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Sample records for pten lipid phosphatase

  1. PTEN inhibits BMI1 function independently of its phosphatase activity

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    Kapoor Anil

    2009-11-01

    Full Text Available Abstract Background PTEN is the second most mutated tumor suppressor gene other than p53. It suppresses tumorigenesis by dephosphorylating phosphatidylinositol (3,4,5-triphosphate (PIP3 to phosphatidylinositol (4,5-biphosphate (PIP2, thereby directly inhibiting phosphatidylinositol 3 kinase (PI3K-mediated tumorigenic activities. Consistent with this model of action, cytosolic PTEN is recruited to the plasma membrane to dephosphorylate PIP3. While nuclear PTEN has been shown to suppress tumorigenesis by governing genome integrity, additional mechanisms may also contribute to nuclear PTEN-mediated tumor suppression. The nuclear protein BMI1 promotes stem cell self-renewal and tumorigenesis and PTEN inhibits these events, suggesting that PTEN may suppress BMI1 function. Results We investigated whether PTEN inhibits BMI1 function during prostate tumorigenesis. PTEN binds to BMI1 exclusively in the nucleus. This interaction does not require PTEN's phosphatase activity, as phosphatase-deficient PTEN mutants, PTEN/C124S (CS, PTEN/G129E (GE, and a C-terminal PTEN fragment (C-PTEN excluding the catalytic domain, all associate with BMI1. Furthermore, the residues 186-286 of C-PTEN are sufficient for binding to BMI1. This interaction reduces BMI1's function. BMI1 enhances hTERT activity and reduces p16INK4A and p14ARF expression. These effects were attenuated by PTEN, PTEN(CS, PTEN(GE, and C-PTEN. Furthermore, knockdown of PTEN in DU145 cells increased hTERT promoter activity, which was reversed when BMI1 was concomitantly knocked-down, indicating that PTEN reduces hTERT promoter activity via inhibiting BMI1 function. Conversely, BMI1 reduces PTEN's ability to inhibit AKT activation, which can be attributed to its interaction with PTEN in the nucleus, making PTEN unavailable to dephosphorylate membrane-bound PIP3. Furthermore, BMI1 appears to co-localize with PTEN more frequently in clinical prostate tissue samples from patients diagnosed with PIN

  2. PTEN蛋白磷酸酶活性的作用%The Function of PTEN's Protein Phosphatase Activity

    Institute of Scientific and Technical Information of China (English)

    郝礼森; 刘小娟; 张晓岚

    2012-01-01

    PTEN一个具有磷酸酶活性的肿瘤抑制基因,是编码具有脂质磷酸酶活性和蛋白磷酸酶活性的双重特异性磷酸酶,其缺失或功能异常与人类恶性肿瘤的发生发展密切相关.PTEN的脂质磷酸酶活性和蛋白磷酸酶活性在调控肿瘤细胞的生物学行为、维持细胞正常的生理活动中均发挥了重要作用.但二者的作用重点及机制仍有不同,其蛋白磷酸酶活性主要侧重于调控细胞的黏附迁移及侵袭.为更好地认识PTEN蛋白磷酸酶活性的作用,该文对PTEN蛋白磷酸酶活性的作用及其机制作一简要综述.%Phosphatase and tensin homolog deleted on chromosome ten (PTEN), a tumor suppressorgene found to exhibit a dual specificity protein and lipid phosphatase activity, occurs deletion or dysfunction in a wide range of advanced cancers. Both lipid phosphatase activity and protein phosphatase activity of PTEN play an important role in regulating the biological behavior of tumor cell and maintaining normal cellular physiologic function. However, there are differences between lipid phosphatase activity and protein phosphatase activity in the focal point and mechanism of the function. And the function of its protein phosphatase activity is mainly to regulate the adhesion, migration and invasion of cell. In this article, the funcion of PTEN's protein phosphatase activity and its mechanisms were briefly summarized for a better understanding of its role.

  3. Role of phosphatase PTEN in the activation of extracellular signal-regulated kinases induced by estradiol in endometrial carcinoma cells

    Institute of Scientific and Technical Information of China (English)

    张育军; 魏丽惠; 王建六; 孙铁铮

    2003-01-01

    Objectives To study extracellular signal-regulated kinase (ERK) activation in the endometrial carcinoma cell line Ishikawa with stimulation by 17-β-estradiol, and to elucidate the role of phosphatase and tensin homologue (PTEN) and estrogen receptor (ER) subtype on the activation of ERKs.Methods Western blot was used to examine the expression of PTEN and PTEN (G129E) in Ishikawa cells after stable transfection as well as ERK activation in Ishikawa-EGFP, Ishikawa- PTEN and Ishikawa- PTEN (G129E) stimulated with various doses of 17-β-estradiol for different lengths of time. Western blot was also used for examining the expression of ERα and ERβ in NIH3T3 fibroblasts after transient transfection of pCXN2hERα and pCXN2hERβ. Then, ERK activation was examined after stimulation with 17-β-estradiol. Results 17-β-estradiol activated ERK cascades (mainly ERK2) in Ishikawa cells. The activation of ERK increased gradually as concentration of 17-β-estradiol also increased. The maximal activation of ERK2 took place 5 min after stimulation with 17-β-estradiol. The activation of ERK2 was inhibited markedly by PTEN, but not by PTEN (G129E). 17-β-estradiol activated ERK cascades in NIH3T3 fibroblasts after transient transfection of pCXN2hERα.Conclusions 17-β-estradiol activate ERK cascades in Ishikawa cells by integrating with ERα. Lipid phosphatase PTEN has an inhibitory role on the activation of ERK stimulated by 17-β-estradiol in Ishikawa cells.

  4. Focus on PTEN regulation

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    Miriam eBermudez-Brito

    2015-07-01

    Full Text Available The role of PTEN as a tumour suppressor has been for a long time attributed to its lipid phosphatase activity against PI(3,4,5P3, the phospholipid product of the class I PI3Ks. Besides its traditional role as a lipid phosphatase at the plasma membrane, a wealth of data has shown that PTEN can function independently of its phosphatase activity and that PTEN also exists and plays a role in the nucleus, in cytoplasmic organelles and extracellularly. Accumulating evidence has shed light on diverse physiological functions of PTEN which are accompanied by a complex regulation of its expression and activity. PTEN levels and function are regulated transcriptionally, post-transcriptionally and post-translationally. PTEN is also sensitive to regulation by its interacting proteins and its localization. Herein, we summarize the current knowledge on mechanisms that regulate the expression and enzymatic activity of PTEN and its role in human diseases.

  5. Effect of aging and dietary salt and potassium intake on endothelial PTEN (Phosphatase and tensin homolog on chromosome 10 function.

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    Wei-Zhong Ying

    Full Text Available Aging promotes endothelial dysfunction, defined as a reduction in bioavailable nitric oxide (NO produced by the endothelial isoform of nitric oxide synthase (NOS3. This enzyme is critically regulated by phosphorylation by protein kinase B (Akt, which in turn is regulated by the lipid phosphatase, PTEN. The present series of studies demonstrated a reduction in bioavailable NO as the age of rats increased from 1 to 12 months. At 12 months of age, rats no longer demonstrated increases in phosphorylated NOS3 in response to high dietary salt intake. Endothelial cell levels of PTEN increased with age and became refractory to change with increased salt intake. In contrast to the reduction in NO production, endothelial cell production of transforming growth factor-ß (TGF-ß relative to NO increased progressively with age. In macrovascular endothelial cells, PTEN was regulated in a dose-dependent fashion by TGF-ß, which was further regulated by extracellular [KCl]. When combined with prior studies, the present series of experiments suggested an integral role for PTEN in endothelial cell pathobiology of aging and an important mitigating function of TGF-ß in endothelial PTEN regulation. The findings further supported a role for diet in affecting vascular function through the production of TGF-ß and NO.

  6. PTEN phosphatase-independent maintenance of glandular morphology in a predictive colorectal cancer model system.

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    Jagan, Ishaan C; Deevi, Ravi K; Fatehullah, Aliya; Topley, Rebecca; Eves, Joshua; Stevenson, Michael; Loughrey, Maurice; Arthur, Kenneth; Campbell, Frederick Charles

    2013-11-01

    Organotypic models may provide mechanistic insight into colorectal cancer (CRC) morphology. Three-dimensional (3D) colorectal gland formation is regulated by phosphatase and tensin homologue deleted on chromosome 10 (PTEN) coupling of cell division cycle 42 (cdc42) to atypical protein kinase C (aPKC). This study investigated PTEN phosphatase-dependent and phosphatase-independent morphogenic functions in 3D models and assessed translational relevance in human studies. Isogenic PTEN-expressing or PTEN-deficient 3D colorectal cultures were used. In translational studies, apical aPKC activity readout was assessed against apical membrane (AM) orientation and gland morphology in 3D models and human CRC. We found that catalytically active or inactive PTEN constructs containing an intact C2 domain enhanced cdc42 activity, whereas mutants of the C2 domain calcium binding region 3 membrane-binding loop (M-CBR3) were ineffective. The isolated PTEN C2 domain (C2) accumulated in membrane fractions, but C2 M-CBR3 remained in cytosol. Transfection of C2 but not C2 M-CBR3 rescued defective AM orientation and 3D morphogenesis of PTEN-deficient Caco-2 cultures. The signal intensity of apical phospho-aPKC correlated with that of Na(+)/H(+) exchanger regulatory factor-1 (NHERF-1) in the 3D model. Apical NHERF-1 intensity thus provided readout of apical aPKC activity and associated with glandular morphology in the model system and human colon. Low apical NHERF-1 intensity in CRC associated with disruption of glandular architecture, high cancer grade, and metastatic dissemination. We conclude that the membrane-binding function of the catalytically inert PTEN C2 domain influences cdc42/aPKC-dependent AM dynamics and gland formation in a highly relevant 3D CRC morphogenesis model system.

  7. PTEN Phosphatase-Independent Maintenance of Glandular Morphology in a Predictive Colorectal Cancer Model System

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    Ishaan C. Jagan

    2013-11-01

    Full Text Available Organotypic models may provide mechanistic insight into colorectal cancer (CRC morphology. Three-dimensional (3D colorectal gland formation is regulated by phosphatase and tensin homologue deleted on chromosome 10 (PTEN coupling of cell division cycle 42 (cdc42 to atypical protein kinase C (aPKC. This study investigated PTEN phosphatase-dependent and phosphatase-independent morphogenic functions in 3D models and assessed translational relevance in human studies. Isogenic PTEN-expressing or PTEN-deficient 3D colorectal cultures were used. In translational studies, apical aPKC activity readout was assessed against apical membrane (AM orientation and gland morphology in 3D models and human CRC. We found that catalytically active or inactive PTEN constructs containing an intact C2 domain enhanced cdc42 activity, whereas mutants of the C2 domain calcium binding region 3 membrane-binding loop (M-CBR3 were ineffective. The isolated PTEN C2 domain (C2 accumulated in membrane fractions, but C2 M-CBR3 remained in cytosol. Transfection of C2 but not C2 M-CBR3 rescued defective AM orientation and 3D morphogenesis of PTEN-deficient Caco-2 cultures. The signal intensity of apical phospho-aPKC correlated with that of Na+/H+ exchanger regulatory factor-1 (NHERF-1 in the 3D model. Apical NHERF-1 intensity thus provided readout of apical aPKC activity and associated with glandular morphology in the model system and human colon. Low apical NHERF-1 intensity in CRC associated with disruption of glandular architecture, high cancer grade, and metastatic dissemination. We conclude that the membrane-binding function of the catalytically inert PTEN C2 domain influences cdc42/aPKC-dependent AM dynamics and gland formation in a highly relevant 3D CRC morphogenesis model system.

  8. Soluble VCAM-1 Alters Lipid Phosphatase Activity in Epicardial Mesothelial Cells: Implications for Lipid Signaling During Epicardial Formation

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    Robert W. Dettman

    2013-09-01

    Full Text Available Epicardial formation involves the attachment of proepicardial (PE cells to the heart and the superficial migration of mesothelial cells over the surface of the heart. Superficial migration has long been known to involve the interaction of integrins expressed by the epicardium and their ligands expressed by the myocardium; however, little is understood about signals that maintain the mesothelium as it migrates. One signaling pathway known to regulate junctional contacts in epithelia is the PI3K/Akt signaling pathway and this pathway can be modified by integrins. Here, we tested the hypothesis that the myocardially expressed, integrin ligand VCAM-1 modulates the activity of the PI3K/Akt signaling pathway by activating the lipid phosphatase activity of PTEN. We found that epicardial cells stimulated with a soluble form of VCAM-1 (sVCAM-1 reorganized PTEN from the cytoplasm to the membrane and nucleus and activated PTEN’s lipid phosphatase activity. Chick embryonic epicardial mesothelial cells (EMCs expressing a shRNA to PTEN increased invasion in collagen gels, but only after stimulation by TGFβ3, indicating that loss of PTEN is not sufficient to induce invasion. Expression of an activated form of PTEN was capable of blocking degradation of junctional complexes by TGFβ3. This suggested that PTEN plays a role in maintaining the mesothelial state of epicardium and not in EMT. We tested if altering PTEN activity could affect coronary vessel development and observed that embryonic chick hearts infected with a virus expressing activated human PTEN had fewer coronary vessels. Our data support a role for VCAM-1 in mediating critical steps in epicardial development through PTEN in epicardial cells.

  9. Posttranslational regulation of phosphatase and tensin homolog (PTEN and its functional impact on cancer behaviors

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    Xu WT

    2014-10-01

    Full Text Available Wenting Xu,1 Zhen Yang,1 Shu-Feng Zhou,2 Nonghua Lu1 1Department of Gastroenterology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, People’s Republic of China; 2Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida, Tampa, FL, USA Abstract: The incidence of cancer is increasing worldwide, but the biochemical mechanisms for the occurrence of cancer is not fully understood, and there is no cure for advanced tumors. Defects of posttranslational modifications of proteins are linked to a number of important diseases, such as cancer. This review will update our knowledge on the critical role of posttranscriptional regulation of phosphatase and tensin homolog (PTEN and its activities and the functional impact on cancer behaviors. PTEN is a tumor suppressor gene that occupies a key position in regulating cell growth, proliferation, apoptosis, mobility, signal transduction, and other crucial cellular processes. The activity and function of PTEN are regulated by coordinated epigenetic, transcriptional, posttranscriptional, and posttranslational modifications. In particular, PTEN is subject to phosphorylation, ubiquitylation, somoylation, acetylation, and active site oxidation. Posttranslational modifications of PTEN can dynamically change its activity and function. Deficiency in the posttranslational regulation of PTEN leads to abnormal cell proliferation, apoptosis, migration, and adhesion, which are associated with cancer initiation, progression, and metastasis. With increasing information on how PTEN is regulated by multiple mechanisms and networked proteins, its exact role in cancer initiation, growth, and metastasis will be revealed. PTEN and its functionally related proteins may represent useful targets for the discovery of new anticancer drugs, and gene therapy and the therapeutic potentials should be fully explored. Keywords: phosphorylation, ubiquitination, acetylation, oxidation

  10. Tumor suppressor PTEN affects tau phosphorylation: deficiency in the phosphatase activity of PTEN increases aggregation of an FTDP-17 mutant Tau

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    Zhang Xue

    2006-07-01

    Full Text Available Abstract Background Aberrant hyperphosphorylation of tau protein has been implicated in a variety of neurodegenerative disorders. Although a number of protein kinases have been shown to phosphorylate tau in vitro and in vivo, the molecular mechanisms by which tau phosphorylation is regulated pathophysiologically are largely unknown. Recently, a growing body of evidence suggests a link between tau phosphorylation and PI3K signaling. In this study, phosphorylation, aggregation and binding to the microtubule of a mutant frontal temporal dementia and parkinsonism linked to chromosome 17 (FTDP-17 tau in the presence of tumor suppressor PTEN, a major regulatory component in PI3K signaling, were investigated. Results Phosphorylation of the human mutant FTDP-17 tau, T40RW, was evaluated using different phospho-tau specific antibodies in the presence of human wild-type or phosphatase activity null mutant PTEN. Among the evaluated phosphorylation sites, the levels of Ser214 and Thr212 phospho-tau proteins were significantly decreased in the presence of wild-type PTEN, and significantly increased when the phosphatase activity null mutant PTEN was ectopically expressed. Fractionation of the mutant tau transfected cells revealed a significantly increased level of soluble tau in cytosol when wild-type PTEN was expressed, and an elevated level of SDS-soluble tau aggregates in the presence of the mutant PTEN. In addition, the filter/trap assays detected more SDS-insoluble mutant tau aggregates in the cells overexpressing the mutant PTEN compared to those in the cells overexpressing wild-type PTEN and control DNA. This notion was confirmed by the immunocytochemical experiment which demonstrated that the overexpression of the phosphatase activity null mutant PTEN caused the mutant tau to form aggregates in the COS-7 cells. Conclusion Tumor suppressor PTEN can alleviate the phosporylation of the mutant FTDP-17 tau at specific sites, and the phosphatase activity

  11. The Involvement of Phosphatase and Tensin Homolog Deleted on Chromosome Ten (PTEN in the Regulation of Inflammation Following Coronary Microembolization

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    Jiangyou Wang

    2014-06-01

    Full Text Available Background/Aims: Growing evidence shows that phosphatase and tensin homolog deleted on chromosome ten (PTEN is involved in regulating inflammation in different pathological conditions. Therefore, we hypothesized that the upregulation of PTEN correlates with the impairment of cardiac function in swine following coronary microembolization (CME. Methods: To possibly disclose an anti-inflammatory effect of PTEN, we induced swine CME by injecting inertia plastic microspheres (42 μm in diameter into the left anterior descending coronary artery and analyzed the myocardial tissue by immunochemistry, qRT-PCR and western blot analyses. In addition, we downregulated PTEN using siRNA. Results: Following CME, PTEN mRNA and protein levels were elevated as early as 3 h, peaked at 12 h, and then continuously decreased at 24 h and 48 h but remained elevated. Through linear correlation analysis, the PTEN protein level positively correlated with cTnI and TNF-α but was negatively correlated with LVEF. Furthermore, PTEN siRNA reduced the microinfarct volume, improved cardiac function (LVEF, reduced the release of cTnI, and suppressed PTEN and TNF-α protein expression. Conclusion: This study demonstrated, for the first time, that PTEN is involved in CME-induced inflammatory injury. The data generated from this study provide a rationale for the development of PTEN-based anti-inflammatory strategies.

  12. Combined Phosphatase and Tensin Homolog (PTEN Loss and Fatty Acid Synthase (FAS Overexpression Worsens the Prognosis of Chinese Patients with Hepatocellular Carcinoma

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    Xuehua Zhu

    2012-08-01

    Full Text Available We aimed to investigate the expression pattern of phosphatase and tensin homolog (PTEN, to evaluate the relationship between PTEN expression and clinicopathological characteristics, including fatty acid synthase (FAS expression, and to determine the correlations of PTEN and FAS expression with survival in Chinese patients with hepatocellular carcinoma (HCC. The expression patterns of PTEN and FAS were determined using tissue microarrays and immunohistochemistry. The expression of PTEN was compared with the clinicopathological characteristics of HCC, including FAS expression. Receiver operator characteristic curves were used to calculate the clinical sensitivity and specificity of PTEN expression. Kaplan-Meier survival curves were constructed to evaluate the correlations of PTEN loss and FAS overexpression with overall survival. We found that the loss of PTEN expression occurred predominantly in the cytoplasm, while FAS was mainly localized to the cytoplasm. Cytoplasmic and total PTEN expression levels were significantly decreased in HCC compared with adjacent non-neoplastic tissue (both, p < 0.0001. Decreased cytoplasmic and total PTEN expression showed significant clinical sensitivity and specificity for HCC (both, p < 0.0001. Downregulation of PTEN in HCC relative to non-neoplastic tissue was significantly correlated with histological grade (p = 0.043 for histological grades I–II versus grade III. Loss of total PTEN was significantly correlated with FAS overexpression (p = 0.014. Loss of PTEN was also associated with poor prognosis of patients with poorly differentiated HCC (p = 0.049. Moreover, loss of PTEN combined with FAS overexpression was associated with significantly worse prognosis compared with other HCC cases (p = 0.011. Our data indicate that PTEN may serve as a potential diagnostic and prognostic marker of HCC. Upregulating PTEN expression and inhibiting FAS

  13. PTEN in liver diseases and cancer

    Institute of Scientific and Technical Information of China (English)

    Marion; Peyrou; Lucie; Bourgoin; Michelangelo; Foti

    2010-01-01

    The phosphoinositide 3-kinase (PI3K)/phosphatase and tensin homolog (PTEN)/Akt axis is a key signal transduction node that regulates crucial cellular functions, including insulin and other growth factors signaling, lipid and glucose metabolism, as well as cell survival and apoptosis. In this pathway, PTEN acts as a phosphoinositide phosphatase, which terminates PI3Kpropagated signaling by dephosphorylating PtdIns(3,4)P2 and PtdIns(3,4,5)P3. However, the role of PTEN does not appear to be restricted only to ...

  14. Coordinate suppression of B cell lymphoma by PTEN and SHIP phosphatases

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    Miletic, Ana V; Anzelon-Mills, Amy N; Mills, David M

    2010-01-01

    results in lethal T cell lymphomas, we find that animals lacking PTEN or SHIP in B cells show no evidence of malignancy. However, concomitant deletion of PTEN and SHIP (bPTEN/SHIP(-/-)) results in spontaneous and lethal mature B cell neoplasms consistent with marginal zone lymphoma or, less frequently......, follicular or centroblastic lymphoma. bPTEN/SHIP(-/-) B cells exhibit enhanced survival and express more MCL1 and less Bim. These cells also express low amounts of p27(kip1) and high amounts of cyclin D3 and thus appear poised to undergo proliferative expansion. Unlike normal B cells, bPTEN/SHIP(-/-) B cells...... proliferate to the prosurvival factor B cell activating factor (BAFF). Interestingly, although BAFF availability may promote lymphoma progression, we demonstrate that BAFF is not required for the expansion of transferred bPTEN/SHIP(-/-) B cells. This study reveals that PTEN and SHIP act cooperatively...

  15. Dysregulation of AKT Pathway by SMYD2-Mediated Lysine Methylation on PTEN

    OpenAIRE

    Makoto Nakakido; Zhenzhong Deng; Takehiro Suzuki; Naoshi Dohmae; Yusuke Nakamura; Ryuji Hamamoto

    2015-01-01

    Phosphatase and tensin homologue (PTEN), one of the well-characterized tumor suppressor proteins, counteracts the phosphatidylinositol 3-kinase-AKT pathway through its unique lipid phosphatase activity. The functions of PTEN are regulated by a variety of posttranslational modifications such as acetylation, oxidation, ubiquitylation, phosphorylation, and SUMOylation. However, methylation of PTEN has not been reported so far. In this study, we demonstrated that the oncogenic protein lysine meth...

  16. Opening the conformation is a master switch for the dual localization and phosphatase activity of PTEN

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    Nguyen, Hoai-Nghia; Yang, Jr-Ming; Miyamoto, Takafumi; Itoh, Kie; Rho, Elmer; Zhang, Qiang; Inoue, Takanari; Devreotes, Peter N.; Sesaki, Hiromi; Iijima, Miho

    2015-01-01

    Tumor suppressor PTEN mainly functions at two subcellular locations, the plasma membrane and the nucleus. At the plasma membrane, PTEN dephosphorylates the tumorigenic second messenger PIP3, which drives cell proliferation and migration. In the nucleus, PTEN controls DNA repair and genome stability independently of PIP3. Whereas the concept that a conformational change regulates protein function through post-translational modifications has been well established in biology, it is unknown whether a conformational change simultaneously controls dual subcellular localizations of proteins. Here, we discovered that opening the conformation of PTEN is the crucial upstream event that determines its key dual localizations of this crucial tumor suppressor. We identify a critical conformational switch that regulates PTEN’s localization. Most PTEN molecules are held in the cytosol in a closed conformation by intramolecular interactions between the C-terminal tail and core region. Dephosphorylation of the tail opens the conformation and exposes the membrane-binding regulatory interface in the core region, recruiting PTEN to the membrane. Moreover, a lysine at residue 13 is also exposed and when ubiquitinated, transports PTEN to the nucleus. Thus, opening the conformation of PTEN is a key mechanism that enhances its dual localization and enzymatic activity, providing a potential therapeutic strategy in cancer treatments. PMID:26216063

  17. Identification of novel PTEN-binding partners: PTEN interaction with fatty acid binding protein FABP4.

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    Gorbenko, O; Panayotou, G; Zhyvoloup, A; Volkova, D; Gout, I; Filonenko, V

    2010-04-01

    PTEN is a tumor suppressor with dual protein and lipid-phosphatase activity, which is frequently deleted or mutated in many human advanced cancers. Recent studies have also demonstrated that PTEN is a promising target in type II diabetes and obesity treatment. Using C-terminal PTEN sequence in pEG202-NLS as bait, yeast two-hybrid screening on Mouse Embryo, Colon Cancer, and HeLa cDNA libraries was carried out. Isolated positive clones were validated by mating assay and identified through automated DNA sequencing and BLAST database searches. Sequence analysis revealed a number of PTEN-binding proteins linking this phosphatase to a number of different signaling cascades, suggesting that PTEN may perform other functions besides tumor-suppressing activity in different cell types. In particular, the interplay between PTEN function and adipocyte-specific fatty-acid-binding protein FABP4 is of notable interest. The demonstrable tautology of PTEN to FABP4 suggested a role for this phosphatase in the regulation of lipid metabolism and adipocyte differentiation. This interaction was further studied using coimmunoprecipitation and gel-filtration assays. Finally, based on Biacore assay, we have calculated the K(D) of PTEN-FABP4 complex, which is around 2.8 microM.

  18. A phosphatase-independent gain-of-function mutation in PTEN triggers aberrant cell growth in astrocytes through an autocrine IGF-1 loop.

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    Fernández, S; Genis, L; Torres-Alemán, I

    2014-08-07

    Loss-of-function mutations in the phosphatase PTEN (phosphatase and tensin homolog deleted on chromosome10) contribute to aberrant cell growth in part through upregulation of the mitogenic IGF-1/PI3K/Akt pathway. In turn, this pathway exerts a homeostatic feedback over PTEN. Using mutagenesis analysis to explore a possible impact of this mutual control on astrocyte growth, we found that truncation of the C-terminal region of PTEN (Δ51) associates with a marked increase in NFκB activity, a transcription factor overactivated in astrocyte tumors. Whereas mutations of PTEN are considered to lead to a loss-of-function, PTENΔ51, a truncation that comprises a region frequently mutated in human gliomas, displayed a neomorphic (gain-of-function) activity that was independent of its phosphatase activity. This gain-of-function of PTENΔ51 includes stimulation of IGF-1 synthesis through protein kinase A activation of the IGF-1 promoter. Increased IGF-1 originates an autocrine loop that activates Akt and NFκB. Constitutive activation of NFκB in PTENΔ51-expressing astrocytes leads to aberrant cell growth; astrocytes expressing this mutant PTEN generate colonies in vitro and tumors in vivo. Mutations converting a tumor suppressor such as PTEN into a tumor promoter through a gain-of-function involving IGF-1 production may further our understanding of the role played by this growth factor in glioma growth and help us define druggable targets for personalized therapy.

  19. Acid phosphatase and lipid peroxidation in human cataractous lens epithelium

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    Vasavada Abhay

    1993-01-01

    Full Text Available The anterior lens epithelial cells undergo a variety of degenerative and proliferative changes during cataract formation. Acid phosphatase is primarily responsible for tissue regeneration and tissue repair. The lipid hydroperoxides that are obtained by lipid peroxidation of polysaturated or unsaturated fatty acids bring about deterioration of biological membranes at cellular and tissue levels. Acid phosphatase and lipid peroxidation activities were studied on the lens epithelial cells of nuclear cataract, posterior subcapsular cataract, mature cataract, and mixed cataract. Of these, mature cataractous lens epithelium showed maximum activity for acid phosphatase (516.83 moles of p-nitrophenol released/g lens epithelium and maximum levels of lipid peroxidation (86.29 O.D./min/g lens epithelium. In contrast, mixed cataractous lens epithelium showed minimum activity of acid phosphatase (222.61 moles of p-nitrophenol released/g lens epithelium and minimum levels of lipid peroxidation (54.23 O.D./min/g lens epithelium. From our study, we correlated the maximum activity of acid phosphatase in mature cataractous lens epithelium with the increased areas of superimposed cells associated with the formation of mature cataract. Likewise, the maximum levels of lipid peroxidation in mature cataractous lens epithelium was correlated with increased permeability of the plasma membrane. Conversely, the minimum levels of lipid peroxidation in mixed cataractous lens epithelium makes us presume that factors other than lipid peroxidation may also account for the formation of mixed type of cataract.

  20. Identification of nucleolus-localized PTEN and its function in regulating ribosome biogenesis.

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    Li, Pingdong; Wang, Danni; Li, Haiyang; Yu, Zhenkun; Chen, Xiaohong; Fang, Jugao

    2014-10-01

    The tumor suppressor PTEN is a lipid phosphatase that is found mutated in different types of human cancers. PTEN suppresses cell proliferation by inhibiting the PI3K-Akt signaling pathway at the cell membrane. However, PTEN is also demonstrated to localize in the cell nucleus where it exhibits tumor suppressive activity via a different, unknown mechanism. In this study we report that PTEN also localizes to the nucleolus and that nucleolar PTEN plays an important role in regulating nucleolar homeostasis and maintaining nucleolar morphology. Overexpression of nuclear PTEN in PTEN null cells inhibits Akt phosphorylation and reduces cell size. Knockdown of PTEN in PTEN positive cells leads to nucleolar morphologic changes and an increase in the proportion of cells with a greater number of nucleoli. In addition, knockdown of PTEN in PTEN positive cells increased ribosome biogenesis. These findings expand current understanding of function and relevance of nuclear localized PTEN and provide a foundation for the development of novel therapies targeting PTEN.

  1. Cdc6 and Cyclin E2 Are PTEN-Regulated Genes Associated with Human Prostate Cancer Metastasis

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    Zhong Wu

    2009-01-01

    Full Text Available Phosphatase and tensin homolog deleted on chromosome 10 (PTEN is frequently inactivated in metastatic prostate cancer, yet the molecular consequences of this and their association with the metastatic phenotype are incompletely understood. We performed transcriptomic analysis and identified genes altered by conditional PTEN reexpression in C4-2, a human metastatic prostate cancer cell line with inactive PTEN. PTEN-regulated genes were disproportionately represented among genes altered in human prostate cancer progression and metastasis but not among those associated with tumorigenesis. From the former set, we identified two novel putative PTEN targets, cdc6 and cyclin E2, which were overexpressed in metastatic human prostate cancer and up-regulated as a function of PTEN depletion in poorly metastatic DU145 human prostate cancer cells harboring a wild type PTEN. Inhibition of cdc6 and cyclin E2 levels as a consequence of PTEN expression was associated with cell cycle G1 arrest, whereas use of PTEN activity mutants revealed that regulation of these genes was dependent on PTEN lipid phosphatase activity. Computational and promoter-reporter evaluations implicated the E2F transcription factor in PTEN regulation of cdc6 and cyclin E2 expression. Our results suggest a hypothetical model whereby PTEN loss upregulates cell cycle genes such as cdc6 and cyclin E2 that in turn promote metastatic colonization at distant sites.

  2. Characterization of a novel PTEN mutation in MDA-MB-453 breast carcinoma cell line

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    Singh Gobind

    2011-11-01

    Full Text Available Abstract Background Cowden Syndrome (CS patients with germ line point mutations in the PTEN gene are at high risk for developing breast cancer. It is believed that cells harboring these mutant PTEN alleles are predisposed to malignant conversion. This article will characterize the biochemical and biological properties of a mutant PTEN protein found in a commonly used metastatic breast cancer cell line. Methods The expression of PTEN in human breast carcinoma cell lines was evaluated by Western blotting analysis. Cell line MDA-MB-453 was selected for further analysis. Mutation analysis of the PTEN gene was carried out using DNA isolated from MDA-MB-453. Site-directed mutagenesis was used to generate a PTEN E307K mutant cDNA and ectopic expressed in PC3, U87MG, MCF7 and Pten-/- mouse embryo fibroblasts (MEFS. Histidine (His-tagged PTEN fusion protein was generated in Sf9 baculovirus expression system. Lipid phosphatase and ubiquitination assays were carried out to characterize the biochemical properties of PTEN E307K mutant. The intracellular localization of PTEN E307K was determined by subcellular fractionation experiments. The ability of PTEN E307K to alter cell growth, migration and apoptosis was analyzed in multiple PTEN-null cell lines. Results We found a mutation in the PTEN gene at codon 307 in MDA-MB-453 cell line. The glutamate (E to lysine (K substitution rendered the mutant protein to migrate with a faster mobility on SDS-PAGE gels. Biochemically, the PTEN E307K mutant displayed similar lipid phosphatase and growth suppressing activities when compared to wild-type (WT protein. However, the PTEN E307K mutant was present at higher levels in the membrane fraction and suppressed Akt activation to a greater extent than the WT protein. Additionally, the PTEN E307K mutant was polyubiquitinated to a greater extent by NEDD4-1 and displayed reduced nuclear localization. Finally, the PTEN E307K mutant failed to confer chemosensitivity to

  3. Subcellular targeting and dynamic regulation of PTEN: Implications for neuronal cells and neurological disorders

    Directory of Open Access Journals (Sweden)

    Patricia eKreis

    2014-04-01

    Full Text Available PTEN is a lipid and protein phosphatase that regulates a diverse range of cellular mechanisms. PTEN is mainly present in the cytosol and transiently associates with the plasma membrane to dephosphorylate PI(3,4,5P3, thereby antagonizing the PI3-Kinase signaling pathway. Recently, PTEN has been shown to associate also with organelles such as the endoplasmic reticulum, the mitochondria or the nucleus, and to be secreted outside of the cell. In addition, PTEN dynamically localizes to specialized sub-cellular compartments such as the neuronal growth cone or dendritic spines. The diverse localizations of PTEN imply a tight temporal and spatial regulation, orchestrated by mechanisms such as posttranslational modifications, formation of distinct protein-protein interactions or the activation/recruitment of PTEN downstream of external cues. The regulation of PTEN function is thus not only important at the enzymatic activity level, but is also associated to its spatial distribution. In this review we will summarize (i recent findings that highlight mechanisms controlling PTEN movement and sub-cellular localization, and (ii current understanding of how PTEN localization is achieved by mechanisms controlling posttranslational modification, by association with binding partners and by PTEN structural or activity requirements. Finally, we will discuss the possible roles of compartmentalized PTEN in developing and mature neurons in health and disease.

  4. Mesodermal Pten inactivation leads to alveolar capillary dysplasia- like phenotype.

    Science.gov (United States)

    Tiozzo, Caterina; Carraro, Gianni; Al Alam, Denise; Baptista, Sheryl; Danopoulos, Soula; Li, Aimin; Lavarreda-Pearce, Maria; Li, Changgong; De Langhe, Stijn; Chan, Belinda; Borok, Zea; Bellusci, Saverio; Minoo, Parviz

    2012-11-01

    Alveolar capillary dysplasia (ACD) is a congenital, lethal disorder of the pulmonary vasculature. Phosphatase and tensin homologue deleted from chromosome 10 (Pten) encodes a lipid phosphatase controlling key cellular functions, including stem/progenitor cell proliferation and differentiation; however, the role of PTEN in mesodermal lung cell lineage formation remains unexamined. To determine the role of mesodermal PTEN in the ontogeny of various mesenchymal cell lineages during lung development, we specifically deleted Pten in early embryonic lung mesenchyme in mice. Pups lacking Pten died at birth, with evidence of failure in blood oxygenation. Analysis at the cellular level showed defects in angioblast differentiation to endothelial cells and an accompanying accumulation of the angioblast cell population that was associated with disorganized capillary beds. We also found decreased expression of Forkhead box protein F1 (Foxf1), a gene associated with the ACD human phenotype. Analysis of human samples for ACD revealed a significant decrease in PTEN and increased activated protein kinase B (AKT). These studies demonstrate that mesodermal PTEN has a key role in controlling the amplification of angioblasts as well as their differentiation into endothelial cells, thereby directing the establishment of a functional gas exchange interface. Additionally, these mice could serve as a murine model of ACD.

  5. MyosinV controls PTEN function and neuronal cell size.

    Science.gov (United States)

    van Diepen, Michiel T; Parsons, Maddy; Downes, C Peter; Leslie, Nicholas R; Hindges, Robert; Eickholt, Britta J

    2009-10-01

    The tumour suppressor PTEN can inhibit cell proliferation and migration as well as control cell growth, in different cell types. PTEN functions predominately as a lipid phosphatase, converting PtdIns(3,4,5)P(3) to PtdIns(4,5)P(2), thereby antagonizing PI(3)K (phosphoinositide 3-kinase) and its established downstream effector pathways. However, much is unclear concerning the mechanisms that regulate PTEN movement to the cell membrane, which is necessary for its activity towards PtdIns(3,4,5)P(3) (Refs 3, 4, 5). Here we show a requirement for functional motor proteins in the control of PI3K signalling, involving a previously unknown association between PTEN and myosinV. FRET (Förster resonance energy transfer) measurements revealed that PTEN interacts directly with myosinV, which is dependent on PTEN phosphorylation mediated by CK2 and/or GSK3. Inactivation of myosinV-transport function in neurons increased cell size, which, in line with known attributes of PTEN-loss, required PI(3)K and mTor. Our data demonstrate a myosin-based transport mechanism that regulates PTEN function, providing new insights into the signalling networks regulating cell growth.

  6. Active β-catenin is regulated by the PTEN/PI3 kinase pathway: a role for protein phosphatase PP2A

    Science.gov (United States)

    Persad, Amit; Venkateswaran, Geetha; Hao, Li; Garcia, Maria E.; Yoon, Jenny; Sidhu, Jaskiran; Persad, Sujata

    2016-01-01

    Dysregulation of Wnt/β-catenin signaling has been associated with the development and progression of many cancers. The stability and subcellular localization of β-catenin, a dual functional protein that plays a role in intracellular adhesion and in regulating gene expression, is tightly regulated. However, little is known about the transcriptionally active form of β-catenin, Active Beta Catenin (ABC), that is unphosphorylated at serine 37 (Ser37) and threonine 41 (Thr41). Elucidating the mechanism by which β-catenin is activated to generate ABC is vital to the development of therapeutic strategies to block β-catenin signaling for cancer treatment. Using melanoma, breast and prostate cancer cell lines, we show that while cellular β-catenin levels are regulated by the Wnt pathway, cellular ABC levels are mainly regulated by the PI3K pathway and are dependent on the phosphatase activity of the protein phosphatase PP2A. Furthermore, we demonstrate that although the PI3K/PTEN pathway does not regulate total β-catenin protein levels within the cell, it plays a role in regulating the subcellular localization of β-catenin. Our results support a novel functional interaction/cross-talk between the PTEN/PI3K and Wnt pathways in the regulation of the subcellular/nuclear levels of ABC, which is crucially important for the protein's activity as a transcription factor and its biological effects in health and disease.

  7. Comparative phytohormone profiles, lipid kinase and lipid phosphatase activities in barley aleurone, coleoptile, and root tissues.

    Science.gov (United States)

    Meringer, Maria V; Villasuso, Ana L; Pasquaré, Susana J; Giusto, Norma M; Machado, Estela E; Racagni, Graciela E

    2012-09-01

    We analyzed lipid kinase and lipid phosphatase activities and determined endogenous phytohormone levels by liquid chromatography-tandem mass spectrometry in root and coleoptile tissues following germination of barley (Hordeum vulgare) seeds. The enzymes showing highest activity in aleurone cells were diacylglycerol kinase (DAG-k, EC 2.7.1.107) and phosphatidate kinase (PA-k). The ratio of gibberellins (GAs) to abscisic acid (ABA) was 2-fold higher in aleurone than in coleoptile or root tissues. In coleoptiles, phosphatidylinositol 4-kinase (PI4-k, EC 2.7.1.67) showed the highest enzyme activity, and jasmonic acid (JA) level was higher than in aleurone. In roots, activities of PI4-k, DAG-k, and PA-k were similar, and salicylic acid (SA) showed the highest concentration. In the assays to evaluate the hydrolysis of DGPP (diacylglycerol pyrophosphate) and PA (phosphatidic acid) we observed that PA hydrolysis by LPPs (lipid phosphate phosphatases) was not modified; however, the diacylglycerol pyrophosphate phosphatase (DGPPase) was strikingly higher in coleoptile and root tissues than to aleurone. Relevance of these findings in terms of signaling responses and seedling growth is discussed.

  8. PTEN at 18: Still Growing.

    Science.gov (United States)

    Gorbenko, Olena; Stambolic, Vuk

    2016-01-01

    Discovered in 1997, PTEN remains one of the most studied tumor suppressors. In this issue of Methods in Molecular Biology, we assembled a series of papers describing various clinical and experimental approaches to studying PTEN function. Due to its broad expression, regulated subcellular localization, and intriguing phosphatase activity, methodologies aimed at PTEN study have often been developed in the context of mutations affecting various aspects of its regulation, found in patients burdened with PTEN loss-driven tumors. PTEN's extensive posttranslational modifications and dynamic localization pose unique challenges for studying PTEN features in isolation and necessitate considerable development of experimental systems to enable controlled characterization. Nevertheless, ongoing efforts towards the development of PTEN knockout and knock-in animals and cell lines, antibodies, and enzymatic assays have facilitated a huge body of work, which continues to unravel the fascinating biology of PTEN.

  9. Differential Expression and Clinical Significance of DNA Methyltransferase 3B (DNMT3B), Phosphatase and Tensin Homolog (PTEN) and Human MutL Homologs 1 (hMLH1) in Endometrial Carcinomas.

    Science.gov (United States)

    Li, Wenting; Wang, Ying; Fang, Xinzhi; Zhou, Mei; Li, Yiqun; Dong, Ying; Wang, Ruozheng

    2017-02-21

    BACKGROUND The aim of this study was to investigate the expression and the clinicopathologic significance of DNA methyltransferase 3B (DNMT3B), phosphatase and tensin homolog (PTEN) and human MutL homologs 1 (hMLH1) in endometrial carcinomas between Han and Uygur women in Xinjiang. MATERIAL AND METHODS The expression of DNMT3B, PTEN, and hMLH1 in endometrial carcinomas were assessed by immunohistochemistry, followed by an analysis of their relationship to clinical-pathological features and prognosis. RESULTS There were a 61.7% (95/154) overexpression of DNMT3B, 50.0% (77/154) loss of PTEN expression and 18.2% (28/154) loss of hMLH1 expression. The expression of DNMT3B and PTEN in endometrial carcinomas was statistically significantly different between Uygur women and Han women (p=0.001, p=0.010, respectively). DNMT3B expression was statistically significant based on the grade of endometrial carcinomas (p=0.031). PTEN loss was statistically significant between endometrioid carcinomas (ECs) and non endometrioid carcinomas (NECs) (p=0.040). DNMT3B expression was statistically significant in different myometrial invasion groups in Uygur women (p=0.010). Furthermore, the correlation of DNMT3B and PTEN expression was significant in endometrial carcinomas (p=0.021). PTEN expression was statistically significant in the overall survival (OS) rate of women with endometrial cancers (p=0.041). CONCLUSIONS Our findings suggest that PTEN and DNMT3B possess common regulation features as well as certain ethnic differences in expression between Han women and Uygur women. An interaction may exist in the pathogenesis of endometrial carcinoma. DNMT3B was expressed differently in cases of myometrial invasion and PTEN was associated with OS, which suggested that these molecular markers may be useful in the evaluation of the biological behavior of endometrial carcinomas and may be useful indicators of prognosis in women with endometrial carcinomas.

  10. Ginkgolic Acid C 17:1, Derived from Ginkgo biloba Leaves, Suppresses Constitutive and Inducible STAT3 Activation through Induction of PTEN and SHP-1 Tyrosine Phosphatase

    Directory of Open Access Journals (Sweden)

    Seung Ho Baek

    2017-02-01

    Full Text Available Ginkgolic acid C 17:1 (GAC 17:1 extracted from Ginkgo biloba leaves, has been previously reported to exhibit diverse antitumor effect(s through modulation of several molecular targets in tumor cells, however the detailed mechanism(s of its actions still remains to be elucidated. Signal transducer and activator of transcription 3 (STAT3 is an oncogenic transcription factor that regulates various critical functions involved in progression of diverse hematological malignancies, including multiple myeloma, therefore attenuating STAT3 activation may have a potential in cancer therapy. We determined the anti-tumor mechanism of GAC 17:1 with respect to its effect on STAT3 signaling pathway in multiple myeloma cell lines. We found that GAC 17:1 can inhibit constitutive activation of STAT3 through the abrogation of upstream JAK2, Src but not of JAK1 kinases in U266 cells and also found that GAC can suppress IL-6-induced STAT3 phosphorylation in MM.1S cells. Treatment of protein tyrosine phosphatase (PTP inhibitor blocked suppression of STAT3 phosphorylation by GAC 17:1, thereby indicating a critical role for a PTP. We also demonstrate that GAC 17:1 can induce the substantial expression of PTEN and SHP-1 at both protein and mRNA level. Further, deletion of PTEN and SHP-1 genes by siRNA can repress the induction of PTEN and SHP-1, as well as abolished the inhibitory effect of drug on STAT3 phosphorylation. GAC 17:1 down-regulated the expression of STAT3 regulated gene products and induced apoptosis of tumor cells. Overall, GAC 17:1 was found to abrogate STAT3 signaling pathway and thus exert its anticancer effects against multiple myeloma cells.

  11. PTEN, a widely known negative regulator of insulin/PI3K signaling, positively regulates neuronal insulin resistance

    Science.gov (United States)

    Gupta, Amit; Dey, Chinmoy Sankar

    2012-01-01

    Lipid and protein tyrosine phosphatase, phosphatase and tension homologue (PTEN), is a widely known negative regulator of insulin/phosphoinositide 3-kinase signaling. Down-regulation of PTEN is thus widely documented to ameliorate insulin resistance in peripheral tissues such as skeletal muscle and adipose. However, not much is known about its exact role in neuronal insulin signaling and insulin resistance. Moreover, alterations of PTEN in neuronal systems have led to discovery of several unexpected outcomes, including in the neurodegenerative disorder Alzheimer's disease (AD), which is increasingly being recognized as a brain-specific form of diabetes. In addition, contrary to expectations, its neuron-specific deletion in mice resulted in development of diet-sensitive obesity. The present study shows that PTEN, paradoxically, positively regulates neuronal insulin signaling and glucose uptake. Its down-regulation exacerbates neuronal insulin resistance. The positive role of PTEN in neuronal insulin signaling is likely due to its protein phosphatase actions, which prevents the activation of focal adhesion kinase (FAK) and extracellular signal-regulated kinase (ERK), the kinases critically involved in neuronal energy impairment and neurodegeneration. Results suggest that PTEN acting through FAK, the direct protein substrate of PTEN, prevents ERK activation. Our findings provide an explanation for unexpected outcomes reported earlier with PTEN alterations in neuronal systems and also suggest a novel molecular pathway linking neuronal insulin resistance and AD, the two pathophysiological states demonstrated to be closely linked. PMID:22875989

  12. What controls PTEN and what it controls (in prostate cancer)

    Institute of Scientific and Technical Information of China (English)

    Paramita M Ghosh

    2012-01-01

    The standard of care for metastatic prostate cancer (PCa) is androgen deprivation therapy since almost all PCa growth is initially reliant on the androgen receptor (AR).However,almost all patients develop resistance to this therapy within 18-24months,and current treatment for castration-resistant prostate cancer (CRPC) is extremely limited,despite the advent of new drugs that target the AR,such as ahiraterone and MDV3100.1 Multiple studies have associated the loss of phosphatase and tensin homolog deleted on chromosome 10(PTEN),a dual lipid and protein phosphatase that is frequently lost in prostate cancer,with the development of CRPC.2,3 Yet,multiple studies have shown that at least 20%-40%of primary PCa,which are almost always androgen sensitive,experience a loss of PTEN,4,5 while as many as 30% of CRPC tumors are PTEN-positive.6 The broad questions then facing researchers are:(i) How does PTEN loss cause CRPC?;(ii) What is the mechanism of CRPC development in PTEN+/+ tumors?;and (iii) How can CRPC tumors be inhibited in PTEN-null cells?Three new publications in recent times have come up with mechanisms that answer these questions.7-9 Two of these,both in Cancer Cell eadier this year,from the laboratories of Dr Charles Sawyers and Dr Hong Wu,address a novel negative feedback regulation between AR and PTEN,and all three,including the one from Dr Damu Tang,show that the loss of PTEN function is likely the first step towards the development of CRPC.

  13. Sphingosylphosphorylcholine protects cardiomyocytes against ischemic apoptosis via lipid raft/PTEN/Akt1/mTOR mediated autophagy.

    Science.gov (United States)

    Yue, Hong-Wei; Liu, Jing; Liu, Ping-Ping; Li, Wen-Jing; Chang, Fen; Miao, Jun-Ying; Zhao, Jing

    2015-09-01

    Autophagy, evoked by diverse stresses including myocardial ischemia/reperfusion (I/R), profoundly affects the development of heart failure. However, the specific molecular basis of autophagy remains to be elucidated. Here we report that sphingosylphosphorylcholine (SPC), a bioactive sphingolipid, significantly suppressed apoptosis and induced autophagy in cardiomyocytes. Blocking this SPC evoked autophagy by 3-methyladenine (3MA)-sensitized cardiomyocytes to serum deprivation-induced apoptosis. Subsequent studies revealed that SPC downregulated the phosphorylation of p70S6K and 4EBP1 (two substrates of mTOR) but enhanced that of JNK when inducing autophagy. We identified SPC as a switch for the activity of Akt1, a supposed upstream modulator of both mTOR and JNK. Furthermore, β-cyclodextrin, which destroys membrane cholesterol, abolished the SPC-reduced phosphorylation of both Akt and PTEN, thus inhibiting SPC-induced autophagy. In conclusion, SPC is a novel molecule protecting cardiomyocytes against apoptosis by promoting autophagy. The lipid raft/PTEN/Akt1/mTOR signal pathway is the underlying mechanism and might provide novel targets for cardiac failure therapy.

  14. PTEN function: the long and the short of it.

    Science.gov (United States)

    Hopkins, Benjamin D; Hodakoski, Cindy; Barrows, Douglas; Mense, Sarah M; Parsons, Ramon E

    2014-04-01

    Phosphatase and tensin homolog deleted on chromosome ten (PTEN) is a phosphatase that is frequently altered in cancer. PTEN has phosphatase-dependent and -independent roles, and genetic alterations in PTEN lead to deregulation of protein synthesis, the cell cycle, migration, growth, DNA repair, and survival signaling. PTEN localization, stability, conformation, and phosphatase activity are controlled by an array of protein-protein interactions and post-translational modifications. Thus, PTEN-interacting and -modifying proteins have profound effects on the tumor suppressive functions of PTEN. Moreover, recent studies identified mechanisms by which PTEN can exit cells, via either exosomal export or secretion, and act on neighboring cells. This review focuses on modes of PTEN protein regulation and ways in which perturbations in this regulation may lead to disease.

  15. Genetic and cell biological aspects of PTEN in prostate cancer

    NARCIS (Netherlands)

    P.W. van Duijn (Petra)

    2008-01-01

    textabstractThe dual specific phosphatase PTEN (Phosphatase and TENsin homolog deleted on chromosome 10) is one of the most extensively studied proteins of the last decade. It was the first phosphatase identified as a tumor suppressor and in sporadic cancers PTEN is one of the most frequently altere

  16. PTEN dephosphorylates AKT to prevent the expression of GLUT1 on plasmamembrane and to limit glucose consumption in cancer cells.

    Science.gov (United States)

    Phadngam, Suratchanee; Castiglioni, Andrea; Ferraresi, Alessandra; Morani, Federica; Follo, Carlo; Isidoro, Ciro

    2016-12-20

    GLUT1 is the facilitative transporter playing the major role in the internalization of glucose. Basally, GLUT1 resides on vesicles located in a para-golgian area, and is translocated onto the plasmamembrane upon activation of the PI3KC1-AKT pathway. In proliferating cancer cells, which demand a high quantity of glucose for their metabolism, GLUT1 is permanently expressed on the plasmamembrane. This is associated with the abnormal activation of the PI3KC1-AKT pathway, consequent to the mutational activation of PI3KC1 and/or the loss of PTEN. The latter, in fact, could antagonize the phosphorylation of AKT by limiting the availability of Phosphatidylinositol (3,4,5)-trisphosphate. Here, we asked whether PTEN could control the plasmamembrane expression of GLUT1 also through its protein-phosphatase activity on AKT. Experiments of co-immunoprecipitation and in vitro de-phosphorylation assay with homogenates of cells transgenically expressing the wild type or knocked-down mutants (lipid-phosphatase, protein-phosphatase, or both) isoforms demonstrated that indeed PTEN physically interacts with AKT and drives its dephosphorylation, and so limiting the expression of GLUT1 at the plasmamembrane. We also show that growth factors limit the ability of PTEN to dephosphorylate AKT. Our data emphasize the fact that PTEN acts in two distinct steps of the PI3k/AKT pathway to control the expression of GLUT1 at the plasmamembrane and, further, add AKT to the list of the protein substrates of PTEN.

  17. PTEN function, the long and the short of it

    Science.gov (United States)

    Hopkins, Benjamin D.; Hodakoski, Cindy; Barrows, Doug; Mense, Sarah; Parsons, Ramon E.

    2014-01-01

    Phosphatase and tensin homolog deleted on chromosome ten (PTEN) is a phosphatase that is frequently altered in cancer. PTEN has phosphatase-dependent and - independent roles; and genetic alterations in PTEN lead to deregulation of protein synthesis, cell cycle, migration, growth, DNA repair, and survival signaling. PTEN localization, stability, conformation, and phosphatase activity are controlled by an array of protein-protein interactions and post-translational modifications. Thus, PTEN-interacting and modifying proteins have profound effects on PTEN’s tumor suppressive functions. Moreover, recent studies identified mechanisms by which PTEN can exit cells, either via exosomal export or secretion, and act on neighboring cells. This review focuses on modes of PTEN protein regulation and ways in which perturbations in this regulation may lead to disease. PMID:24656806

  18. PPARγ, PTEN, and the Fight against Cancer

    OpenAIRE

    Teresi, Rosemary E.; Kristin A. Waite

    2008-01-01

    Peroxisome proliferator-activated receptor gamma (PPAR ) is a ligand-activated transcription factor, which belongs to the family of nuclear hormone receptors. Recent in vitro studies have shown that PPAR can regulate the transcription of phosphatase and tensin homolog on chromosome ten (PTEN), a known tumor suppressor. PTEN is a susceptibility gene for a number of disorders, including breast and thyroid cancer. Activation of PPAR through agonists increases functional PTEN protein levels...

  19. Regulation of hematopoietic cell function by inhibitory immunoglobulin G receptors and their inositol lipid phosphatase effectors.

    Science.gov (United States)

    Cady, Carol T; Rice, Jeffrey S; Ott, Vanessa L; Cambier, John C

    2008-08-01

    Numerous autoimmune and inflammatory disorders stem from the dysregulation of hematopoietic cell activation. The activity of inositol lipid and protein tyrosine phosphatases, and the receptors that recruit them, is critical for prevention of these disorders. Balanced signaling by inhibitory and activating receptors is now recognized to be an important factor in tuning cell function and inflammatory potential. In this review, we provide an overview of current knowledge of membrane proximal events in signaling by inhibitory/regulatory receptors focusing on structural and functional characteristics of receptors and their effectors Src homology 2 (SH2) domain-containing tyrosine phosphatase 1 and SH2 domain-containing inositol 5-phosphatase-1. We review use of new strategies to identify novel regulatory receptors and effectors. Finally, we discuss complementary actions of paired inhibitory and activating receptors, using Fc gammaRIIA and Fc gammaRIIB regulation human basophil activation as a prototype.

  20. Lipid mobilization and acid phosphatase activity in lytic compartments during conidium dormancy and appressorium formation of Colletotrichum graminicola.

    Science.gov (United States)

    Schadeck, R J; Leite, B; de Freitas Buchi, D

    1998-12-01

    Colletotrichum graminicola, a pathogen of sorghum and corn, was investigated prior and during germination as to certain aspects of acid phosphatase activity and lipid mobilization. Ungerminated conidia cytoplasm was filled with lipid deposits, which were mobilized during the germination process. Cytochemical ultrastructural examination showed that conidia vacuoles exhibit acid phosphatase activity, which is suggestive of lytic activity. Lipid bodies, stored in the ungerminated conidia cytoplasm, were internalized by vacuoles in a process analogous to microautophagy and were apparently digested inside them. The lipid bodies disappeared and vacuoles became enlarged in conidial cells during germination. Appressoria also showed acid phosphatase activity in multiple heterogeneous vesicles which were, in most cases, juxtaposed with lipid bodies. These results suggest that the vacuolar system plays an important role during C. graminicola germination and that the initial stages of lipid metabolization are taking place inside the vacuoles.

  1. Can we accurately report PTEN status in advanced colorectal cancer?

    OpenAIRE

    Hocking, Christopher; Hardingham, Jennifer E.; Broadbridge, Vy; Wrin, Joe; Townsend, Amanda R; Tebbutt, Niall; Cooper, John; Ruszkiewicz, Andrew; Lee, Chee; Price, Timothy J.

    2014-01-01

    Background Loss of phosphatase and tensin homologue (PTEN) function evaluated by loss of PTEN protein expression on immunohistochemistry (IHC) has been reported as both prognostic in metastatic colorectal cancer and predictive of response to anti-EGFR monoclonal antibodies although results remain uncertain. Difficulties in the methodological assessment of PTEN are likely to be a major contributor to recent conflicting results. Methods We assessed loss of PTEN function in 51 colorectal cancer ...

  2. PTEN regulates colorectal epithelial apoptosis through Cdc42 signalling

    OpenAIRE

    Deevi, R; A. Fatehullah; Jagan, I; Nagaraju, M; Bingham, V; Campbell, F C

    2011-01-01

    Background: Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) regulation of the Rho-like GTPase Cdc42 has a central role in epithelial polarised growth, but effects of this molecular network on apoptosis remain unclear. Methods: To investigate the role of Cdc42 in PTEN-dependent cell death, we used flow cytometry, in vitro pull-down assays, poly(ADP ribose) polymerase (PARP) cleavage and other immunoblots in isogenic PTEN-expressing and -deficient colorectal cells (HCT116PTEN+/...

  3. Poly-ADP ribosylation of PTEN by tankyrases promotes PTEN degradation and tumor growth

    Science.gov (United States)

    Li, Nan; Zhang, Yajie; Han, Xin; Liang, Ke; Wang, Jiadong; Feng, Lin; Wang, Wenqi; Songyang, Zhou; Lin, Chunru; Yang, Liuqing; Yu, Yonghao

    2015-01-01

    PTEN [phosphatidylinositol (3,4,5)-trisphosphate phosphatase and tensin homolog deleted from chromosome 10], a phosphatase and critical tumor suppressor, is regulated by numerous post-translational modifications, including phosphorylation, ubiquitination, acetylation, and SUMOylation, which affect PTEN localization and protein stability. Here we report ADP-ribosylation as a new post-translational modification of PTEN. We identified PTEN as a novel substrate of tankyrases, which are members of the poly(ADP-ribose) polymerases (PARPs). We showed that tankyrases interact with and ribosylate PTEN, which promotes the recognition of PTEN by a PAR-binding E3 ubiquitin ligase, RNF146, leading to PTEN ubiquitination and degradation. Double knockdown of tankyrase1/2 stabilized PTEN, resulting in the subsequent down-regulation of AKT phosphorylation and thus suppressed cell proliferation and glycolysis in vitro and tumor growth in vivo. Furthermore, tankyrases were up-regulated and negatively correlated with PTEN expression in human colon carcinomas. Together, our study revealed a new regulation of PTEN and highlighted a role for tankyrases in the PTEN–AKT pathway that can be explored further for cancer treatment. PMID:25547115

  4. Genomic rearrangements of PTEN in prostate cancer

    Directory of Open Access Journals (Sweden)

    Sopheap ePhin

    2013-09-01

    Full Text Available The phosphatase and tensin homolog gene on chromosome 10q23.3 (PTEN is a negative regulator of the PIK3/Akt survival pathway and is the most frequently deleted tumor suppressor gene in prostate cancer. Monoallelic loss of PTEN is present in up to 60% of localized prostate cancers and complete loss of PTEN in prostate cancer is linked to metastasis and androgen independent progression. Studies on the genomic status of PTEN in prostate cancer initially used a two-color fluorescence in-situ hybridization (FISH assay for PTEN copy number detection in formalin fixed paraffin embedded tissue preparations. More recently, a four-color FISH assay containing two additional control probes flanking the PTEN locus with a lower false-positive rate was reported. Combined with the detection of other critical genomic biomarkers for prostate cancer such as ERG, AR, and MYC, the evaluation of PTEN genomic status has proven to be invaluable for patient stratification and management. Although less frequent than allelic deletions, point mutations in the gene and epigenetic silencing are also known to contribute to loss of PTEN function, and ultimately to prostate cancer initiation. Overall, it is clear that PTEN is a powerful biomarker for prostate cancer. Used as a companion diagnostic for emerging therapeutic drugs, FISH analysis of PTEN is promisingly moving human prostate cancer closer to more effective cancer management and therapies.

  5. Hypoxia-induced modulation of PTEN activity and EMT phenotypes in lung cancers.

    Science.gov (United States)

    Kohnoh, Takashi; Hashimoto, Naozumi; Ando, Akira; Sakamoto, Koji; Miyazaki, Shinichi; Aoyama, Daisuke; Kusunose, Masaaki; Kimura, Motohiro; Omote, Norihito; Imaizumi, Kazuyoshi; Kawabe, Tsutomu; Hasegawa, Yoshinori

    2016-01-01

    Persistent hypoxia stimulation, one of the most critical microenvironmental factors, accelerates the acquisition of epithelial-mesenchymal transition (EMT) phenotypes in lung cancer cells. Loss of phosphatase and tensin homologue deleted from chromosome 10 (PTEN) expression might accelerate the development of lung cancer in vivo. Recent studies suggest that tumor microenvironmental factors might modulate the PTEN activity though a decrease in total PTEN expression and an increase in phosphorylation of the PTEN C-terminus (p-PTEN), resulting in the acquisition of the EMT phenotypes. Nevertheless, it is not known whether persistent hypoxia can modulate PTEN phosphatase activity or whether hypoxia-induced EMT phenotypes are negatively regulated by the PTEN phosphatase activity. We aimed to investigate hypoxia-induced modulation of PTEN activity and EMT phenotypes in lung cancers. Western blotting was performed in five lung cancer cell lines to evaluate total PTEN expression levels and the PTEN activation. In a xenograft model of lung cancer cells with endogenous PTEN expression, the PTEN expression was evaluated by immunohistochemistry. To examine the effect of hypoxia on phenotypic alterations in lung cancer cells in vitro, the cells were cultured under hypoxia. The effect of unphosphorylated PTEN (PTEN4A) induction on hypoxia-induced EMT phenotypes was evaluated, by using a Dox-dependent gene expression system. Lung cancer cells involving the EMT phenotypes showed a decrease in total PTEN expression and an increase in p-PTEN. In a xenograft model, loss of PTEN expression was observed in the tumor lesions showing tissue hypoxia. Persistent hypoxia yielded an approximately eight-fold increase in the p-PTEN/PTEN ratio in vitro. PTEN4A did not affect stabilization of hypoxia-inducible factor 1α. PTEN4A blunted hypoxia-induced EMT via inhibition of β-catenin translocation into the cytoplasm and nucleus. Our study strengthens the therapeutic possibility that

  6. PTEN degradation after ischemic stroke: a double-edged sword.

    Science.gov (United States)

    Li, W; Huang, R; Chen, Z; Yan, L-J; Simpkins, J W; Yang, S-H

    2014-08-22

    Tumor suppressor phosphatase and tensin homolog (PTEN) is highly expressed in neurons and PTEN inhibition has been reported to be neuroprotective against ischemic stroke in experimental models. On the other hand, PTEN deletion has been shown to lead to cognitive impairment. In the current study, we examined the expression and functions of PTEN in an ischemic stroke rodent model. We found rapid S-nitrosylation and degradation of PTEN after cerebral ischemia/reperfusion injury. PTEN degradation leads to activation of Akt. PTEN partial deletion or PTEN inhibition increased the expression of GABAA receptor (GABAAR) γ2 subunit and enhanced GABAA receptor current. After cerebral ischemia, increased expression of GABAAR γ2 subunit was observed in the ischemia region and the penumbra area. We also observed PTEN loss in astrocytes after cerebral ischemia. Astrocytic PTEN partial knockout increased astrocyte activation and exacerbated ischemic damage. We speculated that ischemic stroke induced neuronal PTEN degradation, hence enhanced GABAA receptor-medicated neuronal activity inhibition which could attenuate excitotoxicity and provide neuroprotection during the acute phase after stroke, while inhibiting long-term functional recovery and contributing to vascular cognitive impairment after stroke. On the other hand, ischemic stroke induced astrocytic PTEN loss and enhanced ischemic damage and astrogliosis. Taken together, our study indicates that ischemic stroke induces rapid PTEN degradation in both neurons and astrocytes which play both protective and detrimental action in a spatiotemporal- and cell-type-dependent manner. Our study provides critical insight for targeting PTEN signaling pathway for stroke treatment.

  7. Nuclear PTEN controls DNA repair and sensitivity to genotoxic stress

    Science.gov (United States)

    Bassi, C; Ho, J; Srikumar, T; Dowling, RJO; Gorrini, C; Miller, SJ; Mak, TW; Neel, BG; Raught, B; Stambolic, V

    2016-01-01

    Loss of function of the Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) tumor suppressor gene is associated with many human cancers. In the cytoplasm, PTEN antagonizes the Phosphatidylinositol 3′ kinase (PI3K) signaling pathway. PTEN also accumulates in the nucleus, where its function remains poorly understood. We demonstrate that SUMOylation (SUMO) of PTEN controls its nuclear localization. In cells exposed to genotoxic stress, SUMO-PTEN was rapidly excluded from the nucleus dependent on the protein kinase Ataxia telangiectasia mutated (ATM). Cells lacking nuclear PTEN were hypersensitive to DNA damage, while PTEN-deficient cells were susceptible to killing by a combination of genotoxic stress and a small molecule PI3K inhibitor both in vitro and in vivo. Our findings may have implications for individualized therapy for patients with PTEN-deficient tumors. PMID:23888040

  8. Radioprotective effect of Panax ginseng on the phosphatases and lipid peroxidation level in testes of Swiss albino mice

    Energy Technology Data Exchange (ETDEWEB)

    Kumar M.; Sharma M.K.; Saxena P.S.; Kumar A. [Rajasthan Univ., Jaipur (India)

    2003-03-01

    The Panax ginseng has been used as traditional medicine for past several years among oriental people. The present investigation has been made to assess the radioprotective efficacy of ginseng root extract in the testicular enzymes of Swiss albino mice. The Swiss albino mice were divided into different groups. Ginseng treated group: The animals were administered 10 mg/kg body weight ginseng root extract intraperitoneal (i.p.). Radiation treated group: The animals were exposed to 8 Gy gamma radiation at the dose rate of 1.69 Gy/min at the distance of 80 cm. Combination group: Animals were administered ginseng extract continuously for 4 d and on 4th day they were irradiated to 8 Gy gamma radiation after 30 min of extract administration. The animals from above groups were autopsied on day 1, 3, 7, 14 and 30. Biochemical estimations of acid and alkaline phosphatases and Lipid peroxidation (LPO) in testes were done. In ginseng treated group acid and alkaline phosphatases activity and LPO level did not show any significant alteration. In irradiated animals there was a significant increase in acid phosphatase activity and LPO level. However, significant decline in alkaline phosphatase activity was observed. The treatment of ginseng before irradiation causes significant decrease in acid phosphatase and LPO level and significant increase in alkaline phosphatase activity. One of the cause of radiation damage is lipid peroxidation. Due to lipid peroxidation, lysosomal membrane permeability alters and thus results in release of hydrolytic enzymes. So, an increase in acid phosphatase was noticed after radiation treatment. The alkaline phosphatase activity is associated with membrane permeability and different stages of spermatogenesis. Due to membrane damage and depletion of germ cells of testes after irradiation the enzyme activity was decreased. Ginseng markedly inhibits lipid peroxidation. It acts in indirect fashion to protect radical processes by inhibition of initiation of

  9. Discovery and optimization of new benzimidazole- and benzoxazole-pyrimidone selective PI3Kβ inhibitors for the treatment of phosphatase and TENsin homologue (PTEN)-deficient cancers.

    Science.gov (United States)

    Certal, Victor; Halley, Frank; Virone-Oddos, Angela; Delorme, Cécile; Karlsson, Andreas; Rak, Alexey; Thompson, Fabienne; Filoche-Rommé, Bruno; El-Ahmad, Youssef; Carry, Jean-Christophe; Abecassis, Pierre-Yves; Lejeune, Pascale; Vincent, Loic; Bonnevaux, Hélène; Nicolas, Jean-Paul; Bertrand, Thomas; Marquette, Jean-Pierre; Michot, Nadine; Benard, Tsiala; Below, Peter; Vade, Isabelle; Chatreaux, Fabienne; Lebourg, Gilles; Pilorge, Fabienne; Angouillant-Boniface, Odile; Louboutin, Audrey; Lengauer, Christoph; Schio, Laurent

    2012-05-24

    Most of the phosphoinositide-3 kinase (PI3K) kinase inhibitors currently in clinical trials for cancer treatment exhibit pan PI3K isoform profiles. Single PI3K isoforms differentially control tumorigenesis, and PI3Kβ has emerged as the isoform involved in the tumorigenicity of PTEN-deficient tumors. Herein we describe the discovery and optimization of a new series of benzimidazole- and benzoxazole-pyrimidones as small molecular mass PI3Kβ-selective inhibitors. Starting with compound 5 obtained from a one-pot reaction via a novel intermediate 1, medicinal chemistry optimization led to the discovery of compound 8, which showed a significant activity and selectivity for PI3Kβ and adequate in vitro pharmacokinetic properties. The X-ray costructure of compound 8 in PI3Kδ showed key interactions and structural features supporting the observed PI3Kβ isoform selectivity. Compound 8 achieved sustained target modulation and tumor growth delay at well tolerated doses when administered orally to SCID mice implanted with PTEN-deficient human tumor xenografts.

  10. The role of phosphoinositide-3 kinase and PTEN in cardiovascular physiology and disease.

    Science.gov (United States)

    Oudit, Gavin Y; Sun, Hui; Kerfant, Benoit-Gilles; Crackower, Michael A; Penninger, Josef M; Backx, Peter H

    2004-08-01

    Phosphoinositide-3 kinases (PI3Ks) are a family of evolutionary conserved lipid kinases that mediate many cellular responses in both physiologic and pathophysiologic states. Class I PI3K can be activated by either receptor tyrosine kinase (RTK)/cytokine receptor activation (class I(A)) or G-protein-coupled receptors (GPCR) (class I(B)). Once activated PI3Ks generate phosphatidylinositols (PtdIns) (3,4,5)P(3) leading to the recruitment and activation of Akt/protein kinase B (PKB), PDK1 and monomeric G-proteins (e.g. Rac-GTPases), which then activate a range of downstream targets including glycogen synthase kinase-3beta (GSK-3beta), mammalian target of rapamycin (mTOR), p70S6 kinase, endothelial nitric oxide synthase (eNOS) and several anti-apoptotic effectors. Class I(A) (PI3Kalpha, beta and delta) and class I(B) (PI3Kgamma) PI3Ks mediate distinct phenotypes in the heart and under negative control by the 3'-lipid phosphatase, phosphatase and tensin homolog on chromosome ten (PTEN) which dephosphorylate PtdIns(3,4,5)P(3) into PtdIns(4,5)P(2). PI3Kalpha, gamma and PTEN are expressed in cardiomyocytes, fibroblasts, endothelial cells and vascular smooth muscle cells where they modulate cell survival/apoptosis, hypertrophy, contractility, metabolism and mechanotransduction. Several transgenic and knockout models support a fundamental role of PI3K/PTEN signaling in the regulation of myocardial contractility and hypertrophy. Consequently the PI3K/PTEN signaling pathways are involved in a wide variety of diseases including cardiac hypertrophy, heart failure, preconditioning and hypertension. In this review, we discuss the biochemistry and molecular biology of PI3K (class I isoforms) and PTEN and their critical role in cardiovascular physiology and diseases.

  11. A novel PTEN gene promoter mutation and untypical Cowden syndrome

    Institute of Scientific and Technical Information of China (English)

    Chen Liu; Guangbing Li; Rongrong Chen; Xiaobo Yang; Xue Zhao; Haitao Zhao

    2013-01-01

    Cowden syndrome (CS),an autosomal dominant disorder,is one of a spectrum of clinical disorders that have been linked to germline mutations in the phosphatase and tensin homolog (PTEN) gene.Although 70-80% of patients with CS have an identifiable germline PTEN mutation,the clinical diagnosis presents many challenges because of the phenotypic and genotypic variations.In the present study,we sequenced the exons and the promoter of PTEN gene,mutations and variations in the promoter and exons were identified,and a PTEN protein expression negative region was determined by immunohistochemistry (IHC).In conclusion,a novel promoter mutation we found in PTEN gene may turn off PTEN protein expression occasionally,leading to the disorder of PTEN and untypical CS manifestations.

  12. Quantitative and dynamic analysis of PTEN phosphorylation by NMR.

    Science.gov (United States)

    Cordier, Florence; Chaffotte, Alain; Wolff, Nicolas

    2015-05-01

    The dual lipid and protein phosphatase PTEN is a tumor suppressor controlling key biological processes, such as cell growth, proliferation and neuro-survival. Its activity and intracellular trafficking is finely regulated notably by multi-site phosphorylation of its C-terminal tail. The reversible and highly dynamic character of these regulatory events confers a temporal dimension to the cell for triggering crucial decisions. In this review, we describe how a recently developed time-resolved NMR spectroscopy approach unveils the dynamic establishment of the phosphorylation events of PTEN C-terminal tail controlled by CK2 and GSK3β kinases. Two cascades of reactions have been identified, in vitro and in extracts of human neuroblastoma cells. They are triggered independently on two nearby clusters of sites (S380-S385 and S361-S370) and occur on different timescales. In each cascade, the reactions follow an ordered model with a distributive kinetic mechanism. The vision of these cascades as two delay timers activating distinct or time-delayed regulatory responses gives a temporal dimension on PTEN regulation and is discussed in relation to the known functional roles of each cluster. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Tetracyclines increase lipid phosphate phosphatase expression on plasma membranes and turnover of plasma lysophosphatidate.

    Science.gov (United States)

    Tang, Xiaoyun; Zhao, Yuan Y; Dewald, Jay; Curtis, Jonathan M; Brindley, David N

    2016-04-01

    Extracellular lysophosphatidate and sphingosine 1-phosphate (S1P) are important bioactive lipids, which signal through G-protein-coupled receptors to stimulate cell growth and survival. The lysophosphatidate and S1P signals are terminated partly by degradation through three broad-specificity lipid phosphate phosphatases (LPPs) on the cell surface. Significantly, the expression of LPP1 and LPP3 is decreased in many cancers, and this increases the impact of lysophosphatidate and S1P signaling. However, relatively little is known about the physiological or pharmacological regulation of the expression of the different LPPs. We now show that treating several malignant and nonmalignant cell lines with 1 μg/ml tetracycline, doxycycline, or minocycline significantly increased the extracellular degradation of lysophosphatidate. S1P degradation was also increased in cells that expressed high LPP3 activity. These results depended on an increase in the stabilities of the three LPPs and increased expression on the plasma membrane. We tested the physiological significance of these results and showed that treating rats with doxycycline accelerated the clearance of lysophosphatidate, but not S1P, from the circulation. However, administering 100 mg/kg/day doxycycline to mice decreased plasma concentrations of lysophosphatidate and S1P. This study demonstrates a completely new property of tetracyclines in increasing the plasma membrane expression of the LPPs.

  14. The Parvalbumin/Somatostatin Ratio Is Increased in Pten Mutant Mice and by Human PTEN ASD Alleles

    Directory of Open Access Journals (Sweden)

    Daniel Vogt

    2015-05-01

    Full Text Available Mutations in the phosphatase PTEN are strongly implicated in autism spectrum disorder (ASD. Here, we investigate the function of Pten in cortical GABAergic neurons using conditional mutagenesis in mice. Loss of Pten results in a preferential loss of SST+ interneurons, which increases the ratio of parvalbumin/somatostatin (PV/SST interneurons, ectopic PV+ projections in layer I, and inhibition onto glutamatergic cortical neurons. Pten mutant mice exhibit deficits in social behavior and changes in electroencephalogram (EEG power. Using medial ganglionic eminence (MGE transplantation, we test for cell-autonomous functional differences between human PTEN wild-type (WT and ASD alleles. The PTEN ASD alleles are hypomorphic in regulating cell size and the PV/SST ratio in comparison to WT PTEN. This MGE transplantation/complementation assay is efficient and is generally applicable for functional testing of ASD alleles in vivo.

  15. Silymarin induces insulin resistance through an increase of phosphatase and tensin homolog in Wistar rats.

    Directory of Open Access Journals (Sweden)

    Kai-Chun Cheng

    Full Text Available BACKGROUND AND AIMS: Phosphatase and tensin homolog (PTEN is a phosphoinositide phosphatase that regulates crucial cellular functions, including insulin signaling, lipid and glucose metabolism, as well as survival and apoptosis. Silymarin is the active ingredient in milk thistle and exerts numerous effects through the activation of PTEN. However, the effect of silymarin on the development of insulin resistance remains unknown. METHODS: Wistar rats fed fructose-rich chow or normal chow were administered oral silymarin to identify the development of insulin resistance using the homeostasis model assessment of insulin resistance and hyperinsulinemic- euglycemic clamping. Changes in PTEN expression in skeletal muscle and liver were compared using western blotting analysis. Further investigation was performed in L6 cells to check the expression of PTEN and insulin-related signals. PTEN deletion in L6 cells was achieved by small interfering ribonucleic acid transfection. RESULTS: Oral administration of silymarin at a dose of 200 mg/kg once daily induced insulin resistance in normal rats and enhanced insulin resistance in fructose-rich chow-fed rats. An increase of PTEN expression was observed in the skeletal muscle and liver of rats with insulin resistance. A decrease in the phosphorylation of Akt in L6 myotube cells, which was maintained in a high-glucose condition, was also observed. Treatment with silymarin aggravated high-glucose-induced insulin resistance. Deletion of PTEN in L6 cells reversed silymarin-induced impaired insulin signaling and glucose uptake. CONCLUSIONS: Silymarin has the ability to disrupt insulin signaling through increased PTEN expression. Therefore, silymarin should be used carefully in type-2 diabetic patients.

  16. A unified nomenclature and amino acid numbering for human PTEN

    NARCIS (Netherlands)

    Pulido, Rafael; Baker, Suzanne J; Barata, Joao T; Carracedo, Arkaitz; Cid, Victor J; Chin-Sang, Ian D; Davé, Vrushank; den Hertog, Jeroen; Devreotes, Peter; Eickholt, Britta J; Eng, Charis; Furnari, Frank B; Georgescu, Maria-Magdalena; Gericke, Arne; Hopkins, Benjamin; Jiang, Xeujun; Lee, Seung-Rock; Lösche, Mathias; Malaney, Prerna; Matias-Guiu, Xavier; Molina, María; Pandolfi, Pier Paolo; Parsons, Ramon; Pinton, Paolo; Rivas, Carmen; Rocha, Rafael M; Rodríguez, Manuel S; Ross, Alonzo H; Serrano, Manuel; Stambolic, Vuk; Stiles, Bangyan; Suzuki, Akira; Tan, Seong-Seng; Tonks, Nicholas K; Trotman, Lloyd C; Wolff, Nicolas; Woscholski, Rudiger; Wu, Hong; Leslie, Nicholas R

    2014-01-01

    The tumor suppressor PTEN is a major brake for cell transformation, mainly due to its phosphatidylinositol 3,4,5-trisphosphate [PI(3,4,5)P3] phosphatase activity that directly counteracts the oncogenicity of phosphoinositide 3-kinase (PI3K). PTEN mutations are frequent in tumors and in the germ line

  17. A unified nomenclature and amino acid numbering for human PTEN

    NARCIS (Netherlands)

    Pulido, Rafael; Baker, Suzanne J; Barata, Joao T; Carracedo, Arkaitz; Cid, Victor J; Chin-Sang, Ian D; Davé, Vrushank; den Hertog, Jeroen; Devreotes, Peter; Eickholt, Britta J; Eng, Charis; Furnari, Frank B; Georgescu, Maria-Magdalena; Gericke, Arne; Hopkins, Benjamin; Jiang, Xeujun; Lee, Seung-Rock; Lösche, Mathias; Malaney, Prerna; Matias-Guiu, Xavier; Molina, María; Pandolfi, Pier Paolo; Parsons, Ramon; Pinton, Paolo; Rivas, Carmen; Rocha, Rafael M; Rodríguez, Manuel S; Ross, Alonzo H; Serrano, Manuel; Stambolic, Vuk; Stiles, Bangyan; Suzuki, Akira; Tan, Seong-Seng; Tonks, Nicholas K; Trotman, Lloyd C; Wolff, Nicolas; Woscholski, Rudiger; Wu, Hong; Leslie, Nicholas R

    2014-01-01

    The tumor suppressor PTEN is a major brake for cell transformation, mainly due to its phosphatidylinositol 3,4,5-trisphosphate [PI(3,4,5)P3] phosphatase activity that directly counteracts the oncogenicity of phosphoinositide 3-kinase (PI3K). PTEN mutations are frequent in tumors and in the germ line

  18. Phosphatase and Tensin Homolog Is a Growth Repressor of Both Rhizoid and Gametophore Development in the Moss Physcomitrella patens.

    Science.gov (United States)

    Saavedra, Laura; Catarino, Rita; Heinz, Tobias; Heilmann, Ingo; Bezanilla, Magdalena; Malhó, Rui

    2015-12-01

    Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a lipid phosphatase implicated in cellular proliferation and survival. In animal cells, loss of PTEN leads to increased levels of phosphatidylinositol (3,4,5)-trisphosphate, stimulation of glucose and lipid metabolism, cellular growth, and morphological changes (related to adaptation and survival). Intriguingly, in plants, phosphatidylinositol (3,4,5)-trisphosphate has not been detected, and the enzymes that synthesize it were never reported. In this study we performed a genetic, biochemical, and functional characterization of the moss Physcomitrella patens PTEN gene family. P. patens has four PTENs, which are ubiquitously expressed during the entire moss life cycle. Using a knock-in approach, we show that all four genes are expressed in growing tissues, namely caulonemal and rhizoid cells. At the subcellular level, PpPTEN-green fluorescent protein fusions localized to the cytosol and the nucleus. Analysis of single and double knockouts revealed no significant phenotypes at different developmental stages, indicative of functional redundancy. However, compared with wild-type triple and quadruple pten knockouts, caulonemal cells grew faster, switched from the juvenile protonemal stage to adult gametophores earlier, and produced more rhizoids. Furthermore, analysis of lipid content and quantitative real-time polymerase chain reaction data performed in quadruple mutants revealed altered phosphoinositide levels [increase in phosphatidylinositol (3,5)-bisphosphate and decrease in phosphatidylinositol 3-phosphate] and up-regulation of marker genes from the synthesis phase of the cell cycle (e.g. P. patens proliferating cell nuclear antigen, ribonucleotide reductase, and minichromosome maintenance) and of the retinoblastoma-related protein gene P. patens retinoblastoma-related protein1. Together, these results suggest that PpPTEN is a suppressor of cell growth and morphogenic development in plants.

  19. Binding of PTEN to specific PDZ domains contributes to PTEN protein stability and phosphorylation by microtubule-associated serine/threonine kinases.

    Science.gov (United States)

    Valiente, Miguel; Andrés-Pons, Amparo; Gomar, Beatriz; Torres, Josema; Gil, Anabel; Tapparel, Caroline; Antonarakis, Stylianos E; Pulido, Rafael

    2005-08-12

    The tumor suppressor phosphatase PTEN is a key regulator of cell growth and apoptosis that interacts with PDZ domains from regulatory proteins, including MAGI-1/2/3, hDlg, and MAST205. Here we identified novel PTEN-binding PDZ domains within the MAST205-related proteins, syntrophin-associated serine/threonine kinase and MAST3, characterized the regions of PTEN involved in its interaction with distinctive PDZ domains, and analyzed the functional consequences on PTEN of PDZ domain binding. Using a panel of PTEN mutations, as well as PTEN chimeras containing distinct domains of the related protein TPTE, we found that the PTP and C2 domains of PTEN do not affect PDZ domain binding and that the C-terminal tail of PTEN (residues 350-403) provides selectivity to recognize specific PDZ domains from MAGI-2, hDlg, and MAST205. Binding of PTEN to the PDZ-2 domain from MAGI-2 increased PTEN protein stability. Furthermore, binding of PTEN to the PDZ domains from microtubule-associated serine/threonine kinases facilitated PTEN phosphorylation at its C terminus by these kinases. Our results suggest an important role for the C-terminal region of PTEN in the selective association with scaffolding and/or regulatory molecules and provide evidence that PDZ domain binding stabilizes PTEN and targets this tumor suppressor for phosphorylation by microtubule-associated serine/threonine kinases.

  20. Structural Insight into Substrate Selection and Catalysis of Lipid Phosphate Phosphatase PgpB in the Cell Membrane.

    Science.gov (United States)

    Tong, Shuilong; Lin, Yibin; Lu, Shuo; Wang, Meitian; Bogdanov, Mikhail; Zheng, Lei

    2016-08-26

    PgpB belongs to the lipid phosphate phosphatase protein family and is one of three bacterial integral membrane phosphatases catalyzing dephosphorylation of phosphatidylglycerol phosphate (PGP) to generate phosphatidylglycerol. Although the structure of its apo form became recently available, the mechanisms of PgpB substrate binding and catalysis are still unclear. We found that PgpB was inhibited by phosphatidylethanolamine (PE) in a competitive mode in vitro Here we report the crystal structure of the lipid-bound form of PgpB. The structure shows that a PE molecule is stabilized in a membrane-embedded tunnel formed by TM3 and the "PSGH" fingerprint peptide near the catalytic site, providing structural insight into PgpB substrate binding mechanism. Noteworthy, in silico docking of varied lipid phosphates exhibited similar substrate binding modes to that of PE, and the residues in the lipid tunnel appear to be important for PgpB catalysis. The catalytic triad in the active site is essential for dephosphorylating substrates lysophosphatidic acid, phosphatidic acid, or sphingosine-1-phosphate but surprisingly not for the native substrate PGP. Remarkably, residue His-207 alone is sufficient to hydrolyze PGP, indicating a specific catalytic mechanism for PgpB in PG biosynthesis. We also identified two novel sensor residues, Lys-93 and Lys-97, on TM3. Our data show that Lys-97 is essential for the recognition of lyso-form substrates. Modification at the Lys-93 position may alter substrate specificity of lipid phosphate phosphatase proteins in prokaryotes versus eukaryotes. These studies reveal new mechanisms of lipid substrate selection and catalysis by PgpB and suggest that the enzyme rests in a PE-stabilized state in the bilayer. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  1. Structural Insight into Substrate Selection and Catalysis of Lipid Phosphate Phosphatase PgpB in the Cell Membrane*

    Science.gov (United States)

    Tong, Shuilong; Lin, Yibin; Lu, Shuo; Wang, Meitian; Bogdanov, Mikhail; Zheng, Lei

    2016-01-01

    PgpB belongs to the lipid phosphate phosphatase protein family and is one of three bacterial integral membrane phosphatases catalyzing dephosphorylation of phosphatidylglycerol phosphate (PGP) to generate phosphatidylglycerol. Although the structure of its apo form became recently available, the mechanisms of PgpB substrate binding and catalysis are still unclear. We found that PgpB was inhibited by phosphatidylethanolamine (PE) in a competitive mode in vitro. Here we report the crystal structure of the lipid-bound form of PgpB. The structure shows that a PE molecule is stabilized in a membrane-embedded tunnel formed by TM3 and the “PSGH” fingerprint peptide near the catalytic site, providing structural insight into PgpB substrate binding mechanism. Noteworthy, in silico docking of varied lipid phosphates exhibited similar substrate binding modes to that of PE, and the residues in the lipid tunnel appear to be important for PgpB catalysis. The catalytic triad in the active site is essential for dephosphorylating substrates lysophosphatidic acid, phosphatidic acid, or sphingosine-1-phosphate but surprisingly not for the native substrate PGP. Remarkably, residue His-207 alone is sufficient to hydrolyze PGP, indicating a specific catalytic mechanism for PgpB in PG biosynthesis. We also identified two novel sensor residues, Lys-93 and Lys-97, on TM3. Our data show that Lys-97 is essential for the recognition of lyso-form substrates. Modification at the Lys-93 position may alter substrate specificity of lipid phosphate phosphatase proteins in prokaryotes versus eukaryotes. These studies reveal new mechanisms of lipid substrate selection and catalysis by PgpB and suggest that the enzyme rests in a PE-stabilized state in the bilayer. PMID:27405756

  2. Von Hippel-Lindau status influences phenotype of liver cancers arising from PTEN loss

    Directory of Open Access Journals (Sweden)

    Sendor AB

    2015-02-01

    aggressive tumor formation and widespread steatosis in mouse livers. Co-deletion of Vhl and Pten results in lower tumor burden with gene expression profiling suggesting a switch from a profile of lipid deposition to an expression profile more consistent with upregulation of the hypoxia response pathway. A relationship between tumor hypoxia signaling and altered hepatic steatotic response suggests that competing influences may alter tumor phenotypes.Keywords: Von Hippel-Lindau (VHL, phosphatase and tension homologue deleted on chromosome 10 (PTEN, cholangiocarcinoma (CC, hepatocellular-cholangiocarcinoma (HCC

  3. PTEN sequence analysis in endometrial hyperplasia and endometrial carcinoma in Slovak women.

    Science.gov (United States)

    Gbelcová, H; Bakeš, P; Priščáková, P; Šišovský, V; Hojsíková, I; Straka, Ľ; Konečný, M; Markus, J; D'Acunto, C W; Ruml, T; Böhmer, D; Danihel, Ľ; Repiská, V

    2015-01-01

    Phosphatase and tensin homolog (PTEN) is a protein that acts as a tumor suppressor by dephosphorylating the lipid second messenger phosphatidylinositol 3,4,5-trisphosphate. Loss of PTEN function has been implicated in the pathogenesis of a number of different tumors, particularly endometrial carcinoma (ECa). ECa is the most common neoplasia of the female genital tract. Our study evaluates an association between the morphological appearance of endometrial hyperplasia and endometrial carcinoma and the degree of PTEN alterations. A total of 45 endometrial biopsies from Slovak women were included in present study. Formalin-fixed and paraffin-embedded tissue samples with simple hyperplasia (3), complex hyperplasia (5), atypical complex hyperplasia (7), endometrioid carcinomas G1 (20) and G3 (5), and serous carcinoma (5) were evaluated for the presence of mutations in coding regions of PTEN gene, the most frequently mutated tumor suppressor gene in endometrial carcinoma. 75% of the detected mutations were clustered in exons 5 and 8. Out of the 39 mutations detected in 24 cases, 20 were frameshifts and 19 were nonsense, missense, or silent mutations. Some specimens harboured more than one mutation. The results of current study on Slovak women were compared to a previous study performed on Polish population. The two sets of results were similar.

  4. PTEN Sequence Analysis in Endometrial Hyperplasia and Endometrial Carcinoma in Slovak Women

    Directory of Open Access Journals (Sweden)

    H. Gbelcová

    2015-01-01

    Full Text Available Phosphatase and tensin homolog (PTEN is a protein that acts as a tumor suppressor by dephosphorylating the lipid second messenger phosphatidylinositol 3,4,5-trisphosphate. Loss of PTEN function has been implicated in the pathogenesis of a number of different tumors, particularly endometrial carcinoma (ECa. ECa is the most common neoplasia of the female genital tract. Our study evaluates an association between the morphological appearance of endometrial hyperplasia and endometrial carcinoma and the degree of PTEN alterations. A total of 45 endometrial biopsies from Slovak women were included in present study. Formalin-fixed and paraffin-embedded tissue samples with simple hyperplasia (3, complex hyperplasia (5, atypical complex hyperplasia (7, endometrioid carcinomas G1 (20 and G3 (5, and serous carcinoma (5 were evaluated for the presence of mutations in coding regions of PTEN gene, the most frequently mutated tumor suppressor gene in endometrial carcinoma. 75% of the detected mutations were clustered in exons 5 and 8. Out of the 39 mutations detected in 24 cases, 20 were frameshifts and 19 were nonsense, missense, or silent mutations. Some specimens harboured more than one mutation. The results of current study on Slovak women were compared to a previous study performed on Polish population. The two sets of results were similar.

  5. Phosphorylation of PTEN at STT motif is associated with DNA damage response

    Energy Technology Data Exchange (ETDEWEB)

    Misra, Sandip; Mukherjee, Ananda; Karmakar, Parimal, E-mail: pkarmakar_28@yahoo.co.in

    2014-12-15

    Highlights: • Phosphorylation PTEN at the C-terminal STT motif is necessary for DNA repair. • DNA damage induces phosphorylation of STT motif of PTEN. • Phospho-PTEN translocates to nucleus after DNA damage. • Phospho-PTEN forms nuclear foci after DNA damage which co localized with γH2AX. - Abstract: Phosphatase and tensin homolog deleted on chromosome Ten (PTEN), a tumor suppressor protein participates in multiple cellular activities including DNA repair. In this work we found a relationship between phosphorylation of carboxy (C)-terminal STT motif of PTEN and DNA damage response. Ectopic expression of C-terminal phospho-mutants of PTEN, in PTEN deficient human glioblastoma cells, U87MG, resulted in reduced viability and DNA repair after etoposide induced DNA damage compared to cells expressing wild type PTEN. Also, after etoposide treatment phosphorylation of PTEN increased at C-terminal serine 380 and threonine 382/383 residues in PTEN positive HEK293T cells and wild type PTEN transfected U87MG cells. One-step further, DNA damage induced phosphorylation of PTEN was confirmed by immunoprecipitation of total PTEN from cellular extract followed by immunobloting with phospho-specific PTEN antibodies. Additionally, phospho-PTEN translocated to nucleus after etoposide treatment as revealed by indirect immunolabeling. Further, phosphorylation dependent nuclear foci formation of PTEN was observed after ionizing radiation or etoposide treatment which colocalized with γH2AX. Additionally, etoposide induced γH2AX, Mre11 and Ku70 foci persisted for a longer period of times in U87MG cells after ectopic expression of PTEN C-terminal phospho-mutant constructs compared to wild type PTEN expressing cells. Thus, our findings strongly suggest that DNA damage induced phosphorylation of C-terminal STT motif of PTEN is necessary for DNA repair.

  6. PTEN status in advanced colorectal cancer treated with cetuximab

    Science.gov (United States)

    Negri, F V; Bozzetti, C; Lagrasta, C A; Crafa, P; Bonasoni, M P; Camisa, R; Pedrazzi, G; Ardizzoni, A

    2009-01-01

    Background: Loss of phosphatase and tensin homologue deleted in chromosome 10 (PTEN) function in advanced colorectal cancer (CRC) may represent one of the resistance mechanisms to cetuximab by interfering with the epidermal growth factor receptor signal transduction pathway. Methods: PTEN expression tested by indirect immunofluorescence was evaluated both on primary (n=43) and on metastatic (n=24) sites in CRC patients treated with cetuximab. Results: The loss of PTEN expression tested on metastatic sites was negatively associated with response (100% progressive disease (PD) in PTEN-negative cases vs 30% PD in PTEN-positive cases; P<0.05), PFS (0.8 vs 8.2 months; P<0.001) and OS (2.9 vs 14.2 months; P<0.001). Conclusion: A potential role of PTEN in the anti-tumour activity of cetuximab could be hypothesised. PMID:19953097

  7. The role of alkaline phosphatase in intracellular lipid accumulation in the human hepatocarcinoma cell line, HepG2.

    Science.gov (United States)

    Chirambo, George M; van Niekerk, Chantal; Crowther, Nigel J

    2017-04-01

    Inhibition of tissue non-specific alkaline phosphatase (TNALP) decreases intracellular lipid accumulation in human preadipocytes and the murine preadipocyte cell line, 3T3-L1. Therefore, the current study was performed to determine if TNALP is required for intracellular lipid deposition in the human hepatocyte cell line, HepG2. Intracellular lipid accumulation, TNALP activity and peroxisome proliferator activated receptor (PPAR) γ gene expression were measured in HepG2 and 3T3-L1 cells in the presence and absence of the TNALP inhibitors levamisole and histidine. Sub-cellular TNALP activity was localized using cytochemical analysis. Both PPARγ gene expression and TNALP activity increased during intracellular lipid accumulation in HepG2 and 3T3-L1 cells. Inhibition of TNALP blocked intracellular lipid accumulation but did not alter expression of the PPARγ gene. In HepG2 cells, TNALP co-localized with adipophilin on the lipid droplet membrane. These data suggest a role for TNALP in lipid droplet formation, possibly downstream from PPARγ, within HepG2 and 3T3-L1 cells. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Effects of mir-21 on Cardiac Microvascular Endothelial Cells After Acute Myocardial Infarction in Rats: Role of Phosphatase and Tensin Homolog (PTEN)/Vascular Endothelial Growth Factor (VEGF) Signal Pathway

    Science.gov (United States)

    Yang, Feng; Liu, Wenwei; Yan, Xiaojuan; Zhou, Hanyun; Zhang, Hongshen; Liu, Jianfei; Yu, Ming; Zhu, Xiaoshan; Ma, Kezhong

    2016-01-01

    Background This study investigated how miR-21 expression is reflected in acute myocardial infarction and explored the role of miR-21 and the PTEN/VEGF signaling pathway in cardiac microvascular endothelial cells. Material/Methods We used an in vivo LAD rat model to simulate acute myocardial infarction. MiR-21 mimics and miR-21 inhibitors were injected and transfected into model rats in order to alter miR-21 expression. Cardiac functions were evaluated using echocardiographic measurement, ELISA, and Masson staining. In addition, lenti-PTEN and VEGF siRNA were transfected into CMEC cells using standard procedures for assessing the effect of PTEN and VEGE on cell proliferation, apoptosis, and angiogenesis. MiR-21, PTEN, and VEGF expressions were examined by RT-PCR and Western blot. The relationship between miR-21 and PTEN was determined by the luciferase activity assay. Results We demonstrated that miR-21 bonded with the 3′-UTR of PTEN and suppressed PTEN expressions. Established models significantly induced cardiac infarct volume and endothelial injury marker expressions as well as miR-21 and PTEN expressions (PMiR-21 mimics exhibited significantly protective effects since they down-regulated both infarction size and injury marker expressions by increasing VEGF expression and inhibiting PTEN expression (PmiR-21 on cell proliferation, apoptosis, and angiogenesis (PMiR-21 exerts protective effects on endothelial injury through the PTEN/VEGF pathway after acute myocardial infarction. PMID:27708252

  9. [Inhibitory effects of tumor suppressor gene PTEN on proliferation and metastasis of breast cancer ZR-75-1 cells].

    Science.gov (United States)

    Lin, Guan-Ping; Li, Xiang-Yong; Huang, Jin-Wen; Xiong, Liang; Zhou, Ke-Yuan

    2007-10-01

    Tumor suppressor gene PTEN could not only inhibit the proliferation of cancer cells, but also inhibit their metastasis. However, the mechanism is still unclear. This study was to investigate the effects of PTEN gene on the proliferation and metastasis of human breast cancer ZR-75-1 cells, and explore the mechanisms. Wild-type PTEN (wt-PTEN) plasmid and phosphatase-defective PTEN (G129R-PTEN) plasmid were transfected into ZR-75-1 cells by liposome, respectively. Cell proliferation was detected by MTT assay. Transfected cells were selected by puromycin. The expression of PTEN protein was detected by Western blot. Cell adhesion and invasion were tested by adhesion test and invasion test. The proliferation inhibition rate was significantly higher in wt-PTEN-transfected ZR-75-1 cells than in untransfected cells and G129R-PTEN-transfected cells (42.7% vs. 0% and 2.7%, P0.05). The proliferation inhibition of ZR-75-1 cells was enhanced along with the increase of culture time and concentration of wt-PTEN. wt-PTEN also induced cell apoptosis. PTEN protein was expressed efficiently in the cells transfected with either wt-PTEN or G129R-PTEN. The inhibition rates of adhesion and invasion were significantly higher in wt-PTEN-transfected cells than in G129R-PTEN-transfected cells (65.7% vs. 8.8%, 70.4% vs. 6.9%, PZR-75-1 cells.

  10. LptO (PG0027) Is Required for Lipid A 1-Phosphatase Activity in Porphyromonas gingivalis W50.

    Science.gov (United States)

    Rangarajan, Minnie; Aduse-Opoku, Joseph; Hashim, Ahmed; McPhail, Graham; Luklinska, Zofia; Haurat, M Florencia; Feldman, Mario F; Curtis, Michael A

    2017-06-01

    Porphyromonas gingivalis produces outer membrane vesicles (OMVs) rich in virulence factors, including cysteine proteases and A-LPS, one of the two lipopolysaccharides (LPSs) produced by this organism. Previous studies had suggested that A-LPS and PG0027, an outer membrane (OM) protein, may be involved in OMV formation. Their roles in this process were examined by using W50 parent and the ΔPG0027 mutant strains. Inactivation of PG0027 caused a reduction in the yield of OMVs. Lipid A from cells and OMVs of P. gingivalis W50 and the ΔPG0027 mutant strains were analyzed by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Lipid A from W50 cells contained bis-P-pentaacyl, mono-P-pentaacyl, mono-P-tetraacyl, non-P-pentaacyl, and non-P-tetraacyl species, whereas lipid A from ΔPG0027 mutant cells contained only phosphorylated species; nonphosphorylated species were absent. MALDI-TOF/TOF tandem MS of mono-P-pentaacyl (m/z 1,688) and mono-P-tetraacyl (m/z 1,448) lipid A from ΔPG0027 showed that both contained lipid A 1-phosphate, suggesting that the ΔPG0027 mutant strain lacked lipid A 1-phosphatase activity. The total phosphatase activities in the W50 and the ΔPG0027 mutant strains were similar, whereas the phosphatase activity in the periplasm of the ΔPG0027 mutant was lower than that in W50, supporting a role for PG0027 in lipid A dephosphorylation. W50 OMVs were enriched in A-LPS, and its lipid A did not contain nonphosphorylated species, whereas lipid A from the ΔPG0027 mutant (OMVs and cells) contained similar species. Thus, OMVs in P. gingivalis are apparently formed in regions of the OM enriched in A-LPS devoid of nonphosphorylated lipid A. Conversely, dephosphorylation of lipid A through a PG0027-dependent process is required for optimal formation of OMVs. Hence, the relative proportions of nonphosphorylated and phosphorylated lipid A appear to be crucial for OMV formation in this organism.IMPORTANCE Gram

  11. PTEN Gene: A Model for Genetic Diseases in Dermatology

    Directory of Open Access Journals (Sweden)

    Corrado Romano

    2012-01-01

    Full Text Available PTEN gene is considered one of the most mutated tumor suppressor genes in human cancer, and it’s likely to become the first one in the near future. Since 1997, its involvement in tumor suppression has smoothly increased, up to the current importance. Germline mutations of PTEN cause the PTEN hamartoma tumor syndrome (PHTS, which include the past-called Cowden, Bannayan-Riley-Ruvalcaba, Proteus, Proteus-like, and Lhermitte-Duclos syndromes. Somatic mutations of PTEN have been observed in glioblastoma, prostate cancer, and brest cancer cell lines, quoting only the first tissues where the involvement has been proven. The negative regulation of cell interactions with the extracellular matrix could be the way PTEN phosphatase acts as a tumor suppressor. PTEN gene plays an essential role in human development. A recent model sees PTEN function as a stepwise gradation, which can be impaired not only by heterozygous mutations and homozygous losses, but also by other molecular mechanisms, such as transcriptional regression, epigenetic silencing, regulation by microRNAs, posttranslational modification, and aberrant localization. The involvement of PTEN function in melanoma and multistage skin carcinogenesis, with its implication in cancer treatment, and the role of front office in diagnosing PHTS are the main reasons why the dermatologist should know about PTEN.

  12. A new pathway of glucocorticoid action for asthma treatment through the regulation of PTEN expression

    Directory of Open Access Journals (Sweden)

    Chen Qingge

    2011-04-01

    Full Text Available Abstract Background "Phosphatase and tensin homolog deleted on chromosome 10" (PTEN is mostly considered to be a cancer-related gene, and has been suggested to be a new pathway of pathogenesis of asthma. The purpose of this study was to investigate the effects of the glucocorticoid, dexamethasone, on PTEN regulation. Methods OVA-challenged mice were used as an asthma model to investigate the effect of dexamethasone on PTEN regulation. Immunohistochemistry was used to detect expression levels of PTEN protein in lung tissues. The human A549 cell line was used to explore the possible mechanism of action of dexamethasone on human PTEN regulation in vitro. A luciferase reporter construct under the control of PTEN promoter was used to confirm transcriptional regulation in response to dexamethasone. Results PTEN protein was found to be expressed at low levels in lung tissues in asthmatic mice; but the expression was restored after treatment with dexamethasone. In A549 cells, human PTEN was up-regulated by dexamethasone treatment. The promoter-reporter construct confirmed that dexamethasone could regulate human PTEN transcription. Treatment with the histone deacetylase inhibitor, TSA, could increase PTEN expression in A549 cells, while inhibition of histone acetylase (HAT by anacardic acid attenuated dexamethasone-induced PTEN expression. Conclusions Based on the data a new mechanism is proposed where glucocorticoids treat asthma partly through up-regulation of PTEN expression. The in vitro studies also suggest that the PTEN pathway may be involved in human asthma.

  13. Activation of phosphatase and tensin homolog on chromosome 10 mediates the inhibition of FcgammaR phagocytosis by prostaglandin E2 in alveolar macrophages.

    Science.gov (United States)

    Canetti, Claudio; Serezani, Carlos H; Atrasz, Rachelle G; White, Eric S; Aronoff, David M; Peters-Golden, Marc

    2007-12-15

    PGE2 has important inhibitory effects on the macrophage host defense functions of phagocytosis and killing, yet the molecular mechanisms involved remain to be fully elucidated. PGE2 causes an elevation of cAMP in alveolar macrophages (AMs), which in turn activates the cAMP effector targets, protein kinase A and the exchange protein activated by cAMP (Epac)-1. We now report that FcgammaR-induced PI3K/Akt and ERK-1/2 activation are inhibited by PGE2 in AMs. By specifically inhibiting the phosphatase and tensin homolog deleted on chromosome 10 (PTEN) in AMs, we attenuated the inhibitory effects of both PGE2 and a specific Epac-1 agonist (8-pCPT-2'-O-Me-cAMP) on FcgammaR-mediated phagocytosis and Akt/ERK-1/2 activation; PTEN inhibition also decreased PGE2-induced suppression of bacterial killing by AMs. Moreover, PGE2 and the Epac-1 agonist induced an increase in PTEN lipid phosphatase activity, and this was associated with decreased tyrosine phosphorylation on PTEN-a mechanism known to regulate PTEN activity. Using a pharmacological approach, we demonstrated a role for Src homology 2-containing protein tyrosine phosphatase-1 in the PGE2-induced tyrosine dephosphorylation of PTEN. Collectively, these data reveal that PGE2, via Epac-1 activation, enhances SHP-1 activity, resulting in increased PTEN activity. We suggest that this mechanism contributes to the ability of PGE2 to inhibit PI3K-dependent innate immune signaling in primary macrophages.

  14. Caffeine activates tumor suppressor PTEN in sarcoma cells

    OpenAIRE

    Miwa, Shinji; Sugimoto, Naotoshi; Shirai, Toshiharu; Hayashi, Katsuhiro; Nishida, Hideji; Ohnari, Issei; Takeuchi, Akihiko; Yachie, Akihiro; Tsuchiya, Hiroyuki

    2011-01-01

    The tumor suppressor phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a negative regulator of the phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway. Akt activation exerts a strong anti-apoptotic effect and inhibits key pro-apoptotic proteins. We investigated the effect of caffeine in the prevention of tumor cell proliferation and induction of cell death. We found that caffeine induced increased intracellular cAMP levels, PTEN activation and Akt inactivation, which to...

  15. A novel role for PTEN in the inhibition of neurite outgrowth by Myelin-associated glycoprotein in cortical neurons

    Science.gov (United States)

    Perdigoto, Ana Luisa; Chaudhry, Nagarathnamma; Barnes, Gregory N.; Filbin, Marie T.; Carter, Bruce D.

    2010-01-01

    Axonal regeneration in the central nervous system is prevented, in part, by inhibitory proteins expressed by myelin, including Myelin-associated glycoprotein (MAG). Although injury to the corticospinal tract can result in permanent disability, little is known regarding the mechanisms by which MAG affects cortical neurons. Here, we demonstrate that cortical neurons plated on MAG expressing CHO cells, exhibit a striking reduction in process outgrowth. Interestingly, none of the receptors previously implicated in MAG signaling, including the p75 neurotrophin receptor or gangliosides, contributed significantly to MAG-mediated inhibition. However, blocking the small GTPase Rho or its downstream effector kinase, ROCK, partially reversed the effects of MAG on the neurons. In addition, we identified the lipid phosphatase PTEN as a mediator of MAG’s inhibitory effects on neurite outgrowth. Knockdown or gene deletion of PTEN or over expression of activated AKT in cortical neurons resulted in significant, although partial, rescue of neurite outgrowth on MAG-CHO cells. Moreover, MAG decreased the levels of phospho-Akt, suggesting that it activates PTEN in the neurons. Taken together, these results suggest a novel pathway activated by MAG in cortical neurons involving the PTEN/PI3K/AKT axis. PMID:20869442

  16. PTEN functions to 'prioritize' chemotactic cues and prevent 'distraction' in migrating neutrophils.

    Science.gov (United States)

    Heit, Bryan; Robbins, Stephen M; Downey, Charlene M; Guan, Zhiwen; Colarusso, Pina; Miller, B Joan; Jirik, Frank R; Kubes, Paul

    2008-07-01

    Neutrophils encounter and 'prioritize' many chemoattractants in their pursuit of bacteria. Here we tested the possibility that the phosphatase PTEN is responsible for the prioritization of chemoattractants. Neutrophils induced chemotaxis by two separate pathways, the phosphatidylinositol-3-OH kinase (PI(3)K) phosphatase and tensin homolog (PTEN) pathway, and the p38 mitogen-activated protein kinase pathway, with the p38 pathway dominating over the PI(3)K pathway. Pten(-/-) neutrophils could not prioritize chemoattractants and were 'distracted' by chemokines when moving toward bacterial chemoattractants. In opposing gradients, PTEN became distributed throughout the cell circumference, which inhibited all PI(3)K activity, thus permitting 'preferential' migration toward bacterial products via phospholipase A(2) and p38. Such prioritization was defective in Pten(-/-) neutrophils, which resulted in defective bacterial clearance in vivo. Our data identify a PTEN-dependent mechanism in neutrophils to prioritize, 'triage' and integrate responses to multiple chemotactic cues.

  17. High-resolution Structures of Protein-Membrane Complexes by Neutron Reflection and MD Simulation: Membrane Association of the PTEN Tumor Suppressor

    Science.gov (United States)

    Lösche, Matthias

    2012-02-01

    The lipid matrix of biomembranes is an in-plane fluid, thermally and compositionally disordered leaflet of 5 nm thickness and notoriously difficult to characterize in structural terms. Yet, biomembranes are ubiquitous in the cell, and membrane-bound proteins are implicated in a variety of signaling pathways and intra-cellular transport. We developed methodology to study proteins associated with model membranes using neutron reflection measurements and showed recently that this approach can resolve the penetration depth and orientation of membrane proteins with ångstrom resolution if their crystal or NMR structure is known. Here we apply this technology to determine the membrane bindung and unravel functional details of the PTEN phosphatase, a key player in the PI3K apoptosis pathway. PTEN is an important regulatory protein and tumor suppressor that performs its phosphatase activity as an interfacial enzyme at the plasma membrane-cytoplasm boundary. Acting as an antagonist to phosphoinositide-3-kinase (PI3K) in cell signaling, it is deleted in many human cancers. Despite its importance in regulating the levels of the phosphoinositoltriphosphate PI(3,4,5)P3, there is little understanding of how PTEN binds to membranes, is activated and then acts as a phosphatase. We investigated the structure and function of PTEN by studying its membrane affinity and localization on in-plane fluid, thermally disordered synthetic membrane models. The membrane association of the protein depends strongly on membrane composition, where phosphatidylserine (PS) and phosphatidylinositol diphosphate (PI(4,5)P2) act synergetically in attracting the enzyme to the membrane surface. Membrane affinities depend strongly on membrane fluidity, which suggests multiple binding sites on the protein for PI(4,5)P2. Neutron reflection measurements show that the PTEN phosphatase ``scoots'' along the membrane surface (penetration protein, ˜ 60 å away from the bilayer surface, in a rather compact

  18. A Novel PTEN/Mutant p53/c-Myc/Bcl-XL Axis Mediates Context-Dependent Oncogenic Effects of PTEN with Implications for Cancer Prognosis and Therapy

    Directory of Open Access Journals (Sweden)

    Xiaoping Huang

    2013-08-01

    Full Text Available Phosphatase and tensin homolog located on chromosome 10 (PTEN is one of the most frequently mutated tumor suppressors in human cancer including in glioblastoma. Here, we show that PTEN exerts unconventional oncogenic effects in glioblastoma through a novel PTEN/mutant p53/c-Myc/Bcl-XL molecular and functional axis. Using a wide array of molecular, genetic, and functional approaches, we demonstrate that PTEN enhances a transcriptional complex containing gain-of-function mutant p53, CBP, and NFY in human glioblastoma cells and tumor tissues. The mutant p53/CBP/NFY complex transcriptionally activates the oncogenes c-Myc and Bcl-XL, leading to increased cell proliferation, survival, invasion, and clonogenicity. Disruption of the mutant p53/c-Myc/Bcl-XL axis or mutant p53/CBP/NFY complex reverses the transcriptional and oncogenic effects of PTEN and unmasks its tumor-suppressive function. Consistent with these data, we find that PTEN expression is associated with worse patient survival than PTEN loss in tumors harboring mutant p53 and that a small molecule modulator of p53 exerts greater antitumor effects in PTEN-expressing cancer cells. Altogether, our study describes a new signaling pathway that mediates context-dependent oncogenic/tumor-suppressive role of PTEN. The data also indicate that the combined mutational status of PTEN and p53 influences cancer prognosis and anticancer therapies that target PTEN and p53.

  19. Suppression of gastric cancer growth by adenovirus-mediated transfer of the PTEN gene

    Institute of Scientific and Technical Information of China (English)

    Ying Hang; Yong-Chen Zheng; Yan Cao; Qing-Shan Li; Yu-Jie Sui

    2005-01-01

    AIM: To investigate the tumor-suppressive effect of the phosphatase and tensin homologue deleted from chromosome (PTEN) in human gastric cancer cells th atwere wild type for PTEN.METHODS: Adenoviruses expressing PTEN or luciferase as a control were introduced into gastric cancer cells.The effect of exogenous PTEN gene on the growth and apoptosis of gastric cancer cells that are wtPTEN were examined in vitro and in vivo.RESULTS: Adenovirus-mediated transfer of PTEN (AdPTEN) suppressed cell growth and induced apoptosis significantly in gastric cancer cells (MGC-803, SGC-7901)carrying wtPTEN in comparison with that in normal gastric epithelial cells (GES-1) carrying wtPTEN. This suppression was induced through downregulation of the Akt/PKB pathway, dephosphorylation of focal adhesion kinase and mitogen-activated protein kinase and cell-cycle arrest at the G2/M phase but not at the G1 phase. Furthermore,treatment of human gastric tumor xenografts (MGC-803,SGC-7901) with Ad-PTEN resulted in a significant (P<0.01)suppression of tumor growth.CONCLUSION: These results indicate a significant tumorsuppressive effect of Ad-PTEN against human gastric cancer cells. Thus, Ad-PTEN may be used as a potential therapeutic strategy for treatment of gastric cancers.

  20. Activating PTEN by COX-2 inhibitors antagonizes radiation-induced AKT activation contributing to radiosensitization

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Zhen [Central Laboratory, Peking University School and Hospital of Stomatology, 22 Zhongguancun Avenue South, Haidian District, Beijing 100081 (China); Department of Oral & Maxillofacial Surgery, Peking University School and Hospital of Stomatology, 22 Zhongguancun Avenue South, Haidian District, Beijing 100081 (China); Gan, Ye-Hua, E-mail: kqyehuagan@bjmu.edu.cn [Central Laboratory, Peking University School and Hospital of Stomatology, 22 Zhongguancun Avenue South, Haidian District, Beijing 100081 (China); Department of Oral & Maxillofacial Surgery, Peking University School and Hospital of Stomatology, 22 Zhongguancun Avenue South, Haidian District, Beijing 100081 (China)

    2015-05-01

    Radiotherapy is still one of the most effective nonsurgical treatments for many tumors. However, radioresistance remains a major impediment to radiotherapy. Although COX-2 inhibitors can induce radiosensitization, the underlying mechanism is not fully understood. In this study, we showed that COX-2 selective inhibitor celecoxib enhanced the radiation-induced inhibition of cell proliferation and apoptosis in HeLa and SACC-83 cells. Treatment with celecoxib alone dephosphorylated phosphatase and tensin homolog deleted on chromosome ten (PTEN), promoted PTEN membrane translocation or activation, and correspondingly dephosphorylated or inactivated protein kinase B (AKT). By contrast, treatment with radiation alone increased PTEN phosphorylation, inhibited PTEN membrane translocation and correspondingly activated AKT in the two cell lines. However, treatment with celecoxib or another COX-2 selective inhibitor (valdecoxib) completely blocked radiation-induced increase of PTEN phosphorylation, rescued radiation-induced decrease in PTEN membrane translocation, and correspondingly inactivated AKT. Moreover, celecoxib could also upregulate PTEN protein expression by downregulating Sp1 expression, thereby leading to the activation of PTEN transcription. Our results suggested that COX-2 inhibitors could enhance radiosensitization at least partially by activating PTEN to antagonize radiation-induced AKT activation. - Highlights: • COX-2 inhibitor, celecoxib, could enhance radiosensitization. • Radiation induced PTEN inactivation (phosphorylation) and AKT activation. • COX-2 inhibitor induced PTEN expression and activation, and inactivated AKT. • COX-2 inhibitor enhanced radiosensitization through activating PTEN.

  1. Phosphorylation of PTEN at STT motif is associated with DNA damage response.

    Science.gov (United States)

    Misra, Sandip; Mukherjee, Ananda; Karmakar, Parimal

    2014-12-01

    Phosphatase and tensin homolog deleted on chromosome Ten (PTEN), a tumor suppressor protein participates in multiple cellular activities including DNA repair. In this work we found a relationship between phosphorylation of carboxy (C)-terminal STT motif of PTEN and DNA damage response. Ectopic expression of C-terminal phospho-mutants of PTEN, in PTEN deficient human glioblastoma cells, U87MG, resulted in reduced viability and DNA repair after etoposide induced DNA damage compared to cells expressing wild type PTEN. Also, after etoposide treatment phosphorylation of PTEN increased at C-terminal serine 380 and threonine 382/383 residues in PTEN positive HEK293T cells and wild type PTEN transfected U87MG cells. One-step further, DNA damage induced phosphorylation of PTEN was confirmed by immunoprecipitation of total PTEN from cellular extract followed by immunobloting with phospho-specific PTEN antibodies. Additionally, phospho-PTEN translocated to nucleus after etoposide treatment as revealed by indirect immunolabeling. Further, phosphorylation dependent nuclear foci formation of PTEN was observed after ionizing radiation or etoposide treatment which colocalized with γH2AX. Additionally, etoposide induced γH2AX, Mre11 and Ku70 foci persisted for a longer period of times in U87MG cells after ectopic expression of PTEN C-terminal phospho-mutant constructs compared to wild type PTEN expressing cells. Thus, our findings strongly suggest that DNA damage induced phosphorylation of C-terminal STT motif of PTEN is necessary for DNA repair. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Studies of variability in the PTEN gene among Danish caucasian patients with Type II diabetes mellitus

    DEFF Research Database (Denmark)

    Hansen, L; Jensen, J N; Ekstrøm, C T

    2001-01-01

    Phosphatase and tensin homologue deleted from chromosome ten (PTEN) has recently been characterized as a novel member in the expanding network of proteins regulating the intracellular effects of insulin. By dephosphorylation of phosphatidyl-inositol-(3, 4, 5)-trisphosphate (PIP3) the PTEN protein...

  3. Nonreceptor protein tyrosine and lipid phosphatases in type I fc(epsilon) receptor-mediated activation of mast cells and basophils.

    Science.gov (United States)

    Heneberg, Petr; Dráber, Petr

    2002-08-01

    Protein tyrosine and lipid phosphorylations are early and critical events in type 1 Fc(epsilon) receptor (Fc(epsilon)RI)-mediated activation of mast cells and basophils. Tyrosine phosphorylation of Fc(epsilon)RI subunits as well as other signal transduction molecules reflects the balance between the action of protein tyrosine kinases and phosphatases. Similarly, the phosphate content of inositol phospholipids, involved in the recruitment of signalling molecules to the plasma membrane and the generation of secondary messengers, is the net result of the opposing effects of phosphoinositide kinases and lipid phosphatases. This review summarizes the current understanding of the structural and functional aspects of nonreceptor protein tyrosine phosphatases (SHP-1, SHP-2, HePTP, PTP20, PRL1, PRL2, PTP-MEG1 and PTP-MEG2) and lipid phosphatases (SHIP and SHIP2) in the activation of mast cells and basophils after Fc(epsilon)RI aggregation. New approaches towards a deeper understanding of the role of phosphatases in mast cell physiology are also discussed.

  4. Nonalcoholic fatty liver disease progression in rats is accelerated by splenic regulation of liver PTEN/AKT

    Directory of Open Access Journals (Sweden)

    Ziming Wang

    2015-01-01

    Full Text Available Background/Aim: The spleen has been reported to participate in the development of nonalcoholic fatty liver disease (NAFLD, but the mechanism has not been fully characterized. This study aims to elucidate how the spleen affects the development of NAFLD in a rat model. Materials and Methods: Following either splenectomy or sham operation, male Sprague–Dawley (SD rats were fed a high-fat diet to drive the development of NAFLD; animals fed a normal diet were used as controls. Two months after surgery, livers and blood samples were collected. Serum lipids were measured; liver histology, phosphatase and tensin homologue deleted on chromosome 10 (PTEN gene expression, and the ratio of pAkt/Akt were determined. Results: Splenectomy increased serum lipids, except triglyceride (TG and high-density lipoprotein (HDL, in animals fed either a high-fat or normal diet. Furthermore, splenectomy significantly accelerated hepatic steatosis. Western blot analysis and real-time polymerase chain reaction showed splenectomy induced significant downregulation of PTEN expression and a high ratio of pAkt/Akt in the livers. Conclusions: The spleen appears to play a role in the development of NAFLD, via a mechanism involving downregulation of hepatic PTEN expression.

  5. Nuclear trafficking of Pten after brain injury leads to neuron survival not death.

    Science.gov (United States)

    Goh, Choo-Peng; Putz, Ulrich; Howitt, Jason; Low, Ley-Hian; Gunnersen, Jenny; Bye, Nicole; Morganti-Kossmann, Cristina; Tan, Seong-Seng

    2014-02-01

    There is controversy whether accumulation of the tumor suppressor PTEN protein in the cell nucleus under stress conditions such as trauma and stroke causes cell death. A number of in vitro studies have reported enhanced apoptosis in neurons possessing nuclear PTEN, with the interpretation that its nuclear phosphatase activity leads to reduction of the survival protein phospho-Akt. However, there have been no in vivo studies to show that nuclear PTEN in neurons under stress is detrimental. Using a mouse model of injury, we demonstrate here that brain trauma altered the nucleo-cytoplasmic distribution of Pten, resulting in increased nuclear Pten but only in surviving neurons near the lesion. This event was driven by Ndfip1, an adaptor and activator of protein ubiquitination by Nedd4 E3 ligases. Neurons next to the lesion with nuclear PTEN were invariably negative for TUNEL, a marker for cell death. These neurons also showed increased Ndfip1 which we previously showed to be associated with neuron survival. Biochemical assays revealed that overall levels of Pten in the affected cortex were unchanged after trauma, suggesting that Pten abundance globally had not increased but rather Pten subcellular location in affected neurons had changed. Following experimental injury, the number of neurons with nuclear Pten was reduced in heterozygous mice (Ndfip1(+/-)) although lesion volumes were increased. We conclude that nuclear trafficking of Pten following injury leads to neuron survival not death.

  6. Mutations of the KIT gene and loss of heterozygosity of the PTEN region in a primary malignant melanoma arising from a mature cystic teratoma of the ovary.

    Science.gov (United States)

    Tate, Genshu; Tajiri, Takuma; Suzuki, Takao; Mitsuya, Toshiyuki

    2009-04-01

    A tumor suppressor gene at 10q23.3, designated PTEN, encoding a dual-specificity phosphatase with lipid and protein phosphatase activity, has been shown to play a pivotal role in the pathogenesis of a variety of human cancers. A frequent loss of heterozygosity (LOH) at 10q is found in melanoma; however, little is known about the role of PTEN in the pathogenesis of a primary malignant melanoma derived from ovarian mature cystic teratoma, which is an extremely rare melanoma. This study examined the genetic alterations involved in the mitogen-activated protein kinase and phosphatidylinositol 3 kinase pathways in an ovarian malignant melanoma. A LOH analysis revealed hemizygous deletion around and in the PTEN gene not only in the ovarian melanoma but also in a mature cystic teratoma. Another case of ovarian mature cystic teratomas in the absence of melanoma also showed allelic loss of the PTEN region. To date, mutations of BRAF, NRAS, and KIT genes have been reported in malignant melanomas. In the present study, D816H and K558E mutations of the KIT gene were revealed in the melanoma arising from a mature cystic teratoma, but not in a mature cystic teratoma. No mutations of the BRAF and NRAS genes were found in the melanoma. These results indicate that LOH of the PTEN region is one of the molecular alterations of an ovarian mature cystic teratoma and a KIT mutation is an additional promotional event associated with the oncogenesis of a melanoma arising from an ovarian mature cystic teratoma.

  7. New Functions of the Inositol Polyphosphate 5-Phosphatases in Cancer.

    Science.gov (United States)

    Erneux, Christophe; Ghosh, Somadri; Ramos, Ana Raquel; Edimo, William's Elong

    2016-01-01

    Inositol polyphosphate 5-phosphatases act on inositol phosphates and phosphoinositides as substrates. They are 10 different isoenzymes and several splice variants in the human genome that are involved in a series of human pathologies such as the Lowe syndrome, the Joubert and MORM syndromes, breast cancer, glioblastoma, gastric cancer and several other type of cancers. Inositol 5-phosphatases can be amplified in human cancer cells, whereas the 3- and 4- phosphatase tumor suppressor PTEN and INPP4B, repectively are often repressed or deleted. The inositol 5-phosphatases are critically involved in a complex network of higly regulated phosphoinositides, affecting the lipid content of PI(3, 4, 5)P3, PI(4, 5)P2 and PI(3, 4)P2. This has an impact on the normal behavior of many intracellular target proteins e.g. protein kinase B (PKB/Akt) or actin binding proteins and final biological responses. The production of PI(3, 4P)2 by dephosphorylation of the substrate PI(3, 4, 5)P3 is particularly important as it produces a new signal messenger in the control of cell migration, invasion and endocytosis. New inhibitors/activators of inositol 5- phosphatases have recently been identified for the possible control of their activity in several human pathologies such as inflamation and cancer.

  8. Loss of catalytically inactive lipid phosphatase myotubularin-related protein 12 impairs myotubularin stability and promotes centronuclear myopathy in zebrafish.

    Science.gov (United States)

    Gupta, Vandana A; Hnia, Karim; Smith, Laura L; Gundry, Stacey R; McIntire, Jessica E; Shimazu, Junko; Bass, Jessica R; Talbot, Ethan A; Amoasii, Leonela; Goldman, Nathaniel E; Laporte, Jocelyn; Beggs, Alan H

    2013-06-01

    X-linked myotubular myopathy (XLMTM) is a congenital disorder caused by mutations of the myotubularin gene, MTM1. Myotubularin belongs to a large family of conserved lipid phosphatases that include both catalytically active and inactive myotubularin-related proteins (i.e., "MTMRs"). Biochemically, catalytically inactive MTMRs have been shown to form heteroligomers with active members within the myotubularin family through protein-protein interactions. However, the pathophysiological significance of catalytically inactive MTMRs remains unknown in muscle. By in vitro as well as in vivo studies, we have identified that catalytically inactive myotubularin-related protein 12 (MTMR12) binds to myotubularin in skeletal muscle. Knockdown of the mtmr12 gene in zebrafish resulted in skeletal muscle defects and impaired motor function. Analysis of mtmr12 morphant fish showed pathological changes with central nucleation, disorganized Triads, myofiber hypotrophy and whorled membrane structures similar to those seen in X-linked myotubular myopathy. Biochemical studies showed that deficiency of MTMR12 results in reduced levels of myotubularin protein in zebrafish and mammalian C2C12 cells. Loss of myotubularin also resulted in reduction of MTMR12 protein in C2C12 cells, mice and humans. Moreover, XLMTM mutations within the myotubularin interaction domain disrupted binding to MTMR12 in cell culture. Analysis of human XLMTM patient myotubes showed that mutations that disrupt the interaction between myotubularin and MTMR12 proteins result in reduction of both myotubularin and MTMR12. These studies strongly support the concept that interactions between myotubularin and MTMR12 are required for the stability of their functional protein complex in normal skeletal muscles. This work highlights an important physiological function of catalytically inactive phosphatases in the pathophysiology of myotubular myopathy and suggests a novel therapeutic approach through identification of drugs

  9. Loss of catalytically inactive lipid phosphatase myotubularin-related protein 12 impairs myotubularin stability and promotes centronuclear myopathy in zebrafish.

    Directory of Open Access Journals (Sweden)

    Vandana A Gupta

    2013-06-01

    Full Text Available X-linked myotubular myopathy (XLMTM is a congenital disorder caused by mutations of the myotubularin gene, MTM1. Myotubularin belongs to a large family of conserved lipid phosphatases that include both catalytically active and inactive myotubularin-related proteins (i.e., "MTMRs". Biochemically, catalytically inactive MTMRs have been shown to form heteroligomers with active members within the myotubularin family through protein-protein interactions. However, the pathophysiological significance of catalytically inactive MTMRs remains unknown in muscle. By in vitro as well as in vivo studies, we have identified that catalytically inactive myotubularin-related protein 12 (MTMR12 binds to myotubularin in skeletal muscle. Knockdown of the mtmr12 gene in zebrafish resulted in skeletal muscle defects and impaired motor function. Analysis of mtmr12 morphant fish showed pathological changes with central nucleation, disorganized Triads, myofiber hypotrophy and whorled membrane structures similar to those seen in X-linked myotubular myopathy. Biochemical studies showed that deficiency of MTMR12 results in reduced levels of myotubularin protein in zebrafish and mammalian C2C12 cells. Loss of myotubularin also resulted in reduction of MTMR12 protein in C2C12 cells, mice and humans. Moreover, XLMTM mutations within the myotubularin interaction domain disrupted binding to MTMR12 in cell culture. Analysis of human XLMTM patient myotubes showed that mutations that disrupt the interaction between myotubularin and MTMR12 proteins result in reduction of both myotubularin and MTMR12. These studies strongly support the concept that interactions between myotubularin and MTMR12 are required for the stability of their functional protein complex in normal skeletal muscles. This work highlights an important physiological function of catalytically inactive phosphatases in the pathophysiology of myotubular myopathy and suggests a novel therapeutic approach through

  10. The PTEN/NRF2 Axis Promotes Human Carcinogenesis

    DEFF Research Database (Denmark)

    Rojo, Ana I; Rada, Patricia; Mendiola, Marta;

    2014-01-01

    UNLABELLED: Abstract Aims: A recent study conducted in mice reported that liver-specific knockout of tumor suppressor Pten augments nuclear factor (erythroid-derived 2)-like 2 (NRF2) transcriptional activity. Here, we further investigated how phosphatase and tensin homolog deleted on chromosome 1...

  11. PTEN inhibition and axon regeneration and neural repair

    Institute of Scientific and Technical Information of China (English)

    Yosuke Ohtake; Umar Hayat; Shuxin Li

    2015-01-01

    The intrinsic growth ability of all the neurons declines during development although some may grow better than others. Numerous intracellular signaling proteins and transcription factors have been shown to regulate the intrinsic growth capacity in mature neurons. Among them, PI3 kinase/Akt pathway is important for controlling axon elongation. As a negative regulator of this pathway, the tumor suppressor phosphatase and tensin homolog (PTEN) appears critical to con-trol the regenerative ability of young and adult neurons. This review will focus on recent research progress in axon regeneration and neural repair by PTEN inhibition and therapeutic potential of blocking this phosphatase for neurological disorders. Inhibition of PTEN by deletion in con-ditional knockout mice, knockdown by short-hairpin RNA, or blockade by pharmacological approaches, including administration of selective PTEN antagonist peptides, stimulates various degrees of axon regrowth in juvenile or adult rodents with central nervous system injuries. Im-portantly, post-injury PTEN suppression could enhance axonal growth and functional recovery in adult central nervous system after injury.

  12. Molecular Analysis of AFP and HSA Interactions with PTEN Protein.

    Science.gov (United States)

    Zhu, Mingyue; Lin, Bo; Zhou, Peng; Li, Mengsen

    2015-01-01

    Human cytoplasmic alpha-fetoprotein (AFP) has been classified as a member of the albuminoid gene family. The protein sequence of AFP has significant homology to that of human serum albumin (HSA), but its biological characteristics are vastly different from HSA. The AFP functions as a regulator in the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) pathway, but HSA plays a key role as a transport protein. To probe their molecular mechanisms, we have applied colocalization, coimmunoprecipitation (co-IP), and molecular docking approaches to analyze the differences between AFP and HSA. The data from colocalization and co-IP displayed a strong interaction between AFP and PTEN (phosphatase and tensin homolog), demonstrating that AFP did bind to PTEN, but HSA did not. The molecular docking study further showed that the AFP domains I and III could contact with PTEN. In silicon substitutions of AFP binding site residues at position 490M/K and 105L/R corresponding to residues K490 and R105 in HSA resulted in steric clashes with PTEN residues R150 and K46, respectively. These steric clashes may explain the reason why HSA cannot bind to PTEN. Ultimately, the experimental results and the molecular modeling data from the interactions of AFP and HSA with PTEN will help us to identify targets for designing drugs and vaccines against human hepatocellular carcinoma.

  13. Loss of PTEN causes SHP2 activation, making lung cancer cells unresponsive to IFN-γ

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chia-Ling [Translational Research Center, Taipei Medical University, Taipei 110, Taiwan (China); Chiang, Tzu-Hui; Tseng, Po-Chun [Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan (China); Wang, Yu-Chih [Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan (China); Lin, Chiou-Feng, E-mail: cflin2014@tmu.edu.tw [Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan (China); Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei 110, Taiwan (China)

    2015-10-23

    Src homology-2 domain-containing phosphatase (SHP) 2, an oncogenic phosphatase, inhibits type II immune interferon (IFN)-γ signaling by subverting signal transducers and activators of transcription 1 tyrosine phosphorylation and activation. For cancer immunoediting, this study aimed to investigate the decrease of phosphatase and tensin homolog deleted on chromosome 10 (PTEN), a tumor suppressor protein, leading to cellular impairment of IFN-γ signaling. In comparison with human lung adenocarcinoma A549 cells, the natural PTEN loss in another human lung adenocarcinoma line, PC14PE6/AS2 cells, presents reduced responsiveness in IFN-γ-induced IFN regulatory factor 1 activation and CD54 expression. Artificially silencing PTEN expression in A549 cells also caused cells to be unresponsive to IFN-γ without affecting IFN-γ receptor expression. IFN-γ-induced inhibition of cell proliferation and cytotoxicity were demonstrated in A549 cells but were defective in PC14PE6/AS2 cells and in PTEN-deficient A549 cells. Aberrant activation of SHP2 by ROS was specifically shown in PC14PE6/AS2 cells and PTEN-deficient A549 cells. Inhibiting ROS and SHP2 rescued cellular responses to IFN-γ-induced cytotoxicity and inhibition of cell proliferation in PC14PE6/AS2 cells. These results demonstrate that a decrease in PTEN facilitates ROS/SHP2 signaling, causing lung cancer cells to become unresponsive to IFN-γ. - Highlights: • This study demonstrates that PTEN decrease causes cellular unresponsive to IFN-γ. • Lung cancer cells with PTEN deficiency show unresponsive to IFN-γ signaling. • PTEN decrease inhibits IFN-γ-induced CD54, cell proliferation inhibition, and cytotoxicity. • ROS-mediated SHP2 activation makes PTEN-deficient cells unresponsive to IFN-γ.

  14. Cell-Type Specific Roles for PTEN in Establishing a Functional Retinal Architecture

    Science.gov (United States)

    Cantrup, Robert; Dixit, Rajiv; Palmesino, Elena; Bonfield, Stephan; Shaker, Tarek; Tachibana, Nobuhiko; Zinyk, Dawn; Dalesman, Sarah; Yamakawa, Kazuhiro; Stell, William K.; Wong, Rachel O.; Reese, Benjamin E.; Kania, Artur; Sauvé, Yves; Schuurmans, Carol

    2012-01-01

    Background The retina has a unique three-dimensional architecture, the precise organization of which allows for complete sampling of the visual field. Along the radial or apicobasal axis, retinal neurons and their dendritic and axonal arbors are segregated into layers, while perpendicular to this axis, in the tangential plane, four of the six neuronal types form patterned cellular arrays, or mosaics. Currently, the molecular cues that control retinal cell positioning are not well-understood, especially those that operate in the tangential plane. Here we investigated the role of the PTEN phosphatase in establishing a functional retinal architecture. Methodology/Principal Findings In the developing retina, PTEN was localized preferentially to ganglion, amacrine and horizontal cells, whose somata are distributed in mosaic patterns in the tangential plane. Generation of a retina-specific Pten knock-out resulted in retinal ganglion, amacrine and horizontal cell hypertrophy, and expansion of the inner plexiform layer. The spacing of Pten mutant mosaic populations was also aberrant, as were the arborization and fasciculation patterns of their processes, displaying cell type-specific defects in the radial and tangential dimensions. Irregular oscillatory potentials were also observed in Pten mutant electroretinograms, indicative of asynchronous amacrine cell firing. Furthermore, while Pten mutant RGC axons targeted appropriate brain regions, optokinetic spatial acuity was reduced in Pten mutant animals. Finally, while some features of the Pten mutant retina appeared similar to those reported in Dscam-mutant mice, PTEN expression and activity were normal in the absence of Dscam. Conclusions/Significance We conclude that Pten regulates somal positioning and neurite arborization patterns of a subset of retinal cells that form mosaics, likely functioning independently of Dscam, at least during the embryonic period. Our findings thus reveal an unexpected level of cellular

  15. Cell-type specific roles for PTEN in establishing a functional retinal architecture.

    Directory of Open Access Journals (Sweden)

    Robert Cantrup

    Full Text Available BACKGROUND: The retina has a unique three-dimensional architecture, the precise organization of which allows for complete sampling of the visual field. Along the radial or apicobasal axis, retinal neurons and their dendritic and axonal arbors are segregated into layers, while perpendicular to this axis, in the tangential plane, four of the six neuronal types form patterned cellular arrays, or mosaics. Currently, the molecular cues that control retinal cell positioning are not well-understood, especially those that operate in the tangential plane. Here we investigated the role of the PTEN phosphatase in establishing a functional retinal architecture. METHODOLOGY/PRINCIPAL FINDINGS: In the developing retina, PTEN was localized preferentially to ganglion, amacrine and horizontal cells, whose somata are distributed in mosaic patterns in the tangential plane. Generation of a retina-specific Pten knock-out resulted in retinal ganglion, amacrine and horizontal cell hypertrophy, and expansion of the inner plexiform layer. The spacing of Pten mutant mosaic populations was also aberrant, as were the arborization and fasciculation patterns of their processes, displaying cell type-specific defects in the radial and tangential dimensions. Irregular oscillatory potentials were also observed in Pten mutant electroretinograms, indicative of asynchronous amacrine cell firing. Furthermore, while Pten mutant RGC axons targeted appropriate brain regions, optokinetic spatial acuity was reduced in Pten mutant animals. Finally, while some features of the Pten mutant retina appeared similar to those reported in Dscam-mutant mice, PTEN expression and activity were normal in the absence of Dscam. CONCLUSIONS/SIGNIFICANCE: We conclude that Pten regulates somal positioning and neurite arborization patterns of a subset of retinal cells that form mosaics, likely functioning independently of Dscam, at least during the embryonic period. Our findings thus reveal an unexpected

  16. A role for Pten in paediatric intestinal dysmotility disorders.

    LENUS (Irish Health Repository)

    O'Donnell, Anne-Marie

    2012-02-01

    PURPOSE: The enteric nervous system (ENS) is a network of neurons and glia that lies within the gut wall. It is responsible for the normal regulation of gut motility and secretory activities. Hirschsprung\\'s disease (HD) is a congenital defect of the ENS, characterised by an absence of ganglia in the distal colon. Intestinal neuronal dysplasia (IND) is a condition that clinically resembles HD, characterised by hyperganglionosis, giant and ectopic ganglia, resulting in intestinal dysmotility. Intestinal ganglioneuromatosis is characterised by hyperplasia and hypertrophy of enteric neuronal cells and causes chronic intestinal pseudo-obstruction (CIPO). Phosphatase and tensin homolog deleted on chromosome 10 (Pten) is a phosphatase that is critical for controlling cell growth, proliferation and cell death. A recent study of Pten knockout mice showed evidence of ganglioneuromatosis in the ENS suggesting a role for this protein in ENS development. Ganglioneuromatosis patients have also been shown to have a decreased level of Pten expression in the colon. The aim of our study was to investigate Pten expression in the ENS of HD and IND patients compared to normal controls. METHODS: Resected tissue from 10 HD and 10 IND type B patients was fixed and embedded in paraffin wax. Normal control colon tissue was obtained from ten patients who underwent a colostomy closure for imperforate anus. Sections were cut and immunohistochemistry was carried out using a Pten antibody. Results were analysed by light microscopy. RESULTS: Staining showed that Pten was strongly expressed in ganglia of both the submucosal and myenteric plexus of normal and HD specimens from the ganglionic colon. Pten expression was significantly reduced in the giant ganglia in IND patients in both the myenteric and submucosal plexuses compared to the normal controls. Specimens from the aganglionic region of HD did not show Pten expression. CONCLUSION: To the best of our knowledge, this is the first study

  17. Inhibition of lipid phosphate phosphatase activity by VPC32183 suppresses the ability of diacylglycerol pyrophosphate to activate ERK(1/2) MAP kinases.

    Science.gov (United States)

    Violet, Pierre-Christian; Billon-Denis, Emmanuelle; Robin, Philippe

    2012-11-01

    The lipidic metabolite, diacylglycerol pyrophosphate (DGPP), in its dioctanoyl form (DGPP 8:0), has been described as an antagonist for mammalian lysophosphatidic acid (LPA) receptors LPA1 and LPA3. In this study we show that DGPP 8:0 does not antagonize LPA dependent activation of ERK(1/2) MAP kinases but strongly stimulated them in various mammalian cell lines. LPA and DGPP 8:0 stimulation of ERK(1/2) occurred through different pathways. The DGPP 8:0 effect appeared to be dependent on PKC, Raf and MEK but was insensitive to pertussis toxin and did not involve G protein activation. Finally we showed that DGPP 8:0 effect on ERK(1/2) was dependent on its dephosphorylation by a phosphatase activity sharing lipid phosphate phosphatase properties. The inhibition of this phosphatase activity by VPC32183, a previously characterized LPA receptor antagonist, blocked the DGPP 8:0 effect on ERK(1/2) activation. Moreover, down-regulation of lipid phosphate phosphatase 1 (LPP1) expression by RNA interference technique also reduced DGPP 8:0-induced ERK(1/2) activation. Consistently, over expression of LPP1 in HEK293 cells increases DGPP 8:0 hydrolysis and this increased activity was inhibited by VPC32183. In conclusion, DGPP 8:0 does not exert its effect by acting on a G protein coupled receptor, but through its dephosphorylation by LPP1, generating dioctanoyl phosphatidic acid which in turn activates PKC. These results suggest that LPP1 could have a positive regulatory function on cellular signaling processes such as ERK(1/2) activation.

  18. Expression of PPARγ and PTEN in human colorectal cancer: An immunohistochemical study using tissue microarray methodology.

    Science.gov (United States)

    Lin, Mao Song; Huang, Jun Xing; Chen, Wei Chang; Zhang, Bao Feng; Fang, Jing; Zhou, Qiong; Hu, Ying; Gao, Heng Jun

    2011-11-01

    Although aberrations of peroxisome proliferator-activated receptor γ (PPARγ) and phosphatase and tensin homolog (PTEN) expression have been identified in several other cancer types, certain previous studies have revealed that PPARγ is abundant in normal and malignant tissue in the colon. The question of whether aberrant PTEN is involved in the initial stage or is a later event during colorectal carcinogenesis remains controversial. Relatively few studies have focused on the correlation of expression of PPARγ and PTEN in various tissues. In the present study, paraffin-embedded blocks from 139 patients with CRC, 18 adenomatous polyps and 50 paired paracancerous benign mucosas were selected and analysed in 4 tissue microarray (TMA) blocks comprising 104, 72, 130 and 54 cores, respectively. Expression of PPARγ and PTEN was examined using immunohistochemical staining on TMAs. There were no significant differences in the expression of PPARγ (P=0.055) and PTEN (P=0.100) between the colorectal cancers, adenomas and paracancerous mucosas. However, correlations of PPARγ expression with clinical stage (P=0.004) and PTEN expression with histological grade (P=0.006) and distant metastasis (P=0.015) were demonstrated in the CRC specimens. Although the differences in PPARγ and PTEN protein expression in human colorectal cancer may not be considered as early diagnostic markers, our results indicate that CRCs with a low expression or deletion of PTEN may progress towards invasion and even metastasis; thus, PTEN may have potential as a prognostic marker in human CRC.

  19. Selective neuronal PTEN deletion: can we take the brakes off of growth without losing control?

    Science.gov (United States)

    Gutilla, Erin A; Steward, Oswald

    2016-08-01

    The limited ability for injured adult axons to regenerate is a major cause for limited functional recovery after injury to the nervous system, motivating numerous efforts to uncover mechanisms capable of enhancing regeneration potential. One promising strategy involves deletion or knockdown of the phosphatase and tensin (PTEN) gene. Conditional genetic deletion of PTEN before, immediately following, or several months after spinal cord injury enables neurons of the corticospinal tract (CST) to regenerate their axons across the lesion, which is accompanied by enhanced recovery of skilled voluntary motor functions mediated by the CST. Although conditional genetic deletion or knockdown of PTEN in neurons enables axon regeneration, PTEN is a well-known tumor suppressor and mutations of the PTEN gene disrupt brain development leading to neurological abnormalities including macrocephaly, seizures, and early mortality. The long-term consequences of manipulating PTEN in the adult nervous system, as would be done for therapeutic intervention after injury, are only now being explored. Here, we summarize evidence indicating that long-term deletion of PTEN in mature neurons does not cause evident pathology; indeed, cortical neurons that have lived without PTEN for over 1 year appear robust and healthy. Studies to date provide only a first look at potential negative consequences of PTEN deletion or knockdown, but the absence of any detectable neuropathology supports guarded optimism that interventions to enable axon regeneration after injury are achievable.

  20. Selective neuronal PTEN deletion: can we take the brakes off of growth without losing control?

    Directory of Open Access Journals (Sweden)

    Erin A Gutilla

    2016-01-01

    Full Text Available The limited ability for injured adult axons to regenerate is a major cause for limited functional recovery after injury to the nervous system, motivating numerous efforts to uncover mechanisms capable of enhancing regeneration potential. One promising strategy involves deletion or knockdown of the phosphatase and tensin (PTEN gene. Conditional genetic deletion of PTEN before, immediately following, or several months after spinal cord injury enables neurons of the corticospinal tract (CST to regenerate their axons across the lesion, which is accompanied by enhanced recovery of skilled voluntary motor functions mediated by the CST. Although conditional genetic deletion or knockdown ofPTEN in neurons enables axon regeneration, PTEN is a well-known tumor suppressor and mutations of the PTEN gene disrupt brain development leading to neurological abnormalities including macrocephaly, seizures, and early mortality. The long-term consequences of manipulating PTEN in the adult nervous system, as would be done for therapeutic intervention after injury, are only now being explored. Here, we summarize evidence indicating that long-term deletion of PTEN in mature neurons does not cause evident pathology; indeed, cortical neurons that have lived without PTEN for over 1 year appear robust and healthy. Studies to date provide only a first look at potential negative consequences of PTEN deletion or knockdown, but the absence of any detectable neuropathology supports guarded optimism that interventions to enable axon regeneration after injury are achievable.

  1. Phosphatase and Tensin Homologue: Novel Regulation by Developmental Signaling

    Directory of Open Access Journals (Sweden)

    Travis J. Jerde

    2015-01-01

    Full Text Available Phosphatase and tensin homologue (PTEN is a critical cell endogenous inhibitor of phosphoinositide signaling in mammalian cells. PTEN dephosphorylates phosphoinositide trisphosphate (PIP3, and by so doing PTEN has the function of negative regulation of Akt, thereby inhibiting this key intracellular signal transduction pathway. In numerous cell types, PTEN loss-of-function mutations result in unopposed Akt signaling, producing numerous effects on cells. Numerous reports exist regarding mutations in PTEN leading to unregulated Akt and human disease, most notably cancer. However, less is commonly known about nonmutational regulation of PTEN. This review focuses on an emerging literature on the regulation of PTEN at the transcriptional, posttranscriptional, translational, and posttranslational levels. Specifically, a focus is placed on the role developmental signaling pathways play in PTEN regulation; this includes insulin-like growth factor, NOTCH, transforming growth factor, bone morphogenetic protein, wnt, and hedgehog signaling. The regulation of PTEN by developmental mediators affects critical biological processes including neuronal and organ development, stem cell maintenance, cell cycle regulation, inflammation, response to hypoxia, repair and recovery, and cell death and survival. Perturbations of PTEN regulation consequently lead to human diseases such as cancer, chronic inflammatory syndromes, developmental abnormalities, diabetes, and neurodegeneration.

  2. Hepatitis B virus induces cell proliferation via HBx-induced microRNA-21 in hepatocellular carcinoma by targeting programmed cell death protein4 (PDCD4 and phosphatase and tensin homologue (PTEN.

    Directory of Open Access Journals (Sweden)

    Preeti Damania

    Full Text Available Hepatitis B viral infection-induced hepatocellular carcinoma is one of the major problems in the developing countries. One of the HBV proteins, HBx, modulates the host cell machinery via several mechanisms. In this study we hypothesized that HBV enhances cell proliferation via HBx-induced microRNA-21 in hepatocellular carcinoma. HBx gene was over-expressed, and miRNA-21 expression and cell proliferation were measured in Huh 7 and Hep G2 cells. miRNA-21 was over-expressed in these cells, cell proliferation and the target proteins were analyzed. To confirm the role of miRNA-21 in HBx-induced proliferation, Hep G 2.2.1.5 cells (a cell line that expresses HBV stably were used for miRNA-21 inhibition studies. HBx over-expression enhanced proliferation (3.7- and 4.5-fold increase; n = 3; p<0.01 and miRNA-21 expression (24- and 36-fold increase, normalized with 5S rRNA; p<0.001 in Huh 7 and Hep G2 cells respectively. HBx also resulted in the inhibition of miRNA-21 target proteins, PDCD4 and PTEN. miRNA-21 resulted in a significant increase in proliferation (2- and 2.3-fold increase over control cells; p<0.05 in Huh 7 and Hep G2 cells respectively and decreased target proteins, PDCD4 and PTEN expression. Anti-miR-21 resulted in a significant decrease in proliferation (p<0.05 and increased miRNA-21 target protein expression. We conclude that HBV infection enhances cell proliferation, at least in part, via HBx-induced miRNA-21 expression during hepatocellular carcinoma progression.

  3. Reprogramming of the Tumor Microenvironment by Stromal Pten-regulated miR-320

    Science.gov (United States)

    Bronisz, A; Godlewski, J; Wallace, JA; Merchant, AS; Nowicki, MO; Mathsyaraja, H; Srinivasan, R; Trimboli, AJ; Martin, CK; Li, F; Yu, L; Fernandez, SA; Pécot, T; Rosol, TJ; Cory, S; Hallett, M; Park, M; Piper, MG; Marsh, CB; Yee, LD; Jimenez, RE; Nuovo, G; Lawler, SE; Chiocca, EA; Leone, G; Ostrowski, MC

    2011-01-01

    Phosphatase and tensin homolog deleted on chromosome ten (Pten) in stromal fibroblasts suppresses epithelial mammary tumors, but the underlying molecular mechanisms remain unknown. Using proteomic and expression profiling, we show that Pten loss from mammary stromal fibroblasts activates an oncogenic secretome that orchestrates the transcriptional reprogramming of other cell types in the microenvironment. Downregulation of miR-320 and upregulation of one of its direct targets, ETS2, are critical events in Pten-deleted stromal fibroblasts responsible for inducing this oncogenic secretome, which in turn promotes tumor angiogenesis and tumor cell invasion. Expression of the Pten-miR-320-Ets2 regulated secretome distinguished human normal breast stroma from tumor stroma and robustly correlated with recurrence in breast cancer patients. This work reveals miR-320 as a critical component of the Pten tumor suppressor axis that acts in stromal fibroblasts to reprogram the tumor microenvironment and curtail tumor progression. PMID:22179046

  4. Function of PTEN during the formation and maintenance of neuronal circuits in the brain.

    Science.gov (United States)

    van Diepen, Michiel T; Eickholt, Britta J

    2008-01-01

    PTEN (phosphatase and tensin homologue deleted on chromosome 10) is a tumor suppressor that can inhibit proliferation and migration and controls apoptosis in a number of cell types, mainly through inhibition of the phosphoinositide 3-kinase (PI3K) signaling pathway. Patients carrying inactivating mutations of PTEN show a prevalence to develop tumors that can coincide with neurological defects such as mental retardation, ataxia and seizures. A number of in vitro and in vivo studies were instrumental in uncovering a direct correlation between deregulated PI3K/PTEN signaling and changes in neuronal morphogenesis, which is likely to have profound bearings upon the pathogenesis of neurological symptoms. This review outlines recent work on the function of PTEN during vertebrate brain development and the current understanding of the signaling pathways downstream of PTEN that control neuronal connectivity in the brain.

  5. Characterization of novel non-clonal intrachromosomal rearrangements between the H4 and PTEN genes (H4/PTEN) in human thyroid cell lines and papillary thyroid cancer specimens

    Energy Technology Data Exchange (ETDEWEB)

    Puxeddu, Efisio [Division of Endocrinology and Metabolism, University of Cincinnati College of Medicine, PO Box 670547, Cincinnati, OH 45267-0547 (United States); Zhao Guisheng [Division of Endocrinology and Metabolism, University of Cincinnati College of Medicine, PO Box 670547, Cincinnati, OH 45267-0547 (United States); Stringer, James R. [Department of Molecular Genetics, University of Cincinnati College of Medicine, PO Box 670547, Cincinnati, OH 45267-0547 (United States); Medvedovic, Mario [Center for Biostatistic Service, University of Cincinnati College of Medicine, PO Box 670547, Cincinnati, OH 45267-0547 (United States); Moretti, Sonia [Dipartimento di Medicina Interna, Universita degli Studi di Perugia, Via E. dal Pozzo, Perugia 06126, (Italy); Fagin, James A. [Division of Endocrinology and Metabolism, University of Cincinnati College of Medicine, PO Box 670547, Cincinnati, OH 45267-0547 (United States)]. E-mail: james.fagin@uc.edu

    2005-02-15

    The two main forms of RET rearrangement in papillary thyroid carcinomas (PTC) arise from intrachromosomal inversions fusing the tyrosine kinase domain of RET with either the H4 (RET/PTC1) or the ELE1/RFG genes (RET/PTC3). PTEN codes for a dual-specificity phosphatase and maps to chromosome 10q22-23. Germline mutations confer susceptibility to Cowden syndrome whereas somatic mutations or deletions are common in several sporadic human tumors. Decreased PTEN expression has been implicated in thyroid cancer development. We report the characterization of a new chromosome 10 rearrangement involving H4 and PTEN. The initial H4/PTEN rearrangement was discovered as a non-specific product of RT-PCR for RET/PTC1 in irradiated thyroid cell lines. Sequencing revealed a transcript consisting of exon 1 and 2 of H4 fused with exons 3-6 of PTEN. Nested RT-PCR with specific primers bracketing the breakpoints confirmed the H4/PTEN rearrangements in irradiated KAT-1 and KAT-50 cells. Additional H4/PTEN variants, generated by recombination of either exon 1 or exon 2 of H4 with exon 6 of PTEN, were found in non-irradiated KAK-1, KAT-50, ARO and NPA cells. Their origin through chromosomal recombination was confirmed by detection of the reciprocal PTEN/H4 product. H4/PTEN recombination was not a clonal event in any of the cell lines, as Southern blots with appropriate probes failed to demonstrate aberrant bands, and multicolor FISH of KAK1 cells with BAC probes for H4 and PTEN did not show a signal overlap in all cells. Based on PCR of serially diluted samples, the minimal frequency of spontaneous recombination between these loci was estimated to be approximately 1/10{sup 6} cells. H4/PTEN products were found by nested RT-PCR in 4/14 normal thyroid tissues (28%) and 14/18 PTC (78%) (P < 0.01). H4/PTEN is another example of recombination involving the H4 locus, and points to the high susceptibility of thyroid cells to intrachromosomal gene rearrangements. As this also represents a

  6. Exogenous PTEN Gene Induces Apoptosis in Breast Carcinoma Cell Line MDA468

    Institute of Scientific and Technical Information of China (English)

    CHEN Qingyong; WANG Chunyou; JIANG Chunfang; CHEN Daoda

    2007-01-01

    The effects and mechanisms of exogenous phosphatase and tensin homolog deleted from chromosome ten (PTEN) gene on phosphatase activity-dependent apoptosis of breast cancer cell line MDA468 were investigated. PTEN gene packaged with lipofectin was transferred into breast cancer cell line MDA468 and parental MDA468 cells served as controls. RT-PCR and Western blot were done to detect the expression of target genes. The expression of phosphospecific protein kinase B (PKB/Akt) and focal adhesion kinase (FAK) protein stimulated by epidermal growth factor (EGF) was also detected. Apoptosis was determined by flow cytometry with a double-staining method using FITC-conjugated annexin V and PI. MDA468 cells transfected with PTEN gene could express PTEN mRNA and protein. PTEN decreased the phosphorylation level of AKT protein and down-regulated FAK protein expression in MDA468 stimulated by EGF. The apoptosis rate was 21.68%. PTEN induced breast cancer apoptosis phosphatase activity-dependently. The mechanism is possibly relatedwith phosphoinositide 3-kinase (PI3K)/protein kinase B (PKB)/AKT signaling pathway. Those results may provide new clues on the gene therapy in breast cancer.

  7. Lipid Emulsion Inhibits Vasodilation Induced by a Toxic Dose of Bupivacaine via Attenuated Dephosphorylation of Myosin Phosphatase Target Subunit 1 in Isolated Rat Aorta.

    Science.gov (United States)

    Ok, Seong-Ho; Byon, Hyo-Jin; Kwon, Seong-Chun; Park, Jungchul; Lee, Youngju; Hwang, Yeran; Baik, Jiseok; Choi, Mun-Jeoung; Sohn, Ju-Tae

    2015-01-01

    Lipid emulsions are widely used for the treatment of systemic toxicity that arises from local anesthetics. The goal of this in vitro study was to examine the cellular mechanism associated with the lipid emulsion-mediated attenuation of vasodilation induced by a toxic dose of bupivacaine in isolated endothelium-denuded rat aorta. The effects of lipid emulsion on vasodilation induced by bupivacaine, mepivacaine, and verapamil were assessed in isolated aorta precontracted with phenylephrine, the Rho kinase stimulant NaF, and the protein kinase C activator phorbol 12,13-dibutyrate (PDBu). The effects of Rho kinase inhibitor Y-27632 on contraction induced by phenylephrine or NaF were assessed. The effects of bupivacaine on intracellular calcium concentrations ([Ca(2+)]i) and tension induced by NaF were simultaneously measured. The effects of bupivacaine alone and lipid emulsion plus bupivacaine on myosin phosphatase target subunit 1 (MYPT1) phosphorylation induced by NaF were examined in rat aortic vascular smooth muscle cells. In precontracted aorta, the lipid emulsion attenuated bupivacaine-induced vasodilation but had no effect on mepivacaine-induced vasodilation. Y-27632 attenuated contraction induced by either phenylephrine or NaF. The lipid emulsion attenuated verapamil-induced vasodilation. Compared with phenylephrine-induced precontracted aorta, bupivacaine-induced vasodilation was slightly attenuated in NaF-induced precontracted aorta. The magnitude of the bupivacaine-induced vasodilation was higher than that of a bupivacaine-induced decrease in [Ca(2+)]i. Bupivacaine attenuated NaF-induced MYPT1 phosphorylation, whereas lipid emulsion pretreatment attenuated the bupivacaine-induced inhibition of MYPT1 phosphorylation induced by NaF. Taken together, these results suggest that lipid emulsions attenuate bupivacaine-induced vasodilation via the attenuation of inhibition of MYPT1 phosphorylation evoked by NaF.

  8. Lipid rafts regulate PCB153-induced disruption of occludin and brain endothelial barrier function through protein phosphatase 2A and matrix metalloproteinase-2.

    Science.gov (United States)

    Eum, Sung Yong; Jaraki, Dima; András, Ibolya E; Toborek, Michal

    2015-09-15

    Occludin is an essential integral transmembrane protein regulating tight junction (TJ) integrity in brain endothelial cells. Phosphorylation of occludin is associated with its localization to TJ sites and incorporation into intact TJ assembly. The present study is focused on the role of lipid rafts in polychlorinated biphenyl (PCB)-induced disruption of occludin and endothelial barrier function. Exposure of human brain endothelial cells to 2,2',4,4',5,5'-hexachlorobiphenyl (PCB153) induced dephosphorylation of threonine residues of occludin and displacement of occludin from detergent-resistant membrane (DRM)/lipid raft fractions within 1h. Moreover, lipid rafts modulated the reduction of occludin level through activation of matrix metalloproteinase 2 (MMP-2) after 24h PCB153 treatment. Inhibition of protein phosphatase 2A (PP2A) activity by okadaic acid or fostriecin markedly protected against PCB153-induced displacement of occludin and increased permeability of endothelial cells. The implication of lipid rafts and PP2A signaling in these processes was further defined by co-immunoprecipitation of occludin with PP2A and caveolin-1, a marker protein of lipid rafts. Indeed, a significant MMP-2 activity was observed in lipid rafts and was increased by exposure to PCB153. The pretreatment of MMP-2 inhibitors protected against PCB153-induced loss of occludin and disruption of lipid raft structure prevented the increase of endothelial permeability. Overall, these results indicate that lipid raft-associated processes, such as PP2A and MMP-2 activation, participate in PCB153-induced disruption of occludin function in brain endothelial barrier. This study contributes to a better understanding of the mechanisms leading to brain endothelial barrier dysfunction in response to exposure to environmental pollutants, such as ortho-substituted PCBs.

  9. Lipid rafts regulate PCB153-induced disruption of occludin and brain endothelial barrier function through protein phosphatase 2A and matrix metalloproteinase-2

    Science.gov (United States)

    Eum, Sung Yong; Jaraki, Dima; András, Ibolya E.; Toborek, Michal

    2015-01-01

    Occludin is an essential integral transmembrane protein regulating tight junction (TJ) integrity in brain endothelial cells. Phosphorylation of occludin is associated with its localization to TJ sites and incorporation into intact TJ assembly. The present study is focused on the role of lipid rafts in polychlorinated biphenyl (PCB)-induced disruption of occludin and endothelial barrier function. Exposure of human brain endothelial cells to 2,2′,4,4′,5,5′-hexachlorobiphenyl (PCB153) induced dephosphorylation of threonine residues of occludin and displacement of occludin from detergent-resistant membrane (DRM)/lipid raft fractions within 1 h. Moreover, lipid rafts modulated the reduction of occludin level through activation of matrix metalloproteinase 2 (MMP-2) after 24 h h PCB153 treatment. Inhibition of protein phosphatase 2A (PP2A) activity by okadaic acid or fostriecin markedly protected against PCB153-induced displacement of occludin and increased permeability of endothelial cells. The implication of lipid rafts and PP2A signaling in these processes was further defined by co-immunoprecipitation of occludin with PP2A and caveolin-1, a marker protein of lipid rafts. Indeed, a significant MMP-2 activity was observed in lipid rafts and was increased by exposure to PCB153. The pretreatment of MMP-2 inhibitors protected against PCB153-induced loss of occludin and disruption of lipid raft structure prevented the increase of endothelial permeability. Overall, these results indicate that lipid raft-associated processes, such as PP2A and MMP-2 activation, participate in PCB153-induced disruption of occludin function in brain endothelial barrier. This study contributes to a better understanding of the mechanisms leading to brain endothelial barrier dysfunction in response to exposure to environmental pollutants, such as ortho-substituted PCBs. PMID:26080028

  10. MTDH mediates trastuzumab resistance in HER2 positive breast cancer by decreasing PTEN expression through an NFκB-dependent pathway

    OpenAIRE

    Du, Cheng; Yi, Xiaomin; Liu, Wenchao; Han, Tao; Liu,Zhaozhe; Ding, Zhenyu; Zheng, Zhendong; PIAO, YING; Yuan, Jianlin; Han, Yaling; Xie, Manjiang; Xie, Xiaodong

    2014-01-01

    Background Trastuzumab resistance is almost inevitable in the management of human epidermal growth factor receptor (HER) 2 positive breast cancer, in which phosphatase and tensin homolog deleted from chromosome 10 (PTEN) loss is implicated. Since metadherin (MTDH) promotes malignant phenotype of breast cancer, we sought to define whether MTDH promotes trastuzumab resistance by decreasing PTEN expression through an NFκB-dependent pathway. Methods The correlations between MTDH and PTEN expressi...

  11. Planarian PTEN homologs regulate stem cells and regeneration through TOR signaling.

    Science.gov (United States)

    Oviedo, Néstor J; Pearson, Bret J; Levin, Michael; Sánchez Alvarado, Alejandro

    2008-01-01

    We have identified two genes, Smed-PTEN-1 and Smed-PTEN-2, capable of regulating stem cell function in the planarian Schmidtea mediterranea. Both genes encode proteins homologous to the mammalian tumor suppressor, phosphatase and tensin homolog deleted on chromosome 10 (PTEN). Inactivation of Smed-PTEN-1 and -2 by RNA interference (RNAi) in planarians disrupts regeneration, and leads to abnormal outgrowths in both cut and uncut animals followed soon after by death (lysis). The resulting phenotype is characterized by hyperproliferation of neoblasts (planarian stem cells), tissue disorganization and a significant accumulation of postmitotic cells with impaired differentiation capacity. Further analyses revealed that rapamycin selectively prevented such accumulation without affecting the normal neoblast proliferation associated with physiological turnover and regeneration. In animals in which PTEN function is abrogated, we also detected a significant increase in the number of cells expressing the planarian Akt gene homolog (Smed-Akt). However, functional abrogation of Smed-Akt in Smed-PTEN RNAi-treated animals does not prevent cell overproliferation and lethality, indicating that functional abrogation of Smed-PTEN is sufficient to induce abnormal outgrowths. Altogether, our data reveal roles for PTEN in the regulation of planarian stem cells that are strikingly conserved to mammalian models. In addition, our results implicate this protein in the control of stem cell maintenance during the regeneration of complex structures in planarians.

  12. Rescue of glandular dysmorphogenesis in PTEN-deficient colorectal cancer epithelium by PPARγ-targeted therapy.

    Science.gov (United States)

    Jagan, I; Fatehullah, A; Deevi, R K; Bingham, V; Campbell, F C

    2013-03-07

    Disruption of glandular architecture associates with poor clinical outcome in high-grade colorectal cancer (CRC). Phosphatase and tensin homolog deleted on chromosome ten (PTEN) regulates morphogenic growth of benign MDCK (Madin Darby Canine Kidney) cells through effects on the Rho-like GTPase cdc42 (cell division cycle 42). This study investigates PTEN-dependent morphogenesis in a CRC model. Stable short hairpin RNA knockdown of PTEN in Caco-2 cells influenced expression or localization of cdc42 guanine nucleotide exchange factors and inhibited cdc42 activation. Parental Caco-2 cells formed regular hollow gland-like structures (glands) with a single central lumen, in three-dimensional (3D) cultures. Conversely, PTEN-deficient Caco-2 ShPTEN cells formed irregular glands with multiple abnormal lumens as well as intra- and/or intercellular vacuoles evocative of the high-grade CRC phenotype. Effects of targeted treatment were investigated. Phosphatidinylinositol 3-kinase (PI3K) modulating treatment did not affect gland morphogenesis but did influence gland number, gland size and/or cell size within glands. As PTEN may be regulated by the nuclear receptor peroxisome proliferator-activated receptor-γ (PPARγ), cultures were treated with the PPARγ ligand rosiglitazone. This treatment enhanced PTEN expression, cdc42 activation and rescued dysmorphogenesis by restoring single lumen formation in Caco-2 ShPTEN glands. Rosiglitazone effects on cdc42 activation and Caco-2 ShPTEN gland development were attenuated by cotreatment with GW9662, a PPARγ antagonist. Taken together, these studies show PTEN-cdc42 regulation of lumen formation in a 3D model of human CRC glandular morphogenesis. Treatment by the PPARγ ligand rosiglitazone, but not PI3K modulators, rescued colorectal glandular dysmorphogenesis of PTEN deficiency.

  13. Hyperactivity of Newborn Pten Knock-out Neurons Results from Increased Excitatory Synaptic Drive

    Science.gov (United States)

    Williams, Michael R.; DeSpenza, Tyrone; Li, Meijie; Gulledge, Allan T.

    2015-01-01

    Developing neurons must regulate morphology, intrinsic excitability, and synaptogenesis to form neural circuits. When these processes go awry, disorders, including autism spectrum disorder (ASD) or epilepsy, may result. The phosphatase Pten is mutated in some patients having ASD and seizures, suggesting that its mutation disrupts neurological function in part through increasing neuronal activity. Supporting this idea, neuronal knock-out of Pten in mice can cause macrocephaly, behavioral changes similar to ASD, and seizures. However, the mechanisms through which excitability is enhanced following Pten depletion are unclear. Previous studies have separately shown that Pten-depleted neurons can drive seizures, receive elevated excitatory synaptic input, and have abnormal dendrites. We therefore tested the hypothesis that developing Pten-depleted neurons are hyperactive due to increased excitatory synaptogenesis using electrophysiology, calcium imaging, morphological analyses, and modeling. This was accomplished by coinjecting retroviruses to either “birthdate” or birthdate and knock-out Pten in granule neurons of the murine neonatal dentate gyrus. We found that Pten knock-out neurons, despite a rapid onset of hypertrophy, were more active in vivo. Pten knock-out neurons fired at more hyperpolarized membrane potentials, displayed greater peak spike rates, and were more sensitive to depolarizing synaptic input. The increased sensitivity of Pten knock-out neurons was due, in part, to a higher density of synapses located more proximal to the soma. We determined that increased synaptic drive was sufficient to drive hypertrophic Pten knock-out neurons beyond their altered action potential threshold. Thus, our work contributes a developmental mechanism for the increased activity of Pten-depleted neurons. PMID:25609613

  14. PTEN, Stem Cells, and Cancer Stem Cells*S⃞

    OpenAIRE

    Hill, Reginald; Wu, Hong

    2009-01-01

    Like normal stem cells, “cancer stem cells” have the capacity for indefinite proliferation and generation of new cancerous tissues through self-renewal and differentiation. Among the major intracellular signaling pathways, WNT, SHH, and NOTCH are known to be important in regulating normal stem cell activities, and their alterations are associated with tumorigenesis. It has become clear recently that PTEN (phosphatase and tensin homologue) is also critical for stem cell...

  15. PTEN alterations of the stromal cells characterise an aggressive subpopulation of pancreatic cancer with enhanced metastatic potential.

    Science.gov (United States)

    Wartenberg, Martin; Centeno, Irene; Haemmig, Stefan; Vassella, Erik; Zlobec, Inti; Galván, José A; Neuenschwander, Maja; Schlup, Cornelia; Gloor, Beat; Lugli, Alessandro; Perren, Aurel; Karamitopoulou, Eva

    2016-09-01

    Neoplastic stroma is believed to influence tumour progression. Here, we examine phosphatase and tensin homolog deleted on chromosome ten (PTEN) status in the tumour microenvironment of pancreatic ductal adenocarcinoma (PDAC) focussing especially at the stromal cells. We asses PTEN at protein, messenger RNA and DNA level using a well-characterised PDAC cohort (n = 117). miR-21, known to target PTEN, is assessed after RNA extraction from different laser-capture-microdissected cell populations, including cancer cells and juxta-tumoural and tumour-remote stroma. PTEN deletion was the most frequent cause of PTEN protein loss in PDAC cells (71%) and correlated with vascular invasion (p = 0.0176) and decreased overall survival (p = 0.0127). Concomitant PTEN protein loss in tumour and juxta-tumoural stroma, found in 21.4% of PDACs, correlated with increased distant metastasis (p = 0.0045). Stromal cells with PTEN protein loss frequently showed PTEN genetic aberrations, including hemizygous PTEN deletion (46.6%) or chromosome 10 monosomy (40%). No alterations were found in the tumour-remote stroma. miR-21 was overexpressed by cancer- and juxta-tumoural stromal cells, in some cases without simultaneous PTEN gene alterations. No PTEN mutations or promoter methylation were detected. We find various mechanisms of PTEN protein loss in the different tumour cell populations, including allelic PTEN deletions, gross chromosomal 10 aberrations and altered miR-21 expression. PTEN deletion is a major cause of PTEN protein loss in PDAC and correlates with aggressive characteristics and worse outcome. PTEN protein loss in juxta-tumoural stromal cells is mostly due to PTEN haplo-insufficiency and characterises a subgroup of PDACs with enhanced metastatic potential. In the tumour microenvironment of the invasive front, PTEN silencing by miR-21 in cancer and surrounding stromal cells acts not only cooperatively but also independently of the genetic aberrations to precipitate PTEN

  16. Lipid rafts regulate PCB153-induced disruption of occludin and brain endothelial barrier function through protein phosphatase 2A and matrix metalloproteinase-2

    Energy Technology Data Exchange (ETDEWEB)

    Eum, Sung Yong, E-mail: seum@miami.edu; Jaraki, Dima; András, Ibolya E.; Toborek, Michal

    2015-09-15

    Occludin is an essential integral transmembrane protein regulating tight junction (TJ) integrity in brain endothelial cells. Phosphorylation of occludin is associated with its localization to TJ sites and incorporation into intact TJ assembly. The present study is focused on the role of lipid rafts in polychlorinated biphenyl (PCB)-induced disruption of occludin and endothelial barrier function. Exposure of human brain endothelial cells to 2,2′,4,4′,5,5′-hexachlorobiphenyl (PCB153) induced dephosphorylation of threonine residues of occludin and displacement of occludin from detergent-resistant membrane (DRM)/lipid raft fractions within 1 h. Moreover, lipid rafts modulated the reduction of occludin level through activation of matrix metalloproteinase 2 (MMP-2) after 24 h PCB153 treatment. Inhibition of protein phosphatase 2A (PP2A) activity by okadaic acid or fostriecin markedly protected against PCB153-induced displacement of occludin and increased permeability of endothelial cells. The implication of lipid rafts and PP2A signaling in these processes was further defined by co-immunoprecipitation of occludin with PP2A and caveolin-1, a marker protein of lipid rafts. Indeed, a significant MMP-2 activity was observed in lipid rafts and was increased by exposure to PCB153. The pretreatment of MMP-2 inhibitors protected against PCB153-induced loss of occludin and disruption of lipid raft structure prevented the increase of endothelial permeability. Overall, these results indicate that lipid raft-associated processes, such as PP2A and MMP-2 activation, participate in PCB153-induced disruption of occludin function in brain endothelial barrier. This study contributes to a better understanding of the mechanisms leading to brain endothelial barrier dysfunction in response to exposure to environmental pollutants, such as ortho-substituted PCBs. - Highlights: • PCB153 disturbed human brain endothelial barrier through disruption of occludin. • Lipid raft-associated PP

  17. A study of the dynamics of PTEN proteins in living cells using in vivo fluorescence correlation spectroscopy

    Science.gov (United States)

    Du, Zhixue; Dong, Chaoqing; Ren, Jicun

    2017-06-01

    PTEN (phosphatase and tensin homolog on chromosome 10) is one of the most important tumor-suppressor proteins, which plays a key role in negative regulation of the PI3K/AKT pathway, and governs many cellular processes including growth, proliferation, survival and migration. The dynamics of PTEN proteins in single living cells is as yet unclear owing to a shortage of suitable in vivo approaches. Here, we report a single-molecule method for in vivo study of the dynamics of PTEN proteins in living cells using fluorescence correlation spectroscopy (FCS). First, we established a monoclonal H1299 stable cell line expressing enhanced green fluorescent protein (EGFP) and PTEN (EGFP-PTEN) fusion proteins; we then developed an in vivo FCS method to study the dynamics of EGFP-PTEN both in the nucleus and the cytoplasm. We investigated the diffusion behaviors of EGFP and EGFP-PTEN in solution, nucleus and cytosol, and observed that the motion of PTEN in living cells was restricted compared with EGFP. Finally, we investigated the protein dynamics in living cells under oxidative stress stimulation and a cellular ATP depletion treatment. Under oxidative stress stimulation, the EGFP-PTEN concentration increased in the nucleus, but slightly decreased in the cytoplasm. The diffusion coefficient and alpha value of EGFP-PTEN reduced significantly both in the nucleus and cytoplasm; the significantly decreased alpha parameter indicates a more restricted Brownian diffusion behavior. Under the cellular ATP depletion treatment, the concentration of EGFP-PTEN remained unchanged in the nucleus and decreased significantly in cytosol. The diffusion coefficient of EGFP-PTEN decreased significantly in cytosol, but showed no significant change in the nucleus; the alpha value decreased significantly in both the nucleus and cytoplasm. These results suggest that the concentration and mobility of PTEN in the nucleus and cytoplasm can be regulated by stimulation methods. Our approach provides a unique

  18. Relationship between PTEN, DNA mismatch repair, and tumor histotype in endometrial carcinoma: retained positive expression of PTEN preferentially identifies sporadic non-endometrioid carcinomas.

    Science.gov (United States)

    Djordjevic, Bojana; Barkoh, Bedia A; Luthra, Rajyalakshmi; Broaddus, Russell R

    2013-10-01

    Loss of PTEN (phosphatase and tensin homolog) expression and microsatellite instability are two of the more common molecular alterations in endometrial carcinoma. From the published literature, it is controversial as to whether there is a relationship between these different molecular mechanisms. Therefore, a cohort of 187 pure endometrioid and non-endometrioid endometrial carcinomas, carefully characterized as to clinical and pathological features, was examined for PTEN sequence abnormalities and the immunohistochemical expression of PTEN and the DNA mismatch repair proteins MLH1, MSH2, MSH6, and PMS2. MLH1 methylation analysis was performed when tumors had loss of MLH1 protein. Mismatch repair protein loss was more frequent in endometrioid carcinomas compared with non-endometrioid carcinomas, a difference primarily attributable to the presence of MLH1 methylation in a greater proportion of endometrioid tumors. Among the non-endometrioid group, mixed endometrioid/non-endometrioid carcinomas were the histotype that most commonly had loss of a mismatch repair protein. In endometrioid tumors, the frequency of PTEN loss measured by immunohistochemistry and mutation did not differ significantly between the mismatch repair protein intact or mismatch repair protein loss groups, suggesting that PTEN loss is independent of mismatch protein repair status in this group. However, in non-endometrioid carcinomas, both intact positive PTEN immunohistochemical expression and PTEN wild type were highly associated with retained positive expression of mismatch repair proteins in the tumor. Relevant to screening endometrial cancers for Lynch Syndrome, an initial PTEN immunohistochemistry determination may be able to replace the use of four mismatch repair immunohistochemical markers in 63% of patients with non-endometrioid endometrial carcinoma. Therefore, PTEN immunohistochemistry, in combination with tumor histotype, is a useful adjunct in the clinical evaluation of endometrial

  19. Downregulation of PTEN at Corneal Wound Sites Accelerates Wound Healing through Increased Cell Migration

    Science.gov (United States)

    Cao, Lin; Graue-Hernandez, Enrique O.; Tran, Vu; Reid, Brian; Pu, Jin; Mannis, Mark J.

    2011-01-01

    Purpose. The PI3K/Akt pathway is required for cell polarization and migration, whereas the phosphatase and tensin homologue deleted on chromosome 10 (PTEN) has inhibitory effects on the PI3K/Akt pathway. The authors therefore hypothesized that wounding would downregulate PTEN and that this downregulation would enhance wound healing. Methods. In human corneal epithelial (HCE) cell monolayer and rat cornea scratch wound models, the authors investigated PTEN and Akt expression using Western blot and immunofluorescence analyses. The effects of PTEN and PI3K inhibitors dipotassium bisperoxo (picolinato) oxovanadate (bpv(pic)) and LY294002 on cell migration and wound closure were investigated using time-lapse imaging. Finally, the authors investigated the effect of PTEN inhibition on wound healing in whole rat eyes. Results. In HCE cell monolayer and rat cornea, PTEN was downregulated at the wound edges within 30 minutes of wounding. The downregulation of PTEN was causal in a simultaneous increase in Akt activation, which was responsible for a significant increase in individual cell migration rate from 8.8 μm/h to 17.3 μm/h. An increased migration rate was maintained for 20 hours. PTEN inhibition significantly enhanced the wound healing rate in the HCE cell monolayer from 10 minutes onward after treatment and reduced the healing time in eye organ culture from 30 to 20 hours. Conclusions. Injury to the corneal epithelium downregulates the expression of PTEN at wound edges, allowing increased PI3K/Akt signaling, thereby contributing to a significant enhancement of cell migration and wound healing. These results suggest that PTEN inhibition may be an effective treatment for corneal injury. PMID:21212174

  20. In Vitro and In Vivo Effects of Tumor Suppressor Gene PTEN on Endometriosis: An Experimental Study

    Science.gov (United States)

    Lv, Juan; Zhu, Qiaoying; Jia, Xuemei; Yu, Ningzhu; Li, Qian

    2016-01-01

    Background Endometriosis can cause dysmenorrhea and infertility. Its pathogenesis has not yet been clarified and its treatment continues to pose enormous challenges. The protein tyrosine phosphatase (PTEN) gene is a tumor suppressor gene. The aim of this study was to investigate the role and significance of PTEN protein in the occurrence, development, and treatment of endometriosis through changes in apoptosis rate, cell cycle, and angiogenesis. Material/Methods PTEN was overexpressed and silenced in lentiviral vectors and inserted into primary endometrial cells. The changes in cell cycle and apoptosis in the different PTEN expression groups were evaluated using flow cytometry. Vessel growth mimicry was observed using 3-dimensional culture. A human-mouse chimeric endometriosis model was constructed using SCID mice. Hematoxylin and eosin staining and immunohistochemistry were used to detect pathological changes in ectopic endometrial tissues and the expression of VEGF protein in a human-mouse chimeric endometriosis mouse model. Results PTEN overexpression significantly increased apoptosis and inhibited the cell cycle compared with the silenced and control groups. Furthermore, cells expressing low PTEN levels were better able to undergo vasculogenic mimicry, and exhibited significantly increased angiogenesis compared to cells overexpressing PTEN. We found that ectopic foci were more easily formed in the endometrial tissue of SCID mice with low PTEN expression, and the VEGF expression in this group was relatively high. Conclusions PTEN inhibits the occurrence and development of endometriosis by regulating angiogenesis and the apoptosis and cell cycle of endometrial cells; therefore, we propose that the PTEN gene can be used to treat endometriosis. PMID:27744455

  1. EGFR- and AKT-mediated reduction in PTEN expression contributes to tyrphostin resistance and is reversed by mTOR inhibition in endometrial cancer cells.

    Science.gov (United States)

    Li, Tian; Yang, Yuebo; Li, Xiaomao; Xu, Chengfang; Meng, Lirong

    2012-02-01

    Loss or mutation of the PTEN (phosphatase and tensin homologue deleted on chromosome 10) gene is associated with resistance to epidermal growth factor receptor (EGFR) inhibitors. However, the mechanism underlying remains elusive. In this study, we aimed to explore whether sensitivity to the EGFR tyrosine kinase inhibitor (TKI) is affected by PTEN status in endometrial cancer cells. PTEN siRNA and the PTEN gene were transfected into HEC-1A and Ishikawa endometrial cancer cells using lentiviral vectors. Cells were treated under various concentrations of RG14620 and rapamycin, which are EGFR and mammalian target of rapamycin (mTOR) inhibitors, respectively. The IC(50) of RG16420 was determined by using the MTT method. Cell apoptosis and the cell cycle were studied, and activation of EGFR, AKT, and p70S6 were detected by Western blot analysis. Loss of PTEN promoted cell proliferation and led to significant increases in the levels of EGFR, phospho-EGFR, AKT, phospho-AKT, and phospho-mTOR proteins. Ishikawa and HEC-1A(PTENkd) cells that displayed loss and inactivation of PTEN function were resistant to RG14620. HEC-1A and Ishikawa(PTEN) cells with intact PTEN were sensitive to RG14620. The combination of two inhibitors was more effective than both monotherapies, particularly in carcinoma cells with PTEN dysfunction. Decreased phospho-EGFR protein expression was observed in all cell lines that were sensitive to RG14620. Decreased phospho-AKT and phospho-p70S6 protein expression was observed in PTEN-intact cells that were sensitive to RG14620. PTEN loss results in resistance to EGFR TKI, which was reversed by PTEN reintroduction or mTOR inhibitor treatment. The combined treatment of EGFR TKI and the mTOR inhibitor provided a synergistic effect by promoting cell death in PTEN-deficient and PTEN-intact endometrial cancer cells, particularly in PTEN-deficient carcinoma cells with up-regulated EGFR activation.

  2. Dysregulation of synaptic plasticity precedes appearance of morphological defects in a Pten conditional knockout mouse model of autism.

    Science.gov (United States)

    Takeuchi, Koichi; Gertner, Michael J; Zhou, Jing; Parada, Luis F; Bennett, Michael V L; Zukin, R Suzanne

    2013-03-19

    The phosphoinositide signaling system is a crucial regulator of neural development, cell survival, and plasticity. Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) negatively regulates phosphatidylinositol 3-kinase signaling and downstream targets. Nse-Cre Pten conditional knockout mice, in which Pten is ablated in granule cells of the dentate gyrus and pyramidal neurons of the hippocampal CA3, but not CA1, recapitulate many of the symptoms of humans with inactivating PTEN mutations, including progressive hypertrophy of the dentate gyrus and deficits in hippocampus-based social and cognitive behaviors. However, the impact of Pten loss on activity-dependent synaptic plasticity in this clinically relevant mouse model of Pten inactivation remains unclear. Here, we show that two phosphatidylinositol 3-kinase- and protein synthesis-dependent forms of synaptic plasticity, theta burst-induced long-term potentiation and metabotropic glutamate receptor (mGluR)-dependent long-term depression, are dysregulated at medial perforant path-to-dentate gyrus synapses of young Nse-Cre Pten conditional knockout mice before the onset of visible morphological abnormalities. In contrast, long-term potentiation and mGluR-dependent long-term depression are normal at CA3-CA1 pyramidal cell synapses at this age. Our results reveal that deletion of Pten in dentate granule cells dysregulates synaptic plasticity, a defect that may underlie abnormal social and cognitive behaviors observed in humans with Pten inactivating mutations and potentially other autism spectrum disorders.

  3. Attenuation of PTEN increases p21 stability and cytosolic localization in kidney cancer cells: a potential mechanism of apoptosis resistance

    Directory of Open Access Journals (Sweden)

    Baksh Shairaz

    2007-02-01

    Full Text Available Abstract Background The PTEN (Phosphatase and Tensin homolog deleted on chromosome Ten tumor suppressor gene is frequently mutated or deleted in a wide variety of solid tumors, and these cancers are generally more aggressive and difficult to treat than those possessing wild type PTEN. While PTEN lies upstream of the phosphoinositide-3 kinase signaling pathway, the mechanisms that mediate its effects on tumor survival remain incompletely understood. Renal cell carcinoma (RCC is associated with frequent treatment failures (~90% in metastatic cases, and these tumors frequently contain PTEN abnormalities. Results Using the ACHN cell line containing wild type PTEN, we generated a stable PTEN knockdown RCC cell line using RNA interference. We then used this PTEN knockdown cell line to show that PTEN attenuation increases resistance to cisplatin-induced apoptosis, a finding associated with increased levels of the cyclin kinase inhibitor p21. Elevated levels of p21 result from stabilization of the protein, and they are dependent on the activities of phosphoinositide-3 kinase and Akt. More specifically, the accumulation of p21 occurs preferentially in the cytosolic compartment, which likely contributes to both cell cycle progression and resistance to apoptosis. Conclusion Since p21 regulates a decision point between repair and apoptosis after DNA damage, our data suggest that p21 plays a key role in mechanisms used by PTEN-deficient tumors to escape chemotherapy. This in turn raises the possibility to use p21 attenuators as chemotherapy sensitizers, an area under active continuing investigation in our laboratories.

  4. Poly-ADP ribosylation of PTEN by tankyrases promotes PTEN degradation and tumor growth

    OpenAIRE

    Li, Nan; Zhang, Yajie; Han, Xin; Liang, Ke; Wang, Jiadong; Feng, Lin; Wang, Wenqi; Songyang, Zhou; Lin, Chunru; Yang, Liuqing; Yu, Yonghao; Chen, Junjie

    2015-01-01

    Li et al. report ADP-ribosylation as a new post-translational modification of the tumor suppressor PTEN. Tankyrases interact with and ribosylate PTEN, which promotes the recognition of PTEN by a PAR-binding E3 ubiquitin ligase, RNF146, leading to PTEN ubiquitination and degradation. Tankyrases were up-regulated and negatively correlated with PTEN expression in human colon carcinomas.

  5. A common variation of the PTEN gene is associated with peripheral insulin resistance

    DEFF Research Database (Denmark)

    Grinder-Hansen, L; Ribel-Madsen, R; Wojtaszewski, Jørgen

    2016-01-01

    . RESULTS: The minor G allele of PTEN rs11202614 was associated with elevated fasting plasma insulin levels and a decreased peripheral glucose disposal rate, but not with the hepatic insulin resistance index or insulin secretion measured as the first-phase insulin response and disposition index. The single...... nucleotide polymorphism was not associated with either PI3K or Akt activities. CONCLUSION: A common PTEN variation is associated with peripheral insulin resistance and subsequent risk of developing T2D. However, the association with insulin resistance is not explained by decreased proximal insulin signalling......AIM: Phosphatase and tensin homologue (PTEN) reduces insulin sensitivity by inhibiting the phosphatidylinositol 3-kinase (PI3K)/v-akt murine thymoma viral oncogene homologue (Akt) pathway. This study investigated how a common single nucleotide polymorphism near PTEN, previously associated...

  6. Kaempferol Promotes Apoptosis in Human Bladder Cancer Cells by Inducing the Tumor Suppressor, PTEN

    Directory of Open Access Journals (Sweden)

    Liqun Zhou

    2013-10-01

    Full Text Available Kaempferol (Kae, a natural flavonoid, is widely distributed in fruits and vegetables. Previous studies have identified Kae as a possible cancer preventive and therapeutic agent. We found Kae to exhibit potent antiproliferation and anti-migration effects in human bladder cancer EJ cells. Kaempferol robustly induced apoptosis in EJ cells in a dose-dependent manner, as evidenced by increased cleavage of caspase-3. Furthermore, we found Kae-induced apoptosis in EJ cells to be associated with phosphatase and the tensin homolog deleted on the chromosome 10 (PTEN/PI3K/Akt pathway. Kae significantly increased PTEN and decreased Akt phosphorylation. Kae-induced apoptosis was partially attenuated in PTEN-knockdown cells. Our findings indicate that Kae could be an alternative medicine for bladder cancer, based on a PTEN activation mechanism.

  7. Long-term consequences of conditional genetic deletion of PTEN in the sensorimotor cortex of neonatal mice.

    Science.gov (United States)

    Gutilla, Erin A; Buyukozturk, Melda M; Steward, Oswald

    2016-05-01

    Targeted deletion of the phosphatase and tensin homolog on chromosome ten (PTEN) gene in the sensorimotor cortex of neonatal mice enables robust regeneration of corticospinal tract (CST) axons following spinal cord injury as adults. Here, we assess the consequences of long-term conditional genetic PTEN deletion on cortical structure and neuronal morphology and screen for neuropathology. Mice with a LoxP-flanked exon 5 of the PTEN gene (PTENf/f mice) received AAV-Cre injections into the sensorimotor cortex at postnatal day 1 (P1) and were allowed to survive for up to 18months. As adults, mice were assessed for exploratory activity (open field), and motor coordination using the Rotarod®. Some mice received injections of Fluorogold into the spinal cord to retrogradely label the cells of origin of the CST. Brains were prepared for neurohistology and immunostained for PTEN and phospho-S6, which is a downstream marker of mammalian target of rapamycin (mTOR) activation. Immunostaining revealed a focal area of PTEN deletion affecting neurons in all cortical layers, although in some cases PTEN expression was maintained in many small-medium sized neurons in layers III-IV. Neurons lacking PTEN were robustly stained for pS6. Cortical thickness was significantly increased and cortical lamination was disrupted in the area of PTEN deletion. PTEN-negative layer V neurons that give rise to the CST, identified by retrograde labeling, were larger than neurons with maintained PTEN expression, and the relative area occupied by neuropil vs. cell bodies was increased. There was no evidence of tumor formation or other neuropathology. Mice with PTEN deletion exhibited open field activity comparable to controls and there was a trend for impaired Rotarod performance (not statistically significant). Our findings indicate that early postnatal genetic deletion of PTEN that is sufficient to enable axon regeneration by adult neurons causes neuronal hypertrophy but no other detectable

  8. Deletion of PTEN Produces Deficits in Conditioned Fear and Increases Fragile X Mental Retardation Protein

    Science.gov (United States)

    Lugo, Joaquin N.; Smith, Gregory D.; Morrison, Jessica B.; White, Jessika

    2013-01-01

    The phosphatase and tensin homolog detected on chromosome 10 (PTEN) gene product modulates activation of the phosphatidylinositol 3-kinase (PI3K)/AKT pathway. The PI3K pathway has been found to be involved in the regulation of the fragile X mental retardation protein, which is important for long-term depression and in the formation of new…

  9. The phosphatase and tensin homolog regulates epidermal growth factor receptor (EGFR) inhibitor response by targeting EGFR for degradation

    OpenAIRE

    Vivanco, Igor; Rohle, Daniel; Versele, Matthias; Iwanami, Akio; Kuga, Daisuke; Oldrini, Barbara; Tanaka, Kazuhiro; Dang, Julie; Kubek, Sara; Palaskas, Nicolaos; Hsueh, Teli; Evans, Michael; Mulholland, David; Wolle, Daniel; Rajasekaran, Sigrid

    2010-01-01

    The phosphatase and tensin homolog (PTEN) is a tumor suppressor that is inactivated in many human cancers. PTEN loss has been associated with resistance to inhibitors of the epidermal growth factor receptor (EGFR), but the molecular basis of this resistance is unclear. It is believed that unopposed phosphatidylinositol-3-kinase (PI3K) activation through multiple receptor tyrosine kinases (RTKs) can relieve PTEN-deficient cancers from their “dependence” on EGFR or any other single RTK for surv...

  10. Phosphatase and tensin homolog deleted on chromosome 10 contributes to phenotype transformation of fibroblasts in idiopathic pulmonary fibrosis via multiple pathways

    Science.gov (United States)

    Geng, Jing; Huang, Xiaoxi; Li, Ying; Xu, Xuefeng; Li, Shuhong; Jiang, Dingyuan; Liu, Zheng

    2015-01-01

    Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal disease and considered as a cancer-like disease. The phosphatase and tensin homologue deleted on chromosome 10 (PTEN) tumor suppressor has drawn attention in the pathogenesis of IPF. However, the role of PTEN in phenotypic transformation of lung fibroblasts, particularly in the migratory and invasive phenotype, is still elusive. Our data showed that PTEN expression was markedly reduced in both fibroblasts and myofibroblasts from IPF patients. Furthermore, loss of PTEN led to the transformation of normal fibroblasts to myofibroblasts and increased proliferation, apoptosis resistance, and migration/invasion activities. PTEN deficiency upregulated hyaluronan synthase 2 expression and thereby enhanced the invasion ability of fibroblasts. Cross-talk between PTEN and the transforming growth factor β1 (TGF-β1) pathway and PTEN reduction by hypoxia were observed. These findings suggest that PTEN is implicated in multiple pathways and plays a crucial role in the pathogenesis of IPF. PMID:26264443

  11. Protein phosphatase 5 mediates lipid metabolism through reciprocal control of glucocorticoid receptor and peroxisome proliferator-activated receptor-γ (PPARγ).

    Science.gov (United States)

    Hinds, Terry D; Stechschulte, Lance A; Cash, Harrison A; Whisler, Donald; Banerjee, Ananya; Yong, Weidong; Khuder, Saja S; Kaw, Meenakshi K; Shou, Weinian; Najjar, Sonia M; Sanchez, Edwin R

    2011-12-16

    Glucocorticoid receptor-α (GRα) and peroxisome proliferator-activated receptor-γ (PPARγ) regulate adipogenesis by controlling the balance between lipolysis and lipogenesis. Here, we show that protein phosphatase 5 (PP5), a nuclear receptor co-chaperone, reciprocally modulates the lipometabolic activities of GRα and PPARγ. Wild-type and PP5-deficient (KO) mouse embryonic fibroblast cells were used to show binding of PP5 to both GRα and PPARγ. In response to adipogenic stimuli, PP5-KO mouse embryonic fibroblast cells showed almost no lipid accumulation with reduced expression of adipogenic markers (aP2, CD36, and perilipin) and low fatty-acid synthase enzymatic activity. This was completely reversed following reintroduction of PP5. Loss of PP5 increased phosphorylation of GRα at serines 212 and 234 and elevated dexamethasone-induced activity at prolipolytic genes. In contrast, PPARγ in PP5-KO cells was hyperphosphorylated at serine 112 but had reduced rosiglitazone-induced activity at lipogenic genes. Expression of the S112A mutant rescued PPARγ transcriptional activity and lipid accumulation in PP5-KO cells pointing to Ser-112 as an important residue of PP5 action. This work identifies PP5 as a fulcrum point in nuclear receptor control of the lipolysis/lipogenesis equilibrium and as a potential target in the treatment of obesity.

  12. Interaction of E-cadherin and PTEN regulates morphogenesis and growth arrest in human mammary epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Fournier, Marcia V.; Fata, Jimmie E.; Martin, Katherine J.; Yaswen, Paul; Bissell, Mina J.

    2009-06-03

    PTEN is a dual function phosphatase with tumor suppressor function compromised in a wide spectrum of cancers. Because tissue polarity and architecture are crucial modulators of normal and malignant behavior, we postulated that PTEN may play a role in maintenance of tissue integrity. We used two non-malignant human mammary epithelial cell lines (HMECs) that form polarized, growth-arrested structures (acini) when cultured in 3-dimensional laminin-rich extracellular matrix gels (3D lrECM). As acini begin to form, PTEN accumulates in both the cytoplasm, and at cell-cell contacts where it colocalizes with E-cadherin/{beta}-catenin complex. Reduction of PTEN levels by shRNA in lrECM prevents formation of organized breast acini and disrupts growth arrest. Importantly, disruption of acinar polarity and cell-cell contact by E-cadherin function-blocking antibodies reduces endogenous PTEN protein levels and inhibits its accumulation at cell-cell contacts. Conversely, in SKBR3 breast cancer cells lacking endogenous E-cadherin expression, exogenous introduction of E-cadherin gene causes induction of PTEN expression and its accumulation at sites of cell interactions. These studies provide evidence that E-cadherin regulates both the PTEN protein levels and its recruitment to cell-cell junctions in 3D lrECM indicating a dynamic reciprocity between architectural integrity and the levels and localization of PTEN. This interaction thus appears to be a critical integrator of proliferative and morphogenetic signaling in breast epithelial cells.

  13. PTEN and p53 cross-regulation induced by soy isoflavone genistein promotes mammary epithelial cell cycle arrest and lobuloalveolar differentiation.

    Science.gov (United States)

    Rahal, Omar M; Simmen, Rosalia C M

    2010-08-01

    The tumor suppressors phosphatase and tensin homologue deleted on chromosome ten (PTEN) and p53 are closely related to the pathogenesis of breast cancer, yet pathway-specific mechanisms underlying their participation in mediating the protective actions of dietary bioactive components on breast cancer risk are poorly understood. We recently showed that dietary exposure to the soy isoflavone genistein (GEN) induced PTEN expression in mammary epithelial cells in vivo and in vitro, consistent with the breast cancer preventive effects of soy food consumption. Here, we evaluated PTEN and p53 functional interactions in the nuclear compartment of mammary epithelial cells as a mechanism for mammary tumor protection by GEN. Using the non-tumorigenic human mammary epithelial cells MCF10-A, we demonstrate that GEN increased PTEN expression and nuclear localization. We show that increased nuclear PTEN levels initiated an autoregulatory loop involving PTEN-dependent increases in p53 nuclear localization, PTEN-p53 physical association, PTEN-p53 co-recruitment to the PTEN promoter region and p53 transactivation of PTEN promoter activity. The PTEN-p53 cross talk induced by GEN resulted in increased cell cycle arrest; decreased pro-proliferative cyclin D1 and pleiotrophin gene expression and the early formation of mammary acini, indicative of GEN promotion of lobuloalveolar differentiation. Our findings provide support to GEN-induced PTEN as both a target and regulator of p53 action and offer a mechanistic basis for PTEN pathway activation to underlie the antitumor properties of dietary factors, with important implications for reducing breast cancer risk.

  14. Relationsip between PTEN and VEGF Expression and Clinicopathological Characteristics in HCC

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    To investigate the expressions and significance of the tumor suppressor gene phosphatase and tensin homlog deleted on chromosome ten protein (PTEN) and vascular endothelial growth factor (VEGF) in hepatocellular carcinoma (HCC), and to analyze the relationship between their expressions and the tumor's invasion and their pericarcinomatous tissues, the correlation of their expressions with the tumor's clinicopathological characteristics and invasion potential were studied. Our study showed that the expression level of PTEN in HCC was remarkably lower than that in pericarcinomatous liver tissues, while the expressions of both VEGF and MVD were higher than that in pericarcinomatous liver tissues. Correlation analysis revealed that the expression of PTEN was negatively related to the progression of the pathological differentiation and invasion of tumor, whereas the expressions of VEGF and MVD were positively related. Moreover, there was a negative relationship between the expression of PTEN and the expressions of VEGF and MVD, and a positive one between VEGF and MVD. The expressions of PTEN and VEGF may reveal the degree of differentiation and the invasive potential of HCC tissues. The mechanism by which the lack of PTEN expression probably induces abnormal hyperexpression of VEGF may play an important role in the invasion and metastasis of HCC.

  15. Regulation of mammary stem/progenitor cells by PTEN/Akt/beta-catenin signaling.

    Directory of Open Access Journals (Sweden)

    Hasan Korkaya

    2009-06-01

    Full Text Available Recent evidence suggests that many malignancies, including breast cancer, are driven by a cellular subcomponent that displays stem cell-like properties. The protein phosphatase and tensin homolog (PTEN is inactivated in a wide range of human cancers, an alteration that is associated with a poor prognosis. Because PTEN has been reported to play a role in the maintenance of embryonic and tissue-specific stem cells, we investigated the role of the PTEN/Akt pathway in the regulation of normal and malignant mammary stem/progenitor cell populations. We demonstrate that activation of this pathway, via PTEN knockdown, enriches for normal and malignant human mammary stem/progenitor cells in vitro and in vivo. Knockdown of PTEN in normal human mammary epithelial cells enriches for the stem/progenitor cell compartment, generating atypical hyperplastic lesions in humanized NOD/SCID mice. Akt-driven stem/progenitor cell enrichment is mediated by activation of the Wnt/beta-catenin pathway through the phosphorylation of GSK3-beta. In contrast to chemotherapy, the Akt inhibitor perifosine is able to target the tumorigenic cell population in breast tumor xenografts. These studies demonstrate an important role for the PTEN/PI3-K/Akt/beta-catenin pathway in the regulation of normal and malignant stem/progenitor cell populations and suggest that agents that inhibit this pathway are able to effectively target tumorigenic breast cancer cells.

  16. Glioma cell VEGFR-2 confers resistance to chemotherapeutic and antiangiogenic treatments in PTEN-deficient glioblastoma.

    Science.gov (United States)

    Kessler, Tobias; Sahm, Felix; Blaes, Jonas; Osswald, Matthias; Rübmann, Petra; Milford, David; Urban, Severino; Jestaedt, Leonie; Heiland, Sabine; Bendszus, Martin; Hertenstein, Anne; Pfenning, Philipp-Niclas; Ruiz de Almodóvar, Carmen; Wick, Antje; Winkler, Frank; von Deimling, Andreas; Platten, Michael; Wick, Wolfgang; Weiler, Markus

    2015-10-13

    Loss of the tumor suppressor phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a prerequisite for tumor cell-specific expression of vascular endothelial growth factor receptor (VEGFR)-2 in glioblastoma defining a subgroup prone to develop evasive resistance towards antiangiogenic treatments. Immunohistochemical analysis of human tumor tissues showed VEGFR-2 expression in glioma cells in 19% of specimens examined, mainly in the infiltration zone. Glioma cell VEGFR-2 positivity was restricted to PTEN-deficient tumor specimens. PTEN overexpression reduced VEGFR-2 expression in vitro, as well as knock-down of raptor or rictor. Genetic interference with VEGFR-2 revealed proproliferative, antiinvasive and chemoprotective functions for VEGFR-2 in glioma cells. VEGFR-2-dependent cellular effects were concomitant with activation of 'kappa-light-chain-enhancer' of activated B-cells, protein kinase B, and N-myc downstream regulated gene 1. Two-photon in vivo microscopy revealed that expression of VEGFR-2 in glioma cells hampers antiangiogenesis. Bevacizumab induces a proinvasive response in VEGFR-2-positive glioma cells. Patients with PTEN-negative glioblastomas had a shorter survival after initiation of bevacizumab therapy compared with PTEN-positive glioblastomas. Conclusively, expression of VEGFR-2 in glioma cells indicates an aggressive glioblastoma subgroup developing early resistance to temozolomide or bevacizumab. Loss of PTEN may serve as a biomarker identifying those tumors upfront by routine neuropathological methods.

  17. Myeloid PTEN deficiency protects livers from ischemia reperfusion injury by facilitating M2 macrophage differentiation.

    Science.gov (United States)

    Yue, Shi; Rao, Jianhua; Zhu, Jianjun; Busuttil, Ronald W; Kupiec-Weglinski, Jerzy W; Lu, Ling; Wang, Xuehao; Zhai, Yuan

    2014-06-01

    Although the role of phosphatase and tensin homolog deleted on chromosome 10 (PTEN) in regulating cell proliferation is well established, its function in immune responses remains to be fully appreciated. In the current study, we analyzed myeloid-specific PTEN function in regulating tissue inflammatory immune response in a murine liver partial warm ischemia model. Myeloid-specific PTEN knockout (KO) resulted in liver protection from ischemia reperfusion injury (IRI) by deviating the local innate immune response against ischemia reperfusion toward the regulatory type: expression of proinflammatory genes was selectively decreased and anti-inflammatory IL-10 was simultaneously increased in ischemia reperfusion livers of PTEN KO mice compared with those of wild-type (WT) mice. PI3K inhibitor and IL-10-neutralizing Abs, but not exogenous LPS, recreated liver IRI in these KO mice. At the cellular level, Kupffer cells and peritoneal macrophages isolated from KO mice expressed higher levels of M2 markers and produced lower TNF-α and higher IL-10 in response to TLR ligands than did their WT counterparts. They had enhanced Stat3- and Stat6-signaling pathway activation, but diminished Stat1-signaling pathway activation, in response to TLR4 stimulation. Inactivation of Kupffer cells by gadolinium chloride enhanced proinflammatory immune activation and increased IRI in livers of myeloid PTEN KO mice. Thus, myeloid PTEN deficiency protects livers from IRI by facilitating M2 macrophage differentiation.

  18. Metformin inhibits inflammatory response via AMPK-PTEN pathway in vascular smooth muscle cells

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sun Ae [Department of Pharmacology, Aging-Associated Vascular Disease Research Center, College of Medicine, Yeungnam University, Daegu 705-717 (Korea, Republic of); Choi, Hyoung Chul, E-mail: hcchoi@med.yu.ac.kr [Department of Pharmacology, Aging-Associated Vascular Disease Research Center, College of Medicine, Yeungnam University, Daegu 705-717 (Korea, Republic of)

    2012-09-07

    Highlights: Black-Right-Pointing-Pointer PTEN was induced by metformin and inhibited by compound C and AMPK siRNA. Black-Right-Pointing-Pointer Metformin suppressed TNF-{alpha}-induced COX-2 and iNOS mRNA expression. Black-Right-Pointing-Pointer Compound C and bpv (pic) increased iNOS and COX-2 protein expression. Black-Right-Pointing-Pointer NF-{kappa}B activation was restored by inhibiting AMPK and PTEN. Black-Right-Pointing-Pointer AMPK and PTEN regulated TNF-{alpha}-induced ROS production in VSMCs. -- Abstract: Atherosclerosis is a chronic inflammation of the coronary arteries. Vascular smooth muscle cells (VSMCs) stimulated by cytokines and chemokines accelerate the inflammatory response and migrate to the injured endothelium during the progression of atherosclerosis. Activation of AMP activated protein kinase (AMPK), a key sensor maintaining metabolic homeostasis, suppresses the inflammatory response. However, how AMPK regulates the inflammatory response is poorly understood. To identify the mechanism of this response, we focused on phosphatase and tensin homolog (PTEN), which is a negative regulator of inflammation. We investigated that activation of AMPK-induced PTEN expression and suppression of the inflammatory response through the AMPK-PTEN pathway in VSMCs. We treated with the well-known AMPK activator metformin to induce PTEN expression. PTEN was induced by metformin (2 mM) and inhibited by compound C (10 {mu}M) and AMPK siRNA. Tumor necrosis factor-alpha (TNF-{alpha}) was used to induce inflammation. The inflammatory response was confirmed by cyclooxygenase (COX)-2, inducible nitric oxide synthase (iNOS) expression, and activation of nuclear factor (NF)-{kappa}B. Metformin suppressed COX-2 and iNOS mRNA and protein expression dose dependently. Treatment with compound C and bpv (pic) in the presence of metformin, iNOS and COX-2 protein expression increased. NF-{kappa}B activation decreased in response to metformin and was restored by inhibiting AMPK

  19. Pten Regulates Retinal Amacrine Cell Number by Modulating Akt, Tgfβ, and Erk Signaling.

    Science.gov (United States)

    Tachibana, Nobuhiko; Cantrup, Robert; Dixit, Rajiv; Touahri, Yacine; Kaushik, Gaurav; Zinyk, Dawn; Daftarian, Narsis; Biernaskie, Jeff; McFarlane, Sarah; Schuurmans, Carol

    2016-09-07

    All tissues are genetically programmed to acquire an optimal size that is defined by total cell number and individual cellular dimensions. The retina contains stereotyped proportions of one glial and six neuronal cell types that are generated in overlapping waves. How multipotent retinal progenitors know when to switch from making one cell type to the next so that appropriate numbers of each cell type are generated is poorly understood. Pten is a phosphatase that controls progenitor cell proliferation and differentiation in several lineages. Here, using a conditional loss-of-function strategy, we found that Pten regulates retinal cell division and is required to produce the full complement of rod photoreceptors and amacrine cells in mouse. We focused on amacrine cell number control, identifying three downstream Pten effector pathways. First, phosphoinositide 3-kinase/Akt signaling is hyperactivated in Pten conditional knock-out (cKO) retinas, and misexpression of constitutively active Akt (Akt-CA) in retinal explants phenocopies the reduction in amacrine cell production observed in Pten cKOs. Second, Akt-CA activates Tgfβ signaling in retinal explants, which is a negative feedback pathway for amacrine cell production. Accordingly, Tgfβ signaling is elevated in Pten cKO retinas, and epistatic analyses placed Pten downstream of TgfβRII in amacrine cell number control. Finally, Pten regulates Raf/Mek/Erk signaling levels to promote the differentiation of all amacrine cell subtypes, which are each reduced in number in Pten cKOs. Pten is thus a positive regulator of amacrine cell production, acting via multiple downstream pathways, highlighting its diverse actions as a mediator of cell number control. Despite the importance of size for optimal organ function, how individual cell types are generated in correct proportions is poorly understood. There are several ways to control cell number, including readouts of organ function (e.g., secreted hormones reach functional

  20. Phosphatase and tensin homologue deleted on chromosome 10

    Directory of Open Access Journals (Sweden)

    Imran Haruna Abdulkareem

    2013-01-01

    Full Text Available Phosphatase and tensin homologue deleted on chromosome 10 (PTEN is a tumor suppressor gene deleted or mutated in many human cancers such as glioblastoma, spinal tumors, prostate, bladder, adrenals, thyroid, breast, endometrium, and colon cancers. They result from loss of heterozygosity (LOH for the PTEN gene on chromosome 10q23. Previous studies reported that various drugs, chemicals, and foods can up-regulate PTEN mRNA and protein expression in different cell lines, and they may be useful in the future prevention and/or treatment of these cancers. PTEN has also been observed to have prognostic significance and is gradually being accepted as an independent prognostic factor. This will help in monitoring disease progression and/or recurrence, with a view to improving treatment outcomes and reducing the associated morbidity and mortality from these cancers. Neprilysin (NEP is a zinc-dependent metallopeptidase that cleaves and inactivates some biologically active peptides thus switching off signal transduction at the cell surface. Decreased NEP expression in many cancers has been reported. NEP can form a complex with PTEN and enhance PTEN recruitment to the plasma membrane as well as stabilize its phosphatase activity. MicroRNA-21 (miR-21 post-transcriptionally down-regulates the expression of PTEN and stimulates growth and invasion in non-small cell lung cancer (NSCLC (lung Ca, suggesting that this may be a potential therapeutic target in the future treatment of NSCLC. PTEN is a tumor suppressor gene associated with many human cancers. This has diagnostic, therapeutic, and prognostic significance in the management of many human cancers, and may be a target for new drug development in the future.

  1. MicroRNA-21 regulates hTERT via PTEN in hypertrophic scar fibroblasts.

    Directory of Open Access Journals (Sweden)

    Hua-Yu Zhu

    Full Text Available BACKGROUND: As an important oncogenic miRNA, microRNA-21 (miR-21 is associated with various malignant diseases. However, the precise biological function of miR-21 and its molecular mechanism in hypertrophic scar fibroblast cells has not been fully elucidated. METHODOLOGY/PRINCIPAL FINDINGS: Quantitative Real-Time PCR (qRT-PCR analysis revealed significant upregulation of miR-21 in hypertrophic scar fibroblast cells compared with that in normal skin fibroblast cells. The effects of miR-21 were then assessed in MTT and apoptosis assays through in vitro transfection with a miR-21 mimic or inhibitor. Next, PTEN (phosphatase and tensin homologue deleted on chromosome ten was identified as a target gene of miR-21 in hypertrophic scar fibroblast cells. Furthermore, Western-blot and qRT-PCR analyses revealed that miR-21 increased the expression of human telomerase reverse transcriptase (hTERT via the PTEN/PI3K/AKT pathway. Introduction of PTEN cDNA led to a remarkable depletion of hTERT and PI3K/AKT at the protein level as well as inhibition of miR-21-induced proliferation. In addition, Western-blot and qRT-PCR analyses confirmed that hTERT was the downstream target of PTEN. Finally, miR-21 and PTEN RNA expression levels in hypertrophic scar tissue samples were examined. Immunohistochemistry assays revealed an inverse correlation between PTEN and hTERT levels in high miR-21 RNA expressing-hypertrophic scar tissues. CONCLUSIONS/SIGNIFICANCE: These data indicate that miR-21 regulates hTERT expression via the PTEN/PI3K/AKT signaling pathway by directly targeting PTEN, therefore controlling hypertrophic scar fibroblast cell growth. MiR-21 may be a potential novel molecular target for the treatment of hypertrophic scarring.

  2. Connexin43 recruits PTEN and Csk to inhibit c-Src activity in glioma cells and astrocytes

    Science.gov (United States)

    González-Sánchez, Ana; Jaraíz-Rodríguez, Myriam; Domínguez-Prieto, Marta; Herrero-González, Sandra; Medina, José M.; Tabernero, Arantxa

    2016-01-01

    Connexin43 (Cx43), the major protein forming gap junctions in astrocytes, is reduced in high-grade gliomas, where its ectopic expression exerts important effects, including the inhibition of the proto-oncogene tyrosine-protein kinase Src (c-Src). In this work we aimed to investigate the mechanism responsible for this effect. The inhibition of c-Src requires phosphorylation at tyrosine 527 mediated by C-terminal Src kinase (Csk) and dephosphorylation at tyrosine 416 mediated by phosphatases, such as phosphatase and tensin homolog (PTEN). Our results showed that the antiproliferative effect of Cx43 is reduced when Csk and PTEN are silenced in glioma cells, suggesting the involvement of both enzymes. Confocal microscopy and immunoprecipitation assays confirmed that Cx43, in addition to c-Src, binds to PTEN and Csk in glioma cells transfected with Cx43 and in astrocytes. Pull-down assays showed that region 266–283 in Cx43 is sufficient to recruit c-Src, PTEN and Csk and to inhibit the oncogenic activity of c-Src. As a result of c-Src inhibition, PTEN was increased with subsequent inactivation of Akt and reduction of proliferation of human glioblastoma stem cells. We conclude that the recruitment of Csk and PTEN to the region between residues 266 and 283 within the C-terminus of Cx43 leads to c-Src inhibition. PMID:27391443

  3. BMP-2 up-regulates PTEN expression and induces apoptosis of pulmonary artery smooth muscle cells under hypoxia.

    Directory of Open Access Journals (Sweden)

    Weifeng Pi

    Full Text Available AIM: To investigate the role of bone morphogenetic protein 2 (BMP-2 in regulation of phosphatase and tensin homologue deleted on chromosome ten (PTEN and apoptosis of pulmonary artery smooth muscle cells (PASMCs under hypoxia. METHODS: Normal human PASMCs were cultured in growth medium (GM and treated with BMP-2 from 5-80 ng/ml under hypoxia (5% CO(2+94% N(2+1% O(2 for 72 hours. Gene expression of PTEN, AKT-1 and AKT-2 were determined by quantitative RT-PCR (QRT-PCR. Protein expression levels of PTEN, AKT and phosph-AKT (pAKT were determined. Apoptosis of PASMCs were determined by measuring activities of caspases-3, -8 and -9. siRNA-smad-4, bpV(HOpic (PTEN inhibitor and GW9662 (PPARγ antagonist were used to determine the signalling pathways. RESULTS: Proliferation of PASMCs showed dose dependence of BMP-2, the lowest proliferation rate was achieved at 60 ng/ml concentration under hypoxia (82.2±2.8%. BMP-2 increased PTEN gene expression level, while AKT-1 and AKT-2 did not change. Consistently, the PTEN protein expression also showed dose dependence of BMP-2. AKT activity significantly reduced in BMP-2 treated PASMCs. Increased activities of caspase-3, -8 and -9 of PASMCs were found after cultured with BMP-2. PTEN expression remained unchanged when Smad-4 expression was inhibited by siRNA-Smad-4. bpV(HOpic and GW9662 (PPARγ inhibitor inhibited PTEN protein expression and recovered PASMCs proliferation rate. CONCLUSION: BMP-2 increased PTEN expression under hypoxia in a dose dependent pattern. BMP-2 reduced AKT activity and increased caspase activity of PASMCs under hypoxia. The increased PTEN expression may be mediated through PPARγ signalling pathway, instead of BMP/Smad signalling pathway.

  4. PTEN enhances G2/M arrest in etoposide-treated MCF‑7 cells through activation of the ATM pathway.

    Science.gov (United States)

    Zhang, Ruopeng; Zhu, Li; Zhang, Lirong; Xu, Anli; Li, Zhengwei; Xu, Yijuan; He, Pei; Wu, Maoqing; Wei, Fengxiang; Wang, Chenhong

    2016-05-01

    As an effective tumor suppressor, phosphatase and tensin homolog (PTEN) has attracted the increased attention of scientists. Recent studies have shown that PTEN plays unique roles in the DNA damage response (DDR) and can interact with the Chk1 pathway. However, little is known about how PTEN contributes to DDR through the ATM-Chk2 pathway. It is well-known that etoposide induces G2/M arrest in a variety of cell lines, including MCF-7 cells. The DNA damage-induced G2/M arrest results from the activation of protein kinase ataxia telangiectasia mutated (ATM), followed by the activation of Chk2 that subsequently inactivates CDC25C, resulting in G2/M arrest. In the present study, we assessed the contribution of PTEN to the etoposide-induced G2/M cell cycle arrest. PTEN was knocked down in MCF-7 cells by specific shRNA, and the effects of PTEN on the ATM-Chk2 pathway were investigated through various approaches. The results showed that knockdown of PTEN strongly antagonized ATM activation in response to etoposide treatment, and thereby reduced the phosphorylation level of ATM substrates, including H2AX, P53 and Chk2. Furthermore, depletion of PTEN reduced the etoposide-induced phosphorylation of CDC25C and strikingly compromised etoposide-induced G2/M arrest in the MCF-7 cells. Altogether, we demonstrated that PTEN plays a unique role in etoposide-induced G2/M arrest by facilitating the activation of the ATM pathway, and PTEN was required for the proper activation of checkpoints in response to DNA damage in MCF-7 cells.

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

    Science.gov (United States)

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

    2013-11-01

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

  6. Lipid signaling in plants

    NARCIS (Netherlands)

    Munnik, T.

    2010-01-01

    This book highlights the current status of plant lipid signaling. Written by leading researchers in the field, the chapters include detailed information on the measurement, regulation and function of phospholipases, lipid kinases, lipid phosphatases, inositolpolyphosphates, polyphosphoinositides, ph

  7. Overexpression of LRIG1 regulates PTEN via MAPK/MEK signaling pathway in esophageal squamous cell carcinoma

    Science.gov (United States)

    Jiang, Xiaofang; Li, Huiwu

    2016-01-01

    The present study aimed to evaluate the role of leucine-rich repeats and immunoglobulin-like domain protein 1 (LRIG1) in the regulation of phosphatase and tensin homolog (PTEN) expression in esophageal carcinogenesis. LRIG1 was overexpressed in esophageal squamous cell carcinoma (ESCC) cell lines, and the effect of LRIG1 overexpression on the mRNA and protein expression levels of PTEN was evaluated by reverse transcription-quantitative polymerase chain reaction and western blotting. Furthermore, the effects of LRIG1 overexpression on the cell cycle distribution and apoptosis of ESCC cells were examined by flow cytometry. Various cell signaling pathway inhibitors were used to assess the effects of LRIG1 on downstream signaling in ESCC cell lines. In addition, the association between LRIG1 and PTEN expression was examined in 48 samples from patients with ESCC. LRIG1 overexpression was demonstrated to downregulate PTEN expression in ESCC cell lines, and promote their proliferation and inhibit apoptosis. In addition, LRIG1-mediated suppression of PTEN expression was inhibited by the U0126 inhibitor, which suggests that LRIG1 may inhibit the activation of PTEN signaling molecules by triggering the mitogen-activated protein kinase (MAPK)/MAPK kinase 1 (MEK) signaling pathway. In conclusion, the present study demonstrated that overexpression of LRIG1 significantly and adversely affected the survival of ESCC cells, and that the MAPK/MEK signaling pathway may be responsible for the repression of PTEN expression and function. PMID:27698691

  8. 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

    doxorubicin and paclitaxel. Raf induced the expression of the drug pump Mdr-1 (a.k.a., Pgp) and the Bcl-2 anti-apoptotic protein. Raf did not appear to induce drug resistance by altering p53/p21Cip-1 expression, whose expression is often linked to regulation of cell cycle progression and drug resistance. Deregulation of the PI3K/PTEN/Akt pathway was associated with resistance to doxorubicin and 4-hydroxyl tamoxifen, a chemotherapeutic drug and estrogen receptor antagonist used in breast cancer therapy. In contrast to the drug-resistant breast cancer cells obtained after overexpression of activated Raf, cells expressing activated Akt displayed altered (decreased) levels of p53/p21Cip-1. Deregulated expression of the central phosphatase in the PI3K/PTEN/Akt pathway led to breast cancer drug resistance. Introduction of mutated forms of PTEN, which lacked lipid phosphatase activity, increased the resistance of the MCF-7 cells to doxorubicin, suggesting that these lipid phosphatase deficient PTEN mutants acted as dominant negative mutants to suppress wild-type PTEN activity. Finally, the PI3K/PTEN/Akt pathway appears to be more prominently involved in prostate cancer drug resistance than the Raf/MEK/ERK pathway. Some advanced prostate cancer cells express elevated levels of activated Akt which may suppress Raf activation. Introduction of activated forms of Akt increased the drug resistance of advanced prostate cancer cells. In contrast, introduction of activated forms of Raf did not increase the drug resistance of the prostate cancer cells. In contrast to the results observed in hematopoietic cells, Raf may normally promote differentiation in prostate cells which is suppressed in advanced prostate cancer due to increased expression of activated Akt arising from PTEN mutation. Thus in advanced prostate cancer it may be advantageous to induce Raf expression to promote differentiation, while in hematopoietic cancers it may be beneficial to inhibit Raf/MEK/ERK-induced proliferation

  9. Redox regulation of tumor suppressor PTEN in cancer and aging (Review).

    Science.gov (United States)

    Kitagishi, Yasuko; Matsuda, Satoru

    2013-03-01

    Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) has been shown to act as a tumor suppressor whose function includes important roles in regulating oxidative stress, indicating a potential role in oxidative damage-associated cancer. Accumulating evidence has revealed that PTEN also acts as a pivotal determinant of cell fate, regarding senescence and apoptosis, which is mediated by intracellular reactive oxygen species (ROS) generation. Cells are continuously exposed to ROS, which represent mutagens and are thought to be a major contributor to cancer and the aging process. Therefore, cellular ROS sensing and metabolism are firmly regulated by a variety of proteins involved in the redox mechanism. In this review, PTEN and the roles of oxidative stress in phosphoinositide-3 kinase/AKT signaling are summarized with a focus on the links between the pathways and ROS in cancer and aging.

  10. PTEN and p53 cross-regulation induced by soy isoflavone genistein promotes mammary epithelial cell cycle arrest and lobuloalveolar differentiation

    OpenAIRE

    2010-01-01

    The tumor suppressors phosphatase and tensin homologue deleted on chromosome ten (PTEN) and p53 are closely related to the pathogenesis of breast cancer, yet pathway-specific mechanisms underlying their participation in mediating the protective actions of dietary bioactive components on breast cancer risk are poorly understood. We recently showed that dietary exposure to the soy isoflavone genistein (GEN) induced PTEN expression in mammary epithelial cells in vivo and in vitro, consistent wit...

  11. No association between phosphatase and tensin homolog genetic polymorphisms and colon cancer

    Institute of Scientific and Technical Information of China (English)

    Lynette S Phillips; Cheryl L Thompson; Alona Merkulova; Sarah J Plummer; Thomas C Tucker; Graham Casey; Li Li

    2009-01-01

    AIM: To investigate the association between single nucleotide polymorphisms (SNPs) in the phosphatase and tensin homolog (PTEN) tumor suppressor gene and risk of colon cancer. METHODS: We utilized a population-based casecontrol study of incident colon cancer individuals ( n = 421) and controls ( n = 483) aged ≥ 30 years to conduct a comprehensive tagSNP association analysis of the PTEN gene. RESULTS: None of the PTEN SNPs were statistically significantly associated with colon cancer when controlled for age, gender, and race, or when additionally adjusted for other known risk factors ( P > 0.05). Haplotype analyses similarly showed no association between the PTEN gene and colon cancer. CONCLUSION: Our study does not support PTEN as a colon cancer susceptibility gene.

  12. The association between phosphatase and tensin homolog hypermethylation and patients with breast cancer, a meta-analysis and literature review

    Science.gov (United States)

    Lu, Yi-Min; Cheng, Feng; Teng, Li-Song

    2016-01-01

    The Phosphatase and tensin homolog (PTEN) protein is a negative regulator of the Akt pathway, leading to suppression of apoptois and increased cell survival. Its role as a tumor-suppressor gene has been adequately substantiated, and PTEN hypermethylation has been demonstrated in familial and sporadic cancers. However, the association and clinical significance between PTEN hypermethylation and breast cancer remains unclear. In this study, we systematically reviewed studies of PTEN hypermethylation and breast cancer and quantify the association between PTEN hypermethylation and breast cancer using meta-analysis methods. The pooled OR, 22.30, 95% confidential intervals, CI = 1.98–251.51, P = 0.01, which demonstrates that loss of PTEN expression by hypermethylation plays a critical role in the early tumorigenesis of ductal carcinoma in situ (DCIS). In addition, PTEN hypermethylation also is detected in invasive ductal carcinomas (IDCs) and is significantly higher than in normal controls, OR = 23.32, 95% CI = 10.43–52.13, P < 0.00001. Further analysis did not show significant correlation between PTEN hypermethylation and the progression of breast cancer, estrogen receptor (ER), progesterone receptor (PgR), as well as HER2 status. These results indicate the PTEN hypermethylation is significantly associated with both DCIS and IDCs. The detection of PTEN hypermethylation could be an early tumorigenesis marker for breast cancer patients. PMID:27620353

  13. A type 2C protein phosphatase FgPtc3 is involved in cell wall integrity, lipid metabolism, and virulence in Fusarium graminearum.

    Directory of Open Access Journals (Sweden)

    Jinhua Jiang

    Full Text Available Type 2C protein phosphatases (PP2Cs play important roles in regulating many biological processes in eukaryotes. Currently, little is known about functions of PP2Cs in filamentous fungi. The causal agent of wheat head blight, Fusarium graminearum, contains seven putative PP2C genes, FgPTC1, -3, -5, -5R, -6, -7 and -7R. In order to investigate roles of these PP2Cs, we constructed deletion mutants for all seven PP2C genes in this study. The FgPTC3 deletion mutant (ΔFgPtc3-8 exhibited reduced aerial hyphae formation and deoxynivalenol (DON production, but increased production of conidia. The mutant showed increased resistance to osmotic stress and cell wall-damaging agents on potato dextrose agar plates. Pathogencity assays showed that ΔFgPtc3-8 is unable to infect flowering wheat head. All of the defects were restored when ΔFgPtc3-8 was complemented with the wild-type FgPTC3 gene. Additionally, the FgPTC3 partially rescued growth defect of a yeast PTC1 deletion mutant under various stress conditions. Ultrastructural and histochemical analyses showed that conidia of ΔFgPtc3-8 contained an unusually high number of large lipid droplets. Furthermore, the mutant accumulated a higher basal level of glycerol than the wild-type progenitor. Quantitative real-time PCR assays showed that basal expression of FgOS2, FgSLT2 and FgMKK1 in the mutant was significantly higher than that in the wild-type strain. Serial analysis of gene expression in ΔFgPtc3-8 revealed that FgPTC3 is associated with various metabolic pathways. In contrast to the FgPTC3 mutant, the deletion mutants of FgPTC1, FgPTC5, FgPTC5R, FgPTC6, FgPTC7 or FgPTC7R did not show aberrant phenotypic features when grown on PDA medium or inoculated on wheat head. These results indicate FgPtc3 is the key PP2C that plays a critical role in a variety of cellular and biological functions, including cell wall integrity, lipid and secondary metabolisms, and virulence in F. graminearum.

  14. Glandular epithelial AR inactivation enhances PTEN deletion-induced uterine pathology.

    Science.gov (United States)

    Choi, Jaesung Peter; Zheng, Yu; Handelsman, David J; Simanainen, Ulla

    2016-05-01

    Phosphatase and tensin homolog (PTEN) deletion induces uterine pathology, whereas androgen actions via androgen receptor (AR) support uterine growth and therefore may modify uterine cancer risk. We hypothesized that the androgen actions mediated via uterine glandular epithelial AR could modify PTEN deletion-induced uterine pathology. To test our hypothesis, we developed uterine glandular epithelium-specific PTEN and/or AR knockout mouse models comparing the uterine pathology among wild-type (WT), glandular epithelium-specific AR inactivation (ugeARKO), PTEN deletion (ugePTENKO), and the combined PTEN and AR knockout (ugePTENARKO) female mice. The double knockout restricted to glandular epithelium showed that AR inactivation enhanced PTEN deletion-induced uterine pathology with development of intraepithelial neoplasia by 20 weeks of age. In ugePTENARKO, 6/10 (60%) developed intraepithelial neoplasia, whereas 3/10 (30%) developed only glandular hyperplasia in ugePTENKO uterus. No uterine pathology was observed in WT (n=8) and ugeARKO (n=7) uteri. Uterine weight was significantly (P=0.002) increased in ugePTENARKO (374±97 mg (mean±s.e.)) compared with WT (97±6 mg), ugeARKO (94±12 mg), and ugePTENKO (205±33 mg). Estrogen receptor alpha (ERα) and P-AKT expression was modified by uterine pathology but did not differ between ugePTENKO and ugePTENARKO, suggesting that its expressions are not directly affected by androgens. However, progesterone receptor (PR) expression was reduced in ugePTENARKO compared to ugePTENKO uterus, suggesting that PR expression could be regulated by glandular epithelial AR inactivation. In conclusion, glandular epithelial AR inactivation (with persistent stromal AR action) enhanced PTEN deletion-induced uterine pathology possibly by downregulating PR expression in the uterus.

  15. PTEN and p16 genes as epigenetic biomarkers in oral squamous cell carcinoma (OSCC): a study on south Indian population.

    Science.gov (United States)

    Sushma, P S; Jamil, Kaiser; Kumar, P Uday; Satyanarayana, U; Ramakrishna, M; Triveni, B

    2016-06-01

    Phosphatase and tensin homolog (PTEN) and p16INK4a (p16) genes are tumor suppressor genes, associated with epigenetic alterations. PTEN and p16 promoter hypermethylation is a major epigenetic silencing mechanism leading to cancer. The cooperation between PTEN and p16 in pathogenesis of cancers suggest that their combination might be considered as potential molecular marker for specific subgroups of patients. Hence, the present study aimed to investigate whether PTEN and p16 promoter methylations were involved in oral squamous cell carcinoma (OSCC) in south Indian subjects. DNA methylation quantitative analyses of the two candidate tumor suppressor genes PTEN and p16 were performed by methylation-specific polymerase chain reaction (MSP). Fifty OSCC biopsy samples and their corresponding non-malignant portions as controls were studied comparatively. The methylation status was correlated with the clinical manifestations. Twelve out of 50 patients (24 %) were found to be methylated for PTEN gene, whereas methylation of the p16 gene occurred in 19 out of 50 cases (38 %). A statistically significant result was obtained (P = p16 genes. PTEN and p16 promoter methylation may be the main mechanism leading to the low expression of PTEN and p16 genes indicating the progress of tumor development. Our data suggest that a low PTEN and p16 expression due to methylation may contribute to the cancer progression and could be useful for prognosis of OSCC. Therefore, analysis of promoter methylation in such genes may provide a biomarker valuable for early detection of oral cancer.

  16. miR-17 inhibitor suppressed osteosarcoma tumor growth and metastasis via increasing PTEN expression

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Yong, E-mail: gaoyongunion@163.com [Department of Orthopedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022 (China); Luo, Ling-hui [Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022 (China); Li, Shuai; Yang, Cao [Department of Orthopedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022 (China)

    2014-02-07

    Highlights: • miR-17 was increased in OS tissues and cell lines. • Inhibition of miR-17 suppressed OS cell proliferation. • Inhibition of miR-17 suppressed OS cell migration and invasion. • PTEN was a target of miR-17. • miR-17 was negatively correlated with PTEN in OS tissues. - Abstract: MicroRNAs (miRNAs) play essential roles in cancer development and progression. Here, we investigated the role of miR-17 in the progression and metastasis of osteosarcoma (OS). miR-17 was frequently increased in OS tissues and cell lines. Inhibition of miR-17 in OS cell lines substantially suppressed cell proliferation, migration, and invasion. Phosphatase and tensin homolog (PTEN) was identified as a target of miR-17, and ectopic expression of miR-17 inhibited PTEN by direct binding to its 3′-untranslated region (3′-UTR). Expression of miR-17 was negatively correlated with PTEN in OS tissues. Together, these findings indicate that miR-17 acts as an oncogenic miRNA and may contribute to the progression and metastasis of OS, suggesting miR-17 as a potential novel diagnostic and therapeutic target of OS.

  17. Conditional Inactivation of Pten with EGFR Overexpression in Schwann Cells Models Sporadic MPNST

    Directory of Open Access Journals (Sweden)

    Vincent W. Keng

    2012-01-01

    Full Text Available The genetic mechanisms involved in the transformation from a benign neurofibroma to a malignant sarcoma in patients with neurofibromatosis-type-1- (NF1-associated or sporadic malignant peripheral nerve sheath tumors (MPNSTs remain unclear. It is hypothesized that many genetic changes are involved in transformation. Recently, it has been shown that both phosphatase and tensin homolog (PTEN and epidermal growth factor receptor (EGFR play important roles in the initiation of peripheral nerve sheath tumors (PNSTs. In human MPNSTs, PTEN expression is often reduced, while EGFR expression is often induced. We tested if these two genes cooperate in the evolution of PNSTs. Transgenic mice were generated carrying conditional floxed alleles of Pten, and EGFR was expressed under the control of the 2′,3′-cyclic nucleotide 3′phosphodiesterase (Cnp promoter and a desert hedgehog (Dhh regulatory element driving Cre recombinase transgenic mice (Dhh-Cre. Complete loss of Pten and EGFR overexpression in Schwann cells led to the development of high-grade PNSTs. In vitro experiments using immortalized human Schwann cells demonstrated that loss of PTEN and overexpression of EGFR cooperate to increase cellular proliferation and anchorage-independent colony formation. This mouse model can rapidly recapitulate PNST onset and progression to high-grade PNSTs, as seen in sporadic MPNST patients.

  18. Honey bee PTEN--description, developmental knockdown, and tissue-specific expression of splice-variants correlated with alternative social phenotypes.

    Directory of Open Access Journals (Sweden)

    Navdeep S Mutti

    Full Text Available BACKGROUND: Phosphatase and TENsin (PTEN homolog is a negative regulator that takes part in IIS (insulin/insulin-like signaling and Egfr (epidermal growth factor receptor activation in Drosophila melanogaster. IIS and Egfr signaling events are also involved in the developmental process of queen and worker differentiation in honey bees (Apis mellifera. Here, we characterized the bee PTEN gene homologue for the first time and begin to explore its potential function during bee development and adult life. RESULTS: Honey bee PTEN is alternatively spliced, resulting in three splice variants. Next, we show that the expression of PTEN can be down-regulated by RNA interference (RNAi in the larval stage, when female caste fate is determined. Relative to controls, we observed that RNAi efficacy is dependent on the amount of PTEN dsRNA that is delivered to larvae. For larvae fed queen or worker diets containing a high amount of PTEN dsRNA, PTEN knockdown was significant at a whole-body level but lethal. A lower dosage did not result in a significant gene down-regulation. Finally, we compared same-aged adult workers with different behavior: nursing vs. foraging. We show that between nurses and foragers, PTEN isoforms were differentially expressed within brain, ovary and fat body tissues. All isoforms were expressed at higher levels in the brain and ovaries of the foragers. In fat body, isoform B was expressed at higher level in the nurse bees. CONCLUSION: Our results suggest that PTEN plays a central role during growth and development in queen- and worker-destined honey bees. In adult workers, moreover, tissue-specific patterns of PTEN isoform expression are correlated with differences in complex division of labor between same-aged individuals. Therefore, we propose that knowledge on the roles of IIS and Egfr activity in developmental and behavioral control may increase through studies of how PTEN functions can impact bee social phenotypes.

  19. Promoting Axon Regeneration in the Adult CNS by Modulation of the PTEN/mTOR Pathway

    OpenAIRE

    2008-01-01

    The failure of axons to regenerate is a major obstacle for functional recovery after central nervous system (CNS) injury. Removing extracellular inhibitory molecules results in limited axon regeneration in vivo. To test for the role of intrinsic impediments to axon regrowth, we analyzed cell growth control genes using a virus-assisted in vivo conditional knockout approach. Deletion of PTEN (phosphatase and tensin homolog), a negative regulator of the mammalian target of rapamycin (mTOR) pathw...

  20. Growth and activation of PI-3K/PKB and Akt by stromal cell-derived factor 1α in endometrial carcinoma cells with expression of suppressor endoprotein PTEN

    Institute of Scientific and Technical Information of China (English)

    LI Xiao-ping; ZHAO Dan; GAO Min; ZHAO Chao; WANG Jian-liu; WEI Li-hui

    2006-01-01

    Background Mutation or deletion in the phosphatase and tensin homologue deleted on chromosome ten (PTEN)gene has been identified as an important cause of endometrial carcinoma; stromal cell derived factor-1α (SDF-1α)exerts growth-promoting effects on endometrial cancer cells through activation of the PI-3 kinase/Akt pathway and downstream effectors such as extracellular-responsive kinase (ERK). In this study, a plasmid containing the PTEN gene was transfected into Ishikawa cells to investigate the difference in growth and signal transduction between Ishikawa-PTEN and Ishikawa cells after SDF-1α stimulation, and to study mechanisms of the involvement of PTEN protein in endometrial carcinoma development.Methods Ishikawa cells were transfected with a plasmid (pLXSN-PTEN) containing the PTEN gene and a plasmid (pLXSN-EGFP) with enhanced green fluorescent protein (EGFP). Cells were then screened to obtain Ishikawa-PTEN cells and Ishikawa-neo cells that can both stably express PTEN protein and EGFP. Expression of PTEN protein, phosphorylation levels of AKT and ERK (pAKT and pERK) and growth differences in Ishikawa-PTEN, Ishikawa-neo and Ishikawa cells before and after SDF-1α stimulation were then determined by Western blots and MTT assays.Results Western blot analysis showed that Ishikawa cells produced PTEN after transfection with the PTEN gene. At 15 minutes after SDF-1α stimulation, the pAKT level of Ishikawa-PTEN cells was lower than that of Ishikawa-neo cells and Ishikawa cells. There was no significant difference in pERK levels among the three cell lines. The positive effect of SDF-1α on Ishikawa-PTEN cells growth was markedly less than the effect on Ishikawa-neo and Ishikawa cells. However, in the absence of SDF-1α stimulation (baseline), the pAKT level in Ishikawa-PTEN cells was less than that in Ishikawa cells. There was a significant difference in growth between the Ishikawa-PTEN cells and the Ishikawa-neo cells.Conclusions PTEN gene transfection can

  1. Computational Analysis of PTEN Gene Mutation

    Directory of Open Access Journals (Sweden)

    Siew-Kien Mah

    2012-01-01

    Full Text Available Post-genomic data can be efficiently analyzed using computational tools. It has the advantage over the biochemical and biophysical methods in term of higher coverage. In this research, we adopted a computational analysis on PTEN gene mutation.  Mutation in PTEN is responsible for many human diseases. The results of this research provide insights into the protein domains of PTEN and the distribution of mutation.

  2. Phosphatase and Tensin Homolog Is a Potential Target for Ovarian Cancer Sensitization to Cytotoxic Agents.

    Science.gov (United States)

    McCormick, Aiste; Earp, Eleanor; Leeson, Charlotte; Dixon, Michelle; O'Donnell, Rachel; Kaufmann, Angelika; Edmondson, Richard J

    2016-05-01

    The phosphatase and tensin homolog (PTEN) tumor suppressor protein has been found to be inactivated or mutated in various human malignancies and to play a role in cisplatin and poly(ADP-ribose) polymerase inhibitor sensitivity. In this study, we assessed the association of PTEN loss with homologous recombination (HR) deficiency and increased chemosensitivity. The PTEN knockdown models were created using MISSION shRNA lentiviral transduction particles in cell lines derived from normal ovarian surface epithelium and a mixed endometrioid/clear-cell carcinoma. Sensitivity to common therapeutics was assessed using sulforhodamine B assay. Twenty-eight unselected primary epithelial ovarian cancer cultures derived from ascitic fluid collected at the time of surgery and matched genomic DNA were assessed for PTEN mutations using polymerase chain reaction amplification and Sanger sequencing and for mRNA expression using quantitative reverse transcription-polymerase chain reaction; HR was determined using γH2AX/RAD51 assay. The Cancer Genome Atlas data were analyzed using cBioPortal. In the carcinoma cell line, the PTEN knockdown enhanced sensitivity to cisplatin, rucaparib, doxorubicin, camptothecin, paclitaxel, and irradiation. In the primary ovarian cancer cultures, 2 point mutations were found (1105T>TG, 25L>L in 6 cultures and 1508G>GA, 159R>R in 4 cultures). The PTEN mRNA expression varied over 40-fold between the cultures, but did not correlate with HR status or in vitro sensitivity to cisplatin or rucaparib. The Cancer Genome Atlas data showed a rate of 8% alteration in PTEN and a trend toward improved survival in PTEN-mutated cases. These data indicate that although PTEN mutations in ovarian cancer are rare, PTEN inhibition results in therapeutic sensitization. Therefore, PTEN may be an important therapeutic target, in at least some cancers.

  3. PRL-3 promotes the peritoneal metastasis of gastric cancer through the PI3K/Akt signaling pathway by regulating PTEN.

    Science.gov (United States)

    Xiong, Jianbo; Li, Zhengrong; Zhang, Yang; Li, Daojiang; Zhang, Guoyang; Luo, Xianshi; Jie, Zhigang; Liu, Yi; Cao, Yi; Le, Zhibiao; Tan, Shengxing; Zou, Wenyu; Gong, Peitao; Qiu, Lingyu; Li, Yuanyuan; Wang, Huan; Chen, Heping

    2016-10-01

    Peritoneal metastasis is the most frequent cause of death in patients with advanced gastric carcinoma (GC). The phosphatase of regenerating liver-3 (PRL-3) is recognized as an oncogene and plays an important role in GC peritoneal metastasis. However, the mechanism of how PRL-3 regulates GC invasion and metastasis is unknown. In the present study, we found that PRL-3 presented with high expression in GC with peritoneal metastasis, but phosphatase and tensin homologue (PTEN) was weakly expressed. The p-PTEN/PTEN ratio was also higher in GC with peritoneal metastasis than that in the normal gastric tissues. We also found the same phenomenon when comparing the gastric mucosa cell line with the GC cell lines. After constructing a wild-type and a mutant-type plasmid without enzyme activity and transfecting them into GC SGC7901 cells, we showed that only PRL-3 had enzyme activity to downregulate PTEN and cause PTEN phosphorylation. The results also showed that PRL-3 increased the expression levels of MMP-2/MMP-9 and promoted the migration and invasion of the SGC7901 cells. Knockdown of PRL-3 decreased the expression levels of MMP-2/MMP-9 significantly, which further inhibited the migration and invasion of the GC cells. PRL-3 also increased the expression ratio of p-Akt/Akt, which indicated that PRL-3 may mediate the PI3K/Akt pathway to promote GC metastasis. When we transfected the PTEN siRNA plasmid into the PRL-3 stable low expression GC cells, the expression of p-Akt, MMP-2 and MMP-9 was reversed. In conclusion, our results provide a bridge between PRL-3 and PTEN; PRL-3 decreased the expression of PTEN as well as increased the level of PTEN phosphorylation and inactivated it, consequently activating the PI3K/Akt signaling pathway, and upregulating MMP-2/MMP-9 expression to promote GC cell peritoneal metastasis.

  4. Phosphorylation of PTEN increase in pathological right ventricular hypertrophy in rats with chronic hypoxia induced pulmonary hypertension

    Institute of Scientific and Technical Information of China (English)

    Nie Xin; Shi Yiwei; Yu Wenyan; Xu Jianying; Hu Xiaoyun; Du Yongcheng

    2014-01-01

    Background Phosphatase and tensin homologue on chromosome ten (PTEN) acts as a convergent nodal signalling point for cardiomyocyte hypertrophy,growth and survival.However,the role of PTEN in cardiac conditions such as right ventricular hypertrophy caused by chronic hypoxic pulmonary,hypertension remains unclear.This study preliminarily discussed the role of PTEN in the cardiac response to increased pulmonary vascular resistance using the hypoxia-induced PH rats.Methods Male Sprague Dawley rats were exposed to 10% oxygen for 1,3,7,14 or 21 days to induce hypertension and right ventricular hypertrophy.Right ventricular systolic pressure was measured via catheterization.Hypertrophy index was calculated as the ratio of right ventricular mass to left ventricle plus septum mass.Tissue morphology and fibrosis were measured using hematoxylin,eosin and picrosirius red staining.The expression and phosphorylation levels of PTEN in ventricles were determined by real time PCR and Western blotting.Results Hypoxic exposure of rats resulted in pathological hypertrophy,interstitial fibrosis and remodelling of the right ventricle.The phosphorylation of PTEN increased significantly in the hypertrophic right ventricle compared to the normoxic control group.There were no changes in protein expression in either ventricle.Conclusion Hypoxia induced pulmonary hypertension developed pathological right ventricular hypertrophy and remodelling probablv related to an increased phosohorvlation of PTEN.

  5. PTEN microdeletions in T-cell acute lymphoblastic leukemia are caused by illegitimate RAG-mediated recombination events.

    Science.gov (United States)

    Mendes, Rui D; Sarmento, Leonor M; Canté-Barrett, Kirsten; Zuurbier, Linda; Buijs-Gladdines, Jessica G C A M; Póvoa, Vanda; Smits, Willem K; Abecasis, Miguel; Yunes, J Andres; Sonneveld, Edwin; Horstmann, Martin A; Pieters, Rob; Barata, João T; Meijerink, Jules P P

    2014-07-24

    Phosphatase and tensin homolog (PTEN)-inactivating mutations and/or deletions are an independent risk factor for relapse of T-cell acute lymphoblastic leukemia (T-ALL) patients treated on Dutch Childhood Oncology Group or German Cooperative Study Group for Childhood Acute Lymphoblastic Leukemia protocols. Some monoallelic mutated or PTEN wild-type patients lack PTEN protein, implying that additional PTEN inactivation mechanisms exist. We show that PTEN is inactivated by small deletions affecting a few exons in 8% of pediatric T-ALL patients. These microdeletions were clonal in 3% and subclonal in 5% of patients. Conserved deletion breakpoints are flanked by cryptic recombination signal sequences (cRSSs) and frequently have non-template-derived nucleotides inserted in between breakpoints, pointing to an illegitimate RAG recombination-driven activity. Identified cRSSs drive RAG-dependent recombination in a reporter system as efficiently as bona fide RSSs that flank gene segments of the T-cell receptor locus. Remarkably, equivalent microdeletions were detected in thymocytes of healthy individuals. Microdeletions strongly associate with the TALLMO subtype characterized by TAL1 or LMO2 rearrangements. Primary and secondary xenotransplantation of TAL1-rearranged leukemia allowed development of leukemic subclones with newly acquired PTEN microdeletions. Ongoing RAG activity may therefore actively contribute to the acquisition of preleukemic hits, clonal diversification, and disease progression. © 2014 by The American Society of Hematology.

  6. Poor prognostic clinicopathologic features correlate with VEGF expression but not with PTEN expression in squamous cell carcinoma of the larynx

    Directory of Open Access Journals (Sweden)

    Karagoz Filiz

    2010-06-01

    Full Text Available Abstract Background The aim of this study was to assess the relationship between expression of vascular endothelial growth factor (VEGF and phosphatase and tensin homolog deleted in chromosome ten (PTEN, angiogenesis and clinicopathological parameters of squamous cell carcinoma of the larynx. Methods We examined immunohistochemical expression of VEGF and PTEN and CD34 for microvessel density (MVD in sections of formalin-fixed, paraffin embedded tissue blocks of 140 patients with squamous cell carcinoma of the larynx. The intensity of VEGF and PTEN staining and the proportion of cells staining were scored. Results The tumor grade was not significantly related to PTEN expression, but it was to VEGF expression (p = 0.400; p = 0.015, respectively. While there was no significant relationship between PTEN expression and tumor size and cartilage invasion (p = 0.311, p = 0.128, there was a significant relationship between the severity of VEGF expression and tumor size (p = 0.006 and lymph node metastasis (p = 0.048 but not cartilage invasion (p = 0.129. MVD was significantly higher in high-grade tumors (p = 0.003 but had no significant relationship between MVD, lymph node metastasis, and cartilage invasion (p = 0.815, p = 0.204. There was also no significant relationship between PTEN and VEGF expression (p = 0.161 and between PTEN and VEGF expression and the MVD (p = 0.120 and p = 0.175, respectively. Conclusions Increased VEGF expression may play an important role in the outcome of squamous cell carcinoma of the larynx. PTEN expression was not related to VEGF expression and clinicopathological features of squamous cell carcinoma of the larynx.

  7. Mutant PTEN in Cancer : Worse Than Nothing

    NARCIS (Netherlands)

    Leslie, Nick R; den Hertog, Jeroen

    2014-01-01

    Tumor suppressors block the development of cancer and are often lost during tumor development. Papa et al. show that partial loss of normal PTEN tumor suppressor function can be compounded by additional disruption caused by the expression of inactive mutant PTEN protein. This has significant

  8. Activation of c-Src and Fyn kinases by protein tyrosine phosphatase RPTPalpha is substrate-specific and compatible with lipid raft localization

    DEFF Research Database (Denmark)

    Vacaresse, Nathalie; Møller, Bente; Danielsen, Erik Michael;

    2008-01-01

    and the lipid raft scaffolding protein Cbp/PAG. A significant fraction of RPTPa is present in lipid rafts, where its targets Fyn and Cbp/PAG reside, and growth factor-mediated SFK activation within this compartment is strictly dependent on RPTPa. Forced concentration of RPTPa into lipid rafts is compatible...

  9. PTEN, Longevity and Age-Related Diseases

    Directory of Open Access Journals (Sweden)

    Izak S. Tait

    2013-12-01

    Full Text Available Since the discovery of PTEN, this protein has been shown to be an effective suppressor of cancer and a contributor to longevity. This report will review, in depth, the associations between PTEN and other molecules, its mutations and regulations in order to present how PTEN can be used to increase longevity. This report will collect recent research of PTEN and use this to discuss PTEN’s role in caloric restriction, antioxidative defense of DNA-damage and the role it plays in suppressing tumors. The report will also discuss that variety of ways that PTEN can be compromised, through mutations, complete loss of alleles and its main antagonist, the PI3K/AKT pathway.

  10. Simultaneous inactivation of Par-4 and PTEN in vivo leads to synergistic NF-κB activation and invasive prostate carcinoma

    Science.gov (United States)

    Fernandez-Marcos, Pablo J.; Abu-Baker, Shadi; Joshi, Jayashree; Galvez, Anita; Castilla, Elias A.; Cañamero, Marta; Collado, Manuel; Saez, Carmen; Moreno-Bueno, Gema; Palacios, Jose; Leitges, Michael; Serrano, Manuel; Moscat, Jorge; Diaz-Meco, Maria T.

    2009-01-01

    Prostate cancer is one of the most common neoplasias in men. The tumor suppressor Par-4 is an important negative regulator of the canonical NF-κB pathway and is highly expressed in prostate. Here we show that Par-4 expression is lost in a high percentage of human prostate carcinomas, and this occurs in association with phosphatase and tensin homolog deleted from chromosome 10 (PTEN) loss. Par-4 null mice, similar to PTEN-heterozygous mice, only develop benign prostate lesions, but, importantly, concomitant Par-4 ablation and PTEN-heterozygosity lead to invasive prostate carcinoma in mice. This strong tumorigenic cooperation is anticipated in the preneoplastic prostate epithelium by an additive increase in Akt activation and a synergistic stimulation of NF-κB. These results establish the cooperation between Par-4 and PTEN as relevant for the development of prostate cancer and implicate the NF-κB pathway as a critical event in prostate tumorigenesis. PMID:19470463

  11. Atorvastatin Inhibits Myocardial Apoptosis in a Swine Model of Coronary Microembolization by Regulating PTEN/PI3K/Akt Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Jiangyou Wang

    2016-01-01

    Full Text Available Background/Aims: Phosphatase and tensin homolog deleted on chromosome ten (PTEN has been recognized as a promoter of apoptosis in various tissues, and revealed to be up-regulated in circumstances of coronary microembolization (CME. However, whether this functional protein could be modified by pretreatment of atorvastatin in models of CME has not been disclosed yet. Methods: Swine CME was induced by intra-coronary injection of inertia plastic microspheres (diameter 42 μm into left anterior descending coronary, with or without pretreatment of atorvastatin or PTEN siRNA. Echocardiologic measurements, pathologic examination, TUNEL staining and western blotting were applied to assess their functional, morphological and molecular effects in CME. Results: PTEN were aberrantly up-regulated in cardiomyocytes following CME, with both the mRNA and protein levels increased after CME modeling. Pretreatment with atorvastatin could attenuate the induction of PTEN. Furthermore, down-regulation of PTEN in vivo via siRNA was associated with an improved cardiac function, attenuated myocardial apoptosis, and concomitantly inhibited expressions of key proapoptotic proteins such as Bax, cleaved-caspase-3. Interestingly, atorvastatin could markedly attenuate PTEN expression and therefore partially reverse cardiac dysfunction and attenuate the apoptosis of the myocardium following CME. Conclusion: Modulation of PTEN was probably as a potential mechanism involved in the beneficial effects of pretreatment of atorvastatin to cardiac function and apoptosis in large animal models of CME.

  12. Expression of PIK3CA, PTEN mRNA and PIK3CA mutations in primary breast cancer

    DEFF Research Database (Denmark)

    Palimaru, Irina; Brügmann, Anja; Wium-Andersen, Marie Kim;

    2013-01-01

    tissue samples of breast carcinoma and normal breast tissue were obtained from 175 breast cancer patients at the time of primary surgery, of these 105 patients were lymph node positive. Expression of PIK3CA and PTEN mRNA was quantified with Quantitative Real Time PCR. Somatic mutations in exon 9 and exon......PURPOSE: High activity of the intracellular phosphatidylinositol-3 kinase (PI3K) pathway is common in breast cancer. Here, we explore differences in expression of important PI3K pathway regulators: the activator, phosphatidylinositol-3-kinase catalytic subunit alpha (PIK3CA), and the tumour...... suppressor, phosphatase and tensin homolog (PTEN), in breast carcinoma tissue and normal breast tissue. Furthermore, we examine whether expression of PIK3CA and PTEN mRNA and occurrence of PIK3CA mutations are associated with lymph node metastases in patients with primary breast cancer. METHODS: Paired...

  13. Dual regulatory role for phosphatase and tensin homolog in specification of intestinal endocrine cell subtypes

    Institute of Scientific and Technical Information of China (English)

    Sébastien AB Roy; Marie-Josée Langlois; Julie C Carrier; Fran(c)ois Boudreau; Nathalie Rivard; Nathalie Perreault

    2012-01-01

    AIM:To investigate the impact of phosphatase and tensin homolog (Pten) in the specification of intestinal enteroendocrine subpopulations.METHODS:Using the Cre/IoxP system,a mouse with conditional intestinal epithelial Pten deficiency was generated.Pten mutant mice and controls were sacrificed and small intestines collected for immunofluorescence and quantitative real-time polymerase chain reaction.Blood was collected on 16 h fasted mice by cardiac puncture.Enzyme-linked immunosorbent assay was used to measure blood circulating ghrelin,somatostatin (SST) and glucose-dependent insulinotropic peptide (GIP) levels.RESULTS:Results show an unexpected dual regulatory role for epithelial Pten signalling in the specification/differentiation of enteroendocrine cell subpopulations in the small intestine.Our data indicate that Pten positively regulates chromogranin A (CgA) expressing subpopulations,including cells expressing secretin,ghrelin,gastrin and cholecystokinin (CCK).In contrast,Pten negatively regulates the enteroendocrine subtype specification of non-expressing CgA cells such as GIP and SST expressing cells.CONCLUSION:The present results demonstrate that Pten signalling favours the enteroendocrine progenitor to specify into cells expressing CgA including those producing CCK,gastrin and ghrelin.

  14. Superoxide anion radicals induce IGF-1 resistance through concomitant activation of PTP1B and PTEN.

    Science.gov (United States)

    Singh, Karmveer; Maity, Pallab; Krug, Linda; Meyer, Patrick; Treiber, Nicolai; Lucas, Tanja; Basu, Abhijit; Kochanek, Stefan; Wlaschek, Meinhard; Geiger, Hartmut; Scharffetter-Kochanek, Karin

    2015-01-01

    The evolutionarily conserved IGF-1 signalling pathway is associated with longevity, metabolism, tissue homeostasis, and cancer progression. Its regulation relies on the delicate balance between activating kinases and suppressing phosphatases and is still not very well understood. We report here that IGF-1 signalling in vitro and in a murine ageing model in vivo is suppressed in response to accumulation of superoxide anions (O2∙-) in mitochondria, either by chemical inhibition of complex I or by genetic silencing of O2∙--dismutating mitochondrial Sod2. The O2∙--dependent suppression of IGF-1 signalling resulted in decreased proliferation of murine dermal fibroblasts, affected translation initiation factors and suppressed the expression of α1(I), α1(III), and α2(I) collagen, the hallmarks of skin ageing. Enhanced O2∙- led to activation of the phosphatases PTP1B and PTEN, which via dephosphorylation of the IGF-1 receptor and phosphatidylinositol 3,4,5-triphosphate dampened IGF-1 signalling. Genetic and pharmacologic inhibition of PTP1B and PTEN abrogated O2∙--induced IGF-1 resistance and rescued the ageing skin phenotype. We thus identify previously unreported signature events with O2∙-, PTP1B, and PTEN as promising targets for drug development to prevent IGF-1 resistance-related pathologies.

  15. Loss of PTEN expression is associated with increased risk of recurrence after prostatectomy for clinically localized prostate cancer.

    Science.gov (United States)

    Chaux, Alcides; Peskoe, Sarah B; Gonzalez-Roibon, Nilda; Schultz, Luciana; Albadine, Roula; Hicks, Jessica; De Marzo, Angelo M; Platz, Elizabeth A; Netto, George J

    2012-11-01

    PTEN (phosphatase and tensin homolog on chromosome 10) is one of the most frequently lost tumor suppressor genes in human cancers and it has been described in more than two-thirds of patients with advanced/aggressive prostate cancer. Previous studies suggest that, in prostate cancer, genomic PTEN loss is associated with tumor progression and poor prognosis. Thus, we evaluated whether immunohistochemical PTEN expression in prostate cancer glands was associated with higher risk of recurrence, using a nested case-control study that included 451 men who recurred and 451 men who did not recur with clinically localized prostate cancer treated by radical prostatectomy. Recurrence was defined as biochemical recurrence (serum prostate-specific antigen >0.2 ng/ml) or clinical recurrence (local recurrence, systemic metastases, or prostate cancer-related death). Cases and controls were matched on pathological T stage, Gleason score, race/ethnicity, and age at surgery. Odds ratios of recurrence and 95% confidence intervals were estimated using conditional logistic regression to account for the matching factors and to adjust for year of surgery, preoperative prostate-specific antigen concentrations, and status of surgical margins. Men who recurred had a higher proportion of PTEN negative expression (16 vs 11%, P=0.05) and PTEN loss (40 vs 31%, P=0.02) than controls. Men with markedly decreased PTEN staining had a higher risk of recurrence (odds ratio=1.67; 95% confidence intervals 1.09, 2.57; P=0.02) when compared with all other men. In summary, in patients with clinically localized prostate cancer treated by prostatectomy, decreased PTEN expression was associated with an increased risk of recurrence, independent of known clinicopathological factors.

  16. Higher methylation intensity induced by EBV LMP1 via NF-κB/DNMT3b signaling contributes to silencing of PTEN gene

    Science.gov (United States)

    Lyu, Xiaoming; Jiang, Qiang; Wang, Jianguo; Lu, Juan; Yao, Kaitai; Liu, Kunping; Li, Jinbang; Li, Xin

    2016-01-01

    Phosphatase and tensin homolog (PTEN) is a major tumor suppressor and usually silenced via the deletion, insertion and mutation. We previously discovered its inactivation via aberrant CpG island methylation. Here, we provide further evidence that EBV latent membrane protein 1(LMP1) can induce a higher intensity of DNA methylation at PTEN CpG islands, inactivating PTEN at the cellular and molecular level. Initially, increased methylation intensity of PTEN CpG islands was observed in EBV-infected nasopharyngeal carcinoma (NPC) cells, accompanied by decreased PTEN expression. In NPC tissue samples showing the methylation at PTEN promoter, LMP1 was highly expressed in higher methylation intensity group relative to lower intensity group, and DNA methyltransferase 3b (DNMT3b) expression was positively correlated with LMP1 expression. Moreover, transfection of LMP1 gene into EBV-negative NPC cells demonstrated that LMP1 up-regulated DNMT3b expression, leading to a higher intensity of PTEN CpG island methylation. Mechanistically, computational prediction and luciferase reporter assay identified a functional NF-κB binding site on DNMT3b promoter and the mutated NF-κB binding site abolished LMP1-mediated DNMT3b activation. Chromatin immunoprecipitation displayed that NF-κB p65 subunit constitutively bound to DNMT3b promoter, supporting the activation of DNMT3b by EBV LMP1 via NF-κB signaling. Furthermore, the expression level of DNMT3b was observed to be increased in the nuclei of LMP1-expressing NPC cells, and a NF-κB inhibitor, PDTC, counteracted LMP1-mediated DNMT3b overexpression. Thus, this study first reports that LMP1-mediated NF-κB can up-regulate DNMT3b transcription, thereby leading to relatively higher methylation intensity at PTEN CpG islands, and ultimately silencing major tumor suppressor PTEN. PMID:27223069

  17. Higher methylation intensity induced by EBV LMP1 via NF-κB/DNMT3b signaling contributes to silencing of PTEN gene.

    Science.gov (United States)

    Peng, Hong; Chen, Yuxiang; Gong, Pinggui; Cai, Longmei; Lyu, Xiaoming; Jiang, Qiang; Wang, Jianguo; Lu, Juan; Yao, Kaitai; Liu, Kunping; Li, Jinbang; Li, Xin

    2016-06-28

    Phosphatase and tensin homolog (PTEN) is a major tumor suppressor and usually silenced via the deletion, insertion and mutation. We previously discovered its inactivation via aberrant CpG island methylation. Here, we provide further evidence that EBV latent membrane protein 1(LMP1) can induce a higher intensity of DNA methylation at PTEN CpG islands, inactivating PTEN at the cellular and molecular level. Initially, increased methylation intensity of PTEN CpG islands was observed in EBV-infected nasopharyngeal carcinoma (NPC) cells, accompanied by decreased PTEN expression. In NPC tissue samples showing the methylation at PTEN promoter, LMP1 was highly expressed in higher methylation intensity group relative to lower intensity group, and DNA methyltransferase 3b (DNMT3b) expression was positively correlated with LMP1 expression. Moreover, transfection of LMP1 gene into EBV-negative NPC cells demonstrated that LMP1 up-regulated DNMT3b expression, leading to a higher intensity of PTEN CpG island methylation. Mechanistically, computational prediction and luciferase reporter assay identified a functional NF-κB binding site on DNMT3b promoter and the mutated NF-κB binding site abolished LMP1-mediated DNMT3b activation. Chromatin immunoprecipitation displayed that NF-κB p65 subunit constitutively bound to DNMT3b promoter, supporting the activation of DNMT3b by EBV LMP1 via NF-κB signaling. Furthermore, the expression level of DNMT3b was observed to be increased in the nuclei of LMP1-expressing NPC cells, and a NF-κB inhibitor, PDTC, counteracted LMP1-mediated DNMT3b overexpression. Thus, this study first reports that LMP1-mediated NF-κB can up-regulate DNMT3b transcription, thereby leading to relatively higher methylation intensity at PTEN CpG islands, and ultimately silencing major tumor suppressor PTEN.

  18. TNF-α induces vascular insulin resistance via positive modulation of PTEN and decreased Akt/eNOS/NO signaling in high fat diet-fed mice.

    Science.gov (United States)

    da Costa, Rafael Menezes; Neves, Karla Bianca; Mestriner, Fabíola Leslie; Louzada-Junior, Paulo; Bruder-Nascimento, Thiago; Tostes, Rita C

    2016-08-25

    High fat diet (HFD) induces insulin resistance in various tissues, including the vasculature. HFD also increases plasma levels of TNF-α, a cytokine that contributes to insulin resistance and vascular dysfunction. Considering that the enzyme phosphatase and tension homologue (PTEN), whose expression is increased by TNF-α, reduces Akt signaling and, consequently, nitric oxide (NO) production, we hypothesized that PTEN contributes to TNF-α-mediated vascular resistance to insulin induced by HFD. Mechanisms underlying PTEN effects were determined. Mesenteric vascular beds were isolated from C57Bl/6J and TNF-α KO mice submitted to control or HFD diet for 18 weeks to assess molecular mechanisms by which TNF-α and PTEN contribute to vascular dysfunction. Vasodilation in response to insulin was decreased in HFD-fed mice and in ex vivo control arteries incubated with TNF-α. TNF-α receptors deficiency and TNF-α blockade with infliximab abolished the effects of HFD and TNF-α on insulin-induced vasodilation. PTEN vascular expression (total and phosphorylated isoforms) was increased in HFD-fed mice. Treatment with a PTEN inhibitor improved insulin-induced vasodilation in HFD-fed mice. TNF-α receptor deletion restored PTEN expression/activity and Akt/eNOS/NO signaling in HFD-fed mice. TNF-α induces vascular insulin resistance by mechanisms that involve positive modulation of PTEN and inhibition of Akt/eNOS/NO signaling. Our findings highlight TNF-α and PTEN as potential targets to limit insulin resistance and vascular complications associated with obesity-related conditions.

  19. Microemulsion extrusion technique: a new method to produce lipid nanoparticles

    Science.gov (United States)

    de Jesus, Marcelo Bispo; Radaic, Allan; Zuhorn, Inge S.; de Paula, Eneida

    2013-10-01

    Solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) have been intensively investigated for different applications, including their use as drug and gene delivery systems. Different techniques have been employed to produce lipid nanoparticles, of which high pressure homogenization is the standard technique that is adopted nowadays. Although this method has a high efficiency, does not require the use of organic solvents, and allows large-scale production, some limitations impede its application at laboratory scale: the equipment is expensive, there is a need of huge amounts of surfactants and co-surfactants during the preparation, and the operating conditions are energy intensive. Here, we present the microemulsion extrusion technique as an alternative method to prepare lipid nanoparticles. The parameters to produce lipid nanoparticles using microemulsion extrusion were established, and the lipid particles produced (SLN, NLC, and liposomes) were characterized with regard to size (from 130 to 190 nm), zeta potential, and drug (mitoxantrone) and gene (pDNA) delivery properties. In addition, the particles' in vitro co-delivery capacity (to carry mitoxantrone plus pDNA encoding the phosphatase and tensin homologue, PTEN) was tested in normal (BALB 3T3 fibroblast) and cancer (PC3 prostate and MCF-7 breast) cell lines. The results show that the microemulsion extrusion technique is fast, inexpensive, reproducible, free of organic solvents, and suitable for small volume preparations of lipid nanoparticles. Its application is particularly interesting when using rare and/or costly drugs or ingredients (e.g., cationic lipids for gene delivery or labeled lipids for nanoparticle tracking/diagnosis).

  20. Microemulsion extrusion technique: a new method to produce lipid nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Jesus, Marcelo Bispo de, E-mail: dejesusmb@gmail.com; Radaic, Allan [University of Campinas-UNICAMP, Department of Biochemistry, Institute of Biology (Brazil); Zuhorn, Inge S. [University of Groningen, Department of Membrane Cell Biology, University Medical Center (Netherlands); Paula, Eneida de [University of Campinas-UNICAMP, Department of Biochemistry, Institute of Biology (Brazil)

    2013-10-15

    Solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) have been intensively investigated for different applications, including their use as drug and gene delivery systems. Different techniques have been employed to produce lipid nanoparticles, of which high pressure homogenization is the standard technique that is adopted nowadays. Although this method has a high efficiency, does not require the use of organic solvents, and allows large-scale production, some limitations impede its application at laboratory scale: the equipment is expensive, there is a need of huge amounts of surfactants and co-surfactants during the preparation, and the operating conditions are energy intensive. Here, we present the microemulsion extrusion technique as an alternative method to prepare lipid nanoparticles. The parameters to produce lipid nanoparticles using microemulsion extrusion were established, and the lipid particles produced (SLN, NLC, and liposomes) were characterized with regard to size (from 130 to 190 nm), zeta potential, and drug (mitoxantrone) and gene (pDNA) delivery properties. In addition, the particles' in vitro co-delivery capacity (to carry mitoxantrone plus pDNA encoding the phosphatase and tensin homologue, PTEN) was tested in normal (BALB 3T3 fibroblast) and cancer (PC3 prostate and MCF-7 breast) cell lines. The results show that the microemulsion extrusion technique is fast, inexpensive, reproducible, free of organic solvents, and suitable for small volume preparations of lipid nanoparticles. Its application is particularly interesting when using rare and/or costly drugs or ingredients (e.g., cationic lipids for gene delivery or labeled lipids for nanoparticle tracking/diagnosis)

  1. PTEN insufficiency modulates ER+ breast cancer cell cycle progression and increases cell growth in vitro and in vivo

    Directory of Open Access Journals (Sweden)

    Chiang KC

    2015-08-01

    Full Text Available Kun-Chun Chiang,1,4 Huang-Yang Chen,1 Shu-Yuan Hsu,2 Jong-Hwei S Pang,3 Shang-Yu Wang,4 Jun-Te Hsu,4 Ta-Sen Yeh,4 Li-Wei Chen,5 Sheng-Fong Kuo,6 Chi-Chin Sun,7 Jim-Ming Lee,1 Chun-Nan Yeh,4 Horng-Heng Juang21Department of General Surgery, Chang Gung Memorial Hospital, Chang Gung University, Keelung, 2Department of Anatomy, 3Graduate Institute of Clinical Medical Sciences, 4Department of General Surgery, 5Department of Gastroenterology, 6Department of Endocrinology and Metabolism, 7Department of Ophthalmology, Chang Gung Memorial Hospital, Chang Gung University, Keelung, Taiwan, Republic of China Abstract: Phosphatase and tensin homolog (PTEN, a well-known tumor suppressor gene and frequently mutated or lost in breast cancer, possesses the negative regulation function over the PI3K/Akt/mTOR pathway. PTEN insufficiency has been associated with advanced breast cancer and poor prognosis of breast cancer patients. Recently, target therapies aimed at PI3K/Akt/mTOR pathway to treat breast cancer have got popularity. However, the exact effect of PTEN on breast cancer cells is still not well understood. This study demonstrated that PTEN knockdown in MCF-7 cells strengthened the downstream gene expressions, including p-Akt, p-ERK1/2, p-mTOR, p-p70s6k, and p-GSK3ß. PTEN knockdown MCF-7 cells had increased cell growth and Ki-67 expression. Further Western blot demonstrated that p27 was repressed obviously with p21 slightly inhibited and CDK1, 2, 4, 6, cyclin A, and Cdc25C were upregulated in MCF-7 PTEN knockdown cells, leading to the higher growth rate. More importantly, PTEN knockdown MCF-7 cells had higher tumorigenesis and tumor growth in vivo. From our current work, we provided more detailed PTEN-mediated mechanisms to stimulate ER+ breast cancer cell growth. Our result may pave the way for further target therapy development used alone or in combination with other drugs for ER+ breast cancer with PTEN insufficiency.Keywords: PTEN, breast cancer, MCF-7

  2. Pten Regulates Epithelial Cytodifferentiation during Prostate Development

    DEFF Research Database (Denmark)

    Lokody, Isabel B; Francis, Jeffrey C; Gardiner, Jennifer R;

    2015-01-01

    Gene expression and functional studies have indicated that the molecular programmes involved in prostate development are also active in prostate cancer. PTEN has been implicated in human prostate cancer and is frequently mutated in this disease. Here, using the Nkx3.1:Cre mouse strain and a genetic...... deletion approach, we investigate the role of Pten specifically in the developing mouse prostate epithelia. In contrast to its role in other developing organs, this gene is dispensable for the initial developmental processes such as budding and branching. However, as cytodifferentiation progresses...... that are shared with Pten mutant prostate cancer models, including a decrease in androgen receptor regulated genes. In depth analysis of the phenotype of these mice during development revealed that loss of Pten leads to the precocious differentiation of epithelial cells towards a luminal cell fate. This study...

  3. Role of PTEN in the Tumor Microenvironment

    Science.gov (United States)

    2008-06-01

    mouse mammary tumors. Oncogene 24, 6870-6876. 11. Park ES, Lee JS, Woo HG, Zhan F, Shih JH, Shaughnessy JD Jr, Frederic Mushinski J. (2007...between: Pearson : p-value PTEN and ETS2-P (T72) -0.577 < 0.001 PTEN and AKT-P (S473) -0.552 < 0.001 ETS2-P (T72) and AKT-P (S473) 0.947 < 0.001 50μm

  4. Pten Regulates Epithelial Cytodifferentiation during Prostate Development.

    Directory of Open Access Journals (Sweden)

    Isabel B Lokody

    Full Text Available Gene expression and functional studies have indicated that the molecular programmes involved in prostate development are also active in prostate cancer. PTEN has been implicated in human prostate cancer and is frequently mutated in this disease. Here, using the Nkx3.1:Cre mouse strain and a genetic deletion approach, we investigate the role of Pten specifically in the developing mouse prostate epithelia. In contrast to its role in other developing organs, this gene is dispensable for the initial developmental processes such as budding and branching. However, as cytodifferentiation progresses, abnormal luminal cells fill the ductal lumens together with augmented epithelial proliferation. This phenotype resembles the hyperplasia seen in postnatal Pten deletion models that develop neoplasia at later stages. Consistent with this, gene expression analysis showed a number of genes affected that are shared with Pten mutant prostate cancer models, including a decrease in androgen receptor regulated genes. In depth analysis of the phenotype of these mice during development revealed that loss of Pten leads to the precocious differentiation of epithelial cells towards a luminal cell fate. This study provides novel insight into the role of Pten in prostate development as part of the process of coordinating the differentiation and proliferation of cell types in time and space to form a functional organ.

  5. Pten Regulates Epithelial Cytodifferentiation during Prostate Development

    Science.gov (United States)

    Lokody, Isabel B.; Francis, Jeffrey C.; Gardiner, Jennifer R.; Erler, Janine T.; Swain, Amanda

    2015-01-01

    Gene expression and functional studies have indicated that the molecular programmes involved in prostate development are also active in prostate cancer. PTEN has been implicated in human prostate cancer and is frequently mutated in this disease. Here, using the Nkx3.1:Cre mouse strain and a genetic deletion approach, we investigate the role of Pten specifically in the developing mouse prostate epithelia. In contrast to its role in other developing organs, this gene is dispensable for the initial developmental processes such as budding and branching. However, as cytodifferentiation progresses, abnormal luminal cells fill the ductal lumens together with augmented epithelial proliferation. This phenotype resembles the hyperplasia seen in postnatal Pten deletion models that develop neoplasia at later stages. Consistent with this, gene expression analysis showed a number of genes affected that are shared with Pten mutant prostate cancer models, including a decrease in androgen receptor regulated genes. In depth analysis of the phenotype of these mice during development revealed that loss of Pten leads to the precocious differentiation of epithelial cells towards a luminal cell fate. This study provides novel insight into the role of Pten in prostate development as part of the process of coordinating the differentiation and proliferation of cell types in time and space to form a functional organ. PMID:26076167

  6. PTEN expression in patients with carcinoma of the cervix and its association with p53, Ki-67 and CD31

    OpenAIRE

    2014-01-01

    PURPOSE: To investigate protein expression and mutations in phosphatase and tensin homolog (PTEN) in patients with stage IB cervical squamous cell carcinoma (CSCC) and the association with clinical-pathologic features, tumor p53 expression, cell proliferation and angiogenesis.METHODS:Women with stage IB CSCC (n=20 - Study Group) and uterine myoma (n=20 - Control Group), aged 49.1±1.7 years (mean±standard deviation, range 27-78 years), were prospectively evaluated. Patients with cervical cance...

  7. Loss of Phosphatase and tensin homologue deleted on chromosome 10 engages ErbB3 and IGF-IR signaling to promote antiestrogen resistance in breast cancer

    Science.gov (United States)

    Miller, Todd W.; Pérez-Torres, Marianela; Narasanna, Archana; Guix, Marta; Stål, Olle; Pérez-Tenorio, Gizeh; Gonzalez-Angulo, Ana M.; Hennessy, Bryan T.; Mills, Gordon B.; Kennedy, J. Phillip; Lindsley, Craig W.; Arteaga, Carlos L.

    2009-01-01

    Knockdown of the tumor suppressor phosphatase PTEN with shRNA in three estrogen receptor (ER)-positive breast cancer cell lines resulted in increased PI3K and AKT activities, resistance to tamoxifen and fulvestrant, and hormone-independent growth. PTEN knockdown induced the upregulation of ER transcriptional activity in MCF-7 cells, but decreased ER protein levels and transcriptional activity in T47D and MDA-361 cells. Tamoxifen and fulvestrant treatment inhibited estradiol-induced ER transcriptional activity in all shPTEN cell lines but did not abrogate the increased cell proliferation induced by PTEN knockdown. PTEN knockdown increased basal and ligand-induced activation of the IGF-I and ErbB3 receptor tyrosine kinases, and prolonged the association of the p85 PI3K subunit with the IGF-IR effector IRS-1 and with ErbB3, implicating PTEN in the modulation of signaling upstream of PI3K. Consistent with these data, PTEN levels inversely correlated with levels of tyrosine-phosphorylated IGF-IR in tissue lysate arrays of primary breast cancers. Inhibition of IGF-IR and/or ErbB2-mediated activation of ErbB3 with tyrosine kinase inhibitors restored hormone-dependence and the growth inhibitory effect of tamoxifen and fulvestrant on shPTEN cells, suggesting that co-targeting both ER and receptor tyrosine kinase pathways holds promise for the treatment of patients with ER+, PTEN-deficient breast cancers. PMID:19435893

  8. Role of PTEN in TNFα induced insulin resistance

    Energy Technology Data Exchange (ETDEWEB)

    Bulger, David A. [Departments of Medicine and Pharmacology, University of Tennessee Health Science Center, Memphis, TN 38163 (United States); Medicine and Research Services, Veterans Association Medical Center, Memphis, TN 38104 (United States); Wellcome Trust Medical Research Council Institute of Metabolic Science, Cambridge CB2 0QQ (United Kingdom); National Institute of Diabetes & Digestive & Kidney Disease, National Institutes of Health, Bethesda, MD 20892 (United States); Conley, Jermaine [Medicine and Research Services, Veterans Association Medical Center, Memphis, TN 38104 (United States); Conner, Spencer H.; Majumdar, Gipsy [Departments of Medicine and Pharmacology, University of Tennessee Health Science Center, Memphis, TN 38163 (United States); Medicine and Research Services, Veterans Association Medical Center, Memphis, TN 38104 (United States); Solomon, Solomon S., E-mail: ssolomon@uthsc.edu [Departments of Medicine and Pharmacology, University of Tennessee Health Science Center, Memphis, TN 38163 (United States); Medicine and Research Services, Veterans Association Medical Center, Memphis, TN 38104 (United States)

    2015-06-05

    Aims/hypothesis: PTEN may play a reversible role in TNFα induced insulin resistance, which has been linked to obesity-associated insulin resistance (IR). Methods: Western blots for PTEN and p-Akt were performed on H-411E liver cells incubated with insulin, TNFα, and in selected experiments VO-OHpic vanadium complex in the presence and absence of PTEN siRNA. Total PTEN was compared to β-actin loading control and p-Akt was compared to total Akt. Results: Western blot and Real Time RT-PCR experiments showed increased PTEN after TNFα treatment (p = 0.04); slightly decreased PTEN after insulin treatment; and slightly increased PTEN after insulin + TNFα treatment. PTEN siRNA markedly inhibited the TNFα-induced increase in PTEN (p < 0.01) without significantly changing the p-Akt levels. The vanadium complex, exhibiting insulin-like effects, also significantly prevented the TNFα-induced increase in PTEN. Combining insulin and VO-OHpic was additive, providing both proof of concept and insight into mechanism. Discussion: The PTEN increase due to TNFα treatment was reversible by both PTEN siRNA knockdown and VO-OHpic treatment. Thus, PTEN is identified as a potential new therapeutic target for reducing IR in Type 2 DM. - Highlights: • TNFα treatment induced a significant increase in PTEN in H-411E liver cells. • PTEN siRNA knockdown prevented this effect. • VO-OHpic (vanadium complex) treatment, like insulin, decreased PTEN protein levels. • Thus, PTEN is identified as a potential therapeutic target in DM Type 2.

  9. PTEN gene mutations correlate to poor prognosis in glioma patients: a meta-analysis

    Directory of Open Access Journals (Sweden)

    Han F

    2016-06-01

    Full Text Available Feng Han,1,* Rong Hu,2,* Hua Yang,1 Jian Liu,1 Jianmei Sui,1 Xin Xiang,1 Fan Wang,1 Liangzhao Chu,1 Shibin Song1 1Department of Neurosurgery, Affiliated Hospital of Guizhou Medical University, 2Department of Histology and Embryology, College of Basic Medical Sciences, Guizhou Medical University, Guiyang, Guizhou, People’s Republic of China *These authors contributed equally to this work Background: We conducted this meta-analysis based on eligible trials to investigate the relationship between phosphatase and tensin homolog (PTEN genetic mutation and glioma patients’ survival. Methods: PubMed, Web of Science, and EMBASE were searched for eligible studies regarding the relationship between PTEN genetic mutation and glioma patients’ survival. The primary outcome was the overall survival of glioma patient with or without PTEN genetic mutation, and second outcome was prognostic factors for the survival of glioma patient. A fixed-effects or random-effects model was used to pool the estimates according to the heterogeneity among the included studies. Results: Nine cohort studies, involving 1,173 patients, were included in this meta-analysis. Pooled results suggested that glioma patients with PTEN genetic mutation had a significant shorter overall survival than those without PTEN genetic mutation (hazard ratio [HR] =2.23, 95% confidence interval [CI]: 1.35, 3.67; P=0.002. Furthermore, subgroup analysis indicated that this association was only observed in American patients (HR =2.19, 95% CI: 1.23, 3.89; P=0.008, but not in Chinese patients (HR =1.44, 95% CI: 0.29, 7.26; P=0.657. Histopathological grade (HR =1.42, 95% CI: 0.07, 28.41; P=0.818, age (HR =0.94, 95% CI: 0.43, 2.04; P=0.877, and sex (HR =1.28, 95% CI: 0.55, 2.98; P=0.564 were not significant prognostic factors for the survival of patients with glioma. Conclusion: Current evidence indicates that PTEN genetic mutation is associated with poor prognosis in glioma patients. However, this

  10. Association of Tat with promoters of PTEN and PP2A subunits is key to transcriptional activation of apoptotic pathways in HIV-infected CD4+ T cells.

    Directory of Open Access Journals (Sweden)

    Nayoung Kim

    2010-09-01

    Full Text Available Apoptosis in HIV-1-infected CD4+ primary T cells is triggered by the alteration of the PI3K and p53 pathways, which converge on the FOXO3a transcriptional activator. Tat alone can cause activation of FOXO3a and of its proapoptotic target genes. To understand how Tat affects this pathway, we carried out ChIP-Chip experiments with Tat. Tat associates with the promoters of PTEN and two PP2A subunit genes, but not with the FOXO3a promoter. PTEN and PP2A encode phosphatases, whose levels and activity are increased when Tat is expressed. They counteract phosphorylation of Akt1 and FOXO3a, and so activate transcriptional activity of FOXO3a. FOXO3a promotes increased transcription of Egr-1, which can further stimulate the transcription of PTEN, thereby reinforcing the pathway that leads to FOXO3a transcriptional activation. RNAi experiments support the role of PTEN and PP2A in the initiation of the Tat-mediated cascade, which is critical to apoptosis. The increased accumulation of PTEN and PP2A subunit mRNAs during Tat expression is more likely to be the result of increased transcription initiation and not relief of promoter-proximal pausing of RNAPII. The Tat-PTEN and -PP2A promoter interactions provide a mechanistic explanation of Tat-mediated apoptosis in CD4+ T cells.

  11. Construction and identification of the PTEN expression plasmid GFP-PTEN%PTEN基因真核表达载体的构建及在MG63中表达

    Institute of Scientific and Technical Information of China (English)

    徐生林; 胡勇; 金问森; 王明明; 王京; 王娟

    2012-01-01

    目的 构建PTEN基因真核表达载体,为PTEN基因功能研究提供工具.方法 从人淋巴细胞中提取总RNA,采用反转录-聚合酶链反应扩增PTEN基因编码区,将其克隆入pEGFP-N1载体中.通过聚合酶链反应、酶切和DNA测序鉴定所构建的载体.脂质体包裹重组载体转染骨肉瘤MG63细胞,RT-PCR和Western blot检测转染后的骨肉瘤MG63细胞中PTEN基因mRNA和蛋白质表达情况.结果 经过限制性酶切和测序鉴定得到重组子GFP-PTEN大小符合,序列与GenBank中人DNA的PTEN基因(NM_000314)完全一致.转染GFP-PTEN基因的骨肉瘤MG63细胞中PTEN基因mRNA和蛋白高水平表达.结论 成功地构建了PTEN基因真核表达载体.%Objective To construct an eukaryotic expression vector for phosphatase and tensin homology deletedon chromosome ten( PTEN ) gene lymphocytes and provide a tool for studying of PTEN gene function. Methods The total RNAs were isolated from human lymphocytes. The cDNA of PTEN gene was amplified by reverse transcription polymerase chain reaction( RT-PCR ). After purification, the gene was cloned into pEGFP-Nl vector. The recombi-nant plasmid was identified by enzyme digestion and DNA sequencing. Then GFP and GFP-PTEN were respectively transfected into the osteosaocoma cell line( MG63 )with Lipofectamine 2000. The mRNA and protein expression level of PTEN gene in each cell group was detected by fluorescent quantitative RT-PCR and Western blot. Results Re-combinant vector of GFP-PTEN was constructed successfully. After transfection with GFP-PTEN, the mRNA and protein expression level of PTEN rose in MG63 cells. There were significant differences between transfected group and control group. Conclusion The eukaryotic expression vector of PTEN gene has been successfully constructed, which may provide a basis for further researches.

  12. Inhibition of transfected PTEN on human colon cancer

    Institute of Scientific and Technical Information of China (English)

    Shou-Shui Xu; Wen-Lu Shen; Song-Ying Ouyang

    2004-01-01

    AIM: To study the inhibitory effect of transfected PTEN on LoVo cells.METHODS: Human PTEN cDNA was transferred into LoVo cells via lipofectin and PTEN mRNA levels and its expression were analyzed by Western blot and flow cytometry. Before or after transfection, the effects of 5-Fu on inhibiting cell proliferation and inducing apoptosis were measured by flow cytometry, DNA bands and MTT.RESULTS: PTEN transfection significantly up-regulated PTEN expression in LoVo cells. 5-Fu inhibited cell proliferation and induced apoptosis in transfected LoVo cells.CONCLUSION: Transfected PTEN can remark ably up-regulate PTEN expression in LoVo cells and promote the apoptosis.PTEN transfection is associated with 5-Fu treatment effect and has a cooperatively cytotoxic effect.

  13. Subtle variations in Pten dose determine cancer susceptibility.

    Science.gov (United States)

    Alimonti, Andrea; Carracedo, Arkaitz; Clohessy, John G; Trotman, Lloyd C; Nardella, Caterina; Egia, Ainara; Salmena, Leonardo; Sampieri, Katia; Haveman, William J; Brogi, Edi; Richardson, Andrea L; Zhang, Jiangwen; Pandolfi, Pier Paolo

    2010-05-01

    Cancer susceptibility has been attributed to at least one heterozygous genetic alteration in a tumor suppressor gene (TSG). It has been hypothesized that subtle variations in TSG expression can promote cancer development. However, this hypothesis has not yet been definitively supported in vivo. Pten is a TSG frequently lost in human cancer and mutated in inherited cancer-predisposition syndromes. Here we analyze Pten hypermorphic mice (Pten(hy/+)), expressing 80% normal levels of Pten. Pten(hy/+) mice develop a spectrum of tumors, with breast tumors occurring at the highest penetrance. All breast tumors analyzed here retained two intact copies of Pten and maintained Pten levels above heterozygosity. Notably, subtle downregulation of Pten altered the steady-state biology of the mammary tissues and the expression profiles of genes involved in cancer cell proliferation. We present an alterative working model for cancer development in which subtle reductions in the dose of TSGs predispose to tumorigenesis in a tissue-specific manner.

  14. Electric field-induced suppression of PTEN drives epithelial-to-mesenchymal transition via mTORC1 activation.

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    Yan, Tiantian; Jiang, Xupin; Guo, Xiaowei; Chen, Wen; Tang, Di; Zhang, Junhui; Zhang, Xingyue; Zhang, Dongxia; Zhang, Qiong; Jia, Jiezhi; Huang, Yuesheng

    2017-02-01

    Naturally occurring electric fields (EFs) are an intrinsic property of wounds. Endogenous EFs in skin wounds play critical roles in the dynamic and well-ordered biological process of wound healing. The epithelial-to-mesenchymal transition (EMT) allows keratinocytes to transition from sedentary cells to motile cells, facilitating wound healing. However, EMT-related studies have been performed without considering endogenous EFs. Thus, the relationship between electrical signals and the EMT remain elusive. Phosphatase and tension homolog (PTEN) and mammalian target of rapamycin complex 1 (mTORC1) are key molecules in sensing electrical cues, and they play significant roles in cellular responses to EFs. In addition, these molecules are closely related to the occurrence of the EMT in other cells. We used primary human keratinocytes to investigate the influence of EFs on the EMT as well as the roles of PTEN and mTORC1 in this process. The effects of EFs on the EMT were investigated by analyzing the levels of specific proteins and transcription factors. The roles of mTORC1 and PTEN and their relationship with each other were studied via pharmacological inhibition or genetic knockdown. A Zeiss imaging system and scratch assays were used to study single-cell motility and monolayer cell migration. EFs induced a range of both biochemical changes (e.g., increased Snail, Slug, vimentin, and N-cadherin expression, decreased E-cadherin expression) and functional changes (e.g., enhanced migratory capacity) that are characteristic of the EMT. EF-stimulated cells exhibited suppressed PTEN expression, and further PTEN downregulation led to the acquisition of more mesenchymal features and the loss of epithelial characteristics, which was accompanied by increased migratory capacity. PTEN overexpression reversed the EF-induced EMT and inhibited the migratory capacity of keratinocytes. EF-induced mTORC1 activation was a required component of the causal relationship between PTEN

  15. EXPRESSION AND SIGNIFICANCE OF PTEN IN ENDOMETRIAL CARCINOMA

    Institute of Scientific and Technical Information of China (English)

    GE Xiu-jun; LIU Zhi-hui; LI Ying-yong; Gao Rui-ping

    2005-01-01

    Objective: To investigate the expression of PTEN in endometrial carcinoma and its clinical significance. Methods: Reverse transcriptase-polymerase chain reaction and Western-blot methods were used to detect PTEN expression in 28 cases of endometrial carcinoma. Results: mRNA and protein expression levels of PTEN in endometrial carcinomas were significantly lower than those in normal endometrium (P<0.01). Conclusion: PTEN may play an important role in the tumorigenesis of endometrial carcinoma.

  16. PTEN mosaicism with features of Cowden syndrome.

    Science.gov (United States)

    Gammon, A; Jasperson, K; Pilarski, R; Prior, Tw; Kuwada, S

    2013-12-01

    We present the first known case of somatic PTEN mosaicism causing features of Cowden syndrome (CS) and inheritance in the subsequent generation. A 20-year-old woman presented for genetics evaluation with multiple ganglioneuromas of the colon. On examination, she was found to have a thyroid goiter, macrocephaly, and tongue papules, all suggestive of CS. However, her reported family history was not suspicious for CS. A deleterious PTEN mutation was identified in blood lymphocytes, 966A>G, 967delA. Genetic testing was recommended for her parents. Her 48-year-old father was referred for evaluation and was found to have macrocephaly and a history of Hashimoto's thyroiditis, but no other features of CS. Site-specific genetic testing carried out on blood lymphocytes showed mosaicism for the same PTEN mutation identified in his daughter. Identifying PTEN mosaicism in the proband's father had significant implications for the risk assessment/genetic testing plan for the rest of his family. His result also provides impetus for somatic mosaicism in a parent to be considered when a de novo PTEN mutation is suspected.

  17. Variable laterality of corticospinal tract axons that regenerate after spinal cord injury as a result of PTEN deletion or knock-down.

    Science.gov (United States)

    Willenberg, Rafer; Zukor, Katherine; Liu, Kai; He, Zhigang; Steward, Oswald

    2016-09-01

    Corticospinal tract (CST) axons from one hemisphere normally extend and terminate predominantly in the contralateral spinal cord. We previously showed that deleting the gene phosphatase and tensin homolog (PTEN) in the sensorimotor cortex enables CST axons to regenerate after spinal cord injury and that some regenerating axons extend along the "wrong" side. Here, we characterize the degree of specificity of regrowth in terms of laterality. PTEN was selectively deleted via cortical adeno-associated virus (AAV)-Cre injections in neonatal PTEN-floxed mice. As adults, mice received dorsal hemisection injuries at T12 or complete crush injuries at T9. CST axons from one hemisphere were traced by unilateral biotinylated dextran amine (BDA) injections in PTEN-deleted mice with spinal cord injury and in noninjured PTEN-floxed mice that had not received AAV-Cre. In noninjured mice, 97.9 ± 0.7% of BDA-labeled axons in white matter and 88.5 ± 1.0% of BDA-labeled axons in gray matter were contralateral to the cortex of origin. In contrast, laterality of CST axons that extended past a lesion due to PTEN deletion varied across animals. In some cases, regenerated axons extended predominantly on the ipsilateral side; in other cases, axons extended predominantly contralaterally, and in others, axons were similar in numbers on both sides. Similar results were seen in analyses of cases from previous studies using short hairpin (sh)RNA-mediated PTEN knock-down. These results indicate that CST axons that extend past a lesion due to PTEN deletion or knock-down do not maintain the contralateral rule of the noninjured CST, highlighting one aspect of how the resultant circuitry from regenerating axons may differ from that of the uninjured CST. J. Comp. Neurol. 524:2654-2676, 2016. © 2016 Wiley Periodicals, Inc.

  18. The safe use of a PTEN inhibitor for the activation of dormant mouse primordial follicles and generation of fertilizable eggs.

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    Deepak Adhikari

    Full Text Available BACKGROUND: Primordial ovarian follicles, which are often present in the ovaries of premature ovarian failure (POF patients or are cryopreserved from the ovaries of young cancer patients who are undergoing gonadotoxic anticancer therapies, cannot be used to generate mature oocytes for in vitro fertilization (IVF. There has been very little success in triggering growth of primordial follicles to obtain fertilizable oocytes due to the poor understanding of the biology of primordial follicle activation. METHODOLOGY/PRINCIPAL FINDINGS: We have recently reported that PTEN (phosphatase and tensin homolog deleted on chromosome ten prevents primordial follicle activation in mice, and deletion of Pten from the oocytes of primordial follicles leads to follicular activation. Consequently, the PTEN inhibitor has been successfully used in vitro to activate primordial follicles in both mouse and human ovaries. These results suggest that PTEN inhibitors could be used in ovarian culture medium to trigger the activation of primordial follicle. To study the safety and efficacy of the use of such inhibitors, we activated primordial follicles from neonatal mouse ovaries by transient treatment with a PTEN inhibitor bpV(HOpic. These ovaries were then transplanted under the kidney capsules of recipient mice to generate mature oocytes. The mature oocytes were fertilized in vitro and progeny mice were obtained after embryo transfer. RESULTS AND CONCLUSIONS: Long-term monitoring up to the second generation of progeny mice showed that the mice were reproductively active and were free from any overt signs or symptoms of chronic illnesses. Our results indicate that the use of PTEN inhibitors could be a safe and effective way of generating mature human oocytes for use in novel IVF techniques.

  19. The safe use of a PTEN inhibitor for the activation of dormant mouse primordial follicles and generation of fertilizable eggs.

    Science.gov (United States)

    Adhikari, Deepak; Gorre, Nagaraju; Risal, Sanjiv; Zhao, Zhiyi; Zhang, Hua; Shen, Yan; Liu, Kui

    2012-01-01

    Primordial ovarian follicles, which are often present in the ovaries of premature ovarian failure (POF) patients or are cryopreserved from the ovaries of young cancer patients who are undergoing gonadotoxic anticancer therapies, cannot be used to generate mature oocytes for in vitro fertilization (IVF). There has been very little success in triggering growth of primordial follicles to obtain fertilizable oocytes due to the poor understanding of the biology of primordial follicle activation. We have recently reported that PTEN (phosphatase and tensin homolog deleted on chromosome ten) prevents primordial follicle activation in mice, and deletion of Pten from the oocytes of primordial follicles leads to follicular activation. Consequently, the PTEN inhibitor has been successfully used in vitro to activate primordial follicles in both mouse and human ovaries. These results suggest that PTEN inhibitors could be used in ovarian culture medium to trigger the activation of primordial follicle. To study the safety and efficacy of the use of such inhibitors, we activated primordial follicles from neonatal mouse ovaries by transient treatment with a PTEN inhibitor bpV(HOpic). These ovaries were then transplanted under the kidney capsules of recipient mice to generate mature oocytes. The mature oocytes were fertilized in vitro and progeny mice were obtained after embryo transfer. Long-term monitoring up to the second generation of progeny mice showed that the mice were reproductively active and were free from any overt signs or symptoms of chronic illnesses. Our results indicate that the use of PTEN inhibitors could be a safe and effective way of generating mature human oocytes for use in novel IVF techniques.

  20. Actin dynamics is rapidly regulated by the PTEN and PIP2 signaling pathways leading to myocyte hypertrophy.

    Science.gov (United States)

    Li, Jieli; Tanhehco, Elaine J; Russell, Brenda

    2014-12-01

    Mature cardiac myocytes are terminally differentiated, and the heart has limited capacity to replace lost myocytes. Thus adaptation of myocyte size plays an important role in the determination of cardiac function. The hypothesis tested is that regulation of the dynamic exchange of actin leads to cardiac hypertrophy. ANG II was used as a hypertrophic stimulant in mouse heart and neonatal rat ventricular myocytes (NRVMs) in culture for assessment of a mechanism for regulation of actin dynamics by phosphatidylinositol 4,5-bisphosphate (PIP2). Actin dynamics in NRVMs rapidly increased in a PIP2-dependent manner, measured by imaging and fluorescence recovery after photobleaching (FRAP). A significant increase in PIP2 levels was found by immunoblotting in both adult mouse heart tissue and cultured NRVMs. Inhibition of phosphatase and tensin homolog (PTEN) in NRVMs markedly blunted ANG II-induced increases in actin dynamics, the PIP2 level, and cell size. Furthermore, PTEN activity was dramatically upregulated in ANG II-treated NRVMs but downregulated when PTEN inhibitors were used. The time course of the rise in the PIP2 level was inversely related to the fall in the PIP3 level, which was significant by 30 min in ANG II-treated NRVMs. However, significant translocation of PTEN to the plasma membrane occurred by 10 min, suggesting a crucial initial step for PTEN for the cellular responses to ANG II. In conclusion, PTEN and PIP2 signaling may play an important role in myocyte hypertrophy by the regulation of actin filament dynamics, which is induced by ANG II stimulation. Copyright © 2014 the American Physiological Society.

  1. A functional dissection of PTEN N-terminus : Implications in PTEN subcellular targeting and tumor suppressor activity

    NARCIS (Netherlands)

    Gil, Anabel; Rodríguez-Escudero, Isabel; Stumpf, Miriam; Molina, María; Cid, Víctor J.; Pulido, Rafael

    2015-01-01

    Spatial regulation of the tumor suppressor PTEN is exerted through alternative plasma membrane, cytoplasmic, and nuclear subcellular locations. The N-terminal region of PTEN is important for the control of PTEN subcellular localization and function. It contains both an active nuclear localization

  2. Matrine Activates PTEN to Induce Growth Inhibition and Apoptosis in V600EBRAF Harboring Melanoma Cells

    Directory of Open Access Journals (Sweden)

    Shuiying Wang

    2013-07-01

    Full Text Available Here, we report a natural chemical Matrine, which exhibits anti-melanoma potential with its PTEN activation mechanism. Matrine effectively inhibited proliferation of several carcinoma cell lines, including melanoma V600EBRAF harboring M21 cells. Flow cytometry analysis showed Matrine induced G0/G1 cell cycle arrest in M21 cells dose-dependently. Apoptosis in M21 cells induced by Matrine was identified by Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL analysis and Annexin-V/FITC staining. Molecular mechanistic study suggested that Matrine upregulated both mRNA level and protein expression level of phosphatase and tensin homolog deleted on chromosome ten (PTEN, leading to inhibition of the PI3K/Akt pathway. Downregulation of phosphor-Aktser473 by Matrine activated p21 and Bax, which contributed to G0/G1 cell cycle and apoptosis. Besides, Matrine enhanced the PI3K/Akt inhibition effects to inhibit the cell proliferation with PI3K inhibitor, LY2940002. In summary, our findings suggest Matrine is a promising antitumor drug candidate with its possible PTEN activation mechanisms for treating cancer diseases, such as melanomas.

  3. Analysis of Phosphatidylinositol 3,4,5-Trisphosphates of PTEN Expression on Mammalian Cells

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    Nusrat Jahan

    2013-09-01

    Full Text Available The goal of this study is to find an experimental condition which enables us to perform enzymatic studies on the cellular behavior of PTEN (phosphatase and tensine homolog through identification of molecular species of phosphatidylinositol 3,4,5- trisphosphates and their quantitative analysis in a mammalian cell line using mass spectrometry. We initially exployed a two-step extraction process using HCl for extraction of phosphatidylinositol 3,4,5-trisphosphates from two mammalian cell lines and further analyzed the extracted phosphatidylinositol 3,4,5-trisphosphates using tandem mass spectrometry for the identification of them. We finally quantified the concentration of phosphatidylinositol 3,4,5-trisphosphates using internal standard calibration. From these observation, we found that HEK 293-T cells is a good model to examine the enzymatic behavior of PTEN in a cell, and the minimum amount of phosphatidylinositol 3,4,5-trisphosphates is more than 50 pmol for quantification in a mass spectrometer. These results suggest that the well-optimized experimental conditions are required for the investigation of the cellular PTEN in terms of the catalytic mechanism and further for the detailed identification of cellular substrates

  4. PTEN基因与皮肤肿瘤%PTEN gene and skin cancer

    Institute of Scientific and Technical Information of China (English)

    郭泽; 周炳荣; 李巍; 骆丹

    2011-01-01

    皮肤肿瘤是一类最常见的肿瘤,在引起皮肤肿瘤发生的诸多原因中,紫外线照射是主要影响因素之一。PTEN是近年来研究较多的一个肿瘤抑制基因,位于染色体10q23,3。目前研究证实,PTEN在多种皮肤肿瘤,如基底细胞癌、鳞状细胞癌、恶性黑素瘤中都起着抑制基因的作用,发现在皮肤肿瘤形成过程中,紫外线照射可引起PTEN失活,对肿瘤的形成可能起着促进的作用。%Skin cancer is one of the most common cancers. Ultraviolet irradiation is the predominant environmental factor causing skin cancer. Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a tumor suppressor gene located on chromosome 10 q23,3, which has been frequently studied in recent years. There is evidence that PTEN acts as a tumor suppressor in many skin cancers, such as basal cell carcinoma, squamous cell carcinoma, and melanoma. Ultraviolet irradiation can result in the inactivation of PTEN and in turn promote the development of cancer.

  5. Early Behavioral Abnormalities and Perinatal Alterations of PTEN/AKT Pathway in Valproic Acid Autism Model Mice.

    Science.gov (United States)

    Yang, Eun-Jeong; Ahn, Sangzin; Lee, Kihwan; Mahmood, Usman; Kim, Hye-Sun

    2016-01-01

    Exposure to valproic acid (VPA) during pregnancy has been linked with increased incidence of autism, and has repeatedly been demonstrated as a useful autism mouse model. We examined the early behavioral and anatomical changes as well as molecular changes in mice prenatally exposed to VPA (VPA mice). In this study, we first showed that VPA mice showed developmental delays as assessed with self-righting, eye opening tests and impaired social recognition. In addition, we provide the first evidence that primary cultured neurons from VPA-treated embryos present an increase in dendritic spines, compared with those from control mice. Mutations in phosphatase and tensin homolog (PTEN) gene are also known to be associated with autism, and mice with PTEN knockout show autistic characteristics. Protein expression of PTEN was decreased and the ratio of p-AKT/AKT was increased in the cerebral cortex and the hippocampus, and a distinctive anatomical change in the CA1 region of the hippocampus was observed. Taken together, our study suggests that prenatal exposure to VPA induces developmental delays and neuroanatomical changes via the reduction of PTEN level and these changes were detectable in the early days of life.

  6. Redox signaling via oxidative inactivation of PTEN modulates pressure-dependent myogenic tone in rat middle cerebral arteries.

    Directory of Open Access Journals (Sweden)

    Debebe Gebremedhin

    Full Text Available The present study examined the level of generation of reactive oxygen species (ROS and roles of inactivation of the phosphatase PTEN and the PI3K/Akt signaling pathway in response to an increase in intramural pressure-induced myogenic cerebral arterial constriction. Step increases in intraluminal pressure of cannulated cerebral arteries induced myogenic constriction and concomitant formation of superoxide (O2 (.- and its dismutation product hydrogen peroxide (H2O2 as determined by fluorescent HPLC analysis, microscopic analysis of intensity of dihydroethidium fluorescence and attenuation of pressure-induced myogenic constriction by pretreatment with the ROS scavenger 4,hydroxyl-2,2,6,6-tetramethylpiperidine1-oxyl (tempol or Mito-tempol or MitoQ in the presence or absence of PEG-catalase. An increase in intraluminal pressure induced oxidation of PTEN and activation of Akt. Pharmacological inhibition of endogenous PTEN activity potentiated pressure-dependent myogenic constriction and caused a reduction in NPo of a 238 pS arterial KCa channel current and an increase in [Ca(2+]i level in freshly isolated cerebral arterial muscle cells (CAMCs, responses that were attenuated by Inhibition of the PI3K/Akt pathway. These findings demonstrate an increase in intraluminal pressure induced increase in ROS production triggered redox-sensitive signaling mechanism emanating from the cross-talk between oxidative inactivation of PTEN and activation of the PI3K/Akt signaling pathway that involves in the regulation of pressure-dependent myogenic cerebral arterial constriction.

  7. MicroRNA-22 promotes cell survival upon UV radiation by repressing PTEN

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Guangyun [Department of Pathology and Laboratory Medicine, University of Tennessee Health Science Center, Memphis, TN (United States); Center for Adult Cancer Research, University of Tennessee Health Science Center, Memphis, TN (United States); Jilin Province Key Laboratory of Animal Embryo Engineering, Jilin University, Changchun (China); Shi, Yuling [Department of Pathology and Laboratory Medicine, University of Tennessee Health Science Center, Memphis, TN (United States); Center for Adult Cancer Research, University of Tennessee Health Science Center, Memphis, TN (United States); Wu, Zhao-Hui, E-mail: zwu6@uthsc.edu [Department of Pathology and Laboratory Medicine, University of Tennessee Health Science Center, Memphis, TN (United States); Center for Adult Cancer Research, University of Tennessee Health Science Center, Memphis, TN (United States)

    2012-01-06

    Highlights: Black-Right-Pointing-Pointer miR-22 is induced in cells treated with UV radiation. Black-Right-Pointing-Pointer ATM is required for miR-22 induction in response to UV. Black-Right-Pointing-Pointer miR-22 targets 3 Prime -UTR of PTEN to repress its expression in UV-treated cells. Black-Right-Pointing-Pointer Upregulated miR-22 inhibits apoptosis in cells exposed to UV. -- Abstract: DNA damage response upon UV radiation involves a complex network of cellular events required for maintaining the homeostasis and restoring genomic stability of the cells. As a new class of players involved in DNA damage response, the regulation and function of microRNAs in response to UV remain poorly understood. Here we show that UV radiation induces a significant increase of miR-22 expression, which appears to be dependent on the activation of DNA damage responding kinase ATM (ataxia telangiectasia mutated). Increased miR-22 expression may result from enhanced miR-22 maturation in cells exposed to UV. We further found that tumor suppressor gene phosphatase and tensin homolog (PTEN) expression was inversely correlated with miR-22 induction and UV-induced PTEN repression was attenuated by overexpression of a miR-22 inhibitor. Moreover, increased miR-22 expression significantly inhibited the activation of caspase signaling cascade, leading to enhanced cell survival upon UV radiation. Collectively, these results indicate that miR-22 is an important player in the cellular stress response upon UV radiation, which may promote cell survival via the repression of PTEN expression.

  8. Calpain-2-mediated PTEN degradation contributes to BDNF-induced stimulation of dendritic protein synthesis.

    Science.gov (United States)

    Briz, Victor; Hsu, Yu-Tien; Li, Yi; Lee, Erin; Bi, Xiaoning; Baudry, Michel

    2013-03-06

    Memory consolidation has been suggested to be protein synthesis dependent. Previous data indicate that BDNF-induced dendritic protein synthesis is a key event in memory formation through activation of the mammalian target of rapamycin (mTOR) pathway. BDNF also activates calpain, a calcium-dependent cysteine protease, which has been shown to play a critical role in learning and memory. This study was therefore directed at testing the hypothesis that calpain activity is required for BDNF-stimulated local protein synthesis, and at identifying the underlying molecular mechanism. In rat hippocampal slices, cortical synaptoneurosomes, and cultured neurons, BDNF-induced mTOR pathway activation and protein translation were blocked by calpain inhibition. BDNF treatment rapidly reduced levels of hamartin and tuberin, negative regulators of mTOR, in a calpain-dependent manner. Treatment of brain homogenates with purified calpain-1 and calpain-2 truncated both proteins. BDNF treatment increased phosphorylation of both Akt and ERK, but only the effect on Akt was blocked by calpain inhibition. Levels of phosphatase and tensin homolog deleted on chromosome 10 (PTEN), a phosphatase that inactivates Akt, were decreased following BDNF treatment, and calpain inhibition reversed this effect. Calpain-2, but not calpain-1, treatment of brain homogenates resulted in PTEN degradation. In cultured cortical neurons, knockdown of calpain-2, but not calpain-1, by small interfering RNA completely suppressed the effect of BDNF on mTOR activation. Our results reveal a critical role for calpain-2 in BDNF-induced mTOR signaling and dendritic protein synthesis via PTEN, hamartin, and tuberin degradation. This mechanism therefore provides a link between proteolysis and protein synthesis that might contribute to synaptic plasticity.

  9. The Membrane and Lipids as Integral Participants in Signal Transduction: Lipid Signal Transduction for the Non-Lipid Biochemist

    Science.gov (United States)

    Eyster, Kathleen M.

    2007-01-01

    Reviews of signal transduction have often focused on the cascades of protein kinases and protein phosphatases and their cytoplasmic substrates that become activated in response to extracellular signals. Lipids, lipid kinases, and lipid phosphatases have not received the same amount of attention as proteins in studies of signal transduction.…

  10. Crystal Structure of Phosphatidylglycerophosphatase (PGPase), a Putative Membrane-Bound Lipid Phosphatase, Reveals a Novel Binuclear Metal Binding Site and Two Proton Wires

    Energy Technology Data Exchange (ETDEWEB)

    Kumaran,D.; Bonnano, J.; Burley, S.; Swaminathan, S.

    2006-01-01

    Phosphatidylglycerophosphatase (PGPase), an enzyme involved in lipid metabolism, catalyzes formation of phosphatidylglycerol from phosphatidylglycerophosphate. Phosphatidylglycerol is a multifunctional phospholipid, found in the biological membranes of many organisms. Here, we report the crystal structure of Listeria monocytogenes PGPase at 1.8 Angstroms resolution. PGPase, an all-helical molecule, forms a homotetramer. Each protomer contains an independent active site with two metal ions, Ca{sup 2+} and Mg{sup 2+}, forming a hetero-binuclear center located in a hydrophilic cavity near the surface of the molecule. The binuclear center, conserved ligands, metal-bound water molecules, and an Asp-His dyad form the active site. The catalytic mechanism of this enzyme is likely to proceed via binuclear metal activated nucleophilic water. The binuclear metal-binding active-site environment of this structure should provide insights into substrate binding and metal-dependent catalysis. A long channel with inter-linked linear water chains, termed 'proton wires', is observed at the tetramer interface. Comparison of similar water chain structures in photosynthetic reaction centers (RCs), Cytochrome f, gramicidin, and bacteriorhodopsin, suggests that PGPase may conduct protons via proton wires.

  11. Transforming growth factor-beta1 upregulation triggers pulmonary artery smooth muscle cell proliferation and apoptosis imbalance in rats with hypoxic pulmonary hypertension via the PTEN/AKT pathways.

    Science.gov (United States)

    Liu, Yun; Cao, Yonggang; Sun, Shuyang; Zhu, Jinquan; Gao, Shan; Pang, Jie; Zhu, Daling; Sun, Zengxian

    2016-08-01

    Transforming growth factor-beta1 (TGFβ1) and Phosphatase and Tensin homolog deleted on chromosome ten (PTEN) are involved in the regulation of proliferation, differentiation, migration and apoptosis of various cell types. In previous studies, we have shown that TGFβ1 and PTEN play an important role in the progression of pulmonary vascular remodeling induced by pulmonary artery smooth muscle cells (PASMCs). However, the mechanisms involved in the activation of PASMCs between TGFβ1 and PTEN pathways remain unknown. We found that pulmonary vascular walls in hypoxic pulmonary arterial hypertension (PAH) rats were thicker than the vessels from normal rats in vivo. Substantially higher levels of TGFβ1 and significant loss of PTEN expression were observed in the lungs of PAH rats when compared with normoxia. Meanwhile, AKT, a downstream proliferative signaling protein of the PTEN antagonist PI3K, was markedly activated in the lungs of PAH rats. In vitro studies using PASMCs showed that TGFβ1 increased cell proliferation in PTEN-dependent manner. Moreover, we found that TGFβ1 enhanced cell survival, up-regulated the expression of Bcl-2 and procaspase-3, decreased the number of TUNEL-positive cells and caspase-3 expression in PASMCs under serum-deprived (SD) condition via PI3K/AKT pathway. The results further establish that TGFβ1 promoted PAH by decreasing PTEN expression and increasing PI3K/AKT activation in the lung. In conclusion, TGFβ1 mediated PTEN inactivation and resistance to apoptosis seems to be key mediators of lung vascular remodeling associated with PAH. These findings further clarify molecular mechanisms that support targeting PTEN/AKT signaling pathway to attenuate pathogenic derangements in PAH.

  12. Impaired Pten expression in human malignant peripheral nerve sheath tumours.

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    Maren Bradtmöller

    Full Text Available Malignant peripheral nerve sheath tumours (MPNST are aggressive sarcomas that develop in about 10% of patients with the genetic disease neurofibromatosis type 1 (NF1. Molecular alterations contributing to MPNST formation have only partially been resolved. Here we examined the role of Pten, a key regulator of the Pi3k/Akt/mTOR pathway, in human MPNST and benign neurofibromas. Immunohistochemistry showed that Pten expression was significantly lower in MPNST (n=16 than in neurofibromas (n=16 and normal nervous tissue. To elucidate potential mechanisms for Pten down-regulation or Akt/mTOR activation in MPNST we performed further experiments. Mutation analysis revealed absence of somatic mutations in PTEN (n=31 and PIK3CA (n=38. However, we found frequent PTEN promotor methylation in primary MPNST (11/26 and MPNST cell lines (7/8 but not in benign nerve sheath tumours. PTEN methylation was significantly associated with early metastasis. Moreover, we detected an inverse correlation of Pten-regulating miR-21 and Pten protein levels in MPNST cell lines. The examination of NF1-/- and NF1+/+Schwann cells and fibroblasts showed that Pten expression is not regulated by NF1. To determine the significance of Pten status for treatment with the mTOR inhibitor rapamycin we treated 5 MPNST cell lines with rapamycin. All cell lines were sensitive to rapamycin without a significant correlation to Pten levels. When rapamycin was combined with simvastatin a synergistic anti-proliferative effect was achieved. Taken together we show frequent loss/reduction of Pten expression in MPNST and provide evidence for the involvement of multiple Pten regulating mechanisms.

  13. Salvianolic acid A positively regulates PTEN protein level and inhibits growth of A549 lung cancer cells

    Science.gov (United States)

    BI, LEI; CHEN, JIANPING; YUAN, XIAOJING; JIANG, ZEQUN; CHEN, WEIPING

    2013-01-01

    Salvianolic acid A (Sal A) is an effective compound extracted from Salvia miltiorrhiza which has been used in the treatment of various diseases. Preliminary data indicate that Sal A treatment has a specific anti-lung cancer effect. However, the manner in which Sal A regulates cancer growth remains unknown. In this study, the A549 lung cancer cell line and its response to Sal A treatment was examined. Results showed that Sal A treatment significantly decreased A549 cell growth, promoted partial apoptosis and increased mitochondrial membrane permeability. Western blot analysis showed that Sal A upregulated the phosphatase and tensin homolog (PTEN) protein level, while consistently downregulating Akt phosphorylation. These results indicate that Sal A negatively mediates A549 lung cancer cell line growth or apoptosis, most likely by positively regulating PTEN protein level. PMID:24648921

  14. Cancer cell-oriented migration of mesenchymal stem cells engineered with an anticancer gene (PTEN: an imaging demonstration

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    Yang ZS

    2014-03-01

    Full Text Available Zhuo-Shun Yang,1,* Xiang-Jun Tang,2,* Xing-Rong Guo,1 Dan-Dan Zou,1 Xu-Yong Sun,3 Jing-Bo Feng,1 Jie Luo,1 Long-Jun Dai,1,4 Garth L Warnock4 1Hubei Key Laboratory of Stem Cell Research, Taihe Hospital, Hubei University of Medicine, Shiyan, People’s Republic of China; 2Department of Neurosurgery, Taihe Hospital, Hubei University of Medicine, Shiyan, People’s Republic of China; 3Guangxi Key Laboratory for Transplant Medicine, 303 Hospital of PLA, Nanning, People’s Republic of China; 4Department of Surgery, University of British Columbia, Vancouver, BC, Canada *These authors contributed equally to this work Background: Mesenchymal stem cells (MSCs have been considered to hold great potential as ideal carriers for the delivery of anticancer agents since the discovery of their tumor tropism. This study was performed to demonstrate the effects of phosphatase and tensin homolog (PTEN engineering on MSCs’ capacity for cancer cell-oriented migration. Methods: MSCs were engineered with a PTEN-bearing plasmid and the expression was confirmed with Western blotting. A human glioma cell line (DBTRG was used as the target cell; DBTRG cell-oriented migration of MSCs was monitored with a micro speed photographic system. Results: The expression of transfected PTEN in MSCs was identified by immunoblotting analysis and confirmed with cell viability assessment of target cells. The DBTRG cell-oriented migration of PTEN-engineered MSCs was demonstrated by a real-time dynamic monitoring system, and a phagocytosis-like action of MSCs was also observed. Conclusion: MSCs maintained their capacity for cancer cell-directed migration after they were engineered with anticancer genes. This study provides the first direct evidence of MSCs’ tropism post-anticancer gene engineering. Keywords: gene therapy, mesenchymal stem cells, phosphatase and tensin homolog, cancer

  15. Fish oil suppresses cell growth and metastatic potential by regulating PTEN and NF-κB signaling in colorectal cancer.

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    Shevali Kansal

    Full Text Available Homeostasis in eukaryotic tissues is tightly regulated by an intricate balance of the prosurvival and antisurvival signals. The tumor suppressor PTEN (phosphatase and tensin homolog deleted on chromosome 10, a dual-specificity phosphatase, plays a functional role in cell cycle arrest and apoptosis. NF-κB and its downstream regulators (such as VEGF play a central role in prevention of apoptosis, promotion of inflammation and tumor growth. Therefore, we thought to estimate the expression of PTEN, Poly-ADP-ribose polymerase (PARP, NF-κBp50, NF-κBp65 and VEGF to evaluate the effect of supplementation of fish oil on apoptotic and inflammatory signaling in colon carcinoma. Male wistar rats in Group I received purified diet while Group II and III received modified diet supplemented with FO∶CO(1∶1&FO∶CO(2.5∶1 respectively. These were further subdivided into controls receiving ethylenediamine-tetra acetic-acid and treated groups received dimethylhydrazine-dihydrochloride (DMH/week for 4 weeks. Animals sacrificed 48 hours after last injection constituted initiation phase and that sacrificed after 16 weeks constituted post-initiation phase. We have analysed expression of PTEN, NF-κBp50, NF-κBp65 by flowcytometer and nuclear localization of NF-κB by immunofluorescence. PARP and VEGF were assessed by immunohistochemistry. In the initiation phase, animals receiving DMH have shown increased % of apoptotic cells, PTEN, PARP, NF-κBp50, NF-κBp65 and VEGF however in post-initiation phase no significant alteration in apoptosis with decreased PTEN and increased PARP, NF-κBp50, NF-κBp65 and VEGF were observed as compared to control animals. On treatment with both ratios of fish oil in both the phases, augmentation in % of apoptotic cells, decreased PTEN, PARP, NF-κBp50, NF-κBp65 and VEGF were documented with respect to DMH treated animals with effect being more exerted with higher ration in post-initiation phase. Hence, fish oil activates

  16. PTEN stabilizes TOP2A and regulates the DNA decatenation.

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    Kang, Xi; Song, Chang; Du, Xiao; Zhang, Cong; Liu, Yu; Liang, Ling; He, Jinxue; Lamb, Kristy; Shen, Wen H; Yin, Yuxin

    2015-12-10

    PTEN is a powerful tumor suppressor that antagonizes the cytoplasmic PI3K-AKT pathway and suppresses cellular proliferation. PTEN also plays a role in the maintenance of genomic stability in the nucleus. Here we report that PTEN facilitates DNA decatenation and controls a decatenation checkpoint. Catenations of DNA formed during replication are decatenated by DNA topoisomerase II (TOP2), and this process is actively monitored by a decatenation checkpoint in G2 phase. We found that PTEN deficient cells form ultra-fine bridges (UFBs) during anaphase and these bridges are generated as a result of insufficient decatenation. We show that PTEN is physically associated with a decatenation enzyme TOP2A and that PTEN influences its stability through OTUD3 deubiquitinase. In the presence of PTEN, ubiquitination of TOP2A is inhibited by OTUD3. Deletion or deficiency of PTEN leads to down regulation of TOP2A, dysfunction of the decatenation checkpoint and incomplete DNA decatenation in G2 and M phases. We propose that PTEN controls DNA decatenation to maintain genomic stability and integrity.

  17. PTEN Interacts with Histone H1 and Controls Chromatin Condensation

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    Zhu Hong Chen

    2014-09-01

    Full Text Available Chromatin organization and dynamics are integral to global gene transcription. Histone modification influences chromatin status and gene expression. PTEN plays multiple roles in tumor suppression, development, and metabolism. Here, we report on the interplay of PTEN, histone H1, and chromatin. We show that loss of PTEN leads to dissociation of histone H1 from chromatin and decondensation of chromatin. PTEN deletion also results in elevation of histone H4 acetylation at lysine 16, an epigenetic marker for chromatin activation. We found that PTEN and histone H1 physically interact through their C-terminal domains. Disruption of the PTEN C terminus promotes the chromatin association of MOF acetyltransferase and induces H4K16 acetylation. Hyperacetylation of H4K16 impairs the association of PTEN with histone H1, which constitutes regulatory feedback that may reduce chromatin stability. Our results demonstrate that PTEN controls chromatin condensation, thus influencing gene expression. We propose that PTEN regulates global gene transcription profiling through histones and chromatin remodeling.

  18. Deletion of PTEN produces autism-like behavioral deficits and alterations in synaptic proteins.

    Science.gov (United States)

    Lugo, Joaquin N; Smith, Gregory D; Arbuckle, Erin P; White, Jessika; Holley, Andrew J; Floruta, Crina M; Ahmed, Nowrin; Gomez, Maribel C; Okonkwo, Obi

    2014-01-01

    Many genes have been implicated in the underlying cause of autism but each gene accounts for only a small fraction of those diagnosed with autism. There is increasing evidence that activity-dependent changes in neuronal signaling could act as a convergent mechanism for many of the changes in synaptic proteins. One candidate signaling pathway that may have a critical role in autism is the PI3K/AKT/mTOR pathway. A major regulator of this pathway is the negative repressor phosphatase and tensin homolog (PTEN). In the current study we examined the behavioral and molecular consequences in mice with neuron subset-specific deletion of PTEN. The knockout (KO) mice showed deficits in social chamber and social partition test. KO mice demonstrated alterations in repetitive behavior, as measured in the marble burying test and hole-board test. They showed no changes in ultrasonic vocalizations emitted on postnatal day 10 or 12 compared to wildtype (WT) mice. They exhibited less anxiety in the elevated-plus maze test and were more active in the open field test compared to WT mice. In addition to the behavioral alterations, KO mice had elevation of phosphorylated AKT, phosphorylated S6, and an increase in S6K. KO mice had a decrease in mGluR but an increase in total and phosphorylated fragile X mental retardation protein. The disruptions in intracellular signaling may be why the KO mice had a decrease in the dendritic potassium channel Kv4.2 and a decrease in the synaptic scaffolding proteins PSD-95 and SAP102. These findings demonstrate that deletion of PTEN results in long-term alterations in social behavior, repetitive behavior, activity, and anxiety. In addition, deletion of PTEN significantly alters mGluR signaling and many synaptic proteins in the hippocampus. Our data demonstrates that deletion of PTEN can result in many of the behavioral features of autism and may provide insights into the regulation of intracellular signaling on synaptic proteins.

  19. Protein kinase A-mediated phosphorylation of Pah1p phosphatidate phosphatase functions in conjunction with the Pho85p-Pho80p and Cdc28p-cyclin B kinases to regulate lipid synthesis in yeast.

    Science.gov (United States)

    Su, Wen-Min; Han, Gil-Soo; Casciano, Jessica; Carman, George M

    2012-09-28

    Pah1p, which functions as phosphatidate phosphatase (PAP) in the yeast Saccharomyces cerevisiae, plays a crucial role in lipid homeostasis by controlling the relative proportions of its substrate phosphatidate and its product diacylglycerol. The diacylglycerol produced by PAP is used for the synthesis of triacylglycerol as well as for the synthesis of phospholipids via the Kennedy pathway. Pah1p is a highly phosphorylated protein in vivo and has been previously shown to be phosphorylated by the protein kinases Pho85p-Pho80p and Cdc28p-cyclin B. In this work, we showed that Pah1p was a bona fide substrate for protein kinase A, and we identified by mass spectrometry and mutagenesis that Ser-10, Ser-677, Ser-773, Ser-774, and Ser-788 were the target sites of phosphorylation. Protein kinase A-mediated phosphorylation of Pah1p inhibited its PAP activity by decreasing catalytic efficiency, and the inhibitory effect was primarily conferred by phosphorylation at Ser-10. Analysis of the S10A and S10D mutations (mimicking dephosphorylation and phosphorylation, respectively), alone or in combination with the seven alanine (7A) mutations of the sites phosphorylated by Pho85p-Pho80p and Cdc28p-cyclin B, indicated that phosphorylation at Ser-10 stabilized Pah1p abundance and inhibited its association with membranes, PAP activity, and triacylglycerol synthesis. The S10A mutation enhanced the physiological effects imparted by the 7A mutations, whereas the S10D mutations attenuated the effects of the 7A mutations. These data indicated that the protein kinase A-mediated phosphorylation of Ser-10 functions in conjunction with the phosphorylations mediated by Pho85p-Pho80p and Cdc28p-cyclin B and that phospho-Ser-10 should be dephosphorylated for proper PAP function.

  20. Involvement of IGF-2, IGF-1R, IGF-2R and PTEN in development of human tooth germ – an immunohistochemical study

    Science.gov (United States)

    Kero, Darko; Cigic, Livia; Medvedec Mikic, Ivana; Galic, Tea; Cubela, Mladen; Vukojevic, Katarina; Saraga-Babic, Mirna

    2016-01-01

    ABSTRACT Insulin-Like Growth Factor 2 (IGF-2) is a peptide hormone essential for prenatal growth and development. IGF-2 exerts its mitogenic effects via Insulin-Like Growth Factor 1 Receptor (IGF-1R), and is eliminated by binding to Insulin-Like Growth Receptor 2 (IGF-2R). IGF-2 is also negatively regulated by Phosphatase and Tensin Homolog (PTEN), a phosphatase mutated in various tumors. Not much is known about the interplay between these factors during human odontogenesis. In this study, expression patterns of IGF-2, IGF-1R, IGF-2R and PTEN were analyzed by double immunofluorescence in incisor human tooth germs during the foetal period of development between the 7th and 20th gestational week. Throughout the investigated period, IGF-2 was mostly expressed in enamel organ, whereas mild to moderate expression of PTEN could be seen in dental papilla and parts of enamel organ. Expression of IGF-1R was ubiquitous and displayed strong intensity throughout the entire enamel organ. In contrast, expression of IGF-2R had rather erratic pattern in enamel organ and dental papilla alike. Expression patterns of IGF-2, IGF-1R, IGF-2R and PTEN in highly proliferative cervical loops, as well as in differentiating pre-ameloblasts and pre-odontoblasts of cusp tip region during the early and late bell stages when enamel organ acquires definitive shape, indicate importance of these factors in crown morphogenesis of human incisor. Taken together, our data suggest the involvement of IGF-2, IGF-1R, IGF-2R and PTEN in temporo-spatial patterning of basic cellular processes (proliferation, differentiation) during normal tooth development. They are also relevant for improving knowledge of molecular basis of human odontogenesis. PMID:27326759

  1. Involvement of IGF-2, IGF-1R, IGF-2R and PTEN in development of human tooth germ - an immunohistochemical study.

    Science.gov (United States)

    Kero, Darko; Cigic, Livia; Medvedec Mikic, Ivana; Galic, Tea; Cubela, Mladen; Vukojevic, Katarina; Saraga-Babic, Mirna

    2016-07-02

    Insulin-Like Growth Factor 2 (IGF-2) is a peptide hormone essential for prenatal growth and development. IGF-2 exerts its mitogenic effects via Insulin-Like Growth Factor 1 Receptor (IGF-1R), and is eliminated by binding to Insulin-Like Growth Receptor 2 (IGF-2R). IGF-2 is also negatively regulated by Phosphatase and Tensin Homolog (PTEN), a phosphatase mutated in various tumors. Not much is known about the interplay between these factors during human odontogenesis. In this study, expression patterns of IGF-2, IGF-1R, IGF-2R and PTEN were analyzed by double immunofluorescence in incisor human tooth germs during the foetal period of development between the 7(th) and 20(th) gestational week. Throughout the investigated period, IGF-2 was mostly expressed in enamel organ, whereas mild to moderate expression of PTEN could be seen in dental papilla and parts of enamel organ. Expression of IGF-1R was ubiquitous and displayed strong intensity throughout the entire enamel organ. In contrast, expression of IGF-2R had rather erratic pattern in enamel organ and dental papilla alike. Expression patterns of IGF-2, IGF-1R, IGF-2R and PTEN in highly proliferative cervical loops, as well as in differentiating pre-ameloblasts and pre-odontoblasts of cusp tip region during the early and late bell stages when enamel organ acquires definitive shape, indicate importance of these factors in crown morphogenesis of human incisor. Taken together, our data suggest the involvement of IGF-2, IGF-1R, IGF-2R and PTEN in temporo-spatial patterning of basic cellular processes (proliferation, differentiation) during normal tooth development. They are also relevant for improving knowledge of molecular basis of human odontogenesis.

  2. Pten function in zebrafish : Anything but a fish story

    NARCIS (Netherlands)

    Stumpf, Miriam; Choorapoikayil, Suma; den Hertog, J.

    2015-01-01

    Zebrafish is an excellent model system for the analysis of gene function. We and others use zebrafish to investigate the function of the tumor suppressor, Pten, in tumorigenesis and embryonic development. Zebrafish have two pten genes, ptena and ptenb. The recently identified N-terminal extension of

  3. PTEN-PDZ domain interactions: Binding of PTEN to PDZ domains of PTPN13.

    NARCIS (Netherlands)

    Sotelo, N.S.; Schepens, J.T.G.; Valiente, M.; Hendriks, W.J.A.J.; Pulido, R.

    2015-01-01

    Protein modular interactions mediated by PDZ domains are essential for the establishment of functional protein networks controlling diverse cellular functions. The tumor suppressor PTEN possesses a C-terminal PDZ-binding motif (PDZ-BM) that is recognized by a specific set of PDZ domains from scaffol

  4. Hepatic stellate cell is activated by microRNA-181b via PTEN/Akt pathway.

    Science.gov (United States)

    Zheng, Jianjian; Wu, Cunzao; Xu, Ziqiang; Xia, Peng; Dong, Peihong; Chen, Bicheng; Yu, Fujun

    2015-01-01

    Activation of hepatic stellate cells (HSCs) is an essential event in the initiation and progression of liver fibrosis. MicroRNAs have been shown to play a pivotal role in regulating HSC functions such as cell proliferation, differentiation, and apoptosis. Recently, miR-181b has been reported to promote HSCs proliferation by targeting p27. But whether alpha-smooth muscle actin (α-SMA) or collagens could be promoted by miR-181b in activated HSCs is still not clear. Therefore, the understanding of the role of miR-181b in liver fibrosis remains limited. Our results showed that miR-181b expression was increased much higher than miR-181a expression in vitro in transforming growth factor-β1-induced HSC activation as well as in vivo in carbon tetrachloride-induced rat liver fibrosis. Of note, overexpression of miR-181b significantly increased the expressions level of α-SMA and type I collagen, and further promoted HSCs proliferation. Furthermore, phosphatase and tensin homologs deleted on chromosome 10 (PTEN), a negative regulator of PI3K/Akt pathway, were confirmed as a direct target of miR-181b. We demonstrated that miR-181b could suppress PTEN expression and increase Akt phosphorylation in HSCs. Interestingly, the effects of miR-181b on the activation of HSCs were blocked down by Akt inhibitor LY294002. Our results revealed a profibrotic role of miR-181b in HSC activation and demonstrated that miR-181b could activate HSCs, at least in part, via PTEN/Akt pathway.

  5. Hydrogen sulfide prevents Abeta-induced neuronal apoptosis by attenuating mitochondrial translocation of PTEN.

    Science.gov (United States)

    Cui, Weigang; Zhang, Yinghua; Yang, Chenxi; Sun, Yiyuan; Zhang, Min; Wang, Songtao

    2016-06-14

    Neuronal cell apoptosis is an important pathological change in Alzheimer's disease (AD). Hydrogen sulfide (H(2)S) is known to be a novel gaseous signaling molecule and a cytoprotectant in many diseases including AD. However, the molecular mechanism of the antiapoptosis activity of H(2)S in AD is not yet fully understood. The aim of the present study is to evaluate the inhibitory effects of H(2)S on Abeta (Aβ)-induced apoptosis and the molecular mechanisms underlying primary neuron cells. Our results showed that sodium hydrosulfide (NaHS), a donor of H(2)S, significantly ameliorated Aβ-induced cell apoptosis. NaHS also reversed the Aβ-induced translocation of the phosphatase and tensin homologs deleted on chromosome 10 (PTEN) from the cytosol to the mitochondria. Furthermore, H(2)S increased the level of p-AKT/AKT significantly. Interestingly, the antiapoptosis effects of H(2)S were blocked down by specific PI3K/AKT inhibitor wortmannin. In conclusion, these data indicate that H(2)S inhibits Aβ-induced neuronal apoptosis by attenuating mitochondrial translocation of PTEN and that activation of PI3K/AKT signaling pathway plays a critical role in H(2)S-mediated neuronal protection. Our findings provide a novel route into the molecular mechanisms of neuronal apoptosis in AD.

  6. Hereditary breast cancer associated with Cowden syndrome-related PTEN mutation with Lhermitte-Duclos disease.

    Science.gov (United States)

    Kimura, Fuyo; Ueda, Ai; Sato, Eiichi; Akimoto, Jiro; Kaise, Hiroshi; Yamada, Kimito; Hosonaga, Mari; Kawai, Yuko; Teraoka, Saeko; Okazaki, Miki; Ishikawa, Takashi

    2017-12-01

    Cowden syndrome is characterized by multiple hamartomas in various tissues, including the skin, brain, breast, thyroid, mucous membrane, and gastrointestinal tract, and is reported to increase the risk of malignant disease. We describe the case of a 52-year-old woman in whom a tumor was diagnosed in the left cerebellar hemisphere and treated by surgical resection. Phosphatase and tensin homolog (PTEN) mutation in exon 8 insertion was found in the brain tumor tissue and leukocytes. This finding supported the diagnosis of Cowden syndrome. She consequently developed endometrial cancer and underwent abdominal total hysterectomy with bilateral salpingo-oophorectomy. Four years later, hormone receptor-positive breast cancer was found in the right breast, and breast-conserving surgery with radiation therapy and sentinel lymph node biopsy was performed. Herein, we describe a patient who was diagnosed as having familial breast cancer associated with PTEN mutation-related Cowden syndrome. We also reviewed reports of this syndrome in the literature for disease appraisal.

  7. Clinical Implications for Germline PTEN Spectrum Disorders.

    Science.gov (United States)

    Ngeow, Joanne; Sesock, Kaitlin; Eng, Charis

    2017-06-01

    Patients with PTEN hamartoma tumor syndrome (PHTS) may present to a variety of different subspecialties with benign and malignant clinical features. They have increased lifetime risks of breast, endometrial, thyroid, renal, and colon cancers, as well as neurodevelopmental disorders such as autism spectrum disorder. Patients and affected family members can be offered gene-directed surveillance and management. Patients who are unaffected can be spared unnecessary investigations. With longitudinal follow-up, we are likely to identify other non-cancer manifestations associated with PHTS such as metabolic, immunologic, and neurologic features. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Transposon mutagenesis identifies genes that cooperate with mutant Pten in breast cancer progression

    Science.gov (United States)

    Rangel, Roberto; Lee, Song-Choon; Hon-Kim Ban, Kenneth; Guzman-Rojas, Liliana; Mann, Michael B.; Newberg, Justin Y.; McNoe, Leslie A.; Selvanesan, Luxmanan; Ward, Jerrold M.; Rust, Alistair G.; Chin, Kuan-Yew; Black, Michael A.; Jenkins, Nancy A.; Copeland, Neal G.

    2016-01-01

    Triple-negative breast cancer (TNBC) has the worst prognosis of any breast cancer subtype. To better understand the genetic forces driving TNBC, we performed a transposon mutagenesis screen in a phosphatase and tensin homolog (Pten) mutant mice and identified 12 candidate trunk drivers and a much larger number of progression genes. Validation studies identified eight TNBC tumor suppressor genes, including the GATA-like transcriptional repressor TRPS1. Down-regulation of TRPS1 in TNBC cells promoted epithelial-to-mesenchymal transition (EMT) by deregulating multiple EMT pathway genes, in addition to increasing the expression of SERPINE1 and SERPINB2 and the subsequent migration, invasion, and metastasis of tumor cells. Transposon mutagenesis has thus provided a better understanding of the genetic forces driving TNBC and discovered genes with potential clinical importance in TNBC. PMID:27849608

  9. Short-Term PTEN Inhibition Improves In Vitro Activation of Primordial Follicles, Preserves Follicular Viability, and Restores AMH Levels in Cryopreserved Ovarian Tissue From Cancer Patients.

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    Edurne Novella-Maestre

    Full Text Available In vitro activation and growth of primordial dormant follicles to produce fertilizable oocytes would provide a useful instrument for fertility preservation. The employment of Phosphatase and TENsin homolog (PTEN inhibitors, in combination with Protein kinase B (Akt stimulating molecules, has been previously employed to increase follicular activation through the stimulation of the PTEN-Akt pathway.We aim to establish improved in vitro activation also for cancer patients whose ovarian tissue has already been cryopreserved. Fresh and previously cryopreserved human ovarian cortex were exposed to short-term, low-concentration and ovary-specific treatment with only a PTEN inhibitor.Our in vitro activation protocol enhances the activation mechanisms of primordial follicles in both fresh and cryopreserved samples, and enlarges growing populations without inducing apoptosis in either follicles or the surrounding stroma. Treatment augments estradiol secretion and restores the expression levels of the previously diminished Anti-Müllerian hormone by means of cryopreservation procedures. Genomic modulation of the relative expression of PTEN pathway genes was found in treated samples.The in vitro activation protocol offers new alternatives for patients with cryopreserved tissue as it increases the pool of viable activated follicles available for in vitro growth procedures. The combination of ovarian tissue cryopreservation and in vitro activation of primordial follicles, the main ovarian reserve component, will be a major advancement in fertility preservation.

  10. Alkylation of the tumor suppressor PTEN activates Akt and β-catenin signaling: a mechanism linking inflammation and oxidative stress with cancer.

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    Tracy M Covey

    Full Text Available PTEN, a phosphoinositide-3-phosphatase, serves dual roles as a tumor suppressor and regulator of cellular anabolic/catabolic metabolism. Adaptation of a redox-sensitive cysteinyl thiol in PTEN for signal transduction by hydrogen peroxide may have superimposed a vulnerability to other mediators of oxidative stress and inflammation, especially reactive carbonyl species, which are commonly occurring by-products of arachidonic acid peroxidation. Using MCF7 and HEK-293 cells, we report that several reactive aldehydes and ketones, e.g. electrophilic α,β-enals (acrolein, 4-hydroxy-2-nonenal and α,β-enones (prostaglandin A(2, Δ12-prostaglandin J(2 and 15-deoxy-Δ-12,14-prostaglandin J(2 covalently modify and inactivate cellular PTEN, with ensuing activation of PKB/Akt kinase; phosphorylation of Akt substrates; increased cell proliferation; and increased nuclear β-catenin signaling. Alkylation of PTEN by α,β-enals/enones and interference with its restraint of cellular PKB/Akt signaling may accentuate hyperplastic and neoplastic disorders associated with chronic inflammation, oxidative stress, or aging.

  11. Phosphoinositide 5- and 3-phosphatase activities of a voltage-sensing phosphatase in living cells show identical voltage dependence.

    Science.gov (United States)

    Keum, Dongil; Kruse, Martin; Kim, Dong-Il; Hille, Bertil; Suh, Byung-Chang

    2016-06-28

    Voltage-sensing phosphatases (VSPs) are homologs of phosphatase and tensin homolog (PTEN), a phosphatidylinositol 3,4-bisphosphate [PI(3,4)P2] and phosphatidylinositol 3,4,5-trisphosphate [PI(3,4,5)P3] 3-phosphatase. However, VSPs have a wider range of substrates, cleaving 3-phosphate from PI(3,4)P2 and probably PI(3,4,5)P3 as well as 5-phosphate from phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] and PI(3,4,5)P3 in response to membrane depolarization. Recent proposals say these reactions have differing voltage dependence. Using Förster resonance energy transfer probes specific for different PIs in living cells with zebrafish VSP, we quantitate both voltage-dependent 5- and 3-phosphatase subreactions against endogenous substrates. These activities become apparent with different voltage thresholds, voltage sensitivities, and catalytic rates. As an analytical tool, we refine a kinetic model that includes the endogenous pools of phosphoinositides, endogenous phosphatase and kinase reactions connecting them, and four exogenous voltage-dependent 5- and 3-phosphatase subreactions of VSP. We show that apparent voltage threshold differences for seeing effects of the 5- and 3-phosphatase activities in cells are not due to different intrinsic voltage dependence of these reactions. Rather, the reactions have a common voltage dependence, and apparent differences arise only because each VSP subreaction has a different absolute catalytic rate that begins to surpass the respective endogenous enzyme activities at different voltages. For zebrafish VSP, our modeling revealed that 3-phosphatase activity against PI(3,4,5)P3 is 55-fold slower than 5-phosphatase activity against PI(4,5)P2; thus, PI(4,5)P2 generated more slowly from dephosphorylating PI(3,4,5)P3 might never accumulate. When 5-phosphatase activity was counteracted by coexpression of a phosphatidylinositol 4-phosphate 5-kinase, there was accumulation of PI(4,5)P2 in parallel to PI(3,4,5)P3 dephosphorylation

  12. Phosphatase and Tension Homolog Overexpression in Insulin Resistant Diabetic Adipose Tissue

    Institute of Scientific and Technical Information of China (English)

    Jing-bo Zeng; Yun Zhang; Qi Sun; and Yu-xiu Li

    2014-01-01

    Objective To investigate the expression of phosphatase and tension homolog (PTEN) in adipose tissue of KKAy diabetic mice, a mouse model of type 2 diabetes. Methods KKAy diabetic mice were fed with high fat diet for 4 weeks. After blood glucose met the criteria of diabetes (over 16.7 mmol/L), mice were randomly divided into 3 groups:a control group (without any treatment), a rosiglitazone group (treated with rosiglitazone 12.5 mg/kg·d once per day), and a metformin group (treated with metformin 3 g/kg·d twice daily). After 4 weeks, we then determined the expression of PTEN and phosphoserine 473-Akt (pS473-Akt) in the epididymal adipose tissue with Western blots. The mice in each group were further divided into the insulin (-) subgroup and insulin (+) subgroup, which were intraperitoneally injected with saline and insulin (5 mU/g body weight), respectively. Results The expression of PTEN was elevated in the epididymal adipose tissue obtained from KKAy diabetic mice compared with that from the C57BL/6J mice (P Conclusion PTEN may play an important role in the development of insulin resistance in adipose tissue of type 2 diabetes mice model.

  13. WWP2 and its association with PTEN in endometrial cancer

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    Aine E. Clements

    2015-08-01

    We found that in tumors with low PTEN protein but normal mRNA expression there were significantly higher levels of WWP2 expression (p = 0.0017. Increased WWP2 expression was not associated with clinical prognostic factors including lymphovascular space invasion, ≥50% myometrial invasion, grade, stage or recurrence. WWP2 expression was not different statistically between tumors and normal controls (p = NS. Therefore, in this cohort, tumors with low PTEN protein but normal mRNA expression had elevated levels of WWP2 expression. This suggests that WWP2 may be playing a role in PTEN degradation in endometrial cancer.

  14. CDX2 Inhibits Invasion and Migration of Gastric Cancer Cells by Phosphatase and Tensin Homologue Deleted from Chromosome 10/Akt Signaling Pathway

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    Yong-Qiang Liu

    2015-01-01

    Full Text Available Background: Gastric cancer (GC is one of the most prevalent malignancies in the world today, with a high mortality rate. CDX2 is a Drosophila caudal-related homeobox transcription factor that plays an important role in GC. Phosphatase and tensin homologue deleted from chromosome 10 (PTEN is an important tumor suppressor which is widely expressed in normal human tissues. The aim of the study was to determine the relationship and mechanism between CDX2 and PTEN in invasion and migration of GC cells. Methods: pcDNA3-CDX2 plasmids were transfected into MGC-803 cells to up-regulate CDX2 protein, and small interfering RNA-CDX2 was transfected to down-regulate CDX2. The influence of CDX2 or PTEN on cell migration and invasion was measured by invasion, migration and wound healing assays. Western blotting assay and immunofluorescence were used to detect the expression of CDX2, PTEN, phosphorylation of Akt, E-cadherin and N-cadherin. Statistical significance was determined by one-way analysis of variance. Results: The results showed that CDX2 reduced the migration and invasion of GC cells (P < 0.05, and inhibited the activity of Akt through down-regulating PTEN expression (P < 0.05. CDX2 also restrained epithelial-mesenchymal transition of GC cells. Conclusions: CDX2 inhibited invasion and migration of GC cells by PTEN/Akt signaling pathway, and that may be used for potential therapeutic target.

  15. Expression and clinical significance of MN1 and PTEN gene in patients with acute myeloid leukemia%MH1和PTEN基因在急性髓系白血病中的表达及临床意义

    Institute of Scientific and Technical Information of China (English)

    Xueshen Yan; Fanjun Meng; Hongguo Zhao; Jie Yang

    2011-01-01

    Objective: The aim of our study was to explore the correlations between both the genes, evolution and prognosis of the disease by detecting the expression of MN1 (meningioma 1) gene and PTEN (phosphatase and tensin homolog) gene in patients with acute myeloid leukemia (AML). Method: MN1 and PTEN mRNA were detected by reverse transcription-PCR in mononuclear cells of 38 patients with AML and 13 patients with normal bone marrow. Results: Positive rates of MN1 and PTEN genes were 76.3% and 60.5% respectively in bone marrow mononuclear cells. The expression level of MN1 mRNA for the de novo group increased comparing with that for normal control group (P < 0.05), the expression level of PTEN mRNA for de novo group decreased obviously comparing with that for normal control group (P < 0.01), MN1 mRNA level decreased in remission group, while PTEN mRNA level increased comparing with that in de novo group (P < 0.05). MN1 mRNA level increased and PTEN mRNA decreased in relapsed group comparing with that in control group, and their difference was statistical significance (P < 0.05). The two genes' levels had negative correlations in acute myeloid leukemia (r = –0.314, P < 0.05). Conclusion: There is close correlations between expression of MN1 and PTEN genes and the prognosis and occurrence of acute myeloid leukemia, and their expression can be taken as significant indexes to access the de novo, relapse and prognosis of acute myeloid leukemia.

  16. DNA methylation of PTEN gene promoter region is not correlated ...

    African Journals Online (AJOL)

    Yomi

    2012-02-23

    Feb 23, 2012 ... Key words: PTEN, promoter methylation, bladder cancer. INTRODUCTION ... al., 2005), pancreatic cancer (Asano et al., 2004), thyroid cancer (Frisk et al., ..... papillary mucinous neoplasms of the pancreas. J. Hepatobiliary.

  17. Expression of Phosphatase and Tensin Homologue, phospho-Akt, and p53 in Acral Benign and Malignant Melanocytic Neoplasms (Benign Nevi, Dysplastic Nevi, and Acral Melanomas)

    Science.gov (United States)

    Lyu, So Min; Wu, Ju Yeon; Byun, Ji Yeon; Choi, Hae Young; Park, Sang Hee

    2016-01-01

    Background The role of the phosphatidylinositol-3 kinase signaling pathway in the development of acral melanoma has recently gained evidence. Phosphatase and tensin homologue (PTEN), one of the key molecules in the pathway, acts as a tumor suppressor through either an Akt-dependent or Akt-independent pathway. Akt accelerates degradation of p53. Objective We assessed the expression of PTEN, phospho-Akt (p-Akt), and p53 by immunohistochemistry in benign acral nevi, acral dysplastic nevi, and acral melanomas in the radial growth phase and with a vertical growth component. Methods Ten specimens in each group were included. Paraffin-embedded specimens were immunostained with antibodies for PTEN, p-Akt, and p53. We scored both the staining intensity and the proportion of positive cells. The final score was calculated by multiplying the intensity score by the proportion score. Results All specimens of benign acral nevi except one showed some degree of PTEN-negative cells. The numbers of p-Akt and p53-positive cells were higher in acral dysplastic nevi and melanoma than in benign nevi. P-Akt scores were 1.7, 1.8, 2.6, and 4.4, and p53 scores were 2.0, 2.1, 3.8, and 4.1 in each group. PTEN and p-Akt scores in advanced acral melanoma were higher than in the other neoplasms. Conclusion The expression of PTEN was decreased and the expression of p-Akt was increased in acral melanoma, especially in advanced cases. The PTEN-induced pathway appears to affect the late stage of melanomagenesis. Altered expression of p-Akt is thought to be due to secondary changes following the loss of PTEN. PMID:27746632

  18. Subtle variations in Pten dose determine cancer susceptibility

    Science.gov (United States)

    Alimonti, Andrea; Carracedo, Arkaitz; Clohessy, John G; Trotman, Lloyd C; Nardella, Caterina; Egia, Ainara; Salmena, Leonardo; Sampieri, Katia; Haveman, William J; Brogi, Edi; Richardson, Andrea L; Zhang, Jiangwen; Pandolfi, Pier Paolo

    2010-01-01

    Cancer susceptibility has been attributed to at least one heterozygous genetic alteration in a tumor suppressor gene (TSG)1. It has been hypothesized that subtle variations in TSG expression can promote cancer development2,3. However, this hypothesis has not yet been definitively supported in vivo. PTEN is a TSG frequently lost in human cancer and mutated in inherited cancer-predisposition syndromes4. Here, we analyze Pten hypermorphic mice (Ptenhy/+), expressing 80% normal levels of Pten. Ptenhy/+ mice develop a spectrum of tumors, with breast tumors occurring at the highest penetrance. All breast tumors analyzed here retained two intact copies of Pten and maintained Pten levels above heterozygosis. Notably, subtle downregulation of Pten altered the steady-state biology of the mammary tissues and the expression profiles of genes involved in cancer cell proliferation. We present an alterative working model for cancer development in which subtle reductions in the dose of TSGs predispose to tumorigenesis in a tissue-specific manner. PMID:20400965

  19. Methods to Study PTEN in Mitochondria and Endoplasmic Reticulum.

    Science.gov (United States)

    Missiroli, Sonia; Morganti, Claudia; Giorgi, Carlotta; Pinton, Paolo

    2016-01-01

    Although PTEN has been widely described as a nuclear and cytosolic protein, in the last 2 years, alternative organelles, such as the endoplasmic reticulum (ER), pure mitochondria, and mitochondria-associated membranes (MAMs), have been recognized as pivotal targets of PTEN activity.Here, we describe different methods that have been used to highlight PTEN subcellular localization.First, a protocol to extract nuclear and cytosolic fractions has been described to assess the "canonical" PTEN localization. Moreover, we describe a protocol for mitochondria isolation with proteinase K (PK) to further discriminate whether PTEN associates with the outer mitochondrial membrane (OMM) or resides within the mitochondria. Finally, we focus our attention on a subcellular fractionation protocol of cells that permits the isolation of MAMs containing unique regions of ER membranes attached to the outer mitochondrial membrane (OMM) and mitochondria without contamination from other organelles. In addition to biochemical fractionations, immunostaining can be used to determine the subcellular localization of proteins; thus, a detailed protocol to obtain good immunofluorescence (IF) is described. The employment of these methodological approaches could facilitate the identification of different PTEN localizations in several physiopathological contexts.

  20. KRAS and BRAF Mutations and PTEN Expression Do Not Predict Efficacy of Cetuximab-Based Chemoradiotherapy in Locally Advanced Rectal Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Erben, Philipp, E-mail: philipp.erben@medma.uni-heidelberg.de [III. Medizinische Klinik, Universitaetsmedizin Mannheim, Universitaet Heidelberg, Mannheim (Germany); Stroebel, Philipp [Pathologisches Institut, Universitaetsmedizin Mannheim, Universitaet Heidelberg, Mannheim (Germany); Horisberger, Karoline [Chirurgische Klinik, Universitaetsmedizin Mannheim, Universitaet Heidelberg, Mannheim (Germany); Popa, Juliana; Bohn, Beatrice; Hanfstein, Benjamin [III. Medizinische Klinik, Universitaetsmedizin Mannheim, Universitaet Heidelberg, Mannheim (Germany); Kaehler, Georg; Kienle, Peter; Post, Stefan [Chirurgische Klinik, Universitaetsmedizin Mannheim, Universitaet Heidelberg, Mannheim (Germany); Wenz, Frederik [Klinik fuer Strahlentherapie und Radioonkologie, Universitaetsmedizin Mannheim, Universitaet Heidelberg, Mannheim (Germany); Hochhaus, Andreas [III. Medizinische Klinik, Universitaetsmedizin Mannheim, Universitaet Heidelberg, Mannheim (Germany); Klinik fuer Innere Medizin II, Abteilung Haematologie/Onkologie, Universitaetsklinikum Jena, Jena (Germany); Hofheinz, Ralf-Dieter [III. Medizinische Klinik, Universitaetsmedizin Mannheim, Universitaet Heidelberg, Mannheim (Germany)

    2011-11-15

    Purpose: Mutations in KRAS and BRAF genes as well as the loss of expression of phosphatase and tensin homolog (PTEN) (deleted on chromosome 10) are associated with impaired activity of antibodies directed against epidermal growth factor receptor in patients with metastatic colorectal cancer. The predictive and prognostic value of the KRAS and BRAF point mutations as well as PTEN expression in patients with locally advanced rectal cancer (LARC) treated with cetuximab-based neoadjuvant chemoradiotherapy is unknown. Methods and Materials: We have conducted phase I and II trials of the combination of weekly administration of cetuximab and irinotecan and daily doses of capecitabine in conjunction with radiotherapy (45 Gy plus 5.4 Gy) in patients with LARC (stage uT3/4 or uN+). The status of KRAS and BRAF mutations was determined with direct sequencing, and PTEN expression status was determined with immunohistochemistry testing of diagnostic tumor biopsies. Tumor regression was evaluated by using standardized regression grading, and disease-free survival (DFS) was calculated according to the Kaplan-Meier method. Results: A total of 57 patients were available for analyses. A total of 31.6% of patients carried mutations in the KRAS genes. No BRAF mutations were found, while the loss of PTEN expression was observed in 9.6% of patients. Six patients achieved complete remission, and the 3-year DFS rate was 73%. No correlation was seen between tumor regression or DFS rate and a single marker or a combination of all markers. Conclusions: In the present series, no BRAF mutation was detected. The presence of KRAS mutations and loss of PTEN expression were not associated with impaired response to cetuximab-based chemoradiotherapy and 3-year DFS.

  1. GRP78 as a regulator of liver steatosis and cancer progression mediated by loss of the tumor suppressor PTEN.

    Science.gov (United States)

    Chen, W-T; Zhu, G; Pfaffenbach, K; Kanel, G; Stiles, B; Lee, A S

    2014-10-16

    Glucose-regulated protein 78 (GRP78), a molecular chaperone widely elevated in human cancers, is critical for endoplasmic reticulum (ER) protein folding, stress signaling and PI3K/AKT activation. Genetic knockout models of GRP78 revealed that GRP78 maintains homeostasis of metabolic organs, including liver, pancreas and adipose tissues. Hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC) are the most common liver cancers. There is a lack of effective therapeutics for HCC and CC, highlighting the need to further understand liver tumorigenic mechanisms. PTEN (phosphatase and tenson homolog deleted on chromosome 10), a tumor suppressor that antagonizes the PI3K/AKT pathway, is inactivated in a wide range of tumors, including 40-50% of human liver cancers. To elucidate the role of GRP78 in liver cancer, we created a mouse model with biallelic liver-specific deletion of Pten and Grp78 mediated by Albumin-Cre-recombinase (cP(f/f)78(f/f)). Interestingly, in contrast to PTEN, deletion of GRP78 was progressive but incomplete. At 3 months, cP(f/f)78(f/f) livers showed hepatomegaly, activation of lipogenic genes, exacerbated steatosis and liver injury, implying that GRP78 protects the liver against PTEN-null-mediated pathogenesis. Furthermore, in response to liver injury, we observed increased proliferation and expansion of bile duct and liver progenitor cells in cP(f/f)78(f/f) livers. Strikingly, bile duct cells in cP(f/f)78(f/f) livers maintained wild-type (WT) GRP78 level, whereas adjacent areas showed GRP78 reduction. Analysis of signaling pathways revealed selective JNK activation, β-catenin downregulation, along with PDGFRα upregulation, which was unique to cP(f/f)78(f/f) livers at 6 months. Development of both HCC and CC was accelerated and was evident in cP(f/f)78(f/f) livers at 8-9 months, coinciding with intense GRP78 expression in the cancer lesions, and GRP78 expression in adjacent normal areas reverted back to the WT level. In contrast, c78(f/f) livers

  2. Genetic aberration of PTEN in peripheral T cell lymphoma, not otherwise specified%非特指外周T细胞淋巴瘤中PTEN的改变

    Institute of Scientific and Technical Information of China (English)

    朱文娟; 张建中

    2012-01-01

    目的 观察非特指外周T细胞淋巴瘤(peripheral T cell lymphoma,not otherwise specified,PTCL-NOS)中抑癌基因(phosphatase and tensin homolog deleted on chromosome ten,PTEN)的改变情况,探讨其与肿瘤生物学行为的关系,为阐明PTCL-NOS的发生、发展机制提供科学依据.方法应用间期双色荧光原位杂交(fluorescence in situ hybridization,FISH)技术检测36例PTCL-NOS石蜡包埋组织中PTEN基因的改变情况,分析其改变与各临床参数的关系.结果 36例PTCL-NOS中8例出现PTEN杂合性缺失(loss of heterozygosity,LOH);Kaplan-Meier生存分析显示该基因异常组较正常组生存期明显缩短(P0.05).结论 PTCL-NOS存在的抑癌基因PTEN杂合性缺失,在PTCL-NOS发生、发展中可能起重要作用,是评估该肿瘤预后的重要指标.%Purpose To investigate the genetic changes of tumor suppressor gene PTEN in PTCL-NOS, and to explore its relationship with the development of PTCL-NOS and other clinicopathological parameters. Methods Thirty-six cases of PTCL-NOS were studied by fluorescence in-situ hybridization ( FISH ) using interphase dual-colour probes. The probes were generated from BAC clones RP11 - 380G5 corresponding to PTEN gene. Correlation of the genetic changes with patients prognosis and other clinical parameters was analyzed. Results Loss of heterozygosity ( LOH ) of PTEN presented in 8/36 cases; Kaplan-Meier survival analysis indicated there was a trend that the group with PTEN gene change had a poorer prognosis than the group without PTEN gene change ( P 0. 05 ). Conclusion A significant percentage of PTCL-NOS carry the genetic alteration of PTEN that may play an important role in the pathogenesis of PTCL-NOS and the e-valuation of the patient' s prognosis.

  3. Cdc14 phosphatase

    DEFF Research Database (Denmark)

    Machín, Félix; Quevedo Rodriguez, Oliver; Ramos-Pérez, Cristina

    2016-01-01

    Cycling events in nature start and end to restart again and again. In the cell cycle, whose purpose is to become two where there was only one, cyclin-dependent kinases (CDKs) are the beginning and, therefore, phosphatases must play a role in the ending. Since CDKs are drivers of the cell cycle an...

  4. PTEN: a default gate-keeping tumor suppressor with a versatile tail

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The tumor suppressor PTEN controls a variety of biological processes including cell proliferation, growth, migration, and death. As a master cellular regulator, PTEN itself is also subjected to deliberated regulation to ensure its proper function. Defects in PTEN regulation have a profound impact on carcinogenesis. In this review, we briefly discuss recent advances concerning PTEN regulation and how such knowledge facilitates our understanding and further exploration of PTEN biology. The carboxyl-tail of PTEN, which appears to be associated with multiple types of posttranslational regulation, will be under detailed scrutiny. Further, a comparative analysis of PTEN and p53 suggests while p53 needs to be activated to suppress tumorigenesis (a dormant gatekeeper), PTEN is probably a constitutive surveillant against cancer development, thus a default gatekeeper.

  5. Phosphatase-triggered fusogenic liposomes for cytoplasmic delivery of cell-impermeable compounds.

    Science.gov (United States)

    Motion, J P Michael; Nguyen, Juliane; Szoka, Francis C

    2012-09-03

    License to fuse! A phosphorylated fusion peptide can mediate membrane fusion when the phosphates (green triangles, see scheme) are removed by phosphatases (blue spheres), delivering the contents of the liposome into the cytosol. This phosphatase-triggered approach may be useful to create target-specific lipid nanocarriers. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Reduced Expression of PTEN Protein and Its Prognostic Significance in the Gastrointestinal Stromal Tumor

    Institute of Scientific and Technical Information of China (English)

    张永红; 于冬冬; 李小兰; 胡俊波; 龚建平

    2010-01-01

    Little is reported about the role of PTEN gene in the progression and prognosis of GISTs.This study examined the clinical implications of the tumor suppressor gene PTEN as a prognostic factor in the GISTs.Immunohistological staining and immunoblotting were employed to examine the PTEN protein expression,and its association with clinical measures.Clinicopathological features were reviewed by a retrospective examination of medical records.Reduced PTEN expression was significantly associated with tumor diamete...

  7. MiR-26a inhibits proliferation and migration of HaCaT keratinocytes through regulating PTEN expression.

    Science.gov (United States)

    Yu, Nanze; Yang, Yang; Li, Xiongwei; Zhang, Mingzi; Huang, Jiuzuo; Wang, Xiaojun; Long, Xiao

    2016-12-05

    MicroRNAs (miRNAs) have been shown to be associated with differentiation, migration and apoptosis in keratinocyte. Although it has been reported that microRNA-26a (miR-26a) plays important roles in tumor cells, its biological functions in keratinocytes are still not well elucidated. In this study, we confirmed expression of miR-26a in human keratinocytes using RT-PCR and further studied the role of miR-26a in cell proliferation and cell migration. Ectopic expression of MiR-26a mimic or inhibitor increased or decreased miR-26a expression respectively in HaCaT cells. Proliferation of HaCaT keratinocyte can be suppressed or promoted by overexpression or down-expression of miR-26a. In scratch wound-healing assay and Boyden chamber cell migration assay, upregulating miR-26a expression blocked cell migration, while downregulating miR-26a expression enhanced the migration. Using quantitative RT-PCR (qRT-PCR) and western blot, we further discovered that both mRNA and protein level of phosphatase and tensin homolog deleted from chromosome 10(PTEN) were regulated by miR-26a in HaCaT cells. Meanwhile the level of active form of AKT was also regulated by the miR-26a. In rescue experiment, knockdown of PTEN in the miR-26a mimic transduced cells recovered the migration ability of HaCaT cells. Together these results suggest that miR-26a modulates the proliferation and migration of keratinocytes via regulating PTEN/AKT signaling pathway.

  8. Glucose-6-phosphatase deficiency.

    OpenAIRE

    Labrune Philippe; Gajdos Vincent; Eberschweiler Pascale; Hubert-Buron Aurélie; Petit François; Vianey-Saban Christine; Boudjemline Alix; Piraud Monique; Froissart Roseline

    2011-01-01

    Abstract Glucose-6-phosphatase deficiency (G6P deficiency), or glycogen storage disease type I (GSDI), is a group of inherited metabolic diseases, including types Ia and Ib, characterized by poor tolerance to fasting, growth retardation and hepatomegaly resulting from accumulation of glycogen and fat in the liver. Prevalence is unknown and annual incidence is around 1/100,000 births. GSDIa is the more frequent type, representing about 80% of GSDI patients. The disease commonly manifests, betw...

  9. Up-regulation of miR-26a promotes neurite outgrowth and ameliorates apoptosis by inhibiting PTEN in bupivacaine injured mouse dorsal root ganglia.

    Science.gov (United States)

    Cui, Changlei; Xu, Gong; Qiu, Jinpeng; Fan, Xiushuang

    2015-08-01

    Local anesthetic of bupivacaine may inhibit neurite outgrowth and induce apoptosis in mouse dorsal root ganglia (DRG) neurons. In this work, we intended to investigate the functional role of microRNA 26a (miR-26a) in regulating bupivacaine-induced nerve injury in DRG neurons. DRG neurons were extracted from C57BL/6 mice and cultured in vitro. Bupivacaine was applied in vitro and it induced apoptosis, inhibited neurite growth, and significantly down-regulated miR-26a gene in DRG neurons. MiR-26a mimic was then used to up-regulate miR-26a expression in DRG neurons. We found that miR-26a up-regulation promoted neurite outgrowth and reduced apoptosis in bupivacaine-injured DRG neurons. Luciferase assay and Western blot confirmed that Phosphatase and tensin homolog (PTEN) was down-stream target of miR-26a in DRG neurons. Ectopic PTEN up-regulation was then able to reverse the protective effect of miR-26a overexpression on bupivacaine-induced nerve injury in DRG neurons. Overall, this work demonstrated that miR-26a had a functional role in regulating bupivacaine-induced nerve injury in DRG neurons. Up-regulating miR-26a to suppress PTEN signaling pathway may be an effective method to protect local anesthetic-induced nerve injury in spinal cord.

  10. MiR-21 inhibitor suppressed the progression of retinoblastoma via the modulation of PTEN/PI3K/AKT pathway.

    Science.gov (United States)

    Gui, Fu; Hong, Zhengdong; You, Zhipeng; Wu, Hongxi; Zhang, Yulan

    2016-12-01

    MicroRNA-21 (miR-21) was reported to act as an oncogene during the development of many human tumors. However, little was revealed about the function of miR-21 in retinoblastoma (RB). In this study, we examined the expression of miR-21 in RB tissues and explored the relationship between miR-21 and phosphatase and tensin homolog (PTEN)/phosphatidylinositol-3-OH kinase (PI3K)/AKT signal. Quantitative real-time PCR (qRT-PCR) results showed that the level of miR-21 in RB tissues was higher than that in retinal normal tissues. In Weri-Rb-1 cells, miR-21 inhibitor suppressed the expression of miR-21 and cell viability, but improved cell apoptotic rates by modulating the levels of PDCD4, Bax, and Bcl-2. Meanwhile, miR-21 inhibitor suppressed cell migration and invasion via inhibiting the protein levels of MMP2 and MMP9 and significantly affected the expression of PTEN, PI3K, and p-AKT. Taken together, miR-21 inhibitor suppressed cell proliferation, migration, and invasion via the PTEN/PI3K/AKT signal. These findings revealed the molecular basis of miR-21 functioning in the progression of RB and provided a new means for cell therapy in RB.

  11. Mitochondria-related miR-141-3p contributes to mitochondrial dysfunction in HFD-induced obesity by inhibiting PTEN.

    Science.gov (United States)

    Ji, Juan; Qin, Yufeng; Ren, Jing; Lu, Chuncheng; Wang, Rong; Dai, Xiuliang; Zhou, Ran; Huang, Zhenyao; Xu, Miaofei; Chen, Minjian; Wu, Wei; Song, Ling; Shen, Hongbing; Hu, Zhibin; Miao, Dengshun; Xia, Yankai; Wang, Xinru

    2015-11-09

    Mitochondria-related microRNAs (miRNAs) have recently emerged as key regulators of cell metabolism and can modulate mitochondrial fusion and division. In order to investigate the roles of mitochondria-related miRNAs played in obesity, we conducted comprehensive molecular analysis in vitro and in vivo. Based on high-fat-diet (HFD) induced obese mice, we found that hepatic mitochondrial function was markedly altered. Subsequently, we evaluated the expression levels of selected mitochondria-related miRNAs and found that miR-141-3p was up-regulated strikingly in HFD mice. To further verify the role of miR-141-3p in obesity, we carried out gain-and-loss-of-function study in human HepG2 cells. We found that miR-141-3p could modulate ATP production and induce oxidative stress. Through luciferase report gene assay, we identified that phosphatase and tensin homolog (PTEN) was a target of miR-141-3p. Inhibiting PTEN could alter the mitochondrial function, too. Our study suggested that mitochondria-related miR-141-3p induced mitochondrial dysfunction by inhibiting PTEN.

  12. MicroRNA-616 promotes the migration, invasion and epithelial-mesenchymal transition of HCC by targeting PTEN.

    Science.gov (United States)

    Zhang, Di; Zhou, Peihua; Wang, Wei; Wang, Xiaolong; Li, Junhui; Sun, Xuejun; Zhang, Li

    2016-01-01

    MicroRNAs, which can post-transcriptionally regulate gene expression by binding to the 3'-untranslated regions of the mRNAs, have been found to be the critical regulators of the development and progression of hepatocellular carcinoma (HCC). The present study demonstrated for the first time that microRNA-616 (miR-616) was markedly upregulated in HCC tissues, and was associated with the recurrence and metastasis of HCC. Elevated level of miR-616 was correlated with adverse clinicopathological features and poor prognosis of HCC patients. Gain- and loss-of-function studies revealed that miR-616 could potentiate the migration, invasion and the epithelial-mesenchymal transtion (EMT) phenotype of HCC cells. Phosphatase and tensin homolog (PTEN), the predicted target of miR-616 by bioinformatics analysis, was confirmed as a direct downstream target of miR-616 through western blotting, luciferase reporter and immunohistochemical assays. Furthermore, we demonstrated that miR-616 exerted the promoting effects on EMT and metastatic ability of HCC cells through suppressing PTEN expression. Based on these results, we conclude that miR-616 is a promising prognostic biomarker of HCC and targeting miR-616 may be a potential option to prevent the progression of HCC.

  13. PTEN overexpression improves cisplatin-resistance of human ovarian cancer cells through upregulating KRT10 expression

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Huijuan; Wang, Ke; Liu, Wenxin; Hao, Quan, E-mail: quan_haotj@126.com

    2014-02-07

    Highlights: • Overexpression of PTEN enhanced the sensitivity of C13K cells to cisplatin. • KRT10 is a downstream molecule of PTEN involved in the resistance-reversing effect. • Overexpression of KRT10 enhanced the chemosensitivity of C13K cells to cisplatin. - Abstract: Multi-drug resistance (MDR) is a common cause of the failure of chemotherapy in ovarian cancer. PTEN, a tumor suppressor gene, has been demonstrated to be able to reverse cisplatin-resistance in ovarian cancer cell line C13K. However, the downstream molecules of PTEN involved in the resistance-reversing effect have not been completely clarified. Therefore, we screened the downstream molecules of PTEN and studied their interactions in C13K ovarian cancer cells using a 3D culture model. Firstly, we constructed an ovarian cancer cell line stably expressing PTEN, C13K/PTEN. MTT assay showed that overexpression of PTEN enhanced the sensitivity of C13K cells to cisplatin, but not to paclitaxel. Then we examined the differently expressed proteins that interacted with PTEN in C13K/PTEN cells with or without cisplatin treatment by co-immunoprecipitation. KRT10 was identified as a differently expressed protein in cisplatin-treated C13K/PTEN cells. Further study confirmed that cisplatin could induce upregulation of KRT10 mRNA and protein in C13K/PTEN cells and there was a directly interaction between KRT10 and PTEN. Forced expression of KRT10 in C13K cells also enhanced cisplatin-induced proliferation inhibition and apoptosis of C13K cells. In addition, KRT10 siRNA blocked cisplatin-induced proliferation inhibition of C13K/PTEN cells. In conclusion, our data demonstrate that KRT10 is a downstream molecule of PTEN which improves cisplatin-resistance of ovarian cancer and forced KRT10 overexpression may also act as a therapeutic method for overcoming MDR in ovarian cancer.

  14. Molecular Mechanism of Nkx3.1 Deregulation and its Function in Murine Pten Prostate Cancer Model

    Science.gov (United States)

    2006-09-01

    hybridization , post hybridization , and analyses following standard laboratory procedure. The probe cocktail contained 20 differentially labeled chromosome...contain near tetraploid chromosome number, with 65-84 chromosomes in PTEN-P2 and 76-80 chromosomes in PTEN-CaP2; PTEN- P8 and PTEN-CaP8 have near 6N

  15. PTEN在氯化锂-匹罗卡品癫痫模型中的表达研究%Expression of PTEN in the lithium -pilocarpine model of epilepsy

    Institute of Scientific and Technical Information of China (English)

    吕耀东; 王学峰

    2013-01-01

    目的:检测第10号染色体同源丢失性磷酸酶张力蛋白基因(phosphatase and tensin homolog deleted on chromosome ten ,PTEN)在癫痫模型大鼠中的表达情况,初步探讨其在癫痫发病中的作用。方法:成年雄性SD 大鼠腹腔注射氯化锂-匹罗卡品(lithium -pilocarpine )构建癫痫模型,分别在癫痫发作后不同时间点(1 d、3 d、7 d、14 d、30 d)提取海马组织,利用荧光定量PCR和western blot分别测定PTEN mRNA和蛋白质的表达。结果:荧光定量PCR和western blot显示,PTEN mRNA 和蛋白质在癫痫发作后1 d的表达显著降低(P<0.05),到30 d 时仍维持在较低的水平(P<0.05)。结论:PTEN在氯化锂-匹罗卡品致痫大鼠海马组织中表达的降低,提示PTEN可能参与了癫痫的发生发展过程。%Objective :To investigate the expression of phosphatase and tensin homolog deleted on chromosome ten (PTEN) in a rat model of epilepsy and its potential role in epilepsy .Methods Adult male SD rats were intraperitoneally injected with lithium -pilocarpine for the epilepsy model .And at different time points (1 d、3 d、7 d、14 d、30 d) after seizures ,the expression of PTEN at mRNA and protein was detected in the hippocampus using real -time PCR and western blot respectively .Results :The expression of PTEN at mRNA and protein was significantly decreased at 1 d (P<0 .05) ,and remained at a lower level by 30 d (P<0 .05) after pilocarpine -induced seizures .Conclusion The expression of PTEN was markedly decreased in the hippocampus in the rat lithium -pilocarpine model of epilepsy ,indicating that PTEN may be involved in epileptogenesis .

  16. Strain-Specific Spontaneous and NNK-Mediated Tumorigenesis in Pten+/− Mice

    Directory of Open Access Journals (Sweden)

    Mary Christine Hollander

    2008-08-01

    Full Text Available Pten is a negative regulator of the Akt pathway, and its inactivation is believed to be an etiological factor in many tumor types. Pten+/- mice are susceptible to a variety of spontaneous tumor types, depending on strain background. Pten+/- mice, in lung tumor-sensitive and -resistant background strains, were treated with a tobacco carcinogen, 4-(methylnitrosamino-1-(3-pyridyl-1-butanone (NNK, to determine whether allelic Pten deletion can cooperate with NNK in carcinogenesis in lung or other tissues. In lung tumor-resistant C57BL/6 Pten+/- or +/+ mice, NNK treatment did not lead to any lung tumors and did not increase the incidence or severity of tumors previously reported for this strain. In contrast, in a lung tumor-susceptible pseudo-A/J strain, there was a dose-dependent increase in lung tumor size in Pten+/- compared with +/+ mice, although there was no increase in multiplicity. No other tumor types were observed in pseudo-A/J Pten+/- mice regardless of NNK treatment. Lung tumors from these Pten+/- mice had K-ras mutations, retained Pten expression and had similar Akt pathway activation as lung tumors from +/+ mice. Therefore, deletion of a single copy of Pten does not substantially add to the lung tumor phenotype conferred by mutation of K-ras by NNK, and there is likely no selective advantage for loss of the second Pten allele in lung tumor initiation.

  17. The soybean peptide lunasin promotes apoptosis of mammary epithelial cells via induction of tumor suppressor PTEN: similarities and distinct actions from soy isoflavone genistein.

    Science.gov (United States)

    Pabona, John Mark P; Dave, Bhuvanesh; Su, Ying; Montales, Maria Theresa E; de Lumen, Ben O; de Mejia, Elvira G; Rahal, Omar M; Simmen, Rosalia C M

    2013-01-01

    Breast cancer is the leading cause of cancer deaths in women. Diet and lifestyle are major contributing factors to increased breast cancer risk. While mechanisms underlying dietary protection of mammary tumor formation are increasingly elucidated, there remains a dearth of knowledge on the nature and precise actions of specific bioactive components present in foods with purported health effects. The 43-amino acid peptide lunasin (LUN) is found in soybeans, is bioavailable similar to the isoflavone genistein (GEN), and thus may mediate the beneficial effects of soy food consumption. Here, we evaluated whether LUN displays common and distinct actions from those of GEN in non-malignant (mouse HC11) and malignant (human MCF-7) mammary epithelial cells. In MCF-7 cells, LUN up-regulated tumor suppressor phosphatase and tensin homolog deleted in chromosome ten (PTEN) promoter activity, increased PTEN transcript and protein levels and enhanced nuclear PTEN localization, similar to that shown for GEN in mammary epithelial cells. LUN-induced cellular apoptosis, akin to GEN, was mediated by PTEN, but unlike that for GEN, was p53-independent. LUN promoted E-cadherin and β-catenin non-nuclear localization similar to GEN, but unlike GEN, did not influence the proliferative effects of oncogene Wnt1 on HC11 cells. Further, LUN did not recapitulate GEN inhibitory effects on expansion of the cancer stem-like/progenitor population in MCF-7 cells. Results suggest the concerted actions of GEN and LUN on cellular apoptosis for potential mammary tumor preventive effects and highlight whole food consumption rather than intake of specific dietary supplements with limited biological effects for greater health benefits.

  18. Cell surface area and membrane folding in glioblastoma cell lines differing in PTEN and p53 status.

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    Simon Memmel

    Full Text Available Glioblastoma multiforme (GBM is characterized by rapid growth, invasion and resistance to chemo-/radiotherapy. The complex cell surface morphology with abundant membrane folds, microvilli, filopodia and other membrane extensions is believed to contribute to the highly invasive behavior and therapy resistance of GBM cells. The present study addresses the mechanisms leading to the excessive cell membrane area in five GBM lines differing in mutational status for PTEN and p53. In addition to scanning electron microscopy (SEM, the membrane area and folding were quantified by dielectric measurements of membrane capacitance using the single-cell electrorotation (ROT technique. The osmotic stability and volume regulation of GBM cells were analyzed by video microscopy. The expression of PTEN, p53, mTOR and several other marker proteins involved in cell growth and membrane synthesis were examined by Western blotting. The combined SEM, ROT and osmotic data provided independent lines of evidence for a large variability in membrane area and folding among tested GBM lines. Thus, DK-MG cells (wild type p53 and wild type PTEN exhibited the lowest degree of membrane folding, probed by the area-specific capacitance C m = 1.9 µF/cm(2. In contrast, cell lines carrying mutations in both p53 and PTEN (U373-MG and SNB19 showed the highest C m values of 3.7-4.0 µF/cm(2, which corroborate well with their heavily villated cell surface revealed by SEM. Since PTEN and p53 are well-known inhibitors of mTOR, the increased membrane area/folding in mutant GBM lines may be related to the enhanced protein and lipid synthesis due to a deregulation of the mTOR-dependent downstream signaling pathway. Given that membrane folds and extensions are implicated in tumor cell motility and metastasis, the dielectric approach presented here provides a rapid and simple tool for screening the biophysical cell properties in studies on targeting chemo- or radiotherapeutically the

  19. The mechanism involved in the loss of PTEN expression in NSCLC tumor cells

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    Li, Gang; Zhao, Jingfeng; Peng, Xianjing [Department of Radiology, Xiangya Hospital, Central South University, Changsha 410008 (China); Liang, Jian; Deng, Xin [Ruikang Hospital, Guangxi University of Traditional Chinese Medicine, Nanning 530003 (China); Chen, Yuxiang, E-mail: chenyx008@yahoo.cn [Department of Radiology, Xiangya Hospital, Central South University, Changsha 410008 (China); School of Biological Science and Technology, Central South University, Changsha 410008 (China)

    2012-02-17

    Highlights: Black-Right-Pointing-Pointer Radiation stimulates PTEN reexpression in NSCLC independent of p53 activation. Black-Right-Pointing-Pointer PTEN reexpression is mediated by miR-29b overexpression. Black-Right-Pointing-Pointer miR-29b regulates Dnmts expression in NSCLC tumor cells. Black-Right-Pointing-Pointer Target therapy could be established by overexpressing miR-29b expression. -- Abstract: Loss of PTEN expression is observed in most non-small cell lung cancers (NSCLC). However, the mechanism by which PTEN expression is regulated in NSCLC has not been fully elucidated. In this study, we investigated the role of DNA methyltransferases (Dnmts), microRNA-29b (miR-29b), and anti-miR-29b inhibitor in PTEN promoter methylation and PTEN gene expression in H358 NSCLC cells in vitro and in vivo. PTEN mRNA was measured by RT-PCR. PTEN and Dnmts protein levels were measured by Western blot. miR-29b expression was detected by Northern blot. A xenograft H358 tumor mouse model was established by subcutaneously inoculating H358 cells into the right hind limbs of nude mice. We found that radiation induced cell apoptosis and hypomethylation in PTEN promoter, PTEN and miR-29b expression, and downregulation of Dnmt1, 3a and 3b expression in H358 tumor cells. The effect of radiation on gene expression and apoptosis was blocked by anti-miR-29b inhibitor. In the xenograft H358 tumor model, anti-miR-29b inhibitor reversed radiation-induced tumor growth delay, PTEN reexpression and downregulation of Dnmts expression. Our study suggested that miR-29b is an upstream molecule of PTEN. miR-29b regulates PTEN gene expression through downregulating Dnmts expression and subsequently induces hypomethylation in PTEN promoter. Targeting therapy could be established in NSCLC by upregulating miR-29b expression.

  20. Antitumor activity of rapamycin in a Phase I trial for patients with recurrent PTEN-deficient glioblastoma.

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    Tim F Cloughesy

    2008-01-01

    Full Text Available BACKGROUND: There is much discussion in the cancer drug development community about how to incorporate molecular tools into early-stage clinical trials to assess target modulation, measure anti-tumor activity, and enrich the clinical trial population for patients who are more likely to benefit. Small, molecularly focused clinical studies offer the promise of the early definition of optimal biologic dose and patient population. METHODS AND FINDINGS: Based on preclinical evidence that phosphatase and tensin homolog deleted on Chromosome 10 (PTEN loss sensitizes tumors to the inhibition of mammalian target of rapamycin (mTOR, we conducted a proof-of-concept Phase I neoadjuvant trial of rapamycin in patients with recurrent glioblastoma, whose tumors lacked expression of the tumor suppressor PTEN. We aimed to assess the safety profile of daily rapamycin in patients with glioma, define the dose of rapamycin required for mTOR inhibition in tumor tissue, and evaluate the antiproliferative activity of rapamycin in PTEN-deficient glioblastoma. Although intratumoral rapamycin concentrations that were sufficient to inhibit mTOR in vitro were achieved in all patients, the magnitude of mTOR inhibition in tumor cells (measured by reduced ribosomal S6 protein phosphorylation varied substantially. Tumor cell proliferation (measured by Ki-67 staining was dramatically reduced in seven of 14 patients after 1 wk of rapamycin treatment and was associated with the magnitude of mTOR inhibition (p = 0.0047, Fisher exact test but not the intratumoral rapamycin concentration. Tumor cells harvested from the Ki-67 nonresponders retained sensitivity to rapamycin ex vivo, indicating that clinical resistance to biochemical mTOR inhibition was not cell-intrinsic. Rapamycin treatment led to Akt activation in seven patients, presumably due to loss of negative feedback, and this activation was associated with shorter time-to-progression during post-surgical maintenance rapamycin

  1. TMPRSS2-ERG and PTEN loss in prostate cancer.

    Science.gov (United States)

    Squire, Jeremy A

    2009-05-01

    Two studies show that the common recurrent gene fusion between TMPRSS2 and ERG promotes prostate cancer in both mouse and humans when PTEN is concurrently lost. In human prostate cancer, the presence of both these aberrations may be indicative of poor prognosis, suggesting that preclinical therapeutic research should target both of these pathways.

  2. Promoting axon regeneration in the adult CNS by modulation of the PTEN/mTOR pathway.

    Science.gov (United States)

    Park, Kevin Kyungsuk; Liu, Kai; Hu, Yang; Smith, Patrice D; Wang, Chen; Cai, Bin; Xu, Bengang; Connolly, Lauren; Kramvis, Ioannis; Sahin, Mustafa; He, Zhigang

    2008-11-07

    The failure of axons to regenerate is a major obstacle for functional recovery after central nervous system (CNS) injury. Removing extracellular inhibitory molecules results in limited axon regeneration in vivo. To test for the role of intrinsic impediments to axon regrowth, we analyzed cell growth control genes using a virus-assisted in vivo conditional knockout approach. Deletion of PTEN (phosphatase and tensin homolog), a negative regulator of the mammalian target of rapamycin (mTOR) pathway, in adult retinal ganglion cells (RGCs) promotes robust axon regeneration after optic nerve injury. In wild-type adult mice, the mTOR activity was suppressed and new protein synthesis was impaired in axotomized RGCs, which may contribute to the regeneration failure. Reactivating this pathway by conditional knockout of tuberous sclerosis complex 1, another negative regulator of the mTOR pathway, also leads to axon regeneration. Thus, our results suggest the manipulation of intrinsic growth control pathways as a therapeutic approach to promote axon regeneration after CNS injury.

  3. Adiponectin haploinsufficiency promotes mammary tumor development in MMTV-PyVT mice by modulation of phosphatase and tensin homolog activities.

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    Janice B B Lam

    Full Text Available BACKGROUND: Adiponectin is an adipokine possessing beneficial effects on obesity-related medical complications. A negative association of adiponectin levels with breast cancer development has been demonstrated. However, the precise role of adiponectin deficiency in mammary carcinogenesis remains elusive. METHODOLOGY/PRINCIPAL FINDINGS: In the present study, MMTV-polyomavirus middle T antigen (MMTV-PyVT transgenic mice with reduced adiponectin expressions were established and the stromal effects of adiponectin haploinsufficiency on mammary tumor development evaluated. In mice from both FVB/N and C57BL/6J backgrounds, insufficient adiponectin production promoted mammary tumor onset and development. A distinctive basal-like subtype of tumors, with a more aggressive phenotype, was derived from adiponectin haplodeficient MMTV-PyVT mice. Comparing with those from control MMTV-PyVT mice, the isolated mammary tumor cells showed enhanced tumor progression in re-implanted nude mice, accelerated proliferation in primary cultures, and hyperactivated phosphatidylinositol-3-kinase (PI3K/Akt/beta-catenin signaling, which at least partly attributed to the decreased phosphatase and tensin homolog (PTEN activities. Further analysis revealed that PTEN was inactivated by a redox-regulated mechanism. Increased association of PTEN-thioredoxin complexes was detected in tumors derived from mice with reduced adiponectin levels. The activities of thioredoxin (Trx1 and thioredoxin reductase (TrxR1 were significantly elevated, whereas treatment with either curcumin, an irreversible inhibitor of TrxR1, or adiponectin largely attenuated their activities and resulted in the re-activation of PTEN in these tumor cells. Moreover, adiponectin could inhibit TrxR1 promoter-mediated transcription and restore the mRNA expressions of TrxR1. CONCLUSION: Adiponectin haploinsufficiency facilitated mammary tumorigenesis by down-regulation of PTEN activity and activation of PI3K

  4. Heterozygosity for Pten promotes tumorigenesis in a mouse model of medulloblastoma.

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    Robert C Castellino

    Full Text Available BACKGROUND: Recent publications have described an important role for cross talk between PI-3 kinase and sonic hedgehog signaling pathways in the pathogenesis of medulloblastoma. METHODOLOGY/PRINCIPAL FINDINGS: We crossed mice with constitutive activation of Smoothened, SmoA1, with Pten deficient mice. Both constitutive and conditional Pten deficiency doubled the incidence of mice with symptoms of medulloblastoma and resulted in decreased survival. Analysis revealed a clear separation of gene signatures, with up-regulation of genes in the PI-3 kinase signaling pathway, including downstream activation of angiogenesis in SmoA1+/-; Pten +/- medulloblastomas. Western blotting and immunohistochemistry confirmed reduced or absent Pten, Akt activation, and increased angiogenesis in Pten deficient tumors. Down-regulated genes included genes in the sonic hedgehog pathway and tumor suppressor genes. SmoA1+/-; Pten +/+ medulloblastomas appeared classic in histology with increased proliferation and diffuse staining for apoptosis. In contrast, Pten deficient tumors exhibited extensive nodularity with neuronal differentiation separated by focal areas of intense staining for proliferation and virtually absent apoptosis. Examination of human medulloblastomas revealed low to absent PTEN expression in over half of the tumors. Kaplan-Meier analysis confirmed worse overall survival in patients whose tumor exhibited low to absent PTEN expression. CONCLUSIONS/SIGNIFICANCE: This suggests that PTEN expression is a marker of favorable prognosis and mouse models with activation of PI-3 kinase pathways may be important tools for preclinical evaluation of promising agents for the treatment of medulloblastoma.

  5. [Alkaline phosphatase in Amoeba proteus].

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    Sopina, V A

    2005-01-01

    In free-living Amoeba proteus (strain B), 3 phosphatase were found after disc-electrophoresis of 10 microg of protein in PAGE and using 1-naphthyl phosphate as a substrate a pH 9.0. These phosphatases differed in their electrophoretic mobilities - "slow" (1-3 bands), "middle" (one band) and "fast" (one band). In addition to 1-naphthyl phosphate, "slow" phosphatases were able to hydrolyse 2-naphthyl phosphate and p-nitrophenyl phosphate. They were slightly activated by Mg2+, completely inhibited by 3 chelators (EDTA, EGTA and 1,10-phenanthroline), L-cysteine, sodium dodecyl sulfate and Fe2+, Zn2+ and Mn2+ (50 mM), considerably inactivated by orthovanadate, molybdate, phosphatase inhibitor cocktail 1, p-nitrophenyl phosphate, Na2HPO4, DL-dithiothreitol and urea and partly inhibited by H2O2, DL-phenylalanine, 2-mercaptoethanol, phosphatase inhibitor cocktail 2 and Ca2+. Imidazole, L-(+)-tartrate, okadaic acid, NaF and sulfhydryl reagents -p-(hydroxy-mercuri)benzoate and N-ethylmaleimide - had no influence on the activity of "slow" phosphatases. "Middle" and "fast" phosphatases, in contrast to "slow" ones, were not inactivated by 3 chelators. The "middle" phosphatase differed from the "fast" one by smaller resistance to urea, Ca2+, Mn2+, phosphates and H2O2 and greater resistance to dithiothreitol and L-(+)-tartrate. In addition, the "fast" phosphatase was inhibited by L-cysteine but the "middle" one was activated by it. Of 5 tested ions (Mg2+, Cu2+, Mn2+, Ca2+ and Zn2+), only Zn2+ reactivated "slow" phosphatases after their inactivation by EDTA treatment. The reactivation of apoenzyme was only partial (about 35 %). Thus, among phosphatases found in amoebae at pH 9.0, only "slow" ones are Zn-metalloenzymes and may be considered as alkaline phosphatases (EC 3.1.3.1). It still remains uncertain, to which particular phosphatase class "middle" and "fast" phosphatases (pH 9.0) may belong.

  6. CDX2 Inhibits Invasion and Migration of Gastric Cancer Cells by Phosphatase and Tensin Homologue Deleted from Chromosome 10/Akt Signaling Pathway

    Institute of Scientific and Technical Information of China (English)

    Yong-Qiang Liu; Zhi-Gang Bai; Xue-Mei Ma; Zhong-Tao Zhang

    2015-01-01

    Background:Gastric cancer (GC) is one of the most prevalent malignancies in the world today,with a high mortality rate.CDX2 is a Drosophila caudal-related homeobox transcription factor that plays an important role in GC.Phosphatase and tensin homologue deleted from chromosome 10 (PTEN) is an important tumor suppressor which is widely expressed in normal human tissues.The aim of the study was to determine the relationship and mechanism between CDX2 and PTEN in invasion and migration of GC cells.Methods:pcDNA3-CDX2 plasmids were transfected into MGC-803 cells to up-regulate CDX2 protein,and small interfering RNA-CDX2 was transfected to down-regulate CDX2.The influence of CDX2 or PTEN on cell migration and invasion was measured by invasion,migration and wound healing assays.Western blotting assay and immunofluorescence were used to detect the expression ofCDX2,PTEN,phosphorylation ofAkt,E-cadherin and N-cadherin.Statistical significance was determined by one-way analysis of variance.Results:The results showed that CDX2 reduced the migration and invasion of GC cells (P < 0.05),and inhibited the activity of Akt through down-regulating PTEN expression (P < 0.05).CDX2 also restrained epithelial-mesenchymal transition of GC cells.Conclusions:CDX2 inhibited invasion and migration of GC cells by PTEN/Akt signaling pathway,and that may be used for potential therapeutic target.

  7. CLINICOPATHOLOGICAL SIGNIFICANCE OF PTEN AND CASPASE-3 EXPRESSIONS IN BREAST CANCER

    Institute of Scientific and Technical Information of China (English)

    Xue-fei Yang; Yan Xin; Li-li Mao

    2008-01-01

    Objective To investigate the expressions of PTEN and Caspase-3 proteins in human breast carcinoma, and to evaluate their clinicopathological implications during the tumorigenesis and progression of breast cancer.Methods The expressions of PTEN and Caspase-3 proteins in 95 cases of breast cancer and 15 cases of benignbreast diseases were investigated immunohistochemically. Correlations between the expression of PTEN protein,Caspase-3 protein, and clinicopathological features of breast cancers were analyzed.Results The loss expression rate of PTEN protein in tumor tissues was significantly higher than that in benignbreast diseases (33.7% vs. 0, P 0. 05). In addition,the expression of PTEN protein had significantly positive correlation with the expression of Caspase-3 protein in breast cancer (P <0.01 ).Conclusion The combination detection of PTEN and Caspase-3 may serve as an important index to estimate the pathobiological behavior and pognosis of breast cancer.

  8. Hydrocephalus caused by conditional ablation of the Pten or beta-catenin gene

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    Ohtoshi Akihira

    2008-10-01

    Full Text Available Abstract To investigate the roles of Pten and β-Catenin in the midbrain, either the Pten gene or the β-catenin gene was conditionally ablated, using Dmbx1 (diencephalon/mesencephalon-expressed brain homeobox gene 1-Cre mice. Homozygous disruption of the Pten or β-catenin gene in Dmbx1-expressing cells caused severe hydrocephalus and mortality during the postnatal period. Conditional deletion of Pten resulted in enlargement of midbrain structures. β-catenin conditional mutant mice showed malformation of the superior and inferior colliculi and stenosis of the midbrain aqueduct. These results demonstrate that both Pten and β-Catenin are essential for proper midbrain development, and provide the direct evidence that mutations of both Pten and β-catenin lead to hydrocephalus.

  9. Molecular cloning and characterization of PTEN in the orange-spotted grouper (Epinephelus coioides).

    Science.gov (United States)

    Luo, Sheng-Wei; Wang, Wei-Na; Xie, Ren-Chong; Xie, Fu-Xing; Kong, Jing-Rong; Xiao, Yu-Chao; Huang, Di; Sun, Zuo-Ming; Liu, Yuan; Wang, Cong

    2016-11-01

    PTEN is a key tumor suppressor gene that can play a regulatory role in the cellular proliferation, survival and apoptosis. In this study, the full-length PTEN (EcPTEN) was obtained, containing a 5'UTR of 745 bp, an ORF of 1269 bp and a 3'UTR of 106 bp. The EcPTEN gene encoded a polypeptide of 422 amino acids with an estimated molecular mass of 49.14 KDa and a predicted isoelectric point (pI) of 6.34. The deduced amino acid sequence analysis showed that EcPTEN comprised the conserved residues and the characteristic domains known to the critical functionality of PTEN. qRT-PCR analysis revealed that EcPTEN mRNA was broadly expressed in all the examined tissues, while the highest expression level was observed in liver, followed by the expression in blood, kidney, spleen, heart, gill, muscle and intestine. The groupers challenged with Vibrio alginolyticus showed a sharp increase of EcPTEN mRNA expression in immune tissues. In addition, western blotting analysis confirmed that the up-regulation of EcPTEN protein expression was steadily induced in liver. Subcellular localization analysis indicated that EcPTEN was localized in both nucleus and cytoplasm. Overexpression of EcPTEN can activate the apoptotic cascade and abrogate NF-kB, AP-1, Stat3 and Myc promoter activity in Hela cells. These results indicated that EcPTEN harboring highly-conserved domains with a close sequence similarity to those of PTP superfamily may disrupt the mammalian signalings and play a regulatory role in the apoptotic process.

  10. Adenovirus mediated homozygous endometrial epithelial Pten deletion results in aggressive endometrial carcinoma

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    Joshi, Ayesha; Ellenson, Lora Hedrick, E-mail: lora.ellenson@med.cornell.edu

    2011-07-01

    Pten is the most frequently mutated gene in uterine endometriod carcinoma (UEC) and its precursor complex atypical hyperplasia (CAH). Because the mutation frequency is similar in CAH and UEC, Pten mutations are thought to occur relatively early in endometrial tumorigenesis. Previous work from our laboratory using the Pten{sup +/-} mouse model has demonstrated somatic inactivation of the wild type allele of Pten in both CAH and UEC. In the present study, we injected adenoviruses expressing Cre into the uterine lumen of adult Pten floxed mice in an attempt to somatically delete both alleles of Pten specifically in the endometrium. Our results demonstrate that biallelic inactivation of Pten results in an increased incidence of carcinoma as compared to the Pten{sup +/-} mouse model. In addition, the carcinomas were more aggressive with extension beyond the uterus into adjacent tissues and were associated with decreased expression of nuclear ER{alpha} as compared to associated CAH. Primary cultures of epithelial and stromal cells were prepared from uteri of Pten floxed mice and Pten was deleted in vitro using Cre expressing adenovirus. Pten deletion was evident in both the epithelial and stromal cells and the treatment of the primary cultures with estrogen had different effects on Akt activation as well as Cyclin D3 expression in the two purified components. This study demonstrates that somatic biallelic inactivation of Pten in endometrial epithelium in vivo results in an increased incidence and aggressiveness of endometrial carcinoma compared to mice carrying a germline deletion of one allele and provides an important in vivo and in vitro model system for understanding the genetic underpinnings of endometrial carcinoma.

  11. Germline disruption of Pten localization causes enhanced sex-dependent social motivation and increased glial production.

    Science.gov (United States)

    Tilot, Amanda K; Gaugler, Mary K; Yu, Qi; Romigh, Todd; Yu, Wanfeng; Miller, Robert H; Frazier, Thomas W; Eng, Charis

    2014-06-15

    PTEN Hamartoma Tumor Syndrome (PHTS) is an autosomal-dominant genetic condition underlying a subset of autism spectrum disorder (ASD) with macrocephaly. Caused by germline mutations in PTEN, PHTS also causes increased risks of multiple cancers via dysregulation of the PI3K and MAPK signaling pathways. Conditional knockout models have shown that neural Pten regulates social behavior, proliferation and cell size. Although much is known about how the intracellular localization of PTEN regulates signaling in cancer cell lines, we know little of how PTEN localization influences normal brain physiology and behavior. To address this, we generated a germline knock-in mouse model of cytoplasm-predominant Pten and characterized its behavioral and cellular phenotypes. The homozygous Pten(m3m4) mice have decreased total Pten levels including a specific drop in nuclear Pten and exhibit region-specific increases in brain weight. The Pten(m3m4) model displays sex-specific increases in social motivation, poor balance and normal recognition memory-a profile reminiscent of some individuals with high functioning ASD. The cytoplasm-predominant protein caused cellular hypertrophy limited to the soma and led to increased NG2 cell proliferation and accumulation of glia. The animals also exhibit significant astrogliosis and microglial activation, indicating a neuroinflammatory phenotype. At the signaling level, Pten(m3m4) mice show brain region-specific differences in Akt activation. These results demonstrate that differing alterations to the same autism-linked gene can cause distinct behavioral profiles. The Pten(m3m4) model is the first murine model of inappropriately elevated social motivation in the context of normal cognition and may expand the range of autism-related behaviors replicated in animal models.

  12. PTEN encoding product: a marker for tumorigenesis and progression of gastric carcinoma

    Institute of Scientific and Technical Information of China (English)

    Lin Yang; Li-Ge Kuang; Hua-Chuan Zheng; Jin-Yi Li; Dong-Ying Wu; Su-Min Zhang; Yan Xin

    2003-01-01

    AIM: To detect the expression of PTEN encoding productin normal mucosa, intestinal metaplasia (IM), dysplasia andcarcinoma of the stomach, and to investigate its clinicalimplication in tumorigenesis and progression of gastriccarcinoma.METHODS: Formalin-fixed paraffin embedded specimens from184 cases of gastric carcinoma, their adjacent normal mucosa,IM and dysplasia were evaluated for PTEN protein expressionby SABC immunohistochemistry. PTEN expression wascompared with tumor stage, lymph node metastasis, Lauren'sand WHO's histological classification of gastric carcinoma.Expression of VEGF was also detected in 60 cases of gastriccarcinoma and its correlation with PTEN was concerned.RESULTS: The positive rates of PTEN protein were 100 %(102/102), 98.5 %(65/66), 66.7 % (4/6) and 47.8 %(88/184)in normal mucosa, IM, dysplasia and carcinoma of the stomach,respectively. The positive rates in dysplasia and carcinomawere lower than in normal mucosa and IM (P<0.01).Advanced gastric cancers expressed less frequent PTEN thanearly gastric cancer (42.9 % v567.6 %, P<0.01). The positiverate of PTEN protein was lower in gastric cancer with thanwithout lymph node metastasis (40.3 % v563.3 %, P<0.01).PTEN was less expressed in diffuse-type than in intestinal-type gastric cancer (41.5 % v557.8 %,P<0.05). Signet ringcell carcinoma showed the expression of PTEN at the lowestlevel (25.0 %, 7/28); less than well and moderatelydifferentiated ones (P<0.01). Expression of PTEN was notcorrelated with expression of VEGF (P>0.05).CONCLUSION: Loss or reduced expression of PTEN proteinoccures commonly in tumorigenesis and progression of gastriccarcinoma. It is suggested that PTEN can be an objective markerfor pathologically biological behaviors of gastric carcinoma.

  13. Voltage sensitive phosphatases: emerging kinship to protein tyrosine phosphatases from structure-function research

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    Kirstin eHobiger

    2015-02-01

    Full Text Available The transmembrane protein Ci-VSP from the ascidian Ciona intestinalis was described as first member of a fascinating family of enzymes, the voltage sensitive phosphatases (VSPs. Ci-VSP and its voltage-activated homologs from other species are stimulated by positive membrane potentials and dephosphorylate the head groups of negatively charged phosphoinositide phosphates (PIPs. In doing so, VSPs act as control centers at the cytosolic membrane surface, because they intervene in signaling cascades that are mediated by PIP lipids. The characteristic motif CX5RT/S in the active site classifies VSPs as members of the huge family of cysteine-based protein tyrosine phosphatases (PTPs. Although PTPs have already been well characterized regarding both, structure and function, their relationship to VSPs has drawn only limited attention so far. Therefore, the intention of this review is to give a short overview about the extensive knowledge about PTPs in relation to the facts known about VSPs. Here, we concentrate on the structural features of the catalytic domain which are similar between both classes of phosphatases and their consequences for the enzymatic function. By discussing results obtained from crystal structures, molecular dynamics simulations, and mutagenesis studies, a possible mechanism for the catalytic cycle of VSPs is presented based on that one proposed for PTPs. In this way, we want to link the knowledge about the catalytic activity of VSPs and PTPs.

  14. The chemosensitivity of cisplatin on cervical cancer Hela cells influenced by PTEN%PTEN影响宫颈癌Hela细胞对顺铂的化疗敏感性

    Institute of Scientific and Technical Information of China (English)

    范幸; 王比男; 李建军

    2012-01-01

    Objective:To investigate whether the chemosensitivity of cisplatin on cervical cancer Hela cell could be influenced by enhanced PTEN(phosphatase and tensin homology deletion on chromosome ten)expression from transfected PTEN vector.Methods: Three groups of Hela cell were cultured: blank control (non-trans-fection),plasmid control (Hela cells transfected with blank plasmid)and PTEN transfected cells (Hela cells transfected with plasmid contains PTEN gene).RT-PCR and Western blotting were used to detect and assess the expression level of the PTEN mRNA and protein in three groups of Hela cells respectively.Three groups of Hela cells were treated with different concentrations of cisplatin.MTT assay was used to assess chemosensitivity in three groups of Hela cells treated with cisplatin.RT-PCR was used to detect the expression level of phosphatidylinositol 3-kinase (PI3K)in three groups of Hela cell.Results:PTEN expression in PTEN transfected Hela cells was significantly higher than in other two groups(P<0.01).After treated with cisplatin,the growth inhibition ratio of PTEN transfected Hela cells was higher than other groups of cells (P<0.01).PI3K expression was significantly inhibited in PTEN transfected cells than the other two groups (P<0.01).Conclusion:PTEN could increase chemosensitivity of cisplatin on cervical cancer Hela cells,which could be induced by reducing drug resistance from inhibition of PI3K in Hela cells by PTEN.%目的:通过转染PTEN基因表达载体,提高宫颈癌Hela细胞中PTEN的表达水平,观察能否影响Hela细胞对顺铂的敏感性,并探讨其分子学机制.方法:将培养的宫颈癌Hela细胞分为空白对照(未转染质粒的Hela细胞)、质粒对照(转染空质粒的Hela细胞)和PTEN转染(转染PTEN表达载体的Hela细胞)3组.分别用RT-PCR和Western检测各组Hela细胞中PTEN的mRNA和蛋白的表达水平;MTT法检测各组Hela细胞对顺铂的化学敏感性;RT-PCR检测各组Hela细胞中磷脂酰肌醇3-

  15. Ursolic acid attenuates diabetic mesangial cell injury through the up-regulation of autophagy via miRNA-21/PTEN/Akt/mTOR suppression.

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    Xinxing Lu

    Full Text Available To investigate the effect of ursolic acid on autophagy mediated through the miRNA-21-targeted phosphoinositide 3 kinase (PI3K/protein kinase B (Akt/mammalian target of rapamycin (mTOR pathway in rat mesangial cells cultured under high glucose (HG conditions.Rat glomerular mesangial cells were cultured under normal glucose, HG, HG with the PI3K inhibitor LY294002 or HG with ursolic acid conditions. Cell proliferation and hypertrophy were assayed using an MTT assay and the ratio of total protein to cell number, respectively. The miRNA-21 expression was detected using RT-qPCR. The expression of phosphatase and tensin homolog (PTEN/AKT/mTOR signaling signatures, autophagy-associated protein and collagen I was detected by western blotting and RT-qPCR. Autophagosomes were observed using electron microscopy.Compared with mesangial cells cultured under normal glucose conditions, the cells exposed to HG showed up-regulated miRNA-21 expression, down-regulated PTEN protein and mRNA expression, up-regulated p85PI3K, pAkt, pmTOR, p62/SQSTMI, and collagen I expression and down-regulated LC3II expression. Ursolic acid and LY294002 inhibited HG-induced mesangial cell hypertrophy and proliferation, down-regulated p85PI3K, pAkt, pmTOR, p62/SQSTMI, and collagen I expression and up-regulated LC3II expression. However, LY294002 did not affect the expression of miRNA-21 and PTEN. Ursolic acid down-regulated miRNA-21 expression and up-regulated PTEN protein and mRNA expression.Ursolic acid inhibits the glucose-induced up-regulation of mesangial cell miRNA-21 expression, up-regulates PTEN expression, inhibits the activation of PI3K/Akt/mTOR signaling pathway, and enhances autophagy to reduce the accumulation of the extracellular matrix and ameliorate cell hypertrophy and proliferation.

  16. Structural Genomics of Protein Phosphatases

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    Almo,S.; Bonanno, J.; Sauder, J.; Emtage, S.; Dilorenzo, T.; Malashkevich, V.; Wasserman, S.; Swaminathan, S.; Eswaramoorthy, S.; et al

    2007-01-01

    The New York SGX Research Center for Structural Genomics (NYSGXRC) of the NIGMS Protein Structure Initiative (PSI) has applied its high-throughput X-ray crystallographic structure determination platform to systematic studies of all human protein phosphatases and protein phosphatases from biomedically-relevant pathogens. To date, the NYSGXRC has determined structures of 21 distinct protein phosphatases: 14 from human, 2 from mouse, 2 from the pathogen Toxoplasma gondii, 1 from Trypanosoma brucei, the parasite responsible for African sleeping sickness, and 2 from the principal mosquito vector of malaria in Africa, Anopheles gambiae. These structures provide insights into both normal and pathophysiologic processes, including transcriptional regulation, regulation of major signaling pathways, neural development, and type 1 diabetes. In conjunction with the contributions of other international structural genomics consortia, these efforts promise to provide an unprecedented database and materials repository for structure-guided experimental and computational discovery of inhibitors for all classes of protein phosphatases.

  17. Glucose-6-phosphatase deficiency

    Directory of Open Access Journals (Sweden)

    Labrune Philippe

    2011-05-01

    Full Text Available Abstract Glucose-6-phosphatase deficiency (G6P deficiency, or glycogen storage disease type I (GSDI, is a group of inherited metabolic diseases, including types Ia and Ib, characterized by poor tolerance to fasting, growth retardation and hepatomegaly resulting from accumulation of glycogen and fat in the liver. Prevalence is unknown and annual incidence is around 1/100,000 births. GSDIa is the more frequent type, representing about 80% of GSDI patients. The disease commonly manifests, between the ages of 3 to 4 months by symptoms of hypoglycemia (tremors, seizures, cyanosis, apnea. Patients have poor tolerance to fasting, marked hepatomegaly, growth retardation (small stature and delayed puberty, generally improved by an appropriate diet, osteopenia and sometimes osteoporosis, full-cheeked round face, enlarged kydneys and platelet dysfunctions leading to frequent epistaxis. In addition, in GSDIb, neutropenia and neutrophil dysfunction are responsible for tendency towards infections, relapsing aphtous gingivostomatitis, and inflammatory bowel disease. Late complications are hepatic (adenomas with rare but possible transformation into hepatocarcinoma and renal (glomerular hyperfiltration leading to proteinuria and sometimes to renal insufficiency. GSDI is caused by a dysfunction in the G6P system, a key step in the regulation of glycemia. The deficit concerns the catalytic subunit G6P-alpha (type Ia which is restricted to expression in the liver, kidney and intestine, or the ubiquitously expressed G6P transporter (type Ib. Mutations in the genes G6PC (17q21 and SLC37A4 (11q23 respectively cause GSDIa and Ib. Many mutations have been identified in both genes,. Transmission is autosomal recessive. Diagnosis is based on clinical presentation, on abnormal basal values and absence of hyperglycemic response to glucagon. It can be confirmed by demonstrating a deficient activity of a G6P system component in a liver biopsy. To date, the diagnosis is most

  18. Glucose-6-phosphatase deficiency.

    Science.gov (United States)

    Froissart, Roseline; Piraud, Monique; Boudjemline, Alix Mollet; Vianey-Saban, Christine; Petit, François; Hubert-Buron, Aurélie; Eberschweiler, Pascale Trioche; Gajdos, Vincent; Labrune, Philippe

    2011-05-20

    Glucose-6-phosphatase deficiency (G6P deficiency), or glycogen storage disease type I (GSDI), is a group of inherited metabolic diseases, including types Ia and Ib, characterized by poor tolerance to fasting, growth retardation and hepatomegaly resulting from accumulation of glycogen and fat in the liver. Prevalence is unknown and annual incidence is around 1/100,000 births. GSDIa is the more frequent type, representing about 80% of GSDI patients. The disease commonly manifests, between the ages of 3 to 4 months by symptoms of hypoglycemia (tremors, seizures, cyanosis, apnea). Patients have poor tolerance to fasting, marked hepatomegaly, growth retardation (small stature and delayed puberty), generally improved by an appropriate diet, osteopenia and sometimes osteoporosis, full-cheeked round face, enlarged kydneys and platelet dysfunctions leading to frequent epistaxis. In addition, in GSDIb, neutropenia and neutrophil dysfunction are responsible for tendency towards infections, relapsing aphtous gingivostomatitis, and inflammatory bowel disease. Late complications are hepatic (adenomas with rare but possible transformation into hepatocarcinoma) and renal (glomerular hyperfiltration leading to proteinuria and sometimes to renal insufficiency). GSDI is caused by a dysfunction in the G6P system, a key step in the regulation of glycemia. The deficit concerns the catalytic subunit G6P-alpha (type Ia) which is restricted to expression in the liver, kidney and intestine, or the ubiquitously expressed G6P transporter (type Ib). Mutations in the genes G6PC (17q21) and SLC37A4 (11q23) respectively cause GSDIa and Ib. Many mutations have been identified in both genes,. Transmission is autosomal recessive. Diagnosis is based on clinical presentation, on abnormal basal values and absence of hyperglycemic response to glucagon. It can be confirmed by demonstrating a deficient activity of a G6P system component in a liver biopsy. To date, the diagnosis is most commonly confirmed

  19. Interleukin-18 augments growth ability of primary human melanocytes by PTEN inactivation through the AKT/NF-κB pathway.

    Science.gov (United States)

    Zhou, Jia; Shang, Jing; Song, Jing; Ping, Fengfeng

    2013-02-01

    Normal human skin relies on melanocytes to provide photoprotection and thermoregulation by producing melanin. The growth and behavior of melanocytes are controlled by many factors. Interleukin-18 (IL-18) is expressed in both immune and non-immune cells and participates in the adjustment of multitude cellular functions. Nonetheless, the regulative roles of IL-18 in melanogenesis and growth of melanocytes have not been explored. The present study was conducted to investigate the effects of IL-18 on melanocytes and elucidate the underlying mechanisms. We proved that IL-18 increased the tyrosinase activity and melanin content in normal human foreskin-derived epidermal melanocytes (NHEM). Treatment with IL-18 (20 ng/ml) enhanced the expression of c-Kit, microphtalmia-associated transcription factor (MITF) and its downstream tyrosinase-related protein 1 (TRP-1), and TRP-2. In addition, IL-18 induced NHEM migration at concentration of 20 ng/ml. These results indicated a promotive action of IL-18 on melanogenesis in NHEM. Our data revealed that IL-18 stimulated ERK1/2 and NF-κB activation, improved p-Akt, p70 S6K and anti-apoptotic Bcl-2 levels, and deactivated phosphatase and tensin homolog deleted on chromosome 10 (PTEN) in NHEM. Besides, IL-18 increased level of PTEN phosphorylation to protect NHEM from damage induced by H(2)O(2). These results in vitro showed the accommodation of IL-18 in melanocytes growth. Therefore, we suggested an important regulating action of IL-18 to melanogenesis and cell growth ability of skin melanocytes.

  20. Soy peptide lunasin induces pten-mediated apoptosis in human breast cancer cells

    Science.gov (United States)

    The tumor suppressor PTEN inhibits the AKT signaling pathway whose unrestrained activity underlies many human malignancies. Previously we showed that dietary intake of soy protein isolate (SPI) enhanced PTEN expression in mammary tissue of rats with lower NMU-induced mammary tumor incidence relative...

  1. Characterization of cryptic splicing in germline PTEN intronic variants in Cowden syndrome.

    Science.gov (United States)

    Chen, Hannah Jinlian; Romigh, Todd; Sesock, Kaitlin; Eng, Charis

    2017-10-01

    Germline mutations in the tumor-suppressor gene PTEN predispose to subsets of Cowden syndrome (CS), Bannayan-Riley-Ruvalcaba syndrome, and autism. Evidence-based classification of PTEN variants as either deleterious or benign is urgently needed for accurate molecular diagnosis and gene-informed genetic counseling. We studied 34 different germline PTEN intronic variants from 61 CS patients, characterized their PTEN mRNA processing, and analyzed PTEN expression and downstream readouts of P-AKT and P-ERK1/2. While we found that many mutations near splice junctions result in exon skipping, we also identified the presence of cryptic splicing that resulted in premature termination or a shift in isoform usage. PTEN protein expression is significantly lower in the group with splicing changes while P-AKT, but not P-ERK1/2, is significantly increased. Our observations of these PTEN intronic variants should contribute to the determination of pathogenicity of PTEN intronic variants and aid in genetic counseling. © 2017 The Authors. Human Mutation published by Wiley Periodicals, Inc.

  2. Cancer risk and genotype-phenotype correlations in PTEN hamartoma tumor syndrome

    NARCIS (Netherlands)

    Nieuwenhuis, M.H.; Kets, C.M.; Murphy-Ryan, M.; Yntema, H.G.; Evans, D.G.; Colas, C.; Moller, P.; Hes, F.J.; Hodgson, S.V.; Olderode-Berends, M.J.; Aretz, S.; Heinimann, K.; Garcia, E.B.; Douglas, F.; Spigelman, A.; Timshel, S.; Lindor, N.M.; Vasen, H.F.

    2014-01-01

    Patients with germline PTEN mutations are at high risk of developing benign and malignant tumours. We aimed to evaluate the cumulative risk of several types of cancer and of dysplastic cerebellar gangliocytoma (Lhermitte-Duclos disease, LDD). In addition, genotype-phenotype correlations in PTEN hama

  3. Systematic analysis of the PTEN 5' leader identifies a major AUU initiated proteoform.

    Science.gov (United States)

    Tzani, Ioanna; Ivanov, Ivaylo P; Andreev, Dmitri E; Dmitriev, Ruslan I; Dean, Kellie A; Baranov, Pavel V; Atkins, John F; Loughran, Gary

    2016-05-01

    Abundant evidence for translation within the 5' leaders of many human genes is rapidly emerging, especially, because of the advent of ribosome profiling. In most cases, it is believed that the act of translation rather than the encoded peptide is important. However, the wealth of available sequencing data in recent years allows phylogenetic detection of sequences within 5' leaders that have emerged under coding constraint and therefore allow for the prediction of functional 5' leader translation. Using this approach, we previously predicted a CUG-initiated, 173 amino acid N-terminal extension to the human tumour suppressor PTEN. Here, a systematic experimental analysis of translation events in the PTEN 5' leader identifies at least two additional non-AUG-initiated PTEN proteoforms that are expressed in most human cell lines tested. The most abundant extended PTEN proteoform initiates at a conserved AUU codon and extends the canonical AUG-initiated PTEN by 146 amino acids. All N-terminally extended PTEN proteoforms tested retain the ability to downregulate the PI3K pathway. We also provide evidence for the translation of two conserved AUG-initiated upstream open reading frames within the PTEN 5' leader that control the ratio of PTEN proteoforms.

  4. Downregulation of miR-382 by propranolol inhibits the progression of infantile hemangioma via the PTEN-mediated AKT/mTOR pathway.

    Science.gov (United States)

    Li, Dongfan; Li, Peng; Guo, Zhengtuan; Wang, Huaijie; Pan, Weikang

    2017-03-01

    Approximately 10% of infantile hemangiomas (IHs) are the most common vascular tumors affecting children and are characterized by rapid growth, and can have destructive, disfiguring and even life-threatening consequences. Currently, propranolol is considered to be a safe and effective treatment option for problematic proliferating IHs. Recent studies have also revealed that microRNAs (miRNAs or miRs) play important roles in the regulation of angiogenesis. In this study, XPTS‑1 cells were used as a hemangioma-derived endothelial cell line constructed in our laboratory. Through a series of experiments, we discovered that miR‑382 is a novel miRNA associated with IHs, which was overexpressed in XPTS‑1 cells and was conversely downregulated by treatment with propranolol. In addition, we found that miR‑382 contributes to the progression of IHs. Our results revealed that propranolol inhibited XPTS‑1 cell migration and proliferation, and promoted apoptosis, and these effects were reversed by the restoration of miR‑382 expression by transfection of the cells with an miR‑382 overexpression vector. Further experiments revealed that the above-mentioned effects were associated with the phosphatase and tensin homolog (PTEN)-mediated AKT/mammalian target of rapamycin (mTOR) signaling pathway. The expression of PTEN was upregulated, while that of p-AKT, p-mTOR and p-p70S6K was downregulated by propranolol; these effects were partly reversed by the overexpression of miR‑382. On the whole, our study identified that the downregulation of miR‑382 by propranolol inhibits the progression of IHs via the PTEN-mediated AKT/mTOR pathway.

  5. Effect of treatment with cadmium on kinetic properties of Na(+), K(+)-ATPase and glucose-6-phosphatase activity in rat liver microsomes a correlative study on influence of lipid/phospholipid make-up.

    Science.gov (United States)

    Modi, Hiren R; Patil, Nisha; Katyare, Surendra S

    2008-12-05

    Studies on Cd hepatotoxicity have focused mainly on induction of cytochrome P(450) system and related enzymes. In the present study young adult male rats given a single intra-peritoneal injection of Cd (0.84mg Cd/kg body weight) and effects on kinetic parameters rat liver microsomal Na(+), K(+)-ATPase and G6Pase were evaluated at the end of 1 month and 1 week. The substrate and temperature kinetics parameters were examined and attempts were made to seek correlation with changes in lipid/phospholipid profiles. The Na(+), K(+) ATPase activity decreased only in 1 week Cd-treated group but recovered at the end of 1 month. The activity resolved in two distinct kinetic components in control as well as the experimental groups. In 1 week Cd-treated group the K(m) value of both the components was unchanged, whereas V(max) value decreased. In 1-month Cd-treated group V(max) value only of component I increased. The catalytic efficiency of both the components was not affected in the experimental groups. In 1-week Cd-treated group the energy of activations at high-temperature range (E(H)) and low-temperature range (E(L)) decreased, whereas for 1-month Cd-treated group the energies of activations did not change. The G6Pase activity measured at 37 degrees C was high only in 1-month Cd-treated group. The activity resolved in two kinetically distinguishable components in control as well as in the experimental groups. K(m) value of component I decreased in both the Cd-treated groups. In 1-month Cd-treated group the V(max) value of component II increased. The catalytic efficiency of G6Pase was unchanged despite changes in K(m) and V(max). In 1-week Cd-treated group the E(H) and E(L) decreased, whereas only E(L) showed decrease in 1-month Cd-treated group. Cholesterol (CHL) content increased in both the Cd-treated groups. Content of lysophospholipid (Lyso), spinghomyelin (SPM) and phosphatidic acid (PA) increased, whereas phosphatidylcholine (PC) and phosphatidylserine (PS) decreased

  6. Advances in research of relationship between PTEN/Akt/CREB signaling pathway and nervous system damage caused by arsenic%PTEN/Akt/CREB信号通路与砷致神经系统损伤关系的研究进展

    Institute of Scientific and Technical Information of China (English)

    曲丽莎(综述); 孙殿军(审校)

    2016-01-01

    Arsenic pollution is a major public health problem worldwide. Many countries are threatened by arsenic poisoning for years and residents in endemic arseniasis areas suffer from the arsenic poisoning. More remarkable, researchers have pointed out that nervous system is the major target of arsenic. Though some possible theories of arsenic neurotoxicity have been proposed but the exact molecular mechanism is not clear yet. Exploring the exact mechanism is important, as we can antagonize arsenic neurotoxicity effectively. Previous evidences have shown that arsenic can influence the expressions of phosphatase and tensin homologue deleted on chromosome 10 (PTEN), protein kinase B (Akt) and cAMP-response element binding protein (CREB) in many tissues and organs, moreover, PTEN/Akt/CREB signaling pathway plays an important role in nervous system. Therefore, the dysfunction of PTEN/Akt/CREB signaling pathway induced by arsenic exposure is important to the research of the mechanism of arsenic neurotoxicity.%砷暴露是世界范围内的重要公共卫生问题。许多国家都一直受到砷中毒的威胁,地方性砷中毒病区的居民更是承受着疾病的痛苦。更值得注意的是,神经系统是砷中毒的靶器官。尽管已经存在一些关于砷神经毒性的可能理论,但确切的分子机制仍不明确。因此,明确发病机制,有效拮抗砷的神经毒性十分重要。有研究表明,砷可以影响许多组织及器官中的第10号染色体同源丢失性磷酸酶-张力蛋白(PTEN)、蛋白激酶B (Akt)和cAMP反应元件结合蛋白(CREB)的表达,并且PTEN/Akt/CREB信号通路在神经系统中发挥重要作用。因此,砷暴露引起的PTEN/Akt/CREB信号通路的变化对于研究砷神经毒性机制十分重要。

  7. Characterization of Heterogeneous Prostate Tumors in Targeted Pten Knockout Mice.

    Directory of Open Access Journals (Sweden)

    Hanneke Korsten

    Full Text Available Previously, we generated a preclinical mouse prostate tumor model based on PSA-Cre driven inactivation of Pten. In this model homogeneous hyperplastic prostates (4-5m developed at older age (>10m into tumors. Here, we describe the molecular and histological characterization of the tumors in order to better understand the processes that are associated with prostate tumorigenesis in this targeted mouse Pten knockout model. The morphologies of the tumors that developed were very heterogeneous. Different histopathological growth patterns could be identified, including intraductal carcinoma (IDC, adenocarcinoma and undifferentiated carcinoma, all strongly positive for the epithelial cell marker Cytokeratin (CK, and carcinosarcomas, which were negative for CK. IDC pattern was already detected in prostates of 7-8 month old mice, indicating that it could be a precursor stage. At more than 10 months IDC and carcinosarcoma were most frequently observed. Gene expression profiling discriminated essentially two molecular subtypes, denoted tumor class 1 (TC1 and tumor class 2 (TC2. TC1 tumors were characterized by high expression of epithelial markers like Cytokeratin 8 and E-Cadherin whereas TC2 tumors showed high expression of mesenchyme/stroma markers such as Snail and Fibronectin. These molecular subtypes corresponded with histological growth patterns: where TC1 tumors mainly represented adenocarcinoma/intraductal carcinoma, in TC2 tumors carcinosarcoma was the dominant growth pattern. Further molecular characterization of the prostate tumors revealed an increased expression of genes associated with the inflammatory response. Moreover, functional markers for senescence, proliferation, angiogenesis and apoptosis were higher expressed in tumors compared to hyperplasia. The highest expression of proliferation and angiogenesis markers was detected in TC2 tumors. Our data clearly showed that in the genetically well-defined PSA-Cre;Pten-loxP/loxP prostate tumor

  8. Construction and Expression of Human PTEN Tumor Suppressor Gene Recombinant Adenovirus Vector

    Institute of Scientific and Technical Information of China (English)

    CHEN Qingyong; WANG Chunyou; CHEN Daoda; CHEN Jianying; JIANG Chunfang; ZHENG Hai

    2006-01-01

    The recombinant defective adenovirus vector carrying human PTEN tumor suppres sor gene was constructed by using AdEasy-1 system and its expression was detected in human breast cancer cell line MDA-MB-468. Human PTEN cDNA was cloned into adenovirus shuttle plasmid pAdTrack-CMV to generate a recombinant plasmid pAdTrack-CMV-PTEN, then homologeous recombination was carried out in the E. coli BJ5183 by contransforming linearized shuttle vector with adenovirus backbone plasmid pAdEasy-1. The newly recombined defective adenovirus vector AdPTEN containing green fluorescent protein (GFP) was packaged and propagated in 293 cells. After being purified by cesium chloride gradient centrifugation, the adenovirus was transfected into human breast cancer cell line MDA-MB-468 in vitro. The expression of PTEN mRNA and protein in infected human breast cancer cell line MDA-MB-468 was detected by RT-PCR and Western blot respectively. The recombinant defective adenovirus vector carrying PTEN gene was constructed successfully. The viral titer of purified adenovirus was 2.5×1010 pfu/mL, and about 70 % breast cancer cells were infected with Ad PTEN when multiplicity of infection (MOI) reached 50. The exogenous PTEN mRNA and protein were expressed in MDA-MB-468 cells infected with Ad-PTEN by RT-PCR and Western blot. The recombinant defective adenovirus vector of PTEN gene was constructed successfully using AdEasy-1 system rapidly, which paved a sound foundation for gene study of breast cancer.

  9. The role of PTEN in chronic growth hormone-induced hepatic insulin resistance.

    Science.gov (United States)

    Gao, Yuan; Su, Peizhu; Wang, Chuqiong; Zhu, Kongqin; Chen, Xiaolan; Liu, Side; He, Jiman

    2013-01-01

    Chronic growth hormone (GH) therapy has been shown to cause insulin resistance, but the mechanism remains unknown. PTEN, a tumor suppressor gene, is a major negative regulator of insulin signaling. In this study, we explored the effect of chronic GH on insulin signaling in the context of PTEN function. Balb/c healthy mice were given recombinant human or bovine GH intraperitoneally for 3 weeks. We found that phosphorylation of Akt was significantly decreased in chronic GH group and the expression of PTEN was significantly increased. We further examined this effect in the streptozotocin-induced Type I diabetic mouse model, in which endogenous insulin secretion was disrupted. Insulin/PI3K/Akt signaling was impaired. However, different from the observation in healthy mice, the expression of PTEN did not increase. Similarly, PTEN expression did not significantly increase in chronic GH-treated mice with hypoinsulinemia induced by prolonged fasting. We conducted in-vitro experiments in HepG2 cells to validate our in-vivo findings. Long-term exposure to GH caused similar resistance of insulin/PI3K/Akt signaling in HepG2 cells; and over-expression of PTEN enhanced the impairment of insulin signaling. On the other hand, disabling the PTEN gene by transfecting the mutant PTEN construct C124S or siPTEN, disrupted the chronic GH induced insulin resistance. Our data demonstrate that PTEN plays an important role in chronic-GH-induced insulin resistance. These findings may have implication in other pathological insulin resistance.

  10. Molecular characterization and function of a PTEN gene from Litopenaeus vannamei after Vibrio alginolyticus challenge.

    Science.gov (United States)

    Xie, C-y; Kong, J-r; Zhao, C-s; Xiao, Y-c; Peng, T; Liu, Y; Wang, W-n

    2016-06-01

    PTEN, a tumor suppressor gene, suppresses cell survival, growth, apoptosis, cell migration and DNA damage repair by inhibiting the PI3K/AKT signaling pathway. In this study, the full-length Litopenaeus vannamei PTEN (LvPTEN) cDNA was obtained, containing a 5'UTR of 59bp, an ORF of 1269bp and a 3'UTR of 146bp besides the poly (A) tail. The PTEN gene encoded a protein of 422 amino acids with an estimated molecular mass of 48.3 KDa and a predicted isoelectric point (pI) of 7.6. Subcellular localization analysis revealed that LvPTEN was distributed in both cytoplasm and nucleus, and the tissue distribution patterns showed that LvPTEN was ubiquitously expressed in all the examined tissues. Vibrio alginolyticus challenge induced upregulation of LvPTEN expression. Moreover, RNAi knock-down of LvPTEN in vivo significantly increased the expression of LvAKT mRNA, while reducing that of the downstream apoptosis genes LvP53 and LvCaspase3. LvPTEN knock-down also caused a sharp increase in cumulative mortality, bacterial numbers, and DNA damage in the hemolymph of L. vannamei following V. alginolyticus challenge, together with a sharp decrease in the total hemocyte count (THC). These results suggested that LvPTEN may participate in apoptosis via the PI3K/AKT signaling pathway in L. vannamei, and play an important role in shrimp innate immunity.

  11. Mice lacking pten in osteoblasts have improved intramembranous and late endochondral fracture healing.

    Directory of Open Access Journals (Sweden)

    Travis A Burgers

    Full Text Available The failure of an osseous fracture to heal (development of a non-union is a common and debilitating clinical problem. Mice lacking the tumor suppressor Pten in osteoblasts have dramatic and progressive increases in bone volume and density throughout life. Since fracture healing is a recapitulation of bone development, we investigated the process of fracture healing in mice lacking Pten in osteoblasts (Ocn-cre(tg/+;Pten(flox/flox . Mid-diaphyseal femoral fractures induced in wild-type and Ocn-cre(tg/+;Pten(flox/flox mice were studied via micro-computed tomography (µCT scans, biomechanical testing, histological and histomorphometric analysis, and protein expression analysis. Ocn-cre(tg/+;Pten(flox/flox mice had significantly stiffer and stronger intact bones relative to controls in all cohorts. They also had significantly stiffer healing bones at day 28 post-fracture (PF and significantly stronger healing bones at days 14, 21, and 28 PF. At day 7 PF, the proximal and distal ends of the Pten mutant calluses were more ossified. By day 28 PF, Pten mutants had larger and more mineralized calluses. Pten mutants had improved intramembranous bone formation during healing originating from the periosteum. They also had improved endochondral bone formation later in the healing process, after mature osteoblasts are present in the callus. Our results indicate that the inhibition of Pten can improve fracture healing and that the local or short-term use of commercially available Pten-inhibiting agents may have clinical application for enhancing fracture healing.

  12. PTEN/PI3K/Akt/VEGF signaling and the cross talk to KRIT1, CCM2, and PDCD10 proteins in cerebral cavernous malformations.

    Science.gov (United States)

    Kar, Souvik; Samii, Amir; Bertalanffy, Helmut

    2015-04-01

    Cerebral cavernous malformations (CCM) are common vascular malformation of the brain and are associated with abnormal angiogenesis. Although the exact etiology and the underlying molecular mechanism are still under investigation, recent advances in the identification of the mutations in three genes and their interactions with different signaling pathways have shed light on our understanding of CCM pathogenesis. The phosphatidylinositol 3-kinase (PI3K)/Akt pathway is known to play a major role in angiogenesis. Studies have shown that the phosphatase and tensin homologue deleted on chromosome ten (PTEN), a tumor suppressor, is an antagonist regulator of the PI3K/Akt pathway and mediates angiogenesis by activating vascular endothelial growth factor (VEGF) expression. Here, we provide an update literature review on the current knowledge of the PTEN/PI3K/Akt/VEGF signaling in angiogenesis, more importantly in CCM pathogenesis. In addition to reviewing the current literatures, this article will also focus on the structural domain of the three CCM proteins and their interacting partners. Understanding the biology of these proteins with respect to their signaling counterpart will help to guide future research towards new therapeutic targets applicable for CCM treatment.

  13. Regulatory T cells ameliorate intracerebral hemorrhage-induced inflammatory injury by modulating microglia/macrophage polarization through the IL-10/GSK3β/PTEN axis.

    Science.gov (United States)

    Zhou, Kai; Zhong, Qi; Wang, Yan-Chun; Xiong, Xiao-Yi; Meng, Zhao-You; Zhao, Ting; Zhu, Wen-Yao; Liao, Mao-Fan; Wu, Li-Rong; Yang, Yuan-Rui; Liu, Juan; Duan, Chun-Mei; Li, Jie; Gong, Qiu-Wen; Liu, Liang; Yang, Mei-Hua; Xiong, Ao; Wang, Jian; Yang, Qing-Wu

    2017-03-01

    Inflammation mediated by the peripheral infiltration of inflammatory cells plays an important role in intracerebral hemorrhage (ICH) induced secondary injury. Previous studies have indicated that regulatory T lymphocytes (Tregs) might reduce ICH-induced inflammation, but the precise mechanisms that contribute to ICH-induced inflammatory injury remain unclear. Our results show that the number of Tregs in the brain increases after ICH. Inducing Tregs deletion using a CD25 antibody or Foxp3(DTR)-mice increased neurological deficient scores (NDS), the level of inflammatory factors, hematoma volumes, and neuronal degeneration. Meanwhile, boosting Tregs using a CD28 super-agonist antibody reduced the inflammatory injury. Furthermore, Tregs depletion shifted microglia/macrophage polarization toward the M1 phenotype while boosting Tregs shifted this transition toward the M2 phenotype. In vitro, a transwell co-culture model of microglia and Tregs indicated that Tregs changed the polarization of microglia, decreased the expression of MHC-II, IL-6, and TNF-α and increased CD206 expression. IL-10 originating from Tregs mediated the microglia polarization by increasing the expression of Glycogen Synthase Kinase 3 beta (GSK3β), which phosphorylates and inactivates Phosphatase and Tensin homologue (PTEN) in microglia, TGF-β did not participate in this conversion. Thus, Tregs ameliorated ICH-induced inflammatory injury by modulating microglia/macrophage polarization toward the M2 phenotype through the IL-10/GSK3β/PTEN axis.

  14. Administration of a PTEN inhibitor BPV(pic) attenuates early brain injury via modulating AMPA receptor subunits after subarachnoid hemorrhage in rats.

    Science.gov (United States)

    Chen, Yujie; Luo, Chunxia; Zhao, Mingyue; Li, Qiang; Hu, Rong; Zhang, John H; Liu, Zhi; Feng, Hua

    2015-02-19

    The aim of this study was to investigate whether the phosphatase and tensin homolog deleted on chromosome ten (PTEN) inhibitor dipotassium bisperoxo(pyridine-2-carboxyl) oxovanadate (BPV(pic)) attenuates early brain injury by modulating α-amino-3-hydroxy-5-methyl-4-isoxa-zolep-propionate (AMPA) receptor subunits after subarachnoid hemorrhage (SAH). A standard intravascular perforation model was used to produce the experimental SAH in Sprague-Dawley rats. BPV(pic) treatment (0.2mg/kg) was evaluated for effects on neurological score, brain water content, Evans blue extravasation, hippocampal neuronal death and AMPA receptor subunits alterations after SAH. We found that BPV(pic) is effective in attenuating BBB disruption, lowering edema, reducing hippocampal neural death and improving neurological outcomes. In addition, the AMPA receptor subunit GluR1 protein expression at cytomembrane was downregulated, whereas the expression of GluR2 and GluR3 was upregulated after BPV(pic) treatment. Our results suggest that PTEN inhibited by BPV(pic) plays a neuroprotective role in SAH pathophysiology, possibly by alterations in glutamate AMPA receptor subunits.

  15. Detecting PTEN and PI3K signaling in brain

    Science.gov (United States)

    Zhu, Guo; Baker, Suzanne J.

    2016-01-01

    Summary The central nervous system is comprised of multiple cell types including neurons, glia and other supporting cells that may differ dramatically in levels of signaling pathway activation. Immunohistochemistry in conjunction with drug interference are powerful tools that allow evaluation of signaling pathways in different cell types of the mouse central nervous system in vivo. Here we provide detailed protocols for immunohistochemistry to evaluate three essential components in the PI3K pathway in mouse brain: Pten, p-Akt and p-4ebp1, and for rapamycin treatment to modulate mTOR signaling in vivo. PMID:27033070

  16. Regulation of PtdIns(3,4,5)P3/Akt signalling by inositol polyphosphate 5-phosphatases.

    Science.gov (United States)

    Eramo, Matthew J; Mitchell, Christina A

    2016-02-01

    The phosphoinositide 3-kinase (PI3K) generated lipid signals, PtdIns(3,4,5)P3 and PtdIns(3,4)P2, are both required for the maximal activation of the serine/threonine kinase proto-oncogene Akt. The inositol polyphosphate 5-phosphatases (5-phosphatases) hydrolyse the 5-position phosphate from the inositol head group of PtdIns(3,4,5)P3 to yield PtdIns(3,4)P2. Extensive work has revealed several 5-phosphatases inhibit PI3K-driven Akt signalling, by decreasing PtdIns(3,4,5)P3 despite increasing cellular levels of PtdIns(3,4)P2. The roles that 5-phosphatases play in suppressing cell proliferation and transformation are slow to emerge; however, the 5-phosphatase PIPP [proline-rich inositol polyphosphate 5-phosphatase; inositol polyphosphate 5-phosphatase (INPP5J)] has recently been identified as a putative tumour suppressor in melanoma and breast cancer and SHIP1 [SH2 (Src homology 2)-containing inositol phosphatase 1] inhibits haematopoietic cell proliferation. INPP5E regulates cilia stability and INPP5E mutations have been implicated ciliopathy syndromes. This review will examine 5-phosphatase regulation of PI3K/Akt signalling, focussing on the role PtdIns(3,4,5)P3 5-phosphatases play in developmental diseases and cancer.

  17. Phosphatidate phosphatase regulates membrane phospholipid synthesis via phosphatidylserine synthase.

    Science.gov (United States)

    Carman, George M; Han, Gil-Soo

    2017-08-16

    The yeast Saccharomyces cerevisiae serves as a model eukaryote to elucidate the regulation of lipid metabolism. In exponentially growing yeast, a diverse set of membrane lipids are synthesized from the precursor phosphatidate via the liponucleotide intermediate CDP-diacylglycerol. As cells exhaust nutrients and progress into the stationary phase, phosphatidate is channeled via diacylglycerol to the synthesis of triacylglycerol. The CHO1-encoded phosphatidylserine synthase, which catalyzes the committed step in membrane phospholipid synthesis via CDP-diacylglycerol, and the PAH1-encoded phosphatidate phosphatase, which catalyzes the committed step in triacylglycerol synthesis are regulated throughout cell growth by genetic and biochemical mechanisms to control the balanced synthesis of membrane phospholipids and triacylglycerol. The loss of phosphatidate phosphatase activity (e.g., pah1Δ mutation) increases the level of phosphatidate and its conversion to membrane phospholipids by inducing Cho1 expression and phosphatidylserine synthase activity. The regulation of the CHO1 expression is mediated through the inositol-sensitive upstream activation sequence (UASINO), a cis-acting element for the phosphatidate-controlled Henry (Ino2-Ino4/Opi1) regulatory circuit. Consequently, phosphatidate phosphatase activity regulates phospholipid synthesis through the transcriptional regulation of the phosphatidylserine synthase enzyme. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Silymarin inhibits cervical cancer cell through an increase of phosphatase and tensin homolog.

    Science.gov (United States)

    Yu, Hann-Chin; Chen, Li-Jen; Cheng, Kai-Chun; Li, Ying-Xiao; Yeh, Ching-Hua; Cheng, Juei-Tang

    2012-05-01

    Silymarin is an active constituent contained in the seeds of the milk thistle plant and is widely used as a hepatic protection agent due to its antioxidant-like activity. In the present study we evaluated the potential action of silymarin against cervical cancer and investigated its mechanism of action. Treatment of cervical cancer cells (C-33A) with silymarin resulted in a significant decrease in cell viability. Silymarin induced apoptosis through the modulation of Bcl-2 family proteins and activation of caspase 3. Silymarin also inhibited the phosphorylation of Akt with an increase in expression of phosphatase and tensin homolog (PTEN). We also observed that silymarin suppressed C-33A cell invasion and wound-healing migration in a concentration-dependent manner. Western-blot analysis showed that silymarin significantly inhibited the expression of matrix metalloproteinase-9 (MMP-9) in C-33A cells. Furthermore, we applied siRNA to lower the PTEN gene, which diminished the anticancer actions of silymarin. Taken together, these results show that silymarin has the potential to suppress the survival, migration and invasion of C-33A cancer cells; thus, it could be developed as a promising agent for the treatment of cervical cancer in the future.

  19. Fine-Tuning of PI3K/AKT Signalling by the Tumour Suppressor PTEN Is Required for Maintenance of Flight Muscle Function and Mitochondrial Integrity in Ageing Adult Drosophila melanogaster.

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    Lawrence B Mensah

    Full Text Available Insulin/insulin-like growth factor signalling (IIS, acting primarily through the PI3-kinase (PI3K/AKT kinase signalling cassette, plays key evolutionarily conserved regulatory roles in nutrient homeostasis, growth, ageing and longevity. The dysfunction of this pathway has been linked to several age-related human diseases including cancer, Type 2 diabetes and neurodegenerative disorders. However, it remains unclear whether minor defects in IIS can independently induce the age-dependent functional decline in cells that accompany some of these diseases or whether IIS alters the sensitivity to other aberrant signalling. We identified a novel hypomorphic allele of PI3K's direct antagonist, Phosphatase and tensin homologue on chromosome 10 (Pten, in the fruit fly, Drosophila melanogaster. Adults carrying combinations of this allele, Pten5, combined with strong loss-of-function Pten mutations exhibit subtle or no increase in mass, but are highly susceptible to a wide range of stresses. They also exhibit dramatic upregulation of the oxidative stress response gene, GstD1, and a progressive loss of motor function that ultimately leads to defects in climbing and flight ability. The latter phenotype is associated with mitochondrial disruption in indirect flight muscles, although overall muscle structure appears to be maintained. We show that the phenotype is partially rescued by muscle-specific expression of the Bcl-2 homologue Buffy, which in flies, maintains mitochondrial integrity, modulates energy homeostasis and suppresses cell death. The flightless phenotype is also suppressed by mutations in downstream IIS signalling components, including those in the mechanistic Target of Rapamycin Complex 1 (mTORC1 pathway, suggesting that elevated IIS is responsible for functional decline in flight muscle. Our data demonstrate that IIS levels must be precisely regulated by Pten in adults to maintain the function of the highly metabolically active indirect flight

  20. 下调PTEN基因对偏头痛大鼠三叉神经节CREB的调节作用%Down-Regulation of PTEN Induced The Modulation of CREB in Trigeminal Ganglia of Migraine Rats

    Institute of Scientific and Technical Information of China (English)

    桂蓓; 申崇标; 陈力学; 周冀英; 谭戈

    2010-01-01

    本研究利用RNAi重组腺病毒(AdR-siPTEN)下调偏头痛大鼠三叉神经节的PTEN(phosphatase and tensin homolog deleted on chromosome ten)基因,探讨其对偏头痛大鼠行为学的影响,以及经Akt(serine-threonine kinase)信号途径对CREB(cAMP response element-binding protein)的调控情况.实验采用健康雄性SD大鼠,随机分为假手术组(Sham)、硝酸甘油模型组(GTN)、Ad-RFP非特异siRNA处理空载体对照组(Vehicle+GTN)、AdR-siPTEN下调组(AdR-siPTEN+GTN).用AdR-siPTEN重组腺病毒对大鼠进行预处理,然后通过硝酸甘油(glyceryl trinitrate,GTN)法建立大鼠偏头痛模型,进行大鼠挠头和爬笼次数的检测,并用RT-PCR和Western-blot法进行相关基因的mRNA和蛋白检测.结果表明,当PTEN基因表达下调时,有效缓解了偏头痛导致的挠头和爬笼行为,并激活Akt信号途径,增加其下游作用因子CREB的表达,进而可能经"PTEN/Akt/CREB"信号通路影响神经突触可塑性,参与了偏头痛的发病机制.

  1. Immunohistochemical expression of PTEN in normal, hyperplastic and endometrial carcinoma of endometrium

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    IzadiMood

    2008-08-01

    Full Text Available "nBackground: Endometrial carcinoma is the most common malignancy of the female genital tract. Different molecular alterations have been described in endometrioid endometrial carcinoma that, the most frequently altered gene is mutations of PTEN. Up to 50-83% of endometrioid carcinoma reveal altered PTEN characterized by loss of expression. In endometrial hyperplasia, which are precursors of endometrioid carcinoma, loss of PTEN expression is 30-63%."n"nMethods: Immunohistochemical staining was performed on 90 cases of endometrial curettage including: 30 proliferative endometrium, 30 hyperplastic endometrium and 30 endometroid carcinoma."n"nImmunohistochemical specimens were graded semiquatitatively by considering the percentage of staining with two cut-point 10% & 50% on the whole section for each specimen."n"nResults: loss of PTEN expression was observed 0%, 0%, 30% of 51.7% in proliferative, simple hyperplasia, complex hyperplasia and endometrioid carcinoma respectively with cut-point 10% and 0%, 5.3%, 30%, 52.2% in endometrioid carcinoma respectively with cut-point 50%. Also there was no difference in PTEN expression between atypical complex hyperplasia and endometrioid carcinoma but there was significant difference between simple hyperplasia and proliferative with endometrioid carcinoma & atypical complex hyperplasia."n"nConclusion: These results show loss of PTEN expression in endmetrioid carcinoma and no differences between endometrioid carcinoma and atypical complex hyperplasia. Therefore, assessment of PTEN expression by negative immunostaining and matched with routine hematoxylin and eosin stained can be a new tool for diagnosis of endometrioid carcinoma.

  2. Breast cancer risk and clinical implications for germline PTEN mutation carriers.

    Science.gov (United States)

    Ngeow, Joanne; Sesock, Kaitlin; Eng, Charis

    2017-08-01

    PTEN Hamartoma Tumor syndrome (PHTS) encompasses a clinical spectrum of heritable disorders including Cowden syndrome (CS), Bannayan-Riley-Ruvalcaba syndrome, and Proteus and Proteus-like syndrome that are associated with germline mutations in the PTEN tumor suppressor gene. Breast cancer risk estimates (67-85 %) for women with germline PTEN mutations are similar to those quoted for patients with germline mutations in the BRCA1/2 genes. With PTEN on several germline gene testing panels, finding PTEN mutations and variants have increased exponentially. PHTS can be differentiated from other hereditary cancer syndromes including Hereditary Breast Ovarian Cancer syndrome, Lynch syndrome, and hamartomatous polyposis syndromes based on personal as well as family history. However, many of the benign features of CS are common in the general population, making the diagnosis of CS challenging. Breast cancer patients with an identified germline PTEN mutation are at increased risk of endometrial, thyroid, renal, and colorectal cancers as well as a second breast cancer. Increased screening for the various component cancers as well as predictive testing in first-degree relatives is recommended. Prophylactic mastectomy may be considered especially if breast tissue is dense or if repeated breast biopsies have been necessary. Management of women with breast cancer suspected of CS who test negative for germline PTEN mutations should be managed as per a mutation carrier if she meets CS diagnostic criteria, and should be offered enrollment in research to identify other predisposition genes.

  3. Endogenous S-sulfhydration of PTEN helps protect against modification by nitric oxide

    Energy Technology Data Exchange (ETDEWEB)

    Ohno, Kazuki; Okuda, Kosaku; Uehara, Takashi, E-mail: uehara@pharm.okayama-u.ac.jp

    2015-01-02

    Highlights: • PTEN is S-sulfhydrated endogenously in SH-SY5Y human neuroblastoma cells. • Preventing this modification by knocking down CBS renders PTEN sensitive to NO. • pAkt levels are increased significantly in CBS siRNA-transfected cells. • H{sub 2}S functions as an endogenous regulator of PTEN in neuronal cells. - Abstract: Hydrogen sulfide (H{sub 2}S) is a gaseous regulatory factor produced by several enzymes, and plays a pivotal role in processes such as proliferation or vasodilation. Recent reports demonstrated the physiological and pathophysiological functions of H{sub 2}S in neurons. PTEN is a target of nitric oxide (NO) or hydrogen peroxide, and the oxidative modification of cysteine (Cys) residue(s) attenuates its enzymatic activity. In the present study, we assessed the effect of H{sub 2}S on the direct modification of PTEN and the resulting downstream signaling. A modified biotin switch assay in SH-SY5Y human neuroblastoma cells revealed that PTEN is S-sulfhydrated endogenously. Subsequently, site-directed mutagenesis demonstrated that both Cys71 and Cys124 in PTEN are targets for S-sulfhydration. Further, the knockdown of cystathionine β-synthetase (CBS) using siRNA decreased this modification in a manner that was correlated to amount of H{sub 2}S. PTEN was more sensitive to NO under these conditions. These results suggest that the endogenous S-sulfhydration of PTEN via CBS/H{sub 2}S plays a role in preventing the S-nitrosylation that would inhibition its enzymatic activity under physiological conditions.

  4. The significance of PTEN and AKT aberrations in pediatric T-cell acute lymphoblastic leukemia

    Science.gov (United States)

    Zuurbier, Linda; Petricoin, Emanuel F.; Vuerhard, Maartje J.; Calvert, Valerie; Kooi, Clarissa; Buijs-Gladdines, Jessica G.C.A.M.; Smits, Willem K.; Sonneveld, Edwin; Veerman, Anjo J.P.; Kamps, Willem A.; Horstmann, Martin; Pieters, Rob; Meijerink, Jules P.P.

    2012-01-01

    Background PI3K/AKT pathway mutations are found in T-cell acute lymphoblastic leukemia, but their overall impact and associations with other genetic aberrations is unknown. PTEN mutations have been proposed as secondary mutations that follow NOTCH1-activating mutations and cause cellular resistance to γ-secretase inhibitors. Design and Methods The impact of PTEN, PI3K and AKT aberrations was studied in a genetically well-characterized pediatric T-cell leukemia patient cohort (n=146) treated on DCOG or COALL protocols. Results PTEN and AKT E17K aberrations were detected in 13% and 2% of patients, respectively. Defective PTEN-splicing was identified in incidental cases. Patients without PTEN protein but lacking exon-, splice-, promoter mutations or promoter hypermethylation were present. PTEN/AKT mutations were especially abundant in TAL- or LMO-rearranged leukemia but nearly absent in TLX3-rearranged patients (P=0.03), the opposite to that observed for NOTCH1-activating mutations. Most PTEN/AKT mutant patients either lacked NOTCH1-activating mutations (P=0.006) or had weak NOTCH1-activating mutations (P=0.011), and consequently expressed low intracellular NOTCH1, cMYC and MUSASHI levels. T-cell leukemia patients without PTEN/AKT and NOTCH1-activating mutations fared well, with a cumulative incidence of relapse of only 8% versus 35% for PTEN/AKT and/or NOTCH1-activated patients (P=0.005). Conclusions PI3K/AKT pathway aberrations are present in 18% of pediatric T-cell acute lymphoblastic leukemia patients. Absence of strong NOTCH1-activating mutations in these cases may explain cellular insensitivity to γ-secretase inhibitors. PMID:22491738

  5. Interaction of IGF2 and PTEN in ( M alignant Breast T issues

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    Preetha J Shetty

    2012-07-01

    Full Text Available Background: Breast Cancer (BC is one of the leading malignancies affecting women worldwide. Epigenetic mechanisms regulate gene expression playing an important role in the pathophysiology of cancer. In the present study IGF2 and PTEN genes in AKT pathway were selected for evaluation. Objective: To investigate the role of methylation and interaction of IGF2 and PTEN and in the pathoetiology of BC. Methods: Paraffin embedded archival breast tumor and adjacent normal tissue samples were used for carrying out PCR based methylation assay, genomic PCR, immunohistochemistry and qRT PCR. Results: In-Silico study indicated the absence of hormone responsive elements in the promoters of the selected genes. Methylation results indicated significant loss of methylation in IGF2 exon 9 CpG cluster and significant gain of PTEN promoter methylation in tumors. Immunohistochemistry revealed enhanced cytoplasmic expression o f IGF2 protein (p< 0.0001 and decreased nuclear localization of PTEN protein (p=0.0069 in the breast tumors. RT-PCR results indicated an increased IGF2 (p=0.024 and decreased PTEN transcripts (p<0.0001 in the tumors. Conclusion: Increased IGF2 in normal tissues increases PTEN which acts as a negative regulator of AKT pathway in the cytoplasm controlling excessive proliferation while in tumors this regulation is lost. PTEN acts as a negative regulator of MAPK pathway in the nucleus, plays an important role in cell cycle arrest in normal breast tissue. Reduction of PTEN in tumor tissue affects this pathway leading to cell survival. IGF2 and PTEN have a role in breast cancer and these molecular factors can be used for targeting therapy in future.

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

    Institute of Scientific and Technical Information of China (English)

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

    2009-01-01

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

  7. MicroRNA-21 accelerates hepatocyte proliferation in vitro via PI3K/Akt signaling by targeting PTEN

    Energy Technology Data Exchange (ETDEWEB)

    Yan-nan, Bai [Department of Hepato-Biliary-Pancreatic Surgery, West China Hospital, Sichuan University, Chengdu 610041, Sichuan Province (China); Department of Hepatobiliary Surgery, Fujian Provincial Hospital, Provincial Clinical College of Fujian Medical University, Fuzhou 350001, Fujian Province (China); Zhao-yan, Yu; Li-xi, Luo; Jiang, Yi [Department of Hepato-Biliary-Pancreatic Surgery, West China Hospital, Sichuan University, Chengdu 610041, Sichuan Province (China); Qing-jie, Xia [Translational Neuroscience Center, West China Hospital/West China Medical School of Sichuan University, Chengdu 610041, Sichuan Province (China); Yong, Zeng, E-mail: yongzengmd@gmail.com [Department of Hepato-Biliary-Pancreatic Surgery, West China Hospital, Sichuan University, Chengdu 610041, Sichuan Province (China)

    2014-01-17

    Highlights: •miRNAs-expression patterns of primary hepatocytes under proliferative status. •miR-21 expression level peaked at 12 h after stimulated by EGF. •miR-21 drive rapid S phase entry of primary hepatocytes. •PI3K/Akt signaling was modulated via targeting PTEN by miR-21. -- Abstract: MicroRNAs (miRNAs) are involved in controlling hepatocyte proliferation during liver regeneration. In this study, we established the miRNAs-expression patterns of primary hepatocytes in vitro under stimulation of epidermal growth factor (EGF), and found that microRNA-21 (miR-21) was appreciably up-regulated and peaked at 12 h. In addition, we further presented evidences indicating that miR-21 promotes primary hepatocyte proliferation through in vitro transfecting with miR-21 mimics or inhibitor. We further demonstrated that phosphatidylinositol 3′-OH kinase (PI3K)/Akt signaling was altered accordingly, it is, by targeting phosphatase and tensin homologue deleted on chromosome 10, PI3K/Akt signaling is activated by miR-21 to accelerate hepatocyte rapid S-phase entry and proliferation in vitro.

  8. The drug-resistance to gefitinib in PTEN low expression cancer cells is reversed by irradiation in vitro

    Directory of Open Access Journals (Sweden)

    Zhao Lu-Jun

    2009-09-01

    Full Text Available Abstract Background Despite of the recent success of EGFR inhibitory agents, the primary drug-resistant becomes a major challenge for EGFR inhibitor therapies. PTEN gene is an important positive regulatory factor for response to EGFR inhibitor therapy. Low-expression of PTEN is clearly one of the important reasons why tumor cells resisted to tyrosine kinase inhibitors. Methods To investigate the drug-resistance reversal to gefitinb and the mechanism in PTEN low expression cells which radiated with X-rays in vitro, We demonstrated that H-157 lung cancer cells (low-expression of PTEN but phospho-EGFR overexpressed tumor cells exposed to X-rays. The PTEN expressions and radiosensitizing effects of tyrosine kinase inhibitor before and after irradiation were observed. The cell-survival rates were evaluated by colony-forming assays. The cell apoptosis was investigated using FCM. The expressions of phospho-EGFR and PTEN were determined by Western blot analysis. Results The results showed that the PTEN expressions were significantly enhanced by X-rays. Moreover, the cell growth curve and survival curve were down-regulated in the gefitinib-treated groups after irradiation. Meanwhile, the radiation-induced apoptosis of tumor cells was increased by inhibition of the EGFR through up-regulation of PTEN. Conclusion These results suggested that PTEN gene is an important regulator on TKI inhibition, and the resistance to tyrosine kinase inhibitors might be reversed by irradiation in PTEN low expression cancer cells.

  9. TORC1 regulates Pah1 phosphatidate phosphatase activity via the Nem1/Spo7 protein phosphatase complex.

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    Emmanuelle Dubots

    Full Text Available The evolutionarily conserved target of rapamycin complex 1 (TORC1 controls growth-related processes such as protein, nucleotide, and lipid metabolism in response to growth hormones, energy/ATP levels, and amino acids. Its deregulation is associated with cancer, type 2 diabetes, and obesity. Among other substrates, mammalian TORC1 directly phosphorylates and inhibits the phosphatidate phosphatase lipin-1, a central enzyme in lipid metabolism that provides diacylglycerol for the synthesis of membrane phospholipids and/or triacylglycerol as neutral lipid reserve. Here, we show that yeast TORC1 inhibits the function of the respective lipin, Pah1, to prevent the accumulation of triacylglycerol. Surprisingly, TORC1 regulates Pah1 in part indirectly by controlling the phosphorylation status of Nem1 within the Pah1-activating, heterodimeric Nem1-Spo7 protein phosphatase module. Our results delineate a hitherto unknown TORC1 effector branch that controls lipin function in yeast, which, given the recent discovery of Nem1-Spo7 orthologous proteins in humans, may be conserved.

  10. Prostatic acid phosphatase by radioimmunoassay

    Energy Technology Data Exchange (ETDEWEB)

    Lindholm, G.R.; Stirton, M.S.; Liedtke, R.J.; Batjer, J.D.

    1980-11-07

    Prostatic acid phosphatase values in 98 patients with prostatic carcinoma were measured by a commmercial radioimmunoassay (RIA) and by enzymatic assay. Forty-three carcinomas were staged by rigorous pathological criteria. Patients (N = 129) with benign prostatic hyperplasia were the control group. At 94% specificity, sensitivities of the RIA vs the enzymatic assay for clinically staged patients were as follows: stage A, 22% vs 6%; B, 29% vs 10%; C, 52% vs 38%; and D, 87% vs 80%. However, none of the seven patients with pathological stage A and B disease had a positive test result, and we suggest that variability in staging criteria accounts for the discrepant sensitivity claims reported. Prostatic acid phosphatase RIA should not be used for screening but as an adjunct for staging known prostatic carcinoma.

  11. Broccoli, PTEN deletion and prostate cancer: where is the link?

    Directory of Open Access Journals (Sweden)

    Bardelli Alberto

    2010-12-01

    Full Text Available Abstract The concept that vegetables and fruits are relevant sources of cancer-preventive substances is strongly supported by population studies. Among others, cruciferous vegetables like broccoli, cabbage, cauliflower and Brussels sprouts are thought to affect the development of various types of cancers and especially prostate tumors. Yet, the identification of the molecular mechanisms by which the 'active' compounds contained in these vegetables mediate their anticancer activity has historically lagged behind. Accordingly, direct laboratory evidence of how individual nutrients affect cancer genes and the pathways they control remains the major obstacle to progress in this research field. Here we review a recent report investigating the interaction between sulforaphane, a dietary isothiocyanate derived from broccoli, and expression of the PTEN tumor suppressor gene in pre malignant prostate tissue.

  12. Alkaline phosphatase of Physarum polycephalum is insoluble.

    Science.gov (United States)

    Furuhashi, Kiyoshi

    2008-02-01

    The plasmodia of Physarum polycephalum grow as multinucleated cells in the presence of sufficient humidity and nutriment. Under non-illuminating conditions, stresses such as low temperature or high concentrations of salts transform the plasmodia into spherules whereas dehydration induces sclerotization. Some phosphatases including protein phosphatase and acid phosphatase have been purified from the plasmodia, but alkaline phosphatase remains to be elucidated. Phosphatase of the plasmodia, spherules and sclerotia was visualized by electrophoresis gel-staining assay using 5-bromo-4-chloro-3-indolyl phosphate. Insoluble fractions of the sclerotia were abundant in phosphatase activity. The phosphatase which was extracted by nonionic detergent was subjected to column chromatography and preparative electrophoresis. Purified phosphatase showed the highest activity at pH 8.8, indicating that this enzyme belongs to alkaline phosphatase. The apparent molecular mass from sodium dodecyl sulfate-polyacrylamide gel electrophoresis under non-reducing condition was estimated to be 100 kDa whereas that under reducing was 105 kDa. An amount of 1% sodium dodecyl sulfate or 0.5 M NaCl had no effects on the activity although the phosphatase showed heat instability, Mg(2+)-dependency and sensitivity to 2-glycerophosphate or NaF. The extracting conditions and enzymatic properties suggest that this alkaline phosphatase which is in a membrane-bound form plays important roles in phosphate metabolism.

  13. The effects of antisense PTEN gene transfection on the growth and invasion of glioma cells

    Institute of Scientific and Technical Information of China (English)

    CHEN Hong-jie; ZHENG Zhao-cong; WANG Ru-mi; WANG Shou-sen; YANG Wei-zhong

    2006-01-01

    Objective:To study the effects of antisense PTEN gene on the growth and invasion of glioma cells. Methods:A pcDNA3. 1/Hygro (-) recombinant plasmid containing antisense PTEN gene fragment was constructed. Glioma cells of primary culture were transfected with antisense PTEN gene vector and stably transfected clones were selected. Then, the different growth and invasion abilities and the different MMP9 mRNA expressions of three kinds of cells were observed, including the transfected cells, untransfected cells and the cells transfected with empty vector. Results :The abilities of growth and invasion of the transfected cells and the expressions of MMP9 mRNA were obviously enhanced. Conclusion: Antisense PTEN gene could have a negative impact on the growth and invasion of primary culture glioma cells.

  14. Tnactivation of PTEN is associated with increased angiogenesis and VEGF overexpression in gastric cancer

    Institute of Scientific and Technical Information of China (English)

    Ye-Jiang Zhou; Yu-Xia Xiong; Xiao-Ting Wu; De Shi; Wei Fan; Tong Zhou; Yue-Chun Li; Xiong Huang

    2004-01-01

    AIM: To investigate the expression of PTEN/MMAC1/TEP1and vascular endothelial growth factor (VEGF), their roles in biologic behavior and angiogenesis and their association in gastric cancer.METHODS: Immunohistochemical staining was used to evaluate the expression of PTEN, VEGF and microvascular density (MVD) on paraffin-embedded sections in 70 patients with primary gastric cancer and 24 patients with chronic superficial gastritis (CSG). Expression of PTEN, VEGF and MVD were compared with clinicopathological features of gastric cancer. The relationship between expression of PTEN, VEGF and MVD as well as the relationship between PTEN and VEGF expression in caner cells were investigated.RESULTS: PTEN expression significantly decreased (t= 3.98,P<0.01) whereas both VEGF expression and MVD significant increased (t = 4.29 and 4.41, respectively, both P<0.01)in gastric cancer group compared with CSG group. PTEN expression was significantly down-regulated (t = 1.95,P<0.05) whereas VEGF expression (t = 2.37, P<0.05) and MVD (t = 3.28, P<0.01) was significantly up-regulated in advanced gastric cancer compared with early-stage gastric cancer. PTEN expression in gastric cancer showed a negative association with lymph node metastasis (t= 3.91, P<0.01),invasion depth (t= 1.95, P<0.05) and age (t= 4.69, P<0.01).MVD in PTEN-negative gastric cancer was significantly higher than that in PTEN-positive gastric cancer (t = 3.69,P<0.01), and there was a negative correlation between PTEN expression and MVD (γ = -0.363, P<0.05). VEGF expression was positively associated with invasion depth (especially with serosa invasion, t = 4.69, P<0.01), lymph node metastasis (t= 2.31, P<0.05) and TNM stage (t= 3.04,P<0.01). MVD in VEGF-positive gastric cancer was significantly higher than that in VEGF-negative gastric cancer (t = 4.62,P<0.01), and there was a positive correlation between VEGF expression of and MVD (γ = 0.512, P<0.05). VEGF expression in PTEN

  15. Expression and significance of PTEN and PCNA in human laryngeal squamous cell carcinoma

    Institute of Scientific and Technical Information of China (English)

    李长青; 文莲姬; 金春顺; 崔树勋

    2004-01-01

    Objective: To elucidate the expression and significance of PTEN and PCNA in human laryngeal squamous cell carcinoma. Methods: Immunochemical method was used to study 60 cases of laryngeal carcinoma, 20 cases of normal laryngeal tissues which were closely adjacent to carcinoma and 10 cases of normal laryngeal tissues. Results: It was showed that PTEN gene was expressed in 85 % laryngeal carcinoma tissues. The percentage of lymph node metastasis of laryngeal carcinoma which were negative or positive of PTEN protein was 77.8 % and 33.3 % respectively, and the difference was significance ( P < 0.05). Conclusion: Expression of PTEN in laryngeal carcinoma was different from that of normal laryngeal tissues. It may play a role but not important in the tumorigenesis and development of laryngeal carcinoma.

  16. DNA Mismatch Repair Deficiency Accelerates Endometrial Tumorigenesis in Pten Heterozygous Mice

    OpenAIRE

    Hong WANG; Douglas, Wayne; Lia, Marie; Edelmann, Winfried; Kucherlapati, Raju; Podsypanina, Katrina; Parsons, Ramon; Ellenson, Lora Hedrick

    2002-01-01

    PTEN mutation and microsatellite instability are two of the most common genetic alterations in uterine endometrioid carcinoma. Furthermore, previous studies have suggested an association between the two alterations, however the basis and consequence of the association is not understood. Recently it has been shown that 100% of female Pten+/− mice develop complex atypical hyperplasia by 32 weeks of age that progresses to endometrial carcinoma in ∼20 to 25% of mice at 40 weeks. In an attempt to ...

  17. Phosphatase and Tensin Homologue Genetic Polymorphisms and their Interactions with Viral Mutations on the Risk of Hepatocellular Carcinoma

    Institute of Scientific and Technical Information of China (English)

    Yan Du; Yu-Wei Zhang; Rui Pu; Xue Han; Jian-Ping Hu; Hong-Wei Zhang; Hong-Yang Wang

    2015-01-01

    Background:Chronic hepatitis B virus (HBV) infection is the major cause of hepatocellular carcinoma (HCC).Some HBV mutants and dysregulation of phosphatase and tensin homolog (PTEN) may promote the development of HCC synergistically.We aimed to test the effects of PTEN genetic polymorphisms and their interactions with important HBV mutations on the development of HCC in HBV-infected subjects.Methods:Quantitative polymerase chain reaction was applied to genotype PTEN polymorphisms (rs1234220,rs2299939,rs1234213) in 1012 healthy controls,302 natural clearance subjects,and 2011 chronic HBV-infected subjects including 1021 HCC patients.HBV mutations were determined by sequencing.The associations of PTEN polymorphisms and their interactions with HBV mutations with HCC risk were assessed using multivariate logistic regression analysis.Results:Rs 1234220 C allele was significantly associated with HCC risk compared to healthy controls (adjusted odds ratio [A OR] =1.35,95% confidence interval [CI] =1.07-1.69) and HCC-free HBV-infected subjects (AOR =1.27,95% CI =1.01-1.57).rs1234220 C allele was significantly associated with increased frequencies of HCC-risk A 1652G,C 1673T,and C 1730G mutations in genotype B HBV-infected subjects.Rs2299939 GT genotype was inversely associated with HCC risk in HBV-infected patients (AOR =0.75,95% CI =0.62-0.92).The interaction of rs2299939 variant genotypes (GT+TT) with A3054T mutation significantly increased HCC risk (AOR =2.41,95% CI =1.08-5.35);whereas its interaction with C3116T mutation significantly reduced HCC risk (AOR =0.34,95% CI =0.18-0.66).These significant effects were only evident in males after stratification.Conclusions:PTEN polymorphisms and their interactions with HBV mutations may contribute to hepatocarcinogenesis in males.The host-virus interactions are important in identifying HBV-infected subjects who are more likely to develop HCC.

  18. Pancreas-specific Pten deficiency causes partial resistance to diabetes and elevated hepatic AKT signaling

    Institute of Scientific and Technical Information of China (English)

    Zan Tong; Yan Fan; Weiqi Zhang; Jun Xu; Jing Cheng; Mingxiao Ding; Hongkui Deng

    2009-01-01

    PTEN, a negative regulator of the phosphatidylinositol-3-kinase/AKT pathway, is an important modulator of insu-lin signaling. To determine the metabolic function of pancreatic Pten, we generated pancreas-specific Pten knockout (PPKO) mice. PPKO mice had enlarged pancreas and elevated proliferation of acinar cells. They also exhibited hy-poglycemia, hypoinsulinemia, and altered amino metabolism. Notably, PPKO mice showed delayed onset of strepto-zotocin (STZ)-induced diabetes and sex-biased resistance to high-fat-diet (HFD)-induced diabetes. To investigate the mechanism for the resistance to HFD-induced hyperglycemia in PPKO mice, we evaluated AKT phosphorylation in major insulin-responsive tissues: the liver, muscle, and fat. We found that Pten loss in the pancreas causes the eleva-tion of AKT signaling in the liver. The phosphorylation of AKT and its downstream substrate GSK3β was increased in the liver of PPKO mice, while PTEN level was decreased without detectable excision of Pten allele in the liver of PPKO mice. Proteomics analysis revealed dramatically decreased level of 78-kDa glucose-regulated protein (GRP78) in the liver of PPKO mice, which may also contribute to the lower blood glucose level of PPKO mice fed with HFD. Together, our findings reveal a novel response in the liver to pancreatic defect in metabolic regulation, adding a new dimension to understanding diabetes resistance.

  19. Lipid Profile

    Science.gov (United States)

    ... AACC products and services. Advertising & Sponsorship: Policy | Opportunities Lipid Profile Share this page: Was this page helpful? Also ... as: Lipid Panel; Coronary Risk Panel Formal name: Lipid Profile Related tests: Cholesterol ; HDL Cholesterol ; LDL Cholesterol ; Triglycerides ; ...

  20. PTEN mutation analysis in two genetic subtypes of high-grade oligodendroglial tumors. PTEN is only occasionally mutated in one of the two genetic subtypes.

    Science.gov (United States)

    Jeuken, J W; Nelen, M R; Vermeer, H; van Staveren, W C; Kremer, H; van Overbeeke, J J; Boerman, R H

    2000-05-01

    We recently identified two genetic subtypes of high-grade oligodendroglial tumors (HG-OT): 1p-/19q- HG-OT are characterized by a loss of chromosome 1p32-36 (del(1)(p32-p36) and/or a del(19)(q13. 3); whereas +7/-10 HG-OT harbor a gain of chromosome 7 (+7) and/or a -10 without a loss of 1p32-36 and 19q13.3. Because a -10 and a +7 are most frequently detected in glioblastomas (GBM), the genotype of +7/-10 HG-OT suggests that these tumors are GBM with a prominent oligodendroglial phenotype rather than anaplastic oligodendrogliomas. PTEN is a tumor suppressor gene, located at 10q23.3, which is involved in tumor progression of GBM and other neoplasms. In this study, we screened for PTEN mutations in six low-grade oligodendroglial tumors (LG-OT), five 1p-/19q- HG-OT, seven +7/-10 HG-OT, and nine xenografted GBM. PTEN mutations were detected in none of the LG-OT and 1p-/19q- HG-OT, once in +7/-10 HG-OT, and frequently in GBM. As one of the +7/-10 HG-OT harbored a PTEN mutation, this demonstrates that PTEN can be involved in the oncogenesis of this genetic subtype of HG-OT. The lower frequency of PTEN mutations in +7/-10 HG-OT compared to GBM suggests that these tumors are of a distinct tumor type rather than GBM. Published by Elsevier Science Inc.

  1. EFFECTS OF MUTATION AND EXPRESSION OF PTEN GENE mRNA ON TUMORIGENESIS AND PROGRESSION OF EPITHELIAL OVARIAN CANCER

    Institute of Scientific and Technical Information of China (English)

    陈颖; 郑华川; 杨雪飞; 孙丽梅; 辛彦

    2004-01-01

    Objective To investigate the mutation and expression of tumor suppressor gene-PTEN mRNA and explore their roles in tumorigenesis and progression of ovarian cancer. Methods Mutated exon 5 of PTEN gene was examined in normal ovary (n = 5), ovarian cyst (n =5), ovarian borderline tumor (n=9), epithelial ovarian cancer (n=60), and ovarian cancer cell line (n= 1)by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP). mRNA expression of PTEN gene was evaluated in corresponding tissues and cell line by reverse transcription polymerase chain reaction(RT-PCR). The mutation and mRNA expression of PTEN gene were compared with clinicopathological features of ovarian cancer. Results Mutated exon 5 of PTEN gene was detected only in 5 (7.1%) cases of epithelial ovarian cancer. mRNA expression level of PTEN gene in ovarian borderline tumor or ovarian cancer was lower than that in normal ovary or ovarian cyst (P < 0.05). The level of PTEN gene mRNA expression was negatively correlated with clinicopathological staging of ovarian cancer, whereas positively correlated with histological differentiation (P < 0.05). mRNA expression level of PTEN gene in ovarian endometrioid cancer was significantly lower than that in ovarian serous or mucinous cancer (P < 0.05). Conclusions Mutation of PTEN gene occurs in ovarian cancer. Down-regulated expression of PTEN is probably an important molecular event in tumorigenesis of ovarian cancer. Abnormal expression of PTEN gene is involved in progression of ovarian cancer. Reduced expression of PTEN gene is closely associated with tumorigenesis and pathobiological behaviors of ovarian endometrioid cancer.

  2. A Critical Role of the PTEN/PDGF Signaling Network for the Regulation of Radiosensitivity in Adenocarcinoma of the Prostate

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, Michael, E-mail: mechristense@uwalumni.com [Department of Radiation Oncology, Wayne State University School of Medicine, Barbara Ann Karmanos Cancer Center, Detroit, Michigan (United States); Najy, Abdo J. [Department of Pathology, Wayne State University School of Medicine, Barbara Ann Karmanos Cancer Center, Detroit, Michigan (United States); Snyder, Michael; Movilla, Lisa S. [Department of Radiation Oncology, Wayne State University School of Medicine, Barbara Ann Karmanos Cancer Center, Detroit, Michigan (United States); Kim, Hyeong-Reh Choi [Department of Pathology, Wayne State University School of Medicine, Barbara Ann Karmanos Cancer Center, Detroit, Michigan (United States)

    2014-01-01

    Purpose: Loss or mutation of the phosphate and tensin homologue (PTEN) is a common genetic abnormality in prostate cancer (PCa) and induces platelet-derived growth factor D (PDGF D) signaling. We examined the role of the PTEN/PDGF axis on radioresponse using a murine PTEN null prostate epithelial cell model. Methods and Materials: PTEN wild-type (PTEN{sup +/+}) and PTEN knockout (PTEN{sup −/−}) murine prostate epithelial cell lines were used to examine the relationship between the PTEN status and radiosensitivity and also to modulate the PDGF D expression levels. PTEN{sup −/−} cells were transduced with a small hairpin RNA (shRNA) lentiviral vector containing either scrambled nucleotides (SCRM) or sequences targeted to PDGF D (shPDGF D). Tumorigenesis and morphogenesis of these cell lines were evaluated in vivo via subcutaneous injection of male nude mice and in vitro using Matrigel 3-dimensional (3D) culture. Effects of irradiation on clonogenic survival, cell migration, and invasion were measured with respect to the PTEN status and the PDGF D expression level. In addition, apoptosis and cell cycle redistribution were examined as potential mechanisms for differences seen. Results: PTEN{sup −/−} cells were highly tumorigenic in animals and effectively formed foci in 3D culture. Importantly, loss of PDGF D in these cell lines drastically diminished these phenotypes. Furthermore, PTEN{sup −/−} cells demonstrated increased clonogenic survival in vitro compared to PTEN{sup +/+}, and attenuation of PDGF D significantly reversed this radioresistant phenotype. PTEN{sup −/−} cells displayed greater migratory and invasive potential at baseline as well as after irradiation. Both the basal and radiation-induced migratory and invasive phenotypes in PTEN{sup −/−} cells required PDGF D expression. Interestingly, these differences were independent of apoptosis and cell cycle redistribution, as they showed no significant difference. Conclusions: We propose

  3. [Protein phosphatases: structure and function].

    Science.gov (United States)

    Bulanova, E G; Budagian, V M

    1994-01-01

    The process of protein and enzyme systems phosphorylation is necessary for cell growth, differentiation and preparation for division and mitosis. The conformation changes of protein as a result of phosphorylation lead to increased enzyme activity and enhanced affinity to substrates. A large group of enzymes--protein kinases--is responsible for phosphorylation process in cell, which are divided into tyrosine- and serine-threonine-kinases depending on their ability to phosphorylate appropriate amino acid residues. In this review has been considered the functional importance and structure of protein phosphatases--enzymes, which are functional antagonists of protein kinases.

  4. mTORC1 signalling mediates PI3K-dependent large lipid droplet accumulation in Drosophila ovarian nurse cells

    Directory of Open Access Journals (Sweden)

    Lawrence B. Mensah

    2017-05-01

    Full Text Available Insulin and insulin-like growth factor signalling (IIS, which is primarily mediated by the PI3-kinase (PI3K/PTEN/Akt kinase signalling cassette, is a highly evolutionarily conserved pathway involved in co-ordinating growth, development, ageing and nutrient homeostasis with dietary intake. It controls transcriptional regulators, in addition to promoting signalling by mechanistic target of rapamycin (mTOR complex 1 (mTORC1, which stimulates biosynthesis of proteins and other macromolecules, and drives organismal growth. Previous studies in nutrient-storing germline nurse cells of the Drosophila ovary showed that a cytoplasmic pool of activated phosphorylated Akt (pAkt controlled by Pten, an antagonist of IIS, cell-autonomously regulates accumulation of large lipid droplets in these cells at late stages of oogenesis. Here, we show that the large lipid droplet phenotype induced by Pten mutation is strongly suppressed when mTor function is removed. Furthermore, nurse cells lacking either Tsc1 or Tsc2, which negatively regulate mTORC1 activity, also accumulate large lipid droplets via a mechanism involving Rheb, the downstream G-protein target of TSC2, which positively regulates mTORC1. We conclude that elevated IIS/mTORC1 signalling is both necessary and sufficient to induce large lipid droplet formation in late-stage nurse cells, suggesting roles for this pathway in aspects of lipid droplet biogenesis, in addition to control of lipid metabolism.

  5. Variable expression of PIK3R3 and PTEN in Ewing Sarcoma impacts oncogenic phenotypes.

    Directory of Open Access Journals (Sweden)

    Brian F Niemeyer

    Full Text Available Ewing Sarcoma is an aggressive malignancy of bone and soft tissue affecting children and young adults. Ewing Sarcoma is driven by EWS/Ets fusion oncoproteins, which cause widespread alterations in gene expression in the cell. Dysregulation of receptor tyrosine kinase signaling, particularly involving IGF-1R, also plays an important role in Ewing Sarcoma pathogenesis. However, the basis of this dysregulation, including the relative contribution of EWS/Ets-dependent and independent mechanisms, is not well understood. In the present study, we identify variable expression of two modifiers of PI3K signaling activity, PIK3R3 and PTEN, in Ewing Sarcoma, and examine the consequences of this on PI3K pathway regulation and oncogenic phenotypes. Our findings indicate that PIK3R3 plays a growth-promotional role in Ewing Sarcoma, but suggest that this role is not strictly dependent on regulation of PI3K pathway activity. We further show that expression of PTEN, a well-established, potent tumor suppressor, is lost in a subset of Ewing Sarcomas, and that this loss strongly correlates with high baseline PI3K pathway activity in cell lines. In support of functional importance of PTEN loss in Ewing Sarcoma, we show that re-introduction of PTEN into two different PTEN-negative Ewing Sarcoma cell lines results in downregulation of PI3K pathway activity, and sensitization to the IGF-1R small molecule inhibitor OSI-906. Our findings also suggest that PTEN levels may contribute to sensitivity of Ewing Sarcoma cells to the microtubule inhibitor vincristine, a relevant chemotherapeutic agent in this cancer. Our studies thus identify PIK3R3 and PTEN as modifiers of oncogenic phenotypes in Ewing Sarcoma, with potential clinical implications.

  6. PTEN coding product:a new marker for tumorigenesis and progession of endometrial carcinoma

    Institute of Scientific and Technical Information of China (English)

    Gao Qinglei; Li Jing; Xing Hui; Lu Yunping; Zhou Jianfeng; Ma Ding

    2008-01-01

    Objective :To investigate the expression of PTEN in carcinogenesis and development of endometrial carcinoma.Methods: The expression of PTEN was detected by reverse transcription-polymerase chain reaction(RT-PCR) methods from 24 cases with endometrial carcinoma,10 cases with endometrial atypical hyperplasia,I0 eases with endometrial hyperplasia and I0 cases with normal endometrium and by SP immunohistochemical methods from 73 cases with endometrial carcinoma,25 cases with endometrial atypical hyperplasia,71 cases with endometrial hyperplasia and 31 cases with normal endometrium.Results:PTEN expression of both RNA and protein in patients with endometrial carcinoma and endometrial atypical hyperplasia was significantly lower than that of patients with endometrial hyperplasia and normal endometriurn.mRNA relative value was 0.35±0.13,0.46±0.11,2.32±0.32,2.45±0.51,respectively.Loss of PTEN expression rates were 66.67% (38/57) ,76.00% ( 19/25 ) ,5.63% (4/71 ) ,0 (0/31 ),repeetively.The results were also compared with clinical parameters.Loss of PTEN expression in patients with endometrial carcinoma was significantly related to histological classification ( P < 0.0001 ) and differentiation ( P < 0.05 ).It was not related to depth of myometrium invasion and clinical stage( P >0.05 ).Conclusion:Loss of PTEN expression is an early event in endometrial tumorigenesis.Detection of PTEN protein may be a diagnostic biomarker for endometrial precancers and adenocareinoma.

  7. Cancer Prognosis Defined by the Combined Analysis of 8q, PTEN and ERG

    Directory of Open Access Journals (Sweden)

    Maria P. Silva

    2016-12-01

    Full Text Available Overtreatment is a major concern in men diagnosed with prostate cancer. The aim of this study was to evaluate the combined prognostic role of three frequent molecular alterations in prostate cancer, namely relative 8q gain, ERG overexpression, and loss of PTEN expression, in a series of 136 patients with prostate cancer treated with prostatectomy and with a long follow-up. Fluorescent in situ hybridization was used to detect the relative copy number of 8q and immunohistochemistry was used for quantitative assessment of ERG and PTEN expression. During a median follow-up period of 117.8 months, 66 (49% patients had disease recurrence. Relative 8q gain, ERG overexpression, and loss of PTEN expression were observed in 18%, 56%, and 33% of the cases, respectively. No association with patient recurrence-free survival was found for relative 8q gain or ERG overexpression on their own, whereas loss of PTEN expression was associated with worse recurrence-free survival (P = .006. Interestingly, in the subgroup of patients with normal PTEN expression, we found that the combined relative 8q gain/ERG overexpression is associated with high risk of recurrence (P = .008, suggesting that alternative mechanisms exist for progression into clinically aggressive disease. Additionally, in intermediate-risk patients with normal PTEN expression in their tumors, the combination of 8q gain/ERG overexpression was associated with a poor recurrence-free survival (P < .001, thus indicating independent prognostic value. This study shows that the combined analysis of 8q, ERG and PTEN contributes to an improved clinical outcome stratification of prostate cancer patients treated with radical prostatectomy.

  8. Expression and significance of PTEN, hypoxia-inducible factor-1 alpha in colorectal adenoma and adenocarcinoma

    Institute of Scientific and Technical Information of China (English)

    Ying-An Jiang; Li-Fang Fan; Chong-Qing Jiang; You-Yuan Zhang; He-Sheng Luo; Zhi-Jiao Tang; Dong Xia; Ming Wang

    2003-01-01

    AIM: To investigate the expression and significance of PTEN,hypoxia-inducible factor-1 alpha (HIF-1α), and targeting gene VEGF during colorectal carciogenesis.METHODS: Total 71 cases colorectal neoplasms (9 cases of colorectal adenoma and 62 colorectal adenocarcinoma)were formalin fixed and paraffin-embedded, and all specimens were evaluated for PTEN mRNA, HIF-1α mRNA and VEGF protein expression. PTEN mRNA, HIF-1α mRNA were detected by in situ hybridization. VEGF protein was identified by citrate-microwave SP immunohistochemical method.RESULTS: There were significant differences in PTEN, HIF1α and VEGF expression between colorectal adenomas and colorectal adenocarcinoma (P<0.05). The level of PTEN expression decreased as the pathologic stage increased.Conversely, HIF-1α and VEGF expression increased with the Dukes stage as follows: stage A (0.1029±0.0457:0.1207± 0.0436), stage B (0.1656±0.0329: 0.1572±0.0514),and stage C+D (0.2335±0.0748: 0.2219±0.0803). For PTEN expression, there was a significant difference among Dukes stage A, B, and C+D, and the level of PTEN expression was found to be significant higher in Dukes stage A or B than that of Dukes stage C or D. For HIF-1α expression,there was a significant difference between Dukes stage A and B, and the level of HIF-1α expression was found to be significantly higher in Dukes stage C+D than that of Dukes stage A or B. The VEGF expression had similar results as HIF-1α expression. In colorectal adenocarcinoma,decreased levels of PTEN were significantly associated with increased expression of HIF-1α mRNA (r=-0.36, P<0.05)and VEGF protein (r=-0.48, P<0.05) respectively. The levels of HIF-1 were positively correlated with VEGF expression (r=0.71, P<0.01).CONCLUSION: Loss of PTEN expression and increased levels of HIF-1α and VEGF may play an important role in carcinogenesis and progression of colorectal adenocarcinoma.

  9. Hydrogen sulfide prevents hydrogen peroxide-induced activation of epithelial sodium channel through a PTEN/PI(3,4,5)P3 dependent pathway.

    Science.gov (United States)

    Zhang, Jianing; Chen, Shuo; Liu, Huibin; Zhang, Bingkun; Zhao, Ying; Ma, Ke; Zhao, Dan; Wang, Qiushi; Ma, Heping; Zhang, Zhiren

    2013-01-01

    Sodium reabsorption through the epithelial sodium channel (ENaC) at the distal segment of the kidney plays an important role in salt-sensitive hypertension. We reported previously that hydrogen peroxide (H2O2) stimulates ENaC in A6 distal nephron cells via elevation of phosphatidylinositol 3,4,5-trisphosphate (PI(3,4,5)P3) in the apical membrane. Here we report that H2S can antagonize H2O2-induced activation of ENaC in A6 cells. Our cell-attached patch-clamp data show that ENaC open probability (PO ) was significantly increased by exogenous H2O2, which is consistent with our previous finding. The aberrant activation of ENaC induced by exogenous H2O2 was completely abolished by H2S (0.1 mM NaHS). Pre-treatment of A6 cells with H2S slightly decreased ENaC P(O); however, in these cells H2O2 failed to elevate ENaC PO . Confocal microscopy data show that application of exogenous H2O2 to A6 cells significantly increased intracellular reactive oxygen species (ROS) level and induced accumulation of PI(3,4,5)P3 in the apical compartment of the cell membrane. These effects of exogenous H2O2 on intracellular ROS levels and on apical PI(3,4,5)P3 levels were almost completely abolished by treatment of A6 cells with H2S. In addition, H2S significantly inhibited H2O2-induced oxidative inactivation of the tumor suppressor phosphatase and tensin homolog (PTEN) which is a negative regulator of PI(3,4,5)P3. Moreover, BPV(pic), a specific inhibitor of PTEN, elevated PI(3,4,5)P3 and ENaC activity in a manner similar to that of H2O2 in A6 cells. Our data show, for the first time, that H2S prevents H2O2-induced activation of ENaC through a PTEN-PI(3,4,5)P3 dependent pathway.

  10. Hydrogen sulfide prevents hydrogen peroxide-induced activation of epithelial sodium channel through a PTEN/PI(3,4,5P3 dependent pathway.

    Directory of Open Access Journals (Sweden)

    Jianing Zhang

    Full Text Available Sodium reabsorption through the epithelial sodium channel (ENaC at the distal segment of the kidney plays an important role in salt-sensitive hypertension. We reported previously that hydrogen peroxide (H2O2 stimulates ENaC in A6 distal nephron cells via elevation of phosphatidylinositol 3,4,5-trisphosphate (PI(3,4,5P3 in the apical membrane. Here we report that H2S can antagonize H2O2-induced activation of ENaC in A6 cells. Our cell-attached patch-clamp data show that ENaC open probability (PO was significantly increased by exogenous H2O2, which is consistent with our previous finding. The aberrant activation of ENaC induced by exogenous H2O2 was completely abolished by H2S (0.1 mM NaHS. Pre-treatment of A6 cells with H2S slightly decreased ENaC P(O; however, in these cells H2O2 failed to elevate ENaC PO . Confocal microscopy data show that application of exogenous H2O2 to A6 cells significantly increased intracellular reactive oxygen species (ROS level and induced accumulation of PI(3,4,5P3 in the apical compartment of the cell membrane. These effects of exogenous H2O2 on intracellular ROS levels and on apical PI(3,4,5P3 levels were almost completely abolished by treatment of A6 cells with H2S. In addition, H2S significantly inhibited H2O2-induced oxidative inactivation of the tumor suppressor phosphatase and tensin homolog (PTEN which is a negative regulator of PI(3,4,5P3. Moreover, BPV(pic, a specific inhibitor of PTEN, elevated PI(3,4,5P3 and ENaC activity in a manner similar to that of H2O2 in A6 cells. Our data show, for the first time, that H2S prevents H2O2-induced activation of ENaC through a PTEN-PI(3,4,5P3 dependent pathway.

  11. Prognostic Significance of mTOR and PTEN in Patients with Esophageal Squamous Cell Carcinoma

    Directory of Open Access Journals (Sweden)

    Jianjun Lu

    2015-01-01

    Full Text Available The prognostic value of mTOR in ESCC is much controversial; this study aimed to determine the prognostic importance of mTOR and PTEN in patients with ESCC. A total of 148 consecutive patients who underwent esophagectomy from 2010 to 2012 were included in this study, tested by western bolt and immunohistochemistry for mTOR and PTEN expression. Correlation coefficient was calculated using Pearson’s correlation test. The 3-year overall survival (OS and disease-free survival (DFS were calculated in relation to the two markers. 94 (63.5% of 148 were mTOR high expression, and PTEN high expression was detected in 46 (31.1% of the 148 patients with ESCC. The Pearson correlation coefficient revealed a significant negative correlation in two proteins (correlation coefficient = −0.189, P<0.005. The 3-year OS and DFS time in the mTOR-high group was 23.9 and 18.4 months, respectively, and the time in the mTOR-low group was 33.9 months and 31.4 months, respectively. The difference of survival rate between the two groups remained statistically significant. mTOR-low or PTEN-high patients had better 3-year rates of OS and DFS than mTOR-high or PTEN-low group (P<0.001 by the log-rank test. This study also found that mTOR was an independence prognostic factor by multivariate analysis.

  12. Reciprocal positive regulation between TRPV6 and NUMB in PTEN-deficient prostate cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung-Young; Hong, Chansik; Wie, Jinhong [Department of Physiology, Seoul National University College of Medicine, Seoul 110-799 (Korea, Republic of); Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 110-799 (Korea, Republic of); Kim, Euiyong [Department of Physiology, College of Medicine, Inje University, Busan 614-735 (Korea, Republic of); Kim, Byung Joo [Division of Longevity and Biofunctional Medicine, Pusan National University School of Korean Medicine, Yangsan 626-870 (Korea, Republic of); Ha, Kotdaji [Department of Physiology, Seoul National University College of Medicine, Seoul 110-799 (Korea, Republic of); Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 110-799 (Korea, Republic of); Cho, Nam-Hyuk; Kim, In-Gyu [Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 110-799 (Korea, Republic of); Jeon, Ju-Hong [Department of Physiology, Seoul National University College of Medicine, Seoul 110-799 (Korea, Republic of); Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 110-799 (Korea, Republic of); So, Insuk, E-mail: insuk@snu.ac.kr [Department of Physiology, Seoul National University College of Medicine, Seoul 110-799 (Korea, Republic of); Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 110-799 (Korea, Republic of)

    2014-04-25

    Highlights: • TRPV6 interacts with tumor suppressor proteins. • Numb has a selective effect on TRPV6, depending on the prostate cancer cell line. • PTEN is a novel regulator of TRPV6–Numb complex. - Abstract: Calcium acts as a second messenger and plays a crucial role in signaling pathways involved in cell proliferation. Recently, calcium channels related to calcium influx into the cytosol of epithelial cells have attracted attention as a cancer therapy target. Of these calcium channels, TRPV6 is overexpressed in prostate cancer and is considered an important molecule in the process of metastasis. However, its exact role and mechanism is unclear. NUMB, well-known tumor suppressor gene, is a novel interacting partner of TRPV6. We show that NUMB and TRPV6 have a reciprocal positive regulatory relationship in PC-3 cells. We repeated this experiment in two other prostate cancer cell lines, DU145 and LNCaP. Interestingly, there were no significant changes in TRPV6 expression following NUMB knockdown in DU145. We revealed that the presence or absence of PTEN was the cause of NUMB–TRPV6 function. Loss of PTEN caused a positive correlation of TRPV6–NUMB expression. Collectively, we determined that PTEN is a novel interacting partner of TRPV6 and NUMB. These results demonstrated a novel relationship of NUMB–TRPV6 in prostate cancer cells, and show that PTEN is a novel regulator of this complex.

  13. Role of Inositol Poly-Phosphatases and Their Targets in T Cell Biology

    Directory of Open Access Journals (Sweden)

    Neetu eSrivastava

    2013-09-01

    Full Text Available T lymphocytes play a critical role in host defense in all anatomical sites including mucosal surfaces. This not only includes the effector arm of the immune system, but also regulation of immune responses in order to prevent autoimmunity. Genetic targeting of PI3K isoforms suggests that generation of PI(3,4,5P3 by PI3K plays a critical role in promoting effector T cell responses. Consequently, the 5’- and 3’-inositol poly-phosphatases SHIP1, SHIP2 and PTEN capable of targeting PI(3,4,5P3 are potential genetic determinants of T cell effector functions in vivo. In addition, the 5’-inositol poly phosphatases SHIP1 and 2 can shunt PI(3,4,5P3 to the rare but potent signaling phosphoinositide species PI(3,4P2 and thus these SHIP1/2, and the INPP4A/B enzymes that deplete PI(3,4P2 may have precise roles in T cell biology to amplify or inhibit effectors of PI3K signaling that are selectively recruited to and activated by PI(3,4P2. Here we summarize recent genetic and chemical evidence that indicates the inositol poly-phosphatases have important roles in both the effector and regulatory functions of the T cell compartment. In addition, we will discuss future genetic studies that might be undertaken to further elaborate the role of these enzymes in T cell biology as well as potential pharmaceutical manipulation of these enzymes for therapeutic purposes in disease settings where T cell function is a key in vivo target.

  14. PTEN status is a crucial determinant of the functional outcome of combined MEK and mTOR inhibition in cancer

    Science.gov (United States)

    Milella, Michele; Falcone, Italia; Conciatori, Fabiana; Matteoni, Silvia; Sacconi, Andrea; De Luca, Teresa; Bazzichetto, Chiara; Corbo, Vincenzo; Simbolo, Michele; Sperduti, Isabella; Benfante, Antonina; Del Curatolo, Anais; Cesta Incani, Ursula; Malusa, Federico; Eramo, Adriana; Sette, Giovanni; Scarpa, Aldo; Konopleva, Marina; Andreeff, Michael; McCubrey, James Andrew; Blandino, Giovanni; Todaro, Matilde; Stassi, Giorgio; De Maria, Ruggero; Cognetti, Francesco; Del Bufalo, Donatella; Ciuffreda, Ludovica

    2017-01-01

    Combined MAPK/PI3K pathway inhibition represents an attractive, albeit toxic, therapeutic strategy in oncology. Since PTEN lies at the intersection of these two pathways, we investigated whether PTEN status determines the functional response to combined pathway inhibition. PTEN (gene, mRNA, and protein) status was extensively characterized in a panel of cancer cell lines and combined MEK/mTOR inhibition displayed highly synergistic pharmacologic interactions almost exclusively in PTEN-loss models. Genetic manipulation of PTEN status confirmed a mechanistic role for PTEN in determining the functional outcome of combined pathway blockade. Proteomic analysis showed greater phosphoproteomic profile modification(s) in response to combined MEK/mTOR inhibition in PTEN-loss contexts and identified JAK1/STAT3 activation as a potential mediator of synergistic interactions. Overall, our results show that PTEN-loss is a crucial determinant of synergistic interactions between MAPK and PI3K pathway inhibitors, potentially exploitable for the selection of cancer patients at the highest chance of benefit from combined therapeutic strategies. PMID:28220839

  15. PTEN/PIK3CA genes are frequently mutated in spontaneous and medroxyprogesterone acetate-accelerated 7,12-dimethylbenz(a)anthracene-induced mammary tumours of tree shrews.

    Science.gov (United States)

    Xia, Hou-Jun; He, Bao-Li; Wang, Chun-Yan; Zhang, Hai-Lin; Ge, Guang-Zhe; Zhang, Yuan-Xu; Lv, Long-Bao; Jiao, Jian-Lin; Chen, Ceshi

    2014-12-01

    Tree shrew has increasingly become an attractive experimental animal model for human diseases, particularly for breast cancer due to spontaneous breast tumours and their close relationship to primates and by extension to humans. However, neither normal mammary glands nor breast tumours have been well characterised in the Chinese tree shrew (Tupaia belangeri chinensis). In this study, normal mammary glands from four different developmental stages and 18 spontaneous breast tumours were analysed. Haematoxylin and eosin (H&E) staining and immunohistochemistry (IHC) showed that normal mammary gland morphology and structures of tree shrews were quite similar to those found in humans. Spontaneous breast tumours of tree shrews were identified as being intraductal papilloma, papillary carcinoma, and invasive ductal carcinoma with or without lung metastasis. To further analyse breast cancer tumours among tree shrews, 40 3-4 month-old female tree shrews were orally administrated 20 mg 7,12-dimethylbenz(a)anthracene (DMBA) or peanut oil thrice, and then, 15 of these DMBA administrated tree shrews were implanted with medroxyprogesterone acetate (MPA) pellets. DMBA was shown to induce breast tumours (12%) while the addition of MPA increased the tumour incidence (50%). Of these, three induced breast tumours were intraductal papillary carcinomas and one was invasive ductal carcinoma (IDC). The PTEN/PIK3CA (phosphatase and tensin homologue/phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha), but not TP53 and GATA3, genes are frequently mutated in breast tumours, and the PTEN/PIK3CA gene mutation status correlated with the expression of pAKT in tree shrew breast tumours. These results suggest that tree shrews may be a promising animal model for a subset of human breast cancers with PTEN/PIK3CA gene mutations.

  16. Allosteric Activation of the Phosphoinositide Phosphatase Sac1 by Anionic Phospholipids

    Science.gov (United States)

    2012-01-01

    Sac family phosphoinositide phosphatases comprise an evolutionarily conserved family of enzymes in eukaryotes. Our recently determined crystal structure of the Sac phosphatase domain of yeast Sac1, the founding member of the Sac family proteins, revealed a unique conformation of the catalytic P-loop and a large positively charged groove at the catalytic site. We now report a unique mechanism for the regulation of its phosphatase activity. Sac1 is an allosteric enzyme that can be activated by its product phosphatidylinositol or anionic phospholipid phosphatidylserine. The activation of Sac1 may involve conformational changes of the catalytic P-loop induced by direct binding with the regulatory anionic phospholipids in the large cationic catalytic groove. These findings highlight the fact that lipid composition of the substrate membrane plays an important role in the control of Sac1 function. PMID:22452743

  17. Loss of PTEN is not associated with poor survival in newly diagnosed glioblastoma patients of the temozolomide era.

    Directory of Open Access Journals (Sweden)

    Christine Carico

    Full Text Available INTRODUCTION: Pre-temozolomide studies demonstrated that loss of the tumor suppressor gene PTEN held independent prognostic significance in GBM patients. We investigated whether loss of PTEN predicted shorter survival in the temozolomide era. The role of PTEN in the PI3K/Akt pathway is also reviewed. METHODS: Patients with histologically proven newly diagnosed GBM were identified from a retrospective database between 2007 and 2010. Cox proportional hazards analysis was used to calculate the independent effects of PTEN expression, age, extent of resection, Karnofsky performance scale (KPS, and treatment on overall survival. RESULTS: Sixty-five percent of patients were men with median age of 63 years, and 70% had KPS≥80. Most patients (81% received standard treatment (temozolomide with concurrent radiation. A total of 72 (47% patients had retained PTEN expression. Median overall survival (OS was 19.1 months (95% CI: 15.0-22.5. Median survival of 20.0 months (95% CI: 15.0-25.5 and 18.2 months (95% CI: 13.0-25.7 was observed in PTEN retained and PTEN loss patients, respectively (p = .71. PTEN loss patients were also found to have amplifications of EGFR gene more frequently than patients with retained PTEN (70.8% vs. 47.8%, p = .01. Multivariate analysis showed that older age (HR 1.64, CI: 1.02-2.63, p = .04, low KPS (HR 3.57, CI: 2.20-5.79, p<.0001, and lack of standard treatment (HR 3.98, CI: 2.38-6.65, p<.0001 yielded worse survival. PTEN loss was not prognostic of overall survival (HR 1.31, CI: 0.85-2.03, p = .22. CONCLUSIONS: Loss of expression of PTEN does not confer poor overall survival in the temozolomide era. These findings imply a complex and non-linear molecular relationship between PTEN, its regulators and effectors in the tumorigenesis of glioblastoma. Additionally, there is evidence that temozolomide may be more effective in eradicating GBM cancer cells with PTEN loss and hence, level the outcomes between the PTEN

  18. Effect of liraglutide and PTEN on rats pancreatic islet cell apoptosis induced by high fat diet%Liraglutide及PTEN在高脂饮食诱导的大鼠胰岛细胞凋亡中的作用

    Institute of Scientific and Technical Information of China (English)

    刘涛; 张静; 邢影; 叶晓莉; 杨文娟; 薛玲; 曹宏伟; 彭红艳; 姬秋和

    2011-01-01

    目的 观察高脂饮食的SD大鼠胰腺第10号染色体同源丢失性磷酸酶-张力蛋白基因( PTEN)表达量的变化,以及liraglutide对胰岛细胞凋亡的作用.方法 20只雄性SD大鼠随机分为3组:正常饮食(ND)组(n=6)、高脂饮食(HFD)组(n=6)和高脂饮食并给予liraglutide( HL)组(n=8).ND组给予正常饮食,HFD组和HL组给予高脂饮食持续20周后行OGTT试验.随后ND组和HFD组给予生理盐水0.2 mg/kg,HL组给予liraglutide 0.2 mg/kg,早晚各1次,持续4周,给药终点再次行OG-TT试验,评估β细胞功能.应用实时定量PCR检测各组大鼠胰腺PTEN mRNA相对表达量,TUNEL染色观察大鼠胰岛细胞凋亡的变化.结果 与ND组相比,HFD组和HL组大鼠体重增加(P<0.05),血TG和TC升高(P<0.01),OGTT中胰岛素曲线下面积(AUCIns)增大(P<0.05或P<0.01),且胰腺PTEN mRNA表达量增多(P<0.05).与HFD组相比,HL组体重、进食量和血TC下降(P<0.05或P<0.01),OGTT中60 min和120 min时胰岛素和血糖降低(P<0.01),胰岛细胞凋亡减少,β细胞功能得到一定改善,但胰腺PTEN mRNA表达量的差异无统计学意义(P>0.05).结论 高脂饮食时SD大鼠胰腺PTEN mRNA表达增加,liraglutide对高脂饮食大鼠胰腺PTEN mRNA表达没有影响,但可能通过Akt信号通路减少其胰岛细胞凋亡.%Objective To investigate the expression of phosphatase and tensin homologue (PTEN) deleted on chromosome ten in pancreas of high fat diet rats and the effect of liraglutide on pancreatic islet cell apoptosis. Method Twenty male SD rats were divided into three groups at random: normal diet (ND,n=6), high fat diet (HFD,n=6) and high fat diet with liraglutide(HL,n=8). They were given corresponding food for 20 weeks respectively, followed by an OGTT. Then, the three groups were subjected to subcutaneous administration of saline, saline and liraglutide respectively, 0. 2 mg/kg, twice a day(08:00 and 20:00) for 4 weeks. Amount of food intake was recorded every day

  19. The tumor suppressor PTEN and the PDK1 kinase regulate formation of the columnar neural epithelium.

    Science.gov (United States)

    Grego-Bessa, Joaquim; Bloomekatz, Joshua; Castel, Pau; Omelchenko, Tatiana; Baselga, José; Anderson, Kathryn V

    2016-01-26

    Epithelial morphogenesis and stability are essential for normal development and organ homeostasis. The mouse neural plate is a cuboidal epithelium that remodels into a columnar pseudostratified epithelium over the course of 24 hr. Here we show that the transition to a columnar epithelium fails in mutant embryos that lack the tumor suppressor PTEN, although proliferation, patterning and apical-basal polarity markers are normal in the mutants. The Pten phenotype is mimicked by constitutive activation of PI3 kinase and is rescued by the removal of PDK1 (PDPK1), but does not depend on the downstream kinases AKT and mTORC1. High resolution imaging shows that PTEN is required for stabilization of planar cell packing in the neural plate and for the formation of stable apical-basal microtubule arrays. The data suggest that appropriate levels of membrane-associated PDPK1 are required for stabilization of apical junctions, which promotes cell elongation, during epithelial morphogenesis.

  20. Preclinical Remodeling of Human Prostate Cancer through the PTEN/AKT Pathway

    Directory of Open Access Journals (Sweden)

    Marco A. De Velasco

    2012-01-01

    Full Text Available Knowledge gained from the identification of genetic and epigenetic alterations that contribute to the progression of prostate cancer in humans is now being implemented in the development of functionally relevant translational models. GEM (genetically modified mouse models are being developed to incorporate the same molecular defects associated with human prostate cancer. Haploinsufficiency is common in prostate cancer and homozygous loss of PTEN is strongly correlated with advanced disease. In this paper, we discuss the evolution of the PTEN knockout mouse and the cooperation between PTEN and other genetic alterations in tumor development and progression. Additionally, we will outline key points that make these models key players in the development of personalized medicine, as potential tools for target and biomarker development and validation as well as models for drug discovery.

  1. Association of genetic polymorphisms in PTEN and additional interaction with alcohol consumption and smoking on colorectal cancer in Chinese population.

    Science.gov (United States)

    Han, Mingyang; Wu, Gang; Sun, Peichun; Nie, Jiewei; Zhang, Jiancheng; Li, Yuanyuan

    2015-01-01

    To investigate the association of phosphatase and tensin homologue deleted on chromosome ten (PTEN) gene rs3830675, and additional interaction with drinking and smoking on colorectal cancer (CRC), based on a hospital based Chinese case-control study. A total of 850 subjects (413 males and 437 females) were studied, including 422 colorectal cancer cases and 428 controls. Rs3830675 was selected for genotyping in the case-control study. Logistic regression model was used to examine the association between rs3830675 and colorectal cancer, and additional interaction with alcohol consumption and smoking. The frequencies for rs3830675 (-) alleles was higher in cases than that in controls, (-) allele of rs3830675 was 24.4% in controls and 29.4% in CRC subjects (p=0.005). Logistic analysis showed that the carriers of (-) allele of rs3830675 revealed increased CRC risk than those with (+/+) genotype, adjusted OR (95% CI) was 1.35(1.12-1.98). We found a significant interaction between alcohol consumption and rs3830675, drinkers with (-/-) or (-/+) of rs3830675 genotype have highest colorectal cancer risk, compared to never drinking subjects with (+/+) genotype, OR (95% CI) was 2.57 (1.66-3.33), after covariates adjustment. In addition, we also found that smokers with (-/-) or (-/+) of rs3830675 genotype have highest colorectal cancer risk, compared to never smokers with (+/+) genotype, OR (95% CI) was 3.01 (1.58-6.05). The (-) allele of rs3830675 was positively with colorectal cancer risk. There was a significant role of interaction of rs3830675 with alcohol consumption and smoking on colorectal cancer.

  2. Loss of PTEN Is Associated with Aggressive Behavior in ERG-Positive Prostate Cancer

    Science.gov (United States)

    Leinonen, Katri A.; Saramäki, Outi R.; Furusato, Bungo; Kimura, Takahiro; Takahashi, Hiroyuki; Egawa, Shin; Suzuki, Hiroyoshi; Keiger, Kerri; Hahm, Sung Ho; Isaacs, William B.; Tolonen, Teemu T.; Stenman, Ulf-Håkan; Tammela, Teuvo L.J.; Nykter, Matti; Bova, G. Steven; Visakorpi, Tapio

    2014-01-01

    Background The associations of ERG overexpression with clinical behavior and molecular pathways of prostate cancer are incompletely known. We assessed the association of ERG expression with AR, PTEN, SPINK1, Ki-67, and EZH2 expression levels, deletion, and mutations of chromosomal region 3p14 and TP53, and clinicopathologic variables. Methods The material consisted of 326 prostatectomies, 166 needle biopsies from men treated primarily with endocrine therapy, 177 transurethral resections of castration-resistant prostate cancers (CRPC), and 114 CRPC metastases obtained from 32 men. Immunohistochemistry, FISH, and sequencing was used for the measurements. Results ERG expression was found in about 45% of all patient cohorts. In a multivariate analysis, ERG expression showed independent value of favorable prognosis (P = 0.019). ERG positivity was significantly associated with loss of PTEN expression in prostatectomy (P = 0.0348), and locally recurrent CRPCs (P = 0.0042). Loss of PTEN expression was associated (P = 0.0085) with shorter progression-free survival in ERG-positive, but not in negative cases. When metastases in each subject were compared, consistent ERG, PTEN, and AR expression as well as TP53 mutations were found in a majority of subjects. Conclusions A similar frequency of ERG positivity from early to late stage of the disease suggests lack of selection of ERG expression during disease progression. The prognostic significance of PTEN loss solely in ERG-positive cases indicates interaction of these pathways. The finding of consistent genetic alterations in different metastases suggests that the major genetic alterations take place in the primary tumor. Impact Interaction of PTEN and ERG pathways warrants further studies. PMID:24083995

  3. Oncogenic microRNA-4534 regulates PTEN pathway in prostate cancer.

    Science.gov (United States)

    Nip, Hannah; Dar, Altaf A; Saini, Sharanjot; Colden, Melissa; Varahram, Shahryari; Chowdhary, Harshika; Yamamura, Soichiro; Mitsui, Yozo; Tanaka, Yuichiro; Kato, Taku; Hashimoto, Yutaka; Shiina, Marisa; Kulkarni, Priyanka; Dasgupta, Pritha; Imai-Sumida, Mitsuho; Tabatabai, Z Laura; Greene, Kirsten; Deng, Guoren; Dahiya, Rajvir; Majid, Shahana

    2016-10-18

    Prostate carcinogenesis involves alterations in several signaling pathways, the most prominent being the PI3K/AKT pathway. This pathway is constitutively active and drives prostate cancer (PCa) progression to advanced metastatic disease. PTEN, a critical tumor and metastasis suppressor gene negatively regulates cell survival, proliferation, migration and angiogenesis via the PI3K/Akt pathway. PTEN is mutated, downregulated/dysfunctional in many cancers and its dysregulation correlates with poor prognosis in PCa. Here, we demonstrate that microRNA-4534 (miR-4534) is overexpressed in PCa and show that miR-4534 is hypermethylated in normal tissues and cell lines compared to PCa tissues/cells. miR-4534 exerts its oncogenic effects partly by downregulating the tumor suppressor PTEN gene. Knockdown of miR-4534 impaired cell proliferation, migration/invasion and induced G0/G1 cell cycle arrest and apoptosis in PCa. Suppression of miR-4534 and its effects on tumor growth was confirmed in a xenograft mouse model. We performed parallel experiments in non-cancer RWPE1 cells by overexpessing miR-4534 followed by functional assays. Overexpression of miR-4534 induced pro-cancerous characteristics in this non-cancer cell line. Statistical analyses revealed that miR-4534 has potential to independently distinguish malignant from normal tissues and positively correlated with poor overall and PSA recurrence free survival. Taken together, our results show that depletion of miR-4534 in PCa induces a tumor suppressor phenotype partly through induction of PTEN. These results have important implications for identifying and defining the role of new PTEN regulators such as microRNAs in prostate tumorigenesis. Understanding aberrantly overexpressed miR-4534 and its downregulation of PTEN will provide mechanistic insight and therapeutic targets for PCa therapy.

  4. Brown Seaweed Fucoidan Inhibits Cancer Progression by Dual Regulation of mir-29c/ADAM12 and miR-17-5p/PTEN Axes in Human Breast Cancer Cells

    Science.gov (United States)

    Wu, Szu-Yuan; Yan, Ming-De; Wu, Alexander T.H.; Yuan, Kevin Sheng-Po; Liu, Shing Hwa

    2016-01-01

    In this study, we observed that brown seaweed fucoidan inhibited human breast cancer progression by upregulating microRNA (miR)-29c and downregulating miR-17-5p, thereby suppressing their target genes, a disintegrin and metalloproteinase 12 (ADAM12) and phosphatase and tensin homolog (PTEN), respectively. Moreover, fucoidan reduced the luciferase activity of 3'-untranslated region reporter; treatment of cells with the miR-29c mimic or miR-17-5p inhibitor also produced similar results. These effects of fucoidan inhibited the epithelial-mesenchymal transition in breast cancer cells, as evidenced by an increase in E-cadherin and a drop in N-cadherin, and inhibited breast cancer cell survival, as evidenced by the activation of the phosphoinositide 3-kinase/Akt pathway. Taken together, these findings demonstrate that fucoidan inhibits breast cancer progression by regulating the miR-29c/ADAM12 and miR-17-5p/PTEN axes. Fucoidan is a potential chemopreventive/chemotherapeutic agent for breast cancer. PMID:27994679

  5. Establishment and antitumor effects of dasatinib and PKI-587 in BD-138T, a patient-derived muscle invasive bladder cancer preclinical platform with concomitant EGFR amplification and PTEN deletion

    Science.gov (United States)

    Lim, Joung Eun; Jeong, Da Eun; Song, Hye Jin; Kim, Sudong; Nam, Do-Hyun; Sung, Hyun Hwan; Jeong, Byong Chang; Seo, Seong Il; Jeon, Seong Soo; Lee, Hyun Moo; Choi, Han-Yong; Jeon, Hwang Gyun

    2016-01-01

    Muscle-invasive bladder cancer (MIBC) consists of a heterogeneous group of tumors with a high rate of metastasis and mortality. To facilitate the in-depth investigation and validation of tailored strategies for MIBC treatment, we have developed an integrated approach using advanced high-throughput drug screening and a clinically relevant patient-derived preclinical platform. We isolated patient-derived tumor cells (PDCs) from a rare MIBC case (BD-138T) that harbors concomitant epidermal growth factor receptor (EGFR) amplification and phosphatase and tensin homolog (PTEN) deletion. High-throughput in vitro drug screening demonstrated that dasatinib, a SRC inhibitor, and PKI-587, a dual PI3K/mTOR inhibitor, exhibited targeted anti-proliferative and pro-apoptotic effects against BD-138T PDCs. Using established patient-derived xenograft models that successfully retain the genomic and molecular characteristics of the parental tumor, we confirmed that these anti-tumor responses occurred through the inhibition of SRC and PI3K/AKT/mTOR signaling pathways. Taken together, these experimental results demonstrate that dasatinib and PKI-587 might serve as promising anticancer drug candidates for treating MIBC with combined EGFR gene amplification and PTEN deletion. PMID:27438149

  6. mRNA EXPRESSION OF PTEN AND VEGF GENES IN EPITHELIAL OVARIAN CANCER

    Institute of Scientific and Technical Information of China (English)

    陈颖; 赵雨杰; 郑华川; 杨雪飞; 汪桂兰; 辛彦

    2003-01-01

    Objective: To investigate the mRNA expression of PTEN and vascular endothelial growth factor (VEGF) genes in ovarian cancer. Methods:We examined mRNA expression of PTEN and VEGF165 in normal ovary (n=5), ovarian cyst (n=5), ovarian borderline tumor (n=9), epithelial ovarian cancer (n=60) and ovarian cancer cell line (CAOV-3) by RT-PCR. Their expressions were compared with clinicopathological features of ovarian cancer. The relationship between their expressions was concerned in all ovarian samples as well. Results:mRNA expression level of PTEN gene was significantly lower in ovarian borderline tumor or ovarian cancer than that in normal ovary or ovarian cyst(P<0.05). It was negatively correlated with clinicopathological staging(P<0.05),whereas positively with histological differentiation (P<0.05). mRNA expression level of PTEN gene was significantly lower in ovarian endometrioid cancer than ovarian serous or mucinous cancer(P<0.05). mRNA expression level of VEGF165 gene was significantly higher in ovarian cancer than that in normal ovary or ovarian cyst(P<0.05). It was positively correlated with clinicopathological staging(P<0.05), whereas negatively with histological differentiation (P<0.05). mRNA expression level of VEGF165 gene was significantly higher in ovarian serous cancer than in other ovarian epithelial cancers (P<0.05). mRNA expression of VEGF165 gene was inversely correlated with mRNA expression level of PTEN gene. Conclusion:Down-regulated expression of PTEN and up-regulated expression of VEGF were considered as two important events in tumorigenesis of ovarian cancer and could be used as molecular markers to indicate the pathobiological behaviors of ovarian cancer. Decreased PTEN expression and increased VEGF expression were closely associated with tumorigenesis and pathobiological behaviors of ovarian endometrioid and serous cancer respectively. Reduced expression of PTEN gene might be involved in carcinogenesis and progression of ovarian cancer by

  7. Protein phosphatases 1 and 2A promote Raf-1 activation by regulating 14-3-3 interactions.

    Science.gov (United States)

    Jaumot, M; Hancock, J F

    2001-07-01

    Raf-1 activation is a complex process which involves plasma membrane recruitment, phosphorylation, protein-protein and lipid-protein interactions. We now show that PP1 and PP2A serine-threonine phosphatases also have a positive role in Ras dependent Raf-1 activation. General serine-threonine phosphatase inhibitors such sodium fluoride, or ss-glycerophosphate and sodium pyrophosphate, or specific PP1 and PP2A inhibitors including microcystin-LR, protein phosphatase 2A inhibitor I(1) or protein phosphatase inhibitor 2 all abrogate H-Ras and K-Ras dependent Raf-1 activation in vitro. A critical Raf-1 target residue for PP1 and PP2A is S259. Serine phosphatase inhibitors block the dephosphorylation of S259, which accompanies Raf-1 activation, and Ras dependent activation of mutant Raf259A is relatively resistant to serine phosphatase inhibitors. Sucrose gradient analysis demonstrates that serine phosphatase inhibition increases the total amount of 14-3-3 and Raf-1 associated with the plasma membrane and significantly alters the distribution of 14-3-3 and Raf-1 across different plasma membrane microdomains. These observations suggest that dephosphorylation of S259 is a critical early step in Ras dependent Raf-1 activation which facilitates 14-3-3 displacement. Inhibition of PP1 and PP2A therefore causes plasma membrane accumulation of Raf-1/14-3-3 complexes which cannot be activated.

  8. Multisystemic functions of alkaline phosphatases.

    Science.gov (United States)

    Buchet, René; Millán, José Luis; Magne, David

    2013-01-01

    Human and mouse alkaline phosphatases (AP) are encoded by a multigene family expressed ubiquitously in multiple tissues. Gene knockout (KO) findings have helped define some of the precise exocytic functions of individual isozymes in bone, teeth, the central nervous system, and in the gut. For instance, deficiency in tissue-nonspecific alkaline phosphatase (TNAP) in mice (Alpl (-/-) mice) and humans leads to hypophosphatasia (HPP), an inborn error of metabolism characterized by epileptic seizures in the most severe cases, caused by abnormal metabolism of pyridoxal-5'-phosphate (the predominant form of vitamin B6) and by hypomineralization of the skeleton and teeth featuring rickets and early loss of teeth in children or osteomalacia and dental problems in adults caused by accumulation of inorganic pyrophosphate (PPi). Enzyme replacement therapy with mineral-targeting TNAP prevented all the manifestations of HPP in mice, and clinical trials with this protein therapeutic are showing promising results in rescuing life-threatening HPP in infants. Conversely, TNAP induction in the vasculature during generalized arterial calcification of infancy (GACI), type II diabetes, obesity, and aging can cause medial vascular calcification. TNAP inhibitors, discussed extensively in this book, are in development to prevent pathological arterial calcification. The brush border enzyme intestinal alkaline phosphatase (IAP) plays an important role in fatty acid (FA) absorption, in protecting gut barrier function, and in determining the composition of the gut microbiota via its ability to dephosphorylate lipopolysaccharide (LPS). Knockout mice (Akp3 (-/-)) deficient in duodenal-specific IAP (dIAP) become obese, and develop hyperlipidemia and hepatic steatosis when fed a high-fat diet (HFD). These changes are accompanied by upregulation in the jejunal-ileal expression of the Akp6 IAP isozyme (global IAP, or gIAP) and concomitant upregulation of FAT/CD36, a phosphorylated fatty acid

  9. 参附注射液对糖尿病大鼠心肌缺血再灌注时PTEN和P13 K表达的影响%Effects of Shenfu injectio on expression of PTEN and PI3K during myocardial ischemia-reperfusion in diabetic rats

    Institute of Scientific and Technical Information of China (English)

    夏中元; 江梦; 肖业达; 孟庆涛

    2009-01-01

    Objective To investigate the effect of Shenfu injectio (SFI) on the expression of phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and phosphatidylinositol 3-kinase (PI3K) during myocardial ischemia-reperfusion (IR) in diabetic rats.Methods Thirty adult male diabetic SD rats weighing 220-280 g were used in this study. Diabetes mellitus was induced with intraperitoneal streptozotocin 60 mg/kg and confirmed by fasting blood glucose > 16.7 mmol/L. The animals were randomly divided into 3 groups ( n = 10 each): group I sham operation (group S); group II IR and group Ⅲ SFI. Myocardial IR was produced by occlusion of left anterior descending branch (LAD) of coronary artery for 30 min followed by 120 min reperfusion in group IR and SFI. LAD was exposed but not occluded in group S.SFI was infused iv at 10 ml·kg-1 ·h-1 before opening the thoracic cavity and at 3ml·kg-1·h-1 after opening the thoracic cavity in group SFI until the end of operation. Equal volume of Lactated Ringer's solution and hydroxyethyl starch was infused instead of SFI in group S and IR. The rats were killed and hearts removed at 120 min of reperfusion for microscopic examination and determination of cardiomyocyte apoptosis (by TUNEL)and expression of PTEN and PDK (by immunohistochemical method). PTEN/PI3K ratio, myocardial infarct size of left ventricle and apoptosis index were calculated.Correlation between apoptosis index and PTEN/PI3K ratio was analyzed. Results Myocardial infarct size and apoptosis index were significantly increased, while expression of PTEN and PI3K was up-regulated in group IR and SFI as compared with group S ( P < 0.05 or 0.01) . PTEN/PI3K ratio was significantly decreased in group SFI as compared with group S (P< 0.05). Myocardial infarct size and apoptosis index were significantly decreased, PTEN expression was down-regulated, PI3K expression was up-regulated and PTEN/PI3K ratio was significantly decreased in group SFI as compared with group IR( P < 0

  10. PTEN loss is associated with worse outcome in HER2-amplified breast cancer patients but is not associated with trastuzumab resistance

    Science.gov (United States)

    Stern, Howard M.; Gardner, Humphrey; Burzykowski, Tomasz; Elatre, Wafaa; O’Brien, Carol; Lackner, Mark R.; Pestano, Gary A.; Santiago, Angela; Villalobos, Ivonne; Eiermann, Wolfgang; Pienkowski, Tadeusz; Martin, Miguel; Robert, Nicholas; Crown, John; Nuciforo, Paolo; Bee, Valerie; Mackey, John; Slamon, Dennis J.; Press, Michael F.

    2015-01-01

    Purpose To investigate the clinical relevance of PTEN in HER2-amplified and HER2-non-amplified disease. Experimental Design We assessed PTEN status in two large adjuvant breast cancer trials (BCIRG-006 and BCIRG-005) using a PTEN IHC assay that was previously validated in a panel of 33 breast cancer cell lines and prostate cancer tissues with known PTEN gene deletion. Results In the HER2-positive patient population, absence of tumor cell PTEN staining occurred at a rate of 5.4% and was independent of ER/PR status. In contrast, 15.9% of HER2-negative patients exhibited absence of PTEN staining with the highest frequency seen in triple negative breast cancer (TNBC) subgroup versus ER/PR-positive patients (35.1% vs. 10.9%). Complete absence of PTEN staining in tumor cells was associated with poor clinical outcome in HER2-positive disease. Those patients whose cancers demonstrated absent PTEN staining had a significant decrease in disease-free survival (DFS) and overall survival (OS) compared to patients with tumors exhibiting any PTEN staining patterns (low, moderate or high). Trastuzumab appeared to provide clinical benefit even for patients lacking PTEN staining. In the HER2-negative population there were no statistically significant differences in clinical outcome based on PTEN status. Conclusions This study is the largest to date examining PTEN status in breast cancer and the data suggest that the rate and significance of PTEN status differ between HER2-positive and HER2-negative disease. Furthermore, the data clearly suggest that HER2-positive patients with PTEN loss still benefit from trastuzumab. PMID:25649019

  11. Alterations in PTEN and PIK3CA in colorectal cancers in the EPIC Norfolk study: associations with clinicopathological and dietary factors

    Directory of Open Access Journals (Sweden)

    Mitrou Panagiota N

    2011-04-01

    Full Text Available Abstract Background The PTEN tumour suppressor gene and PIK3CA proto-oncogene encode proteins which contribute to regulation and propagation of signal transduction through the PI3K/AKT signalling pathway. This study investigates the prevalence of loss of PTEN expression and mutations in both PTEN and PIK3CA in colorectal cancers (CRC and their associations with tumour clinicopathological features, lifestyle factors and dietary consumptions. Methods 186 adenocarcinomas and 16 adenomas from the EPIC Norfolk study were tested for PTEN and PIK3CA mutations by DNA sequencing and PTEN expression changes by immunohistochemistry. Dietary and lifestyle data were collected prospectively using seven day food diaries and lifestyle questionnaires. Results Mutations in exons 7 and 8 of PTEN were observed in 2.2% of CRC and PTEN loss of expression was identified in 34.9% CRC. Negative PTEN expression was associated with lower blood low-density lipoprotein concentrations (p = 0.05. PIK3CA mutations were observed in 7% of cancers and were more frequent in CRCs in females (p = 0.04. Analysis of dietary intakes demonstrated no link between PTEN expression status and any specific dietary factor. PTEN expression negative, proximal CRC were of more advanced Dukes' stage (p = 0.02 and poor differentiation (p PIK3CA mutations and loss of PTEN expression demonstrated that these two events were independent (p = 0.55. Conclusion These data demonstrated the frequent occurrence (34.9% of PTEN loss of expression in colorectal cancers, for which gene mutations do not appear to be the main cause. Furthermore, dietary factors are not associated with loss of PTEN expression. PTEN expression negative CRC were not homogenous, as proximal cancers were associated with a more advanced Dukes' stage and poor differentiation, whereas distal cancers were associated with earlier Dukes' stage.

  12. Intestinal alkaline phosphatase prevents metabolic syndrome in mice.

    Science.gov (United States)

    Kaliannan, Kanakaraju; Hamarneh, Sulaiman R; Economopoulos, Konstantinos P; Nasrin Alam, Sayeda; Moaven, Omeed; Patel, Palak; Malo, Nondita S; Ray, Madhury; Abtahi, Seyed M; Muhammad, Nur; Raychowdhury, Atri; Teshager, Abeba; Mohamed, Mussa M Rafat; Moss, Angela K; Ahmed, Rizwan; Hakimian, Shahrad; Narisawa, Sonoko; Millán, José Luis; Hohmann, Elizabeth; Warren, H Shaw; Bhan, Atul K; Malo, Madhu S; Hodin, Richard A

    2013-04-23

    Metabolic syndrome comprises a cluster of related disorders that includes obesity, glucose intolerance, insulin resistance, dyslipidemia, and fatty liver. Recently, gut-derived chronic endotoxemia has been identified as a primary mediator for triggering the low-grade inflammation responsible for the development of metabolic syndrome. In the present study we examined the role of the small intestinal brush-border enzyme, intestinal alkaline phosphatase (IAP), in preventing a high-fat-diet-induced metabolic syndrome in mice. We found that both endogenous and orally supplemented IAP inhibits absorption of endotoxin (lipopolysaccharides) that occurs with dietary fat, and oral IAP supplementation prevents as well as reverses metabolic syndrome. Furthermore, IAP supplementation improves the lipid profile in mice fed a standard, low-fat chow diet. These results point to a potentially unique therapy against metabolic syndrome in at-risk humans.

  13. Inhibition of Notch pathway arrests PTEN-deficient advanced prostate cancer by triggering p27-driven cellular senescence

    Science.gov (United States)

    Revandkar, Ajinkya; Perciato, Maria Luna; Toso, Alberto; Alajati, Abdullah; Chen, Jingjing; Gerber, Hermeto; Dimitrov, Mitko; Rinaldi, Andrea; Delaleu, Nicolas; Pasquini, Emiliano; D'Antuono, Rocco; Pinton, Sandra; Losa, Marco; Gnetti, Letizia; Arribas, Alberto; Fraering, Patrick; Bertoni, Francesco; Nepveu, Alain; Alimonti, Andrea

    2016-01-01

    Activation of NOTCH signalling is associated with advanced prostate cancer and treatment resistance in prostate cancer patients. However, the mechanism that drives NOTCH activation in prostate cancer remains still elusive. Moreover, preclinical evidence of the therapeutic efficacy of NOTCH inhibitors in prostate cancer is lacking. Here, we provide evidence that PTEN loss in prostate tumours upregulates the expression of ADAM17, thereby activating NOTCH signalling. Using prostate conditional inactivation of both Pten and Notch1 along with preclinical trials carried out in Pten-null prostate conditional mouse models, we demonstrate that Pten-deficient prostate tumours are addicted to the NOTCH signalling. Importantly, we find that pharmacological inhibition of γ-secretase promotes growth arrest in both Pten-null and Pten/Trp53-null prostate tumours by triggering cellular senescence. Altogether, our findings describe a novel pro-tumorigenic network that links PTEN loss to ADAM17 and NOTCH signalling, thus providing the rational for the use of γ-secretase inhibitors in advanced prostate cancer patients. PMID:27941799

  14. Mechanistic Rationale to Target PTEN-Deficient Tumor Cells with Inhibitors of the DNA Damage Response Kinase ATM.

    Science.gov (United States)

    McCabe, Nuala; Hanna, Conor; Walker, Steven M; Gonda, David; Li, Jie; Wikstrom, Katarina; Savage, Kienan I; Butterworth, Karl T; Chen, Clark; Harkin, D Paul; Prise, Kevin M; Kennedy, Richard D

    2015-06-01

    Ataxia telangiectasia mutated (ATM) is an important signaling molecule in the DNA damage response (DDR). ATM loss of function can produce a synthetic lethal phenotype in combination with tumor-associated mutations in FA/BRCA pathway components. In this study, we took an siRNA screening strategy to identify other tumor suppressors that, when inhibited, similarly sensitized cells to ATM inhibition. In this manner, we determined that PTEN and ATM were synthetically lethal when jointly inhibited. PTEN-deficient cells exhibited elevated levels of reactive oxygen species, increased endogenous DNA damage, and constitutive ATM activation. ATM inhibition caused catastrophic DNA damage, mitotic cell cycle arrest, and apoptosis specifically in PTEN-deficient cells in comparison with wild-type cells. Antioxidants abrogated the increase in DNA damage and ATM activation in PTEN-deficient cells, suggesting a requirement for oxidative DNA damage in the mechanism of cell death. Lastly, the ATM inhibitor KU-60019 was specifically toxic to PTEN mutant cancer cells in tumor xenografts and reversible by reintroduction of wild-type PTEN. Together, our results offer a mechanistic rationale for clinical evaluation of ATM inhibitors in PTEN-deficient tumors.

  15. Expression of phosphatase and tensin homolog deleted on chromosome ten in liver of athymic mice with hepatocellular carcinoma and the effect of Fuzheng Jiedu Decoction

    Institute of Scientific and Technical Information of China (English)

    Li-Rong Yin; Ze-Xiong Chen; Shi-Jun Zhang; Bao-Guo Sun; Yong-Dong Liu; Hong-Zhong Huang

    2008-01-01

    AIM:To explore the expression of phosphatase and tensin homolog deleted on chromosome ten (PTEN) in liver of athymic mice with hepatocellular carcinoma (HCC) and the effect of Fuzheng Jiedu Decoction (FJD). METHODS: Forty eight male BALB/c athymic mice models were built by Bel-7402 with an indirect method. After 24 h of postoperation, the 48 athymic mice were distributed randomly into 4 groups: A, B, C, D, each group had 12 athymic mice. Group A were were treated by intragastric administration with FT207 (Tegafur) for 4 wk. Group B, C and D were treated by intragastric administration with FJD (complex prescription of Chinese crude drug) that had been delegated into 3 kinds of density as the low, middle, and high for 4 wk. At last,athymic mice were put to death, live time, volume of tumors, exponent of tumors and the tumor metastasis in livers were observed; and PTEN was detected in hepatic tissue, latero-cancer tissue and cancer tissue by immunohistochemistry.RESULTS: Four weeks later, the total survival rate in treatment group (A + B + C) was 50% and higher than the control group (0%) treated by FT207, (P 0.05). Tumor metastasis in livers of the treatment group was less than the controls (Fisher's Exact Test, P = 0.021). Thee result of immunohistochemistry showed that the intensity of PTEN in latero-cancer tissue was the highest, and then the hepatic tissue, the lowest was cancer tissue (Kruskal- Wallis test, .67, P = 0.000). It also showed that the intensity of PTEN in treatment groups (A, B, C) was higher than the control group (D) (F = 5.90,P = 0.002 in hepatic tissue and F = 15.99, P = 0.000 in latero-cancer tissue and .08, P = 0.000 in cancer tissue), and group B is the highest in the treatment groups (P 0.05).CONCLUSION: FJD can prolong the survival time and decrease tumor metastasis in livers of these experimental mice. Mechanisms of FJD healing HCC may partially be explained by enhancing the expression of PTEN in liver.

  16. Variable phenotypes associated with 10q23 microdeletions involving the PTEN and BMPR1A genes.

    NARCIS (Netherlands)

    Menko, F.H.; Kneepkens, C.M.; Leeuw, N. de; Peeters, E.A.; Maldergem, L Van; Kamsteeg, E.J.; Davidson, R.; Rozendaal, L.; Lasham, C.A.; Peeters-Scholte, C.M.; Jansweijer, M.C.E.; Hilhorst-Hofstee, Y.; Gille, J.J.P.; Heins, Y.M.; Nieuwint, A.W.; Sistermans, E.A.

    2008-01-01

    Infantile juvenile polyposis is a rare disease with severe gastrointestinal symptoms and a grave clinical course. Recently, 10q23 microdeletions involving the PTEN and BMPR1A genes were found in four patients with infantile juvenile polyposis. It was hypothesized that a combined and synergistic effe

  17. PTEN Gene and Prostate Cancer%PTEN基因与前列腺癌

    Institute of Scientific and Technical Information of China (English)

    孙健玮(综述); 王剑松(审校)

    2013-01-01

    The deletion of tumor suppressor gene PTEN's expression was familiar in many tumors, including prostate cancer. The guide would be given in the diagnosis, therapy and prognosis of prostate cancer by studying about PTEN's tumor suppression mechanism and relation with expression deletion. This review makes an overview focusing on the recent progress of PTEN's structure, function, expression deletion, and the correlation between PTEN and prostate cancer.%抑癌基因PTEN的表达缺失多见于包括前列腺癌在内的多种散发性肿瘤,对其抑癌机制以及表达缺失所导致的肿瘤发生发展机理的研究,将为前列腺癌的诊断、治疗以及预后判断提供指导。就PTEN基因的结构、作用机制、表达缺失及其与前列腺癌发病相关的研究进展作一综述。

  18. PTEN Mediates the Antioxidant Effect of Resveratrol at Nutritionally Relevant Concentrations

    Directory of Open Access Journals (Sweden)

    Marta Inglés

    2014-01-01

    Full Text Available Introduction. Antioxidant properties of resveratrol have been intensively studied for the last years, both in vivo and in vitro. Its bioavailability after an oral dose is very low and therefore it is very important to make sure that plasma concentrations of free resveratrol are sufficient enough to be active as antioxidant. Aims. In the present study, using nutritionally relevant concentrations of resveratrol, we aim to confirm its antioxidant capacity on reducing peroxide levels and look for the molecular pathway involved in this antioxidant effect. Methods. We used mammary gland tumor cells (MCF-7, which were pretreated with different concentrations of resveratrol for 48 h, and/or a PTEN inhibitor (bpV: bipy. Hydrogen peroxide levels were determined by fluorimetry, PTEN levels and Akt phosphorylation by Western Blotting, and mRNA expression of antioxidant genes by real-time reverse transcriptase-polymerase chain reaction (RT-PCR. Results. Resveratrol treatment for 48 h lowered peroxide levels in MCF-7, even at low nutritional concentrations (1 nM. This effect was mediated by the activation of PTEN/Akt pathway, which resulted in an upregulation of catalase and MnSOD mRNA levels. Conclusion. Resveratrol acts as an antioxidant at nutritionally relevant concentrations by inducing the expression of antioxidant enzymes, through a mechanism involving PTEN/Akt signaling pathway.

  19. Propylthiouracil, independent of its antithyroid effect, promotes vascular smooth muscle cells differentiation via PTEN induction.

    Science.gov (United States)

    Chen, Wei-Jan; Pang, Jong-Hwei S; Lin, Kwang-Huei; Lee, Dany-Young; Hsu, Lung-An; Kuo, Chi-Tai

    2010-01-01

    Propylthiouracil (PTU), independent of its antithyroid effect, is recently found to have an antiatherosclerotic effect. The aim of this study is to determine the impact of PTU on phenotypic modulation of vascular smooth muscle cells (VSMCs), as phenotypic modulation may contribute to the growth of atherosclerotic lesions and neointimal formation after arterial injury. Propylthiouracil reduced neointimal formation in balloon-injured rat carotid arteries. In vitro, PTU may convert VSMCs from a serum-induced dedifferentiation state to a differentiated state, as indicated by a spindle-shaped morphology and an increase in the expression of SMC differentiation marker contractile proteins, including calponin and smooth muscle (SM)-myosin heavy chain (SM-MHC). Transient transfection studies in VSMCs demonstrated that PTU induced the activity of SMC marker genes (calponin and SM-MHC) promoters, indicating that PTU up-regulates these genes expression predominantly at the transcriptional level. Furthermore, PTU enhanced the expression of PTEN and inhibition of PTEN by siRNA knockdown blocked PTU-induced activation of contractile proteins expression and promoter activity. In the rat carotid injury model, PTU reversed the down-regulation of contractile proteins and up-regulated PTEN in the neointima induced by balloon injury. Propylthiouracil promotes VSMC differentiation, at lest in part, via induction of the PTEN-mediated pathway. These findings suggest a possible mechanism by which PTU may contribute to its beneficial effects on atherogenesis and neointimal formation after arterial injury.

  20. Methodological aspects of the molecular and histological study of prostate cancer: focus on PTEN.

    Science.gov (United States)

    Ugalde-Olano, Aitziber; Egia, Ainara; Fernández-Ruiz, Sonia; Loizaga-Iriarte, Ana; Zuñiga-García, Patricia; Garcia, Stephane; Royo, Félix; Lacasa-Viscasillas, Isabel; Castro, Erika; Cortazar, Ana R; Zabala-Letona, Amaia; Martín-Martín, Natalia; Arruabarrena-Aristorena, Amaia; Torrano-Moya, Verónica; Valcárcel-Jiménez, Lorea; Sánchez-Mosquera, Pilar; Caro-Maldonado, Alfredo; González-Tampan, Jorge; Cachi-Fuentes, Guido; Bilbao, Elena; Montero, Rocío; Fernández, Sara; Arrieta, Edurne; Zorroza, Kerman; Castillo-Martín, Mireia; Serra, Violeta; Salazar, Eider; Macías-Cámara, Nuria; Tabernero, Jose; Baselga, Jose; Cordón-Cardo, Carlos; Aransay, Ana M; Villar, Amaia Del; Iovanna, Juan L; Falcón-Pérez, Juan M; Unda, Miguel; Bilbao, Roberto; Carracedo, Arkaitz

    2015-05-01

    Prostate cancer is among the most frequent cancers in men, and despite its high rate of cure, the high number of cases results in an elevated mortality worldwide. Importantly, prostate cancer incidence is dramatically increasing in western societies in the past decades, suggesting that this type of tumor is exquisitely sensitive to lifestyle changes. Prostate cancer frequently exhibits alterations in the PTEN gene (inactivating mutations or gene deletions) or at the protein level (reduced protein expression or altered sub-cellular compartmentalization). The relevance of PTEN in this type of cancer is further supported by the fact that the sole deletion of PTEN in the murine prostate epithelium recapitulates many of the features of the human disease. In order to study the molecular alterations in prostate cancer, we need to overcome the methodological challenges that this tissue imposes. In this review we present protocols and methods, using PTEN as proof of concept, to study different molecular characteristics of prostate cancer. Copyright © 2015. Published by Elsevier Inc.

  1. High-calorie diet exacerbates prostate neoplasia in mice with haploinsufficiency of Pten tumor suppressor gene

    Directory of Open Access Journals (Sweden)

    Jehnan Liu

    2015-03-01

    Conclusion: High-calorie diet promotes prostate cancer progression in the genetically susceptible Pten haploinsufficient mouse while preserving insulin sensitivity. This appears to be partly due to increased inflammatory response to high-caloric intake in addition to increased ability of insulin to promote lipogenesis.

  2. Welcoming Treat: Astrocyte-Derived Exosomes Induce PTEN Suppression to Foster Brain Metastasis.

    Science.gov (United States)

    Alečković, Maša; Kang, Yibin

    2015-11-09

    Metastasis to distant organs depends on pathological crosstalk between tumor cells and various tissue-specific stromal components. Zhang and colleagues recently demonstrated that astrocyte-derived exosomal miR-19a reversibly downregulated PTEN expression in cancer cells, thereby increasing their CCL2 secretion and recruitment of myeloid cell to promote brain metastasis.

  3. Correlation between Protein Expression of PTEN in Human Pancreatic Cancer and the Proliferation, Infiltration, Metastasis and Prognosis

    Institute of Scientific and Technical Information of China (English)

    TAO Jing; XIONG Jiongxin; LI Tao; YANG Zhiyong; LI Xiaohui; LI Kai; WU Heshui; WANG Chunyou

    2006-01-01

    In order to investigate the correlation between protein expression of PTEN and the proliferation, infiltration, metastasis and prognosis in pancreatic cancer, immunohistochemical SP method was used to examine the protein expression of PTEN, PCNA, MVD, MMP-2, MMP-9 and TUNEL method to detect the levels of apoptosis of pancreatic cells in 41 pancreatic head cancers from regional pancreatectomy (RP) and 10 normal pancreatic tissues. The results showed that among 41 cases of pancreatic cancers, the positive staining of PTNE (39.02 %) was significantly weaker than that in normal pancreatic tissues (P<0.05). The levels of PCNA labeling index (LI), apoptotic index(AI), microvessel density (MVD), MMP-2 LI and MMP-9 LI were decreased gradually with the increase of the expression intensity of PTEN, and there was a significant difference in the above parameters among the patients having different expression levels of PTEN (P<0.01 or P<0.05). There was a negative correlation between the expression of PTEN and PCNA LI, MVD, MMP-2 LI,MMP-9 LI, and a positive correlation between AI and the expression of PTEN. The expression intensity of PTEN was correlated with the postoperative survival of the patients with pancreatic cancer(x2=22.3400, P<0.0001, RR=2.030). It was suggested that the expression levels of PTEN protein were closely related with proliferation, infiltration and metastasis in human pancreatic cancer, and the expression of PTEN protein was one of the prognostic factors for pancreatic cancer following RP.

  4. Association of alkaline phosphatase phenotypes with arthritides

    Directory of Open Access Journals (Sweden)

    Padmini A

    2004-01-01

    Full Text Available Arthritides, a symmetrical polyarticular disease of the bone are a heterogenous group of disorders in which hereditary and environmental factors in combination with an altered immune response appear to play a causative and pathogenic role in its occurrence. Alkaline phosphatase (ALP is an enzyme found in all tissues, with particularly high concentrations of ALP observed in the liver, bile ducts, placenta, and bone.Alkaline phosphatase is an orthophosphoric monoester phosphohydrolase catalyzing the hydrolysis of organic esters at alkaline pH, indicating that alkaline phosphatase is involved in fundamental biological processes.1 The present study envisages on identifying the specific electromorphic association of alkaline phosphatase with arthritides. Phenotyping of serum samples was carried out by PAGE (Polyacrylamide gel electrophoresis following Davies (19642 protocol on 41 juvenile arthritis, 150 rheumatoid arthritis and 100 osteo arthritis apart from, 25 normal children and 100 adult healthy subjects. Phenotyping of alkaline phosphatase revealed an increase in preponderance of p+ and p++ phenotypes in juvenile, rheumatoid and osteo arthritic patients. However a significant association of these phenotypes was observed only with rheumatoid arthritis condition (c2:17.46. Similarly, a significant increase of p+ phenotypes in female rheumatoid arthritis patients was observed (c2:14.973, suggesting that the decrease in p° (tissue non specific synthesis/secretion of alkaline phosphatase could be associated with decreased mineralization and ossification process in arthritis condition.

  5. PTEN loss represses glioblastoma tumor initiating cell differentiation via inactivation of Lgl1.

    Science.gov (United States)

    Gont, Alexander; Hanson, Jennifer E L; Lavictoire, Sylvie J; Parolin, Doris A; Daneshmand, Manijeh; Restall, Ian J; Soucie, Mathieu; Nicholas, Garth; Woulfe, John; Kassam, Amin; Da Silva, Vasco F; Lorimer, Ian A J

    2013-08-01

    Glioblastoma multiforme is an aggressive and incurable type of brain tumor. A subset of undifferentiated glioblastoma cells, known as glioblastoma tumor initiating cells (GTICs), has an essential role in the malignancy of this disease and also appears to mediate resistance to radiation therapy and chemotherapy. GTICs retain the ability to differentiate into cells with reduced malignant potential, but the signaling pathways controlling differentiation are not fully understood at this time. PTEN loss is a very common in glioblastoma multiforme and leads to aberrant activation of the phosphoinositide 3-kinase pathway. Increased signalling through this pathway leads to activation of multiple protein kinases, including atypical protein kinase C. In Drosophila, active atypical protein kinase C has been shown to promote the self-renewal of neuroblasts, inhibiting their differentiation along a neuronal lineage. This effect is mediated by atypical protein kinase c-mediated phosphorylation and inactivation of Lgl, a protein that was first characterized as a tumour suppressor in Drosophila. The effects of the atypical protein kinase C/Lgl pathway on the differentiation status of GTICs, and its potential link to PTEN loss, have not been assessed previously. Here we show that PTEN loss leads to the phosphorylation and inactivation of Lgl by atypical protein kinase C in glioblastoma cells. Re-expression of PTEN in GTICs promoted their differentiation along a neuronal lineage. This effect was also seen when atypical protein kinase C was knocked down using RNA interference, and when a non-phosphorylatable, constitutively active form of Lgl was expressed in GTICs. Thus PTEN loss, acting via atypical protein kinase C activation and Lgl inactivation, helps to maintain GTICs in an undifferentiated state.

  6. Second Malignant Neoplasms in Patients With Cowden Syndrome With Underlying Germline PTEN Mutations

    Science.gov (United States)

    Ngeow, Joanne; Stanuch, Kim; Mester, Jessica L.; Barnholtz-Sloan, Jill S.; Eng, Charis

    2014-01-01

    Purpose Patients with Cowden syndrome (CS) with underlying germline PTEN mutations are at increased risk of breast, thyroid, endometrial, and renal cancers. To our knowledge, risk of subsequent cancers in these patients has not been previously explored or quantified. Patients and Methods We conducted a 7-year multicenter prospective study (2005 to 2012) of patients with CS or CS-like disease, all of whom underwent comprehensive PTEN mutational analysis. Second malignant neoplasms (SMNs) were ascertained by medical records and confirmed by pathology reports. Standardized incidence ratios (SIRs) for all SMNs combined and for breast, thyroid, endometrial, and renal cancers were calculated. Results Of the 2,912 adult patients included in our analysis, 2,024 had an invasive cancer history. Germline pathogenic PTEN mutations (PTEN mutation positive) were identified in 114 patients (5.6%). Of these 114 patients, 46 (40%) had an SMN. Median age of SMN diagnosis was 50 years (range, 21 to 71 years). Median interval between primary cancer and SMN was 5 years (range, breast cancer, 11 (22%) had a subsequent new primary breast cancer and 10-year second breast cancer cumulative risk of 29% (95% CI, 15.3 to 43.7). Risk of SMNs compared with that of the general population was significantly elevated for all cancers (SIR, 7.74; 95% CI, 5.84 to 10.07), specifically for breast (SIR, 8.92; 95% CI, 5.85 to 13.07), thyroid (SIR, 5.83; 95% CI, 3.01 to 10.18), and endometrial SMNs (SIR, 14.08.07; 95% CI, 7.10 to 27.21). Conclusion Patients with CS with germline PTEN mutations are at higher risk for SMNs compared with the general population. Prophylactic mastectomy should be considered on an individual basis given the significant risk of subsequent breast cancer. PMID:24778394

  7. The genetic basis of Cowden's syndrome: three novel mutations in PTEN/MMAC1/TEP1.

    Science.gov (United States)

    Tsou, H C; Ping, X L; Xie, X X; Gruener, A C; Zhang, H; Nini, R; Swisshelm, K; Sybert, V; Diamond, T M; Sutphen, R; Peacocke, M

    1998-04-01

    Cowden's syndrome (CS) is an autosomal dominant disorder associated with an increased risk of developing benign and malignant tumors in a variety of tissues, including the skin, thyroid, breast and brain. Women with CS are felt to have an increased risk of developing breast cancer, and virtually all women with CS develop bilateral fibrocystic disease of the breast. Recently, a series of germline mutations have been identified from CS families in a gene known as PTEN/MMAC1/TEP1. In this study, we used heteroduplex analysis and direct sequencing analysis and identified three novel germline mutations in the PTEN/MMAC1/TEP1 coding sequence from unrelated individuals with CS. We report a de novo transition (T-->C) at nucleotide 335 in exon 5. This missense mutation resulted in a leucine to proline (CTA to CCA) change at codon 112. We also describe a novel splice site mutation (801+2T-->G) in intron 7 that caused exon skipping in PTEN/MMAC1/TEP1 mRNA. The third mutation we report is a missense mutation, consisting of a transition (T-->C) at nucleotide 202 in exon 3, resulting in a tyrosine to histidine (TAC to CAC) change at codon 68. Finally, we also detected a rare polymorphism in exon 7 of the PTEN/MMAC1/TEP1 coding sequence. These data confirm the observation that mutations of the PTEN/MMAC1/TEP1 coding sequence are responsible for at least some cases of CS, and further define the spectrum of mutations in this autosomal dominant disorder.

  8. The effect of silibinin in enhancing toxicity of temozolomide and etoposide in p53 and PTEN-mutated resistant glioma cell lines.

    Science.gov (United States)

    Elhag, Rashid; Mazzio, Elizabeth A; Soliman, Karam F A

    2015-03-01

    Glioblastoma multiforme (GBM) is an intractable brain tumor, associated with poor prognosis and low survival rate. Combination therapy such as surgery, radiotherapy and temozolomide is considered standard in overcoming this aggressive cancer, despite poor prognosis. There is a need to identify potential agents, which may augment the chemotherapeutic effects of standard drugs such as temozolomide. In this project, we evaluated the effects of silibinin, a natural plant component of milk thistle seeds, to potentiate toxic effects of chemotherapy drugs such as temozolomide, etoposide and irinotecan on LN229, U87 and A172 (P53 and phosphatase and tensin homolog (PTEN) -tumor suppressor-mutated) glioma cell lines. Data from this work suggest that silibinin was effective in potentiating the cytotoxic efficacy of temozolomide in LN229, U87 and A172 cells. While silibinin reduced survivin protein expression only in LN229 cells, its ability to potentiate cytotoxicity of chemo therapy drugs occurred irrespective of survivin protein levels. The data also demonstrated that silibinin potentiated the effect of etoposide and but not irinotecan in LN229 cells. Future research will be required to evaluate the in vivo efficacy of silibinin to delineate its mechanism of action and its ability to cross the blood-brain barrier.

  9. Survivin与PTEN在喉部鳞状细胞癌变中的表达关系初探%Analysis on expression of Survivin and PTEN in vocal cords polyps,papilloma of larynx and laryngeal squamous cell carcinoma

    Institute of Scientific and Technical Information of China (English)

    郭强中; 李云英

    2012-01-01

    Through exploring the differentiation on positive expressing rates between oncogene Survivin and tumor-suppresser gene PTEN(phosphatase and tensin homolog deleteted on chromosome Ten) on vocal cord polyps(VCP), adult type laryngeal papilloma (ALP) , and Laryngeal Squamous Cell Carcinoma (LSCC) , to reveal the mechanism in canceration of human laryngeal squamous cells, from benign proliferative lesion, benign tumor to malignant tumor in larynx. Method:After picking out 18 cases of VCP, 10 cases of ALP, and 18 cases of LSCC for immunohistochemical process of Survivin and PTEN with two continuous section preparations, the differentiations of positive expression rates of Survivin and PTEN in the same human laryngeal squamous cells areas among three diseases were compared. Result:The positive expressing rates of Survivin and PTEN in VCP were obviously more lower than in ALP and LSCC(P0.05). The positive expressing rates of Survivin were always higher than PTEN in VCP, ALP and LSCC evi-dently(P<0. 05). Conclusion:PTEN, expressing for competition purpose, shows a subordinative relationship with Survivin. Although they have opposite functions in determine whether the canceration of laryngeal squamous cells take place or not, Survivin is always playing the leading role and making predominant impact on development of benign proliferative lesion, benign and malignant tumor in larynx.%目的:研究声带息肉、成人型喉乳头状瘤和喉鳞状细胞癌3种疾病中Survivin和PTEN的表达特点,以了解喉鳞状细胞从增生到癌变的可能机制.方法:选取符合临床与病理诊断的声带息肉患者18例、成人型喉乳头状瘤患者10例和喉鳞状细胞癌患者18例,将每个患者的病理蜡块标本各连续切片2张,分别进行Survivin和PTEN免疫组织化学检测.比较致癌基因Survivin和抑癌基因PTEN在这3种疾病同一区域鳞状上皮细胞中的表达差异.结果:声带息肉的Survivin和PTEN阳性率均显著低于喉乳头

  10. Prophylactic treatment with alkaline phosphatase in cardiac surgery induces endogenous alkaline phosphatase release

    NARCIS (Netherlands)

    Kats, Suzanne; Brands, Ruud; Hamad, Mohamed A. Soliman; Seinen, Willem; Schamhorst, Volkher; Wulkan, Raymond W.; Schoenberger, Jacques P.; van Oeveren, Wim

    2012-01-01

    Introduction: Laboratory and clinical data have implicated endotoxin as an important factor in the inflammatory response to cardiopulmonary bypass. We assessed the effects of the administration of bovine intestinal alkaline phosphatase (bIAP), an endotoxin detoxifier, on alkaline phosphatase levels

  11. Lipid somersaults

    DEFF Research Database (Denmark)

    Günther-Pomorski, Thomas; Menon, Anant K.

    2016-01-01

    Membrane lipids diffuse rapidly in the plane of the membrane but their ability to flip spontaneously across a membrane bilayer is hampered by a significant energy barrier. Thus spontaneous flip-flop of polar lipids across membranes is very slow, even though it must occur rapidly to support divers...

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

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Alok R. [UCSD Department of Pediatrics, Moores UCSD Cancer Center, University of California School of Medicine, San Diego, CA 92093 (United States); Peirce, Susan K. [Department of Pediatrics, Emory University School of Medicine, Atlanta, GA (United States); Joshi, Shweta [UCSD Department of Pediatrics, Moores UCSD Cancer Center, University of California School of Medicine, San Diego, CA 92093 (United States); Durden, Donald L., E-mail: ddurden@ucsd.edu [UCSD Department of Pediatrics, Moores UCSD Cancer Center, University of California School of Medicine, San Diego, CA 92093 (United States); Division of Pediatric Hematology-Oncology, UCSD Rady Children' s Hospital, La Jolla, CA (United States)

    2014-09-10

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

  13. Isolation and characterization of lipid-associated and neurosecretory polypeptides

    OpenAIRE

    Stark, Margareta

    2000-01-01

    Lipid-interacting proteins play important roles in all living organisms. This thesis focuses on isolation and characterization of an enzyme in the triacylglycerol biosynthesis (phosphatidic acid phosphatase, PAP), hydrophobic polypeptides in bile, and polypeptides in cerebrospinal fluid. These fields constitute methodological challenges and mean development of suitable tools in between lipid and protein biochemistry. Two methods used to measure PAP activity were compared. I...

  14. [Phosphatase and tensin homolog deleted on chromosome ten/phosphatidyl Inositol 3-kinase/vascular endothelial growth factor signaling pathway changes in the rabbit Kawasaki disease model].

    Science.gov (United States)

    Niu, L; Fu, M Y; Tian, J; He, X H; Zhang, H N; Wang, Q W; Wang, Y; Li, C L; Wang, Z Z; An, X J

    2016-03-01

    To observe the changes of phosphatase and tensin homolog deleted on chromosome ten(PTEN)/ phosphatidyl Inositol 3-kinase(PI3K)/ vascular endothelial growth factor(VEGF)signaling pathway in a rabbit Kawasaki disease model. Model of Kawasaki disease was established in weanling Japanese big-eared rabbits with 10% bovine serum venous injection (2.5 ml/kg, 2 times, and 2 week's interval) through the ear. Twenty four rabbits were divided into 4 groups: control group (without injection of 10% bovine serum albumin, six rabbits); 1 day group (sacrificed a the second day after the establishment of Kawasaki disease models, six rabbits); 7 day group (sacrificed at the seventh day after establishment of Kawasaki disease model, six rabbits); 30 day group (sacrificed at the thirtieth day after establishment of Kawasaki disease model, six rabbits). Pathological analysis was performed on coronary artery tissue samples. The express of PTEN and PI3K were detected by immunohistochemistry. The levels of VEGF and CK were also examined with ELISA and white blood cells were counted. (1) Coronary artery of model groups was thinner, distorted and had enlarged lumen. (2) PTEN expression in 1 d group, 7 d group and 30 d group were 58.5 ± 12.9, 73.2±9.9 and 109.6 ± 24.4, respectively, significantly higher than in the control group (25.5 ± 6.9, P0.05) and significantly lower than 1 d and 7 d group (both P0.05). (6)White blood cell count were significantly higher in 1 d group, 7 d group and 30 d group than in control group (all PKawasaki disease model and the signaling pathway might be involved in this model.

  15. BCR-mediated apoptosis associated with negative selection of immature B cells is selectively dependent on Pten

    Institute of Scientific and Technical Information of China (English)

    Shuhua Cheng; Constance Yu Hsia; Biao Feng; Me-Ling Liou; Xiaoying Fang; Pier Paolo Pandolfi; Hsiou-Chi Liou

    2009-01-01

    The molecular basis of B cell receptor (BCR)-induced apoptosis during the negative selection of immature B cells is largely unknown. We use transitional immature B cells that are highly susceptible to BCR-induced apoptosis to show that Pten is selectively required for BCR-mediated initiation of the mitochondrial death pathway. Specifically,deleting Pten, but not other pro-apoptotic molecules, abrogates BCR-elicited apoptosis and improves viability in wild-type immature B cells. We further identify a physiologically and significantly higher intracellular Pten level in immature B cells, as compared to mature B cells, which is responsible for low AKT activity and the propensity towards death in immature B cells. Restoration of AKT activity using a constitutive form of AKT or reduction of Pten to a level comparable with that seen in mature B cells rescues immature B cells from BCR-induced apoptosis. Thus,we provide evidence that Pten is an essential mediator of BCR-induced cell death, and that differential regulation of intracellular Pten levels determines whether BCR ligation promotes cell death or survival. Our findings provide a valuable insight into the mechanisms underlying negative selection and clonal deletion of immature B cells.

  16. Phosphorylation of the actin binding protein Drebrin at S647 is regulated by neuronal activity and PTEN.

    Directory of Open Access Journals (Sweden)

    Patricia Kreis

    Full Text Available Defects in actin dynamics affect activity-dependent modulation of synaptic transmission and neuronal plasticity, and can cause cognitive impairment. A salient candidate actin-binding protein linking synaptic dysfunction to cognitive deficits is Drebrin (DBN. However, the specific mode of how DBN is regulated at the central synapse is largely unknown. In this study we identify and characterize the interaction of the PTEN tumor suppressor with DBN. Our results demonstrate that PTEN binds DBN and that this interaction results in the dephosphorylation of a site present in the DBN C-terminus--serine 647. PTEN and pS647-DBN segregate into distinct and complimentary compartments in neurons, supporting the idea that PTEN negatively regulates DBN phosphorylation at this site. We further demonstrate that neuronal activity increases phosphorylation of DBN at S647 in hippocampal neurons in vitro and in ex vivo hippocampus slices exhibiting seizure activity, potentially by inducing rapid dissociation of the PTEN:DBN complex. Our results identify a novel mechanism by which PTEN is required to maintain DBN phosphorylation at dynamic range and signifies an unusual regulation of an actin-binding protein linked to cognitive decline and degenerative conditions at the CNS synapse.

  17. Potential role of voltage-sensing phosphatases in regulation of cell structure through the production of PI(3,4)P2.

    Science.gov (United States)

    Yamaguchi, Shinji; Kurokawa, Tatsuki; Taira, Ikuko; Aoki, Naoya; Sakata, Souhei; Okamura, Yasushi; Homma, Koichi J

    2014-04-01

    Voltage-sensing phosphatase, VSP, consists of the transmembrane domain, operating as the voltage sensor, and the cytoplasmic domain with phosphoinositide-phosphatase activities. The voltage sensor tightly couples with the cytoplasmic phosphatase and membrane depolarization induces dephosphorylation of several species of phosphoinositides. VSP gene is conserved from urochordate to human. There are some diversities among VSP ortholog proteins; range of voltage of voltage sensor motions as well as substrate selectivity. In contrast with recent understandings of biophysical mechanisms of VSPs, little is known about its physiological roles. Here we report that chick ortholog of VSP (designated as Gg-VSP) induces morphological feature of cell process outgrowths with round cell body in DF-1 fibroblasts upon its forced expression. Expression of the voltage sensor mutant, Gg-VSPR153Q with shifted voltage dependence to a lower voltage led to more frequent changes of cell morphology than the wild-type protein. Coexpression of PTEN that dephosphorylates PI(3,4)P2 suppressed this effect by Gg-VSP, indicating that the increase of PI(3,4)P2 leads to changes of cell shape. In addition, visualization of PI(3,4)P2 with the fluorescent protein fused with the TAPP1-derived pleckstrin homology (PH) domain suggested that Gg-VSP influenced the distribution of PI(3,4)P2 . These findings raise a possibility that one of the VSP's functions could be to regulate cell morphology through voltage-sensitive tuning of phosphoinositide profile.

  18. Defining Starch Binding by Glucan Phosphatases

    DEFF Research Database (Denmark)

    Auger, Kyle; Raththagala, Madushi; Wilkens, Casper;

    2015-01-01

    Starch is a vital energy molecule in plants that has a wide variety of uses in industry, such as feedstock for biomaterial processing and biofuel production. Plants employ a three enzyme cyclic process utilizing kinases, amylases, and phosphatases to degrade starch in a diurnal manner. Starch...... is comprised of the branched glucan amylopectin and the more linear glucan amylose. Our lab has determined the first structures of these glucan phosphatases and we have defined their enzymatic action. Despite this progress, we lacked a means to quickly and efficiently quantify starch binding to glucan...... phosphatases. The main objective of this study was to quantify the binding affinity of different enzymes that are involved in this cyclic process. We established a protocol to quickly, reproducibly, and quantitatively measure the binding of the enzymes to glucans utilizing Affinity Gel Electrophoresis (AGE...

  19. Defining Starch Binding by Glucan Phosphatases

    DEFF Research Database (Denmark)

    Auger, Kyle; Raththagala, Madushi; Wilkens, Casper

    2015-01-01

    phosphatases. The main objective of this study was to quantify the binding affinity of different enzymes that are involved in this cyclic process. We established a protocol to quickly, reproducibly, and quantitatively measure the binding of the enzymes to glucans utilizing Affinity Gel Electrophoresis (AGE...... glucan phosphatases showed similar affinities for the short oligosaccharide β-cyclodextrin. We performed structure-guided mutagenesis to define the mechanism of these differences. We found that the carbohydrate binding module (CBM) domain provided a stronger binding affinity compared to surface binding...

  20. A functional network of the tumor suppressors APC, hDlg, and PTEN, that relies on recognition of specific PDZ-domains.

    Science.gov (United States)

    Sotelo, Natalia S; Valiente, Miguel; Gil, Anabel; Pulido, Rafael

    2012-08-01

    APC and PTEN are tumor suppressor proteins that bind through their C-termini to the PDZ domain containing-hDlg scaffolding protein. We have found that co-expression of PTEN and hDlg enhanced the negative regulation of the PI3K/Akt pathway by PTEN, indicating the physiologic importance of these interactions. APC and PTEN share other PDZ domain containing-interacting partners, including the MAGI scaffolding proteins and the MAST family of protein kinases. Mutational analysis revealed that the C-terminal PDZ-binding motifs from APC and PTEN were differentially recognized by distinct PDZ domains. APC bound to the three PDZ domains from hDlg, whereas PTEN mainly bound to PDZ-2/hDlg. This indicates the existence of overlapping, but distinct PDZ-domain recognition patterns by APC and PTEN. Furthermore, a ternary complex formed by APC, PTEN, and hDlg was detected, suggesting that hDlg may serve as a platform to bring in proximity APC and PTEN tumor suppressor activities. In line with this, tumor-related mutations targeting the PDZ-2/hDlg domain diminished its interaction with APC and PTEN. Our results expand the PDZ-domain counterparts for the tumor suppressor APC, show that APC and PTEN share PDZ-domain partners but have individual molecular determinants for specific recognition of PDZ domains, and suggest the participation of the tumor suppressors APC, PTEN, and hDlg in PDZ-domain interaction networks which may be relevant in oncogenesis.

  1. Cooperativity Between Oncogenic PKC Epsilon and Pten Loss in Prostate Cancer Progression

    Science.gov (United States)

    2015-10-01

    initiated studies to dissect the signaling mechanisms that mediate CXCL13 induction. We took advantage of a cellular model that we generated in our...metastatic loop that is mediated by CXCL13. We also hypothesize that PKCε is a CXCL13:CXCR5 effector that contributes to positively amplify this oncogenic...shown). Therefore, it is possible that an autocrine CXCL13:CXCR5 loop mediates effects driven by PKCε overexpression and Pten loss. * * R el at iv

  2. Exploring the Hypersensitivity of PTEN Deleted Prostate Cancer Stem Cells to WEE1 Tyrosine Kinase Inhibitors

    Science.gov (United States)

    2015-12-01

    deletion Inhibitors/drugs ABL1 4% SAC, 2% AML Stomach adenocarcinoma (SAC), Acute myeloid leukemias (AML) Amplifications and missense mutations, Gene fusion...Rassool,F.V. (2013) Targeting abnormal DNA double-strand break repair in tyrosine kinase inhibitor-resistant chronic myeloid leukemias . Oncogene, 32, 1784...with the WEE1 inhibitor, MK1775. In contrast to LNCaP, MK1775 induces a differentiation like phenotype in the PTEN wildtype prostate cancer derived

  3. Loss of heterozygosity on 10q23.3 and mutation of tumor suppressor gene PTEN in gastric cancer and precancerous lesions

    Institute of Scientific and Technical Information of China (English)

    Yi-Ling Li; Zhong Tian; Dong-Ying Wu; Bao-Yu Fu; Yan Xin

    2005-01-01

    AIM: To investigate the loss of heterozygosity (LOH) and mutation of tumor suppressor gene PTEN in gastric cancer and precancerous lesions.METHODS: Thirty cases of normal gastric mucosa, advanced and early stage gastric cancer, intestinal metaplasia, atrophic gastritis, and atypical hyperplasia were analyzed for PTEN LOH and mutations within the entire coding region of PTEN gene by PCR-SSCP denaturing PAGE gel electrophoresis,and PTEN mutation was detected by PCR-SSCP sequencing followed by silver staining.RESULTS: LOH rate found in respectively atrophic gastritis was 10% (3/30), intestinal metaplasia 10% (3/30), atypical hyperpiasia 13.3% (4/30), early stage gastric cancer 20%(6/30), and advanced stage gastric cancer 33.3% (9/30),None of the precancerous lesions and early stage gastric cancer showed PTEN mutations, but 10% (3/30) of the advanced stage gastric cancers, which were all positive for LOH, showed PTEN mutation.CONCLUSION: LOH of PTEN gene appears in precancerous lesions, and PTEN mutations are restricted to advanced gastric cancer, LOH and mutation of PTEN gene are closely related to the infiltration and metastasis of gastric cancer.

  4. Tumor Suppressor Pten Inhibits Nuclear Accumulation of β-Catenin and T Cell/Lymphoid Enhancer Factor 1–Mediated Transcriptional Activation

    Science.gov (United States)

    Persad, Sujata; A.Troussard, Armelle; McPhee, Timothy R.; Mulholland, David J.; Dedhar, Shoukat

    2001-01-01

    β-Catenin is a protein that plays a role in intercellular adhesion as well as in the regulation of gene expression. The latter role of β-catenin is associated with its oncogenic properties due to the loss of expression or inactivation of the tumor suppressor adenomatous polyposis coli (APC) or mutations in β-catenin itself. We now demonstrate that another tumor suppressor, PTEN, is also involved in the regulation of nuclear β-catenin accumulation and T cell factor (TCF) transcriptional activation in an APC-independent manner. We show that nuclear β-catenin expression is constitutively elevated in PTEN null cells and this elevated expression is reduced upon reexpression of PTEN. TCF promoter/luciferase reporter assays and gel mobility shift analysis demonstrate that PTEN also suppresses TCF transcriptional activity. Furthermore, the constitutively elevated expression of cyclin D1, a β-catenin/TCF–regulated gene, is also suppressed upon reexpression of PTEN. Mechanistically, PTEN increases the phosphorylation of β-catenin and enhances its rate of degradation. We define a pathway that involves mainly integrin-linked kinase and glycogen synthase kinase 3 in the PTEN-dependent regulation of β-catenin stability, nuclear β-catenin expression, and transcriptional activity. Our data indicate that β-catenin/TCF–mediated gene transcription is regulated by PTEN, and this may represent a key mechanism by which PTEN suppresses tumor progression. PMID:11402061

  5. Depletion of DNMT3A Suppressed Cell Proliferation and Restored PTEN in Hepatocellular Carcinoma Cell

    Directory of Open Access Journals (Sweden)

    Zhujiang Zhao

    2010-01-01

    Full Text Available Promoter hypermethylation mediated by DNA methyltransferases (DNMTs is the main reason for epigenetic inactivation of tumor suppressor genes (TSGs. Previous studies showed that DNMT1 and DNMT3B play an important role in CpG island methylation in tumorigenesis. Little is known about the role of DNMT3A in this process, especially in hepatocellular carcinoma (HCC. In the present study, increased DNMT3A expression in 3 out of 6 HCC cell lines and 16/25 (64% HCC tissues implied that DNMT3A is involved in hepatocellular carcinogenesis. Depletion of DNMT3A in HCC cell line SMMC-7721 inhibited cell proliferation and decreased the colony formation (about 65%. Microarray data revealed that 153 genes were upregulated in DNMT3A knockdown cells and that almost 71% (109/153 of them contain CpG islands in their 5′ region. 13 of them including PTEN, a crucial tumor suppressor gene in HCC, are genes involved in cell cycle and cell proliferation. Demethylation of PTEN promoter was observed in DNMT3A-depleted cells implying that DNMT3A silenced PTEN via DNA methylation. These results provide insights into the mechanisms of DNMT3A to regulate TSGs by an epigenetic approach in HCC.

  6. Persistently increased intestinal fraction of alkaline phosphatase

    DEFF Research Database (Denmark)

    Nathan, E; Baatrup, G; Berg, H

    1984-01-01

    Persistent elevation of the intestinal fraction of the alkaline phosphatase (API) as an isolated finding has to our knowledge not been reported previously. It was found in a boy followed during a period of 5.5 years. The only symptom was transient periodic fatigue observed at home, but not appare...

  7. Protein-tyrosine phosphatases in zebrafish gastrulation

    NARCIS (Netherlands)

    van Eekelen, M.J.L.

    2011-01-01

    Protein tyrosine phosphorylation plays a key role in relaying external stimuli and signals into the cell towards the appropriate responses. This process is mediated by protein-tyrosine kinases adding a phosphor group to a tyrosine residue and protein-tyrosine phosphatases removing a phosphor group f

  8. Enzyme kinetic characterization of protein tyrosine phosphatases

    DEFF Research Database (Denmark)

    Peters, Günther H.J.; Branner, S.; Møller, K. B.

    2003-01-01

    Protein tyrosine phosphatases (PTPs) play a central role in cellular signaling processes, resulting in an increased interest in modulating the activities of PTPs. We therefore decided to undertake a detailed enzyme kinetic evaluation of various transmembrane and cytosolic PTPs (PTPalpha, PTPbeta...

  9. An integrative genomic and proteomic analysis of PIK3CA, PTEN and AKT mutations in breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Stemke-Hale, Katherine; Gonzalez-Angulo, Ana Maria; Lluch, Ana; Neve, Richard M.; Kuo, Wen-Lin; Davies, Michael; Carey, Mark; Hu, Zhi; Guan, Yinghui; Sahin, Aysegul; Symmans, W. Fraser; Pusztai, Lajos; Nolden, Laura K.; Horlings, Hugo; Berns, Katrien; Hung, Mien-Chie; van de Vijver, Marc J.; Valero, Vicente; Gray, Joe W.; Bernards, Rene; Mills, Gordon B.; Hennessy, Bryan T.

    2008-05-06

    Phosphatidylinositol-3-kinase (PI3K)/AKT pathway aberrations are common in cancer. By applying mass spectroscopy-based sequencing and reverse phase protein arrays to 547 human breast cancers and 41 cell lines, we determined the subtype specificity and signaling effects of PIK3CA, AKT and PTEN mutations, and the effects of PIK3CA mutations on responsiveness to PI3K inhibition in-vitro and on outcome after adjuvant tamoxifen. PIK3CA mutations were more common in hormone receptor positive (33.8%) and HER2-positive (24.6%) than in basal-like tumors (8.3%). AKT1 (1.4%) and PTEN (2.3%) mutations were restricted to hormone receptor-positive cancers with PTEN protein levels also being significantly lower in hormone receptor-positive cancers. Unlike AKT1 mutations, PIK3CA (39%) and PTEN (20%) mutations were more common in cell lines than tumors, suggesting a selection for these but not AKT1 mutations during adaptation to culture. PIK3CA mutations did not have a significant impact on outcome in 166 hormone receptor-positive breast cancer patients after adjuvant tamoxifen. PIK3CA mutations, in comparison with PTEN loss and AKT1 mutations, were associated with significantly less and indeed inconsistent activation of AKT and of downstream PI3K/AKT signaling in tumors and cell lines, and PTEN loss and PIK3CA mutation were frequently concordant, suggesting different contributions to pathophysiology. PTEN loss but not PIK3CA mutations rendered cells sensitive to growth inhibition by the PI3K inhibitor LY294002. Thus, PI3K pathway aberrations likely play a distinct role in the pathogenesis of different breast cancer subtypes. The specific aberration may have implications for the selection of PI3K-targeted therapies in hormone receptor-positive breast cancer.

  10. Inhibitory Effect of Isoflavones on Prostate Cancer Cells and PTEN Gene

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Objective To explore the mechanisms by which genistein and daidzein inhibit the growth of prostate cancer cells. Methods LNCaP and PC-3 cells were exposed to genistein and daidzein and cell viability was determined by MTT assay and cytotoxicity of the drugs by LDH test. Flow cytometry (FCM) was used to assess the cell cycle in LNCaP and PC-3 cells.Reverse transcription-polymerase chain reaction (RT-PCR) was applied to examine the expression of PTEN gene (a tumor suppressor gene), estrogen receptor alpha gene (Erα), estrogen receptor beta gene (Erβ), androgen receptor gene (AR) and vascular endothelial growth factor gene (VEGF). Results The viability of PC-3 and LNCaP cells decreased with increasing concentrations and exposure time of genistein and daidzein. Genistein increased G2/M phase cells in PC-3 cells while decreased S phase cells in LNCaP cells in a dose-dependent manner. Daidzein exerted no influence on the cell cycle of LNCaP and PC-3 cells, but the apoptosis percentage of LNCaP cells was elevated significantly by daidzein. Genistein induced the expression of PTEN gene in PC-3 and LNCaP cells. Daidzein induced the expression of PTEN gene in LNCaP but not in PC-3 cells. The expression of VEGF, Erα and Erβ genes decreased and AR gene was not expressed after incubation with genistein and daidzein in PC-3 cells. In LNCaP cells, the expression of VEGF and AR gene decreased but there was no change in the expression of Erα and Erβ gene after incubation with genistein and daidzein. Conclusion Genistein and daidzein exert a time- and dose-dependent inhibitory effect on PC-3 and LNCaP cells. The down-regulation of ER gene by daidzein influences the growth of PC-3 cells directly. The inhibition of PC-3 cells by genistein and that of LNCaP cells by genistein and daidzein may be via Akt pathway that is repressed by PTEN gene, which subsequently down-regulates the expression of AR and VEGF genes. Our results suggest that the expression of PTEN gene plays a key

  11. [Leucocyte alkaline phosphatase in normal and pathological pregnancy (author's transl)].

    Science.gov (United States)

    Stark, K H; Zaki, I; Sobolewski, K

    1981-01-01

    The activities of leucocyte alkaline phosphatase were determined in 511 patients with normal and pathological pregnancy. Mean values were compared and the enzyme followed up, and the conclusion was drawn that leucocyte alkaline phosphatase was no safe indicator of foetal condition. No direct relationship were found to exist between leucocyte alkaline phosphatase, total oestrogens, HSAP, HLAP, HPL, and oxytocinase.

  12. A single-copy Sleeping Beauty transposon mutagenesis screen identifies new PTEN-cooperating tumor suppressor genes.

    Science.gov (United States)

    de la Rosa, Jorge; Weber, Julia; Friedrich, Mathias Josef; Li, Yilong; Rad, Lena; Ponstingl, Hannes; Liang, Qi; de Quirós, Sandra Bernaldo; Noorani, Imran; Metzakopian, Emmanouil; Strong, Alexander; Li, Meng Amy; Astudillo, Aurora; Fernández-García, María Teresa; Fernández-García, María Soledad; Hoffman, Gary J; Fuente, Rocío; Vassiliou, George S; Rad, Roland; López-Otín, Carlos; Bradley, Allan; Cadiñanos, Juan

    2017-03-20

    The overwhelming number of genetic alterations identified through cancer genome sequencing requires complementary approaches to interpret their significance and interactions. Here we developed a novel whole-body insertional mutagenesis screen in mice, which was designed for the discovery of Pten-cooperating tumor suppressors. Toward this aim, we coupled mobilization of a single-copy inactivating Sleeping Beauty transposon to Pten disruption within the same genome. The analysis of 278 transposition-induced prostate, breast and skin tumors detected tissue-specific and shared data sets of known and candidate genes involved in cancer. We validated ZBTB20, CELF2, PARD3, AKAP13 and WAC, which were identified by our screens in multiple cancer types, as new tumor suppressor genes in prostate cancer. We demonstrated their synergy with PTEN in preventing invasion in vitro and confirmed their clinical relevance. Further characterization of Wac in vivo showed obligate haploinsufficiency for this gene (which encodes an autophagy-regulating factor) in a Pten-deficient context. Our study identified complex PTEN-cooperating tumor suppressor networks in different cancer types, with potential clinical implications.

  13. 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.

  14. C-Myc negatively controls the tumor suppressor PTEN by upregulating miR-26a in glioblastoma multiforme cells

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Pin; Nie, Quanmin; Lan, Jin; Ge, Jianwei [Department of Neurosurgery, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127 (China); Qiu, Yongming, E-mail: qiuzhoub@hotmail.com [Department of Neurosurgery, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127 (China); Shanghai Institute of Head Trauma, Shanghai 200127 (China); Mao, Qing, E-mail: maoq@netease.com [Department of Neurosurgery, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127 (China); Shanghai Institute of Head Trauma, Shanghai 200127 (China)

    2013-11-08

    Highlights: •The c-Myc oncogene directly upregulates miR-26a expression in GBM cells. •ChIP assays demonstrate that c-Myc interacts with the miR-26a promoter. •Luciferase reporter assays show that PTEN is a specific target of miR-26a. •C-Myc–miR-26a suppression of PTEN may regulate the PTEN/AKT pathway. •Overexpression of c-Myc enhances the proliferative capacity of GBM cells. -- Abstract: The c-Myc oncogene is amplified in many tumor types. It is an important regulator of cell proliferation and has been linked to altered miRNA expression, suggesting that c-Myc-regulated miRNAs might contribute to tumor progression. Although miR-26a has been reported to be upregulated in glioblastoma multiforme (GBM), the mechanism has not been established. We have shown that ectopic expression of miR-26a influenced cell proliferation by targeting PTEN, a tumor suppressor gene that is inactivated in many common malignancies, including GBM. Our findings suggest that c-Myc modulates genes associated with oncogenesis in GBM through deregulation of miRNAs via the c-Myc–miR-26a–PTEN signaling pathway. This may be of clinical relevance.

  15. Gene Expression and Correlation of Pten and Fabp4 in Liver, Muscle, and Adipose Tissues of Type 2 Diabetes Rats.

    Science.gov (United States)

    Su, Di; Zhang, Chuan-Ling; Gao, Ying-Chun; Liu, Xiao-Ying; Li, Cai-Ping; Huangfu, Jian; Xiao, Rui

    2015-11-22

    The aim of this work was to study the Fabp4 and Pten gene expression and correlation in the liver, muscle, and adipose tissues of type 2 diabetes mellitus (T2DM) rats. Male Wistar rats (8 weeks old) were randomly divided into 2 groups (n=12/group): a control group fed a normal diet for 8 weeks and an experimental group fed a high-fat, high-sugar diet for 8 weeks and that received 25 mg/kg streptozotocin by intraperitoneal injection to induce T2DM. The random blood glucose, fasting blood glucose, and fasting insulin levels were measured. The expression of Pten and Fabp4 in the liver, muscle, and epididymal adipose tissues was estimated by real-time quantitative PCR. Pearson correlation coefficient analysis was used to investigate the expression correlation between Pten and Fabp4 in T2DM rats. The gene expressions of Pten and Fabp4 in the liver, muscle, and adipose tissues of T2DM rats were all significantly higher than those in the control group (Pmuscles and Fabp4 was highly expressed in muscle and adipose tissues. Furthermore, expressions of Fabp4 and Pten in the muscle and adipose tissues of T2DM rats were positively correlated (Pmuscles of T2DM rats may play an important role in the insulin resistance of T2DM. However, the mechanism by which these 2 genes function in T2DM needs further study.

  16. Systems biology reveals new strategies for personalizing cancer medicine and confirms the role of PTEN in resistance to trastuzumab.

    Science.gov (United States)

    Faratian, Dana; Goltsov, Alexey; Lebedeva, Galina; Sorokin, Anatoly; Moodie, Stuart; Mullen, Peter; Kay, Charlene; Um, In Hwa; Langdon, Simon; Goryanin, Igor; Harrison, David J

    2009-08-15

    Resistance to targeted cancer therapies such as trastuzumab is a frequent clinical problem not solely because of insufficient expression of HER2 receptor but also because of the overriding activation states of cell signaling pathways. Systems biology approaches lend themselves to rapid in silico testing of factors, which may confer resistance to targeted therapies. Inthis study, we aimed to develop a new kinetic model that could be interrogated to predict resistance to receptor tyrosine kinase (RTK) inhibitor therapies and directly test predictions in vitro and in clinical samples. The new mathematical model included RTK inhibitor antibody binding, HER2/HER3 dimerization and inhibition, AKT/mitogen-activated protein kinase cross-talk, and the regulatory properties of PTEN. The model was parameterized using quantitative phosphoprotein expression data from cancer cell lines using reverse-phase protein microarrays. Quantitative PTEN protein expression was found to be the key determinant of resistance to anti-HER2 therapy in silico, which was predictive of unseen experiments in vitro using the PTEN inhibitor bp(V). When measured in cancer cell lines, PTEN expression predicts sensitivity to anti-HER2 therapy; furthermore, this quantitative measurement is more predictive of response (relative risk, 3.0; 95% confidence interval, 1.6-5.5; P biology approach has successfully been used to stratify patients for personalized therapy in cancer and is further compelling evidence that PTEN, appropriately measured in the clinical setting, refines clinical decision making in patients treated with anti-HER2 therapies.

  17. [ATPase and phosphatase activity of drone brood].

    Science.gov (United States)

    Bodnarchuk, L I; Stakhman, O S

    2004-01-01

    Most researches on insect enzymes concern carbohydrate and nitrogenous exchange. Data on ATPase activity for larval material of drone brood are absent in the available literature. The drone brood is one of the least investigated apiproducts. Allowing for the important role of ATPase in the vital functions of the insect cells our work was aimed at the study of ATPase of the drone blood activity and that of alkaline and acid phosphatases. When studying liophylised preparations of the drone brood homogenate we have found out high activity of Mg2+, Na+, K+-, Ca2+- and Mg2+-ATPase and of alkaline and acid phosphatase, that is the possible explanation of the high-intensity power and plastic processes proceeding during growth and development of larvae.

  18. Assessment and kinetics of soil phosphatase in Brazilian Savanna systems

    Directory of Open Access Journals (Sweden)

    ADÃO S. FERREIRA

    2016-06-01

    Full Text Available The activity and kinetics of soil phosphatases are important indicators to evaluate soil quality in specific sites such as the Cerrado (Brazilian Savanna. This study aimed to determine the activity and kinetic parameters of soil phosphatase in Cerrado systems. Soil phosphatase activity was assessed in samples of native Cerrado (NC, no-tillage (NT, conventional tillage (CT and pasture with Brachiaria brizantha (PBb and evaluated with acetate buffer (AB, tris-HCl buffer (TB, modified universal buffer (MUB and low MUB. The Michaelis-Menten equation and Eadie-Hofstee model were applied to obtain the kinetic parameters of soil phosphatase using different concentrations of p-nitrophenol phosphate (p-NPP. MUB showed the lowest soil phosphatase activity in all soils whereas AB in NC and NT presented the highest. Low MUB decreased interferences in the assessment of soil phosphatase activity when compared to MUB, suggesting that organic acids interfere on the soil phosphatase activity. In NC and NT, soil phosphatase activity performed with TB was similar to AB and low MUB. Km values from the Michaels-Menten equation were higher in NC than in NT, which indicate a lower affinity of phosphatase activity for the substrate in NC. Vmax values were also higher in NC than in NT. The Eadie-Hofstee model suggests that NC had more phosphatase isoforms than NT. The study showed that buffer type is of fundamental importance when assessing soil phosphatase activity in Cerrado soils.

  19. Gene Expression Analysis of an EGFR Indirectly Related Pathway Identified PTEN and MMP9 as Reliable Diagnostic Markers for Human Glial Tumor Specimens

    Directory of Open Access Journals (Sweden)

    Sergio Comincini

    2009-01-01

    Full Text Available In this study the mRNA levels of five EGFR indirectly related genes, EGFR, HB-EGF, ADAM17, PTEN, and MMP9, have been assessed by Real-time PCR in a panel of 37 glioblastoma multiforme specimens and in 5 normal brain samples; as a result, in glioblastoma, ADAM17 and PTEN expression was significantly lower than in normal brain samples, and, in particular, a statistically significant inverse correlation was found between PTEN and MMP9 mRNA levels. To verify if this correlation was conserved in gliomas, PTEN and MMP9 expression was further investigated in an additional panel of 16 anaplastic astrocytoma specimens and, in parallel, in different human normal and astrocytic tumor cell lines. In anaplastic astrocytomas PTEN expression was significantly higher than in glioblastoma multiforme, but no significant correlation was found between PTEN and MMP9 expression. PTEN and MMP9 mRNA levels were also employed to identify subgroups of specimens within the different glioma malignancy grades and to define a gene expression-based diagnostic classification scheme. In conclusion, this gene expression survey highlighted that the combined measurement of PTEN and MMP9 transcripts might represent a novel reliable tool for the differential diagnosis of high-grade gliomas, and it also suggested a functional link involving these genes in glial tumors.

  20. The dietary isothiocyanate sulforaphane modulates gene expression and alternative gene splicing in a PTEN null preclinical murine model of prostate cancer

    Directory of Open Access Journals (Sweden)

    Ball Richard Y

    2010-07-01

    Full Text Available Abstract Background Dietary or therapeutic interventions to counteract the loss of PTEN expression could contribute to the prevention of prostate carcinogenesis or reduce the rate of cancer progression. In this study, we investigate the interaction between sulforaphane, a dietary isothiocyanate derived from broccoli, PTEN expression and gene expression in pre malignant prostate tissue. Results We initially describe heterogeneity in expression of PTEN in non-malignant prostate tissue of men deemed to be at risk of prostate cancer. We subsequently use the mouse prostate-specific PTEN deletion model, to show that sulforaphane suppresses transcriptional changes induced by PTEN deletion and induces additional changes in gene expression associated with cell cycle arrest and apoptosis in PTEN null tissue, but has no effect on transcription in wild type tissue. Comparative analyses of changes in gene expression in mouse and human prostate tissue indicate that similar changes can be induced in humans with a broccoli-rich diet. Global analyses of exon expression demonstrated that sulforaphane interacts with PTEN deletion to modulate alternative gene splicing, illustrated through a more detailed analysis of DMBT1 splicing. Conclusion To our knowledge, this is the first report of how diet may perturb changes in transcription induced by PTEN deletion, and the effects of diet on global patterns of alternative gene splicing. The study exemplifies the complex interaction between diet, genotype and gene expression, and the multiple modes of action of small bioactive dietary components.

  1. Combined deletion of Pten and p53 in mammary epithelium accelerates triple-negative breast cancer with dependency on eEF2K.

    Science.gov (United States)

    Liu, Jeff C; Voisin, Veronique; Wang, Sharon; Wang, Dong-Yu; Jones, Robert A; Datti, Alessandro; Uehling, David; Al-awar, Rima; Egan, Sean E; Bader, Gary D; Tsao, Ming; Mak, Tak W; Zacksenhaus, Eldad

    2014-12-01

    The tumor suppressors Pten and p53 are frequently lost in breast cancer, yet the consequences of their combined inactivation are poorly understood. Here, we show that mammary-specific deletion of Pten via WAP-Cre, which targets alveolar progenitors, induced tumors with shortened latency compared to those induced by MMTV-Cre, which targets basal/luminal progenitors. Combined Pten-p53 mutations accelerated formation of claudin-low, triple-negative-like breast cancer (TNBC) that exhibited hyper-activated AKT signaling and more mesenchymal features relative to Pten or p53 single-mutant tumors. Twenty-four genes that were significantly and differentially expressed between WAP-Cre:Pten/p53 and MMTV-Cre:Pten/p53 tumors predicted poor survival for claudin-low patients. Kinome screens identified eukaryotic elongation factor-2 kinase (eEF2K) inhibitors as more potent than PI3K/AKT/mTOR inhibitors on both mouse and human Pten/p53-deficient TNBC cells. Sensitivity to eEF2K inhibition correlated with AKT pathway activity. eEF2K monotherapy suppressed growth of Pten/p53-deficient TNBC xenografts in vivo and cooperated with doxorubicin to efficiently kill tumor cells in vitro. Our results identify a prognostic signature for claudin-low patients and provide a rationale for using eEF2K inhibitors for treatment of TNBC with elevated AKT signaling.

  2. Physiological Roles for mafr-1 in Reproduction and Lipid Homeostasis

    Directory of Open Access Journals (Sweden)

    Akshat Khanna

    2014-12-01

    Full Text Available Maf1 is a conserved repressor of RNA polymerase (Pol III transcription; however, its physiological role in the context of a multicellular organism is not well understood. Here, we show that C. elegans MAFR-1 is functionally orthologous to human Maf1, represses the expression of both RNA Pol III and Pol II transcripts, and mediates organismal fecundity and lipid homeostasis. MAFR-1 impacts lipid transport by modulating intestinal expression of the vitellogenin family of proteins, resulting in cell-nonautonomous defects in the developing reproductive system. MAFR-1 levels inversely correlate with stored intestinal lipids, in part by influencing the expression of the lipogenesis enzymes fasn-1/FASN and pod-2/ACC1. Animals fed a high carbohydrate diet exhibit reduced mafr-1 expression and mutations in the insulin signaling pathway genes daf-18/PTEN and daf-16/FoxO abrogate the lipid storage defects associated with deregulated mafr-1 expression. Our results reveal physiological roles for mafr-1 in regulating organismal lipid homeostasis, which ensure reproductive success.

  3. Acid Phosphatase Development during Ripening of Avocado.

    Science.gov (United States)

    Sacher, J A

    1975-02-01

    The activity and subcellular distribution of acid phosphatase were assayed during ethylene-induced ripening of whole fruit or thick slices of avocado (Persea americana Mill. var. Fuerte and Hass). The activity increased up to 30-fold during ripening in both the supernatant fraction and the Triton X-100 extract of the precipitate of a 30,000g centrifugation of tissue homogenates from whole fruit or slices ripening in moist air. Enzyme activity in the residual precipitate after Triton extraction remained constant. The development of acid phosphatase in thick slices ripened in moist air was similar to that in intact fruit, except that enzyme development and ripening were accelerated about 24 hours in the slices. The increase in enzyme activity that occurs in slices ripening in moist air was inhibited when tissue sections were infiltrated with solutions, by aspiration for 2 minutes or by soaking for 2 hours, anytime 22 hours or more after addition of ethylene. This inhibition was independent of the presence or absence of cycloheximide or sucrose (0.3-0.5m). However, the large decline in enzyme activity in the presence of cycloheximide, as compared with the controls, indicated that synthesis of acid phosphatase was occurring at all stages of ripening.

  4. Feedback regulation on PTEN/AKT pathway by the ER stress kinase PERK mediated by interaction with the Vault complex

    DEFF Research Database (Denmark)

    Zhang, Wei; Neo, Suat Peng; Gunaratne, Jayantha

    2015-01-01

    The high proliferation rate of cancer cells, together with environmental factors such as hypoxia and nutrient deprivation can cause Endoplasmic Reticulum (ER) stress. The protein kinase PERK is an essential mediator in one of the three ER stress response pathways. Genetic and pharmacological...... inhibition of PERK has been reported to limit tumor growth in xenograft models. Here we provide evidence that inactive PERK interacts with the nuclear pore-associated Vault complex protein and that this compromises Vault-mediated nuclear transport of PTEN. Pharmacological inhibition of PERK under ER stress...... results is abnormal sequestration of the Vault complex, leading to increased cytoplasmic PTEN activity and lower AKT activation. As the PI3K/PTEN/AKT pathway is crucial for many aspects of cell growth and survival, this unexpected effect of PERK inhibitors on AKT activity may have implications...

  5. Monomeric tartrate resistant acid phosphatase induces insulin sensitive obesity.

    Directory of Open Access Journals (Sweden)

    Pernilla Lång

    Full Text Available BACKGROUND: Obesity is associated with macrophage infiltration of adipose tissue, which may link adipose inflammation to insulin resistance. However, the impact of inflammatory cells in the pathophysiology of obesity remains unclear. Tartrate resistant acid phosphatase (TRAP is an enzyme expressed by subsets of macrophages and osteoclasts that exists either as an enzymatically inactive monomer or as an active, proteolytically processed dimer. PRINCIPAL FINDINGS: Using mice over expressing TRAP, we show that over-expression of monomeric, but not the dimeric form in adipose tissue leads to early onset spontaneous hyperplastic obesity i.e. many small fat cells. In vitro, recombinant monomeric, but not proteolytically processed TRAP induced proliferation and differentiation of mouse and human adipocyte precursor cells. In humans, monomeric TRAP was highly expressed in the adipose tissue of obese individuals. In both the mouse model and in the obese humans the source of TRAP in adipose tissue was macrophages. In addition, the obese TRAP over expressing mice exhibited signs of a low-grade inflammatory reaction in adipose tissue without evidence of abnormal adipocyte lipolysis, lipogenesis or insulin sensitivity. CONCLUSION: Monomeric TRAP, most likely secreted from adipose tissue macrophages, induces hyperplastic obesity with normal adipocyte lipid metabolism and insulin sensitivity.

  6. Loss of SOX9 Expression Is Associated with PSA Recurrence in ERG-Positive and PTEN Deleted Prostate Cancers.

    Directory of Open Access Journals (Sweden)

    Christoph Burdelski

    Full Text Available The transcription factor SOX9 plays a crucial role in normal prostate development and has been suggested to drive prostate carcinogenesis in concert with PTEN inactivation. To evaluate the clinical impact of SOX9 and its relationship with key genomic alterations in prostate cancer, SOX9 expression was analyzed by immunohistochemistry on a tissue microarray containing 11,152 prostate cancers. Data on ERG status and deletions of PTEN, 3p13, 5q21 and 6q15 were available from earlier studies. SOX9 expression levels were comparable in luminal cells of normal prostate glands (50% SOX9 positive and 3,671 cancers lacking TMPRSS2:ERG fusion (55% SOX9 positive, but was markedly increased in 3,116 ERG-fusion positive cancers (81% SOX9 positive, p<0.0001. While no unequivocal changes in the SOX9 expression levels were found in different stages of ERG-negative cancers, a gradual decrease of SOX9 paralleled progression to advanced stage, high Gleason grade, metastatic growth, and presence of PTEN deletions in ERG-positive cancers (p<0.0001 each. SOX9 levels were unrelated to deletions of 3p, 5q, and 6q. Down-regulation of SOX9 expression was particularly strongly associated with PSA recurrence in ERG-positive tumors harboring PTEN deletions (p=0.001, but had no significant effect in ERG-negative cancers or in tumors with normal PTEN copy numbers. In summary, the results of our study argue against a tumor-promoting role of SOX9 in prostate cancer, but demonstrate that loss of SOX9 expression characterizes a particularly aggressive subset of ERG positive cancers harboring PTEN deletions.

  7. PCR-SSCP-DNA sequencing method in detecting PTEN gene mutation and its significance in human gastric cancer

    Institute of Scientific and Technical Information of China (English)

    Chuan-Yong Guo; Xuan-Fu Xu; Jian-Ye Wu; Shu-Fang Liu

    2008-01-01

    AIM: To discuss the possible effect of PTEN gene mutations on occurrence and development of gastric cancer.METHODS: Fifty-three gastric cancer specimens were selected to probe PTEN gene mutations in genome of gastric cancer and paracancerous tissues using PCR-SSCP-DNA sequencing method based on microdissection and to observe the protein expression by immunohistochemistry technique.RESULTS: PCR-SSCP-DNA sequencing indicated that 4 kinds of mutation sites were found in 5 of 53 gastric cancer specimens.One kind of mutation was found in exons.AA-TCC mutation was located at 40bp upstream of 3' lateral exert 7 (115946 AA-TCC).Such mutations led to terminator formation in the 297th codon of the PTEN gene.The other 3 kinds of mutation were found in introns,including a G-C point mutation at 91 bp upstream of 5' lateral exon 5(90896 G-C),a T-G point mutation at 24 bp upstream of 5' lateral exon 5 (90963 T-G),and a single base A mutation at 7 bp upstream of 5' lateral exon 5 (90980 A del).The PTEN protein expression in gastric cancer and paracancerous tissues detected using immunohistochemistry technique indicated that the total positive rate of PTEN protein expression was 66% in gastric cancer tissue,which was significantly lower than that (100%) in paracancerous tissues (P<0.005).CONCLUSION: PTEN gene mutation and expression may play an important role in the occurrence and development of gastric cancer.(C)2008 The WJG Press.All rights reserved.

  8. MDH2 Stimulated by Estrogen-GPR30 Pathway Down-Regulated PTEN Expression Promoting the Proliferation and Invasion of Cells in Endometrial Cancer

    Directory of Open Access Journals (Sweden)

    Yan Zhuang

    2017-04-01

    Full Text Available PURPOSE: The relationship between endometrial carcinoma and cellular metabolism is unknown. In endometrial cancer, mutation rate of PTEN has been reported very high. Malate dehydrogenase 2 (MDH2 is one of the isoforms of malate dehydrogenase, which is involved in citric acid cycle in mitochondria. Our study aimed to investigate the role MDH2 played in PTEN-regulated endometrial carcinoma. METHODS: To reveal the expression of MDH2 and the co-localization of PTEN and MDH2, immunohistochemistry and immunofluorescent staining were used. Western blot, Real-time PCR, RNA interference and overexpression plasmid DNA transfection were performed to investigate the relationship between PTEN and MDH2 as well as the impact of E2 on the expression of PTEN and MDH2, while CCK8, transwell and flow cytometric analysis were carried out to evaluate the proliferation, migration and invasion and apoptosis of endometrial carcinoma cell lines. RESULTS: Our results demonstrated that as a metabolism related enzyme, MDH2 was overexpressed in endometrial carcinoma tissues and related to the grade of the cancer (P = .038. Western blot, Real-time PCR and immunofluorescent staining revealed MDH2 inhibited the expression of PTEN and was co-localized with PTEN in the cytoplasm of endometrial carcinoma. Proliferation, transwell and apoptosis assay suggested that MDH2 enhanced the proliferation, migration and invasion but inhibited the apoptosis of endometrial cancer cell line through suppressing PTEN. Furthermore, E2 inhibited the expression level of PTEN but enhanced MDH2 via GPR30. CONCLUSIONS: Our study demonstrated that MDH2, stimulated by estrogen, was involved in the development of PTEN-regulated endometrial carcinoma through GPR30-related pathway.

  9. [Ursolic acid as antitumor agent and inductor of PTEN and brown fat].

    Science.gov (United States)

    Bershteĭn, L M

    2012-01-01

    In this mini-review the basic evidence about anticancer properties of ursolic acid (UA), the compound belonging to the class of triterpenoids, is given. Beside inhibiting tumor cell growth in vitro and in vivo and activating of apoptosis, UA (as well as some other related and not related compounds) is capable to induce PTEN (a tumor suppressor mutation of which is rather often discovered in human tumors including endometrial cancer type I) and amount/activity of brown fat. The latter action may explain obesity-preventing capacity of UA that also may lead to an additional antiblastomogenic effect.

  10. Targeting notch pathway enhances rapamycin antitumor activity in pancreas cancers through PTEN phosphorylation

    Directory of Open Access Journals (Sweden)

    Vo Kevin

    2011-11-01

    Full Text Available Abstract Background Pancreas cancer is one of most aggressive human cancers with the survival rate for patients with metastatic pancreas cancer at 5-6 months. The poor survival demonstrates a clear need for better target identification, drug development and new therapeutic strategies. Recent discoveries have shown that the role for Notch pathway is important in both development and cancer. Its contribution to oncogenesis also involves crosstalks with other growth factor pathways, such as Akt and its modulator, PTEN. The mounting evidence supporting a role for Notch in cancer promotion and survival suggests that targeting this pathway alone or in combination with other therapeutics represents a promising therapeutic strategy. Results Using a pancreas cancer tissue microarray, we noted that Jagged1, Notch3 and Notch4 are overexpressed in pancreas tumors (26%, 84% and 31% respectively, whereas Notch1 is expressed in blood vessels. While there was no correlation between Notch receptor expression and survival, stage or tumor grade, Notch3 was associated with Jagged1 and EGFR expression, suggesting a unique relationship between Notch3 and Jagged1. Inhibition of the Notch pathway genetically and with gamma-secretase inhibitor (GSI resulted in tumor suppression and enhanced cell death. The observed anti-tumor activity appeared to be through Akt and modulation of PTEN phosphorylation. We discovered that transcriptional regulation of RhoA by Notch is important for PTEN phosphorylation. Finally, the mTOR inhibitor Rapamycin enhanced the effect of GSI on RhoA expression, resulting in down regulation of phospho-Akt and increased in vitro tumor cytotoxity. Conclusions Notch pathway plays an important role in maintaining pancreas tumor phenotype. Targeting this pathway represents a reasonable strategy for the treatment of pancreas cancers. Notch modulates the Akt pathway through regulation of PTEN phosphorylation, an observation that has not been made

  11. Widespread presence of "bacterial-like" PPP phosphatases in eukaryotes

    Directory of Open Access Journals (Sweden)

    Andreeva Alexandra V

    2004-11-01

    Full Text Available Abstract Background In eukaryotes, PPP (protein phosphatase P family is one of the two known protein phosphatase families specific for Ser and Thr. The role of PPP phosphatases in multiple signaling pathways in eukaryotic cell has been extensively studied. Unlike eukaryotic PPP phosphatases, bacterial members of the family have broad substrate specificity or may even be Tyr-specific. Moreover, one group of bacterial PPPs are diadenosine tetraphosphatases, indicating that bacterial PPP phosphatases may not necessarily function as protein phosphatases. Results We describe the presence in eukaryotes of three groups of expressed genes encoding "non-conventional" phosphatases of the PPP family. These enzymes are more closely related to bacterial PPP phosphatases than to the known eukaryotic members of the family. One group, found exclusively in land plants, is most closely related to PPP phosphatases from some α-Proteobacteria, including Rhizobiales, Rhodobacterales and Rhodospirillaceae. This group is therefore termed Rhizobiales / Rhodobacterales / Rhodospirillaceae-like phosphatases, or Rhilphs. Phosphatases of the other group are found in Viridiplantae, Rhodophyta, Trypanosomatidae, Plasmodium and some fungi. They are structurally related to phosphatases from psychrophilic bacteria Shewanella and Colwellia, and are termed Shewanella-like phosphatases, or Shelphs. Phosphatases of the third group are distantly related to ApaH, bacterial diadenosine tetraphosphatases, and are termed ApaH-like phosphatases, or Alphs. Patchy distribution of Alphs in animals, plants, fungi, diatoms and kinetoplasts suggests that these phosphatases were present in the common ancestor of eukaryotes but were independently lost in many lineages. Rhilphs, Shelphs and Alphs form PPP clades, as divergent from "conventional" eukaryotic PPP phosphatases as they are from each other and from major bacterial clades. In addition, comparison of primary structures revealed a

  12. PTEN protein loss is associated with an increased risk of recurrence in Chinese patients after prostatectomy for clinically localized prostate cancer%PTEN蛋白缺失与中国前列腺癌患者根治术后生化复发风险关系的研究

    Institute of Scientific and Technical Information of China (English)

    王涛; 杨晓群; 孙娟娟; 甘华磊; 王朝夫

    2015-01-01

    背景与目的:张力蛋白同源第10号染色体缺失的磷酸酶基因(phosphatase and tensin homolog deleted on chromosome 10,PTEN)缺失是西方国家前列腺癌中最常见的基因异常之一,与肿瘤的进展、预后均有一定相关性。鉴于前列腺癌的异质性,不同地区、人群间其基因表达谱存在广泛差异,本研究主要探讨PTEN蛋白缺失在中国前列腺癌患者中的发生率以及与生化复发的相关性。方法:选取2006—2011年225例局限性前列腺癌并采取根治切除术的患者为研究对象,回顾性收集所有患者的临床病理资料,包括确诊时年龄、血清前列腺特异性抗原(prostate-specific antigen,PSA)值、Gleason分级评分、TNM分期、手术切缘和术后生化复发与否及时间。将225例局限性前列腺癌根治切除标本的肿瘤组织及癌旁组织制成组织芯片(tissue microarray,TMA),采用免疫组织化学技术检测PTEN蛋白在肿瘤及癌旁组织中的表达。采用χ2检验分析前列腺癌组织中PTEN蛋白缺失与患者临床病理特征的相关性。运用Kaplan-Meier生存分析模型、Cox比例风险模型分析PTEN蛋白缺失及患者临床病理特征与生化复发的关系。结果:前列腺癌患者中PTEN蛋白缺失率为15%(33/217),且存在PTEN蛋白缺失的前列腺癌患者其确诊时血清PSA值(P=0.030)及年龄(P=0.009)要显著高于PTEN表达的前列腺癌患者。单因素生存分析显示,PTEN表达情况(P=0.0131)、确诊时血清PSA值(P=0.0004)和Gleason分级评分(P=0.0198)与前列腺癌患者的生化复发相关。Cox多因素分析结果表明,PTEN蛋白表达情况(HR=0.536,P=0.044)、确诊时血清PSA值(HR=1.879,P=0.001)和Gleason分级评分(HR=1.361,P=0.030)为前列腺癌患者生化复发的独立预后因素。结论:PTEN蛋白表达情况是局限性前列腺癌患者根治术后生化复发的独立预后因素,检测PTEN蛋白有望改善根治术

  13. SIGNIFICANCE OF Skp2 EXPRESSION IN HUMAN GASTRIC CARCINOMA AND THE RELATIONSHIP BETWEEN Skp2,p27 AND PTEN EXPRESSION

    Institute of Scientific and Technical Information of China (English)

    MA Xiu-mei; ZUO Lian-fu

    2005-01-01

    Objective: S-phase kinase-associated protein 2 (Skp2) is a positive regulator of G1-S transition and promotes ubiquitin-mediated proteolysis of the cyclin-dependent kinase inhibitor p27. Its overexpression has been implicated in cell transformation and oncogenesis. In this study, we investigated significance of Skp2 expression in human gastric carcinoma and the relationship between Skp2, p27 and PTEN expression. Methods: Immunohistochemical analysis was performed on 138 surgical resected primary gastric carcinoma specimens, 102 paired metastasis carcinoma tissue specimens in lymph node from the same set of 138 surgical resected primary gastric carcinoma specimens, 30 dysplasia specimens, 30 intestinal metaplasia specimens, and 20 normal gastric mucosa specimens for Skp2 and performed on the same set of 138 surgical resected primary gastric carcinoma specimens for p27 and PTEN. Results: Skp2 labeling frequency % was increased dramatically in intestinal metaplasia, dysplasia, and primary gastric carcinoma compared with normal gastric mucosa (P=0.000, all the same). Skp2 labeling frequency % in metastasis gastric carcinoma in lymph node was significantly higher than primary gastric carcinoma (P=0.037). Skp2 labeling frequency % was positively associated with differentiated degree (rho=0.315, P=0.000), vessel invasion (rho=0.303, P=0.000) and lymph node metastasis (rho=0.254, P=0.000) respectively.An inverse correlation of Skp2 was observed with both its biochemical target p27 expression in gastric carcinoma (rho=-0.451, P=0.000) and with its putative negative regulator, the PTEN tumor suppressor protein (rho=-0.480, P=0.000).p27 expression had positive relationship with PTEN expression in gastric carcinoma (rho=0.642, P=0.000). Conclusion:Skp2 overexpression is correlated with carcinogenesis and progression of gastric carcinoma: elevated Skp2 expression is correlated with decreased p27 and PTEN in gastric carcinoma, and p27 expression is parallel with PTEN expression

  14. 视网膜母细胞瘤组织中 Ki-67、PTEN 表达的变化%Expressions of Ki-67 and PTEN in the Retinoblastoma

    Institute of Scientific and Technical Information of China (English)

    孟海洋

    2016-01-01

    Objective To investigate the expressions of Ki-67 and PTEN in the retinoblastoma and the signifi-cance. Methods Immunohistochemical S-P method was used to detect the expressions of Ki-67 and PTEN in the 97 patients with retinoblastoma and 28 patients with normal retina tissues,their relationship with clinicopathological pa-rameters were analyzed. Results The positive rate of Ki-67 was 66. 0%(64 / 97)in the retinoblastoma,and was 14. 3%(4 / 28)in the normal retina tissues( χ2 = 23. 406,P < 0. 05). The positive rate of Ki-67 was 53. 6%(52 / 97)in the retinoblastoma,and was 92. 9%(26 / 28)in the normal retina tissues(χ2 = 14. 266,P < 0. 05). The expressions of Ki-67 and PTEN in the retinoblastoma were related with cell differentiation degree and clinical stage (P < 0. 05). In the retinoblastoma,the expression of Ki-67 was negatively related with PTEN(r = - 0. 493,P <0. 05). Conclusion Abnormal expressions of Ki-67 and PTEN may be related to the infiltration and development of retinoblastoma.%目的:探讨视网膜母细胞瘤组织中 Ki-67、PTEN 表达的变化及其临床意义。方法采用免疫组化S-P 法检测97例视网膜母细胞瘤和28例正常视网膜组织中 Ki-67、PTEN 的表达水平,并分析两者与视网膜母细胞瘤临床病理参数的关系。结果视网膜母细胞瘤组织中 Ki-67的阳性率为66.0%(64/97),高于正常视网膜组织的14.3%(4/28)(χ2=23.406,P <0.05);视网膜母细胞瘤组织中 PTEN 的阳性率为53.6%(52/97),低于正常视网膜组织的92.9%(26/28)(χ2=14.266,P <0.05)。视网膜母细胞瘤组织中 Ki-67、PTEN 的表达均与患者的分化程度、临床分期有关(P <0.05)。视网膜母细胞瘤组织中 Ki-67、PTEN 的表达呈负相关关系(r =-0.493,P <0.05)。结论 Ki-67、PTEN 的异常表达参与了视网膜母细胞瘤的侵袭和病程进展。

  15. Primary structure of rat secretory acid phosphatase and comparison to other acid phosphatases.

    Science.gov (United States)

    Roiko, K; Jänne, O A; Vihko, P

    1990-05-14

    Overlapping cDNA clones encoding rat prostatic acid phosphatase (rPAP) were isolated by using two human prostatic acid phosphatase (hPAP)-encoding cDNAs to screen rat prostatic cDNA libraries. The isolated cDNAs encompassed a total of 1626 nucleotides (nt), of which 1143 nt corresponded to the protein coding sequence encoding a mature polypeptide of 350 amino acids (aa) and a 31-aa long signal peptide-like sequence. The deduced Mr of the mature rPAP was 40,599. RNA blot analysis indicated the presence of three mRNA species (4.9, 2.3 and 1.5 kb in size) in the rat prostate. The deduced aa sequences of rPAP and hPAP show 75% identity, whereas the similarity between rPAP and human lysosomal acid phosphatase (hLAP) is only 45%. Furthermore, the sequence similarity between rPAP and rat lysosomal acid phosphatase (rLAP) is 46% at the aa level. Similar to hPAP, but unlike hLAP and rLAP, the rPAP sequence lacks a membrane-anchoring domain indicating the secretory character of this phosphatase. All six cysteines present in the overlapping areas of the mature rPAP, hPAP, rLAP and hLAP proteins are positionally conserved, suggesting that these residues are important for the tertiary structure of acid phosphatases (APs). The previously reported active site residues, two arginines and one histidine, are also conserved in these APs.

  16. Phospholipid metabolism and nuclear function: roles of the lipin family of phosphatidic acid phosphatases.

    Science.gov (United States)

    Siniossoglou, Symeon

    2013-03-01

    Phospholipids play important roles in nuclear function as dynamic building blocks for the biogenesis of the nuclear membrane, as well as signals by which the nucleus communicates with other organelles, and regulate a variety of nuclear events. The mechanisms underlying the nuclear roles of phospholipids remain poorly understood. Lipins represent a family of phosphatidic acid (PA) phosphatases that are conserved from yeasts to humans and perform essential functions in lipid metabolism. Several studies have identified key roles for lipins and their regulators in nuclear envelope organization, gene expression and the maintenance of lipid homeostasis in yeast and metazoans. This review discusses recent advances in understanding the roles of lipins in nuclear structure and function. This article is part of a Special Issue entitled Phospholipids and Phospholipid Metabolism. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. Auxiliary phosphatases in two-component signal transduction.

    Science.gov (United States)

    Silversmith, Ruth E

    2010-04-01

    Signal termination in two-component systems occurs by loss of the phosphoryl group from the response regulator protein. This review explores our current understanding of the structures, catalytic mechanisms and means of regulation of the known families of phosphatases that catalyze response regulator dephosphorylation. The CheZ and CheC/CheX/FliY families, despite different overall structures, employ identical catalytic strategies using an amide side chain to orient a water molecule for in-line attack of the aspartyl phosphate. Spo0E phosphatases contain sequence and structural features that suggest a strategy similar to the chemotaxis phosphatases but the mechanism used by the Rap phosphatases is not yet elucidated. Identification of features shared by phosphatase families may aid in the identification of currently unrecognized classes of response regulator phosphatases. Copyright 2010 Elsevier Ltd. All rights reserved.

  18. Low serum alkaline phosphatase activity in Wilson's disease.

    Science.gov (United States)

    Shaver, W A; Bhatt, H; Combes, B

    1986-01-01

    Low values for serum alkaline phosphatase activity were observed early in the course of two patients with Wilson's disease presenting with the combination of severe liver disease and Coombs' negative acute hemolytic anemia. A review of other cases of Wilson's disease revealed that 11 of 12 patients presenting with hemolytic anemia had values for serum alkaline phosphatase less than their respective sex- and age-adjusted mean values; in eight, serum alkaline phosphatase activity was less than the lower value for the normal range of the test. Low values for serum alkaline phosphatase were much less common in Wilson's disease patients with more chronic forms of presentation. Copper added in high concentration to serum in vitro did not have an important effect on serum alkaline phosphatase activity. The mechanism responsible for the decrease in serum alkaline phosphatase activity in patients is uncertain.

  19. Tangeretin induces cell cycle arrest and apoptosis through upregulation of PTEN expression in glioma cells.

    Science.gov (United States)

    Ma, Li-Li; Wang, Da-Wei; Yu, Xu-Dong; Zhou, Yan-Ling

    2016-07-01

    Tangeretin (TANG), present in peel of citrus fruits, has been shown to various medicinal properties such as chemopreventive and neuroprotective. However, the chemopreventive effect of TANG on glioblastoma cells has not been examined. The present study was designed to explore the anticancer potential of TANG in glioblastoma cells and to investigate the related mechanism. Human glioblastoma U-87MG and LN-18 cells were treated with 45μM concentration of TANG and cell growth was measured by MTT assay. The cell cycle distribution and cell death were measured by flow cytometry. The expression of cell cycle and apoptosis related genes were analyzed by quantitative RT-PCR and western blot. The cells treated with TANG were significantly increased cell growth suppression and cell death effects than vehicle treated cells. Further, TANG treatment increases G2/M arrest and apoptosis by modulating PTEN and cell-cycle regulated genes such as cyclin-D and cdc-2 mRNA and protein expressions. Moreover, the ability of TANG to decrease cell growth and to induce cell death was compromised when PTEN was knockdown by siRNA. Taken together, the chemopreventive effect of TANG is associated with regulation of cell-cycle and apoptosis in glioblastoma, thereby attenuating glioblastoma cell growth. Hence, the present findings suggest that TANG may be a therapeutic agent for glioblastoma treatment.

  20. Sphingoid base 1-phosphate phosphatase: A key regulator of sphingolipid metabolism and stress response

    Science.gov (United States)

    Mandala, Suzanne M.; Thornton, Rosemary; Tu, Zhenxing; Kurtz, Myra B.; Nickels, Joseph; Broach, James; Menzeleev, Ramil; Spiegel, Sarah

    1998-01-01

    The sphingolipid metabolites ceramide and sphingosine-1-phosphate are second messengers with opposing roles in mammalian cell growth arrest and survival; their relative cellular level has been proposed to be a rheostat that determines the fate of cells. This report demonstrates that this rheostat is an evolutionarily conserved stress-regulatory mechanism that influences growth and survival of yeast. Although the role of sphingosine-1-phosphate in yeast was not previously examined, accumulation of ceramide has been shown to induce G1 arrest and cell death. We now have identified a gene in Saccharomyces cerevisiae, LBP1, that regulates the levels of phosphorylated sphingoid bases and ceramide. LBP1 was cloned from a yeast mutant that accumulated phosphorylated long-chain sphingoid bases and diverted sphingoid base intermediates from sphingolipid pathways to glycerophospholipid biosynthesis. LBP1 and its homolog, LBP2, encode very hydrophobic proteins that contain a novel-conserved sequence motif for lipid phosphatases, and both have long-chain sphingoid base phosphate phosphatase activity. In vitro characterization of Lbp1p shows that this phosphatase is Mg2+-independent with high specificity for phosphorylated long-chain bases, phytosphingosine and sphingosine. The deletion of LBP1 results in the accumulation of phosphorylated long-chain sphingoid bases and reduced ceramide levels. Moreover, deletion of LBP1 and LBP2 results in dramatically enhanced survival upon severe heat shock. Thus, these phosphatases play a previously unappreciated role in regulating ceramide and phosphorylated sphingoid base levels in yeast, and they modulate stress responses through sphingolipid metabolites in a manner that is reminiscent of their effects on mammalian cells. PMID:9419344

  1. Membrane Topology and Biochemical Characterization of the Escherichia coli BacA Undecaprenyl-Pyrophosphate Phosphatase.

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    Guillaume Manat

    Full Text Available Several integral membrane proteins exhibiting undecaprenyl-pyrophosphate (C55-PP phosphatase activity were previously identified in Escherichia coli that belonged to two distinct protein families: the BacA protein, which accounts for 75% of the C55-PP phosphatase activity detected in E. coli cell membranes, and three members of the PAP2 phosphatidic acid phosphatase family, namely PgpB, YbjG and LpxT. This dephosphorylation step is required to provide the C55-P carrier lipid which plays a central role in the biosynthesis of various cell wall polymers. We here report detailed investigations of the biochemical properties and membrane topology of the BacA protein. Optimal activity conditions were determined and a narrow-range substrate specificity with a clear preference for C55-PP was observed for this enzyme. Alignments of BacA protein sequences revealed two particularly well-conserved regions and several invariant residues whose role in enzyme activity was questioned by using a site-directed mutagenesis approach and complementary in vitro and in vivo activity assays. Three essential residues Glu21, Ser27, and Arg174 were identified, allowing us to propose a catalytic mechanism for this enzyme. The membrane topology of the BacA protein determined here experimentally did not validate previous program-based predicted models. It comprises seven transmembrane segments and contains in particular two large periplasmic loops carrying the highly-conserved active site residues. Our data thus provide evidence that all the different E. coli C55-PP phosphatases identified to date (BacA and PAP2 catalyze the dephosphorylation of C55-PP molecules on the same (outer side of the plasma membrane.

  2. Genetic interaction network of the Saccharomyces cerevisiae type 1 phosphatase Glc7

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    Neszt Michael

    2008-07-01

    Full Text Available Abstract Background Protein kinases and phosphatases regulate protein phosphorylation, a critical means of modulating protein function, stability and localization. The identification of functional networks for protein phosphatases has been slow due to their redundant nature and the lack of large-scale analyses. We hypothesized that a genome-scale analysis of genetic interactions using the Synthetic Genetic Array could reveal protein phosphatase functional networks. We apply this approach to the conserved type 1 protein phosphatase Glc7, which regulates numerous cellular processes in budding yeast. Results We created a novel glc7 catalytic mutant (glc7-E101Q. Phenotypic analysis indicates that this novel allele exhibits slow growth and defects in glucose metabolism but normal cell cycle progression and chromosome segregation. This suggests that glc7-E101Q is a hypomorphic glc7 mutant. Synthetic Genetic Array analysis of glc7-E101Q revealed a broad network of 245 synthetic sick/lethal interactions reflecting that many processes are required when Glc7 function is compromised such as histone modification, chromosome segregation and cytokinesis, nutrient sensing and DNA damage. In addition, mitochondrial activity and inheritance and lipid metabolism were identified as new processes involved in buffering Glc7 function. An interaction network among 95 genes genetically interacting with GLC7 was constructed by integration of genetic and physical interaction data. The obtained network has a modular architecture, and the interconnection among the modules reflects the cooperation of the processes buffering Glc7 function. Conclusion We found 245 genes required for the normal growth of the glc7-E101Q mutant. Functional grouping of these genes and analysis of their physical and genetic interaction patterns bring new information on Glc7-regulated processes.

  3. Plumbagin Inhibits Prostate Carcinogenesis in Intact and Castrated PTEN Knockout Mice via Targeting PKCε, Stat3, and Epithelial-to-Mesenchymal Transition Markers.

    Science.gov (United States)

    Hafeez, Bilal Bin; Fischer, Joseph W; Singh, Ashok; Zhong, Weixiong; Mustafa, Ala; Meske, Louise; Sheikhani, Mohammad Ozair; Verma, Ajit Kumar

    2015-05-01

    Prostate cancer continues to remain the most common cancer and the second leading cause of cancer-related deaths in American males. The Pten deletions and/or mutations are frequently observed in both primary prostate cancers and metastatic prostate tissue samples. Pten deletion in prostate epithelium in mice results in prostatic intraepithelial neoplasia (PIN), followed by progression to invasive adenocarcinoma. The Pten conditional knockout mice [(Pten-loxp/loxp:PB-Cre4(+)) (Pten-KO)] provide a unique preclinical model to evaluate agents for efficacy for both the prevention and treatment of prostate cancer. We present here for the first time that dietary plumbagin, a medicinal plant-derived naphthoquinone (200 or 500 ppm) inhibits tumor development in intact as well as castrated Pten-KO mice. Plumbagin has shown no signs of toxicity at either of these doses. Plumbagin treatment resulted in a decrease expression of PKCε, AKT, Stat3, and COX2 compared with the control mice. Plumbagin treatment also inhibited the expression of vimentin and slug, the markers of epithelial-to-mesenchymal transition (EMT) in prostate tumors. In summary, the results indicate that dietary plumbagin inhibits growth of both primary and castration-resistant prostate cancer (CRPC) in Pten-KO mice, possibly via inhibition of PKCε, Stat3, AKT, and EMT markers (vimentin and slug), which are linked to the induction and progression of prostate cancer.

  4. Serum proteins, trace metals and phosphatases in psoriasis

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    Bhatnagar M

    1994-01-01

    Full Text Available Serum proteins, zinc, copper, acid phosphatase (AcPase and alkaline phosphatase (AlPase were studied in both active and remission phases of psoriasis. Data were compared with healthy controls, ?1, ? and ? globulins were high in active phase while ?1 and ? globulins were at par in remission phase. Serum copper was low but zinc and alkaline phosphatase were significantly high in both active and remission phases of the disease. Acid phosphatase level was at par in all the experimental groups. Study suggests a positive correlation of globulin, zinc and Alpase in active and remission phase of psoriasis.

  5. [Effect of VAM fungi on phosphatase activity in maize rhizosphere].

    Science.gov (United States)

    Song, Y; Li, X; Feng, G

    2001-08-01

    The effect of VAM fungi on phosphatase activity in maize rhizosphere was examined by pot culture experiment, in which, three-compartment-pots were used, the central compartment being separated from the outer two by a nylon net with 30 microns mesh. Plants were harvested 70 days after planting. Soil acid and alkaline phosphatase were measured at different distances from root surface. The results showed that VAM increased the activities of soil acid and alkaline phosphatase in the rhizosphere. It was found that different phosphorous sources had different effects on phosphatase activity.

  6. miRNA-21 promotes proliferation and invasion of triple-negative breast cancer cells through targeting PTEN

    Science.gov (United States)

    Fang, Hong; Xie, Jiping; Zhang, Min; Zhao, Ziwei; Wan, Yi; Yao, Yongqiang

    2017-01-01

    MicroRNAs (miRNAs) are small single-stranded RNAs that bind to the 3’UTR of the mRNAs of target genes. They can target multiple genes and regulate translation or degradation of the mRNA. miRNAs target genes in a tissue-specific manner, and the role of a particular miRNA varies according to tumor origin or even subtype within the same cancer. This study evaluated the effect of miR-21 expression in triple-negative breast cancer (TNBC) tissues and MDA-MB-468, a cell line derived from TNBC tissues. miR-21 was consistently upregulated in TNBC and MDA-MB-468 cells compared to normal tissues. Inhibition of miR-21 by miR-21 antisense oligonucleotides decreased the proliferation, viability, and invasiveness of MDA-MB-468 cells and enhanced apoptosis. Furthermore, we confirmed that PTEN was downregulated by miR-21 in MDA-MB-468 cells. The results indicated that PTEN may mediate the oncogenic properties of miR-21 in TNBC. In summary, miR-21 was upregulated in TNBC tissues and cells, and promoted the proliferation and invasion of MDA-MB-468 cells, but negatively regulated the expression of PTEN protein. Inhibition of miR-21 or overexpression of PTEN protein could be promising strategies for the treatment of patients with TNBC.

  7. PI3K/Akt/mTOR signaling & its regulator tumour suppressor genes PTEN & LKB1 in human uterine leiomyomas

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    Annu Makker

    2016-01-01

    Interpretation & conclusions: Upregulation of PTEN and LKB1 in concert with negative or low levels of activated Akt, mTOR and S6 indicates that PI3K/Akt/mTOR pathway may not play a significant role in pathogenesis of leiomyoma.

  8. Changes in immunoexpression of p53, Ki-67, Ets-1, APAF-1 and PTEN in serrated and conventional colon adenomas.

    Science.gov (United States)

    Pap, Zsuzsánna; Ilyés, Izabella Ágota; Mocan, Simona Liliana; Dénes, Lóránd; Muică Nagy-Bota, Monica Cristina; Pávai, Zoltán; Szántó, Annamária

    2015-01-01

    The balance between apoptosis and proliferation is tipped towards a decrease of apoptosis as the colonocyte progresses in the adenoma to carcinoma sequence of colon carcinogenesis. According to literature data, proteins like p53, Ki-67, APAF-1, Ets-1, PTEN contribute to inhibition of apoptosis and stimulation of proliferation. Considering the complex interference among colorectal carcinogenetic mechanisms, our aim was to study the markers Ets-1 and APAF-1 relative to p53, Ki-67 and PTEN expression in colon adenomas/polyps (A/P). We performed immunohistochemistry on 99 colon A/P cases from the material of the Department of Pathology, Emergency County Hospital of Tirgu Mures, Romania. Secondary EnVision Flex/HRP (Horseradish peroxidase) (20 minutes) was used for signal amplification. The majority of A/P show increased Ki-67, p53, Ets-1 expression, decreased APAF-1 expression and preserved PTEN expression. p53, Ki-67, Ets-1 and APAF-1 demonstrated statistically significant correlations with histological type and grade of dysplasia. We also observed that expression of these proteins in the intestinal crypts has a typical distribution according to histological type and grade of dysplasia. In case of hyperplastic polyps APAF-1 expression decreases as p53 and Ki-67 expression increases, followed by a decrease in PTEN expression in serrated adenomas, and an increase of Ets-1 expression in conventional adenomas.

  9. Impact of Prostate Inflammation on Lesion Development in the POET3+Pten+/− Mouse Model of Prostate Carcinogenesis

    Science.gov (United States)

    Burcham, Grant N.; Cresswell, Gregory M.; Snyder, Paul W.; Chen, Long; Liu, Xiaoqi; Crist, Scott A.; Henry, Michael D.; Ratliff, Timothy L.

    2015-01-01

    Evidence linking prostatitis and prostate cancer development is contradictory. To study this link, the POET3 mouse, an inducible model of prostatitis, was crossed with a Pten-loss model of prostate cancer (Pten+/−) containing the ROSA26 luciferase allele to monitor prostate size. Prostatitis was induced, and prostate bioluminescence was tracked over 12 months, with lesion development, inflammation, and cytokine expression analyzed at 4, 8, and 12 months and compared with mice without induction of prostatitis. Acute prostatitis led to more proliferative epithelium and enhanced bioluminescence. However, 4 months after initiation of prostatitis, mice with induced inflammation had lower grade pre-neoplastic lesions. A trend existed toward greater development of carcinoma 12 months after induction of inflammation, including one of two mice with carcinoma developing perineural invasion. Two of 18 mice at the later time points developed lesions with similarities to proliferative inflammatory atrophy, including one mouse with associated carcinoma. Pten+/− mice developed spontaneous inflammation, and prostatitis was similar among groups of mice at 8 and 12 months. Analyzed as one cohort, lesion number and grade were positively correlated with prostatitis. Specifically, amounts of CD11b+Gr1+ cells were correlated with lesion development. These results support the hypothesis that myeloid-based inflammation is associated with lesion development in the murine prostate, and previous bouts of CD8-driven prostatitis may promote invasion in the Pten+/− model of cancer. PMID:25455686

  10. Role of PTEN protein in spinal cord neurons in diabetic neuropathic pain in rats%脊髓神经元PTEN蛋白在大鼠糖尿病神经痛中的作用

    Institute of Scientific and Technical Information of China (English)

    黄振兴; 黄腾; 何万友; 贺俭; 王汉兵; 杨承祥; 周俊

    2016-01-01

    目的 探讨脊髓神经元第10号染色体同源缺失性磷酸酶张力蛋白基因(PTEN)蛋白在大鼠糖尿病神经痛中的作用.方法 雄性SD大鼠,2月龄,体重180 ~ 200 g,采用腹腔注射1%链脲佐菌素(STZ) 60 mg/kg的方法制备糖尿病模型.取糖尿病神经痛大鼠16只,采用随机数字表法,将其分为2组(n=8):糖尿病神经痛组(DNP组)和糖尿病神经痛+PTEN蛋白抑制剂bpv组(DPN-bpv组);另取16只大鼠,采用随机数字表法,将其分为2组(n=8):对照组(C组)和bpv组.DNP-bpv和bpv组于注射STZ后14-28 d时腹腔注射bpv 0.2 mg/kg,1次/d.分别于注射STZ前(T1)、注射STZ后2、7、14、21、28 d(T2-6)时测定机械缩足反应阈(MWT),测定MWT后处死大鼠,取L45脊髓组织,采用ELISA法检测PTEN蛋白活性,采用Western blot法检测丝氨酸/苏氨酸蛋白激酶(Akt)(s473)磷酸化水平.结果 与C组比较,DNP组和DNP-bpv组T4-6时MWT降低,脊髓PTEN蛋白活性和Akt(s473)磷酸化水平升高(P<0.05或0.01);与DNP组比较,DNP-bpv组T6时MWT升高,脊髓PTEN蛋白活性和Akt(s473)磷酸化水平降低(P<0.05).结论 脊髓神经元PTEN蛋白参与了大鼠糖尿病神经痛的维持.%Objective To investigate the role of phosphatase and tensin homologue deleted on chromosome 10 (PTEN) protein in the spinal cord neurons in diabetic neuropathic pain (DNP) in rats.Methods Male Sprague-Dawley rats,aged 2 months,weighing 180-200 g,were studied.Diabetes mellitus was induced by single intraperitoneal injection of streptozotocin (STZ) 60 mg/kg.Sixteen rats with DNP were randomly divided into 2 groups (n =8 each) using a random number table:DNP group and DNP+PTEN inhibitor bpv (pic) group (DPN-bpv group).Another 16 rats were equally and randomly divided into either control group (group C) or bpv group.In DNP-bpv and bpv groups,bpv (pic) 0.2mg/kg was injected intraperitoneally once a day within 14-28 days after injection of STZ.Before STZ injection (T1),and at 2,7,14,21 and 28 days after STZ

  11. 骨肉中PTEN蛋白表达及临床意义的研究%Expression and clinical significance of PTEN protein in osteosarcoma

    Institute of Scientific and Technical Information of China (English)

    Yubin Wang; Anmin Chen; Fengjin Guo; Yujun Xia

    2008-01-01

    Objective:To investigate the expression and significance of cancer inhibitory gene PTEN protein in osteosarcoma.To analyze the level of its expression in different histological classification of osteosarcoma.To determine the possibility of taking PTEN protein as a marker gene for diagnosing osteosarcoma.To observe the clinical value of PTEN expression levels as a reference index for osteosarcoma classification.Methods:43 specimens collected from osteosarcoma excision were studied.30 specimens collected during the same period from benign lesion of bone (osteochondroma) operation were taken as the control group.Immunohistochemistry staining (ElivisonTM two steps method) was used to detect the expression of PTEN protein in 43 cases of osteosarcoma.SPSS 10.0 was used in statistical analysis.Results:Immunohistochemistry staining showed that the positive reaction of PTEN protein was all oriented to cytoplasm,which were brown or yellowishbrown granules.By way of X2 test,the significant difference of the positive expressions of PTEN protein between bone benign lesion and osteosarcoma (X2=7.976,P<0.01) was observed.Osteosarcoma with different degrees of histodifferentiation showed different level expression of PTEN protein.There was significant difference between well-differentiated osteosarcoma (grades Ⅰ-Ⅱ) and poorly-differentiated osteosarcoma (grade Ⅲ) statistically (P<0.01).The level of expression of PTEN was negatively correlated to the histological grade of osteosarcoma.There was great significance statistically (rs=-0.4922,P<0.01).Conclusion:PTEN protein may be used as candidate gene of cancer inhibitory gene:PTEN protein is a cancer suppressor gene protein which has expression in bone tumors.It might not only be used in the study of pulmonary carcinoma and neurogliocytoma,but also in the study of bone tumor; the expression of PTEN is related to benignancy or malignancy of bone tumor and their degree of differentiation.The expression of PTEN is

  12. Multiple forms of phosphatase from human brain: isolation and partial characterization of affi-gel blue nonbinding phosphatase activities.

    Science.gov (United States)

    Cheng, L Y; Wang, J Z; Gong, C X; Pei, J J; Zaidi, T; Grundke-Iqbal, I; Iqbal, K

    2001-04-01

    Phosphatases extracted from a human brain were resolved into two main groups, namely affi-gel blue-binding phosphatases and affi-gel blue-nonbinding phosphatases. Affi-gel blue binding phosphatases were further separated into four different phosphatase activities, designated P1-P4, and described previously. In the present study we describe the affi-gel blue-nonbinding phosphatases which were separated into seven different phosphatase activities, designated P5-P11 by poly-(L-lysine)-agarose and aminohexyl Sepharose 4B chromatographies. These seven phosphatase activities were active toward nonprotein phosphoester. P7-P11 and to some extent P5 could also dephosphorylate a phosphoprotein. They displayed different enzyme kinetics. On the basis of activity peak, the apparent molecular mass as estimated by Sephadex G-200 column chromatography for P5 was 49 kDa; P6, 32 kDa; P7, 150 kDa; P8, 250 kDa; P9, 165 kDa; P10, 90 kDa and P11, 165 kDa. Immunoblot analysis indicated that P8-P11 may belong to PP2B family, whereas P7 may associate with PP2A. The phosphatases P7-P11 were found to be effective in the dephosphorylation of Alzheimer's disease abnormally hyperphosphorylated tau. The resulting dephosphorylated tau regained its activity in promoting the microtubule assembly, suggesting that P7-P11 might regulate the phosphorylation of tau protein in the brain.

  13. Thymoquinone up-regulates PTEN expression and induces apoptosis in doxorubicin-resistant human breast cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Arafa, El-Shaimaa A.; Zhu Qianzheng [Department of Radiology, Ohio State University, Columbus, OH 43210 (United States); Shah, Zubair I. [James Cancer Hospital and Solove Research Institute, Ohio State University, Columbus, OH 43210 (United States); Wani, Gulzar; Barakat, Bassant M.; Racoma, Ira [Department of Radiology, Ohio State University, Columbus, OH 43210 (United States); El-Mahdy, Mohamed A., E-mail: Mohamed.el-mahdy@osumc.edu [Department of Radiology, Ohio State University, Columbus, OH 43210 (United States); Wani, Altaf A., E-mail: wani.2@osu.edu [Department of Radiology, Ohio State University, Columbus, OH 43210 (United States); Department of Molecular and Cellular Biochemistry, Ohio State University, Columbus, OH 43210 (United States); James Cancer Hospital and Solove Research Institute, Ohio State University, Columbus, OH 43210 (United States); DNA Research Chair, King Saud University, Riyadh (Saudi Arabia)

    2011-01-10

    The use of innocuous naturally occurring compounds to overcome drug resistance and cancer recalcitrance is now in the forefront of cancer research. Thymoquinone (TQ) is a bioactive constituent of the volatile oil derived from seeds of Nigella sativa Linn. TQ has shown promising anti-carcinogenic and anti-tumor activities through different mechanisms. However, the effect of TQ on cell signaling and survival pathways in resistant cancer cells has not been fully delineated. Here, we report that TQ greatly inhibits doxorubicin-resistant human breast cancer MCF-7/DOX cell proliferation. TQ treatment increased cellular levels of PTEN proteins, resulting in a substantial decrease of phosphorylated Akt, a known regulator of cell survival. The PTEN expression was accompanied with elevation of PTEN mRNA. TQ arrested MCF-7/DOX cells at G2/M phase and increased cellular levels of p53 and p21 proteins. Flow cytometric analysis and agarose gel electrophoresis revealed a significant increase in Sub-G1 cell population and appearance of DNA ladders following TQ treatment, indicating cellular apoptosis. TQ-induced apoptosis was associated with disrupted mitochondrial membrane potential and activation of caspases and PARP cleavage in MCF-7/DOX cells. Moreover, TQ treatment increased Bax/Bcl2 ratio via up-regulating Bax and down-regulating Bcl2 proteins. More importantly, PTEN silencing by target specific siRNA enabled the suppression of TQ-induced apoptosis resulting in increased cell survival. Our results reveal that up-regulation of the key upstream signaling factor, PTEN, in MCF-7/DOX cells inhibited Akt phosphorylation, which ultimately causes increase in their regulatory p53 levels affecting the induction of G2/M cell cycle arrest and apoptosis. Overall results provide mechanistic insights for understanding the molecular basis and utility of the anti-tumor activity of TQ.

  14. Structural mechanisms of plant glucan phosphatases in starch metabolism.

    Science.gov (United States)

    Meekins, David A; Vander Kooi, Craig W; Gentry, Matthew S

    2016-07-01

    Glucan phosphatases are a recently discovered class of enzymes that dephosphorylate starch and glycogen, thereby regulating energy metabolism. Plant genomes encode two glucan phosphatases, called Starch EXcess4 (SEX4) and Like Sex Four2 (LSF2), that regulate starch metabolism by selectively dephosphorylating glucose moieties within starch glucan chains. Recently, the structures of both SEX4 and LSF2 were determined, with and without phosphoglucan products bound, revealing the mechanism for their unique activities. This review explores the structural and enzymatic features of the plant glucan phosphatases, and outlines how they are uniquely adapted to perform their cellular functions. We outline the physical mechanisms used by SEX4 and LSF2 to interact with starch glucans: SEX4 binds glucan chains via a continuous glucan-binding platform comprising its dual-specificity phosphatase domain and carbohydrate-binding module, while LSF2 utilizes surface binding sites. SEX4 and LSF2 both contain a unique network of aromatic residues in their catalytic dual-specificity phosphatase domains that serve as glucan engagement platforms and are unique to the glucan phosphatases. We also discuss the phosphoglucan substrate specificities inherent to SEX4 and LSF2, and outline structural features within the active site that govern glucan orientation. This review defines the structural mechanism of the plant glucan phosphatases with respect to phosphatases, starch metabolism and protein-glucan interaction, thereby providing a framework for their application in both agricultural and industrial settings.

  15. Downregulation of protein tyrosine phosphatase PTP-BL represses adipogenesis.

    NARCIS (Netherlands)

    Glondu-Lassis, M.; Dromard, M.; Chavey, C.; Puech, C.; Fajas, L.; Hendriks, W.J.A.J.; Freiss, G.

    2009-01-01

    The insulin/insulin-like growth factor 1 (IGF-1) signaling pathway is a major regulator of adipose tissue growth and differentiation. We recently demonstrated that human protein tyrosine phosphatase (PTP) L1, a large cytoplasmic phosphatase also known as PTP-BAS/PTPN13/PTP-1E, is a negative

  16. Dissecting chronic lymphocytic leukemia microenvironment signals in patients with unmutated disease: microRNA-22 regulates phosphatase and tensin homolog/AKT/FOXO1 pathway in proliferative leukemic cells.

    Science.gov (United States)

    Palacios, Florencia; Prieto, Daniel; Abreu, Cecilia; Ruiz, Santiago; Morande, Pablo; Fernández-Calero, Tamara; Libisch, Gabriela; Landoni, Ana Inés; Oppezzo, Pablo

    2015-05-01

    Chronic lymphocytic leukemia (CLL) is characterized by the accumulation of clonal B cells arrested in G0/G1 stages that coexist with proliferative B cells. We identified one of these proliferative subsets in the peripheral blood from patients with unmutated disease (UM). Aiming to characterize the molecular mechanism underlying this proliferative behavior, we performed gene expression analysis of the mRNA and microRNAs in this leukemic subpopulation and compared results with those for the quiescent counterpart. Our results suggest that proliferation of this subset mainly depends on microRNA-22 overexpression, which induces phosphatase and tensin homolog (PTEN) down-regulation and phosphoinositide 3-kinase (PI3K)/AKT pathway activation. These results underline the role of the PI3K/AKT pathway at the origin of this proliferative pool in patients with UM CLL and provide additional rationale for the use of PI3K inhibitors.

  17. Lipid Metabolism Disorders

    Science.gov (United States)

    ... metabolic disorder, something goes wrong with this process. Lipid metabolism disorders, such as Gaucher disease and Tay-Sachs disease, involve lipids. Lipids are fats or fat-like substances. They ...

  18. Plant lipid signaling protocols

    NARCIS (Netherlands)

    Munnik, T.; Heilmann, I.

    2013-01-01

    Eukaryotic cells are surrounded by membranes consisting of various lipids, including sterols, sphingolipids, glycolipids, and phospholipids. Besides structural functions, membranes also contain lipids with regulatory and signaling roles. Such lipids include polyphosphoinositides, the low-abundant

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

    Directory of Open Access Journals (Sweden)

    Wei-Ru Huang

    Full Text Available Avian reovirus (ARV protein p17 has been shown to regulate cell cycle and autophagy by activation of p53/PTEN pathway; nevertheless, it is still uncle