enhances the activity of either drug alone in in vitro and in vivo. In addition, mefloquine potently decreased phosphorylation of PI3K, Akt, mTOR and rS6. Overexpression of constitutively active Akt significantly restored mefloquine-mediated inhibition of mTOR phosphorylation and growth, and induction of apoptosis, suggesting that mefloquine acts on gastric cancer cells via suppressing PI3K/Akt/mTOR pathway. We further show that mefloquine-mediated inhibition of Akt/mTOR singaling is phosphatase-dependent as pretreatment with calyculin A does-dependently reversed mefloquine-mediated inhibition of Akt/mTOR phosphorylation. Since mefloquine is already available for clinic use, these results suggest that it is a useful addition to the treatment armamentarium for gastric cancer. - Highlights: • Mefloquine targets a panel of gastric cancer cell lines in vitro and in vivo. • Combination of mefloquine and paclitaxel is synergistic. • Mefloquine acts on gastric cancer via inhibition of PI3K/Akt/mTOR pathway. • Mefloquine can be repurposed for gastric cancer treatment.

  19. Inositol hexaphosphate suppresses growth and induces apoptosis in prostate carcinoma cells in culture and nude mouse xenograft: PI3K-Akt pathway as potential target.

    Science.gov (United States)

    Gu, Mallikarjuna; Roy, Srirupa; Raina, Komal; Agarwal, Chapla; Agarwal, Rajesh

    2009-12-15

    Constitutive activation of phosphoinositide 3-kinase (PI3K)-Akt pathway transmits growth-regulatory signals that play a central role in promoting survival, proliferation, and angiogenesis in human prostate cancer cells. Here, we assessed the efficacy of inositol hexaphosphate (IP6) against invasive human prostate cancer PC-3 and C4-2B cells and regulation of PI3K-Akt pathway. IP6 treatment of cells suppressed proliferation, induced apoptosis along with caspase-3 and poly(ADP-ribose) polymerase (PARP) cleavage, and inhibited constitutive activation of Akt and its upstream regulators PI3K, phosphoinositide-dependent kinase-1 and integrin-linked kinase-1 (ILK1). Downstream of Akt, IP6 inhibited the phosphorylation of glycogen synthase kinase-3alpha/beta at Ser(21/9) and consequently reduced cyclin D1 expression. Efficacy studies employing PC-3 tumor xenograft growth in nude mice showed that 2% (w/v) IP6 feeding in drinking water inhibits tumor growth and weight by 52% to 59% (P IP6 significantly reduces the expression of molecules associated with cell survival/proliferation (ILK1, phosphorylated Akt, cyclin D1, and proliferating cell nuclear antigen) and angiogenesis (platelet endothelial cell adhesion molecule-1 or CD31, vascular endothelial growth factor, endothelial nitric oxide synthase, and hypoxia-inducible factor-1alpha) together with an increase in apoptotic markers (cleaved caspase-3 and PARP). These findings suggest that, by targeting the PI3K-ILK1-Akt pathway, IP6 suppresses cell survival, proliferation, and angiogenesis but induces death in prostate cancer cells, which might have translational potential in preventing and controlling the growth of advanced and aggressive prostate cancer for which conventional chemotherapy is not effective.

  20. Didymin Alleviates Hepatic Fibrosis Through Inhibiting ERK and PI3K/Akt Pathways via Regulation of Raf Kinase Inhibitor Protein

    Directory of Open Access Journals (Sweden)

    Xing Lin

    2016-12-01

    Full Text Available Background: Didymin has been reported to have anti-cancer potential. However, the effect of didymin on liver fibrosis remains illdefined. Methods: Hepatic fibrosis was induced by CCl4 in rats. The effects of didymin on liver pathology and collagen accumulation were observed by hematoxylin-eosin and Masson's trichrome staining, respectively. Serum transaminases activities and collagen-related indicators levels were determined by commercially available kits. Moreover, the effects of didymin on hepatic stellate cell apoptosis and cell cycle were analyzed by flow cytometry. Mitochondrial membrane potential was detected by using rhodamine-123 dye. The expression of Raf kinase inhibitor protein (RKIP and the phosphorylation of the ERK/MAPK and PI3K/Akt pathways were assessed by Western blot. Results: Didymin significantly ameliorated chronic liver injury and collagen deposition. It strongly inhibited hepatic stellate cells proliferation, induced apoptosis and caused cell cycle arrest in G2/M phase. Moreover, didymin notably attenuated mitochondrial membrane potential, accompanied by release of cytochrome C. Didymin significantly inhibited the ERK/MAPK and PI3K/Akt pathways. The effects of didymin on the collagen accumulation in rats and on the biological behaviors of hepatic stellate cells were largely abolished by the specific RKIP inhibitor locostatin. Conclusion: Didymin alleviates hepatic fibrosis by inhibiting ERK/MAPK and PI3K/Akt pathways via regulation of RKIP expression.

  1. PI3K/mTOR/S6K signaling pathway – new players and new functional links

    Directory of Open Access Journals (Sweden)

    Filonenko V. V.

    2013-05-01

    Full Text Available This review summarizes experimental data related to the studies of PI3K/mTOR/S6K signaling conducted at the department of cell signaling. Analysis of novel S6Ks protein-protein interactions provided valuable information for understanding molecular mechanisms of regulation of S6Ks functional activity and subcellular localization mediated by PKC, CK2 and ROC1 ubiquitin ligase. We discuss the identification and functional analysis of novel isoform of ribosomal protein S6 kinase – S6K2 and of mTOR kinase – mTOR, as well as their oncogenic properties. Identification of CoA synthase responsible for last two steps in CoA biosynthesis and characterization of its interactions with S6K1 and other signaling molecules uncovere a potential link between mTOR/S6K signaling pathway and energy metabolism through regulation of CoA biosynthesis. The data concerning new molecular mechanisms of CoA synthase regulation are presented.

  2. Induction of Haemeoxygenase-1 Directly Improves Endothelial Function in Isolated Aortas from Obese Rats through the Ampk-Pi3k/Akt-Enos Pathway

    Directory of Open Access Journals (Sweden)

    Fang Han

    2015-07-01

    Full Text Available Background: Induction of haemeoxygenase-1 (HO-1 increases adiponectin secretion by remodeling adipose tissue in obesity. The objective of our study is to explore whether HO-1 induction directly improves endothelial function independent of adiponectin changes in obese rats. Methods: Rats were divided into control and obesity groups. Aortic endothelial function was determined by measuring endothelium-dependent vasodilatation (EDV. Vascular segments of the obese rats were incubated in an organ bath in the presence or absence of cobalt protoporphyrin (CoPP or CoPP plus stannous protoporphyrin. Nitric oxide (NO production, superoxide anion production and NF-κB p65 expression in the aorta were determined. The expression of AMP-activated kinase (AMPK, Akt and endothelial nitric oxide synthase (eNOS in endothelial cells was determined by western blotting. The aortic rings from the obese rats were then incubated with CoPP in the presence of specific inhibitors of AMPK, phosphatidylinositol 3-kinase (PI3K or eNOS. Results: Acetylcholine-induced EDV was significantly attenuated in the obese rats, compared with the NC group (p p in vitro in the presence of inhibitors of AMPK, PI3K or eNOS. HO-1 induction with CoPP significantly increased the activation of the AMPK-PI3K/Akt-eNOS pathway and NO production in parallel with reduced superoxide anion production and NF-κB p65 expression in obese rats. Conclusions: HO-1 induction with CoPP directly improved endothelial function in obese rats independent of adiponectin changes. The mechanism of this protective effect is related to increasing NO production by activation of the AMPK-PI3K/Akt-eNOS signaling pathway.

  3. Kushenin induces the apoptosis of HCV-infected cells by blocking the PI3K-Akt-mTOR pathway via inhibiting NS5A.

    Science.gov (United States)

    Zhou, Yi; Chen, Na; Liu, Xiaojing; Lin, Shumei; Luo, Wenjuan; Liu, Min

    2016-07-01

    With the increased burden induced by HCV, there is an urgent need to develop better-tolerated agents with good safety. In this study, we evaluated the anti-HCV capability of kushenin, as well as the possible mechanism to Huh7.5-HCV cells. The results demonstrated that kushenin significantly inhibited the HCV-RNA level. Similarly, the expression of HCV-specific protein NS5A was also decreased. Molecular docking results displayed that kushenin bonded well to the active pockets of HCV NS5A, further confirming the effects of kushenin on HCV replication. Coimmunoprecipitation assay determined that kushenin suppressed the interaction between PI3K and NS5A in HCV-replicon cells. Furthermore, kushenin exerted an obviously induced function on HCV-replicon cells apoptosis by inhibiting PI3K-Akt-mTOR pathway, which could be ameliorated by the specific activator IGF-1 addition. Taken together, kushenin possesses the ability to inhibit HCV replication, and contributes to the increased apoptosis of HCV-infected cells by blocking the PI3K-Akt-mTOR pathway via inhibiting NS5A. Our results provide important evidence for a better understanding of the pathogenesis of HCV infection, and suggest that kushenin has the potential to treat HCV disease.

  4. Mefloquine effectively targets gastric cancer cells through phosphatase-dependent inhibition of PI3K/Akt/mTOR signaling pathway.

    Science.gov (United States)

    Liu, Yanwei; Chen, Sen; Xue, Rui; Zhao, Juan; Di, Maojun

    2016-02-05

    Deregulation of PI3K/Akt/mTOR pathway has been recently identified to play a crucial role in the progress of human gastric cancer. In this study, we show that mefloquine, a FDA-approved anti-malarial drug, effectively targets human gastric cancer cells. Mefloquine potently inhibits proliferation and induces apoptosis of a panel of human gastric cancer cell lines, with EC50 ∼ 0.5-0.7 μM. In two independent gastric cancer xenograft mouse models, mefloquine significantly inhibits growth of both tumors. The combination of mefloquine with paclitaxel enhances the activity of either drug alone in in vitro and in vivo. In addition, mefloquine potently decreased phosphorylation of PI3K, Akt, mTOR and rS6. Overexpression of constitutively active Akt significantly restored mefloquine-mediated inhibition of mTOR phosphorylation and growth, and induction of apoptosis, suggesting that mefloquine acts on gastric cancer cells via suppressing PI3K/Akt/mTOR pathway. We further show that mefloquine-mediated inhibition of Akt/mTOR singaling is phosphatase-dependent as pretreatment with calyculin A does-dependently reversed mefloquine-mediated inhibition of Akt/mTOR phosphorylation. Since mefloquine is already available for clinic use, these results suggest that it is a useful addition to the treatment armamentarium for gastric cancer.

  5. The PI3K/Akt pathway mediates the protection of SO2 preconditioning against myocardial ischemia/reperfusion injury in rats

    Institute of Scientific and Technical Information of China (English)

    Man-man ZHAO; Jin-yan YANG; Xin-bao WANG; Chao-shu TANG; Jun-bao DU; Hong-fang JIN

    2013-01-01

    Aim:To explore the mechanisms underlying the protection by SO2 preconditioning against rat myocardial ischemia/reperfusion (I/R)injury.Methods:Male Wistar rats underwent 30-min left coronary artery ligation followed by 120-min reperfusion.An S02 donor (1 μmol/kg)was intravenously injected 10 min before the ischemia,while LY294002 (0.3 mg/kg) was intravenously injected 30 min before the ischemia.Plasma activities of LDH and CK were measured with an automatic enzyme analyzer.Myocardial infarct size was detected using Evans-TTC method.The activities of caspase-3 and-9 in myocardium were assayed using a commercial kit,and the levels of p-Akt,Akt,P13K and p-P13K were examined with Western blotting.Results:Pretreatment with SO2 significantly reduced the myocardial infarct size and plasma LDH and CK activities,as well as myocardial caspase-3 and-9 activities in the rats.Furthermore,the pretreatment significantly increased the expression levels of myocardial p-Akt and p-PI3K p85.Administration of the PI3K inhibitor LY294002 blocked all the effects induced by SO2 pretreatment.Conclusion:The results suggest that the PI3K/Akt pathway mediates the protective effects of SO2 preconditioning against myocardial I/R injury in rats.

  6. Vanadate proliferative and anti-mineralogenic effects are mediated by MAPK and PI-3K/Ras/Erk pathways in a fish chondrocyte cell line.

    Science.gov (United States)

    Tiago, Daniel M; Cancela, M Leonor; Aureliano, Manuel; Laizé, Vincent

    2008-04-16

    We recently reported proliferative and anti-mineralogenic effects of vanadate on fish chondrocytes and here we investigate the signalling pathways associated with these effects. Our data show that vanadate stimulates chondrocyte proliferation through the MAPK pathway, using signalling mechanisms similar to those used by IGF-1, while it inhibits chondrocyte differentiation/mineralization through a putative PI-3K/Ras/Erk signalling, a pathway shared with insulin. Our data also suggest that vanadate impairs ECM mineralization not only by interfering with regulatory pathways but also by inhibiting enzymatic activity of ALP. Finally, this work provides additional evidence for the conservation, throughout evolution, of mechanisms regulating chondrocyte proliferation and differentiation.

  7. Cytoglobin inhibits migration through PI3K/AKT/mTOR pathway in fibroblast cells.

    Science.gov (United States)

    Demirci, Selami; Doğan, Ayşegül; Apdik, Hüseyin; Tuysuz, Emre Can; Gulluoglu, Sukru; Bayrak, Omer Faruk; Şahin, Fikrettin

    2017-06-15

    Cell proliferation and migration are crucial in many physiological processes including development, cancer, tissue repair, and wound healing. Cell migration is regulated by several signaling molecules. Identification of genes related to cell migration is required to understand molecular mechanism of non-healing chronic wounds which is a major concern in clinics. In the current study, the role of cytoglobin (CYGB) gene in fıbroblast cell migration and proliferation was described. L929 mouse fibroblast cells were transduced with lentiviral particles for CYGB and GFP, and analyzed for cell proliferation and migration ability. Fibroblast cells overexpressing CYGB displayed decreased cell proliferation, colony formation capacity, and cell migration. Phosphorylation levels of mTOR and two downstream effectors S6 and 4E-BP1 which take part in PI3K/AKT/mTOR signaling declined in CYGB-overexpressing cells. Microarray analysis indicated that CYGB overexpression leads to downregulation of cell proliferation, migration, and tumor growth associated genes in L929 cell line. This study demonstrated the role of CYGB in fibroblast cell motility and proliferation. CYGB could be a promising candidate for further studies as a potential target for diseases related to cell migration such as cancer and chronic wound treatment.

  8. The Bmx tyrosine kinase is activated by IL-3 and G-CSF in a PI-3K dependent manner.

    Science.gov (United States)

    Ekman, N; Arighi, E; Rajantie, I; Saharinen, P; Ristimäki, A; Silvennoinen, O; Alitalo, K

    2000-08-24

    Cytoplasmic protein tyrosine kinases play crucial roles in signaling via a variety of cell surface receptors. The Bmx tyrosine kinase, a member of the Tec family, is expressed in hematopoietic cells of the granulocytic and monocytic lineages. Here we show that Bmx is catalytically activated by interleukin-3 (IL-3) and granulocyte-colony stimulating factor (G-CSF) receptors. Activation of Bmx required phosphatidylinositol 3-kinase (PI-3K) as demonstrated by the ability of PI-3K inhibitors to block the activation signal. A green fluorescent protein (GFP) tagged Bmx was translocated to cellular membranes upon co-expression of a constitutively active form of PI-3K, further indicating a role for PI-3K in signaling upstream of Bmx. The expression of wild type Bmx in 32D myeloid progenitor cells resulted in apoptosis in the presence of G-CSF, while cells expressing a kinase dead mutant of Bmx differentiated into mature granulocytes. However, Bmx did not modulate IL-3-dependent proliferation of the cells. These results demonstrate distinct effects of Bmx in cytokine induced proliferation and differentiation of myeloid cells, and suggest that the stage specific expression of Bmx is critical for the differentiation of myeloid cells. Oncogene (2000) 19, 4151 - 4158

  9. The PI3K/Akt pathway is involved in procyanidin-mediated suppression of human colorectal cancer cell growth.

    Science.gov (United States)

    Choy, Ying Yng; Fraga, Magdalena; Mackenzie, Gerardo G; Waterhouse, Andrew L; Cremonini, Eleonora; Oteiza, Patricia I

    2016-12-01

    Colorectal cancer (CRC) has the third highest incidence worldwide. Epidemiological studies showed that the consumption of fruit and vegetables containing procyanidins (PCA), polymers of flavan-3-ols, is associated with lower CRC risk. However, the molecular mechanisms supporting this positive association are unclear. This study investigated the capacity of PCA with different degrees of polymerization to reduce CRC cell growth, characterizing the underlying mechanisms. Compared to the monomer ((-)-epicatechin) and the trimer, the hexamer (Hex) was the most active at reducing CRC cell viability. Hex caused a concentration- (2.5-50 μM) and time- (24-72 h) dependent decrease in the viability of six human CRC cell lines in culture. Hex caused CRC apoptotic Caco-2 cell death within 24 h, as evidenced by caspase 3 and caspase 9 activation, DNA fragmentation, and changes in nuclear morphology/staining. Hex-induced apoptosis occurs through the mitochondrial pathway, as evidenced by an increased Bad mitochondrial translocation, and cytochrome c release from the mitochondria to the cytosol. Hex also arrested the Caco-2 cell cycle at G2 /M phase and upregulated genes involved in autophagy. Mechanistically, in Caco-2 cells Hex inhibited the PI3K/Akt signaling pathway, causing the downstream downregulation of proteins involved in the regulation of cell survival (Bad, GSK-3β). Accordingly, the Akt inhibitor MKK-2206 decreased Bad and GSK-3β phosphorylation. MKK-2206 decreased cell growth, having an additive effect with Hex. In conclusion, our results show that large PCA can inhibit CRC cell growth via the Akt kinase pathway, demonstrating a mechanism to explain the epidemiological evidence linking PCA-rich diets with lower CRC risk. © 2016 Wiley Periodicals, Inc.

  10. Both mitogen-activated protein kinase (MAPK)/extracellular-signal-regulated kinases (ERK) 1/2 and phosphatidylinositide-3-OH kinase (PI3K)/Akt pathways regulate activation of E-twenty-six (ETS)-like transcription factor 1 (Elk-1) in U138 glioblastoma cells.

    Science.gov (United States)

    Mut, Melike; Lule, Sevda; Demir, Ozlem; Kurnaz, Isil Aksan; Vural, Imran

    2012-02-01

    Epidermal growth factor (EGF) and its receptor (EGFR) have been shown to play a significant role in the pathogenesis of glioblastoma. In our study, the EGFR was stimulated with EGF in human U138 glioblastoma cells. We show that the activated mitogen-activated protein kinase (MAPK)/extracellular-signal-regulated kinases (ERK) 1/2 pathway phosphorylated the E twenty-six (ETS)-like transcription factor 1 (Elk-1) mainly at serine 383 residue. Mitogen-activated protein kinase kinase (MEK) 1/2 inhibitor, UO126 and ERK inhibitor II, FR180204 blocked the Elk-1 phosphorylation and activation. The phosphatidylinositide-3-OH kinase (PI3K)/Akt pathway was also involved in the Elk-1 activation. Activation of the Elk-1 led to an increased survival and a proliferative response with the EGF stimulation in the U138 glioblastoma cells. Knocking-down the Elk-1 using an RNA interference technique caused a decrease in survival of the unstimulated U138 glioblastoma cells and also decreased the proliferative response to the EGF stimulation. The Elk-1 transcription factor was important for the survival and proliferation of U138 glioblastoma cells upon the stimulation of EGFR with EGF. The MAPK/ERK1/2 and PI3K/Akt pathways regulated this response via activation of the Elk-1 transcription factor. The Elk-1 may be one of the convergence points for pathways located downstream of EGFR in glioblastoma cells. Utilization of the Elk-1 as a therapeutic target may lead to a novel strategy in treatment of glioblastoma.

  11. Retraction: Genistein protects genioglossus myocyte against hypoxia-induced injury through PI3K-Akt and ERK MAPK pathways.

    Science.gov (United States)

    2012-05-01

    RETRACTION: The following article from Journal of Cellular Biochemistry, Genistein protects genioglossus myocyte against hypoxia-induced injury through PI3K-Akt and ERK MAPK pathways by Wanghui Ding and Yuehua Liu, posted online on May 19, 2011 in Wiley Online Library (onlinelibrary.wiley.com), has been retracted by agreement between the authors, the journal Editor in Chief, Dr. Gary S. Stein and Wiley-Liss, Inc. The retraction has been made as authorization to publish was not granted by one of the funding bodies.

  12. Inhibiting PI3K/Akt Pathway Increases DNA Damage of Cervical Carcinoma HeLa Cells by Drug Radiosensitization

    Institute of Scientific and Technical Information of China (English)

    夏曙; 于世英; 付强; 刘飞; 郑微; 付秀根; 赵茵

    2010-01-01

    This study examined the role of PI3K/Akt pathway in radiosensitization of DNA damage of cervical carcinoma cells.The 50% inhibition concentration(IC50) of cisplatin and docetaxel in HeLa cells was detected by Mono-nuclear cell direct cytotoxicity assay(MTT) in vitro.HeLa cells were treated by cisplatin/docetaxel of 10 percent of IC20 alone or combined with LY294002 for 24 h,and then radiated by different doses of X-ray.The cell survival ratio was obtained by means of clone formation.One-hit multi-target mod...

  13. Salvianolic Acid B Prevents Iodinated Contrast Media-Induced Acute Renal Injury in Rats via the PI3K/Akt/Nrf2 Pathway.

    Science.gov (United States)

    Tongqiang, Liu; Shaopeng, Liu; Xiaofang, Yu; Nana, Song; Xialian, Xu; Jiachang, Hu; Ting, Zhang; Xiaoqiang, Ding

    2016-01-01

    Contrast-induced acute renal injury (CI-AKI) has become a common cause of hospital-acquired renal failure. However, the development of prophylaxis strategies and approved therapies for CI-AKI is limited. Salvianolic acid B (SB) can treat cardiovascular-related diseases. The aim of the present study was to assess the effect of SB on prevention of CI-AKI and explore its underlying mechanisms. We examined its effectiveness of preventing renal injury in a novel CI-AKI rat model. Compared with saline, intravenous SB pretreatment significantly attenuated elevations in serum creatinine and the histological changes of renal tubular injuries, reduced the number of apoptosis-positive tubular cells, activated Nrf2, and lowered the levels of renal oxidative stress induced by iodinated contrast media. The above renoprotection of SB was abolished by the PI3K inhibitor (wortmannin). In HK-2 cells, SB activated Nrf2 and decreased the levels of oxidative stress induced by hydrogen peroxide and subsequently improved cell viability. The above cytoprotection of SB was blocked by the PI3K inhibitor (wortmannin) or siNrf2. Thus, our results demonstrate that, due to its antioxidant properties, SB has the potential to effectively prevent CI-AKI via the PI3K/Akt/Nrf2 pathway.

  14. Salvianolic Acid B Prevents Iodinated Contrast Media-Induced Acute Renal Injury in Rats via the PI3K/Akt/Nrf2 Pathway

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    Liu Tongqiang

    2016-01-01

    Full Text Available Contrast-induced acute renal injury (CI-AKI has become a common cause of hospital-acquired renal failure. However, the development of prophylaxis strategies and approved therapies for CI-AKI is limited. Salvianolic acid B (SB can treat cardiovascular-related diseases. The aim of the present study was to assess the effect of SB on prevention of CI-AKI and explore its underlying mechanisms. We examined its effectiveness of preventing renal injury in a novel CI-AKI rat model. Compared with saline, intravenous SB pretreatment significantly attenuated elevations in serum creatinine and the histological changes of renal tubular injuries, reduced the number of apoptosis-positive tubular cells, activated Nrf2, and lowered the levels of renal oxidative stress induced by iodinated contrast media. The above renoprotection of SB was abolished by the PI3K inhibitor (wortmannin. In HK-2 cells, SB activated Nrf2 and decreased the levels of oxidative stress induced by hydrogen peroxide and subsequently improved cell viability. The above cytoprotection of SB was blocked by the PI3K inhibitor (wortmannin or siNrf2. Thus, our results demonstrate that, due to its antioxidant properties, SB has the potential to effectively prevent CI-AKI via the PI3K/Akt/Nrf2 pathway.

  15. Isoorientin induces apoptosis through mitochondrial dysfunction and inhibition of PI3K/Akt signaling pathway in HepG2 cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Li; Wang, Jing; Xiao, Haifang; Xiao, Chunxia; Wang, Yutang; Liu, Xuebo, E-mail: xueboliu@yahoo.com.cn

    2012-11-15

    Isoorientin (ISO) is a flavonoid compound that can be extracted from several plant species, such as Phyllostachys pubescens, Patrinia, and Drosophyllum lusitanicum; however, its biological activity remains poorly understood. The present study investigated the effects and putative mechanism of apoptosis induced by ISO in human hepatoblastoma cancer (HepG2) cells. The results showed that ISO induced cell death in a dose-dependent manner in HepG2 cells, but no toxicity in human liver cells (HL-7702) and buffalo rat liver cells (BRL-3A) treated with ISO at the indicated concentrations. ISO-induced cell death included apoptosis which characterized by the appearance of nuclear shrinkage, the cleavage of poly (ADP-ribose) polymerase (PARP) and DNA fragmentation. ISO significantly (p < 0.01) increased the Bax/Bcl-2 ratio, disrupted the mitochondrial membrane potential (MMP), increased the release of cytochrome c, activated caspase-3, and enhanced intracellular levels of reactive oxygen species (ROS) and nitric oxide (NO). In addition, ISO effectively inhibited the phosphorylation of Akt and increased FoxO4 expression. The PI3K/Akt inhibitor LY294002 enhanced the apoptosis-inducing effect of ISO. However, LY294002 markedly quenched ROS and NO generation and diminished the protein expression of heme peroxidase enzyme (HO-1) and inducible nitric oxide synthase (iNOS). Furthermore, the addition of a ROS inhibitor (N-acetyl cysteine, NAC) or iNOS inhibitor (N-[3-(aminomethyl) benzyl] acetamidine, dihydrochloride, 1400W) significantly diminished the apoptosis induced by ISO and also blocked the phosphorylation of Akt. These results demonstrated for the first time that ISO induces apoptosis in HepG2 cells and indicate that this apoptosis might be mediated through mitochondrial dysfunction and PI3K/Akt signaling pathway, and has no toxicity in normal liver cells, suggesting that ISO may have good potential as a therapeutic and chemopreventive agent for liver cancer. Highlights:

  16. PI3K/Akt signal pathway involved in the cognitive impairment caused by chronic cerebral hypoperfusion in rats.

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    Yi Shu

    Full Text Available Chronic cerebral hypoperfusion (CCH is a common pathophysiological state that usually occurs in conditions such as vascular dementia and Alzheimer's disease, both of which are characterized by cognitive impairment. In previous studies we found that learning capacity and memory were gradually impaired with CCH, which altered the expression of synaptophysin, microtubule associated protein-2, growth associated protein-43, brain-derived neurotrophic factor, nerve growth factor, N-methyl-D-aspartate receptor subunit 1, cAMP response element-binding protein and tau hyperphosphorylation in the hippocampus. However, the molecular basis of cognitive impairment in CCH remains obscure. Here we explore the hypothesis that the phosphoinositide 3-kinase (PI3K/protein kinase B (Akt signal pathway is involved in this type of cognitive impairment. In order to determine if the expression of PI3K, Akt and phosphorylated Akt (p-Akt proteins are altered at different stages of CCH with differing levels of cognitive impairment. we performed permanent, bilateral occlusion of the common carotid arteries (2-VO to induce CCH. Adult male SD rats were randomly divided into sham-operated group, 2-VO 1 week group, 2-VO 4 weeks group and 2-VO 8 weeks group. Behavior tests were utilized to assess cognitive abilities, while western blots were utilized to evaluate protein expression. Rats in the 2-VO groups spent less time exploring novel objects than those in the sham-operated group, and the discrimination ratio of the 2-VO 8 weeks group and the sham-operated group were higher than chance (0.50. Escape latencies in the Morris water maze task in the 2-VO 1 week group were longer than those in the sham-operated group on day 4 and day 5, while escape latencies in the 2-VO 4 weeks group were longer than those in the sham-operated group from day 3 to day 5. Escape latencies in 2-VO 8 weeks group were longer than those in the sham-operated group from day 2 to day 5. NE (northeast

  17. Nontranscriptional activation of PI3K/Akt signaling mediates hypotensive effect following activation of estrogen receptor β in the rostral ventrolateral medulla of rats

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    Wu Kay LH

    2012-08-01

    Full Text Available Abstract Background Estrogen acts on the rostral ventrolateral medulla (RVLM, where sympathetic premotor neurons are located, to elicit vasodepressor effects via an estrogen receptor (ERβ-dependent mechanism. We investigated in the present study nontranscriptional mechanism on cardiovascular effects following activation of ERβ in the RVLM, and delineated the involvement of phosphatidylinositol 3-kinase (PI3K/serine/threonine kinase (Akt signaling pathway in the effects. Methods In male Sprague–Dawley rats maintained under propofol anesthesia, changes in arterial pressure, heart rate and sympathetic neurogenic vasomotor tone were examined after microinjection bilaterally into RVLM of 17β-estradiol (E2β or a selective ERα or ERβ agonist. Involvement of ER subtypes and PI3K/Akt signaling pathway in the induced cardiovascular effects were studied using pharmacological tools of antagonists or inhibitors, gene manipulation with antisense oligonucleotide (ASON or adenovirus-mediated gene transfection. Results Similar to E2β (1 pmol, microinjection of ERβ agonist, diarylpropionitrile (DPN, 1, 2 or 5 pmol, into bilateral RVLM evoked dose-dependent hypotension and reduction in sympathetic neurogenic vasomotor tone. These vasodepressive effects of DPN (2 pmol were inhibited by ERβ antagonist, R,R-tetrahydrochrysene (50 pmol, ASON against ERβ mRNA (250 pmol, PI3K inhibitor LY294002 (5 pmol, or Akt inhibitor (250 pmol, but not by ERα inhibitor, methyl-piperidino-pyrazole (1 nmol, or transcription inhibitor, actinomycin D (5 or 10 nmol. Gene transfer by microinjection into bilateral RVLM of adenovirus encoding phosphatase and tensin homologues deleted on chromosome 10 (5 × 108 pfu reversed the vasodepressive effects of DPN. Conclusions Our results indicate that vasodepressive effects following activation of ERβ in RVLM are mediated by nongenomic activation of PI3K/Akt signaling pathway. This study provides new insight in the

  18. Activation of PPAR-γ reduces HPA axis activity in diabetic rats by up-regulating PI3K expression.

    Science.gov (United States)

    Torres, Rafael Carvalho; Magalhães, Nathalia Santos; E Silva, Patrícia M R; Martins, Marco A; Carvalho, Vinicius F

    2016-10-01

    Increased hypothalamus-pituitary-adrenal axis (HPA) activity in diabetes is strongly associated with several morbidities noted in patients with the disease. We previously demonstrated that hyperactivity of HPA axis under diabetic conditions is associated with up-regulation of adrenocorticotrophic hormone (ACTH) receptors (MC2R) in adrenal and down-regulation of glucocorticoid receptors (GR and MR) in pituitary. This study investigates the role of peroxisome proliferator-activated receptor (PPAR)-γ in HPA axis hyperactivity in diabetic rats. Diabetes was induced by intravenous injection of alloxan into fasted rats. The PPAR-γ agonist rosiglitazone and/or PI3K inhibitor wortmannin were administered daily for 18 consecutive days, starting 3days after diabetes induction. Plasma ACTH and corticosterone were evaluated by radioimmunoassay, while intensities of MC2R, proopiomelanocortin (POMC), GR, MR, PI3K p110α and PPAR-γ were assessed using immunohistochemistry. Rosiglitazone treatment inhibited adrenal hypertrophy and hypercorticoidism observed in diabetic rats. Rosiglitazone also significantly reversed the diabetes-induced increase in the MC2R expression in adrenal cortex. We noted that rosiglitazone reduced the number of corticotroph cells and inhibited both anterior pituitary POMC expression and plasma ACTH levels. Furthermore, rosiglitazone treatment was unable to restore the reduced expression of GR and MR in the anterior pituitary of diabetic rats. Rosiglitazone increased the number of PPAR-γ(+) cells and expression of PI3K p110α in both anterior pituitary and adrenal cortex of diabetic rats. In addition, wortmannin blocked the ability of rosiglitazone to restore corticotroph cell numbers, adrenal hypertrophy and plasma corticosterone levels in diabetic rats. In conclusion, our findings revealed that rosiglitazone down-regulates HPA axis hyperactivity in diabetic rats via a mechanism dependent on PI3K activation in pituitary and adrenal glands.

  19. CXCL8 promotes the invasion of human osteosarcoma cells by regulation of PI3K/Akt signaling pathway.

    Science.gov (United States)

    Jiang, Hai; Wang, Xiaowei; Miao, Wusheng; Wang, Bing; Qiu, Yusheng

    2017-09-01

    Chemokine cysteine-X-cysteine motif ligand 8 (CXCL8) is up-regulated in many malignancies, indicating that CXCL8 takes part in tumor progression. However, the expression and function of CXCL8 in osteosarcoma remained not fully elucidated. In this study, expressions of 12 cytokines and chemokines were measured in the serum from 12 of normal controls (NCs) and 25 of osteosarcoma patients. The human osteosarcoma cell line MG-63 was stimulated by recombinant CXCL8 to further analyze invasion, proliferation, apoptosis, cell cycles, cytokine secretions, and signaling pathways. We found that serum concentrations of CXCL8 and vascular endothelial growth factor were elevated in osteosarcoma patients in comparison with those in NCs. CXCL8 stimulation led to enhancement of invasion and suppression of late stage apoptosis in MG-63 cells. Moreover, secretions of MMPs by MG-63 cells were also increased upon stimulation. However, early stage apoptosis, proliferation, and cell cycles were not affected by CXCL8 treatment. Furthermore, CXCL8 stimulation induced elevations of phosphorylated PI3K and Akt, but not PKC or FAK. In conclusion, our findings suggested that CXCL8 enhanced the invasion and suppressed late stage apoptosis of osteosarcoma cells probably via influencing PI3K/Akt signaling pathway and elevating the expression of MMPs. CXCL8 may promote disease progression of osteosarcoma as a protumorigenic molecule, and may be served as a new therapeutic target for osteosarcoma. © 2017 APMIS. Published by John Wiley & Sons Ltd.

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

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    Fumiko eObata

    2015-07-01

    Full Text Available 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.

  1. Matrine Suppresses Proliferation and Invasion of SGC7901 Cells through Inactivation of PI3K/Akt/uPA Pathway.

    Science.gov (United States)

    Peng, Xiaochun; Zhou, Dawei; Wang, Xianwang; Hu, Zhifan; Yan, Yan; Huang, Jiangrong

    2016-09-01

    This study was to examine the inhibitory effect of matrine on the proliferation and metastasis of gastric cancer cells, and to explore the possible mechanisms involved in these processes. MTT was used to evaluate the proliferation ability of SGC7901 cells. A two and three-dimensional cell migration assay were performed to determine the effect of matrine on the migration of SGC7901 cells. Then, the changes of the uPA protein and other possible signal molecules were detected by western blot. We found that the proliferation ability of SGC 7901 cells was suppressed by matrine (pmatrine when compared to the control in a two-dimensional cell migration assay. In addition, SGC7901cells treated with matrine (50μg/ml) migrated less than the control cells in a three-dimensional cell migration assay. At the meantime, the decreased uPA protein expression in SGC7901 cells treated with matrine was observed, and the PI3K/Akt pathway was inhibited. These results suggested that matrine can inhibit the proliferation and metastasis of gastric cancer cells through the PI3K/Akt/uPA pathway, indicating that matrine might be a potential molecular target for treatment of gastric carcinoma.

  2. Inhibitory effect of oxymatrine on hepatocyte apoptosis via TLR4/PI3K/Akt/GSK-3β signaling pathway.

    Science.gov (United States)

    Zhang, Xian; Jiang, Wei; Zhou, Ai-Ling; Zhao, Min; Jiang, Dao-Rong

    2017-06-07

    To evaluate the effect of oxymatrine (OMT) on hepatocyte apoptosis in rats with lipopolysaccharide (LPS)/D-galactosamine (D-GalN)-induced acute liver failure (ALF). LPS/D-GalN was used to establish a model of ALF in rats. To evaluate the effect of OMT, we assessed apoptosis by transmission electron microscopy, and the pathological changes in the liver by light microscopy with hematoxylin and eosin staining. An automated biochemical analyzer was used to measure serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Enzyme-linked immunosorbent assay was used to determine the levels of tumor necrosis factor (TNF)-α and interleukin (IL)-1β. Western blotting was used to detect protein levels in liver tissues. Streptavidin peroxidase immunohistochemistry was used to observe expression of Toll-like receptor (TLR)4, active caspase-3, Bax and Bcl-2. All rats in the normal control and OMT-pretreated groups survived. The mortality rate in the model group was 30%. OMT preconditioning down-regulated apoptosis of hepatocytes and ameliorated pathological changes in liver tissue. The levels of AST, ALT, TNF-α and IL-1β in the model group increased significantly, and were significantly reduced by OMT pretreatment. OMT pretreatment down-regulated expression of TLR4 and active caspase-3 and the Bax/Bcl-2 ratio, and up-regulated expression of P-Akt(Ser473) (Akt phosphorylated at serine 473) and P-GSK3β(Ser9) (glycogen synthase kinase 3β phosphorylated at serine 9) induced by LPS/D-GalN. OMT inhibits hepatocyte apoptosis by suppressing the TLR4/PI3K/Akt/GSK-3β signaling pathway, which suggests that OMT is an effective candidate for ameliorating acute liver failure.

  3. The naturally processed CD95L elicits a c-yes/calcium/PI3K-driven cell migration pathway.

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    Sébastien Tauzin

    2011-06-01

    Full Text Available Patients affected by chronic inflammatory disorders display high amounts of soluble CD95L. This homotrimeric ligand arises from the cleavage by metalloproteases of its membrane-bound counterpart, a strong apoptotic inducer. In contrast, the naturally processed CD95L is viewed as an apoptotic antagonist competing with its membrane counterpart for binding to CD95. Recent reports pinpointed that activation of CD95 may attract myeloid and tumoral cells, which display resistance to the CD95-mediated apoptotic signal. However, all these studies were performed using chimeric CD95Ls (oligomerized forms, which behave as the membrane-bound ligand and not as the naturally processed CD95L. Herein, we examine the biological effects of the metalloprotease-cleaved CD95L on CD95-sensitive activated T-lymphocytes. We demonstrate that cleaved CD95L (cl-CD95L, found increased in sera of systemic lupus erythematosus (SLE patients as compared to that of healthy individuals, promotes the formation of migrating pseudopods at the leading edge of which the death receptor CD95 is capped (confocal microscopy. Using different migration assays (wound healing/Boyden Chamber/endothelial transmigration, we uncover that cl-CD95L promotes cell migration through a c-yes/Ca²⁺/PI3K-driven signaling pathway, which relies on the formation of a CD95-containing complex designated the MISC for Motility-Inducing Signaling Complex. These findings revisit the role of the metalloprotease-cleaved CD95L and emphasize that the increase in cl-CD95L observed in patients affected by chronic inflammatory disorders may fuel the local or systemic tissue damage by promoting tissue-filtration of immune cells.

  4. Endothelium-Dependent Relaxation Effect of Apocynum venetum Leaf Extract via Src/PI3K/Akt Signalling Pathway

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    Yeh Siang Lau

    2015-06-01

    Full Text Available Botanical herbs are consumed globally not only as an essential diet but also as medicines or as functional/recreational food supplements. The extract of the Apocynum venetum leaves (AVLE, also known as Luobuma, exerts its antihypertensive effect via dilating the blood vessels in an endothelium- and concentration-dependent manner with optimal effect seen at as low as 10 µg/mL. A commercial Luoboma “antihypertensive tea” is available commercially in the western province of China. The present study seeks to investigate the underlying cellular mechanisms of the nitric oxide (NO-releasing property of AVLE in rat aortas and human umbilical vein endothelial cells (HUVECs. Endothelium-dependent relaxation induced by AVLE was assessed in organ chambers in the presence or absence of polyethyleneglycol catalase (PP2, 20 µM; inhibitor of Src kinase, wortmannin (30 nM and LY294002 (20 µM; PI3 (phosphatidylinositol3-Kinase inhibitor, NG-nitro-l-arginine (L-NAME, 100 µM; endothelial NO synthase inhibitor (eNOS and ODQ (1 µM; soluble guanylyl cyclase inhibitor. Total nitrite and nitrate (NOx level and protein expression of p-Akt and p-eNOS were measured. AVLE-induced endothelium-dependent relaxation was reduced by PP2, wortmannin and LY294002 and abolished by L-NAME and ODQ. AVLE significantly increased total NOx level in rat aortas and in HUVECs compared to control. It also instigated phosphorylation of Akt and eNOS in cultured HUVECs in a concentration-dependent manner and this was markedly suppressed by PP2, wortmannin and LY294002. AVLE also inhibited superoxide generated from both NADPH oxidase and xanthine/xanthine oxidase system. Taken together, AVLE causes endothelium-dependent NO mediated relaxations of rat aortas through Src/PI3K/Akt dependent NO signalling pathway and possesses superoxide scavenging activity.

  5. Mutation of genes of the PI3K/AKT pathway in breast cancer supports their potential importance as biomarker for breast cancer aggressiveness.

    Science.gov (United States)

    Tserga, Aggeliki; Chatziandreou, Ilenia; Michalopoulos, Nicolaos V; Patsouris, Efstratios; Saetta, Angelica A

    2016-07-01

    Deregulation of phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway is closely associated with cancer development and cancer progression. PIK3CA, AKT1, and PTEN are the fundamental molecules of the PI3K/AKT pathway with increased mutation rates in cancer cases leading to aberrant regulation of the pathway. Even though molecular alterations of the PI3K/AKT pathway have been studied in breast cancer, correlations between specific molecular alterations and clinicopathological features remain contradictory. In this study, we examined mutations of the PI3K/AKT pathway in 75 breast carcinomas using high-resolution melting analysis and pyrosequencing, in parallel with analysis of relative expression of PIK3CA and AKT2 genes. Mutations of PIK3CA were found in our cohort in 21 cases (28 %), 10 (13 %) in exon 9 and 11(15 %) in exon 20. Mutation frequency of AKT1 and PTEN genes was 4 and 3 %, respectively. Overall, alterations in the PI3K/AKT signaling cascade were detected in 35 % of the cases. Furthermore, comparison of 50 breast carcinomas with adjacent normal tissues showed elevated PIK3CA messenger RNA (mRNA) levels in 18 % of tumor cases and elevated AKT2 mRNA levels in 14 %. Our findings, along with those of previous studies, underline the importance of the PI3K/AKT pathway components as potential biomarkers for breast carcinogenesis.

  6. The PI3K/p-Akt signaling pathway participates in calcitriol ameliorating podocyte injury in DN rats.

    Science.gov (United States)

    Song, Zhixia; Guo, Yinfeng; Zhou, Min; Zhang, Xiaoliang

    2014-10-01

    The present study aimed to investigate the relationship between PI3K/p-Akt signaling pathway and podocyte impairment in DN rats as well as the protective effect of calcitriol. SD rats were randomly divided into four groups: normal control (NC), normal treated with calcitriol (NC+VD), diabetic nephropathy (DN) and DN treated with calcitriol (DN+VD); all VD rats were treated with 0.1 μg/kg/d calcitriol by gavage. DN model rats were established by intraperitoneal injections of streptozotocin (STZ). Rats were sacrificed after 18 weeks of treatments. In the present study, increased albuminuria was observed as early as 3 weeks of diabetes and continued to increase more than six-fold throughout the length of the study (18 weeks). Expectedly, animals receiving the treatment with calcitriol was protected from this increase, lower about one third. Meanwhile, the expression of podocyte specific markers, including nephrin and podocin, together with PI3K/p-Akt was significantly decreased in DN rats, whereas calcitriol reversed these above changes accompanied by elevated the expression levels of VDR. Additionally, a positive correlation was observed between the expression levels of nephrin and VDR (r = 0.776, P DN rats. The manipulation of calcitriol might act as a promising therapeutic intervention for diabetic nephropathy. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. The Gene Expression Status of the PI3K/AKT/mTOR Pathway in Gastric Cancer Tissues and Cell Lines.

    Science.gov (United States)

    Riquelme, Ismael; Tapia, Oscar; Espinoza, Jaime A; Leal, Pamela; Buchegger, Kurt; Sandoval, Alejandra; Bizama, Carolina; Araya, Juan Carlos; Peek, Richard M; Roa, Juan Carlos

    2016-10-01

    The PI3K/AKT/mTOR pathway plays a crucial role in the regulation of multiple cellular functions including cell growth, proliferation, metabolism and angiogenesis. Emerging evidence has shown that deregulation of this pathway has a role promoting gastric cancer (GC). The aim was to assess the expression of genes involved in this pathway by qPCR in 23 tumor and 23 non-tumor gastric mucosa samples from advanced GC patients, and in AGS, MKN28 and MKN45 gastric cancer cell lines. Results showed a slight overexpression of PIK3CA, PIK3CB, AKT1, MTOR, RPS6KB1, EIF4EBP1 and EIF4E genes, and a slightly decreased PTEN and TSC1 expression. In AGS, MKN28 and MKN45 cells a significant gene overexpression of PIK3CA, PIK3CB, AKT1, MTOR, RPS6KB1 and EIF4E, and a significant repression of PTEN gene expression were observed. Immunoblotting showed that PI3K-β, AKT, p-AKT, PTEN, mTOR, p-mTOR, P70S6K1, p-P70S6K1, 4E-BP1, p-4E-BP1, eIF4E and p-eIF4E proteins were present in cell lines at different levels, confirming activation of this pathway in vitro. This is the first time this extensive panel of 9 genes within PI3K/AKT/mTOR pathway has been studied in GC to clarify the biological role of this pathway in GC and develop new strategies for this malignancy.

  8. Isorhamnetin protects against cardiac hypertrophy through blocking PI3K-AKT pathway.

    Science.gov (United States)

    Gao, Lu; Yao, Rui; Liu, Yuzhou; Wang, Zheng; Huang, Zhen; Du, Binbin; Zhang, Dianhong; Wu, Leiming; Xiao, Lili; Zhang, Yanzhou

    2017-05-01

    Isorhamnetin, a flavonoid compound extracted from the Chinese herb Hippophae rhamnoides L., is well known for its anti-inflammatory, anti-oxidative, anti-adipogenic, anti-proliferative, and anti-tumor activities. However, the role of isorhamnetin in cardiac hypertrophy has not been reported. The aims of the present study were to find whether isorhamnetin could alleviate cardiac hypertrophy and to define the underlying molecular mechanisms. Here, we investigated the effects of isorhamnetin (100 mg/kg/day) on cardiac hypertrophy induced by aortic banding in mice. Cardiac hypertrophy was evaluated by echocardiographic, hemodynamic, pathological, and molecular analyses. Our data demonstrated that isorhamnetin could inhibit cardiac hypertrophy and fibrosis 8 weeks after aortic banding. The results further revealed that the effect of isorhamnetin on cardiac hypertrophy was mediated by blocking the activation of phosphatidylinositol 3-kinase-AKT signaling pathway. In vitro studies performed in neonatal rat cardiomyocytes confirmed that isorhamnetin could attenuate cardiomyocyte hypertrophy induced by angiotensin II, which was associated with phosphatidylinositol 3-kinase-AKT signaling pathway. In conclusion, these data indicate for the first time that isorhamnetin has protective potential for targeting cardiac hypertrophy by blocking the phosphatidylinositol 3-kinase-AKT signaling pathway. Thus, our study suggests that isorhamnetin may represent a potential therapeutic strategy for the treatment of cardiac hypertrophy and heart failure.

  9. Wortmannin potentiates roscovitine-induced growth inhibition in human solid tumor cells by repressing PI3K/Akt pathway.

    Science.gov (United States)

    Zhang, Feng; Zhang, Tao; Jiang, Tao; Zhang, Rong; Teng, Zeng-hui; Li, Chen; Gu, Zhong-Ping; Mei, Qibing

    2009-12-28

    Roscovitine has been reported to have anti-tumor effects in some cancer cell lines. The phosphatidylinositol-3-kinase (PI3K) signaling, which activates protein kinase B (PKB)/Akt, is known to mediate cell survival. The current study examined the role of wortmannin, a PI3K inhibitor, as a chemosensitizer for roscovitine and its proposed mechanism of action. The results showed that wortmannin significantly chemosensitized three human tumor cell lines (A549, HCT116 and HeLa cells). In A549 cells, wortmannin increased roscovitine-induced apoptosis in a dose-dependent manner, which was correlated with the inhibition of phosphorylated PKB/Akt level. Wortmannin enhanced the effects of roscovitine by causing pronounced reduction of mitochondrial transmembrane potential (MMP) and increases of cytochrome c release and active caspase-3, as well as enhanced activation of Bax and Bad, including Bax oligomerization and mitochondrial translocation of Bax and Bad. Taken together, these results provide evidence for the potential application of roscovitine/wormannin combination in clinical treatment for solid tumors.

  10. ALDH1B1 Is Crucial for Colon Tumorigenesis by Modulating Wnt/β-Catenin, Notch and PI3K/Akt Signaling Pathways.

    Directory of Open Access Journals (Sweden)

    Surendra Singh

    Full Text Available In the normal human colon, aldehyde dehydrogenase 1B1 (ALDH1B1 is expressed only at the crypt base, along with stem cells. It is also highly expressed in the human colonic adenocarcinomas. This pattern of expression corresponds closely to that observed for Wnt/β-catenin signaling activity. The present study examines the role of ALDH1B1 in colon tumorigenesis and signalling pathways mediating its effects. In a 3-dimensional spheroid growth model and a nude mouse xenograft tumor model, shRNA-induced suppression of ALDH1B1 expression decreased the number and size of spheroids formed in vitro and the size of xenograft tumors formed in vivo by SW 480 cells. Six binding elements for Wnt/β-catenin signalling transcription factor binding elements (T-cell factor/lymphoid enhancing factor were identified in the human ALDH1B1 gene promoter (3 kb but shown by dual luciferase reporter assay to not be necessary for ALDH1B1 mRNA expression in colon adenocarcinoma cell lines. We examined Wnt-reporter activity and protein/mRNA expression for Wnt, Notch and PI3K/Akt signaling pathways. Wnt/β-catenin, Notch and PI3K/Akt-signaling pathways were down-regulated in SW 480 cells in which ALDH1B1 expression had been suppressed. In summary, our data demonstrate that ALDH1B1 may promote colon cancer tumorigenesis by modulating the Wnt/β-catenin, Notch and PI3K/Akt signaling pathways. Selective targeting of ALDH1B1 may represent a novel means to prevent or treat colon cancer.

  11. Obesity enhances nongenomic estrogen receptor crosstalk with the PI3K/Akt and MAPK pathways to promote in vitro measures of breast cancer progression.

    Science.gov (United States)

    Bowers, Laura W; Cavazos, David A; Maximo, Ilane X F; Brenner, Andrew J; Hursting, Stephen D; deGraffenried, Linda A

    2013-01-01

    Epidemiological and clinical studies indicate that obesity is associated with a worse postmenopausal breast cancer prognosis and an increased risk of endocrine therapy resistance. However, the mechanisms mediating these effects remain poorly understood. Here we investigate the molecular pathways by which obesity-associated circulating factors in the blood enhance estrogen receptor alpha (ERα) positive breast cancer cell viability and growth. Blood serum was collected from postmenopausal breast cancer patients and pooled by body mass index (BMI) category (Control: 18.5 to 24.9 kg/m²; Obese: ≥30.0 kg/m²). The effects of patient sera on MCF-7 and T47D breast cancer cell viability and growth were examined by MTT and colony formation assays, respectively. Insulin-like growth factor receptor 1(IGF-1R), Akt, and ERK1/2 activation and genomic ERα activity were assessed to determine their possible contribution to obese patient sera-induced cell viability and growth. To further define the relative contribution of these signaling pathways, cells grown in patient sera were treated with various combinations of ERα, PI3K/Akt and MAPK targeted therapies. Comparisons between cells exposed to different experimental conditions were made using one-way analysis of variance (ANOVA) and Student's t test. Cells grown in media supplemented with obese patient sera displayed greater cell viability and growth as well as IGF-1R, Akt and ERK1/2 activation relative to control sera. Despite the lack of a significant difference in genomic ERα activity following growth in obese versus control patient sera, we observed a dramatic reduction in cell viability and growth after concurrent inhibition of the ERα and PI3K/Akt signaling pathways. Further, we demonstrated that ERα inhibition was sufficient to attenuate obese serum-induced Akt and ERK1/2 activation. Together, these data suggest that obesity promotes greater ERα positive breast cancer cell viability and growth through enhanced

  12. Apelin-13 upregulates Egr-1 expression in rat vascular smooth muscle cells through the PI3K/Akt and PKC signaling pathways

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Qi-Feng [Department of Cardiology, The First Affiliated Hospital of Liaoning Medical University, Jinzhou 121001 (China); Yu, Hong-Wei [Department of Cardiology, Jinzhou Central Hospital, Jinzhou 121001 (China); Sun, Li-Li [Department of Ophthalmology, The Third Affiliated Hospital of Liaoning Medical University, Jinzhou 121001 (China); You, Lu; Tao, Gui-Zhou [Department of Cardiology, The First Affiliated Hospital of Liaoning Medical University, Jinzhou 121001 (China); Qu, Bao-Ze, E-mail: qubaoze1971@hotmail.com [Department of Cardiology, The First Affiliated Hospital of Liaoning Medical University, Jinzhou 121001 (China)

    2015-12-25

    Previous studies have shown that Apelin-13 upregulates early growth response factor-1 (Egr-1) via the extracellular signal-regulated protein kinase (ERK) signaling pathway. Apelin-13 induces proliferation and migration of vascular smooth muscle cells (VSMCs) as well as the upregulation of osteopontin (OPN) via the upregulation of Egr-1. This study was designed to further explore the activity of Apelin-13 in VSMCs by investigating members of the mitogen-activated protein kinase (MAPK) family, in particular Jun kinase (JNK) and p38 mitogen-activated protein kinase (P38). We also examined whether the phosphatidylinositol 3 kinase (PI3K)/protein kinase B (Akt) and protein kinase C (PKC) signaling pathways were involved in the regulation of Egr-1 by Apelin-13. We treated rat aortic VSMCs with Apelin-13 and examined the expression of JNK, p-JNK, P38, and p-P38 to investigate whether Apelin-13-mediated increases in Egr-1 occurred through the JNK and P38 signaling pathways. We then pretreated VSMCs with the Gi protein inhibitor pertussis toxin (PTX) and the Gq inhibitor YM254890, added Apelin-13 and looked for changes in Egr-1 expression. Finally, we pretreated with the PI3K inhibitor LY294002 and the PKC inhibitor GF109203X, and treated with Apelin-13. Our results showed that JNK and P38 did not participate in Apelin-13-mediated increase in Egr-1. Instead, Apelin-13 upregulation of Egr-1 was mediated by a PTX-sensitive Gi protein. Apelin-13 did increase ERK phosphorylation through the PI3K/Akt and PKC signaling pathways, resulting in changes in Egr-1 expression. These data provide important targets for future studies to modulate vascular remodeling. - Highlights: • Apelin-13 mediates Egr-1 upregulation in vascular smooth muscle cells via ERK1/2. • The underlying mechanisms are unknown, but exclude Jnk or p38 pathway activation. • Apelin-13 binds to Gi, activating the PI3K/Akt and PKC signaling cascades. • Consequent ERK phosphorylation results in increased Egr-1

  13. TRPM7 channel regulates PDGF-BB-induced proliferation of hepatic stellate cells via PI3K and ERK pathways

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Ling, E-mail: fangling_1984@126.com; Zhan, Shuxiang; Huang, Cheng; Cheng, Xi; Lv, Xiongwen; Si, Hongfang; Li, Jun, E-mail: lj@ahmu.edu.cn

    2013-11-01

    TRPM7, a non-selective cation channel of the TRP channel superfamily, is implicated in diverse physiological and pathological processes including cell proliferation. Recently, TRPM7 has been reported in hepatic stellate cells (HSCs). Here, we investigated the contribution role of TRPM7 in activated HSC-T6 cell (a rat hepatic stellate cell line) proliferation. TRPM7 mRNA and protein were measured by RT-PCR and Western blot in rat model of liver fibrosis in vivo and PDGF-BB-activated HSC-T6 cells in vitro. Both mRNA and protein of TRPM7 were dramatically increased in CCl{sub 4}-treated rat livers. Stimulation of HSC-T6 cells with PDGF-BB resulted in a time-dependent increase of TRPM7 mRNA and protein. However, PDGF-BB-induced HSC-T6 cell proliferation was inhibited by non-specific TRPM7 blocker 2-aminoethoxydiphenyl borate (2-APB) or synthetic siRNA targeting TRPM7, and this was accompanied by downregulation of cell cycle proteins, cyclin D1, PCNA and CDK4. Blockade of TRPM7 channels also attenuated PDGF-BB induced expression of myofibroblast markers as measured by the induction of α-SMA and Col1α1. Furthermore, the phosphorylation of ERK and AKT, associated with cell proliferation, decreased in TRPM7 deficient HSC-T6 cells. These observations suggested that TRPM7 channels contribute to perpetuated fibroblast activation and proliferation of PDGF-BB induced HSC-T6 cells via the activation of ERK and PI3K pathways. Therefore, TRPM7 may constitute a useful target for the treatment of liver fibrosis. - Highlights: • Upregulation of TRPM7 mRNA and protein in the fibrotic livers from CCl{sub 4}-treated rats. • Increasing expression of TRPM7 mRNA and protein during HSC activation. • Blockade of TRPM7 inhibited the PDGF-BB induced proliferation of HSC-T6 cells. • Blockade of TRPM7 decreased α-SMA and Col1α1 expressions in activated HSC-T6 cells. • TRPM7 up-regulation contributes to the activation of ERK and AKT pathways.

  14. Twist promotes reprogramming of glucose metabolism in breast cancer cells through PI3K/AKT and p53 signaling pathways.

    Science.gov (United States)

    Yang, Li; Hou, Yixuan; Yuan, Jie; Tang, Shifu; Zhang, Hailong; Zhu, Qing; Du, Yan-e; Zhou, Mingli; Wen, Siyang; Xu, Liyun; Tang, Xi; Cui, Xiaojiang; Liu, Manran

    2015-09-22

    Twist, a key regulator of epithelial-mesenchymal transition (EMT), plays an important role in the development of a tumorigenic phenotype. Energy metabolism reprogramming (EMR), a newly discovered hallmark of cancer cells, potentiates cancer cell proliferation, survival, and invasion. Currently little is known about the effects of Twist on tumor EMR. In this study, we found that glucose consumption and lactate production were increased and mitochondrial mass was decreased in Twist-overexpressing MCF10A mammary epithelial cells compared with vector-expressing MCF10A cells. Moreover, these Twist-induced phenotypic changes were augmented by hypoxia. The expression of some glucose metabolism-related genes such as PKM2, LDHA, and G6PD was also found to be upregulated. Mechanistically, activated β1-integrin/FAK/PI3K/AKT/mTOR and suppressed P53 signaling were responsible for the observed EMR. Knockdown of Twist reversed the effects of Twist on EMR in Twist-overexpressing MCF10A cells and Twist-positive breast cancer cells. Furthermore, blockage of the β1-integrin/FAK/PI3K/AKT/mTOR pathway by siRNA or specific chemical inhibitors, or rescue of p53 activation can partially reverse the switch of glucose metabolism and inhibit the migration of Twist-overexpressing MCF10A cells and Twist-positive breast cancer cells. Thus, our data suggest that Twist promotes reprogramming of glucose metabolism in MCF10A-Twist cells and Twist-positive breast cancer cells via activation of the β1-integrin/FAK/PI3K/AKT/mTOR pathway and inhibition of the p53 pathway. Our study provides new insight into EMR.

  15. Salvianolic acid A reverses paclitaxel resistance in human breast cancer MCF-7 cells via targeting the expression of transgelin 2 and attenuating PI3 K/Akt pathway.

    Science.gov (United States)

    Cai, Jiangxia; Chen, Siying; Zhang, Weipeng; Zheng, Xiaowei; Hu, Sasa; Pang, Chengsen; Lu, Jun; Xing, Jianfeng; Dong, Yalin

    2014-10-15

    Chemotherapy resistance represents a major problem for the treatment of patients with breast cancer and greatly restricts the use of first-line chemotherapeutics paclitaxel. The purpose of this study was to investigate the role of transgelin 2 in human breast cancer paclitaxel resistance cell line (MCF-7/PTX) and the reversal mechanism of salvianolic acid A (SAA), a phenolic active compound extracted from Salvia miltiorrhiza. Western blotting and real-time quantitative polymerase chain reaction (qRT-PCR) indicated that transgelin 2 may mediate paclitaxel resistance by activating the phosphatidylinositol 3-kinase (PI3 K)/Akt signaling pathway to suppress MCF-7/PTX cells apoptosis. The reversal ability of SAA was confirmed by MTT assay and flow cytometry, with a superior 9.1-fold reversal index and enhancement of the apoptotic cytotoxicity induced by paclitaxel. In addition, SAA effectively prevented transgelin 2 and adenosine-triphosphate binding cassette transporter (ABC transporter) including P-glycoprotein (P-gp), multidrug resistance associated protein 1 (MRP1), and breast cancer resistance protein (BCRP) up-regulation and exhibited inhibitory effect on PI3 K/Akt signaling pathway in MCF-7/PTX cells. Taken together, SAA can reverse paclitaxel resistance through suppressing transgelin 2 expression by mechanisms involving attenuation of PI3 K/Akt pathway activation and ABC transporter up-regulation. These results not only provide insight into the potential application of SAA in reversing paclitaxel resistance, thus facilitating the sensitivity of breast cancer chemotherapy, but also highlight a potential role of transgelin 2 in the development of paclitaxel resistance in breast cancer.

  16. Camptothecin inhibits platelet-derived growth factor-BB-induced proliferation of rat aortic vascular smooth muscle cells through inhibition of PI3K/Akt signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    Park, Eun-Seok [Department of Applied Biochemistry, Division of Life Science, College of Health and Biomedical Science, Konkuk University, Chungju, Chungbuk (Korea, Republic of); Kang, Shin-il [College of Pharmacy Medical Research Center, Chungbuk National University, Cheongju (Korea, Republic of); Yoo, Kyu-dong [Hazardous Substances Analysis Division, Gwangju Regional Food and Drug Administration, Gwangju (Korea, Republic of); Lee, Mi-Yea [Department of Nursing Kyungbok University, Pocheon (Korea, Republic of); Yoo, Hwan-Soo; Hong, Jin-Tae [College of Pharmacy Medical Research Center, Chungbuk National University, Cheongju (Korea, Republic of); Shin, Hwa-Sup [Department of Applied Biochemistry, Division of Life Science, College of Health and Biomedical Science, Konkuk University, Chungju, Chungbuk (Korea, Republic of); Kim, Bokyung [Department of Physiology, Konkuk Medical School, Konkuk University, Chungju, Chungbuk (Korea, Republic of); Yun, Yeo-Pyo, E-mail: ypyun@chungbuk.ac.kr [College of Pharmacy Medical Research Center, Chungbuk National University, Cheongju (Korea, Republic of)

    2013-04-15

    The abnormal proliferation of vascular smooth muscle cells (VSMCs) in arterial wall is a major cause of vascular disorders such as atherosclerosis and restenosis after angioplasty. In this study, we investigated not only the inhibitory effects of camptothecin (CPT) on PDGF-BB-induced VSMC proliferation, but also its molecular mechanism of this inhibition. CPT significantly inhibited proliferation with IC50 value of 0.58 μM and the DNA synthesis of PDGF-BB-stimulated VSMCs in a dose-dependent manner (0.5–2 μM ) without any cytotoxicity. CPT induced the cell cycle arrest at G0/G1 phase. Also, CPT decreased the expressions of G0/G1-specific regulatory proteins including cyclin-dependent kinase (CDK)2, cyclin D1 and PCNA in PDGF-BB-stimulated VSMCs. Pre-incubation of VSMCs with CPT significantly inhibited PDGF-BB-induced Akt activation, whereas CPT did not affect PDGF-receptor beta phosphorylation, extracellular signal-regulated kinase (ERK) 1/2 phosphorylation and phospholipase C (PLC)-γ1 phosphorylation in PDGF-BB signaling pathway. Our data showed that CPT pre-treatment inhibited VSMC proliferation, and that the inhibitory effect of CPT was enhanced by LY294002, a PI3K inhibitor, on PDGF-BB-induced VSMC proliferation. In addition, inhibiting the PI3K/Akt pathway by LY294002 significantly enhanced the suppression of PCNA expression and Akt activation by CPT. These results suggest that the anti-proliferative activity of CPT is mediated in part by downregulating the PI3K/Akt signaling pathway. - Highlights: ► CPT inhibits proliferation of PDGF-BB-induced VSMC without cytotoxicity. ► CPT arrests the cell cycle in G0/G1 phase by downregulation of cyclin D1 and CDK2. ► CPT significantly attenuates Akt phosphorylation in PDGF-BB signaling pathway. ► LY294002 enhanced the inhibitory effect of CPT on VSMC proliferation. ► Thus, CPT is mediated by downregulating the PI3K/Akt signaling pathway.

  17. Synaptically Driven Phosphorylation of Ribosomal Protein S6 Is Differentially Regulated at Active Synapses versus Dendrites and Cell Bodies by MAPK and PI3K/mTOR Signaling Pathways

    Science.gov (United States)

    Pirbhoy, Patricia Salgado; Farris, Shannon; Steward, Oswald

    2017-01-01

    High-frequency stimulation of the medial perforant path triggers robust phosphorylation of ribosomal protein S6 (rpS6) in activated dendritic domains and granule cell bodies. Here we dissect the signaling pathways responsible for synaptically driven rpS6 phosphorylation in the dentate gyrus using pharmacological agents to inhibit PI3-kinase/mTOR…

  18. Survival advantages conferred to colon cancer cells by E-selectin-induced activation of the PI3K-NFκB survival axis downstream of Death receptor-3

    Directory of Open Access Journals (Sweden)

    Paquet Éric R

    2011-07-01

    Full Text Available Abstract Background Extravasation of circulating cancer cells is a key event of metastatic dissemination that is initiated by the adhesion of cancer cells to endothelial cells. It requires interactions between adhesion receptors on endothelial cells and their counter-receptors on cancer cells. Notably, E-selectin, a major endothelial adhesion receptor, interacts with Death receptor-3 present on metastatic colon carcinoma cells. This interaction confers metastatic properties to colon cancer cells by promoting the adhesion of cancer cells to endothelial cells and triggering the activation of the pro-migratory p38 and pro-survival ERK pathways in the cancer cells. In the present study, we investigated further the mechanisms by which the E-selectin-activated pathways downstream of DR3 confer a survival advantage to colon cancer cells. Methods Cell survival has been ascertained by using the WST-1 assay and by evaluating the activation of the PI3 kinase/NFκB survival axis. Apoptosis has been assayed by determining DNA fragmentation by Hoechst staining and by measuring cleavage of caspases-8 and -3. DR3 isoforms have been identified by PCR. For more precise quantification, targeted PCR reactions were carried out, and the amplified products were analyzed by automated chip-based microcapillary electrophoresis on an Agilent 2100 Bioanalyzer instrument. Results Interaction between DR3-expressing HT29 colon carcinoma cells and E-selectin induces the activation of the PI3K/Akt pathway. Moreover, p65/RelA, the anti-apoptotic subunit of NFκB, is rapidly translocated to the nucleus in response to E-selectin. This translocation is impaired by the PI3K inhibitor LY294002. Furthermore, inhibition of the PI3K/Akt pathway increases the cleavage of caspase 8 in colon cancer cells treated with E-selectin and this effect is still further increased when both ERK and PI3K pathways are concomitantly inhibited. Intriguingly, metastatic colon cancer cell lines such as HT

  19. [Effects of acupuncture on PI3K/Akt/mTOR signaling pathway in rats with premature ovarian failure].

    Science.gov (United States)

    Zhang, Yimin; Yu, Bin; Chen, Jia; Zhao, Zhisheng; Wang Jiali; Huang, Fasen; Lin, Yuee; Wang, Mengwei; Zhang, Yupei; Wei, Bo

    2015-01-01

    To explore the effects of acupuncture and medication on PI3K/Akt/mTOR signaling pathway in rats with premature ovarian failure. Ten of fifty SPF-grade female SD rats were randomly selected into a normal group, and the remaining 40 rats were treated with intraperitoneal injection of cyclophospha mide (30 mg/kg) for consecutive 5 days to establish rat model of premature ovarian failure. Thirty five successful rat models were randomly divided into a model group (9 cases), a medication group (9 cases), an acupuncture group A (9 cases) and an acupuncture group B (8 cases). The rats in the model group and normal group did not receive any treatment. The rats in the medication group were treated with intragastric administration of diethylstil bestrol, once a day. The rats in the acupuncture group A and acupuncture group B were respectively treated with acupuncture at different acupoints, twice a day. All the treatment was given for 4 weeks. After the treatment, enzyme-linked immunosorbent assay (ELISA) was applied to test the levels of estradiol (E2), progesterone (P), follicle stimulating hormone (FSH) and luteotropic hormone (LH). The ovarian tissue sample was processed with hematoxylin eosin (HE) staining as well as RNA and protein extraction to test the mRNA expression of estrogen receptor alpha (ERalpha), estrogen receptor beta (ERP), phosphatidylinositol 3-kinase/serine/threonine kinase (PI3K), protein kinase B (Akt) and mammalian target of rapamycin (mTOR). High-dose short-term in- tervention of cyclophosphamide could establish rat model of premature ovarian failure with a successful rate of 87.5%. Compared with the normal group, the vaginal smear in the model group was featured with signs of estro gen deficiency, early-follicle reduction, structural damage to the follicle, and reducing number of mature follicles; the level of E2 was significantly reduced (Pacupuncture groups, the levels of E2 was obviously increased (all Pacupuncture groups and medication group

  20. Inhibition of phospholipaseD2 increases hypoxia-induced human colon cancer cell apoptosis through inactivating of the PI3K/AKT signaling pathway.

    Science.gov (United States)

    Liu, Maoxi; Fu, Zhongxue; Wu, Xingye; Du, Kunli; Zhang, Shouru; Zeng, Li

    2016-05-01

    Hypoxia is a common feature of solid tumor, and is a direct stress that triggers apoptosis in many human cell types. As one of solid cancer, hypoxia exists in the whole course of colon cancer occurrence and progression. Our previous studies shown that hypoxia induce high expression of phospholipase D2 (PLD2) and survivin in colon cancer cells. However, the correlation between PLD2 and survivin in hypoxic colon cancer cells remains unknown. In this study, we observed significantly elevated PLD2 and survivin expression levels in colon cancer tissues and cells. This is a positive correlation between of them, and co-expression of PLD2 and survivin has a positive correlation with the clinicpatholic features including tumor size, TNM stage, and lymph node metastasis. We also found that hypoxia induced the activity of PLD increased significant mainly caused by PLD2 in colon cancer cells. However, inhibition the activity of PLD2 induced by hypoxia promotes the apoptosis of human colon cancer cells, as well as decreased the expression of apoptosis markers including survivin and bcl2. Moreover, the pharmacological inhibition of PI3K/AKT supported the hypothesis that promotes the apoptosis of hypoxic colon cancer cells by PLD2 activity inhibition may through inactivation of the PI3K/AKT signaling pathway. Furthermore, interference the PLD2 gene expression leaded to the apoptosis of hypoxic colon cancer cells increased and also decreased the expression level of survivin and bcl2 may through inactivation of PI3K/AKT signaling pathway. These results indicated that PLD2 play antiapoptotic role in colon cancer under hypoxic conditions, inhibition of the activity, or interference of PLD2 gene expression will benefit for the treatment of colon cancer patients.

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

    Science.gov (United States)

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

    2016-10-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

  3. PI3K/Akt pathway involving into apoptosis and invasion in human colon cancer cells LoVo.

    Science.gov (United States)

    Jiang, Qun Guang; Li, Tai Yuan; Liu, Dong Ning; Zhang, Hai Tao

    2014-05-01

    In this study we determined the effects of Curcumin on human colon cancer cells line LoVo. We found that Curcumin significantly inhibited the proliferation, migration and invasion, and clone formation of LoVo cells in a dose-dependent manner. Curcumin also dose-dependently reduced the phosphorylation of proteins Akt and increased expression levels of the genes caspase-3, cytochrome-c, Bax mRNA in LoVo cells. In addition, Curcumin dose-dependently decreased gene Bcl-2 mRNA expression. Similar results were observed in LoVo cells treated with LY294002. These in vitro studies suggest that Curcumin may play its anti-cancer actions partly via suppressing PI3K/Akt signal pathway in LoVo cells.

  4. PI3KC2{alpha}, a class II PI3K, is required for dynamin-independent internalization pathways

    DEFF Research Database (Denmark)

    Krag, Claudia; Malmberg, Emily Kim; Salcini, Anna Elisabetta

    2010-01-01

    Increasing evidence indicates that cellular uptake of several molecules can occur independently of functional dynamin, but the molecular players that regulate dynamin-independent endocytosis and the subsequent trafficking steps are still largely unknown. A survival-based short-hairpin (sh) RNA...... screen using a cell line expressing a diphtheria toxin receptor (DTR, officially known as HBEGF) anchored to GPI (DTR-GPI), which internalizes diphtheria toxin (DT, officially known as DTX) in a dynamin-independent manner, identified PI3KC2a, a class II phosphoinositide 3-kinase (PI3K), as a specific...... regulator of dynamin-independent DT internalization. We found that the internalization of several proteins that enter the cell through dynamin-independent pathways led to a relocalization of PI3KC2a to cargo-positive vesicles. Furthermore, downregulation of PI3KC2a impaired internalization of CD59 as well...

  5. c-Yes enhances tumor migration and invasion via PI3K/AKT pathway in epithelial ovarian cancer.

    Science.gov (United States)

    Jin, Yunfeng; Huang, Menghui; Wang, Yingying; Yi, Changying; Deng, Yan; Chen, Yannan; Jiang, Lifei; Wang, Juan; Shen, Qin; Liu, Rong; QinghuaXi

    2016-08-01

    Overexpression of c-Yes has been noted to correlation with several human cancers. However, the effects of c-Yes on epithelial ovarian cancer (EOC) development remain unclear. The aim of this study is going to prove the effects of c-Yes and related mechanisms in proliferation, metastasis and invasion of EOC. Immunohistochemical analysis was performed in 119 human EOC samples, and the data was correlated with clinic pathologic features. Furthermore, western blot analysis is performed for c-Yes in EOC samples and cell lines to evaluate their protein levels and molecular interaction. Kaplan-Meier survival analysis shows that the strong expression of c-Yes exhibited a significant correlation with poor prognosis in human EOC (PYes by shRNA inhibited the ability of migration and invasion in EOC cells via the PI3K/AKT pathway. In a word, these results suggested that c-Yes plays an important role in migration and invasion of EOC.

  6. SHIP2 on pI3K/Akt pathway in palmitic acid stimulated islet β cell.

    Science.gov (United States)

    Liu, Qingjuan; Wang, Ruiying; Zhou, Hong; Zhang, Lihui; Cao, Yanping; Wang, Xianjuan; Hao, Yongmei

    2015-01-01

    This study is to investigate the influence of SHIP2 on palmitic acid stimulated islet β cell and insulin secretion, as well as its role in pI3K/Akt pathway. We defined four groups: control, acid group, acid + NC siRNA group and acid + siRNA transfection group. The control was neither treated by palmitic acid nor transfection. The acid group was subjected to palmitic acid incubation. The acid + NC siRNA group was transiently transfected by NC siRNA, then was stimulated by palmitic acid. The acid + siRNA group was transiently transfected by siRNA, then was stimulated by palmitic acid. Cell proliferation and apoptosis were measured by MTT and flow cytometry. Immunocytochemistry, Western Blot and QPCR were designed to detect the expression of SHIP2, Akt, p-Akt protein and mRNA. Insulin secretion was tested by radioimmunoassay. The apoptosis rate in the acid + siRNA group was non-significantly lower than the acid group and the acid + NC siRNA group (P > 0.05). The expression levels of Akt phosphorylation in the acid + siRNA group was significantly higher than in the acid + NC siRNA group and the acid group (P acid + siRNA group was significantly more than the acid + NC siRNA group and the acid group (P < 0.05). SHIP2 silencing probably stimulates insulin secretion, which may be associated with the enhanced proliferation in the pI3K/Akt pathway.

  7. Quercetin attenuates high fructose feeding-induced atherosclerosis by suppressing inflammation and apoptosis via ROS-regulated PI3K/AKT signaling pathway.

    Science.gov (United States)

    Lu, Xue-Li; Zhao, Cui-Hua; Yao, Xin-Liang; Zhang, Han

    2017-01-01

    Quercetin is a dietary flavonoid compound extracted from various plants, such as apple and onions. Previous studies have revealed its anti-inflammatory, anti-cancer, antioxidant and anti-apoptotic activities. This study investigated the ability of quercetin to inhibit high fructose feeding- or LPS-induced atherosclerosis through regulating oxidative stress, apoptosis and inflammation response in vivo and in vitro experiments. 50 and 100mg/kg quercetin were used in our study, showing significant inhibitory role in high fructose-induced atherosclerosis via reducing reactive oxygen species (ROS) levels, Caspase-3 activation, inflammatory cytokines releasing, the number of terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL)-positive cells and collagen contents as well as modulating apoptosis- and inflammation-related proteins expression. We also explored the protective effects of quercetin on atherosclerosis by phosphatidylinositide 3-kinases (PI3K)/Protein kinase B (AKT)-associated Bcl-2/Caspase-3 and nuclear factor kappa B (NF-κB) signal pathways activation, promoting AKT and Bcl-2 expression and reducing Caspase-3 and NF-κB activation. Quercetin reduced the atherosclerotic plaque size in vivo in high fructose feeding-induced mice assessed by oil red O. Also, in vitro experiments, quercetin displayed inhibitory role in LPS-induced ROS production, inflammatory response and apoptosis, which were linked with PI3K/AKT-regulated Caspase-3 and NF-κB activation. In conclusion, our results showed that quercetin inhibited atherosclerotic plaque development in high fructose feeding mice via PI3K/AKT activation regulated by ROS.

  8. Adenovirus vector E4 gene regulates connexin 40 and 43 expression in endothelial cells via PKA and PI3K signal pathways.

    Science.gov (United States)

    Zhang, Fan; Cheng, Joseph; Lam, George; Jin, David K; Vincent, Loïc; Hackett, Neil R; Wang, Shiyang; Young, Lauren M; Hempstead, Barbara; Crystal, Ronald G; Rafii, Shahin

    2005-05-13

    Connexins (Cxs) provide a means for intercellular communication and play important roles in the pathophysiology of vascular cardiac diseases. Infection of endothelial cells (ECs) with first-generation E1/E3-deleted E4+ adenovirus (AdE4+) selectively modulates the survival and angiogenic potential of ECs by as of yet unrecognized mechanisms. We show here that AdE4+ vectors potentiate Cx expression in ECs in vitro and in mouse heart tissue. Infection of ECs with AdE4+, but not AdE4-, resulted in a time- and dose-dependent induction of junctional Cx40 expression and suppression of Cx43 protein and mRNA expression. Treatment of ECs with PKA inhibitor H89 or PI3K inhibitor LY294002 prevented the AdE4+-mediated regulation of Cx40 and Cx43 that was associated with diminished AdE4+-mediated survival of ECs. Moreover, both PKA activity and cAMP-response element (CRE)-binding activity were enhanced by treatment of ECs with AdE4+. However, there is no causal evidence of a cross-talk between the 2 modulatory pathways, PKA and PI3K. Remarkably, Cx40 immunostaining was markedly increased and Cx43 was decreased in the heart tissue of mice treated with intra-tracheal AdE4+. Taken together, these results suggest that AdE4+ may play an important role in the regulation of Cx expression in ECs, and that these effects are mediated by both the PKA/CREB and PI3K signaling pathways.

  9. WSTF promotes proliferation and invasion of lung cancer cells by inducing EMT via PI3K/Akt and IL-6/STAT3 signaling pathways.

    Science.gov (United States)

    Meng, Jin; Zhang, Xu-Tao; Liu, Xin-Li; Fan, Lei; Li, Chen; Sun, Yang; Liang, Xiao-Hua; Wang, Jian-Bo; Mei, Qi-Bing; Zhang, Feng; Zhang, Tao

    2016-11-01

    Williams syndrome transcription factor (WSTF), which is encoded by the BAZ1B gene, was first identified as a hemizygously deleted gene in patients with Williams syndrome. WSTF protein has been reported to be involved in transcription, replication, chromatin remodeling and DNA damage response, and also functions as a tyrosine protein kinase. However, the function of WSTF in cancer is not known. Here, we show that WSTF overexpression promotes proliferation, colony formation, migration and invasion of lung cancer A549 and H1299 cells. WSTF overexpression also promotes tumor growth and invasive abilities of lung cancer cells in mouse xenograft models. cDNA microarray and subsequent qRT-PCR validation revealed that WSTF overexpression significantly upregulated the expression of EMT (epithelial to mesenchymal transition) marker fibronectin (FN1) and EMT-inducing genes Fos and CEACAM6. The changes of EMT markers including downregulated E-cadherin and upregulated N-cadherin and FN1 were further confirmed at both mRNA and protein levels upon WSTF overexpression, with typical morphological changes of EMT. Furthermore, WSTF activates both PI3K/Akt and IL-6/STAT3 oncogenic signaling pathways. Treatment with PI3K inhibitor ZSTK474 or STAT3 inhibitor niclosamide reversed the effects of WSTF overexpression by inhibiting cell proliferation, migration and invasion, with decreased level of p-Akt, p-STAT3 and IL-6. ZSTK474 and niclosamide also reversed EMT markers and EMT-inducing proteins including Snail, Slug, Twist and CEACAM6 in WSTF-overexpressing A549 cells. Taken together, these results demonstrate that WSTF may act as an oncoprotein in lung cancer to accelerate tumor aggressiveness by promoting EMT via activation of PI3K/Akt and IL-6/STAT3 pathways. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Minoxidil sulfate induced the increase in blood-brain tumor barrier permeability through ROS/RhoA/PI3K/PKB signaling pathway.

    Science.gov (United States)

    Gu, Yan-ting; Xue, Yi-xue; Wang, Yan-feng; Wang, Jin-hui; Chen, Xia; ShangGuan, Qian-ru; Lian, Yan; Zhong, Lei; Meng, Ying-nan

    2013-12-01

    Adenosine 5'-triphosphate-sensitive potassium channel (KATP channel) activator, minoxidil sulfate (MS), can selectively increase the permeability of the blood-tumor barrier (BTB); however, the mechanism by which this occurs is still under investigation. Using a rat brain glioma (C6) model, we first examined the expression levels of occludin and claudin-5 at different time points after intracarotid infusion of MS (30 μg/kg/min) by western blotting. Compared to MS treatment for 0 min group, the protein expression levels of occludin and claudin-5 in brain tumor tissue of rats showed no changes within 1 h and began to decrease significantly after 2 h of MS infusion. Based on these findings, we then used an in vitro BTB model and selective inhibitors of diverse signaling pathways to investigate whether reactive oxygen species (ROS)/RhoA/PI3K/PKB pathway play a key role in the process of the increase of BTB permeability induced by MS. The inhibitor of ROS or RhoA or PI3K or PKB significantly attenuated the expression of tight junction (TJ) protein and the increase of the BTB permeability after 2 h of MS treatment. In addition, the significant increases in RhoA activity and PKB phosphorylation after MS administration were observed, which were partly inhibited by N-2-mercaptopropionyl glycine (MPG) or C3 exoenzyme or LY294002 pretreatment. The present study indicates that the activation of signaling cascades involving ROS/RhoA/PI3K/PKB in BTB was required for the increase of BTB permeability induced by MS. Taken together, all of these results suggested that MS might increase BTB permeability in a time-dependent manner by down-regulating TJ protein expression and this effect could be related to ROS/RhoA/PI3K/PKB signal pathway. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. sFlt-1 及 PI3 K/AKT通路与子痫前期相关性研究%Study on the correlation between sFlt-1 and PI3 K/AKT pathway in preeclampsia

    Institute of Scientific and Technical Information of China (English)

    姚念玲; 马佳佳; 李佳; 陈必良

    2015-01-01

    目的 探讨子痫前期的脐静脉内皮细胞中sFlt-1与PI3K/AKT通路的相关性. 从细胞分子水平研究子痫前期发生发展规律,寻找有效的分子治疗靶点. 方法 将人脐静脉内皮细胞( HUVECs)在体外进行原代培养及传代. 用实时定量PCR和Western-blot法分别检测sFlt-1、PI3Kp85α及p-AKT( ser473)在正常妊娠的HUVECs和子痫前期的HUVECs 及在经PI3K/AKT通路抑制剂LY294002作用的子痫前期HUVECs中的表达情况. 结果 实时定量PCR和Western-blot结果均显示sFlt-1、PI3Kp85α及p-AKT(ser473)在正常妊娠的HUVECs低表达;在子痫前期HUVECs中高表达;在LY294002作用后的子痫前期HUVECs中发现,阻断PI3K/AKT通路的同时sFlt-1的表达也发生了下调,差异有统计学意义(P<0.05). 结论 sFlt-1可能参与子痫前期的发病过程. PI3K/AKT信号通路可能参与子痫前期的病理过程,可能成为子痫前期有效的分子治疗靶点.%Objective To explore the correlation between sFlt-1 and PI3K/AKT pathway in the umbilical vein endothelial cells in preeclampsia, and also to investigate the incidence and development of preeclampsia from the molecular standpoint, so as to find out effective treatment target of the disorder.Methods Human umbilical vein endothelial cells(HUVECs)were cultured in vitro and developed into the next generation.The expression levels of sFlt-1, PI3Kp85αand p-AKT (ser473) in HUVECs of normal pregnancy, preeclampsia HUVECs, as well as preeclampsia HUVECs through the access of PI3K/AKT pathway inhibitor—LY294002, were detec-ted respectively by real time quantitative PCR and Western blot.Results Detection results indicated that there were low expressions of sFlt-1, PI3Kp85αand p-AKT (ser473) in the HUVECs of normal pregnancy, but there were high expressions of preeclampsia HU-VECs.Following the inhibition by LY294002, the level of preeclampsia HUVECs revealed that the expression level of sFlt-1 was also down-regulated, with the blocking of

  12. The New Synthetic H2S-Releasing SDSS Protects MC3T3-E1 Osteoblasts against H2O2-Induced Apoptosis by Suppressing Oxidative Stress, Inhibiting MAPKs, and Activating the PI3K/Akt Pathway.

    Science.gov (United States)

    Yan, Xiaofei; Wu, Haixia; Wu, Zhiyuan; Hua, Fei; Liang, Dong; Sun, Hong; Yang, Yong; Huang, Dejian; Bian, Jin-Song

    2017-01-01

    Reactive oxygen species (ROS) are important in osteoporosis development. Oxidative stress induces apoptosis of osteoblasts and arrest of their differentiation. Both Danshensu (DSS) and hydrogen sulfide (H2S) produce significant antioxidant effect in various systems. In this study, we synthesized SDSS, a novel H2S-releasing compound derived from DSS, and studied its antioxidant effect in an H2O2-induced MC3T3-E1 osteoblastic cell injury model. We first characterized the H2S releasing property of SDSS in both in vivo and in vitro models. HPLC chromatogram showed that intravenous injection of SDSS in adult rats released ADT-OH, a well proved H2S sustained-release moiety, within several minutes in the rat plasma. Using an H2S selective fluorescent probe, we further confirmed that SDSS released H2S in MC3T3-E1 osteoblastic cells. Biological studies revealed that SDSS had no significant toxic effect but produced protective effects against H2O2-induced MC3T3-E1 cell apoptosis. SDSS also reversed the arrest of cell differentiation caused by H2O2 treatment. This was caused by the stimulatory effect of SDSS on bone sialoprotein, runt-related transcription factor 2, collagen expression, alkaline phosphatase activity, and bone nodule formation. Further studies revealed that SDSS reversed the reduced superoxide dismutase activity and glutathione content, and the increased ROS production in H2O2 treated cells. In addition, SDSS significantly attenuated H2O2-induced activation of p38-, ERK1/2-, and JNK-MAPKs. SDSS also stimulated phosphatidylinositol 3-kinase/Akt signaling pathway. Blockade of this pathway attenuated the cytoprotective effect of SDSS. In conclusion, SDSS protects MC3T3-E1 cells against H2O2-induced apoptosis by suppressing oxidative stress, inhibiting MAPKs, and activating the phosphatidylinositol 3-kinase/Akt pathway.

  13. Leishmania mexicana amastigotes inhibit p38 and JNK and activate PI3K/AKT: role in the inhibition of apoptosis of dendritic cells.

    Science.gov (United States)

    Vázquez-López, R; Argueta-Donohué, J; Wilkins-Rodríguez, A; Escalona-Montaño, A; Aguirre-García, M; Gutiérrez-Kobeh, L

    2015-11-01

    Leishmania mexicana is the causal agent of cutaneous leishmaniasis in Mexico. Dendritic cells (DC) are one of the host cells of Leishmania parasites. Intracellular microorganisms inhibit host cell apoptosis as a strategy to ensure their survival in infected cells. We have previously shown that Leishmania mexicana promastigotes and amastigotes inhibit camptothecin-induced apoptosis of monocyte-derived dendritic cells (moDC), but the mechanisms underlying the inhibition of apoptosis of DC by Leishmania have not been established. MAP kinases and PI3K participate in the process of apoptosis and are modulated by different species of Leishmania. As shown in this study, the infection of moDC with L. mexicana amastigotes diminished significantly the phosphorylation of the MAP kinases p38 and JNK. The inhibition of both kinases diminished significantly DNA fragmentation in moDC stimulated with camptothecin. On the other hand, L. mexicana amastigotes were able to activate the anti-apoptotic pathways PI3K and AKT. Our results indicate that L. mexicana amastigotes have the capacity to diminish MAP kinases activation and activate PI3K and AKT, which is probably one of the strategies employed by L. mexicana amastigotes to inhibit apoptosis in the infected moDC.

  14. Effects of simulated microgravity on human umbilical vein endothelial cell angiogenesis and role of the PI3K-Akt-eNOS signal pathway.

    Directory of Open Access Journals (Sweden)

    Fei Shi

    Full Text Available Endothelial cells are very sensitive to microgravity and the morphological and functional changes in endothelial cells are believed to be at the basis of weightlessness-induced cardiovascular deconditioning. It has been shown that the proliferation, migration, and morphological differentiation of endothelial cells play critical roles in angiogenesis. However, the influence of microgravity on the ability of endothelial cells to foster angiogenesis remains to be explored in detail. In the present study, we used a clinostat to simulate microgravity, and we observed tube formation, migration, and expression of endothelial nitric oxide synthase (eNOS in human umbilical vein endothelial cells (HUVEC-C. Specific inhibitors of eNOS and phosphoinositide 3-kinase (PI3K were added to the culture medium and gravity-induced changes in the pathways that mediate angiogenesis were investigated. After 24 h of exposure to simulated microgravity, HUVEC-C tube formation and migration were significantly promoted.This was reversed by co-incubation with the specific inhibitor of N-nitro-L-arginine methyl ester hydrochloride (eNOS. Immunofluorescence assay, RT-PCR, and Western blot analysis demonstrated that eNOS expression in the HUVEC-C was significantly elevated after simulated microgravity exhibition. Ultrastructure observation via transmission electron microscope showed the number of caveolae organelles in the membrane of HUVEC-C to be significantly reduced. This was correlated with enhanced eNOS activity. Western blot analysis then showed that phosphorylation of eNOS and serine/threonine kinase (Akt were both up-regulated after exposure to simulated microgravity. However, the specific inhibitor of PI3K not only significantly downregulated the expression of phosphorylated Akt, but also downregulated the phosphorylation of eNOS. This suggested that the PI3K-Akt signal pathway might participate in modulating the activity of eNOS. In conclusion, the present study

  15. Apoptosis Induction of Human Prostate Carcinoma DU145 Cells by Diallyl Disulfide via Modulation of JNK and PI3K/AKT Signaling Pathways

    Directory of Open Access Journals (Sweden)

    Young Hyun Yoo

    2012-11-01

    Full Text Available Diallyl disulfide (DADS, a sulfur compound derived from garlic, has various biological properties, such as anticancer, antiangiogenic and anti-inflammatory effects. However, the mechanisms of action underlying the compound's anticancer activity have not been fully elucidated. In this study, the apoptotic effects of DADS were investigated in DU145 human prostate carcinoma cells. Our results showed that DADS markedly inhibited the growth of the DU145 cells by induction of apoptosis. Apoptosis was accompanied by modulation of Bcl-2 and inhibitor of apoptosis protein (IAP family proteins, depolarization of the mitochondrial membrane potential (MMP, ΔΨm and proteolytic activation of caspases. We also found that the expression of death-receptor 4 (DR4 and Fas ligand (FasL proteins was increased and that the level of intact Bid proteins was down-regulated by DADS. Moreover, treatment with DADS induced phosphorylation of mitogen-activated protein kinases (MAPKs, including extracellular-signal regulating kinase (ERK, p38 MAPK and c-Jun N-terminal kinase (JNK. A specific JNK inhibitor, SP600125, significantly blocked DADS-induced-apoptosis, whereas inhibitors of the ERK (PD98059 and p38 MAPK (SB203580 had no effect. The induction of apoptosis was also accompanied by inactivation of phosphatidylinositol 3-kinase (PI3K/Akt and the PI3K inhibitor LY29004 significantly increased DADS-induced cell death. These findings provide evidence demonstrating that the proapoptotic effect of DADS is mediated through the activation of JNK and the inhibition of the PI3K/Akt signaling pathway in DU145 cells.

  16. Inositol hexaphosphate suppresses growth and induces apoptosis in HT-29 colorectal cancer cells in culture: PI3K/Akt pathway as a potential target.

    Science.gov (United States)

    Liu, Guiyuan; Song, Yang; Cui, Lianhua; Wen, Zhaoxia; Lu, Xiaoqing

    2015-01-01

    Inositol hexaphosphate (IP6) is a polyphosphorylated carbohydrate that is present in high amounts in almost all plants and mammalian cells. IP6 induces apoptosis in multiple types of cancer cells, including prostate cancer, breast cancer, skin tumor, liver cancer and colorectal cancer. However, little is known regarding the molecular mechanisms of its anticancer effects. Therefore, this study was conducted to investigate the activity of IP6 against human colorectal cancer cells (HT-29) and to determine whether the IP6 regulates apoptosis in HT-29 cells by inhibiting the PI3K/Akt signaling pathway. A human colorectal cancer cell line (HT-29) was used for the study. HT-29 cells were treated with 0, 50, 100, 200, and 400 μg/mL of IP6. The MTT colorimetric assay was used to observe the proliferation of HT-29 in vitro, and flow cytometry (FCM) was used to analyze the apoptosis of the HT-29 cells. The relative mRNA expression was determined by real-time PCR, and relative protein levels were analyzed by Western blot analysis. The results of MTT showed that HT-29 cells underwent inhibition of proliferation after exposure to IP6 (100-400 μg/mL) for 12 and 48 h, and this inhibition clearly relied on time and dosage. IP6 induced apoptosis in HT-29 cells in a dose-dependent manner. The mRNA and protein expression of PI3K and Akt decreased in the groups treated with IP6, and IP6 inhibited the phosphorylation of Akt (pAkt), whereas increased the expression of its downstream effector, caspase-9. Our results suggested that by targeting PI3K/Akt pathway, IP6 suppresses cell survival and proliferation, but induces death in HT-29 cells.

  17. Ozone oil promotes wound healing by increasing the migration of fibroblasts via PI3K/Akt/mTOR signaling pathway.

    Science.gov (United States)

    Xiao, Weirong; Tang, Hua; Wu, Meng; Liao, Yangying; Li, Ke; Li, Lan; Xu, Xiaopeng

    2017-09-01

    Background: Skin injury affects millions of people via the uncontrolled inflammation and infection. Many cellular components including fibroblasts and signaling pathways such as TGF-β were activated to facilitate the wound healing to repair injured tissues. Methods and Results: C57BL/6 female mice were divided into control and ozone oil treated groups. Excisional wounds were created on the dorsal skin and the fibroblasts were isolated from granulation tissues. The skin injured mouse model revealed that ozone oil could significantly decrease the wound area and accelerate wound healing compared with control group. QPCR and western blotting assays showed that ozone oil upregulated collagen I, α-SMA and TGF-β1 mRNA and protein levels in fibroblasts. Wound healing assay demonstrated that ozone oil could increase the migration of fibroblasts. Western blotting assay demonstrated that ozone oil increased the EMT process of fibroblasts via upregulating fibronectin, vimentin, N-cadherin, MMP-2, MMP-9, IGFBP-3, IGFBP5 and IGFBP6 and decreasing epithelial protein E-cadherin and cellular senescence marker p16 expression. Mechanistically, western blotting assay revealed that ozone oil increased the phosphorylation of PI3K, Akt and mTOR to regulate the EMT process, while inhibition of PI3K reversed this effect of ozone oil. At last, the results from Cytometric Bead Array demonstrated ozone oil significantly decreased the inflammation in fibroblasts. Conclusion: Our results demonstrated ozone oil facilitated the wound healing via increasing fibroblast migration and EMT process via PI3K/Akt/mTOR signaling pathway in vivo and vitro. The cellular and molecular mechanisms we found here may provide new therapeutic targets for the treatment of skin injury. ©2017 The Author(s).

  18. Overexpression of SDF-1α enhanced migration and engraftment of cardiac stem cells and reduced infarcted size via CXCR4/PI3K pathway.

    Directory of Open Access Journals (Sweden)

    Kui Wang

    Full Text Available Cardiac stem cells (CSCs can home to the infarcted area and regenerate myocardium. Stromal cell-derived factor-1α/C-X-C chemokine receptor type 4 (SDF-1α/CXCR4 axis is pivotal in inducing CSCs migration. However, the mechanisms remain unclear. This study set out to detect if SDF-1α promotes migration and engraftment of CSCs through the CXCR4/PI3K (phosphatidylinositol 3-kinase pathway. In the in vitro experiment, c-kit+ cells were isolated from neonatal mouse heart fragment culture by magnetic cell sorting. Fluorescence-activated cell sorting results demonstrated that a few c-kit+ cells expressed CD45 (4.54% and Sca-1 (2.58%, the hematopoietic stem cell marker. Conditioned culture could induce c-kit+ cells multipotent differentiation, which was confirmed by cardiac troponin I (cTn-I, α-smooth muscle actin (α-SMA, and von Willebrand factor (vWF staining. In vitro chemotaxis assays were performed using Transwell cell chambers to detect CSCs migration. The results showed that the cardiomyocytes infected with rAAV1-SDF-1α-eGFP significantly increased SDF-1α concentration, 5-fold more in supernatant than that in the control group, and subsequently attracted more CSCs migration. This effect was diminished by administration of AMD3100 (10 µg/ml, CXCR4 antagonist or LY294002 (20 µmol/L, PI3K inhibitor. In myocardial infarction mice, overexpression of SDF-1α in the infarcted area by rAAV1-SDF-1α-eGFP infection resulted in more CSCs retention to the infarcted myocardium, a higher percentage of proliferation, and reduced infarcted area which was attenuated by AMD3100 or ly294002 pretreatment. These results indicated that overexpression of SDF-1α enhanced CSCs migration in vitro and engraftment of transplanted CSCs and reduced infarcted size via CXCR4/PI3K pathway.

  19. The effect of Liuwei Dihuang decoction on PI3K/Akt signaling pathway in liver of type 2 diabetes mellitus (T2DM) rats with insulin resistance.

    Science.gov (United States)

    Dai, Bing; Wu, Qinxuan; Zeng, Chengxi; Zhang, Jiani; Cao, Luting; Xiao, Zizeng; Yang, Menglin

    2016-11-04

    Liuwei Dihaung decoction (LWDHT) is a well-known classic traditional Chinese medicine formula, consists of six herbs including Rehmannia glutinosa Libosch.(family: Scrophulariaceae), Cornus officinalis Sieb.(family: Cornaceae), Dioscorea opposite Thunb.(family: Dioscoreaceae), Alisma orientale(G. Samuelsson) Juz (family: Alismataceae), Poria cocos (Schw.) Wolf (family: Polyporaceae) and Paeonia suffruticosa Andrews (family: Paeoniaceae). It has been used in the treatment of many types of diseases with signs of deficiency of Yin in the kidneys in China clinically. This study is aimed at investigating the effect of Liuwei dihuang decoction on PI3K/Akt signaling pathway in liver of T2DM rats with insulin resistance. T2DM model was induced in male Sprague-Dawley (SD) rats by high sugar and high fat diets combined with small dose of streptozocin (STZ) injection. The successful T2DM rats were randomly allocated three group--vehicle group, positive control group and Liuwei Dihuang decoction group. After 12-weeks treatment with distilled water, rosiglitazone and LWDHT by intragastric administration respectively, the rats were put to death in batches. The variance of fasting blood glucose (FBG) and fasting insulin (FINS) in serum were determined, the pathological changes of each rats' liver were observed by hematoxylin-eosin (HE) staining, the expression of insulin receptor substrate 2(IRS2), phosphatidylinositol 3-kinase (PI3K) and protein kinas B (Akt) involving the canonical PI3K/Akt signaling pathway were detected by Real-time fluorescent quantitative PCR (RT-PCR), and the expression level of IRS2, PI3K, Akt protein and phosphorylated IRS2, PI3K, Akt protein were evaluated by Western Blot. All the data were analyzed by SPSS 17.0. Four weeks of treatment with LWDHT could significantly decrease the level of FBG and FINS in serum, improve the cellular morphology of liver, kidney, pancreas tissue, and the expression of IRS2, PI3K, Akt mRNA and phosphorylated IRS2, PI3K, Akt

  20. Daucus carota Pentane-Based Fractions Suppress Proliferation and Induce Apoptosis in Human Colon Adenocarcinoma HT-29 Cells by Inhibiting the MAPK and PI3K Pathways.

    Science.gov (United States)

    Shebaby, Wassim N; Bodman-Smith, K B; Mansour, Anthony; Mroueh, Mohamad; Taleb, Robin I; El-Sibai, Mirvat; Daher, Costantine F

    2015-07-01

    Daucus carota L. ssp. carota (Apiacea, wild carrot, Queen Anne's lace) has been used in folk medicine throughout the world and recently was shown to possess anticancer and antioxidant activities. This study aims to determine the anticancer activity of the pentane fraction (F1) and the 1:1 pentane:diethyl ether fraction (F2) of the Daucus Carota oil extract (DCOE) against human colon adenocarcinoma cell lines (HT-29 and Caco-2). Treatment of cells with various concentrations of F1 or F2 fractions produced a dose-dependent inhibition of cell proliferation. Flow cytometric analysis indicated that both fractions induced sub-G1 phase accumulation and increased apoptotic cell death. Western blot revealed the activation of caspase-3, PARP cleavage, and a considerable increase in Bax and p53 levels, and a decrease in Bcl-2 level. Treatment of HT-29 cells with either fraction markedly decreased the levels of both phosphorylated Erk and Akt. Furthermore, the combined treatment of F1 or F2 with wortmannin showed no added inhibition of cell survival suggesting an effect of F1 or F2 through the phosphatidyl inositol 3-kinase (PI3K) pathway. This study proposes that DCOE fractions (F1 and F2) inhibit cell proliferation by inducing cell cycle arrest and apoptosis in HT-29 cells through the suppression of mitogen-activated protein kinase (MAPK)/Erk and PI3K/Akt pathways.

  1. 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.

    Science.gov (United States)

    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.

  2. Combination of Endothelial-Monocyte-Activating Polypeptide-II with Temozolomide Suppress Malignant Biological Behaviors of Human Glioblastoma Stem Cells via miR-590-3p/MACC1 Inhibiting PI3K/AKT/mTOR Signal Pathway

    Science.gov (United States)

    Zhou, Wei; Liu, Libo; Xue, Yixue; Zheng, Jian; Liu, Xiaobai; Ma, Jun; Li, Zhen; Liu, Yunhui

    2017-01-01

    This study aims to investigate the effect of Endothelial-Monocyte-Activating Polypeptide-II (EMAP-II) combined with temozolomide (TMZ) upon glioblastoma stem cells (GSCs) and its possible molecular mechanisms. In this study, combination of EMAP-II with TMZ inhibited cell viability, migration and invasion in GSCs, and autophagy inhibitor 3-methyl adenine (3-MA) and chloroquine (CQ) partly reverse the anti-proliferative effect of the combination treatment. Autophagic vacuoles were formed in GSCs after the combination therapy, accompanied with the up-regulation of LC3-II and Beclin-1 as well as the down-regulation of p62/SQSTM1. Further, miR-590-3p was up-regulated and Metastasis-associated in colon cancer 1 (MACC1) was down-regulated by the combination treatment in GSCs; MiR-590-3p overexpression and MACC1 knockdown up-regulated LC3-II and Beclin-1 as well as down-regulated p62/SQSTM1 in GSCs; MACC1 was identified as a direct target of miR-590-3p, mediating the effects of miR-590-3p in the combination treatment. Furthermore, the combination treatment and MACC1 knockdown decreased p-PI3K, p-Akt, p-mTOR, p-S6 and p-4EBP in GSCs; PI3K/Akt agonist insulin-like growth factor-1(IGF-1) partly blocked the effect of the combination treatment. Moreover, in vivo xenograft models, the mice given stable overexpressed miR-590-3p cells and treated with EMAP-II and TMZ had the smallest tumor sizes, besides, miR-590-3p + EMAP-II + TMZ up-regulated the expression level of miR-590-3p, LC3-II and Beclin-1 as well as down-regulated p62/SQSTM1. In conclusion, these results elucidated anovel molecular mechanism of EMAP-II in combination with TMZ suppressed malignant biological behaviors of GSCs via miR-590-3p/MACC1 inhibiting PI3K/AKT/mTOR signaling pathway, and might provide potential therapeutic approaches for human GSCs.

  3. Neuroprotective Effects of Salidroside in the MPTP Mouse Model of Parkinson’s Disease: Involvement of the PI3K/Akt/GSK3β Pathway

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    Wei Zhang

    2016-01-01

    Full Text Available The degenerative loss through apoptosis of dopaminergic neurons in the substantia nigra pars compacta plays a primary role in the progression of Parkinson’s disease (PD. Our in vitro experiments suggested that salidroside (Sal could protect against 1-methyl-4-phenylpyridine-induced cell apoptosis in part by regulating the PI3K/Akt/GSK3β pathway. The current study aims to increase our understanding of the protective mechanisms of Sal in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropypridine- (MPTP- induced PD mouse model. We found that pretreatment with Sal could protect against MPTP-induced increase of the time of turning downwards and climbing down to the floor. Sal also prevented MPTP-induced decrease of locomotion frequency and the increase of the immobile time. Sal provided a protection of in MPTP-induced loss of tyrosine hydroxylase-positive neurons in SNpc and the level of DA, DOPAC, and HVA in the striatum. Furthermore, Sal could increase the phosphorylation level of Akt and GSK3β, upregulate the ratio of Bcl-2/Bax, and inhibit the activation of caspase-3, caspase-6, and caspase-9. These results show that Sal prevents the loss of dopaminergic neurons and the PI3K/Akt/GSK3β pathway signaling pathway may have mediated the protection of Sal against MPTP, suggesting that Sal may be a potential candidate in neuroprotective treatment for PD.

  4. IGF-1 promotes Brn-4 expression and neuronal differentiation of neural stem cells via the PI3K/Akt pathway.

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    Xinhua Zhang

    Full Text Available Our previous studies indicated that transcription factor Brn-4 is upregulated in the surgically denervated hippocampus in vivo, promoting neuronal differentiation of hippocampal neural stem cells (NSCs in vitro. The molecules mediating Brn-4 upregulation in the denervated hippocampus remain unknown. In this study we examined the levels of insulin-like growth factor-1 (IGF-1 in hippocampus following denervation. Surgical denervation led to a significant increase in IGF-1 expression in vivo. We also report that IGF-1 treatment on NSCs in vitro led to a marked acceleration of Brn-4 expression and cell differentiation down neuronal pathways. The promotion effects were blocked by PI3K-specific inhibitor (LY294002, but not MAPK inhibitor (PD98059; levels of phospho-Akt were increased by IGF-1 treatment. In addition, inhibition of IGF-1 receptor (AG1024 and mTOR (rapamycin both attenuated the increased expression of Brn-4 induced by IGF-1. Together, the results demonstrated that upregulation of IGF-1 induced by hippocampal denervation injury leads to activation of the PI3K/Akt signaling pathway, which in turn gives rise to upregulation of the Brn-4 and subsequent stem cell differentiation down neuronal pathways.

  5. 2-methoxyestradiol induces vasodilation by stimulating NO release via PPARγ/PI3K/Akt pathway.

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    Chen, Weiyu; Cui, Yuhong; Zheng, Shuhui; Huang, Jinghe; Li, Ping; Simoncini, Tommaso; Zhang, Yongfu; Fu, Xiaodong

    2015-01-01

    The endogenous estradiol metabolite 2-methoxyestradiol (2-ME) reduces atherosclerotic lesion formation, while the underlying mechanisms remain obscure. In this work, we investigated the vasodilatory effect of 2-ME and the role of nitric oxide (NO) involved. In vivo studies using noninvasive tail-cuff methods showed that 2-ME decreased blood pressure in Sprague Dawley rats. Furthermore, in vitro studies showed that cumulative addition of 2-ME to the aorta caused a dose- and endothelium-dependent vasodilation. This effect was unaffected by the pretreatment with the pure estrogen receptor antagonist ICI 182,780, but was largely impaired by endothelial nitric oxide synthase (eNOS) inhibitor NG-nitro-L-arginine methyl ester (L-NAME) or by phosphoinositide 3-kinase (PI3K) inhibitor wortmannin (WM). Moreover, 2-ME(10-7 ∼10-5 M)enhanced phosphorylation of Akt and eNOS and promoted NO release from cultured human umbilical endothelial cells (HUVECs). These effects were blocked by PI3K inhibitor WM, or by the transfection with Akt specific siRNA, indicating that endothelial Akt/eNOS/NO cascade plays a crucial role in 2-ME-induced vasodilation. The peroxisome proliferator-activated receptor γ (PPARγ) mRNA and protein expression were detected in HUVECs and the antagonist GW9662 or the transfection with specific PPARγ siRNA inhibited 2-ME-induced eNOS and Akt phosphorylation, leading to the impairment of NO production and vasodilation. In conclusion, 2-ME induces vasodilation by stimulating NO release. These actions may be mediated by PPARγ and the subsequent activation of Akt/eNOS cascade in vascular endothelial cells.

  6. Synergistic Interactions with PI3K Inhibition that Induce Apoptosis. | Office of Cancer Genomics

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    Activating mutations involving the PI3K pathway occur frequently in human cancers. However, PI3K inhibitors primarily induce cell cycle arrest, leaving a significant reservoir of tumor cells that may acquire or exhibit resistance. We searched for genes that are required for the survival of PI3K mutant cancer cells in the presence of PI3K inhibition by conducting a genome scale shRNA-based apoptosis screen in a PIK3CA mutant human breast cancer cell. We identified 5 genes (PIM2, ZAK, TACC1, ZFR, ZNF565) whose suppression induced cell death upon PI3K inhibition.

  7. PI3K / Akt Signaling Pathway on Expression of BACE1 mRNA in Hippocampus Neurons%胰岛素信号通路PI3K/Akt对海马神经元β-淀粉样前体蛋白裂解酶1mRNA水平的影响

    Institute of Scientific and Technical Information of China (English)

    王国祥; 李洁颖; 晏勇

    2011-01-01

    Objective To investigate the effect of beta-site amyloid precursor protein cleaving enzyme-1 (BACE1) mRNA on phosphatidylinosi-tol-3 kinase / serine threohine kinase( PI3K / Akt) signaling pathway in the hippocampus neurons of rat brain. Methods Insulin and the specific inhibitor of PI3 K Wortmannin were used to activate and inhibit the signaling pathway , 20SD rats randomly divided into four group: blank control group, sham-operated group, insulin group and Wortmannin group. RT-PCR were used to analyse the proteins related to the insulin signaling Akt and BACE1 mRNA. Results The expression of signaling pathway downstream molecules Akt mRNA were up-regulated(p =0. 047, p = 0. 002) ,the expression of BACE1 mRNA significantly down-regulated(p =0. 004 ,p =0. 01 )in insulin group. The expression of BACE1 mRNA was opposite after treatment with inhibitor of PDK( p =0. 039 ,p =0. 018) ,Akt mRNA were also inhibited(p =0. 002,p =0. 039). Conclusion PI3K / Akt signaling pathway might effect the expression of BACE1, which demonstrates that impaired signaling pathway shoud make the amyloid precursor protein easy to be processed by BACE1, thus to involve the pathology of Alzheimer's disease.%目的 通过胰岛素和磷脂酰肌醇-3激酶(PI3K)抑制剂渥曼青霉素(wortmannin)对PI3K/丝氨酸苏氨酸蛋白激酶(PI3K/Akt)信号通路的激活和抑制作用,观察PI3K/Akt信号通路对海马神经元β-淀粉样前体蛋白裂解酶1(BACE1)mRNA水平表达的影响.方法 20只SD大鼠随机分为空白对照组、假手术组、胰岛素组和渥曼青霉素组,海马立体定向注射胰岛素和PI3K抑制剂渥曼青霉素.逆转录-聚合酶链反应(RT-PCR)检测PI3K/Akt信号传导下游蛋白Akt以及BACE1 mRNA水平.结果 注射胰岛素的海马PI3K信号通路下游信号分子:Akt mRNA表达上调(分别较空白和阴性对照组p=0.047,p =0.002),而BACE1 mRNA表达下调(分别较空白和阴性对照组p=0.004,p=0.01).渥曼青霉素组的PI3K

  8. Telmisartan attenuates monocrotaline-induced pulmonary artery endothelial dysfunction through a PPAR gamma-dependent PI3K/Akt/eNOS pathway.

    Science.gov (United States)

    Li, He; Lu, Wei; Cai, Wei-Wei; Wang, Pei-Jian; Zhang, Ning; Yu, Chang-Ping; Wang, Dong-Liang; Liu, Bai-Cheng; Sun, Wei

    2014-06-01

    Pulmonary artery endothelial dysfunction has been demonstrated in pulmonary arterial hypertension (PAH). Telmisartan has beneficial effects in endothelial function in PAH patients; however, the underlying mechanisms for these effects remain unknown. In this study, we observed the effects of telmisartan on monocrotaline (MCT)-induced Sprague Dawley (SD) rat model of PAH. After a single-dose injection of MCT (60 mg/kg), oral administration of telmisartan (10 mg/kg/d) was started from day 1 to day 28 or with saline as MCT control. The vasorelaxation and remodelling of pulmonary arteries; the expression of peroxisome proliferator-activated receptor γ (PPARγ), Akt, eNOS; levels of phosphorylation of Akt (p-Akt) and phosphorylation of eNOS (p-eNOS) were analysed in isolated rat pulmonary arteries and cultured human pulmonary artery endothelial cells (HPAECs). Compared to MCT control group, telmisartan treatment ameliorated pulmonary artery endothelial dysfunction and remodelling, prevented the elevation of right ventricular systolic pressure (RVSP) induced by MCT. Immunoblotting results indicated lower levels of PPARγ, p-Akt and p-eNOS in pulmonary arteries treated with MCT alone and levels were significantly restored by co-treatment with telmisartan. In isolated pulmonary arteries, the impaired endothelium-dependent vasorelaxation of pulmonary arteries was improved following incubation with telmisartan for 12 h, whereas this effect was blocked by the inhibition of either PPARγ or phosphoinositide 3-kinase (PI3K) signals transduction. In cultured HPAECs, treatment with telmisartan increased PPARγ expression and promoted the phosphorylation of Akt and eNOS, thereby increasing the production of NO. These effects were abolished by the inhibition of PPARγ or PI3K. Telmisartan protected against endothelial dysfunction in MCT-induced PAH through a PPARγ-dependent PI3K/Akt/eNOS pathway. Thus, telmisartan may be a promising therapeutic strategy for patients with a high

  9. Catalase expression in MCF-7 breast cancer cells is mainly controlled by PI3K/Akt/mTor signaling pathway.

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    Glorieux, Christophe; Auquier, Julien; Dejeans, Nicolas; Sid, Brice; Demoulin, Jean-Baptiste; Bertrand, Luc; Verrax, Julien; Calderon, Pedro Buc

    2014-05-15

    Catalase is an antioxidant enzyme that catalyzes mainly the transformation of hydrogen peroxide into water and oxygen. Although catalase is frequently down-regulated in tumors the underlying mechanism remains unclear. Few transcription factors have been reported to directly bind the human catalase promoter. Among them FoxO3a has been proposed as a positive regulator of catalase expression. Therefore, we decided to study the role of the transcription factor FoxO3a and the phosphatidylinositol-3 kinase (PI3K) signaling pathway, which regulates FoxO3a, in the expression of catalase. To this end, we developed an experimental model of mammary breast MCF-7 cancer cells that acquire resistance to oxidative stress, the so-called Resox cells, in which catalase is overexpressed as compared with MCF-7 parental cell line. In Resox cells, Akt expression is decreased but its phosphorylation is enhanced when compared with MCF-7 cells. A similar profile is observed for FoxO3a, with less total protein but more phosphorylated FoxO3a in Resox cells, correlating with its higher Akt activity. The modulation of FoxO3a expression by knockdown and overexpression strategies did not affect catalase expression, neither in MCF-7 nor in Resox cells. Inhibition of PI3K and mTOR by LY295002 and rapamycin, respectively, decreases the phosphorylation of downstream targets (i.e. GSK3β and p70S6K) and leads to an increase of catalase expression only in MCF-7 but not in Resox cells. In conclusion, FoxO3a does not appear to play a critical role in the regulation of catalase expression in both cancer cells. Only MCF-7 cells are sensitive and dependent on PI3K/Akt/mTOR signaling.

  10. Interleukin-21 promotes osteoclastogenesis in RAW264.7 cells through the PI3K/AKT signaling pathway independently of RANKL

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    Xing, Rui; Zhang, Yingjian; Li, Changhong; Sun, Lin; Yang, Lin; Zhao, Jinxia; Liu, Xiangyuan

    2016-01-01

    Cytokines play a key role in the bone destruction of rheumatoid arthritis (RA). Interleukin-21 (IL-21) promotes osteoclastogenesis in RA in a receptor activator of nuclear factor-κB ligand (RANKL)-dependent way. Whether IL-21 is capable of promoting osteoclastogenesis directly in the absence of RANKL remains unknown. In the present study, we examined the osteoclastogenic activity of IL-21 in RAW264.7 cells in the absence of RANKL. We found that IL-21 enhanced osteoclastogenesis and this was demonstrated by increased numbers of tartrate-resistant acid phosphatase (TRAP)-positive stained, multinucleated cells compared with the negative control. Western blot analysis and immunocytochemistry showed the positive expression of calcitonin receptor (CTR) in the IL-21 group. RT-PCR and RT-qPCR also verified the increased mRNA expression of CTR and cathepsin K in the IL-21 group compared with the negative control. The scanning electronic microscope images showed a few resorption pits on the bone slices cultured with IL-21. The phosphoinositide 3-kinase (PI3K)/AKT pathway inhibitor LY294002 significantly suppressed IL-21-induced osteoclastogenesis. Taken together, these findings suggest that IL-21 has direct osteoclastogenic potential independently of RANKL. IL-21 may promote osteoclastogenesis through the PI3K/AKT signaling pathway. Therapy targeting IL-21 may be of value in preventing bone erosions in patients with RA. PMID:27599586

  11. Dynamics of GFP-Fusion p110α and p110β Isoforms of PI3K Signaling Pathway in Normal and Cancer Cells.

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    Singh, Paramjeet; Dar, Mohd Saleem; Singh, Gurjinder; Jamwal, Gayatri; Sharma, Parduman Raj; Ahmad, Muzamil; Dar, Mohd Jamal

    2016-12-01

    Cancer therapeutics is a hot subject and PI3K class 1A isoforms (p110α and p110β) are pursued as major targets. Genetic analysis, biochemical approaches, and structural studies have demonstrated crucial roles for these isoforms in several physiological processes. p110α is critical for insulin signaling, whereas p110β is essential for the growth and differs from p110α in many ways. Here, we have generated GFP-fusion clones of wildtype and mutant version of p110α and p110β and expressed them in HEK293 and cancer cells to examine their subcellular localization and their impact on downstream signaling. In HEK293 cells, p110β GFP-fusion protein is translocated into the nucleus, whereas p110α-GFP stays exclusively in the cytoplasm. This study demonstrates that p110α and p110β oncogenecity, kinase activity, and interaction with p85 regulatory subunit does not have any impact on their subcellular localization. PI3K pathway specific inhibitor, LY294002, abrogated PI3K signaling by reducing pAkt levels, however, the subcellular localization of p110α and p110β remained unchanged. Furthermore, we analyzed the expression of recombinant p110α and p110β in a panel of human cancer cells and observed remarkable differences in their expression levels. The differential expression of recombinant p110α and p110β was observed to be mainly regulated by the endogenous levels of pAkt. Unlike in HEK293, p110α showed nuclear localization in cancer cells in a similar fashion to p110β. Moreover, we observed the PI3K signaling activities in low pAkt expressing cells are mediated by PDK1 and S6K proteins. Finally, p110α and p110β were seen to play an essential role in promoting the cell cycle progression in MCF-7 and HCT-116 cells. J. Cell. Biochem. 117: 2864-2874, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  12. Comparative mRNA Expression of eEF1A Isoforms and a PI3K/Akt/mTOR Pathway in a Cellular Model of Parkinson’s Disease

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    Kawinthra Khwanraj

    2016-01-01

    Full Text Available The PI3K/Akt/mTOR pathway is one of dysregulated pathways in Parkinson’s disease (PD. Previous studies in nonneuronal cells showed that Akt regulation can be increased by eukaryotic protein elongation factor 1 alpha 2 (eEF1A2. eEF1A2 is proposed to contribute protection against apoptotic death, likely through activation of the PI3K/Akt pathway. Whether eEF1A2 plays a role in the prevention of cell death in PD has not been investigated. Recently, gene profiling on dopaminergic neurons from postmortem PD patients showed both upregulation and downregulation of some PI3K and mTOR genes. In this paper, the expression of all gene members of the PI3K/Akt/mTOR pathway in relation to those of the eEF1A isoforms in a cellular model of PD was investigated at the mRNA level. The results showed a similar trend of upregulation of genes of the eEF1A isoforms (eEF1A1 and eEF1A2 and of the PI3K (classes I–III/Akt (Akt1, Akt2, and Akt3/mTOR (mTORC1 and mTORC2 pathway in both nondifferentiated and differentiated SH-SY5Y dopaminergic cells treated with 1-methyl-4-phenylpyridinium (MPP+. Upregulation of eEF1A2, Akt1, and mTORC1 was consistent with the relative increase of eEF1A2, Akt, phospho-Akt, and mTORC1 proteins. The possible role of eEF1A isoforms in the regulation of the PI3K/Akt/mTOR pathway in PD is discussed.

  13. α-Mangostin Suppresses the Viability and Epithelial-Mesenchymal Transition of Pancreatic Cancer Cells by Downregulating the PI3K/Akt Pathway