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Sample records for akt survival pathway

  1. AKT/GSK3β signaling pathway is critically involved in human pluripotent stem cell survival

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    Romorini, Leonardo; Garate, Ximena; Neiman, Gabriel; Luzzani, Carlos; Furmento, Verónica Alejandra; Guberman, Alejandra Sonia; Sevlever, Gustavo Emilio; Scassa, María Elida; Miriuka, Santiago Gabriel

    2016-01-01

    Human embryonic and induced pluripotent stem cells are self-renewing pluripotent stem cells (PSC) that can differentiate into a wide range of specialized cells. Basic fibroblast growth factor is essential for PSC survival, stemness and self-renewal. PI3K/AKT pathway regulates cell viability and apoptosis in many cell types. Although it has been demonstrated that PI3K/AKT activation by bFGF is relevant for PSC stemness maintenance its role on PSC survival remains elusive. In this study we explored the molecular mechanisms involved in the regulation of PSC survival by AKT. We found that inhibition of AKT with three non-structurally related inhibitors (GSK690693, AKT inhibitor VIII and AKT inhibitor IV) decreased cell viability and induced apoptosis. We observed a rapid increase in phosphatidylserine translocation and in the extent of DNA fragmentation after inhibitors addition. Moreover, abrogation of AKT activity led to Caspase-9, Caspase-3, and PARP cleavage. Importantly, we demonstrated by pharmacological inhibition and siRNA knockdown that GSK3β signaling is responsible, at least in part, of the apoptosis triggered by AKT inhibition. Moreover, GSK3β inhibition decreases basal apoptosis rate and promotes PSC proliferation. In conclusion, we demonstrated that AKT activation prevents apoptosis, partly through inhibition of GSK3β, and thus results relevant for PSC survival. PMID:27762303

  2. Nitric oxide promotes survival of cerebellar granule neurons cultured in vitro through the Akt pathway

    Institute of Scientific and Technical Information of China (English)

    Lin Wang; Mei Li; Lihua Zhou

    2011-01-01

    In this study, cerebellar granule neurons were used to examine the role of nitric oxide on cell survival. The N-methyl-D-aspartic acid receptor antagonist, MK-801, and the soluble guanylate cyclase antagonist, 1H-[1, 2, 4]oxadiazolo-[4, 3-a] quinoxalin-1-one, decreased cell viability, induced caspase-3, and decreased phosphorylated-Akt levels, suggesting that blockade of nitric oxide production promotes apoptosis of differentiating cerebellar granule neurons. After administration of sodium nitroprusside, an endogenous nitric oxide donor, cell viability recovered,caspase-3 expression was decreased, and phosphorylated-Akt levels increased. This study provides direct evidence that nitric oxide can sustain the survival of developing cerebellar granule neurons in vitro through the nitric oxide-Akt pathway. Moreover, endogenous nitric oxide exerts these effects in a cyclic guanosine monophosphate-dependent manner while exogenous nitric oxide does so in a cyclic guanosine monophosphate-independent manner.

  3. Estradiol promotes pentose phosphate pathway addiction and cell survival via reactivation of Akt in mTORC1 hyperactive cells.

    Science.gov (United States)

    Sun, Y; Gu, X; Zhang, E; Park, M-A; Pereira, A M; Wang, S; Morrison, T; Li, C; Blenis, J; Gerbaudo, V H; Henske, E P; Yu, J J

    2014-05-15

    Lymphangioleiomyomatosis (LAM) is a female-predominant interstitial lung disease that can lead to respiratory failure. LAM cells typically have inactivating TSC2 mutations, leading to mTORC1 activation. The gender specificity of LAM suggests that estradiol contributes to disease development, yet the underlying pathogenic mechanisms are not completely understood. Using metabolomic profiling, we identified an estradiol-enhanced pentose phosphate pathway signature in Tsc2-deficient cells. Estradiol increased levels of cellular NADPH, decreased levels of reactive oxygen species, and enhanced cell survival under oxidative stress. Mechanistically, estradiol reactivated Akt in TSC2-deficient cells in vitro and in vivo, induced membrane translocation of glucose transporters (GLUT1 or GLUT4), and increased glucose uptake in an Akt-dependent manner. (18)F-FDG-PET imaging demonstrated enhanced glucose uptake in xenograft tumors of Tsc2-deficient cells from estradiol-treated mice. Expression array study identified estradiol-enhanced transcript levels of glucose-6-phosphate dehydrogenase (G6PD), the rate-limiting enzyme of the pentose phosphate pathway. Consistent with this, G6PD was abundant in xenograft tumors and lung metastatic lesions of Tsc2-deficient cells from estradiol-treated mice. Molecular depletion of G6PD attenuated estradiol-enhanced survival in vitro, and treatment with 6-aminonicotinamide, a competitive inhibitor of G6PD, reduced lung colonization of Tsc2-deficient cells. Collectively, these data indicate that estradiol promotes glucose metabolism in mTORC1 hyperactive cells through the pentose phosphate pathway via Akt reactivation and G6PD upregulation, thereby enhancing cell survival under oxidative stress. Interestingly, a strong correlation between estrogen exposure and G6PD was also found in breast cancer cells. Targeting the pentose phosphate pathway may have therapeutic benefit for LAM and possibly other hormonally dependent neoplasms.

  4. KNK437, abrogates hypoxia-induced radioresistance by dual targeting of the AKT and HIF-1{alpha} survival pathways

    Energy Technology Data Exchange (ETDEWEB)

    Oommen, Deepu, E-mail: oommen1978@gmail.com [Centre for Cancer Research and Cell Biology, Queen' s University Belfast, Belfast, Northern Ireland (United Kingdom); Prise, Kevin M. [Centre for Cancer Research and Cell Biology, Queen' s University Belfast, Belfast, Northern Ireland (United Kingdom)

    2012-05-11

    Highlights: Black-Right-Pointing-Pointer KNK437, a benzylidene lactam compound, is a novel radiosensitizer. Black-Right-Pointing-Pointer KNK437 inhibits AKT signaling and abrogates the accumulation of HIF-1{alpha} under hypoxia. Black-Right-Pointing-Pointer KNK437 abrogates hypoxia induced resistance to radiation. -- Abstract: KNK437 is a benzylidene lactam compound known to inhibit stress-induced synthesis of heat shock proteins (HSPs). HSPs promote radioresistance and play a major role in stabilizing hypoxia inducible factor-1{alpha} (HIF-1{alpha}). HIF-1{alpha} is widely responsible for tumor resistance to radiation under hypoxic conditions. We hypothesized that KNK437 sensitizes cancer cells to radiation and overrides hypoxia-induced radioresistance via destabilizing HIF-1{alpha}. Treatment of human cancer cells MDA-MB-231 and T98G with KNK437 sensitized them to ionizing radiation (IR). Surprisingly, IR did not induce HSPs in these cell lines. As hypothesized, KNK437 abrogated the accumulation of HIF-1{alpha} in hypoxic cells. However, there was no induction of HSPs under hypoxic conditions. Moreover, the proteosome inhibitor MG132 did not restore HIF-1{alpha} levels in KNK437-treated cells. This suggested that the absence of HIF-1{alpha} in hypoxic cells was not due to the enhanced protein degradation. HIF-1{alpha} is mainly regulated at the level of post-transcription and AKT is known to modulate the translation of HIF-1{alpha} mRNA. Interestingly, pre-treatment of cells with KNK437 inhibited AKT signaling. Furthermore, down regulation of AKT by siRNA abrogated HIF-1{alpha} levels under hypoxia. Interestingly, KNK437 reduced cell survival in hypoxic conditions and inhibited hypoxia-induced resistance to radiation. Taken together, these data suggest that KNK437 is an effective radiosensitizer that targets multiple pro-survival stress response pathways.

  5. 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

  6. Macrophage migration inhibitory factor induces phosphorylation of Mdm2 mediated by phosphatidylinositol 3-kinase/Akt kinase: Role of this pathway in decidual cell survival.

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    Costa, Adriana Fraga; Gomes, Sara Zago; Lorenzon-Ojea, Aline R; Martucci, Mariane; Faria, Miriam Rubio; Pinto, Décio Dos Santos; Oliveira, Sergio F; Ietta, Francesca; Paulesu, Luana; Bevilacqua, Estela

    2016-05-01

    The phosphatidylinositol 3-kinase (PI3K)/Akt pathway has an anti-apoptotic effect through several downstream targets, which includes activation of the transformed mouse 3T3 cell double-minute 2 (Mdm2) protein, its translocation to the nucleus and degradation of the tumor suppressor p53. We show that Mif, the Macrophage Migration Inhibitory Factor, an important cytokine at the maternal fetal interface in several species, triggers phosphorylation of Mdm2 protein in a PI3K/Akt-dependent manner, thereby preventing apoptosis in cultured mouse decidual cells. Inhibition of Akt and PI3K suppresses the pathway. Mif treatment also changes the nuclear translocation of p53 and interferes with the apoptotic fate of these cells when challenged with reactive oxygen species. In conclusion, an important mechanism has been found underlying decidual cell survival through Akt signaling pathway activated by Mif, suggesting a role for this cytokine in decidual homeostasis and in the integrity of the maternal-fetal barrier that is essential for successful gestation. PMID:27208405

  7. TGF-β inducible early gene 1 regulates osteoclast differentiation and survival by mediating the NFATc1, AKT, and MEK/ERK signaling pathways.

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    Muzaffer Cicek

    Full Text Available TGF-β Inducible Early Gene-1 (TIEG1 is a Krüppel-like transcription factor (KLF10 that was originally cloned from human osteoblasts as an early response gene to TGF-β treatment. As reported previously, TIEG1(-/- mice have decreased cortical bone thickness and vertebral bone volume and have increased spacing between the trabeculae in the femoral head relative to wildtype controls. Here, we have investigated the role of TIEG1 in osteoclasts to further determine their potential role in mediating this phenotype. We have found that TIEG1(-/- osteoclast precursors differentiated more slowly compared to wildtype precursors in vitro and high RANKL doses are able to overcome this defect. We also discovered that TIEG1(-/- precursors exhibit defective RANKL-induced phosphorylation and accumulation of NFATc1 and the NFATc1 target gene DC-STAMP. Higher RANKL concentrations reversed defective NFATc1 signaling and restored differentiation. After differentiation, wildtype osteoclasts underwent apoptosis more quickly than TIEG1(-/- osteoclasts. We observed increased AKT and MEK/ERK signaling pathway activation in TIEG1(-/- osteoclasts, consistent with the roles of these kinases in promoting osteoclast survival. Adenoviral delivery of TIEG1 (AdTIEG1 to TIEG1(-/- cells reversed the RANKL-induced NFATc1 signaling defect in TIEG1(-/- precursors and eliminated the differentiation and apoptosis defects. Suppression of TIEG1 with siRNA in wildtype cells reduced differentiation and NFATc1 activation. Together, these data provide evidence that TIEG1 controls osteoclast differentiation by reducing NFATc1 pathway activation and reduces osteoclast survival by suppressing AKT and MEK/ERK signaling.

  8. Curcumin Promotes Cell Cycle Arrest and Inhibits Survival of Human Renal Cancer Cells by Negative Modulation of the PI3K/AKT Signaling Pathway.

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    Zhang, Hao; Xu, Weili; Li, Baolin; Zhang, Kai; Wu, Yudong; Xu, Haidong; Wang, Junyong; Zhang, Jun; Fan, Rui; Wei, Jinxing

    2015-12-01

    Curcumin possesses anti-cancer effects. In the current study, we tested the effect of curcumin on cell proliferation, viability, apoptosis, cell cycle phases, and activation of the PI3K/Akt pathway in the renal cell carcinoma (RCC) cell line RCC-949. We observed that cell proliferation and viability were markedly inhibited by curcumin, while cell apoptosis was promoted. The latter effect was associated with increased expression of Bcl-2 and diminished expression of Bax (both: mRNA and protein). The cells treated with curcumin increasingly went into cell cycle arrest, which was likely mediated by diminished expression of cyclin B1, as seen in curcumin-treated cells. In addition, curcumin decreased activation of the PI3K/AKT signaling pathway. In conclusion, our results demonstrate that curcumin exerts anti-cancer effects by negative modulation of the PI3K/AKT signaling pathway and may represent a promising new drug to treat RCC. PMID:27259310

  9. Mitochondrial genome depletion in human liver cells abolishes bile acid-induced apoptosis: role of the Akt/mTOR survival pathway and Bcl-2 family proteins.

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    Marin, Jose J G; Hernandez, Alicia; Revuelta, Isabel E; Gonzalez-Sanchez, Ester; Gonzalez-Buitrago, Jose M; Perez, Maria J

    2013-08-01

    Acute accumulation of bile acids in hepatocytes may cause cell death. However, during long-term exposure due to prolonged cholestasis, hepatocytes may develop a certain degree of chemoresistance to these compounds. Because mitochondrial adaptation to persistent oxidative stress may be involved in this process, here we have investigated the effects of complete mitochondrial genome depletion on the response to bile acid-induced hepatocellular injury. A subline (Rho) of human hepatoma SK-Hep-1 cells totally depleted of mitochondrial DNA (mtDNA) was obtained, and bile acid-induced concentration-dependent activation of apoptosis/necrosis and survival signaling pathways was studied. In the absence of changes in intracellular ATP content, Rho cells were highly resistant to bile acid-induced apoptosis and partially resistant to bile acid-induced necrosis. In Rho cells, both basal and bile acid-induced generation of reactive oxygen species (ROS), such as hydrogen peroxide and superoxide anion, was decreased. Bile acid-induced proapoptotic signals were also decreased, as evidenced by a reduction in the expression ratios Bax-α/Bcl-2, Bcl-xS/Bcl-2, and Bcl-xS/Bcl-xL. This was mainly due to a downregulation of Bax-α and Bcl-xS. Moreover, in these cells the Akt/mTOR pathway was constitutively activated in a ROS-independent manner and remained similarly activated in the presence of bile acid treatment. In contrast, ERK1/2 activation was constitutively reduced and was not activated by incubation with bile acids. In conclusion, these results suggest that impaired mitochondrial function associated with mtDNA alterations, which may occur in liver cells during prolonged cholestasis, may activate mechanisms of cell survival accounting for an enhanced resistance of hepatocytes to bile acid-induced apoptosis. PMID:23597504

  10. Targeting the AKT pathway: Repositioning HIV protease inhibitors as radiosensitizers

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    Jayant S Goda

    2016-01-01

    Full Text Available Cellular resistance in tumour cells to different therapeutic approaches has been a limiting factor in the curative treatment of cancer. Resistance to therapeutic radiation is a common phenomenon which significantly reduces treatment options and impacts survival. One of the mechanisms of acquiring resistance to ionizing radiation is the overexpression or activation of various oncogenes like the EGFR (epidermal growth factor receptor, RAS (rat sarcoma oncogene or loss of PTEN (phosphatase and tensin homologue which in turn activates the phosphatidyl inositol 3-kinase/protein kinase B (PI3-K/AKT pathway responsible for radiation resistance in various tumours. Blocking the pathway enhances the radiation response both in vitro and in vivo. Due to the differential activation of this pathway (constitutively activated in tumour cells and not in the normal host cells, it is an excellent candidate target for molecular targeted therapy to enhance radiation sensitivity. In this regard, HIV protease inhibitors (HPIs known to interfere with PI3-K/AKT signaling in tumour cells, have been shown to sensitize various tumour cells to radiation both in vitro and in vivo. As a result, HPIs are now being investigated as possible radiosensitizers along with various chemotherapeutic drugs. This review describes the mechanisms by which PI3-K/AKT pathway causes radioresistance and the role of HIV protease inhibitors especially nelfinavir as a potential candidate drug to target the AKT pathway for overcoming radioresistance and its use in various clinical trials for different malignancies.

  11. Targeting the AKT pathway: Repositioning HIV protease inhibitors as radiosensitizers.

    Science.gov (United States)

    Goda, Jayant S; Pachpor, Tejaswini; Basu, Trinanjan; Chopra, Supriya; Gota, Vikram

    2016-02-01

    Cellular resistance in tumour cells to different therapeutic approaches has been a limiting factor in the curative treatment of cancer. Resistance to therapeutic radiation is a common phenomenon which significantly reduces treatment options and impacts survival. One of the mechanisms of acquiring resistance to ionizing radiation is the overexpression or activation of various oncogenes like the EGFR (epidermal growth factor receptor), RAS (rat sarcoma) oncogene or loss of PTEN (phosphatase and tensin homologue) which in turn activates the phosphatidyl inositol 3-kinase/protein kinase B (PI3-K)/AKT pathway responsible for radiation resistance in various tumours. Blocking the pathway enhances the radiation response both in vitro and in vivo. Due to the differential activation of this pathway (constitutively activated in tumour cells and not in the normal host cells), it is an excellent candidate target for molecular targeted therapy to enhance radiation sensitivity. In this regard, HIV protease inhibitors (HPIs) known to interfere with PI3-K/AKT signaling in tumour cells, have been shown to sensitize various tumour cells to radiation both in vitro and in vivo. As a result, HPIs are now being investigated as possible radiosensitizers along with various chemotherapeutic drugs. This review describes the mechanisms by which PI3-K/AKT pathway causes radioresistance and the role of HIV protease inhibitors especially nelfinavir as a potential candidate drug to target the AKT pathway for overcoming radioresistance and its use in various clinical trials for different malignancies.

  12. PI3K/Akt signalling pathway and cancer.

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

    2004-04-01

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

  13. Somatic Copy Number Abnormalities and Mutations in PI3K/AKT/mTOR Pathway Have Prognostic Significance for Overall Survival in Platinum Treated Locally Advanced or Metastatic Urothelial Tumors.

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    Joaquim Bellmunt

    Full Text Available An integrative analysis was conducted to identify genomic alterations at a pathway level that could predict overall survival (OS in patients with advanced urothelial carcinoma (UC treated with platinum-based chemotherapy.DNA and RNA were extracted from 103 formalin-fixed paraffin embedded (FFPE invasive high-grade UC samples and were screened for mutations, copy number variation (CNV and gene expression analysis. Clinical data were available from 85 cases. Mutations were analyzed by mass-spectrometry based on genotyping platform (Oncomap 3 and genomic imbalances were detected by comparative genomic hybridization (CGH analysis. Regions with threshold of log2 ratio ≥0.4, or ≤0.6 were defined as either having copy number gain or loss and significantly recurrent CNV across the set of samples were determined using a GISTIC analysis. Expression analysis on selected relevant UC genes was conducted using Nanostring. To define the co-occurrence pattern of mutations and CNV, we grouped genomic events into 5 core signal transduction pathways: 1 TP53 pathway, 2 RTK/RAS/RAF pathway, 3 PI3K/AKT/mTOR pathway, 4 WNT/CTNNB1, 5 RB1 pathway. Cox regression was used to assess pathways abnormalities with survival outcomes.35 samples (41% harbored mutations on at least one gene: TP53 (16%, PIK3CA (9%, FGFR3 (2%, HRAS/KRAS (5%, and CTNNB1 (1%. 66% of patients had some sort of CNV. PIK3CA/AKT/mTOR pathway alteration (mutations+CNV had the greatest impact on OS (p=0.055. At a gene level, overexpression of CTNNB1 (p=0.0008 and PIK3CA (p=0.02 were associated with shorter OS. Mutational status on PIK3CA was not associated with survival. Among other individually found genomic alterations, TP53 mutations (p=0.07, mTOR gain (p=0.07 and PTEN overexpression (p=0.08 have a marginally significant negative impact on OS.Our study suggests that targeted therapies focusing on the PIK3CA/AKT/mTOR pathway genomic alterations can generate the greatest impact in the overall patient

  14. Cardioprotective effects of the novel Na+/H+ exchanger-1 inhibitor KR-32560 in a perfused rat heart model of global ischemia and reperfusion: Involvement of the Akt-GSK-3beta cell survival pathway and antioxidant enzyme.

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    Jung, In-Sang; Lee, Sung-Hun; Yang, Min-Kyu; Park, Jung-Woo; Yi, Kyu-Yang; Yoo, Sung-Eun; Kwon, Suk-Hyung; Chung, Hun-Jong; Choi, Wahn-Soo; Shin, Hwa-Sup

    2010-08-01

    To investigate the cardioprotective effects and mechanism of action of KR-32560 {[5-(2-methoxy-5-fluorophenyl)furan-2-ylcarbonyl]guanidine}, a newly synthesized NHE-1 inhibitor, we evaluated the effects of KR-32560 on cardiac function in a rat model of ischemia/reperfusion (I/R)-induced heart injury as well as the role antioxidant enzymes and pro-survival proteins play these observed effects. In isolated rat hearts subjected to 25 min of global ischemia followed by 30 min of reperfusion, KR-32560 (3 and 10 microM) significantly reversed the I/Rinduced decrease in left ventricular developed pressure and increase in left ventricular enddiastolic pressure. In rat hearts reperfused for 30 min, KR-32560 (10 microM) significantly decreased the malondialdehyde content while increasing the activities of both glutathione peroxidase and catalase, two important antioxidant enzymes. Western blotting analysis of left ventricles subjected to I/R showed that KR-32560 significantly increased phosphorylation of both Akt and GSK-3beta in a dose-dependent manner, with no effect on the phosphorylation of eNOS. These results suggest that KR-32560 exerts potent cardioprotective effects against I/Rinduced rat heart injury and that its mechanism involves antioxidant enzymes and the Akt-GSK-3beta cell survival pathway.

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

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    Osaki, M; Oshimura, M; Ito, H

    2004-11-01

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

  16. Apigenin Reduces Survival of Choriocarcinoma Cells by Inducing Apoptosis via the PI3K/AKT and ERK1/2 MAPK Pathways.

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    Lim, Whasun; Park, Sunwoo; Bazer, Fuller W; Song, Gwonhwa

    2016-12-01

    Apigenin is a flavonoid found in parsley, onions, oranges, tea, chamomile, wheat, and sprouts. It has a variety of biological properties including anti-oxidant, anti-mutagenic, anti-carcinogenic, anti-inflammatory, anti-proliferative, and anti-spasmodic effects. Based on epidemiological and case-control studies, apigenin is regarded as a novel chemotherapeutic agent against various cancer types. However, little is known about the effects of apigenin on choriocarcinoma cells. Therefore, we investigated the anti-cancer effects of apigenin on choriocarcinoma cells (JAR and JEG3) in the present study. Apigenin reduced viability and migratory properties, increased apoptosis, and suppressed mitochondrial membrane potential in both the JAR and JEG3 cells. In addition, apigenin predominantly decreased phosphorylation of AKT, P70RSK, and S6 whereas the phosphorylation of ERK1/2 and P90RSK was increased by apigenin treatment of JAR and JEG3 cells in a dose-dependent manner. Moreover, treatment of JAR and JEG3 cells with both apigenin and pharmacological inhibitors of PI3K/AKT (LY294002) and ERK1/2 (U0126) revealed synergistic anti-proliferative effects. Collectively, these results indicated that the apigenin is an invaluable chemopreventive agent that inhibits progression and metastasis of choriocarcinoma cells through regulation of PI3K/AKT and ERK1/2 MAPK signal transduction mechanism. J. Cell. Physiol. 231: 2690-2699, 2016. © 2016 Wiley Periodicals, Inc. PMID:26970256

  17. AKT signaling mediates IGF-I survival actions on otic neural progenitors.

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    Maria R Aburto

    Full Text Available BACKGROUND: Otic neurons and sensory cells derive from common progenitors whose transition into mature cells requires the coordination of cell survival, proliferation and differentiation programmes. Neurotrophic support and survival of post-mitotic otic neurons have been intensively studied, but the bases underlying the regulation of programmed cell death in immature proliferative otic neuroblasts remains poorly understood. The protein kinase AKT acts as a node, playing a critical role in controlling cell survival and cell cycle progression. AKT is activated by trophic factors, including insulin-like growth factor I (IGF-I, through the generation of the lipidic second messenger phosphatidylinositol 3-phosphate by phosphatidylinositol 3-kinase (PI3K. Here we have investigated the role of IGF-dependent activation of the PI3K-AKT pathway in maintenance of otic neuroblasts. METHODOLOGY/PRINCIPAL FINDINGS: By using a combination of organotypic cultures of chicken (Gallus gallus otic vesicles and acoustic-vestibular ganglia, Western blotting, immunohistochemistry and in situ hybridization, we show that IGF-I-activation of AKT protects neural progenitors from programmed cell death. IGF-I maintains otic neuroblasts in an undifferentiated and proliferative state, which is characterised by the upregulation of the forkhead box M1 (FoxM1 transcription factor. By contrast, our results indicate that post-mitotic p27(Kip-positive neurons become IGF-I independent as they extend their neuronal processes. Neurons gradually reduce their expression of the Igf1r, while they increase that of the neurotrophin receptor, TrkC. CONCLUSIONS/SIGNIFICANCE: Proliferative otic neuroblasts are dependent on the activation of the PI3K-AKT pathway by IGF-I for survival during the otic neuronal progenitor phase of early inner ear development.

  18. TNF-alpha stimulates Akt by a distinct aPKC-dependent pathway in premalignant keratinocytes

    DEFF Research Database (Denmark)

    Faurschou, A.; Gniadecki, R.

    2008-01-01

    , ERK1/2 and p38. The specific peptide blocking the activity of the atypical protein kinase C (aPKC) species zeta and iota/lambda abrogated the effects of TNF-alpha on Akt and ERK1/2 but increased the activation of p38. The TNF-alpha-dependent phosphorylation of Akt-ERK1/2 was slightly decreased by NF......B- and OH-dependent pathway resulting in the activation of survival and mitogenic pathways mediated by Akt and ERK1/2, and a signalling pathway conveyed by p38 that contributes to Akt activation but is suppressed by aPKC. Our data may be utilized in the development of more selective anti...... kappaB inhibition and in the presence of p38 blockers. Akt/ERK signalling but not p38 activation was abolished in the presence of the iron chelator desferroxamine that blocks formation of hydroxyl ( OH) radicals. Thus, the TNF-alpha signalling in keratinocytes seems to bifurcate into an aPKC-, NFk...

  19. COX-2 activation is associated with Akt phosphorylation and poor survival in ER-negative, HER2-positive breast cancer

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    Goodman Julie E

    2010-11-01

    Full Text Available Abstract Background Inducible cyclooxgenase-2 (COX-2 is commonly overexpressed in breast tumors and is a target for cancer therapy. Here, we studied the association of COX-2 with breast cancer survival and how this association is influenced by tumor estrogen and HER2 receptor status and Akt pathway activation. Methods Tumor COX-2, HER2 and estrogen receptor α (ER expression and phosphorylation of Akt, BAD, and caspase-9 were analyzed immunohistochemically in 248 cases of breast cancer. Spearman's correlation and multivariable logistic regression analyses were used to examine the relationship between COX-2 and tumor characteristics. Kaplan-Meier survival and multivariable Cox proportional hazards regression analyses were used to examine the relationship between COX-2 and disease-specific survival. Results COX-2 was significantly associated with breast cancer outcome in ER-negative [Hazard ratio (HR = 2.72; 95% confidence interval (CI, 1.36-5.41; comparing high versus low COX-2] and HER2 overexpressing breast cancer (HR = 2.84; 95% CI, 1.07-7.52. However, the hazard of poor survival associated with increased COX-2 was highest among patients who were both ER-negative and HER2-positive (HR = 5.95; 95% CI, 1.01-34.9. Notably, COX-2 expression in the ER-negative and HER2-positive tumors correlated significantly with increased phosphorylation of Akt and of the two Akt targets, BAD at Ser136 and caspase-9 at Ser196. Conclusions Up-regulation of COX-2 in ER-negative and HER2-positive breast tumors is associated with Akt pathway activation and is a marker of poor outcome. The findings suggest that COX-2-specific inhibitors and inhibitors of the Akt pathway may act synergistically as anticancer drugs in the ER-negative and HER2-positive breast cancer subtype.

  20. 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.

  1. Bimatoprost protects retinal neuronal damage via Akt pathway.

    Science.gov (United States)

    Takano, Norihito; Tsuruma, Kazuhiro; Ohno, Yuta; Shimazawa, Masamitsu; Hara, Hideaki

    2013-02-28

    Worldwide, prostaglandin analogs, such as bimatoprost, have become the major therapeutic class for medical treatment of glaucoma because of their efficacy and generally well tolerated systemic safety profile. However, the detailed mechanism of the direct action of bimatoprost on retinal ganglion cells (RGC) has rarely been understood. Thus, in this study, we elucidated the mechanism of the protective effects of bimatoprost on RGC against oxidative stress. To examine the protective effects of bimatoprost, cultured RGC with various concentrations of bimatoprost (in both free acid and amide form) were exposed to l-buthionin-(S,R)-sulfoximine (BSO) plus glutamate or serum depletion in vitro and intravitreal injection of N-methyl-D-aspartate (NMDA) was used to induce retinal damage in vivo. To elucidate the protective mechanism of bimatoprost, we used western blot analysis to investigate the phosphorylation of Akt and extracellular signal-regulated kinase (ERK). Bimatoprost significantly reduced BSO plus glutamate- and serum deprivation-induced death in concentration-dependent manners. Bimatoprost induced activation of Akt and ERK, and a phosphatidylinositol 3-kinase inhibitor, LY294002, attenuated the protective effect of bimatoprost. On the other hand, a mitogen-activated protein kinase kinase inhibitor, U0126, exhibited protective effect unexpectedly. Moreover, ERK was more phosphorylated by attenuation of Akt activity in cultured RGC. In an in vivo study, bimatoprost reduced NMDA-induced RGC death. Taken together, these findings indicate that bimatoprost has protective effects on in vitro and in vivo retinal damage, suggesting that the mechanism underlying may be via the Akt pathway, which may modulate the ERK pathway.

  2. Phenylbutyric acid induces the cellular senescence through an Akt/p21{sup WAF1} signaling pathway

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    Kim, Hag Dong [Laboratory of Biochemistry, School of Life Sciences and Biotechnology, and BioInstitute, Korea University, Seoul 136-701 (Korea, Republic of); Jang, Chang-Young [Research Center for Cell Fate Control, College of Pharmacy, Sookmyung Women' s University, Seoul 140-742 (Korea, Republic of); Choe, Jeong Min [Laboratory of Biochemistry, School of Life Sciences and Biotechnology, and BioInstitute, Korea University, Seoul 136-701 (Korea, Republic of); Department of Biochemistry, Korea University College of Medicine, Seoul 136-705 (Korea, Republic of); Korean Institute of Molecular Medicine and Nutrition, Seoul 136-705 (Korea, Republic of); Sohn, Jeongwon, E-mail: biojs@korea.ac.kr [Department of Biochemistry, Korea University College of Medicine, Seoul 136-705 (Korea, Republic of); Korean Institute of Molecular Medicine and Nutrition, Seoul 136-705 (Korea, Republic of); Kim, Joon, E-mail: joonkim@korea.ac.kr [Laboratory of Biochemistry, School of Life Sciences and Biotechnology, and BioInstitute, Korea University, Seoul 136-701 (Korea, Republic of)

    2012-06-01

    Highlights: Black-Right-Pointing-Pointer Phenylbutyric acid induces cellular senescence. Black-Right-Pointing-Pointer Phenylbutyric acid activates Akt kinase. Black-Right-Pointing-Pointer The knockdown of PERK also can induce cellular senescence. Black-Right-Pointing-Pointer Akt/p21{sup WAF1} pathway activates in PERK knockdown induced cellular senescence. -- Abstract: It has been well known that three sentinel proteins - PERK, ATF6 and IRE1 - initiate the unfolded protein response (UPR) in the presence of misfolded or unfolded proteins in the ER. Recent studies have demonstrated that upregulation of UPR in cancer cells is required to survive and proliferate. Here, we showed that long exposure to 4-phenylbutyric acid (PBA), a chemical chaperone that can reduce retention of unfolded and misfolded proteins in ER, induced cellular senescence in cancer cells such as MCF7 and HT1080. In addition, we found that treatment with PBA activates Akt, which results in p21{sup WAF1} induction. Interestingly, the depletion of PERK but not ATF6 and IRE1 also induces cellular senescence, which was rescued by additional depletion of Akt. This suggests that Akt pathway is downstream of PERK in PBA induced cellular senescence. Taken together, these results show that PBA induces cellular senescence via activation of the Akt/p21{sup WAF1} pathway by PERK inhibition.

  3. Propofol pretreatment attenuates lipopolysaccharide-induced acute lung injury in rats by activating the phosphoinositide-3-kinase/Akt pathway

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, L.L. [Department of Anesthesiology, The Affiliated Hospital of Xuzhou Medical College, Xuzhou, Jiangsu Province (China); Hu, G.C. [Department of Pharmacology, College of Medicine, University of Illinois at Chicago, Chicago, IL (United States); Zhu, S.S. [Department of Anesthesiology, The Affiliated Hospital of Xuzhou Medical College, Xuzhou, Jiangsu Province (China); Li, J.F. [Department of Anesthesiology, Tengzhou Central People' s Hospital, Liaocheng, Shandong Province (China); Liu, G.J. [Department of Anesthesiology, The Affiliated Hospital of Xuzhou Medical College, Xuzhou, Jiangsu Province (China)

    2014-10-14

    The aim of this study was to investigate the effect of propofol pretreatment on lipopolysaccharide (LPS)-induced acute lung injury (ALI) and the role of the phosphoinositide-3-kinase/protein kinase B (PI3K/Akt) pathway in this procedure. Survival was determined 48 h after LPS injection. At 1 h after LPS challenge, the lung wet- to dry-weight ratio was examined, and concentrations of protein, tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) in bronchoalveolar lavage fluid (BALF) were determined using the bicinchoninic acid method or ELISA. Lung injury was assayed via lung histological examination. PI3K and p-Akt expression levels in the lung tissue were determined by Western blotting. Propofol pretreatment prolonged survival, decreased the concentrations of protein, TNF-α, and IL-6 in BALF, attenuated ALI, and increased PI3K and p-Akt expression in the lung tissue of LPS-challenged rats, whereas treatment with wortmannin, a PI3K/Akt pathway specific inhibitor, blunted this effect. Our study indicates that propofol pretreatment attenuated LPS-induced ALI, partly by activation of the PI3K/Akt pathway.

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

    Science.gov (United States)

    Maurya, Akhilendra Kumar; Vinayak, Manjula

    2016-01-01

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

  5. Genomically amplified Akt3 activates DNA repair pathway and promotes glioma progression.

    Science.gov (United States)

    Turner, Kristen M; Sun, Youting; Ji, Ping; Granberg, Kirsi J; Bernard, Brady; Hu, Limei; Cogdell, David E; Zhou, Xinhui; Yli-Harja, Olli; Nykter, Matti; Shmulevich, Ilya; Yung, W K Alfred; Fuller, Gregory N; Zhang, Wei

    2015-03-17

    Akt is a robust oncogene that plays key roles in the development and progression of many cancers, including glioma. We evaluated the differential propensities of the Akt isoforms toward progression in the well-characterized RCAS/Ntv-a mouse model of PDGFB-driven low grade glioma. A constitutively active myristoylated form of Akt1 did not induce high-grade glioma (HGG). In stark contrast, Akt2 and Akt3 showed strong progression potential with 78% and 97% of tumors diagnosed as HGG, respectively. We further revealed that significant variations in polarity and hydropathy values among the Akt isoforms in both the pleckstrin homology domain (P domain) and regulatory domain (R domain) were critical in mediating glioma progression. Gene expression profiles from representative Akt-derived tumors indicated dominant and distinct roles for Akt3, consisting primarily of DNA repair pathways. TCGA data from human GBM closely reflected the DNA repair function, as Akt3 was significantly correlated with a 76-gene signature DNA repair panel. Consistently, compared with Akt1 and Akt2 overexpression models, Akt3-expressing human GBM cells had enhanced activation of DNA repair proteins, leading to increased DNA repair and subsequent resistance to radiation and temozolomide. Given the wide range of Akt3-amplified cancers, Akt3 may represent a key resistance factor.

  6. mTOR Promotes Survival and Astrocytic Characteristics Induced by Pten/Akt Signaling in Glioblastoma

    Directory of Open Access Journals (Sweden)

    Xiaoyi Hu

    2005-04-01

    Full Text Available Combined activation of Ras and Akt leads to the formation of astrocytic glioblastoma multiforme (GBM in mice. In human GBMs, AKT is not mutated but is activated in approximately 70% of these tumors, in association with loss of PTEN and/or activation of receptor tyrosine kinases. Mechanistic justification for the therapeutic blockade of targets downstream of AKT, such as mTOR, in these cancers requires demonstration that the oncogenic effect of PTEN loss is through elevated AKT activity. We demonstrate here that loss of Pten is similar to Akt activation in the context of glioma formation in mice. We further delineate the role of mTOR activity downstream of Akt in the maintenance of Akt+KRas-induced GBMs. Blockade of mTOR results in regional apoptosis in these tumors and conversion in the character of surviving tumor cells from astrocytoma to oligodendroglioma. These data suggest that mTOR activity is required for the survival of some cells within these GBMs, and mTOR appears required for the maintenance of astrocytic character in the surviving cells. Furthermore, our study provides the first example of conversion between two distinct tumor types usually thought of as belonging to specific lineages, and provides evidence for signal transduction-mediated transdifferentiation between glioma subtypes.

  7. Inhibition of HSP27 alone or in combination with pAKT inhibition as therapeutic approaches to target SPARC-induced glioma cell survival

    Directory of Open Access Journals (Sweden)

    Schultz Chad R

    2012-04-01

    Full Text Available Abstract Background The current treatment regimen for glioma patients is surgery, followed by radiation therapy plus temozolomide (TMZ, followed by 6 months of adjuvant TMZ. Despite this aggressive treatment regimen, the overall survival of all surgically treated GBM patients remains dismal, and additional or different therapies are required. Depending on the cancer type, SPARC has been proposed both as a therapeutic target and as a therapeutic agent. In glioma, SPARC promotes invasion via upregulation of the p38 MAPK/MAPKAPK2/HSP27 signaling pathway, and promotes tumor cell survival by upregulating pAKT. As HSP27 and AKT interact to regulate the activity of each other, we determined whether inhibition of HSP27 was better than targeting SPARC as a therapeutic approach to inhibit both SPARC-induced glioma cell invasion and survival. Results Our studies found the following. 1 SPARC increases the expression of tumor cell pro-survival and pro-death protein signaling in balance, and, as a net result, tumor cell survival remains unchanged. 2 Suppressing SPARC increases tumor cell survival, indicating it is not a good therapeutic target. 3 Suppressing HSP27 decreases tumor cell survival in all gliomas, but is more effective in SPARC-expressing tumor cells due to the removal of HSP27 inhibition of SPARC-induced pro-apoptotic signaling. 4 Suppressing total AKT1/2 paradoxically enhanced tumor cell survival, indicating that AKT1 or 2 are poor therapeutic targets. 5 However, inhibiting pAKT suppresses tumor cell survival. 6 Inhibiting both HSP27 and pAKT synergistically decreases tumor cell survival. 7 There appears to be a complex feedback system between SPARC, HSP27, and AKT. 8 This interaction is likely influenced by PTEN status. With respect to chemosensitization, we found the following. 1 SPARC enhances pro-apoptotic signaling in cells exposed to TMZ. 2 Despite this enhanced signaling, SPARC protects cells against TMZ. 3 This protection can be reduced

  8. Clinical prognostic significance and pro-metastatic activity of RANK/RANKL via the AKT pathway in endometrial cancer.

    Science.gov (United States)

    Wang, Jing; Liu, Yao; Wang, Lihua; Sun, Xiao; Wang, Yudong

    2016-02-01

    RANK/RANKL plays a key role in metastasis of certain malignant tumors, which makes it a promising target for developing novel therapeutic strategies for cancer. However, the prognostic value and pro-metastatic activity of RANK in endometrial cancer (EC) remain to be determined. Thus, the present study investigated the effect of RANK on the prognosis of EC patients, as well as the pro-metastatic activity of EC cells. The results indicated that those with high expression of RANK showed decreased overall survival and progression-free survival. Statistical analysis revealed the positive correlations between RANK/RANKL expression and metastasis-related factors. Additionally, RANK/RANKL significantly promoted cell migration/invasion via activating AKT/β-catenin/Snail pathway in vitro. However, RANK/RANKL-induced AKT activation could be suppressed after osteoprotegerin (OPG) treatment. Furthermore, the combination of medroxyprogesterone acetate (MPA) and RANKL could in turn attenuate the effect of RANKL alone. Similarly, MPA could partially inhibit the RANK-induced metastasis in an orthotopic mouse model via suppressing AKT/β-catenin/Snail pathway. Therefore, therapeutic inhibition of MPA in RANK/RANKL-induced metastasis was mediated by AKT/β-catenin/Snail pathway both in vitro and in vivo, suggesting a potential target of RANK for gene-based therapy for EC. PMID:26734994

  9. MicroRNA-184 inhibits neuroblastoma cell survival through targeting the serine/threonine kinase AKT2

    Directory of Open Access Journals (Sweden)

    Murphy Derek M

    2010-04-01

    Full Text Available Abstract Background Neuroblastoma is a paediatric cancer of the sympathetic nervous system. The single most important genetic indicator of poor clinical outcome is amplification of the MYCN transcription factor. One of many down-stream MYCN targets is miR-184, which is either directly or indirectly repressed by this transcription factor, possibly due to its pro-apoptotic effects when ectopically over-expressed in neuroblastoma cells. The purpose of this study was to elucidate the molecular mechanism by which miR-184 conveys pro-apoptotic effects. Results We demonstrate that the knock-down of endogenous miR-184 has the opposite effect of ectopic up-regulation, leading to enhanced neuroblastoma cell numbers. As a mechanism of how miR-184 causes apoptosis when over-expressed, and increased cell numbers when inhibited, we demonstrate direct targeting and degradation of AKT2, a major downstream effector of the phosphatidylinositol 3-kinase (PI3K pathway, one of the most potent pro-survival pathways in cancer. The pro-apoptotic effects of miR-184 ectopic over-expression in neuroblastoma cell lines is reproduced by siRNA inhibition of AKT2, while a positive effect on cell numbers similar to that obtained by the knock-down of endogenous miR-184 can be achieved by ectopic up-regulation of AKT2. Moreover, co-transfection of miR-184 with an AKT2 expression vector lacking the miR-184 target site in the 3'UTR rescues cells from the pro-apoptotic effects of miR-184. Conclusions MYCN contributes to tumorigenesis, in part, by repressing miR-184, leading to increased levels of AKT2, a direct target of miR-184. Thus, two important genes with positive effects on cell growth and survival, MYCN and AKT2, can be linked into a common genetic pathway through the actions of miR-184. As an inhibitor of AKT2, miR-184 could be of potential benefit in miRNA mediated therapeutics of MYCN amplified neuroblastoma and other forms of cancer.

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

    Directory of Open Access Journals (Sweden)

    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.

  11. SG2NA enhances cancer cell survival by stabilizing DJ-1 and thus activating Akt

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    Tanti, Goutam Kumar, E-mail: goutamjnu@hotmail.com; Pandey, Shweta; Goswami, Shyamal K.

    2015-08-07

    SG2NA in association with striatin and zinedin forms a striatin family of WD-40 repeat proteins. This family of proteins functions as scaffold in different signal transduction pathways. They also act as a regulatory subunit of protein phosphatase 2A. We have shown that SG2NA which evolved first in the metazoan evolution among the striatin family members expresses different isoforms generated out of alternative splicing. We have also shown that SG2NA protects cells from oxidative stress by recruiting DJ-1 and Akt to mitochondria and membrane in the post-mitotic neuronal cells. DJ-1 is both cancer and Parkinson's disease related protein. In the present study we have shown that SG2NA protects DJ-1 from proteasomal degradation in cancer cells. Hence, downregulation of SG2NA reduces DJ-1/Akt colocalization in cancer cells resulting in the reduction of anchorage dependent and independent growth. Thus SG2NA enhances cancer cell survival. Reactive oxygen species enhances SG2NA, DJ-1 and Akt trimerization. Removal of the reactive oxygen species by N-acetyl-cysteine thus reduces cancer cell growth. - Highlights: • Reactive oxygen species (ROS) play potential role in cancer cell proliferation. • It enhances the association between DJ-1 and Akt mediated by SG2NA. • In cancer cells SG2NA stabilizes DJ-1 by inhibiting it from proteosomal degradation. • DJ-1 then activates Akt and cancer cells get their property of enhanced proliferation by sustained activation of Akt. • Further study on this field could lead to new target for cancer therapy.

  12. Molecular Genetics of the PI3K-AKT-mTOR Pathway in Genodermatoses: Diagnostic Implications and Treatment Opportunities.

    Science.gov (United States)

    Vahidnezhad, Hassan; Yousse An, Leila; Uitto, Jouni

    2016-01-01

    A number of critical signaling pathways are required for homeostatic regulation of cell survival, differentiation, and proliferation during organogenesis. One of them is the PI3K-AKT-mTOR pathway consisting of a cascade of inhibitor/activator molecules. Recently, a number of heritable diseases with skin involvement, manifesting particularly with tissue overgrowth, have been shown to result from mutations in the genes in the PI3K-AKT-mTOR and interacting intracellular pathways. Many of these conditions represent an overlapping spectrum of phenotypic manifestations forming a basis for novel, unifying classifications. Identification of the mutant genes and specific mutations in these patients has implications for diagnostics and genetic counseling and provides a rational basis for the development of novel treatment modalities for this currently intractable group of disorders.

  13. Juglanthraquinone C Induces Intracellular ROS Increase and Apoptosis by Activating the Akt/Foxo Signal Pathway in HCC Cells

    Directory of Open Access Journals (Sweden)

    Ya-Qin Hou

    2016-01-01

    Full Text Available Juglanthraquinone C (JC, a naturally occurring anthraquinone extracted from Juglans mandshurica, could induce apoptosis of cancer cells. This study aims to investigate the detailed cytotoxicity mechanism of JC in HepG2 and BEL-7402 cells. The Affymetrix HG-U133 Plus 2.0 arrays were first used to analyze the mRNA expression exposed to JC or DMSO in HepG2 cells. Consistent with the previous results, the data indicated that JC could induce apoptosis and hyperactivated Akt. The Western blot analysis further revealed that Akt, a well-known survival protein, was strongly activated in HepG2 and BEL-7402 cells. Furthermore, an obvious inhibitory effect on JC-induced apoptosis was observed when the Akt levels were decreased, while the overexpression of constitutively active mutant Akt greatly accelerated JC-induced apoptosis. The subsequent results suggested that JC treatment suppressed nuclear localization and increased phosphorylated levels of Foxo3a, and the overexpression of Foxo3a abrogated JC-induced apoptosis. Most importantly, the inactivation of Foxo3a induced by JC further led to an increase of intracellular ROS levels by suppressing ROS scavenging enzymes, and the antioxidant N-acetyl-L-cysteine and catalase successfully decreased JC-induced apoptosis. Collectively, this study demonstrated that JC induced the apoptosis of hepatocellular carcinoma (HCC cells by activating Akt/Foxo signaling pathway and increasing intracellular ROS levels.

  14. Juglanthraquinone C Induces Intracellular ROS Increase and Apoptosis by Activating the Akt/Foxo Signal Pathway in HCC Cells

    Science.gov (United States)

    2016-01-01

    Juglanthraquinone C (JC), a naturally occurring anthraquinone extracted from Juglans mandshurica, could induce apoptosis of cancer cells. This study aims to investigate the detailed cytotoxicity mechanism of JC in HepG2 and BEL-7402 cells. The Affymetrix HG-U133 Plus 2.0 arrays were first used to analyze the mRNA expression exposed to JC or DMSO in HepG2 cells. Consistent with the previous results, the data indicated that JC could induce apoptosis and hyperactivated Akt. The Western blot analysis further revealed that Akt, a well-known survival protein, was strongly activated in HepG2 and BEL-7402 cells. Furthermore, an obvious inhibitory effect on JC-induced apoptosis was observed when the Akt levels were decreased, while the overexpression of constitutively active mutant Akt greatly accelerated JC-induced apoptosis. The subsequent results suggested that JC treatment suppressed nuclear localization and increased phosphorylated levels of Foxo3a, and the overexpression of Foxo3a abrogated JC-induced apoptosis. Most importantly, the inactivation of Foxo3a induced by JC further led to an increase of intracellular ROS levels by suppressing ROS scavenging enzymes, and the antioxidant N-acetyl-L-cysteine and catalase successfully decreased JC-induced apoptosis. Collectively, this study demonstrated that JC induced the apoptosis of hepatocellular carcinoma (HCC) cells by activating Akt/Foxo signaling pathway and increasing intracellular ROS levels. PMID:26682007

  15. The Akt1/IL-6/STAT3 pathway regulates growth of lung tumor initiating cells.

    Science.gov (United States)

    Malanga, Donatella; De Marco, Carmela; Guerriero, Ilaria; Colelli, Fabiana; Rinaldo, Nicola; Scrima, Marianna; Mirante, Teresa; De Vitis, Claudia; Zoppoli, Pietro; Ceccarelli, Michele; Riccardi, Miriam; Ravo, Maria; Weisz, Alessandro; Federico, Antonella; Franco, Renato; Rocco, Gaetano; Mancini, Rita; Rizzuto, Antonia; Gulletta, Elio; Ciliberto, Gennaro; Viglietto, Giuseppe

    2015-12-15

    Here we report that the PI3K/Akt1/IL-6/STAT3 signalling pathway regulates generation and stem cell-like properties of Non-Small Cell Lung Cancer (NSCLC) tumor initiating cells (TICs). Mutant Akt1, mutant PIK3CA or PTEN loss enhances formation of lung cancer spheroids (LCS), self-renewal, expression of stemness markers and tumorigenic potential of human immortalized bronchial cells (BEAS-2B) whereas Akt inhibition suppresses these activities in established (NCI-H460) and primary NSCLC cells. Matched microarray analysis of Akt1-interfered cells and LCSs identified IL-6 as a critical target of Akt signalling in NSCLC TICs. Accordingly, suppression of Akt in NSCLC cells decreases IL-6 levels, phosphorylation of IkK and IkB, NF-kB transcriptional activity, phosphorylation and transcriptional activity of STAT3 whereas active Akt1 up-regulates them. Exposure of LCSs isolated from NSCLC cells to blocking anti-IL-6 mAbs, shRNA to IL-6 receptor or to STAT3 markedly reduces the capability to generate LCSs, to self-renew and to form tumors, whereas administration of IL-6 to Akt-interfered cells restores the capability to generate LCSs. Finally, immunohistochemical studies in NSCLC patients demonstrated a positive correlative trend between activated Akt, IL-6 expression and STAT3 phosphorylation (n = 94; p cells in NSCLC.

  16. Clinicopathological Research and Expression of PTEN/PI3K/Akt Signaling Pathway in Non-small Cell Lung Cancer

    Directory of Open Access Journals (Sweden)

    Hong SHU

    2009-08-01

    Full Text Available Background and objective It has been known that abnormality of PTEN/PI3K/Akt signal pathway played an important role in initiation of some malignant tumors. The aim of this study is to examine the expression and clinicopathological significance of PTEN, PI3K and Akt in non-small cell lung cancer (NSCLC. Methods Expression levels of PTEN, PI3K and Akt protein were determined using immunohistochemistry S-P in 61 specimens of NSCLC with follow-up. Results ①The levels of PTEN protein was higher than that of control group, and levels of PI3K and Akt protein were lower than that of control group; ②Expression of PTEN and PI3K were related to histotype, clinical stage, lymphonode metastasis and survival rate; Expression of Akt was related to clinical stage, lymphonode metastasis and survival rate; ③The Cox Monovariable Analyses revealed that both smoking and negative expression of PTEN were the risking factors on the death of the NSCLC patients after surgery; ④The expression of PTEN protein was negatively correlated to that of PI3K and Akt respectively, while the expression of PI3K was positively correlated to that of Akt. Conclusion In NSCLC, the lack of PTEN induced up-regulation of PI3K and Akt, which demonstrated that PTEN/PI3K/Akt signaling pathway contributed to the tumorigenesis and development of NSCLC. They could be used as the indicators of prognosis and targets of therapy.

  17. ROLE OF PI3K-AKT-mTOR AND Wnt SIGNALING PATHWAYS IN G1-S TRANSITION OF CELL CYCLE IN CANCER CELLS

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    LAKSHMIPATHI eVADLAKONDA

    2013-04-01

    Full Text Available The PI3K–Akt pathway together with one of its downstream targets, the mechanistic target of rapamycin (mTOR is a highly deregulated pathway in cancers. There is a reciprocal relation between the Akt phosphorylation and mTOR complexes. Akt phosphorylated at T308 activates mTORC1 by inhibition of the tuberous sclerosis complex (TSC1/2, where as mTORC2 is recognized as the kinase that phosphorylates Akt at S473. Recent developments in the research on regulatory mechanisms of autophagy places mTORC1 mediated inhibition of autophagy at the central position in activation of proliferation and survival pathways in cells. Autophagy is a negative regulator of Wnt signaling pathway and the downstream effectors of Wnt signaling pathway, cyclin D1 and the c-Myc, are the key players in initiation of cell cycle and regulation of the G1-S transition in cancer cells. Production of reaction oxygen species (ROS, a common feature of a cancer cell metabolism, activates several downstream targets like the transcription factors FoxO, which play key roles in promoting the progression of cell cycle. A model is presented on the role of PI3K -Akt - mTOR and Wnt pathways in regulation of the progression of cell cycle through Go-G1-and S phases.

  18. Methylmercury, an environmental electrophile capable of activation and disruption of the Akt/CREB/Bcl-2 signal transduction pathway in SH-SY5Y cells

    Science.gov (United States)

    Unoki, Takamitsu; Abiko, Yumi; Toyama, Takashi; Uehara, Takashi; Tsuboi, Koji; Nishida, Motohiro; Kaji, Toshiyuki; Kumagai, Yoshito

    2016-01-01

    Methylmercury (MeHg) modifies cellular proteins via their thiol groups in a process referred to as “S-mercuration”, potentially resulting in modulation of the cellular signal transduction pathway. We examined whether low-dose MeHg could affect Akt signaling involved in cell survival. Exposure of human neuroblastoma SH-SY5Y cells of up to 2 μM MeHg phosphorylated Akt and its downstream signal molecule CREB, presumably due to inactivation of PTEN through S-mercuration. As a result, the anti-apoptotic protein Bcl-2 was up-regulated by MeHg. The activation of Akt/CREB/Bcl-2 signaling mediated by MeHg was, at least in part, linked to cellular defence because either pretreatment with wortmannin to block PI3K/Akt signaling or knockdown of Bcl-2 enhanced MeHg-mediated cytotoxicity. In contrast, increasing concentrations of MeHg disrupted Akt/CREB/Bcl-2 signaling. This phenomenon was attributed to S-mercuration of CREB through Cys286 rather than Akt. These results suggest that although MeHg is an apoptosis-inducing toxicant, this environmental electrophile is able to activate the cell survival signal transduction pathway at lower concentrations prior to apoptotic cell death. PMID:27357941

  19. Roles of the PI3K/Akt pathway in Epstein-Barr virus-induced cancers and therapeutic implications.

    Science.gov (United States)

    Chen, Jiezhong

    2012-12-12

    Viruses have been shown to be responsible for 10%-15% of cancer cases. Epstein-Barr virus (EBV) is the first virus to be associated with human malignancies. EBV can cause many cancers, including Burkett's lymphoma, Hodgkin's lymphoma, post-transplant lymphoproliferative disorders, nasopharyngeal carcinoma and gastric cancer. Evidence shows that phosphoinositide 3-kinase/protein kinase B (PI3K/Akt) plays a key role in EBV-induced malignancies. The main EBV oncoproteins latent membrane proteins (LMP) 1 and LMP2A can activate the PI3K/Akt pathway, which, in turn, affects cell survival, apoptosis, proliferation and genomic instability via its downstream target proteins to cause cancer. It has also been demonstrated that the activation of the PI3K/Akt pathway can result in drug resistance to chemotherapy. Thus, the inhibition of this pathway can increase the therapeutic efficacy of EBV-associated cancers. For example, PI3K inhibitor Ly294002 has been shown to increase the effect of 5-fluorouracil in an EBV-associated gastric cancer cell line. At present, dual inhibitors of PI3K and its downstream target mammalian target of rapamycin have been used in clinical trials and may be included in treatment regimens for EBV-associated cancers. PMID:24175221

  20. Role of PI3-K/Akt pathway and its effect on glial cell line-derived neurotrophic factor in midbrain dopamine cells

    Institute of Scientific and Technical Information of China (English)

    Hong-jun WANG; Jun-ping CAO; Jing-kao YU; Dian-shuai GAO

    2007-01-01

    Aim: To explore the intracellular mechanisms underlying the survival/differentia-don effect of the glial cell line-derived neurotrophic factor (GDNF) on dopamine(DA) cells. Methods: Midbrain slice culture and primary cell culture were established, and the cultures were divided into 3 groups: control group, GDNF group, and the phosphatidylinositol 3-kinase/Akt (PI3-K/Akt) pathway-inhibited group. Then the expression of tyrosine hydroxylase (TH) was detected by immunostaining as well as Western blotting. Results: GDNF treatment induced an increase in the number of TH-immunoreactive (ir) cells and the neurite number of TH-ir cells, as well as in the level of TH expression in cultures (Number of TH-ir cells in the slice culture: control group, 8.76±0.75; GDNF group, 18.63±0.95.Number of TH-ir cells and neurite number of TH-ir cells in cell culture: controlgroup, 3.65±0.88 and 2.49±0.42; GDNF group, 6.01±0.43 and 4.89±0.46). Meanwhile, the stimulation of cultured cells with GDNF increased the phosphorylation of Akt, which is a downstream effector of PI3-K/Akt. The effects of GDNF were specifically blocked by the inhibitor of the PI3-K/Akt pathway, wortmannin (Number of TH-ir cells in slice culture: PI3-K/Akt pathway-inhibited group, 6.98±0.58. Num-ber of TH-ir cells and neurite number of TH-ir cells in cell culture: PI3-K/Aktpathway-inhibited group, 3.79±0.62 and 2.50±0.25, respectively). Conclusion: The PI3-K/Akt pathway mediates the survival/differentiation effect of GDNF on DA cells.8±0.58.

  1. Phosphatidylinositol 3-kinase/Akt pathway regulates hepatic stellate cell apoptosis

    Institute of Scientific and Technical Information of China (English)

    Yan Wang; Xiao-Yu Jiang; Li Liu; Hui-Qing Jiang

    2008-01-01

    AIM:To investigate the role of phosphatidylinositol 3-kinase(PI 3-K)/Akt signaling pathway in the balance of HSC activation and apoptosis in rat hepatic stellate cells(HSC).METHODS:An activated HSC cell line was used in this study.LY 294002,the PI 3-K/Akt signal pathway blocker was used to investigate the molecular events on apoptosis in HSC and to interpret the role of this pathway in HSC apoptosis.Immunocytochemistry,Western blot and reverse transcription polymerase chain reaction(RT-PCR)analysis were applied to detect the expression of PI 3-K,and simultaneously phosphorylated-Akt(p-Akt)and total-Akt were determined by Western blot.The HSC apoptosis was examined by annexin-V/propidium iodide double-labelled flow cytometry and transmission electron microscopy.RESULTS:The apoptosis rates in LY 294002(30.82% ±2.90%)and LY 294002+PDGF-BB(28.16%±2.58%)groups were significantly increased compared with those of control(9.02%±1.81%)and PDGF-BB(4.35%±1.18%).PDGF-BB augmented PI 3-K and p-Akt expression.LY 294002 significantly reduced the contents of PI 3-K and p-Akt.mRNA transcription evaluated by RT-PCR showed similar tendencies as protein expression.CONCLUSION:Inhibition of PI 3-K/Akt signaling pathway Induces apoptosis in HSC.(C)2008 The WJG Press.All rights reserved.

  2. 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. PMID:26898450

  3. Oncogenic NanogP8 expression regulates cell proliferation and migration through the Akt/mTOR signaling pathway in human gastric cancer – SGC-7901cell line

    Directory of Open Access Journals (Sweden)

    Jiang Z

    2016-08-01

    Full Text Available Zheng Jiang, Yao Liu, Chuan Wang Department of Gastroenterology, The First Affiliated Hospital of Chongqing Medical University, Yuzhong District, Chongqing, People’s Republic of China Background: Although elevated expression of NanogP8 has been detected in many human tumor tissues, its role in gastric tumorigenesis remains unclear. Therefore, this study aimed to investigate the function and regulatory mechanism of NanogP8 in gastric cancer.Methods: In this study, NanogP8 cDNA was amplified by real time polymerase chain reaction from the human gastric cancer cell line SGC-7901. The shRNA for RNA interference was established. The NanogP8, pAkt, Akt, pERK, ERK, p-mTOR, and mTOR proteins were detected by using the Western blot assay. Cell viability was evaluated by using the CCK-8 assay. Cell migration and invasion were also examined by using the transwell assay.Results: The results indicated that the NanogP8 overexpression promoted proliferation and migration of SGC-7901 cell line, whereas its ablation exerted opposite effects. Interestingly, NanogP8 activated Akt, a key mediator of survival signals, and without affecting total Akt protein level. The NanogP8-increased gastric cell proliferation was downregulated by Akt inhibition. Our results further showed that increasing NanogP8 expression in human gastric cancer cells promoted cell proliferation by activating the AKT/mTOR pathway and further maintained gastric cell survival.Conclusion: Our findings extend the knowledge regarding the oncogenic functions and proved that the NanogP8 regulates cell proliferation and migration by Akt/mTOR signaling pathway in human gastric cancer SGC-7901cell line. Keywords: NanogP8, cell proliferation, Akt, mTOR

  4. The Role of AKT/mTOR Pathway in Stress Response to UV-Irradiation: Implication in Skin Carcinogenesis by Regulation of Apoptosis, Autophagy and Senescence

    Directory of Open Access Journals (Sweden)

    Elwira Strozyk

    2013-07-01

    Full Text Available Induction of DNA damage by UVB and UVA radiation may generate mutations and genomic instability leading to carcinogenesis. Therefore, skin cells being repeatedly exposed to ultraviolet (UV light have acquired multilayered protective mechanisms to avoid malignant transformation. Besides extensive DNA repair mechanisms, the damaged skin cells can be eliminated by induction of apoptosis, which is mediated through the action of tumor suppressor p53. In order to prevent the excessive loss of skin cells and to maintain the skin barrier function, apoptotic pathways are counteracted by anti-apoptotic signaling including the AKT/mTOR pathway. However, AKT/mTOR not only prevents cell death, but is also active in cell cycle transition and hyper-proliferation, thereby also counteracting p53. In turn, AKT/mTOR is tuned down by the negative regulators being controlled by the p53. This inhibition of AKT/mTOR, in combination with transactivation of damage-regulated autophagy modulators, guides the p53-mediated elimination of damaged cellular components by autophagic clearance. Alternatively, p53 irreversibly blocks cell cycle progression to prevent AKT/mTOR-driven proliferation, thereby inducing premature senescence. Conclusively, AKT/mTOR via an extensive cross talk with p53 influences the UV response in the skin with no black and white scenario deciding over death or survival.

  5. A novel Drosophila Girdin-like protein is involved in Akt pathway control of cell size

    Energy Technology Data Exchange (ETDEWEB)

    Puseenam, Aekkachai [Department of Applied Biology, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585 (Japan); Insect Biomedical Research Center, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585 (Japan); Yoshioka, Yasuhide [Department of Applied Biology, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585 (Japan); Venture Laboratory, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585 (Japan); Nagai, Rika [Department of Applied Biology, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585 (Japan); Insect Biomedical Research Center, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585 (Japan); Hashimoto, Reina [Department of Applied Biology, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585 (Japan); Venture Laboratory, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585 (Japan); Suyari, Osamu [Insect Biomedical Research Center, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585 (Japan); Itoh, Masanobu [Department of Applied Biology, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585 (Japan); Insect Biomedical Research Center, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585 (Japan); Enomoto, Atsushi [Department of Pathology, Center for Neurological Disease and Cancer, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Aichi 466-8550 (Japan); Takahashi, Masahide [Insect Biomedical Research Center, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585 (Japan); Department of Pathology, Center for Neurological Disease and Cancer, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Aichi 466-8550 (Japan); Yamaguchi, Masamitsu, E-mail: myamaguc@kit.ac.jp [Department of Applied Biology, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585 (Japan); Insect Biomedical Research Center, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585 (Japan)

    2009-11-15

    The Akt signaling pathway is well known to regulate cell proliferation and growth. Girdin, a novel substrate of Akt, plays a crucial role in organization of the actin cytoskeleton and cell motility under the control of Akt. We here identified a novel Girdin-like protein in Drosophila (dGirdin), which has two isoforms, dGirdin PA and dGirdin PB. dGirdin shows high homology with human Girdin in the N-terminal and coiled-coil domains, while diverging at the C-terminal domain. On establishment of transgenic fly lines, featuring knockdown or overexpression of dGirdin in vivo, overexpression in the wing disc cells induced ectopic apoptosis, implying a role in directing apoptosis. Knockdown of dGirdin in the Drosophila wing imaginal disc cells resulted in reduction of cell size. Furthermore, this was enhanced by half reduction of the Akt gene dose, suggesting that Akt positively regulates dGirdin. In the wing disc, cells in which dGirdin was knocked down exhibited disruption of actin filaments. From these in vivo analyses, we conclude that dGirdin is required for actin organization and regulation of appropriate cell size under control of the Akt signaling pathway.

  6. Dormancy of cancer cells with suppression of AKT activity contributes to survival in chronic hypoxia.

    Directory of Open Access Journals (Sweden)

    Hiroko Endo

    Full Text Available A hypoxic microenvironment in tumors has been recognized as a cause of malignancy or resistance to various cancer therapies. In contrast to recent progress in understanding the acute response of cancer cells to hypoxia, the characteristics of tumor cells in chronic hypoxia remain elusive. We have identified a pancreatic cancer cell line, AsPC-1, that is exceptionally able to survive for weeks under 1% oxygen conditions while most tested cancer cell lines die after only some days under these conditions. In chronic hypoxia, AsPC-1 cells entered a state of dormancy characterized by no proliferation, no death, and metabolic suppression. They reversibly switched to active status after being placed again in optimal culture conditions. ATP turnover, an indicator of energy demand, was markedly decreased and accompanied by reduced AKT phosphorylation. Forced activation of AKT resulted in increased ATP turnover and massive cell death in vitro and a decreased number of dormant cells in vivo. In contrast to most cancer cell lines, primary-cultured colorectal cancer cells easily entered the dormant status with AKT suppression under hypoxia combined with growth factor-depleted conditions. Primary colorectal cancer cells in dormancy were resistant to chemotherapy. Thus, the ability to survive in a deteriorated microenvironment by entering into dormancy under chronic hypoxia might be a common property among cancer cells. Targeting the regulatory mechanism inducing this dormant status could provide a new strategy for treating cancer.

  7. Oncogenic NanogP8 expression regulates cell proliferation and migration through the Akt/mTOR signaling pathway in human gastric cancer – SGC-7901cell line

    Science.gov (United States)

    Jiang, Zheng; Liu, Yao; Wang, Chuan

    2016-01-01

    Background Although elevated expression of NanogP8 has been detected in many human tumor tissues, its role in gastric tumorigenesis remains unclear. Therefore, this study aimed to investigate the function and regulatory mechanism of NanogP8 in gastric cancer. Methods In this study, NanogP8 cDNA was amplified by real time polymerase chain reaction from the human gastric cancer cell line SGC-7901. The shRNA for RNA interference was established. The NanogP8, pAkt, Akt, pERK, ERK, p-mTOR, and mTOR proteins were detected by using the Western blot assay. Cell viability was evaluated by using the CCK-8 assay. Cell migration and invasion were also examined by using the transwell assay. Results The results indicated that the NanogP8 overexpression promoted proliferation and migration of SGC-7901 cell line, whereas its ablation exerted opposite effects. Interestingly, NanogP8 activated Akt, a key mediator of survival signals, and without affecting total Akt protein level. The NanogP8-increased gastric cell proliferation was downregulated by Akt inhibition. Our results further showed that increasing NanogP8 expression in human gastric cancer cells promoted cell proliferation by activating the AKT/mTOR pathway and further maintained gastric cell survival. Conclusion Our findings extend the knowledge regarding the oncogenic functions and proved that the NanogP8 regulates cell proliferation and migration by Akt/mTOR signaling pathway in human gastric cancer SGC-7901cell line.

  8. [Signaling pathways mTOR and AKT in epilepsy].

    Science.gov (United States)

    Romero-Leguizamon, C R; Ramirez-Latorre, J A; Mora-Munoz, L; Guerrero-Naranjo, A

    2016-07-01

    Introduccion. La via de señalizacion AKT/mTOR es un eje central en la regulacion celular, especialmente en las enfermedades neurologicas. En la epilepsia, se ha evidenciado su alteracion dentro de su proceso fisiopatologico. Sin embargo, aun no se han descrito todos los mecanismos de estas rutas de señalizacion, las cuales podrian abrir la puerta hacia nuevas investigaciones y estrategias terapeuticas, que finalmente permitan desarrollar tratamientos efectivos en enfermedades neurologicas como la epilepsia. Objetivo. Revisar las asociaciones existentes entre las rutas de señalizacion intracelular de mTOR y AKT en la fisiopatologia de la epilepsia. Desarrollo. La epilepsia es una enfermedad neurologica con un alto impacto epidemiologico en el mundo, por lo cual es de sumo interes la investigacion de los componentes fisiopatologicos que puedan generar nuevos tratamientos farmacologicos. En esta busqueda se han involucrado diferentes rutas de señalizacion intracelular en neuronas, como determinantes epileptogenos. Los avances en esta materia han permitido incluso la implementacion de nuevas estrategias terapeuticas exitosas y que abren el camino hacia nuevas investigaciones. Conclusiones. Mejorar los conocimientos respecto al papel fisiopatologico de la via de señalizacion mTOR/AKT en la epilepsia permite plantear nuevas investigaciones que ofrezcan nuevas alternativas terapeuticas para el tratamiento de la enfermedad. El uso de inhibidores de mTOR ha surgido en los ultimos años como una alternativa eficaz en el tratamiento de algunos tipos de epilepsias, pero es evidente la necesidad de seguir en la busqueda de nuevas terapias farmacologicas involucradas en estas vias de señalizacion.

  9. Molecular characterization of the Akt-TOR signaling pathway in rainbow trout: potential role in muscle growth/degradation

    Science.gov (United States)

    The Akt-TOR signaling pathway plays a key role in cellular metabolism and muscle growth. Hormone, nutrition and stress factors affect the Akt-TOR pathway by regulating gene transcription, protein synthesis and degradation. In addition, we previously showed that energetic demands elevate during vit...

  10. PI3K/AKT pathway regulates E-cadherin and Desmoglein 2 in aggressive prostate cancer

    International Nuclear Information System (INIS)

    Reduced expression of both classical and desmosomal cadherins has been associated with different types of carcinomas, including prostate cancer. This study aims to provide a comprehensive view of the role and regulation of cell–cell adhesion in prostate cancer aggressiveness by examining the functional implications of both E-cadherin and Desmoglein 2 (DSG2). E-cadherin expression was first examined using immunofluorescence in 50 normal prostate tissues and in a cohort of 414 prostate cancer patients. Correlation and survival analyses were performed to assess its clinical significance. In primary prostate cancer patients, reduced expression of both E-cadherin and DSG2 is significantly associated with an earlier biochemical recurrence. Transgenic DU145 E-cadherin knockdown and constitutively active AKT overexpression lines were generated. Functional implications of such genetic alterations were analyzed in vitro and in vivo, the latter by using tumorigenesis as well as extravasation and metastatic tumor formation assays. We observed that loss of E-cadherin leads to impaired primary and metastatic tumor formation in vivo, suggesting a tumor promoter role for E-cadherin in addition to its known role as a tumor suppressor. Activation of AKT leads to a significant reduction in E-cadherin expression and nuclear localization of Snail, suggesting a role for the PI3K/AKT signaling pathway in the transient repression of E-cadherin. This reduced expression may be regulated by separate mechanisms as neither the loss of E-cadherin nor activation of AKT significantly affected DSG2 expression. In conclusion, these findings illustrate the critical role of cell–cell adhesion in the progression to aggressive prostate cancer, through regulation by the PI3K pathway

  11. Cell survival, cell death and cell cycle pathways are interconnected: Implications for cancer therapy

    DEFF Research Database (Denmark)

    Maddika, S; Ande, SR; Panigrahi, S;

    2007-01-01

    both for their apoptosis-regulating capacity and also for their effect on the cell cycle progression. The PI3-K/Akt cell survival pathway is shown as regulator of cell metabolism and cell survival, but examples are also provided where aberrant activity of the pathway may contribute to the induction...... of apoptosis. Myc/Mad/Max proteins are shown both as a powerful S-phase driving complex and as apoptosis-sensitizers. We also discuss multifunctional proteins like p53 and Rb (RBL1/p107, RBL2/p130) both in the context of G(1)-S transition and as apoptotic triggers. Finally, we reflect on novel therapeutic...

  12. 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

  13. Sensitization of Cervical Cancer Cells to Cisplatin by Genistein: The Role of NFB and Akt/mTOR Signaling Pathways

    Directory of Open Access Journals (Sweden)

    K. Sahin

    2012-01-01

    Full Text Available Cervical cancer is among the top causes of death from cancer in women. Cisplatin-based chemotherapy has been shown to improve survival; however, cisplatin treatment is associated with toxicity to healthy cells. Genistein has been used as an adjunct to chemotherapy to enhance the activity of chemotherapeutic agents without causing increased toxicity. The present study was designed to investigate the effect of genistein (25 μM on antitumor activity of cisplatin (250 nM on HeLa cervical cancer cells. We have examined the alterations in expression of NF-B, p-mTOR, p-p70S6K1, p-4E-BP1, and p-Akt protein levels in response to treatment. The combination of 25 μM genistein with 250 nM cisplatin resulted in significantly greater growth inhibition (. Genistein enhanced the antitumor activity of cisplatin and reduced the expression of NF-B, p-mTOR, p-p70S6K1, p-4E-BP1, and p-Akt. The results in the present study suggest that genistein could enhance the activity of cisplatin via inhibition of NF-κB and Akt/mTOR pathways. Genistein is a promising nontoxic nutritional agent that may enhance treatment outcome in cervical cancer patients when given concomitantly with cisplatin. Clinical trials of genistein and cisplatin combination are warranted to test this hypothesis.

  14. Dexamethasone (DEX induces Osmotic stress transcription factor 1 (Ostf1 through the Akt-GSK3β pathway in freshwater Japanese eel gill cell cultures

    Directory of Open Access Journals (Sweden)

    S. C. Chow

    2013-03-01

    Osmosensing and osmoregulatory processes undertaken in gills of euryhaline fish are coordinated by integrative actions of various signaling molecules/transcriptional factors. Considerable numbers of studies report the hyper- and hypo-osmoregulatory functions of fish gills, by illustrating the process of gill cell remodeling and the modulation of the expression of ion channels/transporters. Comparatively mechanistic information relayed from signal integration to transcriptional regulation in mediating gill cell functions has not yet been elucidated. In this study we demonstrate the functional links from cortisol stimulation, to Akt activation, to the expression of the transcriptional factor, Ostf1. Using the synthetic glucocorticoid receptor agonist, dexamethasone (DEX, Ostf1 expression is found to be activated via glucocorticoid receptor (GR and mediated by the Akt-GSK3β signaling pathway. Pharmacological experiments using kinase inhibitors reveal that the expression of Ostf1 is negatively regulated by Akt activation. The inhibition of PI3K or Akt activities, by the specific kinase inhibitors (wortmannin, LY294002 or SH6, stimulates Ostf1 expression, while a reduction of GSK3β activity by LiCl reduces Ostf1 expression. Collectively, our report for the first time indicates that DEX can induce Ostf1 via GR, with the involvement of the Akt-GSK3β signaling pathway in primary eel gill cell cultures. The data also suggest that Ostf1 may play different roles in gill cell survival during seawater acclimation.

  15. PDK1-Akt pathway regulates radial neuronal migration and microtubules in the developing mouse neocortex.

    Science.gov (United States)

    Itoh, Yasuhiro; Higuchi, Maiko; Oishi, Koji; Kishi, Yusuke; Okazaki, Tomohiko; Sakai, Hiroshi; Miyata, Takaki; Nakajima, Kazunori; Gotoh, Yukiko

    2016-05-24

    Neurons migrate a long radial distance by a process known as locomotion in the developing mammalian neocortex. During locomotion, immature neurons undergo saltatory movement along radial glia fibers. The molecular mechanisms that regulate the speed of locomotion are largely unknown. We now show that the serine/threonine kinase Akt and its activator phosphoinositide-dependent protein kinase 1 (PDK1) regulate the speed of locomotion of mouse neocortical neurons through the cortical plate. Inactivation of the PDK1-Akt pathway impaired the coordinated movement of the nucleus and centrosome, a microtubule-dependent process, during neuronal migration. Moreover, the PDK1-Akt pathway was found to control microtubules, likely by regulating the binding of accessory proteins including the dynactin subunit p150(glued) Consistent with this notion, we found that PDK1 regulates the expression of cytoplasmic dynein intermediate chain and light intermediate chain at a posttranscriptional level in the developing neocortex. Our results thus reveal an essential role for the PDK1-Akt pathway in the regulation of a key step of neuronal migration. PMID:27170189

  16. 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.

  17. 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. PMID:25002221

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

    Science.gov (United States)

    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.

  19. 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.

  20. Neurogenesis and Increase in Differentiated Neural Cell Survival via Phosphorylation of Akt1 after Fluoxetine Treatment of Stem Cells

    Directory of Open Access Journals (Sweden)

    Anahita Rahmani

    2013-01-01

    Full Text Available Fluoxetine (FLX is a selective serotonin reuptake inhibitor (SSRI. Its action is possibly through an increase in neural cell survival. The mechanism of improved survival rate of neurons by FLX may relate to the overexpression of some kinases such as Akt protein. Akt1 (a serine/threonine kinase plays a key role in the modulation of cell proliferation and survival. Our study evaluated the effects of FLX on mesenchymal stem cell (MSC fate and Akt1 phosphorylation levels in MSCs. Evaluation tests included reverse transcriptase polymerase chain reaction, western blot, and immunocytochemistry assays. Nestin, MAP-2, and β-tubulin were detected after neurogenesis as neural markers. Ten μM of FLX upregulated phosphorylation of Akt1 protein in induced hEnSC significantly. Also FLX did increase viability of these MSCs. Continuous FLX treatment after neurogenesis elevated the survival rate of differentiated neural cells probably by enhanced induction of Akt1 phosphorylation. This study addresses a novel role of FLX in neurogenesis and differentiated neural cell survival that may contribute to explaining the therapeutic action of fluoxetine in regenerative pharmacology.

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

    Science.gov (United States)

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

    2016-02-01

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

  2. Make Yourself at Home: Viral Hijacking of the PI3K/Akt Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Nora Diehl

    2013-12-01

    Full Text Available As viruses do not possess genes encoding for proteins required for translation, energy metabolism or membrane biosynthesis, they are classified as obligatory intracellular parasites that depend on a host cell to replicate. This genome limitation forces them to gain control over cellular processes to ensure their successful propagation. A diverse spectrum of virally encoded proteins tackling a broad spectrum of cellular pathways during most steps of the viral life cycle ranging from the host cell entry to viral protein translation has evolved. Since the host cell PI3K/Akt signaling pathway plays a critical regulatory role in many cellular processes including RNA processing, translation, autophagy and apoptosis, many viruses, in widely varying ways, target it. This review focuses on a number of remarkable examples of viral strategies, which exploit the PI3K/Akt signaling pathway for effective viral replication.

  3. Cellular stress-induced up-regulation of FMRP promotes cell survival by modulating PI3K-Akt phosphorylation cascades

    Directory of Open Access Journals (Sweden)

    Wells David

    2011-02-01

    Full Text Available Abstract Background Fragile X syndrome (FXS, the most commonly inherited mental retardation and single gene cause of autistic spectrum disorder, occurs when the Fmr1 gene is mutated. The product of Fmr1, fragile X linked mental retardation protein (FMRP is widely expressed in HeLa cells, however the roles of FMRP within HeLa cells were not elucidated, yet. Interacting with a diverse range of mRNAs related to cellular survival regulatory signals, understanding the functions of FMRP in cellular context would provide better insights into the role of this interesting protein in FXS. Using HeLa cells treated with etoposide as a model, we tried to determine whether FMRP could play a role in cell survival. Methods Apoptotic cell death was induced by etoposide treatment on Hela cells. After we transiently modulated FMRP expression (silencing or enhancing by using molecular biotechnological methods such as small hairpin RNA virus-induced knock down and overexpression using transfection with FMRP expression vectors, cellular viability was measured using propidium iodide staining, TUNEL staining, and FACS analysis along with the level of activation of PI3K-Akt pathway by Western blot. Expression level of FMRP and apoptotic regulator BcL-xL was analyzed by Western blot, RT-PCR and immunocytochemistry. Results An increased FMRP expression was measured in etoposide-treated HeLa cells, which was induced by PI3K-Akt activation. Without FMRP expression, cellular defence mechanism via PI3K-Akt-Bcl-xL was weakened and resulted in an augmented cell death by etoposide. In addition, FMRP over-expression lead to the activation of PI3K-Akt signalling pathway as well as increased FMRP and BcL-xL expression, which culminates with the increased cell survival in etoposide-treated HeLa cells. Conclusions Taken together, these results suggest that FMRP expression is an essential part of cellular survival mechanisms through the modulation of PI3K, Akt, and Bcl-xL signal

  4. 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.

  5. SIRT1 regulates MAPK pathways in vitiligo skin: insight into the molecular pathways of cell survival.

    Science.gov (United States)

    Becatti, Matteo; Fiorillo, Claudia; Barygina, Victoria; Cecchi, Cristina; Lotti, Torello; Prignano, Francesca; Silvestro, Agrippino; Nassi, Paolo; Taddei, Niccolò

    2014-03-01

    Vitiligo is an acquired and progressive hypomelanotic disease that manifests as circumscribed depigmented patches on the skin. The aetiology of vitiligo remains unclear, but recent experimental data underline the interactions between melanocytes and other typical skin cells, particularly keratinocytes. Our previous results indicate that keratinocytes from perilesional skin show the features of damaged cells. Sirtuins (silent mating type information regulation 2 homolog) 1, well-known modulators of lifespan in many species, have a role in gene repression, metabolic control, apoptosis and cell survival, DNA repair, development, inflammation, neuroprotection and healthy ageing. In the literature there is no evidence for SIRT1 signalling in vitiligo and its possible involvement in disease progression. Here, biopsies were taken from the perilesional skin of 16 patients suffering from non-segmental vitiligo and SIRT1 signalling was investigated in these cells. For the first time, a new SIRT1/Akt, also known as Protein Kinase B (PKB)/mitogen-activated protein kinase (MAPK) signalling has been revealed in vitiligo. SIRT1 regulates MAPK pathway via Akt-apoptosis signal-regulating kinase-1 and down-regulates pro-apoptotic molecules, leading to decreased oxidative stress and apoptotic cell death in perilesional vitiligo keratinocytes. We therefore propose SIRT1 activation as a novel way of protecting perilesional vitiligo keratinocytes from damage.

  6. Blocking the PI3K/AKT pathway enhances mammalian reovirus replication by repressing IFN-stimulated genes

    Science.gov (United States)

    Tian, Jin; Zhang, Xiaozhan; Wu, Hongxia; Liu, Chunguo; Li, Zhijie; Hu, Xiaoliang; Su, Shuo; Wang, Lin-Fa; Qu, Liandong

    2015-01-01

    Many host cellular signaling pathways were activated and exploited by virus infection for more efficient replication. The PI3K/Akt pathway has recently attracted considerable interest due to its role in regulating virus replication. This study demonstrated for the first time that the mammalian reovirus strains Masked Palm Civet/China/2004 (MPC/04) and Bat/China/2003 (B/03) can induce transient activation of the PI3K/Akt pathway early in infection in vitro. When UV-treated, both viruses activated PI3K/Akt signaling, indicating that the virus/receptor interaction was sufficient to activate PI3K/Akt. Reovirus virions can use both clathrin- and caveolae-mediated endocytosis, but only chlorpromazine, a specific inhibitor of clathrin-mediated endocytosis, or siRNA targeting clathrin suppressed Akt phosphorylation. We also identified the upstream molecules of the PI3K pathway. Virus infection induced phosphorylation of focal adhesion kinase (FAK) but not Gab1, and blockage of FAK phosphorylation suppressed Akt phosphorylation. Blockage of PI3K/Akt activation increased virus RNA synthesis and viral yield. We also found that reovirus infection activated the IFN-stimulated response element (ISRE) in an interferon-independent manner and up-regulated IFN-stimulated genes (ISGs) via the PI3K/Akt/EMSY pathway. Suppression of PI3K/Akt activation impaired the induction of ISRE and down-regulated the expression of ISGs. Overexpression of ISG15 and Viperin inhibited virus replication, and knockdown of either enhanced virus replication. Collectively, these results demonstrate that PI3K/Akt activated by mammalian reovirus serves as a pathway for sensing and then inhibiting virus replication/infection. PMID:26388843

  7. Activation of PI3K/Akt pathway limits JNK-mediated apoptosis during EV71 infection.

    Science.gov (United States)

    Zhang, Hua; Li, Fengqi; Pan, Ziye; Wu, Zhijun; Wang, Yanhong; Cui, Yudong

    2014-11-01

    Apoptosis is frequently induced to inhibit virus replication during infection of Enterovirus 71 (EV71). On the contrary, anti-apoptotic pathway, such as PI3K/Akt pathway, is simultaneously exploited by EV71 to accomplish the viral life cycle. The relationship by which EV71-induced apoptosis and PI3K/Akt signaling pathway remains to be elucidated. In this study, we demonstrated that EV71 infection altered Bax conformation and triggered its redistribution from the cytosol to mitochondria in RD cells. Subsequently, cytochrome c was released from mitochondria to cytosol. We also found that c-Jun NH2-terminal kinase (JNK) was activated during EV71 infection. The JNK specific inhibitor significantly inhibited Bax activation and cytochrome c release, suggesting that EV71-induced apoptosis was involved into a JNK-dependent manner. Meanwhile, EV71-induced Akt phosphorylation involved a PI3K-dependent mechanism. Inhibition of the PI3K/Akt pathway enhanced JNK phosphorylation and the JNK-mediated apoptosis upon EV71 infection. Moreover, PI3K/Akt pathway phosphorylated apoptosis signal-regulating kinase 1 (ASK1) and negatively regulated the ASK1 activity. Knockdown of ASK1 significantly decreased JNK phosphorylation, which implied that ASK1 phosphorylation by Akt inhibited ASK1-mediated JNK activation. Collectively, these data reveal that activation of the PI3K/Akt pathway limits JNK-mediated apoptosis by phosphorylating and inactivating ASK1 during EV71 infection.

  8. Increased cytotoxicity of ionizing radiation in combination with membrane-targeted apoptosis modulators involves downregulation of protein kinase B/Akt-mediated survival-signaling

    International Nuclear Information System (INIS)

    Background and purpose: The membrane-targeted apoptosis modulators erucylphosphocholine (ErPC) and erucylphosphohomocholine (ErPC3) induce apoptosis in highly apoptosis resistant malignant glioma cell lines and enhance radiation-induced cell death and eradication of clonogenic tumor cells in vitro. Aim of the present study was to elucidate molecular mechanisms of combined action. Materials and methods: Induction of apoptosis was evaluated by determination of nuclear morphology (fluorescence microscopy), alteration of mitochondrial function and caspase-activation (flow cytometry, Western blot). Activity of protein kinase B (PKB/Akt) and key downstream effectors involved in apoptosis regulation was verified by Western blot analysis using activation-specific antibodies. Results: Increased cytotoxicity of the combination was linked to a more efficient activation of the intrinsic apoptosis pathway with increased damage of the mitochondria and caspase-activation. Moreover, activity of the survival kinase PKB/Akt was downregulated upon treatment with ErPC/ErPC3 alone or in combination with ionizing radiation. Inhibition of PKB/Akt was associated with decreased phosphorylation and thus activation of the pro-apoptotic Bcl-2 protein Bad as well as dephosphorylation of the transcription factor FOXO3A (FKHRL1) that may be responsible for the observed increased expression of the pro-apoptotic Bcl-2 protein Bim. Conclusions: Our data suggest a role for inhibition of PKB/Akt-mediated anti-apoptotic signaling in increased efficacy of the combination

  9. Crosstalk between the IGF-1R/AKT/mTORC1 pathway and the tumor suppressors p53 and p27 determines cisplatin sensitivity and limits the effectiveness of an IGF-1R pathway inhibitor.

    Science.gov (United States)

    Davaadelger, Batzaya; Duan, Lei; Perez, Ricardo E; Gitelis, Steven; Maki, Carl G

    2016-05-10

    The insulin-like growth factor-1 receptor (IGF-1R) signaling pathway is aberrantly activated in multiple cancers and can promote proliferation and chemotherapy resistance. Multiple IGF-1R inhibitors have been developed as potential therapeutics. However, these inhibitors have failed to increase patient survival when given alone or in combination with chemotherapy agents. The reason(s) for the disappointing clinical effect of these inhibitors is not fully understood. Cisplatin (CP) activated the IGF-1R/AKT/mTORC1 pathway and stabilized p53 in osteosarcoma (OS) cells. p53 knockdown reduced IGF-1R/AKT/mTORC1 activation by CP, and IGF-1R inhibition reduced the accumulation of p53. These data demonstrate positive crosstalk between p53 and the IGF-1R/AKT/mTORC1 pathway in response to CP. Further studies showed the effect of IGF-1R inhibition on CP response is dependent on p53 status. In p53 wild-type cells treated with CP, IGF-1R inhibition increased p53s apoptotic function but reduced p53-dependent senescence, and had no effect on long term survival. In contrast, in p53-null/knockdown cells, IGF-1R inhibition reduced apoptosis in response to CP and increased long term survival. These effects were due to p27 since IGF-1R inhibition stabilized p27 in CP-treated cells, and p27 depletion restored apoptosis and reduced long term survival. Together, the results demonstrate 1) p53 expression determines the effect of IGF-1R inhibition on cancer cell CP response, and 2) crosstalk between the IGF-1R/AKT/mTORC1 pathway and p53 and p27 can reduce cancer cell responsiveness to chemotherapy and may ultimately limit the effectiveness of IGF-1R pathway inhibitors in the clinic. PMID:27050276

  10. Myocardial ischemic post-conditioning attenuates ischemia reperfusion injury via PTEN/Akt signal pathway

    OpenAIRE

    LI, CHUN-MEI; Shen, Shu-Wen; Tao WANG; Zhang, Xing-Hua

    2015-01-01

    Objectives: To investigate whether myocardial ischemic post-conditioning attenuates ischemia reperfusion injury via PTEN/Akt signal pathway. Design: Forty-five male Sprague-Dawley rats were randomly divided into three groups: Sham, Ischemia reperfusion (I/R) and Ischemic post-conditioning (IPost) group. After the experiment finished, myocardial infarction area was examined. Serum creatine phosphokinase and lactate dehydrogenase activity were detected at baseline and the end of reperfusion. Th...

  11. PPAR-γ ligands repress TGFβ-induced myofibroblast differentiation by targeting the PI3K/Akt pathway: implications for therapy of fibrosis.

    Directory of Open Access Journals (Sweden)

    Ajit A Kulkarni

    Full Text Available Transforming growth factor beta (TGFβ induced differentiation of human lung fibroblasts to myofibroblasts is a key event in the pathogenesis of pulmonary fibrosis. Although the typical TGFβ signaling pathway involves the Smad family of transcription factors, we have previously reported that peroxisome proliferator-activated receptor-γ (PPAR-γ ligands inhibit TGFβ-mediated differentiation of human lung fibroblasts to myofibroblasts via a Smad-independent pathway. TGFβ also activates the phosphatidylinositol 3 kinase/protein kinase B (PI3K/Akt pathway leading to phosphorylation of Akt(S473. Here, we report that PPAR-γ ligands, 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid (CDDO and 15-deoxy-(12,14-15d-prostaglandin J(2 (15d-PGJ(2, inhibit human myofibroblast differentiation of normal and idiopathic pulmonary fibrotic (IPF fibroblasts, by blocking Akt phosphorylation at Ser473 by a PPAR-γ-independent mechanism. The PI3K inhibitor LY294002 and a dominant-negative inactive kinase-domain mutant of Akt both inhibited TGFβ-stimulated myofibroblast differentiation, as determined by Western blotting for α-smooth muscle actin and calponin. Prostaglandin A(1 (PGA(1, a structural analogue of 15d-PGJ(2 with an electrophilic center, also reduced TGFβ-driven phosphorylation of Akt, while CAY10410, another analogue that lacks an electrophilic center, did not; implying that the activity of 15d-PGJ(2 and CDDO is dependent on their electrophilic properties. PPAR-γ ligands inhibited TGFβ-induced Akt phosphorylation via both post-translational and post-transcriptional mechanisms. This inhibition is independent of MAPK-p38 and PTEN but is dependent on TGFβ-induced phosphorylation of FAK, a kinase that acts upstream of Akt. Thus, PPAR-γ ligands inhibit TGFβ signaling by affecting two pro-survival pathways that culminate in myofibroblast differentiation. Further studies of PPAR-γ ligands and small electrophilic molecules may lead to a new generation of

  12. PFKL/miR-128 axis regulates glycolysis by inhibiting AKT phosphorylation and predicts poor survival in lung cancer.

    Science.gov (United States)

    Yang, Jie; Li, Jingqiu; Le, Yanping; Zhou, Chengwei; Zhang, Shun; Gong, Zhaohui

    2016-01-01

    MicroRNAs (miRNAs) affect cancer cell glucose metabolism by targeting mRNAs of diverse enzymes that have been implicated in oxidative phosphorylation (OXPHOS) and glycolytic pathways. However, the mechanisms that underlie miRNA-mediated regulation of phosphofructokinase (PFK), a key rate-limiting enzyme in glycolysis, remain largely unknown. Here, we show that miR-128 directly targets PFK liver type (PFKL) in lung cancer cells and regulates endogenous expression of PFKL at both the mRNA and protein levels. In line with this, overexpression of miR-128 decreased glucose uptake and lactate production, as well as increased cellular ATP content. Interestingly, knockdown of miR-128 was shown to promote lung cancer cell growth and colony formation. Moreover, we observed that miR-128 expression inversely correlated with PFKL mRNA levels in clinic lung cancer samples and that increased PFKL expression predicted poor overall survival in lung cancer patients. Mechanistically, we showed that miR-128 regulates PFKL via a feedback loop that involves inhibition of the AKT signaling pathway. Together, our results suggest that miR-128 acts as a metabolic regulator in lung cancer cells that may be therapeutically exploited. PMID:27186417

  13. Neurofilament heavy polypeptide regulates the Akt-beta-catenin pathway in human esophageal squamous cell carcinoma.

    Directory of Open Access Journals (Sweden)

    Myoung Sook Kim

    Full Text Available Aerobic glycolysis and mitochondrial dysfunction are common features of aggressive cancer growth. We observed promoter methylation and loss of expression in neurofilament heavy polypeptide (NEFH in a significant proportion of primary esophageal squamous cell carcinoma (ESCC samples that were of a high tumor grade and advanced stage. RNA interference-mediated knockdown of NEFH accelerated ESCC cell growth in culture and increased tumorigenicity in vivo, whereas forced expression of NEFH significantly inhibited cell growth and colony formation. Loss of NEFH caused up-regulation of pyruvate kinase-M2 type and down-regulation of pyruvate dehydrogenase, via activation of the Akt/beta-catenin pathway, resulting in enhanced aerobic glycolysis and mitochondrial dysfunction. The acceleration of glycolysis and mitochondrial dysfunction in NEFH-knockdown cells was suppressed in the absence of beta-catenin expression, and was decreased by the treatment of 2-Deoxyglucose, a glycolytic inhibitor, or API-2, an Akt inhibitor. Loss of NEFH activates the Akt/beta-catenin pathway and increases glycolysis and mitochondrial dysfunction. Cancer cells with methylated NEFH can be targeted for destruction with specific inhibitors of deregulated downstream pathways.

  14. Inhibition of STAT3 reverses alkylator resistance through modulation of the AKT and β-catenin signaling pathways.

    Science.gov (United States)

    Wang, Yongzhi; Chen, Lingchao; Bao, Zhaoshi; Li, Shouwei; You, Gan; Yan, Wei; Shi, Zhendong; Liu, Yanwei; Yang, Pei; Zhang, Wei; Han, Lei; Kang, Chunsheng; Jiang, Tao

    2011-11-01

    Activation of signal transducer and activator of transcription 3 (STAT3) is associated with poor clinical outcome of glioblastoma (GBM). However, the role of STAT3 in resistance to alkylator-based chemotherapy remains unknown. Here, we retrospectively analyzed the phosphorylated STAT3 (p-STAT3) profile of 68 GBM patients receiving alkylator therapy, identifying p-STAT3 as an independent unfavorable prognostic factor for progression-free and overall survival. Additionally, elevated p-STAT3 expression correlated with resistance to alkylator therapy. In vitro analysis revealed that U251 and U87 human glioma cells were refractory to treatment with the common alkylating agent temozolomide (TMZ), with only a modest impact on AKT and β-catenin activation in the context of high p-STAT3. Inhibition of STAT3 in these cells significantly enhanced the effect of TMZ. Inhibition of STAT3 dramatically decreased the IC50 of TMZ, increasing TMZ-induced apoptosis while up-regulating expression of Bcl-2 and down-regulating expression of Bax. Furthermore, inhibition of STAT3 increased TMZ-induced G₀-G₁ arrest and decreased Cyclin D1 expression compared to TMZ alone. Together, these results indicate that inhibition of STAT3 sensitizes glioma cells to TMZ, at least in part, by blocking the p-AKT and β-catenin pathways. These findings strongly support the hypothesis that STAT3 inhibition significantly improves the clinical efficacy of alkylating agents.

  15. Apolipoprotein CIII Reduces Proinflammatory Cytokine-Induced Apoptosis in Rat Pancreatic Islets via the Akt Prosurvival Pathway

    DEFF Research Database (Denmark)

    Størling, Joachim; Juntti-Berggren, Lisa; Olivecrona, Gunilla;

    2011-01-01

    Apolipoprotein CIII (ApoCIII) is mainly synthesized in the liver and is important for triglyceride metabolism. The plasma concentration of ApoCIII is elevated in patients with type 1 diabetes (T1D), and in vitro ApoCIII causes apoptosis in pancreatic ß-cells in the absence of inflammatory stress...... µg/ml) did not cause apoptosis. In the presence of the islet-cytotoxic cytokines IL-1ß + interferon-¿, ApoCIII reduced cytokine-mediated islet cell death and impairment of ß-cell function. ApoCIII had no effects on mitogen-activated protein kinases (c-Jun N-terminal kinase, p38, and ERK) and had...... of the survival serine-threonine kinase Akt. Inhibition of the Akt signaling pathway by the phosphatidylinositol 3 kinase inhibitor LY294002 counteracted the antiapoptotic effect of ApoCIII on cytokine-induced apoptosis. We conclude that ApoCIII in the presence of T1D-relevant proinflammatory cytokines reduces...

  16. Modulation of the Akt Pathway Reveals a Novel Link with PERK/eIF2α, which Is Relevant during Hypoxia

    OpenAIRE

    Blaustein, Matías; Pérez-Munizaga, Daniela; Sánchez, Manuel Alejandro; Urrutia, Carolina; Grande, Alicia; Risso, Guillermo; Srebrow, Anabella; Alfaro, Jennifer; Colman-Lerner, Alejandro

    2013-01-01

    The unfolded protein response (UPR) and the Akt signaling pathway share several regulatory functions and have the capacity to determine cell outcome under specific conditions. However, both pathways have largely been studied independently. Here, we asked whether the Akt pathway regulates the UPR. To this end, we used a series of chemical compounds that modulate PI3K/Akt pathway and monitored the activity of the three UPR branches: PERK, IRE1 and ATF6. The antiproliferative and antiviral drug ...

  17. Iron deficiency down-regulates the Akt/TSC1-TSC2/mammalian Target of Rapamycin signaling pathway in rats and in COS-1 cells.

    Science.gov (United States)

    Ndong, Moussa; Kazami, Machiko; Suzuki, Tsukasa; Uehara, Mariko; Katsumata, Shin-Ichi; Inoue, Hirohumi; Kobayashi, Ken-Ichi; Tadokoro, Tadahiro; Suzuki, Kazuharu; Yamamoto, Yuji

    2009-09-01

    Iron deficiency (ID) is one of the most commonly known forms of nutritional deficiencies. Low body iron is thought to induce neurologic defects but may also play a protective role against cancer development by cell growth arrest. Thus, ID may affect cellular pathways controlling cell growth and proliferation, the mechanism of which is still not fully understood. The serine/threonine protein kinase Akt and its downstream target, the mammalian Target of Rapamycin (mTOR), is known to play a crucial role in the regulation of cell growth and survival. Therefore, we hypothesized that Akt/mTOR pathway could be influenced by ID. Three-week-old male Wistar-strain rats were divided into 3 groups and the 2 groups had free access to a control diet (C group) or an iron-deficient diet (D group). The third group (PF group) were pair-fed the control diet to the mean intake of the D group. After 4 weeks, rats were killed and their brains were sampled. In separate experiments, COS-1 cells were cultured with or without the iron chelator deferoxamine. Western blots of brain samples and COS-1 lysates were used to analyze the expression and phosphorylation state of Akt, TSC2, mTOR, and S6 kinase proteins implicated in the Akt/mTOR pathway. Using 2 different ID models, we show for the first time that iron deficiency depresses Akt activity in rats and in COS-1 cells, leading to a decrease in mTOR activity. PMID:19854379

  18. The hepatitis B virus X protein promotes pancreatic cancer through modulation of the PI3K/AKT signaling pathway.

    Science.gov (United States)

    Chen, Yiwen; Bai, Xueli; Zhang, Qi; Wen, Liang; Su, Wei; Fu, Qihan; Sun, Xu; Lou, Yu; Yang, Jiaqi; Zhang, Jingying; Chen, Qi; Wang, Jianxin; Liang, Tingbo

    2016-09-28

    Pancreatic ductal adenocarcinoma (PDAC) is an aggressive and lethal cancer, with poor outcomes. Infection with the hepatitis B virus (HBV) may be associated as a worse prognosis for PDAC patients; however, the mechanisms involved in this process are unclear. We evaluated whether HBV infection leads to PDAC with a more aggressive phenotype, and attempted to elucidate the mechanisms involved. Clinicopathological data and outcomes from 64 patients with PDAC were collected and compared between serum HBsAg+ and HBsAg- patients. Furthermore, we examined the effects of the HBV X protein (HBx) on proliferation and migration of the pancreatic cancer cell lines PANC-1 and SW1990. We investigated expression changes of over 500 proteins by protein array analysis and identified several HBV- and PDAC-related candidates, which were further validated by immunoblotting and enzyme-linked immunosorbent assay. No differences in clinicopathological features were observed between HBsAg+ and HBsAg- patients; however, HBsAg+ patients had a shorter median survival time (8 vs. 13 months), although the differences were not significant. HBV DNA was detected in clinical specimens, even in PDAC patients considered "HBV-free", potentially due to occult infection. HBx expression significantly enhanced cellular proliferation and migration and induced an epithelial-mesenchymal transition phenotype. Expression of ErbB4 and TGF-α was increased in parallel with HBx expression, and several downstream pathways including PI3K/AKT, MAPK, and ERK were upregulated. Inhibition of the PI3K/AKT pathway reversed the effects of HBx in PDAC cell lines. HBx may, therefore, contribute to the progression of PDAC through modulation of these pathways. PMID:27339327

  19. L-3-n-butylphthalide protects against vascular dementia via activation of the Akt kinase pathway**

    Institute of Scientific and Technical Information of China (English)

    Yaping Huai; Yanhong Dong; Jing Xu; Nan Meng; Chunfeng Song; Wenbin Li; Peiyuan Lv

    2013-01-01

    As a neuroprotective drug for the treatment of ischemic stroke, 3-n-butylphthalide, a celery seed ex-tract, has been approved by the State Food and Drug Administration of China as a clinical therapeutic drug for ischemic stroke patients. L-3-n-butylphthalide possesses significant efficacy in the treatment of acute ischemic stroke. The activated Akt kinase pathway can prevent the death of nerve cel s and exhibit neuroprotective effects in the brain after stroke. This study provides the hypothesis that l-3-n-butylphthalide has a certain therapeutic effect on vascular dementia, and its mechanism depends on the activation of the Akt kinase pathway. A vascular dementia mouse model was established by cere-bral repetitive ischemia/reperfusion, and intragastrical y administered l-3-n-butylphthalide daily for 28 consecutive days after ischemia/reperfusion, or 7 consecutive days before ischemia/reperfusion. The Morris water maze test showed significant impairment of spatial learning and memory at 4 weeks after operation, but intragastric administration of l-3-n-butylphthalide, especial y pretreatment with l-3-n-butylphthalide, significantly reversed these changes. Thionine staining and western blot analylsis showed that preventive and therapeutic application of l-3-n-butylphthalide can reduce loss of pyrami-dal neurons in the hippocampal CA1 region and al eviate nerve damage in mice with vascular demen-tia. In addition, phosphorylated Akt expression in hippocampal tissue increased significantly after l-3-n-butylphthalide treatment. Experimental findings demonstrate that l-3-n-butylphthalide has preventive and therapeutic effects on vascular dementia, and its mechanism may be mediated by upregulation of phosphorylated Akt in the hippocampus.

  20. Antiapoptotic effects of erythropoietin in differentiated neuroblastoma SH-SY5Y cells require activation of both the STAT5 and AKT signaling pathways.

    Science.gov (United States)

    Um, Moonkyoung; Lodish, Harvey F

    2006-03-01

    The hematopoietic cytokine erythropoietin (Epo) prevents neuronal death during ischemic events in the brain and in neurodegenerative diseases, presumably through its antiapoptotic effects. To explore the role of different signaling pathways in Epo-mediated antiapoptotic effects in differentiated human neuroblastoma SH-SY5Y cells, we employed a prolactin receptor (PrlR)/erythropoietin receptor (EpoR) chimera system, in which binding of prolactin (Prl) to the extracellular domain activates EpoR signaling in the cytosol. On induction of apoptosis by staurosporine, Prl supports survival of the SH-SY5Y cells expressing the wild-type PrlR/EpoR chimera. In these cells Prl treatment strongly activates the STAT5, AKT, and MAPK signaling pathways and induces weak activation of the p65 NF-kappaB factor. Selective mutation of the eight tyrosine residues of the EpoR cytoplasmic domain results in impaired or absent activation of either STAT5 (mutation of Tyr(343)) or AKT (mutation of Tyr(479)) or both (mutation of all eight tyrosine residues). Most interestingly, Prl treatment does not prevent apoptosis in cells expressing mutant PrlR/EpoR chimeras in which either the STAT5 or the AKT signaling pathways are not activated. In contrast, ERK 1/2 is fully activated by all mutant PrlR/EpoR chimeras, comparable with the level seen with the wild-type PrlR/EpoR chimera, implying that activation of the MAPK signaling pathway per se is not sufficient for antiapoptotic activity. Therefore, the antiapoptotic effects of Epo in neuronal cells require the combinatorial activation of multiple signaling pathways, including STAT5, AKT, and potentially MAPK as well, in a manner similar to that observed in hematopoietic cells.

  1. Lutein Inhibits the Migration of Retinal Pigment Epithelial Cells via Cytosolic and Mitochondrial Akt Pathways (Lutein Inhibits RPE Cells Migration

    Directory of Open Access Journals (Sweden)

    Ching-Chieh Su

    2014-08-01

    Full Text Available During the course of proliferative vitreoretinopathy (PVR, the retinal pigment epithelium (RPE cells will de-differentiate, proliferate, and migrate onto the surfaces of the sensory retina. Several studies have shown that platelet-derived growth factor (PDGF can induce migration of RPE cells via an Akt-related pathway. In this study, the effect of lutein on PDGF-BB-induced RPE cells migration was examined using transwell migration assays and Western blot analyses. We found that both phosphorylation of Akt and mitochondrial translocation of Akt in RPE cells induced by PDGF-BB stimulation were suppressed by lutein. Furthermore, the increased migration observed in RPE cells with overexpressed mitochondrial Akt could also be suppressed by lutein. Our results demonstrate that lutein can inhibit PDGF-BB induced RPE cells migration through the inhibition of both cytoplasmic and mitochondrial Akt activation.

  2. Modulation of the Akt Pathway Reveals a Novel Link with PERK/eIF2α, which Is Relevant during Hypoxia

    Science.gov (United States)

    Sánchez, Manuel Alejandro; Urrutia, Carolina; Grande, Alicia; Risso, Guillermo; Srebrow, Anabella; Alfaro, Jennifer; Colman-Lerner, Alejandro

    2013-01-01

    The unfolded protein response (UPR) and the Akt signaling pathway share several regulatory functions and have the capacity to determine cell outcome under specific conditions. However, both pathways have largely been studied independently. Here, we asked whether the Akt pathway regulates the UPR. To this end, we used a series of chemical compounds that modulate PI3K/Akt pathway and monitored the activity of the three UPR branches: PERK, IRE1 and ATF6. The antiproliferative and antiviral drug Akt-IV strongly and persistently activated all three branches of the UPR. We present evidence that activation of PERK/eIF2α requires Akt and that PERK is a direct Akt target. Chemical activation of this novel Akt/PERK pathway by Akt-IV leads to cell death, which was largely dependent on the presence of PERK and IRE1. Finally, we show that hypoxia-induced activation of eIF2α requires Akt, providing a physiologically relevant condition for the interaction between Akt and the PERK branch of the UPR. These data suggest the UPR and the Akt pathway signal to one another as a means of controlling cell fate. PMID:23922774

  3. Modulation of the Akt pathway reveals a novel link with PERK/eIF2α, which is relevant during hypoxia.

    Directory of Open Access Journals (Sweden)

    Matías Blaustein

    Full Text Available The unfolded protein response (UPR and the Akt signaling pathway share several regulatory functions and have the capacity to determine cell outcome under specific conditions. However, both pathways have largely been studied independently. Here, we asked whether the Akt pathway regulates the UPR. To this end, we used a series of chemical compounds that modulate PI3K/Akt pathway and monitored the activity of the three UPR branches: PERK, IRE1 and ATF6. The antiproliferative and antiviral drug Akt-IV strongly and persistently activated all three branches of the UPR. We present evidence that activation of PERK/eIF2α requires Akt and that PERK is a direct Akt target. Chemical activation of this novel Akt/PERK pathway by Akt-IV leads to cell death, which was largely dependent on the presence of PERK and IRE1. Finally, we show that hypoxia-induced activation of eIF2α requires Akt, providing a physiologically relevant condition for the interaction between Akt and the PERK branch of the UPR. These data suggest the UPR and the Akt pathway signal to one another as a means of controlling cell fate.

  4. Metformin and rapamycin have distinct effects on the AKT pathway and proliferation in breast cancer cells.

    Science.gov (United States)

    Zakikhani, Mahvash; Blouin, Marie-José; Piura, Esther; Pollak, Michael N

    2010-08-01

    Rapamycin and its analogues inhibit mTOR, which leads to decreased protein synthesis and decreased cancer cell proliferation in many experimental systems. Adenosine 5'- monophosphate-activated protein kinase (AMPK) activators such as metformin have similar actions, in keeping with the TSC2/1 pathway linking activation of AMPK to inhibition of mTOR. As mTOR inhibition by rapamycin is associated with attenuation of negative feedback to IRS-1, rapamycin is known to increase activation of AKT, which may reduce its anti-neoplastic activity. We observed that metformin exposure decreases AKT activation, an action opposite to that of rapamycin. We show that metformin (but not rapamycin) exposure leads to increased phosphorylation of IRS-1 at Ser(789), a site previously reported to inhibit downstream signaling and to be an AMPK substrate phosphorylated under conditions of cellular energy depletion. siRNA methods confirmed that reduction of AMPK levels attenuates both the IRS-1 Ser(789) phosphorylation and the inhibition of AKT activation associated with metformin exposure. Although both rapamycin and metformin inhibit mTOR (the former directly and the latter through AMPK signaling), our results demonstrate previously unrecognized differences between these agents. The data are consistent with the observation that maximal induction of apoptosis and inhibition of proliferation are greater for metformin than rapamycin. PMID:20135346

  5. Nafamostat mesilate promotes endothelium-dependent vasorelaxation via the Akt-eNOS dependent pathway

    Science.gov (United States)

    Choi, Sujeong; Kwon, Hyon-Jo; Song, Hee-Jung; Choi, Si Wan; Nagar, Harsha; Piao, Shuyu; Jung, Saet-byel; Jeon, Byeong Hwa

    2016-01-01

    Nafamostat mesilate (NM), a synthetic serine protease inhibitor, has anticoagulant and anti-inflammatory properties. The intracellular mediator and external anti-inflammatory external signal in the vascular wall have been reported to protect endothelial cells, in part due to nitric oxide (NO) production. This study was designed to examine whether NM exhibit endothelium dependent vascular relaxation through Akt/endothelial nitric oxide synthase (eNOS) activation and generation of NO. NM enhanced Akt/eNOS phosphorylation and NO production in a dose- and time-dependent manner in human umbilical vein endothelial cells (HUVECs) and aorta tissues obtained from rats treated with various concentrations of NM. NM concomitantly decreased arginase activity, which could increase the available arginine substrate for NO production. Moreover, we investigated whether NM increased NO bioavailability and decreased aortic relaxation response to an eNOS inhibitor in the aorta. These results suggest that NM increases NO generation via the Akt/eNOS signaling pathway, leading to endothelium-dependent vascular relaxation. Therefore, the vasorelaxing action of NM may contribute to the regulation of cardiovascular function. PMID:27610041

  6. Depression of p53-independent Akt survival signals after high-LET radiation in mutated p53 cells

    Science.gov (United States)

    Ohnishi, Takeo; Takahashi, Akihisa; Nakagawa, Yosuke

    Although mutations and deletions in the p53 tumor suppressor gene lead to resistance to low linear energy transfer (LET) radiation, high-LET radiation efficiently induces cell lethality and apoptosis regardless of the p53 gene status. Recently, it has been suggested that the induction of p53-independent apoptosis takes place through the activation of Caspase-9 which results in the cleavage of Caspase-3 and poly (ADP-ribose) polymerase (PARP). This study was designed to examine if high-LET radiation depresses the activities of serine/threonine protein kinase B (PKB, also known as Akt) and Akt-related proteins. Human gingival cancer cells (Ca9-22 cells) harboring a mutated p53 (mp53) gene were irradiated with 2 Gy of X-rays or Fe-ion beams. The cellular contents of Akt-related proteins participating in cell survival signals were analyzed with Western blotting analysis 1 h, 2 h, 3 h and 6 h after irradiation. Cell cycle distributions after irradiation were assayed with flow cytometric analysis.Akt-related protein levels were decreased when cells were irradiated with high-LET radiation. High-LET radiation increased G _{2}/M phase arrests and suppressed the progression of the cell cycle much more efficiently when compared to low-LET radiation. These results suggest that high-LET radiation enhances apoptosis through the activation of Caspase-3 and Caspase-9, and depresses cell growth by suppressing Akt-related signals, even in the mp53 cells.

  7. Down-regulation of Akt/mammalian target of rapamycin signaling pathway in response to myostatin overexpression in skeletal muscle.

    OpenAIRE

    Amirouche, Adel; Durieux, Anne-Cécile; Banzet, Sébastien; Koulmann, Nathalie; Bonnefoy, Régis; Mouret, Catherine; Bigard, Xavier; Peinnequin, André; Freyssenet, Damien

    2009-01-01

    Myostatin, a member of the TGF-beta family, has been identified as a master regulator of embryonic myogenesis and early postnatal skeletal muscle growth. However, cumulative evidence also suggests that alterations in skeletal muscle mass are associated with dysregulation in myostatin expression and that myostatin may contribute to muscle mass loss in adulthood. Two major branches of the Akt pathway are relevant for the regulation of skeletal muscle mass, the Akt/mammalian target of rapamycin ...

  8. Coprinus comatus cap inhibits adipocyte differentiation via regulation of PPARγ and Akt signaling pathway.

    Directory of Open Access Journals (Sweden)

    Hyoung Joon Park

    Full Text Available This study assessed the effects of Coprinus comatus cap (CCC on adipogenesis in 3T3-L1 adipocytes and the effects of CCC on the development of diet-induced obesity in rats. Here, we showed that the CCC has an inhibitory effect on the adipocyte differentiation of 3T3-L1 cells, resulting in a significant decrease in lipid accumulation through the downregulation of several adipocyte specific-transcription factors, including CCAAT/enhancer binding protein β, C/EBPδ, and peroxisome proliferator-activated receptor gamma (PPARγ. Moreover, treatment with CCC during adipocyte differentiation induced a significant down-regulation of PPARγ and adipogenic target genes, including adipocyte protein 2, lipoprotein lipase, and adiponectin. Interestingly, the CCC treatment of the 3T3-L1 adipocytes suppressed the insulin-stimulated Akt and GSK3β phosphorylation, and these effects were stronger in the presence of an inhibitor of Akt phosphorylation, LY294002, suggesting that CCC inhibited adipocyte differentiation through the down-regulation of Akt signaling. In the animal study, CCC administration significantly reduced the body weight and adipose tissue weight of rats fed a high fat diet (HFD and attenuated lipid accumulation in the adipose tissues of the HFD-induced obese rats. The size of the adipocyte in the epididymal fat of the CCC fed rats was significantly smaller than in the HFD rats. CCC treatment significantly reduced the total cholesterol and triglyceride levels in the serum of HFD rats. These results strongly indicated that the CCC-mediated decrease in body weight was due to a reduction in adipose tissue mass. The expression level of PPARγ and phospho-Akt was significantly lower in the CCC-treated HFD rats than that in the HFD obesity rats. These results suggested that CCC inhibited adipocyte differentiation by the down-regulation of major transcription factor involved in the adipogenesis pathway including PPARγ through the regulation of the

  9. Leucine minimizes denervation-induced skeletal muscle atrophy of rats through akt/mtor signaling pathways

    Directory of Open Access Journals (Sweden)

    Carolina Barbosa Ribeiro

    2015-03-01

    Full Text Available The aim of the present study was to evaluate the effect of leucine treatment (0.30 mM on muscle weight and signaling of myoproteins related to synthesis and degradation pathways of soleus muscle following seven days of complete sciatic nerve lesion.Wistar rats (n=24 of 3 to 4 months of age (192 ± 23 g were used. The animals were randomly distributed into four experimental groups (n=6/group: control, treated with leucine (L, denervated (D and denervated treated with leucine (DL.Dependent measures were proteins levels of AKT, AMPK, mTOR, and ACC performed by Western blot. Leucine induced a reduction in the phosphorylation of AMPK (p<0.05 by 16% in the L and by 68% in the DL groups as compared with control group. Denervation increased AMPK by 24% in the D group as compared with the control group (p<0.05. AKT was also modulated by denervation and leucine treatment, highlighted by the elevation of AKT phosphorylation in the D (65%, L (98% and DL (146% groups as compared with the control group (p<0.05. AKT phosphorylation was 49% higher in the D group as compared with the DL group.Furthermore, denervation decreased mTOR phosphorylation by 29% in the D group as compared with the control group. However, leucine treatment induced an increase of 49% in the phosphorylation of mTOR in the L group as compared with the control group, and an increase of 154% in the DL as compared with the D group ( p<0.05. ACC phosphorylation was 20% greater in the D group than the control group. Furthermore, ACC in the soleus was 22% lower in the in the L group and 50% lower in the DL group than the respective control group (p<0.05.In conclusion, leucine treatment minimized the deleterious effects of denervation on rat soleus muscle by increasing anabolic (AKT and mTOR and decreasing catabolic (AMPK pathways. These results may be interesting for muscle recovery following acute denervation, which may contribute to musculoskeletal rehabilitation after denervation.

  10. BRAF inhibitor resistance mediated by the AKT pathway in an oncogenic BRAF mouse melanoma model.

    Science.gov (United States)

    Perna, Daniele; Karreth, Florian A; Rust, Alistair G; Perez-Mancera, Pedro A; Rashid, Mamunur; Iorio, Francesco; Alifrangis, Constantine; Arends, Mark J; Bosenberg, Marcus W; Bollag, Gideon; Tuveson, David A; Adams, David J

    2015-02-10

    BRAF (v-raf murine sarcoma viral oncogene homolog B) inhibitors elicit a transient anti-tumor response in ∼ 80% of BRAF(V600)-mutant melanoma patients that almost uniformly precedes the emergence of resistance. Here we used a mouse model of melanoma in which melanocyte-specific expression of Braf(V618E) (analogous to the human BRAF(V600E) mutation) led to the development of skin hyperpigmentation and nevi, as well as melanoma formation with incomplete penetrance. Sleeping Beauty insertional mutagenesis in this model led to accelerated and fully penetrant melanomagenesis and synchronous tumor formation. Treatment of Braf(V618E) transposon mice with the BRAF inhibitor PLX4720 resulted in tumor regression followed by relapse. Analysis of transposon insertions identified eight genes including Braf, Mitf, and ERas (ES-cell expressed Ras) as candidate resistance genes. Expression of ERAS in human melanoma cell lines conferred resistance to PLX4720 and induced hyperphosphorylation of AKT (v-akt murine thymoma viral oncogene homolog 1), a phenotype reverted by combinatorial treatment with PLX4720 and the AKT inhibitor MK2206. We show that ERAS expression elicits a prosurvival signal associated with phosphorylation/inactivation of BAD, and that the resistance of hepatocyte growth factor-treated human melanoma cells to PLX4720 can be reverted by treatment with the BAD-like BH3 mimetic ABT-737. Thus, we define a role for the AKT/BAD pathway in resistance to BRAF inhibition and illustrate an in vivo approach for finding drug resistance genes.

  11. Interleukin-6 upregulates paraoxonase 1 gene expression via an AKT/NF-κB-dependent pathway

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Chi-Chih [Department of Research, Taichung Veterans General Hospital, Taichung, Taiwan (China); Hsueh, Chi-Mei [Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan (China); Chen, Chiu-Yuan [Graduate Institute of Natural Healing Sciences, Nanhua University, Chiayi, Taiwan (China); Chen, Tzu-Hsiu, E-mail: hsiu@mail.chna.edu.tw [Department of Health and Nutrition, Chia Nan University of Pharmacy and Science, Tainan, Taiwan (China); Hsu, Shih-Lan, E-mail: h2326@vghtc.gov.tw [Department of Research, Taichung Veterans General Hospital, Taichung, Taiwan (China); Department of Applied Chemistry, National Chi Nan University, Puli, Nantou, Taiwan (China)

    2013-07-19

    Highlights: •IL-6 could induce PON1 gene expression. •IL-6 increased NF-κB protein expression and NF-κB-p50 and -p65 subunits nuclear translocation. •IL-6-induced PON1 up-regulation was through an AKT/NF-κB pathway. -- Abstract: The aim of this study is to investigate the relationship between paraoxonase 1 (PON1) and atherosclerosis-related inflammation. In this study, human hepatoma HepG2 cell line was used as a hepatocyte model to examine the effects of the pro-inflammatory cytokines on PON1 expression. The results showed that IL-6, but not TNF-α and IL-1β, significantly increased both the function and protein level of PON1; data from real-time RT-PCR analysis revealed that the IL-6-induced PON1 expression occurred at the transcriptional level. Increase of IκB kinase activity and IκB phosphorylation, and reduction of IκB protein level were also observed in IL-6-treated HepG2 cells compared with untreated culture. This event was accompanied by increase of NF-κB-p50 and -p65 nuclear translocation. Moreover, treatment with IL-6 augmented the DNA binding activity of NF-κB. Furthermore, pharmacological inhibition of NF-κB activation by PDTC and BAY 11-7082, markedly suppressed the IL-6-mediated PON1 expression. In addition, IL-6 increased the levels of phosphorylated protein kinase B (PKB, AKT). An AKT inhibitor LY294002 effectively suppressed IKK/IκB/NF-κB signaling and PON1 gene expression induced by IL-6. Our findings demonstrate that IL-6 upregulates PON1 gene expression through an AKT/NF-κB signaling axis in human hepatocyte-derived HepG2 cell line.

  12. S6K Promotes Dopaminergic Neuronal Differentiation Through PI3K/Akt/mTOR-Dependent Signaling Pathways in Human Neural Stem Cells.

    Science.gov (United States)

    Lee, Jeong Eun; Lim, Mi Sun; Park, Jae Hyun; Park, Chang Hwan; Koh, Hyun Chul

    2016-08-01

    It has recently been reported that the phosphoinositide 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling pathway regulates neuronal differentiation of neural stem cells (NSCs) derived from rats or mice and is essential for the self-renewal of human embryonic stem cells (hESCs). However, the roles of PI3K/Akt/mTOR signaling pathways during proliferation and dopaminergic neuronal differentiation of human neural stem cells (hNSCs) are poorly understood. In this study, we examined the effect of regulation of these intracellular signaling pathways in hNSCs on the potential to maintain proliferation and induce dopaminergic neuronal differentiation. Dopaminergic neuronal differentiation depended on the concentration of insulin in our culture system. Inhibition of PI3K/Akt with LY294002 reduced proliferation and inhibited dopaminergic neuronal differentiation of these cells. We also found that rapamycin, a specific inhibitor of mTOR, significantly reduced neuronal differentiation without affecting proliferation. Inhibition of the Akt/mTOR signaling pathway led to inhibition of p70 ribosomal S6 kinase (S6K) signaling, which reduced dopaminergic neuronal differentiation in hNSCs. Inhibition of S6K by a specific chemical inhibitor, PF-4708671 inhibited dopaminergic neuronal differentiation of hNSCs. As expected, transduction with a dominant negative S6K1 (S6K1-DN) construct impaired dopaminergic neuronal differentiation of hNSCs. Conversely, overexpression of constitutively active S6K1 (S6K1-CA) promoted dopaminergic neuronal differentiation of these cells. In a survival study, 4 weeks after transplantation, no or very few donor cells were viable in striata grafted with S6K1-DN-transduced hNSCs. In contrast, S6K1-CA-transduced hNSCs survived, integrated into striata to generate tubular masses of grafts and differentiated toward TH-positive cells. Taken together, these data demonstrated that insulin promotes dopaminergic neuronal differentiation through a PI

  13. Mechanical stretch increases MMP-2 production in vascular smooth muscle cells via activation of PDGFR-β/Akt signaling pathway.

    Directory of Open Access Journals (Sweden)

    Kyo Won Seo

    Full Text Available Increased blood pressure, leading to mechanical stress on vascular smooth muscle cells (VSMC, is a known risk factor for vascular remodeling via increased activity of matrix metalloproteinase (MMP within the vascular wall. This study aimed to identify cell surface mechanoreceptors and intracellular signaling pathways that influence VSMC to produce MMP in response to mechanical stretch (MS. When VSMC was stimulated with MS (0-10% strain, 60 cycles/min, both production and gelatinolytic activity of MMP-2, but not MMP-9, were increased in a force-dependent manner. MS-enhanced MMP-2 expression and activity were inhibited by molecular inhibition of Akt using Akt siRNA as well as by PI3K/Akt inhibitors, LY293002 and AI, but not by MAPK inhibitors such as PD98059, SP600125 and SB203580. MS also increased Akt phosphorylation in VSMC, which was attenuated by AG1295, a PDGF receptor (PDGFR inhibitor, but not by inhibitors for other receptor tyrosine kinase including EGF, IGF, and FGF receptors. Although MS activated PDGFR-α as well as PDGFR-β in VSMC, MS-induced Akt phosphorylation was inhibited by molecular deletion of PDGFR-β using siRNA, but not by inhibition of PDGFR-α. Collectively, our data indicate that MS induces MMP-2 production in VSMC via activation of Akt pathway, that is mediated by activation of PDGFR-β signaling pathways.

  14. Vasopressin activates Akt/mTOR pathway in smooth muscle cells cultured in high glucose concentration

    Energy Technology Data Exchange (ETDEWEB)

    Montes, Daniela K.; Brenet, Marianne; Muñoz, Vanessa C.; Burgos, Patricia V.; Villanueva, Carolina I. [Department of Physiology, Universidad Austral de Chile, Valdivia 509-9200 (Chile); Figueroa, Carlos D. [Department of Anatomy, Histology and Pathology, Universidad Austral de Chile, Valdivia 509-9200 (Chile); González, Carlos B., E-mail: cbgonzal@uach.cl [Department of Physiology, Universidad Austral de Chile, Valdivia 509-9200 (Chile); Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX 77555 (United States)

    2013-11-29

    Highlights: •AVP induces mTOR phosphorylation in A-10 cells cultured in high glucose concentration. •The mTOR phosphorylation is mediated by the PI3K/Akt pathway activation. •The AVP-induced mTOR phosphorylation inhibited autophagy and stimulated cell proliferation. -- Abstract: Mammalian target of rapamycin (mTOR) complex is a key regulator of autophagy, cell growth and proliferation. Here, we studied the effects of arginine vasopressin (AVP) on mTOR activation in vascular smooth muscle cells cultured in high glucose concentration. AVP induced the mTOR phosphorylation in A-10 cells grown in high glucose, in contrast to cells cultured in normal glucose; wherein, only basal phosphorylation was observed. The AVP-induced mTOR phosphorylation was inhibited by a PI3K inhibitor. Moreover, the AVP-induced mTOR activation inhibited autophagy and increased thymidine incorporation in cells grown in high glucose. This increase was abolished by rapamycin which inhibits the mTORC1 complex formation. Our results suggest that AVP stimulates mTOR phosphorylation by activating the PI3K/Akt signaling pathway and, subsequently, inhibits autophagy and raises cell proliferation in A-10 cells maintained in high glucose concentration.

  15. LXR Inhibits Proliferation of Human Breast Cancer Cells through the PI3K-Akt Pathway

    Directory of Open Access Journals (Sweden)

    Treska S. Hassan

    2015-05-01

    Full Text Available The oxysterol receptors, LXRs, have recently been shown to reduce cell and tumour growth in various model systems. Activation of LXRs could therefore provide a novel approach for treatment of cancers. Here we show that LXRβ is the main executor of the antiproliferative effect in human breast cancer cells. LXR inhibits the activation of growth factor-induced triggering of the PI3K-Akt pathway. Phosphorylation of several protein kinases in this pathway, including Akt and the PI3K itself, is reduced upon activation of LXR. Both mRNA and protein expression levels of the PTEN and PHLPPL protein phosphatases were induced by LXR and the amount of the second messenger PIP3 reduced—a pivotal activator signalling molecule in the PI3K. This suggest that the intracellular signalling cascade mediating proliferative cues from growth factors is the responsible mechanisms underlying the antiproliferative effects of LXR in human breast cancer cells. This provides novel and in-depth insights of how LXR works in cancer cells where the LXRs control the activity of intracellular signalling cascades that regulate proliferation.

  16. The MUC1 oncomucin regulates pancreatic cancer cell biological properties and chemoresistance. Implication of p42–44 MAPK, Akt, Bcl-2 and MMP13 pathways

    Energy Technology Data Exchange (ETDEWEB)

    Tréhoux, Solange; Duchêne, Bélinda; Jonckheere, Nicolas; Van Seuningen, Isabelle, E-mail: isabelle.vanseuningen@inserm.fr

    2015-01-16

    Highlights: • Loss of MUC1 decreases proliferation and tumor growth via β-catenin and p42–44 MAPK. • Inhibition of MUC1 decreases cell migration and invasion through MMP13. • Loss of MUC1 decreases survival and increases apoptosis via Akt and Bcl-2 pathways. • Loss of MUC1 sensitizes cells to gemcitabine and 5-Fluorouracil chemotherapeutic drugs. - Abstract: MUC1 is an oncogenic mucin overexpressed in several epithelial cancers, including pancreatic ductal adenocarcinoma, and is considered as a potent target for cancer therapy. To this aim, we undertook to study MUC1 biological effects on pancreatic cancer cells and identify pathways mediating these effects. Our in vitro experiments indicate that inhibiting MUC1 expression decreases cell proliferation, cell migration and invasion, cell survival and increases cell apoptosis. Moreover, lack of MUC1 in these cells profoundly altered their sensitivity to gemcitabine and 5-Fluorouracil chemotherapeutic drugs. In vivo MUC1-KD cell xenografts in SCID mice grew slower. Altogether, we show that MUC1 oncogenic mucin alters proliferation, migration, and invasion properties of pancreatic cancer cells and that these effects are mediated by p42–44 MAPK, Akt, Bcl-2 and MMP13 pathways.

  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. Activation of PI3K/Akt and ERK signaling pathways antagonized sinomenine-induced lung cancer cell apoptosis.

    Science.gov (United States)

    Zhou, Liping; Luan, Hong; Liu, Qingpeng; Jiang, Tingshu; Liang, Hongyuan; Dong, Xihua; Shang, Hong

    2012-05-01

    Sinomenine (SIN) is a bioactive component derived from a Chinese medicinal plant. Our previous studies demonstrated that SIN has cytotoxic effects on human lung cancer cells. However, the antitumor molecular mechanisms of SIN have yet to be elucidated in detail. In the present study, we further explored the effects of SIN on NCI-H460 human lung cancer cell viability and apoptosis and investigated the regulation and function of PI3K/Akt and ERK signaling pathways during SIN-induced apoptosis in various lung cancer cell lines. NCI-H460 cells were incubated with 200 µg/ml SIN for the indicated times (0, 24, 48 or 72 h). Cell viability was assessed by MTT assay. Akt, p-Akt, ERK1/2 and p-ERK1/2 protein levels were detected by western blotting, respectively. Two different selective inhibitors (LY294002 for the PI3K pathway; PD98059 for the MEK/ERK pathway) were used to characterize the relative roles of PI3K/Akt and ERK in SIN-induced apoptosis. Apoptosis was determined by flow cytometry. SIN inhibited the proliferation of NCI-H460 cells in a time-dependent manner, which was accompanied with significant activation of pAkt and pERK. LY294002 and PD98059 both significantly increased SIN-induced apoptosis in NCI-H460, NCI-H226 and NCI-H522 cells. Our findings suggest that the activation of the PI3K/Akt and ERK signaling pathways antagonize SIN-induced lung cancer cell apoptosis and molecules that inhibit these pathways should potentiate the effects of SIN. This study represents a significant step forward in our understanding of the signal transduction pathways associated with the apoptosis elicited by SIN. PMID:22367396

  19. Characterization of AKT independent effects of the synthetic AKT inhibitors SH-5 and SH-6 using an integrated approach combining transcriptomic profiling and signaling pathway perturbations

    International Nuclear Information System (INIS)

    Signal transduction processes mediated by phosphatidyl inositol phosphates affect a broad range of cellular processes such as cell cycle progression, migration and cell survival. The protein kinase AKT is one of the major effectors in this signaling network. Chronic AKT activation contributes to oncogenic transformation and tumor development. Therefore, analogs of phosphatidyl inositol phosphates (PIAs) were designed as new small drugs to block AKT activity for cancer treatment. Here we characterize the biological effects of the PIAs SH-5 and SH-6 in colorectal cancer cell lines. Serum-starved or serum-supplemented human colorectal cancer cell lines SW480, HT29 and HCT116 were exposed to SH-5 and SH-6. AKT activation was determined by western blotting. Cell viability was assessed using a colorimetric XTT-based assay, apoptosis and cell cycle changes were monitored by FACS analysis. The dynamics of cell morphology alterations was evaluated by confocal and time-lapse microscopy. Transcriptional changes due to inhibitor treatment were analyzed using Affymetrix HG-U133A microarrays and RT-PCR. While the PIAs clearly reduce AKT phosphorylation in serum starved cells, we did not observe a significant reduction under serum supplemented conditions, giving us the opportunity to analyze AKT independent effects of these compounds. Both inhibitors induce broadly the same morphological alterations, in particular changes in cell shape and formation of intracellular vesicles. Moreover, we observed the induction of binucleated cells specifically in the SW480 cell line. Gene expression analysis revealed transcriptional alterations, which are mostly cell line specific. In accordance to the phenotype we found a gene group associated with mitosis and spindle organization down regulated in SW480 cells, but not in the other cell lines. A bioinformatics analysis using the Connectivity Map linked the gene expression pattern of the inhibitor treated SW480 cells to PKC signaling. Using

  20. Roles of the RAF/MEK/ERK and PI3K/PTEN/AKT pathways in malignant transformation and drug resistance.

    Science.gov (United States)

    McCubrey, James A; Steelman, Linda S; Abrams, Steven L; Lee, John T; Chang, Fumin; Bertrand, Fred E; Navolanic, Patrick M; Terrian, David M; Franklin, Richard A; D'Assoro, Antonio B; Salisbury, Jeffrey L; Mazzarino, Maria Clorinda; Stivala, Franca; Libra, Massimo

    2006-01-01

    The Ras/Raf/MEK/ERK and PI3K/PTEN/AKT signaling cascades play critical roles in the transmission of signals from growth factor receptors to regulate gene expression and prevent apoptosis. Components of these pathways are mutated or aberrantly expressed in human cancer (e.g., Ras, B-Raf, PI3K, PTEN, Akt). Also, mutations occur at genes encoding upstream receptors (e.g., EGFR and Flt-3) and chimeric chromosomal translocations (e.g., BCR-ABL) which transmit their signals through these cascades. These pathways interact with each other to regulate growth and in some cases tumorigenesis. For example, in some cells, PTEN mutation may contribute to suppression of the Raf/MEK/ERK cascade due to the ability of elevated activated Akt levels to phosphorylate and inactivate Raf-1. We have investigated the genetic structures and functional roles of these two signaling pathways in the malignant transformation and drug resistance of hematopoietic, breast and prostate cancer cells. Although both of these pathways are commonly thought to have anti-apoptotic and drug resistance effects on cells, they display different cell-lineage-specific effects. Induced Raf expression can abrogate the cytokine dependence of certain hematopoietic cell lines (FDC-P1 and TF-1), a trait associated with tumorigenesis. In contrast, expression of activated PI3K or Akt does not abrogate the cytokine dependence of these hematopoietic cell lines, but does have positive effects on cell survival. However, activated PI3K and Akt can synergize with activated Raf to abrogate the cytokine dependence of another hematopoietic cell line (FL5.12) which is not transformed by activated Raf expression by itself. Activated Raf and Akt also confer a drug-resistant phenotype to these cells. Raf is more associated with proliferation and the prevention of apoptosis while Akt is more associated with the long-term clonogenicity. In breast cancer cells, activated Raf conferred resistance to the chemotherapeutic drugs

  1. Blood glucose fluctuation accelerates renal injury involved to inhibit the AKT signaling pathway in diabetic rats.

    Science.gov (United States)

    Ying, Changjiang; Zhou, Xiaoyan; Chang, Zhenzhen; Ling, Hongwei; Cheng, Xingbo; Li, Wei

    2016-07-01

    Blood glucose fluctuation is associated with diabetic nephropathy. However, the mechanism by which blood glucose fluctuation accelerates renal injury is not fully understood. The aim of the present study was to assess the effects of blood glucose fluctuation on diabetic nephropathy in rats and investigate its underlying mechanism. Diabetes in the rats was induced by a high sugar, high-fat diet, and a single dose of STZ (35 mg/kg)-injected intraperitoneally. Unstable blood sugar models were induced by subcutaneous insulin injection and intravenous glucose injection alternately. Body weight, glycosylated hemoglobin A1c (HbAlc), blood urea nitrogen (BUN), serum creatinine (Scr), and Creatinine clearance (Ccr) were assessed. T-SOD activity and MDA level were measured by assay kit. Change in renal tissue ultrastructure was observed by light microscopy and electron microscopy. Phosphorylated ser/thr protein kinase (p-AKT) (phosphor-Ser473), phosphorylated glycogen synthase kinase-3 beta (p-GSK-3β) (phosphor-Ser9), Bcl-2-associated X protein (BAX), B cell lymphoma/leukemia 2 (BCL-2), and cleaved-cysteinyl aspartate-specific proteinase-3 (caspase-3) levels were detected by immunohistochemistry and Western blot. We observed that BUN and Scr were increased in diabetic rats, and Ccr was decreased. Furthermore, blood glucose fluctuations could exacerbate the Ccr changes. Renal tissue ultrastructure was also seriously injured by glucose variability in diabetic rats. In addition, glucose fluctuation increased the oxidative stress of renal tissue. Moreover, fluctuating blood glucose decreased p-AKT level and BCL-2, and increased p-GSK-3β, BAX, cleaved-caspase-3 levels, and ratio of BAX/BCL-2 in the kidneys of diabetic rats. In conclusion, these results suggest that blood glucose fluctuation accelerated renal injury is due, at least in part to its oxidative stress promoting and inhibiting the AKT signaling pathway in diabetic rats. PMID:26860515

  2. Propolis augments apoptosis induced by butyrate via targeting cell survival pathways.

    Directory of Open Access Journals (Sweden)

    Eric Drago

    Full Text Available Diet is one of the major lifestyle factors affecting incidence of colorectal cancer (CC, and despite accumulating evidence that numerous diet-derived compounds modulate CC incidence, definitive dietary recommendations are not available. We propose a strategy that could facilitate the design of dietary supplements with CC-preventive properties. Thus, nutrient combinations that are a source of apoptosis-inducers and inhibitors of compensatory cell proliferation pathways (e.g., AKT signaling may produce high levels of programmed death in CC cells. Here we report the combined effect of butyrate, an apoptosis inducer that is produced through fermentation of fiber in the colon, and propolis, a honeybee product, on CC cells. We established that propolis increases the apoptosis of CC cells exposed to butyrate through suppression of cell survival pathways such as the AKT signaling. The programmed death of CC cells by combined exposure to butyrate and propolis is further augmented by inhibition of the JNK signaling pathway. Analyses on the contribution of the downstream targets of JNK signaling, c-JUN and JAK/STAT, to the apoptosis of butyrate/propolis-treated CC cells ascertained that JAK/STAT signaling has an anti-apoptotic role; whereas, the role of cJUN might be dependent upon regulatory cell factors. Thus, our studies ascertained that propolis augments apoptosis of butyrate-sensitive CC cells and re-sensitizes butyrate-resistant CC cells to apoptosis by suppressing AKT signaling and downregulating the JAK/STAT pathway. Future in vivo studies should evaluate the CC-preventive potential of a dietary supplement that produces high levels of colonic butyrate, propolis, and diet-derived JAK/STAT inhibitors.

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

    Science.gov (United States)

    Sun, Peng; Wei, Sheng; Wei, Xia; Wang, Jieqiong; Zhang, Yuanyuan; Qiao, Mingqi; Wu, Jibiao

    2016-01-01

    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. PMID:27057362

  4. Neurotrophic effects of a cyanine dye via the PI3K-Akt pathway: attenuation of motor discoordination and neurodegeneration in an ataxic animal model.

    Directory of Open Access Journals (Sweden)

    Hitomi Ohta

    Full Text Available BACKGROUND: Neurotrophic factors may be future therapeutic agents for neurodegenerative disease. In the screening of biologically active molecules for neurotrophic potency, we found that a photosensitizing cyanine dye, NK-4, had remarkable neurotrophic activities and was a potent radical scavenger. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we evaluated the effect of NK-4 on the protection of neurons against oxidative damage and investigated the associated intracellular signaling pathways. Subsequently, we evaluated the effect of NK-4 in an animal model of neurodegeneration. In vitro, NK-4 showed dose-dependent protection of PC12 cells from toxicity induced by oxidative stress caused by hydrogen peroxide (H(2O(2 or 6-hydroxydopamine (6-OHDA. Comparison of extracellular signal-regulated kinase signaling pathways between treatment with NK-4 and nerve growth factor (NGF using K252a, an inhibitor of the NGF receptor TrkA, revealed that NK-4 activity occurs independently of NGF receptors. LY294002, a phosphatidylinositol 3-kinase (PI3K inhibitor, blocked the protective effect of NK-4, and NK-4 caused activation of Akt/protein kinase B, a downstream effector of PI3K. These results suggest that the neuroprotective effects of NK-4 are mediated by the PI3K-Akt signaling pathway. NK-4 treatment also attenuated stress-induced activation of SAPK/JNK, which suggests that NK-4 activates a survival signaling pathway and inhibits stress-activated apoptotic pathways independently of the TrkA receptor in neuronal cells. In vivo, administration of NK-4 improved motor coordination in genetic ataxic hamsters, as assessed by rota-rod testing. Histological analysis showed that cerebellar atrophy was significantly attenuated by NK-4 treatment. Notably, the Purkinje cell count in the treated group was threefold higher than that in the vehicle group. CONCLUSIONS/SIGNIFICANCE: These results suggest that NK-4 is a potential agent for therapy for neurodegenerative

  5. Hepatic Stellate Cell Coculture Enables Sorafenib Resistance in Huh7 Cells through HGF/c-Met/Akt and Jak2/Stat3 Pathways

    Directory of Open Access Journals (Sweden)

    Weibo Chen

    2014-01-01

    Full Text Available Purpose. Tumor microenvironment confers drug resistance to kinase inhibitors by increasing RKT ligand levels that result in the activation of cell-survival signaling including PI3K and MAPK signals. We assessed whether HSC-LX2 coculture conferred sorafenib resistance in Huh7 and revealed the mechanism underlying the drug resistance. Experimental Design. The effect of LX2 on sorafenib resistance was determined by coculture system with Huh7 cells. The rescue function of LX2 supernatants was assessed by MTT assay and fluorescence microscopy. The underlying mechanism was tested by administration of pathway inhibitors and manifested by Western blotting. Results. LX2 coculture significantly induced sorafenib resistance in Huh7 by activating p-Akt that led to reactivation of p-ERK. LX2 secreted HGF into the culture medium that triggered drug resistance, and exogenous HGF could also induce sorafenib resistance. The inhibition of p-Akt blocked sorafenib resistance caused by LX2 coculture. Increased phosphorylation of Jak2 and Stat3 was also detected in LX2 cocultured Huh7 cells. The Jak inhibitor tofacitinib reversed sorafenib resistance by blocking Jak2 and Stat3 activation. The combined administration of sorafenib and p-Stat3 inhibitor S3I-201 augmented induced apoptosis even in the presence of sorafenib resistance. Conclusions. HSC-LX2 coculture induced sorafenib resistance in Huh7 through multiple pathways: HGF/c-Met/Akt pathway and Jak2/Stat3 pathway. A combined administration of sorafenib and S3I-201 was able to augment sorafenib-induced apoptosis even in the presence of LX2 coculture.

  6. CHIP promotes thyroid cancer proliferation via activation of the MAPK and AKT pathways.

    Science.gov (United States)

    Zhang, Li; Liu, Lianyong; He, Xiaohua; Shen, Yunling; Liu, Xuerong; Wei, Jing; Yu, Fang; Tian, Jianqing

    2016-08-26

    The carboxyl terminus of Hsp70-interacting protein (CHIP) is a U box-type ubiquitin ligase that plays crucial roles in various biological processes, including tumor progression. To date, the functional mechanism of CHIP in thyroid cancer remains unknown. Here, we obtained evidence of upregulation of CHIP in thyroid cancer tissues and cell lines. CHIP overexpression markedly enhanced thyroid cancer cell viability and colony formation in vitro and accelerated tumor growth in vivo. Conversely, CHIP knockdown impaired cell proliferation and tumor growth. Notably, CHIP promoted cell growth through activation of MAPK and AKT pathways, subsequently decreasing p27 and increasing cyclin D1 and p-FOXO3a expression. Our findings collectively indicate that CHIP functions as an oncogene in thyroid cancer, and is therefore a potential therapeutic target for this disease. PMID:27342662

  7. CHIP promotes thyroid cancer proliferation via activation of the MAPK and AKT pathways.

    Science.gov (United States)

    Zhang, Li; Liu, Lianyong; He, Xiaohua; Shen, Yunling; Liu, Xuerong; Wei, Jing; Yu, Fang; Tian, Jianqing

    2016-08-26

    The carboxyl terminus of Hsp70-interacting protein (CHIP) is a U box-type ubiquitin ligase that plays crucial roles in various biological processes, including tumor progression. To date, the functional mechanism of CHIP in thyroid cancer remains unknown. Here, we obtained evidence of upregulation of CHIP in thyroid cancer tissues and cell lines. CHIP overexpression markedly enhanced thyroid cancer cell viability and colony formation in vitro and accelerated tumor growth in vivo. Conversely, CHIP knockdown impaired cell proliferation and tumor growth. Notably, CHIP promoted cell growth through activation of MAPK and AKT pathways, subsequently decreasing p27 and increasing cyclin D1 and p-FOXO3a expression. Our findings collectively indicate that CHIP functions as an oncogene in thyroid cancer, and is therefore a potential therapeutic target for this disease.

  8. Curcumin Attenuated Bupivacaine-Induced Neurotoxicity in SH-SY5Y Cells Via Activation of the Akt Signaling Pathway.

    Science.gov (United States)

    Fan, You-Ling; Li, Heng-Chang; Zhao, Wei; Peng, Hui-Hua; Huang, Fang; Jiang, Wei-Hang; Xu, Shi-Yuan

    2016-09-01

    Bupivacaine is widely used for regional anesthesia, spinal anesthesia, and pain management. However, bupivacaine could cause neuronal injury. Curcumin, a low molecular weight polyphenol, has a variety of bioactivities and may exert neuroprotective effects against damage induced by some stimuli. In the present study, we tested whether curcumin could attenuate bupivacaine-induced neurotoxicity in SH-SY5Y cells. Cell injury was evaluated by examining cell viability, mitochondrial damage and apoptosis. We also investigated the levels of activation of the Akt signaling pathway and the effect of Akt inhibition by triciribine on cell injury following bupivacaine and curcumin treatment. Our findings showed that the bupivacaine treatment could induce neurotoxicity. Pretreatment of the SH-SY5Y cells with curcumin significantly attenuated bupivacaine-induced neurotoxicity. Interestingly, the curcumin treatment increased the levels of Akt phosphorylation. More significantly, the pharmacological inhibition of Akt abolished the cytoprotective effect of curcumin against bupivacaine-induced cell injury. Our data suggest that pretreating SH-SY5Y cells with curcumin provides a protective effect on bupivacaine-induced neuronal injury via activation of the Akt signaling pathway. PMID:27233246

  9. Piperlongumine promotes autophagy via inhibition of Akt/mTOR signalling and mediates cancer cell death

    OpenAIRE

    Makhov, P; Golovine, K.; Teper, E.; Kutikov, A.; Mehrazin, R.; Corcoran, A; A. Tulin; Uzzo, R G; Kolenko, V M

    2014-01-01

    Background: The Akt/mammalian target of rapamycin (mTOR) signalling pathway serves as a critical regulator of cellular growth, proliferation and survival. Akt aberrant activation has been implicated in carcinogenesis and anticancer therapy resistance. Piperlongumine (PL), a natural alkaloid present in the fruit of the Long pepper, is known to exhibit notable anticancer effects. Here we investigate the impact of PL on Akt/mTOR signalling. Methods: We examined Akt/mTOR signalling in cancer cell...

  10. Heat Stress-Induced PI3K/mTORC2-Dependent AKT Signaling Is a Central Mediator of Hepatocellular Carcinoma Survival to Thermal Ablation Induced Heat Stress.

    Science.gov (United States)

    Thompson, Scott M; Callstrom, Matthew R; Jondal, Danielle E; Butters, Kim A; Knudsen, Bruce E; Anderson, Jill L; Lien, Karen R; Sutor, Shari L; Lee, Ju-Seog; Thorgeirsson, Snorri S; Grande, Joseph P; Roberts, Lewis R; Woodrum, David A

    2016-01-01

    Thermal ablative therapies are important treatment options in the multidisciplinary care of patients with hepatocellular carcinoma (HCC), but lesions larger than 2-3 cm are plagued with high local recurrence rates and overall survival of these patients remains poor. Currently no adjuvant therapies exist to prevent local HCC recurrence in patients undergoing thermal ablation. The molecular mechanisms mediating HCC resistance to thermal ablation induced heat stress and local recurrence remain unclear. Here we demonstrate that the HCC cells with a poor prognostic hepatic stem cell subtype (Subtype HS) are more resistant to heat stress than HCC cells with a better prognostic hepatocyte subtype (Subtype HC). Moreover, sublethal heat stress rapidly induces phosphoinositide 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) dependent-protein kinase B (AKT) survival signaling in HCC cells in vitro and at the tumor ablation margin in vivo. Conversely, inhibition of PI3K/mTOR complex 2 (mTORC2)-dependent AKT phosphorylation or direct inhibition of AKT function both enhance HCC cell killing and decrease HCC cell survival to sublethal heat stress in both poor and better prognostic HCC subtypes while mTOR complex 1 (mTORC1)-inhibition has no impact. Finally, we showed that AKT isoforms 1, 2 and 3 are differentially upregulated in primary human HCCs and that overexpression of AKT correlates with worse tumor biology and pathologic features (AKT3) and prognosis (AKT1). Together these findings define a novel molecular mechanism whereby heat stress induces PI3K/mTORC2-dependent AKT survival signaling in HCC cells and provide a mechanistic rationale for adjuvant AKT inhibition in combination with thermal ablation as a strategy to enhance HCC cell killing and prevent local recurrence, particularly at the ablation margin. PMID:27611696

  11. Mutational analysis of PI3K/AKT and RAS/RAF pathway activation in malignant salivary gland tumours with a new mutation of PIK3CA.

    Science.gov (United States)

    Shalmon, B; Drendel, M; Wolf, M; Hirshberg, A; Cohen, Y

    2016-06-01

    The phosphoinositide 3-kinase (PIK3)/v-akt murine thymoma (AKT) oncogene pathway and the RAS/RAF pathway are involved in regulating the signalling of multiple biological processes, including apoptosis, metabolism, cell proliferation, and cell growth. Mutations in the genes within these pathways are frequently found in several tumours. The aim of this study was to investigate the frequency of mutations in the PIK3CA, BRAF, and KRAS genes in cases of malignant salivary gland tumours. Mutational analysis of the PIK3CA, KRAS, and BRAF genes was performed by direct sequencing of material from 21 patients with malignant salivary gland tumours who underwent surgery between 1992 and 2001. No mutations were found in the KRAS exon 2, BRAF exon 15, or PIK3CA exon 9 genes. However, an unpublished mutation of the PIK3CA gene in exon 20 (W1051 stop mutation) was found in one case of adenocarcinoma NOS. The impact of this mutation on the biological behaviour of the tumour has yet to be explored, however the patient with adenocarcinoma NOS harbouring this mutation has survived for over 20 years following surgery despite a high stage at presentation. Further studies with more homogeneous patient cohorts are needed to address whether this mutation reflects a different clinical presentation and may benefit from targeted treatment strategies. PMID:26811072

  12. eIF4B is a convergent target and critical effector of oncogenic Pim and PI3K/Akt/mTOR signaling pathways in Abl transformants.

    Science.gov (United States)

    Chen, Ke; Yang, Jianling; Li, Jianning; Wang, Xuefei; Chen, Yuhai; Huang, Shile; Chen, Ji-Long

    2016-03-01

    Activation of eIF4B correlates with Abl-mediated cellular transformation, but the precise mechanisms are largely unknown. Here we show that eIF4B is a convergent substrate of JAK/STAT/Pim and PI3K/Akt/mTOR pathways in Abl transformants. Both pathways phosphorylated eIF4B in Abl-transformed cells, and such redundant regulation was responsible for the limited effect of single inhibitor on Abl oncogenicity. Persistent inhibition of one signaling pathway induced the activation of the other pathway and thereby restored the phosphorylation levels of eIF4B. Simultaneous inhibition of the two pathways impaired eIF4B phosphorylation more effectively, and synergistically induced apoptosis in Abl transformed cells and inhibited the growth of engrafted tumors in nude mice. Similarly, the survival of Abl transformants exhibited a higher sensitivity to the pharmacological inhibition, when combined with the shRNA-based silence of the other pathway. Interestingly, such synergy was dependent on the phosphorylation status of eIF4B on Ser422, as overexpression of eIF4B phosphomimetic mutant S422E in the transformants greatly attenuated the synergistic effects of these inhibitors on Abl oncogenicity. In contrast, eIF4B knockdown sensitized Abl transformants to undergo apoptosis induced by the combined blockage. Collectively, the results indicate that eIF4B integrates the signals from Pim and PI3K/Akt/mTOR pathways in Abl-expressing leukemic cells, and is a promising therapeutic target for such cancers. PMID:26848623

  13. Anti-malarial drug artesunate attenuates experimental allergic asthma via inhibition of the phosphoinositide 3-kinase/Akt pathway.

    Directory of Open Access Journals (Sweden)

    Chang Cheng

    Full Text Available BACKGROUND: Phosphoinositide 3-kinase (PI3K/Akt pathway is linked to the development of asthma. Anti-malarial drug artesunate is a semi-synthetic derivative of artemisinin, the principal active component of a medicinal plant Artemisia annua, and has been shown to inhibit PI3K/Akt activity. We hypothesized that artesunate may attenuate allergic asthma via inhibition of the PI3K/Akt signaling pathway. METHODOLOGY/PRINCIPAL FINDINGS: Female BALB/c mice sensitized and challenged with ovalbumin (OVA developed airway inflammation. Bronchoalveolar lavage fluid was assessed for total and differential cell counts, and cytokine and chemokine levels. Lung tissues were examined for cell infiltration and mucus hypersecretion, and the expression of inflammatory biomarkers. Airway hyperresponsiveness was monitored by direct airway resistance analysis. Artesunate dose-dependently inhibited OVA-induced increases in total and eosinophil counts, IL-4, IL-5, IL-13 and eotaxin levels in bronchoalveolar lavage fluid. It attenuated OVA-induced lung tissue eosinophilia and airway mucus production, mRNA expression of E-selectin, IL-17, IL-33 and Muc5ac in lung tissues, and airway hyperresponsiveness to methacholine. In normal human bronchial epithelial cells, artesunate blocked epidermal growth factor-induced phosphorylation of Akt and its downstream substrates tuberin, p70S6 kinase and 4E-binding protein 1, and transactivation of NF-κB. Similarly, artesunate blocked the phosphorylation of Akt and its downstream substrates in lung tissues from OVA-challenged mice. Anti-inflammatory effect of artesunate was further confirmed in a house dust mite mouse asthma model. CONCLUSION/SIGNIFICANCE: Artesunate ameliorates experimental allergic airway inflammation probably via negative regulation of PI3K/Akt pathway and the downstream NF-κB activity. These findings provide a novel therapeutic value for artesunate in the treatment of allergic asthma.

  14. Lithium protects against methamphetamine-induced neurotoxicity in PC12 cells via Akt/GSK3β/mTOR pathway

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jintao; Zhu, Dexiao; Zhang, Jing; Li, Guibao [Department of Anatomy, School of Medicine, Shandong University, Jinan, Shandong, 250012 (China); Liu, Zengxun [Department of Psychiatry, School of Medicine, Shandong University, Jinan, Shandong, 250012 China (China); Sun, Jinhao, E-mail: sunjinhao@gmail.com [Department of Anatomy, School of Medicine, Shandong University, Jinan, Shandong, 250012 (China)

    2015-09-25

    Methamphetamine (MA) is neurotoxic, especially in dopaminergic neurons. Long-lasting exposure to MA causes psychosis and increases the risk of Parkinson's disease. Lithium (Li) is a known mood stabilizer and has neuroprotective effects. Previous studies suggest that MA exposure decreases the phosphorylation of Akt/GSK3β pathway in vivo, whereas Li facilitates the phosphorylation of Akt/GSK3β pathway. Moreover, GSK3β and mTOR are implicated in the locomotor sensitization induced by psychostimulants and mTOR plays a critical role in MA induced toxicity. However, the effect of MA on Akt/GSK3β/mTOR pathway has not been fully investigated in vitro. Here, we found that MA exposure significantly dephosphorylated Akt/GSK3β/mTOR pathway in PC12 cells. In addition, Li remarkably attenuated the dephosphorylation effect of MA exposure on Akt/GSK3β/mTOR pathway. Furthermore, Li showed obvious protective effects against MA toxicity and LY294002 (Akt inhibitor) suppressed the protective effects of Li. Together, MA exposure dephosphorylates Akt/GSK3β/mTOR pathway in vitro, while lithium protects against MA-induced neurotoxicity via phosphorylation of Akt/GSK3β/mTOR pathway. - Highlights: • Lithium protects against methamphetamine-induced neurotoxicity in vitro. • Methamphetamine exposure dephosphorylates Akt/GSK3β/mTOR pathway. • Lithium attenuates methamphetamine-induced toxicity via phosphorylating Akt/GSK3β/mTOR pathway.

  15. Sericin can reduce hippocampal neuronal apoptosis by activating the Akt signal transduction pathway in a rat model of diabetes mellitus

    Institute of Scientific and Technical Information of China (English)

    Zhihong Chen; Yaqiang He; Chengjun Song; Zhijun Dong; Zhejun Su; Jingfeng Xue

    2012-01-01

    In the present study, a rat model of type 2 diabetes mellitus was established by continuous peritoneal injection of streptozotocin. Following intragastric perfusion of sericin for 35 days, blood glucose levels significantly reduced, neuronal apoptosis in the hippocampal CA1 region decreased, hippocampal phosphorylated Akt and nuclear factor kappa B expression were enhanced, but Bcl-xL/Bcl-2 associated death promoter expression decreased. Results demonstrated that sericin can reduce hippocampal neuronal apoptosis in a rat model of diabetes mellitus by regulating abnormal changes in the Akt signal transduction pathway.

  16. 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. PMID:26342198

  17. 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.

  18. Advance in PI3K/Akt/mTOR Signaling Pathway and Its Relationship with Prost ate Cancer Research%PI3K/Akt/mTOR信号传导通路与前列腺癌关系的研究进展

    Institute of Scientific and Technical Information of China (English)

    贾艳菊; 季晖

    2015-01-01

    前列腺癌是威胁中老年男性健康的常见肿瘤,成为男性癌症死因的第二位。 PI3K/Akt/mTOR信号通路能够通过维持细胞生存、抑制细胞凋亡、促进细胞周期运行及血管生成等促进前列腺癌病程发展。本文综合国内外文献,阐述PI3K/Akt/mTOR信号通路在前列腺癌发生发展中的作用以及和通路相关的药物治疗进展。%Prostate cancer is the most common cancer which threatens middle and old age men's health and is the second leading cause of cancer-related mortality in men. PI3K/Akt/mTOR signaling pathway promotes the progression of prostate cancer through maintaining cell survival, inhibiting cell apoptosis, accelerating cell cycle and angiogenesis. Here, we review the role of the PI3K/Akt/mTOR pathway in prostate cancer and discuss the potential use of pathway inhibitors in the evolving treatment landscape of prostate cancer.

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

    Energy Technology Data Exchange (ETDEWEB)

    Iqbal, Mohd S. [Department of Bio-Signal Analysis, Applied Medical Engineering Science, Graduate School of Medicine, Yamaguchi University, Ube, Yamaguchi 755-8505 (Japan); Enteric and Food Microbiology Laboratory, Laboratory Sciences Division, International Center for Diarrhoeal Disease Research, Bangladesh, P.O. Box 128, Dhaka 1000 (Bangladesh); Tsuyama, Naohiro [Department of Analytical Molecular Medicine and Devices, Division of Frontier Medical Science, Graduate School of Medical Sciences, Hiroshima University, Hiroshima, Hiroshima 734-8553 (Japan); Obata, Masanori [Department of Bio-Signal Analysis, Applied Medical Engineering Science, Graduate School of Medicine, Yamaguchi University, Ube, Yamaguchi 755-8505 (Japan); Ishikawa, Hideaki, E-mail: hishika@yamaguchi-u.ac.jp [Department of Bio-Signal Analysis, Applied Medical Engineering Science, Graduate School of Medicine, Yamaguchi University, Ube, Yamaguchi 755-8505 (Japan)

    2010-02-12

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

  20. Matrine inhibits proliferation and induces apoptosis of human colon cancer LoVo cells by inactivating Akt pathway.

    Science.gov (United States)

    Zhang, Shujun; Cheng, Binglin; Li, Hali; Xu, Wei; Zhai, Bo; Pan, Shangha; Wang, Lei; Liu, Ming; Sun, Xueying

    2014-01-01

    The present study has investigated the anti-tumor activity and the underlying mechanisms of matrine on human colon cancer LoVo cells. Matrine inhibited the proliferation of the cells in dose- and time-dependent manners. The concentration required for 50 % inhibition (IC50) was 1.15, 0.738, and 0.414 mg/ml, when cell were incubated with matrine for 24, 48, and 72 h, respectively. Matrine induced cell cycle arrest at G1 phase by downregulating cyclin D1 and upregulating p27 and p21. Matrine induced cell apoptosis by reducing the ratio of Bcl-2/Bax and increasing the activation of caspase-9 in a dose-dependent manner. Matrine displayed its anti-tumor activity by inactivating Akt, the upstream factor of the above proteins. Matrine significantly reduced the protein levels of pAkt, and increased the protein levels of other downstream factors, pBad and pGSK-3β. Specific inhibition of pAkt induced cell apoptosis, and synergized with matrine to inhibit the proliferation of LoVo cells; whereas activation of Akt neutralized the inhibitory effect of matrine on cell proliferation. The present study has demonstrated that matrine inhibits proliferation and induces apoptosis of human colon cancer LoVo cells by inactivating Akt pathway, indicating matrine may be a potential anti-cancer agent for colon cancer.

  1. 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

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

    OpenAIRE

    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 diabeti...

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

    Directory of Open Access Journals (Sweden)

    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.

  4. 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.

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

    International Nuclear Information System (INIS)

    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

  6. Neuroprotective Effects of Rhynchophylline Against Ischemic Brain Injury via Regulation of the Akt/mTOR and TLRs Signaling Pathways

    Directory of Open Access Journals (Sweden)

    Houcai Huang

    2014-07-01

    Full Text Available Rhynchophylline (Rhy is an alkaloid isolated from Uncaria which has long been recommended for the treatment of central nervous diseases. In our study, the neuroprotective effect of Rhy was investigated in a stroke model, namely permanent middle cerebral artery occlusion (pMCAO. Rats were injected intraperitoneally once daily for four consecutive days before surgery and then received one more injection after surgery. The protein and mRNA levels of p-Akt, p-mTOR, apoptosis-related proteins (p-BAD and cleaved caspase-3, TLR2/4/9, NF-κB, MyD88, BDNF and claudin-5 were examined. Following pMCAO, Rhy treatment not only ameliorated neurological deficits, infarct volume and brain edema, but also increased claudin-5 and BDNF expressions (p < 0.05. Moreover, Rhy could activate PI3K/Akt/mTOR signaling while inhibiting TLRs/NF-κB pathway. Wortmannin, a selective PI3K inhibitor, could abolish the neuroprotective effect of Rhy and reverse the increment in p-Akt, p-mTOR and p-BAD levels. In conclusion, we hypothesize that Rhy protected against ischemic damage, probably via regulating the Akt/mTOR pathway.

  7. Neuroprotective effects of rhynchophylline against ischemic brain injury via regulation of the Akt/mTOR and TLRs signaling pathways.

    Science.gov (United States)

    Huang, Houcai; Zhong, Rongling; Xia, Zhi; Song, Jie; Feng, Liang

    2014-01-01

    Rhynchophylline (Rhy) is an alkaloid isolated from Uncaria which has long been recommended for the treatment of central nervous diseases. In our study, the neuroprotective effect of Rhy was investigated in a stroke model, namely permanent middle cerebral artery occlusion (pMCAO). Rats were injected intraperitoneally once daily for four consecutive days before surgery and then received one more injection after surgery. The protein and mRNA levels of p-Akt, p-mTOR, apoptosis-related proteins (p-BAD and cleaved caspase-3), TLR2/4/9, NF-κB, MyD88, BDNF and claudin-5 were examined. Following pMCAO, Rhy treatment not only ameliorated neurological deficits, infarct volume and brain edema, but also increased claudin-5 and BDNF expressions (p < 0.05). Moreover, Rhy could activate PI3K/Akt/mTOR signaling while inhibiting TLRs/NF-κB pathway. Wortmannin, a selective PI3K inhibitor, could abolish the neuroprotective effect of Rhy and reverse the increment in p-Akt, p-mTOR and p-BAD levels. In conclusion, we hypothesize that Rhy protected against ischemic damage, probably via regulating the Akt/mTOR pathway. PMID:25079660

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

    Science.gov (United States)

    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. PMID:26883517

  9. Inhibition of the PI3K/Akt/mTOR Signaling Pathway in Diffuse Large B-Cell Lymphoma: Current Knowledge and Clinical Significance

    Directory of Open Access Journals (Sweden)

    Agata Majchrzak

    2014-09-01

    Full Text Available Diffuse large B-cell lymphoma (DLBCL is one of the most common non-Hodgkin lymphomas in adults. The disease is very heterogeneous in its presentation, that is DLBCL patients may differ from each other not only in regard to histology of tissue infiltration, clinical course or response to treatment, but also in respect to diversity in gene expression profiling. A growing body of knowledge on the biology of DLBCL, including abnormalities in intracellular signaling, has allowed the development of new treatment strategies, specifically directed against lymphoma cells. The phosphoinositide 3-kinase (PI3K/protein kinase B (Akt/mammalian target of rapamycin (mTOR signaling pathway plays an important role in controlling proliferation and survival of tumor cells in various types of malignancies, including DLBCL, and therefore it may be a promising target for therapeutic intervention. Currently, novel anticancer drugs are undergoing assessment in different phases of clinical trials in aggressive lymphomas, with promising outcomes. In this review we present a state of art review on various classes of small molecule inhibitors selectively involving PI3K/Akt/mTOR pathway and their clinical potential in this disease.

  10. Inhibition of the PI3K/Akt/mTOR signaling pathway in diffuse large B-cell lymphoma: current knowledge and clinical significance.

    Science.gov (United States)

    Majchrzak, Agata; Witkowska, Magdalena; Smolewski, Piotr

    2014-09-11

    Diffuse large B-cell lymphoma (DLBCL) is one of the most common non-Hodgkin lymphomas in adults. The disease is very heterogeneous in its presentation, that is DLBCL patients may differ from each other not only in regard to histology of tissue infiltration, clinical course or response to treatment, but also in respect to diversity in gene expression profiling. A growing body of knowledge on the biology of DLBCL, including abnormalities in intracellular signaling, has allowed the development of new treatment strategies, specifically directed against lymphoma cells. The phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway plays an important role in controlling proliferation and survival of tumor cells in various types of malignancies, including DLBCL, and therefore it may be a promising target for therapeutic intervention. Currently, novel anticancer drugs are undergoing assessment in different phases of clinical trials in aggressive lymphomas, with promising outcomes. In this review we present a state of art review on various classes of small molecule inhibitors selectively involving PI3K/Akt/mTOR pathway and their clinical potential in this disease.

  11. Combined inhibition of p38 and Akt signaling pathways abrogates cyclosporine A-mediated pathogenesis of aggressive skin SCCs

    Energy Technology Data Exchange (ETDEWEB)

    Arumugam, Aadithya; Walsh, Stephanie B.; Xu, Jianmin; Afaq, Farrukh [Department of Dermatology, University of Alabama at Birmingham, Birmingham, AL 35294-0019 (United States); Elmets, Craig A. [Department of Dermatology, University of Alabama at Birmingham, Birmingham, AL 35294-0019 (United States); Skin Diseases Research Center, University of Alabama at Birmingham, Birmingham, AL 35294 (United States); Athar, Mohammad, E-mail: mathar@uab.edu [Department of Dermatology, University of Alabama at Birmingham, Birmingham, AL 35294-0019 (United States); Skin Diseases Research Center, University of Alabama at Birmingham, Birmingham, AL 35294 (United States)

    2012-08-24

    Highlights: Black-Right-Pointing-Pointer p38 and Akt are the crucial molecular targets in the pathogenesis of SCCs in OTRs. Black-Right-Pointing-Pointer Combined inhibition of these targets diminished tumor growth by 90%. Black-Right-Pointing-Pointer Inhibition of these targets act through downregulating mTOR signaling pathway. -- Abstract: Non-melanoma skin cancers (NMSCs) are the most common neoplasm in organ transplant recipients (OTRs). These cancers are more invasive and metastatic as compared to those developed in normal cohorts. Previously, we have shown that immunosuppressive drug, cyclosporine A (CsA) directly alters tumor phenotype of cutaneous squamous cell carcinomas (SCCs) by activating TGF-{beta} and TAK1/TAB1 signaling pathways. Here, we identified novel molecular targets for the therapeutic intervention of these SCCs. We observed that combined blockade of Akt and p38 kinases-dependent signaling pathways in CsA-promoted human epidermoid carcinoma A431 xenograft tumors abrogated their growth by more than 90%. This diminution in tumor growth was accompanied by a significant decrease in proliferation and an increase in apoptosis. The residual tumors following the combined treatment with Akt inhibitor triciribine and p38 inhibitors SB-203580 showed significantly diminished expression of phosphorylated Akt and p38 and these tumors were less invasive and highly differentiated. Diminished tumor invasiveness was associated with the reduced epithelial-mesenchymal transition as ascertained by the enhanced E-cadherin and reduced vimentin and N-cadherin expression. Consistently, these tumors also manifested reduced MMP-2/9. The decreased p-Akt expression was accompanied by a significant reduction in p-mTOR. These data provide first important combinatorial pharmacological approach to block the pathogenesis of CsA-induced highly aggressive cutaneous neoplasm in OTRs.

  12. Combined inhibition of p38 and Akt signaling pathways abrogates cyclosporine A-mediated pathogenesis of aggressive skin SCCs

    International Nuclear Information System (INIS)

    Highlights: ► p38 and Akt are the crucial molecular targets in the pathogenesis of SCCs in OTRs. ► Combined inhibition of these targets diminished tumor growth by 90%. ► Inhibition of these targets act through downregulating mTOR signaling pathway. -- Abstract: Non-melanoma skin cancers (NMSCs) are the most common neoplasm in organ transplant recipients (OTRs). These cancers are more invasive and metastatic as compared to those developed in normal cohorts. Previously, we have shown that immunosuppressive drug, cyclosporine A (CsA) directly alters tumor phenotype of cutaneous squamous cell carcinomas (SCCs) by activating TGF-β and TAK1/TAB1 signaling pathways. Here, we identified novel molecular targets for the therapeutic intervention of these SCCs. We observed that combined blockade of Akt and p38 kinases-dependent signaling pathways in CsA-promoted human epidermoid carcinoma A431 xenograft tumors abrogated their growth by more than 90%. This diminution in tumor growth was accompanied by a significant decrease in proliferation and an increase in apoptosis. The residual tumors following the combined treatment with Akt inhibitor triciribine and p38 inhibitors SB-203580 showed significantly diminished expression of phosphorylated Akt and p38 and these tumors were less invasive and highly differentiated. Diminished tumor invasiveness was associated with the reduced epithelial–mesenchymal transition as ascertained by the enhanced E-cadherin and reduced vimentin and N-cadherin expression. Consistently, these tumors also manifested reduced MMP-2/9. The decreased p-Akt expression was accompanied by a significant reduction in p-mTOR. These data provide first important combinatorial pharmacological approach to block the pathogenesis of CsA-induced highly aggressive cutaneous neoplasm in OTRs.

  13. INPP4B reverses docetaxel resistance and epithelial-to-mesenchymal transition via the PI3K/Akt signaling pathway in prostate cancer.

    Science.gov (United States)

    Chen, Haiwen; Li, Hongliang; Chen, Qi

    2016-08-26

    Docetaxel efficiency in the therapy of prostate cancer (PCa) patients is limited due to the development of chemoresistance. Recent studies have implied a role of INPP4B in tumor chemoresistance, while the effects of INPP4B on docetaxel resistance in PCa have not been elucidated. In the present study, the docetaxel-resistant human PCa cell lines PC3-DR and DU-145-DR were established from the parental cell lines PC3 and DU-145, and the expression and role of INPP4B in docetaxel-resistant PCa cells were investigated. The results demonstrated that INPP4B expression was significantly downregulated in docetaxel-resistant cells. Overexpression of INPP4B increased the sensitivity to docetaxel and promoted cell apoptosis in PC3-DR and DU-145-DR cells. In addition, INPP4B overexpression downregulated the expression of the mesenchymal markers fibronectin, N-cadherin, and vimentin, and upregulated the expression level of the epithelial maker E-cadherin. Furthermore, INPP4B overexpression markedly inhibited the PI3K/Akt pathway. We also found that IGF-1, the inhibitor of PI3K/Akt, markedly blocked the change in EMT markers induced by overexpression of INPP4B, and reversed the resistance of PC3-DR and DU-145-DR cells to docetaxel, which is sensitized by Flag-INPP4B. In summary, the presented data indicate that INPP4B is crucial for docetaxel-resistant PCa cell survival, potentially by regulating EMT through the PI3K/Akt signaling pathway. PMID:27318090

  14. Orexin A Affects INS-1 Rat Insulinoma Cell Proliferation via Orexin Receptor 1 and the AKT Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Li Chen

    2013-01-01

    Full Text Available Our aim is to investigate the role of the AKT/PKB (protein kinase B signaling pathway acting via orexin receptor 1 (OX1R and the effects of orexin A (OXA on cell proliferation in the insulin-secreting beta-cell line (INS-1 cells. Rat INS-1 cells were exposed to different concentrations of OXA in vitro and treated with OX1R antagonist (SB334867, PI3K antagonist (wortmannin, AKT antagonist (PF-04691502, or negative control. INS-1 amount of cell proliferation, viability and apoptosis, insulin secretion, OX1R protein expression, caspase-3 activity, and AKT protein levels were determined. We report that OXA (10-10 to 10-6 M stimulates INS-1 cell proliferation and viability, reduces the proapoptotic activity of caspase-3 to protect against apoptotic cell death, and increases insulin secretion. Additionally, AKT phosphorylation was stimulated by OXA (10-10 to 10-6 M. However, the OX1R antagonist SB334867 (10-6 M, the PI3K antagonist wortmannin (10-8 M, the AKT antagonist PF-04691502 (10-6 M, or the combination of both abolished the effects of OXA to a certain extent. These results suggest that the upregulation of OXA-OX1R mediated by AKT activation may inhibit cell apoptosis and promote cell proliferation in INS-1 cells. This finding provides functional evidence of the biological actions of OXA in rat insulinoma cells.

  15. Orexin A Affects INS-1 Rat Insulinoma Cell Proliferation via Orexin Receptor 1 and the AKT Signaling Pathway

    Science.gov (United States)

    Chen, Li; Zhao, Yuyan; Zheng, Delu; Ju, Shujing; Shen, Yang; Guo, Lei

    2013-01-01

    Our aim is to investigate the role of the AKT/PKB (protein kinase B) signaling pathway acting via orexin receptor 1 (OX1R) and the effects of orexin A (OXA) on cell proliferation in the insulin-secreting beta-cell line (INS-1 cells). Rat INS-1 cells were exposed to different concentrations of OXA in vitro and treated with OX1R antagonist (SB334867), PI3K antagonist (wortmannin), AKT antagonist (PF-04691502), or negative control. INS-1 amount of cell proliferation, viability and apoptosis, insulin secretion, OX1R protein expression, caspase-3 activity, and AKT protein levels were determined. We report that OXA (10−10 to 10−6 M) stimulates INS-1 cell proliferation and viability, reduces the proapoptotic activity of caspase-3 to protect against apoptotic cell death, and increases insulin secretion. Additionally, AKT phosphorylation was stimulated by OXA (10−10 to 10−6 M). However, the OX1R antagonist SB334867 (10−6 M), the PI3K antagonist wortmannin (10−8 M), the AKT antagonist PF-04691502 (10−6 M), or the combination of both abolished the effects of OXA to a certain extent. These results suggest that the upregulation of OXA-OX1R mediated by AKT activation may inhibit cell apoptosis and promote cell proliferation in INS-1 cells. This finding provides functional evidence of the biological actions of OXA in rat insulinoma cells. PMID:24382962

  16. Early pregnancy modulates survival and apoptosis pathways in the corpus luteum in sheep.

    Science.gov (United States)

    Lee, JeHoon; Banu, Sakhila K; McCracken, John A; Arosh, Joe A

    2016-03-01

    The corpus luteum (CL) is a transient endocrine gland. Functional and structural demise of the CL allows a new estrous cycle. On the other hand, survival of CL and its secretion of progesterone are required for the establishment of pregnancy. Survival or apoptosis of the luteal cells is precisely controlled by interactions between survival and apoptosis pathways. Regulation of these cell signaling components during natural luteolysis and establishment of pregnancy is largely unknown in ruminants. The objective of the present study was to determine the regulation of survival and apoptosis signaling protein machinery in the CL on days 12, 14, and 16 of the estrous cycle and pregnancy in sheep. Results indicate that: i) expressions of p-ERK1/2, p-AKT, β-catenin, NFκB -p65, -p50, -p52, p-Src, p-β -arrestin, p-GSK3β, X-linked inhibitor of apoptosis protein (XIAP), and p-CREB proteins are suppressed during natural luteolysis; in contrast, their expressions are sustained or increased during establishment of pregnancy; ii) expressions of cleaved caspase-3, apoptosis inducing factor (AIF), c-Fos, c-Jun, and EGR-1 proteins are increased during natural luteolysis; in contrast, their expressions are decreased during establishment of pregnancy; and iii) expressions of Bcl-2, Bcl-XL, Bad, and Bax proteins are not modulated during natural luteolysis while expressions of Bcl2 and Bcl-XL proteins are increased during establishment of pregnancy in sheep. These proteomic changes are evident in both large and small luteal cells. These results together indicate that regression of the CL during natural luteolysis or survival of the CL during establishment of pregnancy is precisely controlled by distinct programmed suppression or activation of intraluteal cell survival and apoptosis pathways in sheep/ruminants. PMID:26585285

  17. Nitric oxide synthase and breast cancer: role of TIMP-1 in NO-mediated Akt activation.

    Directory of Open Access Journals (Sweden)

    Lisa A Ridnour

    Full Text Available Prediction of therapeutic response and cancer patient survival can be improved by the identification of molecular markers including tumor Akt status. A direct correlation between NOS2 expression and elevated Akt phosphorylation status has been observed in breast tumors. Tissue inhibitor matrix metalloproteinase-1 (TIMP-1 has been proposed to exert oncogenic properties through CD63 cell surface receptor pathway initiation of pro-survival PI3k/Akt signaling. We employed immunohistochemistry to examine the influence of TIMP-1 on the functional relationship between NOS2 and phosphorylated Akt in breast tumors and found that NOS2-associated Akt phosphorylation was significantly increased in tumors expressing high TIMP-1, indicating that TIMP-1 may further enhance NO-induced Akt pathway activation. Moreover, TIMP-1 silencing by antisense technology blocked NO-induced PI3k/Akt/BAD phosphorylation in cultured MDA-MB-231 human breast cancer cells. TIMP-1 protein nitration and TIMP-1/CD63 co-immunoprecipitation was observed at NO concentrations that induced PI3k/Akt/BAD pro-survival signaling. In the survival analysis, elevated tumor TIMP-1 predicted poor patient survival. This association appears to be mainly restricted to tumors with high NOS2 protein. In contrast, TIMP-1 did not predict poor survival in patient tumors with low NOS2 expression. In summary, our findings suggest that tumors with high TIMP-1 and NOS2 behave more aggressively by mechanisms that favor Akt pathway activation.

  18. The AKT-mTOR signalling pathway in kidney cancer tissues

    Science.gov (United States)

    Spirina, L. V.; Usynin, Y. A.; Kondakova, I. V.; Yurmazov, Z. A.; Slonimskaya, E. M.; Kolegova, E. S.

    2015-11-01

    An increased expression of phospho-AKT, m-TOR, glycogen regulator GSK-3-beta and transcription inhibitor 4E-BP1 was observed in kidney cancer tissues. Tumor size growth was associated with a high level of c-Raf and low content of phospho-m-TOR. Cancer metastasis development led to a decreased PTEN and phospho-AKT expression.

  19. Cadmium Activates Reactive Oxygen Species-dependent AKT/mTOR and Mitochondrial Apoptotic Pathways in Neuronal Cells

    Institute of Scientific and Technical Information of China (English)

    YUAN Yan; BIAN Jian Chun; LIU Zong Ping; WANG Yi; HU Fei Fei; JIANG Chen Yang; ZHANG Ya Jing; YANG Jin Long; ZHAO Shi Wen; GU Jian Hong; LIU Xue Zhong

    2016-01-01

    ObjectiveTo examine the role of Cd-induced reactive oxygen species (ROS) generation in the apoptosis of neuronal cells. MethodsNeuronal cells (primary rat cerebral cortical neurons and PC12cells) were incubated with or without Cd post-pretreatment with rapamycin (Rap) or N-acetyl-L-cysteine (NAC). Cell viability was determined by MTT assay, apoptosis was examined using flow cytometry and fluorescence microscopy, and the activation of phosphoinositide 3'-kinase/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) and mitochondrial apoptotic pathways were measured by western blotting or immunofluorescence assays. ResultsCd-induced activation of Akt/mTOR signaling, including Akt, mTOR,p70 S6 kinase (p70 S6K), and eukaryotic initiation factor 4E binding protein 1(4E-BP1). Rap, an mTOR inhibitor and NAC, a ROS scavenger, blocked Cd-induced activation of Akt/mTOR signaling and apoptosis of neuronal cells. Furthermore, NAC blocked the decrease of B-cell lymphoma 2/Bcl-2 associated X protein (Bcl-2/Bax) ratio, release of cytochrome c, cleavage of caspase-3 and poly(ADP-ribose) polymerase (PARP), and nuclear translocation of apoptosis-inducing factor(AIF)and endonuclease G (Endo G). ConclusionCd-induced ROS generation activates Akt/mTOR and mitochondrial pathways, leading to apoptosis ofneuronal cells. Our findings suggest that mTOR inhibitors or antioxidants have potential for preventing Cd-induced neurodegenerative diseases.

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

    OpenAIRE

    Wang, Y.; Zhang, Z.Z.; Y. Wu; Ke, J.J.; He, X. H.; Wang, Y L

    2013-01-01

    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], a...

  1. 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.

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

    International Nuclear Information System (INIS)

    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 GDF5Rgsc451 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

  3. Role of AKT/mTORC1 pathway in pancreatic β-cell proliferation.

    Directory of Open Access Journals (Sweden)

    Balcazar Morales, Norman

    2012-09-01

    Full Text Available Growth factors, insulin signaling and nutrients are important regulators of β-cell mass and function. The events linking these signals to regulation of β-cell mass are not completely understood. Recent findings indicate that mTOR pathway integrates signals from growth factors and nutrients with transcription, translation, cell size, cytoskeleton remodeling and mitochondrial metabolism. mTOR is a part of two distinct complexes; mTORC1 and mTORC2. The mammalian TORC1 is sensitive to rapamycin and contains Raptor, deptor, PRAS40 and the G protein β-subunit-like protein (GβL. mTORC1 activates key regulators of protein translation; ribosomal S6 kinase (S6K and eukaryote initiation factor 4E-binding protein 1.This review summarizes current findings about the role of AKT/mTORC1 signaling in regulation of pancreatic β cell mass and proliferation. mTORC1 is a major regulator of β-cell cycle progression by modulation of cyclins D2, D3 and cdk4/cyclin D activity. These studies uncovered key novel pathways controlling cell cycle progression in β-cells in vivo. This information can be used to develop alternative approaches to expand β-cell mass in vivo and in vitro without the risk of oncogenic transformation. The acquisition of such knowledge is critical for the design of improved therapeutic strategies for the treatment and cure of diabetes as well as to understand the effects of mTOR inhibitors in β-cell function.

  4. Inhibition of SH2-domain-containing inositol 5-phosphatase (SHIP2) ameliorates palmitate induced-apoptosis through regulating Akt/FOXO1 pathway and ROS production in HepG2 cells

    Energy Technology Data Exchange (ETDEWEB)

    Gorgani-Firuzjaee, Sattar [Department of Biochemistry, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Islamic Republic of Iran (Iran, Islamic Republic of); Adeli, Khosrow [Division of Clinical Biochemistry, The Hospital for Sick Children, University of Toronto, Toronto (Canada); Meshkani, Reza, E-mail: rmeshkani@tums.ac.ir [Department of Biochemistry, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Islamic Republic of Iran (Iran, Islamic Republic of)

    2015-08-21

    The serine–threonine kinase Akt regulates proliferation and survival by phosphorylating a network of protein substrates; however, the role of a negative regulator of the Akt pathway, the SH2-domain-containing inositol 5-phosphatase (SHIP2) in apoptosis of the hepatocytes, remains unknown. In the present study, we studied the molecular mechanisms linking SHIP2 expression to apoptosis using overexpression or suppression of SHIP2 gene in HepG2 cells exposed to palmitate (0.5 mM). Overexpression of the dominant negative mutant SHIP2 (SHIP2-DN) significantly reduced palmitate-induced apoptosis in HepG2 cells, as these cells had increased cell viability, decreased apoptotic cell death and reduced the activity of caspase-3, cytochrome c and poly (ADP-ribose) polymerase. Overexpression of the wild-type SHIP2 gene led to a massive apoptosis in HepG2 cells. The protection from palmitate-induced apoptosis by SHIP2 inhibition was accompanied by a decrease in the generation of reactive oxygen species (ROS). In addition, SHIP2 inhibition was accompanied by an increased Akt and FOXO-1 phosphorylation, whereas overexpression of the wild-type SHIP2 gene had the opposite effects. Taken together, these findings suggest that SHIP2 expression level is an important determinant of hepatic lipoapotosis and its inhibition can potentially be a target in treatment of hepatic lipoapoptosis in diabetic patients. - Highlights: • Lipoapoptosis is the major contributor to the development of NAFLD. • The PI3-K/Akt pathway regulates apoptosis in different cells. • The role of negative regulator of this pathway, SHIP2 in lipoapoptosis is unknown. • SHIP2 inhibition significantly reduces palmitate-induced apoptosis in HepG2 cells. • SHIP2 inhibition prevents palmitate induced-apoptosis by regulating Akt/FOXO1 pathway.

  5. The CB₁ cannabinoid receptor signals striatal neuroprotection via a PI3K/Akt/mTORC1/BDNF pathway.

    Science.gov (United States)

    Blázquez, C; Chiarlone, A; Bellocchio, L; Resel, E; Pruunsild, P; García-Rincón, D; Sendtner, M; Timmusk, T; Lutz, B; Galve-Roperh, I; Guzmán, M

    2015-10-01

    The CB1 cannabinoid receptor, the main molecular target of endocannabinoids and cannabis active components, is the most abundant G protein-coupled receptor in the mammalian brain. In particular, the CB1 receptor is highly expressed in the basal ganglia, mostly on terminals of medium-sized spiny neurons, where it plays a key neuromodulatory function. The CB1 receptor also confers neuroprotection in various experimental models of striatal damage. However, the assessment of the physiological relevance and therapeutic potential of the CB1 receptor in basal ganglia-related diseases is hampered, at least in part, by the lack of knowledge of the precise mechanism of CB1 receptor neuroprotective activity. Here, by using an array of pharmacological, genetic and pharmacogenetic (designer receptor exclusively activated by designer drug) approaches, we show that (1) CB1 receptor engagement protects striatal cells from excitotoxic death via the phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin complex 1 pathway, which, in turn, (2) induces brain-derived neurotrophic factor (BDNF) expression through the selective activation of BDNF gene promoter IV, an effect that is mediated by multiple transcription factors. To assess the possible functional impact of the CB1/BDNF axis in a neurodegenerative-disease context in vivo, we conducted experiments in the R6/2 mouse, a well-established model of Huntington's disease, in which the CB1 receptor and BDNF are known to be severely downregulated in the dorsolateral striatum. Adeno-associated viral vector-enforced re-expression of the CB1 receptor in the dorsolateral striatum of R6/2 mice allowed the re-expression of BDNF and the concerted rescue of the neuropathological deficits in these animals. Collectively, these findings unravel a molecular link between CB1 receptor activation and BDNF expression, and support the relevance of the CB1/BDNF axis in promoting striatal neuron survival. PMID:25698444

  6. Chronic modulation of AMP-Kinase, Akt and mTOR pathways by ionizing radiation in human lung cancer xenografts

    International Nuclear Information System (INIS)

    Earlier, we showed that in cancer cells, AMP-activated kinase (AMPK) participates in a signal transduction pathway involving ATM-AMPK-p53/p21cip1 which is activated by ionizing radiation (IR) to mediate G2-M arrest and enhanced cytotoxicity. We also observed that AMPK modulates ATM expression and activity and the IR response of the Akt-mTOR pathway. Since the ATM, AMPK and Akt pathways are key targets of novel radio-sensitizing therapeutics, we examined the chronic modultion of expression and activity of those pathways by IR alone in xenograft models of lung cancer. Immuno-compromised mice were grafted with human lung A549 and H1299 cells, were treated with a single fraction of 0 or 10 Gy, and left to grow for 8 weeks. Extracted tumors were subjected to lysis and immunoblotting or fixation and immunohistochemical analysis. IR inhibited significantly xenograft growth and was associated with increased expression of Ataxia Telengiectasia Mutated (ATM) and enhanced phosphorylation of two ATM targets, H2Ax and checkpoint kinase Chk2. Irradiated tumours showed increased total AMPK levels and phosphorylation of AMPK and its substrate Acetyl-CoA Carboxylase (ACC). IR led to enhanced expression and phosphorylation of p53 and cyclin dependent kinase inhibitors p21cip1 and p27kip1. However, irradiated tumours had reduced phosphorylation of Akt, mTOR and it‘s target translation initiation inhibitor 4EBP1. Irradiated xenografts showed reduced microvessel density, reduced expression of CD31 but increased expression of hypoxia-induced factor 1A (HIF1a) compared to controls. IR inhibits epithelial cancer tumour growth and results in sustained expression and activation of ATM-Chk2, and AMPK-p53/p21cip1/p27kip1 but partial inhibition of the Akt-mTOR signaling pathways. Future studies should examine causality between those events and explore whether further modulation of the AMPK and Akt-mTOR pathways by novel therapeutics can sensitize lung tumours to radiation

  7. Osthole relaxes pulmonary arteries through endothelial phosphatidylinositol 3-kinase/Akt-eNOS-NO signaling pathway in rats.

    Science.gov (United States)

    Yao, Li; Lu, Ping; Li, Yumei; Yang, Lijing; Feng, Hongxuan; Huang, Yong; Zhang, Dandan; Chen, Jianguo; Zhu, Daling

    2013-01-15

    Pulmonary arterial hypertension is a life-threatening disease lacking effective therapies. Osthole is a natural coumarin compound isolated from Angelica pubescens Maxim., which possesses hypotensive effect. Although its effects on isolated thoracic aorta (systemic circulating system) are clarified, it remains unclear whether Osthole relaxes isolated pulmonary arteries (PAs) (pulmonary circulating system). The aim of this study was to investigate the effects of Osthole on isolated PAs and the underlying mechanisms. We examined PA relaxation induced by Osthole in isolated human and rat PA rings with force-electricity transducers, the expression and activity of endothelial nitric oxide synthase (eNOS) and protein kinase B (Akt) with western blot, and nitric oxide (NO) production using DAF-FM DA fluorescent indicator. The results showed that Osthole elicited a dose-dependent vasorelaxation activity with phenylephrine-precontracted human and rat PA rings, which can be diminished by endothelium denudation and inhibition of eNOS, while having no effect on rat mesenteric arteries. Osthole increased NO release as well as activation of Akt and eNOS, indicated with increased phosphorylations of Akt at Ser-473 and eNOS at Ser-1177 in endothelial cells. PI3K inhibitor LY294002 also blocked Osthole induced vasodilation. In summary, dilative effect of Osthole was dependent on endothelial integrity and NO production, and was mediated by endothelial PI3K/Akt-eNOS-NO pathway. These may provide a new pulmonary vasodilator for the therapy of pulmonary arterial hypertension. PMID:23220709

  8. MicroRNA-150 negatively regulates the function of CD4(+) T cells through AKT3/Bim signaling pathway.

    Science.gov (United States)

    Sang, Wei; Sun, Cai; Zhang, Cong; Zhang, Dianzheng; Wang, Ying; Xu, Linyan; Zhang, Zhe; Wei, Xiangyu; Pan, Bin; Yan, Dongmei; Zhu, Feng; Yan, Zhiling; Cao, Jiang; Loughran, Thomas P; Xu, Kailin

    2016-01-01

    Donor-derived CD4(+) T lymphocytes are the major effector cells directly involved in the development of graft-versus-host disease (GVHD). As a negative regulator of immune cell differentiation and development, microRNA-150 (miR-150) induces immunological tolerance in CD4(+) T cells after transplantation. However, the specific mechanisms have not been fully elucidated. In this study, we demonstrated that miR-150 is capable of not only inhibiting proliferation and activation of CD4(+) T cells but also promoting apoptosis. Mechanistically, miR-150 targets v-akt murine thymoma viral oncogene homolog 3 (AKT3), and subsequently downregulates B-cell lymphoma 2 (Bcl-2) interacting mediator of cell death (BIM). We have also demonstrated that re-expression of AKT3 reversed miR-150-mediated inhibition of CD4(+) T lymphocyte development. Therefore, we conclude that miR-150 negatively regulates CD4(+) T cell function by inhibiting the AKT3/BIM signaling pathway. These findings also suggest that manipulating the levels of miRNA-150 could be a valuable strategy in prevention and/or treatment of acute graft-versus-host disease. PMID:27329362

  9. Depression of p53-independent Akt survival signals in human oral cancer cells bearing mutated p53 gene after exposure to high-LET radiation

    International Nuclear Information System (INIS)

    Highlights: ► High-LET radiation induces efficiently apoptosis regardless of p53 gene status. ► We examined whether high-LET radiation depresses the Akt-survival signals. ► High-LET radiation depresses of survival signals even in the mp53 cancer cells. ► High-LET radiation activates Caspase-9 through depression of survival signals. ► High-LET radiation suppresses cell growth through depression of survival signals. -- Abstract: Although mutations and deletions in the p53 tumor suppressor gene lead to resistance to low linear energy transfer (LET) radiation, high-LET radiation efficiently induces cell lethality and apoptosis regardless of the p53 gene status in cancer cells. Recently, it has been suggested that the induction of p53-independent apoptosis takes place through the activation of Caspase-9 which results in the cleavage of Caspase-3 and poly (ADP-ribose) polymerase (PARP). This study was designed to examine if high-LET radiation depresses serine/threonine protein kinase B (PKB, also known as Akt) and Akt-related proteins. Human gingival cancer cells (Ca9–22 cells) harboring a mutated p53 (mp53) gene were irradiated with 2 Gy of X-rays or Fe-ion beams. The cellular contents of Akt-related proteins participating in cell survival signaling were analyzed with Western Blotting 1, 2, 3 and 6 h after irradiation. Cell cycle distributions after irradiation were assayed with flow cytometric analysis. Akt-related protein levels decreased when cells were irradiated with high-LET radiation. High-LET radiation increased G2/M phase arrests and suppressed the progression of the cell cycle much more efficiently when compared to low-LET radiation. These results suggest that high-LET radiation enhances apoptosis through the activation of Caspase-3 and Caspase-9, and suppresses cell growth by suppressing Akt-related signaling, even in mp53 bearing cancer cells.

  10. Antiproliferative effect of growth hormone-releasing hormone (GHRH antagonist on ovarian cancer cells through the EGFR-Akt pathway

    Directory of Open Access Journals (Sweden)

    Varga Jozsef

    2010-05-01

    Full Text Available Abstract Background Antagonists of growth hormone-releasing hormone (GHRH are being developed for the treatment of various human cancers. Methods MTT assay was used to test the proliferation of SKOV3 and CaOV3. The splice variant expression of GHRH receptors was examined by RT-PCR. The expression of protein in signal pathway was examined by Western blotting. siRNA was used to block the effect of EGFR. Results In this study, we investigated the effects of a new GHRH antagonist JMR-132, in ovarian cancer cell lines SKOV3 and CaOV3 expressing splice variant (SV1 of GHRH receptors. MTT assay showed that JMR-132 had strong antiproliferative effects on SKOV3 and CaOV3 cells in both a time-dependent and dose-dependent fashion. JMR-132 also induced the activation and increased cleaved caspase3 in a time- and dose-dependent manner in both cell lines. In addition, JMR-132 treatments decreased significantly the epidermal growth factor receptor (EGFR level and the phosphorylation of Akt (p-Akt, suggesting that JMR-132 inhibits the EGFR-Akt pathway in ovarian cancer cells. More importantly, treatment of SKOV3 and CaOV3 cells with 100 nM JMR-132 attenuated proliferation and the antiapoptotic effect induced by EGF in both cell lines. After the knockdown of the expression of EGFR by siRNA, the antiproliferative effect of JMR-132 was abolished in SKOV3 and CaOV3 cells. Conclusions The present study demonstrates that the inhibitory effect of the GHRH antagonist JMR-132 on proliferation is due, in part, to an interference with the EGFR-Akt pathway in ovarian cancer cells.

  11. Maternal Disononyl Phthalate Exposure Activates Allergic Airway Inflammation via Stimulatingthe Phosphoinositide 3-kinase/Akt Pathway in Rat Pups

    Institute of Scientific and Technical Information of China (English)

    CHEN Li; CHEN Jiao; XIE ChangMing; ZHAO Yan; WANG Xiu; andZHANG YunHui

    2015-01-01

    ObjectiveTo evaluate the effectof diisononyl phthalate (DINP) exposure during gestation and lacta-tion on allergic response in pups and to explore the role of phosphoinositide 3-kinase/Akt pathway on it. MethodsFemale Wistar rats were treated with DINP at different dosages (0, 5, 50,and 500 mg/kg of body weight per day). The pups were sensitized and challenged by ovalbumin (OVA). The airway response was assessed; the airway histological studies were performed by hematoxylin and eosin (HE) staining; and the relative cytokines in phosphoinositide 3-kinase (PI3K)/Akt pathway were measured by enzyme-linked immunosorbent assay (ELISA) and western blot analysis. ResultsThere was no significant difference in DINP’s effect on airway hyperresponsiveness (AHR) between male pups and female pups. In the 50 mg/(kg·d) DINP-treated group, airway response to OVA significantly increased and pups showed dramatically enhanced pulmonary resistance (RI) compared with those from controls (P<0.05). Enhanced Akt phosphorylation and NF-κB translocation, and Th2 cytokines expression were observed in pups of 50 mg/(kg·d) DINP-treated group. However, in the 5 and 500 mg/(kg·d) DINP-treated pups, no significant effects were observed. ConclusionTherewas an adjuvant effect of DINP on allergic airway inflammation in pups. Maternal DINP exposure could promote OVA-induced allergic airway response in pups in part by upregulation of PI3K/Akt pathway.

  12. Role of SIRT1-mediated mitochondrial and Akt pathways in glioblastoma cell death induced by Cotinus coggygria flavonoid nanoliposomes

    Directory of Open Access Journals (Sweden)

    Wang G

    2015-08-01

    Full Text Available Gang Wang,1,2,* Jun Jie Wang,1,2,* Tony SS To,3 Hua Fu Zhao,3 Jing Wang3 1Department of Pharmaceutics, Shanghai Eighth People’s Hospital, Shanghai, People’s Republic of China; 2College of Pharmacy, Hubei University of Medicine, Shiyan, Hubei Province, People’s Republic of China; 3Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong SAR, People’s Republic of China *These authors contributed equally to this work Abstract: Flavonoids, the major polyphenol components in Cotinus coggygria (CC, have been found to show an anticancer effect in our previous study; however, the exact mechanisms of inducing human glioblastoma (GBM cell death remain to be resolved. In this study, a novel polyvinylpyrrolidone K-30/sodium dodecyl sulfate and polyethyleneglycol-coated liposome loaded with CC flavonoids (CCFs was developed to enhance solubility and the antibrain tumor effect, and the molecular mechanism regarding how CCF nanoliposomes (CCF-NLs induce apoptotic cell death in vitro was investigated. DBTRG-05MG GBM cell lines treated with CCF-NLs showed potential antiproliferative effects. Regarding the underlying mechanisms of inducing apoptosis in DBTRG-05MG GBM cells, CCF-NLs were shown to downregulate the expression of antiapoptotic B-cell lymphoma/leukemia 2 (Bcl-2, an apoptosis-related protein family member, but the expression of proapoptotic Bcl-2-associated X protein was enhanced compared with that in controls. CCF-NLs also inhibited the activity of caspase-3 and -9, which is the initiator caspase of the extrinsic and intrinsic apoptotic pathways. Blockade of caspase activation consistently induced apoptosis and inhibited growth in CCF-NL-treated DBTRG-05MG cells. This study further investigated the role of the Akt pathway in the apoptotic cell death by CCF-NLs, showing that CCF-NLs deactivated Akt. Specifically, CCF-NLs downregulated the expression of p-Akt and SIRT1 as well as the level of

  13. Sporoderm-Broken Spores of Ganoderma lucidum Inhibit the Growth of Lung Cancer: Involvement of the Akt/mTOR Signaling Pathway.

    Science.gov (United States)

    Chen, Yali; Lv, Jing; Li, Kun; Xu, Jing; Li, Mingyan; Zhang, Wen; Pang, Xiufeng

    2016-10-01

    The sporoderm-broken spores of Ganoderma lucidum (SBGS) and their extracts exhibited a wide range of biological activities. In the present study, we prepare ethanol/ethanol extract (E/E-SBGS) and ethanol/aqueous extract (E/A-SBGS) from SBGS and examine their antitumor activities against human lung cancer. Our results showed that E/E-SBGS, not E/A-SBGS, inhibited the survival and migration of lung cancer cells in a dose-dependent manner. E/E-SBGS arrested cell cycle at G2/M phase and triggered apoptosis by decreasing the expression and activity of cell cycle regulators, cyclin B1 and cdc2, as well as anti-apoptotic proteins, Bcl-2 and Bcl-xl. Consequently, colony formation of lung cancer cells was markedly blocked by E/E-SBGS at subtoxic concentrations. Oral administration of both E/E-SBGS and SBGS significantly suppressed tumor volume and tumor weight without gross toxicity in mice. Mechanism study showed that E/E-SBGS dose-dependently suppressed the activation of Akt, the mammalian target of rapamycin (mTOR) and their downstream molecules S6 kinase and 4E-BP1 in treated tumor cells. Taken together, these results indicate that the ethanol extract of sporoderm-broken spores of G. lucidum suppresses the growth of human lung cancer, at least in part, through inhibition of the Akt/mTOR signaling pathway, suggesting its potential role in cancer treatments.

  14. Krüppel-like factor 14 increases insulin sensitivity through activation of PI3K/Akt signal pathway.

    Science.gov (United States)

    Yang, Min; Ren, Yan; Lin, Zhimin; Tang, Chenchen; Jia, Yanjun; Lai, Yerui; Zhou, Tingting; Wu, Shaobo; Liu, Hua; Yang, Gangyi; Li, Ling

    2015-11-01

    Genome-wide association studies (GWAS) have shown that Krüppel-like factor 14 (KLF14) is associated with type 2 diabetes mellitus (T2DM). However, no report has demonstrated a relationship between KLF14 and glucose metabolism. The aim of this study was to determine whether KLF14 is associated with glucose metabolism and insulin signaling in vitro. The mRNA and protein expressions of KLF14 were determined by Real-time PCR and Western blotting. Glucose uptake was assessed by 2-[(3)H]-deoxyglucose (2-DG) uptake. Western blotting was used to identify the activation of insulin signaling proteins. KLF14 mRNA and protein in fat and muscle were significantly decreased in HFD-fed mice, db/db mice and T2DM patients. Overexpression of KLF14 enhanced insulin-stimulated glucose uptake and the activation of Akt kinase in Hepa1-6 cells. The phosphorylation of insulin receptor (InsR), insulin receptor substrate-1(IRS-1), glycogen synthase kinase-3β (GSK-3β) and Akt also elevated significantly by up-regulation of KLF14. KLF14 overexpression in Hepa1-6 cells prevented the inhibition of glucose uptake and Akt phosphorylation induced by high glucose and/or high insulin, or T2DM serum. However, KLF14's ability to increase glucose uptake and Akt activation was significantly attenuated by LY294002, a PI3-kinase inhibitor. These data suggested that KLF14 could increase insulin sensitivity probably through the PI3K/Akt pathway. PMID:26226221

  15. Cadmium Activates Multiple Signaling Pathways That Coordinately Stimulate Akt Activity to Enhance c-Myc mRNA Stability.

    Directory of Open Access Journals (Sweden)

    Jia-Shiuan Tsai

    Full Text Available Cadmium is a known environmental carcinogen. Exposure of Cd leads to the activation of several proto-oncogenes in cells. We investigated here the mechanism of c-Myc expression in hepatic cells under Cd treatment. The c-Myc protein and mRNA levels increased in dose- and time-dependent manners in HepG2 cells with Cd treatment. This increase was due to an increase in c-Myc mRNA stability. To explore the mechanism involved in enhancing the mRNA stability, several cellular signaling factors that evoked by Cd treatment were analyzed. PI3K, p38, ERK and JNK were activated by Cd. However, ERK did not participate in the Cd-induced c-Myc expression. Further analysis revealed that mTORC2 was a downstream factor of p38. PI3K, JNK and mTORC2 coordinately activated Akt. Akt was phosphorylated at Thr450 in the untreated cells. Cd treatment led to additional phosphorylation at Thr308 and Ser473. Blocking any of the three signaling factors resulted in the reduction of phosphorylation level at all three Akt sites. The activated Akt phosphorylated Foxo1 and allowed the modified protein to translocate into the cytoplasm. We conclude that Cd-induced accumulation of c-Myc requires the activation of several signaling pathways. The signals act coordinately for Akt activation and drive the Foxo1 from the nucleus to the cytoplasm. Reduction of Foxo1 in the nucleus reduces the transcription of its target genes that may affect c-Myc mRNA stability, resulting in a higher accumulation of the c-Myc proteins.

  16. PDGF stimulation of Mueller cell proliferation: Contributions of c-JNK and the PI3K/Akt pathway

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Sang Woong [Department of Ophthalmology, Seoul Paik Hospital, Inje University College of Medicine, Busan (Korea, Republic of); Chung, Eun Jee [Department of Ophthalmology, National Health Insurance Corporation, Ilsan Hospital, Gyounggi-do (Korea, Republic of); Jung, Sun-Ah [Myunggok Eye Research Institute, Kim' s Eye Hospital, Konyang University College of Medicine, Seoul (Korea, Republic of); Lee, Joon H., E-mail: joonhlee@konyang.ac.kr [Myunggok Eye Research Institute, Kim' s Eye Hospital, Konyang University College of Medicine, Seoul (Korea, Republic of)

    2009-10-09

    Platelet-derived growth factor (PDGF) has a critical role in proliferative vitreoretinopathy (PVR) as a chemoattractant and mitogen for retinal pigment epithelial cells and retinal glial cells. Here, we investigated the potential effects of PDGF on the proliferation of Mueller cells and the intracellular signaling pathway mediating these changes. PDGF induced Mueller cell proliferation and increased phosphorylation of the PDGF receptor (PDGFR), as shown by an MTT assay and immunoprecipitation analyses. Both effects were blocked by JNJ, a PDGFR-selective tyrosine kinase inhibitor. PDGF also stimulated phosphorylation of c-JNK and Akt. PDGF-induced Mueller cell proliferation was significantly reduced by pre-treatment with SP600125 and LY294002, inhibitors of c-JNK and Akt phosphorylation, respectively. Our findings collectively indicate that PDGF-stimulated Mueller cell proliferation occurs via activation of the c-JNK and PI3K/Akt signaling pathways. These data provide useful information in establishing the role of Mueller cells in the development of proliferative vitreoretinopathy.

  17. C-reactive protein inhibits survivin expression via Akt/mTOR pathway downregulation by PTEN expression in cardiac myocytes.

    Directory of Open Access Journals (Sweden)

    Beom Seob Lee

    Full Text Available C-reactive protein (CRP is one of the most important biomarkers for arteriosclerosis and cardiovascular disease. Recent studies have shown that CRP affects cell cycle and inflammatory process in cardiac myocytes. Survivin is also involved in cardiac myocytes replication and apoptosis. Reduction of survivin expression is associated with less favorable cardiac remodeling in animal models. However, the effect of CRP on survivin expression and its cellular mechanism has not yet been studied. We demonstrated that treatment of CRP resulted in a significant decrease of survivin protein expression in a concentration-dependent manner in cardiac myocytes. The upstream signaling proteins of survivin, such as Akt, mTOR and p70S6K, were also downregulated by CRP treatment. In addition, CRP increased the protein and mRNA levels of PTEN. The siRNA transfection or specific inhibitor treatment for PTEN restored the CRP-induced downregulation of Akt/mTOR/p70S6K pathway and survivin protein expression. Moreover, pretreatment with a specific p53 inhibitor decreased the CRP-induced PTEN expression. ERK-specific inhibitor also blocked the p53 phosphorylation and PTEN expression induced by CRP. Our study provides a novel insight into CRP-induced downregulation of survivin protein expression in cardiac myocytes through mechanisms that involved in downregulation of Akt/mTOR/p70S6K pathway by expression of PTEN.

  18. Novel alkylphospholipid-DTC hybrids as promising agents against endocrine related cancers acting via modulation of Akt-pathway.

    Science.gov (United States)

    Jangir, Santosh; Bala, Veenu; Lal, Nand; Kumar, Lalit; Sarswat, Amit; Kumar, Amit; Hamidullah; Saini, Karan S; Sharma, Vikas; Verma, Vikas; Maikhuri, Jagdamba P; Konwar, Rituraj; Gupta, Gopal; Sharma, Vishnu L

    2014-10-01

    A new series of 2-(alkoxy(hydroxy)phosphoryloxy)ethyl dialkylcarbodithioate derivatives was synthesized and evaluated against endocrine related cancers, acting via modulation of Akt-pathway. Eighteen compounds were active at 7.24-100 μM against MDA-MB-231 or MCF-7 cell lines of breast cancer. Three compounds (14, 18 and 22) were active against MCF-7 cells at IC50 significantly better than miltefosine and most of the compounds were less toxic towards non-cancer cell lines, HEK-293. On the other hand, twelve compounds exhibited cell growth inhibiting activity against prostate cancer cell lines, either PC-3 or DU-145 at 14.69-95.20 μM. While nine of these were active against both cell lines. The most promising compounds 14 and 18 were about two and five fold more active than miltefosine against DU-145 and MCF-7 cell lines respectively and significantly down regulated phospho-Akt. Possibly anti-cancer and pro-apoptotic activity was mostly due to blockade of Akt-pathway.

  19. 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.

  20. Xenon-delayed postconditioning attenuates spinal cord ischemia/reperfusion injury through activation AKT and ERK signaling pathways in rats.

    Science.gov (United States)

    Liu, Shiyao; Yang, Yanwei; Jin, Mu; Hou, Siyu; Dong, Xiuhua; Lu, Jiakai; Cheng, Weiping

    2016-09-15

    Previous studies have shown that xenon-delayed postconditioning for up to 2h after reperfusion provides protection against spinal cord ischemia/reperfusion (I/R) injury in rats. This study was designed to determine the roles of phosphatidylinositol 3-kinase (PI3K)-Akt and extracellular signal-regulated kinase (ERK) in this neuroprotection. The rats were randomly assigned to the following nine groups (n=16∗9): 1) I/R+N2 group, 2) I/R+Xe group, 3) I/R+PD98059+N2 group (ERK blocking agent), 4) I/R+wortmannin+N2 group (PI3K-Akt blocking agent), 5) I/R+PD98059+Xe group, 6) I/R+wortmannin+Xe group, 7) I/R+DMSO+Xe group (dimethyl sulfoxide, vehicle control), 8) I/R+DMSO+N2 group, and 9) sham group (no spinal cord ischemia and no xenon). Spinal cord ischemia was induced for 25min in male Sprague-Dawley rats. Neurological function was assessed using the Basso, Beattie, and Bresnahan (BBB) open-field locomotor scale at 6, 12, 24 and 48h after reperfusion. Histological examination of the lumbar spinal cord was performed using Nissl staining and TUNEL staining at 4 (n=8) and 48 (n=8)h after reperfusion. Western blotting was performed to evaluate p-Akt and p-ERK expression in the spinal cord at 4 (n=8) and 48 (n=8) h after reperfusion. Compared with the sham group, all rats in the I/R groups had lower BBB scores, fewer normal motor neurons, more apoptotic neurons and lower p-Akt and p-ERK levels at each time point (P<0.05). Compared with the I/R group, rats in the I/R+Xe group had higher neurological scores, more normal motor neurons, fewer apoptotic neurons and significantly higher levels of p-Akt and p-ERK at each time point (P<0.05). Compared with the I/R+Xe group, the I/R+PD98059+Xe and I/R+wortmannin+Xe groups showed worse neurological outcomes and less p-Akt and p-ERK at each time point (P<0.05). These results suggest that xenon-delayed postconditioning improves neurological outcomes to spinal cord I/R injury in rats through the activation of the AKT and ERK signaling

  1. Combinatorial anticancer effects of curcumin and sorafenib towards thyroid cancer cells via PI3K/Akt and ERK pathways.

    Science.gov (United States)

    Zhang, Junjia; Yu, Jichun; Xie, Rong; Chen, Wanzhi; Lv, Yunxia

    2016-08-01

    The objective of this study was to examine the in vitro combinatorial anticancer effects of curcumin and sorafenib towards thyroid cancer cells FTC133 using a MTT cytotoxicity assay, and to test whether the mechanism involves induction of apoptosis. The present results demonstrated that curcumin at 15-25 μM dose-dependently suppressed the proliferation of FTC133. Combined treatment (curcumin (25 μM) and sorafenib (2 μM)) resulted in a reduction in cell colony formation and significantly decreased the invasion and migration of FTC133 cells compared with that treated with individual drugs. Western blot showed that the levels of p-ERK and p-Akt proteins were significantly reduced (p curcumin was found to dose-dependently inhibit the apoptosis of FTC133 cells possibly via PI3K/Akt and ERK pathways. There is a synergetic antitumour effect between curcumin and sorafenib. PMID:26299635

  2. 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.

  3. Vorinostat Enhances Cytotoxicity of SN-38 and Temozolomide in Ewing Sarcoma Cells and Activates STAT3/AKT/MAPK Pathways.

    Directory of Open Access Journals (Sweden)

    Valerie B Sampson

    Full Text Available Histone deacetylase inhibitors (HDACi have been evaluated in patients with Ewing sarcoma (EWS but demonstrated limited activity. To better understand the potential for HDACi in EWS, we evaluated the combination of the HDACi vorinostat, with DNA damaging agents SN-38 (the active metabolite of irinotecan and topoisomerase 1 inhibitor plus the alkylating agent temozolomide (ST. Drugs were evaluated in sequential and simultaneous combinations in two EWS cell lines. Results demonstrate that cell viability, DNA damage and reactive oxygen species (ROS production are dependent on the sequence of drug administration. Enhanced cytotoxicity is exhibited in vitro in EWS cell lines treated with ST administered before vorinostat, which was modestly higher than concomitant treatment and superior to vorinostat administered before ST. Drug combinations downregulate cyclin D1 to induce G0/G1 arrest and promote apoptosis by cleavage of caspase-3 and PARP. When ST is administered before or concomitantly with vorinostat there is activation of STAT3, MAPK and the p53 pathway. In contrast, when vorinostat is administered before ST, there is DNA repair, increased AKT phosphorylation and reduced H2B acetylation. Inhibition of AKT using the small molecule inhibitor MK-2206 did not restore H2B acetylation. Combining ST with the dual ALK and IGF-1R inhibitor, AZD3463 simultaneously inhibited STAT3 and AKT to enhance the cytotoxic effects of ST and further reduce cell growth suggesting that STAT3 and AKT activation were in part mediated by ALK and IGF-1R signaling. In summary, potent antiproliferative and proapoptotic activity were demonstrated for ST induced DNA damage before or simultaneous with HDAC inhibition and cell death was mediated through the p53 pathway. These observations may aid in designing new protocols for treating pediatric patients with high-risk EWS.

  4. WISP1 overexpression promotes proliferation and migration of human vascular smooth muscle cells via AKT signaling pathway.

    Science.gov (United States)

    Lu, Shun; Liu, Hao; Lu, Lihe; Wan, Heng; Lin, Zhiqi; Qian, Kai; Yao, Xingxing; Chen, Qing; Liu, Wenjun; Yan, Jianyun; Liu, Zhengjun

    2016-10-01

    Proliferation and migration of vascular smooth muscle cells (VSMCs) play crucial roles in the development of vascular restenosis. Our previous study showed that CCN4, namely Wnt1 inducible signaling pathway protein 1 (WISP1), significantly promotes proliferation and migration of rat VSMCs, but its mechanism remains unclear. This study aims to investigate whether and how WISP1 stimulates proliferation and migration of human VSMCs. Western blot analysis showed that FBS treatment increased WISP1 protein levels in human VSMCs in a dose-dependent manner. Overexpression of WISP1 using adenovirus encoding WISP1 (AD-WISP1) significantly increased proliferation rate of human VSMCs by 2.98-fold compared with empty virus (EV)-transfected cells, shown by EdU incorporation assay. Additionally, Scratch-induced wound healing assay revealed that adenovirus-mediated overexpression of WISP1 significantly increased cell migration compared with EV-transfected cells from 6h (4.56±1.14% vs. 11.23±2.25%, PMigration Assay confirmed that WISP1 overexpression significantly promoted human VSMC migration by 2.25-fold compared with EV. Furthermore, WISP1 overexpression stimulated Akt signaling activation in human VSMCs. Blockage of Akt signaling by Akt inhibitor AZD5363 or PI3K inhibitor LY294002, led to an inhibitory effect of WISP1-induced proliferation and migration in human VSMCs. Moreover, we found that WISP1 overexpression stimulated GSK3α/β phosphorylation, and increased expression of cyclin D1 and MMP9 in human VSMCs, and this effect was abolished by AZD5363. Collectively, we demonstrated that Akt signaling pathway mediates WISP1-induced migration and proliferation of human VSMCs, suggesting that WISP1 may act as a novel potential therapeutic target for vascular restenosis.

  5. Adipose stromal cells amplify angiogenic signaling via the VEGF/mTOR/Akt pathway in a murine hindlimb ischemia model: a 3D multimodality imaging study.

    Directory of Open Access Journals (Sweden)

    Weiwei Fan

    Full Text Available Although adipose-derived stromal cell (ADSC transplantation has been demonstrated as a promising therapeutic strategy for peripheral arterial disease (PAD, the mechanism of action behind the observed therapeutic efficacy of ADSCs remains unclear. This study was designed to investigate the long-term outcome and therapeutic behavior of engrafted ADSCs in a murine hindlimb ischemia model using multimodality molecular imaging approaches. ADSCs (1.0×10(7 were isolated from Tg(Fluc-egfp mice which constitutively express dual-reporter firefly luciferase and enhanced green fluorescent protein (Fluc(+-eGFP(+, mADSCs(Fluc+GFP+, then intramuscularly injected into the hindlimb of BALB/c-nu mice after unilateral femoral artery ligation and excision. Abbreviated survival (∼5 weeks of post-transplant mADSCs within the ischemic hindlimb was longitudinally monitored using noninvasive bioluminescence imaging (BLI, fluorescence imaging (FRI, and bioluminescence tomography with micro-computed tomography (BLT/micro-CT. Use of the BLT/micro-CT system enabled quantitative 3-dimensional (3D imaging of the cells' distribution and kinetics in vivo. Engrafted mADSCs improved blood perfusion recovery, ambulatory performance and prognosis of the ischemic hindlimb, probably by inducing angiogenesis and formation of collateral vessels, which could be visualized using laser Doppler perfusion imaging (LDPI, micro-CT angiography, vascular-cast imaging, and immunofluorescence. mADSCs augmented activation of the pro-angiogenic VEGF/mTOR/Akt pathway in vivo, even though the cells failed to incorporate into the host microvasculature as functional components. Downregulation of VEGF/mTOR/Akt signaling using small molecule inhibitors counteracted mADSC-induced angiogenesis and perfusion restoration. This study demonstrates for the first time the spatiotemporal kinetics and functional survival of transplanted mADSCs in a PAD model using in vivo 3D multimodality imaging. Our study

  6. Dioscin inhibits colon tumor growth and tumor angiogenesis through regulating VEGFR2 and AKT/MAPK signaling pathways

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Qingyi [Regenerative Medicine Research Center, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan 610041 (China); Qing, Yong, E-mail: qingyongxy@yahoo.co.jp [Department of Pharmacology, West China School of Pharmacy, Sichuan University, Chengdu, Sichuan 610041 (China); Wu, Yang [State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan 610041 (China); Hu, Xiaojuan; Jiang, Lei [Department of Pharmacology, West China School of Pharmacy, Sichuan University, Chengdu, Sichuan 610041 (China); Wu, Xiaohua, E-mail: wuxh@scu.edu.cn [Regenerative Medicine Research Center, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan 610041 (China)

    2014-12-01

    Dioscin has shown cytotoxicity against cancer cells, but its in vivo effects and the mechanisms have not elucidated yet. The purpose of the current study was to assess the antitumor effects and the molecular mechanisms of dioscin. We showed that dioscin could inhibit tumor growth in vivo and has no toxicity at the test condition. The growth suppression was accompanied by obvious blood vessel decrease within solid tumors. We also found dioscin treatment inhibited the proliferation of cancer and endothelial cell lines, and most sensitive to primary cultured human umbilical vein endothelial cells (HUVECs). What's more, analysis of HUVECs migration, invasion, and tube formation exhibited that dioscin has significantly inhibitive effects to these actions. Further analysis of blood vessel formation in the matrigel plugs indicated that dioscin could inhibit VEGF-induced blood vessel formation in vivo. We also identified that dioscin could suppress the downstream protein kinases of VEGFR2, including Src, FAK, AKT and Erk1/2, accompanied by the increase of phosphorylated P38MAPK. The results potently suggest that dioscin may be a potential anticancer drug, which efficiently inhibits angiogenesis induced by VEGFR2 signaling pathway as well as AKT/MAPK pathways. - Highlights: • Dioscin inhibits tumor growth in vivo and does not exhibit any toxicity. • Dioscin inhibits angiogenesis within solid tumors. • Dioscin inhibits the proliferation, migration, invasion, and tube formation of HUVECs. • Dioscin inhibits VEGF–induced blood vessel formation in vivo. • Dioscin inhibits VEGFR2 signaling pathway as well as AKT/MAPK pathway.

  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. PMID:23417763

  8. 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. PMID:27398138

  9. Research development of AKT/PKB pathway in non-small cell lung cancer%AKT/PKB通路在非小细胞肺癌中作用的研究进展

    Institute of Scientific and Technical Information of China (English)

    蒲蓉; 李为民

    2009-01-01

    AKT/~白激酶B(protein kinase B,PKB)是一种丝氨酸/苏氨酸蛋白激酶,传递生长因子等胞外刺激信号,参与调节细胞凋亡、增生、分化和代谢等一系列生理活动.目前在肿瘤的研究中发现AKT/PKB的激活与肿瘤的发生、发展以及肿瘤血管的形成都有密切的关系.本文就AKT/PKB通路在非小细胞肺癌中作用的研究进展进行综述.%AKT/protein kinase B(PKB)is a kind of serine/thyring kinases.It plays a role in the transportation of extracellular stimuli signal,such as growth factor,and participates in a series of physiological activities,such as cell apoptosis,proliferation,differation and metabolism.At present,manyresearches show AKT/PKB has close relationship with tumor genesis,development and angiogenesis.The article reviews the role of AKT/PKB pathway in non-small cell lung cancer.

  10. Transmembrane-Bound IL-15-Promoted Epithelial-Mesenchymal Transition in Renal Cancer Cells Requires the Src-Dependent Akt/GSK-3β/β-Catenin Pathway.

    Science.gov (United States)

    Yuan, Huaqin; Meng, Xiaoxin; Guo, Wenjie; Cai, Peifen; Li, Wanshuai; Li, Qian; Wang, Weicheng; Sun, Yang; Xu, Qiang; Gu, Yanhong

    2015-05-01

    Intrarenal interleukin-15 (IL-15) plays a major role controlling epithelial survival and polarization both in physiological and pathologic conditions. Herein, we confirmed that human renal cell carcinomas (RCCs) express a membrane-bound IL-15 isoform displaying an unusual molecular weight of 27 kDa. Its stimulation with soluble IL-15 receptor α chain (s-IL-15Rα) triggers epithelial-mesenchymal transition (EMT) process as shown by the down-regulation of E-cadherin and zona occludens 1 and the up-regulation of vimentin and N-cadherin and promotes the migratory and invasive properties of RCC. S-IL-15Rα treatment triggered the Src/PI3K/Akt/GSK-3β pathway and promoted β-catenin nuclei translocation. Deactivation of this pathway by using Src-specific inhibitor PP2, PI3K inhibitor LY294002, and AKT inhibitor MK2206 hampered β-catenin nuclei translocation and suppressed EMT, migration, and invasion of RCC. S-IL-15Rα treatment also enhanced Src-dependent phosphorylation of focal adhesion kinase (FAK) and extracellular signal-regulated kinase (Erk1/2). FAK knockdown significantly decreased the migration and invasion of RCC, which suggest that Src-FAK signaling was involved in s-IL-15Rα-favored migration and invasion of RCC. At the same time, inhibitors of Erk1/2 also significantly decreased the migration and invasion of RCC but could not reverse s-IL-15Rα-induced EMT. Taken together, our results reveal that Src-dependent PI3K/Akt/GSK3b/β-catenin pathway is required for s-IL-15Ra-dependent induction of EMT in RCC, while Src-FAK and Src-Erk1/2 signaling were involved in s-IL-15Rα-promoted migration and invasion properties of RCC. Our study provides a better understanding of IL-15 signaling in RCC tumor progression, which may lead to novel targeted therapies and provide some suggestions when using IL-15 in clinic. PMID:26025664

  11. Hydrogen Sulfide Prevents Synaptic Plasticity from VD-Induced Damage via Akt/GSK-3β Pathway and Notch Signaling Pathway in Rats.

    Science.gov (United States)

    Liu, Chunhua; Xu, Xiaxia; Gao, Jing; Zhang, Tao; Yang, Zhuo

    2016-08-01

    Our previous study has demonstrated that hydrogen sulfide (H2S) attenuates neuronal injury induced by vascular dementia (VD) in rats, but the mechanism is still poorly understood. In this study, we aimed to investigate whether the neuroprotection of H2S was associated with synaptic plasticity and try to interpret the potential underlying mechanisms. Adult male Wistar rats were suffered the ligation of bilateral common carotid arteries. At 24 h after surgery, rats were administered intraperitoneally with sodium hydrosulfide (NaHS, 5.6 mg·kg(-1)·day(-1)), a H2S donor, for 3 weeks in the VD+NaHS group and treated intraperitoneally with saline in the VD group respectively. Our results demonstrated that NaHS significantly decreased the level of glutamate. It obviously ameliorated cognitive flexibility as well as the spatial learning and memory abilities by Morris water maze. Moreover, NaHS significantly improved the long-term depression (LTD), and was able to elevate the expression of N-methyl-D-aspartate receptor subunit 2A, which plays a pivotal role in synaptic plasticity. Interestingly, NaHS decreased the phosphorylation of Akt, and it could maintain the activity of glycogen synthase kinase-3β (GSK-3β). Surprisingly, NaHS triggered the canonical Notch pathway by increasing expressions of Jagged-1 and Hes-1. These findings suggest that NaHS prevents synaptic plasticity from VD-induced damage partly via Akt/GSK-3β pathway and Notch signaling pathway.Hydrogen sulfide modulated the ratio of NMDAR 2A/2B and improved the synaptic plasticity via Akt/GSK-3β pathway and Notch signaling pathway in VD rats.

  12. PI3K/Akt/mTOR pathway inhibitors enhance radiosensitivity in radioresistant prostate cancer cells through inducing apoptosis, reducing autophagy, suppressing NHEJ and HR repair pathways.

    Science.gov (United States)

    Chang, L; Graham, P H; Hao, J; Ni, J; Bucci, J; Cozzi, P J; Kearsley, J H; Li, Y

    2014-01-01

    The PI3K/Akt/mTOR pathway has a central role in cancer metastasis and radiotherapy. To develop effective therapeutics to improve radiosensitivity, understanding the possible pathways of radioresistance involved and the effects of a combination of the PI3K/Akt/mTOR inhibitors with radiotherapy on prostate cancer (CaP) radioresistant cells is needed. We found that compared with parent CaP cells, CaP-radioresistant cells demonstrated G0/G1 and S phase arrest, activation of cell cycle check point, autophagy and DNA repair pathway proteins, and inactivation of apoptotic proteins. We also demonstrated that compared with combination of single PI3K or mTOR inhibitors (BKM120 or Rapamycin) and radiation, low-dose of dual PI3K/mTOR inhibitors (BEZ235 or PI103) combined with radiation greatly improved treatment efficacy by repressing colony formation, inducing more apoptosis, leading to the arrest of the G2/M phase, increased double-strand break levels and less inactivation of cell cycle check point, autophagy and non-homologous end joining (NHEJ)/homologous recombination (HR) repair pathway proteins in CaP-radioresistant cells. This study describes the possible pathways associated with CaP radioresistance and demonstrates the putative mechanisms of the radiosensitization effect in CaP-resistant cells in the combination treatment. The findings from this study suggest that the combination of dual PI3K/Akt/mTOR inhibitors (BEZ235 or PI103) with radiotherapy is a promising modality for the treatment of CaP to overcome radioresistance. PMID:25275598

  13. GLP1 protects cardiomyocytes from palmitate-induced apoptosis via Akt/GSK3b/b-catenin pathway.

    Science.gov (United States)

    Ying, Ying; Zhu, Huazhang; Liang, Zhen; Ma, Xiaosong; Li, Shiwei

    2015-12-01

    Activation of apoptosis in cardiomyocytes by saturated palmitic acids contributes to cardiac dysfunction in diabetic cardiomyopathy. Beta-catenin (b-catenin) is a transcriptional regulator of several genes involved in survival/anti-apoptosis. However, its role in palmitate-induced cardiomyocyte apoptosis remains unclear. Glucagon-like peptide 1 (GLP1) has been shown to exhibit potential cardioprotective properties. This study was designed to evaluate the role of b-catenin signalling in palmitate-induced cardiomyocyte apoptosis and the molecular mechanism underlying the protective effects of GLP1 on palmitate-stressed cardiomyocytes. Exposure of neonatal rat cardiomyocytes to palmitate increased the fatty acid transporter CD36-mediated intracellular lipid accumulation and cardiomyocyte apoptosis, decreased accumulation and nuclear translocation of active b-catenin, and reduced expression of b-catenin target protein survivin and BCL2. These detrimental effects of palmitate were significantly attenuated by GLP1 co-treatment. However, the anti-apoptotic effects of GLP1 were markedly abolished when b-catenin was silenced with a specific short hairpin RNA. Furthermore, analysis of the upstream molecules and mechanisms responsible for GLP1-associated cardiac protection revealed that GLP1 restored the decreased phosphorylation of protein kinase B (Akt) and glycogen synthase kinase-3b (GSK3b) in palmitate-stimulated cardiomyocytes. In contrast, inhibition of Akt with an Akt-specific inhibitor MK2206 or blockade of GLP1 receptor (GLP1R) with a competitive antagonist exendin-(9-39) significantly abrogated the GLP1-mediated activation of GSK3b/b-catenin signalling, leading to increased apoptosis in palmitate-stressed cardiomyocytes. Collectively, our results demonstrated for the first time that the attenuated b-catenin signalling may contribute to palmitate-induced cardiomyocyte apoptosis, while GLP1 can protect cardiomyocytes from palmitate-induced apoptosis through

  14. Puquitinib mesylate (XC-302) induces autophagy via inhibiting the PI3K/AKT/mTOR signaling pathway in nasopharyngeal cancer cells.

    Science.gov (United States)

    Wang, Ke-Feng; Yang, Hang; Jiang, Wen-Qi; Li, Su; Cai, Yu-Chen

    2015-12-01

    There are numerous studies that demonstrate the anti-neoplastic activity of phosphatidylinositol 3-kinase (PI3K) inhibitors and the mechanisms of inducing autophagy in cancer cells. The new anticancer drug puquitinib mesylate (XC-302) is a molecular-targeted drug, which suppresses the activity of PI3K directly. However, it remains unclear whether XC‑302 can develop an antitumor effect by inducing autophagy in nasopharyngeal cancer cells. The MTT assay was used to study the anti-proliferative effects of XC-302. Subsequently, autophagy was determined by monodansylcadaverine (MDC) staining, punctate localization of green fluorescent protein (GFP)-light chain 3 (LC3), LC3 protein blotting and electron microscopy. The expression levels of beclin 1, p62, protein kinase B (AKT), phospho (p)‑AKT, mechanistic target of rapamycin (mTOR) and p‑mTOR in XC-302‑induced autophagy were detected. Autophagy inhibition was assayed by 3-methyladenine (3‑MA) or small interfering RNA (siRNA) silencing of beclin 1. XC-302 inhibited the viability of CNE‑2 in a dose-dependent manner and the IC50 of 72 h was 5.2 µmol/l. After cells were exposed to XC-302 for 24 h, MDC-labeled autophagolysosomes were evident in CNE-2 cells by fluorescence microscope. Autophagosomes and autolysosomes were identified by transmission electron microscopy. Following transfection with GFP‑LC3, XC-302 induced a significant accumulation of GFP‑LC3, as monitored by a confocal microscope, which was reduced by 3-MA. XC-302 induced the formation of LC3‑II, increased beclin 1 levels and decreased the expression of p62. Additionally, the expression levels of p‑AKT and p‑mTOR were reduced with the elevation of XC-302. Knockdown of beclin 1 with siRNA or co-treatment with 3-MA enhanced significantly the survival of CNE-2 and promoted the ability of clone formation. XC-302 also induced apoptosis in CNE-2, and when autophagy was inhibited by 3-MA, the apoptosis rate was decreased. The present data

  15. Metformin inhibits age-related centrosome amplification in Drosophila midgut stem cells through AKT/TOR pathway.

    Science.gov (United States)

    Na, Hyun-Jin; Park, Joung-Sun; Pyo, Jung-Hoon; Jeon, Ho-Jun; Kim, Young-Shin; Arking, Robert; Yoo, Mi-Ae

    2015-07-01

    We delineated the mechanism regulating the inhibition of centrosome amplification by metformin in Drosophila intestinal stem cells (ISCs). Age-related changes in tissue-resident stem cells may be closely associated with tissue aging and age-related diseases, such as cancer. Centrosome amplification is a hallmark of cancers. Our recent work showed that Drosophila ISCs are an excellent model for stem cell studies evaluating age-related increase in centrosome amplification. Here, we showed that metformin, a recognized anti-cancer drug, inhibits age- and oxidative stress-induced centrosome amplification in ISCs. Furthermore, we revealed that this effect is mediated via down-regulation of AKT/target of rapamycin (TOR) activity, suggesting that metformin prevents centrosome amplification by inhibiting the TOR signaling pathway. Additionally, AKT/TOR signaling hyperactivation and metformin treatment indicated a strong correlation between DNA damage accumulation and centrosome amplification in ISCs, suggesting that DNA damage might mediate centrosome amplification. Our study reveals the beneficial and protective effects of metformin on centrosome amplification via AKT/TOR signaling modulation. We identified a new target for the inhibition of age- and oxidative stress-induced centrosome amplification. We propose that the Drosophila ISCs may be an excellent model system for in vivo studies evaluating the effects of anti-cancer drugs on tissue-resident stem cell aging.

  16. Short-term psychosocial stress protects photoreceptors from damage via corticosterone-mediated activation of the AKT pathway.

    Science.gov (United States)

    Forkwa, Tembei K; Neumann, Inga D; Tamm, Ernst R; Ohlmann, Andreas; Reber, Stefan O

    2014-02-01

    Apoptotic death of photoreceptors in hereditary retinal degenerations can be prevented by neuroprotective molecules. Here, we report that adrenal glucocorticoids (GC) released during psychosocial stress protect photoreceptors from apoptosis after light damage. Psychosocial stress is known to be the main type of stressor humans are exposed to and was induced here in mice by 10h of chronic subordinate colony housing (CSC). Photoreceptor damage was generated by subsequent exposure to white light. Short-term psychosocial stress prior to illumination significantly reduced the number of apoptotic photoreceptors, an effect that was absent in adrenalectomized (ADX) mice. The neuroprotective effect was completely restored in ADX mice substituted with GC. Moreover, phosphorylation of retinal AKT increased following CSC or exogenous GC treatment, an effect that was again absent in ADX mice exposed to CSC. Finally, inhibition of AKT signaling with triciribine blocked the stress- and GC-mediated neuroprotective effects on photoreceptors. In summary, we provide evidence that 1) short-term psychosocial stress protects photoreceptors from light-induced damage and 2) the protective effect is most likely mediated by GC-induced activation of the AKT signaling pathway.

  17. Marine Cyclotripeptide X-13 Promotes Angiogenesis in Zebrafish and Human Endothelial Cells via PI3K/Akt/eNOS Signaling Pathways

    Directory of Open Access Journals (Sweden)

    Zhong Pei

    2012-06-01

    Full Text Available Cyclotripeptide X-13 is a core of novel marine compound xyloallenoide A isolated from mangrove fungus Xylaria sp. (no. 2508. We found that X-13 dose-dependently induced angiogenesis in zebrafish embryos and in human endothelial cells, which was accompanied by increased phosphorylation of eNOS and Akt and NO release. Inhibition of PI3K/Akt/eNOS by LY294002 or l-NAME suppressed X-13-induced angiogenesis. The present work demonstrates that X-13 promotes angiogenesis via PI3K/Akt/eNOS pathways.

  18. 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

  19. 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.

  20. Dynamic Modeling and Analysis of the Cross-Talk between Insulin/AKT and MAPK/ERK Signaling Pathways

    Science.gov (United States)

    Arkun, Yaman

    2016-01-01

    Feedback loops play a key role in the regulation of the complex interactions in signal transduction networks. By studying the network of interactions among the biomolecules present in signaling pathways at the systems level, it is possible to understand how the biological functions are regulated and how the diseases emerge from their deregulations. This paper identifies the key feedback loops involved in the cross-talk among the insulin-AKT and MAPK/ERK signaling pathways. We developed a mathematical model that can be used to study the steady-state and dynamic behavior of the interactions among these two important signaling pathways. Modeling analysis and simulation case studies identify the key interaction parameters and the feedback loops that determine the normal and disease phenotypes. PMID:26930065

  1. Hydronephrotic urine in the obstructed kidney promotes urothelial carcinoma cell proliferation, migration, invasion through the activation of mTORC2-AKT and ERK signaling pathways.

    Directory of Open Access Journals (Sweden)

    Chi-Hao Chang

    Full Text Available Obstructive nephropathy is the most common presentation of urothelial carcinoma. The role of the urine in the obstructed kidney namely "hydronephrotic urine" in urothelial carcinoma has not been extensively explored. This study aims to evaluate whether hydronephrotic urine in the obstructed kidney could promote urothelial carcinoma. The hydronephrotic urine was collected from the obstructed kidneys of Sprague-Dawley rats induced by different periods of unilateral ureteral obstruction (UUO. By the inhibition of LY294002 and PD184352, we confirm that hydronephrotic urine promotes urothelial carcinoma cell (T24 and immortalized normal urothelial cells (E6 proliferation, migration and invasion in a dose-dependent manner through the activation of the mTORC2-AKT and ERK signaling pathways. Hydronephrotic urine also increases the expression of cyclin-D2, cyclin-B and CDK2. It also decreases the expression of p27 and p21 in both urothelial carcinoma cells and normal urothelial cells. By the protein array study, we demonstrate that many growth factors which promote tumor cell survival and metastasis are over-expressed in a time-dependent manner in the hydronephrotic urine, including beta-FGF, IFN-γ, PDGF-BB, PIGF, TGF-β, VEGF-A, VEGF-D and EGF. These results suggest that hydronephrotic urine promotes normal and malignant urothelial cells proliferation, migration and invasion, through the activation of the mTORC2-AKT and ERK signaling pathways. Further investigation using live animal models of tumor growth may be needed to clarify aspects of these statements.

  2. Oxidative cytotoxic agent withaferin A resensitizes temozolomide-resistant glioblastomas via MGMT depletion and induces apoptosis through Akt/mTOR pathway inhibitory modulation

    Science.gov (United States)

    Grogan, Patrick T.; Sarkaria, Jann N.; Timmermann, Barbara N.; Cohen, Mark S.

    2014-01-01

    Temozolomide (TMZ) has remained the chemotherapy of choice in patients with glioblastoma multiforme (GBM) primarily due to the lack of more effective drugs. Tumors, however, quickly develop resistance to this line of treatment creating a critical need for alternative approaches and strategies to resensitize the cells. Withaferin A (WA), a steroidal lactone derived from several genera of the Solanaceae plant family has previously demonstrated potent anti-cancer activity in multiple tumor models. Here, we examine the effects of WA against TMZ-resistant GBM cells as a monotherapy and in combination with TMZ. WA prevented GBM cell proliferation by dose-dependent G2/M cell cycle arrest and cell death through both intrinsic and extrinsic apoptotic pathways. This effect correlated with depletion of principle proteins of the Akt/mTOR and MAPK survival and proliferation pathways with diminished phosphorylation of Akt, mTOR, and p70 S6K but compensatory activation of ERK1/2. Depletion of tyrosine kinase cell surface receptors c-Met, EGFR, and Her2 was also observed. WA demonstrated induction of N-acetyl-L-cysteine-repressible oxidative stress as measured directly and through a subsequent heat shock response with HSP32 and HSP70 upregulation and decreased HSF1. Finally, pretreatment of TMZ-resistant GBM cells with WA was associated with O6-methylguanine-DNA methyltransferase (MGMT) depletion which potentiated TMZ-mediated MGMT degradation. Combination treatment with both WA and TMZ resulted in resensitization of MGMT-mediated TMZ-resistance but not resistance through mismatch repair mutations. These studies suggest great clinical potential for the utilization of WA in TMZ-resistant GBM as both a monotherapy and a resensitizer in combination with the standard chemotherapeutic agent TMZ. PMID:24718901

  3. TCDD promotes lung tumors via attenuation of apoptosis through activation of the Akt and ERK1/2 signaling pathways.

    Directory of Open Access Journals (Sweden)

    Rong-Jane Chen

    Full Text Available 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD is a multiple-site, multiple-species carcinogen that induces cancer in multiple organs. The molecular mechanisms underlying TCDD-induced lung tumorigenesis remain unclear. In the present study, a two-stage lung tumorigenesis model was established by administrating a single low dose of 4-(methylnitrosamino-1-(3-pyridyl-1-butanone (NNK combined with TCDD to female A/J mice. The results indicated that TCDD combined with low-dose NNK has a significant tumor-promoting effect compared with TCDD or low-dose NNK alone. Resistance to apoptosis is a hallmark of cancer and is thought to be one of the tumor-promoting mechanisms regulated by TCDD. We performed an additional series of experiments in the normal human bronchial epithelial cell line Beas2B cells, in which TCDD was combined with the apoptosis inducer staurosporine. Our in vitro results confirmed that TCDD could rescue cells from apoptosis induced by staurosporine. The inhibition of apoptosis is likely mediated by the activation of the Akt and ERK1/2 pathways, as determined by the effectiveness of pathway-specific inhibitors in abrogating the anti-apoptotic activity of TCDD. In conclusion, we demonstrated that TCDD promoted NNK-induced lung tumorigenesis and revealed that TCDD inhibits staurosporine-induced apoptosis, at least in part, through the Akt and ERK1/2 signaling pathways.

  4. Relaxin in paraventricular nucleus contributes to sympathetic overdrive and hypertension via PI3K-Akt pathway.

    Science.gov (United States)

    Sun, Hai-Jian; Chen, Dan; Han, Ying; Zhou, Ye-Bo; Wang, Jue-Jin; Chen, Qi; Li, Yue-Hua; Gao, Xing-Ya; Kang, Yu-Ming; Zhu, Guo-Qing

    2016-04-01

    Relaxin is recognized as an ovarian polypeptide hormone. Abundant relaxin binding sites are observed in hypothalamic paraventricular nucleus (PVN). This study was conducted to determine the roles and underlying mechanisms of relaxin in the PVN in sympathetic activation and hypertension in spontaneously hypertensive rats (SHR). Experiments were performed in normotensive Wistar-Kyoto rats (WKY) and SHR. Relaxin and its RXFP1 receptors in PVN were up-regulated in SHR. Relaxin-positive neurons existed in both parvocellular and magnocellular parts of the PVN. Presympathetic neurons and AVP neurons in the PVN expressed RXFP1, but not relaxin. Bilateral PVN microinjection of human relaxin-2 increased but anti-relaxin IgG reduced renal sympathetic nerve activity (RSNA), mean arterial pressure (MAP), plasma norepinephrine (NE) and arginine vasopressin (AVP) levels in SHR. The effects of relaxin-2 on RSNA and MAP were abolished by intravenous infusion of ganglionic blocker hexamethonium, and attenuated by AVP V1 receptor antagonist AAVP. Akt phosphorylation was enhanced in SHR, and relaxin-2 stimulated Akt phosphorylation and p85α subunit of PI3K expression. PI3K inhibitor LY294002 or Akt inhibitor MK-2206 abolished the effects of relaxin-2 on the RSNA, MAP and plasma NE, and attenuated the relaxin-2-induced AVP secretion. STAT5a and polymerase II (Pol II) binding to relaxin-promoter were significantly increased in SHR. Chronic PVN infusion of relaxin-2 with osmotic pumps in normal rats induced sympathetic activation, AVP secretion and hypertension accompanied with cardiovascular remodeling. Relaxin in the PVN contributes to sympathetic overdrive and hypertension via PI3K-Akt pathway. PMID:26746861

  5. Alisol B acetate induces apoptosis of SGC7901 cells via mitochondrial and phosphatidylinositol 3-kinases/Akt signaling pathways

    Institute of Scientific and Technical Information of China (English)

    Yong-Hong Xu; Li-Jie Zhao; Yan Li

    2009-01-01

    AIM: To examine the effect of alisol B acetate on the growth of human gastric cancer cell line SGC7901 and its possible mechanism of action. METHODS: The cytotoxic effect of alisol B acetate on SGC7901 cells was measured by 3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Phase-contrast and electron microscopy were used to observe the morphological changes. Cell cycle and mitochondrial transmembrane potential (ΔΨm) were determined by flow cytometry. Western blotting was used to detect the expression of apoptosis-regulated gene Bcl-2, Bax, Apaf-1, caspase-3, caspase-9, Akt, P-Akt and phosphatidylinositol 3-kinases (PI3K). RESULTS: Alisol B acetate inhibited the proliferation of SGC7901 cell line in a time- and dose-dependent manner. PI staining showed that alisol B acetate can change the cell cycle distribution of SGC7901, increase the proportion of cells in G0-G1 phase and decrease the proportion of S phase cells and G2-M phase cells. Alisol B acetate at a concentration of 30 μmol/L induced apoptosis after 24, 48 and 72 h incubation, with occurrence rates of apoptotic cells of 4.36%, 14.42% and 21.16%, respectively. Phase-contrast and electron microscopy revealed that the nuclear fragmentation and chromosomal condensed, cells shrank and attachment loss appeared in the SGC7901 treated with alisol B acetate. Apoptosis of SGC7901 with alisol B acetate. Apoptosis of SGC7901 cells was associated with cell cycle arrest, caspase-3 and caspase-9 activation, loss of mitochondrial membrane potential and up-regulation of the ratio of Bax/Bcl-2 and inhibition of the PI3K/Akt. CONCLUSION: Alisol B acetate exhibits an antiproliferative effect in SGC7901 cells by inducing apoptosis. Apoptosis of SGC7901 cells involves mitochondria-caspase and PI3K/Akt dependent pathways.

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

    Science.gov (United States)

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

    2015-10-27

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

  7. 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.

  8. Silencing Fibronectin Extra Domain A Enhances Radiosensitivity in Nasopharyngeal Carcinomas Involving an FAK/Akt/JNK Pathway

    International Nuclear Information System (INIS)

    Purpose: Fibronectin extra domain A (EDA) is known to play important roles in angiogenesis, lymphangiogenesis, and metastasis in malignant tumors. The present study examined the effect of EDA on the radioresistance potential of nasopharyngeal carcinoma (NPC). Methods and Materials: EDA expression levels in blood samples and tumor tissues of NPC patients were tested by enzyme-linked immunosorbent assay and immunohistochemistry. Radiosensitivity was tested by colony survival assay. Apoptosis was determined by flow cytometry. The expressions of EDA, cleaved caspase 9, cleaved caspase 3, cleaved PARP, Bcl-2, and the levels of phosphorylated FAK, Akt, and JNK were measured by Western blot. Xenografts were used to confirm the effect of EDA on radiosensitivity in vivo. Results: EDA levels in blood samples of advanced NPC patients were much higher than those in early-stage patients. In tumor tissues, the positive expressions of EDA in NPC tumor tissues were shown to be correlated with the differentiation degrees of cancer cells and lymph node metastases. Additionally, the expression of EDA is positively correlated with the expression of antiapoptotic gene (Bcl2), but negatively correlated with the expressions of apoptotic genes (cleaved caspase-3, cleaved caspase-9, cleaved PARP). In vitro, EDA-silenced NPC cells CNE-2 shows substantially enhanced radiosensitivity with lower colony survival and more apoptosis in response to radiation. In vivo, EDA-silenced xenografts were more sensitive to radiation. At the molecular level, FAK/Akt/JNK signaling was demonstrated to be inactivated in EDA-silenced CNE-2 cells. Conclusions: EDA strongly affected the radiosensitivity of NPC cells. FAK/Akt/JNK signaling was found to be a potential signaling mediating EDA function.

  9. Arctigenin, a Potent Ingredient of Arctium lappa L., Induces Endothelial Nitric Oxide Synthase and Attenuates Subarachnoid Hemorrhage-Induced Vasospasm through PI3K/Akt Pathway in a Rat Model

    OpenAIRE

    Chih-Zen Chang; Shu-Chuan Wu; Chia-Mao Chang; Chih-Lung Lin; Aij-Lie Kwan

    2015-01-01

    Upregulation of protein kinase B (PKB, also known as Akt) is observed within the cerebral arteries of subarachnoid hemorrhage (SAH) animals. This study is of interest to examine Arctigenin, a potent antioxidant, on endothelial nitric oxide synthase (eNOS) and Akt pathways in a SAH in vitro study. Basilar arteries (BAs) were obtained to examine phosphatidylinositol-3-kinase (PI3K), phospho-PI3K, Akt, phospho-Akt (Western blot) and morphological examination. Endothelins (ETs) and eNOS evaluatio...

  10. Quercetin 3-O-methyl ether protects FL83B cells from copper induced oxidative stress through the PI3K/Akt and MAPK/Erk pathway

    Energy Technology Data Exchange (ETDEWEB)

    Tseng, Hsiao-Ling, E-mail: lily1001224@gmail.com [Department of Life Sciences, Tzu Chi University, Hualien, Taiwan (China); Li, Chia-Jung, E-mail: 97751101@stmail.tcu.edu.tw [Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan (China); Huang, Lin-Huang, E-mail: yg1236@yahoo.com.tw [School of Medicine, Institute of Traditional Medicine, National Yang-Ming University, Taipei, Taiwan (China); Chen, Chun-Yao, E-mail: cychen@mail.tcu.edu.tw [Department of Life Sciences, Tzu Chi University, Hualien, Taiwan (China); Tsai, Chun-Hao, E-mail: 100726105@stmail.tcu.edu.tw [Department of Life Sciences, Tzu Chi University, Hualien, Taiwan (China); Lin, Chun-Nan, E-mail: lincna@cc.kmu.edu.tw [Faculty of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan (China); Department of Biological Science and Technology, School of Medicine, China Medical University, Taichung, Taiwan (China); Hsu, Hsue-Yin, E-mail: hsueyin@mail.tcu.edu.tw [Department of Life Sciences, Tzu Chi University, Hualien, Taiwan (China)

    2012-10-01

    Quercetin is a bioflavonoid that exhibits several biological functions in vitro and in vivo. Quercetin 3-O-methyl ether (Q3) is a natural product reported to have pharmaceutical activities, including antioxidative and anticancer activities. However, little is known about the mechanism by which it protects cells from oxidative stress. This study was designed to investigate the mechanisms by which Q3 protects against Cu{sup 2+}-induced cytotoxicity. Exposure to Cu{sup 2+} resulted in the death of mouse liver FL83B cells, characterized by apparent apoptotic features, including DNA fragmentation and increased nuclear condensation. Q3 markedly suppressed Cu{sup 2+}-induced apoptosis and mitochondrial dysfunction, characterized by reduced mitochondrial membrane potential, caspase-3 activation, and PARP cleavage, in Cu{sup 2+}-exposed cells. The involvement of PI3K, Akt, Erk, FOXO3A, and Mn-superoxide dismutase (MnSOD) was shown to be critical to the survival of Q3-treated FL83B cells. The liver of both larval and adult zebrafish showed severe damage after exposure to Cu{sup 2+} at a concentration of 5 μM. Hepatic damage induced by Cu{sup 2+} was reduced by cotreatment with Q3. Survival of Cu{sup 2+}-exposed larval zebrafish was significantly increased by cotreatment with 15 μM Q3. Our results indicated that Cu{sup 2+}-induced apoptosis in FL83B cells occurred via the generation of ROS, upregulation and phosphorylation of Erk, overexpression of 14-3-3, inactivation of Akt, and the downregulation of FOXO3A and MnSOD. Hence, these results also demonstrated that Q3 plays a protective role against oxidative damage in zebrafish liver and remarked the potential of Q3 to be used as an antioxidant for hepatocytes. Highlights: ► Protective effects of Q3 on Cu{sup 2+}-induced oxidative stress in vitro and in vivo. ► Cu{sup 2+} induced apoptosis in FL83B cells via ROS and the activation of Erk. ► Q3 abolishes Cu{sup 2+}-induced apoptosis through the PI3K/Akt and MAPK

  11. Synthetic sulfoglycolipids targeting the serine-threonine protein kinase Akt.

    Science.gov (United States)

    Costa, Barbara; Dangate, Milind; Vetro, Maria; Donvito, Giulia; Gabrielli, Luca; Amigoni, Loredana; Cassinelli, Giuliana; Lanzi, Cinzia; Ceriani, Michela; De Gioia, Luca; Filippi, Giulia; Cipolla, Laura; Zaffaroni, Nadia; Perego, Paola; Colombo, Diego

    2016-08-15

    The serine-threonine protein kinase Akt, also known as protein kinase B, is a key component of the phosphoinositide 3-kinase (PI3K)-Akt-mTOR axis. Deregulated activation of this pathway is frequent in human tumors and Akt-dependent signaling appears to be critical in cell survival. PI3K activation generates 3-phosphorylated phosphatidylinositols that bind Akt pleckstrin homology (PH) domain. The blockage of Akt PH domain/phosphoinositides interaction represents a promising approach to interfere with the oncogenic potential of over-activated Akt. In the present study, phosphatidyl inositol mimics based on a β-glucoside scaffold have been synthesized as Akt inhibitors. The compounds possessed one or two lipophilic moieties of different length at the anomeric position of glucose, and an acidic or basic group at C-6. Docking studies, ELISA Akt inhibition assays, and cellular assays on different cell models highlighted 1-O-octadecanoyl-2-O-β-d-sulfoquinovopyranosyl-sn-glycerol as the best Akt inhibitor among the synthesized compounds, which could be considered as a lead for further optimization in the design of Akt inhibitors.

  12. Dormancy of Cancer Cells with Suppression of AKT Activity Contributes to Survival in Chronic Hypoxia

    OpenAIRE

    Hiroko Endo; Hiroaki Okuyama; Masayuki Ohue; Masahiro Inoue

    2014-01-01

    A hypoxic microenvironment in tumors has been recognized as a cause of malignancy or resistance to various cancer therapies. In contrast to recent progress in understanding the acute response of cancer cells to hypoxia, the characteristics of tumor cells in chronic hypoxia remain elusive. We have identified a pancreatic cancer cell line, AsPC-1, that is exceptionally able to survive for weeks under 1% oxygen conditions while most tested cancer cell lines die after only some days under these c...

  13. miR-590-5p regulates gastric cancer cell growth and chemosensitivity through RECK and the AKT/ERK pathway

    Science.gov (United States)

    Shen, Bo; Yu, Shaorong; Zhang, Yan; Yuan, Yuan; Li, Xiaoyou; Zhong, Jian; Feng, Jifeng

    2016-01-01

    Background The aim of this study was to determine the role of miRNA-590-5p in gastric cancer (GC) progression. Methods Quantitative real-time polymerase chain reaction was performed to measure endogenous miR-590-5p levels in GC cells and tissues. Overexpression or knockdown of miR-590-5p in GC cells was performed by transfection with mimics or an inhibitor, respectively. MTT, matrigel transwell, and Western blot assays were used to assess the effects of miR-590-5p on cell proliferation, invasion, chemosensitivity of GC cells, and the AKT pathway, respectively. In silico prediction and luciferase reporter activity were used to identify potential targets of miR-590-5p. A xenograft model was also established to evaluate the function of miR-590-5p in vivo. Results The expression of miR-590-5p was significantly increased in GC cells and tissues, and upregulated miR-590-5p was associated with increased tumor size, lymph node metastasis, and poor survival. Overexpression of miR-590-5p promoted cell proliferation and invasion and reduced the sensitivity of GC cells to cisplatin and paclitaxel. In contrast, inhibition of miR-590-5p had the opposite effects on GC cells. RECK was identified as a direct target of miR-590-5p. Knockdown of RECK accelerated cell proliferation and motility and decreased the drug sensitivity. Furthermore, reintroduction of RECK inhibited the oncogenic effects of miR-590-5p by suppressing cell proliferation and invasion and increasing drug sensitivity. We found that the AKT/ERK and STAT3 signaling pathways were activated by miR-590-5p overexpression. The chemoresistance of miR-590-5p was also verified by in vivo analysis. Conclusion In summary, we suggest that the miR-590-5p/RECK/AKT axis contributes to GC and may serve as a promising therapeutic target for treatment. PMID:27757042

  14. MicroRNA-520a attenuates proliferation of Raji cells through inhibition of AKT1/NF-κB and PERK/eIF2α signaling pathway.

    Science.gov (United States)

    Wang, Xiaojuan; Wang, Pei; Zhu, Yan; Zhang, Zhi; Zhang, Jinqian; Wang, Hongwei

    2016-09-01

    Burkitt's lymphoma (BL) is a fast growing cancer of the human lymphatic system, and an extremely invasive B-cell non-Hodgkin's lymphoma. We explored the mechanism of apoptosis in Raji cells associated with the post-transcriptional regulation factors. To confirm that the predicted microRNA-520a (miR-520a) is matched with AKT1, 3' untranslated region (UTR) luciferase activity of AKT1 was used in the assessment. In the presence of the mimics or inhibitors of miR-520a, cell function of Raji, such as proliferation, growth and apoptosis were analyzed. The expression of endoplasmic reticulum (ER) stress‑related proteins were examined. Luciferase reporter analysis showed that miR‑520a leads to decreased activity of luciferase gene fused with AKT1 3'UTR. Therefore, AKT1 is a direct target of miR‑520a. Our data indicated that the mimics of miR‑520a inhibited growth, proliferation of Raji cells and promoted its apoptosis, which was related to downregulation of AKT1, NF‑κB and ER stress response mediated by PERK/eIF2α pathway. On the contrary, the inhibitors of miR‑520a promoted growth, proliferation of Raji cells and inhibited its apoptosis, which was related to AKT1/NF‑κB and PERK/eIF2α pathway. We identified miR‑520a, which specifically binds to AKT1 mRNA 3'UTR. miR‑520a is a crucial mediator for proliferation and ER stress in Raji cells through regulating the AKT1/NF‑κB or PERK/eIF2α signaling pathway. Our findings suggest that targeting miR‑520a is a promising therapeutic strategy in BL. PMID:27461820

  15. Role of mechanical strain-activated PI3K/Akt signaling pathway in pelvic organ prolapse.

    Science.gov (United States)

    Li, Bing-Shu; Guo, Wen-Jun; Hong, Li; Liu, Yao-Dan; Liu, Cheng; Hong, Sha-Sha; Wu, De-Bin; Min, Jie

    2016-07-01

    Mechanical loading on pelvic supports contributes to pelvic organ prolapse (POP). However, the underlying mechanisms remain to be elucidated. Our previous study identified that mechanical strain induced oxidative stress (OS) and promoted apoptosis and senescence in pelvic support fibroblasts. The aim of the present study is to investigate the molecular signaling pathway linking mechanical force with POP. Using a four‑point bending device, human uterosacral ligament fibroblasts (hUSLF) were exposed to mechanical tensile strain at a frequency of 0.3 Hz and intensity of 5333 µε, in the presence or absence of LY294002. The applied mechanical strain on hUSLF resulted in apoptosis and senescence, and decreased expression of procollagen type I α1. Mechanical strain activated phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/Akt signaling and resulted in downregulated expression of glutathione peroxidase 1 and Mn‑superoxide dismutase, and accumulation of intracellular reactive oxygen species. These effects were blocked by administration of LY294002. Furthermore, it was demonstrated that PI3K/Akt was activated in the uterosacral ligaments of POP patients, and that OS was increased and collagen type I production reduced. The results from the present study suggest that mechanical strain promotes apoptosis and senescence, and reduces collagen type I production via activation of PI3K/Akt-mediated OS signaling pathway in hUSLF. This process may be involved in the pathogenesis of POP as it results in relaxation and dysfunction of pelvic supports. PMID:27176043

  16. In vivo treatment with diphenyl ditelluride induces neurodegeneration in striatum of young rats: Implications of MAPK and Akt pathways

    Energy Technology Data Exchange (ETDEWEB)

    Heimfarth, Luana; Loureiro, Samanta Oliveira; Dutra, Márcio Ferreira; Andrade, Cláudia; Pettenuzzo, Letícia; Guma, Fátima T. Costa Rodrigues; Gonçalves, Carlos Alberto Saraiva [Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, UFRGS, Porto Alegre, RS (Brazil); Batista Teixeira da Rocha, João [Departamento de Química, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, RS Brazil (Brazil); Pessoa-Pureur, Regina, E-mail: rpureur@ufrgs.br [Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, UFRGS, Porto Alegre, RS (Brazil)

    2012-10-15

    In the present report 15 day-old Wistar rats were injected with 0.3 μmol of diphenyl ditelluride (PhTe){sub 2}/kg body weight and parameters of neurodegeneration were analyzed in slices from striatum 6 days afterwards. We found hyperphosphorylation of intermediate filament (IF) proteins from astrocyte (glial fibrillary acidic protein—GFAP and vimentin) and from neuron (low-, medium- and high molecular weight neurofilament subunits: NF-L, NF-M and NF-H, respectively) and increased MAPK (Erk, JNK and p38MAPK) as well as PKA activities. The treatment induced reactive astrogliosis in the striatum, evidenced by increased GFAP and vimentin immunocontent as well as their mRNA overexpression. Also, (PhTe){sub 2} significantly increased the propidium iodide (PI) positive cells in NeuN positive population without altering PI incorporation into GFAP positive cells, indicating that in vivo exposure to (PhTe){sub 2} provoked neuronal damage. Immunohistochemistry showed a dramatic increase of GFAP staining characteristic of reactive astrogliosis. Moreover, increased caspase 3 in (PhTe){sub 2} treated striatal slices suggested apoptotic cell death. (PhTe){sub 2} exposure decreased Akt immunoreactivity, however phospho-GSK-3-β (Ser9) was unaltered, suggesting that this kinase is not directly implicated in the neurotoxicity of this compound. Therefore, the present results shed light into the mechanisms of (PhTe){sub 2}-induced neurodegeneration in rat striatum, evidencing a critical role for the MAPK and Akt signaling pathways and disruption of cytoskeletal homeostasis, which could be related with apoptotic neuronal death and astrogliosis. -- Highlights: ► Diphenyl ditelluride causes apoptotic neuronal death in the striatum of young rats. ► Diphenyl ditelluride causes reactive astrogliosis in the striatum of rats. ► Diphenyl ditelluride disrupts the homeostasis of the cytoskeleton of the striatum. ► The actions of diphenyl ditelluride are mediated by MAPK and Akt

  17. 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.

  18. Renal cortical hexokinase and pentose phosphate pathway activation through the EGFR/Akt signaling pathway in endotoxin-induced acute kidney injury.

    Science.gov (United States)

    Smith, Joshua A; Stallons, L Jay; Schnellmann, Rick G

    2014-08-15

    While disruption of energy production is an important contributor to renal injury, metabolic alterations in sepsis-induced AKI remain understudied. We assessed changes in renal cortical glycolytic metabolism in a mouse model of sepsis-induced AKI. A specific and rapid increase in hexokinase (HK) activity (∼2-fold) was observed 3 h after LPS exposure and maintained up to 18 h, in association with a decline in renal function as measured by blood urea nitrogen (BUN). LPS-induced HK activation occurred independently of HK isoform expression or mitochondrial localization. No other changes in glycolytic enzymes were observed. LPS-mediated HK activation was not sufficient to increase glycolytic flux as indicated by reduced or unchanged pyruvate and lactate levels in the renal cortex. LPS-induced HK activation was associated with increased glucose-6-phosphate dehydrogenase activity but not glycogen production. Mechanistically, LPS-induced HK activation was attenuated by pharmacological inhibitors of the EGF receptor (EGFR) and Akt, indicating that EGFR/phosphatidylinositol 3-kinase/Akt signaling is responsible. Our findings reveal LPS rapidly increases renal cortical HK activity in an EGFR- and Akt-dependent manner and that HK activation is linked to increased pentose phosphate pathway activity.

  19. Immunohistochemical Analysis of the Activation Status of the Akt/mTOR/pS6 Signaling Pathway in Oral Lichen Planus

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    Georgios Prodromidis

    2013-01-01

    Full Text Available Introduction. Aberrations of the Akt/mTOR/pS6 pathway have been linked to various types of human cancer, including oral squamous cell carcinoma (OSCC. The purpose of this study was to evaluate the activation status of Akt, mTOR, and pS6 in oral lichen planus (OLP in comparison with oral premalignant and malignant lesions and normal oral mucosa (NM. Materials and Methods. Immunohistochemistry for p-Akt, p-mTOR, and phospho-pS6 was performed in 40 OLP, 20 oral leukoplakias (OL, 10 OSCC, and 10 control samples of NM. Results. Nuclear p-Akt expression was detected in the vast majority of cases in all categories, being significantly higher in OL. Cytoplasmic p-Akt and p-mTOR staining was present only in a minority of OLP cases, being significantly lower compared to OL and OSCC. Phospho-pS6 showed cytoplasmic positivity in most OLP cases, which however was significantly lower compared to OL and OSCC. Conclusions. Overall, cytoplasmic p-Akt, p-mTOR, and phospho-pS6 levels appear to be significantly lower in OLP compared to OL and OSCC. However, the expression of these molecules in a subset of OLP cases suggests that activation of Akt/mTOR/pS6 may occur in the context of OLP, possibly contributing to the premalignant potential of individual cases.

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

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    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.

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

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    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. Andrographolide inhibits hypoxia-inducible factor-1 through phosphatidylinositol 3-kinase/AKT pathway and suppresses breast cancer growth

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    Li J

    2015-02-01

    Full Text Available Jie Li,1 Chao Zhang,1 Hongchuan Jiang,1 Jiao Cheng21Department of General Surgery, 2Department of Gynaecology and Obstetrics, Beijing Chao-Yang Hospital, Beijing, People’s Republic of ChinaAbstract: Hypoxia-inducible factor-1 (HIF-1 is a master regulator of the transcriptional response to hypoxia. HIF-1α is one of the most compelling anticancer targets. Andrographolide (Andro was newly identified to inhibit HIF-1 in T47D cells (a half maximal effective concentration [EC50] of 1.03×10-7 mol/L, by a dual-luciferase reporter assay. It suppressed HIF-1α protein and gene accumulation, which was dependent on the inhibition of upstream phosphatidylinositol 3-kinase (PI3K/AKT pathway. It also abrogated the expression of HIF-1 target vascular endothelial growth factor (VEGF gene and protein. Further, Andro inhibited T47D and MDA-MB-231 cell proliferation and colony formation. In addition, it exhibited significant in vivo efficacy and antitumor potential against the MDA-MB-231 xenograft in nude mice. In conclusion, these results highlighted the potential effects of Andro, which inhibits HIF-1, and hence may be developed as an antitumor agent for breast cancer therapy in future.Keywords: Andrographolide (Andro, HIF-1α, inhibit, breast cancer, hypoxia, PI3k/AKT/mTOR pathway

  3. Dioscin-induced autophagy mitigates cell apoptosis through modulation of PI3K/Akt and ERK and JNK signaling pathways in human lung cancer cell lines.

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    Hsieh, Ming-Ju; Tsai, Te-Lung; Hsieh, Yih-Shou; Wang, Chau-Jong; Chiou, Hui-Ling

    2013-11-01

    Our previous study has revealed that dioscin, a compound with anti-inflammatory, lipid-lowering, anticancer and hepatoprotective effects, may induce autophagy in hepatoma cells. Autophagy is a lysosomal degradation pathway that is essential for cell survival and tissue homeostasis. In this study, the role of autophagy and related signaling pathways during dioscin-induced apoptosis in human lung cancer cells was investigated. Results from 4'-6-diamidino-2-phenylindole and annexin-V/PI double-staining assay showed that caspase-3- and caspase-8-dependent, and dose-dependent apoptoses were detected after a 24-h dioscin treatment. Meanwhile, autophagy was detected as early as 12 h after an exposure to low-dose dioscin, as indicated by an up-regulated expression of LC3-II and beclin-1 proteins. Blockade of autophagy with bafilomycin A1 or 3-methyladenine sensitized the A549 and H1299 cells to apoptosis. Treatment of A549 and H1299 cells with dioscin caused a dose-dependent increase in ERK1/2 and JNK1/2 activity, accompanied with a decreased PI3K expression and decreased phosphorylation of Akt and mTOR. Taken together, this study demonstrated for the first time that autophagy occurred earlier than apoptosis during dioscin-induced human lung cancer cell line apoptosis. Dioscin-induced autophagy via ERK1/2 and JNK1/2 pathways may provide a protective mechanism for cell survival against dioscin-induced apoptosis to act as a cytoprotective reaction. PMID:23552851

  4. Hypoxic Preconditioning Inhibits Hypoxia-induced Apoptosis of Cardiac Progenitor Cells via the PI3K/Akt-DNMT1-p53 Pathway.

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    Xu, Rongfeng; Sun, Yuning; Chen, Zhongpu; Yao, Yuyu; Ma, Genshan

    2016-01-01

    Research has demonstrated that hypoxic preconditioning (HP) can enhance the survival and proliferation of cardiac progenitor cells (CPCs); however, the underlying mechanisms are not fully understood. Here, we report that HP of c-kit (+) CPCs inhibits p53 via the PI3K/Akt-DNMT1 pathway. First, CPCs were isolated from the hearts of C57BL/6 mice and further purified by magnetic-activated cell sorting. Next, these cells were cultured under either normoxia (H0) or HP for 6 hours (H6) followed by oxygen-serum deprivation for 24 hours (24h). Flow cytometric analysis and MTT assays revealed that hypoxia-preconditioned CPCs exhibited an increased survival rate. Western blot and quantitative real-time PCR assays showed that p53 was obviously inhibited, while DNMT1 and DNMT3β were both significantly up-regulated by HP. Bisulphite sequencing analysis indicated that DNMT1 and DNMT3β did not cause p53 promoter hypermethylation. A reporter gene assay and chromatin immunoprecipitation analysis further demonstrated that DNMT1 bound to the promoter locus of p53 in hypoxia-preconditioned CPCs. Together, these observations suggest that HP of CPCs could lead to p53 inhibition by up-regulating DNMT1 and DNMT3β, which does not result in p53 promoter hypermethylation, and that DNMT1 might directly repress p53, at least in part, by binding to the p53 promoter locus. PMID:27488808

  5. Cardiac Shock Wave Therapy Attenuates H9c2 Myoblast Apoptosis by Activating the AKT Signal Pathway

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    Weiwei Yu

    2014-04-01

    Full Text Available Background: Previous studies have demonstrated that Cardiac Shock Wave Therapy (CSWT improves myocardial perfusion and cardiac function in a porcine model of chronic myocardial ischemia and also ameliorates myocardial ischemia in patients with severe coronary artery disease (CAD. Apoptosis plays a key role in ischemic myocardial pathogenesis. However, it remains unclear whether CSWT is beneficial for ischemia/hypoxia (I/H-induced myocardial cell apoptosis and by which mechanism CSWT could improve heart function. We put forward the hypothesis that CSWT might protect heart function during ischemia/hypoxia by decreasing apoptosis. Methods: We generated ischemia/hypoxia (I/H-induced apoptosis in the H9c2 myoblast cell line to examine the CSWT function and possible mechanisms. H9c2 cells were treated under hypoxic serum-starved conditions for 24 h and then treated with or without CSWT (500 shots, 0.06, 0.09, 0.12mJ/mm2. The apoptotic cell rate was determined by flow cytometry assay, cell viability was examined by the MTT assay, nuclear fragmentation was detected by Hoechst 33342 staining, and the mitochondrial-mediated intrinsic pathway of apoptosis was assessed by the expression of Bax and Bcl-2 protein and Caspase3 activation. Results: First, apoptosis could be induced by ischemia/hypoxia in H9c2 cells. Second, CSWT attenuates the cell death and decreases the H9c2 cell apoptosis rate induced by ischemia and hypoxia. Third, CSWT suppresses the expression of apoptosis molecules that regulate the intrinsic pathway of apoptosis in H9c2 cells. Fourth, CSWT increases the phosphorylation of AKT, which indicates the activation of the PI3K-AKT pathway. Conclusions: These results indicate that CSWT exerts a protective effect against I/H-induced cell death, potentially by preventing the activation of components of the mitochondrial-dependent intrinsic apoptotic pathway. We also demonstrate that the PI3K-Akt pathway may be involved in the CSWT effects on

  6. Isorhamnetin inhibits cell proliferation and induces apoptosis in breast cancer via Akt and mitogen‑activated protein kinase kinase signaling pathways.

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    Hu, Shan; Huang, Liming; Meng, Liwei; Sun, He; Zhang, Wei; Xu, Yingchun

    2015-11-01

    Breast cancer is the most common cause of female cancer-associated mortality. Although treatment options, including chemotherapy, radiotherapy and surgery have led to a decline in the mortality rates associated with breast cancer, drug resistance remains one of the predominant causes for poor prognosis and high recurrence rates. The present study investigated the potential effects of the natural product, isorhamnetin on breast cancer, and examined the effects of isorhamnetin on the Akt/mammalian target of rapamycin (mTOR) and the mitogen-activated protein kinase (MAPK)/MAPK kinase (MEK) signaling cascades, which are two important signaling pathways for endocrine therapy resistance in breast cancer. The results of the present study indicate that isorhamnetin inhibits cell proliferation and induces cell apoptosis. In addition, isorhamnetin was observed to inhibit the Akt/mTOR and the MEK/extracellular signal-regulated kinase phosphorylation cascades. The inhibition of these two signaling pathways was attenuated by the two Akt and MEK1 inhibitors, but not by the nuclear factor-κB inhibitor. Furthermore, epidermal growth factor inhibited the effects of isorhamnetin via activation of the Akt and MEK signaling pathways. These results indicate that isorhamnetin exhibits antitumor effects in breast cancer, which are mediated by the Akt and MEK signaling pathways. PMID:26502751

  7. 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

  8. Cell Type-Specific Activation of AKT and ERK Signaling Pathways by Small Negatively-Charged Magnetic Nanoparticles

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    Rauch, Jens; Kolch, Walter; Mahmoudi, Morteza

    2012-11-01

    The interaction of nanoparticles (NPs) with living organisms has become a focus of public and scientific debate due to their potential wide applications in biomedicine, but also because of unwanted side effects. Here, we show that superparamagnetic iron oxide NPs (SPIONs) with different surface coatings can differentially affect signal transduction pathways. Using isogenic pairs of breast and colon derived cell lines we found that the stimulation of ERK and AKT signaling pathways by SPIONs is selectively dependent on the cell type and SPION type. In general, cells with Ras mutations respond better than their non-mutant counterparts. Small negatively charged SPIONs (snSPIONs) activated ERK to a similar extent as epidermal growth factor (EGF), and used the same upstream signaling components including activation of the EGF receptor. Importantly, snSPIONs stimulated the proliferation of Ras transformed breast epithelial cells as efficiently as EGF suggesting that NPs can mimic physiological growth factors.

  9. Vitamin K2 regression aortic calcification induced by warfarin via Gas6/Axl survival pathway in rats.

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    Jiang, Xiaoyu; Tao, Huiren; Qiu, Cuiting; Ma, Xiaolei; Li, Shan; Guo, Xian; Lv, Anlin; Li, Huan

    2016-09-01

    The aim of this study was to investigate the effect of vitamin K2 on aortic calcification induced by warfarin via Gas6/Axl survival pathway in rats. A calcification model was established by administering 3mg/g warfarin to rats. Rats were divided into 9 groups: control group (0W, 4W, 6W and 12W groups), 4W calcification group, 6W calcification group, 12W calcification group, 6W calcification+6W normal group and 6W calcification+6W vitamin K2 group. Alizarin red S staining measured aortic calcium depositions; alkaline phosphatase activity in serum was measured by a kit; apoptosis was evaluated by TUNEL assay; protein expression levels of Gas6, Axl, phosphorylated Akt (p-Akt), and Bcl-2 were determined by western blotting. The calcium content, calcium depositions, ALP activity and apoptosis were significantly higher in the calcification groups than control group. Gas6, Axl, p-Akt and Bcl-2 expression was lower in the calcification group than control group. 100μg/g vitamin K2 treatment decreased calcium depositions, ALP activity and apoptosis significantly, but increased Gas6, Axl, p-Akt and Bcl-2 expression. 100μg/g vitamin K2 reversed 44% calcification. Pearson correlation analysis showed a positive correlation between formation calcification and apoptosis (R(2)=0.8853, Pvitamin K2 can inhibit warfarin-induced aortic calcification and apoptosis. The regression of aortic calcification by vitamin K2 involved the Gas6/Axl axis. This data may provide a theoretical basis for future clinical treatments for aortic calcification. PMID:27212383

  10. Helicobacter pylori CagA induces tumor suppressor gene hypermethylation by upregulating DNMT1 via AKT-NFκB pathway in gastric cancer development.

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    Zhang, Bao-Gui; Hu, Lei; Zang, Ming De; Wang, He-Xiao; Zhao, Wei; Li, Jian-Fang; Su, Li-Ping; Shao, Zhifeng; Zhao, Xiaodong; Zhu, Zheng-Gang; Yan, Min; Liu, Bingya

    2016-03-01

    Methylation of CpG islands in tumor suppressor gene prompter is one of the most characteristic abnormalities in Helicobacter pylori (HP)-associated gastric carcinoma (GC). Here, we investigated the pathogenic and molecular mechanisms underlying hypermethylation of tumor suppressor genes in HP induced GC development. We found that tumor suppressor genes hypermethylation, represented by MGMT, positively correlated with CagA in clinical specimens, gastric tissues from HP infected C57 mice and GC cell lines transfected by CagA or treated by HP infection. CagA enhanced PDK1 and AKT interaction and increased AKT phosphorylation. The P-AKT subsequent activated NFκB, which then bound to DNMT1 promoter and increased its expression. Finally, the upregulated DNMT1 promoted tumor suppressor genes hypermethylation with MGMT as a representative. In conclusion, CagA increased tumor suppressor genes hypermethylation via stimulating DNMT1 expression through the AKT-NFκB pathway. PMID:26848521

  11. Hydrogen Sulfide Inhibits Abnormal Proliferation of Lymphocytes via AKT/GSK3β Signal Pathway in Systemic Lupus Erythematosus Patients

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    Yanfang Han

    2013-05-01

    Full Text Available Background/Aim: The abnormal activation of the AKT/GSK3β signal pathway in lymphocytes from systemic lupus erythematosus (SLE patients plays an important role in the pathogenesis of the disease. Recently Hydrogen sulfide (H2S has been recognized as a crucial gaseous signaling molecule, involved in regulation of cell proliferation. However, the role of H2S in regulating the abnormal activation of lymphocytes from SLE patients has not been established. This study was conducted to investigate the effect of H2S on lymphocytes and to explore the mechanisms involved. Methods: The lymphocytes were isolated from SLE patients with or without renal disease and healthy controls. The cells were treated as indicated in each experiment. Cell viability was analyzed by CCK-8. Cell cycle distribution was determined by flow cytometry. Western blot was used to detect the expression of phosphorylated AKT (ser473, GSK3β (ser9 and CDK2, p27Kip1 and p21WAF1/CIP1. Results: Our findings showed that proliferation of lymphocytes was stimulated following treatment with NaHS (a H2S donor at low NaHS concentrations (2mM. Similar results were observed using GYY4137, which is a slow-releasing H2S donor. Pretreatment of lymphocytes from SLE patients with NaHS at high concentrations prior to exposure to phytohemagglutinin (PHA significantly attenuated proliferation, evidenced by decrease in cell viability and S phase distribution of cell cycle. Pretreatment with NaHS decreased PHA-induced expression of CDK2, phosphorylation levels of AKT (ser473 and GSK3β (ser9 and increased the expression of p27Kip1 and p21WAF1/CIP1. Moreover, pretreatment with NaHS blunted the stimulation of SLE lymphocyte proliferation by GSK3β inhibitor lithium chloride. Conclusion: These results demonstrate that H2S inhibits the abnormal activation of lymphocytes from SLE patients throuqh the AKT/GSK3β signal pathway.

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

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    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.

  13. Lewis y antigen promotes the proliferation of ovarian carcinoma-derived RMG-I cells through the PI3K/Akt signaling pathway

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    Cong Jianping

    2009-12-01

    Full Text Available Abstract Background Lewis y antigen is difucosylated oligosaccharide and is carried by glycoconjugates at cell surface. Elevated expression of Lewis y has been found in 75% of ovarian tumor, and the high expression level is correlated to the tumor's pathological staging and prognosis. This study was to investigate the effect and the possible mechanism of Lewis y on the proliferation of human ovarian cancer cells. Methods We constructed a plasmid encoding α1,2-fucosyltransferase (α1,2-FT gene and then transfected it into ovarian carcinoma-derived RMG-I cells with lowest Lewis y antigen expression level. Effect of Lewis y on cell proliferation was assessed after transfection. Changes in cell survival and signal transduction were evaluated after α-L-fucosidase, anti-Lewis y antibody and phosphatidylinositol 3-kinase (PI3K inhibitor treatment. Results Our results showed that the levels of α1,2-FT gene and Lewis y increased significantly after transfection. The cell proliferation of ovarian carcinoma-derived RMG-I cells sped up as the Lewis y antigen was increased. Both of α-L-fucosidase and anti-Lewis y antibody inhibited the cell proliferation. The phosphorylation level of Akt was apparently elevated in Lewis y-overexpressing cells and the inhibitor of PI3K, LY294002, dramatically inhibited the growth of Lewis y-overexpressing cells. In addition, the phosphorylation intensity and difference in phosphorylation intensity between cells with different expression of α1,2-FT were attenuated significantly by the monoantibody to Lewis y and by the PI3K inhibitor LY294002. Conclusions Increased expression of Lewis y antigen plays an important role in promoting cell proliferation through activating PI3K/Akt signaling pathway in ovarian carcinoma-derived RMG-I cells. Inhibition of Lewis y expression may provide a new therapeutic approach for Lewis y positive ovarian cancer.

  14. Age-dependent Accumulation of Soluble Amyloid β (Aβ) Oligomers Reverses the Neuroprotective Effect of Soluble Amyloid Precursor Protein-α (sAPPα) by Modulating Phosphatidylinositol 3-Kinase (PI3K)/Akt-GSK-3β Pathway in Alzheimer Mouse Model*

    OpenAIRE

    Jimenez, Sebastian; Torres, Manuel; Vizuete, Marisa; Sanchez-Varo, Raquel; Sanchez-Mejias, Elisabeth; Trujillo-Estrada, Laura; Carmona-Cuenca, Irene; Caballero, Cristina; Ruano, Diego; Gutierrez, Antonia; Vitorica, Javier

    2011-01-01

    Neurotrophins, activating the PI3K/Akt signaling pathway, control neuronal survival and plasticity. Alterations in NGF, BDNF, IGF-1, or insulin signaling are implicated in the pathogenesis of Alzheimer disease. We have previously characterized a bigenic PS1×APP transgenic mouse displaying early hippocampal Aβ deposition (3 to 4 months) but late (17 to 18 months) neurodegeneration of pyramidal cells, paralleled to the accumulation of soluble Aβ oligomers. We hypothesized that PI3K/Akt/GSK-3β s...

  15. Ischemic postconditioning attenuates liver warm ischemia-reperfusion injury through Akt-eNOS-NO-HIF pathway

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    Li Ping Y

    2011-10-01

    Full Text Available Abstract Background Ischemic postconditioning (IPO has been demonstrated to attenuate ischemia/reperfusion (I/R injury in the heart and brain, its roles to liver remain to be defined. The study was undertaken to determine if IPO would attenuate liver warm I/R injury and its protective mechanism. Methods Mice were divided into sham, I/R, IPO+I/R (occlusing the porta hepatis for 60 min, then treated for three cycles of 10 sec brief reperfusion consecutively, followed by a persistent reperfusion; L-NAME+ sham (L-NAME, 16 mg/kg, i.v., 5 min before repefusion; L-NAME+I/R; and L-NAME+ IPO. Blood flow of caudate and left lobe of the liver was blocked. Functional and morphologic changes of livers were evaluated. Contents of nitric oxide, eNOS and iNOS in serum were assayed. Concentration of eNOS, iNOS, malondialdehyde (MDA and activity of superoxide dismutase (SOD in hepatic tissue were also measured. Expressions of Akt, p-Akt and HIF-1α protein were determined by western blot. Expressions of TNF-α and ICAM-1 were measured by immunohistochemistry and RT-PCR. Results IPO attenuated the dramatically functional and morphological injuries. The levels of ALT was significantly reduced in IPO+I/R group (p Conclusions We found that IPO increased the content of NO and attenuated the overproduction of ROS and I/R-induced inflammation. Increased NO contents may contribute to increasing HIF-1α level, and HIF-1α and NO would simultaneously protect liver from I/R injury. These findings suggested IPO may have the therapeutic potential through Akt-eNOS-NO-HIF pathway for the better management of liver I/R injury.

  16. 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.

  17. Isorhynchophylline Protects PC12 Cells Against Beta-Amyloid-Induced Apoptosis via PI3K/Akt Signaling Pathway

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    Yan-Fang Xian

    2013-01-01

    Full Text Available The neurotoxicity of amyloid-β (Aβ has been implicated as a critical cause of Alzheimer’s disease. Isorhynchophylline (IRN, an oxindole alkaloid isolated from Uncaria rhynchophylla, exerts neuroprotective effect against Aβ25–35-induced neurotoxicity in vitro. However, the exact mechanism for its neuroprotective effect is not well understood. The present study aimed to investigate the molecular mechanisms underlying the protective action of IRN against Aβ25–35-induced neurotoxicity in cultured rat pheochromocytoma (PC12 cells. Pretreatment with IRN significantly increased the cell viability, inhibited the release of lactate dehydrogenase and the extent of DNA fragmentation in Aβ25–35-treated cells. IRN treatment was able to enhance the protein levels of phosphorylated Akt (p-Akt and glycogen synthase kinase-3β (p-GSK-3β. Lithium chloride blocked Aβ25–35-induced cellular apoptosis in a similar manner as IRN, suggesting that GSK-3β inhibition was involved in neuroprotective action of IRN. Pretreatment with LY294002 completely abolished the protective effects of IRN. Furthermore, IRN reversed Aβ25–35-induced attenuation in the level of phosphorylated cyclic AMP response element binding protein (p-CREB and the effect of IRN could be blocked by the PI3K inhibitor. These experimental findings unambiguously suggested that the protective effect of IRN against Aβ25–35-induced apoptosis in PC12 cells was associated with the enhancement of p-CREB expression via PI3K/Akt/GSK-3β signaling pathway.

  18. Genetic variants in PI3K/AKT pathway are associated with severe radiation pneumonitis in lung cancer patients treated with radiation therapy.

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    Tang, Yang; Liu, Bo; Li, Jing; Wu, Huanlei; Yang, Ju; Zhou, Xiao; Yi, Mingxiao; Li, Qianxia; Yu, Shiying; Yuan, Xianglin

    2016-01-01

    PI3K/AKT pathway plays important roles in inflammatory and fibrotic diseases while its connection to radiation pneumonitis (RP) is unclear. In this study, we explored the associations of genetic variants in PI3K/AKT pathway with RP in lung cancer patients with radiotherapy. Two hundred and sixty one lung cancer patients with radiotherapy were included in this prospective study (NCT02490319) and genotyped by MassArray and Sanger Sequence methods. By multivariate Cox hazard analysis and multiple testing, GA/GG genotype of AKT2: rs33933140 (HR = 0.272, 95% CI: 0.140-0.530, P = 1.3E-4, Pc = 9.1E-4), and the GT/GG genotype of PI3CA: rs9838117 (HR = 0.132, 95% CI: 0.042-0.416, P = 0.001, Pc = 0.006) were found to be strongly associated with a decreased occurrence of RP ≥ grade 3. And patients with the CT/TT genotype of AKT2: rs11880261 had a notably higher incidence of RP ≥ grade 3 (HR = 2.950, 95% CI: 1.380-6.305, P = 0.005, Pc = 0.025). We concluded that the genetic variants of PI3K/AKT pathway were significantly related to RP of grade ≥ 3 and may thus be predictors of severe RP before radiotherapy, if further validated in larger population.

  19. 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.

  20. Effects of Platycodin D on Proliferation, Apoptosis and PI3K/Akt Signal Pathway of Human Glioma U251 Cells

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    Chong Xu

    2014-12-01

    Full Text Available Effects of platycodin D (PD on the proliferation, apoptosis and PI3K/Akt signaling pathway of human glioma U251 cells were investigated. Glioma U251 cells were treated with PD at final concentrations of 0, 16.3, 40.8, 81.6, 163.2 μM, and inhibition rate, early and late apoptotic rate, apoptotic index, expression of apoptosis-related proteins and phosphorylation of the PI3K/Akt signaling pathway were evaluated. The results showed that compared with the control group, PD could increase the proliferation inhibition rate of U251 cells in a dose- and time -dependent manner; PD could also elevate the early and late apoptotic rate, apoptotic index and the level of pro-apoptotic proteins of glioma U251 cells, such as Bax and cleaved caspase-3, but lower the level of apoptosis inhibitory protein, such as Bcl-2; PD could increase the ratio of G0/G1 phase U251 cells, and lower the proportion of Sphase U251 cells and the ratio of G2/M phase U251 cells; PD could reduce the ratio of p-Akt/Akt. The results indicate that PD can inhibit the proliferation, induce the apoptosis and cause the cell cycle arrest in human glioma U251 cells, which may be related to the inhibition of PD on the activation of PI3K/Akt signaling pathway.

  1. Gemcitabine resistance in breast cancer cells regulated by PI3K/AKT-mediated cellular proliferation exerts negative feedback via the MEK/MAPK and mTOR pathways

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    Yang XL

    2014-06-01

    Full Text Available Xiao Li Yang, Feng Juan Lin, Ya Jie Guo, Zhi Min Shao, Zhou Luo Ou Key Laboratory of Breast Cancer in Shanghai, Breast Cancer Institute, Cancer Hospital, Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, People's Republic of China Abstract: Chemoresistance is a major cause of cancer treatment failure and leads to a reduction in the survival rate of cancer patients. Phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR and mitogen-activated protein kinase (MAPK pathways are aberrantly activated in many malignant tumors, including breast cancer, which may indicate an association with breast cancer chemoresistance. In this study, we generated a chemoresistant human breast cancer cell line, MDA-MB-231/gemcitabine (simplified hereafter as “231/Gem”, from MDA-MB-231 human breast cancer cells. Flow cytometry studies revealed that with the same treatment concentration of gemcitabine, 231/Gem cells displayed more robust resistance to gemcitabine, which was reflected by fewer apoptotic cells and enhanced percentage of S-phase cells. Through the use of inverted microscopy, Cell Counting Kit-8, and Transwell assays, we found that compared with parental 231 cells, 231/Gem cells displayed more morphologic projections, enhanced cell proliferative ability, and improved cell migration and invasion. Mechanistic studies revealed that the PI3K/AKT/mTOR and mitogen-activated protein kinase kinase (MEK/MAPK signaling pathways were activated through elevated expression of phosphorylated (p-extracellular signal-regulated kinase (ERK, p-AKT, mTOR, p-mTOR, p-P70S6K, and reduced expression of p-P38 and LC3-II (the marker of autophagy in 231/Gem in comparison to control cells. However, there was no change in the expression of Cyclin D1 and p-adenosine monophosphate-activated protein kinase (AMPK. In culture, inhibitors of PI3K/AKT and mTOR, but not of MEK/MAPK, could reverse the enhanced proliferative

  2. β-Caryophyllene oxide inhibits growth and induces apoptosis through the suppression of PI3K/AKT/mTOR/S6K1 pathways and ROS-mediated MAPKs activation.

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    Park, Kyung-Ran; Nam, Dongwoo; Yun, Hyung-Mun; Lee, Seok-Geun; Jang, Hyeung-Jin; Sethi, Gautam; Cho, Somi K; Ahn, Kwang Seok

    2011-12-22

    Both PI3K/AKT/mTOR/S6K1 and mitogen activated protein kinase (MAPK) signaling cascades play an important role in cell proliferation, survival, angiogenesis, and metastasis of tumor cells. In the present report, we investigated the effects of β-caryophyllene oxide (CPO), a sesquiterpene isolated from essential oils of medicinal plants such as guava (Psidium guajava), oregano (Origanum vulgare L.), cinnamon (Cinnamomum spp.) clove (Eugenia caryophyllata), and black pepper (Piper nigrum L.) on the PI3K/AKT/mTOR/S6K1 and MAPK activation pathways in human prostate and breast cancer cells. We found that CPO not only inhibited the constitutive activation of PI3K/AKT/mTOR/S6K1 signaling cascade; but also caused the activation of ERK, JNK, and p38 MAPK in tumor cells. CPO induced increased reactive oxygen species (ROS) generation from mitochondria, which is associated with the induction of apoptosis as characterized by positive Annexin V binding and TUNEL staining, loss of mitochondrial membrane potential, release of cytochrome c, activation of caspase-3, and cleavage of PARP. Inhibition of ROS generation by N-acetylcysteine (NAC) significantly prevented CPO-induced apoptosis. Subsequently, CPO also down-regulated the expression of various downstream gene products that mediate cell proliferation (cyclin D1), survival (bcl-2, bcl-xL, survivin, IAP-1, and IAP-2), metastasis (COX-2), angiogenesis (VEGF), and increased the expression of p53 and p21. Interestingly, we also observed that CPO can significantly potentiate the apoptotic effects of various pharmacological PI3K/AKT inhibitors when employed in combination in tumor cells. Overall, these findings suggest that CPO can interfere with multiple signaling cascades involved in tumorigenesis and used as a potential therapeutic candidate for both the prevention and treatment of cancer. PMID:21924548

  3. A genome-wide RNAi screen identifies FOXO4 as a metastasis-suppressor through counteracting PI3K/AKT signal pathway in prostate cancer.

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    Bing Su

    Full Text Available Activation of the PI3K/AKT signal pathway is a known driving force for the progression to castration-recurrent prostate cancer (CR-CaP, which constitutes the major lethal phenotype of CaP. Here, we identify using a genomic shRNA screen the PI3K/AKT-inactivating downstream target, FOXO4, as a potential CaP metastasis suppressor. FOXO4 protein levels inversely correlate with the invasive potential of a panel of human CaP cell lines, with decreased mRNA levels correlating with increased incidence of clinical metastasis. Knockdown (KD of FOXO4 in human LNCaP cells causes increased invasion in vitro and lymph node (LN metastasis in vivo without affecting indices of proliferation or apoptosis. Increased Matrigel invasiveness was found by KD of FOXO1 but not FOXO3. Comparison of differentially expressed genes affected by FOXO4-KD in LNCaP cells in culture, in primary tumors and in LN metastases identified a panel of upregulated genes, including PIP, CAMK2N1, PLA2G16 and PGC, which, if knocked down by siRNA, could decrease the increased invasiveness associated with FOXO4 deficiency. Although only some of these genes encode FOXO promoter binding sites, they are all RUNX2-inducible, and RUNX2 binding to the PIP promoter is increased in FOXO4-KD cells. Indeed, the forced expression of FOXO4 reversed the increased invasiveness of LNCaP/shFOXO4 cells; the forced expression of FOXO4 did not alter RUNX2 protein levels, yet it decreased RUNX2 binding to the PIP promoter, resulting in PIP downregulation. Finally, there was a correlation between FOXO4, but not FOXO1 or FOXO3, downregulation and decreased metastasis-free survival in human CaP patients. Our data strongly suggest that increased PI3K/AKT-mediated metastatic invasiveness in CaP is associated with FOXO4 loss, and that mechanisms to induce FOXO4 re-expression might suppress CaP metastatic aggressiveness.

  4. 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. PMID:25489416

  5. Emodin Protects against Diabetic Cardiomyopathy by Regulating the AKT/GSK-3β Signaling Pathway in the Rat Model

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    Zhiqin Wu

    2014-09-01

    Full Text Available Diabetes mellitus (DM has been recognized as a major health problem. Emodin (Emo has been reported to exhibit protective effects against diabetic nephropathy. However, little has been known about the effect of Emo on diabetic cardiomyopathy (DCM. A type 2 DM model was induced in rats by low dose streptozotocin (STZ combined with high energy intake. We found that Emo-treated groups displayed significantly higher body weight (BW and lower heart weight (HW/BW. Furthermore, Emo could significantly decrease blood glucose, total cholesterol (TG levels, and triglyceride (TC levels in diabetic rats. Moreover, the Emo-treated group showed a marked increase in heart rate (HR and showed lower left ventricular end-diastolic diameter (LVEDD, left ventricular end-systolic diameter (LVESD, left ventricular posterior wall thickness (LWPWT, and interventricular septal diastolic wall thickness (IVSD. Emo induced a significant increase in phosphorylation of Akt and GSK-3β in myocardium. These results suggest that Emo may have great therapeutic potential in the treatment of DCM by Akt/GSK-3β signaling pathway.

  6. Matrine derivative WM130 inhibits hepatocellular carcinoma by suppressing EGFR/ERK/MMP-2 and PTEN/AKT signaling pathways.

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    Qian, Liqiang; Liu, Yan; Xu, Yang; Ji, Weidan; Wu, Qiuye; Liu, Yongjing; Gao, Quangen; Su, Changqing

    2015-11-01

    Matrine, a sophora alkaloid, has been demonstrated to exert antitumor effects on many types of cancer. However, its bioactivity is weak and its potential druggability is low. We modified the structure of matrine and obtained a new matrine derivative, WM130 (C30N4H40SO5F), which exhibited better pharmacological activities than matrine. In this study, we investigated the antitumor activity and the underlying mechanisms of WM130 on hepatocellular carcinoma (HCC) cells in vitro and in vivo, and found that WM130 inhibited the proliferation, invasion, migration and induced apoptosis of HCC cells in a dose-dependent manner. Furthermore, after treatment with WM130, the expressions of p-EGFR, p-ERK, p-AKT, MMP-2 and the ratio of Bcl-2/Bax were significantly down-regulated, whereas the expression of PTEN was increased in HCC cells. Moreover, WM130 inhibited Huh-7 xenograft tumor growth in a dose-dependent manner after intravenous administration. Immunohistochemistry results demonstrated that WM130 treatment resulted in down-regulation of p-EGFR, MMP-2, and Ki67 and up-regulation of PTEN. The findings indicated that WM130 could inhibit cell proliferation, invasion, migration and induced apoptosis in HCC cells by suppressing EGFR/ERK/MMP-2 and PTEN/AKT signaling pathways and may be a novel effective candidate for HCC treatment.

  7. Matrine induces the apoptosis of lung cancer cells through downregulation of inhibitor of apoptosis proteins and the Akt signaling pathway.

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    Niu, Huiyan; Zhang, Yifei; Wu, Baogang; Zhang, Yi; Jiang, Hongfang; He, Ping

    2014-09-01

    Lung cancer is the leading cause of cancer‑related mortality in humans. The prognosis for advanced lung cancer patients is extremely poor. Current standard care is rather ineffective for prolonging patient life while preserving satisfactory quality of life due to adverse side-effects. Matrine extracted from the traditional Chinese herbal plant Sophora flavescens was shown to induce cancer cell death in vitro. The aim of this study was to investigate the effect of matrine on the proliferation and apoptosis of lung cancer cells and the molecular basis of matrine-induced apoptosis. The results showed that matrine inhibited cell proliferation and induced apoptosis in lung cancer A549 and 95D cells in a dose- and time-dependent manner. The apoptotic effects of matrine on lung cancer cells appeared to act via the phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin (PI3K-Akt-mTOR) signaling pathway and downregulation of the expression of the inhibitor of apoptosis protein (IAP) family proteins. Matrine exerts its cancer-killing effect via promoting apoptosis in lung cancer cells and may be a useful adjuvant therapeutic scheme for treating advanced lung cancer patients.

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

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    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.

  9. VEGF Silencing Inhibits Human Osteosarcoma Angiogenesis and Promotes Cell Apoptosis via PI3K/AKT Signaling Pathway.

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    Zhao, Jian; Zhang, Zi-Ru; Zhao, Na; Ma, Bao-An; Fan, Qing-Yu

    2015-11-01

    Vascular endothelial growth factor (VEGF) is one of the most effective angiogenic factors that promote generation of tumor vasculature. VEGF is usually up-regulated in multiple cancers including osteosarcoma and glioma. To further explore the potential molecular mechanism that inhibits tumor growth induced by interference of VEGF expression, we constructed a Lv-shVEGF vector and assessed the efficiency of VEGF silencing and its influence in U2OS cells. The data demonstrate that Lv-shVEGF has high inhibition efficiency on VEGF expression, which inhibits proliferation and promotes apoptosis of U2OS cells in vitro. Our results also indicate that inhibition of VEGF expression suppresses osteosarcoma tumor growth in vivo and reduces osteosarcoma angiogenesis. We also found that the activations of phosphoinositide 3-kinase (PI3K) and protein kinase B (AKT) were considerably reduced after osteosarcoma cells were treated with Lv-shVEGF. Taken together, our data demonstrate that VEGF silencing suppresses cell proliferation, promotes cell apoptosis, and reduces osteosarcoma angiogenesis through inactivation of PI3K/AKT signaling pathway. PMID:27352347

  10. Corynoxine, a natural autophagy enhancer, promotes the clearance of alpha-synuclein via Akt/mTOR pathway.

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    Chen, Lei-Lei; Song, Ju-Xian; Lu, Jia-Hong; Yuan, Zhen-Wei; Liu, Liang-Feng; Durairajan, Siva Sundara Kumar; Li, Min

    2014-06-01

    Parkinson's disease (PD) is the second most common neurodegenerative disorder characterized by the accumulation of protein aggregates (namely Lewy bodies) in dopaminergic neurons in the substantia nigra region of the brain. Alpha-synuclein (α-syn) is the major component of Lewy bodies in PD patients, and impairment of the autophagy-lysosomal system has been linked to its accumulation. In our previous study, we identified an oxindole alkaloid Corynoxine B (Cory B), isolated from Uncaria rhynchophylla (Miq.) Jacks (Gouteng in Chinese), as a Beclin-1-dependent autophagy inducer. In this work, we show that Cory, an enantiomer of Cory B, also induces autophagy in different neuronal cell lines, including N2a and SHSY-5Y cells, which is paralleled with increased lysosomal enzyme cathepsin D. In vivo, Cory promotes the formation of autophagosomes in the fat bodies of Drosophila. By inducing autophagy, Cory promotes the clearance of wild-type and A53T α-syn in inducible PC12 cells. Interestingly, different from its enantiomer Cory B, Cory induces autophagy through the Akt/mTOR pathway as evidenced by the reduction in the levels of phospho-Akt, phospho-mTOR and phospho-p70 S6 Kinase. Collectively, our findings provide experimental evidence for developing Cory as a new autophagy enhancer from Chinese herbal medicine, which may have potential application in the prevention or treatment of PD. PMID:24522518

  11. Involvement of the PI3K/Akt signal pathway in the hypoglycemic effects of tea polysaccharides on diabetic mice.

    Science.gov (United States)

    Li, Shuqin; Chen, Haixia; Wang, Jia; Wang, Xiuming; Hu, Bo; Lv, Funing

    2015-11-01

    In order to investigate the hypoglycemic effects and potential mechanism of tea polysaccharides (TPS) on diabetes, type 2 diabetes mellitus (T2DM) mice were established and treated with TPS. Results showed that TPS treatment could result in the increase of body weight and the decrease of blood glucose in the diabetic mice. The contents of total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-c) were decreased significantly (p<0.05) while the contents of triglyceride (TG) and (high-density lipoprotein cholesterol) HDL-c were almost restored to the normal levels. TPS possessed the efficacy of insulin resistance alleviation and exerted obvious cytoprotective action. The enzyme activities of superoxide dismutase (SOD) and glutathione peroxidase (GPX) were notably improved in both liver and kidney tissues (p<0.05) after the treatment of TPS. Furthermore, the expressions of PI3Kp85/p-Akt/GLUT4 were upregulated by TPS, which indicated the involvement of the PI3K/Akt signal pathway in the hypoglycemic mechanism of TPS. Results suggested that TPS could ameliorate the T2MD and might be a promising candidate functional food or medicine for T2DM treatment.

  12. Activated platelets from diabetic rats cause endothelial dysfunction by decreasing Akt/endothelial NO synthase signaling pathway.

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    Keiko Ishida

    Full Text Available Diabetes is associated with endothelial dysfunction and platelet activation, both of which may contribute to increased cardiovascular risk. The purpose of this study was to characterize circulating platelets in diabetes and clarify their effects on endothelial function. Male Wistar rats were injected with streptozotocin (STZ to induce diabetes. Each experiment was performed by incubating carotid arterial rings with platelets (1.65×10(7 cells/mL; 30 min isolated from STZ or control rats. Thereafter, the vascular function was characterized in isolated carotid arterial rings in organ bath chambers, and each expression and activation of enzymes involved in nitric oxide and oxidative stress levels were analyzed. Endothelium-dependent relaxation induced by acetylcholine was significantly attenuated in carotid arteries treated with platelets isolated from STZ rats. Similarly, treatment with platelets isolated from STZ rats significantly reduced ACh-induced Akt/endothelial NO synthase signaling/NO production and enhanced TXB2 (metabolite of TXA2, while CD61 (platelet marker and CD62P (activated platelet marker were increased in carotid arteries treated with platelets isolated from STZ rats. Furthermore, the platelets isolated from STZ rats decreased total eNOS protein and eNOS dimerization, and increased oxidative stress. These data provide direct evidence that circulating platelets isolated from diabetic rats cause dysfunction of the endothelium by decreasing NO production (via Akt/endothelial NO synthase signaling pathway and increasing TXA2. Moreover, activated platelets disrupt the carotid artery by increasing oxidative stress.

  13. Visual detection of Akt mRNA in living cell using gold nanoparticle beacon

    Science.gov (United States)

    Ma, Yi; Tian, Caiping; Li, Siwen; Wang, Zhaohui; Gu, Yueqing

    2014-09-01

    PI3K-Akt signaling pathway plays the key role in cell apoptosis and survival, and the components of PI3K /Akt signaling pathway are often abnormally expressed in human tumors. Therefore, determination of the Akt (protein kinase B, PKB) messenger ribonucleic acid (mRNA) expression is significantly important in understanding the mechanism of tumor progression. In this study, we designed a special hairpin deoxyribonucleic acid (DNA) functionalized with gold nanoparticles and fluorescein isothiocyanate(FITC) as a beacon for detecting human Akt mRNA. Spectrofluorometer was used to detect the fluorescence quenching and recovery of the beacons, and laser confocal scanning microscopy was adopted to image Akt mRNA in cells. The results showed that this beacon could sensitively and quantitatively measure the Akt mRNA in living cells . This strategy is potentially useful for the cellular imaging of RNA or protein expression in living cells.

  14. Arginine ADP-ribosyltransferase 1 promotes angiogenesis in colorectal cancer via the PI3K/Akt pathway.

    Science.gov (United States)

    Yang, Lian; Xiao, Ming; Li, Xian; Tang, Yi; Wang, Ya-Lan

    2016-03-01

    Arginine adenosine diphosphate (ADP)-ribosyl-transferase 1 (ART1) is known to play an important role in many physiological and pathological processes. Previous studies have demonstrated that ART1 promotes proliferation, invasion and metastasis in colon carcinoma. However, it was unclear whether ART1 is involved in angiogenesis in cases of colorectal cancer (CRC). In the present study, lentiviral vector‑mediated ART1‑cDNA or ART1-shRNA were transfected into LoVo cells, and the LoVo cells transfected with ART1-cDNA or ART1-shRNA were co-cultured with human umbilical vein endothelial cells (HUVECs) to determine the influence of ART1 on HUVECs. The proliferation, migration and angiogenesis of HUVECs were monitored using a cell counting kit-8 assay, a Transwell migration assay and immunohistochemical analysis in intrasplenic allograft tumors, respectively. Hypoxia‑inducible factor 1-α (HIF-1α), total (t-)Akt, phosphorylated (p-)Akt, vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) expression levels were detected via western blot analysis. Our results revealed that HUVECs which were co-cultured with ART1-cDNA LoVo cells showed higher proliferation, migration and angiogenic abilities, but a reduction was noted in those cultured with ART1-shRNA LoVo cells; p-Akt, HIF-1α, VEGF and bFGF expression was increased in HUVECs cultured with ART1‑cDNA-transfected LoVo cells, but reduced in ART1-shRNA-transfected LoVo cells. In a mouse xenograft model, we noted that the tumor microvessel density (MVD) was significantly increased in intrasplenic transplanted ART1‑cDNA CT26 tumors but decreased in intrasplenic transplanted ART1‑shRNA tumors. These data suggest that ART1 promoted the expression of HIF-1α via the Akt pathway in tumor cells. It also upregulated VEGF and bFGF and enhanced angiogenesis in HUVECs. Thus, we suggest that ART1 plays an important role in the invasion of CRC cells and the metastasis of CRC.

  15. Ghrelin inhibits the apoptosis of MC3T3-E1 cells through ERK and AKT signaling pathway

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    Liang, Qiu-Hua; Liu, Yuan; Wu, Shan-Shan; Cui, Rong-Rong; Yuan, Ling-Qing, E-mail: allenylq@hotmail.com; Liao, Er-Yuan, E-mail: eyliao@21cn.com

    2013-11-01

    Ghrelin is a 28-amino-acid peptide that acts as a natural endogenous ligand of the growth hormone secretagogue receptor (GHSR) and strongly stimulates the release of growth hormone from the hypothalamus–pituitary axis. Previous studies have identified the important physiological effects of ghrelin on bone metabolism, such as regulating proliferation and differentiation of osteoblasts, independent of GH/IGF-1 axis. However, research on effects and mechanisms of ghrelin on osteoblast apoptosis is still rare. In this study, we identified expression of GHSR in MC3T3-E1 cells and determined the effects of ghrelin on the apoptosis of osteoblastic MC3T3-E1 cells and the mechanism involved. Our data demonstrated that ghrelin inhibited the apoptosis of osteoblastic MC3T3-E1 cells induced by serum deprivation, as determined by terminal deoxynucleotidyl transferase-mediated deoxyribonucleotide triphosphate nick end-labeling (TUNEL) and ELISA assays. Moreover, ghrelin upregulated Bcl-2 expression and downregulated Bax expression in a dose-dependent manner. Our study also showed decreased activated caspase-3 activity under the treatment of ghrelin. Further study suggested that ghrelin stimulated the phosphorylation of ERK and AKT. Pretreatment of cells with the ERK inhibitor PD98059, PI3K inhibitor LY294002, and GHSR-siRNA blocked the ghrelin-induced activation of ERK and AKT, respectively; however, ghrelin did not stimulate the phosphorylation of p38 or JNK. PD90859, LY294002 and GHSR-siRNA attenuated the anti-apoptosis effect of ghrelin in MC3T3-E1 cells. In conclusion, ghrelin inhibits the apoptosis of osteoblastic MC3T3-E1 cells induced by serum deprivation, which may be mediated by activating the GHSR/ERK and GHSR/PI3K/AKT signaling pathways. - Highlights: • We explored the effects of ghrelin on serum deprivation-induced MC3T3-E1 cells apoptosis. • Both ELISA and TUNEL were used to detect the apoptosis. • The receptor of ghrelin, GHSR, was expressed in MC3T3-E1

  16. Mitochondrial Akt Regulation of Hypoxic Tumor Reprogramming.

    Science.gov (United States)

    Chae, Young Chan; Vaira, Valentina; Caino, M Cecilia; Tang, Hsin-Yao; Seo, Jae Ho; Kossenkov, Andrew V; Ottobrini, Luisa; Martelli, Cristina; Lucignani, Giovanni; Bertolini, Irene; Locatelli, Marco; Bryant, Kelly G; Ghosh, Jagadish C; Lisanti, Sofia; Ku, Bonsu; Bosari, Silvano; Languino, Lucia R; Speicher, David W; Altieri, Dario C

    2016-08-01

    Hypoxia is a universal driver of aggressive tumor behavior, but the underlying mechanisms are not completely understood. Using a phosphoproteomics screen, we now show that active Akt accumulates in the mitochondria during hypoxia and phosphorylates pyruvate dehydrogenase kinase 1 (PDK1) on Thr346 to inactivate the pyruvate dehydrogenase complex. In turn, this pathway switches tumor metabolism toward glycolysis, antagonizes apoptosis and autophagy, dampens oxidative stress, and maintains tumor cell proliferation in the face of severe hypoxia. Mitochondrial Akt-PDK1 signaling correlates with unfavorable prognostic markers and shorter survival in glioma patients and may provide an "actionable" therapeutic target in cancer. PMID:27505672

  17. Adenosine triphosphate-sensitive potassium channel opener protects PC12 cells against hypoxia-induced apoptosis through PI3K/Akt and Bcl-2 signaling pathways

    Institute of Scientific and Technical Information of China (English)

    Hong Zhang; Chunhong Jia; Danyang Zhao; Yang Lu; Runling Wang; Jia Li

    2010-01-01

    Although previous studies have shown the neuroprotective effects of the adenosine triphosphate (ATP)-sensitive potassium (KATP) channel opener against ischemic neuronal damage, little is known about the mechanisms involved. Phosphatidylinositol-3 kinase (PI3K)/v-akt murine thy-moma viral oncogene homolog (Akt) and Bcl-2 are thought to be important factors that mediate neuroprotection. The present study investigated the effects of KATP openers on hypoxia-induced PC12 cell apoptosis, as well as mRNA and protein expression of Akt and Bcl-2. Results demon-strated that pretreatment of PC12 cells with pinacidil, a KATP opener, resulted in decreased PC12 cell apoptosis following hypoxia, as detected by Annexin-V fluorescein isothiocyanate/ propidium iodide double staining flow cytometry. In addition, mRNA and protein expression of phosphorylated Akt (p-Akt) and Bcl-2 increased, as detected by immunofluorescence, Western blot analysis, and reverse-transcription polymerase chain reaction. The protective effect of this preconditioning was attenuated by glipizide, a selective KATP blocker. These results demonstrate for the first time that the protective mechanisms of KATP openers on PC12 cell apoptosis following hypoxia could result from activation of the PI3K/Akt signaling pathway, which further activates expression of the downstream Bcl-2 gene.

  18. Matrine induces apoptosis in human acute myeloid leukemia cells via the mitochondrial pathway and Akt inactivation.

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    Shenghui Zhang

    Full Text Available Acute myeloid leukemia (AML is a hematological malignancy characterized by a rapid increase in the number of immature myeloid cells in bone marrow. Despite recent advances in the treatment, AML remains an incurable disease. Matrine, a major component extracted from Sophora flavescens Ait, has been demonstrated to exert anticancer effects on various cancer cell lines. However, the effects of matrine on AML remain largely unknown. Here we investigated its anticancer effects and underlying mechanisms on human AML cells in vitro and in vivo. The results showed that matrine inhibited cell viability and induced cell apoptosis in AML cell lines as well as primary AML cells from patients with AML in a dose- and time-dependent manner. Matrine induced apoptosis by collapsing the mitochondrial membrane potential, inducing cytochrome c release from mitochondria, reducing the ratio of Bcl-2/Bax, increasing activation of caspase-3, and decreasing the levels of p-Akt and p-ERK1/2. The apoptotic effects of matrine on AML cells were partially blocked by a caspase-3 inhibitor Z-DEVD-FMK and a PI3K/Akt activator IGF-1, respectively. Matrine potently inhibited in vivo tumor growth following subcutaneous inoculation of HL-60 cells in SCID mice. These findings indicate that matrine can inhibit cell proliferation and induce apoptosis of AML cells and may be a novel effective candidate as chemotherapeutic agent against AML.

  19. Comparative mRNA Expression of eEF1A Isoforms and a PI3K/Akt/mTOR Pathway in a Cellular Model of Parkinson’s Disease

    Directory of Open Access Journals (Sweden)

    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.

  20. Halofuginone inhibits Smad3 phosphorylation via the PI3K/Akt and MAPK/ERK pathways in muscle cells: Effect on myotube fusion

    Energy Technology Data Exchange (ETDEWEB)

    Roffe, Suzy [Department of Animal Sciences, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100 (Israel); Hagai, Yosey [Department of Animal Sciences, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100 (Israel); Institute of Animal Sciences, Volcani Center, Bet Dagan 50250 (Israel); Pines, Mark [Institute of Animal Sciences, Volcani Center, Bet Dagan 50250 (Israel); Halevy, Orna, E-mail: halevyo@agri.huji.ac.il [Department of Animal Sciences, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100 (Israel)

    2010-04-01

    Halofuginone, a novel inhibitor of Smad3 phosphorylation, has been shown to inhibit muscle fibrosis and to improve cardiac and skeletal muscle functions in the mdx mouse model of Duchenne muscular dystrophy. Here, we demonstrate that halofuginone promotes the phosphorylation of Akt and mitogen-activated protein kinase (MAPK) family members in a C2 muscle cell line and in primary myoblasts derived from wild-type and mdx mice diaphragms. Halofuginone enhanced the association of phosphorylated Akt and MAPK/extracellular signal-regulated protein kinase (ERK) with the non-phosphorylated form of Smad3, accompanied by a reduction in Smad3 phosphorylation levels. This reduction was reversed by inhibitors of the phosphoinositide 3'-kinase/Akt (PI3K/Akt) and MAPK/ERK pathways, suggesting their specific role in mediating halofuginone's inhibitory effect on Smad3 phosphorylation. Halofuginone enhanced Akt, MAPK/ERK and p38 MAPK phosphorylation and inhibited Smad3 phosphorylation in myotubes, all of which are crucial for myotube fusion. In addition, halofuginone increased the association Akt and MAPK/ERK with Smad3. As a consequence, halofuginone promoted myotube fusion, as reflected by an increased percentage of C2 and mdx myotubes containing high numbers of nuclei, and this was reversed by specific inhibitors of the PI3K and MAPK/ERK pathways. Together, the data suggest a role, either direct or via inhibition of Smad3 phosphorylation, for Akt or MAPK/ERK in halofuginone-enhanced myotube fusion, a feature which is crucial to improving muscle function in muscular dystrophies.

  1. Extrapancreatic roles of glimepiride on osteoblasts from rat manibular bone in vitro: Regulation of cytodifferentiation through PI3-kinases/Akt signalling pathway.

    Science.gov (United States)

    Ma, Pan; Xiong, Wei; Liu, Hongchen; Ma, Junli; Gu, Bin; Wu, Xia

    2011-04-01

    Glimepiride, a third-generation sulfonylurea, has also been reported to have extrapancreatic functions including activation of PI3-kinase (PI3K) and Akt in rat adipocytes, skeletal muscle and endothelial cells. It is tempting to speculate that glimepiride would improve bone-implant contact in diabetic patients by mediating the activity of GLUT1 and 3 via the PI3K/Akt pathway. In this study, we investigated the effects of glimepiride on rat mandible osteoblasts cultured under two different levels of glucose. Cell proliferation was determined by the MTT assay. The supernatant was used to measure alkaline phosphatase (ALP) activity. Glucose uptake was determined by measuring the rate of 2-deoxy-d-glucose (2-DG) uptake. Western blotting was performed used to determine collagen I and PI3K/Akt expression. RT-PCR was performed used to determine osteocalcin (OCN) mRNA expression. We found that hyperglycemia down-regulated proliferation, ALP activity, OCN mRNA and GLUT3 protein expression in rat osteoblasts, and upregulated collagen I and GLUT1 protein expressions. Glimepiride enhanced the proliferation, ALP activity and OCN mRNA levels, and upregulated collagen I and GLUT1 and 3 protein expressions of rat osteoblasts at two different glucose concentrations. This study also provides the first evidence that glimepiride stimulates the phosphorylation of PI3K/Akt in osteoblasts and ameliorated the damage caused by high concentrations of glucose through the PI3K/Akt pathway. PMID:21055727

  2. HspB8 mediates neuroprotection against OGD/R in N2A cells through the phosphoinositide 3-kinase/Akt pathway.

    Science.gov (United States)

    Hu, Zhiping; Yang, Binbin; Mo, Xiaoye; Zhou, Fangfang

    2016-08-01

    In a previous study, we found that Heat shock protein B8 (HspB8) overexpression could prevent the apoptosis and reduced cell viability induced by OGD/R and showed that the neuroprotective effect of HspB8 was mediated by inhibition of the mitochondrial apoptotic pathway. In recent study, HspB8 has been shown to protect the heart against ischemia/reperfusion (I/R) injury via activation of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway. However, whether this protective effect applied to brain I/R injury remained unexplored. To further test the mechanism of HspB8's effects in brain, we used oxygen-glucose deprivation followed by reperfusion (OGD/R), an in vitro model of ischemia to examine the involvement of PI3K/Akt signaling by treating mouse neuroblastoma cells (N2A cells) (untransfected or transfected with an HspB8 expression vector) with the PI3K inhibitor LY294002 before OGD/R. Our results revealed that the apoptosis-suppressing effect of HspB8 was mediated by the PI3K/Akt pathway. Therefore, HspB8 protected the N2A cells against OGD/R insult, possibly by activating the PI3K/Akt signaling pathway. PMID:27178361

  3. Campylobacter jejuni induces an anti-inflammatory response in human intestinal epithelial cells through activation of phosphatidylinositol 3-kinase/Akt pathway

    DEFF Research Database (Denmark)

    Li, Yiping; Vegge, Christina S.; Brøndsted, Lone;

    2011-01-01

    for cytolethal distending toxin (CDT) deficient mutants. Moreover, we demonstrated that heat-killed bacteria were able to induce IL-8 and IL-10 expression to a lower level than live bacteria. We therefore conclude that C. jejuni activate a PI3K/Akt-dependent anti-inflammatory pathway in human intestinal...

  4. Escitalopram attenuates β-amyloid-induced tau hyperphosphorylation in primary hippocampal neurons through the 5-HT1A receptor mediated Akt/GSK-3β pathway.

    Science.gov (United States)

    Wang, Yan-Juan; Ren, Qing-Guo; Gong, Wei-Gang; Wu, Di; Tang, Xiang; Li, Xiao-Li; Wu, Fang-Fang; Bai, Feng; Xu, Lin; Zhang, Zhi-Jun

    2016-03-22

    Tau hyperphosphorylation is an important pathological feature of Alzheimer's disease (AD). To investigate whether escitalopram could inhibit amyloid-β (Aβ)-induced tau hyperphosphorylation and the underlying mechanisms, we treated the rat primary hippocampal neurons with Aβ1-42 and examined the effect of escitalopram on tau hyperphosphorylation. Results showed that escitalopram decreased Aβ1-42-induced tau hyperphosphorylation. In addition, escitalopram activated the Akt/GSK-3β pathway, and the PI3K inhibitor LY294002 blocked the attenuation of tau hyperphosphorylation induced by escitalopram. Moreover, the 5-HT1A receptor agonist 8-OH-DPAT also activated the Akt/GSK-3β pathway and decreased Aβ1-42-induced tau hyperphosphorylation. Furthermore, the 5-HT1A receptor antagonist WAY-100635 blocked the activation of Akt/GSK-3β pathway and the attenuation of tau hyperphosphorylation induced by escitalopram. Finally, escitalopram improved Aβ1-42 induced impairment of neurite outgrowth and spine density, and reversed Aβ1-42 induced reduction of synaptic proteins. Our results demonstrated that escitalopram attenuated Aβ1-42-induced tau hyperphosphorylation in primary hippocampal neurons through the 5-HT1A receptor mediated Akt/GSK-3β pathway. PMID:26950279

  5. Puerarin protects rat kidney from lead-induced apoptosis by modulating the PI3K/Akt/eNOS pathway

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chan-Min, E-mail: lcm9009@126.com [School of Life Science, Xuzhou Normal University, No.101, Shanghai Road, Tangshan New Area, Xuzhou City 221116, Xuzhou City, Jiangsu Province (China); Ma, Jie-Qiong [School of Chemical Engineering, China University of Mining and Technology, Xuzhou 221008, Xuzhou City, Jiangsu Province (China); Sun, Yun-Zhi [School of Life Science, Xuzhou Normal University, No.101, Shanghai Road, Tangshan New Area, Xuzhou City 221116, Xuzhou City, Jiangsu Province (China)

    2012-02-01

    Puerarin (PU), a natural flavonoid, has been reported to have many benefits and medicinal properties. However, its protective effects against lead (Pb) induced injury in kidney have not been clarified. The aim of the present study was to investigate the effects of puerarin on renal oxidative stress and apoptosis in rats exposed to Pb. Wistar rats were exposed to lead acetate in the drinking water (500 mg Pb/l) with or without puerarin co-administration (100, 200, 300 and 400 mg PU/kg intragastrically once daily) for 75 days. Our data showed that puerarin significantly prevented Pb-induced nephrotoxicity in a dose-dependent manner, indicated by both diagnostic indicators of kidney damage (serum urea, uric acid and creatinine) and histopathological analysis. Moreover, Pb-induced profound elevation of reactive oxygen species (ROS) production and oxidative stress, as evidenced by increasing of lipid peroxidation level and depleting of intracellular reduced glutathione (GSH) level in kidney, were suppressed by treatment with puerarin. Furthermore, TUNEL assay showed that Pb-induced apoptosis in rat kidney was significantly inhibited by puerarin. In exploring the underlying mechanisms of puerarin action, we found that activities of caspase-3 were markedly inhibited by the treatment of puerarin in the kidney of Pb-treated rats. Puerarin increased phosphorylated Akt, phosphorylated eNOS and NO levels in kidney, which in turn inactivated pro-apoptotic signaling events including inhibition of mitochondria cytochrome c release and restoration of the balance between pro- and anti-apoptotic Bcl-2 proteins in kidney of Pb-treated rats. In conclusion, these results suggested that the inhibition of Pb-induced apoptosis by puerarin is due at least in part to its antioxidant activity and its ability to modulate the PI3K/Akt/eNOS signaling pathway. Highlights: ► Puerarin prevented lead-induced nephrototoxicity. ► Puerarin reduced lead-induced increase in ROS and TBARS production

  6. AKT-Foxo3 a信号通路调控小鼠MMP-20基因表达的研究%AKT-Foxo3 a signaling pathway in regulation of MMP-20 gene expression in mouse ameloblasts

    Institute of Scientific and Technical Information of China (English)

    梁广智; 王云虹; 刘媛媛; 慈浩粟; 荣丽; 韩晓谦; 孙轶群; 高玉光

    2014-01-01

    AIM:To investigate the role of AKT-Foxo3a signaling pathway in matrix metalloproteinase-20 (MMP-20)gene expression in mouse ameloblasts.METHODS:AKT-Foxo3a and MMP-20 expression in mouse ameloblasts were examined by immunohistochemistry.Effects of AKT-Foxo3a signaling pathway on MMP-20 promoter were investigated by real-time quantitative RT-PCR and dual luciferase reporter gene assay system.RESULTS:Im-munohistochemical staining results showed that AKT and phosphorylated Foxo3a (P-Foxo3a)were both strongly ex-pressed in the nuclei of secretory ameloblasts.By RT-PCR,it was found that AKT inhibitor reduced the Foxo3a in-duced MMP-20 gene expression (P<0.05).Dual luciferase assay showed that AKT inhibitor decreased MMP-20 pro-moter activity (P<0.05).CONCLUSION:Foxo3a regulates MMP-20 gene expression through AKT-Foxo3a signa-ling pathway in mouse ameloblasts.%目的:本研究旨在探讨AKT-Foxo3a信号通路在基质金属蛋白酶-20(matrix metalloprotein-ase-20,MMP-20)基因表达中的作用。方法:分别通过免疫组化技术、实时定量RT-PCR技术以及双荧光素酶报告基因检测系统分析AKT-Foxo3 a信号通路对MMP-20启动子转录活性的影响。结果:免疫组化染色结果显示,AKT及磷酸化Foxo3 a(P-Foxo3 a)均在分泌期成釉细胞核中呈阳性表达;RT-PCR检测结果显示,AKT阻断剂可显著抑制Foxo3a 诱导的MMP-20基因的表达(P"0.05);双荧光素酶分析结果显示,AKT阻断剂亦可显著抑制Foxo3a调控 MMP-20基因启动子的转录活性(P "0.05)。结论:转录因子 Foxo3a 可能通过AKT-Foxo3 a信号通路调控MMP-20基因的表达,从而参与釉质发育过程。

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

    Science.gov (United States)

    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.

  8. Glimepiride Promotes Osteogenic Differentiation in Rat Osteoblasts via the PI3K/Akt/eNOS Pathway in a High Glucose Microenvironment

    OpenAIRE

    Pan Ma; Bin Gu; Wei Xiong; Baosheng Tan; Wei Geng; Jun Li; Hongchen Liu

    2014-01-01

    Our previous studies demonstrated that glimepiride enhanced the proliferation and differentiation of osteoblasts and led to activation of the PI3K/Akt pathway. Recent genetic evidence shows that endothelial nitric oxide synthase (eNOS) plays an important role in bone homeostasis. In this study, we further elucidated the roles of eNOS, PI3K and Akt in bone formation by osteoblasts induced by glimepiride in a high glucose microenvironment. We demonstrated that high glucose (16.5 mM) inhibits th...

  9. EPHA2通过增强Akt/mTOR信号通路促进SGC-7901细胞的增殖%EPHA2 promotes SGC-7901 cell proliferation through enhancing Akt/mTOR signaling pathway

    Institute of Scientific and Technical Information of China (English)

    李国栋; 王洋洋; 刘玉河; 李湘奇

    2016-01-01

    Background and purpose:EPHA2 has been reported to enhance the proliferation of gastric cancer cells through promoting CyclinD1 expression and cell cycle progression. However, the underlying mechanism that EPHA2 promotes CyclinD1 expression and cell cycle progression is still poorly understood. Akt/mTOR signaling pathway has been reported to enhance the proliferation of gastric cancer cells by promoting CyclinD1 expression and cell cycle progression, and some studies have shown that EPHA2 can activate Akt/mTOR signaling pathway. Based on this, this study investigated whether EPHA2 promoted gastric cancer SGC-7901 cell proliferation through enhancing Akt/mTOR signaling pathway.Methods:Western blot was used to determine the effect of EPHA2 overexpression or knockdown on the phosphorylation of Akt and mTOR in SGC-7901 cells. SGC-7901-NC infected with control lentivi-rus and SGC-7901-EPHA2 cells with EPHA2 overexpression were treated with DMSO, MK2206 (an Akt inhibitor) and RAD001 (a mTOR inhibitor) for different time periods, respectively. Cell proliferation was detected using the CCK8 assay. Cell cycle was detected using lfow cytometry, and the expression of CyclinD1 was determined by Western blot. Results:Overexpression of EPHA2 enhanced Akt/mTOR signaling pathway in SGC-7901 cells, and silencing EPHA2 in SGC-7901 cells inhibited Akt/mTOR signaling pathway. MK2206 and RAD001 antagonized the promoting effect of EPHA2 on the proliferation, S-phase and CyclinD1 expression of SGC-7901 cells, respectively.Conclusion:EPHA2 promotes SGC-7901 cell proliferation through enhancing Akt/mTOR signaling pathway. Akt inhibitor or mTOR inhibi-tor could be an effective treatment strategy for gastric cancer patients overexpressing EPHA2.%背景与目的:EPHA2能够促进胃癌细胞中Cyclin D1的表达及胃癌细胞的细胞周期进程,从而增强胃癌细胞的增殖能力,但EPHA2调控胃癌细胞中Cyclin D1的表达及胃癌细胞的细胞周期进程的分子机制依

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

    Science.gov (United States)

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

    2016-04-01

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

  11. Erythropoietin protects cardiomyocytes from cell death during hypoxia/reperfusion injury through activation of survival signaling pathways.

    Directory of Open Access Journals (Sweden)

    Asiya A Parvin

    Full Text Available Hypoxia/Reoxygenation (H/R cardiac injury is of great importance in understanding Myocardial Infarctions, which affect a major part of the working population causing debilitating side effects and often-premature mortality. H/R injury primarily consists of apoptotic and necrotic death of cardiomyocytes due to a compromise in the integrity of the mitochondrial membrane. Major factors associated in the deregulation of the membrane include fluctuating reactive oxygen species (ROS, deregulation of mitochondrial permeability transport pore (MPTP, uncontrolled calcium (Ca2+ fluxes, and abnormal caspase-3 activity. Erythropoietin (EPO is strongly inferred to be cardioprotective and acts by inhibiting the above-mentioned processes. Surprisingly, the underlying mechanism of EPO's action and H/R injury is yet to be fully investigated and elucidated. This study examined whether EPO maintains Ca2+ homeostasis and the mitochondrial membrane potential (ΔΨm in cardiomyocytes when subjected to H/R injury and further explored the underlying mechanisms involved. H9C2 cells were exposed to different concentrations of EPO post-H/R, and 20 U/ml EPO was found to significantly increase cell viability by inhibiting the intracellular production of ROS and caspase-3 activity. The protective effect of EPO was abolished when H/R-induced H9C2 cells were treated with Wortmannin, an inhibitor of Akt, suggesting the mechanism of action through the activation Akt, a major survival pathway.

  12. 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.

  13. CD44v6 regulates growth of brain tumor stem cells partially through the AKT-mediated pathway.

    Directory of Open Access Journals (Sweden)

    Mayumi Jijiwa

    Full Text Available Identification of stem cell-like brain tumor cells (brain tumor stem-like cells; BTSC has gained substantial attention by scientists and physicians. However, the mechanism of tumor initiation and proliferation is still poorly understood. CD44 is a cell surface protein linked to tumorigenesis in various cancers. In particular, one of its variant isoforms, CD44v6, is associated with several cancer types. To date its expression and function in BTSC is yet to be identified. Here, we demonstrate the presence and function of the variant form 6 of CD44 (CD44v6 in BTSC of a subset of glioblastoma multiforme (GBM. Patients with CD44(high GBM exhibited significantly poorer prognoses. Among various variant forms, CD44v6 was the only isoform that was detected in BTSC and its knockdown inhibited in vitro growth of BTSC from CD44(high GBM but not from CD44(low GBM. In contrast, this siRNA-mediated growth inhibition was not apparent in the matched GBM sample that does not possess stem-like properties. Stimulation with a CD44v6 ligand, osteopontin (OPN, increased expression of phosphorylated AKT in CD44(high GBM, but not in CD44(low GBM. Lastly, in a mouse spontaneous intracranial tumor model, CD44v6 was abundantly expressed by tumor precursors, in contrast to no detectable CD44v6 expression in normal neural precursors. Furthermore, overexpression of mouse CD44v6 or OPN, but not its dominant negative form, resulted in enhanced growth of the mouse tumor stem-like cells in vitro. Collectively, these data indicate that a subset of GBM expresses high CD44 in BTSC, and its growth may depend on CD44v6/AKT pathway.

  14. Expansion and long-term culture of human spermatogonial stem cells via the activation of SMAD3 and AKT pathways

    Science.gov (United States)

    Guo, Ying; Liu, Linhong; Sun, Min; Hai, Yanan; Li, Zheng

    2015-01-01

    Spermatogonial stem cells (SSCs) can differentiate into spermatids, reflecting that they could be used in reproductive medicine for treating male infertility. SSCs are able to become embryonic stem-like cells with the potentials of differentiating into numerous cell types of the three germ layers and they can transdifferentiate to mature and functional cells of other lineages, highlighting significant applications of human SSCs for treating human diseases. However, human SSCs are very rare and a long-term culture system of human SSCs has not yet established. This aim of study was to isolate, identify and culture human SSCs for a long period. We isolated GPR125-positive spermatogonia with high purity and viability from adult human testicular tissues utilizing the two-step enzymatic digestion and magnetic-activated cell sorting with antibody against GPR125. These freshly isolated cells expressed a number of markers for SSCs, including GPR125, PLZF, GFRA1, RET, THY1, UCHL1 and MAGEA4, but not the hallmarks for spermatocytes and spermatozoa, e.g. SYCP1, SYCP3, PRM1, and TNP1. The isolated human SSCs could be cultured for two months with a significant increase of cell number with the defined medium containing growth factors and hydrogel. Notably, the expression of numerous SSC markers was maintained during the cultivation of human SSCs. Furthermore, SMAD3 and AKT phosphorylation was enhanced during the culture of human SSCs. Collectively, these results suggest that human SSCs can be cultivated for a long period and expanded whilst retaining an undifferentiated status via the activation of SMAD3 and AKT pathways. This study could provide sufficient cells of SSCs for their basic research and clinic applications in reproductive and regenerative medicine. PMID:26088866

  15. miR-451a is underexpressed and targets AKT/mTOR pathway in papillary thyroid carcinoma.

    Science.gov (United States)

    Minna, Emanuela; Romeo, Paola; Dugo, Matteo; De Cecco, Loris; Todoerti, Katia; Pilotti, Silvana; Perrone, Federica; Seregni, Ettore; Agnelli, Luca; Neri, Antonino; Greco, Angela; Borrello, Maria Grazia

    2016-03-15

    Papillary Thyroid Carcinoma (PTC) is the most frequent thyroid cancer. Although several PTC-specific miRNA profiles have been reported, only few upregulated miRNAs are broadly recognized, while less consistent data are available about downregulated miRNAs. In this study we investigated miRNA deregulation in PTC by miRNA microarray, analysis of a public dataset from The Cancer Genome Atlas (TCGA), literature review and meta-analysis based on a univocal miRNA identifier derived from miRBase v21. A list of 18 miRNAs differentially expressed between PTC and normal thyroid was identified and validated in the TCGA dataset. Furthermore, we compared our signature with miRNA profiles derived from 15 studies selected from literature. Then, to select possibly functionally relevant miRNA, we integrated our miRNA signature with those from two in vitro cell models based on the PTC-driving oncogene RET/PTC1. Through this strategy, we identified commonly deregulated miRNAs, including miR-451a, which emerged also by our meta-analysis as the most frequently reported downregulated miRNA. We showed that lower expression of miR-451a correlates with aggressive clinical-pathological features of PTC as tall cell variant, advanced stage and extrathyroid extension. In addition, we demonstrated that ectopic expression of miR-451a impairs proliferation and migration of two PTC-derived cell lines, reduces the protein levels of its recognized targets MIF, c-MYC and AKT1 and attenuates AKT/mTOR pathway activation.Overall, our study provide both an updated overview of miRNA deregulation in PTC and the first functional evidence that miR-451a exerts tumor suppressor functions in this neoplasia. PMID:26871295

  16. 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.

  17. Oridonin induces apoptosis via PI3K/Akt pathway in cervical carcinoma HeLa cell line

    Institute of Scientific and Technical Information of China (English)

    Hong-zhen HU; Yue-bo YANG; Xiang-dong XU; Hong-wei SHEN; Yi-min SHU; Zi REN; Xiao-mao LI; Hui-ming SHEN; Hai-tao ZENG

    2007-01-01

    Aim:To investigate the apoptosis-inducing effect of oridonin,a diterpenoid isolated from Rabdosia rubescens,in the human cervical carcinoma HeLa cell line.Methods:A morphological analysis,nuclear condensation,and fragmentation of chromatin were monitored using Hoechst 33342 staining. Cell viability was assessed using the 3-(4,5-dimethylthiazol-(2)-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Cell apoptosis and the apoptosis-related activation in the HeLa cell line were evaluated by flow cytometry and Western blotting. Results:Oridonin suppressed the proliferation of the HeLa cell line in a dose- and time-dependent fashion. Oridonin treatment downregulated the activation of protein kinase B (Akt),the expression of forkhead box class O (FOXO) transcription factor,and glycogen synthase kinase 3 (GSK3). Oridonin also induced the release of cytochrome c accompanied by the activation of caspase-3 and poly-adenosine diphosphate-ribose polymerase cleavage. In addition,Z-D(OMe)-E(OMe)-V-D(OMe)FMK (z-DEVD-fmk),an inhibitor of caspases,prevented caspase-3 activation and abrogated oridonin-induced cell death. Finally,oridonin treatment of the HeLa cell line downregulated the expression of the inhibitor of the apoptosis protein.Conclusion:Our results showed that oridonin-induced apoptosis involved several molecular pathways. Oridonin may suppress constitutively activated targets of phosphatidylinositol 3-kinase (Akt,FOXO,and GSK3) in the HeLa cell line,inhibiting the proliferation and induction of caspase-dependent apoptosis.

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

    Science.gov (United States)

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

    2014-01-01

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

  19. Akt regulates drug-induced cell death through Bcl-w downregulation.

    Directory of Open Access Journals (Sweden)

    Michela Garofalo

    Full Text Available Akt is a serine threonine kinase with a major role in transducing survival signals and regulating proteins involved in apoptosis. To find new interactors of Akt involved in cell survival, we performed a two-hybrid screening in yeast using human full-length Akt c-DNA as bait and a murine c-DNA library as prey. Among the 80 clones obtained, two were identified as Bcl-w. Bcl-w is a member of the Bcl-2 family that is essential for the regulation of cellular survival, and that is up-regulated in different human tumors, such as gastric and colorectal carcinomas. Direct interaction of Bcl-w with Akt was confirmed by immunoprecipitation assays. Subsequently, we addressed the function of this interaction: by interfering with the activity or amount of Akt, we have demonstrated that Akt modulates the amount of Bcl-w protein. We have found that inhibition of Akt activity may promote apoptosis through the downregulation of Bcl-w protein and the consequential reduction in interaction of Bcl-w with pro-apoptotic members of the Bcl-2 family. Our data provide evidence that Bcl-w is a new member of the Akt pathway and that Akt may induce anti-apoptotic signals at least in part through the regulation of the amount and activity of Bcl-w.

  20. DESC1, a novel tumor suppressor, sensitizes cells to apoptosis by downregulating the EGFR/AKT pathway in esophageal squamous cell carcinoma.

    Science.gov (United States)

    Ng, Hoi Yan; Ko, Josephine Mun-Yee; Yu, Valen Zhuoyou; Ip, Joseph Chok Yan; Dai, Wei; Cal, Santiago; Lung, Maria Li

    2016-06-15

    Esophageal cancer is ranked as the eighth most common cancer and the sixth leading cause of cancer deaths worldwide. To identify candidate tumor suppressor genes related to esophageal squamous cell carcinoma (ESCC) development, a cDNA microarray analysis was performed using paired tumor and nontumor tissue samples from ESCC patients. Differentially expressed in squamous cell carcinoma 1 (DESC1), which belongs to the Type II transmembrane serine protease family, was frequently downregulated in ESCC. This study aims to elucidate the molecular mechanism for the tumor suppressive function of DESC1 in ESCC. We show that DESC1 reduced cell viability and sensitized cells to apoptosis, when cells were under apoptotic stimuli. The proapoptotic effect of DESC1 was mediated through downregulating AKT1 activation and the restoration of AKT activation by the introduction of the constitutively active AKT, myr-AKT, abolished the apoptosis-sensitizing effect of DESC1. DESC1 also reduced EGFR protein level, which was abrogated when the proteolytic function of DESC1 was lost, suggesting that DESC1 cleaved EGFR and downregulated the EGFR/AKT pathway to favor apoptosis. The transmembrane localization and the structural domains provide an opportunity for DESC1 to interact with the extracellular environment. The importance of such interaction was highlighted by the finding that DESC1 reduced cell colony formation ability in three-dimensional culture. In line with this, DESC1 reduced tumor growth kinetics in the in vivo orthotopic tumorigenesis assay. Taken together, our novel findings suggest how DESC1 may suppress ESCC development by sensitizing cells to apoptosis under an apoptotic stimulus through downregulating the EGFR/AKT signaling pathway.

  1. Resveratrol Prevention of Diabetic Nephropathy Is Associated with the Suppression of Renal Inflammation and Mesangial Cell Proliferation: Possible Roles of Akt/NF-κB Pathway

    Directory of Open Access Journals (Sweden)

    Feng Xu

    2014-01-01

    Full Text Available The present study was to investigate the protection of resveratrol (RSV in diabetes associated with kidney inflammation and cell proliferation. Rat mesangial cell and streptozotocin-induced type 1 diabetes mouse model were used. In vitro, RSV attenuated high glucose-induced plasminogen activator inhibitor (PAI-1 expression and mesangial cell proliferation, as well as Akt and nuclear factor-kappa B (NF-κB activation. The similar results were recaptured in the experiment with Akt inhibitors. In vivo, mice were divided into three groups: control group, diabetes mellitus (DM group, and RSV-treated DM group. Compared with control group, the kidney weight to body weight ratio and albumin to creatinine ratio were increased in DM group, but not in RSV-treated DM group. Furthermore, the increased expression of PAI-1 and intercellular adhesion molecule-1 in diabetic renal cortex were also reduced by RSV administration. Besides, the kidney p-Akt/Akt ratio and NF-κB were significantly increased in DM group; however, these changes were reversed in RSV-treated DM group. Additionally, immunohistochemistry results indicated that RSV treatment reduced the density of proliferating cell nuclear antigen-positive cells significantly in glomeruli of diabetic mice. These results suggest that RSV prevents diabetes-induced renal inflammation and mesangial cell proliferation possibly through Akt/NF-κB pathway inhibition.

  2. Berberine induces dedifferentiation by actin cytoskeleton reorganization via phosphoinositide 3-kinase/Akt and p38 kinase pathways in rabbit articular chondrocytes.

    Science.gov (United States)

    Yu, Seon-Mi; Cho, Hongsik; Kim, Gwang-Hoon; Chung, Ki-Wha; Seo, Sung-Yum; Kim, Song-Ja

    2016-04-01

    Osteoarthritis is a nonrheumatologic joint disease characterized by progressive degeneration of the cartilage extracellular matrix. Berberine (BBR) is an isoquinoline alkaloid used in traditional Chinese medicine, the majority of which is extracted from Huang Lian (Coptis chinensis). Although numerous studies have revealed the anticancer activity of BBR, its effects on normal cells, such as chondrocytes, and the molecular mechanisms underlying its actions remain elusive. Therefore, we examined the effects of BBR on rabbit articular chondrocytes, and the underlying molecular mechanisms, focusing on actin cytoskeletal reorganization. BBR induced dedifferentiation by inhibiting activation of phosphoinositide-3(PI3)-kinase/Akt and p38 kinase. Furthermore, inhibition of p38 kinase and PI3-kinase/Akt with SB203580 and LY294002, respectively, accelerated the BBR-induced dedifferentiation. BBR also caused actin cytoskeletal architecture reorganization and, therefore, we investigated if these effects were involved in the dedifferentiation. Disruption of the actin cytoskeleton by cytochalasin D reversed the BBR-induced dedifferentiation by activating PI3-kinase/Akt and p38 kinase. In contrast, the induction of actin filament aggregation by jasplakinolide accelerated the BBR-induced dedifferentiation via PI3-kinase/Akt inhibition and p38 kinase activation. Taken together, these data suggest that BBR strongly induces dedifferentiation, and actin cytoskeletal reorganization is a crucial requirement for this effect. Furthermore, the dedifferentiation activity of BBR appears to be mediated via PI3-kinase/Akt and p38 kinase pathways in rabbit articular chondrocytes. PMID:26851252

  3. Cell type-dependent Erk-Akt pathway crosstalk regulates the proliferation of fetal neural progenitor cells.

    Science.gov (United States)

    Rhim, Ji Heon; Luo, Xiangjian; Gao, Dongbing; Xu, Xiaoyun; Zhou, Tieling; Li, Fuhai; Wang, Ping; Wong, Stephen T C; Xia, Xiaofeng

    2016-01-01

    Neural progenitor (NP) cells are the multipotent cells that produce neurons and glia in the central nervous system. Compounds regulating their proliferation are key to both understanding brain development and unlocking their potential in regenerative repair. We discuss a chemical screen that unexpectedly identified inhibitors of Erk signaling potently promoting the self-renewing divisions of fetal NP cells. This occurred through crosstalk between Erk and Akt signaling cascades. The crosstalk mechanism is cell type-specific, and is not detected in adult NP cells as well as brain tumor cells. The mechanism was also shown to be independent from the GSK-3 signaling pathway, which has been reported to be a major regulator of NP cell homeostasis and inhibitors to which were also identified in the screen. In vitro Erk inhibition led to the prolonged rapid expansion of fetal NP cells while retaining their multipotency. In vivo inhibitor administration significantly inhibited the neuronal differentiation, and resulted in increased proliferative progenitor cells in the ventricular/subventricular zone (VZ/SVZ) of the embryonic cortex. Our results uncovered a novel regulating pathway for NP cell proliferation in the developing brain. The discovery provides a pharmacological basis for in vitro expansion and in vivo manipulation of NP cells. PMID:27211495

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

    Directory of Open Access Journals (Sweden)

    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.

  5. A mathematical model of phosphorylation AKT in Acute Myeloid Leukemia

    Science.gov (United States)

    Adi, Y. A.; Kusumo, F. A.; Aryati, L.; Hardianti, M. S.

    2016-04-01

    In this paper we consider a mathematical model of PI3K/AKT signaling pathways in phosphorylation AKT. PI3K/AKT pathway is an important mediator of cytokine signaling implicated in regulation of hematopoiesis. Constitutive activation of PI3K/AKT signaling pathway has been observed in Acute Meyloid Leukemia (AML) it caused by the mutation of Fms-like Tyrosine Kinase 3 in internal tandem duplication (FLT3-ITD), the most common molecular abnormality associated with AML. Depending upon its phosphorylation status, protein interaction, substrate availability, and localization, AKT can phosphorylate or inhibite numerous substrates in its downstream pathways that promote protein synthesis, survival, proliferation, and metabolism. Firstly, we present a mass action ordinary differential equation model describing AKT double phosphorylation (AKTpp) in a system with 11 equations. Finally, under the asumtion enzyme catalyst constant and steady state equilibrium, we reduce the system in 4 equation included Michaelis Menten constant. Simulation result suggested that a high concentration of PI3K and/or a low concentration of phospatase increased AKTpp activation. This result also indicates that PI3K is a potential target theraphy in AML.

  6. 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:

  7. Apigenin inhibits HGF-promoted invasive growth and metastasis involving blocking PI3K/Akt pathway and β4 integrin function in MDA-MB-231 breast cancer cells

    International Nuclear Information System (INIS)

    Hepatocyte growth factor (HGF) and its receptor, Met, known to control invasive growth program have recently been shown to play crucial roles in the survival of breast cancer patients. The diet-derived flavonoids have been reported to possess anti-invasion properties; however, knowledge on the pharmacological and molecular mechanisms in suppressing HGF/Met-mediated tumor invasion and metastasis is poorly understood. In our preliminary study, we use HGF as an invasive inducer to investigate the effect of flavonoids including apigenin, naringenin, genistein and kaempferol on HGF-dependent invasive growth of MDA-MB-231 human breast cancer cells. Results show that apigenin presents the most potent anti-migration and anti-invasion properties by Boyden chamber assay. Furthermore, apigenin represses the HGF-induced cell motility and scattering and inhibits the HGF-promoted cell migration and invasion in a dose-dependent manner. The effect of apigenin on HGF-induced signaling activation involving invasive growth was evaluated by immunoblotting analysis, it shows that apigenin blocks the HGF-induced Akt phosphorylation but not Met, ERK, and JNK phosphorylation. In addition to MDA-MB-231 cells, apigenin exhibits inhibitory effect on HGF-induced Akt phosphorylation in hepatoma SK-Hep1 cells and lung carcinoma A549 cells. By indirect immunofluorescence microscopy assay, apigenin inhibits the HGF-induced clustering of β4 integrin at actin-rich adhesive site and lamellipodia through PI3K-dependent manner. Treatment of apigenin inhibited HGF-stimulated integrin β4 function including cell-matrix adhesion and cell-endothelial cells adhesion in MDA-MB-231 cells. By Akt-siRNA transfection analysis, it confirmed that apigenin inhibited HGF-promoted invasive growth involving blocking PI3K/Akt pathway. Finally, we evaluated the effect of apigenin on HGF-promoted metastasis by lung colonization of tumor cells in nude mice and organ metastasis of tumor cells in chick embryo. By

  8. Effects of circulation hyperthermic perfusion chemotherapy on tumor marker content and PI3K/Akt/mTOR pathway function of gastric cancer peritoneal effusion patients

    Institute of Scientific and Technical Information of China (English)

    Li Ding

    2015-01-01

    Objective: To study the effects of circulation hyperthermic perfusion chemotherapy on tumor marker content and PI3K/Akt/mTOR pathway function of gastric cancer peritoneal effusion patients. Methods: 80 cases of gastric cancer peritoneal effusion patients in our hospital from May 2013 to August 2014 were enrolled and randomly divided into two groups. Observation group received circulation hyperthermic perfusion chemotherapy; control group received conventional perfusion chemotherapy. Then blood tumor markers, LAG3 and HSP content, PI3K-AKT-mTOR signal molecules were assayed. Results:(1) tumor markers: DDK1, EXOSC2 contents and PGR ratio of observation group were lower than those of control group; PGI and PGII contents were higher than those of control group; (2) LAG3 and HSP contents: HSP27 and HSP90 contents of observation group were lower than those of control group; sLAG-3 content was higher than that of control group; (3) signal molecules: mRNA contents of PI3K, Akt and mTOR molecules of observation group were lower than those of control group. Conclusion: Circulation hyperthermic perfusion chemotherapy is helpful to kill tumor cells, reduce tumor marker releasing into blood, regulate LAG3 and HSP expression and inhibit PI3K/Akt/mTOR pathway function; it’s an ideal method for treating peritoneal effusion.

  9. Ethyl pyruvate inhibits proliferation and induces apoptosis of hepatocellular carcinoma via regulation of the HMGB1–RAGE and AKT pathways

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Ping; Dai, Weiqi; Wang, Fan; Lu, Jie; Shen, Miao; Chen, Kan; Li, Jingjing; Zhang, Yan; Wang, Chengfen; Yang, Jing; Zhu, Rong; Zhang, Huawei; Zheng, Yuanyuan; Guo, Chuan-Yong, E-mail: guochuanyong@hotmail.com; Xu, Ling, E-mail: xuling606@sina.com

    2014-01-24

    Highlights: • Ethyl pyruvate inhibits liver cancer. • Promotes apoptosis. • Decreased the expression of HMGB1, p-Akt. - Abstract: Ethyl pyruvate (EP) was recently identified as a stable lipophilic derivative of pyruvic acid with significant antineoplastic activities. The high mobility group box-B1 (HMGB1)–receptor for advanced glycation end-products (RAGE) and the protein kinase B (Akt) pathways play a crucial role in tumorigenesis and development of many malignant tumors. We tried to observe the effects of ethyl pyruvate on liver cancer growth and explored its effects in hepatocellular carcinoma model. In this study, three hepatocellular carcinoma cell lines were treated with ethyl pyruvate. An MTT colorimetric assay was used to assess the effects of EP on cell proliferation. Flow cytometry and TUNEL assays were used to analyze apoptosis. Real-time PCR, Western blotting and immunofluorescence demonstrated ethyl pyruvate reduced the HMGB1–RAGE and AKT pathways. The results of hepatoma orthotopic tumor model verified the antitumor effects of ethyl pyruvate in vivo. EP could induce apoptosis and slow the growth of liver cancer. Moreover, EP decreased the expression of HMGB1, RAGE, p-AKT and matrix metallopeptidase-9 (MMP9) and increased the Bax/Bcl-2 ratio. In conclusion, this study demonstrates that ethyl pyruvate induces apoptosis and cell-cycle arrest in G phase in hepatocellular carcinoma cells, plays a critical role in the treatment of cancer.

  10. Glimepiride promotes osteogenic differentiation in rat osteoblasts via the PI3K/Akt/eNOS pathway in a high glucose microenvironment.

    Science.gov (United States)

    Ma, Pan; Gu, Bin; Xiong, Wei; Tan, Baosheng; Geng, Wei; Li, Jun; Liu, Hongchen

    2014-01-01

    Our previous studies demonstrated that glimepiride enhanced the proliferation and differentiation of osteoblasts and led to activation of the PI3K/Akt pathway. Recent genetic evidence shows that endothelial nitric oxide synthase (eNOS) plays an important role in bone homeostasis. In this study, we further elucidated the roles of eNOS, PI3K and Akt in bone formation by osteoblasts induced by glimepiride in a high glucose microenvironment. We demonstrated that high glucose (16.5 mM) inhibits the osteogenic differentiation potential and proliferation of rat osteoblasts. Glimepiride activated eNOS expression in rat osteoblasts cultured with two different concentrations of glucose. High glucose-induced osteogenic differentiation was significantly enhanced by glimepiride. Down-regulation of PI3K P85 levels by treatment with LY294002 (a PI3K inhibitor) led to suppression of P-eNOS and P-AKT expression levels, which in turn resulted in inhibition of RUNX2, OCN and ALP mRNA expression in osteoblasts induced by glimepiride at both glucose concentrations. ALP activity was partially inhibited by 10 µM LY294002. Taken together, our results demonstrate that glimepiride-induced osteogenic differentiation of osteoblasts occurs via eNOS activation and is dependent on the PI3K/Akt signaling pathway in a high glucose microenvironment. PMID:25391146

  11. Glimepiride promotes osteogenic differentiation in rat osteoblasts via the PI3K/Akt/eNOS pathway in a high glucose microenvironment.

    Directory of Open Access Journals (Sweden)

    Pan Ma

    Full Text Available Our previous studies demonstrated that glimepiride enhanced the proliferation and differentiation of osteoblasts and led to activation of the PI3K/Akt pathway. Recent genetic evidence shows that endothelial nitric oxide synthase (eNOS plays an important role in bone homeostasis. In this study, we further elucidated the roles of eNOS, PI3K and Akt in bone formation by osteoblasts induced by glimepiride in a high glucose microenvironment. We demonstrated that high glucose (16.5 mM inhibits the osteogenic differentiation potential and proliferation of rat osteoblasts. Glimepiride activated eNOS expression in rat osteoblasts cultured with two different concentrations of glucose. High glucose-induced osteogenic differentiation was significantly enhanced by glimepiride. Down-regulation of PI3K P85 levels by treatment with LY294002 (a PI3K inhibitor led to suppression of P-eNOS and P-AKT expression levels, which in turn resulted in inhibition of RUNX2, OCN and ALP mRNA expression in osteoblasts induced by glimepiride at both glucose concentrations. ALP activity was partially inhibited by 10 µM LY294002. Taken together, our results demonstrate that glimepiride-induced osteogenic differentiation of osteoblasts occurs via eNOS activation and is dependent on the PI3K/Akt signaling pathway in a high glucose microenvironment.

  12. Functional switching of ATM: sensor of DNA damage in proliferating cells and mediator of Akt survival signal in post-mitotic human neuron-like cells

    Institute of Scientific and Technical Information of China (English)

    Yan Li; Hua Xiong; Da-Qing Yang

    2012-01-01

    Ataxia-telangiectasia (A-T) is an autosomal recessive disorder characterized by cerebellar ataxia and oculocutaneous telangiectasias.The gene mutated in this disease,ATM (A-T,mutated),encodes a 370-kDa Ser/Thr protein kinase.ATM not only mediates cellular response to DNA damage but also acts as an activator of Akt in response to insulin.However,despite intensive studies,the mechanism underlying the neuronal degeneration symptoms of human A-T is still poorly understood.We found that the topoisomerase inhibitors etoposide and camptothecin readily induced apoptosis in undifferentiated proliferating SH-SY5Y cells but could not induce apoptosis in neuronally differentiated SH-SY5Y cells.In addition,etoposide induced p53 phosphorylation and H2AX foci formation in proliferating SH-SY5Y cells but failed to do so in differentiated SH-SY5Y cells.Moreover,while inhibition of ATM in undifferentiated SH-SY5Y cells partially protected them from etoposide-induced apoptosis,the same treatment had no effect on cell viability in differentiated SH-SY5Y cells.These results suggest that DNA damage or defective response to DNA damage is not the cause of neuronal cell death in human A-T.In contrast,we discovered that Akt phosphorylation was inhibited when ATM activity was suppressed in differentiated SH-SY5Y cells.Furthermore,inhibition of ATM induced apoptosis following serum starvation in neuronally differentiated SH-SY5Y cells but could not trigger apoptosis under the same conditions in undifferentiated proliferating SH-SY5Y cells.These results demonstrate that ATM mediates the Akt signaling and promotes cell survival in neuron-like human SH-SY5Y cells,suggesting that impaired activation of Akt is the reason for neuronal degeneration in human A-T.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  14. 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

  15. Decreased function of survival motor neuron protein impairs endocytic pathways.

    Science.gov (United States)

    Dimitriadi, Maria; Derdowski, Aaron; Kalloo, Geetika; Maginnis, Melissa S; O'Hern, Patrick; Bliska, Bryn; Sorkaç, Altar; Nguyen, Ken C Q; Cook, Steven J; Poulogiannis, George; Atwood, Walter J; Hall, David H; Hart, Anne C

    2016-07-26

    Spinal muscular atrophy (SMA) is caused by depletion of the ubiquitously expressed survival motor neuron (SMN) protein, with 1 in 40 Caucasians being heterozygous for a disease allele. SMN is critical for the assembly of numerous ribonucleoprotein complexes, yet it is still unclear how reduced SMN levels affect motor neuron function. Here, we examined the impact of SMN depletion in Caenorhabditis elegans and found that decreased function of the SMN ortholog SMN-1 perturbed endocytic pathways at motor neuron synapses and in other tissues. Diminished SMN-1 levels caused defects in C. elegans neuromuscular function, and smn-1 genetic interactions were consistent with an endocytic defect. Changes were observed in synaptic endocytic proteins when SMN-1 levels decreased. At the ultrastructural level, defects were observed in endosomal compartments, including significantly fewer docked synaptic vesicles. Finally, endocytosis-dependent infection by JC polyomavirus (JCPyV) was reduced in human cells with decreased SMN levels. Collectively, these results demonstrate for the first time, to our knowledge, that SMN depletion causes defects in endosomal trafficking that impair synaptic function, even in the absence of motor neuron cell death. PMID:27402754

  16. DNA Synthesis during Endomitosis Is Stimulated by Insulin via the PI3K/Akt and TOR Signaling Pathways in the Silk Gland Cells of Bombyx mori

    Directory of Open Access Journals (Sweden)

    Yaofeng Li

    2015-03-01

    Full Text Available Silk gland cells undergo multiple endomitotic cell cycles during silkworm larval ontogeny. Our previous study demonstrated that feeding is required for continued endomitosis in the silk gland cells of silkworm larvae. Furthermore, the insulin signaling pathway is closely related to nutritional signals. To investigate whether the insulin signaling pathway is involved in endomitosis in silk gland cells, in this study, we initially analyzed the effects of bovine insulin on DNA synthesis in endomitotic silk gland cells using 5-bromo-2'-deoxyuridine (BrdU labeling technology, and found that bovine insulin can stimulate DNA synthesis. Insulin signal transduction is mainly mediated via phosphoinositide 3-kinase (PI3K/Akt, the target of rapamycin (TOR and the extracellular signal-regulated kinase (ERK pathways in vertebrates. We ascertained that these three pathways are involved in DNA synthesis in endomitotic silk gland cells using specific inhibitors against each pathway. Moreover, we investigated whether these three pathways are involved in insulin-stimulated DNA synthesis in endomitotic silk gland cells, and found that the PI3K/Akt and TOR pathways, but not the ERK pathway, are involved in this process. These results provide an important theoretical foundation for the further investigations of the mechanism underlying efficient endomitosis in silk gland cells.

  17. PI-3K/Akt/GSK-3β signaling cascades stimulated by insulin like growth factor-I contribute to multiple myeloma cells proliferation and survival

    Institute of Scientific and Technical Information of China (English)

    WANG Meng-chang; FU Xue-de; LI Man-xiang

    2006-01-01

    @@ Multiple myeloma is characterized by the accumulation of malignant plasma cells in the bone marrow. Significant progress in molecular mechanisms of signaling pathways underlying the survival and/or proliferation of these cells has been achieved.

  18. Constitutive phosphorylation of the mTORC2/Akt/4E-BP1 pathway in newly derived canine hemangiosarcoma cell lines

    Directory of Open Access Journals (Sweden)

    Murai Atsuko

    2012-07-01

    Full Text Available Abstract Background Canine hemangiosarcoma (HSA is a malignant tumor with poor long-term prognosis due to development of metastasis despite aggressive treatment. The phosphatidyl-inositol-3 kinase/Akt/mammalian target of rapamycin (PI3K/Akt/mTOR pathway is involved in its endothelial pathologies; however, it remains unknown how this pathway plays a role in canine HSA. Here, we characterized new canine HSA cell lines derived from nude mice-xenografted canine HSAs and investigated the deregulation of the signaling pathways in these cell lines. Results Seven canine HSA cell lines were established from 3 xenograft canine HSAs and showed characteristics of endothelial cells (ECs, that is, uptake of acetylated low-density lipoprotein and expression of canine-specific CD31 mRNA. They showed varied morphologies and mRNA expression levels for VEGF-A, bFGF, HGF, IGF-I, EGF, PDGF-B, and their receptors. Cell proliferation was stimulated by these growth factors and fetal bovine serum (FBS in 1 cell line and by FBS alone in 3 cell lines. However, cell proliferation was not stimulated by growth factors and FBS in the remaining 3 cell lines. Phosphorylated p44/42 Erk1/2 was increased by FBS stimulation in 4 cell lines. In contrast, phosphorylation of Akt at Ser473, mTOR complex 1 (mTORC1 at Ser2448, and eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1 at Ser65 was high in serum-starved condition and not altered by FBS stimulation in 6 cell lines, despite increased phosphorylation of these residues in normal canine ECs. This suggested that the mTORC2/Akt/4E-BP1 pathway was constitutively activated in these 6 canine HSA cell lines. After cell inoculation into nude mice, canine HSA tumors were formed from 4 cell lines and showed Akt and 4E-BP1 phosphorylation identical to the parental cell lines. Conclusions Our findings suggest that the present cell lines may be useful tools for investigating the role of the mTORC2/Akt/4E-BP1 pathway in

  19. 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.

  20. Reactive oxygen species via redox signaling to PI3K/AKT pathway contribute to the malignant growth of 4-hydroxy estradiol-transformed mammary epithelial cells.

    Directory of Open Access Journals (Sweden)

    Victor O Okoh

    Full Text Available The purpose of this study was to investigate the effects of 17-β-estradiol (E2-induced reactive oxygen species (ROS on the induction of mammary tumorigenesis. We found that ROS-induced by repeated exposures to 4-hydroxy-estradiol (4-OH-E2, a predominant catechol metabolite of E2, caused transformation of normal human mammary epithelial MCF-10A cells with malignant growth in nude mice. This was evident from inhibition of estrogen-induced breast tumor formation in the xenograft model by both overexpression of catalase as well as by co-treatment with Ebselen. To understand how 4-OH-E2 induces this malignant phenotype through ROS, we investigated the effects of 4-OH-E2 on redox-sensitive signal transduction pathways. During the malignant transformation process we observed that 4-OH-E2 treatment increased AKT phosphorylation through PI3K activation. The PI3K-mediated phosphorylation of AKT in 4-OH-E2-treated cells was inhibited by ROS modifiers as well as by silencing of AKT expression. RNA interference of AKT markedly inhibited 4-OH-E2-induced in vitro tumor formation. The expression of cell cycle genes, cdc2, PRC1 and PCNA and one of transcription factors that control the expression of these genes - nuclear respiratory factor-1 (NRF-1 was significantly up-regulated during the 4-OH-E2-mediated malignant transformation process. The increased expression of these genes was inhibited by ROS modifiers as well as by silencing of AKT expression. These results indicate that 4-OH-E2-induced cell transformation may be mediated, in part, through redox-sensitive AKT signal transduction pathways by up-regulating the expression of cell cycle genes cdc2, PRC1 and PCNA, and the transcription factor - NRF-1. In summary, our study has demonstrated that: (i 4-OH-E2 is one of the main estrogen metabolites that induce mammary tumorigenesis and (ii ROS-mediated signaling leading to the activation of PI3K/AKT pathway plays an important role in the generation of 4-OH-E2

  1. Interactions of the integrin subunit beta1A with protein kinase B/Akt, p130Cas and paxillin contribute to regulation of radiation survival

    DEFF Research Database (Denmark)

    Seidler, Julia; Durzok, Rita; Brakebusch, Cord;

    2005-01-01

    in presence or absence of growth factors or inhibitors for phosphatidylinositol-3 kinase (PI3K), i.e. Ly294002 and wortmannin. In addition to colony formation, protein kinase B/Akt (PKB/Akt) kinase activity, focal adhesion kinase (FAK), p130Cas, paxillin and c-Jun N2-terminal kinase (JNK) expression...... and phosphorylation were analyzed by Western blot technique. RESULTS: Adhesion of GD25beta1A cells to extracellular matrix proteins or beta1-IgG resulted in growth factor-independent radiation survival. In contrast, serum starved GD25beta1B cells showed a significant (P...25beta1B cells, which express mutant beta1B-integrins, were compared in terms of radiation survival and beta1-integrin signaling. MATERIALS AND METHODS: Cells grown on fibronectin, collagen-III, laminin, vitronectin, anti-beta1-integrin-IgG (beta1-IgG) or poly-l-lysine were irradiated with 0-6Gy...

  2. 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.

  3. Erythropoietin prevents PC12 cells from beta-amyloid-induced apoptosis via PI3K⁄Akt pathway

    Directory of Open Access Journals (Sweden)

    Zhi-Kun Sun

    2012-02-01

    Full Text Available Abstract Background Several studies indicated that Erythropoietin (Epo may provide remarkable neuroprotection in some neurological diseases. It also showed the significant decrease of Epo immunoreactivity in the cerebral cortex and hippocampus in aged rats, suggesting the role of Epo in the pathogenesis of age-related neurodegenerative diseases such as AD. Methods The protective effect of Epo was studied in differentiated PC12 cells treated with Abeta. The viability of the cells, the apoptosis of the cells and the level of Bax, Bcl-2, cleaved caspase-3 and cleaved PARP expression were detected by MTT, Hoechst 33258 staining and Western blotting respectively. Results 20 μM Abeta (25-35 could induce a decreased viability and a increased apoptosis in PC12 cell in a time-dependent manner. However, 20 μM Abeta (35-25 had no effect on cell viability and apoptosis. Western blot analysis also showed that Abeta(25-35 treatment could decrease the expression of Bcl-2 (P P P P (25-35 (P P Conclusions Epo prevented cell injuries in PC12 cells exposed to the Abeta(25-35 and this effect may depend on the PI3K⁄Akt pathway. Our study provided an important evidence for the potential application of Epo in the therapy of Alzheimer's disease.

  4. Human urine extract CDA-2 induces apoptosis of myelodysplastic syndrome-derived MUTZ-1 cells through the PI3K/Akt signaling pathway in a caspase-3-dependent manner

    Institute of Scientific and Technical Information of China (English)

    Jian HUANG; Min YANG; Hui LIU; Jie JIN

    2008-01-01

    Aim: The aim of this study was to investigate the antitumoral activity of human urine extract against myelodysplastic syndrome (MDS)-derived MUTZ-1 cells in vitro and in vivo. Methods: The MDS-refractory anemia with excess of blasts (RAEB)-derived MUTZ-1 cell line was used to examine the effects of a human urine preparation, CDA-2, on the induction of growth arrest and apoptosis. Apoptotic proteins, including caspase family, Bcl-2 family, the inhibitor of apoptosis protein (IAP) family, and the F-LICE-like inhibitory protein (FLIP), as well as cell cycle-associated proteins were studied. The phosphoinositide 3 ki- nase (PI3K)/Akt survival signaling pathway and the NF-k B pathway were also examined. The caspase-3 inhibitor Z-DEVD-fmk was used to examine the involve- ment of caspase-3 and poly (ADP-ribose) polymerase (PARP). PI3K inhibitor LY294002 was used to examine the involvement of the PI3K/Akt signaling path- way in this apoptosis-inducing effect. MUTZ-1 cell xenografted serious com- bined immunodeficiency disease mice were used for the in vivo study. Results: We found that CDA-2 could induce growth arrest and apoptosis of MUTZ-l cells in vitro and in vivo. The main mechanisms were related to the inhibition of PI3Kp110or expression at the transcriptional level, which inactivated the phos- phorylation of Akt involving the prevention NF-KB phosphorylation and nuclear translocation, the downregulation of the IAP family and FLIPL protein, and the dephosphorylation of the Bad protein, which then triggered the activation of the caspase cascades. This phenomenon could be inhibited by the PI3K inhibitor LY294002 and caspase-3 inhibitor Z-DEVD-fmk. Conclusion: Our results demon- strate the presence of active components in the human urine extract that can induce the growth arrest and apoptosis of MDS-RAEB-derived MUTZ-1 cells and may involve the PI3K/Akt signaling pathway in a caspase-3-dependent manner. This may provide new insights for the treatment of high-risk MDS.

  5. Dietary Lycium barbarum Polysaccharide Induces Nrf2/ARE Pathway and Ameliorates Insulin Resistance Induced by High-Fat via Activation of PI3K/AKT Signaling

    Directory of Open Access Journals (Sweden)

    Yi Yang

    2014-01-01

    Full Text Available Lycium barbarum polysaccharide (LBP, an antioxidant from wolfberry, displays the antioxidative and anti-inflammatory effects on experimental models of insulin resistance in vivo. However, the effective mechanism of LBP on high-fat diet-induced insulin resistance is still unknown. The objective of the study was to investigate the mechanism involved in LBP-mediated phosphatidylinositol 3-kinase (PI3K/AKT/Nrf2 axis against high-fat-induced insulin resistance. HepG2 cells were incubated with LBP for 12 hrs in the presence of palmitate. C57BL/6J mice were fed a high-fat diet supplemented with LBP for 24 weeks. We analyzed the expression of nuclear factor-E2-related factor 2 (Nrf2, Jun N-terminal kinases (JNK, and glycogen synthase kinase 3β (GSK3β involved in insulin signaling pathway in vivo and in vitro. First, LBP significantly induced phosphorylation of Nrf2 through PI3K/AKT signaling. Second, LBP obviously increased detoxification and antioxidant enzymes expression and reduced reactive oxygen species (ROS levels via PI3K/AKT/Nrf2 axis. Third, LBP also regulated phosphorylation levels of GSK3β and JNK through PI3K/AKT signaling. Finally, LBP significantly reversed glycolytic and gluconeogenic genes expression via the activation of Nrf2-mediated cytoprotective effects. In summary, LBP is novel antioxidant against insulin resistance induced by high-fat diet via activation of PI3K/AKT/Nrf2 pathway.

  6. Effects of exosomes derived from MDA-MB-231 on proliferation of endothelial cells and the role of MAPK/ERK and PI3K/Akt pathways

    Directory of Open Access Journals (Sweden)

    Shuang LONG

    2012-11-01

    Full Text Available Objective  To investigate the effects of exosomes derived from breast cancer cell line MDA-MB-231 on proliferation of human umbilical cord vein endothelial cells (HUVECs, and evaluate the role of MAPK/ERK and PI3K/Akt signal transduction pathway during the process. Methods  Exosomes were derived and purified from MDA-MB-231 by cryogenic ultracentrifugation and density gradient centrifugation. MTT assay was carried out for measurement of cell proliferation in HUVECs with exosome of 50, 100, 200 and 400μg/ml. The states of cell cycle of HUVECs co-cultured with 200μg/ml exosomes were detected by flow cytometry. The effects of 200μg/ml exosomes on the expression of ERK, Akt and phosphorylated ERK, Akt in HUVECs were detected with Western blotting. Results  Exosomes derived from MDA-MB-231 significantly promoted HUVECs proliferation in a classical time-and dose-dependent manner. Flow cytometry revealed that, co-cultured with 200μg/ml exosomes for 24h, S-phase cells in HUVECs increased, while G1/S phase cells in HUVECs decreased. Western blotting showed that, cocultured with 200μg/ml exosomes for 24h, 48h and 72h, the expressions of phosphorylated ERK and Akt were up-regulated in a time-dependent manner. Conclusion  Exosomes derived from breast cancer cell line MDA-MB-231 may promote HUVECs proliferation, the changes in cell cycle and the continuous activation of the MAPK/ERK and PI3K/Akt signal transduction pathways may be the underlying mechanism.

  7. 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.

  8. Nitidine chloride inhibits proliferation, induces apoptosis via the Akt pathway and exhibits a synergistic effect with doxorubicin in ovarian cancer cells.

    Science.gov (United States)

    Ding, Feng; Liu, Tianfeng; Yu, Nina; Li, Shihong; Zhang, Xiaofei; Zheng, Guanghong; Lv, Chunming; Mou, Kai; Xu, Jia; Li, Bo; Wang, Surong; Song, Haibo

    2016-09-01

    Nitidine chloride (NC) exhibits anti-tumor properties in various types of tumor. However, to the best of our knowledge there is no previous evidence of NC involvement in the apoptosis or proliferation of ovarian cancer cells and the underlying molecular mechanisms. The present study aimed to investigate the influence of NC on the viability and apoptosis of ovarian cancer cells and the synergistic effect NC and doxorubicin (DOX) may have on ovarian cancer cells. The viability and proliferation of ovarian cancer cells were examined using a methyl thiazolyl tetrazolium assay and 3H-thymidine incorporation assay. The apoptotic rate of ovarian cancer cells was detected by flow cytometry. The expression of apoptosis‑associated proteins and Akt serine/threonine kinase 1 (Akt) were determined by western blot analysis following NC treatment. The inhibitory effect of NC on the proliferation of ovarian cancer cells was demonstrated in a time and dose‑dependent manner. The pro-apoptotic effect of NC on ovarian cancer cells was also observed. It was determined that NC significantly downregulated the protein expression levels of B‑cell CLL/lymphoma 2 (Bcl-2) and upregulated the expression of Bcl‑2‑associated X protein, p53, caspase‑3 and ‑9. NC suppressed Akt phosphorylation. Additionally, the present study demonstrated that the effect of NC on the proliferation and apoptosis of ovarian cancer cells was Akt‑dependent by using the phosphatidylinositol-4,5-bisphosphate 3-kinase/Akt signaling pathway inhibitor, LY294002. NC exhibited a synergistic inhibitory effect on the viability of ovarian cancer cells when combined with DOX. The current study demonstrated that NC inhibited the proliferation and induced the apoptosis of ovarian cancer cells via the Akt signaling pathway and highlighted its potential clinical application for the treatment of ovarian cancer. PMID:27485415

  9. Mechanical Stimulation and IGF-1 Enhance mRNA Translation Rate in Osteoblasts Via Activation of the AKT-mTOR Pathway.

    Science.gov (United States)

    Bakker, Astrid D; Gakes, Tom; Hogervorst, Jolanda M A; de Wit, Gerard M J; Klein-Nulend, Jenneke; Jaspers, Richard T

    2016-06-01

    Insulin-like growth factor-1 (IGF-1) is anabolic for muscle by enhancing the rate of mRNA translation via activation of AKT and subsequent activation of the mammalian target of rapamycin complex 1 (mTOR), thereby increasing cellular protein production. IGF-1 is also anabolic for bone, but whether the mTOR pathway plays a role in the rate of bone matrix protein production by osteoblasts is unknown. We hypothesized that anabolic stimuli such as mechanical loading and IGF-1 stimulate protein synthesis in osteoblasts via activation of the AKT-mTOR pathway. MC3T3-E1 osteoblasts were either or not subjected for 1 h to mechanical loading by pulsating fluid flow (PFF) or treated with or without human recombinant IGF-1 (1-100 ng/ml) for 0.5-6 h, to determine phosphorylation of AKT and p70S6K (downstream of mTOR) by Western blot. After 4 days of culture with or without the mTOR inhibitor rapamycin, total protein, DNA, and gene expression were quantified. IGF-1 (100 ng/ml) reduced IGF-1 gene expression, although PFF enhanced IGF-1 expression. IGF-1 did not affect collagen-I gene expression. IGF-1 dose-dependently enhanced AKT and p70S6K phosphorylation at 2 and 6 h. PFF enhanced phosphorylation of AKT and p70S6K already within 1 h. Both IGF-1 and PFF enhanced total protein per cell by ∼30%, but not in the presence of rapamycin. Our results show that IGF-1 and PFF activate mTOR, thereby stimulating the rate of mRNA translation in osteoblasts. The known anabolic effect of mechanical loading and IGF-1 on bone may thus be partly explained by mTOR-mediated enhanced protein synthesis in osteoblasts. PMID:26505782

  10. Quercetin ameliorates ischemia/reperfusion-induced cognitive deficits by inhibiting ASK1/JNK3/caspase-3 by enhancing the Akt signaling pathway.

    Science.gov (United States)

    Pei, Bing; Yang, Miaomiao; Qi, Xiaoyan; Shen, Xin; Chen, Xing; Zhang, Fayong

    2016-09-01

    Cerebral ischemia/reperfusion (I/R) is a major cause of severe disability and death all worldwide. However, therapeutic options to minimize the detrimental effects of cerebral I/R injury are limited. Recent research has demonstrated that quercetin mediates neuroprotective effects associated with the activation of the Akt signaling pathway in the cerebral I/R brain. Therefore, the aim of this study was to further investigate the mechanisms of cognitive deficits induced by cerebral I/R injury and the effects of quercetin on these mechanisms. First, we assessed anxiety-like behavioral and cognitive impairment using the open field test and the Morris water maze test, respectively. Next, we examined the severity of apoptosis by staining hippocampal neurons by the Cresyl violet method. Third, we used western blot analysis to investigate the expression of total and phosphorylated Akt, ASK1, JNK3, c-Jun and caspase-3 after I/R injury. Our results revealed that mice subjected to bilateral common carotid occlusion exhibited severe anxiety-like behavior, learning and memory impairment, cell damage and apoptosis. These severe effects were attenuated by administration of quercetin. Further, western blot analysis revealed that quercetin increased p-Akt expression and decreased p-ASK1, p-JNK3 and cleaved caspase-3 expression after cerebral I/R injury and led to inhibition of neuronal apoptosis. Conversely, treatment with LY294002 (a selective inhibitor of Akt1) reversed the effects of quercetin. In conclusion, these findings highlight the important role of quercetin in protecting against cognitive deficits and inhibiting neuronal apoptosis via the Akt signaling pathway. We believe that quercetin might prove to be a useful therapeutic component in treating cerebral I/R diseases in the near future. PMID:27450812

  11. Mechanical Stimulation and IGF-1 Enhance mRNA Translation Rate in Osteoblasts Via Activation of the AKT-mTOR Pathway.

    Science.gov (United States)

    Bakker, Astrid D; Gakes, Tom; Hogervorst, Jolanda M A; de Wit, Gerard M J; Klein-Nulend, Jenneke; Jaspers, Richard T

    2016-06-01

    Insulin-like growth factor-1 (IGF-1) is anabolic for muscle by enhancing the rate of mRNA translation via activation of AKT and subsequent activation of the mammalian target of rapamycin complex 1 (mTOR), thereby increasing cellular protein production. IGF-1 is also anabolic for bone, but whether the mTOR pathway plays a role in the rate of bone matrix protein production by osteoblasts is unknown. We hypothesized that anabolic stimuli such as mechanical loading and IGF-1 stimulate protein synthesis in osteoblasts via activation of the AKT-mTOR pathway. MC3T3-E1 osteoblasts were either or not subjected for 1 h to mechanical loading by pulsating fluid flow (PFF) or treated with or without human recombinant IGF-1 (1-100 ng/ml) for 0.5-6 h, to determine phosphorylation of AKT and p70S6K (downstream of mTOR) by Western blot. After 4 days of culture with or without the mTOR inhibitor rapamycin, total protein, DNA, and gene expression were quantified. IGF-1 (100 ng/ml) reduced IGF-1 gene expression, although PFF enhanced IGF-1 expression. IGF-1 did not affect collagen-I gene expression. IGF-1 dose-dependently enhanced AKT and p70S6K phosphorylation at 2 and 6 h. PFF enhanced phosphorylation of AKT and p70S6K already within 1 h. Both IGF-1 and PFF enhanced total protein per cell by ∼30%, but not in the presence of rapamycin. Our results show that IGF-1 and PFF activate mTOR, thereby stimulating the rate of mRNA translation in osteoblasts. The known anabolic effect of mechanical loading and IGF-1 on bone may thus be partly explained by mTOR-mediated enhanced protein synthesis in osteoblasts.

  12. Effect of Diazoxide Preconditioning on Cultured Rat Myocardium Microvascular Endothelial Cells against Apoptosis and Relation of PI3K/Akt Pathway

    OpenAIRE

    Su, Cao; Xia, Tao; Ren, Shen; Qing, She; Jing, Ding; Lian, Huang; Bin, Qin; Yuan, Zhou; Xiang, Zhu

    2014-01-01

    Background: Anti-apoptotic mechanism for cell protection on reperfusion may provide a new method to reduce reperfusion injury. Aims: The aim of the present study is to explore the effect of mitochondrial ATP sensitive potassium channel (Mito-KATP) opener diazoxide (DZ) preconditioning on hypoxia/ reoxygen (H/R) injury of rat myocardium microvascular endothelial cells (MMECs) against apoptosis and relation of PI3K/Akt pathway. Study Design: Animal experimentation. ...

  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. Arctigenin, a Potent Ingredient of Arctium lappa L., Induces Endothelial Nitric Oxide Synthase and Attenuates Subarachnoid Hemorrhage-Induced Vasospasm through PI3K/Akt Pathway in a Rat Model.

    Science.gov (United States)

    Chang, Chih-Zen; Wu, Shu-Chuan; Chang, Chia-Mao; Lin, Chih-Lung; Kwan, Aij-Lie

    2015-01-01

    Upregulation of protein kinase B (PKB, also known as Akt) is observed within the cerebral arteries of subarachnoid hemorrhage (SAH) animals. This study is of interest to examine Arctigenin, a potent antioxidant, on endothelial nitric oxide synthase (eNOS) and Akt pathways in a SAH in vitro study. Basilar arteries (BAs) were obtained to examine phosphatidylinositol-3-kinase (PI3K), phospho-PI3K, Akt, phospho-Akt (Western blot) and morphological examination. Endothelins (ETs) and eNOS evaluation (Western blot and immunostaining) were also determined. Arctigenin treatment significantly alleviates disrupted endothelial cells and tortured internal elastic layer observed in the SAH groups (p Arctigenin (p Arctigenin might exert dural effects in preventing SAH-induced vasospasm through upregulating eNOS expression via the PI3K/Akt signaling pathway and attenuate endothelins after SAH. Arctigenin shows therapeutic promise in the treatment of cerebral vasospasm following SAH. PMID:26539501

  15. Lasiodin inhibits proliferation of human nasopharyngeal carcinoma cells by simultaneous modulation of the Apaf-1/caspase, AKT/MAPK and COX-2/NF-κB signaling pathways.

    Directory of Open Access Journals (Sweden)

    Lianzhu Lin

    Full Text Available Rabdosia serra has been widely used for the treatment of the various human diseases. However, the antiproliferative effects and underlying mechanisms of the compounds in this herb remain largely unknown. In this study, an antiproliferative compound against human nasopharyngeal carcinoma (NPC cells from Rabdosia serra was purified and identified as lasiodin (a diterpenoid. The treatment with lasiodin inhibited cell viability and migration. Lasiodin also mediated the cell morphology change and induced apoptosis in NPC cells. The treatment with lasiodin induced the Apaf-1 expression, triggered the cytochrome-C release, and stimulated the PARP, caspase-3 and caspase-9 cleavages, thereby activating the apoptotic pathways. The treatment with lasiodin also significantly inhibited the phosphorylations of the AKT, ERK1/2, p38 and JNK proteins. The pretreatment with the AKT or MAPK-selective inhibitors considerably blocked the lasiodin-mediated inhibition of cell proliferation. Moreover, the treatment with lasiodin inhibited the COX-2 expression, abrogated NF-κB binding to the COX-2 promoter, and promoted the NF-κB translocation from cell nuclei to cytosol. The pretreatment with a COX-2-selective inhibitor abrogated the lasiodin-induced inhibition of cell proliferation. These results indicated that lasiodin simultaneously activated the Apaf-1/caspase-dependent apoptotic pathways and suppressed the AKT/MAPK and COX-2/NF-κB signaling pathways. This study also suggested that lasiodin could be a promising natural compound for the prevention and treatment of NPC.

  16. Implication of Akt, ERK1/2 and alternative p38MAPK signalling pathways in human colon cancer cell apoptosis induced by green tea EGCG.

    Science.gov (United States)

    Cerezo-Guisado, María Isabel; Zur, Rafal; Lorenzo, María Jesús; Risco, Ana; Martín-Serrano, Miguel A; Alvarez-Barrientos, Alberto; Cuenda, Ana; Centeno, Francisco

    2015-10-01

    We investigated apoptosis induced by the green tea component the epigallocatechin-3-gallate (EGCG) and the pathways underlying its activity in a colon cancer cell line. A complete understanding of the mechanism(s) and molecules targeted by green tea polyphenols could be useful in developing novel therapeutic approaches for cancer treatment. EGCG, which is the major polyphenol in green tea, has cytotoxic effects and induced cell death in HT-29 cell death. In this study, we evaluated the effect EGCG on mitogen-activated protein kinase (MAPK) and Akt pathways. EGCG treatment increased phospho-ERK1/2, -JNK1/2 and -p38α, -p38γ and -p38δ, as well as phospho-Akt levels. Using a combination of kinase inhibitors, we found that EGCG-induced cell death is partially blocked by inhibiting Akt, ERK1/2 or alternative p38MAPK activity. Our data suggest that these kinase pathways are involved in the anti-cancer effects of EGCG and indicate potential use of this compound as chemotherapeutic agent for colon cancer treatment.

  17. MiRNA-199a-3p Regulates C2C12 Myoblast Differentiation through IGF-1/AKT/mTOR Signal Pathway

    Directory of Open Access Journals (Sweden)

    Long Jia

    2013-12-01

    Full Text Available MicroRNAs constitute a class of ~22-nucleotide non-coding RNAs. They modulate gene expression by associating with the 3' untranslated regions (3' UTRs of messenger RNAs (mRNAs. Although multiple miRNAs are known to be regulated during myoblast differentiation, their individual roles in muscle development are still not fully understood. In this study, we showed that miR-199a-3p was highly expressed in skeletal muscle and was induced during C2C12 myoblasts differentiation. We also identified and confirmed several genes of the IGF-1/AKT/mTOR signal pathway, including IGF-1, mTOR, and RPS6KA6, as important cellular targets of miR-199a-3p in myoblasts. Overexpression of miR-199a-3p partially blocked C2C12 myoblast differentiation and the activation of AKT/mTOR signal pathway, while interference of miR-199a-3p by antisense oligonucleotides promoted C2C12 differentiation and myotube hypertrophy. Thus, our studies have established miR-199a-3p as a potential regulator of myogenesis through the suppression of IGF-1/AKT/mTOR signal pathway.

  18. Acute inhibition of PI3K-PDK1-Akt pathway potentiates insulin secretion through upregulation of newcomer granule fusions in pancreatic β-cells.

    Directory of Open Access Journals (Sweden)

    Kyota Aoyagi

    Full Text Available In glucose-induced insulin secretion from pancreatic β-cells, a population of insulin granules fuses with the plasma membrane without the typical docking process (newcomer granule fusions, however, its mechanism is unclear. In this study, we investigated the PI3K signaling pathways involved in the upregulation of newcomer granule fusions. Acute treatment with the class IA-selective PI3K inhibitors, PIK-75 and PI-103, enhanced the glucose-induced insulin secretion. Total internal reflection fluorescent microscopy revealed that the PI3K inhibitors increased the fusion events from newcomer granules. We developed a new system for transfection into pancreatic islets and demonstrated the usefulness of this system in order for evaluating the effect of transfected genes on the glucose-induced secretion in primary cultured pancreatic islets. Using this transfection system together with a series of constitutive active mutants, we showed that the PI3K-3-phosphoinositide dependent kinase-1 (PDK1-Akt pathway mediated the potentiation of insulin secretion. The Akt inhibitor also enhanced the glucose-induced insulin secretion in parallel with the upregulation of newcomer granule fusions, probably via increased motility of intracellular insulin granules. These data suggest that the PI3K-PDK1-Akt pathway plays a significant role in newcomer granule fusions, probably through an alteration of the dynamics of the intracellular insulin granules.

  19. Oleanolic acid supplement attenuates liquid fructose-induced adipose tissue insulin resistance through the insulin receptor substrate-1/phosphatidylinositol 3-kinase/Akt signaling pathway in rats

    International Nuclear Information System (INIS)

    Oleanolic acid, a triterpenoid contained in more than 1620 plants including various fruits and foodstuffs, has numerous metabolic effects, such as hepatoprotection. However, its underlying mechanisms remain poorly understood. Adipose tissue insulin resistance (Adipo-IR) may contribute to the development and progress of metabolic abnormalities through release of excessive free fatty acids from adipose tissue. This study investigated the effect of oleanolic acid on Adipo-IR. The results showed that supplement with oleanolic acid (25 mg/kg, once daily, by oral gavage) over 10 weeks attenuated liquid fructose-induced increase in plasma insulin concentration and the homeostasis model assessment of insulin resistance (HOMA-IR) index in rats. Simultaneously, oleanolic acid reversed the increase in the Adipo-IR index and plasma non-esterified fatty acid concentrations during the oral glucose tolerance test assessment. In white adipose tissue, oleanolic acid enhanced mRNA expression of the genes encoding insulin receptor, insulin receptor substrate (IRS)-1 and phosphatidylinositol 3-kinase. At the protein level, oleanolic acid upregulated total IRS-1 expression, suppressed the increased phosphorylated IRS-1 at serine-307, and restored the increased phosphorylated IRS-1 to total IRS-1 ratio. In contrast, phosphorylated Akt to total Akt ratio was increased. Furthermore, oleanolic acid reversed fructose-induced decrease in phosphorylated-Akt/Akt protein to plasma insulin concentration ratio. However, oleanolic acid did not affect IRS-2 mRNA expression. Therefore, these results suggest that oleanolic acid supplement ameliorates fructose-induced Adipo-IR in rats via the IRS-1/phosphatidylinositol 3-kinase/Akt pathway. Our findings may provide new insights into the mechanisms of metabolic actions of oleanolic acid. - Highlights: • Adipose insulin resistance (Adipo-IR) contributes to metabolic abnormalities. • We investigated the effect of oleanolic acid (OA) on adipo-IR in

  20. Oleanolic acid supplement attenuates liquid fructose-induced adipose tissue insulin resistance through the insulin receptor substrate-1/phosphatidylinositol 3-kinase/Akt signaling pathway in rats

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ying [Faculty of Basic Medical Sciences, Chongqing Medical University, Chongqing 400016 (China); Wang, Jianwei, E-mail: wangjianwei1968@gmail.com [Department of Traditional Chinese Medicine, Chongqing Medical University, Chongqing 400016 (China); Gu, Tieguang [Endocrinology and Metabolism Group, Sydney Institute of Health Sciences, Sydney, NSW 2000 Australia (Australia); Yamahara, Johji [Pharmafood Institute, Kyoto 602-8136 (Japan); Li, Yuhao, E-mail: yuhao@sitcm.edu.au [Endocrinology and Metabolism Group, Sydney Institute of Health Sciences, Sydney, NSW 2000 Australia (Australia)

    2014-06-01

    Oleanolic acid, a triterpenoid contained in more than 1620 plants including various fruits and foodstuffs, has numerous metabolic effects, such as hepatoprotection. However, its underlying mechanisms remain poorly understood. Adipose tissue insulin resistance (Adipo-IR) may contribute to the development and progress of metabolic abnormalities through release of excessive free fatty acids from adipose tissue. This study investigated the effect of oleanolic acid on Adipo-IR. The results showed that supplement with oleanolic acid (25 mg/kg, once daily, by oral gavage) over 10 weeks attenuated liquid fructose-induced increase in plasma insulin concentration and the homeostasis model assessment of insulin resistance (HOMA-IR) index in rats. Simultaneously, oleanolic acid reversed the increase in the Adipo-IR index and plasma non-esterified fatty acid concentrations during the oral glucose tolerance test assessment. In white adipose tissue, oleanolic acid enhanced mRNA expression of the genes encoding insulin receptor, insulin receptor substrate (IRS)-1 and phosphatidylinositol 3-kinase. At the protein level, oleanolic acid upregulated total IRS-1 expression, suppressed the increased phosphorylated IRS-1 at serine-307, and restored the increased phosphorylated IRS-1 to total IRS-1 ratio. In contrast, phosphorylated Akt to total Akt ratio was increased. Furthermore, oleanolic acid reversed fructose-induced decrease in phosphorylated-Akt/Akt protein to plasma insulin concentration ratio. However, oleanolic acid did not affect IRS-2 mRNA expression. Therefore, these results suggest that oleanolic acid supplement ameliorates fructose-induced Adipo-IR in rats via the IRS-1/phosphatidylinositol 3-kinase/Akt pathway. Our findings may provide new insights into the mechanisms of metabolic actions of oleanolic acid. - Highlights: • Adipose insulin resistance (Adipo-IR) contributes to metabolic abnormalities. • We investigated the effect of oleanolic acid (OA) on adipo-IR in

  1. PKC{eta} is a negative regulator of AKT inhibiting the IGF-I induced proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Shahaf, Galit; Rotem-Dai, Noa; Koifman, Gabriela; Raveh-Amit, Hadas; Frost, Sigal A.; Livneh, Etta, E-mail: etta@bgu.ac.il

    2012-04-15

    The PI3K-AKT pathway is frequently activated in human cancers, including breast cancer, and its activation appears to be critical for tumor maintenance. Some malignant cells are dependent on activated AKT for their survival; tumors exhibiting elevated AKT activity show sensitivity to its inhibition, providing an Achilles heel for their treatment. Here we show that the PKC{eta} isoform is a negative regulator of the AKT signaling pathway. The IGF-I induced phosphorylation on Ser473 of AKT was inhibited by the PKC{eta}-induced expression in MCF-7 breast adenocarcinoma cancer cells. This was further confirmed in shRNA PKC{eta}-knocked-down MCF-7 cells, demonstrating elevated phosphorylation on AKT Ser473. While PKC{eta} exhibited negative regulation on AKT phosphorylation it did not alter the IGF-I induced ERK phosphorylation. However, it enhanced ERK phosphorylation when stimulated by PDGF. Moreover, its effects on IGF-I/AKT and PDGF/ERK pathways were in correlation with cell proliferation. We further show that both PKC{eta} and IGF-I confer protection against UV-induced apoptosis and cell death having additive effects. Although the protective effect of IGF-I involved activation of AKT, it was not affected by PKC{eta} expression, suggesting that PKC{eta} acts through a different route to increase cell survival. Hence, our studies show that PKC{eta} provides negative control on AKT pathway leading to reduced cell proliferation, and further suggest that its presence/absence in breast cancer cells will affect cell death, which could be of therapeutic value.

  2. PKCη is a negative regulator of AKT inhibiting the IGF-I induced proliferation

    International Nuclear Information System (INIS)

    The PI3K-AKT pathway is frequently activated in human cancers, including breast cancer, and its activation appears to be critical for tumor maintenance. Some malignant cells are dependent on activated AKT for their survival; tumors exhibiting elevated AKT activity show sensitivity to its inhibition, providing an Achilles heel for their treatment. Here we show that the PKCη isoform is a negative regulator of the AKT signaling pathway. The IGF-I induced phosphorylation on Ser473 of AKT was inhibited by the PKCη-induced expression in MCF-7 breast adenocarcinoma cancer cells. This was further confirmed in shRNA PKCη-knocked-down MCF-7 cells, demonstrating elevated phosphorylation on AKT Ser473. While PKCη exhibited negative regulation on AKT phosphorylation it did not alter the IGF-I induced ERK phosphorylation. However, it enhanced ERK phosphorylation when stimulated by PDGF. Moreover, its effects on IGF-I/AKT and PDGF/ERK pathways were in correlation with cell proliferation. We further show that both PKCη and IGF-I confer protection against UV-induced apoptosis and cell death having additive effects. Although the protective effect of IGF-I involved activation of AKT, it was not affected by PKCη expression, suggesting that PKCη acts through a different route to increase cell survival. Hence, our studies show that PKCη provides negative control on AKT pathway leading to reduced cell proliferation, and further suggest that its presence/absence in breast cancer cells will affect cell death, which could be of therapeutic value.

  3. 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.

  4. Melatonin Modulates Endoplasmic Reticulum Stress and Akt/GSK3-Beta Signaling Pathway in a Rat Model of Renal Warm Ischemia Reperfusion

    Directory of Open Access Journals (Sweden)

    Kaouther Hadj Ayed Tka

    2015-01-01

    Full Text Available Melatonin (Mel is widely used to attenuate ischemia/reperfusion (I/R injury in several organs. Nevertheless, the underlying mechanisms remain unclear. This study was conducted to explore the effect of Mel on endoplasmic reticulum (ER stress, Akt and MAPK cascades after renal warm I/R. Eighteen Wistar rats were randomized into three groups: Sham, I/R, and Mel + I/R. The ischemia period was 60 min followed by 120 min of reperfusion. Mel (10 mg/kg was administrated 30 min prior to ischemia. The creatinine clearance, MDA, LDH levels, and histopathological changes were evaluated. In addition, Western blot was performed to study ER stress and its downstream apoptosis as well as phosphorylation of Akt, GSK-3β, VDAC, ERK, and P38. Mel decreased cytolysis and lipid peroxidation and improved renal function and morphology compared to I/R group. Parallely, it significantly reduced the ER stress parameters including GRP 78, p-PERK, XBP 1, ATF 6, CHOP, and JNK. Simultaneously, p-Akt level was significantly enhanced and its target molecules GSK-3β and VDAC were inhibited. Furthermore, the ERK and P38 phosphorylation were evidently augmented after Mel administration in comparison to I/R group. In conclusion, Mel improves the recovery of renal function by decreasing ER stress and stimulating Akt pathway after renal I/R injury.

  5. Hedyotis diffusa plus Scutellaria barbata Induce Bladder Cancer Cell Apoptosis by Inhibiting Akt Signaling Pathway through Downregulating miR-155 Expression.

    Science.gov (United States)

    Pan, Li-Tao; Sheung, Yip; Guo, Wen-Peng; Rong, Zhi-Bin; Cai, Zhi-Ming

    2016-01-01

    Traditional Chinese medicine is increasingly used to treat cancer. Our clinical experiences identify Hedyotis diffusa plus Scutellaria barbata as the most common herb-pair (couplet medicinal) used for the core treatment of bladder cancer. This study aims to investigate the antitumor effect of the herb-pair in bladder cancer cells. The results show that Hedyotis diffusa plus Scutellaria barbata inhibited bladder cancer cell growth and clone formation in a dose-dependent and time-dependent manner. It also induced cell apoptosis through decreasing Akt activation and reducing the expression of antiapoptotic proteins Bcl-2 and Mcl-1. Further experiments showed that miR-155 was reduced by the herb-pair and miRNA-155 inhibitor induced cell apoptosis and suppressed Akt activation. Overexpression of miR-155 reversed herb-pair induced cell apoptosis through activating Akt pathway in both bladder cancer cell lines. The findings reveal that Hedyotis diffusa plus Scutellaria barbata reduce Akt activation through reducing miR-155 expression, resulting in cell apoptosis. It demonstrated the potential mechanism of Hedyotis diffusa plus Scutellaria barbata for the core treatment of bladder cancer. PMID:26989427

  6. Hedyotis diffusa plus Scutellaria barbata Induce Bladder Cancer Cell Apoptosis by Inhibiting Akt Signaling Pathway through Downregulating miR-155 Expression

    Directory of Open Access Journals (Sweden)

    Li-Tao Pan

    2016-01-01

    Full Text Available Traditional Chinese medicine is increasingly used to treat cancer. Our clinical experiences identify Hedyotis diffusa plus Scutellaria barbata as the most common herb-pair (couplet medicinal used for the core treatment of bladder cancer. This study aims to investigate the antitumor effect of the herb-pair in bladder cancer cells. The results show that Hedyotis diffusa plus Scutellaria barbata inhibited bladder cancer cell growth and clone formation in a dose-dependent and time-dependent manner. It also induced cell apoptosis through decreasing Akt activation and reducing the expression of antiapoptotic proteins Bcl-2 and Mcl-1. Further experiments showed that miR-155 was reduced by the herb-pair and miRNA-155 inhibitor induced cell apoptosis and suppressed Akt activation. Overexpression of miR-155 reversed herb-pair induced cell apoptosis through activating Akt pathway in both bladder cancer cell lines. The findings reveal that Hedyotis diffusa plus Scutellaria barbata reduce Akt activation through reducing miR-155 expression, resulting in cell apoptosis. It demonstrated the potential mechanism of Hedyotis diffusa plus Scutellaria barbata for the core treatment of bladder cancer.

  7. Neuroprotection of Insulin against Oxidative Stress-induced Apoptosis in Cultured Retinal Neurons: Involvement of Phosphoinositide 3-kinase/Akt Signal Pathway

    Institute of Scientific and Technical Information of China (English)

    Xiao-Rui YU; Guo-Rong JIA; Guang-Dao GAO; Shu-Hong WANG; Yan HAN; Wei CAO

    2006-01-01

    In order to investigate the neuroprotection of insulin in retinal neurons, we used retinal neuronal culture as a model system to study the protective effects of insulin against H2O2-induced cytotoxicity and apoptotic death. Primary retinal neuronal cultures were grown from retinas of 0-2-day old Sprague-Dawley rats. Cell viability was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay.Apoptotic cell death was evaluated by the TdT-mediated digoxigenin-dUTP nick-end labeling assay, and by DNA laddering analysis. Phosphoinositide 3-kinase (PI3K) activity was measured using phosphoinositide 4,5-bisphophate and [γ-32p]ATP as substrate. Western blot analysis with anti-phospho-Akt (pS473) antibody was performed to examine the level of phosphorylated Akt. We observed that treatment with 100 μM H2O2 for 24 h significantly decreased cell viability and induced apoptotic death of retinal neurons, and that pretreatment with 10 nM insulin significantly inhibited or attenuated H2O2-induced cytotoxicity and apoptosis. Pretreatment with LY294002, a specific PI3K inhibitor, abolished the cytoprotective effect of insulin. Insulin also strongly activated both PI3K and the downstream effector Akt. These results suggest that insulin protects retinal neurons from oxidative stress-induced apoptosis and that the PI3K/Akt signal pathway is involved in insulinmediated retinal neuroprotection.

  8. PI3k/Akt signalling pathway plays a crucial role in the anti-inflammatory effects of curcumin in LPS-activated microglia.

    Science.gov (United States)

    Cianciulli, Antonia; Calvello, Rosa; Porro, Chiara; Trotta, Teresa; Salvatore, Rosaria; Panaro, Maria Antonietta

    2016-07-01

    Microglia are resident macrophages in the central nervous system (CNS) deputed to defend against pathogens. Persistent or acute inflammation of microglia leads to CNS disorders, so regulation of pro-inflammatory responses of microglial cells is thought to be a promising therapeutic strategy to attenuate abnormal inflammatory responses observed in neurodegenerative disease. We hypothesized that curcumin supplementation could reduce the inflammatory responses of activated microglial cells modulating PI3K/Akt pathway. Different curcumin concentrations were administered as BV-2 microglia pre-treatment 1h prior to LPS stimulation. Nitric oxide (NO) and inducible nitric oxide synthase (iNOS) expression were determined by Griess reagent and western blotting, respectively. Inflammatory cytokines release was evaluated by ELISA and qRT-PCR. PI3K/Akt expression was analyzed by western blotting analysis. Curcumin significantly attenuated, in a dose-dependent manner, LPS-induced release of NO and pro-inflammatory cytokines, as well as iNOS expression. Interestingly, curcumin was able to reduce, again in a dose-dependent manner, PI3K/Akt phosphorylation as well as NF-κB activation in LPS-activated microglial cells. Overall these results suggest that curcumin plays an important role in the attenuation of LPS-induced inflammatory responses in microglial cells and that the mechanisms involve down-regulation of the PI3K/Akt signalling. PMID:27208432

  9. FAK Mediates a Compensatory Survival Signal Parallel to PI3K-AKT in PTEN-Null T-ALL Cells

    Directory of Open Access Journals (Sweden)

    Dewen You

    2015-03-01

    Full Text Available Mutations and inactivation of phosphatase and tensin homolog deleted from chromosome 10 (PTEN are observed in 15%–25% of cases of human T cell acute lymphoblastic leukemia (T-ALL. Pten deletion induces myeloproliferative disorders (MPDs, acute myeloid leukemia (AML, and/or T-ALL in mice. Previous studies attributed Pten-loss-related hematopoietic defects and leukemogenesis to excessive activation of phosphatidylinositol 3-kinase (PI3K/AKT/mTOR signaling. Although inhibition of this signal dramatically suppresses the growth of PTEN-null T-ALL cells in vitro, treatment with inhibitors of this pathway does not cause a complete remission in vivo. Here, we report that focal adhesion kinase (Fak, a protein substrate of Pten, also contributes to T-ALL development in Pten-null mice. Inactivation of the FAK signaling pathway by either genetic or pharmacologic methods significantly sensitizes both murine and human PTEN-null T-ALL cells to PI3K/AKT/mTOR inhibition when cultured in vitro on feeder layer cells or a matrix and in vivo.

  10. FAK mediates a compensatory survival signal parallel to PI3K-AKT in PTEN-null T-ALL cells.

    Science.gov (United States)

    You, Dewen; Xin, Junping; Volk, Andrew; Wei, Wei; Schmidt, Rachel; Scurti, Gina; Nand, Sucha; Breuer, Eun-Kyoung; Kuo, Paul C; Breslin, Peter; Kini, Ameet R; Nishimura, Michael I; Zeleznik-Le, Nancy J; Zhang, Jiwang

    2015-03-31

    Mutations and inactivation of phosphatase and tensin homolog deleted from chromosome 10 (PTEN) are observed in 15%-25% of cases of human T cell acute lymphoblastic leukemia (T-ALL). Pten deletion induces myeloproliferative disorders (MPDs), acute myeloid leukemia (AML), and/or T-ALL in mice. Previous studies attributed Pten-loss-related hematopoietic defects and leukemogenesis to excessive activation of phosphatidylinositol 3-kinase (PI3K)/AKT/mTOR signaling. Although inhibition of this signal dramatically suppresses the growth of PTEN-null T-ALL cells in vitro, treatment with inhibitors of this pathway does not cause a complete remission in vivo. Here, we report that focal adhesion kinase (Fak), a protein substrate of Pten, also contributes to T-ALL development in Pten-null mice. Inactivation of the FAK signaling pathway by either genetic or pharmacologic methods significantly sensitizes both murine and human PTEN-null T-ALL cells to PI3K/AKT/mTOR inhibition when cultured in vitro on feeder layer cells or a matrix and in vivo. PMID:25801032

  11. Akt inhibition up-regulates MMP1 through a CCN2-dependent pathway in human dermal fibroblasts

    OpenAIRE

    Bujor, Andreea M.; Nakerakanti, Sashidar; Morris, Erin; Hant, Faye N; Trojanowska, Maria

    2010-01-01

    Akt is a key signalling molecule that was found to be down-regulated in chronic wounds. Akt blockade has dual antifibrotic effects in human dermal fibroblasts, by up-regulating matrix metalloproteinase 1 (MMP1) and down-regulating collagen gene expression (J Invest Dermatol 2008: 128: 1906). The aim of this study was to gain additional insights into the mechanism of MMP1 up-regulation following Akt blockade. As previous studies showed that CCN2 can be a positive regulator of MMP1, we examined...

  12. Modulation of Akt and ERK1/2 pathways by resveratrol in chronic myelogenous leukemia (CML cells results in the downregulation of Hsp70.

    Directory of Open Access Journals (Sweden)

    Soumyajit Banerjee Mustafi

    Full Text Available BACKGROUND: Resveratrol is known to downregulate the high endogenous level of Heat shock protein 70 (Hsp70 in Chronic Myelogenous Leukemia (CML K562 cells and induce apoptosis. Since Heat Shock Factor 1 (HSF1 controls transcription of Hsp70, we wanted to probe the signaling pathways responsible for transcriptional activation of HSF1. METHODOLOGY/PRINCIPAL FINDINGS: Cells exposed to 40microM Resveratrol rapidly abolished serine473 phosphorylation of Akt and significantly reduced its kinase activity. Inactivation of Akt pathway by Resveratrol subsequently blocked serine9 phosphorylation of Gsk3beta. Active non-phosphorylated Gsk3beta rendered HSF1 transcriptionally inactive and reduced Hsp70 production. Blocking PI3K/Akt activity also demonstrated similar effects on Hsp70 comparable to Resveratrol. Inactivation of Gsk3beta activity by inhibitors SB261763 or LiCl upregulated Hsp70. Resveratrol significantly modulated ERK1/2 activity as evident from hyper phosphorylation at T302/Y304 residues and simultaneous upregulation in kinase activity. Blocking ERK1/2 activation resulted in induction of Hsp70. Therefore, increase in ERK1/2 activity by Resveratrol provided another negative influence on Hsp70 levels through negative regulation of HSF1 activity. 17-allylamino-17-demethoxygeldanamycin (17AAG, a drug that inhibits Hsp90 chaperone and degrades its client protein Akt concomitantly elevated Hsp70 levels by promoting nuclear translocation of HSF1 from the cytosol. This effect is predominantly due to inhibition of both Akt and ERK1/2 activation by 17AAG. Simultaneously treating K562 with Resveratrol and 17AAG maintained phosho-ERK1/2 levels close to untreated controls demonstrating their opposite effects on ERK1/2 pathway. Resveratrol was found not to interfere with Bcr-Abl activation in K562 cells. CONCLUSION/SIGNIFICANCE: Thus our study comprehensively illustrates that Resveratrol acts downstream of Bcr-Abl and inhibits Akt activity but stimulates ERK

  13. EGF‑stimulated AKT activation is mediated by EGFR recycling via an early endocytic pathway in a gefitinib‑resistant human lung cancer cell line.

    Science.gov (United States)

    Nishimura, Yukio; Takiguchi, Soichi; Ito, Shigeru; Itoh, Kazuyuki

    2015-04-01

    The receptor tyrosine kinase epidermal growth factor receptor (EGFR) and its ligand epidermal growth factor (EGF) are known to play important roles in malignant tumor cells, and the EGFR signaling pathway is one of the most important targets in various tumors, including non-small cell lung cancer (NSCLC). We reported recently that an aberration in certain steps of EGF-stimulated phosphorylated epidermal growth factor receptor (pEGFR) endocytic trafficking from the early endosomes to the late endosomes occurs in the gefitinib-resistant NSCLC cells, in which large amounts of sorting nexin 1 (SNX1) are colocalized with EGFR in the aggregated early endosomes where the internalized pEGFR is also accumulated of these cells. To further investigate the role of SNX1 in EGF‑stimulated pEGFR endocytosis, followed by downstream signaling leading to the activation of phosphatidylinositol 3-kinase (PI3K)--the serine/threonine kinase AKT pathway, we examined the effect of depletion of SNX1 knock-down expression by siRNA and an inhibition of targeting membrane recycling using monensin. Using immunofluorescence, we observed an efficient endocytic transport of pEGFR from early endosomes to late endosomes/lysosomes after EGF-stimulation in the cells transfected with siRNA‑SNX1, whereas the delayed endocytic delivery of pEGFR was evident in the siRNA-control-transfected cells. Furthermore, a large amount of endocytosed pEGFR was accumulated in the presence of monensin in the early endosomes of the SNX1 knock-down cells. In western blot analysis, EGF stimulation of both control and cells transfected with siRNA-SNX1 resulted in rapid phosphorylation of EGFR and enhanced AKT phosphorylation. Monensin-dependent inhibition of AKT phosphorylation was stronger in SNX1 knock-down cells than in controls. In contrast, however, monensin had no effect on AKT phosphorylation triggered by activation of the MET receptor tyrosine kinase. Collectively, we suggest that EGF-stimulated recycling of

  14. The modulation of vascular ATP-sensitive K+ channel function via the phosphatidylinositol 3-kinase-Akt pathway activated by phenylephrine.

    Science.gov (United States)

    Haba, Masanori; Hatakeyama, Noboru; Kinoshita, Hiroyuki; Teramae, Hiroki; Azma, Toshiharu; Hatano, Yoshio; Matsuda, Naoyuki

    2010-08-01

    The present study examined the modulator role of the phosphatidylinositol 3-kinase (PI3K)-Akt pathway activated by the alpha-1 adrenoceptor agonist phenylephrine in ATP-sensitive K(+) channel function in intact vascular smooth muscle. We evaluated the ATP-sensitive K(+) channel function and the activity of the PI3K-Akt pathway in the rat thoracic aorta without endothelium. The PI3K inhibitor 2-(4-morpholinyl)-8-phenyl-1(4H)-benzopyran-4-one hydrochloride (LY294002) (10(-5) M) augmented relaxation in response to the ATP-sensitive K(+) channel opener levcromakalim (10(-8) to 3 x 10(-6) M) in aortic rings contracted with phenylephrine (3 x 10(-7) M) but not with 9,11-dideoxy-11alpha,9alpha-epoxy-methanoprostaglandin F(2alpha) (U46619; 3 x 10(-8) M), although those agents induced similar contraction. ATP-sensitive K(+) channel currents induced by levcromakalim (10(-6) M) in the presence of phenylephrine (3 x 10(-7) M) were enhanced by the nonselective alpha-adrenoceptor antagonist phentolamine (10(-7) M) and LY294002 (10(-5) M). Levels of the regulatory subunits of PI3K p85-alpha and p55-gamma increased in the membrane fraction from aortas without endothelium treated with phenylephrine (3 x 10(-7) M) but not with U46619 (3 x 10(-8) M). Phenylephrine simultaneously augmented Akt phosphorylation at Ser473 and Thr308. Therefore, activation of the PI3K-Akt pathway seems to play a role in the impairment of ATP-sensitive K(+) channel function in vascular smooth muscle exposed to alpha-1 adrenergic stimuli.

  15. 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.

  16. 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. PMID:27197306

  17. Liraglutide Exerts Antidiabetic Effect via PTP1B and PI3K/Akt2 Signaling Pathway in Skeletal Muscle of KKAy Mice

    Directory of Open Access Journals (Sweden)

    Wenjun Ji

    2014-01-01

    Full Text Available Background. Liraglutide (a glucagon-like peptide 1 analog was used for the treatment of type 2 diabetes (T2DM which could produce glucose-dependent insulin secretion. Aim. The aim was to investigate whether liraglutide could improve myofibril and mitochondria injury in skeletal muscle and the mechanisms in diabetic KKAy mice. Method. We divided the male KKAy mice into 2 groups: liraglutide group (250 μg/kg/day liraglutide subcutaneous injection and model group; meanwhile, the male C57BL/6J mice were considered as the control. After 6 weeks, the ultrastructure of skeletal muscle was observed by electron microscope. The gene expressions of protein tyrosine phosphatase 1B (PTP1B, phosphatidylinositol 3-kinase (PI3K, and glucose transporter type 4 (GLUT4 were determined by real-time PCR. The protein levels of the above molecules and phospho-Akt2 (p-Akt2 were measured by Western blot. Results. Liraglutide significantly ameliorated the injury of mitochondria by increasing the number (+441% and the area (+113% of mitochondria and mitochondrial area/100 µm2 (+396% in skeletal muscle of KKAy mice. The results of real-time PCR and Western blot showed that liraglutide downregulated PTP1B while it upregulated PI3K and GLUT4 (P<0.01. The protein level of p-Akt2/Akt2 was also increased (P<0.01. Conclusion. These results revealed that liraglutide could improve myofibril and mitochondria injury in skeletal muscle against T2DM via PTP1B and PI3K/Akt2 signaling pathway.

  18. Low Amount of Salinomycin Greatly Increases Akt Activation, but Reduces Activated p70S6K Levels

    Directory of Open Access Journals (Sweden)

    Sungpil Yoon

    2013-08-01

    Full Text Available The present study identified a novel salinomycin (Sal-sensitization mechanism in cancer cells. We analyzed the signal proteins Akt, Jnk, p38, Jak, and Erk1/2 in cancer cell lines that had arrested growth following low amounts of Sal treatment. We also tested the signal molecules PI3K, PDK1, GSK3β, p70S6K, mTOR, and PTEN to analyze the PI3K/Akt/mTOR pathway. The results showed that Sal sensitization positively correlates with large reductions in p70S6K activation. Interestingly, Akt was the only signal protein to be significantly activated by Sal treatment. The Akt activation appeared to require the PI3K pathway as its activation was abolished by the PI3K inhibitors LY294002 and wortmannin. The Akt activation by Sal was conserved in the other cell lines analyzed, which originated from other organs. Both Akt activation and C-PARP production were proportionally increased with increased doses of Sal. In addition, the increased levels of pAkt were not reduced over the time course of the experiment. Co-treatment with Akt inhibitors sensitized the Sal-treated cancer cells. The results thereby suggest that Akt activation is increased in cells that survive Sal treatment and resist the cytotoxic effect of Sal. Taken together; these results indicate that Akt activation may promote the resistance of cancer cells to Sal.

  19. 3-Bromopyruvate induces apoptosis in breast cancer cells by downregulating Mcl-1 through the PI3K/Akt signaling pathway.

    Science.gov (United States)

    Liu, Zhe; Zhang, Yuan-Yuan; Zhang, Qian-Wen; Zhao, Su-Rong; Wu, Cheng-Zhu; Cheng, Xiu; Jiang, Chen-Chen; Jiang, Zhi-Wen; Liu, Hao

    2014-04-01

    The hexokinase inhibitor 3-bromopyruvate (3-BrPA) can inhibit glycolysis in tumor cells to reduce ATP production, resulting in apoptosis. However, as 3-BrPA is an alkylating agent, its cytotoxic action may be induced by other molecular mechanisms. The results presented here reveal that 3-BrPA-induced apoptosis is caspase independent. Further, 3-BrPA induces the generation of reactive oxygen species in MDA-MB-231 cells, leading to mitochondria-mediated apoptosis. These results suggest that caspase-independent apoptosis may be induced by the generation of reactive oxygen species. In this study, we also demonstrated that 3-BrPA induces apoptosis through the downregulation of myeloid cell leukemia-1 (Mcl-1) in MDA-MB-231 breast cancer cells. The results of Mcl-1 knockdown indicate that Mcl-1 plays an important role in 3-BrPA-induced apoptosis. Further, the upregulation of Mcl-1 expression in 3-BrPA-treated MDA-MB-231 cells significantly increases cell viability. In addition, 3-BrPA treatment resulted in the downregulation of p-Akt, suggesting that 3-BrPA may downregulate Mcl-1 through the phosphoinositide-3-kinase/Akt pathway. These findings indicate that 3-BrPA induces apoptosis in breast cancer cells by downregulating Mcl-1 through the phosphoinositide-3-kinase/Akt signaling pathway. PMID:24492287

  20. RLIP76-dependent suppression of PI3K/AKT/Bcl-2 pathway by miR-101 induces apoptosis in prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jing; Song, Qi; Cai, Yi; Wang, Peng; Wang, Min; Zhang, Dong, E-mail: zhangd1117@yahoo.com

    2015-08-07

    MicroRNA-101 (miR-101) participates in carcinogenesis and tumor progression in various cancers. However, its biological functions in prostate cancer are still unclear. Here, we demonstrate that miR-101 represents a critical role in regulating cell apoptosis in prostate cancer cells. We first demonstrated that miR-101 treatment promoted apoptosis in DU145 and PC3 cells by using flow cytometric analysis and transmission electron microscopy (TEM). To verify the mechanisms, we identified a novel miR-101 target, Ral binding protein 1 (RLIP76). We found miR-101 transfection significantly suppresses RLIP76 expression, which can transactivate phosphorylation of PI3K-Akt signaling, and resulted in an amplification of Bcl2-induced apoptosis. Furthermore, we demonstrated that RLIP76 overexpression could reverse the anti-tumor effects of miR-101 in DU145 and PC3 cells by using flow cytometry assay and MTT assay. Taken together, our results revealed that the effect of miR-101 on prostate cancer cell apoptosis was due to RLIP76 regulation of the PI3K/Akt/Bcl-2 signaling pathway. - Highlights: • miR-101 inhibited prostate cancer cell proliferation and enhanced apoptosis. • miR-101 directly targeted and regulated RLIP76 expression. • miR-101 suppressed PI3K/Akt/Bcl-2 signaling pathway by targeting RLIP76.

  1. RLIP76-dependent suppression of PI3K/AKT/Bcl-2 pathway by miR-101 induces apoptosis in prostate cancer

    International Nuclear Information System (INIS)

    MicroRNA-101 (miR-101) participates in carcinogenesis and tumor progression in various cancers. However, its biological functions in prostate cancer are still unclear. Here, we demonstrate that miR-101 represents a critical role in regulating cell apoptosis in prostate cancer cells. We first demonstrated that miR-101 treatment promoted apoptosis in DU145 and PC3 cells by using flow cytometric analysis and transmission electron microscopy (TEM). To verify the mechanisms, we identified a novel miR-101 target, Ral binding protein 1 (RLIP76). We found miR-101 transfection significantly suppresses RLIP76 expression, which can transactivate phosphorylation of PI3K-Akt signaling, and resulted in an amplification of Bcl2-induced apoptosis. Furthermore, we demonstrated that RLIP76 overexpression could reverse the anti-tumor effects of miR-101 in DU145 and PC3 cells by using flow cytometry assay and MTT assay. Taken together, our results revealed that the effect of miR-101 on prostate cancer cell apoptosis was due to RLIP76 regulation of the PI3K/Akt/Bcl-2 signaling pathway. - Highlights: • miR-101 inhibited prostate cancer cell proliferation and enhanced apoptosis. • miR-101 directly targeted and regulated RLIP76 expression. • miR-101 suppressed PI3K/Akt/Bcl-2 signaling pathway by targeting RLIP76

  2. α-Mangostin Suppresses the Viability and Epithelial-Mesenchymal Transition of Pancreatic Cancer Cells by Downregulating the PI3K/Akt Pathway

    Directory of Open Access Journals (Sweden)

    Qinhong Xu

    2014-01-01

    Full Text Available α-Mangostin, a natural product isolated from the pericarp of the mangosteen fruit, has been shown to inhibit the growth of tumor cells in various types of cancers. However, the underlying molecular mechanisms are largely unclear. Here, we report that α-mangostin suppressed the viability and epithelial-mesenchymal transition (EMT of pancreatic cancer cells through inhibition of the PI3K/Akt pathway. Treatment of pancreatic cancer BxPc-3 and Panc-1 cells with α-mangostin resulted in loss of cell viability, accompanied by enhanced cell apoptosis, cell cycle arrest at G1 phase, and decrease of cyclin-D1. Moreover, Transwell and Matrigel invasion assays showed that α-mangostin significantly reduced the migration and invasion of pancreatic cancer cells. Consistent with these results, α-mangostin decreased the expression of MMP-2, MMP-9, N-cadherin, and vimentin and increased the expression of E-cadherin. Furthermore, we found that α-mangostin suppressed the activity of the PI3K/Akt pathway in pancreatic cancer cells as demonstrated by the reduction of the Akt phosphorylation by α-mangostin. Finally, α-mangostin significantly inhibited the growth of BxPc-3 tumor mouse xenografts. Our results suggest that α-mangostin may be potentially used as a novel adjuvant therapy or complementary alternative medicine for the management of pancreatic cancers.

  3. Picropodophyllin inhibits the growth of Ewing's sarcoma cells through the insulin‑like growth factor‑1 receptor/Akt signaling pathway.

    Science.gov (United States)

    Wu, Yong-Tao; Wang, Bao-Jun; Miao, Sheng-Wu; Gao, Jian-Jun

    2015-11-01

    Ewing's sarcoma (ES) is the second most common type of pediatric bone tumor, and is associated with a poor prognosis. Picropodophyllin (PPP), a novel selective inhibitor of insulin‑like growth factor‑1 receptor (IGF‑1R), is able to strongly inhibit various types of cancers. However, the effect of IGF‑1R on ES remains unclear. Following treatment with various concentrations of PPP for various times, cell viability was determined using an MTT assay. In addition, cell proliferation and apoptosis was investigated separately by bromodeoxyuridine staining and flow cytometry, respectively. The PPP‑associated signaling pathway was also investigated. The results of the present study suggested that PPP inhibited cell proliferation and viability of A673 and SK‑ES‑1 human Ewing's sarcoma cells in a dose- and time‑dependent manner. In addition, cell apoptosis rates were increased following treatment with PPP. Further investigation of the underlying mechanism revealed that PPP inhibited Akt phosphorylation. Fumonisin B1, an Akt‑specific activator, reversed the inhibitory effects of PPP on cell growth. Furthermore, the results suggested that PPP decreased the expression levels of IGF‑1R, a common activator of Akt signaling. PPP inhibited the growth of human Ewing's sarcoma cells by targeting the IGF‑1R/Akt signaling pathway. Therefore, PPP may prove useful in the development of an effective strategy for the treatment of Ewing's sarcoma.

  4. Histone deacetylase inhibitor reverses multidrug resistance by attenuating the nucleophosmin level through PI3K/Akt pathway in breast cancer.

    Science.gov (United States)

    Chen, Si-Ying; Zheng, Xiao-Wei; Cai, Jiang-Xia; Zhang, Wei-Peng; You, Hai-Sheng; Xing, Jian-Feng; Dong, Ya-Lin

    2016-07-01

    The development of multidrug resistance (MDR) is the major obstacle in the chemotherapy of breast cancer, and it restricts the application of antitumor drugs in the clinic. Therefore it is urgent to search for ways to reverse MDR and restore sensitivity to chemotherapeutics in breast carcinoma. Currently, histone deacetylase inhibitors (HDACIs) offer a promising strategy for tumor therapy as the effective anticancer drugs. Based on the potential resistant target of nucleophosmin (NPM), the purpose of this study was to explore the reversal effect of a new synthetic histone deacetylase inhibitor, FA17, on MDR in methotrexate-resistant breast cancer cells (MCF-7/MTX) and xenograft tumors. It was shown that the abnormal expression of NPM induced MDR and inhibited downstream mitochondrial apoptotic pathway by activating PI3K/Akt signaling pathway in MCF-7/MTX cells. The reversal effect and molecular mechanism of FA17 were investigated both in vitro and in vivo. We found that FA17 could significantly reverse resistance and sensitize MCF-7/MTX cells to methotrexate. FA17 obviously enhanced resistant cell apoptosis, inhibited expressions of NPM and efflux transporters. Additionally, FA17 could reverse MDR via inactivating PI3K/Akt pathway and accelerating mitochondrial apoptotic pathway both in MCF-7/MTX cells and in xenograft tumors. Taken together, the novel histone deacetylase inhibitor could effectively reverse drug resistance due to suppressing the activity of NPM and drug efflux pumps by PI3K/Akt and mitochondrial apoptotic pathway. The above not only indicated the potential applied value of FA17 in reversing MDR and enhancing the sensitivity of chemotherapy, but also confirmed the role of NPM in the development of MDR in breast cancer. PMID:27211281

  5. Cisplatin Induces Overactivation of the Dormant Primordial Follicle through PTEN/AKT/FOXO3a Pathway which Leads to Loss of Ovarian Reserve in Mice.

    Directory of Open Access Journals (Sweden)

    Eun Mi Chang

    Full Text Available Cisplatin is a first-line chemotherapeutic agent for ovarian cancer that acts by promoting DNA cross links and adduct. However drug resistance and considerable side effects including reproductive toxicity remain a significant challenge. PTEN is well known as a tumor suppressor function which plays a fundamental role in the regulation of the cell cycle, apoptosis and development of cancer. At the same time PTEN has been revealed to be critically important for the maintenance of the primordial follicle pool. In this study, we investigated the role of PTEN/Akt/FOXO3 pathway in cisplatin-induced primordial follicle depletion. Cisplatin induced ovarian failure mouse model was used to evaluate how this pathway involves. In vitro maturation was used for oocyte rescue after cisplatin damage. We found that cisplatin treatment decreased PTEN levels, leading to a subsequent increase in the phosphorylation of key molecules in the pathway. The activation of the PTEN/Akt/FOXO3 pathway cascade increased cytoplasmic translocation of FOXO3a in cisplatin-treated follicles, which in turn increased the pool size of growing follicles, and rapidly depleted the number of dormant follicles. Once activated, the follicles were more prone to apoptosis, and their cumulus cells showed a loss of luteinizing hormone (LH receptor expression, which leads to failure during final maturation and ovulation. In vitro maturation to rescue oocytes in a cisplatin-treated mouse model resulted in successful maturation and fertilization. This study is the first to show the involvement of the PTEN/Akt/FOXO3 pathway in premature ovarian failure after cisplatin treatment and the possibility of rescue through in vitro maturation.

  6. Prosaposin ablation inactivates the MAPK and Akt signaling pathways and interferes with the development of the prostate gland

    Institute of Scientific and Technical Information of China (English)

    CarlosR.Morales; HaithamBadran

    2003-01-01

    The recent development of a prosaposin-/-mouse model has allowed the investigation of the role of prosaposin in the development of the male reproductive organs.A morphometric analysis of the male reproductive system of 37 days old mice revealed that prosaposin ablation produced a 30% reduction in size and weight of the testes,37% of the epididymis,75% of the seminal vesicles and 60% of the prostate glands.Light microscopy(LM) showed that smaller testis size from homozygous mutant mice was associated with reduced spermiogenesis.Both,dorsal and ventral lobules of the prostate glands were underdeveloped in the homozygous mutant.LM analysis also showed that prostatic alveoli were considerably smaller and lined by shorter epithelial cells in the homozygous mutant.Smaller tubular diameter and shorter undifferentiated epithelial cells were also observed in seminal vesicles and epididymis. In the efferent ducts of the homozygous mutant mice,the epithelium was composed exclusively of ciliated cells in contrast to the heterozygotes,which showed the presence of nonciliated cells.Radioimmunoassays demonstratedthat testosterone levels were normal or higher in mice with the inactivated prosaposin gene.Immunostaining of prostate sections with an anti-androgen receptor antibody showed that the epithelial cells lining the alveoli express androgen receptor in both the heterozygous and homozygous tissue.Similarly,sections immunostained with antibodies to the phosphorylated MAPKs and Akts strongly reacted with tall prostatic secretory cells in prostate from heterozygous mouse.On the other hand,the epithelial cells in the homozygous prostate remained unstained or weakly stained.These findings demonstrate that inactivation of the prosaposin gene affected the development of the prostate gland and some components of the MAP pathway.

  7. Cancer pathways are associated with improved long-term survival

    DEFF Research Database (Denmark)

    Jensen, Kenneth Højsgaard; Maina, Pierre Jean-Claude

    2015-01-01

    (n = 161) to 72.6% in the CPP group operated after 1 April (p = 0.026). Using the Cox regression model, we found that CPP was an independent factor associated with survival (p = 0.032, hazard ratio = 0.661, 95% confidence interval: 0.454-0.964). CONCLUSION: Introduction of CCPs in a single centre...... was associated with a significant improvement of overall sur-vival, and using Cox regression we found that the CPP was an independent marker for survival. Larger studies are needed to clearly understand the effect of CPP. FUNDING: not relevant. TRIAL REGISTRATION: not relevant....

  8. Protein S blocks the extrinsic apoptotic cascade in tissue plasminogen activator/N-methyl D-aspartate-treated neurons via Tyro3-Akt-FKHRL1 signaling pathway

    Directory of Open Access Journals (Sweden)

    Freeman Robert S

    2011-02-01

    Full Text Available Abstract Background Thrombolytic therapy with tissue plasminogen activator (tPA benefits patients with acute ischemic stroke. However, tPA increases the risk for intracerebral bleeding and enhances post-ischemic neuronal injury if administered 3-4 hours after stroke. Therefore, combination therapies with tPA and neuroprotective agents have been considered to increase tPA's therapeutic window and reduce toxicity. The anticoagulant factor protein S (PS protects neurons from hypoxic/ischemic injury. PS also inhibits N-methyl-D-aspartate (NMDA excitotoxicity by phosphorylating Bad and Mdm2 which blocks the downstream steps in the intrinsic apoptotic cascade. To test whether PS can protect neurons from tPA toxicity we studied its effects on tPA/NMDA combined injury which in contrast to NMDA alone kills neurons by activating the extrinsic apoptotic pathway. Neither Bad nor Mdm2 which are PS's targets and control the intrinsic apoptotic pathway can influence the extrinsic cascade. Thus, based on published data one cannot predict whether PS can protect neurons from tPA/NMDA injury by blocking the extrinsic pathway. Neurons express all three TAM (Tyro3, Axl, Mer receptors that can potentially interact with PS. Therefore, we studied whether PS can activate TAM receptors during a tPA/NMDA insult. Results We show that PS protects neurons from tPA/NMDA-induced apoptosis by suppressing Fas-ligand (FasL production and FasL-dependent caspase-8 activation within the extrinsic apoptotic pathway. By transducing neurons with adenoviral vectors expressing the kinase-deficient Akt mutant AktK179A and a triple FKHRL1 Akt phosphorylation site mutant (FKHRL1-TM, we show that Akt activation and Akt-mediated phosphorylation of FKHRL1, a member of the Forkhead family of transcription factors, are critical for FasL down-regulation and caspase-8 inhibition. Using cultured neurons from Tyro3, Axl and Mer mutants, we show that Tyro3, but not Axl and Mer, mediates

  9. Anti-diabetic effect of citrus pectin in diabetic rats and potential mechanism via PI3K/Akt signaling pathway.

    Science.gov (United States)

    Liu, Yanlong; Dong, Man; Yang, Ziyu; Pan, Siyi

    2016-08-01

    This study was performed to investigate the anti-diabetic effect of citrus pectin in type 2 diabetic rats and its potential mechanism of action. The results showed that fasting blood glucose levels were significantly decreased after 4 weeks of citrus pectin administration. Citrus pectin improved glucose tolerance, hepatic glycogen content and blood lipid levels (TG, TC, LDL-c and HDL-c) in diabetic rats. Citrus pectin also significantly reduced insulin resistance, which played an important role in the resulting anti-diabetic effect. Moreover, after the pectin treatment, phosphorylated Akt expression was upregulated and GSK3β expression was downregulated, indicating that the potential anti-diabetic mechanism of citrus pectin might occur through regulation of the PI3K/Akt signaling pathway. Together, these results suggested that citrus pectin could ameliorate type 2 diabetes and potentially be used as an adjuvant treatment.

  10. Carvacrol Alleviates Prostate Cancer Cell Proliferation, Migration, and Invasion through Regulation of PI3K/Akt and MAPK Signaling Pathways

    Science.gov (United States)

    Luo, Yun; Wu, Jie-Ying; Lu, Min-Hua; Shi, Zhi

    2016-01-01

    TRPM7 is a potential therapeutic target for treatment of prostate cancer. In this study, we investigated the effects of nonselective TRPM7 inhibitor carvacrol on cell proliferation, migration, and invasion of prostate cancer PC-3 and DU145 cells. Our results showed that carvacrol blocked TRPM7-like currents in PC-3 and DU145 cells and reduced their proliferation, migration, and invasion. Moreover, carvacrol treatment significantly decreased MMP-2, p-Akt, and p-ERK1/2 protein expression and inhibited F-actin reorganization. Furthermore, consistently, TRPM7 knockdown reduced prostate cancer cell proliferation, migration, and invasion as well. Our study suggests that carvacrol may have therapeutic potential for the treatment of prostate cancer through its inhibition of TRPM7 channels and suppression of PI3K/Akt and MAPK signaling pathways. PMID:27803760

  11. Upregulation of PTEN in glioma cells by cord blood mesenchymal stem cells inhibits migration via downregulation of the PI3K/Akt pathway.

    Directory of Open Access Journals (Sweden)

    Venkata Ramesh Dasari

    Full Text Available BACKGROUND: PTEN (phosphatase and tensin homologue deleted on chromosome ten is a tumor suppressor gene implicated in a wide variety of human cancers, including glioblastoma. PTEN is a major negative regulator of the PI3K/Akt signaling pathway. Most human gliomas show high levels of activated Akt, whereas less than half of these tumors carry PTEN mutations or homozygous deletions. The unique ability of mesenchymal stem cells to track down tumor cells makes them as potential therapeutic agents. Based on this capability, new therapeutic approaches have been developed using mesenchymal stem cells to cure glioblastoma. However, molecular mechanisms of interactions between glioma cells and stem cells are still unknown. METHODOLOGY/PRINCIPAL FINDINGS: In order to study the mechanisms by which migration of glioma cells can be inhibited by the upregulation of the PTEN gene, we studied two glioma cell lines (SNB19 and U251 and two glioma xenograft cell lines (4910 and 5310 alone and in co-culture with human umbilical cord blood-derived mesenchymal stem cells (hUCBSC. Co-cultures of glioma cells showed increased expression of PTEN as evaluated by immunofluorescence and immunoblotting assays. Upregulation of PTEN gene is correlated with the downregulation of many genes including Akt, JUN, MAPK14, PDK2, PI3K, PTK2, RAS and RAF1 as revealed by cDNA microarray analysis. These results have been confirmed by reverse-transcription based PCR analysis of PTEN and Akt genes. Upregulation of PTEN resulted in the inhibition of migration capability of glioma cells under in vitro conditions. Also, wound healing capability of glioma cells was significantly inhibited in co-culture with hUCBSC. Under in vivo conditions, intracranial tumor growth was inhibited by hUCBSC in nude mice. Further, hUCBSC upregulated PTEN and decreased the levels of XIAP and Akt, which are responsible for the inhibition of tumor growth in the mouse brain. CONCLUSIONS/SIGNIFICANCE: Our studies

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

    Science.gov (United States)

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

    2016-09-01

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

  13. Insulin and insulin-like growth factor-1 can modulate the phosphoinositide-3-kinase/Akt/FoxO1 pathway in SZ95 sebocytes in vitro.

    Science.gov (United States)

    Mirdamadi, Yasaman; Thielitz, Anja; Wiede, Antje; Goihl, Alexander; Papakonstantinou, Eleni; Hartig, Roland; Zouboulis, Christos C; Reinhold, Dirk; Simeoni, Luca; Bommhardt, Ursula; Quist, Sven; Gollnick, Harald

    2015-11-01

    A recent hypothesis suggests that a high glycaemic load diet-associated increase of insulin-like growth factor-1 (IGF-1) and insulin may promote acne by reducing nuclear localization of the forkhead box-O1 (FoxO1) transcription factor via activation of the phosphoinositide-3-kinase (PI3K)/Akt pathway. Using SZ95 sebocytes as a model, we investigated the effect of the most important insulinotropic western dietary factors, IGF-1 and insulin on acne. SZ95 sebocytes were stimulated with different concentrations of IGF-1 and insulin (0.001, 0.01, 0.1 and 1 μM) for 15 to 120 min ± PI3K inhibitor LY294002 (50 μM). Cytoplasmic and nuclear protein expression of p-Akt and p-FoxO1 as well as FoxO transcriptional activity was analysed. In addition, the proliferation and differentiation of sebocytes and their TLR2/4 expression were determined. We found that high concentrations of IGF-1 and insulin differentially stimulate the PI3K/Akt/FoxO1 pathway by an early up-regulation of cytoplasmic p-Akt and delayed up-regulation of p-FoxO1 resulting in FoxO1 shift to the cytoplasm and the reduction of FoxO transcriptional activity, physiological serum concentration had no effect. IGF-1 at concentrations of 0.1 and 1 μM significantly reduced proliferation but increased differentiation of sebocytes to a greater extent than insulin (0.1 and 1 μM), but up-regulated TLR2/4 expression to comparable extent. These data provide the first in vitro evidence that FoxO1 principally might be involved in the regulation of growth-factor-stimulatory effects on sebaceous lipogenesis and inflammation in the pathological condition of acne. However, the in vivo significance under physiological conditions remains to be elucidated. PMID:26257240

  14. Ellagic acid protects endothelial cells from oxidized low-density lipoprotein-induced apoptosis by modulating the PI3K/Akt/eNOS pathway

    International Nuclear Information System (INIS)

    Endothelial apoptosis is a driving force in atherosclerosis development. Oxidized low-density lipoprotein (oxLDL) promotes inflammatory and thrombotic processes and is highly atherogenic, as it stimulates macrophage cholesterol accumulation and foam cell formation. Previous studies have shown that the phosphatidylinositol 3-kinase/Akt/endothelial nitric oxide synthase/nitric oxide (PI3K/Akt/eNOS/NO) pathway is involved in oxLDL-induced endothelial apoptosis. Ellagic acid, a natural polyphenol found in berries and nuts, has in recent years been the subject of intense research within the fields of cancer and inflammation. However, its protective effects against oxLDL-induced injury in vascular endothelial cells have not been clarified. In the present study, we investigated the anti-apoptotic effect of ellagic acid in human umbilical vein endothelial cells (HUVECs) exposed to oxLDL and explored the possible mechanisms. Our results showed that pretreatment with ellagic acid (5-20 μM) significantly attenuated oxLDL-induced cytotoxicity, apoptotic features, and generation of reactive oxygen species (ROS). In addition, the anti-apoptotic effect of ellagic acid was partially inhibited by a PI3K inhibitor (wortmannin) and a specific eNOS inhibitor (cavtratin) but not by an ERK inhibitor (PD98059). In exploring the underlying mechanisms of ellagic acid action, we found that oxLDL decreased Akt and eNOS phosphorylation, which in turn activated NF-κB and downstream pro-apoptotic signaling events including calcium accumulation, destabilization of mitochondrial permeability, and disruption of the balance between pro- and anti-apoptotic Bcl-2 proteins. Those alterations induced by oxLDL, however, were attenuated by pretreatment with ellagic acid. The inhibition of oxLDL-induced endothelial apoptosis by ellagic acid is due at least in part to its anti-oxidant activity and its ability to modulate the PI3K/Akt/eNOS signaling pathway.

  15. Suppression of SPIN1-mediated PI3K-Akt pathway by miR-489 increases chemosensitivity in breast cancer.

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    Chen, Xu; Wang, Ya-Wen; Xing, Ai-Yan; Xiang, Shuai; Shi, Duan-Bo; Liu, Lei; Li, Yan-Xiang; Gao, Peng

    2016-08-01

    Drug resistance is one of the major obstacles for improving the prognosis of breast cancer patients. Increasing evidence has linked the association of aberrantly expressed microRNAs (miRNAs) with tumour development and progression as well as chemoresistance. Despite recent advances, there is still little known about the potential role and mechanism of miRNAs in breast cancer chemoresistance. Here we describe that 16 miRNAs were found to be significantly down-regulated and 11 up-regulated in drug-resistant breast cancer tissues compared with drug-sensitive tissues, using a miRNA microarray. The results also showed miR-489 to be one of the most down-regulated miRNAs in drug-resistant tissues and cell lines, as confirmed by miRNA microarray screening and real-time quantitative PCR. A decrease in miR-489 expression was associated with chemoresistance as well as lymph node metastasis, increased tumour size, advanced pTNM stage and poor prognosis in breast cancer. Functional analysis revealed that miR-489 increased breast cancer chemosensitivity and inhibited cell proliferation, migration and invasion, both in vitro and in vivo. Furthermore, SPIN1, VAV3, BCL2 and AKT3 were found to be direct targets of miR-489. SPIN1 was significantly elevated in drug-resistant and metastatic breast cancer tissues and inversely correlated with miR-489 expression. High expression of SPIN1 was associated with higher histological grade, lymph node metastasis, advanced pTNM stage and positive progesterone receptor (PR) status. Increased SPIN1 expression enhanced cell migration and invasion, inhibited apoptosis and partially antagonized the effects of miR-489 in breast cancer. PIK3CA, AKT, CREB1 and BCL2 in the PI3K-Akt signalling pathway, demonstrated to be elevated in drug-resistant breast cancer tissues, were identified as downstream effectors of SPIN1. It was further found that either inhibition of SPIN1 or overexpression of miR-489 suppressed the PI3K-Akt signalling pathway. These data

  16. PI3K-Independent AKT Activation in Cancers: A Treasure Trove for Novel Therapeutics

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    Mahajan, Kiran; Mahajan, Nupam P.

    2012-01-01

    AKT/PKB serine threonine kinase, a critical signaling molecule promoting cell growth and survival pathways, is frequently dysregulated in many cancers. Although phosphatidylinositol-3-OH kinase (PI3K), a lipid kinase, is well characterized as a major regulator of AKT activation in response to a variety of ligands, recent studies highlight a diverse group of tyrosine (Ack1/TNK2, Src, PTK6) and serine/threonine (TBK1, IKBKE, DNAPKcs) kinases that activate AKT directly to promote its pro-prolife...

  17. Transmembrane-Bound IL-15–Promoted Epithelial-Mesenchymal Transition in Renal Cancer Cells Requires the Src-Dependent Akt/GSK-3β/β-Catenin Pathway

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    Huaqin Yuan

    2015-05-01

    Full Text Available Intrarenal interleukin-15 (IL-15 plays a major role controlling epithelial survival and polarization both in physiological and pathologic conditions. Herein, we confirmed that human renal cell carcinomas (RCCs express a membrane-bound IL-15 isoform displaying an unusual molecular weight of 27 kDa. Its stimulation with soluble IL-15 receptor α chain (s-IL-15Rα triggers epithelial-mesenchymal transition (EMT process as shown by the down-regulation of E-cadherin and zona occludens 1 and the up-regulation of vimentin and N-cadherin and promotes the migratory and invasive properties of RCC. S-IL-15Rα treatment triggered the Src/PI3K/Akt/GSK-3β pathway and promoted β-catenin nuclei translocation. Deactivation of this pathway by using Src-specific inhibitor PP2, PI3K inhibitor LY294002, and AKT inhibitor MK2206 hampered β-catenin nuclei translocation and suppressed EMT, migration, and invasion of RCC. S-IL-15Rα treatment also enhanced Src-dependent phosphorylation of focal adhesion kinase (FAK and extracellular signal–regulated kinase (Erk1/2. FAK knockdown significantly decreased the migration and invasion of RCC, which suggest that Src-FAK signaling was involved in s-IL-15Rα–favored migration and invasion of RCC. At the same time, inhibitors of Erk1/2 also significantly decreased the migration and invasion of RCC but could not reverse s-IL-15Rα–induced EMT. Taken together, our results reveal that Src-dependent PI3K/Akt/GSK3b/β-catenin pathway is required for s-IL-15Ra–dependent induction of EMT in RCC, while Src-FAK and Src-Erk1/2 signaling were involved in s-IL-15Rα–promoted migration and invasion properties of RCC. Our study provides a better understanding of IL-15 signaling in RCC tumor progression, which may lead to novel targeted therapies and provide some suggestions when using IL-15 in clinic.

  18. 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

  19. 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.

  20. S-Propargyl-cysteine Exerts a Novel Protective Effect on Methionine and Choline Deficient Diet-Induced Fatty Liver via Akt/Nrf2/HO-1 Pathway

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    Wenwen Li

    2016-01-01

    Full Text Available This study investigated the antioxidative effect of S-propargyl-cysteine (SPRC on nonalcoholic fatty liver (NAFLD by treating mice fed a methionine and choline deficient (MCD diet with SPRC for four weeks. We found that SPRC significantly reduced hepatic reactive oxygen species (ROS and methane dicarboxylic aldehyde (MDA levels. Moreover, SPRC also increased the superoxide dismutase (SOD activity. By Western blot, we found that this protective effect of SPRC was importantly attributed to the regulated hepatic antioxidant-related proteins, including protein kinase B (Akt, heme oxygenase-1 (HO-1, nuclear factor erythroid 2-related factor 2 (Nrf2, and cystathionine γ-lyase (CSE, an enzyme that synthesizes hydrogen sulfide. Next, we examined the detailed molecular mechanism of the SPRC protective effect using oleic acid- (OA- induced HepG2 cells. The results showed that SPRC significantly decreased intracellular ROS and MDA levels in OA-induced HepG2 cells by upregulating the phosphorylation of Akt, the expression of HO-1 and CSE, and the translocation of Nrf2. SPRC-induced HO-1 expression and Nrf2 translocation were abolished by the phosphoinositide 3-kinase (PI3K inhibitor LY294002. Moreover, the antioxidative effect of SPRC was abolished by CSE inhibitor DL-propargylglycine (PAG and HO-1 siRNA. Therefore, these results proved that SPRC produced an antioxidative effect on NAFLD through the PI3K/Akt/Nrf2/HO-1 signaling pathway.

  1. Guizhi Fuling Wan, a Traditional Chinese Herbal Formula, Sensitizes Cisplatin-Resistant Human Ovarian Cancer Cells through Inactivation of the PI3K/AKT/mTOR Pathway

    Directory of Open Access Journals (Sweden)

    Li Han

    2016-01-01

    Full Text Available The aim of the study was to explore the possible mechanisms that Guizhi Fuling Wan (GFW enhances the sensitivity of the SKOV3/DDP ovarian cancer cells and the resistant xenograft tumours to cisplatin. Rat medicated sera containing GFW were prepared by administering GFW to rats, and the primary bioactive constituents of the sera were gallic acid, paeonol, and paeoniflorin analysed by HPLC/QqQ MS. Cell counting kit-8 analysis was shown that coincubation of the sera with cisplatin/paclitaxel enhanced significantly the cytotoxic effect of cisplatin or paclitaxel in SKOV3/DDP cells. The presence of the rat medicated sera containing GFW resulted in an increase in rhodamine 123 accumulation by flow cytometric assays and a decrease in the protein levels of P-gp, phosphorylation of AKT at Ser473, and mTOR in a dose-dependent manner in SKOV3/DDP cells by western blot analysis, but the sera had no effect on the protein levels of PI3K p110α and total AKT. The low dose of GFW enhanced the anticancer efficacy of cisplatin and paclitaxel treatment in resistant SKOV3/DDP xenograft tumours. GFW could sensitize cisplatin-resistant SKOV3/DDP cells by inhibiting the protein level and function of P-gp, which may be medicated through inactivation of the PI3K/AKT/mTOR pathway.

  2. Contribution of CFTR to Alveolar Fluid Clearance by Lipoxin A4 via PI3K/Akt Pathway in LPS-Induced Acute Lung Injury

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    Yi Yang

    2013-01-01

    Full Text Available The lipoxins are the first proresolution mediators to be recognized and described as the endogenous “braking signals” for inflammation. We evaluated the anti-inflammatory and proresolution bioactions of lipoxin A4 in our lipopolysaccharide (LPS-induced lung injury model. We demonstrated that lipoxin A4 significantly improved histology of rat lungs and inhibited IL-6 and TNF-α in LPS-induced lung injury. In addition, lipoxin A4 increased alveolar fluid clearance (AFC and the effect of lipoxin A4 on AFC was abolished by CFTRinh-172 (a specific inhibitor of CFTR. Moreover, lipoxin A4 could increase cystic fibrosis transmembrane conductance regulator (CFTR protein expression in vitro and in vivo. In rat primary alveolar type II (ATII cells, LPS decreased CFTR protein expression via activation of PI3K/Akt, and lipoxin A4 suppressed LPS-stimulated phosphorylation of Akt. These results showed that lipoxin A4 enhanced CFTR protein expression and increased AFC via PI3K/Akt pathway. Thus, lipoxin A4 may provide a potential therapeutic approach for acute lung injury.

  3. Metabonomics applied in exploring the antitumour mechanism of physapubenolide on hepatocellular carcinoma cells by targeting glycolysis through the Akt-p53 pathway

    Science.gov (United States)

    Ma, Ting; Fan, Bo-Yi; Zhang, Chao; Zhao, Hui-Jun; Han, Chao; Gao, Cai-Yun; Luo, Jian-Guang; Kong, Ling-Yi

    2016-01-01

    Metabolomics can be used to identify potential markers and discover new targets for future therapeutic interventions. Here, we developed a novel application of the metabonomics method based on gas chromatography-mass spectrometry (GC/MS) analysis and principal component analysis (PCA) for rapidly exploring the anticancer mechanism of physapubenolide (PB), a cytotoxic withanolide isolated from Physalis species. PB inhibited the proliferation of hepatocellular carcinoma cells in vitro and in vivo, accompanied by apoptosis-related biochemical events, including the cleavage of caspase-3/7/9 and PARP. Metabolic profiling analysis revealed that PB disturbed the metabolic pattern and significantly decreased lactate production. This suggests that the suppression of glycolysis plays an important role in the anti-tumour effects induced by PB, which is further supported by the decreased expression of glycolysis-related genes and proteins. Furthermore, the increased level of p53 and decreased expression of p-Akt were observed, and the attenuated glycolysis and enhanced apoptosis were reversed in the presence of Akt cDNA or p53 siRNA. These results confirm that PB exhibits anti-cancer activities through the Akt-p53 pathway. Our study not only reports for the first time the anti-tumour mechanism of PB, but also suggests that PB is a promising therapeutic agent for use in cancer treatments and that metabolomic approaches provide a new strategy to effectively explore the molecular mechanisms of promising anticancer compounds. PMID:27416811

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2015-09-17

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

  6. Morin, a flavonoid from Moraceae, suppresses growth and invasion of the highly metastatic breast cancer cell line MDA-MB‑231 partly through suppression of the Akt pathway.

    Science.gov (United States)

    Jin, Hana; Lee, Won Sup; Eun, So Young; Jung, Ji Hyun; Park, Hyeon-Soo; Kim, Gonsup; Choi, Yung Hyun; Ryu, Chung Ho; Jung, Jin Myung; Hong, Soon Chan; Shin, Sung Chul; Kim, Hye Jung

    2014-10-01

    Morin, a flavonoid found in figs and other Moraceae, displays a variety of biological actions, such as anti-oxidant, anti-inflammatory and anti-carcinogenic. However, the anticancer effects of morin and in particular its anti-metastatic effects are not well known. Therefore, in the present study, we investigated the anticancer effects of morin on highly metastatic human breast cancer cells. Our results showed that morin significantly inhibited the colony forming ability of highly metastatic MDA-MB‑231 breast cancer cells from low doses (50 µM) without cytotoxicity. In addition, morin changed MDA-MB‑231 cell morphology from mesenchymal shape to epithelial shape and inhibited the invasion of MDA-MB‑231 cells in a dose-dependent manner. Morin decreased matrix metalloproteinase-9 (MMP-9) secretion and expression of the mesenchymal marker N-cadherin of MDA-MB‑231 cells, suggesting that morin might suppress the EMT process. Furthermore, morin significantly decreased the phosphorylation of Akt, and inhibition of the Akt pathway significantly reduced MDA-MB‑231 invasion. In an in vivo xenograft mouse model, morin suppressed MDA-MB‑231 cancer cell progression. Taken together, our findings suggest that morin exhibits an inhibitory effect on the cancer progression and EMT process of highly metastatic breast cancer cells at least in part through inhibiting Akt activation. This study provides evidence that morin may have anticancer effects against metastatic breast cancer.

  7. Thymosin β4 induces invasion and migration of human colorectal cancer cells through the ILK/AKT/β-catenin signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    Piao, Zhengri [Research Center for Molecular Therapeutic to GI Tract of Cancer Center, Chonnam National University Hwasun Hospital, Hwasun (Korea, Republic of); Center for Creative Biomedical Scientists (BK-21 Plus Project), Chonnam National University Medical School, Gwangju (Korea, Republic of); Hong, Chang-Soo [Research Center for Molecular Therapeutic to GI Tract of Cancer Center, Chonnam National University Hwasun Hospital, Hwasun (Korea, Republic of); Jung, Mi-Ran [Department of Gastroenterologic Surgery, Chonnam National University Hwasun Hospital, Hwasun (Korea, Republic of); Choi, Chan [Department of Pathology, Chonnam National University Hwasun Hospital, Hwasun (Korea, Republic of); Park, Young-Kyu, E-mail: parkyk@jnu.ac.kr [Research Center for Molecular Therapeutic to GI Tract of Cancer Center, Chonnam National University Hwasun Hospital, Hwasun (Korea, Republic of); Center for Creative Biomedical Scientists (BK-21 Plus Project), Chonnam National University Medical School, Gwangju (Korea, Republic of); Department of Gastroenterologic Surgery, Chonnam National University Hwasun Hospital, Hwasun (Korea, Republic of)

    2014-09-26

    Highlights: • Tβ4 is overexpressed in human colorectal cancer cells. • The overexpression of Tβ4 is correlated with stage of colorectal cancer. • Tβ4 stimulates cell adhesion, invasion, migration and EMT. • Tβ4 activates the ILK/AKT/β-catenin signaling pathway. - Abstract: Thymosin β4 (Tβ4) is a 43-amino-acid peptide involved in many biological processes. However, the precise molecular signaling mechanism(s) of Tβ4 in cell invasion and migration remain unclear. In this study, we show that Tβ4 was significantly overexpressed in colorectal cancer tissues compared to adjacent normal tissues and high levels of Tβ4 were correlated with stage of colorectal cancer, and that Tβ4 expression was associated with morphogenesis and EMT. Tβ4-upregulated cancer cells showed increased adhesion, invasion and migration activity, whereas Tβ4-downregulated cells showed decreased activities. We also demonstrated that Tβ4 interacts with ILK, which promoted the phosphorylation and activation of AKT, the phosphorylation and inactivation of GSK3β, the expression and nuclear localization of β-catenin, and integrin receptor activation. These results suggest that Tβ4 is an important regulator of the ILK/AKT/β-catenin/Integrin signaling cascade to induce cell invasion and migration in colorectal cancer cells, and is a potential target for cancer treatment.

  8. Thymosin β4 induces invasion and migration of human colorectal cancer cells through the ILK/AKT/β-catenin signaling pathway

    International Nuclear Information System (INIS)

    Highlights: • Tβ4 is overexpressed in human colorectal cancer cells. • The overexpression of Tβ4 is correlated with stage of colorectal cancer. • Tβ4 stimulates cell adhesion, invasion, migration and EMT. • Tβ4 activates the ILK/AKT/β-catenin signaling pathway. - Abstract: Thymosin β4 (Tβ4) is a 43-amino-acid peptide involved in many biological processes. However, the precise molecular signaling mechanism(s) of Tβ4 in cell invasion and migration remain unclear. In this study, we show that Tβ4 was significantly overexpressed in colorectal cancer tissues compared to adjacent normal tissues and high levels of Tβ4 were correlated with stage of colorectal cancer, and that Tβ4 expression was associated with morphogenesis and EMT. Tβ4-upregulated cancer cells showed increased adhesion, invasion and migration activity, whereas Tβ4-downregulated cells showed decreased activities. We also demonstrated that Tβ4 interacts with ILK, which promoted the phosphorylation and activation of AKT, the phosphorylation and inactivation of GSK3β, the expression and nuclear localization of β-catenin, and integrin receptor activation. These results suggest that Tβ4 is an important regulator of the ILK/AKT/β-catenin/Integrin signaling cascade to induce cell invasion and migration in colorectal cancer cells, and is a potential target for cancer treatment

  9. Quercetin inhibits angiogenesis mediated human prostate tumor growth by targeting VEGFR- 2 regulated AKT/mTOR/P70S6K signaling pathways.

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    Poyil Pratheeshkumar

    Full Text Available Angiogenesis is a crucial step in the growth and metastasis of cancers, since it enables the growing tumor to receive oxygen and nutrients. Cancer prevention using natural products has become an integral part of cancer control. We studied the antiangiogenic activity of quercetin using ex vivo, in vivo and in vitro models. Rat aortic ring assay showed that quercetin at non-toxic concentrations significantly inhibited microvessel sprouting and exhibited a significant inhibition in the proliferation, migration, invasion and tube formation of endothelial cells, which are key events in the process of angiogenesis. Most importantly, quercetin treatment inhibited ex vivo angiogenesis as revealed by chicken egg chorioallantoic membrane assay (CAM and matrigel plug assay. Western blot analysis showed that quercetin suppressed VEGF induced phosphorylation of VEGF receptor 2 and their downstream protein kinases AKT, mTOR, and ribosomal protein S6 kinase in HUVECs. Quercetin (20 mg/kg/d significantly reduced the volume and the weight of solid tumors in prostate xenograft mouse model, indicating that quercetin inhibited tumorigenesis by targeting angiogenesis. Furthermore, quercetin reduced the cell viability and induced apoptosis in prostate cancer cells, which were correlated with the downregulation of AKT, mTOR and P70S6K expressions. Collectively the findings in the present study suggest that quercetin inhibits tumor growth and angiogenesis by targeting VEGF-R2 regulated AKT/mTOR/P70S6K signaling pathway, and could be used as a potential drug candidate for cancer therapy.

  10. Dual inhibition of CDK4/Rb and PI3K/AKT/mTOR pathways by ON123300 induces synthetic lethality in mantle cell lymphomas.

    Science.gov (United States)

    Divakar, S K A; Ramana Reddy, M V; Cosenza, S C; Baker, S J; Perumal, D; Antonelli, A C; Brody, J; Akula, B; Parekh, S; Reddy, E Premkumar

    2016-01-01

    This study describes the characterization of a novel kinase inhibitor, ON123300, which inhibits CDK4/6 (cyclin-dependent kinases 4 and 6) and phosphatidylinositol 3 kinase-δ (PI3K-δ) and exhibits potent activity against mantle cell lymphomas (MCLs) both in vitro and in vivo. We examined the effects of PD0332991 and ON123300 on cell cycle progression, modulation of the retinoblastoma (Rb) and PI3K/AKT pathways, and the induction of apoptosis in MCL cell lines and patient-derived samples. When Granta 519 and Z138C cells were incubated with PD0332991 and ON123300, both compounds were equally efficient in their ability to inhibit the phosphorylation of Rb family proteins. However, only ON123300 inhibited the phosphorylation of proteins associated with the PI3K/AKT pathway. Cells treated with PD0332991 rapidly accumulated in the G0/G1 phase of cell cycle as a function of increasing concentration. Although ON123300-treated cells arrested similarly at lower concentrations, higher concentrations resulted in the induction of apoptosis, which was not observed in PD0332991-treated samples. Mouse xenograft assays also showed a strong inhibition of MCL tumor growth in ON123300-treated animals. Finally, treatment of ibrutinib-sensitive and -resistant patient-derived MCLs with ON123300 also triggered apoptosis and inhibition of the Rb and PI3K/AKT pathways, suggesting that this compound might be an effective agent in MCL, including ibrutinib-resistant forms of the disease. PMID:26174628

  11. Matrix metalloproteinase-1 induction by diethyldithiocarbamate is regulated via Akt and ERK/miR222/ETS-1 pathways in hepatic stellate cells.

    Science.gov (United States)

    Liu, Tianhui; Wang, Ping; Cong, Min; Zhang, Dong; Liu, Lin; Li, Hongyi; Zhai, Qingling; Li, Zhuo; Jia, Jidong; You, Hong

    2016-08-01

    Matrix metalloproteinase-1 (MMP-1) plays an important role in fibrolysis by degrading excessively deposited collagen I and III. We previously demonstrated that diethyldithiocarbamate (DDC) up-regulates MMP-1 in hepatic stellate cells via the ERK1/2 and Akt signalling pathways. In the current study, we attempted to further explore the molecular mechanisms involved in the regulation of MMP-1. We treated a co-cultured system that included hepatocytes (C3A) and hepatic stellate cells (LX-2) with DDC. The data revealed that the transcriptional factor ETS-1, which is an important regulator of MMP-1, was up-regulated in LX-2 cells following DDC treatment. Furthermore, the up-regulation of MMP-1 by DDC has been abrogated through employing si-ETS-1 to block expression of ETS-1. We found that DDC significantly inhibited the expression of miR-222 in LX-2 cells. We transfected miR-222 mimic into LX-2 cells and then co-cultured the cells with C3A. The up-regulation of ETS-1 and MMP-1 in LX-2 cells treated with DDC were inhibited after miR-222 mimic transfection. These data indicate that DDC up-regulated MMP-1 in LX-2 cells through the miR-222/ETS-1 pathway. Finally, we treated the co-cultured system with an Akt inhibitor (T3830) and an ERK1/2 inhibitor (U0126). Both T3830 and U0126 blocked the suppression of miR-222 by DDC in LX-2. Collectively, these data indicate that DDC up-regulated MMP-1 in LX-2 cells through the Akt and ERK/miR-222/ETS-1 pathways. Our study provides experimental data that will aid the control of the process of fibrolysis in liver fibrosis prevention and treatment.

  12. Antitumor effect of manumycin on colorectal cancer cells by increasing the reactive oxygen species production and blocking PI3K-AKT pathway

    Directory of Open Access Journals (Sweden)

    Zhang JY

    2016-05-01

    Full Text Available Jingyu Zhang,1 Hua Jiang,2 Li Xie,1 Jing Hu,1 Li Li,1 Mi Yang,1 Lei Cheng,1 Baorui Liu,1 Xiaoping Qian1 1Department of the Comprehensive Cancer Center, Affiliated Nanjing Drum Tower Hospital, Nanjing Medical University, 2Department of Oncology, Affiliated Changzhou No 2 People’s Hospital, Nanjing Medical University, Nanjing, People’s Republic of China Abstract: Manumycin is a natural, well-tolerated microbial metabolite and is regarded as a farnesyltransferase inhibitor. Some data suggest that manumycin inhibits proliferation of diverse cancer cells through various pathways. However, the antitumor effect of manumycin on colorectal cancer (CRC remains unknown. In the present study, we investigated the antitumor effect of manumycin on CRC in vitro and in vivo. The results of cell viability assay revealed that the proliferation of the CRC cells was significantly inhibited by manumycin. Moreover, cell apoptosis induced by manumycin was also found in a time- and dose-dependent manner. Interestingly, treatment of the CRC cells with manumycin resulted in increased generation of reactive oxygen species. Subsequently, manumycin also decreased the phosphorylation of phosphatidylinositol 3-kinase (PI3K and AKT, as well as the expression of caspase-9 and poly(ADP-ribose polymerase (PARP in a time-dependent manner. In addition, we found that N-acetyl-L-cysteine (NAC attenuated the effect of manumycin on the PI3K-AKT pathway, and wortmannin reduced the effect of manumycin on caspase-9 and PARP expression. More importantly, the anticancer effect of manumycin was also observed in established tumor xenografts. Taken together, these findings supported the potential application of manumycin against colorectal carcinoma. Keywords: manumycin, colorectal cancer, PI3K-AKT pathway, ROS

  13. Matrix metalloproteinase-1 induction by diethyldithiocarbamate is regulated via Akt and ERK/miR222/ETS-1 pathways in hepatic stellate cells.

    Science.gov (United States)

    Liu, Tianhui; Wang, Ping; Cong, Min; Zhang, Dong; Liu, Lin; Li, Hongyi; Zhai, Qingling; Li, Zhuo; Jia, Jidong; You, Hong

    2016-08-01

    Matrix metalloproteinase-1 (MMP-1) plays an important role in fibrolysis by degrading excessively deposited collagen I and III. We previously demonstrated that diethyldithiocarbamate (DDC) up-regulates MMP-1 in hepatic stellate cells via the ERK1/2 and Akt signalling pathways. In the current study, we attempted to further explore the molecular mechanisms involved in the regulation of MMP-1. We treated a co-cultured system that included hepatocytes (C3A) and hepatic stellate cells (LX-2) with DDC. The data revealed that the transcriptional factor ETS-1, which is an important regulator of MMP-1, was up-regulated in LX-2 cells following DDC treatment. Furthermore, the up-regulation of MMP-1 by DDC has been abrogated through employing si-ETS-1 to block expression of ETS-1. We found that DDC significantly inhibited the expression of miR-222 in LX-2 cells. We transfected miR-222 mimic into LX-2 cells and then co-cultured the cells with C3A. The up-regulation of ETS-1 and MMP-1 in LX-2 cells treated with DDC were inhibited after miR-222 mimic transfection. These data indicate that DDC up-regulated MMP-1 in LX-2 cells through the miR-222/ETS-1 pathway. Finally, we treated the co-cultured system with an Akt inhibitor (T3830) and an ERK1/2 inhibitor (U0126). Both T3830 and U0126 blocked the suppression of miR-222 by DDC in LX-2. Collectively, these data indicate that DDC up-regulated MMP-1 in LX-2 cells through the Akt and ERK/miR-222/ETS-1 pathways. Our study provides experimental data that will aid the control of the process of fibrolysis in liver fibrosis prevention and treatment. PMID:27412967

  14. Activation of EGFR/ERBB2 via Pathways Involving ERK1/2, P38 MAPK, AKT and FOXO Enhances Recovery of Diabetic Hearts from Ischemia-Reperfusion Injury

    Science.gov (United States)

    Akhtar, Saghir; Yousif, Mariam H. M.; Chandrasekhar, Bindu; Benter, Ibrahim F.

    2012-01-01

    This study characterized the effects of diabetes and/or ischemia on epidermal growth factor receptor, EGFR, and/or erbB2 signaling pathways on cardiac function. Isolated heart perfusion model of global ischemia was used to study the effect of chronic inhibition or acute activation of EGFR/erbB2 signaling on cardiac function in a rat model of type-1 diabetes. Induction of diabetes with streptozotocin impaired recovery of cardiac function (cardiac contractility and hemodynamics) following 40 minutes of global ischemia in isolated hearts. Chronic treatment with AG825 or AG1478, selective inhibitors of erbB2 and EGFR respectively, did not affect hyperglycemia but led to an exacerbation whereas acute administration of the EGFR ligand, epidermal growth factor (EGF), led to an improvement in cardiac recovery in diabetic hearts. Diabetes led to attenuated dimerization and phosphorylation of cardiac erbB2 and EGFR receptors that was associated with reduced signaling via extracellular-signal-regulated kinase 1/2 (ERK1/2), p38 mitogen activated protein (MAP) kinase and AKT (protein kinase B). Ischemia was also associated with reduced cardiac signaling via these molecules whereas EGF-treatment opposed diabetes and/or ischemia induced changes in ERK1/2, p38 MAP kinase, and AKT-FOXO signaling. Losartan treatment improved cardiac function in diabetes but also impaired EGFR phosphorylation in diabetic heart. Co-administration of EGF rescued Losartan-mediated reduction in EGFR phosphorylation and significantly improved cardiac recovery more than with either agent alone. EGFR/erbB2 signaling is an important cardiac survival pathway whose activation, particularly in diabetes, ischemia or following treatment with drugs that inhibit this cascade, significantly improves cardiac function. These findings may have clinical relevance particularly in the treatment of diabetes-induced cardiac dysfunction. PMID:22720029

  15. Activation of EGFR/ERBB2 via pathways involving ERK1/2, P38 MAPK, AKT and FOXO enhances recovery of diabetic hearts from ischemia-reperfusion injury.

    Directory of Open Access Journals (Sweden)

    Saghir Akhtar

    Full Text Available This study characterized the effects of diabetes and/or ischemia on epidermal growth factor receptor, EGFR, and/or erbB2 signaling pathways on cardiac function. Isolated heart perfusion model of global ischemia was used to study the effect of chronic inhibition or acute activation of EGFR/erbB2 signaling on cardiac function in a rat model of type-1 diabetes. Induction of diabetes with streptozotocin impaired recovery of cardiac function (cardiac contractility and hemodynamics following 40 minutes of global ischemia in isolated hearts. Chronic treatment with AG825 or AG1478, selective inhibitors of erbB2 and EGFR respectively, did not affect hyperglycemia but led to an exacerbation whereas acute administration of the EGFR ligand, epidermal growth factor (EGF, led to an improvement in cardiac recovery in diabetic hearts. Diabetes led to attenuated dimerization and phosphorylation of cardiac erbB2 and EGFR receptors that was associated with reduced signaling via extracellular-signal-regulated kinase 1/2 (ERK1/2, p38 mitogen activated protein (MAP kinase and AKT (protein kinase B. Ischemia was also associated with reduced cardiac signaling via these molecules whereas EGF-treatment opposed diabetes and/or ischemia induced changes in ERK1/2, p38 MAP kinase, and AKT-FOXO signaling. Losartan treatment improved cardiac function in diabetes but also impaired EGFR phosphorylation in diabetic heart. Co-administration of EGF rescued Losartan-mediated reduction in EGFR phosphorylation and significantly improved cardiac recovery more than with either agent alone. EGFR/erbB2 signaling is an important cardiac survival pathway whose activation, particularly in diabetes, ischemia or following treatment with drugs that inhibit this cascade, significantly improves cardiac function. These findings may have clinical relevance particularly in the treatment of diabetes-induced cardiac dysfunction.

  16. Ginsenoside Rg1 protects human umbilical cord blood-derived stromal cells against tert-Butyl hydroperoxide-induced apoptosis through Akt-FoxO3a-Bim signaling pathway.

    Science.gov (United States)

    Liu, Ying; Yi, Long; Wang, Lu; Chen, Linbo; Chen, Xiongbin; Wang, Yaping

    2016-10-01

    Human umbilical cord blood-derived stromal cells (hUCBDSCs) possess strong capability of supporting hematopoiesis and immune regulation, whereas some stress conditions cause reactive oxygen species (ROS) accumulation and then lead to oxidative injury and cell apoptosis. Ginsenoside Rg1 (G-Rg1) has been demonstrated to exert antioxidative and prosurvival effects in many cell types. In this study, the tert-Butyl hydroperoxide (t-BHP), an analog of hydroperoxide, was utilized to mimic the oxidative damage to hUCBDSCs. We aimed to investigate the effects of Ginsenoside Rg1 on protecting hUCBDSCs from t-BHP-induced oxidative injury and apoptosis, as well as the possible signaling pathway involved. It was shown that the treatment of hUCBDSCs with G-Rg1 markedly restored the t-BHP-induced cell viability loss, promoted the CFU-F formation, and inhibited cell apoptosis. G-Rg1 also caused a reduced production of LDH and MDA while significantly enhancing the activity of SOD. Mechanistically, G-Rg1 promoted the phosphorylation of Akt and FoxO3a and led to the cytoplasmic translocation of FoxO3a, which in turn suppressed FoxO3a-modulated expression of proapoptotic Bim and elevated the ratio of Bcl-2 to Bax. All these results suggest that G-Rg1 enhances the survival of t-BHP-induced hUCBDSCs and protects them against apoptosis at least partially through Akt-FoxO3a-Bim signaling pathway. PMID:27522666

  17. Activation of EGFR/ERBB2 via pathways involving ERK1/2, P38 MAPK, AKT and FOXO enhances recovery of diabetic hearts from ischemia-reperfusion injury.

    Science.gov (United States)

    Akhtar, Saghir; Yousif, Mariam H M; Chandrasekhar, Bindu; Benter, Ibrahim F

    2012-01-01

    This study characterized the effects of diabetes and/or ischemia on epidermal growth factor receptor, EGFR, and/or erbB2 signaling pathways on cardiac function. Isolated heart perfusion model of global ischemia was used to study the effect of chronic inhibition or acute activation of EGFR/erbB2 signaling on cardiac function in a rat model of type-1 diabetes. Induction of diabetes with streptozotocin impaired recovery of cardiac function (cardiac contractility and hemodynamics) following 40 minutes of global ischemia in isolated hearts. Chronic treatment with AG825 or AG1478, selective inhibitors of erbB2 and EGFR respectively, did not affect hyperglycemia but led to an exacerbation whereas acute administration of the EGFR ligand, epidermal growth factor (EGF), led to an improvement in cardiac recovery in diabetic hearts. Diabetes led to attenuated dimerization and phosphorylation of cardiac erbB2 and EGFR receptors that was associated with reduced signaling via extracellular-signal-regulated kinase 1/2 (ERK1/2), p38 mitogen activated protein (MAP) kinase and AKT (protein kinase B). Ischemia was also associated with reduced cardiac signaling via these molecules whereas EGF-treatment opposed diabetes and/or ischemia induced changes in ERK1/2, p38 MAP kinase, and AKT-FOXO signaling. Losartan treatment improved cardiac function in diabetes but also impaired EGFR phosphorylation in diabetic heart. Co-administration of EGF rescued Losartan-mediated reduction in EGFR phosphorylation and significantly improved cardiac recovery more than with either agent alone. EGFR/erbB2 signaling is an important cardiac survival pathway whose activation, particularly in diabetes, ischemia or following treatment with drugs that inhibit this cascade, significantly improves cardiac function. These findings may have clinical relevance particularly in the treatment of diabetes-induced cardiac dysfunction.

  18. WNT16B is a new marker of cellular senescence that regulates p53 activity and the phosphoinositide 3-kinase/AKT pathway.

    Science.gov (United States)

    Binet, Romuald; Ythier, Damien; Robles, Ana I; Collado, Manuel; Larrieu, Delphine; Fonti, Claire; Brambilla, Elisabeth; Brambilla, Christian; Serrano, Manuel; Harris, Curtis C; Pedeux, Rémy

    2009-12-15

    Senescence is a tumor suppression mechanism that is induced by several stimuli, including oncogenic signaling and telomere shortening, and controlled by the p53/p21(WAF1) signaling pathway. Recently, a critical role for secreted factors has emerged, suggesting that extracellular signals are necessary for the onset and maintenance of senescence. Conversely, factors secreted by senescent cells may promote tumor growth. By using expression profiling techniques, we searched for secreted factors that were overexpressed in fibroblasts undergoing replicative senescence. We identified WNT16B, a member of the WNT family of secreted proteins. We found that WNT16B is overexpressed in cells undergoing stress-induced premature senescence and oncogene-induced senescence in both MRC5 cell line and the in vivo murine model of K-Ras(V12)-induced senescence. By small interfering RNA experiments, we observed that both p53 and WNT16B are necessary for the onset of replicative senescence. WNT16B expression is required for the full transcriptional activation of p21(WAF1). Moreover, WNT16B regulates activation of the phosphoinositide 3-kinase (PI3K)/AKT pathway. Overall, we identified WNT16B as a new marker of senescence that regulates p53 activity and the PI3K/AKT pathway and is necessary for the onset of replicative senescence.

  19. IGF-1 promotes Brn-4 expression and neuronal differentiation of neural stem cells via the PI3K/Akt pathway.

    Directory of Open Access Journals (Sweden)

    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.

  20. Effects of phycocyanin on INS-1 pancreatic β-cell mediated by PI3K/Akt/FoxO1 signaling pathway.

    Science.gov (United States)

    Gao, Yingnv; Liao, Gaoyong; Xiang, Chenxi; Yang, Xuegan; Cheng, Xiaodong; Ou, Yu

    2016-02-01

    The level of methylglyoxal (MG), which is a side-product of metabolic pathways, particularly in glycolysis, is elevated in diabetes. Notably, the accumulation of MG causes a series of pathological changes. Phycocyanin (PC) has been demonstrated to show insulin-sensitizing effect, however, the underlying molecular mechanism remains elusive. The aim of this study was to investigate the protective effects of PC on INS-1 rat insulinoma β-cell against MG-induced cell dysfunction, as well as the underlying mechanisms. PC was preliminarily verified to time-dependently activate PI3-kinase (PI3K) pathway, but the PI3K-specific inhibitor Wortmannin blocked the effect of PC. Glucose-stimulated insulin secretion (GSIS) was impaired in MG-treated INS-1 cells. Furthermore, MG induced dephosphorylation of Akt and FoxO1, resulting in nuclear localization and transactivation of FoxO1. Nevertheless, these effects were all effectively attenuated by PC. The ameliorated insulin secretion was related to the changes of FoxO1 mediated by PC, which demonstrated by RNA interference. And, the dosage used in the above experiments did not affect β-cell viability and apoptosis, although long-term MG induced cell apoptosis and mitochondrial dysfunction. In conclusion, PC was capable to protect INS-1 pancreatic β-cell against MG-induced cell dysfunction through modulating PI3K/Akt pathway and the downstream FoxO1. PMID:26616456

  1. WT1 is involved in the Akt-JNK pathway dependent autophagy through directly regulating Gas1 expression in human osteosarcoma cells.

    Science.gov (United States)

    Mo, Hao; He, Juliang; Yuan, Zhenchao; Mo, Ligen; Wu, Zhenjie; Lin, Xiang; Liu, Bin; Guan, Jian

    2016-09-01

    Macroautophagy (herein termed autophagy) works as a protective mechanism in tumorigenesis and development under metabolic stress condition. Multitudes of genes have been found involved in this process during past decades. In the present study, we report that Wilm's tumor suppressor1 (WT1) is involved in autophagy in osteosarcoma (OS) cells. WT1, a transcription factor with multitude of target genes, expresses in a majority of cancer types. Though wide-ranging effect of WT1 is now well documented, the function of WT1 in tumors remains poorly defined. In this chapter, it is found that high expression of WT1 positively correlates with active autophagy in human osteosarcoma cells. And further study on cell signaling pathway illustrates that Akt/JNK pathway acts as a positive regulator of autophagy induced by WT1. Here, we present evidence that WT1 modulates Akt/JNK signaling pathway mediated autophagy by controlling the expression of growth arrest-specific 1 (Gas1). We show that WT1 is required for Gas1 transcription in osteosarcoma cells. And Gas1 is upregulated followed WT1 overexpression in a time-dependent manner. Loss of Gas1 results in a reduction of WT1-induced autophagy. PMID:27453337

  2. Tamoxifen inhibits tumor cell invasion and metastasis in mouse melanoma through suppression of PKC/MEK/ERK and PKC/PI3K/Akt pathways

    Energy Technology Data Exchange (ETDEWEB)

    Matsuoka, Hiroshi [Division of Pharmacotherapy, Kinki University School of Pharmacy, Kowakae, Higashi-Osaka 577-8502 (Japan); Department of Pharmacy, Nara Hospital, Kinki University School of Medicine, 1248-1 Ikoma, Nara 630-0293 (Japan); Tsubaki, Masanobu [Division of Pharmacotherapy, Kinki University School of Pharmacy, Kowakae, Higashi-Osaka 577-8502 (Japan); Yamazoe, Yuzuru [Department of Pharmacy, Kinki University Hospital, Osakasayama, Osaka 589-8511 (Japan); Ogaki, Mitsuhiko [Department of Pharmacy, Higahiosaka City General Hospital, Higashi-osaka, Osaka 578-8588 (Japan); Satou, Takao; Itoh, Tatsuki [Department of Pathology, Kinki University School of Medicine, Osakasayama, Osaka 589-8511 (Japan); Kusunoki, Takashi [Department of Otolaryngology, Juntendo University School of Medicine, Tokyo (Japan); Nishida, Shozo, E-mail: nishida@phar.kindai.ac.jp [Division of Pharmacotherapy, Kinki University School of Pharmacy, Kowakae, Higashi-Osaka 577-8502 (Japan)

    2009-07-15

    In melanoma, several signaling pathways are constitutively activated. Among these, the protein kinase C (PKC) signaling pathways are activated through multiple signal transduction molecules and appear to play major roles in melanoma progression. Recently, it has been reported that tamoxifen, an anti-estrogen reagent, inhibits PKC signaling in estrogen-negative and estrogen-independent cancer cell lines. Thus, we investigated whether tamoxifen inhibited tumor cell invasion and metastasis in mouse melanoma cell line B16BL6. Tamoxifen significantly inhibited lung metastasis, cell migration, and invasion at concentrations that did not show anti-proliferative effects on B16BL6 cells. Tamoxifen also inhibited the mRNA expressions and protein activities of matrix metalloproteinases (MMPs). Furthermore, tamoxifen suppressed phosphorylated extracellular signal-regulated kinase 1/2 (ERK1/2) and Akt through the inhibition of PKC{alpha} and PKC{delta} phosphorylation. However, other signal transduction factor, such as p38 mitogen-activated protein kinase (p38MAPK) was unaffected. The results indicate that tamoxifen suppresses the PKC/mitogen-activated protein kinase kinase (MEK)/ERK and PKC/phosphatidylinositol-3 kinase (PI3K)/Akt pathways, thereby inhibiting B16BL6 cell migration, invasion, and metastasis. Moreover, tamoxifen markedly inhibited not only developing but also clinically evident metastasis. These findings suggest that tamoxifen has potential clinical applications for the treatment of tumor cell metastasis.

  3. Claulansine F promoted the neuronal differentiation of neural stem and progenitor cells through Akt/GSK-3β/β-catenin pathway.

    Science.gov (United States)

    Huang, Ju-Yang; Ma, Yin-Zhong; Yuan, Yu-He; Zuo, Wei; Chu, Shi-Feng; Liu, Hang; Du, Guan-Hua; Zhang, Dong-Ming; Chen, Nai-Hong

    2016-09-01

    The persistence of neurogenesis raises the idea that neurons produced by the resident or transplanted neural stem cells could replace the neurons lost from brain injury or neurodegenerative disease. Therefore, compounds or methods for promoting neuronal differentiation become the focus of neurodegenerative disease therapy research. Claulansine F (Clau F), a newly discovered carbazole alkaloid, has been showed to induce neuritogenesis in PC12 cells. Herein, we studied the effect of Clau F on neuronal differentiation of neural stem/progenitor cells (NS/PCs). The current study demonstrated that Clau F initiated neuronal differentiation with a significant increase of TuJ1-positive cells and TuJ1 protein levels. We also found that Clau F promoted the maturity and sustainability of neurons by increasing MAP2-positive cells and MAP2 protein levels. At the same time, Clau F significantly inhibited the proliferation of NS/PCs. The underlying mechanism of Clau F was preliminary explored. Clau F treatment resulted in a profound increase of phosphorylation of Akt and GSK-3β, which led to GSK-3β inhibition and subsequently the nuclear accumulation of β-catenin. Further, the interaction between β-catenin and p300 in the nucleus was enhanced and the transcription of p300/β-catenin responsive genes were increased significantly (c-jun, fra-1) by Clau F. Importantly, the positive effect of Clau F on neuronal differentiation was abolished by Akti-1/2, a specific inhibitor of Akt-1/2 kinase, which indicated the involvement of Akt/GSK-3β in Clau F-mediated neuronal differentiation. In conclusion, these data suggested that Clau F promoted neuronal differentiation through Akt/GSK-3β/β-catenin signaling pathway in NS/PCs. PMID:27179990

  4. VEGF is upregulated by hypoxia-induced mitogenic factor via the PI-3K/Akt-NF-κB signaling pathway

    Directory of Open Access Journals (Sweden)

    Huang Chuanshu

    2006-03-01

    Full Text Available Abstract Background Hypoxia-induced mitogenic factor (HIMF is developmentally regulated and plays an important role in lung pathogenesis. We initially found that HIMF promotes vascular tubule formation in a matrigel plug model. In this study, we investigated the mechanisms which HIMF enhances expression of vascular endothelial growth factor (VEGF in lung tissues and epithelial cells. Methods Recombinant HIMF protein was intratracheally instilled into adult mouse lungs, VEGF expression was examined by immunohistochemical staining and Western blot. The promoter-luciferase reporter assay, RT-PCR, and Western blot were performed to examine the effects of HIMF on VEGF expression in mouse lung epithelial cell line MLE-12. The activation of NF-kappa B (NF-κB and phosphorylation of Akt, IKK and IκBα were examined by luciferase assay and Western blot, respectively. Results Intratracheal instillation of HIMF protein resulted in significant increase of VEGF, mainly localized to airway epithelial and alveolar type II cells. Deletion of NF-κB binding sites within VEGF promoter abolished HIMF-induced VEGF expression in MLE-12 cells, suggesting that activation of NF-κB is essential for VEGF upregulation induced by HIMF. Stimulation of lung epithelial cells by HIMF resulted in phosphorylation of IKK and IκBα, leading to activation of NF-κB. In addition, HIMF strongly induced Akt phosphorylation, and suppression of Akt activation by specific inhibitors and dominant negative mutants for PI-3K, and IKK or IκBα blocked HIMF-induced NF-κB activation and attenuated HIMF-induced VEGF production. Conclusion These results suggest that HIMF enhances VEGF production in mouse lung epithelial cells in a PI-3K/Akt-NF-κB signaling pathway-dependent manner, and may play critical roles in pulmonary angiogenesis.

  5. Protective Effect of DHT on Apoptosis Induced by U18666A via PI3K/Akt Signaling Pathway in C6 Glial Cell Lines.

    Science.gov (United States)

    Yao, Kai; Wu, Junfeng; Zhang, Jianfeng; Bo, Jimei; Hong, Zhen; Zu, Hengbing

    2016-07-01

    Various useful animal models, such as Alzheimer's disease and Niemann-Pick disease, were provided by U18666A. However, the pathogenesis of U18666A-induced diseases, including U18666A-mediated apoptosis, remains incompletely elucidated, and therapeutic strategies are still limited. Dihydrotestosterone (DHT) has been reported to contribute to the prevention and treatment of neurodegenerative disorders. Our study investigated the neuroprotective activity of DHT in U18666A-related diseases. Apoptosis of C6 cells was detected by Hoechst 33258 fluorescent staining and flow cytometry with annexin V-FITC/PI dual staining. Cell viability was assessed using Cell Counting Kit-8. Expression of apoptosis-related proteins, such as Akt, seladin-1, Bcl-2 family proteins, and caspase-3, was determined using Western blot. Our results demonstrated that the apoptotic rate of C6 cells significantly increased after U18666A addition, but was remarkably reduced after DHT treatment. Pretreatment with DHT attenuated U18666A-induced cell viability loss. PI3K inhibitor LY294002 could suppress DHT anti-apoptotic effect. Furthermore, we discovered that U18666A could significantly downregulate seladin-1 expression in a dose-dependent manner, but no significant change was observed in Bcl-xL, Bax, and P-Akt protein expressions. Compared with U18666A-treated group, the expression of P-Akt, seladin-1, and Bcl-xL significantly increased, and the expression of Bax and caspase-3 remarkably reduced after DHT treatment. However, in the presence of LY294002, the effect of DHT was reversed. In conclusion, we found that seladin-1 may take part in U18666A-induced apoptosis. DHT may inhibit U18666A-induced apoptosis by regulating downstream apoptosis-related proteins including seladin-1, caspase-3, Bcl-xL, and Bax through activation of the PI3K/Akt signal pathway. PMID:26340949

  6. Non-tumor tissue derived interleukin-17B activates IL-17RB/AKT/β-catenin pathway to enhance the stemness of gastric cancer.

    Science.gov (United States)

    Bie, Qingli; Sun, Caixia; Gong, Aihua; Li, Chunye; Su, Zhaoliang; Zheng, Dong; Ji, Xiaoyun; Wu, Yumin; Guo, Qi; Wang, Shengjun; Xu, Huaxi

    2016-05-05

    Inflammation is a critical component involved in tumor progression. Interleukin-17 (IL-17) belongs to a relatively new family of cytokines that has been associated with the progression of cancers. However, the role of IL-17B/IL-17RB (IL-17 receptor B) signaling to stemness of gastric cancer remains unknown. Here, we confirmed that the expression of IL-17RB in gastric cancer tissues was significantly increased, that overexpression was associated with poor prognosis of gastric cancer patients, and that overexpression was positively correlated with some stemness markers. Interestingly, the expression of IL-17B was upregulated in patient serum rather than gastric tumor tissues. Furthermore, exogenous rIL-17B significantly promoted the stemness of gastric cancer cells depending on IL-17RB and induced the expression of IL-17RB. Simultaneously, the expression of phosphorylated AKT, GSK-3β, and β-catenin as well as the nuclear translocation of β-catenin were significantly increased in the MGC-803 cell in a dose-dependent manner, when treated with rIL-17B. The AKT inhibitor, LY294002, and the knockdown of AKT expression reversed the rIL-17B-induced upregulation of β-catenin and some stemness markers. Together, our results indicate that the IL-17B/IL-17RB signal can promote the growth and migration of tumor cells, and upregulate cell stemness through activating the AKT/β-catenin pathway in gastric cancer, suggesting that IL-17RB may be a novel target in human gastric cancer therapy.

  7. Long-term low-dose α-particle enhanced the potential of malignant transformation in human bronchial epithelial cells through MAPK/Akt pathway

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Weili; Xiao, Linlin; Dong, Chen; He, Mingyuan; Pan, Yan; Xie, Yuexia; Tu, Wenzhi; Fu, Jiamei; Shao, Chunlin, E-mail: clshao@shmu.edu.cn

    2014-05-09

    Highlights: • Multi-exposures of 25 mGy α-ray enhanced cell proliferation, adhesion, and invasion. • MAPK/Akt but not JNK/P66 was positively correlated with cell invasive phenotypes. • LDR of α-irradiation triggers cell malignant transformation through MAPK/Akt. - Abstract: Since the wide usage of ionizing radiation, the cancer risk of low dose radiation (LDR) (<0.1 Gy) has become attractive for a long time. However, most results are derived from epidemiologic studies on atomic-bomb survivors and nuclear accidents surrounding population, and the molecular mechanism of this risk is elusive. To explore the potential of a long-term LDR-induced malignant transformation, human bronchial epithelial cells Beas-2B were fractionally irradiated with 0.025 Gy α-particles for 8 times in total and then further cultured for 1–2 months. It was found that the cell proliferation, the abilities of adhesion and invasion, and the protein expressions of p-ERK, p-Akt, especially p-P38 were not only increased in the multiply-irradiated cells but also in their offspring 1–2 months after the final exposure, indicating high potentiality of cell malignant transformation. On opposite, the expressions of p-JNK and p-P66 were diminished in the subcultures of irradiated cells and thus may play a role of negative regulation in canceration. When the cells were transferred with p38 siRNA, the LDR-induced enhancements of cell adhesion and invasion were significantly reduced. These findings suggest that long-term LDR of α-particles could enhance the potential of malignant transformation incidence in human bronchial epithelial cells through MAPK/Akt pathway.

  8. Claulansine F promoted the neuronal differentiation of neural stem and progenitor cells through Akt/GSK-3β/β-catenin pathway.

    Science.gov (United States)

    Huang, Ju-Yang; Ma, Yin-Zhong; Yuan, Yu-He; Zuo, Wei; Chu, Shi-Feng; Liu, Hang; Du, Guan-Hua; Zhang, Dong-Ming; Chen, Nai-Hong

    2016-09-01

    The persistence of neurogenesis raises the idea that neurons produced by the resident or transplanted neural stem cells could replace the neurons lost from brain injury or neurodegenerative disease. Therefore, compounds or methods for promoting neuronal differentiation become the focus of neurodegenerative disease therapy research. Claulansine F (Clau F), a newly discovered carbazole alkaloid, has been showed to induce neuritogenesis in PC12 cells. Herein, we studied the effect of Clau F on neuronal differentiation of neural stem/progenitor cells (NS/PCs). The current study demonstrated that Clau F initiated neuronal differentiation with a significant increase of TuJ1-positive cells and TuJ1 protein levels. We also found that Clau F promoted the maturity and sustainability of neurons by increasing MAP2-positive cells and MAP2 protein levels. At the same time, Clau F significantly inhibited the proliferation of NS/PCs. The underlying mechanism of Clau F was preliminary explored. Clau F treatment resulted in a profound increase of phosphorylation of Akt and GSK-3β, which led to GSK-3β inhibition and subsequently the nuclear accumulation of β-catenin. Further, the interaction between β-catenin and p300 in the nucleus was enhanced and the transcription of p300/β-catenin responsive genes were increased significantly (c-jun, fra-1) by Clau F. Importantly, the positive effect of Clau F on neuronal differentiation was abolished by Akti-1/2, a specific inhibitor of Akt-1/2 kinase, which indicated the involvement of Akt/GSK-3β in Clau F-mediated neuronal differentiation. In conclusion, these data suggested that Clau F promoted neuronal differentiation through Akt/GSK-3β/β-catenin signaling pathway in NS/PCs.

  9. Mesenchymal stem cells suppress lung inflammation and airway remodeling in chronic asthma rat model via PI3K/Akt signaling pathway

    OpenAIRE

    Lin, Hai-Yan; Xu, Lei; Xie, Shuan-shuan; Yu, Fei; Hu, Hai-Yang; Song, Xiao-lian; Wang, Chang-Hui

    2015-01-01

    Background: Mesenchymal stem cells (MSCs) came out to attract wide attention and had become one of the hotspots of most diseases’ research in decades. But at present, the mechanisms of how MSCs work on chronic asthma remain undefined. Our study aims at verifying whether MSCs play a role in preventing inflammation and airway remodeling via PI3K/AKT signaling pathway in the chronic asthma rats model. Methods: First, an ovalbumin (OVA)-induced asthma model was built. MSCs were administered to ov...

  10. Homing of circulating blood endothelial progenitor cells after myocardial infarction is mediated by Akt-SDF-1-signal pathway

    Institute of Scientific and Technical Information of China (English)

    赵岚

    2013-01-01

    Objective To investigate the expressions of protein kinase B(Akt) and stromal cell-derived factor-1(SDF-1) and their relations with circulating blood endothelial progenitor cell homing after myocardial infarction(MI). Methods MI was induced in the

  11. Novel PI3K/Akt inhibitors screened by the cytoprotective function of human immunodeficiency virus type 1 Tat.

    Directory of Open Access Journals (Sweden)

    Yuri Kim

    Full Text Available The PI3K/Akt pathway regulates various stress-related cellular responses such as cell survival, cell proliferation, metabolism and protein synthesis. Many cancer cell types display the activation of this pathway, and compounds inhibiting this cell survival pathway have been extensively evaluated as anti-cancer agents. In addition to cancers, several human viruses, such as HTLV, HPV, HCV and HIV-1, also modulate this pathway, presumably in order to extend the life span of the infected target cells for productive viral replication. The expression of HIV-1 Tat protein exhibited the cytoprotective effect in macrophages and a human microglial cell line by inhibiting the negative regulator of this pathway, PTEN. This cytoprotective effect of HIV-1 appears to contribute to the long-term survival and persistent HIV-1 production in human macrophage reservoirs. In this study we exploited the PI3K/Akt dependent cytoprotective effect of Tat-expressing CHME5 cells. We screened a collection of compounds known to modulate inflammation, and identified three novel compounds: Lancemaside A, Compound K and Arctigenin that abolished the cytoprotective phenotype of Tat-expressing CHME5 cells. All three compounds antagonized the kinase activity of Akt. Further detailed signaling studies revealed that each of these three compounds targeted different steps of the PI3K/Akt pathway. Arctigenin regulates the upstream PI3K enzyme from converting PIP2 to PIP3. Lancemaside A1 inhibited the movement of Akt to the plasma membrane, a critical step for Akt activation. Compound K inhibited Akt phosphorylation. This study supports that Tat-expressing CHME5 cells are an effective model system for screening novel PI3K/Akt inhibitors.

  12. Black raspberry extracts inhibit benzo(a)pyrene diol-epoxide-induced activator protein 1 activation and VEGF transcription by targeting the phosphotidylinositol 3-kinase/Akt pathway.

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    Huang, Chuanshu; Li, Jingxia; Song, Lun; Zhang, Dongyun; Tong, Qiangsong; Ding, Min; Bowman, Linda; Aziz, Robeena; Stoner, Gary D

    2006-01-01

    Previous studies have shown that freeze-dried black raspberry extract fractions inhibit benzo(a)pyrene [B(a)P]-induced transformation of Syrian hamster embryo cells and benzo(a)pyrene diol-epoxide [B(a)PDE]-induced activator protein-1 (AP-1) activity in mouse epidermal Cl 41 cells. The phosphotidylinositol 3-kinase (PI-3K)/Akt pathway is critical for B(a)PDE-induced AP-1 activation in mouse epidermal Cl 41 cells. In the present study, we determined the potential involvement of PI-3K and its downstream kinases on the inhibition of AP-1 activation by black raspberry fractions, RO-FOO3, RO-FOO4, RO-ME, and RO-DM. In addition, we investigated the effects of these fractions on the expression of the AP-1 target genes, vascular endothelial growth factor (VEGF) and inducible nitric oxide synthase (iNOS). Pretreatment of Cl 41 cells with fractions RO-F003 and RO-ME reduced activation of AP-1 and the expression of VEGF, but not iNOS. In contrast, fractions RO-F004 and RO-DM had no effect on AP-1 activation or the expression of either VEGF or iNOS. Consistent with inhibition of AP-1 activation, the RO-ME fraction markedly inhibited activation of PI-3K, Akt, and p70 S6 kinase (p70(S6k)). In addition, overexpression of the dominant negative PI-3K mutant delta p85 reduced the induction of VEGF by B(a)PDE. It is likely that the inhibitory effects of fractions RO-FOO3 and RO-ME on B(a)PDE-induced AP-1 activation and VEGF expression are mediated by inhibition of the PI-3K/Akt pathway. In view of the important roles of AP-1 and VEGF in tumor development, one mechanism for the chemopreventive activity of black raspberries may be inhibition of the PI-3K/Akt/AP-1/VEGF pathway. PMID:16397275

  13. MiR-34a targets GAS1 to promote cell proliferation and inhibit apoptosis in papillary thyroid carcinoma via PI3K/Akt/Bad pathway

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    Ma, Yanfei; Qin, Huadong [Department of Fourth Surgery, the Second Affiliated Hospital of Harbin Medical University, 148 Xuefu Road, Nangang District, Harbin 150086 (China); Cui, Yunfu, E-mail: yfma77@126.com [Department of First Surgery, the Second Affiliated Hospital of Harbin Medical University, 148 Xuefu Road, Nangang District, Harbin 150086 (China)

    2013-11-29

    Highlights: •MiR-34a is up- and GAS1 is down-regulated in papillary thyroid carcinoma. •GAS1 is a direct target for miR-34a. •MiR-34a promotes PTC cells proliferation and inhibits apoptosis through PI3K/Akt/Bad pathway. -- Abstract: MicroRNAs (miRNAs) are fundamental regulators of cell proliferation, differentiation, and apoptosis, and are implicated in tumorigenesis of many cancers. MiR-34a is best known as a tumor suppressor through repression of growth factors and oncogenes. Growth arrest specific1 (GAS1) protein is a tumor suppressor that inhibits cancer cell proliferation and induces apoptosis through inhibition of RET receptor tyrosine kinase. Both miR-34a and GAS1 are frequently down-regulated in various tumors. However, it has been reported that while GAS1 is down-regulated in papillary thyroid carcinoma (PTC), miR-34a is up-regulated in this specific type of cancer, although their potential roles in PTC tumorigenesis have not been examined to date. A computational search revealed that miR-34a putatively binds to the 3′-UTR of GAS1 gene. In the present study, we confirmed previous findings that miR-34a is up-regulated and GAS1 down-regulated in PTC tissues. Further studies indicated that GAS1 is directly targeted by miR-34a. Overexpression of miR-34a promoted PTC cell proliferation and colony formation and inhibited apoptosis, whereas knockdown of miR-34a showed the opposite effects. Silencing of GAS1 had similar growth-promoting effects as overexpression of miR-34a. Furthermore, miR-34a overexpression led to activation of PI3K/Akt/Bad signaling pathway in PTC cells, and depletion of Akt reversed the pro-growth, anti-apoptotic effects of miR-34a. Taken together, our results demonstrate that miR-34a regulates GAS1 expression to promote proliferation and suppress apoptosis in PTC cells via PI3K/Akt/Bad pathway. MiR-34a functions as an oncogene in PTC.

  14. Effects of simulated microgravity on human umbilical vein endothelial cell angiogenesis and role of the PI3K-Akt-eNOS signal pathway.

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    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. Black raspberry extracts inhibit benzo(a)pyrene diol-epoxide-induced activator protein 1 activation and VEGF transcription by targeting the phosphotidylinositol 3-kinase/Akt pathway.

    Science.gov (United States)

    Huang, Chuanshu; Li, Jingxia; Song, Lun; Zhang, Dongyun; Tong, Qiangsong; Ding, Min; Bowman, Linda; Aziz, Robeena; Stoner, Gary D

    2006-01-01

    Previous studies have shown that freeze-dried black raspberry extract fractions inhibit benzo(a)pyrene [B(a)P]-induced transformation of Syrian hamster embryo cells and benzo(a)pyrene diol-epoxide [B(a)PDE]-induced activator protein-1 (AP-1) activity in mouse epidermal Cl 41 cells. The phosphotidylinositol 3-kinase (PI-3K)/Akt pathway is critical for B(a)PDE-induced AP-1 activation in mouse epidermal Cl 41 cells. In the present study, we determined the potential involvement of PI-3K and its downstream kinases on the inhibition of AP-1 activation by black raspberry fractions, RO-FOO3, RO-FOO4, RO-ME, and RO-DM. In addition, we investigated the effects of these fractions on the expression of the AP-1 target genes, vascular endothelial growth factor (VEGF) and inducible nitric oxide synthase (iNOS). Pretreatment of Cl 41 cells with fractions RO-F003 and RO-ME reduced activation of AP-1 and the expression of VEGF, but not iNOS. In contrast, fractions RO-F004 and RO-DM had no effect on AP-1 activation or the expression of either VEGF or iNOS. Consistent with inhibition of AP-1 activation, the RO-ME fraction markedly inhibited activation of PI-3K, Akt, and p70 S6 kinase (p70(S6k)). In addition, overexpression of the dominant negative PI-3K mutant delta p85 reduced the induction of VEGF by B(a)PDE. It is likely that the inhibitory effects of fractions RO-FOO3 and RO-ME on B(a)PDE-induced AP-1 activation and VEGF expression are mediated by inhibition of the PI-3K/Akt pathway. In view of the important roles of AP-1 and VEGF in tumor development, one mechanism for the chemopreventive activity of black raspberries may be inhibition of the PI-3K/Akt/AP-1/VEGF pathway.

  16. 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.

  17. Fucoidan from seaweed Fucus vesiculosus inhibits migration and invasion of human lung cancer cell via PI3K-Akt-mTOR pathways.

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    Hyunkyoung Lee

    Full Text Available BACKGROUND: Recently there has been an increased interest in the pharmacologically active natural products associated with remedies of various kinds of diseases, including cancer. Fucoidan is a polysaccharide derived from brown seaweeds and has long been used as an ingredient in some dietary supplement products. Although fucoidan has been known to have anti-cancer activity, the anti-metastatic effects and its detailed mechanism of actions have been poorly understood. Therefore, the aims of this study were to demonstrate the anti-metastatic functions of fucoidan and its mechanism of action using A549, a highly metastatic human lung cancer cell line. METHODS AND PRINCIPAL FINDINGS: Fucoidan inhibits the growth of A549 cells at the concentration of 400 µg/ml. Fucoidan treatment of non-toxic dose (0-200 µg/ml exhibits a concentration-dependent inhibitory effect on the invasion and migration of the cancer cell via decreasing its MMP-2 activity. To know the mechanism of these inhibitory effects, Western blotting was performed. Fucoidan treatment down-regulates extracellular signal-related kinase 1 and 2 (ERK1/2 and phosphoinositide 3-kinase (PI3K-Akt-mammalian target of rapamycin (PI3K-Akt-mTOR pathways. Furthermore, fucoidan decreases the cytosolic and nuclear levels of Nuclear Factor-kappa B (p65. CONCLUSIONS/SIGNIFICANCE: The present study suggests that fucoidan exhibits anti-metastatic effect on A549 lung cancer cells via the down-regulation of ERK1/2 and Akt-mTOR as well as NF-kB signaling pathways. Hence, fucoidan can be considered as a potential therapeutic reagent against the metastasis of invasive human lung cancer cells.

  18. Anti-adipogenic effect of epiberberine is mediated by regulation of the Raf/MEK1/2/ERK1/2 and AMPKα/Akt pathways.

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    Choi, Jae Sue; Kim, Ji-Hye; Ali, Md Yousof; Jung, Hee Jin; Min, Byung-Sun; Choi, Ran Joo; Kim, Gun-Do; Jung, Hyun Ah

    2015-12-01

    It has been reported that alkaloids derived from Coptis chinensis exert anti-adipogenic activity on 3T3-L1 adipocytes by downregulating peroxisome proliferation-activity receptor-γ (PPAR-γ) and CCAAT/enhancer binding protein-α (C/EBP-α). However, the signaling-based mechanism of the inhibitory role of epiberberine in the early stages of 3T3-L1 adipocyte differentiation is uncharacterized. Here, we show that epiberberine had inhibitory effects on adipocyte differentiation and significantly decreased lipid accumulation by downregulating an adipocyte-specific transcription factor, sterol regulatory element-binding protein-1 (SREBP-1). Furthermore, we observed that epiberberine markedly suppressed the differentiation-mediated phosphorylation of components of both the Raf/mitogen-activated protein kinase 1 (MEK1)/extracellular signal-regulated protein kinase 1/2 (ERK1/2) and AMP-activated protein kinase-α1 (AMPKα)/Akt pathways. In addition, gene expression of fatty acid synthase (FAS) was significantly inhibited by treatment with epiberberine during adipogenesis. These results indicate that the anti-adipogenic mechanism of epiberberine is associated with inhibition of phosphorylation of Raf/MEK1/ERK1/2 and AMPKα/Akt, followed by downregulation of the major transcription factors of adipogenesis, such as PPAR-γ, C/EBP-α, and SREBP-1, and FAS. Taken together, this study suggests that the anti-adipogenic effect of epiberberine is mediated by downregulation of the Raf/MEK1/ERK1/2 and AMPKα/Akt pathways during 3T3-L1 adipocyte differentiation. Moreover, the anti-adipogenic effects of epiberberine were not accompanied by modulation of β-catenin.

  19. Cinnamaldehyde affects the biological behavior of human colorectal cancer cells and induces apoptosis via inhibition of the PI3K/Akt signaling pathway.

    Science.gov (United States)

    Li, Jiepin; Teng, Yuhao; Liu, Shenlin; Wang, Zifan; Chen, Yan; Zhang, Yingying; Xi, Songyang; Xu, Song; Wang, Ruiping; Zou, Xi

    2016-03-01

    Cinnamaldehyde (CA) is a bioactive compound isolated from the stem bark of Cinnamomum cassia, that has been identified as an antiproliferative substance with pro-apoptotic effects on various cancer cell lines in vitro. In the present study, the effects of CA on human colon cancer cells were investigated at both the molecular and cellular levels. Three types of colorectal cancer cells at various stages of differentiation and invasive ability (SW480, HCT116 and LoVo) were treated with CA at final concentrations of 20, 40 and 80 µg/ml for 24 h. Compared with the control group, the proliferation inhibition rate of the human colorectal cancer cells following treatment with CA increased in a dose- and time-dependent manner. The invasion and adhesion abilities of the cells were significantly inhibited as indicated by Transwell and cell-matrix adhesion assays. Meanwhile, CA also upregulated the expression of E-cadherin and downregulated the expression of matrix metalloproteinase-2 (MMP-2) and MMP-9. CA also elevated the apoptotic rate. The levels of pro-apoptotic genes were upregulated while the levels of apoptosis inhibitory genes were decreased which further confirmed the pro-apoptotic effect of CA. In order to explore the mechanism of CA-induced apoptosis, insulin-like growth factor-1 (IGF-1) and PI3K inhibitor (LY294002) were used to regulate the phosphoinositide 3-kinase (PI3K)/AKT pathway. The transcription activity of PI3K/AKT was markedly inhibited by CA, as well as IGF-1 which functions as an anti-apoptotic factor. In conclusion, CA has the potential to be developed as a new antitumor drug. The mechanisms of action involve the regulation of expression of genes involved in apoptosis, invasion and adhesion via inhibition of the PI3K/Akt signaling pathway. PMID:26677144

  20. Hibiscus sabdariffa Leaf Extract Inhibits Human Prostate Cancer Cell Invasion via Down-Regulation of Akt/NF-kB/MMP-9 Pathway.

    Science.gov (United States)

    Chiu, Chun-Tang; Chen, Jing-Hsien; Chou, Fen-Pi; Lin, Hui-Hsuan

    2015-07-01

    Hibiscus sabdariffa leaf has been previously shown to possess hypoglycemic, hypolipidemic, and antioxidant effects, and induce tumor cell apoptosis. However, the molecular mechanisms involved in the anticancer activity of H. sabdariffa leaf extract (HLE) are poorly understood. The object of the study was to examine the anti-invasive potential of HLE. First, HLE was demonstrated to be rich in polyphenols. The results of wound-healing assay and in vitro transwell assay revealed that HLE dose-dependently inhibited the migration and invasion of human prostate cancer LNCaP (lymph node carcinoma of the prostate) cells under non-cytotoxic concentrations. Our results further showed that HLE exerted an inhibitory effect on the activity and expressions of matrix metalloproteinase-9 (MMP-9). The HLE-inhibited MMP-9 expression appeared to be a consequence of nuclear factor-kappaB (NF-κB) inactivation because its DNA-binding activity was suppressed by HLE. Molecular data showed all these influences of HLE might be mediated via inhibition of protein kinase B (PKB, also known as Akt)/NF-kB/MMP-9 cascade pathway, as demonstrated by the transfection of Akt1 overexpression vector. Finally, the inhibitory effect of HLE was proven by its inhibition on the growth of LNCaP cells and the expressions of metastasis-related molecular proteins in vivo. These findings suggested that the inhibition of MMP-9 expression by HLE may act through the suppression of the Akt/NF-kB signaling pathway, which in turn led to the reduced invasiveness of the cancer cells. PMID:26115086

  1. Piperlongumine induces apoptosis and autophagy in human lung cancer cells through inhibition of PI3K/Akt/mTOR pathway.

    Science.gov (United States)

    Wang, Feng; Mao, Yong; You, Qingjun; Hua, Dong; Cai, Dongyan

    2015-09-01

    Piperlongumine (PL), a natural alkaloid present in the fruit of the Long pepper, is known to exhibit notable anti-cancer effects. Nonetheless, the anti-tumor effect of PL in lung cancer cells still remains unclear. In the present study, we reported the chemotherapeutic effects of PL using in vitro and in vivo models. We showed that PL displayed potent anti-neoplastic activity against lung cancer A549 cells as well as corresponding docetaxel-resistant A549/DTX cells. In addition, we found that PL induced apoptosis in both A549 and A549/DTX cells. PL also induced autophagy in A549/DTX cells. Moreover, autophagy-specific inhibitors (3-methyladenine) or Beclin1 and Atg 5 small interfering RNAs (siRNAs) enhanced PL-induced apoptosis, indicating that PL-mediated autophagy may protect A549/DTX cells from undergoing apoptotic cell death. Furthermore, we observed the inhibition of phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway by PL. Finally, PL inhibited the growth of A549/DTX xenograft tumors, which was associated with inhibition of cell proliferation, induction of apoptosis of tumor cells and decreased expression of p-Akt and p-mTOR in tumor xenograft tissues. In summary, our study demonstrated that PL induced apoptosis and autophagy through modulation of the PI3K/Akt/mTOR pathway in human lung cancer cells. This study may provide a rationale for future clinical application using PL as a chemotherapeutic agent for lung cancer. PMID:26246196

  2. Crosstalk between Meg3 and miR-1297 regulates growth of testicular germ cell tumor through PTEN/PI3K/AKT pathway.

    Science.gov (United States)

    Yang, Nian-Qin; Luo, Xiao-Jin; Zhang, Jian; Wang, Guo-Min; Guo, Jian-Ming

    2016-01-01

    Maternally Expressed Gene 3 (Meg3) encodes a long non-coding RNA that has been recently shown to regulate tumorigenesis through its interaction with microRNA (miR). We have recently reported that miR-1297 might play a role in the regulation of PTEN/PI3k/Akt signaling pathway in testicular germ cell tumor (TGCT). However, a crosstalk between Meg3 and miR-1297 in TGCT has not been appreciated. Here, we analyzed the levels of Meg3, miR-1297 and PTEN in TGCT specimens, compared to paired adjacent non-tumor tissue (NT), and found that Meg3 levels were significantly decreased and miR-1297 levels were unchanged in TGCT. PTEN protein but not mRNA levels significantly decreased in TGCT. Bioinformatics analyses showed that miR-1297 bound to 3'-UTR of PTEN mRNA, while miR-1297 also bound to Meg3. Luciferase report assay showed that Meg3 overexpression abolished the effects of miR-1297 on 3'-UTR of PTEN mRNA, possibly through competitive binding, which was supported by double fluorescent in situ hybridization showing co-localization of intracellular Meg3 and miR-1297 signals in TGCT cells. Moreover, Meg3 overexpression abolished the inhibitory effects of miR-1297 on PTEN, resulting in deactivation of Akt and decreases in cell growth. Together, these data demonstrate a previous unappreciated pathway in which Crosstalk between Meg3 and miR-1297 regulates growth of TFCT through PTEN/PI3K/AKT signaling. Re-expression of Meg3 may be an attractive strategy for TGCT therapy. PMID:27158395

  3. The Akt/mTOR/p70S6K pathway is activated in IgA nephropathy and rapamycin may represent a viable treatment option.

    Science.gov (United States)

    Tian, Jihua; Wang, Yanhong; Guo, Haixiu; Li, Rongshan

    2015-12-01

    IgA nephropathy (IgAN) is one of the most frequent forms of glomerulonephritis, and 20 to 40% of patients progress to end-stage renal disease (ESRD) within 20 years of disease onset. However, little is known about the molecular pathways involved in the altered physiology of mesangial cells during IgAN progression. This study was designed to explore the role of mTOR signaling and the potential of targeted rapamycin therapy in a rat model of IgAN. After establishing an IgA nephropathy model, the rats were randomly divided into four groups: control, control+rapamycin, IgAN and IgA+rapamycin. Western blotting and immunohistochemistry were performed to determine phospho-Akt, p70S6K and S6 protein levels. Coomassie Brilliant Blue was utilized to measure 24-h urinary protein levels. The biochemical parameters of the rats were analyzed with an autoanalyzer. To evaluate IgA deposition in the glomeruli, FITC-conjugated goat anti-rat IgA antibody was used for direct immunofluorescence. Cellular proliferation and the mesangial matrix in glomeruli were assayed via histological and morphometric procedures. Our results showed that p70S6K, S6 and Akt phosphorylation were significantly upregulated in IgAN rats, and rapamycin effectively inhibited p70S6K and S6 phosphorylation. A low dose of the mTOR inhibitor rapamycin reduced proteinuria, inhibited IgA deposition, and protected kidney function in an IgAN rat model. Low-dose rapamycin treatment corresponded to significantly lower cellular proliferation rates and a decreased mesangial matrix in the glomeruli. In conclusion, the Akt/mTOR/p70S6K pathway was activated in IgAN, and our findings suggested that rapamycin may represent a viable option for the treatment of IgAN. PMID:26297427

  4. The Effects of Xiangqing Anodyne Spray on Treating Acute Soft-Tissue Injury Mainly Depend on Suppressing Activations of AKT and p38 Pathways

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    Shudong Wang

    2016-01-01

    Full Text Available Objectives. In the present study we try to elucidate the mechanism of Xiangqing anodyne spray (XQAS effects on acute soft-tissue injury (STI. Methods. Acute STI model was established by hammer blow in the rat hind leg muscle. Within 8 hours, instantly after modeling and per 2-hour interval repeated topical applications with or without XQAS, CP or IH ethanol extracts spray (CPS and IHS were performed, respectively; muscle swelling rate and inflammation-related biochemical parameters, muscle histological observation, and mRNA and protein expression were then examined. Results. XQAS dose-dependently suppressed STI-caused muscle swelling, proinflammatory mediator productions, and oxidative stress as well as severe pathological changes in the injured muscle tissue. Moreover, CPS mainly by blocking p38 activation while IHS majorly by blocking AKT activation led to cytoplastic IκBα degradation with NF-κB p65 translocated into the nucleus. There are synergistic effects between CP and IH components in the XQAS on preventing from acute STI with suppressing IκBα degradation, NF-κB p65 translocation, and subsequent inflammation and oxidative stress-related abnormality. Conclusion. Marked effects of XQAS on treating acute STI are ascribed to strong anti-inflammatory and antioxidative actions with a reasonable combination of CP active components, blocking p38-NF-κB pathway activated, and IH active components, blocking AKT-NF-κB pathway activated.

  5. Soy Isoflavones Regulate Lipid Metabolism through an AKT/mTORC1 Pathway in Diet-Induced Obesity (DIO Male Rats

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    Chao Huang

    2016-05-01

    Full Text Available The pandemic tendency of obesity and its strong association with serious co-morbidities have elicited interest in the underlying mechanisms of these pathologies. Lipid homeostasis, closely involved in obesity, has been reported to be regulated by multiple pathways. mTORC1 is emerging as a critical regulator of lipid metabolism. Here, we describe that the consumption of soy isoflavones, with a structural similarity to that of estradiol, could mitigate obesity through an AKT/mTORC1 pathway. Fed with soy isoflavones, the diet-induced obesity (DIO male rats exhibited decreased body weight, accompanied with suppressed lipogenesis and adipogenesis, as well as enhanced lipolysis and β‑oxidation. The phosphorylation of AKT and S6 were decreased after soy isoflavone treatment in vivo and in vitro, suggesting an inhibition effect of soy isoflavones on mTORC1 activity. Our study reveals a potential mechanism of soy isoflavones regulating lipid homeostasis, which will be important for obesity treatment.

  6. 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

    2015-01-01

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

  7. 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.

  8. DSePA Antagonizes High Glucose-Induced Neurotoxicity: Evidences for DNA Damage-Mediated p53 Phosphorylation and MAPKs and AKT Pathways.

    Science.gov (United States)

    Wang, Kun; Fu, Xiao-Yan; Fu, Xiao-Ting; Hou, Ya-Jun; Fang, Jie; Zhang, Shuai; Yang, Ming-Feng; Li, Da-Wei; Mao, Lei-Lei; Sun, Jing-Yi; Yuan, Hui; Yang, Xiao-Yi; Fan, Cun-Dong; Zhang, Zong-Yong; Sun, Bao-Liang

    2016-09-01

    Hyperglycemia as the major hallmark of diabetic neuropathy severely limited its therapeutic efficiency. Evidences have revealed that selenium (Se) as an essential trace element could effectively reduce the risk of neurological diseases. In the present study, 3,3'-diselenodipropionic acid (DSePA), a derivative of selenocystine, was employed to investigate its protective effect against high glucose-induced neurotoxicity in PC12 cells and evaluate the underlying mechanism. The results suggested that high glucose showed significant cytotoxicity through launching mitochondria-mediated apoptosis in PC12 cells, accompanied by poly (ADP-ribose) polymerase (PARP) cleavage, caspase activation, and mitochondrial dysfunction. Moreover, high glucose also triggered DNA damage and dysregulation of MAPKs and AKT pathways through reactive oxygen species (ROS) overproduction. p53 RNA interference partially suppressed high glucose-induced cytotoxicity and apoptosis, indicating the role of p53 in high glucose-induced signal. However, DSePA pretreatment effectively attenuated high glucose-induced cytotoxicity, inhibited the mitochondrial dysfunction through regulation of Bcl-2 family, and ultimately reversed high glucose-induced apoptotic cell death in PC12 cells. Attenuation of caspase activation, PARP cleavage, DNA damage, and ROS accumulation all confirmed its protective effects. Moreover, DSePA markedly alleviated the dysregulation of AKT and MAPKs pathways induced by high glucose. Our findings revealed that the strategy of using DSePA to antagonize high glucose-induced neurotoxicity may be a highly effective strategy in combating high glucose-mediated neurological diseases. PMID:26232068

  9. Interleukin-21 promotes osteoclastogenesis in RAW264.7 cells through the PI3K/AKT signaling pathway independently of RANKL.

    Science.gov (United States)

    Xing, Rui; Zhang, Yingjian; Li, Changhong; Sun, Lin; Yang, Lin; Zhao, Jinxia; Liu, Xiangyuan

    2016-10-01

    Cytokines play a key role in the bone destruction of rheumatoid arthritis (RA). Interleukin-21 (IL-21) promotes osteoclastogenesis in RA in a receptor activator of nuclear factor-κB ligand (RANKL)-dependent way. Whether IL-21 is capable of promoting osteoclastogenesis directly in the absence of RANKL remains unknown. In the present study, we examined the osteoclastogenic activity of IL-21 in RAW264.7 cells in the absence of RANKL. We found that IL-21 enhanced osteoclastogenesis and this was demonstrated by increased numbers of tartrate-resistant acid phosphatase (TRAP)-positive stained, multinucleated cells compared with the negative control. Western blot analysis and immunocytochemistry showed the positive expression of calcitonin receptor (CTR) in the IL-21 group. RT-PCR and RT-qPCR also verified the increased mRNA expression of CTR and cathepsin K in the IL-21 group compared with the negative control. The scanning electronic microscope images showed a few resorption pits on the bone slices cultured with IL-21. The phosphoinositide 3-kinase (PI3K)/AKT pathway inhibitor LY294002 significantly suppressed IL-21-induced osteoclastogenesis. Taken together, these findings suggest that IL-21 has direct osteoclastogenic potential independently of RANKL. IL-21 may promote osteoclastogenesis through the PI3K/AKT signaling pathway. Therapy targeting IL-21 may be of value in preventing bone erosions in patients with RA. PMID:27599586

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

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    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.

  11. Arctigenin, a Potent Ingredient of Arctium lappa L., Induces Endothelial Nitric Oxide Synthase and Attenuates Subarachnoid Hemorrhage-Induced Vasospasm through PI3K/Akt Pathway in a Rat Model.

    Science.gov (United States)

    Chang, Chih-Zen; Wu, Shu-Chuan; Chang, Chia-Mao; Lin, Chih-Lung; Kwan, Aij-Lie

    2015-01-01

    Upregulation of protein kinase B (PKB, also known as Akt) is observed within the cerebral arteries of subarachnoid hemorrhage (SAH) animals. This study is of interest to examine Arctigenin, a potent antioxidant, on endothelial nitric oxide synthase (eNOS) and Akt pathways in a SAH in vitro study. Basilar arteries (BAs) were obtained to examine phosphatidylinositol-3-kinase (PI3K), phospho-PI3K, Akt, phospho-Akt (Western blot) and morphological examination. Endothelins (ETs) and eNOS evaluation (Western blot and immunostaining) were also determined. Arctigenin treatment significantly alleviates disrupted endothelial cells and tortured internal elastic layer observed in the SAH groups (p < 0.01). The reduced eNOS protein and phospho-Akt expression in the SAH groups were relieved by the treatment of Arctigenin (p < 0.01). This result confirmed that Arctigenin might exert dural effects in preventing SAH-induced vasospasm through upregulating eNOS expression via the PI3K/Akt signaling pathway and attenuate endothelins after SAH. Arctigenin shows therapeutic promise in the treatment of cerebral vasospasm following SAH.

  12. Arctigenin, a Potent Ingredient of Arctium lappa L., Induces Endothelial Nitric Oxide Synthase and Attenuates Subarachnoid Hemorrhage-Induced Vasospasm through PI3K/Akt Pathway in a Rat Model

    Directory of Open Access Journals (Sweden)

    Chih-Zen Chang

    2015-01-01

    Full Text Available Upregulation of protein kinase B (PKB, also known as Akt is observed within the cerebral arteries of subarachnoid hemorrhage (SAH animals. This study is of interest to examine Arctigenin, a potent antioxidant, on endothelial nitric oxide synthase (eNOS and Akt pathways in a SAH in vitro study. Basilar arteries (BAs were obtained to examine phosphatidylinositol-3-kinase (PI3K, phospho-PI3K, Akt, phospho-Akt (Western blot and morphological examination. Endothelins (ETs and eNOS evaluation (Western blot and immunostaining were also determined. Arctigenin treatment significantly alleviates disrupted endothelial cells and tortured internal elastic layer observed in the SAH groups (p<0.01. The reduced eNOS protein and phospho-Akt expression in the SAH groups were relieved by the treatment of Arctigenin (p<0.01. This result confirmed that Arctigenin might exert dural effects in preventing SAH-induced vasospasm through upregulating eNOS expression via the PI3K/Akt signaling pathway and attenuate endothelins after SAH. Arctigenin shows therapeutic promise in the treatment of cerebral vasospasm following SAH.

  13. An Integrative Pathway-based Clinical-genomic Model for Cancer Survival Prediction.

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    Chen, Xi; Wang, Lily; Ishwaran, Hemant

    2010-09-01

    Prediction models that use gene expression levels are now being proposed for personalized treatment of cancer, but building accurate models that are easy to interpret remains a challenge. In this paper, we describe an integrative clinical-genomic approach that combines both genomic pathway and clinical information. First, we summarize information from genes in each pathway using Supervised Principal Components (SPCA) to obtain pathway-based genomic predictors. Next, we build a prediction model based on clinical variables and pathway-based genomic predictors using Random Survival Forests (RSF). Our rationale for this two-stage procedure is that the underlying disease process may be influenced by environmental exposure (measured by clinical variables) and perturbations in different pathways (measured by pathway-based genomic variables), as well as their interactions. Using two cancer microarray datasets, we show that the pathway-based clinical-genomic model outperforms gene-based clinical-genomic models, with improved prediction accuracy and interpretability.

  14. Sericin can reduce hippocampal neuronal apoptosis by activating the Akt signal transduction pathway in a rat model of diabetes mellitus☆

    OpenAIRE

    Chen, Zhihong; He, Yaqiang; Song, Chengjun; Dong, Zhijun; Su, Zhejun; Xue, Jingfeng

    2012-01-01

    In the present study, a rat model of type 2 diabetes mellitus was established by continuous peritoneal injection of streptozotocin. Following intragastric perfusion of sericin for 35 days, blood glucose levels significantly reduced, neuronal apoptosis in the hippocampal CA1 region decreased, hippocampal phosphorylated Akt and nuclear factor kappa B expression were enhanced, but Bcl-xL/Bcl-2 associated death promoter expression decreased. Results demonstrated that sericin can reduce hippocampa...

  15. Matrine inhibits the growth and induces apoptosis of osteosarcoma cells in vitro by inactivating the Akt pathway.

    Science.gov (United States)

    Xu, Gong-Ping; Zhao, Wei; Zhuang, Jin-Peng; Zu, Jia-Ning; Wang, Duan-Yang; Han, Fei; Zhang, Zhi-Peng; Yan, Jing-Long

    2015-03-01

    Matrine, a natural product, has been demonstrated to be a promising chemotherapeutic drug for some cancers. Using flow cytometric analysis of the cell cycle and apoptosis, we found that matrine inhibited the proliferation and induced apoptosis in the human osteosarcoma (OS) cell lines MG63, HOS, U2OS, and SAOS2 in vitro in a dose-dependent manner. We therefore assessed the role of the serine/threonine kinase Akt in the regulation of matrine-mediated cell growth inhibition and apoptosis induction in human OS cell lines. After treatment for 48 h, matrine induced G0/G1-stage cell cycle arrest in MG63, U2OS, and SAOS2 cells associated with an increase in the expression of p27(Kip1) and a decrease in the expression of Akt, glycogen synthase kinase 3 (GSK3)-β (Ser9), and cyclin D1. Furthermore, the pro-apoptotic factor Bax was upregulated. Overall, our findings suggest that matrine may be an effective anti-osteosarcoma drug due to its ability to inhibit proliferation and induce apoptosis in OS cells, possibly through the involvement of Akt signaling.

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

    Science.gov (United States)

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

    2016-01-01

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

  17. Synergistic effect of a combination of nanoparticulate Fe3O4 and gambogic acid on phosphatidylinositol 3-kinase/Akt/Bad pathway of LOVO cells

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    Hu S

    2012-07-01

    K, p-Akt, p-Bad, pro-caspase 9, and pro-caspase 3 degraded.Conclusion: Magnetic nanoparticles containing Fe3O4 can enhance apoptosis induced by gambogic acid which may be closely related to regulation of the PI3K/Akt/Bad pathway in the treatment of human colon cancer.Keywords: Fe3O4, magnetic nanoparticles, gambogic acid, LOVO cells, apoptosis, PI3K, Akt, Bad, pathway

  18. Embelin suppresses growth of human pancreatic cancer xenografts, and pancreatic cancer cells isolated from KrasG12D mice by inhibiting Akt and Sonic hedgehog pathways.

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    Minzhao Huang

    Full Text Available Pancreatic cancer is a deadly disease, and therefore effective treatment and/or prevention strategies are urgently needed. The objectives of this study were to examine the molecular mechanisms by which embelin inhibited human pancreatic cancer cell growth in vitro, and xenografts in Balb C nude mice, and pancreatic cancer cell growth isolated from KrasG12D transgenic mice. XTT assays were performed to measure cell viability. AsPC-1 cells were injected subcutaneously into Balb c nude mice and treated with embelin. Cell proliferation and apoptosis were measured by Ki67 and TUNEL staining, respectively. The expression of Akt, and Sonic Hedgehog (Shh and their target gene products were measured by the immunohistochemistry, and Western blot analysis. The effects of embelin on pancreatic cancer cells isolated from 10-months old KrasG12D mice were also examined. Embelin inhibited cell viability in pancreatic cancer AsPC-1, PANC-1, MIA PaCa-2 and Hs 766T cell lines, and these inhibitory effects were blocked either by constitutively active Akt or Shh protein. Embelin-treated mice showed significant inhibition in tumor growth which was associated with reduced expression of markers of cell proliferation (Ki67, PCNA and Bcl-2 and cell cycle (cyclin D1, CDK2, and CDK6, and induction of apoptosis (activation of caspase-3 and cleavage of PARP, and increased expression of Bax. In addition, embelin inhibited the expression of markers of angiogenesis (COX-2, VEGF, VEGFR, and IL-8, and metastasis (MMP-2 and MMP-9 in tumor tissues. Antitumor activity of embelin was associated with inhibition of Akt and Shh pathways in xenografts, and pancreatic cancer cells isolated from KrasG12D mice. Furthermore, embelin also inhibited epithelial-to-mesenchymal transition (EMT by up-regulating E-cadherin and inhibiting the expression of Snail, Slug, and ZEB1. These data suggest that embelin can inhibit pancreatic cancer growth, angiogenesis and metastasis by suppressing Akt and

  19. TIME COURSE CHANGE OF IGF1/AKT/MTOR/P70S6K PATHWAY ACTIVATION IN RAT GASTROCNEMIUS MUSCLE DURING REPEATED BOUTS OF ECCENTRIC EXERCISE

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    Eisuke Ochi

    2010-06-01

    Full Text Available The purpose of this study was to examine whether insulin-like growth factor (IGF-1 and Akt/mTOR/p70S6K pathway activity is altered by chronic eccentric exercise in rat medial gastrocnemius muscle. Male Wistar rats (n = 24 were randomly assigned to 1 of the 2 groups: eccentric exercise (ECC group or sham-operated control (CON group. Rats in the ECC group were trained every second day for 10 days (5 sessions in total or 20 days (10 sessions in total. After either 5 or 10 exercise sessions, muscle specimens were dissected and weighed. The mRNA expression of IGF-1 and its variant, mechano growth factor (MGF, was evaluated using real time reverse transcriptase-polymerase chain reaction (RT-PCR. Tissue concentrations of Akt (P, mTOR (P, and p70S6K (P were measured by using western blot analysis. The medial gastrocnemius muscle mass of the ECC group did not show any significant difference after 5 exercise sessions, whereas the muscle mass increased significantly after 10 exercise sessions with a concomitant increase in the cross-sectional area of muscle fibers (p < 0.05. The expression of IGF-1 mRNA and the tissue concentrations of Akt (P and p70S6K (P after 10 exercise sessions was significantly higher than those of the age-matched controls and the rats that received 5 exercise sessions. The expression of MGF mRNA in both ECC5S and ECC10S were significantly higher than that in each period-matched control (p < 0.01. The tissue concentration of mTOR (P after 10 sessions showed a significant increase when compared with period-matched controls (p < 0.01. These results suggest that activation of the IGF-1/Akt/mTOR/p70S6K signaling pathway becomes dominant in the later phase of chronic exercise, when significant muscular hypertrophy is observed

  20. PI3K and Akt as molecular targets for cancer therapy: current clinical outcomes

    Institute of Scientific and Technical Information of China (English)

    Ipsita PAL; Mahitosh MANDAL

    2012-01-01

    The PI3K-Akt pathway is a vital regulator of cell proliferation and survival.Alterations in the PIK3CA gene that lead to enhanced PI3K kinase activity have been reported in many human cancer types,including cancers of the colon,breast,brain,liver,stomach and lung.Deregulation of PI3K causes aberrant Akt activity.Therefore targeting this pathway could have implications for cancer treatment.The first generation PI3K-Akt inhibitors were proven to be highly effective with a low IC50,but later,they were shown to have toxic side effects and poor pharmacological properties and selectivity.Thus,these inhibitors were only effective in preclinical models.However,derivatives of these first generation inhibitors are much more selective and are quite effective in targeting the PI3K-Akt pathway,either alone or in combination.These second-generation inhibitors are essentially a specific chemical moiety that helps to form a strong hydrogen bond interaction with the PI3K/Akt molecule.The goal of this review is to delineate the current efforts that have been undertaken to inhibit the various components of the PI3K and Akt pathway in different types of cancer both in vitro and in vivo.Our focus here is on these novel therapies and their inhibitory effects that depend upon their chemical nature,as well as their development towards clinical trials.

  1. Research in anti oligodendrocytes apoptosis by activating PI3K/Akt signal pathway in preterm rat%激活 PI3K/Akt 信号通路抗少突胶质细胞凋亡的研究

    Institute of Scientific and Technical Information of China (English)

    帅春; 汪灏

    2014-01-01

    目的探讨在脑室周围白质软化的早产大鼠中,脑组织 PI3K/Akt 通路的磷酸化激活情况,以及神经生长因子是否有抗少突胶质细胞凋亡的作用。方法本实验研究在早产大鼠脑室周围白质软化后,脑组织中少突胶质细胞的凋亡情况。给予神经生长因子,比较脑组织中 Akt 磷酸化激活情况及相应少突胶质细胞凋亡改变。结果早产大鼠脑损伤后,脑组织中少突胶质细胞凋亡急剧增加,给予神经生长因子后,脑组织中 Akt 磷酸化激活明显增加,相应少突胶质细胞凋亡明显减少。结论神经生长因子对脑损伤的保护机制与其增强 PI3K/Akt 信号转导通路的激活有关,激活 PI3K/Akt 信号转导通路可防治脑损伤刺激后的少突胶质细胞的凋亡。%Objective To explore activating phosphorylation of PI3K/Akt pathway in brain tissue and whether nerve growth factor has the effect of anti oligodendrocytes apoptosis in preterm rat with periventricular leukomalacia. Methods We studied apoptotic oligodendrocytes in brain tissue of preterm rats with periventricular leukomalacia and compared the situation of Akt phosphorylation activation and oligodendrocytes apoptosis change accordingly after nerve growth factor administered. Re-sults Oligodendrocytes apoptosis increased sharply in brain tissue after premature rats suffering periventricular leukomalacia.Akt phosphorylation activation increased significantly in brain tissue and the corresponding oligodendrocytes apoptosis decreased significantly after nerve growth factor administerd. Conclusion The effects of nerve growth factor on brain injury protection mechanism were related with enhancing the activation of PI3K/Akt signal transduction pathway.The activation of PI3K/Akt sig-nal transduction pathway may prevent and treat apoptotic oligodendrocytes after brain injury.

  2. Neuronal AKAP150 coordinates PKA and Epac-mediated PKB/Akt phosphorylation

    NARCIS (Netherlands)

    Nijholt, Ingrid M.; Dolga, Amalia M.; Ostroveanu, Anghelus; Luiten, Paul G. M.; Schmidt, Martina; Eisel, Ulrich L. M.

    2008-01-01

    In diverse neuronal processes ranging from neuronal survival to synaptic plasticity cyclic adenosine monophosphate (cAMP)-dependent signaling is tightly connected with the protein kinase B (PKB)/Akt pathway but the precise nature of this connection remains unknown. In the current study we investigat

  3. The Nuclear Zinc Finger Protein Zfat Maintains FoxO1 Protein Levels in Peripheral T Cells by Regulating the Activities of Autophagy and the Akt Signaling Pathway.

    Science.gov (United States)

    Ishikura, Shuhei; Iwaihara, Yuri; Tanaka, Yoko; Luo, Hao; Nishi, Kensuke; Doi, Keiko; Koyanagi, Midori; Okamura, Tadashi; Tsunoda, Toshiyuki; Shirasawa, Senji

    2016-07-15

    Forkhead box O1 (FoxO1) is a key molecule for the development and functions of peripheral T cells. However, the precise mechanisms regulating FoxO1 expression in peripheral T cells remain elusive. We previously reported that Zfat(f/f)-CD4Cre mice showed a marked decline in FoxO1 protein levels in peripheral T cells, partially through proteasomal degradation. Here we have identified the precise mechanisms, apart from proteasome-mediated degradation, of the decreased FoxO1 levels in Zfat-deficient T cells. First, we confirmed that tamoxifen-inducible deletion of Zfat in Zfat(f/f)-CreERT2 mice coincidently decreases FoxO1 protein levels in peripheral T cells, indicating that Zfat is essential for maintaining FoxO1 levels in these cells. Although the proteasome-specific inhibitors lactacystin and epoxomicin only moderately increase FoxO1 protein levels, the inhibitors of lysosomal proteolysis bafilomycin A1 and chloroquine restore the decreased FoxO1 levels in Zfat-deficient T cells to levels comparable with those in control cells. Furthermore, Zfat-deficient T cells show increased numbers of autophagosomes and decreased levels of p62 protein, together indicating that Zfat deficiency promotes lysosomal FoxO1 degradation through autophagy. In addition, Zfat deficiency increases the phosphorylation levels of Thr-308 and Ser-473 of Akt and the relative amounts of cytoplasmic to nuclear FoxO1 protein levels, indicating that Zfat deficiency causes Akt activation, leading to nuclear exclusion of FoxO1. Our findings have demonstrated a novel role of Zfat in maintaining FoxO1 protein levels in peripheral T cells by regulating the activities of autophagy and the Akt signaling pathway. PMID:27226588

  4. Phosphatidylinositol 3-Kinase/AKT Pathway Inhibition by Doxazosin Promotes Glioblastoma Cells Death, Upregulation of p53 and Triggers Low Neurotoxicity.

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    Mariana Maier Gaelzer

    Full Text Available Glioblastoma is the most frequent and malignant brain tumor. Treatment includes chemotherapy with temozolomide concomitant with surgical resection and/or irradiation. However, a number of cases are resistant to temozolomide, as well as the human glioblastoma cell line U138-MG. We investigated doxazosin's (an antihypertensive drug activity against glioblastoma cells (C6 and U138-MG and its neurotoxicity on primary astrocytes and organoptypic hippocampal cultures. For this study, the following methods were used: citotoxicity assays, flow cytometry, western-blotting and confocal microscopy. We showed that doxazosin induces cell death on C6 and U138-MG cells. We observed that doxazosin's effects on the PI3K/Akt pathway were similar as LY294002 (PI3K specific inhibitor. In glioblastoma cells treated with doxasozin, Akt levels were greatly reduced. Upon examination of activities of proteins downstream of Akt we observed upregulation of GSK-3β and p53. This led to cell proliferation inhibition, cell death induction via caspase-3 activation and cell cycle arrest at G0/G1 phase in glioblastoma cells. We used in this study Lapatinib, a tyrosine kinase inhibitor, as a comparison with doxazosin because they present similar chemical structure. We also tested the neurocitotoxicity of doxazosin in primary astrocytes and organotypic cultures and observed that doxazosin induced cell death on a small percentage of non-tumor cells. Aggressiveness of glioblastoma tumors and dismal prognosis require development of new treatment agents. This includes less toxic drugs, more selective towards tumor cells, causing less damage to the patient. Therefore, our results confirm the potential of doxazosin as an attractive therapeutic antiglioma agent.

  5. Andrographolide inhibits growth of human T-cell acute lymphoblastic leukemia Jurkat cells by downregulation of PI3K/AKT and upregulation of p38 MAPK pathways

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    Yang T

    2016-04-01

    Full Text Available Tingfang Yang,1 Shuluan Yao,2 Xianfeng Zhang,3 Yan Guo2 1Department of Pediatrics, Jining No 1 People’s Hospital, Shandong Province, People’s Republic of China; 2Department of Respiratory Medicine, Jining Medical University Affiliated Hospital, Shandong Province, People’s Republic of China; 3Department of Psychiatry, Jining Psychiatric Hospital, Shandong Province, People’s Republic of China Abstract: T-cell acute lymphoblastic leukemia (T-ALL as a prevalent hematologic malignancy is one of the most common malignant tumors worldwide in children. Andrographolide (Andro, the major active component from Andrographis paniculata, has been shown to possess antitumor activities in several types of cancer cells. However, whether Andro would inhibit T-ALL cell growth remains unclear. In this study, we investigated the cytotoxic effect of Andro on human T-ALL Jurkat cells and explored the mechanisms of cell death. Cell apoptosis was assayed by flow cytometry, and the signaling transduction for Andro was analyzed by Western blotting. The results indicated 10 µg/mL Andro could significantly induce Jurkat cells’ apoptosis, depending on the inhibition of PI3K/AKT pathway. Moreover, Andro-induced apoptosis is enhanced by AKT-selective inhibitor LY294002. ERK- or JNK-selective inhibitors PD98059 and SP600125 had no effect on Andro-induced apoptosis. In addition, p38 inhibitor SB203580 could reverse Andro-induced apoptosis in Jurkat cells. We also found that the protein expression of p-p53 and p-p38 were increased after Andro treatments. The result of an in vivo study also demonstrated Andro’s dose-dependent inhibition in subcutaneous Jurkat xenografts. In conclusion, our findings explained a novel mechanism of drug action by Andro in Jurkat cells and suggested that Andro might be developed into a new candidate therapy for T-ALL patients in the coming days. Keywords: andrographolide, PI3K, AKT, Burkitt lymphoma, Jurkat cell

  6. 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.

  7. Calycosin induces apoptosis in colorectal cancer cells, through modulating the ERβ/MiR-95 and IGF-1R, PI3K/Akt signaling pathways.

    Science.gov (United States)

    Zhao, Xinge; Li, Xin; Ren, Qianyao; Tian, Jing; Chen, Jian

    2016-10-10

    Calycosin, the main component extractable from the herb Radix astragali, has been shown to inhibit cellular proliferation and induce apoptosis in several cancer cell lines, but the underlying mechanisms by the way in which this occurs remain unclear. In the present study, we aimed to determine the potential effects of calycosin on proliferation in colorectal cancer cells in vitro and in vivo and to elucidate the underlying molecular mechanisms of action. Colorectal cancer cell lines SW480 and LoVo and cervical cancer cell line HeLa were treated with various concentrations of calycosin or plus ER beta (ERβ) inhibitor PHTPP. The CCK8 assay, flow cytometry, and Hoechst 33258 stain were used to assess the effects on cellular proliferation and apoptosis. The mRNA levels of ERβ and miR-95 were quantified by real-time PCR. The protein expression levels of ERβ, ERα, IGF-1R, and p-Akt were evaluated by Western blot analysis. We demonstrated that calycosin inhibited the proliferation in SW480 and LoVo cells and induced apoptosis, particularly in SW480 cells, but not in HeLa cells. Calycosin increased ERβ expression and reduced the ERα, IGF-1R, and p-Akt expression alongside down-regulation of miR-95 in SW480 cells. Inhibiting ERβ blocked the change of miR-95 and the resulting increase in apoptosis in SW480 cells. Additionally, calycosin significantly suppressed xenograft tumor growth in nude mice. In conclusion, calycosin exerts an inhibitory effect on proliferation of CRC cells in vivo and in vitro, through ERβ-mediated regulation of the IGF-1R, PI3K/Akt signaling pathways and of miR-95 expression. PMID:27393650

  8. Calycosin ameliorates diabetes-induced cognitive impairments in rats by reducing oxidative stress via the PI3K/Akt/GSK-3β signaling pathway.

    Science.gov (United States)

    Wang, Xiang; Zhao, Linhui

    2016-04-29

    Diabetic encephalopathy is one of the most prevalent chronic complications of diabetes mellitus (DM), but there is currently no effective method of prevention nor proven therapeutic regimen for it. In this study, we investigated the effects of calycosin on cognitive behavior and the potential mechanism involved in streptozocin-induced diabetic rats. The effects of diabetes and calycosin treatment on spatial learning and memory were evaluated using the Morris Water Maze, passive avoidance and motor coordination tests. Histological analysis of the hippocampus cornu ammonis 1 (CA1) region was conducted in rats. The decreased expression of the synapsin (SYN) and postsynatptic density protein (PSD-95), as well as brain-derived neurotrophic factor (BDNF) in diabetic rats was measured by quantitative real-time PCR and western blot. Treatment with calycosin promoted a reduction in the expression of SYN, PSD-95 and BDNF. In addition, diabetic rats showed increased MDA levels, and decreased SOD levels and GSH-Px activities in the hippocampus, as well as increased AChE activity in the cerebral cortex; these changes were reversed by calycosin supplementation. Thus, the impairment of learning and memory in STZ-induced diabetic rats was alleviated by calycosin, and that the degree of alleviation was associated with oxidative stress. We also found that calycosin treatment significantly stimulated Akt phosphorylation and decreased GSK-3β and tau phosphorylation, and that these changes could be restored by the PI3K/Akt inhibitor LY294002. In conclusion, calycosin had a beneficial effect on the amelioration, prevention and treatment of diabetes-associated cognitive deficits, through its involvement in oxidative stress, synaptic function and the PI3K/Akt/GSK-3β pathway. PMID:26970304

  9. Hypoxia activates Akt and induces phosphorylation of GSK-3 in PC12 cells.

    Science.gov (United States)

    Beitner-Johnson, D; Rust, R T; Hsieh, T C; Millhorn, D E

    2001-01-01

    Akt is a serine/threonine kinase that has been shown to play a central role in promoting cell survival and opposing apoptosis. We evaluated the effect of hypoxia on Akt in rat pheochromocytoma (PC12) cells. PC12 cells were exposed to varying levels of hypoxia, including 21%, 15%, 10%, 5%, and 1% O(2). Hypoxia dramatically increased phosphorylation of Akt (Ser(473)). This effect peaked after 6 h exposure to hypoxia, but persisted strongly for up to 24 h. Phosphorylation of Akt was paralleled with a progressive increase in phosphorylation of glycogen synthase kinase-3 (GSK-3), one of its downstream substrates. The effect of hypoxia on phosphorylation of Akt was completely blocked by pretreatment of the cells with wortmannin (100 nM), indicating that this effect is mediated by phosphatidylinositol 3-kinase (P13K). In contrast, whereas hypoxia also strongly induced phosphorylation of the transcription factors CREB and EPAS1, these effects persisted in the presence of wortmannin. Thus, hypoxia regulates both P13K-dependent and P13K-independent signaling pathways. Furthermore, activation of the P13K and Akt signaling pathways may be one mechanism by which cells adapt and survive under conditions of hypoxia. PMID:11257444

  10. Calycosin suppresses breast cancer cell growth via ERβ-dependent regulation of IGF-1R, p38 MAPK and PI3K/Akt pathways.

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    Jian Chen

    Full Text Available We previously reported that calycosin, a natural phytoestrogen structurally similar to estrogen, successfully triggered apoptosis of estrogen receptor (ER-positive breast cancer cell line, MCF-7. To better understand the antitumor activities of calycosin against breast cancer, besides MCF-7 cells, another ER-positive cell line T-47D was analyzed here, with ER-negative cell lines (MDA-231, MDA-435 as control. Notably, calycosin led to inhibited cell proliferation and apoptosis only in ER-positive cells, particularly in MCF-7 cells, whereas no such effect was observed in ER-negative cells. Then we investigated whether regulation of ERβ, a subtype of ER, contributed to calycosin-induced apoptosis in breast cancer cells. The results showed that incubation of calycosin resulted in enhanced expression ERβ in MCF-7 and T-47D cells, rather than MDA-231 and MDA-435 cells. Moreover, with the upregulation of ERβ, successive changes in downstream signaling pathways were found, including inactivation of insulin-like growth factor 1 receptor (IGF-1R, then stimulation of p38 MAPK and suppression of the serine/threonine kinase (Akt, and finally poly(ADP-ribose polymerase 1 (PARP-1 cleavage. However, the other two members of the mitogen-activated protein kinase (MAPK family, extracellular signal-regulated kinase (ERK 1/2 and c-Jun N-terminal kinase (JNK, were not consequently regulated by downregulated IGF-1R, indicating ERK 1/2 and JNK pathways were not necessary to allow proliferation inhibition by calycosin. Taken together, our results indicate that calycosin tends to inhibit growth and induce apoptosis in ER-positive breast cancer cells, which is mediated by ERβ-induced inhibition of IGF-1R, along with the selective regulation of MAPK and phosphatidylinositol 3-kinase (PI3K/Akt pathways.

  11. Cigarette sidestream smoke induces histone H3 phosphorylation via JNK and PI3K/Akt pathways, leading to the expression of proto-oncogenes.

    Science.gov (United States)

    Ibuki, Yuko; Toyooka, Tatsushi; Zhao, Xiaoxu; Yoshida, Ikuma

    2014-06-01

    Post-translational modifications in histones have been associated with cancer. Although cigarette sidestream smoke (CSS) as well as mainstream smoke are carcinogens, the relationship between carcinogenicity and histone modifications has not yet been clarified. Here, we demonstrated that CSS induced phosphorylation of histones, involving a carcinogenic process. Treatment with CSS markedly induced the phosphorylation of histone H3 at serine 10 and 28 residues (H3S10 and H3S28), which was independent from the cell cycle, in the human pulmonary epithelial cell model, A549 and normal human lung fibroblasts, MRC-5 and WI-38. Using specific inhibitors and small interfering RNA, the phosphorylation of H3S10 was found to be mediated by c-jun N-terminal kinase (JNK) and phosphoinositide 3-kinase (PI3K)/Akt pathways. These pathways were different from that of the CSS-induced phosphorylation of histone H2AX (γ-H2AX) mediated by Ataxia telangiectasia-mutated (ATM) and ATM-Rad3-related (ATR) protein kinases. A chromatin immunoprecipitation assay revealed that the phosphorylation of H3S10 was increased in the promoter sites of the proto-oncogenes, c-fos and c-jun, which indicated that CSS plays a role in tumor promotion. Because the phosphorylation of H3S10 was decreased in the aldehyde-removed CSS and was significantly induced by treatment with formaldehyde, aldehydes are suspected to partially contribute to this phosphorylation. These findings suggested that any chemicals in CSS, including aldehydes, phosphorylate H3S10 via JNK and PI3K/Akt pathways, which is different from the DNA damage response, resulting in tumor promotion.

  12. Citrus aurantium flavonoids inhibit adipogenesis through the Akt signaling pathway in 3T3-L1 cells

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    Kim Gon-Sup

    2012-04-01

    Full Text Available Abstract Background Obesity is a health hazard that is associated with a number of diseases and metabolic abnormalities, such as type-2 diabetes, hypertension, dyslipidemia, and coronary heart disease. In the current study, we investigated the effects of Citrus aurantium flavonoids (CAF on the inhibition of adipogenesis and adipocyte differentiation in 3T3-L1 cells. Methods During adipocyte differentiation, 3T3-L1 cells were treated with 0, 10, and 50 μg/ml CAF, and then the mRNA and protein expression of adipogenesis-related genes was assayed. We examined the effect of CAF on level of phosphorylated Akt in 3T3-L1 cells treated with CAF at various concentrations during adipocyte differentiation. Results The insulin-induced expression of C/EBPβ and PPARγ mRNA and protein were significantly down-regulated in a dose-dependent manner following CAF treatment. CAF also dramatically decreased the expression of C/EBPα, which is essential for the acquisition of insulin sensitivity by adipocytes. Moreover, the expression of the aP2 and FAS genes, which are involved in lipid metabolism, decreased dramatically upon treatment with CAF. Interestingly, CAF diminished the insulin-stimulated serine phosphorylation of Akt (Ser473 and GSK3β (Ser9, which may reduce glucose uptake in response to insulin and lipid accumulation. Furthermore, CAF not only inhibited triglyceride accumulation during adipogenesis but also contributed to the lipolysis of adipocytes. Conclusions In the present study, we demonstrate that CAF suppressed adipogenesis in 3T3-L1 adipocytes. Our results indicated that CAF down-regulates the expression of C/EBPβ and subsequently inhibits the activation of PPARγ and C/EBPα. The anti-adipogenic activity of CAF was mediated by the inhibition of Akt activation and GSK3β phosphorylation, which induced the down-regulation of lipid accumulation and lipid metabolizing genes, ultimately inhibiting adipocyte differentiation.

  13. Tyrosine kinase inhibitors influence ABCG2 expression in EGFR-positive MDCK BCRP cells via the PI3K/Akt signaling pathway.

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    Pick, Anne; Wiese, Michael

    2012-04-01

    Multidrug resistance observed in cancer chemotherapy is commonly attributed to overexpression of efflux transporter proteins. These proteins act as ATP-dependent drug efflux pumps, actively extruding chemotherapeutic agents from cells and causing a decrease in intracellular drug accumulation. Besides the well-recognized role of P-glycoprotein (P-gp, ABCB1), the breast cancer resistance protein (BCRP, ABCG2) is becoming increasingly accepted as playing an important role in multidrug resistance. In contrast to P-glycoprotein, only a few inhibitors of ABCG2 are known. According to the literature, tyrosine kinase inhibitors (TKIs) can be considered to be broad-spectrum inhibitors, interacting with ABCB1, ABCC1 and ABCG2. Here, we investigated seven different TKIs, gefitinib, erlotinib, AG1478, PD158780, PD153035, nilotinib and imatinib, for their potential to restore ABCG2 sensitivity to cells. Furthermore, we analyzed the alteration of ABCG2 expression caused by TKIs and demonstrated that EGFR inhibitors such as gefitinib and PD158780 reduced both total and surface expression of ABCG2 in EGRF-positive MDCK BCRP cells by interaction with the PI3K/Akt signaling pathway. The reduced ABCG2 content led to an increased effect of XR9577, a well-known ABCG2 modulator, lowering the concentration required for half maximal inhibition. On the other hand, BCR-ABL inhibitors had no influence on ABCG2 expression and modulator activity. Interestingly, a combination of an EGFR inhibitor with the PI3K/Akt inhibitor LY294002 led to a significant reduction of ABCG2 expression at low concentrations of the drugs. Based on our results, we assume that EGFR exerts a post-transcriptional enhancing effect on ABCG2 expression via the PI3K/Akt signaling pathway, which can be attenuated by EGFR inhibitors. Blocking the key signaling pathway regulating ABCG2 expression with EGFR inhibitors, combined with the inhibition of ABCG2 with potent modulators might be a promising approach to circumvent MDR

  14. α-Solanine induces ROS-mediated autophagy through activation of endoplasmic reticulum stress and inhibition of Akt/mTOR pathway.

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    Hasanain, M; Bhattacharjee, A; Pandey, P; Ashraf, R; Singh, N; Sharma, S; Vishwakarma, A L; Datta, D; Mitra, K; Sarkar, J

    2015-08-27

    α-Solanine is a glycoalkaloid found in species of the nightshade family including potato. It was primarily reported to have toxic effects in humans. However, there is a growing body of literature demonstrating in vitro and in vivo anticancer activity of α-solanine. Most of these studies have shown activation of apoptosis as the underlying mechanism in antitumor activity of α-solanine. In this study, we report α-solanine as a potential inducer of autophagy, which may act synergistically or in parallel with apoptosis to exert its cytotoxic effect. Induction of autophagy was demonstrated by several assays including electron microscopy, immunoblotting of autophagy markers and immunofluorescence for LC3 (microtubule-associated protein 1 (MAP1) light chain-3) puncta. α-Solanine-induced autophagic flux was demonstrated by additionally enhanced--turnover of LC3-II and--accumulation of LC3-specific puncta after co-incubation of cells with either of the autophagolysosome inhibitors--chloroquine and--bafilomycin A1. We also demonstrated α-solanine-induced oxidative damage in regulating autophagy where pre-incubation of cells with reactive oxygen species (ROS) scavenger resulted in suppression of CM-H2DCFDA (5 (and 6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate acetyl ester) fluorescence as well as decrease in LC3-II turnover. α-Solanine treatment caused an increase in the expression of endoplasmic reticulum (ER) stress proteins (BiP, activating transcription factor 6 (ATF6), X-box-binding protein 1, PERK, inositol-requiring transmembrane kinase/endonuclease 1, ATF4 and CCAAT-enhancer-binding protein (C/EBP)-homologous protein) suggesting activation of unfolded protein response pathway. Moreover, we found downregulation of phosphorylated Akt (Thr308 and Ser473), mammalian target of rapamycin (mTOR; Ser2448 and Ser2481) and 4E-BP1 (Thr37/46) by α-solanine implying suppression of the Akt/mTOR pathway. Collectively, our results signify that α-solanine induces

  15. Centrosomal Protein of 55 Regulates Glucose Metabolism, Proliferation and Apoptosis of Glioma Cells via the Akt/mTOR Signaling Pathway

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    Wang, Guangzhi; Liu, Mingna; Wang, Hongjun; Yu, Shan; Jiang, Zhenfeng; Sun, Jiahang; Han, Ke; Shen, Jia; Zhu, Minwei; Lin, Zhiguo; Jiang, Chuanlu; Guo, Mian

    2016-01-01

    Introduction: Glioma is one of the most common and most aggressive brain tumors in humans. The molecular and cellular mechanisms responsible for the onset and the progression of glioma are elusive and controversial. Centrosomal protein of 55 (CEP55) was initially described as a highly coiled-coil protein that plays critical roles in cell division, but was recently identified as being overexpressed in many human cancers. The function of CEP55 has not previously been characterized in glioma. We aim to discover the effect and mechanism of CEP55 in glioma development. Method: qRT-PCR and immunohistochemistry were used to analyze CEP55 expression. Glucose uptake, western blot, MTS, CCK-8, Caspase-3 activity and TUNEL staining assays were performed to investigate the role and mechanism of CEP55 on glioma cell process. Results: We found that the levels of CEP55 expression were upregulated in glioma. In addition, CEP55 appeared to regulate glucose metabolism of glioma cells. Furthermore, knockdown of CEP55 inhibited cell proliferation and induced cell apoptosis in glioma. Finally, we provided preliminary evidence that knockdown of CEP55 inhibited glioma development via suppressing the activity of Akt/mTOR signaling. Conclusions: Our results demonstrated that CEP55 regulates glucose metabolism, proliferation and apoptosis of glioma cells via the Akt/mTOR signaling pathway, and its promotive effect on glioma tumorigenesis can be a potential target for glioma therapy in the future. PMID:27471559

  16. The Marine Metabolite SZ-685C Induces Apoptosis in Primary Human Nonfunctioning Pituitary Adenoma Cells by Inhibition of the Akt Pathway in Vitro

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    Xin Wang

    2015-03-01

    Full Text Available Nonfunctioning pituitary adenoma (NFPA is one of the most common types of pituitary adenoma. The marine anthraquinone derivative SZ-685C has been isolated from the secondary metabolites of the mangrove endophytic fungus Halorosellinia sp. (No. 1403 which is found in the South China Sea. Recent research has shown that SZ-685C possesses anticancer and tumor suppressive effects. The tetrazolium-based colorimetric assay (MTT assay to investigate the different effect of the marine compound SZ-685C on the proliferation of primary human NFPA cells, rat normal pituitary cells (RPCs and rat prolactinoma MMQ cell lines. Hoechst 33342 dye/propidium iodide (PI double staining and fluorescein isothiocyanate-conjugated Annexin V/PI (Annexin V-FITC/PI apoptosis assays detected an enhanced rate of apoptosis in cells treated with SZ-685C. Enhanced expression levels of caspase 3 and phosphate and tensin homolog (PTEN were determined by Western blotting. Notably, the protein expression levels of Akt were decreased when the primary human NFPA cells were treated with SZ-685C. Here, we show that SZ-685C induces apoptosis of human NFPA cells through inhibition of the Akt pathway in vitro. The understanding of apoptosis has provided the basis for novel targeted therapies that can induce death in cancer cells or sensitize them to established cytotoxic agents and radiation therapy.

  17. Hypoglycemic effect of D-chiro-inositol in type 2 diabetes mellitus rats through the PI3K/Akt signaling pathway.

    Science.gov (United States)

    Gao, Yun-Feng; Zhang, Meng-Na; Wang, Tian-Xin; Wu, Tian-Chen; Ai, Ru-Dan; Zhang, Ze-Sheng

    2016-09-15

    In this investigation, a model of type 2 diabetes mellitus (T2DM) was used on Sprague-Dawley (SD) rats to clarify more details of the mechanism in the therapy of T2DM. D-chiro-inositol (DCI) was administrated to the diabetic rats as two doses [30, 60 mg/(kg·body weight·day)]. The biochemical indices revealed that DCI had a positive effect on hypoglycemic activity and promoted the glycogen synthesis. The rats in DCI high-dosage group had a blood glucose reduction rate of 21.5% after 5 weeks of treatment, and had insulin content in serum about 15.3 ± 2.37 mIU/L which was significantly decreased than diabetes control group. Real-time polymerase chain reaction (RT-PCR) results revealed that DCI gave a positive regulation on glycogen synthase (GS) and protein glucose transporter-4 (Glut4). Western blotting suggested that DCI could up-regulated the expression of the phosphatidylinositol-3-kinase (PI3K) p85, PI3Kp110, GS as well as the phosphorylation of protein kinase B (Akt) both in the liver and the skeletal muscle. The results also revealed that DCI enhanced the Glut4 expression on skeletal muscle. Above all, DCI played a positive role in regulating insulin-mediated glucose uptake through the PI3K/Akt signaling pathway in T2DM rats. PMID:27212205

  18. Lycopene inhibits PDGF-BB-induced retinal pigment epithelial cell migration by suppression of PI3K/Akt and MAPK pathways

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    Chan, Chi-Ming [School of Medicine, Fu Jen Catholic University, Taipei Hsien, Taiwan, ROC (China); Department of Ophthalmology, Cardinal Tien Hospital, Taipei Hsien, Taiwan, ROC (China); Fang, Jia-You [Pharmaceutics Laboratory, Graduate Institute of Natural Products, Chang Gung University, Kweishan, Taoyuan, Taiwan, ROC (China); Lin, Hsin-Huang [School of Medicine, Fu Jen Catholic University, Taipei Hsien, Taiwan, ROC (China); Yang, Chi-Yea [Department of Biotechnology, Vanung University, Taoyuan, Taiwan, ROC (China); Hung, Chi-Feng, E-mail: 054317@mail.fju.edu.tw [School of Medicine, Fu Jen Catholic University, Taipei Hsien, Taiwan, ROC (China)

    2009-10-09

    Retinal pigment epithelial (RPE) cells play a dominant role in the development of proliferative vitreoretinopathy (PVR), which is the leading cause of failure in retinal reattachment surgery. Several studies have shown that platelet-derived growth factor (PDGF) exhibits chemotaxis and proliferation effects on RPE cells in PVR. In this study, the inhibitory effect of lycopene on PDGF-BB-induced ARPE19 cell migration is examined. In electric cell-substrate impedance sensing (ECIS) and Transwell migration assays, significant suppression of PDGF-BB-induced ARPE19 cell migration by lycopene is observed. Cell viability assays show no cytotoxicity of lycopene on RPE cells. Lycopene shows no effect on ARPE19 cell adhesion and is found to inhibit PDGF-BB-induced tyrosine phosphorylation and the underlying signaling pathways of PI3K, Akt, ERK and p38 activation. However, PDGF-BB and lycopene show no effects on JNK activation. Taken together, our results demonstrate that lycopene inhibits PDGF-BB-induced ARPE19 cell migration through inhibition of PI3K/Akt, ERK and p38 activation.

  19. The marine metabolite SZ-685C induces apoptosis in primary human nonfunctioning pituitary adenoma cells by inhibition of the Akt pathway in vitro.

    Science.gov (United States)

    Wang, Xin; Tan, Ting; Mao, Zhi-Gang; Lei, Ni; Wang, Zong-Ming; Hu, Bin; Chen, Zhi-Yong; She, Zhi-Gang; Zhu, Yong-Hong; Wang, Hai-Jun

    2015-03-01

    Nonfunctioning pituitary adenoma (NFPA) is one of the most common types of pituitary adenoma. The marine anthraquinone derivative SZ-685C has been isolated from the secondary metabolites of the mangrove endophytic fungus Halorosellinia sp. (No. 1403) which is found in the South China Sea. Recent research has shown that SZ-685C possesses anticancer and tumor suppressive effects. The tetrazolium-based colorimetric assay (MTT assay) to investigate the different effect of the marine compound SZ-685C on the proliferation of primary human NFPA cells, rat normal pituitary cells (RPCs) and rat prolactinoma MMQ cell lines. Hoechst 33342 dye/propidium iodide (PI) double staining and fluorescein isothiocyanate-conjugated Annexin V/PI (Annexin V-FITC/PI) apoptosis assays detected an enhanced rate of apoptosis in cells treated with SZ-685C. Enhanced expression levels of caspase 3 and phosphate and tensin homolog (PTEN) were determined by Western blotting. Notably, the protein expression levels of Akt were decreased when the primary human NFPA cells were treated with SZ-685C. Here, we show that SZ-685C induces apoptosis of human NFPA cells through inhibition of the Akt pathway in vitro. The understanding of apoptosis has provided the basis for novel targeted therapies that can induce death in cancer cells or sensitize them to established cytotoxic agents and radiation therapy. PMID:25806467

  20. 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.

  1. Small ribosomal protein subunit S7 suppresses ovarian tumorigenesis through regulation of the PI3K/AKT and MAPK pathways.

    Science.gov (United States)

    Wang, Ziliang; Hou, Jing; Lu, Lili; Qi, Zihao; Sun, Jianmin; Gao, Wen; Meng, Jiao; Wang, Yan; Sun, Huizhen; Gu, Hongyu; Xin, Yuhu; Guo, Xiaomao; Yang, Gong

    2013-01-01

    Small ribosomal protein subunit S7 (RPS7) has been reported to be associated with various malignancies, but the role of RPS7 in ovarian cancer remains unclear. In this study, we found that silencing of RPS7 by a specific shRNA promoted ovarian cancer cell proliferation, accelerated cell cycle progression, and slightly reduced cell apoptosis and response to cisplatin treatment. Knockdown of RPS7 resulted in increased expression of P85α, P110α, and AKT2. Although the basal levels of ERK1/2, MEK1/2, and P38 were inconsistently altered in ovarian cancer cells, the phosphorylated forms of MEK1/2 (Ser217/221), ERK1/2 (Thr202/Tyr204), JNK1/2 (Thr183/Tyr185), and P38 (Thr180/Tyr182) were consistently reduced after RPS7 was silenced. Both the in vitro anchorage-independent colony formation and in vivo animal tumor formation capability of cells were enhanced after RPS7 was depleted. We also showed that silencing of RPS7 enhanced ovarian cancer cell migration and invasion. In sum, our results suggest that RPS7 suppresses ovarian tumorigenesis and metastasis through PI3K/AKT and MAPK signal pathways. Thus, RPS7 may be used as a potential marker for diagnosis and treatment of ovarian cancer.

  2. Small ribosomal protein subunit S7 suppresses ovarian tumorigenesis through regulation of the PI3K/AKT and MAPK pathways.

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    Ziliang Wang

    Full Text Available Small ribosomal protein subunit S7 (RPS7 has been reported to be associated with various malignancies, but the role of RPS7 in ovarian cancer remains unclear. In this study, we found that silencing of RPS7 by a specific shRNA promoted ovarian cancer cell proliferation, accelerated cell cycle progression, and slightly reduced cell apoptosis and response to cisplatin treatment. Knockdown of RPS7 resulted in increased expression of P85α, P110α, and AKT2. Although the basal levels of ERK1/2, MEK1/2, and P38 were inconsistently altered in ovarian cancer cells, the phosphorylated forms of MEK1/2 (Ser217/221, ERK1/2 (Thr202/Tyr204, JNK1/2 (Thr183/Tyr185, and P38 (Thr180/Tyr182 were consistently reduced after RPS7 was silenced. Both the in vitro anchorage-independent colony formation and in vivo animal tumor formation capability of cells were enhanced after RPS7 was depleted. We also showed that silencing of RPS7 enhanced ovarian cancer cell migration and invasion. In sum, our results suggest that RPS7 suppresses ovarian tumorigenesis and metastasis through PI3K/AKT and MAPK signal pathways. Thus, RPS7 may be used as a potential marker for diagnosis and treatment of ovarian cancer.

  3. The silencing of Pokemon attenuates the proliferation of hepatocellular carcinoma cells in vitro and in vivo by inhibiting the PI3K/Akt pathway.

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    Chan-Chan Lin

    Full Text Available Pokemon (POK erythroid myeloid ontogenic factor, which belongs to the POK protein family, is also called LRF, OCZF and FBI-1. As a transcriptional repressor, Pokemon assumes a critical function in cellular differentiation and oncogenesis. Our study identified an oncogenic role for Pokemon in human hepatocellular carcinoma (HCC. We successfully established human HepG2 and Huh-7 cell lines in which Pokemon was stably knocked down. We demonstrated that Pokemon silencing inhibited cell proliferation and migration. Pokemon knockdown inhibited the PI3K/Akt and c-Raf/MEK/ERK pathways and modulated the expression of various cell cycle regulators in HepG2 and Huh-7 cells. Therefore, Pokemon may also be involved in cell cycle progression in these cells. We confirmed that Pokemon silencing suppresses hepatocellular carcinoma growth in tumor xenograft mice. These results suggest that Pokemon promotes cell proliferation and migration in hepatocellular carcinoma and accelerates tumor development in an Akt- and ERK-signaling-dependent manner.

  4. Andrographolide inhibits growth of human T-cell acute lymphoblastic leukemia Jurkat cells by downregulation of PI3K/AKT and upregulation of p38 MAPK pathways.

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    Yang, Tingfang; Yao, Shuluan; Zhang, Xianfeng; Guo, Yan

    2016-01-01

    T-cell acute lymphoblastic leukemia (T-ALL) as a prevalent hematologic malignancy is one of the most common malignant tumors worldwide in children. Andrographolide (Andro), the major active component from Andrographis paniculata, has been shown to possess antitumor activities in several types of cancer cells. However, whether Andro would inhibit T-ALL cell growth remains unclear. In this study, we investigated the cytotoxic effect of Andro on human T-ALL Jurkat cells and explored the mechanisms of cell death. Cell apoptosis was assayed by flow cytometry, and the signaling transduction for Andro was analyzed by Western blotting. The results indicated 10 μg/mL Andro could significantly induce Jurkat cells' apoptosis, depending on the inhibition of PI3K/AKT pathway. Moreover, Andro-induced apoptosis is enhanced by AKT-selective inhibitor LY294002. ERK- or JNK-selective inhibitors PD98059 and SP600125 had no effect on Andro-induced apoptosis. In addition, p38 inhibitor SB203580 could reverse Andro-induced apoptosis in Jurkat cells. We also found that the protein expression of p-p53 and p-p38 were increased after Andro treatments. The result of an in vivo study also demonstrated Andro's dose-dependent inhibition in subcutaneous Jurkat xenografts. In conclusion, our findings explained a novel mechanism of drug action by Andro in Jurkat cells and suggested that Andro might be developed into a new candidate therapy for T-ALL patients in the coming days. PMID:27114702

  5. H2 S inhibits apo(a) expression and secretion through PKCα/FXR and Akt/HNF4α pathways in HepG2 cells.

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    Qu, Kai; Liu, Ya-Mi; He, Xing-Lan; Zhang, Hai; Zhang, Kai; Peng, Juan; Tang, Ya-Ling; Yu, Xiao-Hua; Zeng, Jun-Fa; Lei, Jian-Jun; Wei, Dang-Heng; Wang, Zuo

    2016-08-01

    Lipoprotein(a) [Lp(a)] is a strong genetic risk factor for coronary heart diseases. However, the metabolism of this protein remains poorly understood. Efficient and specific drugs that can decrease high plasma levels of Lp(a) have not been developed yet. Hydrogen sulfide (H2 S), a member of the gas transmitter family, performs important biological actions, including protection against cardiovascular diseases and maintenance of the lipid metabolism equilibrium in hepatocytes and adipocytes. In this study, we investigated the possible molecular mechanism of H2 S that influences apolipoprotein(a) [apo(a)] biosynthesis. We also determined the effects of H2 S on apo(a) expression and secretion in HepG2 cells as well as the underlying mechanisms. Results showed that H2 S significantly inhibited the expression and secretion levels of apo(a). These effects were attenuated by the PKCα inhibitor and FXR siRNA. H2 S also reduced HNF4α expression and enhanced FXR expression. The Akt inhibitor partially reversed H2 S-induced inhibition of apo(a) and HNF4α expression and apo(a) secretion. This study reveals that H2 S suppressed apo(a) expression and secretion via the PKCα-FXR and PI3K/Akt-HNF4α pathways. PMID:27298021

  6. The silencing of Pokemon attenuates the proliferation of hepatocellular carcinoma cells in vitro and in vivo by inhibiting the PI3K/Akt pathway.

    Science.gov (United States)

    Lin, Chan-Chan; Zhou, Jing-Ping; Liu, Yun-Peng; Liu, Jing-Jing; Yang, Xiao-Ning; Jazag, Amarsanaa; Zhang, Zhi-Ping; Guleng, Bayasi; Ren, Jian-Lin

    2012-01-01

    Pokemon (POK erythroid myeloid ontogenic factor), which belongs to the POK protein family, is also called LRF, OCZF and FBI-1. As a transcriptional repressor, Pokemon assumes a critical function in cellular differentiation and oncogenesis. Our study identified an oncogenic role for Pokemon in human hepatocellular carcinoma (HCC). We successfully established human HepG2 and Huh-7 cell lines in which Pokemon was stably knocked down. We demonstrated that Pokemon silencing inhibited cell proliferation and migration. Pokemon knockdown inhibited the PI3K/Akt and c-Raf/MEK/ERK pathways and modulated the expression of various cell cycle regulators in HepG2 and Huh-7 cells. Therefore, Pokemon may also be involved in cell cycle progression in these cells. We confirmed that Pokemon silencing suppresses hepatocellular carcinoma growth in tumor xenograft mice. These results suggest that Pokemon promotes cell proliferation and migration in hepatocellular carcinoma and accelerates tumor development in an Akt- and ERK-signaling-dependent manner. PMID:23300578

  7. Annexin A2 Regulates Autophagy in Pseudomonas aeruginosa Infection through the Akt1-mTOR-ULK1/2 Signaling Pathway.

    Science.gov (United States)

    Li, Rongpeng; Tan, Shirui; Yu, Min; Jundt, Michael C; Zhang, Shuang; Wu, Min

    2015-10-15

    Earlier studies reported that a cell membrane protein, Annexin A2 (AnxA2), plays multiple roles in the development, invasion, and metastasis of cancer. Recent studies demonstrated that AnxA2 also functions in immunity against infection, but the underlying mechanism remains largely elusive. Using a mouse infection model, we reveal a crucial role for AnxA2 in host defense against Pseudomonas aeruginosa, as anxa2(-/-) mice manifested severe lung injury, systemic dissemination, and increased mortality compared with wild-type littermates. In addition, anxa2(-/-) mice exhibited elevated inflammatory cytokines (TNF-α, IL-6, IL-1β, and IFN-γ), decreased bacterial clearance by macrophages, and increased superoxide release in the lung. We further identified an unexpected molecular interaction between AnxA2 and Fam13A, which activated Rho GTPase. P. aeruginosa infection induced autophagosome formation by inhibiting Akt1 and mTOR. Our results indicate that AnxA2 regulates autophagy, thereby contributing to host immunity against bacteria through the Akt1-mTOR-ULK1/2 signaling pathway.

  8. Oridonin inhibits gefitinib-resistant lung cancer cells by suppressing EGFR/ERK/MMP-12 and CIP2A/Akt signaling pathways.

    Science.gov (United States)

    Xiao, Xiangling; He, Zhongwei; Cao, Wei; Cai, Fen; Zhang, Liang; Huang, Qiuyue; Fan, Chunsheng; Duan, Chao; Wang, Xiaobo; Wang, Jiu; Liu, Ying

    2016-06-01

    Oridonin (Ori), a diterpenoid compound extracted from traditional medicinal herbs, elicits antitumor effects on many cancer types. However, whether Ori can be used in gefitinib-resistant non-small cell lung cancer (NSCLC) cells remains unclear. This study investigated the antitumor activity and underlying mechanisms of Ori. Results demonstrated that this compound dose-dependently inhibited the proliferation, invasion, and migration of the gefitinib-resistant NSCLC cells in vitro. Ori also significantly downregulated the phosphorylation of EGFR, ERK, Akt, expression levels of matrix metalloproteinase-12 (MMP-12), and the cancerous inhibitor of protein phosphatase 2A (CIP2A). In addition, Ori upregulated protein phosphatase 2A (PP2A) activity of gefitinib-resistant NSCLC cells. Ori combined with docetaxel synergistically inhibited these cells. Ori also inhibited tumor growth in murine models. Immunohistochemistry results further revealed that Ori downregulated phospho-EGFR, MMP-12, and CIP2A in vivo. These findings indicated that Ori can inhibit the proliferation, invasion, and migration of gefitinib-resistant NSCLC cells by suppressing EGFR/ERK/MMP-12 and CIP2A/PP2A/Akt signaling pathways. Thus, Ori may be a novel effective candidate to treat gefitinib-resistant NSCLC.

  9. Asperosaponin VI promotes bone marrow stromal cell osteogenic differentiation through the PI3K/AKT signaling pathway in an osteoporosis model

    Science.gov (United States)

    Ke, Ke; Li, Qi; Yang, Xiaofeng; Xie, Zhijian; Wang, Yu; Shi, Jue; Chi, Linfeng; Xu, Weijian; Hu, Lingling; Shi, Huali

    2016-01-01

    Asperosaponin VI (ASA VI), a natural compound isolated from the well-known traditional Chinese herb Radix Dipsaci, has an important role in promoting osteoblast formation. However, its effects on osteoblasts in the context of osteoporosis is unknown. This study aimed to investigate the effects and mechanism of ASA VI action on the proliferation and osteogenic differentiation of bone marrow stromal cells isolated from the ovariectomized rats (OVX rBMSCs). The toxicity of ASA VI and its effects on the proliferation of OVX rBMSCs were measured using a CCK-8 assay. Various osteogenic differentiation markers were also analyzed, such as ALP activity, calcified nodule formation, and the expression of osteogenic genes, i.e., ALP, OCN, COL 1 and RUNX2. The results indicated that ASA VI promoted the proliferation of OVX rBMSCs and enhanced ALP activity and calcified nodule formation. In addition, while ASA VI enhanced the expression of ALP, OCN, Col 1 and RUNX2, treatment with LY294002 reduced all of these osteogenic effects and reduced the p-AKT levels induced by ASA VI. These results suggest that ASA VI promotes the osteogenic differentiation of OVX rBMSCs by acting on the phosphatidylinositol—3 kinase/AKT signaling pathway. PMID:27756897

  10. OPN induces FoxM1 expression and localization through ERK 1/2, AKT, and p38 signaling pathway in HEC-1A cells.

    Science.gov (United States)

    Xie, Yunpeng; Li, Yinghua; Kong, Ying

    2014-12-16

    Mammalian embryo implantation is an extremely complex process and requires endometrial receptivity. In order to establish this receptivity, sequential proliferation and differentiation during the menstrual cycle is necessary. Forkhead box M1 (FoxM1) is described as a major oncogenic transcription factor in tumor initiation, promotion and progression. According to these functions, we believe that FoxM1 should also play an essential role in embryo implantation. Osteopontin (OPN), an adhesion molecule, has been studied extensively in reproduction. In this study, we observed the expression and distribution of FoxM1 during the proliferative-phase and secretory-phase human endometrium and the pre-implantation mouse uterus firstly. Then we observed the relationship between OPN and FoxM1. Our results showed that FoxM1 was mainly distributed in glandular epithelium. OPN increased the expression of FoxM1 in the human uterine epithelial cell line HEC-1A cells in a time- and concentration-dependent manner. OPN regulates FoxM1 to influence HEC-1A cell proliferation through extracellular regulated protein kinases (ERK 1/2), protein kinase B (PKB, AKT), and the p38 mitogen activated protein kinases (p38MAPK, p38) signaling pathway. Inhibition of ERK 1/2, AKT and p38 suppressed OPN-induced FoxM1 expression and location. Our data indicate that FoxM1 might be regulated by OPN to influence endometrial proliferation to establish endometrial receptivity.

  11. 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.

  12. Sanguinarine Induces Apoptosis of Human Oral Squamous Cell Carcinoma KB Cells via Inactivation of the PI3K/Akt Signaling Pathway.

    Science.gov (United States)

    Lee, Tae Kyung; Park, Cheol; Jeong, Soon-Jeong; Jeong, Moon-Jin; Kim, Gi-Young; Kim, Wun-Jae; Choi, Yung Hyun

    2016-08-01

    Preclinical Research Sanguinarine, an alkaloid isolated from the root of Sanguinaria canadensis and other plants of the Papaveraceae family, selectively induces apoptotic cell death in a variety of human cancer cells, but its mechanism of action requires further elaboration. The present study investigated the pro-apoptotic effects of sanguinarine in human oral squamous cell carcinoma KB cells. Sanguinarine treatment increased DR5/TRAILR2 (death receptor 5/TRAIL receptor 2) expression and enhanced the activation of caspase-8 and cleavage of its substrate, Bid. Sanguinarine also induced the mitochondrial translocation of pro-apoptotic Bax, mitochondrial dysfunction, cytochrome c release to the cytosol, and activation of caspase-9 and -3. However, a pan-ca